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0707.3130
Jacek Dobaczewski
H. Zdunczuk, W. Satula, J. Dobaczewski, M. Kosmulski
Angular momentum projection of cranked Hartree-Fock states: Application to terminating bands in A~44 nuclei
9 RevTeX pages, 8 EPS figures, submitted to Physical Review C
Phys.Rev.C76:044304,2007
10.1103/PhysRevC.76.044304
null
nucl-th
null
We present the first systematic calculations based on the angular-momentum projection of cranked Slater determinants. We propose the Iy --> I scheme, by which one projects the angular momentum I from the 1D cranked state constrained to the average spin projection of <I_y>=I. Calculations performed for the rotational band in 46Ti show that the AMP Iy --> I scheme offers a natural mechanism for correcting the cranking moment of inertia at low-spins and shifting the terminating state up by ~2 MeV, in accordance with data. We also apply this scheme to high-spin states near the band termination in A~44 nuclei, and compare results thereof with experimental data, shell-model calculations, and results of the approximate analytical symmetry-restoration method proposed previously.
[ { "version": "v1", "created": "Fri, 20 Jul 2007 19:01:23 GMT" } ]
2008-12-18T00:00:00
[ [ "Zdunczuk", "H.", "" ], [ "Satula", "W.", "" ], [ "Dobaczewski", "J.", "" ], [ "Kosmulski", "M.", "" ] ]
0707.3131
Jan Arlt
T. Schulte, S. Drenkelforth, G. Kleine B\"uning, W. Ertmer, J. Arlt, M. Lewenstein, and L. Santos
Dynamics of Bloch Oscillations in Disordered Lattice Potentials
null
null
10.1103/PhysRevA.77.023610
null
cond-mat.other cond-mat.dis-nn
null
We present a detailed analysis of the dynamics of Bloch oscillations of Bose-Einstein condensates in disordered lattice potentials. Due to the disorder and the interparticle interactions these oscillations undergo a dephasing, reflected in a damping of the center of mass oscillations, which should be observable under realistic experimental conditions. The interplay between interactions and disorder is far from trivial, ranging from an interaction-enhanced damping due to modulational instability for strong interactions, to an interaction-reduced damping due to a dynamical screening of the disorder potential.
[ { "version": "v1", "created": "Fri, 20 Jul 2007 19:14:19 GMT" } ]
2009-11-13T00:00:00
[ [ "Schulte", "T.", "" ], [ "Drenkelforth", "S.", "" ], [ "Büning", "G. Kleine", "" ], [ "Ertmer", "W.", "" ], [ "Arlt", "J.", "" ], [ "Lewenstein", "M.", "" ], [ "Santos", "L.", "" ] ]
0707.3132
Sarah A. Yost
S. A. Yost, F. Aharonian, C. W. Akerlof, M. C. B. Ashley, S. Barthelmy, N. Gehrels, E. Gogus, T. Guver, D. Horns, U. Kiziloglu, H. A. Krimm, T. A. McKay, M. Ozel, A. Phillips, R. M. Quimby, G. Rowell, W. Rujopakarn, E. S. Rykoff, B. E. Schaefer, D. A. Smith, H. F. Swan, W. T. Vestrand, J. C. Wheeler, J. Wren, F. Yuan
The Dark Side of ROTSE-III Prompt GRB Observations
ApJ accepted. 20 pages in draft manuscript form, which includes 6 pages of tables and 2 figures
null
10.1086/521668
null
astro-ph
null
We present several cases of optical observations during gamma-ray bursts (GRBs) which resulted in prompt limits but no detection of optical emission. These limits constrain the prompt optical flux densities and the optical brightness relative to the gamma-ray emission. The derived constraints fall within the range of properties observed in GRBs with prompt optical detections, though at the faint end of optical/gamma flux ratios. The presently accessible prompt optical limits do not require a different set of intrinsic or environmental GRB properties, relative to the events with prompt optical detections.
[ { "version": "v1", "created": "Fri, 20 Jul 2007 19:18:08 GMT" } ]
2009-11-13T00:00:00
[ [ "Yost", "S. A.", "" ], [ "Aharonian", "F.", "" ], [ "Akerlof", "C. W.", "" ], [ "Ashley", "M. C. B.", "" ], [ "Barthelmy", "S.", "" ], [ "Gehrels", "N.", "" ], [ "Gogus", "E.", "" ], [ "Guver", "T.", "" ], [ "Horns", "D.", "" ], [ "Kiziloglu", "U.", "" ], [ "Krimm", "H. A.", "" ], [ "McKay", "T. A.", "" ], [ "Ozel", "M.", "" ], [ "Phillips", "A.", "" ], [ "Quimby", "R. M.", "" ], [ "Rowell", "G.", "" ], [ "Rujopakarn", "W.", "" ], [ "Rykoff", "E. S.", "" ], [ "Schaefer", "B. E.", "" ], [ "Smith", "D. A.", "" ], [ "Swan", "H. F.", "" ], [ "Vestrand", "W. T.", "" ], [ "Wheeler", "J. C.", "" ], [ "Wren", "J.", "" ], [ "Yuan", "F.", "" ] ]
0707.3133
Aparna Maybhate Dr.
A. Maybhate (STScI), P. Goudfrooij (STScI), F. Schweizer (OCIW), T. Puzia (HIA), and D. Carter (LJMU)
Evidence for Three Subpopulations of Globular Clusters in the Early-Type Post-Starburst Shell Galaxy AM 0139-655
35 pages, 12 figures, accepted for publication in AJ
Astron.J.134:1729-1739,2007
10.1086/521817
STScI e-print #1770
astro-ph
null
We present deep HST ACS images of the post-starburt shell galaxy AM 0139-655. We find evidence for the presence of three distinct globular cluster subpopulations associated with this galaxy: a centrally concentrated young population (~ 0.4 Gyr), an intermediate age population (~ 1 Gyr) and an old, metal-poor population similar to that seen around normal galaxies. The g-I color distribution of the clusters is bimodal with peaks at 0.85 and 1.35. The redder peak at g-I=1.35 is consistent with the predicted color for an old metal-poor population. The clusters associated with the peak at g-I=0.85 are centrally concentrated and interpreted as a younger and more metal-rich population. We suggest that these clusters have an age of ~ 0.4 Gyr and solar metallicity based on a comparison with population synthesis models. The luminosity function of these "blue" clusters is well represented by a power law. Interestingly, the brightest shell associated with the galaxy harbors some of the youngest clusters observed. This seems to indicate that the same merger event was responsible for the formation of both the shells and the young clusters. The red part of the color distribution contains several very bright clusters, which are not expected for an old, metal-poor population. Furthermore, the luminosity function of the "red" GCs cannot be fit well by either a single gaussian or a single power law. A composite (gaussian + power law) fit to the LF of the red clusters yields both a low rms and very plausible properties for an old population plus an intermediate-age population of GCs. Hence, we suggest that the red clusters in AM 0139-655 consist of two distinct GC subpopulations, one being an old, metal-poor population as seen in normal galaxies and one having formed during a recent dissipative galaxy merger.
[ { "version": "v1", "created": "Fri, 20 Jul 2007 19:19:59 GMT" } ]
2008-11-26T00:00:00
[ [ "Maybhate", "A.", "", "STScI" ], [ "Goudfrooij", "P.", "", "STScI" ], [ "Schweizer", "F.", "", "OCIW" ], [ "Puzia", "T.", "", "HIA" ], [ "Carter", "D.", "", "LJMU" ] ]
0707.3134
Stephen Adler
Stephen L. Adler and Fethi M. Ramazanoglu
Photon emission rate from atomic systems in the CSL model
LaTex 16pages; minor revisions in published version v3, Added Note in v4
J.Phys.A40:13395-13406,2007; J.Phys.A42:109801,2009
10.1088/1751-8113/40/44/017 10.1088/1751-8121/42/10/109801
null
quant-ph astro-ph hep-ph hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We calculate the photon emission rate from a general atomic system in the mass- proportional CSL model. For an isolated charged particle emitting kilovolt gamma rays, our results agree with those obtained by Fu. For a neutral atomic system, photon emission is strongly suppressed for photon wavelengths much larger than the atomic radius. However, for kilovolt gamma rays, Fu's result is modified by a structure factor that is of order unity, giving no rate suppression. Our calculation is readily generalized to the case of non-white noise, noise couplings that are not mass-proportional, and general (non-Gaussian) spatial correlation functions, and corresponding results are given. We briefly discuss the implications of our calculation for upper bounds on the CSL model parameters.
[ { "version": "v1", "created": "Fri, 20 Jul 2007 19:50:54 GMT" }, { "version": "v2", "created": "Thu, 20 Sep 2007 19:56:04 GMT" }, { "version": "v3", "created": "Mon, 24 Sep 2007 15:27:34 GMT" }, { "version": "v4", "created": "Wed, 26 Nov 2008 19:52:02 GMT" } ]
2009-02-20T00:00:00
[ [ "Adler", "Stephen L.", "" ], [ "Ramazanoglu", "Fethi M.", "" ] ]
0707.3135
Edward Shuryak
Shu Lin and Edward Shuryak
Stress Tensor of Static Dipoles in strongly coupled $\cal{N}$=4 Gauge Theory
null
Phys.Rev.D76:085014,2007
10.1103/PhysRevD.76.085014
null
hep-th
null
In the context of the AdS/CFT correspondence we calculate the induced stress tensor of static dipoles (electric-electric and electric-magnetic) in a strongly coupled ${\cal N}=4$ SYM gauge theory, by solving the linearized Einstein equation with Maldecena string as a source. Analytic expressions are given for the far-field and a near-field close to one charge, and compared to what one has in weak coupling. The result can be compared to lattice results for QCD-like theories in a deconfined but strongly coupled regime.
[ { "version": "v1", "created": "Fri, 20 Jul 2007 19:38:08 GMT" }, { "version": "v2", "created": "Thu, 16 Aug 2007 01:10:21 GMT" } ]
2008-11-26T00:00:00
[ [ "Lin", "Shu", "" ], [ "Shuryak", "Edward", "" ] ]
0707.3136
Lesser Blum
L. Blum and D.V. Perez Veloz
Towards an analytical theory for charged hard spheres
6 pages, 1 figure
null
null
null
cond-mat.soft cond-mat.stat-mech
null
Ion mixtures require an exclusion core to avoid collapse. The Debye Hueckel theory, where ions are point charges, is accurate only in the limit of infinite dilution. The MSA is the embedding of hard cores into DH, is valid for higher densities. In the MSA the properties of any ionic mixture can be represented by a single screening parameter $\Gamma$. For equal ionic size restricted model is obtained from the Debye parameter $\kappa$. This one parameter representation (BIMSA) is valid for complex and associating systems, such as the general n-polyelectrolytes. The BIMSA is the only theory that satisfies the infinite dilution limit of the DH theory for any chain length. The contact pair distribution function of hard ions mixture is a functional of $\Gamma$ and a small mean field parameter. This yields good agreement with the Monte Carlo (Bresme et al. Phys. Rev. E {\textbf 51} 289 (1995)) .
[ { "version": "v1", "created": "Fri, 20 Jul 2007 19:43:28 GMT" } ]
2007-07-23T00:00:00
[ [ "Blum", "L.", "" ], [ "Veloz", "D. V. Perez", "" ] ]
0707.3137
Philip Anderson
Philip A. Casey, J. D. Koralek, D.S. Dessau and Philip W. Anderson
Accurate theoretical fits to laser ARPES EDCs in the normal phase of cuprate superconductors
null
Nature Physics 4, 210-212 (2008)
10.1038/nphys833
null
cond-mat.str-el cond-mat.supr-con
null
Anderson has recently proposed a theory of the strange metal state above Tc in the high Tc superconductors. [arXiv:cond-mat/0512471] It is based on the idea that the unusual transport properties and spectral functions are caused by the strong Mott- Hubbard interactions and can be computed by using the formal apparatus of Gutzwiller projection. In ref. 1 Anderson computed only the tunneling spectrum and the power-law exponent of the infrared conductivity. He had calculated the energy distribution curves (EDCs) in angle resolved photoemission spectroscopy (ARPES) but was discouraged when these differed radically from the best ARPES measurements available at the time, and did not include them. In this letter we compare the spectral functions computed within this model to the novel laser-ARPES data of the Dessau group.These are found to capture the shape of the experimental EDCs with unprecedented accuracy and in principle have only one free parameter.
[ { "version": "v1", "created": "Fri, 20 Jul 2007 19:48:01 GMT" } ]
2015-05-13T00:00:00
[ [ "Casey", "Philip A.", "" ], [ "Koralek", "J. D.", "" ], [ "Dessau", "D. S.", "" ], [ "Anderson", "Philip W.", "" ] ]
0707.3138
Adam Van Tuyl
Elena Guardo and Adam Van Tuyl
ACM sets of points in multiprojective space
21 pages; revised final version; minor corrections; to appear in Collectanea Mathematica
null
null
null
math.AC math.AG
null
If X is a finite set of points in a multiprojective space P^n1 x ... x P^nr with r >= 2, then X may or may not be arithmetically Cohen-Macaulay (ACM). For sets of points in P^1 x P^1 there are several classifications of the ACM sets of points. In this paper we investigate the natural generalizations of these classifications to an arbitrary multiprojective space. We show that each classification for ACM points in P^1 x P^1 fails to extend to the general case. We also give some new necessary and sufficient conditions for a set of points to be ACM.
[ { "version": "v1", "created": "Fri, 20 Jul 2007 19:50:31 GMT" }, { "version": "v2", "created": "Wed, 28 Nov 2007 14:51:36 GMT" } ]
2007-11-28T00:00:00
[ [ "Guardo", "Elena", "" ], [ "Van Tuyl", "Adam", "" ] ]
0707.3139
Adam Van Tuyl
Elena Guardo and Adam Van Tuyl
Separators of points in a multiprojective space
13 pages; minor revisions; updated references; to appear in Manuscripta Mathematica
null
null
null
math.AC math.AG
null
In this note we develop some of the properties of separators of points in a multiprojective space. In particular, we prove multigraded analogs of results of Geramita, Maroscia, and Roberts relating the Hilbert function of X and X \{P} via the degree of a separator, and Abrescia, Bazzotti, and Marino relating the degree of a separator to shifts in the minimal multigraded free resolution of the ideal of points.
[ { "version": "v1", "created": "Fri, 20 Jul 2007 19:58:57 GMT" }, { "version": "v2", "created": "Fri, 4 Jan 2008 22:04:45 GMT" } ]
2011-11-10T00:00:00
[ [ "Guardo", "Elena", "" ], [ "Van Tuyl", "Adam", "" ] ]
0707.3140
Kenneth Guenter
Niels Strohmaier, Yosuke Takasu, Kenneth G\"unter, Robert J\"ordens, Michael K\"ohl, Henning Moritz and Tilman Esslinger
Interaction-controlled transport of an ultracold Fermi gas
4 pages, 4 Postscript figures
Phys. Rev. Lett. 99, 220601 (2007)
10.1103/PhysRevLett.99.220601
null
cond-mat.str-el quant-ph
null
We explore the transport properties of an interacting Fermi gas in a three-dimensional optical lattice. The center of mass dynamics of the atoms after a sudden displacement of the trap minimum is monitored for different interaction strengths and lattice fillings. With increasingly strong attractive interactions the weakly damped oscillation, observed for the non-interacting case, turns into a slow relaxational drift. Tuning the interaction strength during the evolution allows us to dynamically control the transport behavior. Strong attraction between the atoms leads to the formation of local pairs with a reduced tunneling rate. The interpretation in terms of pair formation is supported by a measurement of the number of doubly occupied lattice sites. This quantity also allows us to determine the temperature of the non-interacting gas in the lattice to be as low as (27\pm2)% of the Fermi temperature.
[ { "version": "v1", "created": "Fri, 20 Jul 2007 20:14:14 GMT" }, { "version": "v2", "created": "Wed, 5 Dec 2007 13:33:24 GMT" } ]
2007-12-05T00:00:00
[ [ "Strohmaier", "Niels", "" ], [ "Takasu", "Yosuke", "" ], [ "Günter", "Kenneth", "" ], [ "Jördens", "Robert", "" ], [ "Köhl", "Michael", "" ], [ "Moritz", "Henning", "" ], [ "Esslinger", "Tilman", "" ] ]
0707.3141
Desika Narayanan
Desika Narayanan (1), Yuexing Li (2), Thomas J. Cox (2), Lars Hernquist (2), Philip Hopkins (2), Sukanya Chakrabarti (2), Romeel Dave (1), Tiziana Di Matteo (3), Liang Gao (4), Craig Kulesa (1), Brant Robertson (5), Christopher Walker (1) ((1) Arizona, (2) CfA, (3) Carnegie Mellon, (4), ICC Durham, (5), KICP Chicago)
The Nature of CO Emission From z~6 Quasars
18 Pages, 14 Figures, Accepted by ApJ
null
10.1086/521776
null
astro-ph
null
We investigate the nature of CO emission from z~6 quasars by combining non-LTE radiative transfer calculations with merger-driven models of z~6 quasar formation that arise naturally in LCDM cosmological simulations. We consider four model quasars formed in 10^12-10^13 M_sun halos from different merging histories. Our main results follow. Owing to massive starbursts and funneling of dense gas into the nuclear regions of merging galaxies, the CO is highly excited and the flux density peaks between J=5-8. The CO morphology of z~6 quasars often exhibits multiple emission peaks which arise from H2 concentrations which have not yet fully coalesced. Quasars at z~6 display a large range of sightline dependent line widths such that the lines are narrowest when the rotating H2 gas associated with the quasar is viewed face-on (when L_B is largest), and broadest when the gas is seen edge-on (when L_B is lowest). Thus for all models selection effects exist such that quasars selected for optical luminosity are preferentially face-on which may result in detected CO line widths narrower than the median. The sightline averaged line width is reflective of the circular velocity (V_c) of the host halo, and ranges from sigma~300-650 km/s. For optically selected QSOs, 10-25% (halo-mass dependant) of sightlines have narrow line widths compatible with the sole CO detection at z>6, J1148+5251. When accounting for both the temporal evolution of CO line widths, as well as the redshift evolution of halo V_c, these models self-consistently account for the CO line widths of both z~2 sub-mm galaxies and QSO's. Finally, the dynamical mass derived from the sightline averaged line widths provides a good estimate of the total mass, and allows for a stellar bulge and SMBH consistent with the local M_BH-M_bulge relation. [abridged]
[ { "version": "v1", "created": "Fri, 20 Jul 2007 20:03:38 GMT" } ]
2009-11-13T00:00:00
[ [ "Narayanan", "Desika", "" ], [ "Li", "Yuexing", "" ], [ "Cox", "Thomas J.", "" ], [ "Hernquist", "Lars", "" ], [ "Hopkins", "Philip", "" ], [ "Chakrabarti", "Sukanya", "" ], [ "Dave", "Romeel", "" ], [ "Di Matteo", "Tiziana", "" ], [ "Gao", "Liang", "" ], [ "Kulesa", "Craig", "" ], [ "Robertson", "Brant", "" ], [ "Walker", "Christopher", "" ] ]
0707.3142
David R. Ballantyne
D.R. Ballantyne (Dept. of Physics, Univ. of Arizona)
The Accretion Geometry in Radio-Loud Active Galaxies
15 pages, invited review, accepted by Modern Physics Letters A
Mod.Phys.Lett.A22:2397-2411,2007
10.1142/S0217732307024322
null
astro-ph
null
We review the latest attempts to determine the accretion geometry in radio-loud active galactic nuclei (AGN). These objects, which comprise ~10-20% of the AGN population, produce powerful collimated radio jets that can extend thousands of parsecs from the center of the host galaxy. Recent multiwavelength surveys have shown that radio-loudness is more common in low-luminosity AGN than in higher luminosity Seyfert galaxies or quasars. These low-luminosity AGN have small enough accretion rates that they are most likely accreting via a geometrically thick and radiatively inefficient accretion flow. In contrast, X-ray spectroscopic observations of three higher luminosity broad-line radio galaxies (3C 120, 4C+74.26 and PG 1425+267) have found evidence for an untruncated thin disk extending very close to the black hole. These tentative detections indicate that, for this class of radio-loud AGN, the accretion geometry is very similar to their radio-quiet counterparts. These observations suggest that there are three conditions to jet formation that must be satisfied: the presence of a rapidly spinning black hole, an accretion flow with a large H/r ratio, and a favorable magnetic field geometry.
[ { "version": "v1", "created": "Fri, 20 Jul 2007 20:07:42 GMT" } ]
2008-11-26T00:00:00
[ [ "Ballantyne", "D. R.", "", "Dept. of Physics, Univ. of Arizona" ] ]
0707.3143
Kerry Soileau
Kerry M. Soileau
A parameterization of the Fermat curves satisfying x^(2N)+y^(2N)=1
Corrected a typo
null
null
null
math.GM
null
Note that the family of closed curves C_N={(x,y)\in R^2;x^(2N)+y^(2N)=1} for N=1,2,3,... approaches the boundary of [-1,1]^2 as N \to \infty. In this paper we exhibit a natural parameterization of these curves and generalize to a larger class of equations.
[ { "version": "v1", "created": "Fri, 20 Jul 2007 20:08:34 GMT" }, { "version": "v2", "created": "Sun, 29 Jul 2007 05:31:48 GMT" } ]
2007-07-29T00:00:00
[ [ "Soileau", "Kerry M.", "" ] ]
0707.3144
Deokkeun An
Deokkeun An, Donald M. Terndrup, and Marc H. Pinsonneault (The Ohio State University)
The Distances to Open Clusters from Main-Sequence Fitting. IV. Galactic Cepheids, the LMC, and the Local Distance Scale
28 pages, 21 figures; accepted for publication in the ApJ
Astrophys.J.671:1640-1668,2007
10.1086/522304
null
astro-ph
null
We derive the basic properties of seven Galactic open clusters containing Cepheids and construct their period-luminosity (P-L) relations. For our cluster main-sequence fitting we extend previous Hyades-based empirical color-temperature corrections to hotter stars using the Pleiades as a template. We use BVI_{C}JHK_{s} data to test the reddening law, and include metallicity effects to perform a more comprehensive study for our clusters than prior efforts. The ratio of total to selective extinction R_V that we derive is consistent with expectations. Assuming the LMC P-L slopes, we find <M_V> = -3.93 +/- 0.07 (statistical) +/- 0.14 (systematic) for 10-day period Cepheids, which is generally fainter than those in previous studies. Our results are consistent with recent HST and Hipparcos parallax studies when using the Wesenheit magnitudes W(VI). Uncertainties in reddening and metallicity are the major remaining sources of error in the V-band P-L relation, but a higher precision could be obtained with deeper optical and near-infrared cluster photometry. We derive distances to NGC4258, the LMC, and M33 of (m - M)_0 = 29.28 +/- 0.10, 18.34 +/- 0.06, and 24.55 +/- 0.28, respectively, with an additional systematic error of 0.16 mag in the P-L relations. The distance to NGC4258 is in good agreement with the geometric distance derived from water masers [\Delta (m - M)_0 = 0.01 +/- 0.24]; our value for M33 is less consistent with the distance from an eclipsing binary [\Delta (m - M)_0 = 0.37 +/- 0.34]; our LMC distance is moderately shorter than the adopted distance in the HST Key Project, which formally implies an increase in the Hubble constant of 7% +/- 8%.
[ { "version": "v1", "created": "Sun, 22 Jul 2007 23:08:47 GMT" }, { "version": "v2", "created": "Mon, 26 Nov 2007 16:41:27 GMT" } ]
2009-08-21T00:00:00
[ [ "An", "Deokkeun", "", "The Ohio\n State University" ], [ "Terndrup", "Donald M.", "", "The Ohio\n State University" ], [ "Pinsonneault", "Marc H.", "", "The Ohio\n State University" ] ]
0707.3145
Daniel Phillips
Prashanth Jaikumar, Daniel R. Phillips, Lucas Platter, Madappa Prakash
Muon production in low-energy electron-nucleon and electron-nucleus scattering
24 pages. Additional figure showing energy-dependence of total cross section, minor changes to text. Conclusions unaltered. This version to appear in Physical Review D
Phys.Rev.D76:115001,2007
10.1103/PhysRevD.76.115001
null
hep-ph nucl-ex nucl-th
null
Recently, muon production in electron-proton scattering has been suggested as a possible candidate reaction for the identification of lepton-flavor violation due to physics beyond the Standard Model. Here we point out that the Standard-Model processes $e^- p \to \mu^- p \bar{\nu}_\mu \nu_e$ and $e^- p \to e^- n \mu^+ \nu_\mu$ can cloud potential beyond-the-Standard-Model signals in electron-proton collisions. We find that Standard-Model $e p \to \mu X$ cross sections exceed those from lepton-flavor-violating operators by several orders of magnitude. We also discuss the possibility of using a nuclear target to enhance the $e p \to \mu X$ signal.
[ { "version": "v1", "created": "Fri, 20 Jul 2007 20:14:38 GMT" }, { "version": "v2", "created": "Fri, 30 Nov 2007 19:44:33 GMT" } ]
2008-11-26T00:00:00
[ [ "Jaikumar", "Prashanth", "" ], [ "Phillips", "Daniel R.", "" ], [ "Platter", "Lucas", "" ], [ "Prakash", "Madappa", "" ] ]
0707.3146
Smadar Naoz
Smadar Naoz (1), Rennan Barkana (1) ((1) Tel Aviv University)
Detecting Early Galaxies Through Their 21-cm Signature
5 pages, 3 figures, submitted to MNRAS Lett
null
10.1111/j.1745-3933.2008.00434.x
null
astro-ph
null
New observations over the next few years of the emission of distant objects will help unfold the chapter in cosmic history around the era of the first galaxies. These observations will use the neutral hydrogen emission or absorption at a wavelength of 21-cm as a detector of the hydrogen abundance. We predict the signature on the 21-cm signal of the early generations of galaxies. We calculate the 21-cm power spectrum including two physical effects that were neglected in previous calculations. The first is the redistribution of the UV photons from the first galaxies due to their scattering off of the neutral hydrogen, which results in an enhancement of the 21-cm signal. The second is the presence of an ionized hydrogen bubble near each source, which produces a cutoff at observable scales. We show that the resulting clear signature in the 21-cm power spectrum can be used to detect and study the population of galaxies that formed just 200 million years after the Big Bang.
[ { "version": "v1", "created": "Fri, 20 Jul 2007 20:26:15 GMT" }, { "version": "v2", "created": "Wed, 10 Oct 2007 12:49:24 GMT" } ]
2009-11-13T00:00:00
[ [ "Naoz", "Smadar", "", "Tel Aviv University" ], [ "Barkana", "Rennan", "", "Tel Aviv University" ] ]
0707.3147
Gregory G. Howes
Gregory G. Howes, Steven C. Cowley, William Dorland, Gregory W. Hammett, Eliot Quataert, and Alexander A. Schekochihin
A Model of Turbulence in Magnetized Plasmas: Implications for the Dissipation Range in the Solar Wind
29 pages, 14 figures
J. Geophys. Res. 113, A05103 (2008)
10.1029/2007JA012665
null
astro-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This paper studies the turbulent cascade of magnetic energy in weakly collisional magnetized plasmas. A cascade model is presented, based on the assumptions of local nonlinear energy transfer in wavenumber space, critical balance between linear propagation and nonlinear interaction times, and the applicability of linear dissipation rates for the nonlinearly turbulent plasma. The model follows the nonlinear cascade of energy from the driving scale in the MHD regime, through the transition at the ion Larmor radius into the kinetic Alfven wave regime, in which the turbulence is dissipated by kinetic processes. The turbulent fluctuations remain at frequencies below the ion cyclotron frequency due to the strong anisotropy of the turbulent fluctuations, k_parallel << k_perp (implied by critical balance). In this limit, the turbulence is optimally described by gyrokinetics; it is shown that the gyrokinetic approximation is well satisfied for typical slow solar wind parameters. Wave phase velocity measurements are consistent with a kinetic Alfven wave cascade and not the onset of ion cyclotron damping. The conditions under which the gyrokinetic cascade reaches the ion cyclotron frequency are established. Cascade model solutions imply that collisionless damping provides a natural explanation for the observed range of spectral indices in the dissipation range of the solar wind. The dissipation range spectrum is predicted to be an exponential fall off; the power-law behavior apparent in observations may be an artifact of limited instrumental sensitivity. The cascade model is motivated by a programme of gyrokinetic simulations of turbulence and particle heating in the solar wind.
[ { "version": "v1", "created": "Fri, 20 Jul 2007 20:36:49 GMT" }, { "version": "v2", "created": "Fri, 12 Dec 2008 22:10:53 GMT" } ]
2015-05-13T00:00:00
[ [ "Howes", "Gregory G.", "" ], [ "Cowley", "Steven C.", "" ], [ "Dorland", "William", "" ], [ "Hammett", "Gregory W.", "" ], [ "Quataert", "Eliot", "" ], [ "Schekochihin", "Alexander A.", "" ] ]
0707.3148
James M. Overduin
J.M. Overduin, P.S. Wesson and B. Mashhoon
Decaying Dark Energy in Higher-Dimensional Gravity
11 pages, 5 figures, submitted to A&A
Astronomy & Astrophysics 473 (2007) 727-731
10.1051/0004-6361:20077670
null
astro-ph
null
We use data from observational cosmology to put constraints on higher-dimensional extensions of general relativity in which the effective four-dimensional dark-energy density (or cosmological "constant") decays with time. In particular we study the implications of this decaying dark energy for the age of the universe, large-scale structure formation, big-bang nucleosynthesis and the magnitude-redshift relation for Type Ia supernovae. Two of these tests (age and the magnitude-redshift relation) place modest lower limits on the free parameter of the theory, a cosmological length scale L akin to the de Sitter radius. These limits will improve if experimental uncertainties on supernova magnitudes can be reduced around z=1.
[ { "version": "v1", "created": "Fri, 20 Jul 2007 20:42:09 GMT" } ]
2009-11-13T00:00:00
[ [ "Overduin", "J. M.", "" ], [ "Wesson", "P. S.", "" ], [ "Mashhoon", "B.", "" ] ]
0707.3149
Gregory G. Howes
Gregory G. Howes, Steven C. Cowley, William Dorland, Gregory W. Hammett, Eliot Quataert, and Alexander A. Schekochihin
Dissipation-Scale Turbulence in the Solar Wind
6 pages, 2 figures, accepted for publication in AIP Conference Proceedings on "Turbulence and Nonlinear Processes in Astrophysical Plasmas"
AIPConf.Proc.932:3-8,2007
10.1063/1.2778938
null
astro-ph
null
We present a cascade model for turbulence in weakly collisional plasmas that follows the nonlinear cascade of energy from the large scales of driving in the MHD regime to the small scales of the kinetic Alfven wave regime where the turbulence is dissipated by kinetic processes. Steady-state solutions of the model for the slow solar wind yield three conclusions: (1) beyond the observed break in the magnetic energy spectrum, one expects an exponential cut-off; (2) the widely held interpretation that this dissipation range obeys power-law behavior is an artifact of instrumental sensitivity limitations; and, (3) over the range of parameters relevant to the solar wind, the observed variation of dissipation range spectral indices from -2 to -4 is naturally explained by the varying effectiveness of Landau damping, from an undamped prediction of -7/3 to a strongly damped index around -4.
[ { "version": "v1", "created": "Fri, 20 Jul 2007 20:52:16 GMT" } ]
2008-11-26T00:00:00
[ [ "Howes", "Gregory G.", "" ], [ "Cowley", "Steven C.", "" ], [ "Dorland", "William", "" ], [ "Hammett", "Gregory W.", "" ], [ "Quataert", "Eliot", "" ], [ "Schekochihin", "Alexander A.", "" ] ]
0707.3150
Jianwei Qiu
Edmond L. Berger (ANL), Jian-Wei Qiu (Iowa State/ANL), Ricardo A. Rodriguez-Pedraza (Iowa State)
Angular distribution of leptons from the decay of massive vector bosons
4 pages; a few changes in wording; one reference added. Version in press at Phys. Lett. B
Phys.Lett.B656:74-78,2007
10.1016/j.physletb.2007.09.008
ANL-HEP-PR-07-52
hep-ph nucl-th
null
We examine the transverse momentum $Q_\perp$ dependence of the helicity structure functions for massive vector bosons of mass $Q$ in hadron reactions. We demonstrate that large logarithmic terms of the form $\ln(Q/Q_\perp)$ in the helicity structure functions have the same origin as the logarithmic terms in the angular-integrated cross section and that they can be resummed to all orders in the strong coupling $\alpha_s$, in the same way as the angular-integrated cross section. As a consequence of current conservation, the resummed part of the helicity structure functions preserves the Lam-Tung relation as a function of $Q_\perp$ to all orders in $\alpha_s$.
[ { "version": "v1", "created": "Fri, 20 Jul 2007 21:00:41 GMT" }, { "version": "v2", "created": "Sun, 23 Sep 2007 15:55:17 GMT" } ]
2008-11-26T00:00:00
[ [ "Berger", "Edmond L.", "", "ANL" ], [ "Qiu", "Jian-Wei", "", "Iowa State/ANL" ], [ "Rodriguez-Pedraza", "Ricardo A.", "", "Iowa State" ] ]
0707.3151
David Wright
Joost Berson, Arno van den Essen, and David Wright
Stable Tameness of Two-Dimensional Polynomial Automorphisms Over a Regular Ring
18 pages
null
null
null
math.AC math.AG
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper it is established that all two-dimensional polynomial automorphisms over a regular ring R are stably tame. In the case R is a Dedekind Q-algebra, some stronger results are obtained. A key element in the proof is a theorem which yields the following corollary: Over an Artinian ring A all two-dimensional polynomial automorphisms having Jacobian determinant one are stably tame, and are tame if A is a Q-algebra. Another crucial ingredient, of interest in itself, is that stable tameness is a local property: If an automorphism is locally tame, then it is stably tame.
[ { "version": "v1", "created": "Mon, 23 Jul 2007 17:42:17 GMT" }, { "version": "v10", "created": "Thu, 19 Apr 2012 19:15:57 GMT" }, { "version": "v2", "created": "Tue, 24 Jul 2007 19:48:28 GMT" }, { "version": "v3", "created": "Mon, 6 Aug 2007 18:43:40 GMT" }, { "version": "v4", "created": "Tue, 4 Mar 2008 23:17:10 GMT" }, { "version": "v5", "created": "Tue, 8 Apr 2008 20:21:37 GMT" }, { "version": "v6", "created": "Thu, 9 Oct 2008 20:39:54 GMT" }, { "version": "v7", "created": "Mon, 20 Oct 2008 18:53:37 GMT" }, { "version": "v8", "created": "Tue, 30 Dec 2008 21:40:23 GMT" }, { "version": "v9", "created": "Thu, 10 Jun 2010 20:02:54 GMT" } ]
2012-04-20T00:00:00
[ [ "Berson", "Joost", "" ], [ "Essen", "Arno van den", "" ], [ "Wright", "David", "" ] ]
0707.3152
Michael Trott
Sonny Mantry, Michael J. Ramsey-Musolf, Michael Trott
New Physics Effects in Higgs Decay to Tau Leptons
10 pages, 6 figures, V2: typos corrected
Phys.Lett.B660:54-61,2008
10.1016/j.physletb.2007.12.021
null
hep-ph
null
We study the possible effects of TeV scale new physics (NP) on the rate for Higgs boson decays to charged leptons, focusing on the tau tau channel which can be readily studied at the Large Hadron collider. Using an SU(3)_C X SU(2)_L X U(1)_Y invariant effective theory valid below a NP scale Lambda, we determine all effective operators up to dimension six that could generate appreciable contributions to the decay rate and compute the dependence of the rate on the corresponding operator coefficients. We bound the size of these operator coefficients based on the scale of the tau mass, naturalness considerations, and experimental constraints on the tau anomalous magnetic moment. These considerations imply that contributions to the decay rate from a NP scale Lambda ~ TeV could be comparable to the prediction based on the SM Yukawa interaction. A reliable test of the Higgs mechanism for fermion mass generation via the h-> tau tau channel is possible only after such NP effects are understood and brought under theoretical control.
[ { "version": "v1", "created": "Fri, 20 Jul 2007 21:01:54 GMT" }, { "version": "v2", "created": "Mon, 10 Sep 2007 23:49:54 GMT" } ]
2008-11-26T00:00:00
[ [ "Mantry", "Sonny", "" ], [ "Ramsey-Musolf", "Michael J.", "" ], [ "Trott", "Michael", "" ] ]
0707.3153
Evaldo M. F. Curado
Veit Schwammle, Fernando D. Nobre and Evaldo M. F. Curado
Consequences of the H-Theorem from Nonlinear Fokker-Planck Equations
19 pages, no figures
null
10.1103/PhysRevE.76.041123
null
cond-mat.stat-mech
null
A general type of nonlinear Fokker-Planck equation is derived directly from a master equation, by introducing generalized transition rates. The H-theorem is demonstrated for systems that follow those classes of nonlinear Fokker-Planck equations, in the presence of an external potential. For that, a relation involving terms of Fokker-Planck equations and general entropic forms is proposed. It is shown that, at equilibrium, this relation is equivalent to the maximum-entropy principle. Families of Fokker-Planck equations may be related to a single type of entropy, and so, the correspondence between well-known entropic forms and their associated Fokker-Planck equations is explored. It is shown that the Boltzmann-Gibbs entropy, apart from its connection with the standard -- linear Fokker-Planck equation -- may be also related to a family of nonlinear Fokker-Planck equations.
[ { "version": "v1", "created": "Fri, 20 Jul 2007 21:41:27 GMT" } ]
2009-11-13T00:00:00
[ [ "Schwammle", "Veit", "" ], [ "Nobre", "Fernando D.", "" ], [ "Curado", "Evaldo M. F.", "" ] ]
0707.3154
David M. Smith
David M. Smith, David M. Dawson and Jean H. Swank
Hysteresis of spectral evolution in the soft state of black-hole binary LMC X-3
14 pages, 6 figures, accepted by The Astrophysical Journal
null
10.1086/521822
null
astro-ph
null
We report the discovery of hysteresis between the x-ray spectrum and luminosity of black-hole binary LMC X-3. Our observations, with the Proportional Counter Array on the Rossi X-ray Timing Explorer, took place entirely within the soft spectral state, dominated by a spectral component that was fitted well with a multicolor disk blackbody. A power-law component was seen only during times when the luminosity of the disk blackbody was declining. The x-ray luminosity at these times was comparable to that seen in transient systems (x-ray novae) when they return to the hard state at the end of an outburst. Our observations may represent partial transitions to the hard state; complete transitions have been seen in this system by Wilms et al. (2001). If they are related to the soft-to-hard transition in transients, then they demonstrate that hysteresis effects can appear without a full state transition. We discuss these observations in the context of earlier observations of hysteresis within the hard state of binaries 1E 1740.7-2942 and GRS 1758-258 and in relation to published explanations of hysteresis in transients.
[ { "version": "v1", "created": "Fri, 20 Jul 2007 21:30:52 GMT" } ]
2009-11-13T00:00:00
[ [ "Smith", "David M.", "" ], [ "Dawson", "David M.", "" ], [ "Swank", "Jean H.", "" ] ]
0707.3155
Sergey V. Lototsky
S. V. Lototsky
A Random Change of Variables and Applications to the Stochastic Porous Medium Equation with Multiplicative Time Noise
null
null
null
null
math.PR math.AP
null
A change of variables is introduced to reduce certain nonlinear stochastic evolution equations with multiplicative noise to the corresponding deterministic equation. The result is then used to investigate a stochastic porous medium equation.
[ { "version": "v1", "created": "Fri, 20 Jul 2007 21:47:55 GMT" } ]
2007-07-24T00:00:00
[ [ "Lototsky", "S. V.", "" ] ]
0707.3156
Adam Szczepaniak
Peng Guo, Adam P. Szczepaniak, Giuseppe Galata, Andrea Vassallo, Elena Santopinto
Gluelump spectrum from Coulomb gauge QCD
8 pages, 5 figures
Phys.Rev.D77:056005,2008
10.1103/PhysRevD.77.056005
null
hep-ph
null
We compute the energy spectrum of gluelumps defined as gluonic excitations bound to a localized, static octet source. We are able to reproduce the nontrivial ordering of the spin-parity levels and show how this is related to the non-abelian part of the Coulomb interaction between color charges.
[ { "version": "v1", "created": "Fri, 20 Jul 2007 21:49:05 GMT" } ]
2008-11-26T00:00:00
[ [ "Guo", "Peng", "" ], [ "Szczepaniak", "Adam P.", "" ], [ "Galata", "Giuseppe", "" ], [ "Vassallo", "Andrea", "" ], [ "Santopinto", "Elena", "" ] ]
0707.3157
Anh-Thu Le
Toru Morishita, Anh-Thu Le, Zhangjin Chen, and C. D. Lin
Accurate retrieval of structural information from laser-induced photoelectron and high-harmonic spectra by few-cycle laser pulses
4 pages, 4 figures
Phys. Rev. Lett. 100, 013903 (2008)
10.1103/PhysRevLett.100.013903
null
physics.atom-ph
null
By analyzing ``exact'' theoretical results from solving the time-dependent Schr\"odinger equation of atoms in few-cycle laser pulses, we established the general conclusion that differential elastic scattering and photo-recombination cross sections of the target ion with {\em free} electrons can be extracted accurately from laser-generated high-energy electron momentum spectra and high-order harmonic spectra, respectively. Since both electron scattering and photoionization (the inverse of photo-recombination) are the conventional means for interrogating the structure of atoms and molecules, this result shows that existing few-cycle infrared lasers can be implemented for ultrafast imaging of transient molecules with temporal resolution of a few femtoseconds.
[ { "version": "v1", "created": "Fri, 20 Jul 2007 21:52:32 GMT" } ]
2008-04-04T00:00:00
[ [ "Morishita", "Toru", "" ], [ "Le", "Anh-Thu", "" ], [ "Chen", "Zhangjin", "" ], [ "Lin", "C. D.", "" ] ]
0707.3158
Michael R. Norman
I. Paul, A. D. Klironomos, M. R. Norman
Quasiparticle mirages in the tunneling spectra of d-wave superconductors
revised text with new figures, to be published, Phys Rev B
Phys. Rev. B 78, 020508(R) (2008)
10.1103/PhysRevB.78.020508
null
cond-mat.supr-con cond-mat.str-el
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We illustrate the importance of many-body effects in the Fourier transformed local density of states (FT-LDOS) of d-wave superconductors from a model of electrons coupled to an Einstein mode with energy Omega_0. For bias energies significantly larger than Omega_0 the quasiparticles have short lifetimes due to this coupling, and the FT-LDOS is featureless if the electron-impurity scattering is treated within the Born approximation. In this regime it is important to include boson exchange for the electron-impurity scattering which provides a `step down' in energy for the electrons and allows for long lifetimes. This many-body effect produces qualitatively different results, namely the presence of peaks in the FT-LDOS which are mirrors of the quasiparticle interference peaks which occur at bias energies smaller than ~ Omega_0. The experimental observation of these quasiparticle mirages would be an important step forward in elucidating the role of many-body effects in FT-LDOS measurements.
[ { "version": "v1", "created": "Fri, 20 Jul 2007 22:02:10 GMT" }, { "version": "v2", "created": "Thu, 17 Jul 2008 02:42:10 GMT" } ]
2009-11-13T00:00:00
[ [ "Paul", "I.", "" ], [ "Klironomos", "A. D.", "" ], [ "Norman", "M. R.", "" ] ]
0707.3159
Mikhail L. Polianski
M. L. Polianski and M. Buttiker
Rectification and nonlinear transport in chaotic dots and rings
16 pages, 7 figures; v2--published verison
Phys. Rev. B 76, 205308 (2007)
10.1103/PhysRevB.76.205308
null
cond-mat.mes-hall cond-mat.mtrl-sci
null
We investigate the nonlinear current-voltage characteristic of mesoscopic conductors and the current generated through rectification of an alternating external bias. To leading order in applied voltages both the nonlinear and the rectified current are quadratic. This current response can be described in terms of second order conductance coefficients and for a generic mesoscopic conductor they fluctuate randomly from sample to sample. Due to Coulomb interactions the symmetry of transport under magnetic field inversion is broken in a two-terminal setup. Therefore, we consider both the symmetric and antisymmetric nonlinear conductances separately. We treat interactions self-consistently taking into account nearby gates. The nonlinear current is determined by different combinations of second order conductances depending on the way external voltages are varied away from an equilibrium reference point (bias mode). We discuss the role of the bias mode and circuit asymmetry in recent experiments. In a photovoltaic experiment the alternating perturbations are rectified, and the fluctuations of the nonlinear conductance are shown to decrease with frequency. Their asymptotical behavior strongly depends on the bias mode and in general the antisymmetric conductance is suppressed stronger then the symmetric conductance. We next investigate nonlinear transport and rectification in chaotic rings. To this extent we develop a model which combines a chaotic quantum dot and a ballistic arm to enclose an Aharonov-Bohm flux. In the linear two-probe conductance the phase of the Aharonov-Bohm oscillation is pinned while in nonlinear transport phase rigidity is lost. We discuss the shape of the mesoscopic distribution of the phase and determine the phase fluctuations.
[ { "version": "v1", "created": "Mon, 23 Jul 2007 12:26:09 GMT" }, { "version": "v2", "created": "Thu, 8 Nov 2007 11:32:16 GMT" } ]
2007-11-08T00:00:00
[ [ "Polianski", "M. L.", "" ], [ "Buttiker", "M.", "" ] ]
0707.3160
Leonid Bogachev
L. V. Bogachev
Random Walks in Random Environments
A review article in the Encyclopedia of Mathematical Physics (Elsevier, 2006). http://www.elsevier.com/wps/find/bookdescription.cws_home/705128/description
Encyclopedia of Mathematical Physics (J.-P. Francoise, G. Naber, and S.T. Tsou, eds.), Vol. 4, pp. 353-371. Elsevier, Oxford, 2006
10.1016/B0-12-512666-2/00063-8
null
math.PR math-ph math.MP
null
Random walks provide a simple conventional model to describe various transport processes, for example propagation of heat or diffusion of matter through a medium. However, in many practical cases the medium is highly irregular due to defects, impurities, fluctuations etc., and it is natural to model this as random environment. In the random walks context, such models are referred to as Random Walks in Random Environments (RWRE). This is a relatively new chapter in applied probability and physics of disordered systems, initiated in the 1970s. Early interest was motivated by some problems in biology, crystallography and metal physics, but later applications have spread through numerous areas. After 30 years of extensive work, RWRE remain a very active area of research, which has already led to many surprising discoveries. The goal of this article is to give a brief introduction to the beautiful area of RWRE. The principal model to be discussed is a random walk with nearest-neighbor jumps in independent identically distributed (i.i.d.) random environment in one dimension, although we shall also comment on some extensions and generalizations. The focus is on rigorous results; however, heuristics is used freely to motivate the ideas and explain the approaches and proofs. In a few cases, sketches of the proofs have been included, which should help the reader to appreciate the flavor of results and methods.
[ { "version": "v1", "created": "Fri, 20 Jul 2007 22:32:43 GMT" } ]
2019-06-10T00:00:00
[ [ "Bogachev", "L. V.", "" ] ]
0707.3161
Masami Ouchi
Masami Ouchi, Kazuhiro Shimasaku, Masayuki Akiyama, Chris Simpson, Tomoki Saito, Yoshihiro Ueda, Hisanori Furusawa, Kazuhiro Sekiguchi, Toru Yamada, Tadayuki Kodama, Nobunari Kashikawa, Sadanori Okamura, Masanori Iye, Tadafumi Takata, Michitoshi Yoshida, Makiko Yoshida
The Subaru/XMM-Newton Deep Survey (SXDS). IV. Evolution of Lya Emitters from z=3.1 to 5.7 in the 1 deg^2 Field: Luminosity Functions and AGN
75 pages, 27 figures; ApJS in press. High resolution version at http://www.ociw.edu/~ouchi/work/astroph/sxds_LAEs/ouchi_SXDSLAE_ApJS.pdf
null
10.1086/527673
null
astro-ph
null
We present luminosity functions (LFs) and various properties of Lya emitters (LAEs) at z=3.1, 3.7, and 5.7, in a 1 deg^2 sky of the Subaru/XMM-Newton Deep Survey (SXDS) Field. We obtain a photometric sample of 858 LAE candidates based on deep Subaru/Suprime-Cam imaging data, and a spectroscopic sample of 84 confirmed LAEs from Subaru/FOCAS and VLT/VIMOS spectroscopy in a survey volume of ~10^6 Mpc^3 with a limiting Lya luminosity of ~3x10^42 erg/s. We derive the LFs of Lya and UV-continuum (~1500 \AA) for each redshift, taking into account the statistical error and the field-to-field variation. We find that the apparent Lya LF shows no significant evolution between z=3.1 and 5.7 within factors of 1.8 and 2.7 in L* and phi*, respectively. On the other hand, the UV LF of LAEs increases from z=3.1 to 5.7, indicating that galaxies with Lya emission are more common at earlier epochs. We identify six LAEs with AGN activities from our spectra combined with VLA, Spitzer, and XMM-Newton data. Among the photometrically selected LAEs at z=3.1 and 3.7, only ~1 % show AGN activities, while the brightest LAEs with logL(Lya) >~ 43.4-43.6 erg/s appear to always host AGNs. Our LAEs are bluer in UV-continuum color than dropout galaxies, suggesting lower extinction and/or younger stellar populations. Our stacking analyses provide upper limits to the radio luminosity and the f(HeII)/f(Lya) line fraction, and constrain the hidden star formation (+low-luminosity AGN) and the primordial population in LAEs.
[ { "version": "v1", "created": "Fri, 20 Jul 2007 22:34:14 GMT" }, { "version": "v2", "created": "Wed, 19 Dec 2007 05:15:28 GMT" }, { "version": "v3", "created": "Mon, 2 Jun 2008 19:49:48 GMT" } ]
2008-06-02T00:00:00
[ [ "Ouchi", "Masami", "" ], [ "Shimasaku", "Kazuhiro", "" ], [ "Akiyama", "Masayuki", "" ], [ "Simpson", "Chris", "" ], [ "Saito", "Tomoki", "" ], [ "Ueda", "Yoshihiro", "" ], [ "Furusawa", "Hisanori", "" ], [ "Sekiguchi", "Kazuhiro", "" ], [ "Yamada", "Toru", "" ], [ "Kodama", "Tadayuki", "" ], [ "Kashikawa", "Nobunari", "" ], [ "Okamura", "Sadanori", "" ], [ "Iye", "Masanori", "" ], [ "Takata", "Tadafumi", "" ], [ "Yoshida", "Michitoshi", "" ], [ "Yoshida", "Makiko", "" ] ]
0707.3162
Joan Sola
Giancarlo Ferrera, Jaume Guasch, David Lopez-Val, Joan Sola
Triple Higgs boson production in the Linear Collider
LaTeX, 17 pages, 4 figures, 5 tables. References and comments added. Version accepted in Phys. Lett. B
Phys.Lett.B659:297-307,2008
10.1016/j.physletb.2007.10.072
UB-ECM-PF-07/22
hep-ph
null
Triple Higgs boson production (3H) may provide essential information to reconstruct the Higgs potential. We consider 3H-production in the International Linear Collider (ILC) both in the Minimal Supersymmetric Standard Model (MSSM) and in the general Two-Higgs-doublet Model (2HDM). We compute the total cross-section for the various 3H final states, such as H^+ H^- h^0, H^0 A^0 h^0, etc. and compare with the more traditional double Higgs (2H) boson production processes. While the cross-sections for the 2H final states lie within the same order of magnitude in both the MSSM and 2HDM, we find that for the 3H states the maximum 2HDM cross-sections, being of order 0.1 pb, are much larger than the MSSM ones which in most cases are of order 10^{-6} pb or less. Actually, the 3H processes could be the dominant mechanism for Higgs boson production in the 2HDM. Ultimately the origin of the remarkable enhancement of the 3H channels in the 2HDM case (for both type I and type II models) originates in the structure of the trilinear Higgs boson couplings. The extremely clean environment of the ILC should allow a relatively comfortable tagging of the three Higgs boson events. In view of the fact that the MSSM contribution is negligible, these events should manifest themselves mainly in the form of 6 heavy-quark jet final states. Some of these signatures could be spectacular, and in case of being detected would constitute strong evidence of an extended Higgs sector of non-supersymmetric origin.
[ { "version": "v1", "created": "Fri, 20 Jul 2007 23:08:01 GMT" }, { "version": "v2", "created": "Tue, 23 Oct 2007 10:48:10 GMT" } ]
2008-11-26T00:00:00
[ [ "Ferrera", "Giancarlo", "" ], [ "Guasch", "Jaume", "" ], [ "Lopez-Val", "David", "" ], [ "Sola", "Joan", "" ] ]
0707.3163
Michael Kozdron
Tom Alberts (New York University), Michael J. Kozdron (University of Regina)
Intersection probabilities for a chordal SLE path and a semicircle
v2: 11 pages, 7 figures; changed title, fixed typos, shortened some proofs, updated acknowledgements and references
Electron. Comm. Probab., volume 13, paper 43, pages 448-460, 2008
null
null
math.PR
null
We derive a number of estimates for the probability that a chordal SLE path in the upper half plane H intersects a semicircle centred on the real line. We prove that if 0<kappa<8 and gamma:[0,infinity) to closure(H) is a chordal SLE in H from 0 to infinity, then P(gamma[0,infinity) cap C(x;rx) neq emptyset) asymp r^(4a-1) where a=2/kappa and C(x;rx) denotes the semicircle centred at x>0 of radius rx, 0<r<1/3, in the upper half plane. As an application of our results, for 0<kappa<8, we derive an estimate for the diameter of a chordal SLE path in H between two real boundary points 0 and x>0. For 4<kappa<8, we also estimate the probability that an entire semicircle on the real line is swallowed at once by a chordal SLE path in H from 0 to infinity.
[ { "version": "v1", "created": "Fri, 20 Jul 2007 23:26:17 GMT" }, { "version": "v2", "created": "Fri, 7 Mar 2008 16:38:56 GMT" } ]
2009-05-15T00:00:00
[ [ "Alberts", "Tom", "", "New York University" ], [ "Kozdron", "Michael J.", "", "University of\n Regina" ] ]
0707.3164
Andrew K. Waldron
Karl Hallowell and Andrew Waldron
The Symmetric Tensor Lichnerowicz Algebra and a Novel Associative Fourier-Jacobi Algebra
This is a contribution to the Proceedings of the 2007 Midwest Geometry Conference in honor of Thomas P. Branson, published in SIGMA (Symmetry, Integrability and Geometry: Methods and Applications) at http://www.emis.de/journals/SIGMA/
SIGMA 3 (2007), 089, 12 pages
10.3842/SIGMA.2007.089
null
math.DG gr-qc hep-th math.RT
null
Lichnerowicz's algebra of differential geometric operators acting on symmetric tensors can be obtained from generalized geodesic motion of an observer carrying a complex tangent vector. This relation is based upon quantizing the classical evolution equations, and identifying wavefunctions with sections of the symmetric tensor bundle and Noether charges with geometric operators. In general curved spaces these operators obey a deformation of the Fourier-Jacobi Lie algebra of sp(2,R). These results have already been generalized by the authors to arbitrary tensor and spinor bundles using supersymmetric quantum mechanical models and have also been applied to the theory of higher spin particles. These Proceedings review these results in their simplest, symmetric tensor setting. New results on a novel and extremely useful reformulation of the rank 2 deformation of the Fourier-Jacobi Lie algebra in terms of an associative algebra are also presented. This new algebra was originally motivated by studies of operator orderings in enveloping algebras. It provides a new method that is superior in many respects to common techniques such as Weyl or normal ordering.
[ { "version": "v1", "created": "Fri, 20 Jul 2007 23:11:46 GMT" }, { "version": "v2", "created": "Thu, 13 Sep 2007 11:52:04 GMT" } ]
2008-04-24T00:00:00
[ [ "Hallowell", "Karl", "" ], [ "Waldron", "Andrew", "" ] ]
0707.3165
Marie Treyer
Marie Treyer, David Schiminovich, Ben Johnson, Mark Seibert, Ted Wyder, Tom A. Barlow, Tim Conrow, Karl Forster, Peter G. Friedman, D. Christopher Martin, Patrick Morrissey, Susan G. Neff, Todd Small, Luciana Bianchi, Jose Donas, Timothy M. Heckman, Young-Wook Lee, Barry F. Madore, Bruno Milliard, R. Michael Rich, Alex S. Szalay, Barry Y. Welsh, Sukyoung K. Yi
Extinction Corrected Star Formation Rates Empirically Derived from Ultraviolet-Optical Colors
20 pages, 11 figures, accepted for publication in the ApJS GALEX special issue
null
10.1086/521794
null
astro-ph
null
Using a sample of galaxies from the Sloan Digital Sky Survey spectroscopic catalog with measured star-formation rates (SFRs) and ultraviolet (UV) photometry from the GALEX Medium Imaging Survey, we derived empirical linear correlations between the SFR to UV luminosity ratio and the UV-optical colors of blue sequence galaxies. The relations provide a simple prescription to correct UV data for dust attenuation that best reconciles the SFRs derived from UV and emission line data. The method breaks down for the red sequence population as well as for very blue galaxies such as the local ``supercompact'' UV luminous galaxies and the majority of high redshift Lyman Break Galaxies which form a low attenuation sequence of their own.
[ { "version": "v1", "created": "Fri, 20 Jul 2007 23:21:15 GMT" } ]
2009-11-13T00:00:00
[ [ "Treyer", "Marie", "" ], [ "Schiminovich", "David", "" ], [ "Johnson", "Ben", "" ], [ "Seibert", "Mark", "" ], [ "Wyder", "Ted", "" ], [ "Barlow", "Tom A.", "" ], [ "Conrow", "Tim", "" ], [ "Forster", "Karl", "" ], [ "Friedman", "Peter G.", "" ], [ "Martin", "D. Christopher", "" ], [ "Morrissey", "Patrick", "" ], [ "Neff", "Susan G.", "" ], [ "Small", "Todd", "" ], [ "Bianchi", "Luciana", "" ], [ "Donas", "Jose", "" ], [ "Heckman", "Timothy M.", "" ], [ "Lee", "Young-Wook", "" ], [ "Madore", "Barry F.", "" ], [ "Milliard", "Bruno", "" ], [ "Rich", "R. Michael", "" ], [ "Szalay", "Alex S.", "" ], [ "Welsh", "Barry Y.", "" ], [ "Yi", "Sukyoung K.", "" ] ]
0707.3166
Sannino Francesco
Thomas A. Ryttov and Francesco Sannino (CERN, Bohr Institute and University of Southern Denmark)
Conformal Windows of SU(N) Gauge Theories, Higher Dimensional Representations and The Size of The Unparticle World
RevTeX, 18 pages, 2 figures
Phys.Rev.D76:105004,2007
10.1103/PhysRevD.76.105004
CERN-PH-TH/2007-123
hep-th hep-lat hep-ph
null
We present the conformal windows of SU(N) supersymmetric and nonsupersymmetric gauge theories with vector-like matter transforming according to higher irreducible representations of the gauge group. We determine the fraction of asymptotically free theories expected to develop an infrared fixed point and find that it does not depend on the specific choice of the representation. This result is exact in supersymmetric theories while it is an approximate one in the nonsupersymmetric case. The analysis allows us to size the unparticle world related to the existence of underlying gauge theories developing an infrared stable fixed point. We find that exactly 50 % of the asymptotically free theories can develop an infrared fixed point while for the nonsupersymmetric theories it is circa 25 %. When considering multiple representations, only for the nonsupersymmetric case, the conformal regions quickly dominate over the nonconformal ones. For four representations, 70 % of the asymptotically free space is filled by the conformal region. According to our theoretical landscape survey the unparticle physics world occupies a sizable amount of the particle world, at least in theory space, and before mixing it (at the operator level) with the nonconformal one.
[ { "version": "v1", "created": "Sun, 22 Jul 2007 16:49:00 GMT" } ]
2008-11-26T00:00:00
[ [ "Ryttov", "Thomas A.", "", "CERN, Bohr Institute and\n University of Southern Denmark" ], [ "Sannino", "Francesco", "", "CERN, Bohr Institute and\n University of Southern Denmark" ] ]
0707.3167
James S. Milne
J.S. Milne
Rational Tate classes
null
Mosc. Math. J. 9 (2009), no. 1, 111--141
null
null
math.AG math.NT
null
In despair, as Deligne (2000) put it, of proving the Hodge and Tate conjectures, we can try to find substitutes. For abelian varieties in characteristic zero, Deligne (1982) constructed a theory of Hodge classes having many of the properties that the algebraic classes would have if the Hodge conjecture were known. In this article I investigate whether there exists a theory of "rational Tate classes" on varieties over finite fields having the properties that the algebraic classes would have if the Hodge and Tate conjectures were known. v3. Submitted version.
[ { "version": "v1", "created": "Fri, 20 Jul 2007 23:47:54 GMT" }, { "version": "v2", "created": "Thu, 8 Nov 2007 03:33:38 GMT" }, { "version": "v3", "created": "Tue, 29 Apr 2008 23:53:38 GMT" } ]
2021-01-19T00:00:00
[ [ "Milne", "J. S.", "" ] ]
0707.3168
Jacques Distler
Aaron Bergman and Jacques Distler
Wormholes in Maximal Supergravity
10 pages, LaTeX2e with utarticle.cls
null
null
null
hep-th
null
In this brief note, we reconsider the problem of finding Euclidean wormhole solutions to maximal supergravity in d dimensions. We find that such solutions exists for all d less than or equal to 9. However, we argue that, in toroidally-compactified string theories, these saddle points never contribute to the path integral because of a tension with U-duality.
[ { "version": "v1", "created": "Sat, 21 Jul 2007 00:05:14 GMT" } ]
2007-07-24T00:00:00
[ [ "Bergman", "Aaron", "" ], [ "Distler", "Jacques", "" ] ]
0707.3169
Victor Kaftal
Victor Kaftal (University of Cincinnati), Gary Weiss (University of Cincinnati)
Traces on operator ideals and arithmetic means
41 pages, 1 figure
null
null
null
math.FA math.OA
null
This article - a part of a multipaper project investigating arithmetic mean ideals - investigates the codimension of commutator spaces [I, B(H)] of operator ideals on a separable Hilbert space, i.e., ``How many traces can an ideal support?" We conjecture that the codimension can be only zero, one, or infinity. Using the arithmetic mean (am) operations on ideals introduced by Dykema, Figiel, Weiss, and Wodzicki, and the analogous am operations at infinity that we develop in this article, the conjecture is proven for all ideals not contained in the largest am-infinity stable ideal and not containing the smallest am-stable ideal. It is also proven for all soft-edged ideals (i.e., I= IK(H)) and all soft-complemented ideals (i.e., I= I/K(H)), which include many classical operator ideals. In the process, we prove that an ideal of trace class operators supports a unique trace (up to scalar multiples) if and only if it is am-infinity stable and that, for a principal ideal, am-infinity stability is equivalent to regularity at infinity of the sequence of s-numbers of the generator. Furthermore, we apply trace extension methods to two problems on elementary operators studied by V. Shulman and to Fuglede-Putnam type problems of the second author.
[ { "version": "v1", "created": "Sun, 22 Jul 2007 16:08:19 GMT" } ]
2007-07-24T00:00:00
[ [ "Kaftal", "Victor", "", "University of Cincinnati" ], [ "Weiss", "Gary", "", "University of\n Cincinnati" ] ]
0707.3170
Vladimir Sazonov
Vladimir Sazonov
Inductive Definition and Domain Theoretic Properties of Fully Abstract
50 pages
Logical Methods in Computer Science, Volume 3, Issue 3 (September 10, 2007) lmcs:914
10.2168/LMCS-3(3:7)2007
null
cs.LO
null
A construction of fully abstract typed models for PCF and PCF^+ (i.e., PCF + "parallel conditional function"), respectively, is presented. It is based on general notions of sequential computational strategies and wittingly consistent non-deterministic strategies introduced by the author in the seventies. Although these notions of strategies are old, the definition of the fully abstract models is new, in that it is given level-by-level in the finite type hierarchy. To prove full abstraction and non-dcpo domain theoretic properties of these models, a theory of computational strategies is developed. This is also an alternative and, in a sense, an analogue to the later game strategy semantics approaches of Abramsky, Jagadeesan, and Malacaria; Hyland and Ong; and Nickau. In both cases of PCF and PCF^+ there are definable universal (surjective) functionals from numerical functions to any given type, respectively, which also makes each of these models unique up to isomorphism. Although such models are non-omega-complete and therefore not continuous in the traditional terminology, they are also proved to be sequentially complete (a weakened form of omega-completeness), "naturally" continuous (with respect to existing directed "pointwise", or "natural" lubs) and also "naturally" omega-algebraic and "naturally" bounded complete -- appropriate generalisation of the ordinary notions of domain theory to the case of non-dcpos.
[ { "version": "v1", "created": "Sat, 21 Jul 2007 00:29:38 GMT" }, { "version": "v2", "created": "Fri, 7 Sep 2007 09:41:43 GMT" }, { "version": "v3", "created": "Mon, 10 Sep 2007 08:54:16 GMT" } ]
2015-07-01T00:00:00
[ [ "Sazonov", "Vladimir", "" ] ]
0707.3171
William Halperin
Bo Chen, Sutirtha Mukhopadhyay, W. P. Halperin, Prasenjit Guptasarma, D. G. Hinks
Intrinsic Impurity in the High Temperature Superconductor Bi_2Sr_2CaCu_2O$_{8+\delta}$
10 pages, 5 figures
null
null
null
cond-mat.supr-con cond-mat.str-el
null
The {}^{17}O NMR spectra of Bi_2Sr_2CaCu_2O$_{8+\delta}$ (Bi-2212) single crystals were measured in the temperature range from 4 K to 200 K and magnetic fields from 3 to 29 T, reported here principally at 8 T. The NMR linewidth of the oxygen in the CuO_{2} plane was found to be magnetically broadened with the temperature dependence of a Curie law where the Curie coefficient decreases with increased doping. This inhomogeneous magnetism is an impurity effect intrinsic to oxygen doping and persists unmodified into the superconducting state.
[ { "version": "v1", "created": "Sat, 21 Jul 2007 00:32:03 GMT" } ]
2007-07-24T00:00:00
[ [ "Chen", "Bo", "" ], [ "Mukhopadhyay", "Sutirtha", "" ], [ "Halperin", "W. P.", "" ], [ "Guptasarma", "Prasenjit", "" ], [ "Hinks", "D. G.", "" ] ]
0707.3172
Todor Milanov E
Todor E. Milanov and Hsian-Hua Tseng
Equivariant orbifold structures on the projective line and integrable hierarchies
40 pages, 1 figure
Advances in Mathematics 226 (2011), Issue 1, 641--672
null
null
math.SG math.AG
null
Let $\CP^1_{k,m}$ be the orbifold structure on $\CP^1$ obtained via uniformizing the neighborhoods of 0 and $\infty$ respectively by $z\mapsto z^k$ and $w\mapsto w^m.$ The diagonal action of the torus on the projective line induces naturally an orbifold action on $\CP^1_{k,m}.$ In this paper we prove that if k and m are co-prime then Givental's prediction of the equivariant total descendent Gromov-Witten potential of $\CP^1_{k,m}$ satisfies certain Hirota Quadratic Equations (HQE for short). We also show that after an appropriate change of the variables, similar to Getzler's change in the equivariant Gromov-Witten theory of $\CP^1$, the HQE turn into the HQE of the 2-Toda hierarchy, i.e., the Gromov-Witten potential of $\CP^1_{k,m}$ is a tau-function of the 2-Toda hierarchy. More precisely, we obtain a sequence of tau-functions of the 2-Toda hierarchy from the descendent potential via some translations. The later condition, that all tau-functions in the sequence are obtained from a single one via translations, imposes a serious constraint on the solution of the 2-Toda hierarchy. Our theorem leads to the discovery of a new integrable hierarchy (we suggest to be called the Equivariant Bi-graded Toda Hierarchy). We conjecture that this new hierarchy governs, i.e., uniquely determines, the equivariant Gromov-Witten invariants of $\CP^1_{k,m}.$
[ { "version": "v1", "created": "Sat, 21 Jul 2007 00:33:21 GMT" } ]
2011-01-20T00:00:00
[ [ "Milanov", "Todor E.", "" ], [ "Tseng", "Hsian-Hua", "" ] ]
0707.3173
James S. Milne
J.S. Milne
Points on Shimura varieties over finite fields: the conjecture of Langlands and Rapoport
null
null
null
null
math.NT math.AG
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We state an improved version of the conjecture of Langlands and Rapoport, and we prove the conjecture for a large class of Shimura varieties. In particular, we obtain the first proof of the (original) conjecture for Shimura varieties of PEL-type.
[ { "version": "v1", "created": "Sat, 21 Jul 2007 00:34:34 GMT" }, { "version": "v2", "created": "Sat, 26 Jul 2008 18:38:29 GMT" }, { "version": "v3", "created": "Tue, 18 Nov 2008 01:35:11 GMT" }, { "version": "v4", "created": "Wed, 11 Nov 2009 18:36:04 GMT" } ]
2009-11-11T00:00:00
[ [ "Milne", "J. S.", "" ] ]
0707.3174
Jason Bandlow
Jason Bandlow, Gregg Musiker
A new characterization for the m-quasiinvariants of S_n and explicit basis for two row hook shapes
26 pages, uses youngtab.sty
J. Combin. Theory Ser. A 115 (2008), no. 8, 1333--1357
null
null
math.CO
null
In 2002, Feigin and Veselov defined the space of m-quasiinvariants for any Coxeter group, building on earlier work of Chalykh and Veselov. While many properties of those spaces were proven from this definition, an explicit computation of a basis was only done in certain cases. In particular, Feigin and Veselov computed bases for the m-quasiinvariants of dihedral groups, including S_3, and Felder and Veselov computed the non-symmetric m-quasiinvariants of lowest degree for general S_n. In this paper, we provide a new characterization of the m-quasiinvariants of S_n, and use this to provide a basis for the isotypic component indexed by the partition [n-1,1]. This builds on a previous paper in which we computed a basis for S_3 via combinatorial methods.
[ { "version": "v1", "created": "Sat, 21 Jul 2007 00:35:19 GMT" }, { "version": "v2", "created": "Mon, 23 Jul 2007 20:00:15 GMT" } ]
2008-10-21T00:00:00
[ [ "Bandlow", "Jason", "" ], [ "Musiker", "Gregg", "" ] ]
0707.3175
Aydin Sezgin
Aydin Sezgin and Oliver Henkel
Stacked OSTBC: Error Performance and Rate Analysis
IEEE Transactions on Signal Processing, accepted
null
10.1109/TSP.2007.896025
null
cs.IT math.IT
null
It is well known, that the Alamouti scheme is the only space-time code from orthogonal design achieving the capacity of a multiple-input multiple-output (MIMO) wireless communication system with n_T=2 transmit antennas and n_R=1 receive antenna. In this work, we propose the n-times stacked Alamouti scheme for n_T=2n transmit antennas and show that this scheme achieves the capacity in the case of n_R=1 receive antenna. This result may regarded as an extension of the Alamouti case. For the more general case of more than one receive antenna, we show that if the number of transmit antennas is higher than the number of receive antennas we achieve a high portion of the capacity with this scheme. Further, we show that the MIMO capacity is at most twice the rate achieved with the proposed scheme for all SNR. We derive lower and upper bounds for the rate achieved with this scheme and compare it with upper and lower bounds for the capacity. In addition to the capacity analysis based on the assumption of a coherent channel, we analyze the error rate performance of the stacked OSTBC with the optimal ML detector and with the suboptimal lattice-reduction (LR) aided zero-forcing detector. We compare the error rate performance of the stacked OSTBC with spatial multiplexing (SM) and full-diversity achieving schemes. Finally, we illustrate the theoretical results by numerical simulations.
[ { "version": "v1", "created": "Sat, 21 Jul 2007 01:09:00 GMT" } ]
2009-11-13T00:00:00
[ [ "Sezgin", "Aydin", "" ], [ "Henkel", "Oliver", "" ] ]
0707.3176
Jiwoong Park
Y.H.Ahn, Wei Tsen, Bio Kim, Yung Woo Park, Jiwoong Park
Photocurrent Imaging of p-n Junctions and Local Defects in Ambipolar Carbon Nanotube Transistors
5 pages, 5 figures
null
10.1021/nl071536m
null
cond-mat.mtrl-sci cond-mat.mes-hall
null
We use scanning photocurrent microscopy (SPCM) to investigate the properties of internal p-n junctions as well as local defects in ambipolar carbon nanotube (CNT) transistors. Our SPCM images show strong signals near metal contacts whose polarity and positions change depending on the gate bias. SPCM images analyzed in conjunction with the overall conductance also indicate the existence and gate-dependent evolution of internal p-n junctions near contacts in the n-type operation regime. To determine the p-n junction position and the depletion width with a nanometer scale resolution, a Gaussian fit was used. We also measure the electric potential profile of CNT devices at different gate biases, which shows that both local defects and induced electric fields can be imaged using the SPCM technique. Our experiment clearly demonstrates that SPCM is a valuable tool for imaging and optimizing electrical and optoelectronic properties of CNT based devices.
[ { "version": "v1", "created": "Sat, 21 Jul 2007 01:14:01 GMT" } ]
2015-05-13T00:00:00
[ [ "Ahn", "Y. H.", "" ], [ "Tsen", "Wei", "" ], [ "Kim", "Bio", "" ], [ "Park", "Yung Woo", "" ], [ "Park", "Jiwoong", "" ] ]
0707.3177
James S. Milne
J.S. Milne
Towards a proof of the conjecture of Langlands and Rapoport
Text for a talk April 28, 2000, at the Conference on Galois Representations, Automorphic Representations and Shimura Varieties, Institut Henri Poincare, Paris, April 24-29, 2000
null
null
null
math.NT math.AG
null
A conference talk discussing the conjecture of Langlands and Rapoport concerning the structure of the points on a Shimura variety modulo a prime of good reduction.
[ { "version": "v1", "created": "Sat, 21 Jul 2007 01:42:59 GMT" } ]
2007-07-24T00:00:00
[ [ "Milne", "J. S.", "" ] ]
0707.3178
Osamu Fujino
Osamu Fujino
Vanishing theorems for toric polyhedra
15 pages; title changed, a completely revised and expanded version, v3: very minor modifications
null
null
null
math.AG
null
A toric polyhedron is a reduced closed subscheme of a toric variety that are partial unions of the orbits of the torus action. We prove vanishing theorems for toric polyhedra. We also give a proof of the $E_1$-degeneration of Hodge to de Rham type spectral sequence for toric polyhedra in any characteristic. Finally, we give a very powerful extension theorem for ample line bundles.
[ { "version": "v1", "created": "Sat, 21 Jul 2007 02:00:55 GMT" }, { "version": "v2", "created": "Sat, 8 Sep 2007 06:14:47 GMT" }, { "version": "v3", "created": "Mon, 4 Feb 2008 03:15:21 GMT" } ]
2008-02-04T00:00:00
[ [ "Fujino", "Osamu", "" ] ]
0707.3179
Gregg Musiker
Gregg Musiker
Combinatorial Aspects of Elliptic Curves
29 pages, Section 2 presented at FPSAC 2006
Seminaire Lotharingien de Combinatoire, vol. 56 (2007) Art. B56f
null
null
math.CO math.NT
null
Given an elliptic curve C, we study here $N_k = #C(F_{q^k})$, the number of points of C over the finite field F_{q^k}. This sequence of numbers, as k runs over positive integers, has numerous remarkable properties of a combinatorial flavor in addition to the usual number theoretical interpretations. In particular we prove that $N_k = - W_k(q, - N_1)$ where W_k(q,t) is a (q,t)-analogue of the number of spanning trees of the wheel graph. Additionally we develop a determinantal formula for N_k where the eigenvalues can be explicitly written in terms of q, N_1, and roots of unity. We also discuss here a new sequence of bivariate polynomials related to the factorization of N_k, which we refer to as elliptic cyclotomic polynomials because of their various properties.
[ { "version": "v1", "created": "Mon, 23 Jul 2007 18:38:01 GMT" } ]
2007-07-24T00:00:00
[ [ "Musiker", "Gregg", "" ] ]
0707.3180
Xuezhao Bao
Xuezhao Bao
Two Trends of Composition Variation of Zircons and Their Significance in Origin Discrimination
11 pages, 8 figures, 1 table
ActaPetrolog.Mineral.15:404-410,1995
null
null
physics.geo-ph astro-ph cond-mat.mtrl-sci
null
Zircons can crystallize in a wide range of physical and chemical conditions. At the same time, they have high stability and durability. Therefore zircons can grow and survive in a variety of geological processes. In addition, the diffusivity of chemical compositions in their crystals is very low. Consequently,we can trace back the evolution history of the planetary materials containing zircon by zircon U-Th-Pb geochronology and geochemistry studies. However, this depends on our ability to decipher its genesis,namely magmatic or metamorphic origins. In this paper, we have found that there are obvious differences between magmatic and metamorphic zircons in their chemical composition zonations. The magmatic zircons exhibit composition zonation of increasing HfO2, and (UO2 + ThO2) content and decreasing ZrO2/HfO2 ratio and ZrO2 content from inner to outer parts within each growth zone or from core to rim of a crysta1. The metamorphic zircons exhibit compositional variation trend opposite to that of magmatic (igneous) zircons,tending to decrease in HfO2, (UO2+ ThO2)and increase in ZrO2/HfO2 ratio and ZrO2 from core to rim of a crystal. These chemical composition variation trends are thought to be controlled by the crystal chemical features of ions themselves and the evolution trends of magmatism and metamorphism respectively, and can be used to identify the genesis of zircons. Their morphological features are also discussed.
[ { "version": "v1", "created": "Mon, 23 Jul 2007 03:51:51 GMT" }, { "version": "v2", "created": "Wed, 15 Aug 2007 19:42:13 GMT" } ]
2008-11-26T00:00:00
[ [ "Bao", "Xuezhao", "" ] ]
0707.3181
Xuezhao Bao
Xuezhao Bao, Gan Xiaochun
The Minerageny of Two Groups of Zircons from Plagioclase- Amphibolite of Mayuan Group in Northern Fujian
10 pages, 5 figures, 2 tables
ActaPetrolog.Mineral.15:73-79,1996
null
null
physics.geo-ph astro-ph
null
Zircons can crystallize in a wide range of physical and chemical conditions. At the same time, they have high stability and durability. Therefore zircons can grow and survive in a variety of geological processes. In addition, the diffusivity of chemical compositions in their crystals is very low. Consequently,we can trace back the evolution history of the planetary materials containing zircon with zircon U-Th-Pb geochronology and geochemistry studies. However, this depends on our ability to decipher its genesis, namely magmatic or metamorphic origins. In this paper, magmatic and metamorphic zircons were found from plagioclase-amphibolite samples. Their geneses have been determined by zircon morphology, chemical composition zonations and geological field setting combined with their zircon U-Th-Pb ages. We have found obvious differences in micro-scale Raman spectra between these magmatic and metamorphic zircons. The magmatic zircons exhibit a high sloping background in their Raman spectra, but the metamorphic zircons exhibit a low horizontal background in their Raman spectra, which suggest that the magmatic zircons may contain a much higher concentration of fluorescent impurities than the metamorphic zircons. Moreover, reverse variation trends in Raman spectrum peak intensities from core to rim of a crystal between the magmatic and metamorphic zircons have been found. We think that this can be attributed to their reverse chemical composition zonations. These differences can be used to distinguish magmatic and metamorphic zircons.
[ { "version": "v1", "created": "Mon, 23 Jul 2007 03:55:29 GMT" }, { "version": "v2", "created": "Wed, 15 Aug 2007 19:46:16 GMT" } ]
2008-11-26T00:00:00
[ [ "Bao", "Xuezhao", "" ], [ "Xiaochun", "Gan", "" ] ]
0707.3182
JoAnne Hewett
JoAnne Hewett and Thomas Rizzo (SLAC)
Collider Signals of Gravitational Fixed Points
33 pages
JHEP 0712:009,2007
10.1088/1126-6708/2007/12/009
SLAC-PUB-12689
hep-ph hep-ex hep-th
null
Recent studies have shown that the poor perturbative behavior of General Relativity in the ultraviolet regime may be ameliorated by the existence of a non-Gaussian fixed point which renders the theory asymptotically safe and possibly non-perturbatively renormalizable. This results in a running of the (effective) gravitational coupling such that gravity becomes weaker at high energies. We parameterize this effective coupling with a form factor and study its consequences at the LHC and ILC in models with large extra dimensions or warped extra dimensions. We find significant effects in the processes of Kaluza-Klein (KK) graviton exchange or resonant KK graviton production in both the Drell-Yan reaction as well as in $e^+e^-\to f\bar f$. On the otherhand, processes leading to KK graviton emission show qualitatively less sensitivity to the presence of a form factor. In addition, we examine tree-level perturbative unitarity in $2\to 2$ gravity-mediated scattering and find that this form factor produces a far better behaved amplitude at large center of mass energies.
[ { "version": "v1", "created": "Sat, 21 Jul 2007 04:53:32 GMT" } ]
2009-01-06T00:00:00
[ [ "Hewett", "JoAnne", "", "SLAC" ], [ "Rizzo", "Thomas", "", "SLAC" ] ]
0707.3183
Sundaresan Athinarayanan
A. Sundaresan, R. Bhargavi, N. Rangarajan, U. Siddesh and C. N. R. Rao
Ferromagnetism as a universal feature of nanoparticles of the otherwise nonmagnetic oxides
6 pages, 4 figures
Physical Review B 74, 161306(R) (2006)
10.1103/PhysRevB.74.161306
null
cond-mat.mtrl-sci
null
Room-temperature ferromagnetism has been observed in the nanoparticles (7 - 30 nm dia) of nonmagnetic oxides such as CeO2, Al2O3, ZnO, In2O3 and SnO2. The saturated magnetic moments in CeO_2 and Al_2O_3 nanoparticles are comparable to those observed in transition metal doped wide band semiconducting oxides. The other oxide nanoparticles show somewhat lower values of magnetization but with a clear hysteretic behavior. Conversely, the bulk samples obtained by sintering the nanoparticles at high temperatures in air or oxygen became diamagnetic. As there were no magnetic impurities present, we assume that the origin of ferromagnetism may be due to the exchange interactions between localized electron spin moments resulting from oxygen vacancies at the surfaces of nanoparticles. We suggest that ferromagnetism may be a universal characteristic of nanopartilces of metal oxides
[ { "version": "v1", "created": "Sat, 21 Jul 2007 04:58:13 GMT" } ]
2007-07-24T00:00:00
[ [ "Sundaresan", "A.", "" ], [ "Bhargavi", "R.", "" ], [ "Rangarajan", "N.", "" ], [ "Siddesh", "U.", "" ], [ "Rao", "C. N. R.", "" ] ]
0707.3184
Xuezhao Bao
Xuezhao Bao, Huiming Li, Songnian Lu
A Raman spectroscopic study of zircons on micro-scale and Its significance in explaining the origin of zircons
10 pages, 4 figures, 2 tables
Sci.Geol.Sin.33:455-462,1998
null
null
physics.geo-ph astro-ph physics.chem-ph
null
The magmatic and metamorphic zircons were investigated with Raman spectrum microprobe analysis. We found notable differences between these two kinds of zircons exhibited by the variation trend of Raman peak intensity from core to rim of a crystal. In magmatic zircons, the intensity and the ratio H/W of Raman spectrum peaks gradually decrease from core to rim of a crystal, which is produced by an increase in metamictization degree and suggests an increase in U and Th concentrations from core to rim. In metamorphic zircons, there are two kinds of crystals according to their Raman spectra: the first group of zircons exhibits a variation trend opposite to those of magmatic zircons, tending to increase in the Raman peak intensity and H/W value from core to rim of a crystal, which is produced by a decrease in metamictization degree and indicates a decrease of U and Th concentrations from core to rim of a crystal. The second group of zircons exhibits no change in Raman peak intensity and H/W value through a crystal. The data of infrared and Raman spectra of these crystals show that they are well crystallized and have no lattice destruction induced by metamictization, and are thought to crystallize in high temperature stages of metamorphism. During these stages, the U and Th ions have been removed by metamorphic fluids from the parent rocks of these zircons. The other difference between magmatic and metamorphic zircons is the background level of their Raman spectra, which is high and sloped in magmatic zircons, but low and horizontal in metamorphic zircons. The differences between magmatic and metamorphic zircons can be used to identify the genesis of zircons and understand the origin and evolution history of their parent rocks.
[ { "version": "v1", "created": "Mon, 23 Jul 2007 03:58:19 GMT" }, { "version": "v2", "created": "Wed, 15 Aug 2007 19:48:41 GMT" } ]
2008-11-26T00:00:00
[ [ "Bao", "Xuezhao", "" ], [ "Li", "Huiming", "" ], [ "Lu", "Songnian", "" ] ]
0707.3185
Pascal Weil
Fr\'ed\'erique Bassino (IGM), Cyril Nicaud (IGM), Pascal Weil (LaBRI)
Random generation of finitely generated subgroups of a free group
null
International Journal of Algebra and Computation 18 (2008) 1-31
null
null
math.GR math.CO
null
We give an efficient algorithm to randomly generate finitely generated subgroups of a given size, in a finite rank free group. Here, the size of a subgroup is the number of vertices of its representation by a reduced graph such as can be obtained by the method of Stallings foldings. Our algorithm randomly generates a subgroup of a given size n, according to the uniform distribution over size n subgroups. In the process, we give estimates of the number of size n subgroups, of the average rank of size n subgroups, and of the proportion of such subgroups that have finite index. Our algorithm has average case complexity $\O(n)$ in the RAM model and $\O(n^2\log^2n)$ in the bitcost model.
[ { "version": "v1", "created": "Sat, 21 Jul 2007 05:22:00 GMT" } ]
2010-06-21T00:00:00
[ [ "Bassino", "Frédérique", "", "IGM" ], [ "Nicaud", "Cyril", "", "IGM" ], [ "Weil", "Pascal", "", "LaBRI" ] ]
0707.3186
Damien Chablat
Anatoly Pashkevich (Robotic Laboratory), Philippe Wenger (IRCCyN), Damien Chablat (IRCCyN)
Kinematic and stiffness analysis of the Orthoglide, a PKM with simple, regular workspace and homogeneous performances
null
Dans International Conference On Robotics And Automation ICRA, Rome : Italie (04/2007)
null
null
cs.RO
null
The Orthoglide is a Delta-type PKM dedicated to 3-axis rapid machining applications that was originally developed at IRCCyN in 2000-2001 to meet the advantages of both serial 3-axis machines (regular workspace and homogeneous performances) and parallel kinematic architectures (good dynamic performances and stiffness). This machine has three fixed parallel linear joints that are mounted orthogonally. The geometric parameters of the Orthoglide were defined as function of the size of a prescribed cubic Cartesian workspace that is free of singularities and internal collision. The interesting features of the Orthoglide are a regular Cartesian workspace shape, uniform performances in all directions and good compactness. In this paper, a new method is proposed to analyze the stiffness of overconstrained Delta-type manipulators, such as the Orthoglide. The Orthoglide is then benchmarked according to geometric, kinematic and stiffness criteria: workspace to footprint ratio, velocity and force transmission factors, sensitivity to geometric errors, torsional stiffness and translational stiffness.
[ { "version": "v1", "created": "Sat, 21 Jul 2007 05:24:17 GMT" } ]
2007-07-24T00:00:00
[ [ "Pashkevich", "Anatoly", "", "Robotic Laboratory" ], [ "Wenger", "Philippe", "", "IRCCyN" ], [ "Chablat", "Damien", "", "IRCCyN" ] ]
0707.3187
Ashkan Nikeghbali
Ashkan Nikeghbali and Marc Yor
The barnes G function and its relations with sums and products of generalized Gamma convolution variables
null
null
null
null
math.PR
null
We give a probabilistic interpretation for the Barnes G-function which appears in random matrix theory and in analytic number theory in the important moments conjecture due to Keating-Snaith for the Riemann zeta function, via the analogy with the characteristic polynomial of random unitary matrices. We show that the Mellin transform of the characteristic polynomial of random unitary matrices and the Barnes G-function are intimately related with products and sums of gamma, beta and log-gamma variables. In particular, we show that the law of the modulus of the characteristic polynomial of random unitary matrices can be expressed with the help of products of gamma or beta variables, and that the reciprocal of the Barnes G-function has a L\'{e}vy-Khintchin type representation. These results lead us to introduce the so called generalized gamma convolution variables.
[ { "version": "v1", "created": "Mon, 23 Jul 2007 19:17:50 GMT" } ]
2007-07-24T00:00:00
[ [ "Nikeghbali", "Ashkan", "" ], [ "Yor", "Marc", "" ] ]
0707.3188
Terence C. Tao
Rowan Killip, Terence Tao, Monica Visan
The cubic nonlinear Schr\"odinger equation in two dimensions with radial data
49 pages, no figures, submitted, Annals of Math. Various corrections
null
null
null
math.AP
null
We establish global well-posedness and scattering for solutions to the mass-critical nonlinear Schr\"odinger equation $iu_t + \Delta u = \pm |u|^2 u$ for large spherically symmetric L^2_x(\R^2) initial data; in the focusing case we require, of course, that the mass is strictly less than that of the ground state. As a consequence, we deduce that in the focusing case, any spherically symmetric blowup solution must concentrate at least the mass of the ground state at the blowup time. We also establish some partial results towards the analogous claims in other dimensions and without the assumption of spherical symmetry.
[ { "version": "v1", "created": "Sat, 21 Jul 2007 05:37:10 GMT" }, { "version": "v2", "created": "Tue, 4 Mar 2008 21:24:05 GMT" } ]
2008-03-04T00:00:00
[ [ "Killip", "Rowan", "" ], [ "Tao", "Terence", "" ], [ "Visan", "Monica", "" ] ]
0707.3189
Jorgen Rasmussen
Jorgen Rasmussen and Paul A. Pearce
Fusion Algebras of Logarithmic Minimal Models
22 pages, v2: comments added
J.Phys.A40:13711-13734,2007
10.1088/1751-8113/40/45/013
null
hep-th cond-mat.stat-mech math-ph math.MP
null
We present explicit conjectures for the chiral fusion algebras of the logarithmic minimal models LM(p,p') considering Virasoro representations with no enlarged or extended symmetry algebra. The generators of fusion are countably infinite in number but the ensuing fusion rules are quasi-rational in the sense that the fusion of a finite number of representations decomposes into a finite direct sum of representations. The fusion rules are commutative, associative and exhibit an sl(2) structure but require so-called Kac representations which are reducible yet indecomposable representations of rank 1. In particular, the identity of the fundamental fusion algebra is in general a reducible yet indecomposable Kac representation of rank 1. We make detailed comparisons of our fusion rules with the results of Gaberdiel and Kausch for p=1 and with Eberle and Flohr for (p,p')=(2,5) corresponding to the logarithmic Yang-Lee model. In the latter case, we confirm the appearance of indecomposable representations of rank 3. We also find that closure of a fundamental fusion algebra is achieved without the introduction of indecomposable representations of rank higher than 3. The conjectured fusion rules are supported, within our lattice approach, by extensive numerical studies of the associated integrable lattice models. Details of our lattice findings and numerical results will be presented elsewhere. The agreement of our fusion rules with the previous fusion rules lends considerable support for the identification of the logarithmic minimal models LM(p,p') with the augmented c_{p,p'} (minimal) models defined algebraically.
[ { "version": "v1", "created": "Sat, 21 Jul 2007 06:23:21 GMT" }, { "version": "v2", "created": "Fri, 21 Sep 2007 04:10:05 GMT" } ]
2008-11-26T00:00:00
[ [ "Rasmussen", "Jorgen", "" ], [ "Pearce", "Paul A.", "" ] ]
0707.3190
Nikolai V. Mitskievich
N.V. Mitskievich
Electromagnetism and perfect fluids interplay in multidimensional spacetimes
5 pages, a talk delivered at the 11th Marcel Grossmann Meeting (2006)
null
10.1142/9789812834300_0140
null
gr-qc
null
We consider fields in (D>2)-dimensional spacetime, whose potential is r-form (skew-symmetric tensor of rank r), the field tensor F being its exterior derivative and the Lagrangian, a function of the quadratic invariant I of this tensor. It is shown that vector field (r=1) describes electromagnetic field only for D=4. In particular, for D=3 and the Lagrangean L as any function of the above-mentioned invariant, the (r=1)-field has energy-momentum tensor identical with that of a perfect fluid whose equation of state depends on the choice of L(I).
[ { "version": "v1", "created": "Sat, 21 Jul 2007 06:58:25 GMT" } ]
2016-11-15T00:00:00
[ [ "Mitskievich", "N. V.", "" ] ]
0707.3191
Eric Blackman
Eric G. Blackman (Univ. of Rochester)
Toward Coupling Flow Driven and Magnetically Driven Dynamos
20 pages, accepted by New Journal of Physics as a special issue article
NewJ.Phys.9:309,2007
10.1088/1367-2630/9/8/309
null
astro-ph physics.plasm-ph
null
Most large scale dynamo research for astrophysical rotators focuses on interior flow driven helical dynamos (FDHDs), but larger scale coronal fields most directly influence observations. It is thus important to understand the relationship between coronal and interior fields. Coronal field relaxation is actually a type of magnetically dominated helical dynamo (MDHD). MDHDs also occur in fusion plasma devices where they drive a system toward its relaxed state in response to magnetic helicity injection that otherwise drives the system away from this state. Global scale fields of astrophysical rotators and jets are thus plausibly produced by a direct coupling between an interior FDHD and a coronal MDHD, interfaced by magnetic helicity transport through their mutual boundary. Tracking the magnetic helicity also elucidates how both FDHD and MDHDs evolve and saturate. The utility of magnetic helicity is unhampered by its non-gauge invariance since physical fields can always be recovered.
[ { "version": "v1", "created": "Sat, 21 Jul 2007 06:59:00 GMT" }, { "version": "v2", "created": "Thu, 26 Jul 2007 17:52:20 GMT" } ]
2008-11-26T00:00:00
[ [ "Blackman", "Eric G.", "", "Univ. of Rochester" ] ]
0707.3192
Nikolai V. Mitskievich
Nikolai V. Mitskievich and Luis I. Lopez Benitez
Zeeman-type dragging in the Kerr--Newman and NUT spacetimes
5 pages, a talk delivered at the 11th Marcel Grossmann Meeting (2006)
null
10.1142/9789812834300_0384
null
gr-qc
null
In this communication we discuss two distinct Zeeman-type gravitomagnetic effects deserving attention since they can be easily characterized in their exact form, not via approximation procedures. Some observations are also made on gravitoelectric effects.
[ { "version": "v1", "created": "Sat, 21 Jul 2007 07:27:31 GMT" } ]
2016-11-15T00:00:00
[ [ "Mitskievich", "Nikolai V.", "" ], [ "Benitez", "Luis I. Lopez", "" ] ]
0707.3193
Nikolai V. Mitskievich
Nikolai V. Mitskievich, Maria G. Medina Guevara and Hector Vargas Rodriguez
Nariai--Bertotti--Robinson spacetimes as a building material for one-way wormholes with horizons, but without singularity
5 pages, a talk delivered at the 11th Marcel Grossmann Meeting (2006)
null
10.1142/9789812834300_0355
null
gr-qc
null
We discuss the problem of wormholes from the viewpoint of gluing together two Reissner--Nordstr\"om-type universes while putting between them a segment of the Nariai-type world (in both cases there are also present electromagnetic fields as well as the cosmological constant). Such a toy wormhole represents an example of one-way topological communication free from causal paradoxes, though involving a travel to next spacetime sheet since one has to cross at least a pair of horizons through which the spacetimes' junction occurs. We also consider the use of thin shells in these constructions. Such a ``material'' for wormholes we choose taking into account specific properties of the Nariai--Bertotti--Robinson spacetimes.
[ { "version": "v1", "created": "Sat, 21 Jul 2007 07:50:18 GMT" } ]
2016-11-15T00:00:00
[ [ "Mitskievich", "Nikolai V.", "" ], [ "Guevara", "Maria G. Medina", "" ], [ "Rodriguez", "Hector Vargas", "" ] ]
0707.3194
Hiroshi Yokoya
Kaoru Hagiwara, Kentarou Mawatari and Hiroshi Yokoya
T-odd asymmetries in radiative top-quark decays
21 pages, 9 figures; discussions for the decay of polarized top-quarks added in a new chapter, references added, version to appear in JHEP
JHEP 0712:041,2007
10.1088/1126-6708/2007/12/041
KEK-TH-1140, KIAS-P07005
hep-ph
null
We study the angular distribution of the charged lepton in the top-quark decay into a bottom quark and a W boson which subsequently decays into \ell\nu_{\ell}, when a hard gluon is radiated off. The absorptive part of the t \to bWg decay amplitudes, which gives rise to T-odd asymmetries in the distribution, is calculated at the one-loop level in perturbative QCD. The asymmetries at a few percent level are predicted, which may be observable at future colliders.
[ { "version": "v1", "created": "Sat, 21 Jul 2007 08:16:18 GMT" }, { "version": "v2", "created": "Thu, 13 Dec 2007 13:23:44 GMT" } ]
2010-02-03T00:00:00
[ [ "Hagiwara", "Kaoru", "" ], [ "Mawatari", "Kentarou", "" ], [ "Yokoya", "Hiroshi", "" ] ]
0707.3195
Mehdi Nadjafikhah
Mehdi Nadjafikhah and Ahmad-Reza Forough
Galilean geometry of motions
14 pages
Applied Sciences, Vol.11, pp. 91-105, 2009
null
null
math.DG
null
In this paper we show that Galilean group is a matrix Lie group and find its structure. Then provide the invariants of special Galilean geometry of motions, by Olver's method of moving coframes, we also find the corresponding $\{e\}-$structure.
[ { "version": "v1", "created": "Sat, 21 Jul 2007 08:29:29 GMT" } ]
2012-03-13T00:00:00
[ [ "Nadjafikhah", "Mehdi", "" ], [ "Forough", "Ahmad-Reza", "" ] ]
0707.3196
Masaharu Iwasaki
Takahiko Fukutome and Masaharu Iwasaki
Effect of Soft Modes on the Shear Viscosity of Quark Matter
8 pages, 11 figures
Prog.Theor.Phys.119:991-1004,2008
10.1143/PTP.119.991
null
hep-ph
null
We calculate shear viscosity of the quark matter at finite temperature and density. If we assume that the quark interacts with the soft mode, which is a collective mode of quark-antiquark pair, the self energy of the quark is calculated by using the quasi-particle random phase approximation. It is shown that its imaginary part is large and the mean free path of the quark is short. With the use of the Kubo formula, the shear viscosity of quark matter becomes small. The Reynolds number of the quark matter is estimated to be about $3\sim 30$. As the temperature increases, the shear viscosity increases gradually for $T>200{\rm MeV}$. Moreover it is shown that the shear viscosity is not sensitive to the chemical potential.
[ { "version": "v1", "created": "Sat, 21 Jul 2007 08:30:07 GMT" } ]
2008-11-26T00:00:00
[ [ "Fukutome", "Takahiko", "" ], [ "Iwasaki", "Masaharu", "" ] ]
0707.3197
Masaki Tezuka
Masaki Tezuka, Ryotaro Arita and Hideo Aoki
Phase diagram for the one-dimensional Hubbard-Holstein model: A density-matrix renormalization group study
12 pages, 14 figures, submitted to Phys. Rev. B
Phys. Rev. B 76, 155114 (2007)
10.1103/PhysRevB.76.155114
null
cond-mat.str-el cond-mat.supr-con
null
Phase diagram of the Hubbard-Holstein model in the coexistence of electron-electron and electron-phonon interactions has been theoretically obtained with the density-matrix renormalization group method for one-dimensional (1D) systems, where an improved warm-up (the recursive sweep) procedure has enabled us to calculate various correlation functions. We have examined the cases of (i) the systems half-filled by electrons for the full parameter space spanned by the electron-electron and electron-phonon coupling constants and the phonon frequency, (ii) non-half-filled system, and (iii) trestle lattice. For (i), we have detected a region where both the charge and on-site pairing correlations decay with power-laws in real space, which suggests a metallic behavior. While pairing correlations are not dominant in (i), we have found that they become dominant as the system is doped in (ii), or as the electronic band structure is modified (with a broken electron-hole symmetry) in (iii) in certain parameter regions.
[ { "version": "v1", "created": "Sat, 21 Jul 2007 09:22:10 GMT" }, { "version": "v2", "created": "Mon, 3 Sep 2007 20:26:40 GMT" } ]
2008-01-16T00:00:00
[ [ "Tezuka", "Masaki", "" ], [ "Arita", "Ryotaro", "" ], [ "Aoki", "Hideo", "" ] ]
0707.3198
Jan Palczewski
Jan Palczewski and Lukasz Stettner
Growth-optimal portfolios under transaction costs
32 pages
null
null
null
q-fin.PM math.OC math.PR
null
This paper studies a portfolio optimization problem in a discrete-time Markovian model of a financial market, in which asset price dynamics depend on an external process of economic factors. There are transaction costs with a structure that covers, in particular, the case of fixed plus proportional costs. We prove that there exists a self-financing trading strategy maximizing the average growth rate of the portfolio wealth. We show that this strategy has a Markovian form. Our result is obtained by large deviations estimates on empirical measures of the price process and by a generalization of the vanishing discount method to discontinuous transition operators.
[ { "version": "v1", "created": "Sat, 21 Jul 2007 09:25:30 GMT" } ]
2008-12-02T00:00:00
[ [ "Palczewski", "Jan", "" ], [ "Stettner", "Lukasz", "" ] ]
0707.3199
Schoeffel Laurent
Laurent Schoeffel (DAPNIA, Saclay)
Review of diffraction at HERA and Tevatron
3 pages (2 col.), 6 figures, proceedings of the conference Photon2007, Paris 9-13 July 2007
Nucl.Phys.Proc.Suppl.184:81-84,2008
10.1016/j.nuclphysbps.2008.09.142
null
hep-ph
null
We present and discuss the recent results on diffraction from the HERA and Tevatron experiments.
[ { "version": "v1", "created": "Sat, 21 Jul 2007 11:04:02 GMT" } ]
2008-12-18T00:00:00
[ [ "Schoeffel", "Laurent", "", "DAPNIA, Saclay" ] ]
0707.3200
Francois Treussart
Vincent Jacques (LPQM), John Murray (LPQM), Fran\c{c}ois Marquier (EM2C), Dominique Chauvat (LPQM), Fr\'ed\'eric Grosshans (LPQM), Fran\c{c}ois Treussart (LPQM), Jean-Fran\c{c}ois Roch (LPQM)
Enhancing single-molecule photostability by optical feedback from quantum-jump detection
null
null
10.1063/1.3013843
null
quant-ph physics.chem-ph physics.optics
null
We report an optical technique that yields an enhancement of single-molecule photostability, by greatly suppressing photobleaching pathways which involve photoexcitation from the triplet state. This is accomplished by dynamically switching off the excitation laser when a quantum-jump of the molecule to the triplet state is optically detected. This procedure leads to a lengthened single-molecule observation time and an increased total number of detected photons. The resulting improvement in photostability unambiguously confirms the importance of photoexcitation from the triplet state in photobleaching dynamics, and may allow the investigation of new phenomena at the single-molecule level.
[ { "version": "v1", "created": "Sat, 21 Jul 2007 09:44:18 GMT" } ]
2009-11-13T00:00:00
[ [ "Jacques", "Vincent", "", "LPQM" ], [ "Murray", "John", "", "LPQM" ], [ "Marquier", "François", "", "EM2C" ], [ "Chauvat", "Dominique", "", "LPQM" ], [ "Grosshans", "Frédéric", "", "LPQM" ], [ "Treussart", "François", "", "LPQM" ], [ "Roch", "Jean-François", "", "LPQM" ] ]
0707.3201
Alexander Herlert
C. Yazidjian, G. Audi, D. Beck, K. Blaum, S. George, C. Guenaut, F. Herfurth, A. Herlert, A. Kellerbauer, H.-J. Kluge, D. Lunney, L. Schweikhard
Evidence for a breakdown of the Isobaric Multiplet Mass Equation: A study of the A=35, T=3/2 isospin quartet
8 pages, 4 figures
Phys.Rev.C76:024308,2007
10.1103/PhysRevC.76.024308
null
nucl-ex
null
Mass measurements on radionuclides along the potassium isotope chain have been performed with the ISOLTRAP Penning trap mass spectrometer. For 35K T1/2=178ms) to 46K (T1/2=105s) relative mass uncertainties of 2x10-8 and better have been achieved. The accurate mass determination of 35K (dm=0.54keV) has been exploited to test the Isobaric Multiplet Mass Equation (IMME) for the A=35, T=3/2 isospinquartet. The experimental results indicate a deviation from the generally adopted quadratic form.
[ { "version": "v1", "created": "Sat, 21 Jul 2007 09:44:53 GMT" } ]
2008-11-26T00:00:00
[ [ "Yazidjian", "C.", "" ], [ "Audi", "G.", "" ], [ "Beck", "D.", "" ], [ "Blaum", "K.", "" ], [ "George", "S.", "" ], [ "Guenaut", "C.", "" ], [ "Herfurth", "F.", "" ], [ "Herlert", "A.", "" ], [ "Kellerbauer", "A.", "" ], [ "Kluge", "H. -J.", "" ], [ "Lunney", "D.", "" ], [ "Schweikhard", "L.", "" ] ]
0707.3202
Wolfgang Lucha
Z.-F. Li, Wolfgang Lucha, F. Schoberl
Stability in the instantaneous Bethe-Salpeter formalism: harmonic-oscillator reduced Salpeter equation
23 pages, 3 figures, extended conclusions, version to appear in Phys. Rev. D
Phys.Rev.D76:125028,2007
10.1103/PhysRevD.76.125028
HEPHY-PUB 843/07
hep-ph nucl-th
null
A popular three-dimensional reduction of the Bethe-Salpeter formalism for the description of bound states in quantum field theory is the Salpeter equation, derived by assuming both instantaneous interactions and free propagation of all bound-state constituents. Numerical (variational) studies of the Salpeter equation with confining interaction, however, observed specific instabilities of the solutions, likely related to the Klein paradox and rendering (part of the) bound states unstable. An analytic investigation of this problem by a comprehensive spectral analysis is feasible for the reduced Salpeter equation with only harmonic-oscillator confining interactions. There we are able to prove rigorously that the bound-state solutions correspond to real discrete energy spectra bounded from below and are thus free of any instabilities.
[ { "version": "v1", "created": "Mon, 23 Jul 2007 06:22:25 GMT" }, { "version": "v2", "created": "Fri, 9 Nov 2007 09:52:01 GMT" } ]
2008-11-26T00:00:00
[ [ "Li", "Z. -F.", "" ], [ "Lucha", "Wolfgang", "" ], [ "Schoberl", "F.", "" ] ]
0707.3203
Marcello Lissia
Gianni Fiorentini, Marcello Lissia, Fabio Mantovani
Geo-neutrinos and Earth's interior
56 pages in RMP ReVTeX format, 36 figures. A few typos corrected and a few minor points changed: resubmitted only to match the final version accepted for publication by Physics Reports
Phys.Rept.453:117-172,2007
10.1016/j.physrep.2007.09.001
null
physics.geo-ph astro-ph hep-ph nucl-ex nucl-th
null
The deepest hole that has ever been dug is about 12 km deep. Geochemists analyze samples from the Earth's crust and from the top of the mantle. Seismology can reconstruct the density profile throughout all Earth, but not its composition. In this respect, our planet is mainly unexplored. Geo-neutrinos, the antineutrinos from the progenies of U, Th and K40 decays in the Earth, bring to the surface information from the whole planet, concerning its content of natural radioactive elements. Their detection can shed light on the sources of the terrestrial heat flow, on the present composition, and on the origins of the Earth. Geo-neutrinos represent a new probe of our planet, which can be exploited as a consequence of two fundamental advances that occurred in the last few years: the development of extremely low background neutrino detectors and the progress on understanding neutrino propagation. We review the status and the prospects of the field.
[ { "version": "v1", "created": "Mon, 23 Jul 2007 13:51:47 GMT" }, { "version": "v2", "created": "Sat, 18 Aug 2007 13:52:57 GMT" } ]
2008-11-26T00:00:00
[ [ "Fiorentini", "Gianni", "" ], [ "Lissia", "Marcello", "" ], [ "Mantovani", "Fabio", "" ] ]
0707.3204
Charanjit S. Aulakh
Charanjit S. Aulakh
Emergence of the NMSGUT
Plenary talk at IWTHEP, Roorkee, India, March 15-20, 2007. Three .eps figures, one table
AIP Conf.Proc.939:31-39,2007
10.1063/1.2803783
null
hep-ph
null
We trace the emergence of the ``New Minimal'' supersymmetric SO(10) GUT (NMSGUT) out of the debris created by our demonstration that the MSGUT is falsified by the data. The NMSGUT is based on ${\bf{210\oplus 10\oplus 120\oplus 126\oplus {\bar {126}}}}$ Higgs system. It has only spontaneous CP violation and Type I seesaw. With only 24 real superpotential parameters it is the simplest model capable of accommodating the known 18 parameter fermion mass data set and yet has enough freedom to accommodate the still unknown Leptonic CP violation and neutrino mass scale parameters. Our focus is on the two most salient features uncovered by our analysis: the domination of the ${\bf{\bar{126}}}$ Yukawa couplings by those of the ${\bf{10,120}}$ (required for evasion of the no-go that trapped the MSGUT) and the inescapable raising of the Baryon violation scales(and thus suppression of proton decay) decreed by a proper inclusion of the threshold effects associated with the calculated superheavy spectra. These two structural features are shown to be complementary.
[ { "version": "v1", "created": "Sat, 21 Jul 2007 14:22:47 GMT" } ]
2011-02-09T00:00:00
[ [ "Aulakh", "Charanjit S.", "" ] ]
0707.3205
Andrew Schumann
Andrew Schumann, Florentin Smarandache
Neutrality and Many-Valued Logics
119 pages
A. Schumann, F. Smarandache, Neutrality and Many-Valued Logics. American Research Press, 2007
null
null
cs.LO cs.AI
null
In this book, we consider various many-valued logics: standard, linear, hyperbolic, parabolic, non-Archimedean, p-adic, interval, neutrosophic, etc. We survey also results which show the tree different proof-theoretic frameworks for many-valued logics, e.g. frameworks of the following deductive calculi: Hilbert's style, sequent, and hypersequent. We present a general way that allows to construct systematically analytic calculi for a large family of non-Archimedean many-valued logics: hyperrational-valued, hyperreal-valued, and p-adic valued logics characterized by a special format of semantics with an appropriate rejection of Archimedes' axiom. These logics are built as different extensions of standard many-valued logics (namely, Lukasiewicz's, Goedel's, Product, and Post's logics). The informal sense of Archimedes' axiom is that anything can be measured by a ruler. Also logical multiple-validity without Archimedes' axiom consists in that the set of truth values is infinite and it is not well-founded and well-ordered. On the base of non-Archimedean valued logics, we construct non-Archimedean valued interval neutrosophic logic INL by which we can describe neutrality phenomena.
[ { "version": "v1", "created": "Sat, 21 Jul 2007 10:35:37 GMT" } ]
2007-07-24T00:00:00
[ [ "Schumann", "Andrew", "" ], [ "Smarandache", "Florentin", "" ] ]
0707.3206
Horacio Wio
Sergio E. Mangioni (UNMdP, Argentina) and Horacio S. Wio (IFCA, Spain)
A random walker on a ratchet potential: Effect of a non Gaussian noise
Submitted to Europ.Phys. J. B (LaTex, 16 pgs, 8 figures)
null
10.1140/epjb/e2008-00027-y
null
cond-mat.stat-mech cond-mat.other
null
We analyze the effect of a colored non Gaussian noise on a model of a random walker moving along a ratchet potential. Such a model was motivated by the transport properties of motor proteins, like kinesin and myosin. Previous studies have been realized assuming white noises. However, for real situations, in general we could expect that those noises be correlated and non Gaussian. Among other aspects, in addition to a maximum in the current as the noise intensity is varied, we have also found another optimal value of the current when departing from Gaussian behavior. We show the relevant effects that arise when departing from Gaussian behavior, particularly related to current's enhancement, and discuss its relevance for both biological and technological situations.
[ { "version": "v1", "created": "Sat, 21 Jul 2007 10:46:23 GMT" }, { "version": "v2", "created": "Tue, 11 Dec 2007 17:59:07 GMT" } ]
2009-11-13T00:00:00
[ [ "Mangioni", "Sergio E.", "", "UNMdP, Argentina" ], [ "Wio", "Horacio S.", "", "IFCA, Spain" ] ]
0707.3207
Charlotte Wahl
Charlotte Wahl
Index theory for actions of compact Lie groups on C*-algebras
22 pages; sign corrections in section 4 and 5
null
null
null
math.KT math.OA
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study the index theory for actions of compact Lie groups on C*-algebras with an emphasis on principal actions. Given an invariant semifinite trace on the C*-algebra we obtain semifinite spectral triples. For circle actions we consider the relation to the dual Pimsner-Voiculescu sequence. On the way we show that the notions ``saturated'' and ``principal'' are equivalent for actions by compact Lie groups.
[ { "version": "v1", "created": "Sat, 21 Jul 2007 12:24:44 GMT" }, { "version": "v2", "created": "Sun, 4 Nov 2007 14:30:57 GMT" }, { "version": "v3", "created": "Sat, 28 Jun 2008 15:55:08 GMT" } ]
2008-06-28T00:00:00
[ [ "Wahl", "Charlotte", "" ] ]
0707.3208
Ronen Barak
R. Barak and Y. Ben-Aryeh
Amplification of gravitational waves signal in Michelson coherent-squeezed interferometer
5 pages, 2 figures
null
null
null
gr-qc
null
Gravitational waves reaching a Michelson interferometer are expected to induce a very small change in the length of its arms causing a phase shift between them, but it is very difficult to observe the extremely small phase shift signals produced. In the present letter we show that the gravitational waves signal could be amplified by orders of magnitude by using very special conditions for a coherent-squeezed Michelson interferometer in which the coherent state enters one port of the interferometer and the squeezed vacuum enters in the other port. We treat the case where without the gravitational induced phase shift the very strong coherent state goes out of one output port while the squeezed vacuum goes out the other output port (the ``dark'' port). While the phase shift produced by the gravitation waves does not give any significant change in the strong coherent output, the light intensity in the ``dark'' port is amplified with decreased fluctuations as the squeezing increases.
[ { "version": "v1", "created": "Sun, 22 Jul 2007 14:56:11 GMT" } ]
2007-07-24T00:00:00
[ [ "Barak", "R.", "" ], [ "Ben-Aryeh", "Y.", "" ] ]
0707.3209
Rafael Molina A
Rafael A. Molina, Jorge Dukelsky, Peter Schmitteckert
Commensurability effects for fermionic atoms trapped in 1D optical lattices
Accepted for publication in Physical Review Letters
Phys. Rev. Lett. 99, 080404 (2007)
10.1103/PhysRevLett.99.080404
null
cond-mat.str-el
null
Fermionic atoms in two different hyperfine states confined in optical lattices show strong commensurability effects due to the interplay between the atomic density wave (ADW) ordering and the lattice potential. We show that spatially separated regions of commensurable and incommensurable phases can coexist. The commensurability between the harmonic trap and the lattice sites can be used to control the amplitude of the atomic density waves in the central region of the trap.
[ { "version": "v1", "created": "Mon, 23 Jul 2007 14:50:57 GMT" } ]
2009-11-13T00:00:00
[ [ "Molina", "Rafael A.", "" ], [ "Dukelsky", "Jorge", "" ], [ "Schmitteckert", "Peter", "" ] ]
0707.3210
Mariano Suarez-Alvarez
Mariano Su\'arez-Alvarez
Applications of the change-of-rings spectral sequence to the computation of Hochschild cohomology
27 pages, 3 figures
null
null
null
math.KT
null
We consider the change-of-rings spectral sequence as it applies to Hochschild cohomology, obtaining a description of the differentials on the first page which relates it to the multiplicative stucture on cohomology. Using this information, we are able to completely describe the cohomology structure of monogenic algebras as well as some information on the structure of the cohomology in more general situations. We also show how to use the spectral sequence to reprove and generalize results of M. Auslander et. al. about homological epimorphisms. We derive from this a rather general version of the long exact sequence due to D. Happel for a one-point (co)-extension of a finite dimensional algebra and show how it can be put to use in concrete examples.
[ { "version": "v1", "created": "Sat, 21 Jul 2007 13:48:03 GMT" } ]
2007-07-24T00:00:00
[ [ "Suárez-Alvarez", "Mariano", "" ] ]
0707.3211
Simone Calogero
Simone Calogero, Oscar Sanchez, Juan Soler
Asymptotic behavior and orbital stability of galactic dynamics in relativistic scalar gravity
30 pages, 3 figures
null
10.1007/s00205-008-0173-x
null
math-ph math.MP
null
The Nordstr\"om-Vlasov system is a relativistic Lorentz invariant generalization of the Vlasov-Poisson system in the gravitational case. The asymptotic behavior of solutions and the non-linear stability of steady states are investigated. It is shown that solutions of the Nordstr\"om-Vlasov system with energy grater or equal to the mass satisfy a dispersion estimate in terms of the conformal energy. When the energy is smaller than the mass, we prove existence and non-linear (orbital) stability of a class of static solutions (isotropic polytropes) against general perturbations. The proof of orbital stability is based on a variational problem associated to the minimization of the energy functional under suitable constraints.
[ { "version": "v1", "created": "Sat, 21 Jul 2007 13:49:19 GMT" } ]
2009-11-13T00:00:00
[ [ "Calogero", "Simone", "" ], [ "Sanchez", "Oscar", "" ], [ "Soler", "Juan", "" ] ]
0707.3212
Matthias Braun
Matthias Braun, Luca Chirolli, and Guido Burkard
Signature of chirality in scanning-probe imaging of charge flow in graphene
5 pages, 4 figures, added references, corrected typos
Phys. Rev. B 77, 115433 (2008)
10.1103/PhysRevB.77.115433
null
cond-mat.mes-hall
null
We theoretically propose to directly observe the chiral nature of charge carriers in graphene mono- and bilayers within a controlled scattering experiment. The charge located on a capacitively coupled scanning probe microscope (SPM) tip acts as a scattering center with controllable position on the graphene sheet. Unambiguous features from the chirality of the particles in single and bilayer graphene arise in the ballistic transport in the presence of such a scattering center. To theoretically model the scattering from the smooth potential created by the SPM tip, we develop the scattering formalism within first-order Born approximation. We calculate the current through a device with an SPM tip between two constrictions (quantum point contacts) as a function of the tip position.
[ { "version": "v1", "created": "Sat, 21 Jul 2007 14:03:52 GMT" }, { "version": "v2", "created": "Thu, 7 Feb 2008 12:37:10 GMT" } ]
2009-11-13T00:00:00
[ [ "Braun", "Matthias", "" ], [ "Chirolli", "Luca", "" ], [ "Burkard", "Guido", "" ] ]
0707.3213
Zhe-Yu Jeff Ou
Z. Y. Ou, B. H. Liu, F. W. Sun, Y. X. Gong, Y. F. Huang, and G. C. Guo
Demonstration of Temporal Distinguishability of Three and Four Photons with Asymmetric Beam Splitter
to be published in the proceedings of Coherence and Quantum Optics 9
null
null
null
quant-ph
null
By using an asymmetric beam splitter, we observe the generalized Hong-Ou-Mandel effects for three and four photons, respectively. Furthermore, we can use this generalized Hong-Ou-Mandel interferometer to characterize temporal distinguishability.
[ { "version": "v1", "created": "Sat, 21 Jul 2007 14:56:12 GMT" } ]
2007-07-24T00:00:00
[ [ "Ou", "Z. Y.", "" ], [ "Liu", "B. H.", "" ], [ "Sun", "F. W.", "" ], [ "Gong", "Y. X.", "" ], [ "Huang", "Y. F.", "" ], [ "Guo", "G. C.", "" ] ]
0707.3214
Ruixue Xu
Rui-Xue Xu, Ying Chen, Ping Cui, Hong-Wei Ke, and YiJing Yan
The quantum solvation, adiabatic versus nonadiabatic, and Markovian versus non-Markovian nature of electron transfer rate processes
13 pages, 10 figures, submitted to J. Phys. Chem. A
null
10.1021/jp074164e
null
physics.chem-ph
null
In this work, we revisit the electron transfer rate theory, with particular interests in the distinct quantum solvation effect, and the characterizations of adiabatic/nonadiabatic and Markovian/non-Markovian rate processes. We first present a full account for the quantum solvation effect on the electron transfer in Debye solvents, addressed previously in J. Theore. & Comput. Chem. {\bf 5}, 685 (2006). Distinct reaction mechanisms, including the quantum solvation-induced transitions from barrier-crossing to tunneling, and from barrierless to quantum barrier-crossing rate processes, are shown in the fast modulation or low viscosity regime. This regime is also found in favor of nonadiabatic rate processes. We further propose to use Kubo's motional narrowing line shape function to describe the Markovian character of the reaction. It is found that a non-Markovian rate process is most likely to occur in a symmetric system in the fast modulation regime, where the electron transfer is dominant by tunneling due to the Fermi resonance.
[ { "version": "v1", "created": "Sat, 21 Jul 2007 14:57:50 GMT" } ]
2016-09-28T00:00:00
[ [ "Xu", "Rui-Xue", "" ], [ "Chen", "Ying", "" ], [ "Cui", "Ping", "" ], [ "Ke", "Hong-Wei", "" ], [ "Yan", "YiJing", "" ] ]
0707.3215
Ting Yu
Ting Yu and J. H. Eberly
Many-Body Separability of Warm Qubits
4 pages, 2 figures
null
null
null
quant-ph cond-mat.stat-mech
null
We analyze the separability of the joint state of a collection of two-level systems at finite temperature T. The fact that only separable states are found in the neighborhood of their thermal equilibrium state guarantees that decoherence will destroy any initially arranged entanglement in a finite time.
[ { "version": "v1", "created": "Mon, 23 Jul 2007 13:48:57 GMT" } ]
2007-07-24T00:00:00
[ [ "Yu", "Ting", "" ], [ "Eberly", "J. H.", "" ] ]
0707.3216
Jack Morava
Jack Morava
Complex cobordism and algebraic topology
This is an attempt to supplement recent [BAMS 2004] accounts of Ren\'e Thom's work on cobordism theory with a description of that subject's later evolution -- in particular, its connection with the local Langlands program
null
null
null
math.HO math.KT
null
This is a historical survey, beginning where Atiyah and Sullivan leave off...
[ { "version": "v1", "created": "Sat, 21 Jul 2007 15:18:30 GMT" } ]
2007-07-24T00:00:00
[ [ "Morava", "Jack", "" ] ]
0707.3217
Victor Kaftal
Victor Kaftal (University of Cincinnati), Gary Weiss (University of Cincinnati)
Soft ideals and arithmetic mean ideals
21 pages
Int Eq Oper Theory (58), 3, (2007), 363-405
null
null
math.FA math.OA
null
This article investigates the soft-interior and the soft-cover of operator ideals. These operations, and especially the first one, have been widely used before, but making their role explicit and analyzing their interplay with the arithmetic mean operations is essential for the study of the multiplicity of traces (see arXiv:0707.3169v1 [math.FA]). Many classical ideals are "soft", i.e., coincide with their soft interior or with their soft cover, and many ideal constructions yield soft ideals. Arithmetic mean (am) operations were proven to be intrinsic to the theory of operator ideals by the work of Dykema, Figiel, Weiss, and Wodzicki on the structure of commutators and arithmetic mean operations at infinity were studied in arXiv:0707.3169v1 [math.FA]. Here we focus on the commutation relations between these operations and soft operations. In the process we characterize the am-interior and the am-infinity interior of an ideal.
[ { "version": "v1", "created": "Sat, 21 Jul 2007 16:15:30 GMT" } ]
2007-07-24T00:00:00
[ [ "Kaftal", "Victor", "", "University of Cincinnati" ], [ "Weiss", "Gary", "", "University of\n Cincinnati" ] ]
0707.3218
Ramin Skibba
Ramin A. Skibba (MPIA), Ravi K. Sheth, Matthew C. Martino (UPenn)
Satellite Luminosities in Galaxy Groups
8 pages, 3 figures. Matches version accepted by MNRAS
Mon.Not.Roy.Astron.Soc.382:1940-1946,2007
10.1111/j.1365-2966.2007.12504.x
null
astro-ph
null
Halo model interpretations of the luminosity dependence of galaxy clustering assume that there is a central galaxy in every sufficiently massive halo, and that this central galaxy is very different from all the others in the halo. The halo model decomposition makes the remarkable prediction that the mean luminosity of the non-central galaxies in a halo should be almost independent of halo mass: the predicted increase is about 20% while the halo mass increases by a factor of more than 20. In contrast, the luminosity of the central object is predicted to increase approximately linearly with halo mass at low to intermediate masses, and logarithmically at high masses. We show that this weak, almost non-existent mass-dependence of the satellites is in excellent agreement with the satellite population in group catalogs constructed by two different collaborations. This is remarkable, because the halo model prediction was made without ever identifying groups and clusters. The halo model also predicts that the number of satellites in a halo is drawn from a Poisson distribution with mean which depends on halo mass. This, combined with the weak dependence of satellite luminosity on halo mass, suggests that the Scott effect, such that the luminosities of very bright galaxies are merely the statistically extreme values of a general luminosity distribution, may better apply to the most luminous satellite galaxy in a halo than to BCGs. If galaxies are identified with halo substructure at the present time, then central galaxies should be about 4 times more massive than satellite galaxies of the same luminosity, whereas the differences between the stellar M/L ratios should be smaller. Therefore, a comparison of the weak lensing signal from central and satellite galaxies should provide useful constraints. [abridged]
[ { "version": "v1", "created": "Sat, 21 Jul 2007 16:51:40 GMT" }, { "version": "v2", "created": "Mon, 5 May 2008 13:05:44 GMT" } ]
2009-02-02T00:00:00
[ [ "Skibba", "Ramin A.", "", "MPIA" ], [ "Sheth", "Ravi K.", "", "UPenn" ], [ "Martino", "Matthew C.", "", "UPenn" ] ]
0707.3219
Krzysztof Urbanowski
K. Urbanowski, J. Jankiewicz; (University of Zielona Gora, Institute of Physics, Poland)
Unitarity and real properties of the neutral meson complex
LaTeX2e, 24 pages, 3 figures, typos corrected
null
null
null
hep-ph
null
The proof of the Khalfin Theorem for neutral meson complex is analyzed. It is shown that the unitarity of the time evolution operator for the total system under considerations assures that the Khalfin's Theorem holds. The consequences of this Theorem for the neutral mesons system are discussed: it is shown, eg., that diagonal matrix elements of the exact effective Hamiltonian for the neutral meson complex can not be equal if CPT symmetry holds and CP symmetry is violated. Properties of time evolution governed by a time--independent effective Hamiltonian acting in the neutral mesons subspace of states are considered. Using the Khalfin's Theorem it is shown that if such Hamiltonian is time--independent then the evolution operator for the total system containing the neutral meson complex can not be a unitary operator. It is shown graphically for a given specific model how the Khalfin's Theorem works. It is also shown for this model how the difference of the mentioned diagonal matrix elements of the effective Hamiltonian varies in time.
[ { "version": "v1", "created": "Sat, 21 Jul 2007 17:58:42 GMT" }, { "version": "v2", "created": "Sun, 9 Dec 2007 19:49:15 GMT" } ]
2007-12-09T00:00:00
[ [ "Urbanowski", "K.", "", "University of Zielona Gora, Institute\n of Physics, Poland" ], [ "Jankiewicz;", "J.", "", "University of Zielona Gora, Institute\n of Physics, Poland" ] ]
0707.3220
Joseph Bennett
Joseph W. Bennett, Ram Seshadri, Susannah L. Scott, Andrew M. Rappe
First-principles modeling of BaCeO_{3}: structure and stabilization of O vacancies by Pd-doping
6 pages, 4 tables and 6 figures
null
null
null
cond-mat.mtrl-sci
null
We use first-principles density functional theory (DFT) calculations to investigate the ground state structures of both BaCeO_{3} (BC) and Pd-doped BC (BCP). The relaxed structures match closely with recent experimental scattering studies, and also provide a local picture of how the BC perovskite lattice accommodates Pd. Both stoichiometric and oxygen-deficient materials are considered, and structures with an O vacancy adjacent to each Pd are predicted to be favored. The oxidation state of Pd in each doped structure is investigated through a structural analysis, the results of which are supported by an orbital-resolved projected density of states. The vacancy stabilization by Pd in BCP is explained through redox chemistry and lattice strain relief.
[ { "version": "v1", "created": "Sat, 21 Jul 2007 17:58:47 GMT" } ]
2007-07-24T00:00:00
[ [ "Bennett", "Joseph W.", "" ], [ "Seshadri", "Ram", "" ], [ "Scott", "Susannah L.", "" ], [ "Rappe", "Andrew M.", "" ] ]
0707.3221
David Kleinhans
D. Kleinhans, R. Friedrich
Continuous Time Random Walks (CTRWs): Simulation of continuous trajectories
7 pages, 7 figures
null
10.1103/PhysRevE.76.061102
null
physics.data-an physics.chem-ph
null
Continuous time random walks have been developed as a straightforward generalisation of classical random walk processes. Some 10 years ago, Fogedby introduced a continuous representation of these processes by means of a set of Langevin equations [H. C. Fogedby, Phys. Rev. E 50 (1994)]. The present work is devoted to a detailed discussion of Fogedby's model and presents its application for the robust numerical generation of sample paths of continuous time random walk processes.
[ { "version": "v1", "created": "Sat, 21 Jul 2007 17:59:30 GMT" }, { "version": "v2", "created": "Thu, 18 Oct 2007 08:38:58 GMT" } ]
2009-11-13T00:00:00
[ [ "Kleinhans", "D.", "" ], [ "Friedrich", "R.", "" ] ]
0707.3222
Theodore A. Jacobson
Ted Jacobson
When is g_{tt} g_{rr} = -1?
3 pages; v2: references, and discussion of Born-Infeld solutions and O(3) and string hedgehogs added; 4 pages; v3: slight editing; comment added that condition implies radial pressure is negative of energy density; version to appear in CQG
Class.Quant.Grav.24:5717-5719,2007
10.1088/0264-9381/24/22/N02
null
gr-qc hep-th
null
The Schwarzschild metric, its Reissner-Nordstrom-de Sitter generalizations to higher dimensions, and some further generalizations all share the feature that g_{tt} g_{rr}=-1 in Schwarzschild-like coordinates. In this pedagogical note we trace this feature to the condition that the Ricci tensor (and stress-energy tensor in a solution to Einstein's equation) has vanishing radial null-null component, i.e. is proportional to the metric in the t-r subspace. We also show this condition holds if and only if the area-radius coordinate is an affine parameter on the radial null geodesics.
[ { "version": "v1", "created": "Sat, 21 Jul 2007 18:28:42 GMT" }, { "version": "v2", "created": "Mon, 17 Sep 2007 14:27:55 GMT" }, { "version": "v3", "created": "Fri, 28 Sep 2007 21:35:13 GMT" } ]
2008-11-26T00:00:00
[ [ "Jacobson", "Ted", "" ] ]
0707.3223
Nimesh Patel
J. M. Torrelles, N. A. Patel, S. Curiel, P. T. P. Ho, G. Garay, L. F. Rodriguez
The Circumstellar Structure and Excitation Effects around the Massive Protostar Cepheus A HW 2
12 pages, 3 figures; accepted for publication in the Astrophysical Journal
null
10.1086/521675
null
astro-ph
null
We report SMA 335 GHz continuum observations with angular resolution of ~0.''3, together with VLA ammonia observations with ~1'' resolution toward Cep A HW 2. We find that the flattened disk structure of the dust emission observed by Patel et al. is preserved at the 0.''3 scale, showing an elongated structure of ~$0.''6 size (450 AU) peaking on HW 2. In addition, two ammonia cores are observed, one associated with a hot-core previously reported, and an elongated core with a double peak separated by ~1.''3 and with signs of heating at the inner edges of the gas facing HW 2. The double-peaked ammonia structure, as well as the double-peaked CH3CN structure reported previously (and proposed to be two independent hot-cores), surround both the dust emission as well as the double-peaked SO2 disk structure found by Jimenez-Serra et al. All these results argue against the interpretation of the elongated dust-gas structure as due to a chance-superposition of different cores; instead, they imply that it is physically related to the central massive object within a disk-protostar-jet system.
[ { "version": "v1", "created": "Sat, 21 Jul 2007 18:52:27 GMT" } ]
2009-11-13T00:00:00
[ [ "Torrelles", "J. M.", "" ], [ "Patel", "N. A.", "" ], [ "Curiel", "S.", "" ], [ "Ho", "P. T. P.", "" ], [ "Garay", "G.", "" ], [ "Rodriguez", "L. F.", "" ] ]
0707.3224
Rudolf A. Roemer
G. Cuniberti, E. Macia, A. Rodriguez, R. A. R\"omer
Tight-binding modeling of charge migration in DNA devices
24 PDF pages of Springer SVMult LaTeX (included), ISBN-10: 3540724931, ISBN-13: 978-3540724933
in "Charge Migration in DNA: Perspectives from Physics, Chemistry and Biology" (T. Chakraborty, Ed.), Springer Verlag, Berlin, pp. 1-21 (2007), ISBN: 978-3-540-72493-3
10.1007/978-3-540-72494-0_1
null
q-bio.GN cond-mat.soft q-bio.OT
null
Long range charge transfer experiments in DNA oligomers and the subsequently measured -- and very diverse -- transport response of DNA wires in solid state experiments exemplifies the need for a thorough theoretical understanding of charge migration in DNA-based natural and artificial materials. Here we present a review of tight-binding models for DNA conduction which have the intrinsic merit of containing more structural information than plain rate-equation models while still retaining sufficient detail of the electronic properties. This allows for simulations of transport properties to be more manageable with respect to density functional theory methods or correlated first principle algorithms.
[ { "version": "v1", "created": "Sat, 21 Jul 2007 19:53:08 GMT" } ]
2015-05-13T00:00:00
[ [ "Cuniberti", "G.", "" ], [ "Macia", "E.", "" ], [ "Rodriguez", "A.", "" ], [ "Römer", "R. A.", "" ] ]
0707.3225
Harvey B. Meyer
Harvey B. Meyer, John W. Negele
Gluon contributions to the pion mass and light cone momentum fraction
4 pages, 2 figures
Phys.Rev.D77:037501,2008
10.1103/PhysRevD.77.037501
MIT-CTP 3840
hep-lat hep-ph
null
We calculate the matrix elements of the gluonic contributions to the energy-momentum tensor for a pion of mass 600 < Mpi < 1100 MeV in quenched lattice QCD. We find that gluons contribute (37 +/- 8 +/- 12)% of the pion's light cone momentum. The bare matrix elements corresponding to the trace anomaly contribution to the pion mass are also obtained. The discretizations of the energy-momentum tensor we use have other promising applications, ranging from calculating the origin of hadron spin to QCD thermodynamics.
[ { "version": "v1", "created": "Sat, 21 Jul 2007 20:40:05 GMT" } ]
2008-11-26T00:00:00
[ [ "Meyer", "Harvey B.", "" ], [ "Negele", "John W.", "" ] ]
0707.3226
Gennaro Amendola
Gennaro Amendola
Invariants of Closed 3-Manifolds via Nullhomotopic Filling Dehn Spheres
33 pages, 38 figures; added two open questions in Section 3; corrected Figure 11
Algebr. Geom. Topol. 9 (2009), no. 2, 903-933
10.2140/agt.2009.9.903
null
math.GT
null
We provide a calculus for the presentation of closed 3-manifolds via nullhomotopic filling Dehn spheres and we use it to define an invariant of closed 3-manifolds by applying the state-sum machinery. As a potential application of this invariant, we show how to get lower bounds for the Matveev complexity of P2-irreducible closed 3-manifolds. We also describe an easy algorithm for constructing a nullhomotopic filling Dehn sphere of each closed 3-manifold from any of its one-vertex triangulations.
[ { "version": "v1", "created": "Sat, 21 Jul 2007 20:20:11 GMT" }, { "version": "v2", "created": "Mon, 8 Oct 2007 20:25:39 GMT" }, { "version": "v3", "created": "Sat, 13 Oct 2007 14:52:16 GMT" } ]
2019-01-30T00:00:00
[ [ "Amendola", "Gennaro", "" ] ]
0707.3227
Stephen Sontz
Carlos Ernesto Angulo Aguila, Stephen Bruce Sontz
Direct and reverse log-Sobolev inequalities in $\mu$-deformed Segal-Bargmann analysis
Accepted for publication in Infinite Dimensional Analysis, Quantum Probability and Related Topics
null
null
null
math-ph math.MP
null
Both direct and reverse log-Sobolev inequalities, relating the Shannon entropy with a $\mu$-deformed energy, are shown to hold in a family of $\mu$-deformed Segal-Bargmann spaces. This shows that the $\mu$-deformed energy of a state is finite if and only if its Shannon entropy is finite. The direct inequality is a new result, while the reverse inequality has already been shown by the authors but using different methods. Next the $\mu$-deformed energy of a state is shown to be finite if and only if its Dirichlet form energy is finite. This leads to both direct and reverse log-Sobolev inequalities that relate the Shannon entropy with the Dirichlet energy. We obtain that the Dirichlet energy of a state is finite if and only if its Shannon entropy is finite. The main method used here is based on a study of the reproducing kernel function of these spaces and the associated integral kernel transform.
[ { "version": "v1", "created": "Sat, 21 Jul 2007 20:22:09 GMT" } ]
2007-07-24T00:00:00
[ [ "Aguila", "Carlos Ernesto Angulo", "" ], [ "Sontz", "Stephen Bruce", "" ] ]
0707.3228
Charles B. Thorn
Charles B. Thorn
1- Brane Sources for the Lightcone Worldsheet: Q-branion - {\bar Q}-branion Scattering to One Loop
26 pages, footnote clarifying T-dual action principle added, minor typos corrected, reference added
Phys.Rev.D76:106009,2007
10.1103/PhysRevD.76.106009
null
hep-th
null
This paper extends the study, initiated by Rozowsky and Thorn [1], of gauge fields in interaction with Dirac fields living on separated parallel 1-branes. In a lightcone description, replacing static point sources by 1-brane sources allows p^+ conservation to be maintained in their presence, which simplifies the lightcone quantization procedure. Here we calculate on-shell branion scattering amplitudes through 1 loop in lightcone gauge, and thereby resolve a puzzling ambiguity encountered in the off-shell calculations of [1]. We confirm that infrared divergences cancel in properly defined scattering probabilities. This work lays the groundwork for the incorporation of 1-brane sources in the lightcone worldsheet formalism.
[ { "version": "v1", "created": "Sun, 22 Jul 2007 20:49:56 GMT" }, { "version": "v2", "created": "Sat, 3 Nov 2007 20:39:28 GMT" } ]
2008-11-26T00:00:00
[ [ "Thorn", "Charles B.", "" ] ]
0707.3229
Marc A. Rieffel
Marc A. Rieffel (U. C. Berkeley)
Leibniz seminorms for "Matrix algebras converge to the sphere"
46 pages. Scattered very minor improvements
Quanta of maths, 543-578, Clay Math. Proc., 11, Amer. Math. Soc., Providence, RI, 2010
null
null
math.OA hep-th math.MG
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In an earlier paper of mine relating vector bundles and Gromov-Hausdorff distance for ordinary compact metric spaces, it was crucial that the Lipschitz seminorms from the metrics satisfy a strong Leibniz property. In the present paper, for the now non-commutative situation of matrix algebras converging to the sphere (or to other spaces) for quantum Gromov-Hausdorff distance, we show how to construct suitable seminorms that also satisfy the strong Leibniz property. This is in preparation for making precise certain statements in the literature of high-energy physics concerning "vector bundles" over matrix algebras that "correspond" to monopole bundles over the sphere. We show that a fairly general source of seminorms that satisfy the strong Leibniz property consists of derivations into normed bimodules. For matrix algebras our main technical tools are coherent states and Berezin symbols.
[ { "version": "v1", "created": "Sat, 21 Jul 2007 21:03:23 GMT" }, { "version": "v2", "created": "Thu, 27 Aug 2009 17:40:49 GMT" }, { "version": "v3", "created": "Fri, 8 Jan 2010 00:07:43 GMT" } ]
2011-12-13T00:00:00
[ [ "Rieffel", "Marc A.", "", "U. C. Berkeley" ] ]