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| versions
list | update_date
timestamp[s] | authors_parsed
sequence |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
0705.2498 | Dipten Bhattacharya | R. Mazumder, P.Sujatha Devi, Dipten Bhattacharya, P. Choudhury, A.
Sen, and M. Raja | Ferromagnetism in nanoscale BiFeO3 | 13 pages including 4 figures; pdf only; submitted to Appl. Phys. Lett | Appl. Phys. Lett. 91, 062510 (2007) | 10.1063/1.2768201 | null | cond-mat.mtrl-sci | null | A remarkably high saturation magnetization of ~0.4mu_B/Fe along with room
temperature ferromagnetic hysteresis loop has been observed in nanoscale (4-40
nm) multiferroic BiFeO_3 which in bulk form exhibits weak magnetization
(~0.02mu_B/Fe) and an antiferromagnetic order. The magnetic hysteresis loops,
however, exhibit exchange bias as well as vertical asymmetry which could be
because of spin pinning at the boundaries between ferromagnetic and
antiferromagnetic domains. Interestingly, like in bulk BiFeO_3, both the
calorimetric and dielectric permittivity data in nanoscale BiFeO_3 exhibit
characteristic features at the magnetic transition point. These features
establish formation of a true ferromagnetic-ferroelectric system with a
coupling between the respective order parameters in nanoscale BiFeO_3.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 08:48:40 GMT"
}
] | 2011-11-09T00:00:00 | [
[
"Mazumder",
"R.",
""
],
[
"Devi",
"P. Sujatha",
""
],
[
"Bhattacharya",
"Dipten",
""
],
[
"Choudhury",
"P.",
""
],
[
"Sen",
"A.",
""
],
[
"Raja",
"M.",
""
]
] |
0705.2499 | Xavier Blanc | Amandine Aftalion, Xavier Blanc, Robert L. Jerrard | Nonclassical rotational inertia for a supersolid under rotation | null | null | 10.1103/PhysRevLett.99.135301 | null | cond-mat.other | null | As proposed by Leggett [4], the supersolidity of a crystal is characterized
by the Non Classical Rotational Inertia (NCRI) property. Using a model of
quantum crystal introduced by Josserand, Pomeau and Rica [5], we prove that
NCRI occurs. This is done by analyzing the ground state of the aforementioned
model, which is related to a sphere packing problem, and then deriving a
theoretical formula for the inertia momentum. We infer a lower estimate for the
NCRI fraction, which is a landmark of supersolidity.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 09:16:24 GMT"
},
{
"version": "v2",
"created": "Tue, 17 Jul 2007 08:23:17 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Aftalion",
"Amandine",
""
],
[
"Blanc",
"Xavier",
""
],
[
"Jerrard",
"Robert L.",
""
]
] |
0705.2500 | Hamid Reza Sepangi | M Neek-Amal, H. Rafii-Tabar and H. R. Sepangi | Enhanced roughness of lipid membranes caused by external electric fields | 9 pages, 6 figures, to appear in Computational Materials Science | Comp. Mat. Sci. 41 (2007) 202--207 | null | null | cond-mat.soft | null | The behavior of lipid membranes in the presence of an external electric field
is studied and used to examine the influence of such fields on membrane
parameters such as roughness and show that for a micro sized membrane,
roughness grows as the field increases. The dependence of bending rigidity on
the electric field is also studied and an estimation of thickness of the
accumulated charges around lipid membranes in a free-salt solution is
presented.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 09:21:12 GMT"
}
] | 2007-11-12T00:00:00 | [
[
"Neek-Amal",
"M",
""
],
[
"Rafii-Tabar",
"H.",
""
],
[
"Sepangi",
"H. R.",
""
]
] |
0705.2501 | Francis Bernardeau | Francis Bernardeau and Tristan Brunier (SPhT Saclay) | Non-Gaussianities in extended D-term inflation | 12 pages, 7 figures, submitted to Phys. Rev. D | Phys.Rev.D76:043526,2007 | 10.1103/PhysRevD.76.043526 | Saclay T07/005 | hep-ph astro-ph | null | We explore extensions of hybrid inflationary models in the context of
supersymmetric D-term inflation. We point out that a large variety of
inflationary scenarios can be encountered when the field content is extended.
It is not only possible to get curvaton type models but also scenarios in which
different fields, with nontrivial statistical properties, contribute to the
primordial curvature fluctuations. We explore more particularly the parameter
space of these multiple field inflationary models. It is shown that there
exists a large domain in which significant primordial non-Gaussianities can be
produced while preserving a scale free power spectrum for the metric
fluctuations. In particular we explicitly compute the expected bi- and
trispectrum for such models and compared the results to the current and
expected observational constraints. It is shown that it is necessary to use
both the bi- and tri-spectra of CMB anisotropies to efficiently reduce their
parameter space.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 09:25:09 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Bernardeau",
"Francis",
"",
"SPhT Saclay"
],
[
"Brunier",
"Tristan",
"",
"SPhT Saclay"
]
] |
0705.2502 | David G. Cerdeno | G. Bertone, D.G. Cerdeno, J.I. Collar, B. Odom | WIMP identification through a combined measurement of axial and scalar
couplings | 4 pages 2 figures, uses revtex. References added and Fig.2 improved.
To appear in PRL | Phys.Rev.Lett.99:151301,2007 | 10.1103/PhysRevLett.99.151301 | FTUAM 07/08, IFT-UAM/CSIC-07-20 | astro-ph hep-ph | null | We study the prospects for detecting Weakly Interacting Massive Particles
(WIMPs), in a number of phenomenological scenarios, with a detector composed of
a target simultaneously sensitive to both spin-dependent and spin-independent
couplings, as is the case of COUPP (Chicagoland Observatory for Underground
Particle Physics). First, we show that sensitivity to both couplings optimizes
chances of initial WIMP detection. Second, we demonstrate that in case of
detection, comparison of the signal on two complementary targets, such as in
COUPP CF3I and C4F10 bubble chambers, allows a significantly more precise
determination of the dark matter axial and scalar couplings. This strategy
would provide crucial information on the nature of the WIMPs, and possibly
allow discrimination between neutralino and Kaluza-Klein dark matter.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 09:26:04 GMT"
},
{
"version": "v2",
"created": "Mon, 23 Jul 2007 14:33:38 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Bertone",
"G.",
""
],
[
"Cerdeno",
"D. G.",
""
],
[
"Collar",
"J. I.",
""
],
[
"Odom",
"B.",
""
]
] |
0705.2503 | Peng Cui | Peng Cui | Improved Approximability Result for Test Set with Small Redundancy | 7 pages | null | null | null | cs.DS cs.CC | null | Test set with redundancy is one of the focuses in recent bioinformatics
research. Set cover greedy algorithm (SGA for short) is a commonly used
algorithm for test set with redundancy. This paper proves that the
approximation ratio of SGA can be $(2-\frac{1}{2r})\ln n+{3/2}\ln r+O(\ln\ln
n)$ by using the potential function technique. This result is better than the
approximation ratio $2\ln n$ which directly derives from set multicover, when
$r=o(\frac{\ln n}{\ln\ln n})$, and is an extension of the approximability
results for plain test set.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 09:53:20 GMT"
},
{
"version": "v2",
"created": "Thu, 7 Jun 2007 09:11:18 GMT"
},
{
"version": "v3",
"created": "Tue, 11 Sep 2007 09:21:21 GMT"
},
{
"version": "v4",
"created": "Thu, 27 Sep 2007 14:58:21 GMT"
}
] | 2007-09-27T00:00:00 | [
[
"Cui",
"Peng",
""
]
] |
0705.2504 | Yuichi Togashi | Yuichi Togashi, Alexander S. Mikhailov | Nonlinear Relaxation Dynamics in Elastic Networks and Design Principles
of Molecular Machines | 12 pages, 9 figures | Proc. Natl. Acad. Sci. (USA) 104, 8697 (2007) | 10.1073/pnas.0702950104 | null | q-bio.BM cond-mat.soft physics.chem-ph | null | Analyzing nonlinear conformational relaxation dynamics in elastic networks
corresponding to two classical motor proteins, we find that they respond by
well-defined internal mechanical motions to various initial deformations and
that these motions are robust against external perturbations. We show that this
behavior is not characteristic for random elastic networks. However, special
network architectures with such properties can be designed by evolutionary
optimization methods. Using them, an example of an artificial elastic network,
operating as a cyclic machine powered by ligand binding, is constructed.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 10:21:26 GMT"
}
] | 2007-06-13T00:00:00 | [
[
"Togashi",
"Yuichi",
""
],
[
"Mikhailov",
"Alexander S.",
""
]
] |
0705.2505 | Sylvie Vauclair | M. Soriano, S. Vauclair, C. Vauclair, M. Laymand | The CoRoT primary target HD 52265: models and seismic tests | 11 pages, 7 figures, to be published in Astronomy and Astrophysics | null | 10.1051/0004-6361:20066798 | null | astro-ph | null | HD 52265 is the only known exoplanet-host star selected as a main target for
the seismology programme of the CoRoT satellite. As such, it will be observed
continuously during five months, which is of particular interest in the
framework of planetary systems studies. This star was misclassified as a giant
in the Bright Star Catalog, while it is more probably on the main-sequence or
at the beginning of the subgiant branch. We performed an extensive analysis of
this star, showing how asteroseismology may lead to a precise determination of
its external parameters and internal structure. We first reviewed the
observational constraints on the metallicity, the gravity and the effective
temperature derived from the spectroscopic observations of HD 52265. We also
derived its luminosity using the Hipparcos parallax. We computed the
evolutionary tracks for models of various metallicities which cross the
relevant observational error boxes in the gravity-effective temperature plane.
We selected eight different stellar models which satisfy the observational
constraints, computed their p-modes frequencies and analysed specific seismic
tests. The possible models for HD 52265, which satisfy the constraints derived
from the spectroscopic observations, are different in both their external and
internal parameters. They lie either on the main sequence or at the beginning
of the subgiant branch. The differences in the models lead to quite different
properties of their oscillation frequencies. We give evidences of an
interesting specific behaviour of these frequencies in case of helium-rich
cores: the ``small separations'' may become negative and give constraints on
the size of the core. We expect that the observations of this star by the CoRoT
satellite wi ll allow choosing between these possible models.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 09:35:46 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Soriano",
"M.",
""
],
[
"Vauclair",
"S.",
""
],
[
"Vauclair",
"C.",
""
],
[
"Laymand",
"M.",
""
]
] |
0705.2506 | Alexander Golubov | Y. Tanaka, Y. Tanuma, and A.A. Golubov | Odd-frequency pairing in normal metal/superconductor junctions | 27 pages, 12 figures | null | 10.1103/PhysRevB.76.054522 | null | cond-mat.supr-con cond-mat.str-el | null | We study the induced odd-frequency pairing states in ballistic normal
metal/superconductor (N/S) junctions where a superconductor has even-frequency
symmetry in the bulk and a normal metal layer has an arbitrary length. Using
the quasiclassical Green's function formalism, we demonstrate that, quite
generally, the pair amplitude in the junction has an admixture of an
odd-frequency component due to the breakdown of translational invariance near
the N/S interface where the pair potential acquires spatial dependence. If a
superconductor has even-parity pair potential (spin-singlet s-wave state), the
odd-frequency pairing component with odd-parity is induced near the N/S
interface, while in the case of odd-parity pair potential (spin-triplet
$p_{x}$-wave or spin-singlet $d_{xy}$-wave) the odd-frequency component with
even-parity is generated. We show that in conventional s-wave junctions, the
amplitude of the odd-frequency pairing state is enhanced at energies
corresponding to the peaks in the local density of states (LDOS). In $p_x$- and
$d_{xy}$-wave junctions, the amplitude of the odd-frequency component on the S
side of the N/S interface is enhanced at zero energy where the midgap Andreev
resonant state (MARS) appears due to the sign change of the pair potential. The
odd-frequency component extends into the N region and exceeds the
even-frequency component at energies corresponding to the LDOS peak positions,
including the MARS.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 10:04:26 GMT"
},
{
"version": "v2",
"created": "Fri, 18 May 2007 08:50:29 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Tanaka",
"Y.",
""
],
[
"Tanuma",
"Y.",
""
],
[
"Golubov",
"A. A.",
""
]
] |
0705.2507 | Jun Zhang Dr. | Jun Zhang, S. K. Solanki, J. Woch, and Jingxiu Wang | The velocity structure of moving magnetic feature pairs around sunspots:
support for the U-loop model | Submitted to A&A | null | 10.1051/0004-6361:20077900 | null | astro-ph | null | Using data recorded by the Michelson Doppler Imager (MDI) instrument on the
Solar and Heliospheric Observatory (SOHO), we have traced 123 pairs of opposite
magnetic polarity moving magnetic features (MMFs) in three active regions NOAA
ARs 8375, 0330 and 9575. At the time of observation, AR 8375 was young, AR 0330
mature, and AR 9575 decaying. The vertical velocity indicates that the elements
of MMF pairs with polarity opposite to that of the sunspot support a downflow
of around 50-100 m s$^{-1}$. The average Doppler shift difference between
negative and positive elements of an MMF pair is about 150 m s$^{-1}$ in AR
8375, 100 m s$^{-1}$ in AR 0330, and 20 m s$^{-1}$ in AR 9575. These
observational results are in agreement with the model that MMF pairs are part
of a U-loop emanating from the sunspot's magnetic canopy. According to this
model the downflow is caused by the Evershed flow returning below the solar
surface. For AR 8375, the horizontal velocity of MMFs ranges from 0.1 km
s$^{-1}$ to 0.7 km s$^{-1}$, and on average, the velocity of an MMF pair
decreases significantly (from 0.6 km s$^{-1}$ to 0.35 km s$^{-1}$) with
increasing distance from the MMF's birth place. This result suggests that the
change in MMF flow speed does not reflect the radial structure of the moat
flow, but rather is intrinsic to the evolution of the MMF pairs. This result is
also in agreement with the U-loop model of MMF pairs. We also find that
properties of MMF pairs, most strikingly the lifetime, depend on the evolution
stages of the parent sunspot. The mean lifetimes of MMF pairs in ARs 9575 and
0330 are 0.7 hours and 1.6 hours, respectively, which is considerably shorter
than the 4 hours lifetime previously found for AR 8375.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 10:06:40 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Zhang",
"Jun",
""
],
[
"Solanki",
"S. K.",
""
],
[
"Woch",
"J.",
""
],
[
"Wang",
"Jingxiu",
""
]
] |
0705.2508 | Timo Bergmann | Timo Bergmann | Theorie des longitudinalen Atomstrahl-Spinechos und paritaetsverletzende
Berry-Phasen in Atomen | 264 pages, 59 figures, in german | null | null | null | physics.atom-ph | null | We present a nonrelativistic theory for the quantum mechanical description of
longitudinal atomic beam spin echo experiments, where a beam of neutral atoms
is subjected to static electric and magnetic fields. The atomic wave function
is the solution of a matrix-valued Schroedinger equation and can be written as
superposition of local (atomic) eigenstates of the potential matrix. The
position- and time-dependent amplitude function of each eigenstate represents
an atomic wave packet and can be calculated in a series expansion with a master
formula that we derive. The zeroth order of this series expansion describes the
adiabatic limit, whereas the higher order contributions contain the mixing of
the eigenstates and the corresponding amplitude functions.
We give a tutorial for the theoretical description of longitudinal atomic
beam spin echo experiments and for the so-called Fahrplan model, which is a
visualisation tool for the propagation of wave packets of different atomic
eigenstates.
As an example for the application of our theory, we study parity violating
geometric (Berry-)phases. In this context, we define geometric flux densities,
which for certain field configurations can be used to illustrate geometric
phases in a vector diagram. Considering an example with a specific field
configuration, we prove the existence of a parity violating geometric phase.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 10:34:40 GMT"
},
{
"version": "v2",
"created": "Fri, 18 May 2007 22:18:45 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Bergmann",
"Timo",
""
]
] |
0705.2509 | Lukasz Machura | L. Machura, M. Kostur, P. Talkner, P. Hanggi, and J. Luczka | Frequency Windows of Absolute Negative Conductance in Josephson
Junctions | 4 pages, 1 figure | null | 10.1063/1.2759719 | null | cond-mat.supr-con | null | We report on anomalous conductance in a resistively and capacitively shunted
Josephson junction which is simultaneously driven by ac and dc currents. The
dependence of the voltage across the junction on the frequency of the ac
current shows windows of absolute negative conductance regimes, i.e. for a
positive (negative) dc current, the voltage is negative (positive).
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 10:58:34 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Machura",
"L.",
""
],
[
"Kostur",
"M.",
""
],
[
"Talkner",
"P.",
""
],
[
"Hanggi",
"P.",
""
],
[
"Luczka",
"J.",
""
]
] |
0705.2510 | Daniele Dominici | R. Casalbuoni, S. De Curtis, D. Dominici and D. Dolce | Holographic approach to a minimal Higgsless model | Latex file, 23 pages | JHEP 0708:053,2007 | 10.1088/1126-6708/2007/08/053 | null | hep-ph hep-th | null | In this work, following an holographic approach, we carry out a low energy
effective study of a minimal Higgsless model based on SU(2) bulk symmetry
broken by boundary conditions, both in flat and warped metric. The holographic
procedure turns out to be an useful computation technique to achieve an
effective four dimensional formulation of the model taking into account the
corrections coming from the extra dimensional sector. This technique is used to
compute both oblique and direct contributions to the electroweak parameters in
presence of fermions delocalized along the fifth dimension.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 11:06:24 GMT"
}
] | 2009-04-21T00:00:00 | [
[
"Casalbuoni",
"R.",
""
],
[
"De Curtis",
"S.",
""
],
[
"Dominici",
"D.",
""
],
[
"Dolce",
"D.",
""
]
] |
0705.2511 | Helen Caines | STAR Collaboration: B.I. Abelev, et al | Enhanced strange baryon production in Au+Au collisions compared to p+p
at sqrts = 200 GeV | 7 pages, 4 figures. Printed in PRC | Phys.Rev.C77:044908,2008 | 10.1103/PhysRevC.77.044908 | null | nucl-ex | null | We report on the observed differences in production rates of strange and
multi-strange baryons in Au+Au collisions at sqrts = 200 GeV compared to pp
interactions at the same energy. The strange baryon yields in Au+Au collisions,
then scaled down by the number of participating nucleons, are enhanced relative
to those measured in pp reactions. The enhancement observed increases with the
strangeness content of the baryon, and increases for all strange baryons with
collision centrality. The enhancement is qualitatively similar to that observed
at lower collision energy sqrts =17.3 GeV. The previous observations are for
the bulk production, while at intermediate pT, 1 < pT< 4 GeV/c, the strange
baryons even exceed binary scaling from pp yields.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 11:14:19 GMT"
},
{
"version": "v2",
"created": "Mon, 2 Jun 2008 22:54:10 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"STAR Collaboration",
"",
""
],
[
"Abelev",
"B. I.",
""
]
] |
0705.2512 | Cesar R. de Oliveira | M. Cobo, C. Gutierrez, C. R. de Oliveira | Cantor Singular Continuous Spectrum for Operators Along Interval
Exchange Transformations | null | null | null | null | math-ph math.MP | null | It is shown that Schroedinger operators, with potentials along the shift
embedding of Lebesgue almost every interval exchange transformations, have
Cantor spectrum of measure zero and pure singular continuous for Lebesgue
almost all points of the interval.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 11:19:42 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Cobo",
"M.",
""
],
[
"Gutierrez",
"C.",
""
],
[
"de Oliveira",
"C. R.",
""
]
] |
0705.2513 | Tamas Unger | M. Reza Shaebani, Tamas Unger, Janos Kertesz | Unjamming of Granular Packings due to Local Perturbations: Stability and
Decay of Displacements | 4 pages, 4 figures | Phys. Rev. E 76, 030301(R) (2007) | 10.1103/PhysRevE.76.030301 | null | cond-mat.soft | null | We study the mechanical response generated by local deformations in jammed
packings of rigid disks. Based on discrete element simulations we determine the
critical force of the local perturbation that is needed to break the mechanical
equilibrium and examine the generated displacement field. Displacements decay
as a power law of the distance from the perturbation point. The decay exponent
and the critical force exhibit nontrivial dependence on the friction: Both
quantities are nonmonotonic and have a sharp maximum at the friction
coefficient 0.1. We find that the mechanical response properties are closely
related to the problem of force-indeterminacy where similar nonmonotonic
behavior was observed previously. We establish direct connection between the
critical force and the ensemble of static force networks.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 11:33:48 GMT"
},
{
"version": "v2",
"created": "Thu, 9 Aug 2007 14:22:49 GMT"
}
] | 2007-10-02T00:00:00 | [
[
"Shaebani",
"M. Reza",
""
],
[
"Unger",
"Tamas",
""
],
[
"Kertesz",
"Janos",
""
]
] |
0705.2514 | Mark Reynolds | Mark Reynolds, Paul Callanan, Andrew Fruchter, Manuel Torres, Martin
Beer and Rachel Gibbons | The light curve of the companion to PSR B1957+20 | 6 pages, 4 figures & 3tables. Accepted for publication in MNRAS | Mon.Not.Roy.Astron.Soc.379:1117-1122,2007 | 10.1111/j.1365-2966.2007.11991.x | null | astro-ph | null | We present a new analysis of the light curve for the secondary star in the
eclipsing binary millisecond pulsar system PSR B1957+20. Combining previous
data and new data points at minimum from the Hubble Space Telescope, we have
100% coverage in the R-band. We also have a number of new K_s-band data points,
which we use to constrain the infrared magnitude of the system. We model this
with the Eclipsing Light Curve code (ELC). From the modelling with the ELC code
we obtain colour information about the secondary at minimum light in BVRI and
K. For our best fit model we are able to constrain the system inclination to 65
+/- 2 degrees for pulsar masses ranging from 1.3 -- 1.9 M_sun. The pulsar mass
is unconstrained. We also find that the secondary star is not filling its Roche
lobe. The temperature of the un-irradiated side of the companion is in
agreement with previous estimates and we find that the observed temperature
gradient across the secondary star is physically sustainable.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 11:27:45 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"Reynolds",
"Mark",
""
],
[
"Callanan",
"Paul",
""
],
[
"Fruchter",
"Andrew",
""
],
[
"Torres",
"Manuel",
""
],
[
"Beer",
"Martin",
""
],
[
"Gibbons",
"Rachel",
""
]
] |
0705.2515 | Tshilidzi Marwala | Tshilidzi Marwala, Lungile Mdlazi and Sibusiso Sibisi | Finite Element Model Updating Using Bayesian Approach | 7 pages, IMAC2004 | null | null | null | stat.AP | null | This paper compares the Maximum-likelihood method and Bayesian method for
finite element model updating. The Maximum-likelihood method was implemented
using genetic algorithm while the Bayesian method was implemented using the
Markov Chain Monte Carlo. These methods were tested on a simple beam and an
unsymmetrical H-shaped structure. The results show that the Bayesian method
gave updated finite element models that predicted more accurate modal
properties than the updated finite element models obtained through the use of
the Maximum-likelihood method. Furthermore, both these methods were found to
require the same levels of computational loads.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 11:29:08 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Marwala",
"Tshilidzi",
""
],
[
"Mdlazi",
"Lungile",
""
],
[
"Sibisi",
"Sibusiso",
""
]
] |
0705.2516 | Tshilidzi Marwala | Sizwe M. Dhlamini*, Fulufhelo V. Nelwamondo**, Tshilidzi Marwala** | Condition Monitoring of HV Bushings in the Presence of Missing Data
Using Evolutionary Computing | 7 pages | null | null | null | cs.NE cs.AI | null | The work proposes the application of neural networks with particle swarm
optimisation (PSO) and genetic algorithms (GA) to compensate for missing data
in classifying high voltage bushings. The classification is done using DGA data
from 60966 bushings based on IEEEc57.104, IEC599 and IEEE production rates
methods for oil impregnated paper (OIP) bushings. PSO and GA were compared in
terms of accuracy and computational efficiency. Both GA and PSO simulations
were able to estimate missing data values to an average 95% accuracy when only
one variable was missing. However PSO rapidly deteriorated to 66% accuracy with
two variables missing simultaneously, compared to 84% for GA. The data
estimated using GA was found to classify the conditions of bushings than the
PSO.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 11:33:34 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Dhlamini*",
"Sizwe M.",
""
],
[
"Nelwamondo**",
"Fulufhelo V.",
""
],
[
"Marwala**",
"Tshilidzi",
""
]
] |
0705.2517 | Vincent Noel | Vincent Noel (LMD), Martial Haeffelin (LMD) | Midlatitude Cirrus Clouds and Multiple Tropopauses from a 2002-2006
Climatology over the SIRTA Observatory | null | Journal of Geophysical Research D: Atmospheres 112 (2007) D13206 | 10.1029/2006JD007753 | null | physics.ao-ph | null | This study present a comparison of lidar observations of midlatitude cirrus
clouds over the SIRTA observatory between 2002 and 2006 with multiple
tropopauses (MT) retrieved from radiosounding temperature profiles. The
temporal variability of MT properties (frequency, thickness) are discussed.
Results show a marked annual cycle, with MT frequency reaching its lowest point
in May (~18% occurrence of MT) and slowly rising to more than 40% in DJF. The
average thickness of the MT also follows an annual cycle, going from less than
1 km in spring to 1.5 km in late autumn. Comparison with lidar observations
show that cirrus clouds show a preference for being located close below the 1st
tropopause. When the cloud top is above the 1st tropopause (7% of
observations), in 20% of cases the cloud base is above it as well, resulting in
a cirrus cloud "sandwiched" between the two tropopauses. Compared to the
general distribution of cirrus, cross-tropopause cirrus show a higher frequency
of large optical depths, while inter-tropopause cirrus show almost exclusively
low optical depths (Tau < 0.03 in 90% of cases) typical of subvisible clouds.
Results suggest the occurrence of inter-tropopause cirrus clouds is correlated
with the frequency of multiple tropopauses.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 11:35:23 GMT"
}
] | 2008-03-05T00:00:00 | [
[
"Noel",
"Vincent",
"",
"LMD"
],
[
"Haeffelin",
"Martial",
"",
"LMD"
]
] |
0705.2518 | Nir Bar-Gill | Nir Bar-Gill, Eitan E. Rowen and Nir Davidson | Spectroscopy of Strong-Pulse Superradiance in a Bose-Einstein condensate | null | null | 10.1103/PhysRevA.76.043603 | null | cond-mat.other | null | We study experimentally superradiance in a Bose-Einstein condensate using a
two-frequency pump beam. By controlling the frequency difference between the
beam components, we measure the spectrum of the backward (energy-mismatched)
superradiant atomic modes. In addition, we show that the populations of these
modes display coherent time-dynamics. These results are compared to a
semi-classical model based on coupled Schroedinger-Maxwell equations.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 11:43:29 GMT"
},
{
"version": "v2",
"created": "Wed, 18 Jul 2007 18:30:13 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Bar-Gill",
"Nir",
""
],
[
"Rowen",
"Eitan E.",
""
],
[
"Davidson",
"Nir",
""
]
] |
0705.2519 | Alessandro Nagar | Thibault Damour, Alessandro Nagar | Faithful Effective-One-Body waveforms of small-mass-ratio coalescing
black-hole binaries | 13 pages, 6 figures. To appear in Phys. Rev. D | Phys.Rev.D76:064028,2007 | 10.1103/PhysRevD.76.064028 | null | gr-qc | null | We address the problem of constructing high-accuracy, faithful analytic
waveforms describing the gravitational wave signal emitted by inspiralling and
coalescing binary black holes. We work within the Effective-One-Body (EOB)
framework and propose a methodology for improving the current
(waveform)implementations of this framework based on understanding, element by
element, the physics behind each feature of the waveform, and on systematically
comparing various EOB-based waveforms with ``exact'' waveforms obtained by
numerical relativity approaches. The present paper focuses on small-mass-ratio
non-spinning binary systems, which can be conveniently studied by
Regge-Wheeler-Zerilli-type methods. Our results include: (i) a resummed,
3PN-accurate description of the inspiral waveform, (ii) a better description of
radiation reaction during the plunge, (iii) a refined analytic expression for
the plunge waveform, (iv) an improved treatment of the matching between the
plunge and ring-down waveforms. This improved implementation of the EOB
approach allows us to construct complete analytic waveforms which exhibit a
remarkable agreement with the ``exact'' ones in modulus, frequency and phase.
In particular, the analytic and numerical waveforms stay in phase, during the
whole process, within $\pm 1.1 %$ of a cycle. We expect that the extension of
our methodology to the comparable-mass case will be able to generate comparably
accurate analytic waveforms of direct use for the ground-based network of
interferometric detectors of gravitational waves.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 11:47:54 GMT"
},
{
"version": "v2",
"created": "Thu, 26 Jul 2007 15:33:55 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Damour",
"Thibault",
""
],
[
"Nagar",
"Alessandro",
""
]
] |
0705.2520 | Hideo Iguchi | Hideo Iguchi, Takashi Mishima, Shinya Tomizawa | Boosted Black Holes on Kaluza-Klein Bubbles | 17 pages, 1 figure | Phys.Rev.D76:124019,2007; Erratum-ibid.D78:109903,2008 | 10.1103/PhysRevD.76.124019 10.1103/PhysRevD.78.109903 | OCU-PHYS 268, AP-GR 44 | hep-th gr-qc | null | We construct an exact stationary solution of black hole -- bubble sequence in
the five dimensional Kaluza-Klein theory by using solitonic solution generating
techniques. The solution describes two boosted black holes with topology S^3 on
a Kaluza-Klein bubble and has a linear momentum component in the compactified
direction. The ADM mass and the linear momentum depend on the two boosted
velocity parameters of black holes. In the effective four dimensional theory,
the solution has an electric charge which is proportional to the linear
momentum. The solution includes the static solution found by Elvang and
Horowitz and a limit of single boosted black string.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 11:48:35 GMT"
}
] | 2014-11-18T00:00:00 | [
[
"Iguchi",
"Hideo",
""
],
[
"Mishima",
"Takashi",
""
],
[
"Tomizawa",
"Shinya",
""
]
] |
0705.2521 | Daniel Cavalcanti | D. Cavalcanti, M. O. Terra Cunha, A. Acin | Multipartite entanglement of superpositions | 4 pages. v2: reference added, text improved in clarity | Phys. Rev. A 76, 042329 (2007) | 10.1103/PhysRevA.76.042329 | null | quant-ph | null | The entanglement of superpositions [Phys. Rev. Lett. 97, 100502 (2006)] is
generalized to the multipartite scenario: an upper bound to the multipartite
entanglement of a superposition is given in terms of the entanglement of the
superposed states and the superposition coefficients. This bound is proven to
be tight for a class of states composed by an arbitrary number of qubits. We
also extend the result to a large family of quantifiers which includes the
negativity, the robustness of entanglement, and the best separable
approximation measure.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 12:28:21 GMT"
},
{
"version": "v2",
"created": "Tue, 22 May 2007 08:37:29 GMT"
}
] | 2007-10-24T00:00:00 | [
[
"Cavalcanti",
"D.",
""
],
[
"Cunha",
"M. O. Terra",
""
],
[
"Acin",
"A.",
""
]
] |
0705.2522 | Susanne Pumpluen | S. Pumpluen | Forms of higher degree permitting composition | 24 pages | null | null | null | math.RA | null | Nondegenerate forms N of degree d on a unital nonassociative algebra A over a
ring R which permit composition, i.e., satisfy N(1)=1 and N(xy)=N(x)N(y) for
all x,y in A, are studied. These forms were first classified by Schafer over
fields of characteristic 0 or >d. We investigate cubic and quartic
nondegenerate forms which permit composition over certain rings and curves.
Classes of highly degenerate cubic forms N over fields which permit composition
are constructed.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 12:55:04 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Pumpluen",
"S.",
""
]
] |
0705.2523 | Harshada Nagar | Srikanya Kundu, Harshada Nagar, S D Kulkarni, Renu Pasricha, A K Das,
G R Kulkarni and S V Bhoraskar | Applications of nanoparticles of gamma Fe2O3 for hyperthermia in E.coli
by Nd:YAG laser | 13 pages, 8 figures, communicated to Journal of Nanoparticle Research | null | null | null | physics.bio-ph | null | The paper explores the use of nanoparticles of gamma Fe2O3 for hyperthermia
treatment of living organisms by absorption of 1064 nm radiations from Nd:YAG
laser. Escherichia coli cells have been used as the model system for
demonstrating the effect wherein lysine is used as an interface between the
cell walls and the nanoparticles. Scanning Electron Microscopic observations
have, exclusively, proved that attachment of nanoparticles of iron oxide along
with lysine alone is responsible for absorption of above radiations. The
quantitative estimation has been provided by growth rate measurements and
protein assessment of the cells. The nanoparticles of gamma Fe2O3 were
synthesized by DC arc plasma assisted gas phase condensation.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 13:14:04 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Kundu",
"Srikanya",
""
],
[
"Nagar",
"Harshada",
""
],
[
"Kulkarni",
"S D",
""
],
[
"Pasricha",
"Renu",
""
],
[
"Das",
"A K",
""
],
[
"Kulkarni",
"G R",
""
],
[
"Bhoraskar",
"S V",
""
]
] |
0705.2524 | David Berge | D. Berge (for the H.E.S.S. Collaboration) | Observations of Galactic Gamma-Ray Sources with H.E.S.S | 13 pages, 10 figures, based on a talk presented at the workshop
'Energy Budget in the High Energy Universe', Kashiwa, Japan 22 - 24 February
2006 | null | 10.1142/9789812708342_0018 | null | astro-ph | null | H.E.S.S. results from the first three years of nominal operation are
presented. Among the many exciting measurements that have been made, most
gamma-ray sources are of Galactic origin. I will concentrate here on an
overview of Galactic observations and summarise and discuss observations of
selected objects of the different source types.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 07:47:16 GMT"
}
] | 2016-11-09T00:00:00 | [
[
"Berge",
"D.",
"",
"for the H.E.S.S. Collaboration"
]
] |
0705.2525 | Douglas A. Singleton | Emil T. Akhmedov and Douglas Singleton | On the physical meaning of the Unruh effect | 7 pages, 0 figures references added, small changes in text. To be
published JETP Letts | Pisma Zh.Eksp.Teor.Fiz.86:702-706,2007 | 10.1134/S0021364007210138 | null | hep-th gr-qc physics.acc-ph | null | We present simple arguments that detectors moving with constant acceleration
(even acceleration for a finite time) should detect particles. The effect is
seen to be universal. Moreover, detectors undergoing linear acceleration and
uniform, circular motion both detect particles for the same physical reason. We
show that if one uses a circularly orbiting electron in a constant external
magnetic field as the Unruh--DeWitt detector, then the Unruh effect physically
coincides with the experimentally verified Sokolov--Ternov effect.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 13:27:31 GMT"
},
{
"version": "v2",
"created": "Thu, 27 Sep 2007 01:39:07 GMT"
},
{
"version": "v3",
"created": "Fri, 19 Oct 2007 19:57:02 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Akhmedov",
"Emil T.",
""
],
[
"Singleton",
"Douglas",
""
]
] |
0705.2526 | Jarno Talponen | Jarno Talponen | Convex-transitive characterizations of Hilbert spaces | 23 pages | null | null | null | math.FA | null | In this paper we investigate real convex-transitive Banach spaces X, which
admit a 1-dimensional bicontractive projection P on X. Various mild conditions
regarding the weak topology and the geometry of the norm are provided, which
guarantee that such an X is in fact isometrically a Hilbert space. The results
obtained can be regarded as partial answers to the well-known Banach-Mazur
rotation problem, as well as to a question posed by B. Randrianantoanina in
2002 about convex-transitive spaces.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 13:29:15 GMT"
},
{
"version": "v2",
"created": "Fri, 18 May 2007 08:15:08 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Talponen",
"Jarno",
""
]
] |
0705.2527 | Piotr So{\l}tan | Piotr M. So{\l}tan, S. L. Woronowicz | From multiplicative unitaries to quantum groups II | 19 pages, LaTeX | J. Funct. Anal. 252 (1) (2007), 42-67 | null | null | math.OA | null | It is shown that all important features of a $\mathrm{C}^*$-algebraic quantum
group $(A,\Delta)$ defined by a modular multiplicative $W$ depend only on the
pair $(A,\Delta)$ rather than the multiplicative unitary operator $W$. The
proof is based on thorough study of representations of quantum groups. As an
application we present a construction and study properties of the universal
dual of a quantum group defined by a modular multiplicative unitary - without
assuming existence of Haar weights.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 13:34:21 GMT"
},
{
"version": "v2",
"created": "Tue, 17 Jul 2007 12:41:06 GMT"
}
] | 2011-04-12T00:00:00 | [
[
"Sołtan",
"Piotr M.",
""
],
[
"Woronowicz",
"S. L.",
""
]
] |
0705.2528 | Roberto de Propris | R. De Propris (CTIO), C. J. Conselice (Nottingham), S. P. Driver (St.
Andrews), J. Liske (ESO), D. Patton (Trent), A. Graham (Swinburne), P. Allen
(St. Andrews) | The Millennium Galaxy Catalogue: The connection between close pairs and
asymmetry; implications for the galaxy merger rate | 10 pages, 10 figures, emulateapj format. ApJ, accepted | Astrophys.J.666:212-221,2007 | 10.1086/520488 | null | astro-ph | null | We compare the use of galaxy asymmetry and pair proximity for measuring
galaxy merger fractions and rates for a volume limited sample of 3184 galaxies
with -21 < M(B) -5 log h < -18 mag. and 0.010 < z < 0.123 drawn from the
Millennium Galaxy Catalogue. Our findings are that:
(i) Galaxies in close pairs are generally more asymmetric than isolated
galaxies and the degree of asymmetry increases for closer pairs. At least 35%
of close pairs (with projected separation of less than 20 h^{-1} kpc and
velocity difference of less than 500 km s^{-1}) show significant asymmetry and
are therefore likely to be physically bound.
(ii) Among asymmetric galaxies, we find that at least 80% are either
interacting systems or merger remnants. However, a significant fraction of
galaxies initially identified as asymmetric are contaminated by nearby stars or
are fragmented by the source extraction algorithm. Merger rates calculated via
asymmetry indices need careful attention in order to remove the above sources
of contamination, but are very reliable once this is carried out.
(iii) Close pairs and asymmetries represent two complementary methods of
measuring the merger rate. Galaxies in close pairs identify future mergers,
occurring within the dynamical friction timescale, while asymmetries are
sensitive to the immediate pre-merger phase and identify remnants.
(iv) The merger fraction derived via the close pair fraction and asymmetries
is about 2% for a merger rate of (5.2 +- 1.0) 10^{-4} h^3 Mpc^{-3} Gyr^{-1}.
These results are marginally consistent with theoretical simulations (depending
on the merger time-scale), but imply a flat evolution of the merger rate with
redshift up to z ~1.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 13:35:42 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"De Propris",
"R.",
"",
"CTIO"
],
[
"Conselice",
"C. J.",
"",
"Nottingham"
],
[
"Driver",
"S. P.",
"",
"St.\n Andrews"
],
[
"Liske",
"J.",
"",
"ESO"
],
[
"Patton",
"D.",
"",
"Trent"
],
[
"Graham",
"A.",
"",
"Swinburne"
],
[
"Allen",
"P.",
"",
"St. Andrews"
]
] |
0705.2529 | Vitaly Zuev S. | V.S.Zuev, H.Ya.Zueva | Surface waves on metal-dielectric boundaries on the frequency of
$\omega_{pl}$ | 5 pages, 4 figures | null | null | null | physics.optics | null | Surface optical plasmons on metal-dielectric boundaries of various shapes are
studied. The study features by the exploration of plasmons of the frequency
that is larger than $\omega_{pl}/\sqrt{2}$ and approximately equal to $\omega
_{pl}$. These plasmons exist on thin films, thin cylinders, and on spheres.
Such a plasmon does not exist on a single surface. For applications the use of
plasmons of the ~$\omega_{pl}$ frequency means the promotion of nanophotonics
devices into a short wavelength range. For Ag this means the promotion to the
wavelength of 140 nm.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 13:36:41 GMT"
},
{
"version": "v2",
"created": "Fri, 18 May 2007 09:27:14 GMT"
},
{
"version": "v3",
"created": "Thu, 24 May 2007 11:37:19 GMT"
}
] | 2007-06-13T00:00:00 | [
[
"Zuev",
"V. S.",
""
],
[
"Zueva",
"H. Ya.",
""
]
] |
0705.2530 | Maxim Lyutikov | Maxim Lyutikov (Purdue University) | On generation of Crab giant pulses | accepted by MNRAS; added estimate of simultaneous GLAST signal | null | 10.1111/j.1365-2966.2007.12318.x | null | astro-ph | null | We propose that Crab giant pulses are generated on closed magnetic field
lines near the light cylinder via anomalous cyclotron resonance on the ordinary
mode. Waves are generated in a set of fine, unequally spaced, narrow emission
bands at frequencies much lower than a local cyclotron frequency. Location of
emission bands is fitted to spectral structures seen by Eilek et al. (2006).
To reproduce the data, the required density of plasma in the giant pulses
emission region is much higher, by a factor $\sim 3 \times 10^5$, than the
minimal Goldreich-Julian density. Emission is generated by a population of
highly energetic particles with radiation-limited Lorentz factors $\gamma \sim
7 \times 10^7$, produced during occasional reconnection close to the Y point,
where the last closed field lines approach the light cylinder.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 15:29:41 GMT"
},
{
"version": "v2",
"created": "Mon, 6 Aug 2007 19:19:38 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Lyutikov",
"Maxim",
"",
"Purdue University"
]
] |
0705.2531 | Brendan Douglas | B. L. Douglas, J. B. Wang | Classical approach to the graph isomorphism problem using quantum walks | null | J. Phys. A: Math. Theor. 41 (2008) 075303 | 10.1088/1751-8113/41/7/075303 | null | quant-ph | null | Given the extensive application of classical random walks to classical
algorithms in a variety of fields, their quantum analogue in quantum walks is
expected to provide a fruitful source of quantum algorithms. So far, however,
such algorithms have been scarce. In this work, we enumerate some important
differences between quantum and classical walks, leading to their markedly
different properties. We show that for many practical purposes, the
implementation of quantum walks can be efficiently achieved using a classical
computer. We then develop both classical and quantum graph isomorphism
algorithms based on discrete-time quantum walks. We show that they are
effective in identifying isomorphism classes of large databases of graphs, in
particular groups of strongly regular graphs. We consider this approach to
represent a promising candidate for an efficient solution to the graph
isomorphism problem, and believe that similar methods employing quantum walks,
or derivatives of these walks, may prove beneficial in constructing other
algorithms for a variety of purposes.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 14:09:47 GMT"
},
{
"version": "v2",
"created": "Wed, 26 Mar 2008 10:08:04 GMT"
}
] | 2008-03-26T00:00:00 | [
[
"Douglas",
"B. L.",
""
],
[
"Wang",
"J. B.",
""
]
] |
0705.2532 | Pranav Saxena | Pranav Saxena (Rajasthan University), Prachi Parashar (Oklahoma
University), N.K. Sharma, Ashok K. Nagawat, Sardar Singh (Rajasthan
University) | Signatures of Heavy Z-prime in the Extra U(1) Superstring Inspired
Model: RGEs Analysis | Total 76 pages including 19 Figures and 6 Tables | null | null | thepuor/2007/001 | hep-ph | null | In the extra U(1) superstring inspired model, we examine the electroweak and
U(1)-prime symmetry breaking with the singlet and exotic quark D, D+{\c}along
with the study of heavy Z-prime boson in accordance with the top quark mass
region. For this, we have done the analysis of complete renormalization group
equations (RGEs)pertaining to the anomaly free E-{\6}-Eta model of rank 5. The
Z-prime is found to the order of TeV or above with allowed small Z-Zprime
mixing angle, for which the large singlet VEV is required. This is done by
considering the only non-universality of Yukawa couplings at GUT scale because
these do not obey the E-{\6}relationship and also satisfies the unitarity
constraints both at GUT and weak scale, where rest of the parameters, i.e.,
gaugino masses, tri-linear couplings, and soft supersymmetric breaking masses
are kept universal at GUT scale with the gauge couplings unification. The large
value of Yukawa couplings (order of 1) triggered the symmetry breaking
radiatively and induces the effective-Mu parameter at the electroweak scale and
lead to a viable low energy spectrum at weak scale.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 14:11:22 GMT"
},
{
"version": "v2",
"created": "Fri, 18 May 2007 06:07:49 GMT"
},
{
"version": "v3",
"created": "Mon, 21 May 2007 11:22:02 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Saxena",
"Pranav",
"",
"Rajasthan University"
],
[
"Parashar",
"Prachi",
"",
"Oklahoma\n University"
],
[
"Sharma",
"N. K.",
"",
"Rajasthan\n University"
],
[
"Nagawat",
"Ashok K.",
"",
"Rajasthan\n University"
],
[
"Singh",
"Sardar",
"",
"Rajasthan\n University"
]
] |
0705.2533 | T. Padmanabhan | T. Padmanabhan | Dark Energy and Gravity | Invited Review for a special Gen.Rel.Grav. issue on Dark Energy,
edited by G.F.R.Ellis, R.Maartens and H.Nicolai; revtex; 22 pages; 2 figures | Gen.Rel.Grav.40:529-564,2008 | 10.1007/s10714-007-0555-7 | null | gr-qc astro-ph hep-th | null | I review the problem of dark energy focusing on the cosmological constant as
the candidate and discuss its implications for the nature of gravity. Part 1
briefly overviews the currently popular `concordance cosmology' and summarises
the evidence for dark energy. It also provides the observational and
theoretical arguments in favour of the cosmological constant as the candidate
and emphasises why no other approach really solves the conceptual problems
usually attributed to the cosmological constant. Part 2 describes some of the
approaches to understand the nature of the cosmological constant and attempts
to extract the key ingredients which must be present in any viable solution. I
argue that (i)the cosmological constant problem cannot be satisfactorily solved
until gravitational action is made invariant under the shift of the matter
lagrangian by a constant and (ii) this cannot happen if the metric is the
dynamical variable. Hence the cosmological constant problem essentially has to
do with our (mis)understanding of the nature of gravity. Part 3 discusses an
alternative perspective on gravity in which the action is explicitly invariant
under the above transformation. Extremizing this action leads to an equation
determining the background geometry which gives Einstein's theory at the lowest
order with Lanczos-Lovelock type corrections. (Condensed abstract).
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 18:26:39 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Padmanabhan",
"T.",
""
]
] |
0705.2534 | Ashok Das | Ashok Das and J. Frenkel | Thermal Operator and Dispersion Relation in QED at Finite Temperature
and Chemical Potential | 5 pages, revtex | Phys.Rev.D76:087701,2007 | 10.1103/PhysRevD.76.087701 | null | hep-th | null | Combining the thermal operator representation with the dispersion relation in
QED at finite temperature and chemical potential, we determine the complete
retarded photon self-energy only from its absorptive part at zero temperature.
As an application of this method, we show that, even for the case of a nonzero
chemical potential, the temperature dependent part of the one loop retarded
photon self-energy vanishes in $(1+1)$ dimensional massless QED.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 14:19:12 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Das",
"Ashok",
""
],
[
"Frenkel",
"J.",
""
]
] |
0705.2535 | Oded Kafri | Oded Kafri | Informatics Carnot Machine | null | null | null | null | cs.IT math.IT | null | Based on Planck's blackbody equation it is argued that a single mode light
pulse, with a large number of photons, carries one entropy unit. Similarly, an
empty radiation mode carries no entropy. In this case, the calculated entropy
that a coded sequence of light pulses is carrying is simply the Gibbs mixing
entropy, which is identical to the logical Shannon information. This approach
is supported by a demonstration that information transmission and
amplification, by a sequence of light pulses in an optical fiber, is a classic
Carnot machine comprising of two isothermals and two adiabatic. Therefore it is
concluded that entropy under certain conditions is information.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 14:45:08 GMT"
}
] | 2007-07-13T00:00:00 | [
[
"Kafri",
"Oded",
""
]
] |
0705.2536 | Alessandro Gruppuso | Alessandro Gruppuso | A Complete Statistical Analysis for the Quadrupole Amplitude in an
Ellipsoidal Universe | 5 pages, 3 figures | Phys.Rev.D76:083010,2007 | 10.1103/PhysRevD.76.083010 | null | astro-ph | null | A model of Universe with a small eccentricity due to the presence of a
magnetic field at the decoupling time (i.e. an Ellipsoidal Universe) has been
recently proposed for the solution of the low quadrupole anomaly of the angular
power spectrum of cosmic microwave background anisotropies. We present a
complete statistical analysis of that model showing that the probability of
increasing of the amplitude of the quadrupole is larger than the probability of
decreasing in the whole parameters' space.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 16:32:42 GMT"
}
] | 2008-12-18T00:00:00 | [
[
"Gruppuso",
"Alessandro",
""
]
] |
0705.2537 | Alberto Tonolo | Francesca Mantese, Alberto Tonolo | Reflexivity in Derived Categories | null | null | null | null | math.KT math.CT | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | An adjoint pair of contravariant functors between abelian categories can be
extended to the adjoint pair of their derived functors in the associated
derived categories. We describe the reflexive complexes and interpret the
achieved results in terms of objects of the initial abelian categories. In
particular we prove that, for functors of any finite cohomological dimension,
the objects of the initial abelian categories which are reflexive as stalk
complexes form the largest class where a Cotilting Theorem in the sense of
Colby and Fuller works.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 14:58:52 GMT"
},
{
"version": "v2",
"created": "Wed, 20 May 2009 13:31:30 GMT"
}
] | 2009-05-20T00:00:00 | [
[
"Mantese",
"Francesca",
""
],
[
"Tonolo",
"Alberto",
""
]
] |
0705.2538 | Michel R. P. Planat | Michel R. P. Planat (FEMTO-ST), Anne-C\'eline Baboin (FEMTO-ST), Metod
Saniga (FEMTO-ST, Astrinstsav) | Multi-Line Geometry of Qubit-Qutrit and Higher-Order Pauli Operators | 8 pages, 6 figures. International Journal of Theoretical Physics
(2007) accept\'e | International Journal of Theoretical Physics 47 (2008) 1127-1135 | 10.1007/s10773-007-9541-9 | null | quant-ph math-ph math.MP | null | The commutation relations of the generalized Pauli operators of a
qubit-qutrit system are discussed in the newly established graph-theoretic and
finite-geometrical settings. The dual of the Pauli graph of this system is
found to be isomorphic to the projective line over the product ring Z2xZ3. A
"peculiar" feature in comparison with two-qubits is that two distinct
points/operators can be joined by more than one line. The multi-line property
is shown to be also present in the graphs/geometries characterizing two-qutrit
and three-qubit Pauli operators' space and surmised to be exhibited by any
other higher-level quantum system.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 15:00:35 GMT"
},
{
"version": "v2",
"created": "Tue, 12 Jun 2007 15:33:09 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Planat",
"Michel R. P.",
"",
"FEMTO-ST"
],
[
"Baboin",
"Anne-Céline",
"",
"FEMTO-ST"
],
[
"Saniga",
"Metod",
"",
"FEMTO-ST, Astrinstsav"
]
] |
0705.2539 | Philipp Gerhold | P. Gerhold, K. Jansen | The phase structure of a chirally invariant lattice Higgs-Yukawa model
for small and for large values of the Yukawa coupling constant | 21 pages, 6 figures, added references | JHEP 0709:041,2007 | 10.1088/1126-6708/2007/09/041 | HU-EP-07/16, DESY 07-063 | hep-lat | null | We consider a chirally invariant lattice Higgs-Yukawa model based on the
Neuberger overlap operator. As a first step towards the eventual determination
of Higgs mass bounds we study the phase diagram of the model analytically in
the large Nf-limit. We present an expression for the effective potential at
tree-level in the regime of small Yukawa and quartic coupling constants and
determine the order of the phase transitions. In the case of strong Yukawa
couplings the model effectively becomes an O(4)-symmetric non-linear
sigma-model for all values of the quartic coupling constant. This leads to the
existence of a symmetric phase also in the regime of large values of the Yukawa
coupling constant. On finite and small lattices, however, strong finite volume
effects prevent the expectation value of the Higgs field from vanishing thus
obscuring the existence of the symmetric phase at strong Yukawa couplings.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 15:01:26 GMT"
},
{
"version": "v2",
"created": "Tue, 26 Jun 2007 18:13:18 GMT"
}
] | 2010-10-27T00:00:00 | [
[
"Gerhold",
"P.",
""
],
[
"Jansen",
"K.",
""
]
] |
0705.2540 | Leo Butler | Leo T. Butler, Boris Levit | A Bayesian approach to the estimation of maps between riemannian
manifolds | 20 pages, no figures published version includes correction to eq.s
31, 41, 43 | Mathematical Methods of Statistics. 16(4):1--17, 2007 | 10.3103/S1066530707040011 | null | math.ST stat.TH | null | Let \Theta be a smooth compact oriented manifold without boundary, embedded
in a euclidean space and let \gamma be a smooth map \Theta into a riemannian
manifold \Lambda. An unknown state \theta \in \Theta is observed via
X=\theta+\epsilon \xi where \epsilon>0 is a small parameter and \xi is a white
Gaussian noise. For a given smooth prior on \Theta and smooth estimator g of
the map \gamma we derive a second-order asymptotic expansion for the related
Bayesian risk. The calculation involves the geometry of the underlying spaces
\Theta and \Lambda, in particular, the integration-by-parts formula. Using this
result, a second-order minimax estimator of \gamma is found based on the modern
theory of harmonic maps and hypo-elliptic differential operators.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 15:01:50 GMT"
},
{
"version": "v2",
"created": "Tue, 25 Mar 2008 17:33:12 GMT"
}
] | 2008-03-25T00:00:00 | [
[
"Butler",
"Leo T.",
""
],
[
"Levit",
"Boris",
""
]
] |
0705.2541 | Alejandro Rodriguez | Peter Bermel, Alejandro Rodriguez, John D. Joannopoulos and Marin
Soljacic | Tailoring optical nonlinearities via the Purcell effect | null | null | 10.1103/PhysRevLett.99.053601 | null | quant-ph | null | We predict that the effective nonlinear optical susceptibility can be
tailored using the Purcell effect. While this is a general physical principle
that applies to a wide variety of nonlinearities, we specifically investigate
the Kerr nonlinearity. We show theoretically that using the Purcell effect for
frequencies close to an atomic resonance can substantially influence the
resultant Kerr nonlinearity for light of all (even highly detuned) frequencies.
For example, in realistic physical systems, enhancement of the Kerr coefficient
by one to two orders of magnitude could be achieved.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 16:46:56 GMT"
},
{
"version": "v2",
"created": "Thu, 28 Jun 2007 16:41:55 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Bermel",
"Peter",
""
],
[
"Rodriguez",
"Alejandro",
""
],
[
"Joannopoulos",
"John D.",
""
],
[
"Soljacic",
"Marin",
""
]
] |
0705.2542 | Barry McKernan | Barry McKernan (CUNY/Amnh), Tahir Yaqoob (JHU/NASA GSFC) and Chris
Reynolds (UMd) | A soft X-ray study of Type I AGN observed with Chandra HETGS | MNRAS accepted, 17 pages | Mon.Not.Roy.Astron.Soc.379:1359-1372,2007 | 10.1111/j.1365-2966.2007.11993.x | null | astro-ph | null | We present the results of a uniform analysis of the soft X-ray spectra of
fifteen type I AGN observed with the high resolution X-ray gratings on board
\emph{Chandra}. We found that ten of the fifteen AGN exhibit signatures of an
intrinsic ionized absorber. The absorbers are photoionized and outflowing, with
velocities in the range $\sim 10^{1}-10^{3}$ km $\rm{s}^{-1}$. The column
density of the warm absorbing gas is $\sim 10^{20-23} \rm{cm}^{-2}$. Nine of
the ten AGN exhibiting warm absorption are best--fit by multiple ionization
components and three of the ten AGN \emph{require} multiple kinematic
components. The warm absorbing gas in our AGN sample has a wide range of
ionization parameter, spanning roughly four orders of magnitude ($\xi \sim
10^{0-4}$ ergs cm $\rm{s}^{-1}$) in total, and often spanning three orders of
magnitude in the same gas. Warm absorber components with ionization parameter
$\xi<10$ generate an unresolved transition array due to Fe in seven of the ten
AGN exhibiting warm absorption. These low ionization state absorbers may also
carry away the largest mass outflows from the AGN. The mass outflow rate
depends critically on the volume filling factor of the gas, which cannot yet be
directly measured. However, upper limits on the mass outflow ratesfor filling
factors of unity can be much greater than the expected accretion rate onto the
central supermassive black hole and filling factors as small as 1% can give
outflow rates comparable to the accretion rate. There appears to be a gap in
the outflow velocities in our sample between $\sim 300-500$ km $\rm{s}^{-1}$,
the origin of which is not clear. The outflow components with velocities below
this gap tend to be associated with lower column densities than those with
velocities above the gap.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 17:22:19 GMT"
}
] | 2019-08-19T00:00:00 | [
[
"McKernan",
"Barry",
"",
"CUNY/Amnh"
],
[
"Yaqoob",
"Tahir",
"",
"JHU/NASA GSFC"
],
[
"Reynolds",
"Chris",
"",
"UMd"
]
] |
0705.2543 | Yuan Liu | Yuan Liu, Shuang Nan Zhang | The Lorentz factor distribution and luminosity function of relativistic
jets in AGNs | 18 pages, 7 figures. The original version of this paper was submitted
to ApJL on January 19, 2007. The current version was submitted to ApJ on
April 15, 2007 and accepted on May 16, 2007 | null | 10.1086/520040 | null | astro-ph | null | The observed apparent velocities and luminosities of the relativistic jets in
AGNs are significantly different from their intrinsic values due to strong
special relativistic effects. We adopt the maximum likelihood method to
determine simultaneously the intrinsic luminosity function and the Lorentz
factor distribution of a sample of AGNs. The values of the best estimated
parameters are consistent with the previous results, but with much better
accuracy. In previous study, it was assumed that the shape of the observed
luminosity function of Fanaroff-Riley type II radio galaxies is the same with
the intrinsic luminosity function of radio loud quasars. Our results prove the
validity of this assumption. We also find that low and high redshift groups
divided by z=0.1 are likely to be from different parent populations.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 15:08:52 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Liu",
"Yuan",
""
],
[
"Zhang",
"Shuang Nan",
""
]
] |
0705.2544 | Veerle Hellemans | V. Hellemans, P. Van Isacker, S. De Baerdemacker, K. Heyde | Criticality in the configuration-mixed interacting boson model : (1)
$U(5)-\hat{Q}(\chi)\cdot\hat{Q}(\chi)$ mixing | null | Nucl.Phys.A789:164-181,2007; Erratum-ibid.A801:80-81,2008 | 10.1016/j.nuclphysa.2007.04.003 10.1016/j.nuclphysa.2007.12.003 | null | nucl-th | null | The case of U(5)--$\hat{Q}(\chi)\cdot\hat{Q}(\chi)$ mixing in the
configuration-mixed Interacting Boson Model is studied in its mean-field
approximation. Phase diagrams with analytical and numerical solutions are
constructed and discussed. Indications for first-order and second-order shape
phase transitions can be obtained from binding energies and from critical
exponents, respectively.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 15:09:56 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Hellemans",
"V.",
""
],
[
"Van Isacker",
"P.",
""
],
[
"De Baerdemacker",
"S.",
""
],
[
"Heyde",
"K.",
""
]
] |
0705.2545 | Reinhard Kremer | Diaz-Luis, A.H. Romero, M. Cardona, R. K. Kremer, X. Gonze | Effect of the spin-orbit interaction on the thermodynamic properties of
crystals: The specific heat of bismuth | 4 pages, 3 figures | null | null | null | cond-mat.mtrl-sci | null | In recent years, there has been increasing interest in the specific heat $C$
of insulators and semiconductors because of the availability of samples with
different isotopic masses and the possibility of performing \textit{ab initio}
calculations of its temperature dependence $C(T)$ using as a starting point the
electronic band structure. Most of the crystals investigated are elemental
(e.g., germanium) or binary (e.g., gallium nitride) semiconductors. The initial
electronic calculations were performed in the local density approximation and
did not include spin-orbit interaction. Agreement between experimental and
calculated results was usually found to be good, except for crystals containing
heavy atoms (e.g., PbS) for which discrepancies of the order of 20% existed at
the low temperature maximum found for $C/T^3$. It has been conjectured that
this discrepancies result from the neglect of spin-orbit interaction which is
large for heavy atoms ($\Delta_0\sim$1.3eV for the $p$ valence electrons of
atomic lead). Here we discuss measurements and \textit{ab initio} calculations
of $C(T)$ for crystalline bismuth ($\Delta_0\sim$1.7 eV), strictly speaking a
semimetal but in the temperature region accessible to us ($T >$ 2K) acting as a
semiconductor. We extend experimental data available in the literature and
notice that the \textit{ab initio} calculations without spin-orbit interaction
exhibit a maximum at $\sim$8K, about 20% lower than the measured one. Inclusion
of spin-orbit interaction decreases the discrepancy markedly: The maximum of
$C(T)$ is now only 7% larger than the measured one. Exact agreement is obtained
if the spin-orbit hamiltonian is reduced by a factor of $\sim$0.8.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 15:13:40 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Diaz-Luis",
"",
""
],
[
"Romero",
"A. H.",
""
],
[
"Cardona",
"M.",
""
],
[
"Kremer",
"R. K.",
""
],
[
"Gonze",
"X.",
""
]
] |
0705.2546 | Alexander Dranishnikov | Alexander Dranishnikov | On asymptotic dimension of amalgamated products and right-angled Coxeter
groups | 12 pages | Algebr. Geom. Topol. 8 (2008) 1281-1293 | 10.2140/agt.2008.8.1281 | null | math.GR math.MG | null | We prove the inequality $$ \as A\ast_CB\le\max\{\as A,\as B,\as C+1\} $$ and
we apply this inequality to show that the asymptotic dimension of any
right-angled Coxeter group does not exceed the dimension of its Davis' complex.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 15:15:25 GMT"
},
{
"version": "v2",
"created": "Sat, 23 Jun 2007 15:34:52 GMT"
},
{
"version": "v3",
"created": "Wed, 19 Dec 2007 21:59:01 GMT"
}
] | 2014-10-01T00:00:00 | [
[
"Dranishnikov",
"Alexander",
""
]
] |
0705.2547 | Victor Gichev | V.M. Gichev | Some remarks on spherical harmonics | 20 pages. Translation of the version which is published in Russian.
Minor modifications throughout the paper. An error in calculation is
corrected (page 14) | Algebra i Analiz, 2008, V. 20, No 4, 64--86 (in Russian) | null | null | math.CA math.MG | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The article contains several observations on spherical harmonics and their
nodal sets: a construction for harmonics with prescribed zeroes; a kind of
canonical representation of this type for harmonics on $\bbS^2$; upper and
lower bounds for nodal length and inner radius (the upper bounds are sharp);
precise upper bound for the number of common zeroes of two spherical harmonics
on $\bbS^2$; the mean Hausdorff measure on the intersection of $k$ nodal sets
for harmonics of different degrees on $\bbS^m$, where $k\leq m$ (in particular,
the mean number of common zeroes of $m$ harmonics).
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 15:16:31 GMT"
},
{
"version": "v2",
"created": "Fri, 31 Aug 2007 16:46:37 GMT"
},
{
"version": "v3",
"created": "Wed, 6 Aug 2008 19:45:23 GMT"
}
] | 2008-08-06T00:00:00 | [
[
"Gichev",
"V. M.",
""
]
] |
0705.2548 | Sanhita Joshi | S.A. Joshi, R.A. Battye, I.W.A. Browne, N. Jackson, T.W.B. Muxlow,
P.N. Wilkinson | The polarization in the JVAS/CLASS flat-spectrum radio sources: II. A
search for aligned radio polarizations | 13 pages, 11 figures, 1 table, accepted for publication by MNRAS | Mon.Not.Roy.Astron.Soc.380:162-174,2007 | 10.1111/j.1365-2966.2007.12028.x | null | astro-ph | null | We have used the very large JVAS/CLASS 8.4-GHz surveys of flat-spectrum radio
sources to test the hypothesis that there is a systematic alignment of
polarization position angle vectors on cosmological scales of the type claimed
by Hutsemekers et al (2005). The polarization position angles of 4290 sources
with polarized flux density >=1 mJy have been examined. They do not reveal
large-scale alignments either as a whole or when split in half into
high-redshift (z >= 1.24) and low-redshift sub-samples. Nor do the radio
sources which lie in the specific areas covered by Hutsemekers et al (2005).
show any significant effect. We have also looked at the position angles of
parsec-scale jets derived from VLBI observations and again find no evidence for
systematic alignments. Finally, we have investigated the correlation between
the polarization position angle and those of the parsec-scale jets. As
expected, we find that there is a tendency for the polarization angles to be
perpendicular to the jet angles. However, the difference in jet and
polarization position angles does not show any systematic trend in different
parts of the sky.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 15:18:29 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"Joshi",
"S. A.",
""
],
[
"Battye",
"R. A.",
""
],
[
"Browne",
"I. W. A.",
""
],
[
"Jackson",
"N.",
""
],
[
"Muxlow",
"T. W. B.",
""
],
[
"Wilkinson",
"P. N.",
""
]
] |
0705.2549 | Daowen Qiu | Lvzhou Li and Daowen Qiu | Optimal discrimination between quantum operations | 6 pages (revtex4 version); comments are welcome | Journal of Physics A: Math. Theor. 41, 335302 (2008). | 10.1088/1751-8113/41/33/335302 | null | quant-ph | null | In this paper, we address the problem of discriminating two given quantum
operations. Firstly, based on the Bloch representation of single qubit systems,
we give the exact minimum error probability of discriminating two single qubit
quantum operations by unentangled input states. In particular, for the Pauli
channels discussed in [Phys. Rev. A {\bf 71}, 062340 (2005)], we use a more
intuitional and visual method to deal with their discrimination problem.
Secondly, we consider the condition for perfect discrimination of two quantum
operations. Specially, we get that two generalized Pauli channels are perfectly
distinguishable if and only if their characteristic vectors are orthogonal.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 15:39:21 GMT"
}
] | 2010-03-10T00:00:00 | [
[
"Li",
"Lvzhou",
""
],
[
"Qiu",
"Daowen",
""
]
] |
0705.2550 | Smagul Karazhanov Zh. | S. Zh. Karazhanov, P. Ravindran, A. Kjekshus, H. Fjellvag, B. G.
Svensson | Electronic structure and optical properties of ZnX (X=O, S, Se, Te) | 17 pages, 10 figures | Phys. Rev. B, 75, 155104 (2007) | 10.1103/PhysRevB.75.155104 | null | cond-mat.soft cond-mat.mtrl-sci | null | Electronic band structure and optical properties of zinc monochalcogenides
with zinc-blende- and wurtzite-type structures were studied using the ab initio
density functional method within the LDA, GGA, and LDA+U approaches.
Calculations of the optical spectra have been performed for the energy range
0-20 eV, with and without including spin-orbit coupling. Reflectivity,
absorption and extinction coefficients, and refractive index have been computed
from the imaginary part of the dielectric function using the Kramers--Kronig
transformations. A rigid shift of the calculated optical spectra is found to
provide a good first approximation to reproduce experimental observations for
almost all the zinc monochalcogenide phases considered. By inspection of the
calculated and experimentally determined band-gap values for the zinc
monochalcogenide series, the band gap of ZnO with zinc-blende structure has
been estimated.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 15:40:02 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Karazhanov",
"S. Zh.",
""
],
[
"Ravindran",
"P.",
""
],
[
"Kjekshus",
"A.",
""
],
[
"Fjellvag",
"H.",
""
],
[
"Svensson",
"B. G.",
""
]
] |
0705.2551 | Sun-Chong Wang | S.C. Wang, J.J. Tseng, C.C. Tai, K.H. Lai, W.S. Wu, S.H. Chen, S.P. Li | Network Topology of an Experimental Futures Exchange | 6 pages, 12 figures | null | 10.1140/epjb/e2008-00119-8 | null | q-fin.ST physics.soc-ph | null | Many systems of different nature exhibit scale free behaviors. Economic
systems with power law distribution in the wealth is one of the examples. To
better understand the working behind the complexity, we undertook an empirical
study measuring the interactions between market participants. A Web server was
setup to administer the exchange of futures contracts whose liquidation prices
were coupled to event outcomes. After free registration, participants started
trading to compete for the money prizes upon maturity of the futures contracts
at the end of the experiment. The evolving `cash' flow network was
reconstructed from the transactions between players. We show that the network
topology is hierarchical, disassortative and scale-free with a power law
exponent of 1.02+-0.09 in the degree distribution. The small-world property
emerged early in the experiment while the number of participants was still
small. We also show power law distributions of the net incomes and
inter-transaction time intervals. Big winners and losers are associated with
high degree, high betweenness centrality, low clustering coefficient and low
degree-correlation. We identify communities in the network as groups of the
like-minded. The distribution of the community sizes is shown to be power-law
distributed with an exponent of 1.19+-0.16.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 15:43:04 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Wang",
"S. C.",
""
],
[
"Tseng",
"J. J.",
""
],
[
"Tai",
"C. C.",
""
],
[
"Lai",
"K. H.",
""
],
[
"Wu",
"W. S.",
""
],
[
"Chen",
"S. H.",
""
],
[
"Li",
"S. P.",
""
]
] |
0705.2552 | Christian Boily | C.M. Boily and E. Athanassoula | On the equilibrium morphology of systems drawn from spherical collapse
experiments | 16 pages | Mon.Not.Roy.Astron.Soc.369:608,2006 | 10.1111/j.1365-2966.2006.10365.x | null | astro-ph | null | We present a purely theoretical study of the morphological evolution of
self-gravitating systems formed through the dissipationless collapse of N-point
sources. We explore the effects of resolution in mass and length on the growth
of triaxial structures formed by an instability triggered by an excess of
radial orbits. We point out that as resolution increases, the equilibria shift,
from mildly prolate, to oblate. A number of particles N ~= 100000 or larger is
required for convergence of axial aspect ratios. An upper bound for the
softening, e ~ 1/256, is also identified. We then study the properties of a set
of equilibria formed from scale-free cold initial mass distributions, ro ~ r^-g
with 0 <= g <= 2. Oblateness is enhanced for initially more peaked structures
(larger values of g). We map the run of density in space and find no evidence
for a power-law inner structure when g <= 3/2 down to a mass fraction <~0.1 per
cent of the total. However, when 3/2 < g <= 2, the mass profile in equilibrium
is well matched by a power law of index ~g out to a mass fraction ~ 10 per
cent. We interpret this in terms of less-effective violent relaxation for more
peaked profiles when more phase mixing takes place at the centre. We map out
the velocity field of the equilibria and note that at small radii the velocity
coarse-grained distribution function (DF) is Maxwellian to a very good
approximation.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 15:52:50 GMT"
}
] | 2019-08-19T00:00:00 | [
[
"Boily",
"C. M.",
""
],
[
"Athanassoula",
"E.",
""
]
] |
0705.2553 | Bernardo Barbiellini | D. Nissenbaum, B. Barbiellini and A. Bansil | Decorrelation of samples in Quantum Monte Carlo calculations and scaling
of autocorrelation time in Li and H$_{2}$O clusters | 4 pages, 2 figures, to appear in Phys. Rev. B | Phys. Rev. B 76, 033412 (2007) | 10.1103/PhysRevB.76.033412 | null | cond-mat.mtrl-sci cond-mat.other | null | We have investigated decorrelation of samples in Quantum Monte Carlo (QMC)
ground-state energy calculations for large Li and H$_{2}$O nanoclusters.
Binning data as a way of eliminating statistical correlations, as is the common
practice, is found to become increasingly impractical as the system size grows.
We demonstrate nevertheless that it is possible to perform accurate energy
calculations - without decorrelating samples - by exploiting the scaling of the
integrated autocorrelation time $\tau$ as a function of the number of electrons
in the system.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 19:59:10 GMT"
}
] | 2007-10-11T00:00:00 | [
[
"Nissenbaum",
"D.",
""
],
[
"Barbiellini",
"B.",
""
],
[
"Bansil",
"A.",
""
]
] |
0705.2554 | Joseph Johnson | Joseph F. Johnson | The Axiomatisation of Physics | for larger context and other links, see
http://euclid.unh.edu/~jjohnson | null | null | null | quant-ph | null | Analysing Quantum Measurement requires analysing the physics of amplification
since amplification of phenomena from one scale to another scale is essential
to measurement. There still remains the task of working this into an axiomatic
logical structure, what should be the foundational status of the concepts of
measurement and probability. We argue that the concept of physical probability
is a multi-scale phenomenon and as such, can be explicitly defined in terms of
more fundamental physical concepts. Thus Quantum Mechanics can be given a
logically unexceptionable axiomatisation. We introduce a new definition of
macroscopic observable which implements Bohr's insight that the observables of
a measurement apparatus are classical in nature. In particular, we obtain the
usual non-abelian observables as limits of abelian, classical, observables.
This is the essential step in Hilbert's Sixth Problem.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 16:00:38 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Johnson",
"Joseph F.",
""
]
] |
0705.2555 | Leonid Shifrin | Gernot Akemann, Leonid Shifrin | A Generalisation of Dyson's Integration Theorem for Determinants | 7 pages, Latex. v2: typos corrected + reference added. v3: degenerate
case added, to be published in J.Phys.A FTC | J.Phys.A40:F785-F792,2007 | 10.1088/1751-8113/40/32/F01 | null | math-ph cond-mat.stat-mech hep-th math.MP | null | Dyson's integration theorem is widely used in the computation of eigenvalue
correlation functions in Random Matrix Theory. Here we focus on the variant of
the theorem for determinants, relevant for the unitary ensembles with Dyson
index beta = 2. We derive a formula reducing the (n-k)-fold integral of an n x
n determinant of a kernel of two sets of arbitrary functions to a determinant
of size k x k. Our generalisation allows for sets of functions that are not
orthogonal or bi-orthogonal with respect to the integration measure. In the
special case of orthogonal functions Dyson's theorem is recovered.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 16:01:37 GMT"
},
{
"version": "v2",
"created": "Fri, 25 May 2007 19:28:55 GMT"
},
{
"version": "v3",
"created": "Fri, 6 Jul 2007 17:47:04 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Akemann",
"Gernot",
""
],
[
"Shifrin",
"Leonid",
""
]
] |
0705.2556 | Christian Boily | C.M. Boily, N. Nakastao, R. Spurzem and T. Tsuchiya | Satellite survival in cold dark matter cosmology | 5 pages, no figures | Astrophys.J.614:26,2004 | 10.1086/423421 | null | astro-ph | null | We study the survival of substructures (clumps) within larger
self-gravitating dark matter halos. Building on scaling relations obtained from
N-body calculations of violent relaxation, we argue that the tidal field of
galaxies and halos can only destroy substructures if spherical symmetry is
imposed at formation. We explore other mechanisms that may tailor the number of
halo substructures during the course of virialization. Unless the larger halo
is built up from a few large clumps, we find that clump-clump encounters are
unlikely to homogenize the halo on a dynamical timescale. Phase mixing would
proceed faster in the inner parts and allow for the secular evolution of a
stellar disk.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 16:07:09 GMT"
}
] | 2019-08-19T00:00:00 | [
[
"Boily",
"C. M.",
""
],
[
"Nakastao",
"N.",
""
],
[
"Spurzem",
"R.",
""
],
[
"Tsuchiya",
"T.",
""
]
] |
0705.2557 | Harry Lipkin J | Harry J. Lipkin | New systematics in charmless strange $B^+ \to VP$ decays | 12 pages | null | null | null | hep-ph | null | Latest data on charmless strange vector-pseudoscalar $B^+$ decays now
including $B^+\to \rho^+ K^o$ confirm a simple penguin model in which the gluon
$G$ in an initial $\bar s u G$ state fragments equally into $u \bar u$, $d \bar
d$ and $s \bar s$ and all form factors are equal. A search for possible
additional contributions shows only a few signals not obscured by experimental
errors whose implications are discussed. The experimental value of $0.25 \pm
0.11$ for the ratio of the branching ratios $BR(B^+ \to K^{*+}\eta)$ to
$BR(B^+\to K^{*+}\eta')$ confirms the parity selection rule prediction 0.32.
Large violations arise in a new sum rule for the sum of these branching ratios,
analogous to the similar pseudoscalar sum rule including $K^+\eta$ and
$K^+\eta'$. Indications for either an electroweak penguin contribution or
additional admixtures like instrinsic charm in the $\eta-\eta'$ system remain
to be clarified. An alternative symmetry description with new predictive power
clarifies the simple penguin approximation and presents new predictions which
can be tested experimentally. The fragmentation of the $\bar s u G$ state into
two mesons is described by a strong interaction S-matrix dominated by nonexotic
hadron resonances in multiparticle intermediate states.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 16:09:15 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Lipkin",
"Harry J.",
""
]
] |
0705.2558 | Paul Bird | Paul Bird | Invariance Mechanics - A new direction for quantum gravity | This paper has been withdrawn by the author | null | null | null | physics.gen-ph | null | This paper has been withdrawn by the author.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 16:13:36 GMT"
},
{
"version": "v2",
"created": "Fri, 25 May 2007 20:54:09 GMT"
},
{
"version": "v3",
"created": "Tue, 2 Aug 2011 21:01:29 GMT"
}
] | 2011-08-04T00:00:00 | [
[
"Bird",
"Paul",
""
]
] |
0705.2559 | Peter Petreczky | Agnes Mocsy, Peter Petreczky | Can quarkonia survive deconfinement ? | Version accepted in Phys. Rev. D, 20 pages, 25 figures | Phys.Rev.D77:014501,2008 | 10.1103/PhysRevD.77.014501 | BNL-NT-07/21, RBRC-677 | hep-ph hep-lat | null | We study quarkonium correlators and spectral functions at zero and finite
temperature in QCD with only heavy quarks using potential models combined with
perturbative QCD. First, we show that this approach can describe the quarkonium
correlation function at zero temperature. Using a class of screened potentials
based on lattice calculations of the static quark-antiquark free energy we
calculate spectral functions at finite temperature. We find that all quarkonium
states, with the exception of the $1S$ bottomonium, dissolve in the deconfined
phase at temperatures smaller than $1.5T_c$, in contradiction with the
conclusions of recent studies. Despite this the temperature dependence of the
quarkonium correlation functions calculated on the lattice is well reproduced
in our model. We also find that even in the absence of resonances the spectral
function at high temperatures is significantly enhanced over the spectral
function corresponding to free quark antiquark propagation.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 19:56:02 GMT"
},
{
"version": "v2",
"created": "Fri, 28 Dec 2007 19:23:55 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Mocsy",
"Agnes",
""
],
[
"Petreczky",
"Peter",
""
]
] |
0705.2560 | Xavier Castello | X. Castello, R. Toivonen, V. M. Eguiluz, J. Saramaki, K. Kaski and M.
San Miguel | Anomalous lifetime distributions and topological traps in ordering
dynamics | 7 pages; 6 figures | Europhysics Letters, 79, (2007) 66006 (1-6) | 10.1209/0295-5075/79/66006 | null | physics.soc-ph | null | We address the role of community structure of an interaction network in
ordering dynamics, as well as associated forms of metastability. We consider
the voter and AB model dynamics in a network model which mimics social
interactions. The AB model includes an intermediate state between the two
excluding options of the voter model. For the voter model we find dynamical
metastable disordered states with a characteristic mean lifetime. However, for
the AB dynamics we find a power law distribution of the lifetime of metastable
states, so that the mean lifetime is not representative of the dynamics. These
trapped metastable states, which can order at all time scales, originate in the
mesoscopic network structure.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 16:22:42 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Castello",
"X.",
""
],
[
"Toivonen",
"R.",
""
],
[
"Eguiluz",
"V. M.",
""
],
[
"Saramaki",
"J.",
""
],
[
"Kaski",
"K.",
""
],
[
"Miguel",
"M. San",
""
]
] |
0705.2561 | Zhi-Xi Wang | Zhen Wang and Zhixi Wang | The tripartite separability of density matrices of graphs | 12 pages | The Electronic J. Combinatorics, 14(2007), R40 | null | null | quant-ph | null | The density matrix of a graph is the combinatorial laplacian matrix of a
graph normalized to have unit trace. In this paper we generalize the
entanglement properties of mixed density matrices from combinatorial laplacian
matrices of graphs discussed in Braunstein {\it et al.} Annals of
Combinatorics, {\bf 10}(2006)291 to tripartite states. Then we proved that the
degree condition defined in Braunstein {\it et al.} Phys. Rev. A {\bf 73},
(2006)012320 is sufficient and necessary for the tripartite separability of the
density matrix of a nearest point graph.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 16:30:19 GMT"
},
{
"version": "v2",
"created": "Sat, 19 May 2007 13:26:49 GMT"
}
] | 2011-04-20T00:00:00 | [
[
"Wang",
"Zhen",
""
],
[
"Wang",
"Zhixi",
""
]
] |
0705.2562 | Delia Schwartz-Perlov | Ken D. Olum and Delia Schwartz-Perlov | Anthropic prediction in a large toy landscape | 13 pages | JCAP0710:010,2007 | 10.1088/1475-7516/2007/10/010 | null | hep-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The successful anthropic prediction of the cosmological constant depends
crucially on the assumption of a flat prior distribution. However, previous
calculations in simplified landscape models showed that the prior distribution
is staggered, suggesting a conflict with anthropic predictions. Here we
analytically calculate the full distribution, including the prior and anthropic
selection effects, in a toy landscape model with a realistic number of vacua,
$N \sim 10^{500}$. We show that it is possible for the fractal prior
distribution we find to behave as an effectively flat distribution in a wide
class of landscapes, depending on the regime of parameter space. Whether or not
this possibility is realized depends on presently unknown details of the
landscape.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 16:51:27 GMT"
},
{
"version": "v2",
"created": "Thu, 17 May 2007 20:00:13 GMT"
},
{
"version": "v3",
"created": "Tue, 29 Oct 2019 17:11:47 GMT"
}
] | 2019-10-30T00:00:00 | [
[
"Olum",
"Ken D.",
""
],
[
"Schwartz-Perlov",
"Delia",
""
]
] |
0705.2563 | Alberto Mariotti | Alberto Mariotti | Supersymmetric D-branes on SU(2) structure manifolds | Minor corrections, published in JHEP | JHEP0709:123,2007 | 10.1088/1126-6708/2007/09/123 | null | hep-th | null | We employ generalized complex geometry to investigate supersymmetric
embeddings of D-brane probes in a large class of SU(2) structure manifolds.
This class includes the gravity dual of mass deformation and marginal beta
deformation of N=4 SYM gauge theory. We find supersymmetric configurations of
D-branes with different dimensionality and propose their interpretation in the
dual gauge theory.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 16:56:46 GMT"
},
{
"version": "v2",
"created": "Wed, 18 Jul 2007 14:18:56 GMT"
},
{
"version": "v3",
"created": "Tue, 9 Oct 2007 17:11:52 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Mariotti",
"Alberto",
""
]
] |
0705.2564 | Frederik Denef | Frederik Denef, Gregory W. Moore | How many black holes fit on the head of a pin? | 4 pages, fourth prize in the Gravity Research Foundation Essay
competition 2007 | Int.J.Mod.Phys.D17:679-684,2008; Gen.Rel.Grav.39:1539-1544,2007 | 10.1007/s10714-007-0469-4 10.1142/S0218271808012437 | null | hep-th | null | The Bekenstein-Hawking entropy of certain black holes can be computed
microscopically in string theory by mapping the elusive problem of counting
microstates of a strongly gravitating black hole to the tractable problem of
counting microstates of a weakly coupled D-brane system, which has no event
horizon, and indeed comfortably fits on the head of a pin. We show here that,
contrary to widely held beliefs, the entropy of spherically symmetric black
holes can easily be dwarfed by that of stationary multi-black-hole
``molecules'' of the same total charge and energy. Thus, the corresponding
pin-sized D-brane systems do not even approximately count the microstates of a
single black hole, but rather those of a zoo of entropically dominant
multicentered configurations.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 17:06:14 GMT"
}
] | 2014-11-18T00:00:00 | [
[
"Denef",
"Frederik",
""
],
[
"Moore",
"Gregory W.",
""
]
] |
0705.2565 | Alexander Burin L | A. L. Burin, V. I. Kozub, Y. M. Galperin, V. Vinokur | Slow relaxation of conductance of amorphous hopping insulators | 6 pages, 1 figure | null | 10.1088/0953-8984/20/24/244135 | null | cond-mat.dis-nn cond-mat.mes-hall cond-mat.mtrl-sci | null | We discuss memory effects in the conductance of hopping insulators due to
slow rearrangements of structural defects leading to formation of polarons
close to the electron hopping states. An abrupt change in the gate voltage and
corresponding shift of the chemical potential change populations of the hopping
sites, which then slowly relax due to rearrangements of structural defects. As
a result, the density of hopping states becomes time dependent on a scale
relevant to rearrangement of the structural defects leading to the excess time
dependent conductivity.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 17:10:11 GMT"
},
{
"version": "v2",
"created": "Fri, 6 Jul 2007 02:03:03 GMT"
},
{
"version": "v3",
"created": "Sat, 10 May 2008 16:55:55 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Burin",
"A. L.",
""
],
[
"Kozub",
"V. I.",
""
],
[
"Galperin",
"Y. M.",
""
],
[
"Vinokur",
"V.",
""
]
] |
0705.2566 | Brent Pryor | Brent Pryor, Navin Khaneja | Fourier Synthesis Methods for Control of Inhomogeneous Quantum Systems | null | null | null | null | quant-ph | null | Finding control laws (pulse sequences) that can compensate for dispersions in
parameters which govern the evolution of a quantum system is an important
problem in the fields of coherent spectroscopy, imaging, and quantum
information processing. The use of composite pulse techniques for such tasks
has a long and widely known history. In this paper, we introduce the method of
Fourier synthesis control law design for compensating dispersions in quantum
system dynamics. We focus on system models arising in NMR spectroscopy and NMR
imaging applications.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 17:23:49 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Pryor",
"Brent",
""
],
[
"Khaneja",
"Navin",
""
]
] |
0705.2567 | Tomas Ortin | Jorge Bellorin and Tomas Ortin | Characterization of all the supersymmetric solutions of gauged N=1,d=5
supergravity | Some references and two comments added | JHEP0708:096,2007 | 10.1088/1126-6708/2007/08/096 | IFT-UAM/CSIC-07-22 | hep-th | null | We find a complete characterization of all the supersymmetric solutions of
non-Abelian gauged N=1,d=5 supergravity coupled to vector multiplets and
hypermultiplets: the generic forms of the metrics as functions of the scalars
and vector fields plus the equations that all these must satisfy. These
equations are now a complicated non-linear system and there it seems impossible
to produce an algorithm to construct systematically all supersymmetric
solutions.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 17:28:27 GMT"
},
{
"version": "v2",
"created": "Fri, 25 May 2007 14:04:54 GMT"
},
{
"version": "v3",
"created": "Sun, 24 Jun 2007 23:39:32 GMT"
},
{
"version": "v4",
"created": "Wed, 8 Aug 2007 19:13:17 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Bellorin",
"Jorge",
""
],
[
"Ortin",
"Tomas",
""
]
] |
0705.2568 | Lothar Fritsche | L. Fritsche and M. Haugk | Reexamining the Einstein-Podolsky-Rosen experiment, photon correlation
and Bell's inequality | 12 pages, 2 figures | null | null | null | physics.gen-ph | null | The purpose of this article is to show that the introduction of hidden
variables to describe individual events is fully consistent with the
statistical predictions of quantum theory. We illustrate the validity of this
assertion by discussing two fundamental experiments on correlated photons which
are believed to behave ``violently non-classical''. Our considerations carry
over to correlated pairs of neutral particles of spin one-half in a singlet
state. Much in the spirit of Einstein's conviction we come to the conclusion
that the state vector of a system does not provide an exhaustive description of
the individual physical system. We also briefly discuss an experiment on
``quantum teleportation'' and demonstrate that our completely local approach
leads to a full understanding of the experiment indicating the absence of any
teleportation phenomenon. We caution that the indiscriminated use of the term
``Quantum Theory'' tends to obscure distinct differences between the quantum
mechanics of massive particles and the propagation of photons. It is emphasized
that the properties of polarizers, beam splitters, halfwave plates etc. used in
photon-correlation experiments are defined by the laws of classical optics.
Hence, understanding the outcome of those experiments requires a well-founded
interconnection between classical and quantum electrodynamics free from
unnecessary hypotheses.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 17:19:48 GMT"
},
{
"version": "v2",
"created": "Tue, 7 Aug 2007 15:13:29 GMT"
}
] | 2007-08-07T00:00:00 | [
[
"Fritsche",
"L.",
""
],
[
"Haugk",
"M.",
""
]
] |
0705.2569 | Thomas Fernholz | T. Fernholz, R. Gerritsma, S. Whitlock, I. Barb, R. J. C. Spreeuw | Fully permanent magnet atom chip for Bose-Einstein condensation | changed title, substantial text modifications, journal reference
added | Phys. Rev. A 77, 033409 (2008) | 10.1103/PhysRevA.77.033409 | null | cond-mat.other | null | We describe a self-biased, fully permanent magnet atom chip used to study
ultracold atoms and to produce a Bose-Einstein condensate (BEC). The magnetic
trap is loaded efficiently by adiabatic transport of a magnetic trap via the
application of uniform external fields. Radio frequency spectroscopy is used
for in-trap analysis and to determine the temperature of the atomic cloud. The
formation of a Bose-Einstein condensate is observed in time of flight images
and as a narrow peak appearing in the radio frequency spectrum.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 17:38:21 GMT"
},
{
"version": "v2",
"created": "Mon, 24 Mar 2008 16:22:52 GMT"
}
] | 2008-03-24T00:00:00 | [
[
"Fernholz",
"T.",
""
],
[
"Gerritsma",
"R.",
""
],
[
"Whitlock",
"S.",
""
],
[
"Barb",
"I.",
""
],
[
"Spreeuw",
"R. J. C.",
""
]
] |
0705.2570 | Edwin Kellogg | E. Kellogg (1), C. Anderson (1), K. Korreck (1), J. DePasquale (1), J.
Nichols (1), J. L. Sokoloski (1), M. Krauss (2) and J. Pedelty (3) ((1)
Harvard/Smithsonian Center for Astrophysics, (2) Kavli Institute for
Astrophysics and Space Research, MIT, (3) NASA's Goddard Space Flight Center) | Outer jet X-ray and radio emission in R Aquarii: 1999.8 to 2004.0 | 23 pages, 8 figures | Astrophys.J.664:1079-1087,2007 | 10.1086/518877 | null | astro-ph | null | Chandra and VLA observations of the symbiotic star R Aqr in 2004 reveal
significant changes over the three to four year interval between these
observations and previous observations taken with the VLA in 1999 and with
Chandra in 2000. This paper reports on the evolution of the outer thermal X-ray
lobe-jets and radio jets. The emission from the outer X-ray lobe-jets lies
farther away from the central binary than the outer radio jets, and comes from
material interpreted as being shock heated to ~10^6 K, a likely result of
collision between high speed material ejected from the central binary and
regions of enhanced gas density. Between 2000 and 2004, the Northeast (NE)
outer X-ray lobe-jet moved out away from the central binary, with an apparent
projected motion of ~580 km s^-1. The Southwest (SW) outer X-ray lobe-jet
almost disappeared between 2000 and 2004, presumably due to adiabatic expansion
and cooling. The NE radio bright spot also moved away from the central binary
between 2000 and 2004, but with a smaller apparent velocity than of the NE
X-ray bright spot. The SW outer lobe-jet was not detected in the radio in
either 1999 or 2004. The density and mass of the X-ray emitting material is
estimated. Cooling times, shock speeds, pressure and confinement are discussed.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 17:40:38 GMT"
},
{
"version": "v2",
"created": "Thu, 17 May 2007 20:05:39 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"Kellogg",
"E.",
""
],
[
"Anderson",
"C.",
""
],
[
"Korreck",
"K.",
""
],
[
"DePasquale",
"J.",
""
],
[
"Nichols",
"J.",
""
],
[
"Sokoloski",
"J. L.",
""
],
[
"Krauss",
"M.",
""
],
[
"Pedelty",
"J.",
""
]
] |
0705.2571 | Mustapha Bentaiba | S.-A. Yahiaoui, O. Cherroud, M. Bentaiba | The effective potential and resummation procedure to multidimensional
complex cubic potentials for weak and strong-coupling | 19 pages, 0 figure | J.Math.Phys.48:113503,2007 | 10.1063/1.2760354 | null | math-ph math.MP | null | The method for the recursive calculation of the effective potential is
applied successfully in case of weak coupling limit (g tend to zero) to a
multidimensional complex cubic potential. In strong-coupling limit (g tend to
infinity), the result is resumed using the variational perturbation theory
(VPT). It is found that the convergence of VPT-results approaches those
expected.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 16:18:10 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Yahiaoui",
"S. -A.",
""
],
[
"Cherroud",
"O.",
""
],
[
"Bentaiba",
"M.",
""
]
] |
0705.2572 | Ajay Patwardhan | Ajay Patwardhan | Supersymmetric Yang Mills Fields and Black Holes ; In Ten Dimensional
Unified Field Theory | 8 pages, no figures, [email protected] Physics deptt, St Xavier's
college, Mumbai, India visitor, Institute of mathematical sciences, Chennai,
India | null | null | null | physics.gen-ph | null | The Ten dimensional Unified field theory has a 4 dimensional Riemannian
spacetime and six dimensional Calabi Yau space structure. The supersymmetric
Yang Mills fields and black holes are solutions in these theories. The
formation of primordial black holes in early universe, the collapse to
singularity of stellar black holes, the Hawking evaporation of microscopic
black holes in LHC are topics of observational and theoretical interest.
The observation of gamma ray bursts and creation of spectrum of particles and
radiation of dark and normal matter occur due to primordial and microscopic
black holes. The approach to singularity in black hole interior solutions,
require the Bogoliubov transforms of SUSY YM fields in black hole geometries;
both during formation and in evaporation. The Hawking effect of radiating black
holes is applicable for all the fields. Invariants can be defined to give the
conditions for these processes.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 17:47:00 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Patwardhan",
"Ajay",
""
]
] |
0705.2573 | Bertrand Reulet | J. Gabelli and B. Reulet | Dynamics of Quantum Noise in a Tunnel Junction under ac Excitation | Theory removed. More experimental details. One extra figure | Phys. Rev. Lett. 100, 026601 (2008) | 10.1103/PhysRevLett.100.026601 | null | cond-mat.mes-hall | null | We report the first measurement of the \emph{dynamical response} of shot
noise (measured at frequency $\omega$) of a tunnel junction to an ac excitation
at frequency $\omega_0$. The experiment is performed in the quantum regime,
$\hbar\omega\sim\hbar\omega_0\gg k_BT$ at very low temperature T=35mK and high
frequency $\omega_0/2\pi=6.2$ GHz. We observe that the noise responds in phase
with the excitation, but not adiabatically. The results are in very good
agreement with a prediction based on a new current-current correlator.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 17:57:19 GMT"
},
{
"version": "v2",
"created": "Thu, 25 Oct 2007 14:41:16 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Gabelli",
"J.",
""
],
[
"Reulet",
"B.",
""
]
] |
0705.2574 | Serge Repin Mr. | S. V. Repin, V. N. Lukash, V. N. Strokov | Analytical approximation of the emission line Fe $K_\alpha$ in QSO's
spectra | 20 pages, 8 figures, 2 tables | null | null | null | astro-ph | null | In spectra of many Seyfert galaxies there is a wide emission line of Fe
$K_\alpha$. The line profile with two maxima supposes that the line emerges in
innermost regions of an accretion disk around a black hole, hence, it is
necessary to take into account General Relativity (GR) effects. In order to
determine GR processes which occur in active galactic nuclei (AGN) an inverse
problem of reconstructing the accreting system parameters from the line profile
has to be solved quickly. In this paper we present a numerical approximation of
the emission line Fe $K_\alpha$ with analytical functions. The approximation is
accomplished for a range of the disk radial coordinate $r$ and the angle
$\theta$ between line of sight and perpendicular to the disk and allows one to
decrease computing time by $10^6$ times in certain astrophysical problems
taking into account all GR effects. The approximation results are available in
the Internet at http://www.iki.rssi.ru/people/repin/approx
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 17:59:39 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Repin",
"S. V.",
""
],
[
"Lukash",
"V. N.",
""
],
[
"Strokov",
"V. N.",
""
]
] |
0705.2575 | Guang-You Qin | Guang-You Qin, J\"org Ruppert, Simon Turbide, Charles Gale, Chiho
Nonaka, Steffen A. Bass | Radiative jet energy loss in a three-dimensional hydrodynamical medium
and high $p_T$ azimuthal asymmetry of $\pi_0$ suppression at mid and forward
rapidity at RHIC | published version | Phys.Rev.C76:064907,2007 | 10.1103/PhysRevC.76.064907 | null | hep-ph nucl-th | null | The nuclear modification factor $R_{AA}$ for $\pi_0$ production in Au+Au
collisions at $\sqrt{s}=200$ AGeV is calculated, and studied at high transverse
momenta $p_T$. The soft thermalized nuclear medium is described within the
framework of relativistic ideal three-dimensional hydrodynamics. The energy
loss of partonic jets is evaluated in the context of gluon bremsstrahlung in
the thermalized partonic matter. We provide a systematic analysis of the
azimuthal asymmetry of $\pi_0$ suppression at high $p_T$ in central and
non-central collisions, at mid and forward rapidity. The determination of
$R_{AA}$ as a function of $p_T$, at different azimuthal angles, and different
rapidities makes for a stringent test of our theoretical understanding of jet
energy loss over a variety of in-medium path lengths, temperatures and initial
partonic jet energies. This lays the groundwork for a precise tomography of the
nuclear medium.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 18:09:30 GMT"
},
{
"version": "v2",
"created": "Wed, 30 May 2007 19:43:35 GMT"
},
{
"version": "v3",
"created": "Wed, 16 Jan 2008 15:26:07 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Qin",
"Guang-You",
""
],
[
"Ruppert",
"Jörg",
""
],
[
"Turbide",
"Simon",
""
],
[
"Gale",
"Charles",
""
],
[
"Nonaka",
"Chiho",
""
],
[
"Bass",
"Steffen A.",
""
]
] |
0705.2576 | Michael Frank | Michael Frank and Kamran Sharifi | Adjointability of densely defined closed operators and the
Magajna-Schweizer Theorem | 13 pages | null | null | SFB 478 - Geometrical Structures in Mathematics - SFB preprint
series v. 466(2007), Univ. M | math.OA math-ph math.FA math.MP | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | In this notes unbounded regular operators on Hilbert $C^*$-modules over
arbitrary $C^*$-algebras are discussed. A densely defined operator $t$
possesses an adjoint operator if the graph of $t$ is an orthogonal summand.
Moreover, for a densely defined operator $t$ the graph of $t$ is orthogonally
complemented and the range of $P_FP_{G(t)^\bot}$ is dense in its biorthogonal
complement if and only if $t$ is regular. For a given $C^*$-algebra $\mathcal
A$ any densely defined $\mathcal A$-linear closed operator $t$ between Hilbert
$C^*$-modules is regular, if and only if any densely defined $\mathcal
A$-linear closed operator $t$ between Hilbert $C^*$-modules admits a densely
defined adjoint operator, if and only if $\mathcal A$ is a $C^*$-algebra of
compact operators. Some further characterizations of closed and regular modular
operators are obtained.
Changes 1: Improved results, corrected misprints, added references. Accepted
by J. Operator Theory, August 2007 / Changes 2: Filled gap in the proof of Thm.
3.1, changes in the formulations of Cor. 3.2 and Thm. 3.4, updated references
and address of the second author.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 18:07:27 GMT"
},
{
"version": "v2",
"created": "Wed, 29 Aug 2007 18:46:42 GMT"
},
{
"version": "v3",
"created": "Fri, 22 Jan 2010 16:55:35 GMT"
}
] | 2010-01-22T00:00:00 | [
[
"Frank",
"Michael",
""
],
[
"Sharifi",
"Kamran",
""
]
] |
0705.2577 | Christiane Quesne | Christiane Quesne | Quadratic Algebra Approach to an Exactly Solvable Position-Dependent
Mass Schr\"odinger Equation in Two Dimensions | Published in SIGMA (Symmetry, Integrability and Geometry: Methods and
Applications) at http://www.emis.de/journals/SIGMA/ | SIGMA 3 (2007), 067, 14 pages | 10.3842/SIGMA.2007.067 | null | math-ph math.MP nlin.SI quant-ph | null | An exactly solvable position-dependent mass Schr\"odinger equation in two
dimensions, depicting a particle moving in a semi-infinite layer, is
re-examined in the light of recent theories describing superintegrable
two-dimensional systems with integrals of motion that are quadratic functions
of the momenta. To get the energy spectrum a quadratic algebra approach is used
together with a realization in terms of deformed parafermionic oscillator
operators. In this process, the importance of supplementing algebraic
considerations with a proper treatment of boundary conditions for selecting
physical wavefunctions is stressed. Some new results for matrix elements are
derived. This example emphasizes the interest of a quadratic algebra approach
to position-dependent mass Schr\"odinger equations.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 18:11:14 GMT"
}
] | 2008-04-24T00:00:00 | [
[
"Quesne",
"Christiane",
""
]
] |
0705.2578 | Thomas Schick | Bernhard Hanke (Ludwig-Maximilian Universitaet Muenchen), Thomas
Schick (Georg-August-Universitaet Goettingen) | The strong Novikov conjecture for low degree cohomology | 11 pages | Geom Dedicata (2008) 135:119-127 | 10.1007/s10711-008-9266-9 | null | math.KT math.GT | null | We show that for each discrete group G, the rational assembly map
K_*(BG) \otimes Q \to K_*(C*_{max} G) \otimes \Q is injective on classes dual
to the subring generated by cohomology classes of degree at most 2 (identifying
rational K-homology and homology via the Chern character). Our result implies
homotopy invariance of higher signatures associated to these cohomology
classes. This consequence was first established by Connes-Gromov-Moscovici and
Mathai.
Our approach is based on the construction of flat twisting bundles out of
sequences of almost flat bundles as first described in our previous work. In
contrast to the argument of Mathai, our approach is independent of (and indeed
gives a new proof of) the result of Hilsum-Skandalis on the homotopy invariance
of the index of the signature operator twisted with bundles of small curvature.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 18:18:55 GMT"
}
] | 2008-08-21T00:00:00 | [
[
"Hanke",
"Bernhard",
"",
"Ludwig-Maximilian Universitaet Muenchen"
],
[
"Schick",
"Thomas",
"",
"Georg-August-Universitaet Goettingen"
]
] |
0705.2579 | Li Zhang | Ryan Tu, Li Zhang, Yoshio Nishi, and Hongjie Dai | Measuring the Capacitance of Individual Semiconductor Nanowires for
Carrier Mobility Assessment | null | null | 10.1021/nl070378w | null | cond-mat.mtrl-sci | null | Capacitance-voltage characteristics of individual germanium nanowire field
effect transistors were directly measured and used to assess carrier mobility
in nanowires for the first time; thereby removing uncertainties in calculated
mobility due to device geometries, surface and interface states and gate
dielectric constants and thicknesses. Direct experimental evidence showed that
surround-gated nanowire transistors exhibit higher capacitance and better
electrostatic gate control than top-gated devices, and are the most promising
structure for future high performance nanoelectronics.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 18:27:03 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Tu",
"Ryan",
""
],
[
"Zhang",
"Li",
""
],
[
"Nishi",
"Yoshio",
""
],
[
"Dai",
"Hongjie",
""
]
] |
0705.2580 | Rubens Ramos Viana | Jose Claudio do Nascimento and Rubens Viana Ramos | Quantum protocols for transference of proof of zero-knowledge systems | 4 pages | null | null | null | quant-ph | null | Zero-knowledge proof system is an important protocol that can be used as a
basic block for construction of other more complex cryptographic protocols. An
intrinsic characteristic of a zero-knowledge systems is the assumption that is
impossible for the verifier to show to a third part that he has interacted with
the prover. However, it has been shown that using quantum correlations the
impossibility of transferring proofs can be successfully attacked. In this work
we show two new protocols for proof transference, being the first one based on
teleportation and the second one without using entangled states.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 18:30:02 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Nascimento",
"Jose Claudio do",
""
],
[
"Ramos",
"Rubens Viana",
""
]
] |
0705.2581 | Maurice Duval | Maurice Duval | Un Resultat Gravimetrique pour la Renaissance de la Theorie
Corpusculaire "An Experimental Gravimetric Result for the Revival of
Corpuscular Theory" | 16 pages in French, annex 3 pages in English "For paper in English,
see http://www.physicsessays.com/catalog.asp" | Phys.Essays18:53-62,2005 | 10.4006/1.3025724 | null | physics.gen-ph | null | The gravitational phenomenon, founded on the assumption of absorption of a
flux of gravitons through the matter, led to a law of attraction comprising a
term of attenuation of gravity. The attenuation effect, which depends on the
distribution of mass elements into the Sun, was compared with the relativistic
effect for the orbital elements of planets. The calculations carried out with
our modified law of Newton, lead to a perfect agreement for the advance of the
perihelion of planets, and give an interaction cross section with the matter of
3.2x10^-17 m2/kg (approximately 10^-40 cm2/nucleon). The effect of attenuation
during a solar eclipse will produce a local reduction in the soli-lunar
attraction of 0.13 microgal. This small variation of gravity during the eclipse
can lead to distortions of the geoid of about ten millimetres of which effect
on gravity, estimated at a few microgals, is compatible with the observed
gravitational anomalies. The gravimetric measurements taken in the area of
Montreal during the Sun eclipse of May 10, 1994, show the existence of an
anomaly of 2.4 microgals that coincides perfectly with the period of the
eclipse.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 18:32:51 GMT"
}
] | 2015-05-13T00:00:00 | [
[
"Duval",
"Maurice",
""
]
] |
0705.2582 | Patrick Godon | Dinshaw S. Balsara, Jacob Lund Fisker, Patrick Godon, Edward M. Sion | Simulations of the Boundary Layer Between a White Dwarf and its
Accretion Disk | final version, ApJ, in press | Astrophys.J.702:1536-1552,2009 | 10.1088/0004-637X/702/2/1536 | null | astro-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Using a 2.5D time-dependent axisymmetric numerical code we recently
developed, we solve the full compressible Navier-Stokes equations (including an
alpha-viscosity prescription) to determine the structure of the boundary layer
between the white dwarf and the accretion disk in non-magnetic cataclysmic
varia ble systems. In this preliminary work, our numerical approach does not
include radiation. In the energy equation, we either take the dissipation
function (Phi) into account or we assumed that the energy is instantly radiated
away (Phi). For a slowly rotating non magnetized accreting white dwarf, the
accretion disk e xtends all the way to the stellar surface. There, the matter
impacts and spread s towards the poles as new matter continuously piles up
behind it. We carried out numerical simulations for different values of the
alpha viscosity parameter (alpha), corresponding to different mass accretion
rates. In the high viscosity cases (alpha=0.1), the spreading boundary layer
sets off a gravity wave in the s urface matter. The accretion flow moves
supersonically over the cusp making it s usceptible to the rapid development of
gravity wave and/or Kelvin-Helmholtz shea ring instabilities. This BL is
optically thick and extends more than 30 degrees to either side of the disk
plane after only 3/4 of a Keplerian rotation period (19s). In the low viscosity
cases (alpha=0.001), the spreading boundary layer does not set off gravity
waves and it is optically thin.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 18:43:12 GMT"
},
{
"version": "v2",
"created": "Tue, 1 Apr 2008 18:54:40 GMT"
},
{
"version": "v3",
"created": "Thu, 9 Jul 2009 19:40:45 GMT"
}
] | 2009-09-28T00:00:00 | [
[
"Balsara",
"Dinshaw S.",
""
],
[
"Fisker",
"Jacob Lund",
""
],
[
"Godon",
"Patrick",
""
],
[
"Sion",
"Edward M.",
""
]
] |
0705.2583 | Julio de Vicente | Julio I. de Vicente | Further results on entanglement detection and quantification from the
correlation matrix criterion | 13 pages, no figures; added references, minor changes; section 4.3
added, to appear in J. Phys. A | J. Phys. A: Math. Theor. 41, 065309 (2008) | 10.1088/1751-8113/41/6/065309 | null | quant-ph | null | The correlation matrix (CM) criterion is a recently derived powerful
sufficient condition for the presence of entanglement in bipartite quantum
states of arbitrary dimensions. It has been shown that it can be stronger than
the positive partial transpose (PPT) criterion, as well as the computable cross
norm or realignment (CCNR) criterion in different situations. However, it
remained as an open question whether there existed sets of states for which the
CM criterion could be stronger than both criteria simultaneously. Here, we give
an affirmative answer to this question by providing examples of entangled
states that scape detection by both the PPT and CCNR criteria whose
entanglement is revealed by the CM condition. We also show that the CM can be
used to measure the entanglement of pure states and obtain lower bounds for the
entanglement measure known as tangle for general (mixed) states.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 18:44:02 GMT"
},
{
"version": "v2",
"created": "Tue, 29 May 2007 11:28:35 GMT"
},
{
"version": "v3",
"created": "Thu, 10 Jan 2008 14:22:30 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"de Vicente",
"Julio I.",
""
]
] |
0705.2584 | Zoltan Haiman | Cien Shang, Arlin Crotts, Zolt\'an Haiman (Columbia University) | Constraints on the Abundance of Highly Ionized Proto-Cluster Regions
from the Absence of Large Voids in the Lyman Alpha Forest | submitted to ApJ, 9 emulateapj pages with 3 figures | 2007, ApJ, 671, 136-145 | 10.1086/522331 | null | astro-ph | null | Energetic feedback processes during the formation of galaxy clusters may have
heated and ionized a large fraction of the intergalactic gas in proto-cluster
regions. When such a highly ionized hot ``super-bubble'' falls along the
sightline to a background quasar, it would be seen as a large void, with little
or no absorption, in the Lyman alpha forest. We examine the spectra of 137
quasars in the Sloan Digital Sky Survey, to search for such voids, and find no
clear evidence of their existence. The size distribution of voids in the range
5-70 Angstrom (corresponding to physical sizes of approximately 3-35 comoving
Mpc/h) is consistent with the standard model for the Lyman alpha forest without
additional hot bubbles. We adapt a physical model for HII bubble growth during
cosmological reionization (Furlanetto, Zaldarriaga and Hernquist 2004), to
describe the expected size-distribution of hot super-bubbles at redshift around
z = 3. This model incorporates the conjoining of bubbles around individual
neighboring galaxies. Using the non-detection of voids, we find that models in
which the volume filling factor of hot bubbles exceeds approximately 20 percent
at z=3 can be ruled out, primarily because they overproduce the number of large
(40-50 Angstrom) voids. We conclude that any pre-heating mechanism that
explains galaxy cluster observations must avoid heating the low-density gas in
the proto-cluster regions, either by operating relatively recently (z<3) or by
depositing entropy in the high-density regions.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 18:53:36 GMT"
}
] | 2009-06-25T00:00:00 | [
[
"Shang",
"Cien",
"",
"Columbia University"
],
[
"Crotts",
"Arlin",
"",
"Columbia University"
],
[
"Haiman",
"Zoltán",
"",
"Columbia University"
]
] |
0705.2585 | Zahid Zakir | Zahid Zakir (CTPA) | General Relativity Constraints the Proper Times and Predicts the Frozen
Stars Instead of the Black Holes | 10 pages. Submitted to Phys. Lett. B. Reviesed version | Theor. Phys., Astrophys. and Cosmol., 2 (2007) 1 | 10.9751/TPAC.2497-006 | CTPA-07-01 | physics.gen-ph | null | In a static gravitational field an intersection of a worldline by a global
hypersurface of simultaneity t=const gives an invariant constraint relating the
proper time of this event by t. Since at any finite t the such constrained
proper time intervals are less than reqiured for crossing a horizon, general
relativity predicts the gravitational freezing of proper times in stars with
time-like or null geodesics everywhere. The time dilation stabilizes
contracting massive stars by freezing, which is maximal but finite at the
centre, and the surface is frozen near the gravitational radius. The frozen
stars (frozars) slowly defrost due to emissions and external interactions, the
internal phase transitions can initiate refreezing with bursts and explosions.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 19:01:50 GMT"
},
{
"version": "v2",
"created": "Thu, 7 Jun 2007 05:32:58 GMT"
}
] | 2012-10-09T00:00:00 | [
[
"Zakir",
"Zahid",
"",
"CTPA"
]
] |
0705.2586 | Dmitrii L. Maslov | Vladimir I. Yudson and Dmitrii L. Maslov | Universality in scattering by large-scale potential fluctuations in
two-dimensional conductors | 4 pages, 3 figures, submitted to PRB | Phys. Rev. B v. 75, 241408 (2007) | 10.1103/PhysRevB.75.241408 | null | cond-mat.mes-hall | null | We study electron propagation through a random array of rare, opaque and
large (compared the de Broglie wavelength of electrons) scatterers. It is shown
that for any convex scatterer the ratio of the transport to quantum lifetimes
\eta=\tau_{tr}/\tau_{tot}$ does not depend on the shape of the scatterer but
only on whether scattering is specular or diffuse and on the spatial
dimensionality (D). In particular, for specular scattering, \eta is a universal
constant determined only by the dimensionality of the system: \eta = 2 for D =
3 and \eta = 3/2 for D = 2. The crossover between classical and quantum regimes
of scattering is discussed.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 19:05:15 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Yudson",
"Vladimir I.",
""
],
[
"Maslov",
"Dmitrii L.",
""
]
] |
0705.2587 | Ludovic Bonneau M | L. Bonneau, J. Bartel and P. Quentin | Isospin mixing in a particle-number conserving microscopic approach | 13 pages, 7 figures, 3 tables; submitted to Physical Review C | null | null | LAUR 07-3253 | nucl-th | null | We calculate the isospin-mixing parameter for several Tz=-1, Tz=0 and Tz=1
nuclei from Mg to Sn in the particle-number conserving Higher Tamm-Dancoff
approach taking into account the pairing correlations. In particular we
investigate the role of the Coulomb interaction and the |Tz|=1 pairing
correlations. To do so the HTDA approach is implemented with the SIII Skyrme
effective nucleon-nucleon interaction in the mean-field channel and a delta
interaction in the pairing channel. We conclude from this investigation that
the pairing correlations bring a large contribution to isospin-symmetry
breaking, whereas the Coulomb interaction turns out to play a less important
role. Moreover we find that the isospin-mixing parameters for Tz=-1 and Tz=1
nuclei are comparable while they are about twice as large for Tz=0 nuclei
(between 3% and 6%, including doubly magic nuclei).
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 19:15:10 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Bonneau",
"L.",
""
],
[
"Bartel",
"J.",
""
],
[
"Quentin",
"P.",
""
]
] |
0705.2588 | Shin'ichiro Ando | Shin'ichiro Ando, Daisuke Nagai (Caltech) | Gamma-ray probe of cosmic-ray pressure in galaxy clusters and
cosmological implications | 12 pages, 5 figures; extended discussions; accepted by MNRAS | Mon.Not.Roy.Astron.Soc.385:2243-2253, 2008 | 10.1111/j.1365-2966.2008.12996.x | null | astro-ph | null | Cosmic rays produced in cluster accretion and merger shocks provide pressure
to the intracluster medium (ICM) and affect the mass estimates of galaxy
clusters. Although direct evidence for cosmic-ray ions in the ICM is still
lacking, they produce gamma-ray emission through the decay of neutral pions
produced in their collisions with ICM nucleons. We investigate the capability
of the Gamma-ray Large Area Space Telescope (GLAST) and imaging atmospheric
Cerenkov telescopes (IACTs) for constraining the cosmic-ray pressure
contribution to the ICM. We show that GLAST can be used to place stringent
upper limits, a few per cent for individual nearby rich clusters, on the ratio
of pressures of the cosmic rays and thermal gas. We further show that it is
possible to place tight (<~10%) constraints for distant (z <~ 0.25) clusters in
the case of hard spectrum, by stacking signals from samples of known clusters.
The GLAST limits could be made more precise with the constraint on the
cosmic-ray spectrum potentially provided by IACTs. Future gamma-ray
observations of clusters can constrain the evolution of cosmic-ray energy
density, which would have important implications for cosmological tests with
upcoming X-ray and Sunyaev-Zel'dovich effect cluster surveys.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 19:51:13 GMT"
},
{
"version": "v2",
"created": "Mon, 21 Jan 2008 17:58:56 GMT"
}
] | 2011-02-11T00:00:00 | [
[
"Ando",
"Shin'ichiro",
"",
"Caltech"
],
[
"Nagai",
"Daisuke",
"",
"Caltech"
]
] |
0705.2589 | Peter W. Gorham | P. W. Gorham, N. G. Lehtinen, G. S. Varner, J. J. Beatty, A. Connolly,
P. Chen, M. E. Conde, W. Gai, C. Hast, C. L. Hebert, C. Miki, R. Konecny, J.
Kowalski, J. Ng, J. G. Power, K. Reil, D. Saltzberg, B. T. Stokes, and D.
Walz | Observations of Microwave Continuum Emission from Air Shower Plasmas | 15 pages, 13 figures | Phys.Rev.D78:032007,2008 | 10.1103/PhysRevD.78.032007 | null | astro-ph | null | We investigate a possible new technique for microwave measurements of
ultra-high energy cosmic ray (UHECR) extensive air showers which relies on
detection of expected continuum radiation in the microwave range, caused by
free-electron collisions with neutrals in the tenuous plasma left after the
passage of the shower. We performed an initial experiment at the AWA (Argonne
Wakefield Accelerator) laboratory in 2003 and measured broadband microwave
emission from air ionized via high energy electrons and photons. A follow-up
experiment at SLAC (Stanford Linear Accelerator Center) in summer of 2004
confirmed the major features of the previous AWA observations with better
precision and made additional measurements relevant to the calorimetric
capabilities of the method. Prompted by these results we built a prototype
detector using satellite television technology, and have made measurements
indicating possible detection of cosmic ray extensive air showers. The method,
if confirmed by experiments now in progress, could provide a high-duty cycle
complement to current nitrogen fluorescence observations of UHECR, which are
limited to dark, clear nights. By contrast, decimeter microwave observations
can be made both night and day, in clear or cloudy weather, or even in the
presence of moderate precipitation.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 20:23:11 GMT"
}
] | 2009-09-29T00:00:00 | [
[
"Gorham",
"P. W.",
""
],
[
"Lehtinen",
"N. G.",
""
],
[
"Varner",
"G. S.",
""
],
[
"Beatty",
"J. J.",
""
],
[
"Connolly",
"A.",
""
],
[
"Chen",
"P.",
""
],
[
"Conde",
"M. E.",
""
],
[
"Gai",
"W.",
""
],
[
"Hast",
"C.",
""
],
[
"Hebert",
"C. L.",
""
],
[
"Miki",
"C.",
""
],
[
"Konecny",
"R.",
""
],
[
"Kowalski",
"J.",
""
],
[
"Ng",
"J.",
""
],
[
"Power",
"J. G.",
""
],
[
"Reil",
"K.",
""
],
[
"Saltzberg",
"D.",
""
],
[
"Stokes",
"B. T.",
""
],
[
"Walz",
"D.",
""
]
] |
0705.2590 | David R. Ballantyne | D.R. Ballantyne (1), F. Ozel (1) and D. Psaltis (1,2) ((1) Dept. of
Physics, Univ. of Arizona, (2) Dept. of Astronomy, Univ. of Arizona) | Constraining Radiatively Inefficient Accretion Flows with Polarization | 4 pages, 3 figures, accepted by ApJ Letters | null | 10.1086/519951 | null | astro-ph | null | The low-luminosity black hole Sgr A* provides a testbed for models of
Radiatively Inefficient Accretion Flows (RIAFs). Recent sub-millimeter linear
polarization measurements of Sgr A* have provided evidence that the electrons
in the accretion flow are relativistic over a large range of radii. Here, we
show that these high temperatures result in elliptical plasma normal modes.
Thus, polarized millimeter and sub-millimeter radiation emitted within RIAFs
will undergo generalized Faraday rotation, a cyclic conversion between linear
and circular polarization. This effect will not depolarize the radiation even
if the rotation measure is extremely high. Rather, the beam will take on the
linear and circular polarization properties of the plasma normal modes. As a
result, polarization measurements of Sgr A* in this frequency regime will
constrain the temperature, density and magnetic profiles of RIAF models.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 20:08:14 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Ballantyne",
"D. R.",
""
],
[
"Ozel",
"F.",
""
],
[
"Psaltis",
"D.",
""
]
] |
0705.2591 | Marcos Rigol Madrazo | Marcos Rigol and Rajiv R. P. Singh | Kagome lattice antiferromagnets and Dzyaloshinsky-Moriya interactions | 12 pages, 15 figures. Content, references, and comments on recent
experiments have been added. Published version | Phys. Rev. B 76, 184403 (2007) | 10.1103/PhysRevB.76.184403 | null | cond-mat.str-el | null | We study the consequences of in-plane (D_p) and out-of-plane (D_z)
Dzyaloshinsky-Moriya (DM) interactions on the thermodynamic properties of
spin-1/2} Heisenberg model on the kagome lattice using numerical linked cluster
expansions and exact diagonalization, and contrast them with those of other
perturbations such as exchange anisotropy and dilution. We find that different
combinations of the DM anisotropies lead to a wide variety of thermodynamic
behavior, which are quite distinct from those of most other perturbations. We
argue that the sudden upturn seen experimentally in the susceptibility of the
material ZnCu3(OH)6Cl2 can be understood in terms of Dzyaloshinsky-Moriya
anisotropies with D_p>|D_z|. We also show that the measured specific heat of
the material puts further constraints on the allowed DM parameters.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 20:00:08 GMT"
},
{
"version": "v2",
"created": "Fri, 2 Nov 2007 20:18:47 GMT"
}
] | 2011-11-09T00:00:00 | [
[
"Rigol",
"Marcos",
""
],
[
"Singh",
"Rajiv R. P.",
""
]
] |
0705.2592 | Johnpierre Paglione | Johnpierre Paglione, T. A. Sayles, P.-C. Ho, J. R. Jeffries, M. B.
Maple | Incoherent non-Fermi liquid scattering in a Kondo lattice | 4 pages, 3 figures (published version) | Nature Physics 3, 703 (2007) | 10.1038/nphys711 | null | cond-mat.str-el cond-mat.supr-con | null | One of the most notorious non-Fermi liquid properties of both archetypal
heavy-fermion systems [1-4] and the high-Tc copper oxide superconductors [5] is
an electrical resistivity that evolves linearly with temperature, T. In the
heavy-fermion superconductor CeCoIn5 [5], this linear behaviour was one of the
first indications of the presence of a zero-temperature instability, or quantum
critical point. Here, we report the observation of a unique control parameter
of T-linear scattering in CeCoIn5, found through systematic chemical
substitutions of both magnetic and non-magnetic rare-earth, R, ions into the Ce
sub-lattice. We find that the evolution of inelastic scattering in Ce1-xRxCoIn5
is strongly dependent on the f-electron configuration of the R ion, whereas two
other key properties -- Cooper-pair breaking and Kondo-lattice coherence -- are
not. Thus, T-linear resistivity in CeCoIn5 is intimately related to the nature
of incoherent scattering centers in the Kondo lattice, which provides insight
into the anomalous scattering rate synonymous with quantum criticality [7].
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 20:01:15 GMT"
},
{
"version": "v2",
"created": "Tue, 18 Mar 2008 21:54:04 GMT"
}
] | 2008-03-19T00:00:00 | [
[
"Paglione",
"Johnpierre",
""
],
[
"Sayles",
"T. A.",
""
],
[
"Ho",
"P. -C.",
""
],
[
"Jeffries",
"J. R.",
""
],
[
"Maple",
"M. B.",
""
]
] |
0705.2593 | Olga Norniella | Olga Norniella | Inclusive Jet Cross-section measurement at CDF | To appear in the proceedings of 42st Rencontres de Moriond on QCD and
Hadronic interactions, La Thuile, Aosta Valley, Italy, 17-24 Mar 2007 | null | null | null | hep-ex | null | Results on inclusive jet production in proton-antiproton collisions at
sqrt(s) =1.96 TeV based on 1 fb-1 of CDF Run II data are presented.
Measurements are preformed using the k_T algorithm in a wide range of jet
transverse momentum and jet rapidity. The measured cross sections are compared
to next-to-leading order perturbative QCD calculations.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 20:01:31 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Norniella",
"Olga",
""
]
] |
0705.2594 | Tibor Antal | Tibor Antal, P. L. Krapivsky, and Kirone Mallick | Molecular Spiders in One Dimension | 14 pages, 2 figures | Journal of Statistical Mechanics P08027 (2007) | 10.1088/1742-5468/2007/08/P08027 | null | cond-mat.stat-mech math.PR q-bio.QM | null | Molecular spiders are synthetic bio-molecular systems which have "legs" made
of short single-stranded segments of DNA. Spiders move on a surface covered
with single-stranded DNA segments complementary to legs. Different mappings are
established between various models of spiders and simple exclusion processes.
For spiders with simple gait and varying number of legs we compute the
diffusion coefficient; when the hopping is biased we also compute their
velocity.
| [
{
"version": "v1",
"created": "Fri, 18 May 2007 19:52:35 GMT"
}
] | 2007-08-25T00:00:00 | [
[
"Antal",
"Tibor",
""
],
[
"Krapivsky",
"P. L.",
""
],
[
"Mallick",
"Kirone",
""
]
] |
0705.2595 | Joachim Kopp | Joachim Kopp and Manfred Lindner | Detecting atmospheric neutrino oscillations in the ATLAS detector at
CERN | 8 pages, 4 figures, 2 tables, RevTeX 4; modified treatment of upward
going muons, results unchanged; matches published version | Phys.Rev.D76:093003,2007 | 10.1103/PhysRevD.76.093003 | null | hep-ph hep-ex | null | We discuss the possibility to study oscillations of atmospheric neutrinos in
the ATLAS experiment at CERN. Due to the large total detector mass, a
significant number of events is expected, and during the shutdown phases of the
LHC, reconstruction of these events will be possible with very good energy and
angular resolutions, and with charge identification. We argue that 500 live
days of neutrino running could be achieved, and that a total of ~160 contained
\nu_\mu events and ~360 upward going muons could be collected during this time.
Despite the low statistics, the excellent detector resolution will allow for an
unambiguous confirmation of atmospheric neutrino oscillations and for
measurements of the leading oscillation parameters. Though our detailed
simulations show that the sensitivity of ATLAS is worse than that of dedicated
neutrino experiments, we demonstrate that more sophisticated detectors, e.g. at
the ILC, could be highly competitive with upcoming superbeam experiments, and
might even give indications for the mass hierarchy and for the value of
theta-13.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 20:44:18 GMT"
},
{
"version": "v2",
"created": "Fri, 16 Nov 2007 08:57:42 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Kopp",
"Joachim",
""
],
[
"Lindner",
"Manfred",
""
]
] |
0705.2596 | Tibor Antal | Tibor Antal and P. L. Krapivsky | Molecular Spiders with Memory | 10 pages, 3 figures | Physical Review E 76, 021121 (2007) | 10.1103/PhysRevE.76.021121 | null | cond-mat.stat-mech math.PR q-bio.QM | null | Synthetic bio-molecular spiders with "legs" made of single-stranded segments
of DNA can move on a surface which is also covered by single-stranded segments
of DNA complementary to the leg DNA. In experimental realizations, when a leg
detaches from a segment of the surface for the first time it alters that
segment, and legs subsequently bound to these altered segments more weakly.
Inspired by these experiments we investigate spiders moving along a
one-dimensional substrate, whose legs leave newly visited sites at a slower
rate than revisited sites. For a random walk (one-leg spider) the slowdown does
not effect the long time behavior. For a bipedal spider, however, the slowdown
generates an effective bias towards unvisited sites, and the spider behaves
similarly to the excited walk. Surprisingly, the slowing down of the spider at
new sites increases the diffusion coefficient and accelerates the growth of the
number of visited sites.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 20:12:44 GMT"
}
] | 2007-08-25T00:00:00 | [
[
"Antal",
"Tibor",
""
],
[
"Krapivsky",
"P. L.",
""
]
] |
0705.2597 | Gorchinskiy Sergey | Sergey Gorchinskiy | Adelic resolution for homology sheaves | 64 pages | Izv. Math., 72, no. 6 (2008), 1187-1252 | 10.1070/IM2008v072n06ABEH002433 | null | math.AG math.KT | null | A generalization of the usual ideles group is proposed, namely, we construct
certain adelic complexes for sheaves of $K$-groups on schemes. More generally,
such complexes are defined for any abelian sheaf on a scheme. We focus on the
case when the sheaf is associated to the presheaf of a homology theory with
certain natural axioms, satisfied by $K$-theory. In this case it is proven that
the adelic complex provides a flasque resolution for the above sheaf and that
the natural morphism to the Gersten complex is a quasiisomorphism. The main
advantage of the new adelic resolution is that it is contravariant and
multiplicative in contrast to the Gersten resolution. In particular, this
allows to reprove that the intersection in Chow groups coincides up to sign
with the natural product in the corresponding $K$-cohomology groups. Also, we
show that the Weil pairing can be expressed as a Massey triple product in
$K$-cohomology groups with certain indices.
| [
{
"version": "v1",
"created": "Thu, 17 May 2007 20:38:03 GMT"
},
{
"version": "v2",
"created": "Mon, 11 Feb 2008 13:31:17 GMT"
}
] | 2015-05-13T00:00:00 | [
[
"Gorchinskiy",
"Sergey",
""
]
] |
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