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Office of Scientific and Technical Information
Quantum Gravity An introductory survey
E-Print Network (OSTI)
Quantum Gravity An introductory survey Hermann Nicolai Max-Planck-Institut f¨ur Gravitationsphysik (AlbertEinsteinInstitut, Potsdam) . p.1/25 #12;Why Quantum Gravity? . p.2/25 #12;Why Quantum Gravity theories: . p.2/25 #12;Why Quantum Gravity? General Relativity and Quantum Theory: not only very
Rossak, Wilhelm R.
Definition: Airborne Gravity Survey | Open Energy Information
Open Energy Info (EERE)
Survey Jump to: navigation, search Dictionary.png Airborne Gravity Survey Airborne gravity gradiometry (AGG) surveys provide information regarding the mass distribution of the...
On the no-gravity limit of gravity
We argue that Relative Locality may arise in the no gravity $G\\rightarrow0$ limit of gravity. In this limit gravity becomes a topological field theory of the BF type that, after coupling to particles, may effectively deform its dynamics. We briefly discuss another no gravity limit with a self dual ground state as well as the topological ultra strong $G\\rightarrow\\infty$ one.
Kowalski-Glikman, J
Ground Gravity Survey At Marysville Mt Area (Blackwell) | Open...
Ground Gravity Survey At Marysville Mt Area (Blackwell) Exploration Activity Details Location Marysville Mt Area Exploration Technique Ground Gravity Survey Activity Date...
Ground Gravity Survey At Mcgee Mountain Area (DOE GTP) | Open...
Ground Gravity Survey At Mcgee Mountain Area (DOE GTP) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Ground Gravity Survey At Mcgee Mountain...
Airborne Gravity Survey | Open Energy Information
Airborne Gravity Survey Airborne Gravity Survey Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: Airborne Gravity Survey Details Activities (0) Areas (0) Regions (0) NEPA(0) Exploration Technique Information Exploration Group: Geophysical Techniques Exploration Sub Group: Gravity Techniques Parent Exploration Technique: Gravity Techniques Information Provided by Technique Lithology: Distribution of density in the subsurface enables inference of rock type. Stratigraphic/Structural: Delineation of steeply dipping formations, geological discontinuities and faults, intrusions and the deposition of silicates due to hydrothermal activity. Hydrological: Density of sedimentary rocks are strongly influenced by fluid contained within pore space. Dry bulk density refers to the rock with no moisture, while the wet bulk density accounts for water saturation; fluid content may alter density by up to 30%.(Sharma, 1997)
Ground Gravity Survey | Open Energy Information
Ground Gravity Survey Ground Gravity Survey Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: Ground Gravity Survey Details Activities (48) Areas (34) Regions (2) NEPA(2) Exploration Technique Information Exploration Group: Geophysical Techniques Exploration Sub Group: Gravity Techniques Parent Exploration Technique: Gravity Techniques Information Provided by Technique Lithology: Distribution of density in the subsurface enables inference of rock type. Stratigraphic/Structural: Delineation of steeply dipping formations, geological discontinuities and faults, intrusions and large-scale deposition of silicates due to hydrothermal activity. Hydrological: Density of sedimentary rocks are strongly influenced by fluid contained within pore space. Dry bulk density refers to the rock with no moisture, while the wet bulk density accounts for water saturation; fluid content may alter density by up to 30%.(Sharma, 1997)
Definition: Ground Gravity Survey | Open Energy Information
Definition Definition Edit with form History Facebook icon Twitter icon » Definition: Ground Gravity Survey Jump to: navigation, search Dictionary.png Ground Gravity Survey The ground gravitational method is the study of the distribution of mass in the subsurface with the observation point at the earth's surface.[1] View on Wikipedia Wikipedia Definition A gravity anomaly is the difference between the observed acceleration of a planet's gravity and a value predicted from a model. A location with a positive anomaly exhibits more gravity than predicted, while a negative anomaly exhibits a lower value than predicted. References ↑ http://www.amazon.com/Geophysical-Field-Theory-Three-Volume-Gravitational/dp/0124020410 Ret Like Like You like this.Sign Up to see what your friends like.
Ground Gravity Survey At Dixie Valley Geothermal Field Area ...
Details Location Dixie Valley Geothermal Field Area Exploration Technique Ground Gravity Survey Activity Date Usefulness useful DOE-funding Unknown Notes The gravity data are...
Ground Gravity Survey At Valles Caldera - Sulphur Springs Area...
Gravity Survey Activity Date Usefulness not indicated DOE-funding Unknown Notes A computer program capable of two-dimensional modeling of gravity data was used in interpreting...
Ground Gravity Survey At Valles Caldera - Redondo Area (Wilt...
PPN-limit of Fourth Order Gravity inspired by Scalar-Tensor Gravity
Based on the {\\it dynamical} equivalence between higher order gravity and scalar-tensor gravity the PPN-limit of fourth order gravity is discussed. We exploit this analogy developing a fourth order gravity version of the Eddington PPN-parameters. As a result, Solar System experiments can be reconciled with higher order gravity, if physical constraints descending from experiments are fulfilled.
S. Capozziello; A. Troisi
Ground Gravity Survey At Blue Mountain Area (Fairbank Engineering...
to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Ground Gravity Survey At Blue Mountain Area (Fairbank Engineering, 2006) Exploration Activity...
Ground Gravity Survey At Newberry Caldera Area (DOE GTP) | Open...
GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Ground Gravity Survey At Newberry Caldera Area (DOE GTP) Exploration Activity Details Location Newberry Caldera Area...
Ground Gravity Survey At Under Steamboat Springs Area (Warpinski...
to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Ground Gravity Survey At Under Steamboat Springs Area (Warpinski, Et Al., 2002) Exploration Activity...
Ground Gravity Survey At San Francisco Volcanic Field Area (Warpinski...
Ground Gravity Survey At San Francisco Volcanic Field Area (Warpinski, Et Al., 2004) Exploration Activity Details Location San Francisco Volcanic Field Area Exploration Technique...
Ground Gravity Survey At Cove Fort Area - Vapor (Warpinski, Et...
to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Ground Gravity Survey At Cove Fort Area (Warpinski, Et Al., 2004) Exploration Activity Details...
Ground Gravity Survey At Lake City Hot Springs Area (Warpinski...
to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Ground Gravity Survey At Lake City Hot Springs Area (Warpinski, Et Al., 2004) Exploration Activity...
Ground Gravity Survey At Coso Geothermal Area (1980) | Open Energy...
Activity Details Location Coso Geothermal Area Exploration Technique Ground Gravity Survey Activity Date 1980 Usefulness not indicated DOE-funding Unknown Notes The...
Ground Gravity Survey At Kilauea East Rift Area (Broyles, Et...
Activity Details Location Kilauea East Rift Area Exploration Technique Ground Gravity Survey Activity Date Usefulness not indicated DOE-funding Unknown References M. L....
In Dixie Valley, Nevada Retrieved from "http:en.openei.orgwindex.php?titleGroundGravitySurveyAtDixieValleyGeothermalFieldArea(Blackwell,EtAl.,2009)&oldid38834...
to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Ground Gravity Survey At Under Steamboat Springs Area (Warpinski, Et Al., 2004) Exploration Activity...
Ground Gravity Survey At Walker Lake Valley Area (Shoffner, Et...
to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Ground Gravity Survey At Walker Lake Valley Area (Shoffner, Et Al., 2010) Exploration Activity...
Ground Gravity Survey At Baltazor Hot Springs Area (Isherwood...
to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Ground Gravity Survey At Baltazor Hot Springs Area (Isherwood & Mabey, 1978) Exploration Activity...
Ground Gravity Survey At Raft River Geothermal Area (1978) |...
Activity Details Location Raft River Geothermal Area Exploration Technique Ground Gravity Survey Activity Date 1978 Usefulness not indicated DOE-funding Unknown Exploration...
Ground Gravity Survey At Snake River Plain Region (DOE GTP) ...
Snake River Plain Region (DOE GTP) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Ground Gravity Survey At Snake River Plain Region (DOE GTP)...
Ground Gravity Survey At Coso Geothermal Area (1990) | Open Energy
Coso Geothermal Area (1990) Coso Geothermal Area (1990) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Ground Gravity Survey At Coso Geothermal Area (1990) Exploration Activity Details Location Coso Geothermal Area Exploration Technique Ground Gravity Survey Activity Date 1990 Usefulness not indicated DOE-funding Unknown Exploration Basis To identify features related to the heat source and to seek possible evidence for an underlying magma chamber Notes 2D and 3D gravity modeling was done using gridded Bouguer gravity data covering a 45 by 45 km region over the Coso geothermal area. Isostatic and terrain corrected Bouguer gravity data for about 1300 gravity stations were obtained from the US Geological Survey. After the data were checked, the gravity values were gridded at 1 km centers for the area of interest
Ground Gravity Survey At Maui Area (DOE GTP) | Open Energy Information
Ground Gravity Survey At Maui Area (DOE GTP) Exploration Activity Details Location Maui Area Exploration Technique Ground Gravity Survey Activity Date Usefulness not indicated...
Aeromagnetic and gravity surveys in the Coso Range, California | Open
and gravity surveys in the Coso Range, California and gravity surveys in the Coso Range, California Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: Aeromagnetic and gravity surveys in the Coso Range, California Details Activities (2) Areas (1) Regions (0) Abstract: The effect of an underlying magma reservoir cannot be identified within the complex gravity pattern in the Coso Range, California. Rather, linear gravity contours, which suggest a regional tectonic origin, enclose the location of most of the volcanic activity of the Coso Range. Faults along the edges of northwest trending, magnetic blocks probably provided paths of minimum resistance to the ascending viscous magma that was extruded as rhyolite domes. Dense, magnetic rocks associated with a complex mafic pluton 9 km in diameter form a relatively impermeable north border of
Ground Gravity Survey At Mokapu Penninsula Area (Thomas, 1986) | Open
Ground Gravity Survey At Mokapu Penninsula Area Ground Gravity Survey At Mokapu Penninsula Area (Thomas, 1986) Exploration Activity Details Location Mokapu Penninsula Area Exploration Technique Ground Gravity Survey Activity Date Usefulness not indicated DOE-funding Unknown Notes A separate geophysical analysis performed on the Koolau caldera area (Kauahikaua, 1981 a) synthesized existing self-potential, gravity, seismic and aeromagnetic data with recently acquired resistivity soundings. An analysis of the observed remnant magnetization within the caldera complex suggested that subsurface temperatures ranged from less than 300degrees C to no more than 540degrees C. The resistivity data indicated that the electrical basement, to a depth of 900 m, had resistivities ranging from 42 ohm.m to more than 1000 ohm.m, which is considered to be within the
Ground Gravity Survey At Truckhaven Area (Layman Energy Associates, 2009) |
Truckhaven Area (Layman Energy Associates, 2009) Truckhaven Area (Layman Energy Associates, 2009) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Ground Gravity Survey At Truckhaven Area (Layman Energy Associates, 2009) Exploration Activity Details Location Truckhaven Area Exploration Technique Ground Gravity Survey Activity Date Usefulness useful DOE-funding Unknown Notes The area of coverage for the DOE-funded geophysical surveys is shown in Figure 9. The 95 magnetotelluric (MT) soundings cover a central area of about 80 square kilometers. The 126 gravity stations extend over a broader area of about 150 square kilometers, centered on the same area covered by the MT soundings. A detailed description of the instrumentation and data acquisition procedures used for both surveys is provided in GSY-USA, Inc.
Waste Isolation Pilot Plant (WIPP) site gravity survey and interpretation
Science Conference Proceedings (OSTI)
A portion of the WIPP site has been extensively surveyed with high-precision gravity. The main survey (in T22S, R31E) covered a rectangular area 2 by 4-1/3 mi encompassing all of WIPP site Zone II and part of the disturbed zone to the north of the site. Stations were at 293-ft intervals along 13 north-south lines 880 ft apart. The data are considered accurate to within a few hundredths of a milligal. Long-wavelength gravity anomalies correlate well with seismic time structures on horizons below the Castile Formation. Both the gravity anomalies and the seismic time structures are interpreted as resulting from related density and velocity variations within the Ochoan Series. Shorter wavelength negative gravity anomalies are interpreted as resulting from bulk density alteration in the vicinity of karst conduits. The WIPP gravity survey was unable to resolve low-amplitude, long-wavelength anomalies that should result from the geologic structures within the disturbed zone. It did indicate the degree and character of karst development within the surveyed area.
Barrows, L.J.; Fett, J.D.
Ground Gravity Survey At Lake City Hot Springs Area (Warpinski, Et Al.,
Lake City Hot Springs Area (Warpinski, Et Al., Lake City Hot Springs Area (Warpinski, Et Al., 2004) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Ground Gravity Survey At Lake City Hot Springs Area (Warpinski, Et Al., 2004) Exploration Activity Details Location Lake City Hot Springs Area Exploration Technique Ground Gravity Survey Activity Date Usefulness not indicated DOE-funding Unknown Notes The Lake City site, which is located in far northeastern California, consists of a previously identified geothermal site that has been explored with both geophysics and drilling (Hedel, 1981), but has not been characterized adequately to allow accurate siting or drilling of production wells. Some deep wells, several seismic lines, limited gravity surveys, and geochemical and geological studies have suggested that the geothermal
Principal facts for a gravity survey of Summer Lake Known Geothermal Resource Area, Oregon
DOE Green Energy (OSTI)
Gravity survey data are tabulated for 73 stations. Site latitude, longitude, elevation, observed gravity, theoretical gravity, free-air correction, Bouguer correction, and the simple Bouguer anomaly are included. (WHK)
Peterson, D.L.; Meyer, R.F.
Gravity survey of the southwestern part of the sourthern Utah geothermal belt
A gravity survey covering an area of 6200 km/sup 2/ was made over the southwestern part of the southern Utah geothermal belt. The objective of the gravity survey is to delineate the geologic structures and assist in the understanding of the geothermal potential of the area. A total of 726 new gravity stations together with 205 existing gravity stations, are reduced to give: (1) a complete Bouguer gravity anomaly map, and (2) a fourth-order residual gravity anomaly map; both maps have a 2-mgal contour interval. The complete Bouguer gravity anomaly map shows an east-trending regional gravity belt with a total relief of about 70 mgal which crosses the central portion of the survey area. The gravity belt is attributed to a crustal lateral density variation of 0.1 gm/cc from a depth of 5 to 15 km.
Green, R.T.; Cook, K.L.
Ground Gravity Survey At Clear Lake Area (Skokan, 1993) | Open Energy
Ground Gravity Survey At Clear Lake Area (Skokan, 1993) Ground Gravity Survey At Clear Lake Area (Skokan, 1993) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Ground Gravity Survey At Clear Lake Area (Skokan, 1993) Exploration Activity Details Location Clear Lake Area Exploration Technique Ground Gravity Survey Activity Date Usefulness useful DOE-funding Unknown Notes A detailed gravity survey (Isherwood, 1975) was undertaken as a follow-up to a regional gravity survey of the area in order to detail a low in the Clear Lake volcanics. The low (Fig. 5 ) was thought to be caused by an intrusion of molten rock which would be mass deficient. Modeling and interpretation indicated a+K139 chamber-like feature with a radius of approximately 7 km within 7-8 km of the surface. References
Ground Gravity Survey At Baltazor Hot Springs Area (Isherwood & Mabey,
Ground Gravity Survey At Baltazor Hot Springs Area (Isherwood & Mabey, Ground Gravity Survey At Baltazor Hot Springs Area (Isherwood & Mabey, 1978) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Ground Gravity Survey At Baltazor Hot Springs Area (Isherwood & Mabey, 1978) Exploration Activity Details Location Baltazor Hot Springs Area Exploration Technique Ground Gravity Survey Activity Date Usefulness not indicated DOE-funding Unknown Notes The gravity map of the Baltazor KGRA (Fig. 2) shows a gravity low within the valley area that presumably is related to low-density Cenozoic sediments. The steep gravity gradient along the east side of the valley suggests a north-trending normal fault. The thickness of low-density fill is estimated to be about 300 m in the southwestern part of the KGRA and
Ground Gravity Survey At San Emidio Desert Area (DOE GTP) | Open...
Activity Details Location San Emidio Desert Area Exploration Technique Ground Gravity Survey Activity Date Usefulness not indicated DOE-funding Unknown Notes (prior to...
Ground Gravity Survey At Hot Pot Area (DOE GTP) | Open Energy...
Ground Gravity Survey Activity Date Usefulness not indicated DOE-funding Unknown Notes prior References (1 January 2011) GTP ARRA Spreadsheet Retrieved from "http:en.openei.org...
Ground Gravity Survey At New River Area (DOE GTP) | Open Energy...
GTP) Exploration Activity Details Location New River Area Exploration Technique Ground Gravity Survey Activity Date Usefulness not indicated DOE-funding Unknown References (1...
Ground Gravity Survey At Fort Bliss Area (DOE GTP) | Open Energy...
Ground Gravity Survey Activity Date Usefulness not indicated DOE-funding Unknown References (1 January 2011) GTP ARRA Spreadsheet Retrieved from "http:en.openei.orgw...
Ground Gravity Survey At Kilauea East Rift Area (Leslie, Et Al...
to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Ground Gravity Survey At Kilauea East Rift Area (Leslie, Et Al., 2004) Exploration Activity Details...
Ground Gravity Survey At U.S. West Region (Aiken & Ander, 1981...
to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Ground Gravity Survey At U.S. West Region (Aiken & Ander, 1981) Exploration Activity Details...
Ground Gravity Survey At Glass Buttes Area (DOE GTP) | Open Energy...
Glass Buttes Area (DOE GTP) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Ground Gravity Survey At Glass Buttes Area (DOE GTP) Exploration...
Ground Gravity Survey At Under Steamboat Springs Area (Warpinski, Et Al.,
Ground Gravity Survey At Under Steamboat Springs Area (Warpinski, Et Al., Ground Gravity Survey At Under Steamboat Springs Area (Warpinski, Et Al., 2002) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Ground Gravity Survey At Under Steamboat Springs Area (Warpinski, Et Al., 2002) Exploration Activity Details Location Under Steamboat Springs Area Exploration Technique Ground Gravity Survey Activity Date Usefulness useful DOE-funding Unknown Notes This project consisted of (1) a 3-D surface seismic survey conducted in the fall of 2000, (2) a micro-seismic survey run from November 2000 to April 200 1, and (3) a gravity survey conducted in April and May 2001. The 3-D surface seismic data are still being processed at this time, but initial results indicate that there are two major lineations of high velocity
Ground Gravity Survey At Raft River Geothermal Area (1957-1961) | Open
Ground Gravity Survey At Raft River Geothermal Area (1957-1961) Ground Gravity Survey At Raft River Geothermal Area (1957-1961) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Ground Gravity Survey At Raft River Geothermal Area (1957-1961) Exploration Activity Details Location Raft River Geothermal Area Exploration Technique Ground Gravity Survey Activity Date 1957 - 1961 Usefulness not indicated DOE-funding Unknown Notes From 1957 to 1961 a regional gravity survey was made over the northern part of the Great Salt Lake Desert and adjacent areas in Utah, eastern Nevada, and southeastern Idaho. A total of 1040 stations were taken over an area of about 7000 square miles. The results were compiled as a Bouguer gravity anomaly map with a contour interval of 2 mgal. The Bouguer values ranged
Ground Gravity Survey At Valles Caldera - Redondo Area (Wilt & Haar, 1986)
Gravity Survey At Valles Caldera - Redondo Area (Wilt & Haar, 1986) Gravity Survey At Valles Caldera - Redondo Area (Wilt & Haar, 1986) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Ground Gravity Survey At Valles Caldera - Redondo Area (Wilt & Haar, 1986) Exploration Activity Details Location Valles Caldera - Redondo Area Exploration Technique Ground Gravity Survey Activity Date Usefulness not indicated DOE-funding Unknown Notes A computer program capable of two-dimensional modeling of gravity data was used in interpreting gravity observations along profiles A--A' and B--B' (Talwani et al., 1959). Densities of 2.12, 2.40, and 2.65 g/cm a were used for modeling the near-surface caldera fill, the underlying volcanics, and the basement sections, respectively (Fig. 8). Although correlation with
Regional gravity and aeromagnetic surveys of the Mineral Mountains and vicinity, Millard and Beaver Counties, Utah
The results of gravity and aeromagnetic surveys of the Mineral Mountains and vicinity are presented as a terrain-corrected Bouguer gravity anomaly map (about 1450 stations with 1-mgal contour interval) and a total magnetic field intensity residual anomaly map (with contour interval 50 gammas), respectively. Combined interpretation of the gravity and aeromagnetic data was conducted based on comparing and contrasting various processed maps and interpretative geologic cross sections produced from each survey. (MHR)
Carter, J.A.; Cook, K.L.
Ground Gravity Survey At Cove Fort Area (Warpinski, Et Al., 2004) | Open
Ground Gravity Survey At Cove Fort Area (Warpinski, Et Al., 2004) Ground Gravity Survey At Cove Fort Area (Warpinski, Et Al., 2004) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Ground Gravity Survey At Cove Fort Area (Warpinski, Et Al., 2004) Exploration Activity Details Location Cove Fort Geothermal Area Exploration Technique Ground Gravity Survey Activity Date Usefulness not indicated DOE-funding Unknown Notes Update to Warpinski, et al., 2002 References N. R. Warpinski, A. R. Sattler, R. Fortuna, D. A. Sanchez, J. Nathwani (2004) Geothermal Resource Exploration And Definition Projects Retrieved from "http://en.openei.org/w/index.php?title=Ground_Gravity_Survey_At_Cove_Fort_Area_(Warpinski,_Et_Al.,_2004)&oldid=598130" Categories: Exploration Activities DOE Funded Activities
Ground Gravity Survey At Lightning Dock Area (Cunniff & Bowers, 2005) |
Ground Gravity Survey At Lightning Dock Area (Cunniff Ground Gravity Survey At Lightning Dock Area (Cunniff & Bowers, 2005) Exploration Activity Details Location Lightning Dock Area Exploration Technique Ground Gravity Survey Activity Date Usefulness useful DOE-funding Unknown Notes Two separate gravity surveys were conducted by LDG as part of this GRED Cooperative Agreement. The first survey was conducted in April 2001 and consisted of 77 stations in the north half of Section 7 and south half of Section 6, both sections being in Township 25 South, Range 19 West. A second and much larger survey was conducted in October 2001. This survey consisted of 227 new stations in nine linear traverses that covered more than one hundred (100) square kilometers centered on the known resource area in Section 7 (figure 3).
Regional Gravity Survey of the Northern Great Salt Lake Desert and Adjacent
Gravity Survey of the Northern Great Salt Lake Desert and Adjacent Gravity Survey of the Northern Great Salt Lake Desert and Adjacent Areas in Utah, Nevada, and Idaho Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: Regional Gravity Survey of the Northern Great Salt Lake Desert and Adjacent Areas in Utah, Nevada, and Idaho Details Activities (1) Areas (1) Regions (0) Abstract: From 1957 to 1961 a regional gravity survey was made over the northern part of the Great Salt Lake Desert and adjacent areas in Utah, eastern Nevada, and southeastern Idaho. A total of 1040 stations were taken over an area of about 7000 square miles. The results were compiled as a Bouguer gravity anomaly map with a contour interval of 2 mgal. The Bouguer values ranged from a high of about -120 mgal over the outcrop areas to a
Ground Gravity Survey At Cove Fort Area - Vapor (Warpinski, Et Al., 2002) |
Ground Gravity Survey At Cove Fort Area - Vapor (Warpinski, Et Al., 2002) Ground Gravity Survey At Cove Fort Area - Vapor (Warpinski, Et Al., 2002) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Ground Gravity Survey At Cove Fort Area (Warpinski, Et Al., 2002) Exploration Activity Details Location Cove Fort Geothermal Area Exploration Technique Ground Gravity Survey Activity Date Usefulness not indicated DOE-funding Unknown Notes The project at Cove Fort/Sulphurdale in Utah, T26S R6/7W, is concerned with locating and drilling a 900-meter well to explore the western extension of the Cove Fort-Sulphurdale geothermal area. The geophysical exploration consisted of resistivity, ground magnetic, and microgravity surveys that were made to site the well in an optimum location. References N. R. Warpinski, A. R. Sattlerl, D. A. Sanchez (2002) Geothermal
Ground Gravity Survey At Dixie Valley Geothermal Field Area (Blackwell, Et
Blackwell, Et Blackwell, Et Al., 2009) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Ground Gravity Survey At Dixie Valley Geothermal Field Area (Blackwell, Et Al., 2009) Exploration Activity Details Location Dixie Valley Geothermal Field Area Exploration Technique Ground Gravity Survey Activity Date Usefulness useful DOE-funding Unknown Notes "The gravity data are described by (Blackwell et al., 1999; 2002). On a basin-wide scale the gravity low in Dixie Valley is strongly asymmetrical from east to west. The west side is relatively well-defined by rapid horizontal changes in the gravity anomaly value, whereas along the east side horizontal changes are more subdued and often consist of several steps. The horizontal gradient of the gravity field has proved most useful
Regional Gravity Survey of the Northern Great Salt Lake Desert...
of the Northern Great Salt Lake Desert and Adjacent Areas in Utah, Nevada, and Idaho Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: Regional Gravity...
Ground Gravity Survey At Lightning Dock Area (Warpinski, Et Al., 2002) |
source source History View New Pages Recent Changes All Special Pages Semantic Search/Querying Get Involved Help Apps Datasets Community Login | Sign Up Search Page Edit History Facebook icon Twitter icon » Ground Gravity Survey At Lightning Dock Area (Warpinski, Et Al., 2002) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Ground Gravity Survey At Lightning Dock Area (Warpinski, Et Al., 2002) Exploration Activity Details Location Lightning Dock Area Exploration Technique Ground Gravity Survey Activity Date Usefulness not indicated DOE-funding Unknown Notes As a foundation for successful siting and drilling a deep test well, additional geophysical work has been completed including gravity, resistivity, and airborne magnetic surveys. Several new seismic profiles
Gravity survey of Dixie Valley, west-central Nevada | Open Energy...
Number 82-111 DOI Not Provided Check for DOI availability: http:crossref.org Online Internet link for Gravity survey of Dixie Valley, west-central Nevada Citation Donald H....
Ground Gravity Survey At Truckhaven Area (Warpinski, Et Al., 2004) | Open
Gravity Survey At Truckhaven Area (Warpinski, Gravity Survey At Truckhaven Area (Warpinski, Et Al., 2004) Exploration Activity Details Location Truckhaven Area Exploration Technique Ground Gravity Survey Activity Date Usefulness useful DOE-funding Unknown Notes The Truckhaven project, which is located on the west flank of the Salton Trough in southern California, is north and west of several existing geothermal power generation facilities in the trough. An extensive shallow geothermal anomaly is known to exist in this area and this region corresponds to a gravity high, which has been further delineated by the drilling of numerous shallow temperature gradient wells and one deep, abandoned, test well. Layman Energy Associates has performed Phase I exploration tasks to further constrain the anomaly, including a detailed
Ground Gravity Survey At Kilauea East Rift Area (Thomas, 1986) | Open
Ground Gravity Survey At Kilauea East Rift Area Ground Gravity Survey At Kilauea East Rift Area (Thomas, 1986) Exploration Activity Details Location Kilauea East Rift Area Exploration Technique Ground Gravity Survey Activity Date Usefulness useful DOE-funding Unknown Notes This model was later expanded through the examination of detailed and regional gravity data (Krivoy and Eaton, 1961) and regional aeromagnetic data (Malahoff and Woollard, 1966) to a three-dimensional map of the rift zone (Furumoto, 1978b). This model projected a dike complex (presumably at high temperatures) which has a width of approximately 20 km near the summit of Kilauea that narrows to approximately 12 km at the lower quarter of the subaerial portion of the rift (Fig. 52). References Donald M. Thomas (1 January 1986) Geothermal Resources Assessment In
Ground Gravity Survey At Rio Grande Rift Region (Aiken & Ander, 1981) |
Rio Grande Rift Region (Aiken & Ander, 1981) Rio Grande Rift Region (Aiken & Ander, 1981) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Ground Gravity Survey At Rio Grande Rift Region (Aiken & Ander, 1981) Exploration Activity Details Location Rio Grande Rift Geothermal Region Exploration Technique Ground Gravity Survey Activity Date Usefulness useful DOE-funding Unknown References Carlos L.V. Aiken, Mark E. Ander (1981) A Regional Strategy For Geothermal Exploration With Emphasis On Gravity And Magnetotellurics Retrieved from "http://en.openei.org/w/index.php?title=Ground_Gravity_Survey_At_Rio_Grande_Rift_Region_(Aiken_%26_Ander,_1981)&oldid=401473" Category: Exploration Activities What links here Related changes Special pages Printable version
Detailed gravity and aeromagnetic surveys in the Black Rock Desert Area, Utah. Topical report
Aeromagnetic and gravity surveys were conducted during 1978 in the Black Rock Desert, Utah over an area of about 2400 km/sup 2/ between the north-trending Pavant and Cricket Mountains. The surveys assisted in evaluating the geothermal resources in the Meadow-Hatton Known Geothermal Resource Area (KGRA) and vicinity by delineating geophysical characteristics of the subsurface. The gravity measurements from approximately 700 new stations were reduced to complete Bouguer gravity anomaly values with the aid of a computerized terrain-correction program and contoured at an interval of 1 milligal. The aeromagnetic survey was drape flown at an altitude of 305 m (1000 ft) and a total intensity residual aeromagnetic map with a contour interval of 20 gammas was produced. Two gravity and aeromagnetic east-west profiles and one north-south profile were modeled using a simultaneous 2 1/2-dimensional modeling technique to provide a single model satisfying both types of geophysical data.
Serpa, L.F.; Cook, K.L.
Limits from Weak Gravity Conjecture on Dark Energy Models
The weak gravity conjecture has been proposed as a criterion to distinguish the landscape from the swampland in string theory. As an application in cosmology of this conjecture, we use it to impose theoretical constraint on parameters of two types of dark energy models. Our analysis indicates that the Chaplygin-gas-type models realized in quintessence field are in the swampland, whereas the $a$ power-low decay model of the variable cosmological constant can be viable but the parameters are tightly constrained by the conjecture.
Xing Wu; Zong-Hong Zhu
Ground Gravity Survey At Valles Caldera - Sulphur Springs Area (Wilt &
Valles Caldera - Sulphur Springs Area (Wilt & Valles Caldera - Sulphur Springs Area (Wilt & Haar, 1986) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Ground Gravity Survey At Valles Caldera - Sulphur Springs Area (Wilt & Haar, 1986) Exploration Activity Details Location Valles Caldera - Sulphur Springs Area Exploration Technique Ground Gravity Survey Activity Date Usefulness not indicated DOE-funding Unknown Notes A computer program capable of two-dimensional modeling of gravity data was used in interpreting gravity observations along profiles A--A' and B--B' (Talwani et al., 1959). Densities of 2.12, 2.40, and 2.65 g/cm a were used for modeling the near-surface caldera fill, the underlying volcanics, and the basement sections, respectively (Fig. 8). Although correlation with
A Sea Floor Gravity Survey of the Sleipner Field to Monitor CO2 Migration
Carbon dioxide gas (CO{sub 2}) is a byproduct of many wells that produce natural gas. Frequently the CO{sub 2} separated from the valuable fossil fuel gas is released into the atmosphere. This adds to the growing problem of the climatic consequences of greenhouse gas contamination. In the Sleipner North Sea natural gas production facility, the separated CO{sub 2} is injected into an underground saline aquifer to be forever sequestered. Monitoring the fate of such sequestered material is important - and difficult. Local change in Earth's gravity field over the injected gas is one way to detect the CO{sub 2} and track its migration within the reservoir over time. The density of the injected gas is less than that of the brine that becomes displaced from the pore space of the formation, leading to slight but detectable decrease in gravity observed on the seafloor above the reservoir. Using equipment developed at Scripps Institution of Oceanography, we have been monitoring gravity over the Sleipner CO{sub 2} sequestration reservoir since 2002. We surveyed the field in 2009 in a project jointly funded by a consortium of European oil and gas companies and the US Department of Energy. The value of gravity at some 30 benchmarks on the seafloor, emplaced at the beginning of the monitoring project, was observed in a week-long survey with a remotely operated vehicle. Three gravity meters were deployed on the benchmarks multiple times in a campaign-style survey, and the measured gravity values compared to those collected in earlier surveys. A clear signature in the map of gravity differences is well correlated with repeated seismic surveys.
Mark Zumberge
Ground Gravity Survey At Long Valley Caldera Area (Farrar, Et Al., 2003) |
Ground Gravity Survey At Long Valley Caldera Area Ground Gravity Survey At Long Valley Caldera Area (Farrar, Et Al., 2003) Exploration Activity Details Location Long Valley Caldera Area Exploration Technique Ground Gravity Survey Activity Date Usefulness useful DOE-funding Unknown Notes Modeling of both deformation and microgravity data now suggests that (1) there are two inflation sources beneath the caldera, a shallower source 7-10 km beneath the resurgent dome and a deeper source ~15 km beneath the caldera's south moat and (2) the shallower source may contain components of magmatic brine and gas. At shallow depths in the caldera References Christopher D. Farrar, Michael L. Sorey, Evelyn Roeloffs, Devin L. Galloway, James F. Howle, Ronald Jacobson (2003) Inferences On The Hydrothermal System Beneath The Resurgent Dome In Long Valley Caldera,
Ground Gravity Survey At San Francisco Volcanic Field Area (Warpinski, Et
4) 4) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Ground Gravity Survey At San Francisco Volcanic Field Area (Warpinski, Et Al., 2004) Exploration Activity Details Location San Francisco Volcanic Field Area Exploration Technique Ground Gravity Survey Activity Date Usefulness not indicated DOE-funding Unknown Notes Northern Arizona University has re-assessed the existing exploration data, geologically mapped the target area, obtained rock samples for age dating and mineral chemistry, performed gravity and magnetic surveys, and integrated these results to identify potential drilling targets and sites. Further work may occur in 2004 or 2005. References N. R. Warpinski, A. R. Sattler, R. Fortuna, D. A. Sanchez, J. Nathwani (2004) Geothermal Resource Exploration And Definition Projects
Ground Gravity Survey At Chocolate Mountains Area (Alm, Et Al., 2010) |
Chocolate Mountains Area (Alm, Et Al., 2010) Chocolate Mountains Area (Alm, Et Al., 2010) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Ground Gravity Survey At Chocolate Mountains Area (Alm, Et Al., 2010) Exploration Activity Details Location Chocolate Mountains Area Exploration Technique Ground Gravity Survey Activity Date Usefulness useful DOE-funding Unknown Notes Gravity and ground-based magnetics surveys were conducted during the summer of 2008. This data was acquired to aid in the identification of structures without fair surface expression, obscured by recent deposition. References Steve Alm, S. Bjornstad, M. Lazaro, A. Sabin1, D. Meade, J. Shoffner, W. C. Huang, J. Unruh, M. Strane, H. Ross (2010) Geothermal Energy Resource Investigations, Chocolate Mountains Aerial Gunnery Range,
Ground Gravity Survey At Salt Wells Area (Bureau of Land Management, 2009)
Salt Wells Area (Bureau of Land Management, 2009) Salt Wells Area (Bureau of Land Management, 2009) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Ground Gravity Survey At Salt Wells Area (Bureau of Land Management, 2009) Exploration Activity Details Location Salt Wells Geothermal Area Exploration Technique Ground Gravity Survey Activity Date 2008 - 2008 Usefulness not indicated DOE-funding Unknown Exploration Basis Vulcan increased exploration efforts in the summer and fall of 2008, during which time the company drilled two temperature gradient holes (86-15 O on Pad 1 and 17-16 O on Pad 3); conducted seismic, gravity and magnetotelluric surveys; and drilled deep exploration wells at Pads 6 and 8 and binary wells at Pads 1, 2, 4, and 7. Notes Data from these wells is proprietary, and so were unavailable for inclusion
Ground Gravity Survey At Long Valley Caldera Area (Laney, 2005) | Open
Ground Gravity Survey At Long Valley Caldera Area Ground Gravity Survey At Long Valley Caldera Area (Laney, 2005) Exploration Activity Details Location Long Valley Caldera Area Exploration Technique Ground Gravity Survey Activity Date Usefulness not indicated DOE-funding Unknown Notes Localized Strain as a Discriminator of Hidden Geothermal Systems, Vasco and Foxall, 2005. Recent work has focused on (1) collaborating with Alessandro Ferretti to use Permanent Scatterer (PS) InSAR data to infer strain at depth, (2) working with Lane Johnson to develop a dynamic faulting model, and (3) acquiring InSAR data for the region surrounding the Dixie Valley fault zone in collaboration with Dr. William Foxall of LLNL. The InSAR data have been processed and an initial interpretation of the results is ongoing. In particular, we have InSAR stacks for over twenty pairs of
Gravity survey of Dixie Valley, west-central Nevada
Dixie Valley, a northeast-trending structural trough typical of valleys in the Basin and Range Province, is filled with a maximum of about 10,000 feet of alluvial and lacustrine deposits, as estimated from residual-gravity measurements obtained in this study. On the basis of gravity measurements at 300 stations on nine east-west profiles, the gravity residuals reach a maximum of 30 milliGals near the south-central part of the valley. Results from a three-dimensional inversion model indicate that the central depression of the valley is offset to the west of the geographic axis. This offset is probably due to major faulting along the west side of the valley adjacent to the Stillwater Range. Comparison of depths to bedrock obtained during this study and depths obtained from a previous seismic-refraction study indicates a reasonably good correlation. A heterogeneous distribution of densities within the valley-fill deposits would account for differing depths determined by the two methods. 17 refs., 4 figs., 2 tabs.
Schaefer, D.H.
Gravity survey of the Escalante Desert and vicinity, in Iron and Washington Counties, Utah
During the summers of 1978 and 1979, a total of 436 new gravity stations were taken in the southern part of the Escalante Desert and vicinity in Iron and Washington counties, Utah. The new stations were combined with 917 other stations taken in previous surveys, and a total of 1353 stations were used in this study, covering an area of about 2700 mi/sup 2/ (7000 km/sup 2/). The purpose of the study was to help evaluate the potential of geothermal resources within the survey area, which includes the Newcastle and Lund KGRA's. All the gravity data were terrain corrected out to a radial distance of 166.7 km from each station, using a computer terrain-correction program. The data were compiled and presented as a complete Bouguer gravity anomaly map with a 2-mgal contour interval. A geologic interpretation of the gravity data was made qualitatively from the gravity map and also quantitatively from four easterly trending gravity profiles taken across the area.
Pe, W.; Cook, K.L.
Dixie Valley Geothermal Dixie Valley Geothermal Field Area (Blackwell, Et Al., 2003) Exploration Activity Details Location Dixie Valley Geothermal Field Area Exploration Technique Ground Gravity Survey Activity Date Usefulness useful DOE-funding Unknown Notes The gravity data are not as site specific as the seismic, but put the major parts of the structure in their proper location and places vital constraints on the possible interpretations of the seismic data. References D. D. Blackwell, K. W. Wisian, M. C. Richards, Mark Leidig, Richard Smith, Jason McKenna (2003) Geothermal Resource Analysis And Structure Of Basin And Range Systems, Especially Dixie Valley Geothermal Field, Nevada Retrieved from "http://en.openei.org/w/index.php?title=Ground_Gravity_Survey_At_Dixie_Valley_Geothermal_Field_Area_(Blackwell,_Et_Al.,_2003)&oldid=388459
Ground Gravity Survey At Cove Fort Area (Toksoz, Et Al, 2010) | Open Energy
Cove Fort Area (Toksoz, Et Al, 2010) Cove Fort Area (Toksoz, Et Al, 2010) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Ground Gravity Survey At Cove Fort Area (Toksoz, Et Al, 2010) Exploration Activity Details Location Cove Fort Geothermal Area Exploration Technique Ground Gravity Survey Activity Date Usefulness not indicated DOE-funding Unknown Notes We have collected various geophysical data around the geothermal field, including heat flow, gravity, MT, seismic surface wave phase and group velocity maps, seismic body wave travel time data and full seismic waveforms. All of these geophysical data sets have different strengths on characterizing subsurface structures and properties. Combining these data through a coordinated analysis and, when possible, by joint inversion
Evaluation of low-temperature geothermal potential in Utah and Goshen Valleys and adjacent areas, Utah. Part I. Gravity survey
During 1980 and 1981 a total of 569 new gravity stations were taken in Utah and Goshen Valleys and adjacent areas, Utah. The new stations were combined with 530 other gravity stations taken in previous surveys which resulted in a compilation of 1099 stations which were used in this study. The additional surveys were undertaken to assist in the evaluation of the area for the possible development of geothermal resources by providing an interpreted structural framework by delineating faults, structural trends, intrusions, thickness of valley fill, and increased density of host rock. The gravity data are presented as (1) a complete Bouguer gravity anomaly map with a 2 mgal contour interval on a scale of 1:100,000 and (2) five generally east-trending gravity profiles. A geologic interpretation of the study area was made from the gravity map and from the interpretive geologic cross sections which were modeled along the gravity profiles.
Davis, D.A.; Cook, K.L.
Gravity survey of the Cove Fort-Sulphurdale KGRA and the north Mineral Mountains area, Millard and Beaver Counties, Utah
During the summers of 1975 and 1976, a gravity survey was conducted in the Cove Fort-Sulphurdale KGRA and north Mineral Mountains area, Millard and Beaver Counties, Utah. The survey consisted of 671 gravity stations covering an area of about 1300 km{sup 2}, and included two orthogonal gravity profiles traversing the area. The gravity data are presented as a terrain-corrected Bouguer gravity anomaly map with a contour interval of 1 mgal and as an isometric three-dimensional gravity anomaly surface. Selected anomaly separation techniques were applied to the hand-digitized gravity data (at 1-km intervals on the Universal Transverse Mercator grid) in both the frequency and space domains, including Fourier decomposition, second vertical derivative, strike-filter, and polynomial fitting analysis, respectively.
Brumbaugh, W.D.; Cook, K.L.
Performance limits of gravity-assist heat pipes with simple wick structures
SciTech Connect
Experiments using gravity-assist heat pipes with simple wick structures were used to establish performance limits due to entrainment of the liquid by the counterflowing vapor. A physical model is postulated which leads to a single correlation predicting entrainment limits for all data investigated. The characteristic length in the entrainment parameter is the depth of the wick structure and the model infers an upper bound on this parameter.
Prenger, F.C. Jr.; Kemme, J.E.
Ground Gravity Survey At Cove Fort Area (Warpinski, Et Al., 2002) | Open
Jump to: navigation, search Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Ground Gravity Survey At Cove Fort Area (Warpinski, Et Al., 2002) Exploration Activity Details Location Cove Fort Geothermal Area Exploration Technique Ground Gravity Survey Activity Date Usefulness not indicated DOE-funding Unknown Notes The project at Cove Fort/Sulphurdale in Utah, T26S R6/7W, is concerned with locating and drilling a 900-meter well to explore the western extension of the Cove Fort-Sulphurdale geothermal area. The geophysical exploration consisted of resistivity, ground magnetic, and microgravity surveys that were made to site the well in an optimum location. References N. R. Warpinski, A. R. Sattlerl, D. A. Sanchez (2002) Geothermal Resource Exploration And Definition Project
Gravity and ground magnetic surveys of the Thermo Hot Springs KGRA region, Beaver County, Utah
During the period June to September 1976, gravity and ground magnetic surveys were made in the Thermo Hot Springs KGRA region which is located southwest of the town of Milford, Beaver County, Utah. The regional surveys comprised 273 new gravity and magnetic stations and incorporated 104 previous gravity stations over an area of approximately 620 km{sup 2}. The detailed surveys consisted of 9 east-west profiles in the immediate vicinity of the Thermo Hot Springs KGRA. The gravity data were reduced and are presented as terrain-corrected Bouguer gravity anomaly maps. Terrain corrections were made to a distance of 18.8 km. The regional gravity map shows the following features: (1) a large north-south trend with total relief of 5 mgal extending through the central portion of the study area; (2) an east-west trend with relief of about 7-8 mgal south of the Star Range and Shauntie Hills; (3) a north-south trend with 5 mgal relief east of Blue Mountain; and (4) a broad low of approximately 5 mgal closure southwest of the Shauntie Hills. The trends are probably caused by major faults and the gravity low is probably caused by the southern end of the Wah Wah Valley graben. The detailed gravity map indicates two possible east-west trending faults intersecting a major north-south trending fault in the immediate vicinity of the Thermo Hot Springs. The location of the hot springs appears to be fault controlled. To facilitate interpretation of the gravity data, the following processing and modeling techniques were used: (1) high-pass frequency filtering; (2) polynomial fitting; (3) second derivative; (4) strike filtering; (5) two-dimensional modeling; and (6) three-dimensional modeling. These techniques proved helpful as they more clearly delineated features of interest. The residual maps outlined an elongate north-south graben that extends through the survey area. The strike-filtered maps emphasize the major north-south and east-west faults of the region. Modeling provided reasonable depth estimates for bedrock in the vicinity of the hot springs and supported the structural interpretation for the hot springs area. The magnetic data are presented as total magnetic intensity anomaly maps for both the regional and detailed surveys. The regional map delineates a magnetic high with 600-gammas closure that corresponds to a Tertiary quartz monzonite intrusive in the northeast part of the survey area. An east-west trend with about 300-gammas relief is delineated south of the Shauntie Hills and Star Range and possibly corresponds to an east-west fault. The detailed magnetic map outlines an anomalous low with nearly 100-gammas closure associated with the Thermo Hot Springs. This magnetic low may reflect an alteration zone which is structurally controlled. The following processing and modeling techniques were applied to aid interpretation of the magnetic data: (1) low-pass frequency filtering; (2) strike-filtering; (3) pseudogravity; (4) two and one-half dimensional modeling; and (5) three-dimensional modeling. The low-pass filtering clearly delineates the intrusive and the east-west trend south of the Star Range. The strike-filtering outlines north-south and east-west trends which correlate with faults implied by gravity data. The pseudogravity map indicates that the magnetic and gravity anomalies are not caused by the same bodies. The two and one-half dimensional modeling in the hot springs area provides a possible model for an alteration zone which appears to be structurally controlled. The three-dimensional model of the Tertiary quartz monzonite intrusive indicates a relatively shallow, slightly elongate intrusion that continues to a depth of at least 1 km.
Sawyer, Robert F.; Cook, Kenneth L.
Gravity and ground magnetic surveys in the Monroe and Joseph KGRA's and surrounding region, South Central Utah
Regional gravity data were collected in portions of the Pavant Range, Tushar Mountains, northern Sevier Plateau, the Antelope Range, and throughout Sevier Valley approximately between the towns of Richfield and Junction, Utah. Additionally, detailed gravity and ground magnetic data were collected in the vicinity of hot springs in both the Monroe and Joseph Known Geothermal Resource Areas (KGRA's) and subsurface geologic models were constructed. The regional gravity data were terrain corrected out to a distance of 167 km from the station and 948 gravity station values were compiled into a complete Bouguer gravity anomaly map of the survey area. This map shows a strong correlation with most structural features mapped in the survey area. Four regional gravity profiles were modeled using two-dimensional formerd and inverse algorithms.
Halliday, M.E.; Cook, K.L.
Optimizing future imaging survey of galaxies to confront dark energy and modified gravity models
We consider the extent to which future imaging surveys of galaxies can distinguish between dark energy and modified gravity models for the origin of the cosmic acceleration. Dynamical dark energy models may have similar expansion rates as models of modified gravity, yet predict different growth of structure histories. We parameterize the cosmic expansion by the two parameters, $w_0$ and $w_a$, and the linear growth rate of density fluctuations by Linder's $\\gamma$, independently. Dark energy models generically predict $\\gamma \\approx 0.55$, while the DGP model $\\gamma \\approx 0.68$. To determine if future imaging surveys can constrain $\\gamma$ within 20 percent (or $\\Delta\\gamma<0.1$), we perform the Fisher matrix analysis for a weak lensing survey such as the on-going Hyper Suprime-Cam (HSC) project. Under the condition that the total observation time is fixed, we compute the Figure of Merit (FoM) as a function of the exposure time $\\texp$. We find that the tomography technique effectively improves the FoM, which has a broad peak around $\\texp\\simeq {\\rm several}\\sim 10$ minutes; a shallow and wide survey is preferred to constrain the $\\gamma$ parameter. While $\\Delta\\gamma < 0.1$ cannot be achieved by the HSC weak-lensing survey alone, one can improve the constraints by combining with a follow-up spectroscopic survey like WFMOS and/or future CMB observations.
Kazuhiro Yamamoto; David Parkinson; Takashi Hamana; Robert C. Nichol; Yasushi Suto
Modeling the Interaction between Cumulus Convection and Linear Gravity Waves Using a Limited-Domain Cloud System�Resolving Model
A limited-domain cloud system�resolving model (CSRM) is used to simulate the interaction between cumulus convection and two-dimensional linear gravity waves, a single horizontal wavenumber at a time. With a single horizontal wavenumber, soundings ...
Zhiming Kuang
Results of a detailed gravity survey in the Alamosa Area, Alamosa County, Colorado
A total of 322 stations, centered on the City of Alamosa, were surveyed with a gravimeter during September 1981. These data have shown the Alamosa horst to have an irregular top. This irregularity is thought to be caused by paleovalleys and/or down-dropped fault blocks within the Precambrian horst. The City of Alamosa lies directly over a local gravity low. Volcanic rocks within this low may contain a reservoir for geothermal fluids, as yet unsubstantiated by drilling. Thermal fluids are thought to enter the Alamosa area via aquifers from the west (San Juan Mountains) and/or from the Rio Grande Rift zone with the fluids rising along fractures within and bordering the horst. The most favorable drilling targets appear to be either near the center of the local gravity low or in the fracture zone at the edges of the inferred down-dropped fault blocks.
Mackelprang, C.E.
The Parameterised Post-Newtonian Limit of Bimetric Theories of Gravity
We consider the post-Newtonian limit of a general class of bimetric theories of gravity, in which both metrics are dynamical. The established parameterised post-Newtonian approach is followed as closely as possible, although new potentials are found that do not exist within the standard frame-work. It is found that these theories can evade solar system tests of post-Newtonian gravity remarkably well. We show that perturbations about Minkowski space in these theories contain both massless and massive degrees of freedom, and that in general there are two different types of massive mode, each with a different mass parameter. If both of these masses are sufficiently large then the predictions of the most general class of theories we consider are indistinguishable from those of general relativity, up to post-Newtonian order in a weak field, low velocity expansion. In the limit that the massive modes become massless, we find that these general theories do not exhibit a van Dam-Veltman-Zakharov-like discontinuity in their gamma parameter, although there are discontinuities in other post-Newtonian parameters as the massless limit is approached. This smooth behaviour in gamma is due to the discontinuities from each of the two different massive modes cancelling each other out. Such cancellations cannot occur in special cases with only one massive mode, such as the Isham-Salam-Strathdee theory.
Timothy Clifton; M�ximo Ba�ados; Constantinos Skordis
An Einstein-like theory of gravity with a non-newtonian weak-field limit
We propose a model describing Einstein gravity coupled to a scalar field with an exponential potential. We show that the weak-field limit of the model has static solutions given by a gravitational potential behaving for large distances as \\ln r . The Newtonian term GM/r appears only as subleading. Our model can be used to give a phenomenological explanation of the rotation curves of the galaxies without postulating the presence of dark matter. This can be achieved only by giving up at galactic scales Einstein equivalence principle.
Mariano Cadoni
Gravity survey of the Cove Fort-Sulphurdale KGRA and the North Mineral Mountains area, Millard and Beaver Counties, Utah. Technical report: Volume 77-4
During the summers of 1975 and 1976, a gravity survey was conducted in the Cove Fort-Sulphurdale KGRA and north Mineral Mountains area, Millard and Beaver Counties, Utah. The survey consisted of 671 gravity stations covering an area of about 1300 km/sup 2/, and included two orthogonal gravity profiles traversing the area. The gravity data are presented as a terrain-corrected Bouguer gravity anomaly map with a contour interval of 1 mgal and as an isometric three-dimensional gravity anomaly surface. Selected anomaly separation techniques were applied to the hand-digitized gravity data (at 1-km intervals on the Universal Transverse Mercator grid) in both the frequency and space domains, including Fourier decomposition, second vertical derivative, strike-filter, and polynomial fitting analysis, respectively.
Liouville gravity from Einstein gravity
We show that Liouville gravity arises as the limit of pure Einstein gravity in 2+epsilon dimensions as epsilon goes to zero, provided Newton's constant scales with epsilon. Our procedure - spherical reduction, dualization, limit, dualizing back - passes several consistency tests: geometric properties, interactions with matter and the Bekenstein-Hawking entropy are as expected from Einstein gravity.
D. Grumiller; R. Jackiw
Principal facts for a gravity survey of Wendel-Amedee Known Geothermal Resource Area, California
The observed gravity, theoretical gravity, free-air correction, Bouguer correction, and simple Bouguer anomaly are given for 29 station locations in the Wendel-Amedee known resource area, California. (WHK)
Peterson, D.L.; Hassemer, J.H.
Massive gravity from bimetric gravity
We discuss the subtle relationship between so-called massive gravity (that is, gravity incorporating a non-zero graviton mass) and bimetric gravity, focussing particularly on the manner in which massive gravity may be viewed as a suitable limit of bimetric gravity. The limiting procedure is more delicate than currently appreciated, and in particular, in a cosmological context can lead to an interesting interplay between the "background" and "foreground" metrics. The fact that in bimetric theories one always has two sets of metric equations of motion, one for each metric, continues to have an effect even in the massive gravity limit. Thus, solutions of bimetric gravity in the limit of vanishing kinetic term are also solutions of massive gravity, but the contrary statement is not necessarily true.
Baccetti, Valentina; Visser, Matt
Borehole gravity surveys in the Cretaceous-Tertiary Sagavanirktok Formation, Kuparuk River oil field, Alaska
Detailed borehole gravity surveys (sponsored by the US Department of Energy) were made in three wells in the Kuparuk River and westernmost Prudhoe Bay oil fields, Alaska from depths as shallow as 15 m to as great as 1,340 m through permafrost and underlying heavy oil bearing sandstones of the Sagavanirktok Formation. A subbituminous coal-bearing sequence and the stability field for methane hydrate occur partly within and partly below the permafrost zone, whose base, defined by the 0{degree}C isotherm, varies from 464 to 564 m. The surveys provided accurate, large-volume estimates of in-situ bulk density from which equivalent porosity was calculated using independent grain and pore-fluid density information. This density and porosity data helped to define the rock mass properties within the hydrate stability field and the thermal conductivity, seismic character, and compaction history of the permafrost. Bulk density of the unconsolidated to poorly consolidated sections ranges mostly from 1.9 to 2.3 g/cm{sup 3}. The shallow permafrost section appears to be slightly overcompacted in comparison to similar sedimentary sequences in nonpermafrost regions. The cause of this apparent overcompaction is unknown but may be due to freeze-thaw processes that have similarly affected sea floor and surficial deposits elsewhere in the Arctic. Fluctuations of bulk density appear to be controlled principally by (1) textural variations of the sediments, possibly exaggerated locally within the permafrost zone by excess ice, (2) presence or absence of carbonaceous material, and (3) type of pore-fluid (water-ice vs. water vs. hydrocarbons). As hypothetical models predict bulk-density is slightly lower opposite one interval of possible methane hydrate. Porosity may be as high as 40-45% for selected coarser grained units within the permafrost zone, and as high as 30-35% in a series of well sorted, heavy oil-bearing sandstones.
Beyer, L.A. (Geological Survey, Menlo Park, CA (USA))
Principal facts for a gravity survey of Baltazor Known Geothermal Resource Area, Nevada
The data presented are referenced to a gravity base station in Denio, Nevada at the Post Office, 50 meters south of the Oregon-Nevada State line, 1.6 meters south of the door in the southeast corner of the concrete porch, near the mailbox. Site is monumented with a ''USAF Gravity Station'' disc (A.C.I.C. reference number 2352-1). Base value is 979945.94.
Peterson, D.L.; Hoover, D.B.
Is nonrelativistic gravity possible?
We study nonrelativistic gravity using the Hamiltonian formalism. For the dynamics of general relativity (relativistic gravity) the formalism is well known and called the Arnowitt-Deser-Misner (ADM) formalism. We show that if the lapse function is constrained correctly, then nonrelativistic gravity is described by a consistent Hamiltonian system. Surprisingly, nonrelativistic gravity can have solutions identical to relativistic gravity ones. In particular, (anti-)de Sitter black holes of Einstein gravity and IR limit of Horava gravity are locally identical.
Kocharyan, A. A. [School of Mathematical Sciences, Monash University, Clayton 3800 (Australia)
The Stability of Dilute Plasmas with Thermal and Composition Gradients. I. The Slow Conduction Limit: Overstable Gravity Modes
We analyze the stability of a dilute plasma with thermal and composition gradients in the limit where conduction is slow compared to the dynamical timescale. We find necessary and sufficient conditions for stability when the background magnetic field is either parallel or perpendicular to the thermal and composition gradients that are parallel to the gravitational field. We provide approximate solutions for all the relevant modes involved, which are driven by gravity, conduction, and diffusion. We discuss the astrophysical implications of our findings for a representative galaxy cluster where helium has sedimented.
Pessah, Martin E
Detailed gravity and aeromagnetic surveys of the Cove Fort-Sulphurdale KGRA and vicinity, Millard and Beaver Counties, Utah. Topical report
A detailed gravity survey (comprising 231 stations over about 900 km/sup 2/) was made in the Cove Fort-Sulphurdale Known Geothermal Resource area (KGRA) and vicinity, Millard and Beaver counties, Utah to assist in the appraisal of the potential of this area as a geothermal resource. The survey reinforced the results and information obtained in the previous regional gravity surveys comprising 522 stations. The gravity data from about 700 stations were reduced and compiled as a terrain-corrected (out to 20 km) Bouguer gravity anomaly map with 1-mgal contour interval. In August 1975, an aeromagnetic survey was flown over part of the survey area at a constant barometric elevation of 12,000 ft (3660 m). These aeromagnetic data are used to supplement the interpretation of the gravity data. The aeromagnetic field intensity residual anomaly map and the second-order polynomial residual aeromagnetic map (obtained by removing a second-order polynomial surface) are presented with a 20-gamma contour interval. Two north-south profiles and one east-west profile were selected for magnetic interpretative modeling. The two north-south profiles were also stacked and averaged over 6-km-wide strips and modeled. The occurrences of hydrothermal alteration, hot spring deposits, and flowing hot springs coincide with inferred fault zones. No evidence of extensive alteration can be interpreted from the magnetic data.
Cook, K.L.; Serpa, L.F.; Pe, W.
Spherically symmetric solutions, Newton's Law, and the infrared limit {lambda}{yields}1 in covariant Horava-Lifshitz gravity
In this note we examine whether spherically symmetric solutions in covariant Horava-Lifshitz gravity can reproduce Newton's Law in the IR limit {lambda}{yields}1. We adopt the position that the auxiliary field A is independent of the space-time metric [J. Alexandre and P. Pasipoularides, Phys. Rev. D 83, 084030 (2011).][J. Greenwald, V. H. Satheeshkumar, and A. Wang, J. Cosmol. Astropart. Phys. 12 (2010) 007.], and we assume, as in [A. M. da Silva, Classical Quantum Gravity 28, 055011 (2011).], that {lambda} is a running coupling constant. We show that under these assumptions, spherically symmetric solutions fail to restore the standard Newtonian physics in the IR limit {lambda}{yields}1, unless {lambda} does not run, and has the fixed value {lambda}=1. Finally, we comment on the Horava and Melby-Thompson approach [P. Horava and C. M. Melby-Thompson, Phys. Rev. D 82, 064027 (2010).] in which A is assumed as a part of the space-time metric in the IR.
Alexandre, Jean [King's College London, Department of Physics, London WC2R 2LS (United Kingdom); Pasipoularides, Pavlos [Department of Physics, National Technical University of Athens, Zografou Campus GR 157 73, Athens (Greece)
Newtonian gravity in loop quantum gravity
We apply a recent argument of Verlinde to loop quantum gravity, to conclude that Newton's law of gravity emerges in an appropriate limit and setting. This is possible because the relationship between area and entropy is realized in loop quantum gravity when boundaries are imposed on a quantum spacetime.
Smolin, Lee
Principal facts for a gravity survey of the Double Hot Springs Known Geothermal Resource Area, Humboldt County, Nevada
During July 1977, forty-nine gravity stations were obtained in the Double Hot Springs Known Geothermal Resource Area and vicinity, northwestern Nevada. The gravity observations were made with a Worden gravimeter having a scale factor of about 0.5 milligal per division. No terrain corrections have been applied to these data. The earth tide correction was not used in drift reduction. The Geodetic Reference System 1967 formula (International Association of Geodesy, 1967) was used to compute theoretical gravity.
Peterson, D.L.; Kaufmann, H.E.
Principal facts for a gravity survey of the Gerlach Extension Known Geothermal Resource Area, Pershing County, Nevada
During July 1977, fifty-one gravity stations were obtained in the Gerlach Extension Known Geothermal Resource Area and vicinity, northwestern Nevada. The gravity observations were made with a Worden gravimeter having a scale factor of about 0.5 milligal per division. No terrain corrections have been applied to these data. The earth tide correction was not used in drift reduction. The Geodetic Reference System 1967 formula (International Association of Geodesy, 1967) was used to compute theoretical gravity. Observed gravity is referenced to a base station in Gerlach, Nevada, having a value based on the Potsdam System of 1930. A density of 2.67 g per cm/sup 3/ was used in computing the Bouguer anomaly.
Principal facts for a gravity survey of the Fly Ranch Extension Known Geothermal Resource Area, Pershing County, Nevada
During July 1977, forty-four gravity stations were obtained in the Fly Ranch Extension Known Geothermal Resource Area and vicinity, northwestern Nevada. The gravity observations were made with a Worden gravimeter having a scale factor of about 0.5 milligal per division. No terrain corrections have been applied to these data. The earth tide correction was not used in drift reduction. The Geodetic Reference System 1967 formula (International Association of Geodesy, 1967) was used to compute theoretical gravity. Observed gravity is referenced to a base station in Gerlach, Nevada, having a value based on the Potsdam System of 1930 (fig. 1). A density of 2.67 g per cm/sup 3/ was used in computing the Bouguer anomaly.
Low surface brightness galaxies rotation curves in the low energy limit of $R^n$ gravity : no need for dark matter?
We investigate the possibility that the observed flatness of the rotation curves of spiral galaxies is not an evidence for the existence of dark matter haloes, but rather a signal of the breakdown of General Relativity. To this aim, we consider power - law fourth order theories of gravity obtained by replacing the scalar curvature $R$ with $f(R) = f_0 R^n$ in the gravity Lagrangian. We show that, in the low energy limit, the gravitational potential generated by a pointlike source may be written as $\\Phi(r) \\propto r^{-1} \\left [ 1 + (r/r_c)^{\\beta} \\right ]$ with $\\beta$ a function of the slope $n$ of the gravity Lagrangian and $r_c$ a scalelength depending on the gravitating system properties. In order to apply the model to realistic systems, we compute the modified potential and the rotation curve for spherically symmetric and for thin disk mass distributions. It turns out that the potential is still asymptotically decreasing, but the corrected rotation curve, although not flat, is higher than the Newtonian one thus offering the possibility to fit rotation curves without dark matter. To test the viability of the model, we consider a sample of 15 low surface brightness (LSB) galaxies with combined HI and H$\\alpha$ measurements of the rotation curve extending in the putative dark matter dominated region. We find a very good agreement between the theoretical rotation curve and the data using only stellar disk and interstellar gas.
S. Capozziello; V. F. Cardone; A. - Troisi
A VOLUME-LIMITED PHOTOMETRIC SURVEY OF 114 {gamma} DORADUS CANDIDATES
We have carried out a photometric survey of a complete, volume-limited sample of {gamma} Doradus candidates. The sample was extracted from the Hipparcos catalog and consists of 114 stars with colors and absolute magnitudes within the range of known {gamma} Doradus stars and that also lie within a specified volume of 266,600 pc{sup 3}. We devoted one year of observing time with our T12 0.8 m automatic photometric telescope to acquire nightly observations of the complete sample of stars. From these survey observations, we identify 37 stars with intrinsic variability of 0.002 mag or more. Of these 37 variables, 8 have already been confirmed as {gamma} Doradus stars in our earlier papers; we scheduled the remaining 29 variables on our T3 0.4 m automatic telescope to acquire more intensive observations over the next two years. As promising new {gamma} Doradus candidates were identified from the photometry, we obtained complementary spectroscopic observations of each candidate with the Kitt Peak coude feed telescope. Analysis of our new photometric and spectroscopic data reveals 15 new {gamma} Doradus variables (and confirms two others), 8 new {delta} Scuti variables (and confirms one other), and 3 new variables with unresolved periodicity. Therefore, of the 114 {gamma} Doradus candidates in our volume-limited sample, we find 25 stars that are new or previously known {gamma} Doradus variables. This results in an incidence of 22% for {gamma} Doradus variability among candidate field stars for this volume of the solar neighborhood. The corresponding space density of {gamma} Doradus stars in this volume of space is 0.094 stars per 10{sup 3} pc{sup 3} or 94 stars per 10{sup 6} pc{sup 3}. We provide an updated list of 86 bright, confirmed, {gamma} Doradus field stars.
Henry, Gregory W.; Fekel, Francis C. [Center of Excellence in Information Systems, Tennessee State University, 3500 John A. Merritt Blvd., Box 9501, Nashville, TN 37209 (United States); Henry, Stephen M., E-mail: firstname.lastname@example.com, E-mail: firstname.lastname@example.com, E-mail: firstname.lastname@example.com [Department of Mathematical Sciences, Clemson University, O-110 Martin Hall, Box 340975, Clemson, SC 29634 (United States)
DOE Patents (OSTI)
A limiter with a specially contoured front face is provided. The front face of the limiter (the plasma-side face) is flat with a central indentation. In addition, the limiter shape is cylindrically symmetric so that the limiter can be rotated for greater heat distribution. This limiter shape accommodates the various power scrape-off distances lambda p, which depend on the parallel velocity, V/sub parallel/, of the impacting particles.
Cohen, S.A.; Hosea, J.C.; Timberlake, J.R.
Identifying Student Concepts of Gravity.
??This paper discusses a survey developed to investigate student concepts of "gravity" among AST 109 astronomy students and pre-service K-12 teachers. Survey questions were developed� (more)
Feeley, Roger Eastman
Introduction to Loop Quantum Gravity
The questions I have been asked during the 5th International School on Field Theory and Gravitation, have compelled me to give an account of the premises that I consider important for a beginner's approach to Loop Quantum Gravity. After a description of some general arguments and an introduction to the canonical theory of gravity, I review the background independent approach to quantum gravity, giving only a brief survey of Loop Quantum Gravity.
Mercuri, Simone
Simone Mercuri
A limiter with a specially contoured front face accommodates the various power scrape-off distances .lambda..sub.p, which depend on the parallel velocity, V.sub..parallel., of the impacting particles. The front face of the limiter (the plasma-side face) is flat with a central indentation. In addition, the limiter shape is cylindrically symmetric so that the limiter can be rotated for greater heat distribution.
Cohen, Samuel A. (Hopewell, NJ); Hosea, Joel C. (Princeton, NJ); Timberlake, John R. (Allentown, NJ)
Near-horizon limit of the charged BTZ black hole and AdS_2 quantum gravity
We show that the 3D charged Banados-Teitelboim-Zanelli (BTZ) black hole solution interpolates between two different 2D AdS spacetimes: a near-extremal, near-horizon AdS_2 geometry with constant dilaton and U(1) field and an asymptotic AdS_2 geometry with a linear dilaton. Thus, the charged BTZ black hole can be considered as interpolating between the two different formulations proposed until now for AdS_2 quantum gravity. In both cases the theory is the chiral half of a 2D CFT and describes, respectively, Brown-Hennaux-like boundary deformations and near-horizon excitations. The central charge c_as of the asymptotic CFT is determined by 3D Newton constant G and the AdS length l, c_as=3l/G, whereas that of the near-horizon CFT also depends on the U(1) charge Q, c_nh \\propto l Q/\\sqrt G.
Mariano Cadoni; Mohammad R. Setare
Gravity monitoring of CO2 movement during sequestration: Model studies
right. Figure 14: Surface gravity response (?Gal) for theAbsolute and relative gravity integration for high precision2003, Seafloor Micro-gravity Survey of the Sleipner CO 2
Gasperikova, E.
Massive Gravity
We review recent progress in massive gravity. We start by showing how different theories of massive gravity emerge from a higher-dimensional theory of general relativity, leading to the Dvali-Gabadadze-Porrati model, cascading gravity and ghost-free massive gravity. We then explore their theoretical and phenomenological consistency, proving the absence of Boulware-Deser ghosts and reviewing the Vainshtein mechanism and the cosmological solutions in these models. Finally we present alternative and related models of massive gravity such as new massive gravity, Lorentz-violating massive gravity and non-local massive gravity.
de Rham, Claudia
Claudia de Rham
Rapid gravity and gravity gradiometry terrain corrections via an adaptive quadtree mesh discretization
Rapid gravity and gravity gradiometry terrain corrections via an adaptive quadtree mesh discretization Kristofer Davis1,2 M. Andy Kass1 Yaoguo Li1 1 Center for Gravity, Electrical, and Magnetic Studies of gravity gradiometry surveys utilising an adaptive quadtree mesh discretization. The data- and terrain
The Extended GMRT Radio Halo Survey I: New upper limits on radio halos and mini-halos
A fraction of galaxy clusters host diffuse radio sources called radio halos, radio relics and mini-halos. We present the sample and first results from the Extended GMRT Radio Halo Survey (EGRHS)- an extension of the GMRT Radio Halo Survey (GRHS, Venturi et al. 2007, 2008). It is a systematic radio survey of galaxy clusters selected from the REFLEX and eBCS X-ray catalogs . Analysis of GMRT data at 610/ 235/ 325 MHz on 12 galaxy clusters are presented. We report the detection of a newly discovered mini-halo in the cluster RXJ1532.9+3021 at 610 MHz. A small scale relic (~200 kpc) is suspected in the cluster Z348. We do not detect cluster-scale diffuse emission in 11 clusters. Robust upper limits on the detection of radio halo of size of 1 Mpc are determined. We also present upper limits on the detections of mini-halos in a sub-sample of cool-core clusters. The upper limits for radio halos and mini-halos are plotted in the radio power- X-ray luminosity plane and the correlations are discussed. Diffuse extended e...
Kale, R; Giacintucci, S; Dallacasa, D; Cassano, R; Brunetti, G; Macario, G; Athreya, R
Higgs-induced spectroscopic shifts near strong gravity sources
We explore the consequences of the mass generation due to the Higgs field in strong gravity astrophysical environments. The vacuum expectation value of the Higgs field is predicted to depend on the curvature of spacetime, potentially giving rise to peculiar spectroscopic shifts, named hereafter 'Higgs shifts'. Higgs shifts could be searched through dedicated multiwavelength and multispecies surveys with high spatial and spectral resolution near strong gravity sources such as Sagittarius A* or broad searches for signals due to primordial black holes. The possible absence of Higgs shifts in these surveys should provide limits to the coupling between the Higgs particle and the curvature of spacetime, a topic of interest for a recently proposed Higgs-driven inflationary model. We discuss some conceptual issues regarding the coexistence between the Higgs mechanism and gravity, especially for their different handling of fundamental and composite particles.
Onofrio, Roberto [Dipartimento di Fisica 'Galileo Galilei', Universita di Padova, Via Marzolo 8, Padova 35131 (Italy) and ITAMP, Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, Massachusetts 02138 (United States)
Gravity in Gauge Mediation
We investigate O'Raifeartaigh-type models for F-term supersymmetry breaking in gauge mediation scenarios in the presence of gravity. It is pointed out that the vacuum structure of those models is such that in metastable vacua gravity mediation contribution to scalar masses is always suppressed to the level below 1 percent, almost sufficient for avoiding FCNC problem. Close to that limit, gravitino mass can be in the range 10-100 GeV, opening several interesting possibilities for gauge mediation models, including Giudice-Masiero mechanism for mu and Bmu generation. Gravity sector can include stabilized moduli.
Zygmunt Lalak; Stefan Pokorski; Krzysztof Turzynski
Entropic Gravity in Rindler Space
We show that Rindler horizons are entropic screens and gravity is an entropic force in Rindler space by deriving the Verlinde entropy formula from the focusing of light due to a mass close to the horizon. Consequently, gravity is also entropic in the near horizon regions of Schwarzschild and de Sitter space-times. In different limits, the entropic nature of gravity in Rindler space leads to the Bekenstein entropy bound and the uncertainty principle.
Halyo, Edi
Edi Halyo
Cascading gravity is ghost free
We perform a full perturbative stability analysis of the 6D cascading gravity model in the presence of 3-brane tension. We demonstrate that for sufficiently large tension on the (flat) 3-brane, there are no ghosts at the perturbative level, consistent with results that had previously only been obtained in a specific 5D decoupling limit. These results establish the cascading gravity framework as a consistent infrared modification of gravity.
Rham, Claudia de [Departement de Physique Theorique, Universite de Geneve, 24 Quai E. Ansermet, CH-1211 Geneve (Switzerland); Khoury, Justin [Center for Particle Cosmology, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6395 (United States); Tolley, Andrew J. [Perimeter Institute for Theoretical Physics, 31 Caroline St. N., Waterloo, ON, N2L 2Y5 (Canada)
Detection, size, measurement and structural analysis limits for the 2MASS, UKIDSS-LAS & VISTA VIKING surveys
The 2MASS, UKIDSS-LAS and VISTA VIKING surveys have all now observed the GAMA 9hr region in the $K_s$ band. Here we compare the detection rates, photometry, basic size measurements, and single-component GALFIT structural measurements for a sample of 37,591 galaxies. We explore the sensitivity limits where the data agree for a variety of issues including: detection, star-galaxy separation, photometric measurements, size and ellipticity measurements, and S\\'{e}rsic measurements. We find that 2MASS fails to detect at least 20% of the galaxy population within all magnitude bins, however for those that are detected we find photometry is robust ($\\pm$ 0.2 mag) to 14.7 AB mag and star-galaxy separation to 14.8 AB mag. For UKIDSS-LAS we find incompleteness starts to enter at a flux limit of 18.9 AB mag, star-galaxy separation is robust to 16.3 AB mag and structural measurements are robust to 17.7 AB mag. VISTA VIKING data is complete to approximately 20.0 AB mag and structural measurements appear robust to 18.8 AB ma...
Andrews, Stephen K; Driver, Simon P; Robotham, Aaron S G
Einstein Gravity from Conformal Gravity
We show that that four dimensional conformal gravity plus a simple Neumann boundary condition can be used to get the semiclassical (or tree level) wavefunction of the universe of four dimensional asymptotically de-Sitter or Euclidean anti-de Sitter spacetimes. This simple Neumann boundary condition selects the Einstein solution out of the more numerous solutions of conformal gravity. It thus removes the ghosts of conformal gravity from this computation. In the case of a five dimensional pure gravity theory with a positive cosmological constant we show that the late time superhorizon tree level probability measure, $|\\Psi [ g ]|^2$, for its four dimensional spatial slices is given by the action of Euclidean four dimensional conformal gravity.
Juan Maldacena
Gravity brake
A mechanical gravity brake that prevents hoisted loads within a shaft from free-falling when a loss of hoisting force occurs. A loss of hoist lifting force may occur in a number of situations, for example if a hoist cable were to break, the brakes were to fail on a winch, or the hoist mechanism itself were to fail. Under normal hoisting conditions, the gravity brake of the invention is subject to an upward lifting force from the hoist and a downward pulling force from a suspended load. If the lifting force should suddenly cease, the loss of differential forces on the gravity brake in free-fall is translated to extend a set of brakes against the walls of the shaft to stop the free fall descent of the gravity brake and attached load.
Lujan, Richard E. (Santa Fe, NM)
Gravity Waves in a Horizontal Shear Flow. Part II: Interaction between Gravity Waves and Potential Vorticity Perturbations
Gravity Waves in a Horizontal Shear Flow. Part II: Interaction between Gravity Waves and Potential perturbations and propagating internal gravity waves in a horizon- tally sheared zonal flow is investigated. In the strong stratification limit, an initial vorticity perturbation weakly excites two propagating gravity
Farrell, Brian F.
Lovelock gravity from entropic force
In this paper, we first generalize the formulation of entropic gravity to (n+1)-dimensional spacetime. Then, we propose an entropic origin for Gauss-Bonnet gravity and more general Lovelock gravity in arbitrary dimensions. As a result, we are able to derive Newton's law of gravitation as well as the corresponding Friedmann equations in these gravity theories. This procedure naturally leads to a derivation of the higher dimensional gravitational coupling constant of Friedmann/Einstein equation which is in complete agreement with the results obtained by comparing the weak field limit of Einstein equation with Poisson equation in higher dimensions. Our study shows that the approach presented here is powerful enough to derive the gravitational field equations in any gravity theory. PACS: 04.20.Cv, 04.50.-h, 04.70.Dy.
A. Sheykhi; H. Moradpour; N. Riazi
Understanding gravity
AdS/CFT correspondence provides a holographic duality between gravitational physics and gauge dynamics. What field theory configurations lend themselves to a good semi-classical description? Relevance: Making precise the nature of the holographic map Understanding the emergence of geometry. What are �legal � singularities in gravity (cosmic censorship)? Insight into new solutions. Motivation Conformal fluids Bulk geometry Horizons & entropy Conclusion
Mukund Rangamani
Gravity settling
Solids are separated from a liquid in a gravity settler provided with inclined solid intercepting surfaces to intercept the solid settling path to coalesce the solids and increase the settling rate. The intercepting surfaces are inverted V-shaped plates, each formed from first and second downwardly inclined upwardly curved intersecting conical sections having their apices at the vessel wall.
Davis, Hyman R. (Glenridge, NJ); Long, R. H. (Morristown, NJ); Simone, A. A. (Dover, NJ)
Beating the confusion limit: The necessity of high angular resolution for probing the physics of Sagittarius A* and its environment: Opportunities for LINC-NIRVANA (LBT), GRAVITY (VLTI) and and METIS (E-ELT)
The super-massive 4 million solar mass black hole (SMBH) SgrA* shows variable emission from the millimeter to the X-ray domain. A detailed analysis of the infrared light curves allows us to address the accretion phenomenon in a statistical way. The analysis shows that the near-infrared flux density excursions are dominated by a single state power law, with the low states of SgrA* limited by confusion through the unresolved stellar background. We show that for 8-10m class telescopes blending effects along the line of sight will result in artificial compact star-like objects of 0.5-1 mJy that last for about 3-4 years. We discuss how the imaging capabilities of GRAVITY at the VLTI, LINC-NIRVANA at the LBT and METIS at the E-ELT will contribute to the investigation of the low variability states of SgrA*.
Eckart, A; Witzel, G; Straubmeier, C; Shahzamanian, B; Valencia-S., M; Garcia-Marin, M; Horrobin, M; Moser, L; Zuther, J; Fischer, S; Rauch, C; Rost, S; Iserlohe, C; Yazici, S; Smajic, S; Wiest, M; Araujo-Hauck, C; Wank, I
Born-Infeld gravity in three dimensions
In this paper we explore different aspects of three dimensional Born-Infeld as well as Born-Infeld-Chern-Simons gravity. We show that the models have anti-de Sitter and anti-de Sitter wave vacuum solutions. Moreover, we observe that although Born-Infeld-Chern-Simons gravity admits a logarithmic solution, Born-Infeld gravity does not, though it has a limiting logarithmic solution as we approach the critical point.
Alishahiha, Mohsen [School of physics, Institute for Research in Fundamental Sciences (IPM), P.O. Box 19395-5531, Tehran (Iran, Islamic Republic of); Naseh, Ali [School of physics, Institute for Research in Fundamental Sciences (IPM), P.O. Box 19395-5531, Tehran (Iran, Islamic Republic of); Department of Physics, Sharif University of Technology, P.O. Box 11365-9161, Tehran (Iran, Islamic Republic of); Soltanpanahi, Hesam [School of physics, Institute for Research in Fundamental Sciences (IPM), P.O. Box 19395-5531, Tehran (Iran, Islamic Republic of); School of Physics and Centre for Theoretical Physics, University of the Witwatersrand, WITS 2050 Johannesburg (South Africa)
Intrusive gravity currents
The front speed of intrusive gravity currents. J. FluidP.F. Linden. Intrusive gravity currents. J. Fluid Mechanics,of mesoscale variability of gravity waves. Part II: Frontal,
Hang, Alice Thanh
more restrictive context of Einstein's theory of gravity.6782 TORSION AND QUANTUM GRAVITY Andrevr J, Him son Lawrencetorsion in conventional gravity cou~d in fact be dynamicaL A
Hanson, Andrew J.
Cosmological Acceleration: Dark Energy or Modified Gravity?
We review the evidence for recently accelerating cosmological expansion or "dark energy", either a negative pressure constituent in General Relativity (Dark Energy) or modified gravity (Dark Gravity), without any Dark Energy constituent. If constituent Dark Energy does not exist, so that our universe is now dominated by pressure-free matter, Einstein gravity must be modified at low curvature. The vacuum symmetry of any Robertson-Walker universe then characterizes Dark Gravity as low- or high-curvature modifications of Einstein gravity. The dynamics of either kind of "dark energy" cannot be derived from the homogeneous expansion alone, but requires also observing the growth of inhomogeneities. Present and projected observations are all consistent with a small fine tuned cosmological constant, with nearly static Dark Energy, or with gravity modified at cosmological scales. The growth of cosmological fluctuations will potentially distinguish static "dark energy" from dynamic "dark energy" with equation of state $w(z)$ either changing rapidly or tracking the background matter. But to cosmologically distinguish $\\Lambda$CDM from modified gravity will require a weak lensing shear survey more ambitious than any now projected. Dvali-Gabadadze-Porrati modifications of Einstein gravity may also be detected in refined bservations in the solar system or at the intermediate Vainstein scale. Dark Energy's epicyclic character, failure to explain the original Cosmic Coincidence ("Why now?") without fine tuning, inaccessibility to laboratory or solar system tests, along with braneworld theories, now motivate future precision solar system, Vainstein-scale and cosmological-scale studies of Dark Gravity.
Sidney Bludman
Deformed Einstein Gravity
We introduce the necessary concepts for an algebraic construction of a gravity theory on noncommutative spaces. The ??deformed diffeomorphisms are studied and a tensor calculus is defined. This leads to a deformed Einstein?Hilbert action which is invariant with respect to deformed diffeomorphisms. The dynamical variable is the vierbein field. The deformed action is a deformation of the usual Einstein?Hilbert action and reduces to it in the limit where the noncommutativity vanishes. This contribution is based on joint work with P. Aschieri
Frank Meyer
Overlap Fermion in External Gravity
On a lattice, we construct an overlap Dirac operator which describes the propagation of a Dirac fermion in external gravity. The local Lorentz symmetry is manifestly realized as a lattice gauge symmetry, while the general coordinate invariance is expected to be restored only in the continuum limit. The lattice index density in the presence of a gravitational field is calculated.
Hiroto So; Masashi Hayakawa; Hiroshi Suzuki
Effect of Nonlinearity on Atmospheric Gravity Waves
The weakly nonlinear limit of two-dimensional gravity waves in an incompressible, inviscid and stably stratified atmosphere is studied. The three-wave resonant interaction theory indicates an energy cascade from a vertically propagating wave (...
Mostafa M. Ibrahim
Generation of Turbulence by Atmospheric Gravity Waves
The standard current criterion for the generation of turbulence by atmospheric gravity waves and for the associated limitation on wave growth is based upon the standard criterion for static instability of the unperturbed atmosphere, namely, that ...
Colin O. Hines
Chiral gravity, log gravity, and extremal CFT
We show that the linearization of all exact solutions of classical chiral gravity around the AdS{sub 3} vacuum have positive energy. Nonchiral and negative-energy solutions of the linearized equations are infrared divergent at second order, and so are removed from the spectrum. In other words, chirality is confined and the equations of motion have linearization instabilities. We prove that the only stationary, axially symmetric solutions of chiral gravity are BTZ black holes, which have positive energy. It is further shown that classical log gravity--the theory with logarithmically relaxed boundary conditions--has finite asymptotic symmetry generators but is not chiral and hence may be dual at the quantum level to a logarithmic conformal field theories (CFT). Moreover we show that log gravity contains chiral gravity within it as a decoupled charge superselection sector. We formally evaluate the Euclidean sum over geometries of chiral gravity and show that it gives precisely the holomorphic extremal CFT partition function. The modular invariance and integrality of the expansion coefficients of this partition function are consistent with the existence of an exact quantum theory of chiral gravity. We argue that the problem of quantizing chiral gravity is the holographic dual of the problem of constructing an extremal CFT, while quantizing log gravity is dual to the problem of constructing a logarithmic extremal CFT.
Maloney, Alexander [Physics Department, McGill University, Montreal, QC H3A 2T8 (Canada); Song Wei [Key Laboratory of Frontiers in Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing, 100190 (China); Center for the Fundamental Laws of Nature Jefferson Physical Laboratory, Harvard University, Cambridge, Massachusetts 02138 (United States); Strominger, Andrew [Center for the Fundamental Laws of Nature Jefferson Physical Laboratory, Harvard University, Cambridge, Massachusetts 02138 (United States)
Chiral Gravity, Log Gravity and Extremal CFT
We show that the linearization of all exact solutions of classical chiral gravity around the AdS3 vacuum have positive energy. Non-chiral and negative-energy solutions of the linearized equations are infrared divergent at second order, and so are removed from the spectrum. In other words, chirality is confined and the equations of motion have linearization instabilities. We prove that the only stationary, axially symmetric solutions of chiral gravity are BTZ black holes, which have positive energy. It is further shown that classical log gravity-- the theory with logarithmically relaxed boundary conditions --has finite asymptotic symmetry generators but is not chiral and hence may be dual at the quantum level to a logarithmic CFT. Moreover we show that log gravity contains chiral gravity within it as a decoupled charge superselection sector. We normally evaluate the Euclidean sum over geometries of chiral gravity and show that it gives precisely the holomorphic extremal CFT partition function. The modular invariance and integrality of the expansion coefficients of this partition function are consistent with the existence of an exact quantum theory of chiral gravity. We argue that the problem of quantizing chiral gravity is the holographic dual of the problem of constructing an extremal CFT, while quantizing log gravity is dual to the problem of constructing a logarithmic extremal CFT.
Alexander Maloney; Wei Song; Andrew Strominger
A new approach to quantum gravity
A new idea of quantum gravity is developed based on Gravitational Complementary Principle. This principle states that gravity has dual complement features: The quantum and classical aspects of gravity are complement and absolutely separated by the planck length into planckian and over-planckian domains, respectively. The classical Einstein equations are correct at the fundamental level at over-planckian domain and general relativity is not a low energy limit of a more fundamental theory. The quantum gravity is totally confined to the planckian domain with a new kind of ultra-short range interaction, mediated by massive (Planck mass) particles, through the virtual microscopic wormholes of the Planck scale with action �h. There is no room for gravitons or extra dimensions in ?e-mail:email@example.com 1this scenario. It is shown that the hierarchy problem can solve the cosmological constant problem via this new quantum gravity. 2 1
F. Darabi
Scattering in Topologically Massive Gravity, Chiral Gravity and the corresponding Anyon-Anyon Potential Energy
We compute the tree-level scattering amplitude between two covariantly conserved sources in generic Cosmological Topologically Massive Gravity augmented with a Fierz-Pauli term that has three massive degrees of freedom. We consider the Chiral Gravity limit in the anti-de Sitter space as well as the limit of Flat-Space Chiral Gravity. We show that Chiral Gravity cannot be unitarily deformed with a Fierz-Pauli mass. We calculate the non-relativistic potential energy between two point-like spinning sources. In addition to the expected mass-mass and spin-spin interactions, there are mass-spin interactions due to the presence of the gravitational Chern-Simons term which induces spin for any massive object and turns it to an anyon. We also show that the tree-level scattering is trivial for the Flat-Space Chiral Gravity.
Dengiz, Suat; Tekin, Bayram
Towards noncommutative gravity
In this short article accessible for non-experts I discuss possible ways of constructing a non-commutative gravity paying special attention to possibilities of realizing the full diffeomorphism symmetry and to relations with 2D gravities.
D. V. Vassilevich
Heigth and Gravity
NLE Websites -- All DOE Office Websites (Extended Search)
Heigth and Gravity Name: Evan Location: NA Country: NA Date: NA Question: Does gravity effect a person's height? How does it? Would people with back problems benefit from time...
Repetitive precision gravity studies at the Cerro Prieto and Heber geothermal fields
To study subsidence and mass removal, a precise gravity network was established on 60 permanent monuments in the Cerro Prieto geothermal field in early 1978, and repeated annually through early 1981; the survey was tied to two bedrock sites outside the limits of the current production zone. The looping technique of station occupation was utilized, in which occupation of the base was followed by occupation of several stations, followed by a return to the base. Use of two LaCoste and Romberg gravity meters, and replication of values within loops as well as entire loops, enhanced precision such that the median standard deviations of the base-to-station differences, reduced to observed gravity values, ranged from 7 to 15 microgals for individual surveys. The smaller values were obtained as field and data reduction techniques were improved and experience was gained. A similar survey was initiated in the Heber area just north of the Mexican border in early 1980. It too was established on permanent monuments, was tied to bedrock stations outside the geothermal area, and used multiple repetitions of values with two meters to achieve high precision.
Grannell, R.B.
Motion in Quantum Gravity
We tackle the question of motion in Quantum Gravity: what does motion mean at the Planck scale? Although we are still far from a complete answer we consider here a toy model in which the problem can be formulated and resolved precisely. The setting of the toy model is three dimensional Euclidean gravity. Before studying the model in detail, we argue that Loop Quantum Gravity may provide a very useful approach when discussing the question of motion in Quantum Gravity.
Karim Noui
Stephen Hawking Quantum Gravity
Stephen Hawking and Quantum Gravity Matt Visser Physics Department Washington University Saint Louis USA Science Saturdays 4 Nov 2000 #12; Stephen Hawking and Quantum Gravity Abstract: Through research, Stephen Hawking has captured a place in the popular imagina- tion. Quantum gravity in its various
Visser, Matt
Quantum Physics Einstein's Gravity
Quantum Physics confronts Einstein's Gravity Matt Visser Physics Department Washington University Saint Louis USA Science Saturdays 13 October 2001 #12; Quantum Physics confronts Einstein's Gravity and with Einstein's theory of gravity (the general relativity) is still the single biggest theoretical problem
Ultraviolet Complete Quantum Gravity
An ultraviolet complete (UV) quantum gravity theory is formulated in which vertex functions in Feynman graphs are entire functions and the propagating gravitons are described by local, causal propagators. A scalar-tensor action describes classical gravity theory. The cosmological constant problem is investigated in the context of the UV complete quantum gravity.
Moffat, J W
Quantum Gravity at the LHC
It has recently been shown that if there is a large hidden sector in Nature, the scale of quantum gravity could be much lower than traditionally expected. We study the production of massless gravitons at the LHC and compare our results to those obtained in extra dimensional models. The signature in both cases is missing energy plus jets. In case of non observation, the LHC could be used to put the tightest limit to date on the value of the Planck mass.
Xavier Calmet; Priscila de Aquino
The Universe Adventure - Gravity
Gravity: The Main Attraction Gravity: The Main Attraction Gravity Acts on All Matter Gravity's effect is apparent even at the largest scales: just as gravity keeps the Earth orbiting the sun, it holds these two irregular galaxies M32 and M110 in orbit around the larger Andromeda galaxy. In the late 1600s, the English mathematician Sir Isaac Newton gave the first scientific description of gravitation. Gravity is an attractive force existing between any two objects that have mass, causing them to accelerate towards each other. It is the weakest of the four fundamental forces but can act over great distances and is responsible for the formation of planets, stars, galaxies, and even larger scale structures such as groups and superclusters. Gravity is also the force that governs the motion of
Quantization of Emergent Gravity
Emergent gravity is based on a novel form of the equivalence principle known as the Darboux theorem or the Moser lemma in symplectic geometry stating that the electromagnetic force can always be eliminated by a local coordinate transformation as far as spacetime admits a symplectic structure, in other words, a microscopic spacetime becomes noncommutative (NC). If gravity emerges from U(1) gauge theory on NC spacetime, this picture of emergent gravity suggests a completely new quantization scheme where quantum gravity is defined by quantizing spacetime itself, leading to a dynamical NC spacetime. Therefore the quantization of emergent gravity is radically different from the conventional approach trying to quantize a phase space of metric fields. This approach for quantum gravity allows a background independent formulation where spacetime as well as matter fields is equally emergent from a universal vacuum of quantum gravity.
Hyun Seok Yang
A gravity model for the Coso geothermal area, California | Open Energy
gravity model for the Coso geothermal area, California gravity model for the Coso geothermal area, California Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Conference Proceedings: A gravity model for the Coso geothermal area, California Details Activities (1) Areas (1) Regions (0) Abstract: Two- and three-dimensional gravity modeling was done using gridded Bouguer gravity data covering a 45 x 45 km region over the Coso geothermal area in an effort to identify features related to the heat source and to seek possible evidence for an underlying magma chamber. Isostatic and terrain corrected Bouguer gravity data for about 1300 gravity stations were obtained from the US Geological Survey. After the data were checked, the gravity values were gridded at 1 km centers for the area of interest centered on the Coso volcanic field. Most of the gravity
Category:Gravity Techniques | Open Energy Information
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Solar System experiments do not yet veto modified gravity models
The dynamical equivalence between modified and scalar-tensor gravity theories is revisited and it is concluded that it breaks down in the limit to general relativity. A gauge-independent analysis of cosmological perturbations in both classes of theories lends independent support to this conclusion. As a consequence, the PPN formalism of scalar-tensor gravity and Solar System experiments do not veto modified gravity, as previously thought.
Valerio Faraoni
Lectures on loop gravity
This is the first version of the introductory lectures on loop quantum gravity that I will give at the quantum gravity school in Zakopane. The theory is presented in self-contained form, without emphasis on its derivation from classical general relativity. Dynamics is given in the covariant form. The approximations needed to compute physical quantities are discussed. Some applications are described, including the recent derivation of de Sitter cosmology from full quantum gravity.
Rovelli, Carlo
Dark gravity and cosmology
The previous version of this article was a first attempt to confront the Dark Gravity theory to cosmological data. However, more recent developments lead to the conclusion that the cosmological principle is probably not valid in Dark Gravity so that this kind of analysis is at best very premature. A more recent and living review of the Dark Gravity theory can be found in gr-qc/0610079
F. Henry-Couannier; A. Tilquin; C. Tao; A. Ealet
Is Gravity an Interaction?
We consider a possibility that gravity is not an interaction but a manifestation of a symmetry based on a Galois field.
Felix M. Lev
Gold Standard Gravity ?�
This paper provides striking confirmation of the restrictions of the structural gravity model of trade. Structural forces predicted by theory explain 95 % of the variation of the fixed effects used to control for them in the recent gravity literature, fixed effects that in principle could reflect other forces. This validation opens avenues to inferring unobserved sectoral activity and multilateral resistance variables by equating fixed effects with structural gravity counterparts. Our findings also provide important validation of a host of general equilibrium comparative static exercises based on the structural gravity model.
James E. Anderson; Yoto V. Yotov; Dave Donaldson; Keith Head; Michael Waugh; We Arthur Lewbel
Direct-Current Resistivity Survey At Lightning Dock Area (Warpinski...
drilling a deep test well, additional geophysical work has been completed including gravity, resistivity, and airborne magnetic surveys. Several new seismic profiles are planned...
Comment on "A limit on the variation of the speed of light arising from quantum gravity effects" aka "Testing Einstein's special relativity with Fermi's short hard gamma-ray burst GRB090510"
Recently the Fermi GBM and LAT Collaborations reported their new observational data disfavoring quite a number of the quantum gravity theories, including the one suggesting the nonlinear (logarithmic) modification of a quantum wave equation. We show that the latter is still far from being ruled out: it is not only able to explain the new data but also its phenomenological implications turn out to be more vast (and more interesting) than one expected before.
Konstantin G. Zloshchastiev
Quantum gravity on the lattice
the Conference Quantum Gravity: Challenges and Perspectives.divergences in quantum gravity. In: Hawking, S.W. , Israel,f ) V n?1 ( f ) = Quantum gravity on the lattice Similarly,
Hamber, Herbert W.
Gauge/Gravity Duality (Gauge Gravity Duality)
Gauge theories, which describe the particle interactions, are well understood, while quantum gravity leads to many puzzles. Remarkably, in recent years we have learned that these are actually dual, the same system written in different variables. On the one hand, this provides our most precise description of quantum gravity, resolves some long-standing paradoxes, and points to new principles. On the other, it gives a new perspective on strong interactions, with surprising connections to other areas of physics. I describe these ideas, and discuss current and future directions.
Polchinski, Joseph (Kavli Institute for Theoretical Physics)
Particle Dynamics And Emergent Gravity
The emergent gravity proposal is examined within the framework of noncommutative QED/gravity correspondence from particle dynamics point of view.
Amir H. Fatollahi
We apply a von Zeipel gravity darkening model to corotating binaries to obtain a simple, analytical expression for the emergent radiative flux from a tidally distorted primary orbiting a point-mass secondary. We adopt a simple Roche model to determine the envelope structure of the primary, assumed massive and centrally condensed, and use the results to calculate the flux. As for single rotating stars, gravity darkening reduces the flux along the stellar equator of the primary, but, unlike for rotating stars, we find that gravity brightening enhances the flux in a region around the stellar poles. We identify a critical limiting separation beyond which hydrostatic equilibrium no longer is possible, whereby the flux vanishes at the point on the stellar equator of the primary facing the companion. For equal-mass binaries, the total luminosity is reduced by about 13% when this limiting separation is reached.
White, Helen E.; Baumgarte, Thomas W. [Department of Physics and Astronomy, Bowdoin College, Brunswick, ME 04011 (United States); Shapiro, Stuart L. [Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL 61801 (United States)
Energy extraction and particle acceleration around a rotating black hole in Horava-Lifshitz gravity
Energy extraction and particle acceleration around a rotating black hole in Horava-Lifshitz gravity-Lifshitz gravity is studied. The strong dependence of the extracted energy from the special range of parameters that the fundamental parameter of the Horava-Lifshitz gravity can impose a limitation on the energy of the accelerating
Probability around the Quantum Gravity. Part 1: Planar Pure Gravity
Probability around the Quantum Gravity. Part 1: Planar Pure Gravity V.A.Malyshev \\Lambda September 17, 1998 Abstract In this paper we study stochastic dynamics which leaves quantum gravity equilibrium science and biology. At the same time the paper can serve an intro duction to quantum gravity
Reflection Survey At Under Steamboat Springs Area (Warpinski...
of 2000, (2) a micro-seismic survey run from November 2000 to April 200 1, and (3) a gravity survey conducted in April and May 2001. The 3-D surface seismic data are still being...
Status of Matter-Gravity Couplings in the SME
Constraints on Lorentz violation in matter-gravity couplings are summarized along with existing proposals to obtain sensitivities that exceed current limits by up to 11 orders of magnitude.
Tasson, Jay D
Toroidal solutions in Horava Gravity
Recently a new four-dimensional non relativistic renormalizable theory of gravity was proposed by Horava. This gravity reduces to Einstein gravity at large distances. In this paper by using the new action for gravity we present different toroidal solutions to the equations of motion. Our solutions describe the near horizon geometry with slow rotating parameter.
Ahmad Ghodsi
Equivalence between therm and gravity
We introduce the notion of thermal entropy density, and first demonstrated that there exists an equivalence between therm and gravity without depending on the definition of temperature or horizon. This equivalence indicates that gravity possesses thermal features, or, therm possesses effects of gravity. This may shed light on the nature of gravity.
Yang, Rong-Jia
Gravity and the quantum potential
We review some material connecting gravity and the quantum potential and provide a few new observations.
Robert Carroll
Solar system constraints on R$^n$ gravity
Recently, gravitational microlensing has been investigated in the framework of the weak field limit of fourth order gravity theory. However, solar system data (i.e. planetary periods and light bending) can be used to put strong constraints on the parameters of this class of gravity theories. We find that these parameters must be very close to those corresponding to the Newtonian limit of the theory.
A. F. Zakharov; A. A. Nucita; F. De Paolis; G. Ingrosso
Interaction among potential vorticity perturbations and propagating internal gravity waves in a horizontally sheared zonal flow is investigated. In the strong stratification limit, an initial vorticity perturbation weakly excites two propagating ...
Nikolaos A. Bakas; Brian F. Farrell
Gravity Waves from Thunderstorms
Gravity waves generated by severe thunderstorms in the eastern Ohio-Pennsylvania area were recorded by an array of microbarovariographs at Palisades, New York and by standard microbarographs across northeastern United States. The waves were ...
Nambath K. Balachandran
Why gravity is fundamental
It is argued that the existence of a minimum size of spacetime may imply the fundamental existence of gravity as a geometric property of spacetime described by general relativity.
Shan Gao
Causal Newton Gravity Law
The equations of the relativistic causal Newton gravity law for the planets of the solar system are studied in the approximation when the Sun rests at the coordinates origin and the planets do not iteract between each other.
Yury M. Zinoviev
Exercise in artificial gravity
Artificial gravity provided by short radius centrifugation is considered a promising countermeasure to the deleterious physiological effects of microgravity during long-duration space flight. We investigated the feasibility ...
Edmonds, Jessica Leigh
Dog Center of Gravity
Dog Center of Gravity Name: Dania Status: Student Grade: 9-12 Location: AZ Country: USA Date: NA Question: Currently in physics we are working with projectile motion. I am...
Gao, Sheldon
Quantum gravity effects in the Kerr spacetime
We analyze the impact of the leading quantum gravity effects on the properties of black holes with nonzero angular momentum by performing a suitable renormalization group improvement of the classical Kerr metric within quantum Einstein gravity. In particular, we explore the structure of the horizons, the ergosphere, and the static limit surfaces as well as the phase space available for the Penrose process. The positivity properties of the effective vacuum energy-momentum tensor are also discussed and the 'dressing' of the black hole's mass and angular momentum are investigated by computing the corresponding Komar integrals. The pertinent Smarr formula turns out to retain its classical form. As for their thermodynamical properties, a modified first law of black-hole thermodynamics is found to be satisfied by the improved black holes (to second order in the angular momentum); the corresponding Bekenstein-Hawking temperature is not proportional to the surface gravity.
Reuter, M. [Institute of Physics, University of Mainz, Staudingerweg 7, D-55099 Mainz (Germany); Tuiran, E. [Departamento de Fisica, Universidad del Norte, Km 5 via a Puerto Colombia, AA-1569 Barranquilla (Colombia)
Interaction among potential vorticity perturbations and propagating internal gravity waves in a horizontally sheared zonal flow is investigated. In the strong stratification limit, an initial vorticity perturbation weakly excites two propagating gravity waves while the density component of the potential vorticity perturbation is significantly amplified, potentially leading to convective collapse. If stratification is sufficiently weak, a strong coupling between vorticity perturbations and gravity waves is found and spontaneous gravity wave generation occurs. This coupling can be traced to the nonnormal interaction between the potential vorticity and gravity wave manifolds in the weak stratification limit. Vorticity perturbations amplify in energy due to downgradient Reynolds stress when their phase lines tilt against the shear and the large growth attained is transferred to propagating gravity waves. When the flow geometry is such that the excited gravity waves are confined in the vicinity of the vorticity perturbation by their trapping levels, an overall convective collapse of this region can be anticipated. On the other hand, when the flow geometry permits wave propagation, significant gravity wave emission occurs. 1.
Nikolaos A. Bakas; Brian; F. Farrell
Gravity-driven intrusions in stratified fluids
5.5.1 Five interleaving interfacial gravity currents 5.5.2Ten interleaving interfacial gravity currents . 5.6partial- depth intrusive gravity currents,� Atmosphere -
Maurer, Benjamin Dudley
A Survey of z~6 Quasars in the SDSS Deep Stripe: I. a Flux-Limited Sample at z_{AB}<21
We present the discovery of five quasars at z~6 selected from 260 deg^2 of the Sloan Digital Sky Survey (SDSS) southern survey, a deep imaging survey obtained by repeatedly scanning a stripe along the Celestial Equator. The five quasars with 20=6.0 and =-25.8 is (5.0+/-2.1) x 10^{-9} Mpc^{-3} mag^{-1}. We model the bright-end quasar luminosity function (QLF) at z~6 as a power law Phi(L_{1450}) \\propto L_{1450}^{beta}. The slope beta calculated from a combination of our sample and the luminous SDSS quasar sample is -3.1+/-0.4, significantly steeper than the slope of the QLF at z~4. Based on the derived QLF, we find that the quasar/AGN population cannot provide enough photons to ionize the intergalactic medium (IGM) at z~6 unless the IGM is very homogeneous and the luminosity (L*_{1450}) at which the QLF power law breaks is very low.
Linhua Jiang; Xiaohui Fan; James Annis; Robert H. Becker; Richard L. White; Kuenley Chiu; Huan Lin; Robert H. Lupton; Gordon T. Richards; Michael A. Strauss; Sebastian Jester; Donald P. Schneider
Non-trivial 2+1-Dimensional Gravity
We analyze 2+1-dimensional gravity in the framework of quantum gauge theory. We find that Einstein gravity has a trivial physical subspace which reflects the fact that the classical solution in empty space is flat. Therefore we study massive gravity which is not trivial. In the limit of vanishing graviton mass we obtain a non-trivial massless theory different from Einstein gravity. We derive the interaction from descent equations and obtain the cosmological topologically massive gravity. However, in addition to Einstein and Chern-Simons coupling we need coupling to fermionic ghost and anti-ghost fields and to a vector-graviton field with the same mass as the graviton.
D. R. Grigore; G. Scharf
Exploring Gravity and Gravitational Wave Dynamics Part II: Gravity Models
The need for a new gravity model may explain anomalous behavior exhibited by several recent experiments described in Part I. Although Newtonian gravity is adequate for predicting the motion of celestial bodies
P. A. Murad
Evaluating catchment-scale hydrological modeling by means of terrestrial gravity observations
through an old locomotive boiler full of sand at the dam site and piped by gravity to cisterns (USGS 1980; Aerometric Surveys 2007). The Waterworks site, which was gravity fed from the dam, lies Trancas Bridge. Courtesy napa County recorder's office. #12;SAnFrAnCiSCoESTuAryinSTiTuTE napa river Dam
Troch, Peter
Glossary API Gravity: An
Gasoline and Diesel Fuel Update (EIA)
5 60 60 131 5 . . The higher the API gravity, the lighter the compound. Light crudes generally exceed 38 degrees API and heavy crudes are commonly labeled as all crudes with an API gravity of 22 degrees or below. Intermediate crudes fall in the range of 22 degrees to 38 degrees API gravity. ASTM: American Society for Testing and Materials. Aviation Gasoline (Finished): A complex mixture of relatively volatile hydrocarbons with or without small quantities of additives, blended to form a fuel suitable for use in aviation reciprocating engines. Fuel specifi- cations are provided in ASTM Specification D 910 and Military Specification MIL-G-5572. Note: Data on blending components are not counted in data on fin- ished aviation gasoline. Barrel: A volumetric unit of measure for crude oil and petroleum products equivalent to 42 U.S. gallons. Bulk Sales: Wholesale sales of gasoline in individual
60 60 1315 . . The higher the API gravity, the lighter the compound. Light crudes generally exceed 38 degrees API and heavy crudes are commonly labeled as all crudes with an API gravity of 22 degrees or below. Intermediate crudes fall in the range of 22 degrees to 38 degrees API gravity. ASTM: American Society for Testing and Materials. Aviation Gasoline (Finished): A complex mixture of relatively volatile hydrocarbons with or without small quantities of additives, blended to form a fuel suitable for use in aviation reciprocating engines. Fuel specifi- cations are provided in ASTM Specification D 910 and Military Specification MIL-G-5572. Note: Data on blending components are not counted in data on fin- ished aviation gasoline. Barrel: A volumetric unit of measure for crude oil and petroleum products equivalent to 42 U.S. gallons. Bulk Sales: Wholesale sales of gasoline in individual
Macroscopic quantization of gravity
The moon is receding from earth at an average rate of 3.8 cm/yr [6][7][9][12].This anomaly cannot be attributed to the well-known tidal exchange of angular momentum between earth and moon [8]. A secular change in the astronomical unit AU is definitely a concern, it is reportedly increasing by about 15 cm/yr [9][10], in this letter; the concept of macroscopic quantization of gravity is introduced to account for these anomalies on theoretical basis. Interestingly, it was found useful in measuring the speed of gravity! What is more interesting is the fact that this concept is based on solid well known classical physics with no modifications to any standard model. It was found that the speed of gravity cg is in the range 10^4 c < cg < 10^5 c.
M. Y. Amin
Euler Chern Simons Gravity from Lovelock Born Infeld Gravity
In the context of a gauge theoretical formulation, higher dimensional gravity invariant under the AdS group is dimensionally reduced to Euler-Chern-Simons gravity. The dimensional reduction procedure of Grignani-Nardelli [Phys. Lett. B 300, 38 (1993)] is generalized so as to permit reducing D-dimensional Lanczos Lovelock gravity to d=D-1 dimensions.
Fernando Izaurieta; Eduardo Rodriguez; Patricio Salgado
Gravity wraps Higgs boson
It is shown that, by rescaling the matter fields and metric tensor with appropriate powers of the Higgs field, the Higgs boson can be wholly transferred from material sector to the gravity sector in which it possesses only gravitational interactions and escapes detection in collider experiments. The Higgs boson gets buried in a scalar-tensor theory of gravity wherein it might be of relevance for Dark Energy. It is absent from the electroweak spectrum yet leptons, quarks and vector bosons possess their already known properties. The Higgs boson can contact with the matter sector via only the higher-dimensional operators suppressed by a cutoff scale.
Demir, Durmus A
Sodium Nightglow and Gravity Waves
Oscillations in intensity of NaD nightglow attributed to mesospheric gravity waves have bean studied. Fractional atmospheric density perturbations have been obtained by means of the linear gravity waves theory of Hines. Values of other parameters ...
A. Molina
C. : Fields on a random lattice. In: Progress in Gauge Field= Quantum gravity on the lattice Similarly, one can considerQuantum gravity on the lattice Herbert W. Hamber Received:
Gravity's weight on worldline fuzziness
We investigate a connection between recent results in 3D quantum gravity, providing an effective noncommutative-spacetime description, and some earlier heuristic descriptions of a quantum-gravity contribution to the fuzziness of the worldlines of particles. We show that 3D-gravity-inspired spacetime noncommutativity reflects some of the features suggested by previous heuristic arguments. Most notably, gravity-induced worldline fuzziness, while irrelevantly small on terrestrial scales, could be observably large for propagation of particles over cosmological distances.
Amelino-Camelia, Giovanni; Rosati, Giacomo
Massive gravity on a brane
Dam, Veltman and Zakharov [13], implies that the tensor structure of the gravitational interaction deviates from that of Einstein gravity.
Chacko, Z.; Graesser, M.L.; Grojean, C.; Pilo, L.
New probe of modified gravity
We suggest a new efficient way to constrain a certain class of large scale modifications of gravity. We show that the scale-free relation between density and size of Dark Matter halos, predicted within the LambdaCDM model with Newtonian gravity, gets modified in a wide class of theories of modified gravity.
Boyarsky, Alexey
D-Dimensional Log Gravity
We study Einstein gravity in dimensions $D\\geq 4$ modified by curvature squared at critical point where the theory contains only massless gravitons. We show that at the critical point a new mode appears leading to a logarithmic gravity in the theory. The corresponding logarithmic solution may provide a gravity description of logarithmic CFT in higher dimensions.
Alishahiha, Mohsen
5, 1102911054, 2005 Convective gravity
ACPD 5, 1102911054, 2005 Convective gravity waves at mid-latitudes Y. G. Choi et al. Title Page Discussions Wind-profiler observations of gravity waves produced by convection at mid-latitudes Y. G. Choi111054, 2005 Convective gravity waves at mid-latitudes Y. G. Choi et al. Title Page Abstract Introduction
Paris-Sud XI, Université de
CFT, Integrable Models Liouville Gravity
CFT, Integrable Models And Liouville Gravity Chernogolovka 2009 Sunday June 28, 2009. Conference as one of components of their L, A pairs. #12;CFT, Integrable Models And Liouville Gravity Chernogolovka Gravity Chernogolovka, 2009 Tuesday June 30, 2009. CONFERENCE HALL 09:3010:10 Herman Boos (Wuppertal
Fominov, Yakov
From Classical To Quantum Gravity: Introduction to Loop Quantum Gravity
We present an introduction to the canonical quantization of gravity performed in loop quantum gravity, based on lectures held at the 3rd quantum geometry and quantum gravity school in Zakopane in 2011. A special feature of this introduction is the inclusion of new proposals for coupling matter to gravity that can be used to deparametrize the theory, thus making its dynamics more tractable. The classical and quantum aspects of these new proposals are explained alongside the standard quantization of vacuum general relativity in loop quantum gravity.
Giesel, Kristina
Even-dimensional topological gravity from Chern-Simons gravity
It is shown that the topological action for gravity in 2n-dimensions can be obtained from the 2n+1-dimensional Chern-Simons gravity genuinely invariant under the Poincare group. The 2n-dimensional topological gravity is described by the dynamics of the boundary of a 2n+1-dimensional Chern-Simons gravity theory with suitable boundary conditions. The field $\\phi^{a}$, which is necessary to construct this type of topological gravity in even dimensions, is identified with the coset field associated with the non-linear realizations of the Poincare group ISO(d-1,1).
Nelson Merino; Alfredo Perez; Patricio Salgado
Bigravity and Massive Gravity
We discuss some issues concerning the global structure of spherically symmetric solutions of bigravity. We propose maximal extensions of manifolds where two causal structure coexist. Besides we make some comments about the perturbations of these solutions and their relation to massive gravity and the cosmological constant problem.
D. Blas
Isometrodynamics and Gravity
Isometrodynamics (ID), the gauge theory of the group of volume-preserving diffeomorphisms of an "inner" D-dimensional flat space, is tentatively interpreted as a fundamental theory of gravity. Dimensional analysis shows that the Planck length l_P - and through it \\hbar and \\Gamma - enters the gauge field action linking ID and gravity in a natural way. Noting that the ID gauge field couples solely through derivatives acting on "inner" space variables all ID fields are Taylor-expanded in "inner" space. Integrating out the "inner" space variables yields an effective field theory for the coefficient fields with l_P^2 emerging as the expansion parameter. For \\hbar goint to zero only the leading order field does not vanish. This classical field couples to the matter Noether currents and charges related to the translation invariance in "inner" space. A model coupling this leading order field to a matter point source is established and solved. Interpreting the matter Noether charge in terms of gravitational mass Newton's inverse square law is finally derived for a static gauge field source and a slowly moving test particle. Gravity emerges as potentially related to field variations over "inner" space and might microscopically be described by the ID gauge field or equivalently by an infinite string of coefficient fields only the leading term of which is related to the macroscopical effects of gravity.
Christian Wiesendanger
Quantum Gravity and Turbulence
We apply recent advances in quantum gravity to the problem of turbulence. Adopting the AdS/CFT approach we propose a string theory of turbulence that explains the Kolmogorov scaling in 3+1 dimensions and the Kraichnan and Kolmogorov scalings in 2+1 dimensions. In the gravitational context, turbulence is intimately related to the properties of spacetime, or quantum, foam.
Vishnu Jejjala; Djordje Minic; Y. Jack Ng; Chia-Hsiung Tze
The gravity of light
A solution of the old problem raised by Tolman, Ehrenfest, Podolsky and Wheeler, concerning the lack of attraction of two light pencils "moving parallel", is proposed, considering that the light can be source of nonlinear gravitational waves corresponding (in the would be quantum theory of gravity) to spin-1 massless particles.
G. Sparano; G. Vilasi; S. Vilasi
High energy scattering in gravity and supergravity
We investigate features of perturbative gravity and supergravity by studying scattering in the ultraplanckian limit, and sharpen arguments that the dynamics is governed by long-distance physics. A simple example capturing aspects of the eikonal resummation suggests why short distance phenomena and in particular divergences or nonrenormalizability do not necessarily play a central role in this regime. A more profound problem is apparently unitarity. These considerations can be illustrated by showing that known gravity and supergravity amplitudes have the same long-distance behavior, despite the extra light states of supergravity, and this serves as an important check on long-range dynamics in a context where perturbative amplitudes are finite. We also argue that these considerations have other important implications: they obstruct probing the conjectured phenomenon of asymptotic safety through a physical scattering process, and ultraplanckian scattering exhibiting Regge behavior. These arguments sharpen the need to find a nonperturbative completion of gravity with mechanisms which restore unitarity in the strong gravity regime.
Steven B. Giddings; Maximilian Schmidt-Sommerfeld; Jeppe R. Andersen
Flavorful hybrid anomaly-gravity mediation
We consider supersymmetric models where anomaly and gravity mediation give comparable contributions to the soft terms and discuss how this can be realized in a five-dimensional brane world. The gaugino mass pattern of anomaly mediation is preserved in such a hybrid setup. The flavorful gravity-mediated contribution cures the tachyonic slepton problem of anomaly mediation. The supersymmetric flavor puzzle is solved by alignment. We explicitly show how a working flavor-tachyon link can be realized with Abelian flavor symmetries and give the characteristic signatures of the framework, including O(1) slepton mass splittings between different generations and between doublets and singlets. This provides opportunities for same flavor dilepton edge measurements with missing energy at the Large Hadron Collider (LHC). Rare lepton decay rates could be close to their current experimental limit. Compared to pure gravity mediation, the hybrid model is advantageous because it features a heavy gravitino which can avoid the cosmological gravitino problem of gravity-mediated models combined with leptogenesis.
Gross, Christian; Hiller, Gudrun [Institut fuer Physik, Technische Universitaet Dortmund, D-44221 Dortmund (Germany)
Quantum gravity and "singularities"
The paper concerns the fictitious entanglement of the so-called ``singularities'' in problems, pertaining to quantum gravity, due, in point of fact, to the way we try to employ, in that context, differential geometry, the latter being associated, in effect, by far, classically (:smooth manifolds), on the basis of an erroneous correspondence between what we may call/understand, as ``physical space'' and the ``cartesian-newtonian'' one.
Anastasios Mallios
Lorentz Breaking and Gravity
Gravitational theories with Lorentz violation must account for a number of possible features in order to be consistent theoretically and phenomenologically. A brief summary of these features is given here. They include evasion of a no-go theorem, connections between spontaneous Lorentz breaking and diffeomorphism breaking, the appearance of massless Nambu-Goldstone modes and massive Higgs modes, and the possibility of a Higgs mechanism in gravity.
R. Bluhm
Gravity, Dimension, Equilibrium, & Thermodynamics
Is it actually possible to interpret gravitation as space's property in a pure classical way. Then, we note that extended self-gravitating system equilibrium depends directly on the number of dimension of the space in which it evolves. Given those precisions, we review the principal thermodynamical knowledge in the context of classical gravity with arbitrary dimension of space. Stability analyses for bounded 3D systems, namely the Antonov instability paradigm, are then rapproched to some amazing properties of globular clusters and galaxies.
Jerome Perez
The Particle Adventure | What holds it together? | Gravity
holds it together? > Gravity Gravity What about gravity? Gravity is weird. It is clearly one of the fundamental interactions, but the Standard Model cannot satisfactorily explain...
Quantum gravity and inventory accumulation
We begin by studying inventory accumulation at a LIFO (last-in-first-out) retailer with two products. In the simplest version, the following occur with equal probability at each time step: first product ordered, first product produced, second product ordered, second product produced. The inventory thus evolves as a simple random walk on Z^2. In more interesting versions, a p fraction of customers orders the "freshest available" product regardless of type. We show that the corresponding random walks scale to Brownian motions with diffusion matrices depending on p. We then turn our attention to the critical Fortuin-Kastelyn random planar map model, which gives, for each q>0, a probability measure on random (discretized) two-dimensional surfaces decorated by loops, related to the q-state Potts model. A longstanding open problem is to show that as the discretization gets finer, the surfaces converge in law to a limiting (loop-decorated) random surface. The limit is expected to be a Liouville quantum gravity surface decorated by a conformal loop ensemble, with parameters depending on q. Thanks to a bijection between decorated planar maps and inventory trajectories (closely related to bijections of Bernardi and Mullin), our results about the latter imply convergence of the former in a particular topology. A phase transition occurs at p = 1/2, q=4.
Scott Sheffield
Einstein gravity as a 3D conformally invariant theory
We give an alternative description of the physical content of general relativity that does not require a Lorentz invariant spacetime. Instead, we find that gravity admits a dual description in terms of a theory where local size is irrelevant. The dual theory is invariant under foliation preserving 3-diffeomorphisms and 3D conformal transformations that preserve the 3-volume (for the spatially compact case). Locally, this symmetry is identical to that of Horava-Lifshitz gravity in the high energy limit but our theory is equivalent to Einstein gravity. Specifically, we find that the solutions of general relativity, in a gauge where the spatial hypersurfaces have constant mean extrinsic curvature, can be mapped to solutions of a particular gauge fixing of the dual theory. Moreover, this duality is not accidental. We provide a general geometric picture for our procedure that allows us to trade foliation invariance for conformal invariance. The dual theory provides a new proposal for the theory space of quantum gravity.
Henrique Gomes; Sean Gryb; Tim Koslowski
Gravity Methods | Open Energy Information
Gravity Methods Gravity Methods Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: Gravity Methods Details Activities (0) Areas (0) Regions (0) NEPA(3) Exploration Technique Information Exploration Group: Geophysical Techniques Exploration Sub Group: Gravity Techniques Parent Exploration Technique: Information Provided by Technique Lithology: Stratigraphic/Structural: Hydrological: Thermal: Dictionary.png Gravity Methods: No definition has been provided for this term. Add a Definition References No exploration activities found. Document # Analysis Type Applicant Geothermal Area Lead Agency District Office Field Office Mineral Manager Surface Manager Development Phase(s) Techniques NVN-084630 CU Vulcan Energy Patua Geothermal Area BLM Nevada State Office BLM Winnemucca District Office BLM Humboldt River Field Office BLM BLM Geothermal/Exploration Gravity Methods
Non-Newtonian gravity in finite nuclei
In this talk, we report our recent study of constraining the non-Newtonian gravity at femtometer scale. We incorporate the Yukawa-type non-Newtonian gravitational potential consistently to the Skyrme functional form using the exact treatment for the direct contribution and density-matrix expansion method for the exchange contribution. The effects from the non-Newtonian potential on finite nuclei properties are then studied together with a well-tested Skyrme force. Assuming that the framework without non-Newtonian gravity can explain the binding energies and charge radii of medium to heavy nuclei within 2% error, we set an upper limit for the strength of the non-Newtonian gravitational potential at femtometer scale.
Xu, Jun; Chen, Lie-Wen; Zheng, Hao
D-dimensional log gravity
We study Einstein gravity in dimensions D{>=}4 modified by curvature squared at critical point where the theory contains only massless gravitons. We show that at the critical point a new mode appears leading to a logarithmic gravity in the theory. The corresponding logarithmic solution may provide a gravity description of logarithmic conformal field theories (CFT) in higher dimensions. We note also that for special values of the parameters of the theory, the model admits solutions with nonrelativistic isometries.
Alishahiha, Mohsen; Fareghbal, Reza [School of physics, Institute for Research in Fundamental Sciences (IPM), P. O. Box 19395-5531, Tehran (Iran, Islamic Republic of)
Dark Matter and Dark Energy as Effects of Quantum Gravity
I present a theory of quantum gravity based on the principle of gravitational energy fluctuations. Gravitational energy fluctuations -- gravitons -- are responsible for elastic scattering of subatomic particles. Such scattering corresponds to complimentary force -- graviton scattering force -- arising in gravitational interaction in addition to Newtonian gravity. The strength of the graviton scattering force is proportional to the graviton scattering probability. Unlike Newtonian gravity the graviton scattering force follows the 1/r law and dominates the former on cosmological scale in the limit of low orbital accelerations. Similarly to Modified Newtonian Dynamics the quantum gravity accounts for variations in observed M/L ratios of diverse stellar systems ranging from dwarf spheroid galaxies to X-ray galaxy clusters without requiring an invisible matter (which is still required by MOND in X-Ray cluster cores). Unlike MOND the presented theory neither violates cornerstone Newton Laws nor suffers from the ambiguity of acceleration frames while enjoying vast experimental evidence usually cited in favor of MOND. To ascertain the validity of the presented theory I have examined the predictions of quantum gravity for dwarf spheroid, ordinary and giant elliptic galaxies, and X-ray clusters. In all cases quantum gravity yields M/L ratios and scaling relations consistent with observations. Quantum gravity accounts for the tilt of the Fundamental Plane of elliptical galaxies erasing the differences in M/L vs. luminosity relations for faint and bright ellipticals, which cannot be easily explained by CDM model. Lastly, by analyzing the behavior of the gravitational energy fluctuations in the limit of high matter density expected in the early Universe I show that primordial inflation and dark energy (i.e. non-zero cosmological constant) arise as natural effects of quantum gravity in the expanding Universe.
Max I. Fomitchev
Is Gravity an Entropic Force?
The remarkable connections between gravity and thermodynamics seem to imply that gravity is not fundamental but emergent, and in particular, as Verlinde suggested, gravity is probably an entropic force. In this paper, we will argue that the idea of gravity as an entropic force is debatable. It is shown that there is no convincing analogy between gravity and entropic force in Verlinde's example. Neither holographic screen nor test particle satisfies all requirements for the existence of entropic force in a thermodynamics system. Furthermore, we show that the entropy increase of the screen is not caused by its statistical tendency to increase entropy as required by the existence of entropic force, but in fact caused by gravity. Therefore, Verlinde's argument for the entropic origin of gravity is problematic. In addition, we argue that the existence of a minimum size of spacetime, together with the Heisenberg uncertainty principle in quantum theory, may imply the fundamental existence of gravity as a geometric property of spacetime. This may provide a further support for the conclusion that gravity is not an entropic force.
Topological methods in quantum gravity.
??The main technical problem with background independent approaches to quantum gravity is inapplicability of standard quantum field theory methods. New methods are needed which would� (more)
Starodubtsev, Artem
Forecasting Cosmological Constraints from Redshift Surveys
Observations of redshift-space distortions in spectroscopic galaxy surveys offer an attractive method for observing the build-up of cosmological structure, which depends both on the expansion rate of the Universe and our theory of gravity. In this paper we present a formalism for forecasting the constraints on the growth of structure which would arise in an idealized survey. This Fisher matrix based formalism can be used to study the power and aid in the design of future surveys.
Martin White; Yong-Seon Song; Will J. Percival
It is shown that, under a conformal transformation with reference to the Higgs field, the Higgs boson can be completely decoupled from electroweak interactions with no apparent change in known properties of leptons, quarks and vector bosons. Higgs boson becomes part of a scalar-tensor gravity which can be relevant for Dark Energy. It interacts with matter sector via higher-dimensional terms (e.g. neutrino Majorana mass), and via the fields (of new physics) whose masses are not generated by the Higgs mechanism. Dark Matter and two-Higgs-doublet model are the simplest examples.
Durmus A. Demir
Discrete gravity models and Loop Quantum Gravity: a short review
We review the relation between loop quantum gravity on a fixed graph and discrete models of gravity. We compare Regge and twisted geometries, and discuss discrete actions based on twisted geometries and on the discretization of the Plebanski action. We discuss the role of discrete geometries in the spin foam formalism, with particular attention to the definition of the simplicity constraints.
Dupuis, Maite; Speziale, Simone
Photon and graviton mass limits
We review past and current studies of possible long-distance, low-frequency deviations from Maxwell electrodynamics and Einstein gravity. Both have passed through three phases: (1) Testing the inverse-square laws of Newton and Coulomb, (2) Seeking a nonzero value for the rest mass of photon or graviton, and (3) Considering more degrees of freedom, allowing mass while preserving gauge or general-coordinate invariance. For electrodynamics there continues to be no sign of any deviation. Since our previous review the lower limit on the photon Compton wavelength (associated with weakening of electromagnetic fields in vacuum over large distance scale) has improved by four orders of magnitude, to about one astronomical unit. Rapid current progress in astronomical observations makes it likely that there will be further advances. These ultimately could yield a bound exceeding galactic dimensions, as has long been contemplated. Meanwhile, for gravity there have been strong arguments about even the concept of a graviton rest mass. At the same time there are striking observations, commonly labeled 'dark matter' and 'dark energy' that some argue imply modified gravity. This makes the questions for gravity much more interesting. For dark matter, which involves increased attraction at large distances, any explanation by modified gravity would be qualitatively different from graviton mass. Because dark energy is associated with reduced attraction at large distances, it might be explained by a graviton-mass-like effect.
Nieto, Michael [Los Alamos National Laboratory; Goldhaber Scharff, Alfred [SUNY
Gravity and magnetic features and their relationship to the geothermal system in southwestern South Dakota
An attempt is made to determine the sources that are responsible for producing geothermal anomalies observed within the southern Black Hills region. Lithologic and structural boundaries residing in the upper crust and their relationship to the geothermal system are discussed. A regional gravity survey was supplemented by a regional aeromagnetic survey.
Hildenbrand, T.G.; Kucks, R.P.
Gravity-Driven Intrusions in Stratified Fluids
5.5.1 Five interleaving interfacial gravity currents 5.5.2Ten interleaving interfacial gravity currents . 5.6in Iceland showing multiple gravity-driven intrusions c �
Maurer, Benjamin D.
The role of information in gravity
It is argued that particle-specific information on energy-momentum adjusts the strength of gravity. This form of gravity has no free parameters, preserves Einstein gravity locally and predicts 6 times stronger accelerations on galaxy scales.
M. Spaans
Will multiple probes of dark energy find modified gravity?
One of the most pressing issues in cosmology is whether general relativity (GR) plus a dark sector is the underlying physical theory or whether a modified gravity model is needed. Upcoming dark energy experiments designed to probe dark energy with multiple methods can address this question by comparing the results of the different methods in constraining dark energy parameters. Disagreement would signal the breakdown of the assumed model (GR plus dark energy). We study the power of this consistency test by projecting constraints in the w{sub 0}-w{sub a} plane from the four different techniques of the Dark Energy Survey in the event that the underlying true model is modified gravity. We find that the standard technique of looking for overlap has some shortcomings, and we propose an alternative, more powerful Multidimensional Consistency Test. We introduce the methodology for projecting whether a given experiment will be able to use this test to distinguish a modified gravity model from GR.
Shapiro, Charles [Institute of Cosmology and Gravitation, Portsmouth, PO1 3FX (United Kingdom); Dodelson, Scott [Center for Particle Astrophysics, Fermi National Accelerator Laboratory, Batavia, Illinois 60510 (United States); Department of Astronomy and Astrophysics, University of Chicago, Chicago, Illinois 60637 (United States); Kavli Institute for Cosmological Physics, Chicago, Illinois 60637 (United States); Hoyle, Ben [Institut de Ciencies del Cosmos, Barcelona (Spain); Samushia, Lado [Institute of Cosmology and Gravitation, Portsmouth, PO1 3FX (United Kingdom); National Abastumani Astrophysical Observatory, Ilia State University, 2A Kazbegi Ave, GE-0160 Tbilisi (Georgia); Flaugher, Brenna [Center for Particle Astrophysics, Fermi National Accelerator Laboratory, Batavia, Illinois 60510 (United States)
Refraction Survey At Kilauea East Rift Area (Broyles, Et Al....
Structure Of The Lower East Rift Zone Of Kilauea Volcano, Hawaii, From Seismic And Gravity Data Retrieved from "http:en.openei.orgwindex.php?titleRefractionSurveyAtKila...
Tolerance Limits
Gravity Waves in the Sun
We present numerical simulations of penetrative convection and gravity wave excitation in the Sun. Gravity waves are self-consistently generated by a convective zone overlying a radiative interior. We produce power spectra for gravity waves in the radiative region as well as estimates for the energy flux of gravity waves below the convection zone. We calculate a peak energy flux in waves below the convection zone to be three orders of magnitude smaller than previous estimates for m=1. The simulations show that the linear dispersion relation is a good approximation only deep below the convective-radiative boundary. Both low frequency propagating gravity waves as well as higher frequency standing modes are generated; although we find that convection does not continually drive the standing g-mode frequencies.
Tamara M. Rogers; Gary A. Glatzmaier
Geometry and symmetries in lattice spinor gravity
Lattice spinor gravity is a proposal for regularized quantum gravity based on fermionic degrees of freedom. In our lattice model the local Lorentz symmetry is generalized to complex transformation parameters. The difference between space and time is not put in a priori, and the euclidean and the Minkowski quantum field theory are unified in one functional integral. The metric and its signature arise as a result of the dynamics, corresponding to a given ground state or cosmological solution. Geometrical objects as the vierbein, spin connection or the metric are expectation values of collective fields built from an even number of fermions. The quantum effective action for the metric is invariant under general coordinate transformations in the continuum limit. The action of our model is found to be also invariant under gauge transformations. We observe a 'geometrical entanglement' of gauge- and Lorentz-transformations due to geometrical objects transforming non-trivially under both types of symmetry transformations. - Highlights: Black-Right-Pointing-Pointer We formulate the geometrical aspects of a proposal for a lattice regularized model of quantum gravity. Black-Right-Pointing-Pointer The vierbein shows an entanglement between Lorentz symmetry and gauge symmetry. Black-Right-Pointing-Pointer Euclidean and Minkowski signatures of the collective metric and the vierbein are described within the same functional integral.
Wetterich, C., E-mail: firstname.lastname@example.com
A gravity model for the Coso geothermal area, California
Two- and three-dimensional gravity modeling was done using gridded Bouguer gravity data covering a 45 {times} 45 km region over the Coso geothermal area in an effort to identify features related to the heat source and to seek possible evidence for an underlying magma chamber. Isostatic and terrain corrected Bouguer gravity data for about 1300 gravity stations were obtained from the US Geological Survey. After the data were checked, the gravity values were gridded at 1 km centers for the area of interest centered on the Coso volcanic field. Most of the gravity variations can be explained by two lithologic units: (1) low density wedges of Quarternary alluvium with interbedded thin basalts (2.4 g/cm{sup 3}) filling the Rose Valley and Coso Basin/Indian Wells Valley, and (2) low density cover of Tertiary volcanic rocks and intercalated Coso Formation (2.49 g/cm{sup 3}). A 3-D iterative approach was used to find the thicknesses of both units. The gravity anomaly remaining after effects from Units 1 and 2 are removed is a broad north-south-trending low whose major peak lies 5 km north of Sugarloaf Mountain, the largest of the less than 0.3 m.y. old rhyolite domes in the Coso Range. Most of this residual anomaly can be accounted for by a deep, low-density (2.47 g/cm{sup 3}) prismatic body extending from 8 to about 30 km below the surface. While some of this anomaly might be associated with fractured Sierran granitic rocks, its close correlation to a low-velocity zone with comparable geometry suggests that the residual anomaly is probably caused a large zone of partial melt underlying the rhyolite domes of the Coso Range. 12 refs., 9 figs.
Feighner, M.A.; Goldstein, N.E.
Gravity quantized: Loop quantum gravity with a scalar field
...''but we do not have quantum gravity.'' This phrase is often used when analysis of a physical problem enters the regime in which quantum gravity effects should be taken into account. In fact, there are several models of the gravitational field coupled to (scalar) fields for which the quantization procedure can be completed using loop quantum gravity techniques. The model we present in this paper consists of the gravitational field coupled to a scalar field. The result has similar structure to the loop quantum cosmology models, except that it involves all the local degrees of freedom of the gravitational field because no symmetry reduction has been performed at the classical level.
Domagala, Marcin; Kaminski, Wojciech [Instytut Fizyki Teoretycznej, Uniwersytet Warszawski, ul. Hoza 69, 00-681 Warszawa (Warsaw), Polska (Poland) (Poland); Giesel, Kristina [Excellence Cluster Universe, Technische Universitaet Muenchen, Boltzmannstrasse 2, 85748 Garching (Germany); Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803 (United States); Lewandowski, Jerzy [Instytut Fizyki Teoretycznej, Uniwersytet Warszawski, ul. Hoza 69, 00-681 Warszawa (Warsaw), Polska (Poland) (Poland); Institute for Gravitation and the Cosmos, Physics Department, Penn State, University Park, Pennsylvania 16802 (United States)
Geophysics IV. Gravity, Magnetic, and Magnetotelluric Methods
During the past two decades, the technology of geophysics has exploded. At the same time, the petroleum industry has been forced to look for more and more subtle traps in more and more difficult terrain. The choice of papers in this geophysics reprint volume reflects this evolution. The papers were chosen to help geologists, not geophysicists, enhance their knowledge of geophysics. Math-intensive papers were excluded because those papers are relatively esoteric and have limited applicability for most geologists. This volume concentrates on gravity, magnetic, and magnetotelluric methods. Each of the 10 papers were abstracted and indexed for the U.S. Department of Energy's Energy Data Base.
Beaumont, E.A.; Foster, N.H. (comps.)
Collapse of charged scalar field in dilaton gravity
We elaborated the gravitational collapse of a self-gravitating complex charged scalar field in the context of the low-energy limit of the string theory, the so-called dilaton gravity. We begin with the regular spacetime and follow the evolution through the formation of an apparent horizon and the final central singularity.
Borkowska, Anna; Rogatko, Marek; Moderski, Rafal [Institute of Physics, Maria Curie-Sklodowska University, 20-031 Lublin, pl. Marii Curie-Sklodowskiej 1 (Poland); Nicolaus Copernicus Astronomical Center, Polish Academy of Sciences, 00-716 Warsaw, Bartycka 18 (Poland)
Quantum Histories and Quantum Gravity
This paper reviews the histories approach to quantum mechanics. This discussion is then applied to theories of quantum gravity. It is argued that some of the quantum histories must approximate (in a suitable sense) to classical histories, if the correct classical regime is to be recovered. This observation has significance for the formulation of new theories (such as quantum gravity theories) as it puts a constraint on the kinematics, if the quantum/classical correspondence principle is to be preserved. Consequences for quantum gravity, particularly for Lorentz symmetry and the idea of "emergent geometry", are discussed.
Joe Henson
Spin-gravity coupling and gravity-induced quantum phases
External gravitational fields induce phase factors in the wave functions of particles. The phases are exact to first order in the background gravitational field, are manifestly covariant and gauge invariant and provide a useful tool for the study of spin-gravity coupling and of the optics of particles in gravitational or inertial fields. We discuss the role that spin-gravity coupling plays in particular problems.
Giorgio Papini
Nonlinear Evolution of an Upward Propagating Gravity Wave: Overturning, Convection, Transience and Turbulence
A numerical simulation of the nonlinear evolution of an upward propagating gravity wave shows that over-turning (the turning over of isopotential temperature surfaces) is the mechanism responsible for limiting the growth of the wave. Wave ...
R. L. Walterscheid; G. Schubert
Comments on "Solar System constraints to general f(R) gravity"
We comment on, and complete, the analysis of the weak field limit of metric f(R) gravity in T. Chiba, T.L. Smith, and A.L. Erickcek, Phys. Rev. D 75, 124014 (2007).
Valerio Faraoni; Nicolas Lanahan-Tremblay
Normal Mode Initialization and the Generation of Gravity Waves by Quasi-Geostrophic Forcing
Several numerical weather prediction models now use nonlinear normal-mode initialization schemes. These schemes describe balanced states which act to limit the initial presence of high-frequency gravity waves and their subsequent growth by ...
Ronald M. Errico
Oklahoma, Kansas, Missouri Refinery District API Gravity ...
U.S. Energy Information Administration (EIA)
Oklahoma, Kansas, Missouri Refinery District API Gravity (Weighted Average) of Crude Oil Input to Refineries (Degree)
Intrusive gravity currents in two-layer
Intrusive gravity currents in two-layer stratified media Morris R. Flynn & Paul F. Linden Dept to as a gravity current · In contrast to waves, gravity currents transport significant mass (e.g. fluid parcels, sediment, insects, etc.) Introduction Gravity currents in the environment www
Flynn, Morris R.
Gravity's Cosmic ShadowsGravity's Cosmic Shadows A Mathematical UnveilingA Mathematical Unveiling
Gravity's Cosmic ShadowsGravity's Cosmic Shadows A Mathematical UnveilingA Mathematical Unveiling of gravity on light SUNSUN #12;Gravitational Lensing - action of gravity on light SUNSUN #12;Gravitational Lensing - action of gravity on light SUNSUN nn 1801: Johann von1801: Johann von SoldnerSoldner (Newtonian
Weinberger, Hans
Cosmography of f(R) gravity
It is nowadays accepted that the universe is undergoing a phase of accelerated expansion as tested by the Hubble diagram of Type Ia Supernovae (SNeIa) and several LSS observations. Future SNeIa surveys and other probes will make it possible to better characterize the dynamical state of the universe renewing the interest in cosmography which allows a model independent analysis of the distance - redshift relation. On the other hand, fourth order theories of gravity, also referred to as $f(R)$ gravity, have attracted a lot of interest since they could be able to explain the accelerated expansion without any dark energy. We show here how it is possible to relate the cosmographic parameters (namely the deceleration $q_0$, the jerk $j_0$, the snap $s_0$ and the lerk $l_0$ parameters) to the present day values of $f(R)$ and its derivatives $f^{(n)}(R) = d^nf/dR^n$ (with $n = 1, 2, 3$) thus offering a new tool to constrain such higher order models. Our analysis thus offers the possibility to relate the model independ...
Capozziello, S; Salzano, V
It is nowadays accepted that the universe is undergoing a phase of accelerated expansion as tested by the Hubble diagram of Type Ia Supernovae (SNeIa) and several LSS observations. Future SNeIa surveys and other probes will make it possible to better characterize the dynamical state of the universe renewing the interest in cosmography which allows a model independent analysis of the distance - redshift relation. On the other hand, fourth order theories of gravity, also referred to as $f(R)$ gravity, have attracted a lot of interest since they could be able to explain the accelerated expansion without any dark energy. We show here how it is possible to relate the cosmographic parameters (namely the deceleration $q_0$, the jerk $j_0$, the snap $s_0$ and the lerk $l_0$ parameters) to the present day values of $f(R)$ and its derivatives $f^{(n)}(R) = d^nf/dR^n$ (with $n = 1, 2, 3$) thus offering a new tool to constrain such higher order models. Our analysis thus offers the possibility to relate the model independent results coming from cosmography to the theoretically motivated assumptions of $f(R)$ cosmology.
S. Capozziello; V. F. Cardone; V. Salzano
Gravity Techniques | Open Energy Information
Gravity Techniques Gravity Techniques Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: Gravity Techniques Details Activities (0) Areas (0) Regions (0) NEPA(1) Exploration Technique Information Exploration Group: Geophysical Techniques Exploration Sub Group: Gravity Techniques Parent Exploration Technique: Geophysical Techniques Information Provided by Technique Lithology: Distribution of density in the subsurface enables inference of rock type. Stratigraphic/Structural: Delineation of steeply dipping formations, geological discontinuities and faults, intrusions and the deposition of silicates due to hydrothermal activity. Hydrological: Density of sedimentary rocks are strongly influenced by fluid contained within pore space. Dry bulk density refers to the rock with no moisture, while the wet bulk density accounts for water saturation; fluid content may alter density by up to 30%.(Sharma, 1997)
Numerical Dispersion of Gravity Waves
When atmospheric gravity waves are simulated in numerical models, they are not only dispersive for physical but also for numerical reasons. Their wave properties (e.g., damping or propagation speed and direction) can depend on grid spacing as ...
Guido Schroeder; K. Heinke Schl�nzen
Critical Gravity in Four Dimensions
We study four-dimensional gravity theories that are rendered renormalizable by the inclusion of curvature-squared terms to the usual Einstein action with a cosmological constant. By choosing the parameters appropriately, the massive scalar mode can be eliminated and the massive spin-2 mode can become massless. This ''critical'' theory may be viewed as a four-dimensional analogue of chiral topologically massive gravity, or of critical 'new massive gravity' with a cosmological constant, in three dimensions. We find that the on-shell energy for the remaining massless gravitons vanishes. There are also logarithmic spin-2 modes, which have positive energy. The mass and entropy of standard Schwarzschild-type black holes vanish. The critical theory might provide a consistent toy model for quantum gravity in four dimensions.
Lue, H. [China Economics and Management Academy, Central University of Finance and Economics, Beijing 100081 (China); Institute for Advanced Study, Shenzhen University, Nanhai Avenue 3688, Shenzhen 518060 (China); Pope, C. N. [George P. and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy, Texas A and M University, College Station, Texas 77843 (United States); DAMTP, Centre for Mathematical Sciences, Cambridge University, Wilberforce Road, Cambridge CB3 OWA (United Kingdom)
Structure formation in modified gravity
We pursue a (1+3) ?covariant analysis of cosmological peculiar velocity of pressure?free matter induced by the matter density perturbations in modified f(R) gravity theories. Instead of working in a quasi?Newtonian Eulerian frame
D. M. Solomons; P. K. S. Dunsby; S. Carloni
Gravity Currents in Aquatic Canopies
A lock exchange experiment is used to investigate the propagation of gravity currents through a random array of rigid, emergent cylinders which represents a canopy of aquatic plants. As canopy drag increases, the propagating ...
Tanino, Yukie
Momentum Balance of Gravity Flows
A unified scale analysis of the momentum balance of downslope gravity flows is developed to organize previous theories for the case of negligible ambient flow and fixed temperature deficit scale. The values of several nondimensional parameters ...
L. Mahrt
Quench cooling under reduced gravity
We report the quench cooling experiments performed with liquid O2 under different levels of gravity simulated with the magnetic gravity compensation. A copper disk is quenched from 270K to 90K. It is found that the cooling time in microgravity is very long in comparison with any other gravity level. This phenomenon is explained by the isolation effect of the gas surrounding the disk. The liquid subcooling is shown to drastically improuve the heat exchange thus reducing the cooling time (about 20 times). The effect of subcooling on the heat transfer is analyzed at different gravity levels. It is shown that such type of experiments cannot be used for the analysis of the critical heat flux (CHF) of the boiling crisis. The minimum heat flux (MHF) of boiling is analyzed instead.
Chatain, D; Nikolayev, V S; Beysens, D
Performance characteristics of gravity-assisted, potassium heat pipes
Experiments with potassium-stainless steel gravity-assisted heat pipes were performed. Performance limitations due to entrainment or flooding of the liquid return flow are compared with analytical model predictions. The effect of heated pool height was investigated and problems with surface wetting are discussed. A comparison between entrainment limits for smooth-walled and textured-walled heat pipes was made and a minimum internal surface texturing depth is suggested.
Prenger, F.C.; Keddy, E.S.; Sena, J.T.
Attractions of Affine Quantum Gravity
All attempts to quantize gravity face several difficult problems. Among these problems are: (i) metric positivity (positivity of the spatial distance between distinct points), (ii) the presence of anomalies (partial second-class nature of the quantum constraints), and (iii) perturbative nonrenormalizability (the need for infinitely many distinct counterterms). In this report, a relatively nontechnical discussion is presented about how the program of affine quantum gravity proposes to deal with these problems.
John R. Klauder
Lectures on Screened Modified Gravity
The acceleration of the expansion of the Universe has led to the construction of Dark Energy models where a light scalar field may have a range reaching up to cosmological scales. Screening mechanisms allow these models to evade the tight gravitational tests in the solar system and the laboratory. I will briefly review some of the salient features of screened modified gravity models of the chameleon, dilaton or symmetron types using $f(R)$ gravity as a template.
Philippe Brax
Observational Tests of Modified Gravity
Modified gravity theories have richer observational consequences for large-scale structure than conventional dark energy models, in that different observables are not described by a single growth factor even in the linear regime. We examine the relationships between perturbations in the metric potentials, density and velocity fields, and discuss strategies for measuring them using gravitational lensing, galaxy cluster abundances, galaxy clustering/dynamics and the ISW effect. We show how a broad class of gravity theories can be tested by combining these probes. A robust way to interpret observations is by constraining two key functions: the ratio of the two metric potentials, and the ratio of the Gravitational ``constant'' in the Poisson equation to Newton's constant. We also discuss quasilinear effects that carry signatures of gravity, such as through induced three-point correlations. Clustering of dark energy can mimic features of modified gravity theories and thus confuse the search for distinct signatures of such theories. It can produce pressure perturbations and anisotropic stresses, which breaks the equality between the two metric potentials even in general relativity. With these two extra degrees of freedom, can a clustered dark energy model mimic modified gravity models in all observational tests? We show with specific examples that observational constraints on both the metric potentials and density perturbations can in principle distinguish modifications of gravity from dark energy models. We compare our result with other recent studies that have slightly different assumptions (and apparently contradictory conclusions).
Bhuvnesh Jain; Pengjie Zhang
Spectral dimension in graph models of causal quantum gravity
The phenomenon of scale dependent spectral dimension has attracted special interest in the quantum gravity community over the last eight years. It was first observed in computer simulations of the causal dynamical triangulation (CDT) approach to quantum gravity and refers to the reduction of the spectral dimension from 4 at classical scales to 2 at short distances. Thereafter several authors confirmed a similar result from different approaches to quantum gravity. Despite the contribution from different approaches, no analytical model was proposed to explain the numerical results as the continuum limit of CDT. In this thesis we introduce graph ensembles as toy models of CDT and show that both the continuum limit and a scale dependent spectral dimension can be defined rigorously. First we focus on a simple graph ensemble, the random comb. It does not have any dynamics from the gravity point of view, but serves as an instructive toy model to introduce the characteristic scale of the graph, study the continuum limit and define the scale dependent spectral dimension. Having defined the continuum limit, we study the reduction of the spectral dimension on more realistic toy models, the multigraph ensembles, which serve as a radial approximation of CDT. We focus on the (recurrent) multigraph approximation of the two-dimensional CDT whose ensemble measure is analytically controlled. The latter comes from the critical Galton-Watson process conditioned on non-extinction. Next we turn our attention to transient multigraph ensembles, corresponding to higher-dimensional CDT. Firstly we study their fractal properties and secondly calculate the scale dependent spectral dimension and compare it to computer simulations. We comment further on the relation between Horava-Lifshitz gravity, asymptotic safety, multifractional spacetimes and CDT-like models.
Georgios Giasemidis
Seismic refraction and gravity surveys of Pilgrim Springs KGRA, Alaska
Pilgrim Springs KGRA is located in a major northeast-trending tectonic depression on the Seward Peninsula, Alaska. Refraction has identified a layer which coincides with a hot artesian aquifer in hydrothermally cemented sediments. The presence of a hydrothermal cap rock is possible but not proven. Crystalline bedrock lies at least 200 m beneath the springs, dropping to possibly 500 m in depth immediately to the southwest in what appears to be a trough bounded by normal faults on the north, south and east. Pilgrim Springs are situated over the intersection of the two faults at the northeastern corner of this trough, suggesting that one or both faults are acting as conduits to the springs. Pilgrim Springs are associated with extensional tectonics and recent alkalic volcanism suggestive of active rifting in the region.
Lockhart, A.; Kienle J.
Ground Gravity Survey At Lightning Dock Area (Warpinski, Et Al...
not indicated DOE-funding Unknown Notes Update to Warpinski, et al., 2002 References N. R. Warpinski, A. R. Sattler, R. Fortuna, D. A. Sanchez, J. Nathwani (2004) Geothermal...
Dilaton Gravity, Poisson Sigma Models and Loop Quantum Gravity
Spherically symmetric gravity in Ashtekar variables coupled to Yang-Mills theory in two dimensions and its relation to dilaton gravity and Poisson sigma models are discussed. After introducing its loop quantization, quantum corrections for inverse triad components are shown to provide a consistent deformation without anomalies. The relation to Poisson sigma models provides a covariant action principle of the quantum corrected theory with effective couplings. Results are also used to provide loop quantizations of spherically symmetric models in arbitrary D space-time dimensions.
Martin Bojowald; Juan D. Reyes
Survey Expectations
of Michigan and is known as the Michigan survey, with many other similar surveys conducted across OECD countries so as to provide up to date information on consumer expectations. Questions on expectations are also sometimes included in panel surveys... be formed, do of course make it possible to assess whether, or how far, such expectations are well-founded by comparing the experiences of individual households with their prior expectations. A key aspect of the Michigan survey, and of many other more recent...
Pesaran, M Hashem; Weale, Martin
Modified gravity from the quantum part of the metric
It is shown that if a metric in quantum gravity can be decomposed as a sum of classical and quantum parts then Einstein quantum gravity looks approximately like modified gravity with a nonminimal interaction between gravity and matter.
Vladimir Dzhunushaliev; Vladimir Folomeev; Burkhard Kleihaus; Jutta Kunz
Three dimensional gravity modeling techniques with application to the Ennis Geothermal Area: Final report: Part 1
3-D gravity modeling was done in the area of the Ennis hot spring in an attempt to determine controlling structure of the Ennis hot spring. The modeling was done in a two-step process where: 1) The topography was modeled by modeling the valley fill from the highest elevation in the modeling area to some elevation below the lowest station elevation using Talwani and Ewing's (1960) method of modeling with vertically-stacked, horizontal, n-sided polygons. Once the gravity contributions of the valley fill included in this ''topographic model'' are calculated, they were removed from the original gravity data; 2) The remaining valley fill was modeled using blocks where the 3-D algorithm for modeling with blocks results from integrating the gravity formula in the X and Z directions and approximating the integration in the Y-direction using a quadrature formula. Finally, an inverse 3-D gravity modeling program was written to automatically adjust the bedrock topography output from this two-step modeling process. The gravity data calculated from the adjusted bedrock topography, output from the inverse modeling program, should match the observed gravity data within the error of the survey. 43 refs., 40 figs., 9 tabs.
Semmens, D.
A Regional Strategy For Geothermal Exploration With Emphasis On Gravity And
Strategy For Geothermal Exploration With Emphasis On Gravity And Strategy For Geothermal Exploration With Emphasis On Gravity And Magnetotellurics Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: A Regional Strategy For Geothermal Exploration With Emphasis On Gravity And Magnetotellurics Details Activities (4) Areas (2) Regions (0) Abstract: As part of the resource evaluation and exploration program conducted by Los Alamos Scientific Laboratory for the national Hot Dry Rock (HDR) Geothermal Program, a regional magnetotelluric (MT) survey of New Mexico and Arizona is being performed. The MT lines are being located in areas where the results of analysis of residual gravity anomaly maps of Arizona and New Mexico, integrated with other geologic and geophysical studies indicate the greatest potential for HDR resources. The residual
Enhanced and Inhibited Gravity Wave Spectra
Balloon measurements were used to investigate gravity waves in the upper troposphere and lower stratosphere above the Canadian high Arctic. The amount of gravity wave activity in the stratosphere was found to be related to particular ...
James A. Whiteway
Questions and Answers - Does gravity affect atoms?
and Answers Main Index Next Question (Can you crush atoms?) Can you crush atoms? Does gravity affect atoms? Gravity affects atoms the same way it affects all other matter. Every...
A Coherent Strategy for Qauntum Gravity
Affine quantum gravity, which differs notably from either string theory or loop quantum gravity, is briefly reviewed. Emphasis in this article is placed on the use of affine coherent states in this program.
New models of f(R) theories of gravity
We introduce new models of f(R) theories of gravity that are a generalization of Horava-Lifshitz gravity.
Kluson, J. [Department of Theoretical Physics and Astrophysics, Faculty of Science, Masaryk University, Kotlarska 2, 611 37, Brno (Czech Republic)
New Models of f(R) Theories of Gravity
We introduce new models of f(R) theories of gravity that are generalization of Horava-Lifshitz gravity.
J. Kluson
Kluson, J
Unification of Gravity and Electromagnetism Revisited
Unification of gravity and electromagnetism based on a theory with an affine non-symmetric connection $\\Gamma^\\lambda_{\\mu\
Partha Ghose
A gravity term from spontaneous symmetry breaking
In this model, the gravity term in the Lagrangean comes from spontaneous symmetry breaking of an additional scalar quadruplet field $\\Upsilon$. The resulting gravitational field is approximate to one of the models of coframe gravity with parameters $\\rho_1 + 4 \\rho_2 = 0$, $\\rho_3 = 0$. This article includes an exact solution of coframe gravity with model parameters $\\rho_1 \
Mihai Moise
Gravity Transform for Input Conditioning in
Gravity Transform for Input Conditioning in Brain Machine Interfaces António R. C. Paiva, José C. Motivation 2. Methods i. Gravity Transform ii. Modeling and output sensitivity analysis 3. Data Analysis #12;3 Outline 1. Motivation 2. Methods i. Gravity Transform ii. Modeling and output sensitivity analysis 3. Data
Paiva, António R. C.
Survey Statisticians
U.S. Energy Information Administration (EIA) Indexed Site
Survey Statisticians Survey Statisticians The U.S.Energy Information Administration (EIA) within the Department of Energy has forged a world-class information program that stresses quality, teamwork, and employee growth. In support of our program, we offer a variety of profes- sional positions, including the Survey Statistician, who measures the amounts of energy produced and consumed in the United States. Responsibilities: Survey Statisticians perform or participate in one or more of the following important functions: * Design energy surveys by writing questions, creating layouts and testing questions for clarity and accuracy. * Conduct energy surveys to include sending out and tracking survey responses, editing and analyzing data submis- sions and communicating with respondents to verify data.
The detection of low-energy Quantum Gravity fluctuations with entangled states
We propose a thought experiment to detect low-energy Quantum Gravity phenomena using Quantum Optical Information Technologies. Gravitational field perturbations, such as gravitational waves and quantum gravity fluctuations, decohere the entangled photon pairs, revealing the presence of gravitational field fluctuations including those more speculative sources such as compact extra dimensions and the sub-millimetric hypothetical low-energy quantum gravity phenomena and then set a limit for the decoherence of photon bunches and entangled pairs in space detectable with the current astronomical space technology.
Tamburini, Fabrizio
Fabrizio Tamburini
GRAVITY: The adaptive optics assisted, two object beam combiner for the VLTI
We present the adaptive optics assisted, near-infrared VLTI instrument - GRAVITY - for precision narrow-angle astrometry and interferometric phase referenced imaging of faint objects. Precision astrometry and phase-referenced interferometric imaging will realize the most advanced vision of optical/infrared interferometry with the VLT. Our most ambitious science goal is to study motions within a few times the event horizon size of the Galactic Center massive black hole and to test General Relativity in its strong field limit. We define the science reference cases for GRAVITY and derive the top level requirements for GRAVITY. The installation of the instrument at the VLTI is planned for 2012.
S. Gillessen; G. Perrin; W. Brandner; C. Straubmeier; F. Eisenhauer; S. Rabien; A. Eckart; P. Lena; R. Genzel; T. Paumard; S. Hippler
Momentum Transport by Gravity Waves
The momentum flux by orographic gravity waves and the turbulent heat flux in wave-breaking regions are estimated from aircraft data from ALPEX. The fluxes on 6 March 1982 are controlled by low-level directional shear of the mean flow and ...
Jinwon Kim; L. Mahrt
High-gravity central stars
NLTE spectral analyses of high-gravity central stars by means of state-of-the-art model atmosphere techniques provide information about the precursor AGB stars. The hydrogen-deficient post-AGB stars allow investigations on the intershell matter which is apparently exhibited at the stellar surface. We summarize recent results from imaging, spectroscopy, and spectropolarimetry.
Thomas Rauch
Rheological measurements in reduced gravity
Rheology of fluidized beds and settling suspensions were studied experimentally in a series of reduced gravity parabolic flights aboard NASA�s KC?135 aircraft. Silica sands of two different size distributions were fluidized by air. The slurries were made using silica sand and Glycerol solution. The experimental set up incorporated instrumentation to measure the air flow rate
Sayavur I. Bakhtiyarov; Ruel A. Overfelt
Gravity and the Fermion Mass
It is shown that gravity generates mass for the fermion. It does so by coupling directly with the spinor field. The coupling term is invariant with respect to the electroweak gauge group $ U(1) \\otimes SU(2)_L. $ It replaces the fermion mass term $ m\\bar{\\psi} \\psi $.
Kenneth Dalton
Fundamental decoherence in quantum gravity
A recently introduced discrete formalism allows to solve the problem of time in quantum gravity in a relational manner. Quantum mechanics formulated with a relational time is not exactly unitary and implies a fundamental mechanism for decoherence of quantum states. The mechanism is strong enough to render the black hole information puzzle unobservable.
Rodolfo Gambini; Rafael Porto; Jorge Pullin
Spin-Gauge Theory of Gravity with Higgs-field Mechanism
We propose a Lorentz-covariant Yang-Mills spin-gauge theory, where the function valued Dirac matrices play the role of a non-scalar Higgs-field. As symmetry group we choose $SU(2) \\times U(1)$. After symmetry breaking a non-scalar Lorentz-covariant Higgs-field gravity appears, which can be interpreted within a classical limit as Einstein's metrical theory of gravity, where we restrict ourselves in a first step to its linearized version.
H. Dehnen; E. Hitzer
Spacetime Structure of an Evaporating Black Hole in Quantum Gravity
The impact of the leading quantum gravity effects on the dynamics of the Hawking evaporation process of a black hole is investigated. Its spacetime structure is described by a renormalization group improved Vaidya metric. Its event horizon, apparent horizon, and timelike limit surface are obtained taking the scale dependence of Newton's constant into account. The emergence of a quantum ergosphere is discussed. The final state of the evaporation process is a cold, Planck size remnant.
Bonanno, A
On model selection forecasting, Dark Energy and modified gravity
The Fisher matrix approach (Fisher 1935) allows one to calculate in advance how well a given experiment will be able to estimate model parameters, and has been an invaluable tool in experimental design. In the same spirit, we present here a method to predict how well a given experiment can distinguish between different models, regardless of their parameters. From a Bayesian viewpoint, this involves computation of the Bayesian evidence. In this paper, we generalise the Fisher matrix approach from the context of parameter fitting to that of model testing, and show how the expected evidence can be computed under the same simplifying assumption of a gaussian likelihood as the Fisher matrix approach for parameter estimation. With this `Laplace approximation' all that is needed to compute the expected evidence is the Fisher matrix itself. We illustrate the method with a study of how well upcoming and planned experiments should perform at distinguishing between Dark Energy models and modified gravity theories. In particular we consider the combination of 3D weak lensing, for which planned and proposed wide-field multi-band imaging surveys will provide suitable data, and probes of the expansion history of the Universe, such as proposed supernova and baryonic acoustic oscillations surveys. We find that proposed large-scale weak lensing surveys from space should be able readily to distinguish General Relativity from modified gravity models.
A. F. Heavens; T. D. Kitching; L. Verde
Schrodinger-like (Dilaton-)Gravity
We investigate possibilities for the Schrodinger-like gravity with the dynamical critical exponent z=2, where the action only contains the first-order time derivative. The Horava gravity always admits such a relevant deformation because the full (d+1) dimensional diffeomorphism of the Einstein gravity is replaced by the foliation preserving diffeomorphism. The dynamics is locally trivial or topological for the pure gravity case, but we can construct a dynamical field theory with z=2 dispersion relation by introducing a dilaton degree of freedom. Our model gives birth to a new model for quantum (dilaton-)gravity which may be applied to a membrane quantization.
Nakayama, Yu
Precision leveling and gravity studies at the Roosevelt Hot Springs KGRA, Utah. Final report: Volume 77-9
The objective of the precision leveling and gravity surveys in the Roosevelt Hot Springs KGRA, Utah, is to provide a baseline for detecting mass reduction or movement (displacement) related to injection or withdrawal of geofluids or to changes in tectonic strain, or both of these effects. The precision leveling and gravity data obtained during the period September 1975 through October 31, 1977 are presented, and interpretations of the data are made. (MHR)
Cook, K.L.; Carter, J.A.
Digital Surveying Directional Surveying Specialists | Open Energy
Digital Surveying Directional Surveying Specialists Digital Surveying Directional Surveying Specialists Jump to: navigation, search OpenEI Reference LibraryAdd to library Web Site: Digital Surveying Directional Surveying Specialists Author Directional Surveying Specialists Published Publisher Not Provided, 2012 DOI Not Provided Check for DOI availability: http://crossref.org Online Internet link for Digital Surveying Directional Surveying Specialists Citation Directional Surveying Specialists. Digital Surveying Directional Surveying Specialists [Internet]. 2012. [cited 2013/10/08]. Available from: http://www.digitalsurveying.co.za/services/geophysical-borehole-surveying/overview/optical-televiewer/ Retrieved from "http://en.openei.org/w/index.php?title=Digital_Surveying_Directional_Surveying_Specialists&oldid=690244"
Observational signatures of Jordan-Brans-Dicke theories of gravity
We analyze the Jordan-Brans-Dicke model (JBD) of gravity, where deviations from General Relativity (GR) are described by a scalar field non-minimally coupled to gravity. The theory is characterized by a constant coupling parameter, $\\omega_{\\rm JBD}$; GR is recovered in the limit $\\omega_{\\rm JBD} \\to \\infty$. In such theories, gravity modifications manifest at early times, so that one cannot rely on the usual approach of looking for inconsistencies in the expansion history and perturbations growth in order to discriminate between JBD and GR. However, we show that a similar technique can be successfully applied to early and late times observables instead. Cosmological parameters inferred extrapolating early-time observations to the present will match those recovered from direct late-time observations only if the correct gravity theory is used. We use the primary CMB, as will be seen by the Planck satellite, as the early-time observable; and forthcoming and planned Supernov{\\ae}, Baryonic Acoustic Oscillations and Weak Lensing experiments as late-time observables. We find that detection of values of $\\omega_{\\rm JBD}$ as large as 500 and 1000 is within reach of the upcoming (2010) and next-generation (2020) experiments, respectively.
Viviana Acquaviva; Licia Verde
Studies of strong-field gravity : testing the black hole hypothesis and investigating spin-curvature coupling
Observations of gravitational systems agree well with the predictions of general relativity (GR); however, to date we have only tested gravity in the weak-field limit. In the next few years, observational advances may make ...
Vigeland, Sarah Jane
The Dark Gravity model predictions for Gravity Probe B
The previous version of this article gave erroneous predictions. The correct uptodate predictions can be found in the section devoted to gravitomagnetism in the living review of the Dark Gravity theory: gr-qc/0610079 The most natural prediction is zero frame dragging and the same geodetic effect as predicted by GR. However, a straightforward extension of the theory could lead to the same frame-dragging as in GR.
Frederic Henry-Couannier
SCO Survey
Survey on Future of NIST's Standards Information Services. June 5, 2013. *. Bookmark and Share. Contact: Clare Allocca 301-975-4359. ...
Robotic Surveying
ZAPATA ENGINEERING challenged our engineers and scientists, which included robotics expertise from Carnegie Mellon University, to design a solution to meet our client's requirements for rapid digital geophysical and radiological data collection of a munitions test range with no down-range personnel. A prime concern of the project was to minimize exposure of personnel to unexploded ordnance and radiation. The field season was limited by extreme heat, cold and snow. Geographical Information System (GIS) tools were used throughout this project to accurately define the limits of mapped areas, build a common mapping platform from various client products, track production progress, allocate resources and relate subsurface geophysical information to geographical features for use in rapidly reacquiring targets for investigation. We were hopeful that our platform could meet the proposed 35 acres per day, towing both a geophysical package and a radiological monitoring trailer. We held our breath and crossed our fingers as the autonomous Speedrower began to crawl across the playa lakebed. We met our proposed production rate, and we averaged just less than 50 acres per 12-hour day using the autonomous platform with a path tracking error of less than +/- 4 inches. Our project team mapped over 1,800 acres in an 8-week (4 days per week) timeframe. The expertise of our partner, Carnegie Mellon University, was recently demonstrated when their two autonomous vehicle entries finished second and third at the 2005 Defense Advanced Research Projects Agency (DARPA) Grand Challenge. 'The Grand Challenge program was established to help foster the development of autonomous vehicle technology that will some day help save the lives of Americans who are protecting our country on the battlefield', said DARPA Grand Challenge Program Manager, Ron Kurjanowicz. Our autonomous remote-controlled vehicle (ARCV) was a modified New Holland 2550 Speedrower retrofitted to allow the machine-actuated functions to be controlled by an onboard computer. The computer-controlled Speedrower was developed at Carnegie Mellon University to automate agricultural harvesting. Harvesting tasks require the vehicle to cover a field using minimally overlapping rows at slow speeds in a similar manner to geophysical data acquisition. The Speedrower had demonstrated its ability to perform as it had already logged hundreds of acres of autonomous harvesting. This project is the first use of autonomous robotic technology on a large-scale for geophysical surveying.
Suzy Cantor-McKinney; Michael Kruzic
Survey Design Surveys were conducted using an Aero Commander 690A at a speed of 110
and exploratory tracklines. (see Rone et al. aerial survey poster) Sonobuoy deployments were incorporated whale detections. After considering limitations encountered during the aerial survey that year (iSurvey Design Surveys were conducted using an Aero Commander 690A at a speed of 110 knots and 1000
Survey Consumption
fsidentoi fsidentoi Survey Consumption and 'Expenditures, April 1981 March 1982 Energy Information Administration Wasningtoa D '" N """"*"""*"Nlwr. . *'.;***** -. Mik>. I This publication is available from ihe your COr : 20585 Residential Energy Consumption Survey: Consum ption and Expendi tures, April 1981 Through March 1982 Part 2: Regional Data Prepared by: Bruce Egan This report was prepared by the Energy Information Administra tion, the independent statistical
Massless Limit of Gravitational Higgs Mechanism
In gravitational Higgs mechanism graviton components acquire mass via spontaneous diffeomorphism breaking by scalar vacuum expectation values. We point out that in the massless limit the resulting theory is not Einstein-Hilbert gravity (EHG) but constrained gravity (CG). Consequently, massive solutions in the massless limit must be compared to those in CG (as opposed to EHG). We discuss spherically symmetric solutions in this context. The Schwarzschild solution in EHG can be coordinate-transformed such that it is also a solution in CG. The resulting solutions are non-perturbative in the asymptotic regime, and are reproduced in the massless limit of asymptotic massive solutions, hence no van Dam-Veltman-Zakharov discontinuity. We point out that higher curvature terms must be included to obtain non-singular spherically symmetric massive solutions and discuss a suitable framework.
Zurab Kakushadze
Dark Energy and Dark Gravity
Observations provide increasingly strong evidence that the universe is accelerating. This revolutionary advance in cosmological observations confronts theoretical cosmology with a tremendous challenge, which it has so far failed to meet. Explanations of cosmic acceleration within the framework of general relativity are plagued by difficulties. General relativistic models are nearly all based on a dark energy field with fine-tuned, unnatural properties. There is a great variety of models, but all share one feature in common -- an inability to account for the gravitational properties of the vacuum energy. Speculative ideas from string theory may hold some promise, but it is fair to say that no convincing model has yet been proposed. An alternative to dark energy is that gravity itself may behave differently from general relativity on the largest scales, in such a way as to produce acceleration. The alternative approach of modified gravity (or dark gravity) provides a new angle on the problem, but also faces serious difficulties, including in all known cases severe fine-tuning and the problem of explaining why the vacuum energy does not gravitate. The lack of an adequate theoretical framework for the late-time acceleration of the universe represents a deep crisis for theory -- but also an exciting challenge for theorists. It seems likely that an entirely new paradigm is required to resolve this crisis.
Ruth Durrer; Roy Maartens
Dynamical 3-Space: Emergent Gravity
The laws of gravitation devised by Newton, and by Hilbert and Einstein, have failed many experimental and observational tests, namely the bore hole g anomaly, flat rotation curves for spiral galaxies, supermassive black hole mass spectrum, uniformly expanding universe, cosmic filaments, laboratory G measurements, galactic EM bending, precocious galaxy formation,.. The response has been the introduction of the new epicycles: ``dark matter", ``dark energy", and others. To understand gravity we must restart with the experimental discoveries by Galileo, and following a heuristic argument we are led to a uniquely determined theory of a dynamical 3-space. That 3-space exists has been missed from the beginning of physics, although it was 1st directly detected by Michelson and Morley in 1887. Uniquely generalising the quantum theory to include this dynamical 3-space we deduce the response of quantum matter and show that it results in a new account of gravity, and explains the above anomalies and others. The dynamical theory for this 3-space involves G, which determines the dissipation rate of space by matter, and alpha, which experiments and observation reveal to be the fine structure constant. For the 1st time we have a comprehensive account of space and matter and their interaction - gravity.
Reginald T Cahill
Energy-momentum complexes in f(R) theories of gravity
Despite the fact that modified theories of gravity, in particular the f(R) gravity models have attracted much attention in the last years, the problem of the energy localization in the framework of these models has not been addressed. In the present work the concept of energy-momentum complexes is presented in this context. For the case of the Schwarzschild-de Sitter black hole solution of f(R) gravity the Landau-Lifshitz prescription is employed. In the limiting case where f(R) equals the Ricci scalar, the energy-momentum complex of the Schwarzschild-de Sitter black hole is equal to that derived in the framework of General Relativity. Furthermore, the energy-momentum complexes of widely used models of f(R) gravity for which the Schwarzschild-de Sitter black hole metric is a special case are computed in the Landau-Lifshitz prescription.
Multamaki, Tuomas; Vagenas, Elias C; Vilja, Iiro
Climate Survey
Operations Employee Operations Employee Climate Survey March 2009 Acknowledgements The Berkeley Lab Survey Team consisted of the following: Jim Krupnick, Sponsor Vera Potapenko, Project Lead Karen Ramorino, Project Manager Chris Paquette, MOR Associates Alexis Bywater, MOR Associates MOR Associates, an external consulting firm, acted as project manager for this effort, analyzing the data and preparing this report. MOR Associates specializes in continuous improve- ment, strategic thinking and leadership development. MOR Associates has conducted a number of large-scale surveys for organizations in higher education, including MIT, Stanford, the University of Chicago, and others. MOR Associates, Inc. 462 Main Street, Suite 300 Watertown, MA 02472 tel: 617.924.4501
Spectral Estimates of Gravity Wave Energy and Momentum Fluxes. Part III: Gravity Wave-Tidal Interactions
An application of the gravity wave parameterization scheme developed in the companion papers by Fritts and VanZandt and Fritts and Lu to the mutual interaction of gravity waves and tidal motions is presented. The results suggest that interaction ...
Wentong Lu; David C. Fritts
Static solutions for fourth order gravity
The Lichnerowicz and Israel theorems are extended to higher order theories of gravity. In particular it is shown that Schwarzschild is the unique spherically symmetric, static, asymptotically flat, black-hole solution, provided the spatial curvature is less than the quantum gravity scale outside the horizon. It is then shown that in the presence of matter (satisfying certain positivity requirements), the only static and asymptotically flat solutions of general relativity that are also solutions of higher order gravity are the vacuum solutions.
Nelson, William [Institute of Gravitation and the Cosmos, Penn State University, State College, Pennsylvania 16801 (United States)
Quantum Gravity: Has Spacetime Quantum Properties?
The incompatibility between GR and QM is generally seen as a sufficient motivation for the development of a theory of Quantum Gravity. If - so a typical argumentation - QM gives a universally valid basis for the description of all natural systems, then the gravitational field should have quantum properties. Together with the arguments against semi-classical theories of gravity, this leads to a strategy which takes a quantization of GR as the natural avenue to Quantum Gravity. And a quantization of the gravitational field would in some sense correspond to a quantization of geometry. Spacetime would have quantum properties. But, this strategy will only be successful, if gravity is a fundamental interaction. - What, if gravity is instead an intrinsically classical phenomenon? Then, if QM is nevertheless fundamentally valid, gravity can not be a fundamental interaction. An intrinsically classical gravity in a quantum world would have to be an emergent, induced or residual, macroscopic effect, caused by other interactions. The gravitational field (as well as spacetime) would not have any quantum properties. A quantization of GR would lead to artifacts without any relation to nature. The serious problems of all approaches to Quantum Gravity that start from a direct quantization of GR or try to capture the quantum properties of gravity in form of a 'graviton' dynamics - together with the, meanwhile, rich spectrum of approaches to an emergent gravity and/or spacetime - make this latter option more and more interesting for the development of a theory of Quantum Gravity. The most advanced emergent gravity (and spacetime) scenarios are of an information-theoretical, quantum-computational type.
Reiner Hedrich
Simultaneous measurement of gravity acceleration and gravity gradient with an atom interferometer
We demonstrate a method to measure the gravitational acceleration with a dual cloud atom interferometer; the use of simultaneous atom interferometers reduces the effect of seismic noise on the gravity measurement. At the same time, the apparatus is capable of accurate measurements of the vertical gravity gradient. The ability to determine the gravity acceleration and gravity gradient simultaneously and with the same instrument opens interesting perspectives in geophysical applications.
Sorrentino, F.; Lien, Y.-H.; Rosi, G.; Tino, G. M. [Dipartimento di Fisica e Astronomia and LENS, Universita di Firenze, INFN Sezione di Firenze, via Sansone 1, I-50019 Sesto Fiorentino (Italy); Bertoldi, A. [Laboratoire Charles Fabry de l'Institut d'Optique, CNRS and Universite Paris-Sud Campus Polytechnique, RD 128, F-91127 Palaiseau cedex (France); Bodart, Q. [Dipartimento di Fisica e Astronomia and LENS, Universita di Firenze, INFN Sezione di Firenze, via Sansone 1, I-50019 Sesto Fiorentino (Italy); European Space Agency, Research and Scientific Support Department, Keplerlaan 1, 2201 AZ Noordwijk (Netherlands); Cacciapuoti, L. [European Space Agency, Research and Scientific Support Department, Keplerlaan 1, 2201 AZ Noordwijk (Netherlands); Angelis, M. de [Istituto di Fisica Applicata 'Nello Carrara' CNR, via Madonna del Piano 10, I-50019 Sesto Fiorentino (Italy); Prevedelli, M. [Dipartimento di Fisica dell'Universita di Bologna, Via Irnerio 46, I-40126, Bologna (Italy)
Lovelock gravity is equivalent to Einstein gravity coupled to form fields
Lovelock gravity is a class of higher-derivative gravitational theories whose linearized equations of motion have no more than two time derivatives. Here, it is shown that any Lovelock theory can be effectively described as Einstein gravity coupled to a p-form gauge field. This extends the known example of an f(R) theory of gravity, which can be described as Einstein gravity coupled to a scalar field.
Brustein, Ram
Gravity Gold Concentration at Newmont Mining
Abstract Scope, The process of gold recovery by gravity concentration is incorporated ... Energy Management Planning, Following the ISO 50001 Draft Standard.
Optimising Circuit Design for Gravity Gold Recovery
Abstract Scope, To determine the optimal circuit configuration for gravity gold recovery ... Energy Management Planning, Following the ISO 50001 Draft Standard.
Thermophysical Property Measurements Under Reduced Gravity ...
Presentation Title, Thermophysical Property Measurements Under Reduced Gravity Conditions: Evolution and Status of theThermoLab Project. Author(s), H-J
Gravity from the extension of spatial diffeomorphisms
The possibility of the extension of spatial diffeomorphisms to a larger family of symmetries in a class of classical field theories is studied. The generator of the additional local symmetry contains a quadratic kinetic term and a potential term which can be a general (not necessarily local) functional of the metric. From the perspective of the foundation of Einstein's gravity our results are positive: The extended constraint algebra is either that of Einstein's gravity, or ultralocal gravity. If our goal is a simple modification of Einstein's gravity that for example makes it perturbatively renormalizable, as has recently been suggested, then our results show that there is no such theory within this class.
Szilard Farkas; Emil J. Martinec
Palatini formulation of L(R) gravity
We review the Palatini formulation of the higher-derivative gravity of the $L(R)$ form and its applications in cosmology.
Peng Wang; Xin-He Meng
VLBI surveys
Systematic surveys of astronomical objects often lead to discoveries, but always provide invaluable information for statistical studies of well-defined samples. They also promote follow-up investigations of individual objects or classes. Surveys using a yet unexplored observing wavelength, a novel technique or a new instrument are of special importance. Significantly improved observing parameters (e.g. sensitivity, angular resolution, monitoring capability) provide new insight into the morphological and physical properties of the objects studied. I give a brief overview of the important Very Long Baseline Interferometry (VLBI) imaging surveys conducted in the past. A list of surveys guides us through the developments up until the present days. I also attempt to show directions for the near future.
S. Frey
Universality in Pure Gravity Mediation
If low energy supersymmetry is realized in nature, the apparent discovery of a Higgs boson with mass around 125 GeV points to a supersymmetric mass spectrum in the TeV or multi-TeV range. Multi-TeV scalar masses are a necessary component of supersymmetric models with pure gravity mediation or in any model with strong moduli stabilization. Here, we show that full scalar mass universality remains viable as long as the ratio of Higgs vevs, tan beta is relatively small (\\lesssim 2.5). We discuss in detail the low energy (observable) consequences of these models.
Jason L. Evans; Masahiro Ibe; Keith A. Olive; Tsutomu T. Yanagida
Quantum Geometry and Quantum Gravity
The purpose of this contribution is to give an introduction to quantum geometry and loop quantum gravity for a wide audience of both physicists and mathematicians. From a physical point of view the emphasis will be on conceptual issues concerning the relationship of the formalism with other more traditional approaches inspired in the treatment of the fundamental interactions in the standard model. Mathematically I will pay special attention to functional analytic issues, the construction of the relevant Hilbert spaces and the definition and properties of geometric operators: areas and volumes.
J. Fernando Barbero G.
The Opening of the Tasman Sea: A Gravity Anomaly Animation
The first plate tectonic gravity anomaly grid animation using data from the Tasman Sea is presented. In this animation the tectonic elements are represented by their respective gravity fields, based on recent marine-satellite-derived gravity ...
C. Gaina; R. D. M�ller; W. R. Roest; P. Symonds
wissen zwar, wie man Gravitationskrfte berechnet, aber wir wissen nicht, wie man Gravitation in das mathematische Gebude der Quantentheorie des Standardmodells einbauen kann....
Gravedad Avanzar Volver Principal ESTOY PERDIDO La fuerza gravitacional es quizs la fuerza ms familiar para nosotros, pero no est includa en el Modelo Standard, porque...
das Farb-Kraftfeld, das entsteht, wenn sich das b Quark vom b Antiquark trennt, ignoriert. Diese Energie wandelt sich in ein weiteres Quark-Antiquark Paar um; was zur Emission...
Searching for modified gravity with baryon oscillations: from SDSS to wide field multiobject spectroscopy (WFMOS)
We discuss how the baryon acoustic oscillation (BAO) signatures in the galaxy power spectrum can distinguish between modified gravity and the cosmological constant as the source of cosmic acceleration. To this end we consider a model characterized by a parameter $n$, which corresponds to the Dvali-Gabadadze-Porrati (DGP) model if $n=2$ and reduces to the standard spatially flat cosmological constant concordance model for $n$ equal to infinity. We find that the different expansion histories of the modified gravity models systematically shifts the peak positions of BAO. A preliminary analysis using the current SDSS LRG sample indicates that the original DGP model is disfavored unless the matter density parameter exceeds 0.3. The constraints will be strongly tightened with future spectroscopic samples of galaxies at high redshifts. We demonstrate that WFMOS, in collaboration with other surveys such as Planck, will powerfully constrain modified gravity alternatives to dark energy as the explanation of cosmic acceleration.
Kazuhiro Yamamoto; Bruce A. Bassett; Robert C. Nichol; Yasushi Suto; Kazuhiro Yahata
Laundered protective clothing survey
It is considered appropriate occasionally to make independent checks on the effectiveness of the plant laundry in removing radioactive contamination from plant-issue protective clothing. Previous surveys have offered constructive criticism resulting in improved handling of high level and soft beta contaminated clothing and incorporation in new designs of ventilating and air sampling recommendations. Recurrently the adequacy of laundry reject limits is questioned, and only recently an accurate, special study resulted in relaxed limits for Metal Preparation area clothing. A current question concerns the advisability of determining the reject level on the beta-gamma monitor more frequently than once a day. 2 tabs.
Clukey, H.V.
Gravity in Complex Hermitian Space-Time
A generalized theory unifying gravity with electromagnetism was proposed by Einstein in 1945. He considered a Hermitian metric on a real space-time. In this work we review Einstein's idea and generalize it further to consider gravity in a complex Hermitian space-time.
Ali H. Chamseddine
Scale-Free Growing Networks and Gravity
We propose a possible relation between complex networks and gravity. Our guide in our proposal is the power-law distribution of the node degree in network theory and the information approach to gravity. The established bridge may allow us to carry geometric mathematical structures, which are considered in gravitational theories, to probabilistic aspects studied in the framework of complex networks and vice versa.
J. A. Nieto
Mechanical Properties of Counter-gravity Cast IN718
Key Words: Counter-gravity, investment casting, superalloys, IN718, inert ... using the Counter-gravity Low-pressure Inert-atmosphere (CLI) investment casting�...
Rainbow gravity and scale-invariant fluctuations
We re-examine a recently proposed scenario where the deformed dispersion relations associated with a flow of the spectral dimension to a UV value of 2 leads to a scale-invariant spectrum of cosmological fluctuations, without the need for inflation. In that scenario Einstein gravity was assumed. The theory displays a wavelength-dependent speed of light but by transforming to a suitable "rainbow frame" this feature can be removed, at the expense of modifying gravity. We find that the ensuing rainbow gravity theory is such that gravity switches off at high energy (or at least leads to a universal conformal coupling). This explains why the fluctuations are scale-invariant on all scales: there is no horizon scale as such. For dispersion relations that do not lead to exact scale invariance we find instead esoteric inflation in the rainbow frame. We argue that these results shed light on the behaviour of gravity under the phenomenon of dimensional reduction.
Giovanni Amelino-Camelia; Michele Arzano; Giulia Gubitosi; Joao Magueijo
Solar System constraints to nonminimally coupled gravity
We extend the analysis of Chiba, Smith and Erickcek \\cite{CSE} of Solar System constraints on $f(R)$ gravity to a class of nonminimally coupled (NMC) theories of gravity. These generalize $f(R)$ theories by replacing the action functional of General Relativity (GR) with a more general form involving two functions $f^1(R)$ and $f^2(R)$ of the Ricci scalar curvature $R$. While the function $f^1(R)$ is a nonlinear term in the action, analogous to $f(R)$ gravity, the function $f^2(R)$ yields a NMC between the matter Lagrangian density $\\LL_m$ and the scalar curvature. The developed method allows for obtaining constraints on the admissible classes of functions $f^1(R)$ and $f^2(R)$, by requiring that predictions of NMC gravity are compatible with Solar System tests of gravity. We apply this method to a NMC model which accounts for the observed accelerated expansion of the Universe.
Orfeu Bertolami; Riccardo March; Jorge P�ramos
OBSERVING GRAVITATIONAL LENSING EFFECTS BY Sgr A* WITH GRAVITY
The massive black hole Sgr A* at the Galactic center is surrounded by a cluster of stars orbiting around it. Light from these stars is bent by the gravitational field of the black hole, giving rise to several phenomena: astrometric displacement of the primary image, the creation of a secondary image that may shift the centroid of Sgr A*, and magnification effects on both images. The soon-to-be second-generation Very Large Telescope Interferometer instrument GRAVITY will perform observations in the near-infrared of the Galactic center at unprecedented resolution, opening the possibility of observing such effects. Here we investigate the observability limits for GRAVITY of gravitational lensing effects on the S-stars in the parameter space 1[D{sub LS}, {gamma}, K], where D{sub LS} is the distance between the lens and the source, {gamma} is the alignment angle of the source, and K is the source's apparent magnitude in the K band. The easiest effect to observe in future years is the astrometric displacement of primary images. In particular, the shift of the star S17 from its Keplerian orbit will be detected as soon as GRAVITY becomes operative. For exceptional configurations, it will be possible to detect effects related to the spin of the black hole or post-Newtonian orders in the deflection.
Bozza, V. [Department of Physics 'E.R. Caianiello', University of Salerno, Via Ponte Don Melillo, Fisciano I-84084 (Italy); Mancini, L., E-mail: firstname.lastname@example.com, E-mail: email@example.com [Max Planck Institute for Astronomy, Koenigstuhl 17, D-69117 Heidelberg (Germany)
We introduce the Minimum Entropy Method, a simple statistical technique for constraining the Milky Way gravitational potential and simultaneously testing different gravity theories directly from 6D phase-space surveys and without adopting dynamical models. We demonstrate that orbital energy distributions that are separable (i.e., independent of position) have an associated entropy that increases under wrong assumptions about the gravitational potential and/or gravity theory. Of known objects, 'cold' tidal streams from low-mass progenitors follow orbital distributions that most nearly satisfy the condition of separability. Although the orbits of tidally stripped stars are perturbed by the progenitor's self-gravity, systematic variations of the energy distribution can be quantified in terms of the cross-entropy of individual tails, giving further sensitivity to theoretical biases in the host potential. The feasibility of using the Minimum Entropy Method to test a wide range of gravity theories is illustrated by evolving restricted N-body models in a Newtonian potential and examining the changes in entropy introduced by Dirac, MONDian, and f(R) gravity modifications.
Penarrubia, Jorge [Instituto de Astrofisica de Andalucia-CSIC, Glorieta de la Astronomia s/n, E-18008 Granada (Spain); Koposov, Sergey E. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge, CB3 0HA (United Kingdom); Walker, Matthew G., E-mail: email@example.com [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States)
Spontaneously Induced Gravity: From Rippled Dark Matter to Einstein Corpuscles
Suppose General Relativity, provocatively governed by a dimensional coupling constant, is a spontaneously induced theory of Gravity. Invoking Zee's mechanism, we represent the reciprocal Newton constant by a Brans Dicke scalar field, and let it damped oscillating towards its General Relativistic VEV. The corresponding cosmological evolution, in the Jordan frame, averagely resembles the familiar dark radiation -> dark matter -> dark energy domination sequence. The fingerprints of the theory are fine ripples, hopefully testable, in the FRW scale factor; they die away at the strict General Relativity limit. Also derived is the spherically symmetric static configuration associated with spontaneously induced General Relativity. At the stiff scalar potential limit, the exterior Schwarzschild solution is recovered. However, due to level crossing at the would have been horizon, it now connects with a novel dark core characterized by a locally varying Newton constant. The theory further predicts light Einstein-style gravitational corpuscles (elementary particles?) which become point-like at the GR-limit.
Aharon Davidson; Ilya Gurwich
The Lightest Higgs Boson Mass in Pure Gravity Mediation Model
We discuss the lightest Higgs boson mass in the minimal supersymmetric Standard Model with "pure gravity mediation". By requiring that the model provides the observed dark matter density, we find that the lightest Higgs boson is predicted to be below 132GeV. We also find that the upper limit on the lightest Higgs boson mass becomes 128GeV, if we further assume thermal leptogenesis mechanism as the origin of baryon asymmetry of universe. The interrelations between the Higgs boson mass and the gaugino masses are also discussed.
Ibe, Masahiro
Nonlinear Fluid Dynamics from Gravity
Black branes in AdS5 appear in a four parameter family labeled by their velocity and temperature. Promoting these parameters to Goldstone modes or collective coordinate fields -- arbitrary functions of the coordinates on the boundary of AdS5 -- we use Einstein's equations together with regularity requirements and boundary conditions to determine their dynamics. The resultant equations turn out to be those of boundary fluid dynamics, with specific values for fluid parameters. Our analysis is perturbative in the boundary derivative expansion but is valid for arbitrary amplitudes. Our work may be regarded as a derivation of the nonlinear equations of boundary fluid dynamics from gravity. As a concrete application we find an explicit expression for the expansion of this fluid stress tensor including terms up to second order in the derivative expansion.
Sayantani Bhattacharyya; Veronika E Hubeny; Shiraz Minwalla; Mukund Rangamani
Thermodynamics in Modified Gravity Theories
We demonstrate that there does exist an equilibrium description of thermodynamics on the apparent horizon in the expanding cosmological background for a wide class of modified gravity theories with the Lagrangian density $f(R, \\phi, X)$, where $R$ is the Ricci scalar and $X$ is the kinetic energy of a scalar field $\\phi$. This comes from a suitable definition of an energy momentum tensor of the "dark" component obeying the local energy conservation law in the Jordan frame. It is shown that the equilibrium description in terms of the horizon entropy $S$ is convenient because it takes into account the contribution of the horizon entropy $\\hat{S}$ in non-equilibrium thermodynamics as well as an entropy production term.
Kazuharu Bamba; Chao-Qiang Geng; Shinji Tsujikawa
Non-Gaussian Stochastic Gravity
This paper presents a new, non-Gaussian formulation of stochastic gravity by incorporating the higher moments of the fluctuations of the quantum stress energy tensor for a free quantum scalar field in a consistent way. A scheme is developed for obtaining realizations of these fluctuations in terms of the Wightman function, and the behavior of the fluctuations is investigated. The resulting probability distribution for fluctuations of the energy density in Minkowski spacetime is found to be similar to a shifted Gamma distribution. This distribution features a minimum energy density cutoff at a small negative value, but a sharp peak in the vicinity of this cutoff such that the total probability of observing a negative value is approximately 62%, balanced by correspondingly larger but rarer positive values.
Jason D. Bates
Exact Solutions in Massive Gravity
Massive gravity is a good theoretical laboratory to study modifications of General Relativity. The theory offers a concrete set-up to study models of dark energy, since it admits cosmological self-accelerating solutions in the vacuum, in which the size of the acceleration depends on the graviton mass. Moreover, non-linear gravitational self-interactions, in the proximity of a matter source, manage to mimic the predictions of linearised General Relativity, hence agreeing with solar-system precision measurements. In this article, we review our work in the subject, classifying, on one hand, static solutions, and on the other hand, self-accelerating backgrounds. For what respects static solutions we exhibit black hole configurations, together with other solutions that recover General Relativity near a source via the Vainshtein mechanism. For the self-accelerating solutions we describe a wide class of cosmological backgrounds, including an analysis of their stability.
Gianmassimo Tasinato; Kazuya Koyama; Gustavo Niz
Emergent Horava gravity in graphene
First of all, we reconsider the tight - binding model of monolayer graphene, in which the variations of the hopping parameters are allowed. We demonstrate that the emergent 2D Weitzenbock geometry as well as the emergent U(1) gauge field appear. The emergent gauge field is equal to the linear combination of the components of the zweibein. Therefore, we actually deal with the gauge fixed version of the emergent 2+1 D teleparallel gravity. In particular, we work out the case, when the variations of the hopping parameters are due to the elastic deformations, and relate the elastic deformations with the emergent zweibein. Next, we investigate the tight - binding model with the varying intralayer hopping parameters for the multilayer graphene with the ABC stacking. In this case the emergent 2D Weitzenbock geometry and the emergent U(1) gauge field appear as well, the emergent low energy effective field theory has the anisotropic scaling.
G. E. Volovik; M. A. Zubkov
Dark Energy and Modified Gravity
Explanations of the late-time cosmic acceleration within the framework of general relativity are plagued by difficulties. General relativistic models are mostly based on a dark energy field with fine-tuned, unnatural properties. There is a great variety of models, but all share one feature in common -- an inability to account for the gravitational properties of the vacuum energy, and a failure to solve the so-called coincidence problem. Two broad alternatives to dark energy have emerged as candidate models: these typically address only the coincidence problem and not the vacuum energy problem. The first is based on general relativity and attempts to describe the acceleration as an effect of inhomogeneity in the universe. If this alternative could be shown to work, then it would provide a dramatic resolution of the coincidence problem; however, a convincing demonstration of viability has not yet emerged. The second alternative is based on infra-red modifications to general relativity, leading to a weakening of gravity on the largest scales and thus to acceleration. Most examples investigated so far are scalar-tensor or brane-world models, and we focus on the simplest candidates of each type: $f(R)$ models and DGP models respectively. Both of these provide a new angle on the problem, but they also face serious difficulties. However, investigation of these models does lead to valuable insights into the properties of gravity and structure formation, and it also leads to new strategies for testing the validity of General Relativity itself on cosmological scales.
We consider the prospects for measuring the pairwise kinetic Sunyaev-Zel'dovich (kSZ) signal from galaxy clusters discovered in large photometric surveys such as the Dark Energy Survey (DES). We project that the DES cluster sample will, in conjunction with existing mm-wave data from the South Pole Telescope (SPT), yield a detection of the pairwise kSZ signal at the 8{sigma}-13{sigma} level, with sensitivity peaking for clusters separated by {approx}100 Mpc distances. A next-generation version of SPT would allow for a 18{sigma}-30{sigma} detection and would be limited by variance from the kSZ signal itself and the residual thermal Sunyaev-Zel'dovich (tSZ) signal. Throughout our analysis, we assume photometric redshift errors that wash out the signal for clusters separated by {approx}<50 Mpc; a spectroscopic survey of the DES sample would recover this signal and allow for a 26{sigma}-43{sigma} detection, and would again be limited by kSZ/tSZ variance. Assuming a standard model of structure formation, these high-precision measurements of the pairwise kSZ signal will yield detailed information on the gas content of the galaxy clusters. Alternatively, if the gas can be sufficiently characterized by other means (e.g., using tSZ, X-ray, or weak lensing), then the relative velocities of the galaxy clusters can be isolated, thereby providing a precision measurement of gravity on 100 Mpc scales. We briefly consider the utility of these measurements for constraining theories of modified gravity.
Keisler, Ryan [Kavli Institute for Cosmological Physics, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637 (United States); Schmidt, Fabian, E-mail: email@example.com, E-mail: email@example.com [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08540 (United States)
On the extension of Jackiw's scalar theory to (2+1)- dimensional gravity
We study some aspects of three-dimensional gravity by extending Jackiw's scalar theory to (2+1)-dimensions and find a black hole solution. We show that in in general this teory does not possess a Newtonian limit except for special metric configurations.
V. B. Bezerra; J. Spinelly; C. Romero
Dark Energy from Brane-world Gravity
Summary. Recent observations provide strong evidence that the universe is accelerating. This confronts theory with a severe challenge. Explanations of the acceleration within the framework of general relativity are plagued by difficulties. General relativistic models require a �dark energy � field with effectively negative pressure. An alternative to dark energy is that gravity itself may behave differently from general relativity on the largest scales, in such a way as to produce acceleration. The alternative approach of modified gravity also faces severe difficulties, but does provide a new angle on the problem. This review considers an example of modified gravity, provided by brane-world models that self-accelerate at late times. 1 1
Roy Maartens
Consistent matter couplings for Plebanski gravity
We develop a scheme for the minimal coupling of all standard types of tensor and spinor field matter to Plebanski gravity. This theory is a geometric reformulation of vacuum general relativity in terms of two-form frames and connection one-forms, and provides a covariant basis for various quantization approaches. Using the spinor formalism we prove the consistency of the newly proposed matter coupling by demonstrating the full equivalence of Plebanski gravity plus matter to Einstein-Cartan gravity. As a by-product we also show the consistency of some previous suggestions for matter actions.
Tennie, Felix; Wohlfarth, Mattias N. R. [Zentrum fuer Mathematische Physik und II. Institut fuer Theoretische Physik, Universitaet Hamburg, Luruper Chaussee 149, 22761 Hamburg (Germany)
Gravity as BF theory plus potential
Spin foam models of quantum gravity are based on Plebanski's formulation of general relativity as a constrained BF theory. We give an alternative formulation of gravity as BF theory plus a certain potential term for the B-field. When the potential is taken to be infinitely steep one recovers general relativity. For a generic potential the theory still describes gravity in that it propagates just two graviton polarizations. The arising class of theories is of the type amenable to spin foam quantization methods, and, we argue, may allow one to come to terms with renormalization in the spin foam context.
Kirill Krasnov
Generalised Wick Transform in Dimensionally Reduced Gravity
In the context of canonical quantum gravity, we study an alternative real quantisation scheme, which is arising by relating simpler Riemannian quantum theory to the more complicated physical Lorentzian theory - the generalised Wick transform. On the symmetry reduced models, homogenous Bianchi cosmology and 2+1 gravity, we investigate its generalised construction principle, demonstrate that the emerging quantum theory is equivalent to the one obtained from standard quantisation and how to obtain physical states in Lorentzian gravity from Wick transforming solutions of Riemannian quantum theory.
B. Hartmann; J. Wisniewski
Ph.D.Thesis Binary inversion of gravity
Ph.D.Thesis Binary inversion of gravity data for salt imaging Richard A. Krahenbuhl Center for Gravity, Electrical & Magnetic Studies Colorado School of Mines Department of Geophysics Colorado School of gravity data for salt imaging Richard A. Krahenbuhl Center for Gravity, Electrical & Magnetic Studies
Texas Gulf Coast Refinery District API Gravity (Weighted ...
Texas Gulf Coast Refinery District API Gravity (Weighted Average) of Crude Oil Input to Refineries (Degree)
Minimum Experimental Standards in the Laboratory Search for Gravity Effects
Peer?reviewed reports of experimental modifications of gravity over rotating superconductors (Podkletnov
H. Reiss; G. Hathaway
Gravity and General Relativity at KCL D C Robinson
Gravity and General Relativity at KCL D C Robinson Mathematics Department King's College London Strand, London WC2R 2LS, UK. February 22, 2011 1 The study of gravity at KCL Research on gravity has been, an approach to New- tonian gravity similar to his field theory formulation of electromagnetism published
Bushnell, Colin J.
Gravity Recovery And Climate Experiment Hydrology, Earth Science and Climate
GRACE Gravity Recovery And Climate Experiment Hydrology, Earth Science and Climate Ole Baltazar of blood cell Delivers 10-Day / Monthly gravity field From 2002 Onwards Study gravity field changes | side 6 Range responds to Gravity #12;GRACE science results | 28. November 2007 | OA | side 7 Variations
Mosegaard, Klaus
Texas Gulf Coast Refinery District API Gravity (Weighted Average ...
Reduced Gravity Education Flight Opportunity for Students at Minority
Energy.gov (U.S. Department of Energy (DOE)) Indexed Site
Reduced Gravity Education Flight Opportunity for Students at Reduced Gravity Education Flight Opportunity for Students at Minority Serving Institutions Reduced Gravity Education Flight Opportunity for Students at Minority Serving Institutions March 21, 2013 - 5:21pm Addthis Reduced Gravity Education Flight Opportunity for Students at Minority Serving Institutions NASA is offering undergraduate students from Minority Serving Institutions an opportunity to test experiments in microgravity aboard NASA's reduced gravity aircraft. This opportunity is a partnership between the Minority University Research and Education Program and NASA's Reduced Gravity Education Flight Program, which gives aspiring explorers a chance to propose, design and fabricate a reduced-gravity experiment. Selected teams will test and evaluate their
Observations of a Mesoscale Ducted Gravity Wave
This paper reports coordinated observations of a mesoscale gravity wave made during the FRONTS 84 field experiment conducted in southwestern France in the summer of 1984. The observations were unique in the sense that all relevant wave ...
F. M. Ralph; V. Venkateswaran; M. Crochet
Filtering of Gravity Modes in Atmospheric Models
The impact of gravity modes in atmospheric model predictions is assessed quantitatively by comparing integrations with a normal mode initialized primitive equation model and its corresponding pseudogeostrophic form to document some generally ...
F. Baer; J. J. Tribbia
Stochastic Parameterization of Gravity Wave Stresses
Selective transmission of gravity waves into the upper mesosphere and lower thermosphere leads to the generation of mean flows opposite to those below. This interaction is addressed in the context of a simplified transient, stochastic, ...
Timothy J. Dunkerton
Inertia�Gravity Waves in the Stratosphere
The propagation and refraction of stationary inertia�gravity waves in the winter stratosphere is examined with ray tracing. Due to their smaller vertical group velocity these waves experience more lateral ray movement and horizontal refraction ...
Definition: Gravity Techniques | Open Energy Information
0521576326 Ret LikeLike UnlikeLike You like this.Sign Up to see what your friends like. rieved from "http:en.openei.orgwindex.php?titleDefinition:GravityTechniques&oldid598...
Quantum gravity and renormalization: The tensor track
We propose a new program to quantize and renormalize gravity based on recent progress on the analysis of large random tensors. We compare it briefly with other existing approaches.
Rivasseau, Vincent [Laboratoire de Physique Theorique, CNRS UMR 8627 Universite Paris-Sud, 91405 Orsay (France)
Energy conditions in f(R)-gravity
In order to shed some light on the current discussion about f(R)-gravity theories we derive and discuss the bounds imposed by the energy conditions on a general f(R) functional form. The null and strong energy conditions in this framework are derived from the Raychaudhuri's equation along with the requirement that gravity is attractive, whereas the weak and dominant energy conditions are stated from a comparison with the energy conditions that can be obtained in a direct approach via an effective energy-momentum tensor for f(R)-gravity. As a concrete application of the energy conditions to locally homogeneous and isotropic f(R)-cosmology, the recent estimated values of the deceleration and jerk parameters are used to examine the bounds from the weak energy condition on the parameters of two families of f(R)-gravity theories.
Santos, J; Rebou�as, M J; Carvalho, F C
Energy and Hamiltonian in first order gravity
In this work the definition of a quasilocal energy for four dimensional first order gravity is developed. Using this an action principle which is adequate for the canonical ensemble is obtained. The microcanonical action principle is obtained as well.
Rodrigo Aros
Probes of strong-field gravity
In this thesis, I investigate several ways to probe gravity in the strong-field regime. These investigations focus on observables from the gravitational dynamics, i.e. when time derivatives are large: thus I focus on sources ...
Stein, Leo Chaim
Observationally Verifiable Predictions of Modified Gravity
MOG is a fully relativistic modified theory of gravity based on an action principle. The MOG field equations are exactly solvable numerically in two important cases. In the spherically symmetric
J. W. Moffat; V. T. Toth
SUSY QM meets 5d Gravity
We report hidden quantum mechanical supersymmetry structure in five-dimensional gravity with the Randall-Sundrum background. We show that two N=2 supersymmetries are hidden in the spectrum.
Ohya, Satoshi
Dynamical Foundations of the Brane Induced Gravity
We present a comprehensive formalism to derive precise expressions for the induced gravity of the braneworld, assuming the dynamics of the Dirac-Nambu-Goto type. The quantum fluctuations of the brane at short distances give rise to divergences, which should be cutoff at the scale of the inverse thickness of the brane. It turns out that the induced-metric formula is converted into an Einstein-like equation via the quantum effects. We determine the coefficients of the induced cosmological and gravity terms, as well as those of the terms including the extrinsic curvature and the normal connection gauge field. The latter is the characteristic of the brane induced gravity theory, distinguished from ordinary none-brane induced gravity.
Keiichi Akama; Takashi Hattori
Shear Excitation of Atmospheric Gravity Waves
Unstable Velocity shears are a Common source of vertically propagating gravity waves in the atmosphere. However, the growth rates of unstable modes predicted by linear theory cannot always amount for their observed importance.
David C. Fritts
Earthlings : humanity's essential relationship with gravity
A realm of serious scientific questions about gravity's role in biology is being researched in labs around the world, from NASA's Dryden Research Laboratories in the Mohave Desert, to Japan's Radioisotope Center at the ...
Vargas Medina, Iris M�nica
Internal Gravity Wave Generation and Hydrodynamic Instability
Two mechanisms are proposed whereby internal gravity waves (IGW) may radiate from a linearly unstable region of Boussinesq parallel flow that is characterized in the far field by constant horizontal velocity and Brunt-V�is�l� frequency. Through ...
B. R. Sutherland; C. P. Caulfield; W. R. Peltier
Finite temperature R-squared quantum gravity
The quantum gravity path integral's measure can be written as the product of classical backgrounds and quantum fluctuations about each background. After proving that fluctuations about the background do not diffuse in Hilbert space and obey the laws of many-body statistics, their probability distributions, entropy, and expected background are determined. This background obeys expectation-valued Einstein equations and features an entropy-based positive cosmological constant. From the fluctuation probability distributions, a finite temperature, R-squared, quantum gravity path integral is constructed whose action presents an interaction picture of quantum gravity that `moves with' the expected background in Hilbert space. Within this interaction picture of quantum fluctuations about an expected background, the fields required to describe quantum gravity have been transformed into `ordinary' quantum fields propagating on this `rigid' or `fixed' expected background. Back-reaction has been fully accounted for, and the quantum formulation is manifestly background independent.
C. D. Burton
J. Santos; J. S. Alcaniz; M. J. Reboucas; F. C. Carvalho
Plasmon-graviton conversion in a magnetic field in TeV-scale gravity
Kaluza-Klein (KK) gravitons emission rates due to plasmon-graviton conversion in magnetic field are computed within the ADD model of TeV-scale gravity. Plasma is described in the kinetic approach as the system of charged particles and Maxwell field both confined on the brane. Interaction with multidimensional gravity living in the bulk with $n$ compact extra dimensions is introduced within the linearized theory. Plasma collective effects enter through the two-point correlation function of the fluctuations of the energy-momentum tensor. The estimate for magnetic stars is presented leading to the lower limit of the D-dimensional Plank mass.
Melkumova, E Yu
JOM Salary Survey - TMS
Towards Gravity-Gauge-Higgs Unification
We discuss a possibility to solve the gauge hierarchy problem in the framework of Gravity-Gauge-Higgs Unification scenario. We have calculated 1-loop correction to the mass of the scalar field, which is originated from 55-component of the metric, in five dimensional gravity theory with the bulk scalar field compactified on S^1. It is shown that the quadratic divergences are canceled and the finite mass is generated by explicit diagrammatic calculations and the effective potential calculations.
K. Hasegawa; C. S. Lim; Nobuhito Maru
Thermodynamics of space quanta models quantum gravity
Canonically quantized 3+1 general relativity with the global one dimensionality (1D) conjecture defines the model, which dimensionally reduced and secondary quantized yields the 1D quantum field theory wherein generic one-point correlations create physical scales. This simple quantum gravity model, however, can be developed in a wider sense. In this paper we propose to consider ab initio thermodynamics of space quanta as the quantum gravity phenomenology. The thermodynamics is constructed in the entropic formalism.
L. A. Glinka
Localizing gravity on exotic thick 3-branes
We consider localization of gravity on thick branes with a nontrivial structure. Double walls that generalize the thick Randall-Sundrum solution, and asymmetric walls that arise from a Z{sub 2} symmetric scalar potential, are considered. We present a new asymmetric solution: a thick brane interpolating between two AdS{sub 5} spacetimes with different cosmological constants, which can be derived from a 'fake supergravity' superpotential, and show that it is possible to confine gravity on such branes.
Castillo-Felisola, Oscar [Centro de Fisica Fundamental, Universidad de Los Andes, Merida (Venezuela); International Centre for Theoretical Physics, 34100 Trieste (Italy); Melfo, Alejandra; Pantoja, Nelson; Ramirez, Alba [Centro de Fisica Fundamental, Universidad de Los Andes, Merida (Venezuela)
Anti-gravity: The key to 21st century physics
The masses coupling constants and cosmological parameters obtained using our discrete and combinatorial physics based on discrimination between bit-strings indicate that we can achieve the unification of quantum mechanics with relativity which had become the goal of twentieth century physics. To broaden our case we show that limitations on measurement of the position and velocity of an individual massive particle observed in a colliding beam scattering experiment imply real, rational commutation relations between position and velocity. Prior to this limit being pushed down to quantum effects, the lower bound is set by the available technology, but is otherwise scale invariant. Replacing force by force per unit mass and force per unit charge allows us to take over the Feynman-Dyson proof of the Maxwell Equations and extend it to weak gravity. The crossing symmetry of the individual scattering processes when one or more particles are replaced by anti-particles predicts both Coulomb attraction (for charged particles) and a Newtonian repulsion between any particle and its anti-particle. Previous quantum results remain intact, and predict the expected relativistic fine structure and spin dependencies. Experimental confirmation of this anti-gravity prediction would inaugurate the physics of the twenty-first century.
Noyes, H.P.
Assessing Hypothetical Gravity Control Propulsion
Gauging the benefits of hypothetical gravity control propulsion is difficult, but addressable. The major challenge is that such breakthroughs are still only notional concepts rather than being specific methods from which performance can be rigorously quantified. A recent assessment by Tajmar and Bertolami used the rocket equation to correct naive misconceptions, but a more fundamental analysis requires the use of energy as the basis for comparison. The energy of a rocket is compared to an idealized space drive for the following cases: Earth-to-orbit, interstellar transit, and levitation. The space drive uses 3.6 times less energy for Earth to orbit. For deep space travel, space drive energy scales as the square of delta-v, while rocket energy scales exponentially. This has the effect of rendering a space drive 150-orders-of-magnitude better than a 17,000-sec Specific Impulse rocket for sending a modest 5000 kg probe to traverse 5 light-years in 50 years. Indefinite levitation, which is impossible for a rocket, could conceivably require 62 MJ/kg for a space drive. Assumption sensitivities and further analysis options are listed to guide further inquires.
Marc G. Millis
Deeply virtual Compton scattering from gauge/gravity duality
We use gauge/gravity duality to study deeply virtual Compton scattering (DVCS) in the limit of high center of mass energy at fixed momentum transfer, corresponding to the limit of low Bjorken x, where the process is dominated by the exchange of the pomeron. At strong coupling, the pomeron is described as the graviton Regge trajectory in AdS space, with a hard wall to mimic confinement effects. This model agrees with HERA data in a large kinematical range. The behavior of the DVCS cross section for very high energies, inside saturation, can be explained by a simple AdS black disk model. In a restricted kinematical window, this model agrees with HERA data as well.
Costa, Miguel S.; Djuric, Marko [University of Porto (Portugal)
Mass spectrum and thermodynamics of quasiconformal gauge theories from gauge/gravity duality
We use gauge/gravity duality to study simultaneously the mass spectrum and the thermodynamics of a generic quasiconformal gauge theory, specified by its beta function. The beta function of a quasiconformal theory almost vanishes, and the coupling is almost constant between two widely separated energy scales. Depending on whether the gravity dual has a black hole or not, the mass spectrum is either a spectrum of quasinormal oscillations or a normal T=0 mass spectrum. The mass spectrum is quantitatively correlated with the thermal properties of the system. As the theory approaches conformality, the masses have to vanish. We show that in this limit, the masses calculated via gauge/gravity duality satisfy expected scaling properties.
Alanen, J.; Kajantie, K. [Department of Physics, P.O. Box 64, FI-00014 University of Helsinki (Finland); Helsinki Institute of Physics, P.O. Box 64, FI-00014 University of Helsinki (Finland); Alho, T.; Tuominen, K. [Helsinki Institute of Physics, P.O. Box 64, FI-00014 University of Helsinki (Finland); Department of Physics, University of Jyvaeskylae (Finland)
Black Holes or Frozen Stars? A Viable Theory of Gravity without Black Holes
Do observations of black hole candidates rule out alternative theories of gravity without horizon formation? This depends on the existence, viability and reasonableness of alternative theories of gravity without black holes. Here a theory of gravity without black hole horizon formation is presented. The gravitational collapse stops shortly before horizon formation and leaves a stable frozen star. In the limit $\\Xi, \\Upsilon\\to 0$ the Einstein equations of GR are recovered, and the frozen stars become observationally indistinguishable from GR black holes. The theory therefore provides a counterexample to recent claims that observational evidence from black hole candidates "all but requires the existence of a horizon". The theory presented here shares its equations with RTG. Nonetheless, as is shown, there remain important conceptual and physical differences. In particular, some serious problems of RTG are not present in the theory proposed here. So it can be argued that the theory is a physically viable and conceptually sound alternative to GR.
I. Schmelzer
2012 NERSC User Survey
Results 2012 User Survey Text 2012 NERSC User Survey Text The 2012 NERSC User Survey is closed. The following is the text of the survey. Section 1: Overall Satisfaction with...
The genus of the isodensity contours is a robust measure of the topology of a large-scale structure, and it is relatively insensitive to nonlinear gravitational evolution, galaxy bias, and redshift-space distortion. We show that the growth of density fluctuations is scale dependent even in the linear regime in some modified gravity theories, which opens a new possibility of testing the theories observationally. We propose to use the genus of the isodensity contours, an intrinsic measure of the topology of the large-scale structure, as a statistic to be used in such tests. In Einstein's general theory of relativity, density fluctuations grow at the same rate on all scales in the linear regime, and the genus per comoving volume is almost conserved as structures grow homologously, so we expect that the genus-smoothing-scale relation is basically time independent. However, in some modified gravity models where structures grow with different rates on different scales, the genus-smoothing-scale relation should change over time. This can be used to test the gravity models with large-scale structure observations. We study the cases of the f(R) theory, DGP braneworld theory as well as the parameterized post-Friedmann models. We also forecast how the modified gravity models can be constrained with optical/IR or redshifted 21 cm radio surveys in the near future.
Wang Xin; Chen Xuelei [Key Laboratory of Optical Astronomy, National Astronomical ObservatoriesChinese Academy of Sciences, Beijing 100012 (China); Park, Changbom [Korea Institute for Advanced Study, Dongdaemun-gu, Seoul 130-722 (Korea, Republic of)
Gravity model studies of Newberry Volcano, Oregon
Newberry, Volcano, a large Quaternary volcano located about 60 km east of the axis of the High Cascades volcanoes in central Oregon, has a coincident positive residual gravity anomaly of about 12 mGals. Model calculations of the gravity anomaly field suggest that the volcano is underlain by an intrusive complex of mafic composition of about 20-km diameter and 2-km thickness, at depths above 4 km below sea level. However, uplifted basement in a northwest trending ridge may form part of the underlying excess mass, thus reducing the volume of the subvolcanic intrusive. A ring dike of mafic composition is inferred to intrude to near-surface levels along the caldera ring fractures, and low-density fill of the caldera floor probably has a thickness of 0.7--0.9 km. The gravity anomaly attributable to the volcano is reduced to the east across a north-northwest trending gravity anomaly gradient through Newberry caldera and suggests that normal, perhaps extensional, faulting has occurred subsequent to caldera formation and may have controlled the location of some late-stage basaltic and rhyolitic eruptions. Significant amounts of felsic intrusive material may exist above the mafic intrusive zone but cannot be resolved by the gravity data.
Gettings, M.E.; Griscom, A.
A Survey on Cloud Provider Security
A Survey on Cloud Provider Security Measures Alex Pucher, Stratos Dimopoulos Abstract Cloud take advantage of this model already, but security and privacy concerns limit the further adoption agencies and start offering security certifications and separate tightly controlled "government" cloud
Gravitational Shock Waves and Their Scattering in Brane-Induced Gravity
In this paper, following hep-th/0501028, we present a detailed derivation and discussion of the exact gravitational field solutions for a relativistic particle localized on a tensional brane in brane-induced gravity. Our derivation yields the metrics for both the normal branch and the self-inflating branch DGP braneworlds. They generalize the 4D gravitational shock waves in de Sitter space, and so we compare them to the corresponding 4D General Relativity solution and to the case when gravity resides only in the 5D bulk, and there are no brane-localized graviton kinetic terms. We write down the solutions in terms of two-variable hypergeometric functions and find that at short distances the shock wave profiles look exactly the same as in 4D Minkowski space, thus recovering the limit one expects if gravity is to be mediated by a metastable, but long-lived, bulk resonance. The corrections far from the source differ from the long distance corrections in 4D de Sitter space, coming in with odd powers of the distance. We discuss in detail the limiting case on the self-inflating branch when gravity is modified exactly at de Sitter radius, and energy can be lost into the bulk by resonance-like processes. Finally, we consider Planckian scattering on the brane, and find that for a sufficiently small impact parameter it is approximated very closely by the usual 4D description.
Nemanja Kaloper
Process Limits on Euclid
Process Limits Process Limits Limit Hard Soft core file size (blocks) 0 unlimited data seg size (kbytes) unlimited unlimited scheduling priority 0 0 file size (blocks) unlimited...
Problems with Mannheim's conformal gravity program
We show that Mannheim's conformal gravity program, whose potential has a term proportional to $1/r$ and another term proportional to $r$, does not reduce to Newtonian gravity at short distances, unless one assumes undesirable singularities of the mass density of the proton. Therefore, despite the claim that it successfully explains galaxy rotation curves, unless one assumes the singularities, it seems to be falsified by numerous Cavendish-type experiments performed at laboratories on Earth whose work have not found any deviations from Newton's theory. Moreover, it can be shown that as long as the total mass of the proton is positive, Mannheim's conformal gravity program leads to negative linear potential, which is problematic from the point of view of fitting galaxy rotation curves, which necessarily requires positive linear potential.
Youngsub Yoon
Energy Distribution in f(R) Gravity
The well-known energy problem is discussed in f(R) theory of gravity. We use the generalized Landau-Lifshitz energy-momentum complex in the framework of metric f(R) gravity to evaluate the energy density of plane symmetric solutions for some general f(R) models. In particular, this quantity is found for some popular choices of f(R) models. The constant scalar curvature condition and the stability condition for these models are also discussed. Further, we investigate the energy distribution of cosmic string spacetime.
Sharif, M
M. Sharif; M. Farasat Shamir
Gravity waves from vortex dipoles and jets
The dissertation first investigates gravity wave generation and propagation from jets within idealized vortex dipoles using a nonhydrostatic mesoscale model. Several initially balanced and localized jets induced by vortex dipoles are examined here. Within these dipoles, inertia-gravity waves with intrinsic frequencies 1-2 times the Coriolis parameter are simulated in the jet exit region. The ray tracing analysis reveals strong variation of wave characteristics along ray paths. The dependence of wave amplitude on the Rossby number is examined through experiments in which the two vortices are initially separated by a large distance but subsequently approach each other and form a vortex dipole with an associated amplifying localized jet. The amplitude of stationary gravity waves in the simulations with a 90-km grid spacing increases nearly linearly with the square of the Rossby number but significantly more rapidly when smaller grid spacing is used. To further address the source mechanism of the gravity waves within the vortex dipole, a linear numerical framework is developed based on the framework proposed by Plougonven and Zhang (2007). Using the nonlinearly balanced fields as the basic state and driven by three types of large scale forcing, the vorticity, divergence and thermodynamic forcing, this linear model is utilized to obtain linear wave responses. The wave packets in the linear responses compare reasonably well with the MM5 simulated gravity waves. It is suggested that the vorticity forcing is the leading contribution to both gravity waves in the jet exit region and the ascent/descent feature in the jet core. This linear model is also adopted to study inertia-gravity waves in the vicinity of a baroclinic jet during the life cycle of an idealized baroclinic wave. It is found that the thermodynamic forcing and the vorticity forcing are equally important to the gravity waves in the low stratosphere, but the divergence forcing is again playing a lesser role. Two groups of wave packets are present in the linear responses; their sources appear to locate either near the surface front or near the middle/upper tropospheric jet.
Wang, Shuguang
Proper Time Flow Equation for Gravity
We analyze a proper time renormalization group equation for Quantum Einstein Gravity in the Einstein-Hilbert truncation and compare its predictions to those of the conceptually different exact renormalization group equation of the effective average action. We employ a smooth infrared regulator of a special type which is known to give rise to extremely precise critical exponents in scalar theories. We find perfect consistency between the proper time and the average action renormalization group equations. In particular the proper time equation, too, predicts the existence of a non-Gaussian fixed point as it is necessary for the conjectured nonperturbative renormalizability of Quantum Einstein Gravity.
Linear Stratospheric Gravity Waves above Convective Thermal Forcing
The spectra of linear gravity waves generated by a time-varying tropospheric thermal forcing representing organized convection are compared to the spectra of stratospheric gravity waves generated by organized convection in a fully nonlinear two-...
Rajul E. Pandya; M. Joan Alexander
Coupling between Gravity Waves and Tropical Convection at Mesoscales
An idealized cloud-system-resolving model simulation is used to examine the coupling between a tropical cloud population and the mesoscale gravity waves that it generates. Spectral analyses of the cloud and gravity wave fields identify a clear ...
Todd P. Lane; Fuqing Zhang
New Gravity Wave Treatments for GISS Climate Models
Previous versions of GISS climate models have either used formulations of Rayleigh drag to represent unresolved gravity wave interactions with the model-resolved flow or have included a rather complicated treatment of unresolved gravity waves that,...
Marvin A. Geller; Tiehan Zhou; Reto Ruedy; Igor Aleinov; Larissa Nazarenko; Nikolai L. Tausnev; Shan Sun; Maxwell Kelley; Ye Cheng
Influence of Gravity Waves in the Tropical Upwelling: WACCM Simulations
The annual cycle of tropical upwelling and contributions by planetary and gravity waves are investigated from climatological simulations using the Whole Atmosphere Community Climate Model (WACCM) including three gravity wave drag (GWD) ...
Hye-Yeong Chun; Young-Ha Kim; Hyun-Joo Choi; Jung-Yoon Kim
Mobility Characterization of Planetary Rover in Reduced Gravity Environment
This paper describes effects of gravity on mobility performance of wheeled rovers for future lunar/planetary exploration missions. A series of model tests of a wheel?terrain system were performed on an aircraft during variable gravity maneuvers
Taizo Kobayashi; Hidetoshi Ochiai; Junya Yamakawa; Shigeru Aoki; Kai Matsui; Akira Miyahara
Correlation Between Precision Gravity and Subsidence Measurements at Cerro Prieto
PRECISION GRAVITY AND SUBSIDENCE MEASUREMENTS AT CERROPRECISION GRAVITY AND SUBSIDENCE MEASUREMENTS AT CERROn d i c a t e s t h a t subsidence took place. Uost of t h e
Zelwer, R.
Numerical Study of Gravity Currents in a Channel
A three-dimensional primitive-equation model was used to study gravity currents produced by instantaneous releases of a buoyant fluid in a rectangular channel. Without rotation, the gravity current passes through two distinct phases: an initial ...
Dong-Ping Wang
An Ultrasimple Spectral Parameterization for Nonorographic Gravity Waves
This paper describes a new computationally efficient, ultrasimple nonorographic spectral gravity wave parameterization model. Its predictions compare favorably, though not perfectly, with a model of gravity wave propagation and breaking that ...
C. D. Warner; M. E. McIntyre
Quantum gravity as a group field theory: a sketch
We give a very brief introduction to the group field theory approach to quantum gravity, a generalisation of matrix models for 2-dimensional quantum gravity to higher dimension, that has emerged recently from research in spin foam models.
Daniele Oriti
Linear Spectral Numerical Model for Internal Gravity Wave Propagation
A three-dimensional linear spectral numerical model is proposed to simulate the propagation of internal gravity wave fluctuations in a stably stratified atmosphere. The model is developed to get first-order estimations of gravity wave ...
J. Marty; F. Dalaudier
An Unusually Strong Gravity Wave over Western Washington
A mesoscale wave disturbance, observed over western Washington State, is studied through local observations and recognized by comparisons with theory as a large-amplitude gravity wave. It is shown that this gravity wave propagated over 200 km in ...
Bruce H. Bauck
Gravity monitoring of CO{sub 2} movement during sequestration: Model studies
Sequestration/enhanced oil recovery (EOR) petroleum reservoirs have relatively thin injection intervals with multiple fluid components (oil, hydrocarbon gas, brine, and carbon dioxide, or CO{sub 2}), whereas brine formations usually have much thicker injection intervals and only two components (brine and CO{sub 2}). Coal formations undergoing methane extraction tend to be thin (3-10 m) but shallow compared to either EOR or brine formations. Injecting CO{sub 2} into an oil reservoir decreases the bulk density in the reservoir. The spatial pattern of the change in the vertical component of gravity (G{sub z}) is correlated directly with the net change in reservoir density. Furthermore, time-lapse changes in the borehole G{sub z} clearly identify the vertical section of the reservoir where fluid saturations are changing. The CO{sub 2}-brine front, on the order of 1 km within a 20-m-thick brine formation at 1900-m depth with 30% CO{sub 2} and 70% brine saturations, respectively, produced a -10-{mu} Gal surface gravity anomaly. Such an anomaly would be detectable in the field. The amount of CO{sub 2} in a coal-bed methane scenario did not produce a large enough surface gravity response; however, we would expect that for an industrial-size injection, the surface gravity response would be measurable. Gravity inversions in all three scenarios illustrate that the general position of density changes caused by CO{sub 2} can be recovered but not the absolute value of the change. Analysis of the spatial resolution and detectability limits shows that gravity measurements could, under certain circumstances, be used as a lower-cost alternative to seismic measurements.
Gasperikova, E.; Hoversten, G.M. [Lawrence Berkeley National Laboratory, Berkeley, CA (United States)
The behavior of $f(R)$ gravity in the solar system, galaxies and clusters
For cosmologically interesting $f(R)$ gravity models, we derive the complete set of the linearized field equations in the Newtonian gauge, under environments of the solar system, galaxies and clusters respectively. Based on these equations, we confirmed previous $\\gamma=1/2$ solution in the solar system. However, $f(R)$ gravity models can be strongly environment-dependent and the high density (comparing to the cosmological mean) solar system environment can excite a viable $\\gamma=1$ solution for some $f(R)$ gravity models. Although for $f(R)\\propto -1/R$, it is not the case; for $f(R)\\propto -\\exp(-R/\\lambda_2H_0^2)$, such $\\gamma=1$ solution does exist. This solution is virtually indistinguishable from that in general relativity (GR) and the value of the associated curvature approaches the GR limit, which is much higher than value in the $\\gamma=1/2$ solution. We show that for some forms of $f(R)$ gravity, this solution is physically stable in the solar system and can smoothly connect to the surface of the Sun. The derived field equations can be applied directly to gravitational lensing of galaxies and clusters. We find that, despite significant difference in the environments of galaxies and clusters comparing to that of the solar system, gravitational lensing of galaxies and clusters can be virtually identical to that in GR, for some forms of $f(R)$ gravity. Fortunately, galaxy rotation curve and intra-cluster gas pressure profile may contain valuable information to distinguish these $f(R)$ gravity models from GR.
Pengjie Zhang
U.S. Percent Total Imported by API Gravity of Crude ...
Referring Pages: Percentages of Total Imported Crude Oil by API Gravity; Percentages of Total Imported Crude Oil by API Gravity
Rapid gravity and gravity gradiometry terrain correction via adaptive quadtree mesh discretization Kristofer Davis, M. Andy Kass, and Yaoguo Li, Center for Gravity, Electrical and Magnetic Studies, Colorado School
Rapid gravity and gravity gradiometry terrain correction via adaptive quadtree mesh discretization Kristofer Davis, M. Andy Kass, and Yaoguo Li, Center for Gravity, Electrical and Magnetic Studies, Colorado School of Mines SUMMARY We present a method for modeling the terrain response in gravity and gravity
Hypothetical Gravity Control and Implications for Spacecraft Propulsion
A scientific analysis of the conditions under which gravity could be controlled and the implications that an hypothetical manipulation of gravity would have for known schemes of space propulsion have been the scope of a recent study carried out for the European Space Agency. The underlying fundamental physical principles of known theories of gravity were analysed and shown that even if gravity could be modified it would bring somewhat modest gains in terms of launching of spacecraft and no breakthrough for space propulsion.
O. Bertolami; M. Tajmar
Exact solutions with noncommutative symmetries in Einstein and gauge gravity
We present new classes of exact solutions with noncommutative symmetries constructed in vacuum Einstein gravity (in general
Sergiu I. Vacaru
Materials Science in Reduced Gravity - Programmaster.org
Jul 31, 2012 ... About this Symposium. Meeting, 2013 TMS Annual Meeting & Exhibition. Symposium, Materials Science in Reduced Gravity. Sponsorship�...
Gravity and Yang?Mills Fields: Geometrical Approaches
A new geometrical framework for a tetrad?affine formulation of gravity coupled with Yang?Mills fields is proposed.
Roberto Cianci; Stefano Vignolo
Gravity Waves in Shear and Implications for Organized Convection
Gravity Waves in Shear and Implications for Organized Convection Samuel N. Stechmann Department, Los Angeles, CA 900951555. E-mail: email@example.com #12;ABSTRACT It is known that gravity, the gravity waves can create a more favorable environment on one side of preexisting convection than the other
Stechmann, Samuel N.
Tomo-gravity How to ComputeHow to Compute
Tomo-gravity How to ComputeHow to Compute Accurate Traffic Matrices forAccurate Traffic MatricesStanford Shannon LabShannon Lab #12;Tomo-gravity Want to know demands from source to destination ProblemProblem Have link traffic measurements (from SNMP) A B C #12;Tomo-gravity Example App: reliability analysis
Roughan, Matthew
Gravity Load Collapse of Building Frames during Earthquakes
Gravity Load Collapse of Building Frames during Earthquakes J. P. Moehle, K. J. Elwood, H. Sezen to frames designed primarily for gravity loads. Columns generally were not designed to have strengths capacity of the column. As the axial capacity diminishes, the gravity loads carried by the column must
Sezen, Halil
Gravity currents in two-layer stratified media
Gravity currents in two-layer stratified media Morris R. Flynn & Alan W.Tan Dept. of Mechanical Engineering, U.Alberta Funding: NSERC #12;· Gravity currents appear over a broad range of time/length scales. (1999), Flynn & Linden (2006),White & Helfrich (2008), Ungarish (2009) Introduction current gravity
Gravity Surface Wave Bifurcation in a Highly Turbulent Swirling Flow
Gravity Surface Wave Bifurcation in a Highly Turbulent Swirling Flow Michael Baumer University Gravity Wave 2 3 Measurements 3 4 Mechanical Hardware: Problems and Solutions 5 5 Results 7 6 Conclusions investigated a free-surface gravity wave bifurcation in the large-separation regime, that is, where
Witten, Thomas A.
Gravity waves excited by jets: Propagation versus generation R. Plougonven
Gravity waves excited by jets: Propagation versus generation R. Plougonven School of Mathematics September 2005. [1] Atmospheric jets are known to be an important source of inertia-gravity waves, yet mechanisms for the gravity waves, with the underlying assumption that the characteristics of the waves were
Plougonven, Riwal
Mass gap for gravity localized on thick branes
We present a scalar thick brane configuration arising in a theory of 5D gravity coupled to a self�interacting scalar field. We start from a classical solution of the field equations and study the physics of linear fluctuations around this background which obey a Schr�dinger�like equation. We further focus our attention on a special case in which it is possible to solve this equation analytically for any massive mode. This fact allows us to make a closed analysis of the massive spectrum of Kaluza�Klein (KK) excitations and to compute the corrections to Newton�s law in the thin brane limit. There exist two bound states: the massless 4D graviton
N. Barbosa�Cendejas; A. Herrera�Aguilar; U. Nucamendi; I. Quiros; M. A. Reyes Santos; C. Schubert
Sound damping constant for generalized theories of gravity
The near-horizon metric for a black brane in anti-de Sitter space and the metric near the AdS boundary both exhibit hydrodynamic behavior. We demonstrate the equivalence of this pair of hydrodynamic systems for the sound mode of a conformal theory. This is first established for Einstein's gravity, but we then show how the sound damping constant will be modified from its Einstein form for a generalized theory. The modified damping constant is expressible as the ratio of a pair of gravitational couplings that are indicative of the sound-channel class of gravitons. This ratio of couplings differs from both that of the shear diffusion coefficient and the shear viscosity to entropy ratio. Our analysis is mostly limited to conformal theories, but suggestions are made as to how this restriction might eventually be lifted.
Brustein, Ram [Department of Physics, Ben-Gurion University, Beer-Sheva, 84105 (Israel); Medved, A. J. M. [Physics Department, University of Seoul, Seoul 130-743 (Korea, Republic of)
Modulated Ground State of Gravity Theories with Stabilized Conformal Factor
We discuss the stabilization of the conformal factor by higher derivative terms in a conformally reduced $R+R^2$ Euclidean gravity theory. The flat spacetime is unstable towards the condensation of modes with nonzero momentum, and they "condense" in a modulated phase above a critical value of the coupling $\\beta$ of the $R^2$ term. By employing a combination of variational, numerical and lattice methods we show that in the semiclassical limit the corresponding functional integral is dominated by a single nonlinear plane wave of frequency $\\approx 1/\\sqrt{\\beta} \\lp$. We argue that the ground state of the theory is characterized by a spontaneous breaking of translational invariance at Planckian scales.
Bonanno, Alfio
Universality and Symmetry Breaking in Conformally Reduced Quantum Gravity
The scaling properties of quantum gravity are discussed by employing a class of proper-time regulators in the functional flow equation for the conformal factor within the formalism of the background field method. Renormalization group trajectories obtained by projecting the flow on a flat topology are more stable than those obtained from a projection on a spherical topology. In the latter case the ultraviolet flow can be characterized by a Hopf bifurcation with an ultraviolet attractive limiting cycle. Although the possibility of determining the infrared flow for an extended theory space can be severely hampered due to the conformal factor instability, we present a robust numerical approach to study the flow structure around the non-gaussian fixed point as an inverse-problem strategy. In particular it is shown the possibility of having a spontaneous breaking of the diffeomorphism invariance can be realized with non-local functionals of the volume operator.
Effects of Nonlinearity on Convectively Forced Internal Gravity Waves: Application to a Gravity Wave Drag Parameterization
In the present study, the authors propose a way to include a nonlinear forcing effect on the momentum flux spectrum of convectively forced internal gravity waves using a nondimensional numerical model (NDM) in a two-dimensional framework. In NDM, ...
Hye-Yeong Chun; Hyun-Joo Choi; In-Sun Song
Convective Generation of Gravity Waves in Venus's Atmosphere: Gravity Wave Spectrum and Momentum Transport
The emission of internal gravity waves from a layer of dry convection embedded within a stable atmosphere with static stability and zonal winds varying in height is calculated. This theory is applied to Venus to investigate whether these waves ...
Stephen S. Leroy; Andrew P. Ingersoll
The Mars Gravity Biosatellite as an innovative partial gravity research platform
The Mars Gravity Biosatellite is an unprecedented independent spaceflight platform for gravitational biology research. With a projected first launch after 2010, the low Earth orbit satellite will support a cohort of fifteen ...
Fulford-Jones, Thaddeus R. F
Improvement of Orographic Gravity Wave Parameterization Using a Mesoscale Gravity Wave Model
Parameterization of gravity waves due to subgrid-scale orography is now included in most existing large-scale models of the atmosphere. Parameterization schemes, however, have so far been evaluated mainly in view of the overall performance of the ...
Young-Joon Kim; Akio Arakawa
Atmospheric Gravity Waves and Aircraft Turbulence Encounters
We describe aircraft turbulence-atmospheric gravity wave events which occurred during a 2-day period over the Continental Divide. The waves are observed by two microbarograph networks an each side of the divide and last for several hours at a ...
A. J. Bedard Jr.; F. Canavero; F. Einaudi
We investigate the effect of modified gravity on the specific angular momentum of galactic halos by analyzing the halo catalogs at z = 0 from high-resolution N-body simulations for a f(R) gravity model that meets the solar-system constraint. It is shown that the galactic halos in the f(R) gravity model tend to acquire significantly higher specific angular momentum than those in the standard {Lambda}CDM model. The largest difference in the specific angular momentum distribution between these two models occurs for the case of isolated galactic halos with mass less than 10{sup 11} h {sup -1} M {sub Sun }, which are likely least shielded by the chameleon screening mechanism. As the specific angular momentum of galactic halos is rather insensitive to other cosmological parameters, it can in principle be an independent discriminator of modified gravity. We speculate a possibility of using the relative abundance of low surface brightness galaxies (LSBGs) as a test of general relativity given that the formation of the LSBGs occurs in fast spinning dark halos.
Lee, Jounghun [Astronomy Program, Department of Physics and Astronomy, FPRD, Seoul National University, Seoul 151-747 (Korea, Republic of)] [Astronomy Program, Department of Physics and Astronomy, FPRD, Seoul National University, Seoul 151-747 (Korea, Republic of); Zhao, Gong-Bo [National Astronomy Observatories, Chinese Academy of Science, Beijing 100012 (China)] [National Astronomy Observatories, Chinese Academy of Science, Beijing 100012 (China); Li, Baojiu [Institute of Computational Cosmology, Department of Physics, Durham University, Durham DH1 3LE (United Kingdom)] [Institute of Computational Cosmology, Department of Physics, Durham University, Durham DH1 3LE (United Kingdom); Koyama, Kazuya, E-mail: email@example.com [Institute of Cosmology and Gravitation, University of Portsmouth, Portsmouth, PO1 3FX (United Kingdom)] [Institute of Cosmology and Gravitation, University of Portsmouth, Portsmouth, PO1 3FX (United Kingdom)
Gravity Currents in a Deep Anelastic Atmosphere
This study presents analytic results for steady gravity currents in a channel using the deep anelastic equations. Results are cast in terms of a nondimensional parameter H/H0 that relates the channel depth H to a scale depth H0 (the depth at ...
George H. Bryan; Richard Rotunno
Gravity Waves, Dynamical Resistance, and Forcing Efficiency
The effect of the dynamical response associated with high-frequency gravity waves on the total energy generated by imposed heating is examined in a 2D linear compressible model. The work performed by waves against a sustained forcing is defined ...
Jeffrey M. Chagnon
Energy definition for quadratic curvature gravities
A conserved current for generic quadratic curvature gravitational models is defined, and it is shown that, at the linearized level, it corresponds to the Deser-Tekin charges. An explicit expression for the charge for new massive gravity in three dimensions is given. Some implications of the linearized equations are discussed.
Ahmet Baykal
Ultrasonic hydrometer. [Specific gravity of electrolyte
The disclosed ultrasonic hydrometer determines the specific gravity (density) of the electrolyte of a wet battery, such as a lead-acid battery. The hydrometer utilizes a transducer that when excited emits an ultrasonic impulse that traverses through the electrolyte back and forth between spaced sonic surfaces. The transducer detects the returning impulse, and means measures the time t between the initial and returning impulses. Considering the distance d between the spaced sonic surfaces and the measured time t, the sonic velocity V is calculated with the equation V = 2d/t. The hydrometer also utilizes a thermocouple to measure the electrolyte temperature. A hydrometer database correlates three variable parameters including sonic velocity in and temperature and specific gravity of the electrolyte, for temperature values between 0 and 40/sup 0/C and for specific gravity values between 1.05 and 1.30. Upon knowing two parameters (the calculated sonic velocity and the measured temperature), the third parameter (specific gravity) can be uniquely found in the database. The hydrometer utilizes a microprocessor for data storage and manipulation.
Swoboda, C.A.
Multiple Gravity-Wave Breaking Levels
It is noted that gravity waves for which |u�?c| (u�=mean flow speed, c=wave phase speed) has a sharp minimum in the upper troposphere or lower stratosphere will have decaying amplitudes above this level despite exponentially decreasing mean ...
Richard S. Lindzen
Cosmological singularities and modified theories of gravity
We consider perturbative modifications of the Friedmann equations in terms of energy density corresponding to modified theories of gravity proposed as an alternative route to comply with the observed accelerated expansion of the universe. Assuming that the present matter content of the universe is a pressureless fluid
Leonardo Fern�ndez?Jambrina; Ruth Lazkoz
Superadiabatic Excess and Gravity Wave Saturation
Attention is called to a recent calculation of the superadiabatic excess�the ratio of wave amplitude at saturation to wave amplitude at convective instability threshold�caused by a saturated gravity wave. (This excess is also referred to as the ...
J. Weinstock
Heat Transfer in Superfluids: Effect of Gravity
We discuss the influence of an external field on energy transport in superfluid. He-II is not isothermal in presence of Earth gravity; instead, it supports finite temperature gradient given by a Fourier-like equation. We calculate asymptotic behavior of the effective heat resistance in the vicinity of the $\\lambda$-transition.
L. A. Melnikovsky
Charged Black Holes in New Massive Gravity
We construct charged black hole solutions to three-dimensional New Massive Gravity (NMG), by adding electromagnetic Maxwell and Chern-Simons actions. We find charged black holes in the form of warped AdS_3 and "log" solutions in specific critical point. The entropy, mass and angular momentum of these black holes are computed.
Ghodsi, Ahmad
Free Gravity Waves and Balanced Dynamics
It is shown how a renormalization technique, which is a variant of classical Krylov�Bogolyubov�Mitropol'skii averaging, can be used to obtain slow evolution equations for the vortical and inertia�gravity wave components of the dynamics in a ...
D. Wirosoetisno; T. G. Shepherd; R. M. Temam
On white dwarfs and neutron stars in Palatini f(R) gravity
In Palatini $f(R)$ gravity, the parameters of the Schwarzschild - de Sitter solution as well as the whole interior solutions of compact objects are expected to change when compared to general relativity. We solve the Palatini field equations numerically in the case of the models $f(R) = R + \\alpha R^2$ and $f(R) = R - \\mu^4/R$, and using the equation of state of Fermi gas. We show how the density profiles and the prediction for the maximum masses of white dwarfs (the Chandrasekhar limit) and neutron stars (the Tolman-Oppenheimer-Volkoff limit) are altered, and thereby conclude that observations on compact stars may be used to exclude alternative gravity models.
Vappu Reijonen
Nonlinearities in modified gravity cosmology: Signatures of modified gravity in the nonlinear matter power spectrum
A large fraction of cosmological information on dark energy and gravity is encoded in the nonlinear regime. Precision cosmology thus requires precision modeling of nonlinearities in general dark energy and modified gravity models. We modify the Gadget-2 code and run a series of N-body simulations on modified gravity cosmology to study the nonlinearities. The modified gravity model that we investigate in the present paper is characterized by a single parameter {zeta}, which determines the enhancement of particle acceleration with respect to general relativity (GR), given the identical mass distribution ({zeta}=1 in GR). The first nonlinear statistics we investigate is the nonlinear matter power spectrum at k < or approx. 3h/Mpc, which is the relevant range for robust weak lensing power spectrum modeling at l < or approx. 2000. In this study, we focus on the relative difference in the nonlinear power spectra at corresponding redshifts where different gravity models have the same linear power spectra. This particular statistics highlights the imprint of modified gravity in the nonlinear regime and the importance of including the nonlinear regime in testing GR. By design, it is less susceptible to the sample variance and numerical artifacts. We adopt a mass assignment method based on wavelet to improve the power spectrum measurement. We run a series of tests to determine the suitable simulation specifications (particle number, box size, and initial redshift). We find that, the nonlinear power spectra can differ by {approx}30% for 10% deviation from GR (|{zeta}-1|=0.1) where the rms density fluctuations reach 10. This large difference, on one hand, shows the richness of information on gravity in the corresponding scales, and on the other hand, invalidates simple extrapolations of some existing fitting formulae to modified gravity cosmology.
Cui Weiguang; Zhang Pengjie; Yang Xiaohu [Key Laboratory for Research in Galaxies and Cosmology, Shanghai Astronomical Observatory, Partner Group of MPA, Nandan Road 80, Shanghai, 200030 (China)
Inelastic collapse in one-dimensional driven systems under gravity
We study the inelastic collapse in the one-dimensional $N$-particle systems in the situation where the system is driven from below under the gravity. We investigate the hard-sphere limit of the inelastic soft-sphere systems by numerical simulations to find how the collision rate per particle $n_{coll}$ increases as a function of the elastic constant of the sphere $k$ when the restitution coefficient $e$ is kept constant. For the systems with large enough $N \\agt 20$, we find three regimes in $e$ depending on the behavior of $n_{coll}$ in the hard-sphere limit: (i) uncollapsing regime for $1 \\ge e > e_{c1}$, where $n_{coll}$ converges to a finite value, (ii) logarithmically collapsing regime for $e_{c1} > e > e_{c2}$, where $n_{coll}$ diverges as $n_{coll} \\sim \\log k$, and (iii) power-law collapsing regime for $e_{c2} > e > 0$, where $n_{coll}$ diverges as $n_{coll} \\sim k^\\alpha$ with an exponent $\\alpha$ that depends on $N$. The power-law collapsing regime shrinks as $N$ decreases and seems not to exist for the system with N=3 while, for large $N$, the size of the uncollapsing and the logarithmically collapsing regime decreases as $e_{c1} \\simeq 1-2.6/N$ and $e_{c2} \\simeq 1-3.0/N$. We demonstrate that this difference between large and small systems exists already in the inelastic collapse without the external drive and the gravity.
Jun'ichi Wakou; Hiroyuki Kitagishi; Takahiro Sakaue; Hiizu Nakanishi
Static spherically symmetric perfect fluid solutions in $f(R)$ theories of gravity
Static spherically symmetric perfect fluid solutions are studied in metric $f(R)$ theories of gravity. We show that pressure and density do not uniquely determine $f(R)$ ie. given a matter distribution and an equation state, one cannot determine the functional form of $f(R)$. However, we also show that matching the outside Schwarzschild-de Sitter-metric to the metric inside the mass distribution leads to additional constraints that severely limit the allowed fluid configurations.
T. Multamaki; I. Vilja
1998 NERSC User Survey Results
8 User Survey Results 1998 User Survey Results Respondent Summary NERSC has completed its first user survey since its move to Lawrence Berkeley National Laboratory. The survey is...
Holographic Entanglement Entropy for 4D Conformal Gravity
Using the proposal for holographic entanglement entropy in higher derivative gravities, we compute holographic entanglement entropy for the conformal gravity in four dimensions which turns out to be finite. However, if one subtracts the contribution of the four dimensional Gauss-Bonnet term, the corresponding entanglement entropy has a divergent term and indeed restricted to an Einstein solution of the conformal gravity, the resultant entanglement entropy is exactly the same as that in the Einstein gravity. We will also make a comment on the first law of the entanglement thermodynamics for the conformal gravity in four dimensions.
Mohsen Alishahiha; Amin Faraji Astaneh; M. Reza Mohammadi Mozaffar
On the z=4 Horava-Lifshitz Gravity
We consider z=4 Horava-Lifshitz gravity in both 3+1 and 4+1 dimensions. We find black hole solutions in the IR region for a kind of z=4 Horava-Lifshitz gravity which is inherited from the new massive gravity in three dimensions and an analog of the new massive gravity in four dimensions through the quantum inheritance principle. We analyze thermodynamic properties for the black hole solutions for z=4 Horava-Lifshitz gravity. We also write out the Friedmann equation in 3+1 dimensions for cosmological solutions.
Rong-Gen Cai; Yan Liu; Ya-Wen Sun
Granular convection and the Brazil nut effect in reduced gravity
We present laboratory experiments of a vertically vibrated granular medium consisting of 1 mm diameter glass beads with embedded 8 mm diameter intruder glass beads. The experiments were performed in the laboratory as well as in a parabolic flight under reduced-gravity conditions (on Martian and Lunar gravity levels). We measured the mean rise velocity of the large glass beads and present its dependence on the fill height of the sample containers, the excitation acceleration, and the ambient gravity level. We find that the rise velocity scales in the same manner for all three gravity regimes and roughly linearly with gravity.
Carsten G�ttler; Ingo von Borstel; Rainer Schr�pler; J�rgen Blum
Direct-Current Resistivity Survey At Lightning Dock Area (Warpinski, Et
Et Et Al., 2002) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Direct-Current Resistivity Survey At Lightning Dock Area (Warpinski, Et Al., 2002) Exploration Activity Details Location Lightning Dock Area Exploration Technique Direct-Current Resistivity Survey Activity Date Usefulness not indicated DOE-funding Unknown Notes As a foundation for successful siting and drilling a deep test well, additional geophysical work has been completed including gravity, resistivity, and airborne magnetic surveys. Several new seismic profiles are planned to provide more focused siting and drilling plans. These new geophysical surveys are being integrated into the combined thermal, hydrologic, and subsurface stratigraphic information data sets to provide a
Aeromagnetic Survey At Lightning Dock Area (Warpinski, Et Al., 2002) | Open
2) 2) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Aeromagnetic Survey At Lightning Dock Area (Warpinski, Et Al., 2002) Exploration Activity Details Location Lightning Dock Area Exploration Technique Aeromagnetic Survey Activity Date Usefulness not indicated DOE-funding Unknown Notes As a foundation for successful siting and drilling a deep test well, additional geophysical work has been completed including gravity, resistivity, and airborne magnetic surveys. Several new seismic profiles are planned to provide more focused siting and drilling plans. These new geophysical surveys are being integrated into the combined thermal, hydrologic, and subsurface stratigraphic information data sets to provide a comprehensive integrated geothermal model. From all of this information,
Aeromagnetic Survey At Mokapu Penninsula Area (Thomas, 1986) | Open Energy
Aeromagnetic Survey At Mokapu Penninsula Area (Thomas, 1986) Aeromagnetic Survey At Mokapu Penninsula Area (Thomas, 1986) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Aeromagnetic Survey At Mokapu Penninsula Area (Thomas, 1986) Exploration Activity Details Location Mokapu Penninsula Area Exploration Technique Aeromagnetic Survey Activity Date Usefulness not indicated DOE-funding Unknown Notes A separate geophysical analysis performed on the Koolau caldera area (Kauahikaua, 1981 a) synthesized existing self-potential, gravity, seismic and aeromagnetic data with recently acquired resistivity soundings. An analysis of the observed remnant magnetization within the caldera complex suggested that subsurface temperatures ranged from less than 300degrees C to no more than 540degrees C. The resistivity data indicated that the
A perspective on Quantum Gravity Phenomenology
I give a brief overview of some Quantum-Gravity-Phenomenology research lines, focusing on studies of cosmic rays and gamma-ray bursts that concern the fate of Lorentz symmetry in quantum spacetime. I also stress that the most valuable phenomenological analyses should not mix too many conjectured new features of quantum spacetime, and from this perspective it appears that it should be difficult to obtain reliable guidance on the quantum-gravity problem from the analysis of synchrotron radiation from the Crab nebula and from the analysis of phase coherence of light from extragalactic sources. Forthcoming observatories of ultra-high-energy neutrinos should provide several opportunities for clean tests of some simple hypothesis for the short-distance structure of spacetime. In particular, these neutrino studies, and some related cosmic-ray studies, should provide access to the regime $E>\\sqrt{m E_p}$.
Giovanni Amelino-Camelia
Black Holes in Three Dimensional Topological Gravity
We investigate the black hole solution to (2+1)-dimensional gravity coupled to topological matter, with a vanishing cosmological constant. We calculate the total energy, angular momentum and entropy of the black hole in this model and compare with results obtained in Einstein gravity. We find that the theory with topological matter reverses the identification of energy and angular momentum with the parameters in the metric, compared with general relativity, and that the entropy is determined by the circumference of the inner rather than the outer horizon. We speculate that this results from the contribution of the topological matter fields to the conserved currents. We also briefly discuss two new possible (2+1)-dimensional black holes.
S. Carlip; J. Gegenberg; R. B. Mann
Hydrogen atom in Palatini theories of gravity
We study the effects that the gravitational interaction of $f(R)$ theories of gravity in Palatini formalism has on the stationary states of the Hydrogen atom. We show that the role of gravity in this system is very important for lagrangians $f(R)$ with terms that grow at low curvatures, which have been proposed to explain the accelerated expansion rate of the universe. We find that new gravitationally induced terms in the atomic Hamiltonian generate a strong backreaction that is incompatible with the very existence of bound states. In fact, in the 1/R model, Hydrogen disintegrates in less than two hours. The universe that we observe is, therefore, incompatible with that kind of gravitational interaction. Lagrangians with high curvature corrections do not lead to such instabilities.
Gonzalo J. Olmo
Modified Gravity via Spontaneous Symmetry Breaking
We construct effective field theories in which gravity is modified via spontaneous breaking of local Lorentz invariance. This is a gravitational analogue of the Higgs mechanism. These theories possess additional graviton modes and modified dispersion relations. They are manifestly well-behaved in the UV and free of discontinuities of the van Dam-Veltman-Zakharov type, ensuring compatibility with standard tests of gravity. They may have important phenomenological effects on large distance scales, offering an alternative to dark energy. For the case in which the symmetry is broken by a vector field with the wrong sign mass term, we identify four massless graviton modes (all with positive-definite norm for a suitable choice of a parameter) and show the absence of the discontinuity.
B. M. Gripaios
Holographic Superconductivity with Gauss-Bonnet gravity
I review recent work on holographic superconductivity with Einstein-Gauss-Bonnet gravity, and show how the critical temperature of the superconductor depends on both gravitational backreaction and the Gauss-Bonnet parameter, using both analytic and numerical arguments. I also review computations of the conductivity, finding the energy gap, and demonstrating that there is no universal gap ratio, $\\omega_g/T_c$, for these superconductors.
Ruth Gregory
Gravity controlled anti-reverse rotation device
A gravity assisted anti-reverse rotation device for preventing reverse rotation of pumps and the like. A horizontally mounted pawl is disposed to mesh with a fixed ratchet preventing reverse rotation when the pawl is advanced into intercourse with the ratchet by a vertically mounted lever having a lumped mass. Gravitation action on the lumped mass urges the pawl into mesh with the ratchet, while centrifugal force on the lumped mass during forward, allowed rotation retracts the pawl away from the ratchet.
Dickinson, Robert J. (Shaler Township, Allegheny County, PA); Wetherill, Todd M. (Lower Burrell, PA)
1 Quantum Gravity and Regge Calculus
This is an informal review of the formulation of canonical general relativity and of its implications for quantum gravity; the various versions are compared, both in the continuum and in a discretized approximation suggested by Regge calculus. I also show that the weakness of the link with the geometric content of the theory gives rise to what I think is a serious flaw in the claimed derivation of a discrete structure for space at the quantum level. 1.
Giorgio Immirzi A
Twisted covariant noncommutative self-dual gravity
A twisted covariant formulation of noncommutative self-dual gravity is presented. The formulation for constructing twisted noncommutative Yang-Mills theories is used. It is shown that the noncommutative torsion is solved at any order of the {theta} expansion in terms of the tetrad and some extra fields of the theory. In the process the first order expansion in {theta} for the Plebanski action is explicitly obtained.
Estrada-Jimenez, S.; Garcia-Compean, H.; Obregon, O.; Ramirez, C. [Centro de Estudios en Fisica y Matematicas Basicas y Aplicadas, Universidad Autonoma de Chiapas, Calle 4 Oriente Norte 1428, Tuxtla Gutierrez, Chiapas (Mexico); Departamento de Fisica, Centro de Investigacion y de Estudios Avanzados del IPN, P.O. Box 14-740, 07000 Mexico D.F. (Mexico); Centro de Investigacion y de Estudios Avanzados del IPN, Unidad Monterrey, PIIT, Via del Conocimiento 201, Autopista nueva al Aeropuerto km 9.5, 66600, Apodaca Nuevo Leon (Mexico); Instituto de Fisica de la Universidad de Guanajuato, P.O. Box E-143, 37150, Leon Gto. (Mexico); Facultad de Ciencias Fisico Matematicas, Universidad Autonoma de Puebla, P.O. Box 1364, 72000, Puebla (Mexico)
Distinguishing Modified Gravity from Dark Energy
The acceleration of the universe can be explained either through dark energy or through the modification of gravity on large scales. In this paper we investigate modified gravity models and compare their observable predictions with dark energy models. Modifications of general relativity are expected to be scale-independent on super-horizon scales and scale-dependent on sub-horizon scales. For scale-independent modifications, utilizing the conservation of the curvature scalar and a parameterized post-Newtonian formulation of cosmological perturbations, we derive results for large scale structure growth, weak gravitational lensing, and cosmic microwave background anisotropy. For scale-dependent modifications, inspired by recent $f(R)$ theories we introduce a parameterization for the gravitational coupling $G$ and the post-Newtonian parameter $\\gamma$. These parameterizations provide a convenient formalism for testing general relativity. However, we find that if dark energy is generalized to include both entropy and shear stress perturbations, and the dynamics of dark energy is unknown a priori, then modified gravity cannot in general be distinguished from dark energy using cosmological linear perturbations.
Edmund Bertschinger; Phillip Zukin
Supermassive galactic centre with repulsive gravity
Repulsive gravity has its origin in the 1939 article of Oppenheimer and Snyder which describes a collapsar, that is an idealized star of non-interacting material (dust) collapsing under its own gravity. The stellar material has a final state resembling a football, that is a significant part of it is concentrated in a thin surface shell. An interior pressure is exerted by the strong gravitational field, equivalent to a negative mass. However, the OS solution has been misunderstood, the shell's position being incorrectly identified with the "event horizon" in black-hole theory. While half the material is concentrated in a shell occupying a small fraction of the radius, some material is spread throughout the interior, unlike the concentration in a black hole's singularity. We deal with the singularity in density at the shell surface, by including Fermi pressure of degenerate electrons for a shell density comparable to a solar mass-sized white dwarf. Because the high-density region is concentrated in a shell, instead of at the centre as in a black hole, our conclusion is that repulsive gravity enables the existence of supermassive white dwarfs.
Trevor W. Marshall; Max K. Wallis
Primordial nucleosynthesis in conformal Weyl gravity
Recently conformal Weyl gravity has been considered as a candidate alternative gravity theory. This fourth-order theory is attractive because it is the only metric theory of gravity which is invariant under local conformal transformations of the metric. The authors calculate the primordial light element abundances in this theory. The major difference from the standard cosmology is that the universe expands far more slowly throughout the nucleosynthesis epoch. The production of {sup 4}He depends strongly on {eta}, the ratio of baryons to photons. For {eta} = 10{sup {minus}8} the mass fraction of {sup 4}He is X{sub 4} {approx_equal} 0.25 and the number densities relative to hydrogen for {sup 2}H, {sup 3}He and {sup 7}Li are n({sup 2}H)/n(H) {approx_equal} 9 {times} 10{sup {minus}20}, n({sup 3}He)/n(H) {approx_equal}4 {times} 10{sup {minus}18} and n({sup 7}Li)/n(H) {approx_equal} 10{sup {minus}13}. This value of {eta} corresponds to a baryon mass density close to the standard model critical density. However, adjusting {eta} to give a reasonable helium yield forces the deuterium and lithium yields to be small enough that the theory cannot be reconciled with observations.
Knox, L.; Kosowsky, A. [Univ. of Chicago, IL (United States). Enrico Fermi Inst.]|[Fermi National Accelerator Lab., Batavia, IL (United States)
Lorentz covariance of loop quantum gravity
The kinematics of loop gravity can be given a manifestly Lorentz-covariant formulation: the conventional SU(2)-spin-network Hilbert space can be mapped to a space K of SL(2,C) functions, where Lorentz covariance is manifest. K can be described in terms of a certain subset of the projected spin networks studied by Livine, Alexandrov and Dupuis. It is formed by SL(2,C) functions completely determined by their restriction on SU(2). These are square-integrable in the SU(2) scalar product, but not in the SL(2,C) one. Thus, SU(2)-spin-network states can be represented by Lorentz-covariant SL(2,C) functions, as two-component photons can be described in the Lorentz-covariant Gupta-Bleuler formalism. As shown by Wolfgang Wieland in a related paper, this manifestly Lorentz-covariant formulation can also be directly obtained from canonical quantization. We show that the spinfoam dynamics of loop quantum gravity is locally SL(2,C)-invariant in the bulk, and yields states that are precisely in K on the boundary. This clarifies how the SL(2,C) spinfoam formalism yields an SU(2) theory on the boundary. These structures define a tidy Lorentz-covariant formalism for loop gravity.
Rovelli, Carlo; Speziale, Simone [Centre de Physique Theorique de Luminy, Case 907, F-13288 Marseille (France)
Flipped spinfoam vertex and loop gravity
We introduce a vertex amplitude for 4d loop quantum gravity. We derive it from a conventional quantization of a Regge discretization of euclidean general relativity. This yields a spinfoam sum that corrects some difficulties of the Barrett-Crane theory. The second class simplicity constraints are imposed weakly, and not strongly as in Barrett-Crane theory. Thanks to a flip in the quantum algebra, the boundary states turn out to match those of SO(3) loop quantum gravity -- the two can be identified as eigenstates of the same physical quantities -- providing a solution to the problem of connecting the covariant SO(4) spinfoam formalism with the canonical SO(3) spin-network one. The vertex amplitude is SO(3) and SO(4)-covariant. It rectifies the triviality of the intertwiner dependence of the Barrett-Crane vertex, which is responsible for its failure to yield the correct propagator tensorial structure. The construction provides also an independent derivation of the kinematics of loop quantum gravity and of the result that geometry is quantized.
Jonathan Engle; Roberto Pereira; Carlo Rovelli
The Gravity Dual of the Ising Model
We evaluate the partition function of three dimensional theories of gravity in the quantum regime, where the AdS radius is Planck scale and the central charge is of order one. The contribution from the AdS vacuum sector can - with certain assumptions - be computed and equals the vacuum character of a minimal model CFT. The torus partition function is given by a sum over geometries which is finite and computable. For generic values of Newton's constant G and the AdS radius L the result has no Hilbert space interpretation, but in certain cases it agrees with the partition function of a known CFT. For example, the partition function of pure Einstein gravity with G=3L equals that of the Ising model, providing evidence that these theories are dual. We also present somewhat weaker evidence that the 3-state and tricritical Potts models are dual to pure higher spin theories of gravity based on SL(3) and E_6, respectively.
Alejandra Castro; Matthias R. Gaberdiel; Thomas Hartman; Alexander Maloney; Roberto Volpato
Castro, Alejandra; Hartman, Thomas; Maloney, Alexander; Volpato, Roberto
A model of accelerating dark energy in decelerating gravity
The expansion of the Universe is accelerated as testified by observations of SNeIa at varying redshifts. Explanations of this acceleration are of two kinds: modifications of Einstein gravity or new forms of energy. An example of modified gravity is the braneworld Dvali-Gabadadze-Porrati (DGP) model, an example of dark energy is Chaplygin gas. Both are characterized by a cross-over length scale $r_c$ which marks the transition between physics occurring on our four-dimensional brane, and in a five-dimensional bulk space. Assuming that the scales $r_c$ in the two models are the same, we study Chaplygin gas dark energy in flat DGP geometries. The self-accelerating branch does not give a viable model, it causes too much acceleration. We derive the Hubble function and the luminosity distance for the self-decelerating branch, and then fit a compilation of 192 SNeIa magnitudes and redshifts in the space of the three parameters of the model. Our model with the self-decelerating branch fits the supernova data as successfully as does the $\\Lambda CDM$ model, and with only one additional parameter. In contrast to the $\\Lambda CDM$ model, this model needs no fine-tuning, and it can explain the coincidence problem. It is unique in the sense that it cannot be reduced to a cosmological constant model in any other limit of the parameter space than in the distant future. If later tests with other cosmological data are successful, we have here a first indication that we live in a five-dimensional braneworld.
M. Roos
A Proposed Alternative Low Energy Quantum Field Theory of Gravity Based on a Bose-Einstein Condensate Effect
An alternative quantum field theory for gravity is proposed for low energies based on an attractive effect between contaminants in a Bose-Einstein Condensate rather than on particle exchange. In the ``contaminant in condensate effect," contaminants cause a potential in an otherwise uniform condensate, forcing the condensate between two contaminants to a higher energy state. The energy of the system decreases as the contaminants come closer together, causing an attractive force between contaminants. It is proposed that mass-energy may have a similar effect on Einstein's space-time field, and gravity is quantized by the same method by which the contaminant in condensate effect is quantized. The resulting theory is finite and, if a physical condensate is assumed to underly the system, predictive. However, the proposed theory has several flaws at high energies and is thus limited to low energies. Falsifiable predictions are given for the case that the Higgs condensate is assumed to be the condensate underlying gravity.
Alexander Oshmyansky
and Completing Assigned Survey and Completing Assigned Survey © 2011 SuccessFactors, Inc. - 1 - SuccessFactors Learning Confidential. All rights reserved. Job Aid: Launching and Completing Assigned Survey Purpose The purpose of this job aid is to guide users through the step-by-step process of launching and completing assigned surveys. Task A. Launch and Complete Assigned Survey From the Home page, filter the To-Do List to show only Surveys. Hover over the course evaluation title. Click Open. 1 2 3 3 2 1 Launch and Complete Assigned Survey 6 Steps Task A SuccessFactors Learning v 6.4 User Job Aid Launching and Completing Assigned Survey © 2011 SuccessFactors, Inc. - 2 - SuccessFactors Learning Complete the survey by selecting the radio button for the appropriate rating
SDSS spectroscopic survey of stars
In addition to optical photometry of unprecedented quality, the Sloan Digital Sky Survey (SDSS) is also producing a massive spectroscopic database. We discuss determination of stellar parameters, such as effective temperature, gravity and metallicity from SDSS spectra, describe correlations between kinematics and metallicity, and study their variation as a function of the position in the Galaxy. We show that stellar parameter estimates by Beers et al. show a good correlation with the position of a star in the g-r vs. u-g color-color diagram, thereby demonstrating their robustness as well as a potential for photometric parameter estimation methods. Using Beers et al. parameters, we find that the metallicity distribution of the Milky Way stars at a few kpc from the galactic plane is bimodal with a local minimum at [Z/Zo]~ -1.3. The median metallicity for the low-metallicity [Z/Zo] -1.3 sample. We also find that the low-metallicity sample has ~2.5 times larger velocity dispersion and that it does not rotate (at ...
Ivezic, Z; Uomoto, A; Bond, N; Beers, T; Allende-Prieto, C; Wilhelm, R; Lee, Y S; Sivarani, T; Juric, M; Lupton, R; Rockosi, C M; Knapp, G; Gunn, J; Yanny, B; Jester, S; Kent, S; Pier, J; Munn, J A; Richards, G; Newberg, H; Blanton, M; Eisenstein, D; Hawley, S; Anderson, S; Harris, H; Kiuchi, F; Chen, A; Bushong, J; Sohi, H; Haggard, D; Kimball, A; Barentine, J; Brewington, H; Harvanek, M; Kleinman, S; Krzes�nski, J; Long, D; Nitta, A; Snedden, S A
In addition to optical photometry of unprecedented quality, the Sloan Digital Sky Survey (SDSS) is also producing a massive spectroscopic database. We discuss determination of stellar parameters, such as effective temperature, gravity and metallicity from SDSS spectra, describe correlations between kinematics and metallicity, and study their variation as a function of the position in the Galaxy. We show that stellar parameter estimates by Beers et al. show a good correlation with the position of a star in the g-r vs. u-g color-color diagram, thereby demonstrating their robustness as well as a potential for photometric parameter estimation methods. Using Beers et al. parameters, we find that the metallicity distribution of the Milky Way stars at a few kpc from the galactic plane is bimodal with a local minimum at [Z/Zo]~ -1.3. The median metallicity for the low-metallicity [Z/Zo] -1.3 sample. We also find that the low-metallicity sample has ~2.5 times larger velocity dispersion and that it does not rotate (at the ~10 km/s level), while the rotational velocity of the high-metallicity sample decreases smoothly with the height above the galactic plane.
Z. Ivezic; D. Schlegel; A. Uomoto; N. Bond; T. Beers; C. Allende Prieto; R. Wilhelm; Y. Sun Lee; T. Sivarani; M. Juric; R. Lupton; C. Rockosi; G. Knapp; J. Gunn; B. Yanny; S. Jester; S. Kent; J. Pier; J. Munn; G. Richards; H. Newberg; M. Blanton; D. Eisenstein; S. Hawley; S. Anderson; H. Harris; F. Kiuchi; A. Chen; J. Bushong; H. Sohi; D. Haggard; A. Kimball; J. Barentine; H. Brewington; M. Harvanek; S. Kleinman; J. Krzesinski; D. Long; A. Nitta; S. Snedden; for the SDSS Collaboration
ORISE: Characterization surveys
Characterization surveys Characterization surveys An ORISE technicians performs a characterization survey The Oak Ridge Institute for Science and Education (ORISE) performs independent, objective characterization surveys to define the extent of radiological contamination at sites scheduled for decontamination and decommissioning (D&D). A fundamental aspect of all D&D projects, characterization surveys provide guidance to determine the best remediation procedures and are a cost-effective method of ensuring a site meets preliminary regulatory standards. ORISE designs characterization surveys using the data quality objectives process. This approach focuses on the particular objective of characterization, and ensures that only the data needed to address the characterization decisions are collected. Data collection efforts are
More about spontaneous Lorentz-violation and infrared modification of gravity
We consider a model with Lorentz-violating vector field condensates, in which dispersion laws of all perturbations, including tensor modes, undergo non-trivial modification in the infrared. The model is free of ghosts and tachyons at high 3-momenta. At low 3-momenta there are ghosts, and at even lower 3-momenta there exist tachyons. Still, with appropriate choice of parameters, the model is phenomenologically acceptable. Beyond a certain large distance scale and even larger time scale, the gravity of a static source changes from that of General Relativity to that of van Dam--Veltman--Zakharov limit of the Fierz--Pauli theory. Yet the late time cosmological evolution is always determined by the standard Friedmann equation, modulo small correction to the ``cosmological Planck mass'', so the modification of gravity cannot by itself explain the accelerated expansion of the Universe. We argue that the latter property is generic in a wide class of models with condensates.
M. V. Libanov; V. A. Rubakov
New Agegraphic Dark Energy in $f(R)$ Gravity
In this paper we study cosmological application of new agegraphic dark energy density in the $f(R)$ gravity framework. We employ the new agegraphic model of dark energy to obtain the equation of state for the new agegraphic energy density in spatially flat universe. Our calculation show, taking $nenergy model in flat universe in the modified gravity cosmology framework. Also we develop a reconstruction scheme for the modified gravity with $f(R)$ action.
Setare, M R
M. R. Setare
AdS waves as exact solutions to quadratic gravity
We give an exact solution of the quadratic gravity in D dimensions. The solution is a plane-fronted wave metric with a cosmological constant. This metric solves not only the full quadratic gravity field equations but also the linearized ones which include the linearized equations of the recently found critical gravity. A subset of the solutions change the asymptotic structure of the anti-de Sitter space due to their logarithmic behavior.
Guellue, Ibrahim; Sisman, Tahsin Cagri; Tekin, Bayram [Department of Physics, Middle East Technical University, 06531 Ankara (Turkey); Guerses, Metin [Department of Mathematics, Faculty of Sciences Bilkent University, 06800 Ankara (Turkey)
Gravity Couplings in the Standard-Model Extension
The Standard-Model Extension (SME) is an action-based expansion describing general Lorentz violation for known matter and fields, including gravity. In this talk, I will discuss the Lorentz-violating gravity couplings in the SME. Toy models that match the SME expansion, including vector and two-tensor models, are reviewed. Finally I discuss the status of experiments and observations probing gravity coefficients for Lorentz violation.
Bailey, Quentin G
Talking Peace: A Population-Based Survey on Attitudes about Security, Dispute Resolution, and Post-Conflict Reconstruction in Liberia
data collection and interview techniques. Limitations At thethe study, survey and interview techniques, use of the PDA,
Vinck, Patrick; Pham, Phuong N.; Kreutzer, Tino
Exercise protocols during short-radius centrifugation for artificial gravity
Long-duration spaceflight results in severe physiological deconditioning, threatening the success of interplanetary travel. Exercise combined with artificial gravity provided by centrifugation may be the comprehensive ...
Reconstruction of modified gravity with ghost dark energy models
In this work, we reconstruct the $f(R)$ modified gravity for different ghost and generalized ghost dark energy models in FRW flat universe, which describe the accelerated expansion of the universe. The equation of state of reconstructed $f(R)$ - gravity has been calculated. We show that the corresponding $f(R)$ gravity of ghost dark energy model can behave like phantom or quintessence. We also show that the equation of state of reconstructed $f(R)$ gravity for generalized ghost model can transit from quintessence regime to the phantom regime as indicated by recent observations.
Khodam-Mohammadi, A
Effect of Centrifugal And Gravity Casting Technique over ...
In this work an attempt is made to study the effect of centrifugal and gravity casting ... A Minimum Pollution, Low Energy Process for the Recovery of Cobalt and�...
Lorentz Invariant phenomenological model of quantum gravity: A minimalistic presentation
The purpose of this paper is to give a minimalistic and self-contained presentation of a Lorentz Invariant phenomenological model of Quantum Gravity.
Bonder, Yuri [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico Apartado Postal 70-543, Distrito Federal 04510 (Mexico)
Hidden Lorentz symmetry of the Horava - Lifshitz gravity
In this letter it is shown that the Horava-Lifshitz gravity theory admits Lorentz symmetry preserving preferred global time foliation of the spacetime.
Jakub Rembielinski
Gravity wave coupling of the lower and middle atmosphere.
??A method of inferring tropospheric gravity wave source characteristics from middle atmosphere observations has been adapted from previous studies for use with MF radar observations� (more)
Love, Peter Thomas
Jefferson Lab Science Series - Detecting Einstein's Gravity Waves
Science Series Video Archive Next Video (Symmetry) Symmetry Detecting Einstein's Gravity Waves Dr. David Shoemaker - Massachusetts Institute of Technology March 18, 1997 LIGO...
Effects of Gravity on the Columnar to Equiaxed Transition in ...
The effects of gravity, thermal natural convection and dendrite transport were integrated into the model. Simulations of vertical directional solidification of an�...
Gravity in Randall-Sundrum two D-brane model
We analyse Randall-Sundrum two D-brane model by linear perturbation and then consider the linearised gravity on the D-brane. The qualitative contribution from the Kaluza-Klein modes of gauge fields to the coupling to the gravity on the brane will be addressed. As a consequence, the gauge fields localised on the brane are shown not to contribute to the gravity on the brane at large distances. Although the coupling between gauge fields and gravity appears in the next order, the ordinary coupling cannot be realised.
Tetsuya Shiromizu; Keitaro Takahashi; Yoshiaki Himemoto; Shuto Yamamoto
The Link Between Gravity Recovery and Hydrometallurgy - TMS
Aug 1, 2003 ... The Link Between Gravity Recovery and Hydrometallurgy: The Case of Gold by A.R. Laplante and W. Staunton�...
Can gravity be added to Pilot Wave models?
The purpose of this paper is to come up with one of the many possible schemes of "adding" gravity to Pilot Wave models.
Sverdlov, Roman
Evolution of Gold Gravity Recovery in Grinding Circuits - A Critical ...
Presentation Title, Evolution of Gold Gravity Recovery in Grinding Circuits - A Critical .... Selective Separations of Gold and Contaminants from Various Gold and�...
Polytropic and Chaplygin f(R)-gravity models
We reconstruct different f(R)-gravity models corresponding to the polytropic, standard Chaplygin, generalized Chaplygin, modified Chaplygin and modified variable Chaplygin gas dark energy models. We also obtain the equation of state parameters of the corresponding f(R)-gravity models which describe the accelerated expansion of the universe. We conclude that although the equation of state parameters of the obtained f(R)-gravities can behave like phantom or quintessence dark energy models, they cannot justify the transition from the quintessence state to the phantom regime. Furthermore, the polytropic and Chaplygin f(R)-gravity models in de Sitter space can satisfy the inflation condition.
K. Karami; M. S. Khaledian
Quantum Theory at Planck Scale, Limiting Values, Deformed Gravity and Dark Energy Problem
Within a theory of the existing fundamental length on the order of Planck's a high-energy deformation of the General Relativity for the space with horizon has been constructed. On this basis, Markov's work of the early eighties of the last century has been given a new interpretation to show that the heuristic model considered by him may be placed on a fundamental footing. The obtained results have been applied to solving of the dark energy problem, making it possible to frame the following hypothesis: a dynamic cosmological term is a measure of deviation from a thermodynamic identity (the first law of thermodynamics) of the high-energy (Planck's) deformation of Einstein equations for horizon spaces in their thermodynamic interpretation.
A. E. Shalyt-Margolin
10 Appendices Appendix 1. Glossary of Terminology and Definitions 11 Appendix 2. Survey Definitions. There is a Glossary of Terminology and Definitions (Appendix 1). The survey form is Appendix 3 of this Report
Hydrocarbon prospect mapping using balanced cross sections and gravity modeling, Onin and Kumawa Peninsulas, Irian Jaya, Indonesia
Exploration field geology mapping and acquisition of gravity data has been conducted on 26 surveyed traverse lines totaling approximately 650 line km across the Onin and Kumawa peninsulas of western Irian Jaya. The predominant surface outcrop is karstified New Guinea Limestone with a maximum thickness of 2150 m, which precludes the use of seismic data. The integrated use of field geology data, balanced cross sections, and gravity modeling has, however, enabled identification of two giant hydrocarbon prospects. The Onin and Kumawa peninsulas lie at the margin of Jurassic age rift faulting associated with the Australian northwest shelf. Jurassic rift sands of the Lower Kembelangan Formation are the primary reservoir target. During the Pliocene-Pleistocene collision of the Australian plate and the Banda are inverted sections of the rift system including the Onin and Kumawa peninsulas. A better understanding of the regional structure was gained by integrating the Mobil Oil gravity data (1992) and that collected by Shell Oil in the 1950s in the structurally less-deformed Bomberai region east of Onin and Kumawa. Bouguer reduction was carried out using a density of 2.4 gm/cc and GRS67 and IGSN71 formulas. Spectral analyses indicate that basement is at a depth of about 3 km in the Onin area and at about 6 km in the Bomberai area. The Bomberai and Onin-Kumawa regions are separated from one another by a steep southeast-southwest-striking gravity gradient, which may mark a change of lithology.
Untung, M.; Budiman, S.I.; Nasution, J.; Mirnanda, E. (Geological Research and Development Centre, Bandung (Indonesia)); Sirodj, E.G.; Henage, L.F. (Mobil Oil Indonesia, Jakarta (Indonesia))
Testing general scalar-tensor gravity and massive gravity with cluster lensing
We explore the possibility of testing modified gravity exhibiting the Vainshtein mechanism against observations of cluster lensing. We work in the most general scalar-tensor theory with second-order field equations (Horndeski's theory), and derive static and spherically symmetric solutions, for which the scalar field is screened below a certain radius. It is found that the essential structure of the problem in the most general case can be captured by the program of classifying Vainshtein solutions out of different solutions to a quintic equation, as has been performed in the context of massive gravity. The key effect on gravitational lensing is that the second derivative of the scalar field can substantially be large at the transition from screened to unscreened regions, leaving a dip in the convergence. This allows us to put observational constraints on parameters characterizing the general scalar-tensor modification of gravity. We demonstrate how this occurs in massive gravity as an example, and discuss its observational signatures in cluster lensing.
Tatsuya Narikawa; Tsutomu Kobayashi; Daisuke Yamauchi; Ryo Saito
Conservation laws for vacuum tetrad gravity
Ten conservation laws in useful polynomial form are derived from a Cartan form and Exterior Differential System (EDS) for the tetrad equations of vacuum relativity. The Noether construction of conservation laws for well posed EDS is introduced first, and an illustration given, deriving 15 conservation laws of the free field Maxwell Equations from symmetries of its EDS. The Maxwell EDS and tetrad gravity EDS have parallel structures, with their numbers of dependent variables, numbers of generating 2-forms and generating 3-forms, and Cartan character tables all in the ratio of 1 to 4. They have 10 corresponding symmetries with the same Lorentz algebra, and 10 corresponding conservation laws.
Frank B. Estabrook
Conservation of energy and Gauss Bonnet gravity
It is shown how can be made the classification of all tensors constructed from the Riemann tensor that verify the conservation of gravitational energy momentum. More precisely we explain that there exists a unique tensor of degree n in the Riemann tensor and its contractions that verifies the conservation of energy. We show that this tensor, only because it obeys this degree n structure as well as energy conservation, two facts which are true in all dimensions, verifies in dimension 2n this striking particularity of being Euler gravity. We stick here to the case n=2 but explain briefly why the general case is similar.
Christophe Real
Gravity duals for non-relativistic CFTs
We attempt to generalize the AdS/CFT correspondence to non-relativistic conformal field theories which are invariant under Galilean transformations. Such systems govern ultracold atoms at unitarity, nucleon scattering in some channels, and more generally, a family of universality classes of quantum critical behavior. We construct a family of metrics which realize these symmetries as isometries. They are solutions of gravity with negative cosmological constant coupled to pressureless dust. We discuss realizations of the dust, which include a bulk superconductor. We develop the holographic dictionary and compute some two-point correlators. A strange aspect of the correspondence is that the bulk geometry has two extra noncompact dimensions.
Koushik Balasubramanian; John McGreevy
Bringing Together Gravity and the Quanta
Due to its underlying gauge structure, teleparallel gravity achieves a separation between inertial and gravitational effects. It can, in consequence, describe the isolated gravitational interaction without resorting to the equivalence principle, and is able to provide a tensorial definition for the energy-momentum density of the gravitational field. Considering the conceptual conflict between the local equivalence principle and the nonlocal uncertainty principle, the replacement of general relativity by its teleparallel equivalent can be considered an important step towards a prospective reconciliation between gravitation and quantum mechanics.
R. Aldrovandi; L. C. T. Guillen; J. G. Pereira; K. H. Vu
The dualities of 3D dilaton gravity
We investigate Brans-Dicke dilaton gravity theories in 2+1 dimensions. We show that the reduced field equations for solutions with diagonal metric and depending only on one spacetime coordinate have a continuous O(2) symmetry. Using this symmetry we derive general static and cosmological solutions of the theory. The action of the discrete group O(2,Z) on the space of the solutions is discussed. Three-dimensional string effective theory and three-dimensional general relativity are discussed in detail. In particular, we find that the previously discovered black string solution is dual to a spacetime with a conical singularity.
Maxwell's equations, linear gravity, and twistors
A detailed outline is presented of several convergent points of view connecting the self-dual and anti-self-dual fields with their free data. This is doen for the Maxwell and for linearized gravity as exemplifying the approaches. The Sparling equation provides one tool of great power and characterizes one approach. The twistor theory of Penrose yields another equally powerful point of view. The links between these two basic approaches given in this paper provide a unification that allows workers and others with interest in this area to proceed more readily toward the goal of understanding the full nonlinear Einstein equations.
Kozameh, C.N.; Newman, E.T.; Porter, J.R.
Lorentz Invariance Violation in Modified Gravity
We consider an environmentally dependent violation of Lorentz invariance in scalar-tensor models of modified gravity where General Relativity is retrieved locally thanks to a screening mechanism. We find that fermions have a modified dispersion relation and would go faster than light in an anisotropic and space-dependent way along the scalar field lines of force. We analyse briefly the OPERA results and show that they could be reproduced with chameleon models. We suggest that neutrinos emitted radially, at different energies, and observed on the other side of the earth would provide a test of these models.
Brax, Philippe
Seven-Dimensional Gravity with Topological Terms
We construct new seven-dimensional gravity by adding two topological terms to the Einstein-Hilbert action. For certain choice of the coupling constants, these terms may be related to the R^4 correction to the 3-form field equation of eleven-dimensional supergravity. We derive the full set of the equations of motion. We find that the static spherically-symmetric black holes are unmodified by the topological terms. We obtain squashed AdS_7, and also squashed seven spheres and Q^{111} spaces in Euclidean signature.
H. Lu; Yi Pang
Gamma Ray Burst Neutrinos Probing Quantum Gravity
Very high energy, short wavelength, neutrinos may interact with the space-time foam predicted by theories of quantum gravity. They would propagate like light through a crystal lattice and be delayed, with the delay depending on the energy. This will appear to the observer as a violation of Lorenz invariance. Back of the envelope calculations imply that observations of neutrinos produced by gamma ray bursts may reach Planck-scale sensitivity. We revisit the problem considering two essential complications: the imprecise timing of the neutrinos associated with their poorly understood production mechanism in the source and the indirect nature of their energy measurement made by high energy neutrino telescopes.
M. C. Gonzalez-Garcia; F. Halzen
Hall viscosity from gauge/gravity duality
In (2+1)-dimensional systems with broken parity, there exists yet another transport coefficient, appearing at the same order as the shear viscosity in the hydrodynamic derivative expansion. In condensed matter physics, it is referred to as "Hall viscosity". We consider a simple holographic realization of a (2+1)-dimensional isotropic fluid with broken spatial parity. Using techniques of fluid/gravity correspondence, we uncover that the holographic fluid possesses a nonzero Hall viscosity, whose value only depends on the near-horizon region of the background. We also write down a Kubo's formula for the Hall viscosity. We confirm our results by directly computing the Hall viscosity using the formula.
Omid Saremi; Dam Thanh Son
Thermodynamics of 5D dilaton-gravity
We calculate the free energy, spatial string tension and Polyakov loop of the gluon plasma using the dilaton potential of Ref. [1] in the dilaton-gravity theory of AdS/QCD. The free energy is computed from the Black Hole solutions of the Einstein equations in two ways: first, from the Bekenstein-Hawking proportionality of the entropy with the area of the horizon, and secondly from the Page-Hawking computation of the free energy. The finite temperature behaviour of the spatial string tension and Polyakov loop follow from the corresponding string theory in AdS{sub 5}. Comparison with lattice data is made.
Megias, E. [Institute for Theoretical Physics, University of Heidelberg (Germany); Instituto de Fisica Teorica CSIC-UAM, Universidad Autonoma de Madrid (Spain)
Robust approach to f(R) gravity
We consider metric f(R) theories of gravity without mapping them to their scalar-tensor counterpart, but using the Ricci scalar itself as an ''extra'' degree of freedom. This approach avoids then the introduction of a scalar-field potential that might be ill defined (not single valued). In order to explicitly show the usefulness of this method, we focus on static and spherically symmetric spacetimes and deal with the recent controversy about the existence of extended relativistic objects in certain class of f(R) models.
Jaime, Luisa G. [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Apartado Postal 70-543, Mexico Distrito Federal 04510 (Mexico); Facultad de Ciencias, Universidad Nacional Autonoma de Mexico, Apartado Postal 50-542, Mexico Distrito Federal 04510 (Mexico); Patino, Leonardo [Facultad de Ciencias, Universidad Nacional Autonoma de Mexico, Apartado Postal 50-542, Mexico Distrito Federal 04510 (Mexico); Salgado, Marcelo [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Apartado Postal 70-543, Mexico Distrito Federal 04510 (Mexico)
Principal facts for gravity stations in the Darrough Known Geothermal Resource Area (KGRA), Nevada
The latitude, longitude, elevation, observed gravity, theoretical gravity, terrain correction, free-air correction, Bougner correction, and Bougner anomaly are tabulated for 71 gravity stations in the Darrough KGRA, Nevada area. (WHK)
Peterson, D.L.; Dansereau, D.A.
Environmental Survey preliminary report
This report presents the preliminary findings from the first phase of the Environmental Survey of the United States Department of Energy (DOE) Sandia National Laboratories conducted August 17 through September 4, 1987. The objective of the Survey is to identify environmental problems and areas of environmental risk associated with Sandia National Laboratories-Albuquerque (SNLA). The Survey covers all environmental media and all areas of environmental regulation. It is being performed in accordance with the DOE Environmental Survey Manual. This phase of the Survey involves the review of existing site environmental data, observations of the operations carried on at SNLA, and interviews with site personnel. 85 refs., 49 figs., 48 tabs.
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Telluric Survey At Raft River Geothermal Area (1978) | Open Energy
Raft River Geothermal Area (1978) Raft River Geothermal Area (1978) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Telluric Survey At Raft River Geothermal Area (1978) Exploration Activity Details Location Raft River Geothermal Area Exploration Technique Telluric Survey Activity Date 1978 Usefulness not indicated DOE-funding Unknown Exploration Basis Infer the structure and the general lithology underlying the valley Notes The relative ellipse area contour map compiled from the telluric current survey generally conforms to the gravity map except for lower values in the area of the geothermal system. References Mabey, D.R.; Hoover, D.B.; O'Donnell, J.E.; Wilson, C.W. (1 December 1978) Reconnaissance geophysical studies of the geothermal system in southern Raft River Valley, Idaho
Vacuum energy: quantum hydrodynamics vs quantum gravity
We compare quantum hydrodynamics and quantum gravity. They share many common features. In particular, both have quadratic divergences, and both lead to the problem of the vacuum energy, which in the quantum gravity transforms to the cosmological constant problem. We show that in quantum liquids the vacuum energy density is not determined by the quantum zero-point energy of the phonon modes. The energy density of the vacuum is much smaller and is determined by the classical macroscopic parameters of the liquid including the radius of the liquid droplet. In the same manner the cosmological constant is not determined by the zero-point energy of quantum fields. It is much smaller and is determined by the classical macroscopic parameters of the Universe dynamics: the Hubble radius, the Newton constant and the energy density of matter. The same may hold for the Higgs mass problem: the quadratically divergent quantum correction to the Higgs potential mass term is also cancelled by the microscopic (trans-Planckian) degrees of freedom due to thermodynamic stability of the whole quantum vacuum.
G. E. Volovik
Infrared Surveys for AGN
From the earliest extragalactic infrared studies AGN have shown themselves to be strong infrared sources and IR surveys have revealed new populations of AGN. I briefly review current motivations for AGN surveys in the infrared and results from previous IR surveys. The Luminous Infrared Galaxies, which in some cases house dust-enshrouded AGN, submillimeter surveys, and recent studies of the cosmic x-ray and infrared backgrounds suggest that there is a population of highly-obscured AGN at high redshift. ISO Surveys have begun to resolve the infrared background and may have detected this obscured AGN population. New infrared surveys, particularly the SIRTF Wide-area Infrared Extragalactic Legacy Survey (SWIRE), will detect this population and provide a platform for understanding the evolution of AGN, Starbursts and passively evolving galaxies in the context of large-scale structure and environment.
Smith, H E
Harding E. Smith
Constraints on Dark Energy Models from Weak Gravity Conjecture
We study the constraints on the dark energy model with constant equation of state parameter $w=p/\\rho$ and the holographic dark energy model by using the weak gravity conjecture. The combination of weak gravity conjecture and the observational data gives $wenergy model realized by a scalar field is in swampland.
Chen, Ximing; Gong, Yungui
Ximing Chen; Jie Liu; Yungui Gong