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list | update_date
timestamp[s] | authors_parsed
sequence |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
0704.3201 | Grigoris Panotopoulos | Grigoris Panotopoulos | Assisted chaotic inflation in brane-world cosmology | Revtex, 4 pages, accepted for publication in Phys.Rev.D | Phys.Rev.D75:107302,2007 | 10.1103/PhysRevD.75.107302 | null | hep-ph | null | Assisted chaotic inflation in brane cosmology is discussed. We work in the
framework of Randall-Sundrum (RS) II model, in which adopting the RS condition
the only parameter is the five-dimensional Planck mass. Using the scalar
spectral index and the amplitude of scalar perturbations we determine both the
mass of the scalar fields responsible for inflation and the fundamental Planck
mass of the higher-dimensional theory. We find that the mass of the scalars has
the typical value of the inflaton mass in chaotic inflation ($M_I \sim 10^{13}$
GeV) and that the five-dimensional Planck mass is very close to the GUT (Grand
Unified Theories) scale ($M_5 \sim (10^{16}-10^{17})$ GeV). Furthermore, no
matter how many scalar fields we use it is not possible to have chaotic
inflation with field values below the fundamental Planck mass.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 14:37:15 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Panotopoulos",
"Grigoris",
""
]
] |
0704.3202 | Mark Thompson | M.A. Thompson, S. Serjeant, T. Jenness, D. Scott, M. Ashdown, C.
Brunt, H. Butner, E. Chapin, A. C. Chrysostomou, J. S. Clark, D. Clements, J.
L. Collett, K. Coppin, I. M. Coulson, W. R. F. Dent, F. Economou, A. Evans,
P. Friberg, G. A. Fuller, A. G. Gibb, J. Greaves, J. Hatchell, W. S. Holland,
M. Hudson, R. J. Ivison, A. Jaffe, G. Joncas, H. R. A. Jones, J. H. Knapen,
J. Leech, R. Mann, H. E. Matthews, T. J. T. Moore, A. Mortier, M. Negrello,
D. Nutter, M. P. Pestalozzi, A. Pope, J. Richer, R. Shipman, J. S. Urquhart,
M. Vaccari, L. Van Waerbeke, S. Viti, B. Weferling, G. J. White, J.
Wouterloot, M. Zhu | The SCUBA-2 "All-Sky" Survey | 26 pages, 5 figures. In referee's format. Submitted to PASP. Figs 1-3
are missing due to file size constraints. A full version of the paper may be
found at http://star-www.herts.ac.uk/~mat/sassy_pasp.pdf Version 2 fixes
author list and link to full version of paper | null | null | null | astro-ph | null | The sub-millimetre wavelength regime is perhaps the most poorly explored over
large areas of the sky, despite the considerable effort that has been expended
in making deep maps over small regions. As a consequence the properties of the
sub-millimetre sky as a whole, and of rare bright objects in particular,
remains largely unknown. Here we describe a forthcoming survey (the SCUBA-2
``All-Sky'' Survey, or SASSy) designed to address this issue by making a
large-area map of approximately one-fifth of the sky visible from the JCMT
(4800 square degrees) down to a 1 sigma noise level of 30 mJy/beam. This map
forms the pilot for a much larger survey, which will potentially map the
remaining sky visible from the JCMT, with the region also visible to ALMA as a
priority. SASSy has been awarded 500 hours for the 4800 square degree pilot
phase and will commence after the commissioning of SCUBA-2, expected in early
2008.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 14:25:10 GMT"
},
{
"version": "v2",
"created": "Wed, 2 May 2007 22:01:26 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Thompson",
"M. A.",
""
],
[
"Serjeant",
"S.",
""
],
[
"Jenness",
"T.",
""
],
[
"Scott",
"D.",
""
],
[
"Ashdown",
"M.",
""
],
[
"Brunt",
"C.",
""
],
[
"Butner",
"H.",
""
],
[
"Chapin",
"E.",
""
],
[
"Chrysostomou",
"A. C.",
""
],
[
"Clark",
"J. S.",
""
],
[
"Clements",
"D.",
""
],
[
"Collett",
"J. L.",
""
],
[
"Coppin",
"K.",
""
],
[
"Coulson",
"I. M.",
""
],
[
"Dent",
"W. R. F.",
""
],
[
"Economou",
"F.",
""
],
[
"Evans",
"A.",
""
],
[
"Friberg",
"P.",
""
],
[
"Fuller",
"G. A.",
""
],
[
"Gibb",
"A. G.",
""
],
[
"Greaves",
"J.",
""
],
[
"Hatchell",
"J.",
""
],
[
"Holland",
"W. S.",
""
],
[
"Hudson",
"M.",
""
],
[
"Ivison",
"R. J.",
""
],
[
"Jaffe",
"A.",
""
],
[
"Joncas",
"G.",
""
],
[
"Jones",
"H. R. A.",
""
],
[
"Knapen",
"J. H.",
""
],
[
"Leech",
"J.",
""
],
[
"Mann",
"R.",
""
],
[
"Matthews",
"H. E.",
""
],
[
"Moore",
"T. J. T.",
""
],
[
"Mortier",
"A.",
""
],
[
"Negrello",
"M.",
""
],
[
"Nutter",
"D.",
""
],
[
"Pestalozzi",
"M. P.",
""
],
[
"Pope",
"A.",
""
],
[
"Richer",
"J.",
""
],
[
"Shipman",
"R.",
""
],
[
"Urquhart",
"J. S.",
""
],
[
"Vaccari",
"M.",
""
],
[
"Van Waerbeke",
"L.",
""
],
[
"Viti",
"S.",
""
],
[
"Weferling",
"B.",
""
],
[
"White",
"G. J.",
""
],
[
"Wouterloot",
"J.",
""
],
[
"Zhu",
"M.",
""
]
] |
0704.3203 | Carlos Rom\'an-Z\'u\~niga | C. Rom\'an-Z\'u\~niga, C. Lada, A. Muench, and J. Alves | The Infrared Extinction Law at Extreme Depth in a Dark Cloud Core | 22 pages manuscript, 4 figures (2 multipart), 1 table | null | 10.1086/518928 | null | astro-ph | null | We combined sensitive near-infrared data obtained with ground-based imagers
on the ESO NTT and VLT telescopes with space mid-infrared data acquired with
the IRAC imager on the Spitzer Space Telescope to calculate the extinction law
A_\lambda/A_K as a function of \lambda between 1.25 and 7.76 micron to an
unprecedented depth in Barnard 59, a star forming, dense core located in the
Pipe Nebula. The ratios A_\lambda/A_K were calculated from the slopes of the
distributions of sources in color-color diagrams \lambda-K vs. H-K. The
distributions in the color-color diagrams are fit well with single slopes to
extinction levels of A_K ~ 7 (A_V ~ 59 mag). Consequently, there appears to be
no significant variation of the extinction law with depth through the B59 line
of sight. However, when slopes are translated into the relative extinction
coefficients A_\lambda/A_K, we find an extinction law which departs from the
simple extrapolation of the near-infrared power law extinction curve, and
agrees more closely with a dust extinction model for a cloud with a total to
selective absorption R_V=5.5 and a grain size distribution favoring larger
grains than those in the diffuse ISM. Thus, the difference we observe could be
possibly due to the effect of grain growth in denser regions. Finally, the
slopes in our diagrams are somewhat less steep than those from the study of
Indebetouw et al. (2005) for clouds with lower column densities, and this
indicates that the extinction law between 3 and 8 micron might vary slightly as
a function of environment.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 15:01:09 GMT"
}
] | 2015-05-13T00:00:00 | [
[
"Román-Zúñiga",
"C.",
""
],
[
"Lada",
"C.",
""
],
[
"Muench",
"A.",
""
],
[
"Alves",
"J.",
""
]
] |
0704.3204 | John Wisniewski | John P. Wisniewski (1), Karen S. Bjorkman (2), Antonio M. Magalhaes
(3), and Antonio Pereyra (3); ((1) NASA GSFC; (2) University of Toledo; (3)
University of Sao Paulo) | The Magnetic Field Structure of the LMC 2 Supershell: NGC 2100 | 12 pages, accepted by ApJ, emulateapj5 format, full-resolution
figures available upon request ([email protected]) | null | 10.1086/519155 | null | astro-ph | null | We present U,B,V,R,I imaging polarimetry of NGC 2100 and its surrounding
environment, which comprise a part of the LMC 2 supershell. The morphology of
the observed position angle distribution provides a tracer of the projected
magnetic field in this environment. Our polarization maps detail regions
exhibiting similarly aligned polarization position angles, as well as more
complex position angle patterns. We observe regions of coherent fields on
spatial scales of 42 x 24 pc to 104 x 83 pc, and infer projected field
strengths of $\sim14-30\mu$G. We propose that the superposition of global
outflows from the LMC 2 environment, as well as outflows created within NGC
2100, produce the unique field geometry in the region.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 15:04:49 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Wisniewski",
"John P.",
""
],
[
"Bjorkman",
"Karen S.",
""
],
[
"Magalhaes",
"Antonio M.",
""
],
[
"Pereyra",
"Antonio",
""
],
[
";",
"",
""
]
] |
0704.3205 | Falk Neugebohrn | Falk Neugebohrn | Renormalization and Effective Actions for General Relativity | PhD thesis, 155 pages | null | null | null | hep-th | null | Quantum gravity is analyzed from the viewpoint of the renormalization group.
The analysis is based on methods introduced by J. Polchinski concerning the
perturbative renormalization with flow equations. In the first part of this
work, the program of renormalization with flow equations is reviewed and then
extended to effective field theories that have a finite UV cutoff. This is done
for a scalar field theory by imposing additional renormalization conditions for
some of the nonrenormalizable couplings. It turns out that one so obtains a
statement on the predictivity of the effective theory at scales far below the
UV cutoff. In particular, nonrenormalizable theories can be treated without
problems in the proposed framework. In the second part, the standard covariant
BRS quantization program for Euclidean Einstein gravity is applied. A momentum
cutoff regularization is imposed and the resulting violation of the
Slavnov-Taylor identities is discussed. Deriving Polchinski's renormalization
group equation for Euclidean quantum gravity, the predictivity of effective
quantum gravity at scales far below the Planck scale is investigated with flow
equations. A fine-tuning procedure for restoring the violated Slavnov-Taylor
identities is proposed and it is argued that in the effective quantum gravity
context, the restoration will only be accomplished with finite accuracy.
Finally, the no-cutoff limit of Euclidean quantum gravity is analyzed from the
viewpoint of the Polchinski method. It is speculated whether a limit with
nonvanishing gravitational constant might exist where the latter would
ultimatively be determined by the cosmological constant and the masses of the
elementary particles.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 14:49:11 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Neugebohrn",
"Falk",
""
]
] |
0704.3206 | Luca Del Zanna | L. Del Zanna, O. Zanotti, N. Bucciantini, P. Londrillo | ECHO: an Eulerian Conservative High Order scheme for general
relativistic magnetohydrodynamics and magnetodynamics | 20 pages, revised version submitted to A&A | null | 10.1051/0004-6361:20077093 | null | astro-ph gr-qc | null | We present a new numerical code, ECHO, based on an Eulerian Conservative High
Order scheme for time dependent three-dimensional general relativistic
magnetohydrodynamics (GRMHD) and magnetodynamics (GRMD). ECHO is aimed at
providing a shock-capturing conservative method able to work at an arbitrary
level of formal accuracy (for smooth flows), where the other existing GRMHD and
GRMD schemes yield an overall second order at most. Moreover, our goal is to
present a general framework, based on the 3+1 Eulerian formalism, allowing for
different sets of equations, different algorithms, and working in a generic
space-time metric, so that ECHO may be easily coupled to any solver for
Einstein's equations. Various high order reconstruction methods are implemented
and a two-wave approximate Riemann solver is used. The induction equation is
treated by adopting the Upwind Constrained Transport (UCT) procedures,
appropriate to preserve the divergence-free condition of the magnetic field in
shock-capturing methods. The limiting case of magnetodynamics (also known as
force-free degenerate electrodynamics) is implemented by simply replacing the
fluid velocity with the electromagnetic drift velocity and by neglecting the
matter contribution to the stress tensor. ECHO is particularly accurate,
efficient, versatile, and robust. It has been tested against several
astrophysical applications, including a novel test on the propagation of large
amplitude circularly polarized Alfven waves. In particular, we show that
reconstruction based on a Monotonicity Preserving filter applied to a fixed
5-point stencil gives highly accurate results for smooth solutions, both in
flat and curved metric (up to the nominal fifth order), while at the same time
providing sharp profiles in tests involving discontinuities.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 14:51:49 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Del Zanna",
"L.",
""
],
[
"Zanotti",
"O.",
""
],
[
"Bucciantini",
"N.",
""
],
[
"Londrillo",
"P.",
""
]
] |
0704.3207 | Serguei Molodtsov | A.E. Dorokhov, S.V. Molodtsov, G.M. Zinovjev | Gluon condensate behaviour at filling the Fermi sphere up | 16 pages, 7 figures | null | null | null | hep-ph | null | The impact of filling up the Fermi sphere with the quarks, which dynamically
generated their masses on the instanton liquid at finite temperature and
baryonic/quark number density, is investigated. It is demonstrated, in
particular, that the boundary of chiral symmetry restoration phase transition
is shifted to the larger (about 100 MeV more) value of quark chemical potential
compared to the magnitude inherent in the Nambu-Jona-Lasinio model.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 14:55:03 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Dorokhov",
"A. E.",
""
],
[
"Molodtsov",
"S. V.",
""
],
[
"Zinovjev",
"G. M.",
""
]
] |
0704.3208 | Marcelo de Moura Leite | Paulo R. S. Carvalho and Marcelo M. Leite | Callan-Symanzik method for $m$-axial Lifshitz points | REVTeX 4, 22 pages | Annals Phys.324:178-204,2009; Erratum-ibid.324:2452,2009 | 10.1016/j.aop.2008.05.006 10.1016/j.aop.2009.07.008 | null | hep-th | null | We introduce the Callan-Symanzik method in the description of anisotropic as
well as isotropic Lifshitz critical behaviors. Renormalized perturbation
theories are defined by normalization conditions with nonvanishing masses and
at zero external momenta. The orthogonal approximation is employed to obtain
the critical indices $\eta_{L2}$, $\nu_{L2}$, $\eta_{L4}$ and $\nu_{L4}$
diagramatically at least up to two-loop order in the anisotropic criticalities.
This approximation is also utilized to compute the exponents $\eta_{L4}$ and
$\nu_{L4}$ in the isotropic case. Furthermore, we compute those exponents
exactly for the isotropic behaviors at the same loop order. The results
obtained for all exponents are in perfect agreement with those previously
derived in the massless theories renormalized at nonzero external momenta.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 14:57:32 GMT"
}
] | 2009-10-06T00:00:00 | [
[
"Carvalho",
"Paulo R. S.",
""
],
[
"Leite",
"Marcelo M.",
""
]
] |
0704.3209 | Wang-Kong Tse | Wang-Kong Tse, Ben Yu-Kuang Hu, S. Das Sarma | Coulomb Drag in Graphene | null | Phys. Rev. B 76, 081401(R) (2007) | 10.1103/PhysRevB.76.081401 | null | cond-mat.mes-hall | null | We study the Coulomb drag between two single graphene sheets in intrinsic and
extrinsic graphene systems with no interlayer tunneling. The general expression
for the nonlinear susceptibility appropriate for single-layer graphene systems
is derived using the diagrammatic perturbation theory, and the corresponding
exact zero-temperature expression is obtained analytically. We find that,
despite the existence of a non-zero conductivity in an intrinsic graphene
layer, the Coulomb drag between intrinsic graphene layers vanishes at all
temperatures. In extrinsic systems, we obtain numerical results and an
approximate analytical result for the drag resistivity $\rho_{\textrm{D}}$, and
find that $\rho_{\textrm{D}}$ goes as $T^2$ at low temperature $T$, as $1/d^4$
for large bilayer separation $d$ and $1/n^3$ for high carrier density $n$. We
also discuss qualitatively the effect of plasmon-induced enhancement on the
Coulomb drag, which should occur at a temperature of the order of or higher
than the Fermi temperature.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 17:26:10 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Tse",
"Wang-Kong",
""
],
[
"Hu",
"Ben Yu-Kuang",
""
],
[
"Sarma",
"S. Das",
""
]
] |
0704.3210 | Ganpathy Murthy | Ganpathy Murthy, R. Shankar | Hamiltonian theory of the half-filled Landau level with disorder:
Application to recent NMR data | 21 pages, 6 figures | null | 10.1103/PhysRevB.76.075341 | null | cond-mat.mes-hall | null | The Hamiltonian Theory of the fractional quantum Hall effect is an operator
description that subsumes many properties of Composite Fermions, applies to
gapped and gapless cases, and has been found to provide results in quantitative
accord with data on gaps, relaxation rates and polarizations at temperatures of
$300mK$ and above. The only free parameter is $\lambda$, which is related to
the sample thickness and appears in the Zhang-Das Sarma potential $v(q) = {2\pi
e^2\over \kappa q} e^{-ql\lambda}$ where $l$ and $\kappa $ are the magnetic
length and dielectric constant. Here we examine the recent data of Tracy and
Eisenstein on the nuclear magnetic resonance relaxation rate at filling factor
$\nu=\half$ deduced from resistivity measurements at temperatures as low as
$45mK$. We find that their results can be satisfactorily described by this
theory, if in addition to a $v(q)$ with $\lambda \simeq 2$, a constant disorder
width $\Gamma\simeq 100 mK$ is incorporated.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 15:02:50 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Murthy",
"Ganpathy",
""
],
[
"Shankar",
"R.",
""
]
] |
0704.3211 | Fabio Peano | F. Peano, G. Coppa, F. Peinetti, R. Mulas, and L. O. Silva | Ergodic model for the expansion of spherical nanoplasmas | To appear on Physical Review E | null | 10.1103/PhysRevE.75.066403 | null | physics.plasm-ph | null | Recently, the collisionless expansion of spherical nanoplasmas has been
analyzed with a new ergodic model, clarifying the transition from
hydrodynamic-like to Coulomb-explosion regimes, and providing accurate laws for
the relevant features of the phenomenon. A complete derivation of the model is
here presented. The important issue of the self-consistent initial conditions
is addressed by analyzing the initial charging transient due to the electron
expansion, in the approximation of immobile ions. A comparison among different
kinetic models for the expansion is presented, showing that the ergodic model
provides a simplified description, which retains the essential information on
the electron distribution, in particular, the energy spectrum. Results are
presented for a wide range of initial conditions (determined from a single
dimensionless parameter), in excellent agreement with calculations from the
exact Vlasov-Poisson theory, thus providing a complete and detailed
characterization of all the stages of the expansion.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 15:26:00 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Peano",
"F.",
""
],
[
"Coppa",
"G.",
""
],
[
"Peinetti",
"F.",
""
],
[
"Mulas",
"R.",
""
],
[
"Silva",
"L. O.",
""
]
] |
0704.3212 | Ryan Heary | R. J. Heary, J. E. Han and Lingyin Zhu | Spin-charge filtering through a spin-orbit coupled quantum dot
controlled via an Aharonov-Bohm interferometer | 8 pages, 10 figures | null | 10.1103/PhysRevB.77.115132 | null | cond-mat.str-el cond-mat.mes-hall | null | We show that a strongly correlated quantum dot embedded in an Aharonov-Bohm
interferometer can be used to filter both charge and spin at zero voltage bias.
The magnitude with which the Aharonov-Bohm arm is coupled to the system
controls the many-body effects on the quantum dot. When the quantum dot is in
the Kondo regime the flow of charge through the system can be tuned by the
phase of the Aharonov-Bohm arm, $\phi_{AB}$. Furthermore when a spin-orbit
interaction is present on a Kondo quantum dot we can control the flow of spin
by the spin-orbit phase, $\phi_{SO}$. The existence of the Kondo peak at the
Fermi energy makes it possible to control the flow of both charge and spin in
the zero voltage bias limit.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 15:25:34 GMT"
},
{
"version": "v2",
"created": "Wed, 11 Jul 2007 15:58:39 GMT"
},
{
"version": "v3",
"created": "Tue, 20 Nov 2007 16:19:52 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Heary",
"R. J.",
""
],
[
"Han",
"J. E.",
""
],
[
"Zhu",
"Lingyin",
""
]
] |
0704.3213 | Lasse Rempe | G\"unter Rottenfu{\ss}er, Johannes R\"uckert, Lasse Rempe and Dierk
Schleicher | Dynamic rays of bounded-type entire functions | 42 pages, 9 figures. V2. General revisions and corrections.
Definition of the class \B_{\log} harmonized with other papers; some results
added/restated for future reference; details added in proofs of Theorem 6.3
and of Lemma A.3 | Ann. of Math. 173 (2011), no. 1, 77-125 | 10.4007/annals.2010.173.1.3 | Stony Brook IMS Preprint #2007/05 | math.DS math.CV math.GN | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We construct an entire function in the Eremenko-Lyubich class $\B$ whose
Julia set has only bounded path-components. This answers a question of Eremenko
from 1989 in the negative.
On the other hand, we show that for many functions in $\B$, in particular
those of finite order, every escaping point can be connected to $\infty$ by a
curve of escaping points. This gives a partial positive answer to the
aforementioned question of Eremenko, and answers a question of Fatou from 1926.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 15:19:58 GMT"
},
{
"version": "v2",
"created": "Sat, 28 Feb 2009 22:56:29 GMT"
}
] | 2011-01-07T00:00:00 | [
[
"Rottenfußer",
"Günter",
""
],
[
"Rückert",
"Johannes",
""
],
[
"Rempe",
"Lasse",
""
],
[
"Schleicher",
"Dierk",
""
]
] |
0704.3214 | Dario Benedetti | D. Benedetti, R. Loll, F. Zamponi | (2+1)-Dimensional Quantum Gravity as the Continuum Limit of Causal
Dynamical Triangulations | 38 pages, 13 figures | Phys.Rev.D76:104022,2007 | 10.1103/PhysRevD.76.104022 | null | hep-th gr-qc | null | We perform a non-perturbative sum over geometries in a (2+1)-dimensional
quantum gravity model given in terms of Causal Dynamical Triangulations.
Inspired by the concept of triangulations of product type introduced
previously, we impose an additional notion of order on the discrete, causal
geometries. This simplifies the combinatorial problem of counting geometries
just enough to enable us to calculate the transfer matrix between boundary
states labelled by the area of the spatial universe, as well as the
corresponding quantum Hamiltonian of the continuum theory. This is the first
time in dimension larger than two that a Hamiltonian has been derived from such
a model by mainly analytical means, and opens the way for a better
understanding of scaling and renormalization issues.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 15:22:13 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Benedetti",
"D.",
""
],
[
"Loll",
"R.",
""
],
[
"Zamponi",
"F.",
""
]
] |
0704.3215 | Oleg Ruchayskiy | Oleg Ruchayskiy | Restrictions on sterile neutrino parameters from astrophysical
observations | 3 pages. Contribution to the Proceedings of 11 Marcel Grossmann
meeting | null | 10.1142/9789812834300_0052 | null | astro-ph | null | Adding 3 right-handed (sterile) neutrino to the Standard Model (SM) can solve
several "beyond the Standard Model" problems within one consistent framework:
explain neutrino oscillations and baryon asymmetry of the Universe and provide
a dark matter (DM) candidate. In this talk I will present current status of
astrophysical searches for the DM sterile neutrino.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 15:32:41 GMT"
}
] | 2016-11-15T00:00:00 | [
[
"Ruchayskiy",
"Oleg",
""
]
] |
0704.3216 | Joel Merker | Joel Merker and Egmont Porten | The Hartogs extension theorem on (n-1)-complete complex spaces | 19 pages, 5 figures | null | null | null | math.CV math.DG | null | Employing Morse theory for the global control of monodromy and the method of
analytic discs for local extension, we establish a version of the global
Hartogs extension theorem in a singular setting: for every domain D of an
(n-1)-complete normal complex space X of pure dimension n >= 2 and for every
compact set K in D such that D - K is connected, holomorphic or meromorphic
functions in D - K extend holomorphically or meromorphically to D. Normality is
an unvavoidable assumption for holomorphic extension, but we show that
meromorphic extension holds on a reduced globally irreducible (not necessarily
normal) X of pure dimension n >=2 provided that the regular part of D - K is
connected.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 15:22:33 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Merker",
"Joel",
""
],
[
"Porten",
"Egmont",
""
]
] |
0704.3217 | Dmitry Novikov | Dmitry Novikov | On limit cycles appearing by polynomial perturbation of Darbouxian
integrable systems | 21 pages, 2 figures, LaTeX | null | null | null | math.CA math.DS | null | We prove an existential finiteness Varchenko-Khovanskii type result for
integrals of rational 1-forms over the level curves of Darbouxian integrals.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 16:04:25 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Novikov",
"Dmitry",
""
]
] |
0704.3218 | Cornelius Krellner | C. Krellner, S. Haas, C. Goldmann, K. P. Pernstich, D. J. Gundlach, B.
Batlogg (Laboratory for Solid State Physics, ETH Zurich, Switzerland) | Density of bulk trap states in organic semiconductor crystals: discrete
levels induced by oxygen in rubrene | published in Phys. Rev. B, high quality figures:
http://www.cpfs.mpg.de/~krellner/ | Phys. Rev. B 75, 245115 (2007) | 10.1103/PhysRevB.75.245115 | null | cond-mat.mtrl-sci | null | The density of trap states in the bandgap of semiconducting organic single
crystals has been measured quantitatively and with high energy resolution by
means of the experimental method of temperature-dependent
space-charge-limited-current spectroscopy (TD-SCLC). This spectroscopy has been
applied to study bulk rubrene single crystals, which are shown by this
technique to be of high chemical and structural quality. A density of deep trap
states as low as ~ 10^{15} cm^{-3} is measured in the purest crystals, and the
exponentially varying shallow trap density near the band edge could be
identified (1 decade in the density of states per ~25 meV). Furthermore, we
have induced and spectroscopically identified an oxygen related sharp hole bulk
trap state at 0.27 eV above the valence band.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 15:39:37 GMT"
},
{
"version": "v2",
"created": "Tue, 19 Jun 2007 10:47:39 GMT"
}
] | 2007-06-19T00:00:00 | [
[
"Krellner",
"C.",
"",
"Laboratory for Solid State Physics, ETH Zurich, Switzerland"
],
[
"Haas",
"S.",
"",
"Laboratory for Solid State Physics, ETH Zurich, Switzerland"
],
[
"Goldmann",
"C.",
"",
"Laboratory for Solid State Physics, ETH Zurich, Switzerland"
],
[
"Pernstich",
"K. P.",
"",
"Laboratory for Solid State Physics, ETH Zurich, Switzerland"
],
[
"Gundlach",
"D. J.",
"",
"Laboratory for Solid State Physics, ETH Zurich, Switzerland"
],
[
"Batlogg",
"B.",
"",
"Laboratory for Solid State Physics, ETH Zurich, Switzerland"
]
] |
0704.3219 | Juan Manuel Borrero | J.M. Borrero | The structure of sunspot penumbrae IV. MHS equilibrium for penumbral
flux tubes and the origin of dark core penumbral filaments and penumbral
grains | Accepted for publication in Astronomy & Astrophysics. 10 pages, 7
figures (3 color figures) | null | 10.1051/0004-6361:20066776 | null | astro-ph | null | We study the magnetohydrostatic equilibrium of magnetic flux tubes with
circular cross sections embedded in a magnetic surrounding atmosphere. We solve
the static momentum equation in 2.5D to obtain the thermodynamics that are
consistent with a prescribed velocity and magnetic fields. We show that force
balance is roughly satisfied if the flux tube's magnetic field is aligned with
its axis. Equilibrium is guaranteed if this magnetic field possesses a
transverse component. Several forms of this transverse field are investigated.
The resulting magnetic field configurations are critically reviewed in terms of
the results from spectropolarimetric observations. The thermodynamic structure
that allows the flux tube to be in mechanical equilibrium is also calculated.
We show that the inferred pressure, density and temperature stratification
reproduce intensity features similar to dark core penumbral filaments and
penumbral grains.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 15:42:28 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Borrero",
"J. M.",
""
]
] |
0704.3220 | Peter Horvathy | P. A. Horvathy | Lectures on (abelian) Chern-Simons vortices | 51 pages, 9 figures. Lectures delivered at NIKHEF (Amsterdam), July
2006 | null | null | null | hep-th | null | Various aspects including the construction and the symmetries of Abelian
Chern-Simons vortices are reviewed. Extended version of the Lectures delivered
at NIKHEF (Amsterdam), July 2006. Typos corrected, some refernces added.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 15:43:22 GMT"
},
{
"version": "v2",
"created": "Wed, 9 May 2007 13:41:18 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Horvathy",
"P. A.",
""
]
] |
0704.3221 | Manuel Lladser | Manuel Lladser, M. D. Betterton, Rob Knight | Multiple pattern matching: A Markov chain approach | Final version to appear in the Journal of Mathematical Biology | null | null | null | math.PR math.CO math.ST q-bio.GN q-bio.QM stat.TH | null | RNA motifs typically consist of short, modular patterns that include base
pairs formed within and between modules. Estimating the abundance of these
patterns is of fundamental importance for assessing the statistical
significance of matches in genomewide searches, and for predicting whether a
given function has evolved many times in different species or arose from a
single common ancestor. In this manuscript, we review in an integrated and
self-contained manner some basic concepts of automata theory, generating
functions and transfer matrix methods that are relevant to pattern analysis in
biological sequences. We formalize, in a general framework, the concept of
Markov chain embedding to analyze patterns in random strings produced by a
memoryless source. This conceptualization, together with the capability of
automata to recognize complicated patterns, allows a systematic analysis of
problems related to the occurrence and frequency of patterns in random strings.
The applications we present focus on the concept of synchronization of
automata, as well as automata used to search for a finite number of keywords
(including sets of patterns generated according to base pairing rules) in a
general text.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 17:12:45 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Lladser",
"Manuel",
""
],
[
"Betterton",
"M. D.",
""
],
[
"Knight",
"Rob",
""
]
] |
0704.3222 | Yves van Gennip | Yves van Gennip and Mark A. Peletier | Copolymer-homopolymer blends: global energy minimisation and global
energy bounds | 31 pages, 6 Postscript figures; to be published in Calc. Var. Partial
Differential Equations. Version history: Changes in v2 w.r.t v1 only concern
metadata. V3 contains some minor revisions and additions w.r.t. v2. V4
corrects a confusing typo in one of the formulas of the appendix. V5 is the
definitive version that will appear in print | null | null | null | math-ph math.MP | null | We study a variational model for a diblock-copolymer/homopolymer blend. The
energy functional is a sharp-interface limit of a generalisation of the
Ohta-Kawasaki energy. In one dimension, on the real line and on the torus, we
prove existence of minimisers of this functional and we describe in complete
detail the structure and energy of stationary points. Furthermore we
characterise the conditions under which the minimisers may be non-unique.
In higher dimensions we construct lower and upper bounds on the energy of
minimisers, and explicitly compute the energy of spherically symmetric
configurations.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 16:07:46 GMT"
},
{
"version": "v2",
"created": "Wed, 25 Apr 2007 11:17:41 GMT"
},
{
"version": "v3",
"created": "Mon, 17 Sep 2007 09:45:28 GMT"
},
{
"version": "v4",
"created": "Tue, 18 Sep 2007 10:21:56 GMT"
},
{
"version": "v5",
"created": "Tue, 30 Oct 2007 09:21:36 GMT"
}
] | 2007-10-30T00:00:00 | [
[
"van Gennip",
"Yves",
""
],
[
"Peletier",
"Mark A.",
""
]
] |
0704.3223 | Benedikt Obermayer | Benedikt Obermayer and Oskar Hallatschek | Coupling of transverse and longitudinal response in stiff polymers | 4 pages, 3 figures, 1 table; final version | Phys. Rev. Lett. 99 (2007) 098302 | 10.1103/PhysRevLett.99.098302 | LMU-ASC 25/07 | cond-mat.soft q-bio.BM | null | The time-dependent transverse response of stiff polymers, represented as
weakly-bending wormlike chains (WLCs), is well-understood on the linear level,
where transverse degrees of freedom evolve independently from the longitudinal
ones. We show that, beyond a characteristic time scale, the nonlinear coupling
of transverse and longitudinal motion in an inextensible WLC significantly
weakens the polymer response compared to the widely used linear response
predictions. The corresponding feedback mechanism is rationalized by scaling
arguments and quantified by a multiple scale approach that exploits an inherent
separation of transverse and longitudinal correlation length scales. Crossover
scaling laws and exact analytical and numerical solutions for characteristic
response quantities are derived for different experimentally relevant setups.
Our findings are applicable to cytoskeletal filaments as well as DNA under
tension.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 15:57:03 GMT"
},
{
"version": "v2",
"created": "Mon, 3 Sep 2007 15:19:50 GMT"
}
] | 2007-09-03T00:00:00 | [
[
"Obermayer",
"Benedikt",
""
],
[
"Hallatschek",
"Oskar",
""
]
] |
0704.3224 | Ignacio Negueruela | Ignacio Negueruela (Universidad de Alicante), David M. Smith (UCSC),
Jose Miguel Torrejon (alicante), Pablo Reig (FORTH/University of Crete) | Supergiant Fast X-ray Transients: A common behaviour or a class of
objects? | To appear in ''Proceedings of the 6th Integral Workshop "The obscured
Universe", Moscow, July 3-7 2006'' (replaced with refereed version 10 May
07). Best viewed in PDF format | ESA SP-622, 255 (2008) | null | null | astro-ph | null | INTEGRAL monitoring of the Galactic Plane is revealing a growing number of
recurrent X-ray transients, characterised by short outbursts with very fast
rise times (~ tens of minutes) and typical durations of a few hours. A
substantial fraction of these sources are associated with OB supergiants and
hence define a new class of massive X-ray binaries, which we call Supergiant
Fast X-ray Transients. Characterisation of the astrophysical parameters of
their counterparts is underway. So far, we have found a number of late O and
early B supergiants of different luminosities at a large range of distances.
Nothing in their optical properties sets them apart from classical Supergiant
X-ray Binaries. On the other hand, there is now rather concluding evidence that
persistent supergiant X-ray binaries also show fast outbursts. This suggests a
continuum of behaviours between typical persistent supergiant systems and
purely transient systems, but offers very little information about the physical
causes of the outbursts.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 16:02:33 GMT"
},
{
"version": "v2",
"created": "Thu, 10 May 2007 15:28:38 GMT"
}
] | 2008-01-28T00:00:00 | [
[
"Negueruela",
"Ignacio",
"",
"Universidad de Alicante"
],
[
"Smith",
"David M.",
"",
"UCSC"
],
[
"Torrejon",
"Jose Miguel",
"",
"alicante"
],
[
"Reig",
"Pablo",
"",
"FORTH/University of Crete"
]
] |
0704.3225 | Alexey A. Kryukov | Alexey A. Kryukov | Linear algebra and differential geometry on abstract Hilbert space | 37 pages, 3 figures, see
http://www.uwc.edu/dept/math/faculty/kryukov/ for additional applications | Int. J. Math & Math. Sci. 14, 2241 (2005) | null | null | math-ph math.MP quant-ph | null | Isomorphisms of separable Hilbert spaces are analogous to isomorphisms of
n-dimensional vector spaces. However, while n-dimensional spaces in
applications are always realized as the Euclidean space R^n, Hilbert spaces
admit various useful realizations as spaces of functions. In the paper this
simple observation is used to construct a fruitful formalism of local
coordinates on Hilbert manifolds. Images of charts on manifolds in the
formalism are allowed to belong to arbitrary Hilbert spaces of functions
including spaces of generalized functions. Tensor equations then describe
families of functional equations on various spaces of functions. The formalism
itself and its applications in linear algebra, differential equations and
differential geometry are analyzed.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 16:03:01 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Kryukov",
"Alexey A.",
""
]
] |
0704.3226 | Radhakrishnan Nagarajan | Radhakrishnan Nagarajan | Delay estimation in a two-node acyclic network | 33 Pages, 6 Figures | Physica A: Volume 376, 15 March 2007, Pages 725-737 | 10.1016/j.physa.2006.10.067 | null | q-bio.QM q-bio.MN | null | Linear measures such as cross-correlation have been used successfully to
determine time delays from the given processes. Such an analysis often precedes
identifying possible causal relationships between the observed processes. The
present study investigates the impact of a positively correlated driver whose
correlation function decreases monotonically with lag on the delay estimation
in a two-node acyclic network with one and two-delays. It is shown that
cross-correlation analysis of the given processes can result in spurious
identification of multiple delays between the driver and the dependent
processes. Subsequently, delay estimation of increment process as opposed to
the original process under certain implicit constraints is explored.
Short-range and long-range correlated driver processes along with those of
their coarse-grained counterparts are considered.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 16:07:15 GMT"
}
] | 2015-05-13T00:00:00 | [
[
"Nagarajan",
"Radhakrishnan",
""
]
] |
0704.3227 | O. Stenull | Olaf Stenull | Smectic elastomer membranes | 10 pages, 2 figures | Phys. Rev. E 75, 051702 (2007) | 10.1103/PhysRevE.75.051702 | null | cond-mat.soft | null | We present a model for smectic elastomer membranes which includes elastic and
liquid crystalline degrees of freedom. Based on our model, we determined the
qualitative phase diagram of a smectic elastomer membrane using mean-field
theory. This phase diagram is found to comprise five phases, viz.
smectic-A--flat, smectic-A--crumpled, smectic-C--flat, smectic-C--crumpled and
smectic-C--tubule, where in the latter phase, the membrane is flat in the
direction of mesogenic tilt and crumpled in the perpendicular direction. The
transitions between adjacent phases are second order phase transitions. We
study in some detail the elasticity of the smectic-C--flat and the
smectic-C--tubule phases which are associated with a spontaneous breaking of
in-plane rotational symmetry. As a consequence of the Goldstone theorem, these
phases exhibit soft elasticity characterized by the vanishing of in-plane shear
moduli.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 16:08:37 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Stenull",
"Olaf",
""
]
] |
0704.3228 | Thomas Silverston | Thomas Silverston, Olivier Fourmaux and Kave Salamatian | Characterization of P2P IPTV Traffic: Scaling Analysis | 27p, submitted to a conference | null | null | null | cs.NI cs.MM | null | P2P IPTV applications arise on the Internet and will be massively used in the
future. It is expected that P2P IPTV will contribute to increase the overall
Internet traffic. In this context, it is important to measure the impact of P2P
IPTV on the networks and to characterize this traffic. Dur- ing the 2006 FIFA
World Cup, we performed an extensive measurement campaign. We measured network
traffic generated by broadcasting soc- cer games by the most popular P2P IPTV
applications, namely PPLive, PPStream, SOPCast and TVAnts. From the collected
data, we charac- terized the P2P IPTV traffic structure at different time
scales by using wavelet based transform method. To the best of our knowledge,
this is the first work, which presents a complete multiscale analysis of the
P2P IPTV traffic. Our results show that the scaling properties of the TCP
traffic present periodic behavior whereas the UDP traffic is stationary and
lead to long- range depedency characteristics. For all the applications, the
download traffic has different characteristics than the upload traffic. The
signaling traffic has a significant impact on the download traffic but it has
negligible impact on the upload. Both sides of the traffic and its granularity
has to be taken into account to design accurate P2P IPTV traffic models.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 16:18:13 GMT"
},
{
"version": "v2",
"created": "Tue, 17 Jul 2007 14:26:05 GMT"
}
] | 2007-07-17T00:00:00 | [
[
"Silverston",
"Thomas",
""
],
[
"Fourmaux",
"Olivier",
""
],
[
"Salamatian",
"Kave",
""
]
] |
0704.3229 | Tabetha Boyajian | T. S. Boyajian, D. R. Gies, J. P. Dunn, C. D. Farrington, E. D.
Grundstrom, W. Huang, M. V. McSwain, S. J. Williams, D. W. Wingert, A. W.
Fullerton, C. T. Bolton | The Long Period, Massive Binaries HD 37366 and HD 54662: Potential
Targets for Long Baseline Optical Interferometry | 27 pages, 8 figures, Accepted for publication in ApJ | Astrophys.J.664:1121-1129,2007 | 10.1086/519015 | null | astro-ph | null | We present the results from an optical spectroscopic analysis of the massive
stars HD 37366 and HD 54662. We find that HD 37366 is a double-lined
spectroscopic binary with a period of 31.8187 +/- 0.0004 days, and HD 54662 is
also a double lined binary with a much longer period of 557.8 +/- 0.3 days. The
primary of HD 37366 is classified as O9.5 V, and it contributes approximately
two-thirds of the optical flux. The less luminous secondary is a broad-lined,
early B-type main-sequence star. Tomographic reconstruction of the individual
spectra of HD 37366 reveals absorption lines present in each component,
enabling us to constrain the nature of the secondary and physical
characteristics of both stars. Tomographic reconstruction was not possible for
HD 54662; however, we do present mean spectra from our observations that show
that the secondary component is approximately half as bright as the primary.
The observed spectral energy distributions (SEDs) were fit with model SEDs and
galactic reddening curves to determine the angular sizes of the stars. By
assuming radii appropriate for their classifications, we determine distance
ranges of 1.4 - 1.9 and 1.2 - 1.5 kpc for HD 37366 and HD 54662, respectively.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 16:11:15 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Boyajian",
"T. S.",
""
],
[
"Gies",
"D. R.",
""
],
[
"Dunn",
"J. P.",
""
],
[
"Farrington",
"C. D.",
""
],
[
"Grundstrom",
"E. D.",
""
],
[
"Huang",
"W.",
""
],
[
"McSwain",
"M. V.",
""
],
[
"Williams",
"S. J.",
""
],
[
"Wingert",
"D. W.",
""
],
[
"Fullerton",
"A. W.",
""
],
[
"Bolton",
"C. T.",
""
]
] |
0704.3230 | Axel Arnold | Axel Arnold and Suckjoon Jun | Time scale of entropic segregation of flexible polymers in confinement:
Implications for chromosome segregation in filamentous bacteria | Minor changes. Added some references, corrected the labels in figure
6 and reformatted in two columns. Also added reference to published version
in PRE | A. Arnold and S. Jun, Phys. Rev. E 76, 031901 (2007) | 10.1103/PhysRevE.76.031901 | null | cond-mat.soft | null | We report molecular dynamics simulations of the segregation of two
overlapping chains in cylindrical confinement. We find that the entropic
repulsion between the chains can be sufficiently strong to cause segregation on
a time scale that is short compared to the one for diffusion. This result
implies that entropic driving forces are sufficiently strong to cause rapid
bacterial chromosome segregation.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 16:14:25 GMT"
},
{
"version": "v2",
"created": "Fri, 7 Sep 2007 14:02:09 GMT"
}
] | 2011-11-09T00:00:00 | [
[
"Arnold",
"Axel",
""
],
[
"Jun",
"Suckjoon",
""
]
] |
0704.3231 | Ravi Vakil | Robert W. Easton and Ravi Vakil | Absolute Galois acts faithfully on the components of the moduli space of
surfaces: A Belyi-type theorem in higher dimension | 7 pages | null | null | null | math.AG math.NT | null | Given an object over the algebraic closure Qbar of Q, there is often no
reason for invariants of the corresponding holomorphic object to be preserved
by the absolute Galois group Gal(Qbar/Q), and in general this is not true,
although it is sometimes surprising to observe in practice. The case of covers
of the projective line branched only over the points 0, 1, and infinity,
through Belyi's theorem, leads to Grothendieck's dessins d'enfants program for
understanding the absolute Galois group through its faithful action on such
covers. This note is motivated by Catanese's question about a
higher-dimensional analogue: does the absolute Galois group act faithfully on
the deformation equivalence classes of smooth surfaces? (These equivalence
classes are of course by definition the strongest deformation invariants.) We
give a short proof of a weaker result: the absolute Galois group acts
faithfully on the irreducible components of the moduli space of smooth surfaces
(of general type, canonically polarized). Bauer, Catanese, and Grunewald have
recently answered Catanese's original question using a different construction.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 16:22:27 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Easton",
"Robert W.",
""
],
[
"Vakil",
"Ravi",
""
]
] |
0704.3232 | S\'andor Szab\'o | V.E.S. Szabo | Characterization of polynomials | 5 pages | Analysis and Applications (Vol. 11, No. 02, March 2013) | 10.1142/S0219530513500152 | null | math.AP math.FA | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | In 1954 it was proved if f is infinitely differentiable in the interval I and
some derivative (of order depending on x) vanishes at each x, then f is a
polynomial. Later it was generalized for multi-variable case. In this paper we
give an extension for distributions.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 16:22:40 GMT"
},
{
"version": "v2",
"created": "Tue, 22 Jul 2014 17:28:14 GMT"
}
] | 2014-07-23T00:00:00 | [
[
"Szabo",
"V. E. S.",
""
]
] |
0704.3233 | Marcelo Alloy | M. D. Alloy and D. P. Menezes | Slowly rotating pulsars | null | Int.J.Mod.Phys.E16:2826-2829,2007 | 10.1142/S0218301307008501 | null | astro-ph nucl-th | null | In the present work we investigate one possible variation on the usual static
pulsars: the inclusion of rotation. We use a formalism proposed by Hartle and
Thorne to calculate the properties of rotating pulsars with all possible
compositions. All calculations were performed for zero temperature and also for
fixed entropy equations of state.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 16:30:12 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"Alloy",
"M. D.",
""
],
[
"Menezes",
"D. P.",
""
]
] |
0704.3234 | Bernd-Jochen Schaefer | Bernd-Jochen Schaefer, Jan M. Pawlowski, Jochen Wambach | The Phase Structure of the Polyakov--Quark-Meson Model | 13 pages, 12 figures, RevTex4; discussion of mu-dependence extended,
references added, version to be published in PRD | Phys.Rev.D76:074023,2007 | 10.1103/PhysRevD.76.074023 | null | hep-ph hep-lat hep-th nucl-th | null | The relation between the deconfinement and chiral phase transition is
explored in the framework of an Polyakov-loop-extended two-flavor quark-meson
(PQM) model. In this model the Polyakov loop dynamics is represented by a
background temporal gauge field which also couples to the quarks. As a novelty
an explicit quark chemical potential and N_f-dependence in the Polyakov loop
potential is proposed by using renormalization group arguments. The behavior of
the Polyakov loop as well as the chiral condensate as function of temperature
and quark chemical potential is obtained by minimizing the grand canonical
thermodynamic potential of the system. The effect of the Polyakov loop dynamics
on the chiral phase diagram and on several thermodynamic bulk quantities is
presented.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 18:59:18 GMT"
},
{
"version": "v2",
"created": "Mon, 24 Sep 2007 15:54:40 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Schaefer",
"Bernd-Jochen",
""
],
[
"Pawlowski",
"Jan M.",
""
],
[
"Wambach",
"Jochen",
""
]
] |
0704.3235 | Stephen Skinner | S.L. Skinner, S.A. Zhekov, M. Guedel, W. Schmutz | XMM-Newton X-ray Observations of the Wolf-Rayet Binary System WR 147 | 8 pages, 7 figures | Mon.Not.Roy.Astron.Soc.378:1491-1498,2007 | 10.1111/j.1365-2966.2007.11892.x | null | astro-ph | null | We present results of a 20 ksec X-ray observation of the Wolf-Rayet (WR)
binary system WR 147 obtained with XMM-Newton. Previous studies have shown that
this system consists of a nitrogen-type WN8 star plus an OB companion whose
winds are interacting to produce a colliding wind shock. X-ray spectra from the
pn and MOS detectors confirm the high extinction reported from IR studies and
reveal hot plasma including the first detection of the Fe K-alpha line complex
at 6.67 keV. Spectral fits with a constant-temperature plane-parallel shock
model give a shock temperature kT(shock) = 2.7 keV [T(shock) ~ 31 MK], close to
but slightly hotter than the maximum temperature predicted for a colliding wind
shock. Optically thin plasma models suggest even higher temperatures, which are
not yet ruled out. The X-ray spectra are harder than can be accounted for using
2D numerical colliding wind shock models based on nominal mass-loss parameters.
Possible explanations include: (i) underestimates of the terminal wind speeds
or wind abundances, (ii) overly simplistic colliding wind models, or (iii) the
presence of other X-ray emission mechanisms besides colliding wind shocks.
Further improvement of the numerical models to include potentially important
physics such as non-equilibrium ionization will be needed to rigorously test
the colliding wind interpretation.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 16:33:41 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"Skinner",
"S. L.",
""
],
[
"Zhekov",
"S. A.",
""
],
[
"Guedel",
"M.",
""
],
[
"Schmutz",
"W.",
""
]
] |
0704.3236 | Joao Yun | Joao L. Yun, Jose M. Torrelles, Nuno C. Santos | A "diamond-ring" star: the unusual morphologic structure of a young
(multiple?) object | 7 pages, 6 figures | null | 10.1051/0004-6361:20077248 | null | astro-ph | null | We have observed IRAS06468-0325 obtaining optical and infrared images through
IJHKs and L' filters, K-band low-resolution spectroscopy, together with
millimetre line observations of CO and CS. IRAS06468-0325 has a very unusual
and enigmatic morphology with two components: a bright, close to point-like
source (the diamond) and a sharp-edge ring-like structure (the ring). The
source is not detected in the optical, at wavelengths shorter than the I-band.
The diamond is seen in all the imaging bands observed. The ring-like structure
in IRAS06468-0325 is clearly seen in the I, J, H, and Ks. It is not detected in
the L'-band image. Infrared colours of the diamond are compatible with excess
circumstellar emission and a young stellar nature. A strongly non-gaussian and
moderately bright CO(1-0) and {13}CO(2-1) lines are seen towards
IRAS06468-0325, at v_{LSR} of 30.5 km s{-1} (corresponding to a kinematic
distance of 3 kpc). Very weak C{18}O(2-1) and CS(2-1) lines were detected.
K-band spectra of the diamond and of the ring are similar both in the slope of
the continuum and in the presence of lines supporting the idea that the ring is
reflected light from the diamond. With the current data, a few different
scenarios are possible to explain the morphology of this object. However, the
available data seem to favour that the morphology of IRAS06468-0325 correspond
to a young stellar multiple system in a transient stage where a binary
co-exists with a circumbinary disc, similar to the case of GG Tau. In this
case, the sharpness of the well-defined ring may be due to tidal truncation
from dynamic interactions between components in a binary or multiple stellar
system. IRAS06468-0325 may be an important rare case that illustrates a
short-lived stage of the process of binary or multiple star formation.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 16:34:30 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Yun",
"Joao L.",
""
],
[
"Torrelles",
"Jose M.",
""
],
[
"Santos",
"Nuno C.",
""
]
] |
0704.3237 | Jozsef Lorinczi | Massimiliano Gubinelli and Jozsef Lorinczi | Gibbs measures on Brownian currents | 51 pages | null | null | null | math-ph math.FA math.MP math.PR | null | Motivated by applications to quantum field theory we consider Gibbs measures
for which the reference measure is Wiener measure and the interaction is given
by a double stochastic integral and a pinning external potential. In order
properly to characterize these measures through DLR equations, we are led to
lift Wiener measure and other objects to a space of configurations where the
basic observables are not only the position of the particle at all times but
also the work done by test vector fields. We prove existence and basic
properties of such Gibbs measures in the small coupling regime by means of
cluster expansion.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 16:35:08 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Gubinelli",
"Massimiliano",
""
],
[
"Lorinczi",
"Jozsef",
""
]
] |
0704.3238 | Nicolas Troquard | Philippe Balbiani, Andreas Herzig and Nicolas Troquard | Alternative axiomatics and complexity of deliberative STIT theories | Submitted to the Journal of Philosophical Logic; 13 pages excluding
annex | null | 10.1007/s10992-007-9078-7 | null | cs.LO | null | We propose two alternatives to Xu's axiomatization of the Chellas STIT. The
first one also provides an alternative axiomatization of the deliberative STIT.
The second one starts from the idea that the historic necessity operator can be
defined as an abbreviation of operators of agency, and can thus be eliminated
from the logic of the Chellas STIT. The second axiomatization also allows us to
establish that the problem of deciding the satisfiability of a STIT formula
without temporal operators is NP-complete in the single-agent case, and is
NEXPTIME-complete in the multiagent case, both for the deliberative and the
Chellas' STIT.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 16:36:13 GMT"
}
] | 2011-04-29T00:00:00 | [
[
"Balbiani",
"Philippe",
""
],
[
"Herzig",
"Andreas",
""
],
[
"Troquard",
"Nicolas",
""
]
] |
0704.3239 | Klaus Bartschat | X. Guan, O. Zatsarinny, K. Bartschat, B.I. Schneider, J. Feist, C.J.
Noble | A general approach to few-cycle intense laser interactions with complex
atoms | 7 pages (in the Phys. Rev. double column format) with 5 figures;
processed with REVTEX | Physical Review A 76 (2007), 053411 | 10.1103/PhysRevA.76.053411 | null | physics.atom-ph physics.comp-ph | null | A general {\it ab-initio} and non-perturbative method to solve the
time-dependent Schr\"odinger equation (TDSE) for the interaction of a strong
attosecond laser pulse with a general atom, i.e., beyond the models of
quasi-one-electron or quasi-two-electron targets, is described. The field-free
Hamiltonian and the dipole matrices are generated using a flexible $B$-spline
$R$-matrix method. This numerical implementation enables us to construct
term-dependent, non-orthogonal sets of one-electron orbitals for the bound and
continuum electrons. The solution of the TDSE is propagated in time using the
Arnoldi-Lanczos method, which does not require the diagonalization of any large
matrices. The method is illustrated by an application to the multi-photon
excitation and ionization of Ne atoms. Good agreement with $R$-matrix Floquet
calculations for the generalized cross sections for two-photon ionization is
achieved.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 16:39:59 GMT"
},
{
"version": "v2",
"created": "Thu, 13 Sep 2007 19:33:58 GMT"
}
] | 2016-11-17T00:00:00 | [
[
"Guan",
"X.",
""
],
[
"Zatsarinny",
"O.",
""
],
[
"Bartschat",
"K.",
""
],
[
"Schneider",
"B. I.",
""
],
[
"Feist",
"J.",
""
],
[
"Noble",
"C. J.",
""
]
] |
0704.3240 | Avtar Sehra | Avtar S. Sehra | Finite Element Analysis of the Schroedinger Equation | Computational Analysis of Schroedinger Equation | null | null | null | hep-lat | null | The purpose of this work is to test the application of the finite element
method to quantum mechanical problems, in particular for solving the
Schroedinger equation.
We begin with an overview of quantum mechanics, and standard numerical
techniques. We then give an introduction to finite element analysis using the
diffusion equation as an example. Three numerical time evolution methods are
considered: the (tried and tested) Crank-Nicolson method, the continuous
space-time method, and the discontinuous space-time method.
| [
{
"version": "v1",
"created": "Tue, 17 Apr 2007 12:37:35 GMT"
}
] | 2009-09-29T00:00:00 | [
[
"Sehra",
"Avtar S.",
""
]
] |
0704.3241 | Marco Lops | Daniele Angelosante, Ezio Biglieri, Marco Lops | Neighbor Discovery in Wireless Networks:A Multiuser-Detection Approach | null | null | null | null | cs.IT math.IT | null | We examine the problem of determining which nodes are neighbors of a given
one in a wireless network. We consider an unsupervised network operating on a
frequency-flat Gaussian channel, where $K+1$ nodes associate their identities
to nonorthogonal signatures, transmitted at random times, synchronously, and
independently. A number of neighbor-discovery algorithms, based on different
optimization criteria, are introduced and analyzed. Numerical results show how
reduced-complexity algorithms can achieve a satisfactory performance.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 16:46:02 GMT"
}
] | 2007-07-13T00:00:00 | [
[
"Angelosante",
"Daniele",
""
],
[
"Biglieri",
"Ezio",
""
],
[
"Lops",
"Marco",
""
]
] |
0704.3242 | Louise Edwards | L. O. V. Edwards (1), Michael J. Hudson (2), Michael L. Balogh (2),
Russell J. Smith (3) ((1) Universit\'e Laval, (2) University of Waterloo, (3)
Durham University) | Line Emission in the Brightest Cluster Galaxies of the NOAO Fundamental
Plane and Sloan Digital Sky Surveys | Accepted for publication in MNRAS. 13 pages mn2e style with 7 figures
and 2 tables | Mon.Not.Roy.Astron.Soc.379:100-110,2007 | 10.1111/j.1365-2966.2007.11910.x | null | astro-ph | null | We examine the optical emission line properties of Brightest Cluster Galaxies
(BCGs) selected from two large, homogeneous datasets. The first is the X-ray
selected National Optical Astronomy Observatory Fundamental Plane Survey
(NFPS), and the second is the C4 catalogue of optically selected clusters built
from the Sloan Digital Sky Survey Data Release ~3 (SDSS DR3). Our goal is to
better understand the optical line emission in BCGs with respect to properties
of the galaxy and the host cluster. Throughout the analysis we compare the line
emission of the BCGs to that of a control sample made of the other bright
galaxies near the cluster centre. Overall, both the NFPS and SDSS show a modest
fraction of BCGs with emission lines (~15%). No trend in the fraction of
emitting BCGs as a function of galaxy mass or cluster velocity dispersion is
found. However we find that, for those BCGs found in cooling flow clusters,
71^{+9}_{-14}% have optical emission. Furthermore, if we consider only BCGs
within 50kpc of the X-ray centre of a cooling flow cluster, the emission-line
fraction rises further to 100^{+0}_{-15}%. Excluding the cooling flow clusters,
only ~10% of BCGs are line emitting, comparable to the control sample of
galaxies. We show that the physical origin of the emission line activity
varies: in some cases it has LINER-like line ratios, whereas in others it is a
composite of star-formation and LINER-like activity. We conclude that the
presence of emission lines in BCGs is directly related to the cooling of X-ray
gas at the cluster centre.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 16:53:20 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Edwards",
"L. O. V.",
""
],
[
"Hudson",
"Michael J.",
""
],
[
"Balogh",
"Michael L.",
""
],
[
"Smith",
"Russell J.",
""
]
] |
0704.3243 | Konstantinos Andriopoulos | K. Andriopoulos, P. G. L. Leach, A. Maharaj | On Differential Sequences | 29 pages, 2 tables | null | null | null | math-ph math.GR math.MP | null | We introduce the notion of Differential Sequences of ordinary differential
equations. This is motivated by related studies based on evolution partial
differential equations. We discuss the Riccati Sequence in terms of symmetry
analysis, singularity analysis and identification of the complete symmetry
group for each member of the Sequence. The singularity analysis reveals
considerable structure for the values of the coefficients of the leading-order
terms and resonances of the different principal branches. Full proofs of the
symmetry properties are performed for differential equations defined by their
recursion properties and not given in explicit form.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 16:58:54 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Andriopoulos",
"K.",
""
],
[
"Leach",
"P. G. L.",
""
],
[
"Maharaj",
"A.",
""
]
] |
0704.3244 | Marcel Griesemer | M. Griesemer, D. Hasler | On the Smooth Feshbach-Schur Map | 8 pages | null | null | null | math-ph math.FA math.MP | null | A new variant of the Feshbach map, called smooth Feshbach map, has been
introduced recently by Bach et al., in connection with the renormalization
analysis of non-relativistic quantum electrodynamics. We analyze and clarify
its algebraic and analytic properties, and we generalize it to non-selfadjoint
partition operators $\chi$ and $\chib$.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 16:59:04 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Griesemer",
"M.",
""
],
[
"Hasler",
"D.",
""
]
] |
0704.3245 | Marcelo Alloy | M. D. Alloy and D. P. Menezes | Electrically charged pulsars | null | Braz.J.Phys.37:1183-1190,2007 | 10.1590/S0103-97332007000800001 | null | astro-ph | null | n the present work we investigate one possible variation on the usual
electrically neutral pulsars: the inclusion of electric charge. We study the
effect of electric charge in pulsars assuming that the charge distribution is
proportional to the energy density. All calculations were performed for zero
temperature and fixed entropy equations of state.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 17:00:09 GMT"
}
] | 2011-08-04T00:00:00 | [
[
"Alloy",
"M. D.",
""
],
[
"Menezes",
"D. P.",
""
]
] |
0704.3246 | Victor P. Ruban | V. P. Ruban | Nonlinear stage of the Benjamin-Feir instability: Three-dimensional
coherent structures and rogue waves | 11 pages, 7 figures, submitted to PRL | Phys. Rev. Lett. 99, 044502 (2007). | 10.1103/PhysRevLett.99.044502 | null | physics.flu-dyn physics.ao-ph | null | A specific, genuinely three-dimensional mechanism of rogue wave formation, in
a late stage of the modulational instability of a perturbed Stokes deep-water
wave, is recognized through numerical experiments. The simulations are based on
fully nonlinear equations describing weakly three-dimensional potential flows
of an ideal fluid with a free surface in terms of conformal variables.
Spontaneous formation of zigzag patterns for wave amplitude is observed in a
nonlinear stage of the instability. If initial wave steepness is sufficiently
high ($ka>0.06$), these coherent structures produce rogue waves. The most tall
waves appear in ``turns'' of the zigzags. For $ka<0.06$, the structures decay
typically without formation of steep waves.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 17:04:14 GMT"
}
] | 2007-08-01T00:00:00 | [
[
"Ruban",
"V. P.",
""
]
] |
0704.3247 | Caina Hao | C.N. Hao, X.Y. Xia, S. Mao, Z.G. Deng, Hong Wu | The Growth of Black Holes and Their Host Spheroids in (Sub)mm-loud QSOs
at High Redshift | 19 pages,3 figures,submitted to Chin. J. Astron. Astrophys. This
paper was first prepared for publication on August 10th, 2005 | Chin.J.Astron.Astrophys.8:12-24,2008 | 10.1088/1009-9271/8/1/02 | null | astro-ph | null | We study the growth of black holes and stellar population in spheroids at
high redshift using several (sub)mm-loud QSO samples. Applying the same
criteria established in an earlier work, we find that, similar to IR QSOs at
low redshift, the far-infrared emission of these (sub)mm-loud QSOs mainly
originates from dust heated by starbursts. By combining low-z IR QSOs and
high-z (sub)mm-loud QSOs, we find a trend that the star formation rate
($\Mstardot$) increases with the accretion rate ($\Mdot$). We compare the
values of $\Mstardot/\Mdot$ for submm emitting galaxies (SMGs), far-infrared
ultraluminous/hyperluminous QSOs and typical QSOs, and construct a likely
evolution scenario for these objects. The (sub)mm-loud QSO transition phase has
both high $\Mdot$ and $\Mstardot$ and hence is important for establishing the
correlation between the masses of black holes and spheroids.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 17:06:51 GMT"
}
] | 2009-11-16T00:00:00 | [
[
"Hao",
"C. N.",
""
],
[
"Xia",
"X. Y.",
""
],
[
"Mao",
"S.",
""
],
[
"Deng",
"Z. G.",
""
],
[
"Wu",
"Hong",
""
]
] |
0704.3248 | Brendan Guilfoyle | Brendan Guilfoyle and Wilhelm Klingenberg | On C$^2$-smooth Surfaces of Constant Width | 14 pages AMS-LATEX, 5 figures | Tbilisi Math. J. 2 (2009) 1-17 | 10.32513/tbilisi/1528768838 | null | math.DG | null | A number of results for C$^2$-smooth surfaces of constant width in Euclidean
3-space ${\mathbb{E}}^3$ are obtained. In particular, an integral inequality
for constant width surfaces is established. This is used to prove that the
ratio of volume to cubed width of a constant width surface is reduced by
shrinking it along its normal lines. We also give a characterization of
surfaces of constant width that have rational support function.
Our techniques, which are complex differential geometric in nature, allow us
to construct explicit smooth surfaces of constant width in ${\mathbb{E}}^3$,
and their focal sets. They also allow for easy construction of tetrahedrally
symmetric surfaces of constant width.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 17:13:16 GMT"
}
] | 2021-11-15T00:00:00 | [
[
"Guilfoyle",
"Brendan",
""
],
[
"Klingenberg",
"Wilhelm",
""
]
] |
0704.3249 | Andrea Mantile | Ph. Blanchard, R. Figari, A. Mantile | Point Interaction Hamiltonians in Bounded Domains | 18 pages, 3 figures, latex | null | 10.1063/1.2770672 | null | math-ph math.MP math.SP | null | Making use of recent techniques in the theory of selfadjoint extensions of
symmetric operators, we characterize the class of point interaction
Hamiltonians in a 3-D bounded domain with regular boundary. In the particular
case of one point interaction acting in the center of a ball, we obtain an
explicit representation of the point spectrum of the operator togheter with the
corresponding related eigenfunctions. These operators are used to build up a
model-system where the dynamics of a quantum particle depends on the state of a
quantum bit.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 17:16:51 GMT"
},
{
"version": "v2",
"created": "Fri, 27 Apr 2007 16:09:37 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Blanchard",
"Ph.",
""
],
[
"Figari",
"R.",
""
],
[
"Mantile",
"A.",
""
]
] |
0704.3250 | Rui Dilao | Rui Dilao and Rui Alves-Pires | Chaos in the Stormer problem | 19 pages, 5 figures | null | null | null | nlin.CD nlin.SI | null | We survey the few exact results on the Stormer problem describing the
dynamics of charged particles in the Earth magnetosphere. The analysis of this
system leads to the the conclusion that charged particles are trapped in the
Earth magnetosphere or escape to infinity, and the trapping region is bounded
by a torus-like surface, the Van Allen inner radiation belt. In the trapping
region, the motion of the charged particles can be periodic, quasi-period or
chaotic. The three main effects observed in the Earth magnetosphere, radiation
belts, radiation aurorae and South Atlantic anomaly, are described in the
framework described here. We discuss some new mathematical problems suggested
by the analysis of the Stormer problem.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 17:34:43 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Dilao",
"Rui",
""
],
[
"Alves-Pires",
"Rui",
""
]
] |
0704.3251 | Marcos Alexandrino | Marcos M. Alexandrino, Dirk Toeben | Equifocality of a singular riemannian foliation | 10 pages. This version contains some misprints corrections and
improvements of Corollary 1.6 | Proceedings of the American Mathematical Society Proc. Amer. Math.
Soc. (136) (2008), 3271-3280 | null | null | math.DG | null | A singular foliation on a complete riemannian manifold M is said to be
riemannian if each geodesic that is perpendicular at one point to a leaf
remains perpendicular to every leaf it meets. We prove that the regular leaves
are equifocal, i.e., the end point map of a normal foliated vector field has
constant rank. This implies that we can reconstruct the singular foliation by
taking all parallel submanifolds of a regular leaf with trivial holonomy. In
addition, the end point map of a normal foliated vector field on a leaf with
trivial holonomy is a covering map. These results generalize previous results
of the authors on singular riemannian foliations with sections.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 17:38:58 GMT"
},
{
"version": "v2",
"created": "Thu, 24 May 2007 23:13:08 GMT"
}
] | 2011-02-01T00:00:00 | [
[
"Alexandrino",
"Marcos M.",
""
],
[
"Toeben",
"Dirk",
""
]
] |
0704.3252 | Zinovy Malkin | Zinovy Malkin, Natalia Miller | An analysis of celestial pole offset observations in the free core
nutation frequency band | 7 pages, 4 figures; Presented at the EGU 4th General Assembly,
Vienna, Austria, 15-20 April 2007 | In: J. Boehm, A. Pany, H. Schuh (Eds.), Proc. 18th European VLBI
for Geodesy and Astrometry Working Meeting, Vienna, Austria, 12-13 Apr 2007,
Technische Universitaet Wien, 2007, 93-97 | null | null | physics.geo-ph astro-ph.EP | null | In this study, three empirical Free Core Nutation (FCN) models developed to
the present time, MHB2000, Malkin's and Lambert's ones, are compared on the
basis of representation of variations of the FCN amplitude and phase predicted
by these models. It is possible to conclude, that the model of the author
provides the most realistic representation of the FCN variations. However, the
specified models are based on representation about single FCN rotational mode.
At the same time, some results of processing of the VLBI observations made
during last years, specify possible presence of two close FCN periods. A
theoretical explanation to presence of a second FCN frequency FCN has been
given by G. Krasinsky in his theory of rotation of the Earth with two-layer
liquid core, ERA2005. In the present work, for more detailed studying this
phenomenon, the IVS time series of celestial pole offset, and also those
predicted by the ERA2005 theory, have been investigated by means of several
statistical methods which confidently show presence of two fluctuations in
nutational movement of an Earth's rotation axis with the periods about -452 and
-410 solar days.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 17:51:47 GMT"
}
] | 2009-08-14T00:00:00 | [
[
"Malkin",
"Zinovy",
""
],
[
"Miller",
"Natalia",
""
]
] |
0704.3253 | Yi Zhao | Yi Zhao, Chi-Hang Fred Fung, Bing Qi, Christine Chen, and Hoi-Kwong Lo | Quantum Hacking: Experimental demonstration of time-shift attack against
practical quantum key distribution systems | 5 pages, 3 figures. Substantially revised version | Physical Review A, 78, 042333 (2008) | 10.1103/PhysRevA.78.042333 | null | quant-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Quantum key distribution (QKD) systems can send signals over more than 100 km
standard optical fiber and are widely believed to be secure. Here, we show
experimentally for the first time a technologically feasible attack, namely the
time-shift attack, against a commercial QKD system. Our result shows that,
contrary to popular belief, an eavesdropper, Eve, has a non-negligible
probability (~4%) to break the security of the system. Eve's success is due to
the well-known detection efficiency loophole in the experimental testing of
Bell inequalities. Therefore, the detection efficiency loophole plays a key
role not only in fundamental physics, but also in technological applications
such as QKD.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 18:06:00 GMT"
},
{
"version": "v2",
"created": "Mon, 17 Mar 2008 21:57:23 GMT"
},
{
"version": "v3",
"created": "Fri, 1 Apr 2011 21:01:36 GMT"
}
] | 2011-04-05T00:00:00 | [
[
"Zhao",
"Yi",
""
],
[
"Fung",
"Chi-Hang Fred",
""
],
[
"Qi",
"Bing",
""
],
[
"Chen",
"Christine",
""
],
[
"Lo",
"Hoi-Kwong",
""
]
] |
0704.3254 | Leonid Bedratyuk P. | Leonid Bedratyuk | Symmetrical invariants of some modular Lie algebras of Cartan type | 7 pages in Ukrainian | Mat. Stud. 30, No. 1, 3-8 (2008). | null | null | math.RA math.RT | null | Let $L$ be one of the finite dimensional Lie algebras $W_n({\bf m}),$
$S_n({\bf m}),$ $ H_n({\bf m})$ of Cartan type over an algebraically closed
field of prime characteristic $p>0.$ For an elements $F$ of the symmetrical
algebra $S(L)$ we found necessary and sufficient condition in order to the
element $ad(\partial_1)^{p^{m_1}-1} ad(\partial_2)^{p^{m_2}-1}...
ad(\partial_n)^{p^{m_n}-1}(F)$ belongs to the symmetrical invariants algebra
$S(L)^L.$ Also, for $p=3,5$ the algebra of symmetrical invariants
$S(H_2)^{H_2}$ is calculated in explicit way.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 17:48:54 GMT"
}
] | 2009-04-08T00:00:00 | [
[
"Bedratyuk",
"Leonid",
""
]
] |
0704.3255 | Frans Klinkhamer | C. Kaufhold, F. R. Klinkhamer | Vacuum Cherenkov radiation in spacelike Maxwell-Chern-Simons theory | 24 pages with revtex4, v5: published version | Phys.Rev.D76:025024,2007 | 10.1103/PhysRevD.76.025024 | KA-TP-10-2007 | hep-th astro-ph hep-ph | null | A detailed analysis of vacuum Cherenkov radiation in spacelike
Maxwell-Chern-Simons (MCS) theory is presented. A semiclassical treatment
reproduces the leading terms of the tree-level result from quantum field
theory. Moreover, certain quantum corrections turn out to be suppressed for
large energies of the charged particle, for example, the quantum corrections to
the classical MCS Cherenkov angle. It is argued that MCS-theory Cherenkov
radiation may, in principle, lead to anisotropy effects for ultra-high-energy
cosmic rays (UHECRs). In addition, a qualitative discussion of vacuum Cherenkov
radiation from a modified-Maxwell term in the action is given, together with
UHECR bounds on some of its dimensionless "coupling constants."
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 18:50:28 GMT"
},
{
"version": "v2",
"created": "Wed, 2 May 2007 17:30:12 GMT"
},
{
"version": "v3",
"created": "Mon, 28 May 2007 17:23:30 GMT"
},
{
"version": "v4",
"created": "Thu, 7 Jun 2007 18:09:42 GMT"
},
{
"version": "v5",
"created": "Mon, 23 Jul 2007 18:20:17 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Kaufhold",
"C.",
""
],
[
"Klinkhamer",
"F. R.",
""
]
] |
0704.3256 | Radu Laza | Radu Laza | The moduli space of cubic fourfolds | 28 pages, part I (the GIT compactification), the journal version | J. Algebraic Geom. 18 (2009), 511-545 | null | null | math.AG | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We describe the GIT compactification of the moduli space of cubic fourfolds,
with a special emphasis on the role played by singularities. Our main result is
that a cubic fourfold with only isolated simple (A-D-E) singularities is GIT
stable. Conversely, with some minor exceptions, the stability for cubic
fourfolds is characterized by this condition.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 17:54:25 GMT"
},
{
"version": "v2",
"created": "Thu, 4 Sep 2008 16:56:52 GMT"
}
] | 2011-09-28T00:00:00 | [
[
"Laza",
"Radu",
""
]
] |
0704.3257 | Caroline Bot | C. Bot, F. Boulanger, M. Rubio and F. Rantakyro | Millimeter dust continuum emission unveiling the true mass of giant
molecular clouds in the Small Magellanic Cloud | 10 pages, 2 figures, Astronomy & Astrophysics accepted | null | null | null | astro-ph | null | CO observations have been so far the best way to trace molecular gas in
external galaxies, but at low metallicity the gas mass deduced could be largely
underestimated. At present, the kinematic information of CO data cubes are used
to estimate virial masses and trace the total mass of the molecular clouds.
Millimeter dust emission can also be used as a dense gas tracer and could
unveil H2 envelopes lacking CO. These different tracers must be compared in
different environments. This study compares virial masses to masses deduced
from millimeter emission, in two GMC samples: the local molecular clouds in our
Galaxy and their equivalents in the Small Magellanic Cloud (SMC), one of the
nearest low metallicity dwarf galaxy. In our Galaxy, mass estimates deduced
from millimeter emission are consistent with masses deduced from gamma ray
analysis and trace the total mass of the clouds. Virial masses are
systematically larger (twice on average) than mass estimates from millimeter
dust emission. This difference decreases toward high masses and has already
been reported in previous studies. In the SMC however, molecular cloud masses
deduced from SIMBA millimeter observations are systematically higher (twice on
average for conservative values of the dust to gas ratio and dust emissivity)
than the virial masses from SEST CO observations. The observed excess can not
be accounted for by any plausible change of dust properties. Taking a general
form for the virial theorem, we show that a magnetic field strength of ~15
micro Gauss in SMC clouds could provide additional support to the clouds and
explain the difference observed. Masses of SMC molecular clouds have therefore
been underestimated so far. Magnetic pressure may contribute significantly to
their support.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 18:29:21 GMT"
}
] | 2019-08-19T00:00:00 | [
[
"Bot",
"C.",
""
],
[
"Boulanger",
"F.",
""
],
[
"Rubio",
"M.",
""
],
[
"Rantakyro",
"F.",
""
]
] |
0704.3258 | Rabindra N. Mohapatra | R. N. Mohapatra, N. Okada and Hai-Bo Yu | Natural Realizations of Seesaw in Mini-Warped Minimal SO(10) | 20 pages and one figure | Phys.Rev.D76:015013,2007 | 10.1103/PhysRevD.76.015013 | UMD-PP-07-003 | hep-ph | null | The minimal SUSY SO(10) GUT models with {\bf 10}, {\bf 126} and {\bf 210}
Higgs and only renormalizable couplings has been shown to provide a simple way
to understand the neutrino mixings as well as the ratio $\Delta
m^2_\odot/\Delta m^2_A$ in terms of quark mixing parameter $\theta_{Cabibbo}$,
provided neutrino masses are described by type II seesaw formula. However, in
this minimal picture, it is impossible to realize type II dominance with
renormalizable couplings in 4-dimensions. We show that this problem can be
cured by embedding this model into a warped 5-dimensional space time with
warping between the Planck and the GUT scale, where both type II as well as
mixed seesaw formulae can be realized in a natural manner without expanding the
Higgs sector. These models also avoid the possible problem of threshold effects
associated with large Higgs representations since the theory above the GUT
scale is now strongly coupled.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 18:37:19 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Mohapatra",
"R. N.",
""
],
[
"Okada",
"N.",
""
],
[
"Yu",
"Hai-Bo",
""
]
] |
0704.3259 | James P. Sethna | Christopher R. Myers, Ryan N. Gutenkunst, and James. P. Sethna | Python Unleashed on Systems Biology | Submitted to special issue of CiSE | null | null | null | q-bio.QM q-bio.MN | null | We have built an open-source software system for the modeling of biomolecular
reaction networks, SloppyCell, which is written in Python and makes substantial
use of third-party libraries for numerics, visualization, and parallel
programming. We highlight here some of the powerful features that Python
provides that enable SloppyCell to do dynamic code synthesis, symbolic
manipulation, and parallel exploration of complex parameter spaces.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 18:48:18 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Myers",
"Christopher R.",
""
],
[
"Gutenkunst",
"Ryan N.",
""
],
[
"Sethna",
"James. P.",
""
]
] |
0704.3260 | Marco Frasca | Marco Frasca | Spectrum of Yang-Mills Theory in D=3+1 | 6 pages, no figure. Updated references | null | null | null | hep-th hep-lat hep-ph math-ph math.MP | null | We give a comparison of the spectrum of Yang-Mills theory in $D=3+1$,
recently derived with a strong coupling expansion, with lattice data. We verify
excellent agreement also for 2$^{++}$ glueball. A deep analogy with the $D=2+1$
case is obtained and a full quantum theory of this approach is also given.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 18:57:19 GMT"
},
{
"version": "v2",
"created": "Fri, 18 May 2007 21:20:07 GMT"
},
{
"version": "v3",
"created": "Thu, 28 Jun 2007 06:13:01 GMT"
}
] | 2007-06-28T00:00:00 | [
[
"Frasca",
"Marco",
""
]
] |
0704.3261 | Gerard Le Caer | G. Le Caer, C. Male and R. Delannay | Nearest-neigbor spacing distributions of the beta-Hermite ensemble of
random matrices | Physica A (in press, 2007), 32 pages, 13 figures, corresponding
author:G. Le Caer | null | 10.1016/j.physa.2007.04.057 | null | cond-mat.stat-mech cond-mat.dis-nn | null | The distributions of the spacing s between nearest-neighbor levels of
unfolded spectra of random matrices from the beta-Hermite ensemble (beta-HE) is
investigated by Monte Carlo simulations. The random matrices from the beta-HE
are real-symmetric and tridiagonal where beta, which can take any positive
value, is the reciprocal of the temperature in the classical electrostatic
interpretation of eigenvalues. Generalized gamma distributions are shown to be
excellent approximations of the nearest-neighbor spacing (NNS) distributions
for any beta while being still simple. They account both for the level
repulsion when s tends to zero and for the whole shape of the NNS distributions
in the range of s which is accessible to experiment or to most numerical
simulations. The exact NNS distribution of the GOE (beta=1) is in particular
significantly better described by a generalized gamma distribution than it is
by the Wigner surmise while the best generalized gamma approximation coincides
essentially with the Wigner surmise for beta larger than ~2. The distributions
of the minimum NN spacing between eigenvalues of matrices from the beta-HE,
obtained both from as-calculated eigenvalues and from unfolded eigenvalues are
Brody distributions.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 18:56:56 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Caer",
"G. Le",
""
],
[
"Male",
"C.",
""
],
[
"Delannay",
"R.",
""
]
] |
0704.3262 | Rainer Schmidt | Rainer Schmidt, Wilma Eerenstein, Thomas Winiecki, Finlay D. Morrison,
Paul A. Midgley | Impedance spectroscopy of epitaxial multiferroic thin films | null | Physical Review B 75, 245111 (2007) | 10.1103/PhysRevB.75.245111 | null | cond-mat.str-el cond-mat.mtrl-sci | null | Temperature dependent impedance spectroscopy enables the many contributions
to the dielectric and resistive properties of condensed matter to be
deconvoluted and characterized separately. We have achieved this for
multiferroic epitaxial thin films of BiFeO3 (BFO) and BiMnO3 (BMO), key
examples of materials with strong magneto-electric coupling. We demonstrate
that the true film capacitance of the epitaxial layers is similar to that of
the electrode interface, making analysis of capacitance as a function of film
thickness necessary to achieve deconvolution. We modeled non-Debye impedance
response using Gaussian distributions of relaxation times and reveal that
conventional resistivity measurements on multiferroic layers may be dominated
by interface effects. Thermally activated charge transport models yielded
activation energies of 0.60 eV +- 0.05 eV (BFO) and 0.25 eV +- 0.03 eV (BMO),
which is consistent with conduction dominated by oxygen vacancies (BFO) and
electron hopping (BMO). The intrinsic film dielectric constants were determined
to be 320 +- 75 (BFO) and 450 +- 100 (BMO).
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 19:13:19 GMT"
}
] | 2007-06-20T00:00:00 | [
[
"Schmidt",
"Rainer",
""
],
[
"Eerenstein",
"Wilma",
""
],
[
"Winiecki",
"Thomas",
""
],
[
"Morrison",
"Finlay D.",
""
],
[
"Midgley",
"Paul A.",
""
]
] |
0704.3263 | Dominique Jean-Marie Mornet | Karim Hnia, G\'erald Hugon, Ahmed Masmoudi, Jacques Mercier,
Fran\c{c}ois Rivier, Dominique Jean-Marie Mornet | Effect of beta-Dystroglycan Processing on Utrophin / DP116 Anchorage in
Normal and MDX Mouse Schwann Cell Membrane | null | Neuroscience 141 (18/04/2006) 607-620 | 10.1016/J.neuroscience.2006.04.043 | null | q-bio.NC | null | In the peripheral nervous system, utrophin and the short dystrophin isoform
(Dp116) are co-localized at the outermost layer of the myelin sheath of nerve
fibers; together with the dystroglycan complex. In peripheral nerve, matrix
metalloproteinase (MMP) creates a 30 kDa fragment of beta-dystroglycan, leading
to a disruption of the link between the extracellular matrix and the cell
membrane. Here we asked if the processing of the beta-dystroglycan could
influence the anchorage of Dp116 or/and utrophin in normal and mdx Schwann cell
membrane. We showed that MMP-9 was more activated in mdx nerve than in
wild-type one. This activation leads to an accumulation of the 30 kDa
beta-dystroglycan isoform and have an impact on the anchorage of Dp116 and
utrophin isoforms in mdx Schwann cells membrane. Our results showed that Dp116
had greater affinity to the full length form of beta-dystroglycan than the 30
kDa form. Moreover, we showed for the first time that the short isoform of
utrophin (Up71) was over-expressed in mdx Schwann cells compared to wild-type.
In addition, this utrophin isoform (Up71) seems to have greater affinity to the
30 kDa beta-dystroglycan which could explain a more stabilization of this 30
kDa at the membrane compartment. Our results highlight the potential
participation of the short utrophin isoform and the cleaved form of
beta-dystroglycan in mdx Schwann cell membrane architecture.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 19:17:45 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Hnia",
"Karim",
""
],
[
"Hugon",
"Gérald",
""
],
[
"Masmoudi",
"Ahmed",
""
],
[
"Mercier",
"Jacques",
""
],
[
"Rivier",
"François",
""
],
[
"Mornet",
"Dominique Jean-Marie",
""
]
] |
0704.3264 | Jose Vilar | Leonor Saiz and Jose M. G. Vilar | Efficiency and versatility of distal multisite transcription regulation | null | null | null | null | q-bio.SC q-bio.MN | null | Transcription regulation typically involves the binding of proteins over long
distances on multiple DNA sites that are brought close to each other by the
formation of DNA loops. The inherent complexity of the assembly of regulatory
complexes on looped DNA challenges the understanding of even the simplest
genetic systems, including the prototypical lac operon. Here we implement a
scalable quantitative computational approach to analyze systems regulated
through multiple DNA sites with looping. Our approach applied to the lac operon
accurately predicts the transcription rate over five orders of magnitude for
wild type and seven mutants accounting for all the combinations of deletions of
the three operators. A quantitative analysis of the model reveals that the
presence of three operators provides a mechanism to combine robust repression
with sensitive induction, two seemingly mutually exclusive properties that are
required for optimal functioning of metabolic switches.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 19:46:28 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Saiz",
"Leonor",
""
],
[
"Vilar",
"Jose M. G.",
""
]
] |
0704.3265 | Michael Ibison | M. Ibison | Static forms of the Robertson-Walker spacetimes | null | null | null | null | gr-qc | null | It is shown that only the maximally-symmetric spacetimes can be expressed in
both the Robertson-Walker form and in static form - there are no other static
forms of the Robertson-Walker spacetimes. All possible static forms of the
metric of the maximally-symmetric spacetimes are presented as a table. The
findings are generalized to apply to functionally more general spacetimes: it
is shown that the maximally symmetric spacetimes are also the only spacetimes
that can be written in both orthogonal-time isotropic form and in static form.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 19:55:14 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Ibison",
"M.",
""
]
] |
0704.3266 | Alexander Scholz | Aleks Scholz (SUPA, University of St. Andrews), Jaime Coffey
(University of British Columbia), Alexis Brandeker (Stockholm Observatory),
Ray Jayawardhana (University of Toronto) | Rotation and activity of pre-main-sequence stars | 40 pages, 8 figures, ApJ, in press | null | 10.1086/518361 | null | astro-ph | null | We present a study of rotation (vsini) and chromospheric activity (Halpha EW)
based on an extensive set of high-resolution optical spectra obtained with MIKE
on the 6.5m Magellan Clay telescope. Our targets are 74 F-M dwarfs in the young
stellar associations Eta Cha, TW Hydrae, Beta Pic, and Tuc-Hor, spanning ages
from 6 to 30 Myr. While the Halpha EW for most F and G stars are consistent
with pure photospheric absorption, most K and M stars show chromospheric
emission. By comparing Halpha EW in our sample to results in the literature, we
see a clear evolutionary sequence: Chromospheric activity declines steadily
from the T Tauri phase to the main sequence. Using activity as an age
indicator, we find a plausible age range for the Tuc-Hor association of 10-40
Myr. Between 5 and 30 Myr, we do not see evidence for rotational braking in the
total sample, thus angular momentum is conserved, in contrast to younger stars.
This difference indicates a change in the rotational regulation at 5-10 Myr,
possibly because disk braking cannot operate longer than typical disk
lifetimes, allowing the objects to spin up. The rotation-activity relation is
flat in our sample; in contrast to main-sequence stars, there is no linear
correlation for slow rotators. We argue that this is because young stars
generate their magnetic fields in a fundamentally different way from
main-sequence stars, and not just the result of a saturated solar-type dynamo.
By comparing our rotational velocities with published rotation periods for a
subset of stars, we determine ages of 13 (7-20) Myr and 9 (7-17} Myr for the
Eta Cha and TWA associations, respectively, consistent with previous estimates.
Thus we conclude that stellar radii from evolutionary models by Baraffe et al.
(1998) are in agreement with the observed radii within +-15%. (abridged)
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 20:09:31 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Scholz",
"Aleks",
"",
"SUPA, University of St. Andrews"
],
[
"Coffey",
"Jaime",
"",
"University of British Columbia"
],
[
"Brandeker",
"Alexis",
"",
"Stockholm Observatory"
],
[
"Jayawardhana",
"Ray",
"",
"University of Toronto"
]
] |
0704.3267 | Justin Read | J. I. Read, P. Saha, and A. V. Maccio | Radial density profiles of time-delay lensing galaxies | Replaced with final version accepted for publication in ApJ; very
minor changes to text; high resolution figures may be obtained at
justinread.net | null | 10.1086/520714 | null | astro-ph | null | We present non-parametric radial mass profiles for ten QSO strong lensing
galaxies. Five of the galaxies have profiles close to $\rho(r)\propto r^{-2}$,
while the rest are closer to r^{-1}, consistent with an NFW profile. The former
are all relatively isolated early-types and dominated by their stellar light.
The latter --though the modeling code did not know this-- are either in
clusters, or have very high mass-to-light, suggesting dark-matter dominant
lenses (one is a actually pair of merging galaxies). The same models give
$H_0^{-1} = 15.2_{-1.7}^{+2.5}\Gyr$ ($H_0 = 64_{-9}^{+8} \legacy$), consistent
with a previous determination. When tested on simulated lenses taken from a
cosmological hydrodynamical simulation, our modeling pipeline recovers both H_0
and $\rho(r)$ within estimated uncertainties. Our result is contrary to some
recent claims that lensing time delays imply either a low H_0 or galaxy
profiles much steeper than r^{-2}. We diagnose these claims as resulting from
an invalid modeling approximation: that small deviations from a power-law
profile have a small effect on lensing time-delays. In fact, as we show using
using both perturbation theory and numerical computation from a
galaxy-formation simulation, a first-order perturbation of an isothermal lens
can produce a zeroth-order change in the time delays.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 20:12:37 GMT"
},
{
"version": "v2",
"created": "Tue, 31 Jul 2007 13:44:06 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Read",
"J. I.",
""
],
[
"Saha",
"P.",
""
],
[
"Maccio",
"A. V.",
""
]
] |
0704.3268 | Koray Karahaliloglu | Koray Karahaliloglu | 2D Path Solutions from a Single Layer Excitable CNN Model | 24 pages, 9 figures | null | null | null | cs.RO cs.NE | null | An easily implementable path solution algorithm for 2D spatial problems,
based on excitable/programmable characteristics of a specific cellular
nonlinear network (CNN) model is presented and numerically investigated. The
network is a single layer bioinspired model which was also implemented in CMOS
technology. It exhibits excitable characteristics with regionally bistable
cells. The related response realizes propagations of trigger autowaves, where
the excitable mode can be globally preset and reset. It is shown that, obstacle
distributions in 2D space can also be directly mapped onto the coupled cell
array in the network. Combining these two features, the network model can serve
as the main block in a 2D path computing processor. The related algorithm and
configurations are numerically experimented with circuit level parameters and
performance estimations are also presented. The simplicity of the model also
allows alternative technology and device level implementation, which may become
critical in autonomous processor design of related micro or nanoscale robotic
applications.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 20:20:46 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Karahaliloglu",
"Koray",
""
]
] |
0704.3269 | Ian Dobbs-Dixon | Ian Dobbs-Dixon and D.N.C. Lin | Atmospheric Dynamics of Short-period Extra Solar Gas Giant Planets I:
Dependence of Night-Side Temperature on Opacity | 35 Pages, 13 Figures | null | 10.1086/523786 | null | astro-ph | null | More than two dozen short-period Jupiter-mass gas giant planets have been
discovered around nearby solar-type stars in recent years, several of which
undergo transits, making them ideal for the detection and characterization of
their atmospheres. Here we adopt a three-dimensional radiative hydrodynamical
numerical scheme to simulate atmospheric circulation on close-in gas giant
planets. In contrast to the conventional GCM and shallow water algorithms, this
method does not assume quasi hydrostatic equilibrium and it approximates
radiation transfer from optically thin to thick regions with flux-limited
diffusion. In the first paper of this series, we consider
synchronously-spinning gas giants. We show that a full three-dimensional
treatment, coupled with rotationally modified flows and an accurate treatment
of radiation, yields a clear temperature transition at the terminator. Based on
a series of numerical simulations with varying opacities, we show that the
night-side temperature is a strong indicator of the opacity of the planetary
atmosphere. Planetary atmospheres that maintain large, interstellar opacities
will exhibit large day-night temperature differences, while planets with
reduced atmospheric opacities due to extensive grain growth and sedimentation
will exhibit much more uniform temperatures throughout their photosphere's. In
addition to numerical results, we present a four-zone analytic approximation to
explain this dependence.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 20:23:57 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Dobbs-Dixon",
"Ian",
""
],
[
"Lin",
"D. N. C.",
""
]
] |
0704.3270 | James Stewart | The HERMES Collaboration: A. Airapetian, et al | Hadronization in semi-inclusive deep-inelastic scattering on nuclei | 33 pages, 12 figures | Nucl.Phys.B780:1-27,2007 | 10.1016/j.nuclphysb.2007.06.004 | DESY 07-050 | hep-ex | null | A series of semi-inclusive deep-inelastic scattering measurements on
deuterium, helium, neon, krypton, and xenon targets has been performed in order
to study hadronization. The data were collected with the HERMES detector at the
DESY laboratory using a 27.6 GeV positron or electron beam. Hadron
multiplicities on nucleus A relative to those on the deuteron, R_A^h, are
presented for various hadrons (\pi^+, \pi^-, \pi^0, K^+, K^-, p, and \bar{p})
as a function of the virtual-photon energy \nu, the fraction z of this energy
transferred to the hadron, the photon virtuality Q^2, and the hadron transverse
momentum squared p_t^2. The data reveal a systematic decrease of R_A^h with the
mass number A for each hadron type h. Furthermore, R_A^h increases (decreases)
with increasing values of \nu (z), increases slightly with increasing Q^2, and
is almost independent of p_t^2, except at large values of p_t^2. For pions
two-dimensional distributions also are presented. These indicate that the
dependences of R_A^{\pi} on \nu and z can largely be described as a dependence
on a single variable L_c, which is a combination of \nu and z. The dependence
on L_c suggests in which kinematic conditions partonic and hadronic mechanisms
may be dominant. The behaviour of R_A^{\pi} at large p_t^2 constitutes
tentative evidence for a partonic energy-loss mechanism. The A-dependence of
R_A^h is investigated as a function of \nu, z, and of L_c. It approximately
follows an A^{\alpha} form with \alpha \approx 0.5 - 0.6.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 20:29:31 GMT"
}
] | 2012-08-03T00:00:00 | [
[
"The HERMES Collaboration",
"",
""
],
[
"Airapetian",
"A.",
""
]
] |
0704.3271 | Kathryn Zurek | Alexander Friedland, Kathryn M. Zurek, Sergei Bashinsky | Constraining Models of Neutrino Mass and Neutrino Interactions with the
Planck Satellite | 25 pages, 16 figures, revtex | null | null | null | astro-ph hep-ph | null | In several classes of particle physics models -- ranging from the classical
Majoron models, to the more recent scenarios of late neutrino masses or
Mass-Varying Neutrinos -- one or more of the neutrinos are postulated to couple
to a new light scalar field. As a result of this coupling, neutrinos in the
early universe instead of streaming freely could form a self-coupled fluid,
with potentially observable signatures in the Cosmic Microwave Background and
the large scale structure of the universe. We re-examine the constraints on
this scenario from the presently available cosmological data and investigate
the sensitivity expected from the Planck satellite. In the first case, we find
that the sensitivity strongly depends on which piece of data is used. The SDSS
Main sample data, combined with WMAP and other data, disfavors the scenario of
three coupled neutrinos at about the 3.5$\sigma$ confidence level, but also
favors a high number of freely streaming neutrinos, with the best fit at 5.2.
If the matter power spectrum is instead taken from the SDSS Large Red Galaxy
sample, best fit point has 2.5 freely streaming neutrinos, but the scenario
with three coupled neutrinos becomes allowed at $2\sigma$. In contrast, Planck
alone will exclude even a single self-coupled neutrino at the $4.2\sigma$
confidence level, and will determine the total radiation at CMB epoch to
$\Delta N_\nu^{eff} = ^{+0.5}_{-0.3}$ ($1\sigma$ errors). We investigate the
robustness of this result with respect to the details of Planck's detector.
This sensitivity to neutrino free-streaming implies that Planck will be capable
of probing a large region of the Mass-Varying Neutrino parameter space. Planck
may also be sensitive to a scale of neutrino mass generation as high as 1 TeV.
| [
{
"version": "v1",
"created": "Wed, 25 Apr 2007 18:58:06 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Friedland",
"Alexander",
""
],
[
"Zurek",
"Kathryn M.",
""
],
[
"Bashinsky",
"Sergei",
""
]
] |
0704.3272 | Fernando Marchesano | Fernando Marchesano and Waldemar Schulgin | Non-geometric fluxes as supergravity backgrounds | 5 pages. Further typos corrected | Phys.Rev.D76:041901,2007 | 10.1103/PhysRevD.76.041901 | LMU-ASC 26/07, MPP-2007-49 | hep-th | null | We consider examples of D=4 string theory vacua which, although globally
non-geometric, admit a local description in terms of D=10 supergravity
backgrounds. We analyze such backgrounds and find that the supersymmetry
spinors vary non-trivially along the internal manifold, reproducing the
interpolating supergravity solutions found by Frey and Grana. Finally, we
propose a simple, local expression for non-geometric fluxes in terms of the
internal spinors of the compactification.
| [
{
"version": "v1",
"created": "Wed, 25 Apr 2007 18:20:28 GMT"
},
{
"version": "v2",
"created": "Wed, 9 May 2007 16:43:15 GMT"
},
{
"version": "v3",
"created": "Wed, 19 Sep 2007 15:03:25 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Marchesano",
"Fernando",
""
],
[
"Schulgin",
"Waldemar",
""
]
] |
0704.3273 | Siu Chin | Siu A. Chin | Forward and non-forward symplectic integrators in solving classical
dynamics problems | 26 pages, 17 figures, to be published in a "Special Issue on
Splitting Methods for Differential Equation", Intl. J. of Comp. Math | null | null | null | physics.comp-ph physics.class-ph | null | Forward time step integrators are splitting algorithms with only positive
splitting coefficients. When used in solving physical evolution equations,
these positive coefficients correspond to positive time steps. Forward
algorithms are essential for solving time-irreversible equations that cannot be
evolved using backward time steps. However, forward integrators are also better
in solving time-reversible equations of classical dynamics by tracking as
closely as possible the physical trajectory. This work compares in detail
various forward and non-forward fourth-order integrators using three, fourth,
five and six force evaluations. In the case of solving the 2D Kepler orbit, all
non-forward integrators are optimized by simply minimizing the size of their
backward time steps.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 20:42:25 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Chin",
"Siu A.",
""
]
] |
0704.3274 | Mladen Georgiev | Fabio DeMatteis and Mladen Georgiev | Nonradiative DKR processes: revisiting the theory. I. Unimode model | 17 pages including 1 table, 2 appendices and 1 figure, all pdf format | null | null | null | cond-mat.mtrl-sci | null | We are revisiting the efficiency problem of DKR nonradiative transitions at
local electronic centers in polarizable solids. Following a brief survey, we
formulate the general rate equations thereby defining the microscopic
parameters controlling the nonradiative deexcitation. We also reproduce the
quantum mechanical expressions for the energy conserving "horizontal transfer
rates" to compare with the "verical transition rates" at various vibronic
energy levels.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 20:59:44 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"DeMatteis",
"Fabio",
""
],
[
"Georgiev",
"Mladen",
""
]
] |
0704.3275 | Wei Zhang | Wei Zhang and C. A. R. Sa de Melo | Matter-wave interference in s-wave and p-wave Fermi condensates | 8 pages, 5 figures; Phys. Rev. A 76, 013627 (2007) | Phys. Rev. A 76, 013627 (2007) | 10.1103/PhysRevA.76.013627 | null | cond-mat.str-el cond-mat.supr-con | null | We discuss the time evolution and matter-wave interference of Fermi
condensates on the BEC side of Feshbach resonances for s and p-wave
superfluids, upon release from harmonic traps. In swave systems, where the
order parameter is a complex scalar, we find that the interference patterns
depend on the relative phase of the order parameters of the condensates. In
p-wave systems involving the mixture of two-hyperfine states, we show that the
interference pattern exhibits a polarization effect depending on the relative
orientation of the two vector order parameters. Lastly, we also point out that
p-wave Fermi condensates exhibit an anisotropic expansion, reflecting the
spatial anisotropy of the underlying interaction between fermions and the
orbital nature of the vector order parameter. Potential applications of our
results include systems of ultra-cold atoms that exhibit p-wave Feshbach
resonances such as 6Li or 40K.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 21:20:57 GMT"
},
{
"version": "v2",
"created": "Wed, 21 May 2008 16:52:05 GMT"
}
] | 2008-05-21T00:00:00 | [
[
"Zhang",
"Wei",
""
],
[
"de Melo",
"C. A. R. Sa",
""
]
] |
0704.3276 | Frank Tipler | Frank J. Tipler | Feynman-Weinberg Quantum Gravity and the Extended Standard Model as a
Theory of Everything | null | Rept.Prog.PHys.68:897-964,2005 | 10.1088/0034-4885/68/4/R04 | null | hep-th | null | I argue that the (extended) Standard Model (SM) of particle physics and the
renormalizable Feynman-Weinberg theory of quantum gravity comprise a theory of
everything. I show that imposing the appropriate cosmological boundary
conditions make the theory finite. The infinities that are normally
renormalized away and the series divergence infinities are both eliminated by
the same mechanism. Furthermore, this theory can resolve the horizon, flatness,
and isotropy problems of cosmology. Joint mathematical consistency naturally
yields a scale-free, Gaussian, adiabatic perturbation spectrum, and more matter
than antimatter. I show that mathematical consistency of the theory requires
the universe to begin at an initial singularity with a pure $SU(2)_L$ gauge
field. I show that quantum mechanics requires this field to have a Planckian
spectrum whatever its temperature. If this field has managed to survive
thermalization to the present day, then it would be the CMBR. If so, then we
would have a natural explanation for the dark matter and the dark energy. I
show that isotropic ultrahigh energy (UHE) cosmic rays are explained if the
CMBR is a pure $SU(2)_L$ gauge field. The $SU(2)_L$ nature of the CMBR may have
been seen in the Sunyaev-Zel'dovich effect. I propose several simple
experiments to test the hypothesis.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 21:44:28 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Tipler",
"Frank J.",
""
]
] |
0704.3277 | Michael Ibison | M. Ibison | Tachyons and superluminal boosts | Slightly revised from earlier publication with J. Em. P | null | null | null | physics.gen-ph physics.class-ph | null | Some arguments in favour of the existence of tachyons and extensions of the
Lorentz Group are presented. On the former, it is observed that with a slight
modification to standard electromagnetic theory a single superluminal charge
will bind to itself in a self-sustaining circular orbit, suggestive of a
(modified) electromagnetic interpretation of the strong force. Symmetries in
that theory are used in the subsequent analysis as a starting point in the
search for physically-motivated extensions of the Lorentz Group. There is some
discussion of the validity of imaginary coordinates in superluminal
transformations of frame. The article concludes with some speculation on the
implications for faster-than light travel.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 22:02:13 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Ibison",
"M.",
""
]
] |
0704.3278 | Travis Schedler | Travis Schedler | Zeroth Hochschild homology of preprojective algebras over the integers | 69 pages, 2 figures; final pre-publication version; many corrections
and improvements throughout. Note though the first version has additional
results (for instance, it computes the higher Hochschild (co)homology and its
structures) | null | null | null | math.RT math.QA | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We determine the Z-module structure of the preprojective algebra and its
zeroth Hochschild homology, for any non-Dynkin quiver (and hence the structure
working over any base commutative ring, of any characteristic). This answers
(and generalizes) a conjecture of Hesselholt and Rains, producing new
$p$-torsion classes in degrees 2p^l, l >= 1, We relate these classes by p-th
power maps and interpret them in terms of the kernel of Verschiebung maps from
noncommutative Witt theory. An important tool is a generalization of the
Diamond Lemma to modules over commutative rings, which we give in the appendix.
In the previous version, additional results are included, such as: the
Poisson center of $\text{Sym } HH_0(\Pi)$ for all quivers, the BV algebra
structure on Hochschild cohomology, including how the Lie algebra structure
$HH_0(\Pi_Q)$ naturally arises from it, and the cyclic homology groups of
$\Pi_Q$.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 22:05:29 GMT"
},
{
"version": "v2",
"created": "Tue, 16 Feb 2016 11:37:10 GMT"
},
{
"version": "v3",
"created": "Sat, 28 May 2016 07:36:28 GMT"
}
] | 2016-05-31T00:00:00 | [
[
"Schedler",
"Travis",
""
]
] |
0704.3279 | Michael Ibison | M. Ibison | Un-renormalized Classical Electromagnetism | null | Annals of Physics 321 No. 2, pp. 261-305 (2006) | 10.1016/j.aop.2005.05.002 | null | physics.gen-ph physics.class-ph | null | This paper follows in the tradition of direct-action versions of
electromagnetism having the aim of avoiding a balance of infinities wherein a
mechanical mass offsets an infinite electromagnetic mass so as to arrive at a
finite observed value. Given that, in this respect the direct-action approached
ultimately failed because its initial exclusion of self-action was found to be
untenable in the relativistic domain, this paper continues the tradition
considering instead a version of electromagnetism wherein mechanical action is
excluded and self-action is retained. It is shown that the resulting theory is
effectively interacting due to the presence of infinite forces. A vehicle for
the investigation is a pair of classical point charges in a positronium-like
arrangement for which the orbits are found to be self-sustaining and naturally
quantized.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 22:37:36 GMT"
}
] | 2015-05-13T00:00:00 | [
[
"Ibison",
"M.",
""
]
] |
0704.3280 | Jeng-Daw Yu | Jeng-Daw Yu | Local structure of the moduli space of K3 surfaces over finite
characteristic | 10 pages | null | null | null | math.AG | null | Let k be a perfect field of characteristic p > 2. In this note, we show that
the local moduli space of a non-supersingular K3 surface over k with trivial
deformation of the associated enlarged formal Brauer group admits a natural
p-divisible formal group structure.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 22:40:29 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Yu",
"Jeng-Daw",
""
]
] |
0704.3281 | Arthur Berg | Arthur Berg and Dimitris N Politis and Kagba Suaray and Hui Zeng | Reduced bias nonparametric lifetime density and hazard estimation | 21 pages, 4 figures | null | null | null | math.ST stat.TH | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Kernel-based nonparametric hazard rate estimation is considered with a
special class of infinite-order kernels that achieves favorable bias and mean
square error properties. A fully automatic and adaptive implementation of a
density and hazard rate estimator is proposed for randomly right censored data.
Careful selection of the bandwidth in the proposed estimators yields estimates
that are more efficient in terms of overall mean squared error performance, and
in some cases achieves a nearly parametric convergence rate. Additionally,
rapidly converging bandwidth estimates are presented for use in second-order
kernels to supplement such kernel-based methods in hazard rate estimation.
Simulations illustrate the improved accuracy of the proposed estimator against
other nonparametric estimators of the density and hazard function. A real data
application is also presented on survival data from 13,166 breast carcinoma
patients.
| [
{
"version": "v1",
"created": "Wed, 25 Apr 2007 01:45:51 GMT"
},
{
"version": "v2",
"created": "Tue, 16 Oct 2018 14:22:00 GMT"
}
] | 2018-10-17T00:00:00 | [
[
"Berg",
"Arthur",
""
],
[
"Politis",
"Dimitris N",
""
],
[
"Suaray",
"Kagba",
""
],
[
"Zeng",
"Hui",
""
]
] |
0704.3282 | Andrii Neronov | A.Neronov, F.Aharonian | Production of TeV gamma-radiation in the vicinity of the supermassive
black hole in the giant radiogalaxy M87 | 11 pages, ApJ, in print | null | 10.1086/522199 | null | astro-ph | null | Although the giant radiogalaxy M 87 harbors many distinct regions of
broad-band nonthermal emission, the recently reported fast variability of TeV
gamma rays from M 87 on a timescale of days strongly constrains the range of
speculations concerning the possible sites and scenarios of particle
acceleration responsible for the observed TeV emission. A natural production
site of this radiation is the immediate vicinity of the central supermassive
mass black hole (BH). Because of the low bolometric luminosity, the nucleus of
M 87 is effectively transparent for gamma rays up to energy of 10 TeV, which
makes this source an ideal laboratory for study of particle acceleration
processes close to the BH event horizon. We critically analyse different
possible radiation mechanisms in this region, and argue that the observed very
high-energy gamma ray emission can be explained by the inverse Compton emission
of ultrarelativistic electron-positron pairs produced through the development
of an electromagnetic cascade in the BH magnetosphere. We demonstrate, through
detailed numerical calculations of acceleration and radiation of electrons in
the magnetospheric vacuum gap, that this ``pulsar magnetosphere like'' scenario
can satisfactorily explain the main properties of TeV gamma-ray emission of M
87.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 23:18:22 GMT"
},
{
"version": "v2",
"created": "Tue, 7 Aug 2007 11:41:42 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Neronov",
"A.",
""
],
[
"Aharonian",
"F.",
""
]
] |
0704.3283 | Uwe Nagel | Uwe Nagel, Tim Roemer | Glicci simplicial complexes | null | null | null | null | math.AC math.CO | null | One of the main open questions in liaison theory is whether every homogeneous
Cohen-Macaulay ideal in a polynomial ring is glicci, i.e. if it is in the
G-liaison class of a complete intersection. We give an affirmative answer to
this question for Stanley-Reisner ideals defined by simplicial complexes that
are weakly vertex-decomposable. This class of complexes includes matroid,
shifted and Gorenstein complexes respectively. Moreover, we construct a
simplicial complex which shows that the property of being glicci depends on the
characteristic of the base field. As an application of our methods we establish
new evidence for two conjectures of Stanley on partitionable complexes and on
Stanley decompositions.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 23:48:27 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Nagel",
"Uwe",
""
],
[
"Roemer",
"Tim",
""
]
] |
0704.3284 | Ricardo Carretero | G. Herring, P.G. Kevrekidis, B.A. Malomed, R. Carretero-Gonzalez, D.J.
Frantzeskakis | Symmetry Breaking in Linearly Coupled Dynamical Lattices | 9 pages, 9 figures, submitted to Phys. Rev. E, Apr, 2007 | Phys. Rev. E 76 (2007) 066606 | 10.1103/PhysRevE.76.066606 | null | nlin.PS | null | We examine one- and two-dimensional (1D and 2D) models of linearly coupled
lattices of the discrete-nonlinear-Schr{\"{o}}dinger type. Analyzing ground
states of the systems with equal powers in the two components, we find a
symmetry-breaking phenomenon beyond a critical value of the squared $l^2$-norm.
Asymmetric states, with unequal powers in their components, emerge through a
subcritical pitchfork bifurcation, which, for very weakly coupled lattices,
changes into a supercritical one. We identify the stability of various solution
branches. Dynamical manifestations of the symmetry breaking are studied by
simulating the evolution of the unstable branches. The results present the
first example of spontaneous symmetry breaking in 2D lattice solitons. This
feature has no counterpart in the continuum limit, because of the collapse
instability in the latter case.
| [
{
"version": "v1",
"created": "Wed, 25 Apr 2007 00:00:48 GMT"
}
] | 2010-12-10T00:00:00 | [
[
"Herring",
"G.",
""
],
[
"Kevrekidis",
"P. G.",
""
],
[
"Malomed",
"B. A.",
""
],
[
"Carretero-Gonzalez",
"R.",
""
],
[
"Frantzeskakis",
"D. J.",
""
]
] |
0704.3285 | Daniel J. H. Chung | Daniel J. H. Chung, Lisa L. Everett, and Konstantin T. Matchev | Inflationary Cosmology Connecting Dark Energy and Dark Matter | 16 pages, 3 figures | Phys.Rev.D76:103530,2007 | 10.1103/PhysRevD.76.103530 | MADPH-07-1487, UFIFT-HEP-07-5 | hep-ph astro-ph hep-th | null | Kination dominated quintessence models of dark energy have the intriguing
feature that the relic abundance of thermal cold dark matter can be
significantly enhanced compared to the predictions from standard cosmology.
Previous treatments of such models do not include a realistic embedding of
inflationary initial conditions. We remedy this situation by constructing a
viable inflationary model in which the inflaton and quintessence field are the
same scalar degree of freedom. Kination domination is achieved after inflation
through a strong push or "kick" of the inflaton, and sufficient reheating can
be achieved depending on model parameters. This allows us to explore both
model-dependent and model-independent cosmological predictions of this
scenario. We find that measurements of the B-mode CMB polarization can rule out
this class of scenarios almost model independently. We also discuss other
experimentally accessible signatures for this class of models.
| [
{
"version": "v1",
"created": "Tue, 24 Apr 2007 23:54:54 GMT"
},
{
"version": "v2",
"created": "Tue, 9 Oct 2007 19:20:48 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Chung",
"Daniel J. H.",
""
],
[
"Everett",
"Lisa L.",
""
],
[
"Matchev",
"Konstantin T.",
""
]
] |
0704.3286 | Thomas Fleming | Thomas Fleming | Milnor Invariants for Spatial Graphs | 11 pages, 5 figures | null | null | null | math.GT | null | Link homotopy has been an active area of research for knot theorists since
its introduction by Milnor in the 1950s. We introduce a new equivalence
relation on spatial graphs called component homotopy, which reduces to link
homotopy in the classical case. Unlike previous attempts at generalizing link
homotopy to spatial graphs, our new relation allows analogues of some standard
link homotopy results and invariants.
In particular we can define a type of Milnor group for a spatial graph under
component homotopy, and this group determines whether or not the spatial graph
is splittable. More surprisingly, we will also show that whether the spatial
graph is splittable up to component homotopy depends only on the link homotopy
class of the links contained within it. Numerical invariants of the relation
will also be produced.
| [
{
"version": "v1",
"created": "Wed, 25 Apr 2007 00:43:34 GMT"
}
] | 2009-09-29T00:00:00 | [
[
"Fleming",
"Thomas",
""
]
] |
0704.3287 | N. Raj Rao | N. Raj Rao, Alan Edelman | Sample size cognizant detection of signals in white noise | To appear in the Proceedings of the 8th IEEE International Workshop
on Signal Processing Advances in Wireless Communications (SPAWC), Helsinki,
Finland, June 17-20, 2007 | null | null | null | cs.IT math.IT | null | The detection and estimation of signals in noisy, limited data is a problem
of interest to many scientific and engineering communities. We present a
computationally simple, sample eigenvalue based procedure for estimating the
number of high-dimensional signals in white noise when there are relatively few
samples. We highlight a fundamental asymptotic limit of sample eigenvalue based
detection of weak high-dimensional signals from a limited sample size and
discuss its implication for the detection of two closely spaced signals.
This motivates our heuristic definition of the 'effective number of
identifiable signals.' Numerical simulations are used to demonstrate the
consistency of the algorithm with respect to the effective number of signals
and the superior performance of the algorithm with respect to Wax and Kailath's
"asymptotically consistent" MDL based estimator.
| [
{
"version": "v1",
"created": "Wed, 25 Apr 2007 00:23:20 GMT"
}
] | 2007-07-13T00:00:00 | [
[
"Rao",
"N. Raj",
""
],
[
"Edelman",
"Alan",
""
]
] |
0704.3288 | Roland Kothes | P.P. Kronberg, R. Kothes, C.J. Salter, P. Perillat | Discovery of new faint radio emission on 8$\arcdeg$ to 3$\arcmin$ scales
in the Coma field, and some Galactic and extragalactic implications | 12 pages, published in ApJ | Astrophys.J.659:267-274,2007 | 10.1086/511512 | null | astro-ph | null | We present a deep, 8$\degr$ diameter, 0.4 GHz radio image using a first time
combination of the NAIC Arecibo 305-m telescope in Puerto Rico, and the
wide-angle interferometer at the Dominion Radio Astrophysical Observatory at
Penticton, Canada. Our observations are centered on the Coma Cluster of
galaxies in the ``Great Wall'' of galaxies near the North Galactic Pole. The
complementary nature of these two instruments enables us to produce a
distortion-free image that is sensitive to radiation on scales from 8$\degr$
down to that of an individual galaxy halo at the 100 Mpc distance of the Great
Wall. Newly revealed patches of distributed radio ``glow'' are seen well above
the detection limit. One prominent such area coincides with groupings of radio
galaxies near the Coma cluster, and indicates intergalactic IGM magnetic fields
in the range 0.2 to 0.4 $\mu$G on scales of up to $\sim$ 4 Mpc. Other patches
of diffuse emission, not previously explored at these high latitudes on
arcminute scales, probably contain Galactic ``cirrus''. A striking
anticorrelation is found between low-level diffuse radio glow and some regions
of enhanced optical galaxy surface density, suggesting that cosmological Large
Scale Structure (LSS), normally defined by the baryonic (or dark) matter
density, is not {\it uniquely} traced by faint continuum radio glow. Rather,
intergalactic diffuse synchrotron radiation represents IGM magnetic and Cosmic
ray energy density, instead of matter density. The diffuse, arcminute-level
structures over a large region of sky are potentially important pathfinders to
CMB foreground radiation on high multipole scales.
| [
{
"version": "v1",
"created": "Wed, 25 Apr 2007 00:20:09 GMT"
}
] | 2010-11-05T00:00:00 | [
[
"Kronberg",
"P. P.",
""
],
[
"Kothes",
"R.",
""
],
[
"Salter",
"C. J.",
""
],
[
"Perillat",
"P.",
""
]
] |
0704.3289 | Boris Gutkin | Boris Gutkin | Dynamical "breaking" of time reversal symmetry and converse quantum
ergodicity | 10 pages, 5 figures | null | null | null | nlin.CD | null | It is a common assumption that quantum systems with time reversal invariance
and classically chaotic dynamics have energy spectra distributed according to
GOE-type of statistics. Here we present a class of systems which fail to follow
this rule. We show that for convex billiards of constant width with time
reversal symmetry and "almost" chaotic dynamics the energy level distribution
is of GUE-type. The effect is due to the lack of ergodicity in the "momentum"
part of the phase space and, as we argue, is generic in two dimensions.
Besides, we show that certain billiards of constant width in multiply connected
domains are of interest in relation to the quantum ergodicity problem. These
billiards are quantum ergodic, but not classically ergodic.
| [
{
"version": "v1",
"created": "Wed, 25 Apr 2007 00:54:54 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Gutkin",
"Boris",
""
]
] |
0704.3290 | Konstantin Mikhailov R. | A. Stavinskiy, K. Mikhailov, B. Erazmus, R. Lednicky | Residual correlations between decay products of $\pi^0\pi^0$ and
$p\Sigma^0$ systems | 10 pages, 5 figures | null | null | null | nucl-th hep-ph | null | Residual correlations between decay products due to a combination of both
correlations between parents at small relative velocities and small decay
momenta are discussed. Residual correlations between photons from pion decays
are considered as a new possible source of information on direct photon
fraction. Residual correlations in $p\gamma$ and $p\Lambda$ systems due to
$p\Sigma^0$ interaction in final state are predicted based on the $p\Sigma^0$
low energy scattering parameters deduced from the spin-flavour SU$_6$ model by
Fujiwara et al. including effective meson exchange potentials and explicit
flavour symmetry breaking to reproduce the properties of the two-nucleon system
and the low-energy hyperon-nucleon cross section data. The $p\gamma_{\Sigma^0}$
residual correlation is concentrated at $k^* \approx 70$ Mev/$c$ and its shape
and intensity appears to be sensitive to the scattering parameters and
space-time dimensions of the source. The $p\Lambda_{\Sigma^0}$ residual
correlation recovers the negative parent $p\Sigma^0$ correlation for $k^* > 70$
Mev/$c$. The neglect of this negative residual correlation would lead to the
underestimation of the parent $p\Lambda$ correlation effect and to an
overestimation of the source size.
| [
{
"version": "v1",
"created": "Wed, 25 Apr 2007 01:08:29 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Stavinskiy",
"A.",
""
],
[
"Mikhailov",
"K.",
""
],
[
"Erazmus",
"B.",
""
],
[
"Lednicky",
"R.",
""
]
] |
0704.3291 | Lukasz Fidkowski | Lukasz Fidkowski | Double Point Contact in the k=3 Read-Rezayi State | 7 pages, 3 figures | null | null | null | cond-mat.mes-hall cond-mat.str-el | null | We compute the dependence of the tunneling current in a double point contact
in the k=3 Read-Rezayi state (which is conjectured to describe an
incompressible quantum hall fluid at filling fraction nu=12/5) on voltage,
separation between the two contacts, and temperature. Using the tunneling
hamiltonian of cond-mat/0607431, we show that the effect of quasiholes in the
bulk region between the two contacts is simply an overall constant multiplying
the interference term. This is the same effect as found for the differential
conductivity in cond-mat/0601242; the difference is that we do an actual edge
theory calculation and compute the full current-voltage curve at weak
tunneling.
| [
{
"version": "v1",
"created": "Wed, 25 Apr 2007 01:17:30 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Fidkowski",
"Lukasz",
""
]
] |
0704.3292 | Zhu Han | Zhu Han and H. Vincent Poor | Coalition Games with Cooperative Transmission: A Cure for the Curse of
Boundary Nodes in Selfish Packet-Forwarding Wireless Networks | null | in the Proceedings of the 5th International Symposium on Modeling
and Optimization in Mobile Ad Hoc and Wireless Networks, WiOpt07, Limassol,
Cyprus, April 16-20, 2007 | null | null | cs.IT math.IT | null | In wireless packet-forwarding networks with selfish nodes, applications of a
repeated game can induce the nodes to forward each others' packets, so that the
network performance can be improved. However, the nodes on the boundary of such
networks cannot benefit from this strategy, as the other nodes do not depend on
them. This problem is sometimes known as the curse of the boundary nodes. To
overcome this problem, an approach based on coalition games is proposed, in
which the boundary nodes can use cooperative transmission to help the backbone
nodes in the middle of the network. In return, the backbone nodes are willing
to forward the boundary nodes' packets. The stability of the coalitions is
studied using the concept of a core. Then two types of fairness, namely, the
min-max fairness using nucleolus and the average fairness using the Shapley
function are investigated. Finally, a protocol is designed using both repeated
games and coalition games. Simulation results show how boundary nodes and
backbone nodes form coalitions together according to different fairness
criteria. The proposed protocol can improve the network connectivity by about
50%, compared with pure repeated game schemes.
| [
{
"version": "v1",
"created": "Wed, 25 Apr 2007 15:37:22 GMT"
},
{
"version": "v2",
"created": "Wed, 25 Apr 2007 21:15:48 GMT"
}
] | 2007-07-13T00:00:00 | [
[
"Han",
"Zhu",
""
],
[
"Poor",
"H. Vincent",
""
]
] |
0704.3293 | Andrea Montanari | Antoine Gerschenfeld and Andrea Montanari | Reconstruction for models on random graphs | 16 pages | null | null | null | math.PR cond-mat.stat-mech math.CO | null | Consider a collection of random variables attached to the vertices of a
graph. The reconstruction problem requires to estimate one of them given `far
away' observations. Several theoretical results (and simple algorithms) are
available when their joint probability distribution is Markov with respect to a
tree. In this paper we consider the case of sequences of random graphs that
converge locally to trees. In particular, we develop a sufficient condition for
the tree and graph reconstruction problem to coincide. We apply such condition
to colorings of random graphs.
Further, we characterize the behavior of Ising models on such graphs, both
with attractive and random interactions (respectively, `ferromagnetic' and
`spin glass').
| [
{
"version": "v1",
"created": "Wed, 25 Apr 2007 01:35:38 GMT"
},
{
"version": "v2",
"created": "Mon, 10 Sep 2007 05:14:58 GMT"
}
] | 2007-09-10T00:00:00 | [
[
"Gerschenfeld",
"Antoine",
""
],
[
"Montanari",
"Andrea",
""
]
] |
0704.3294 | Jonathan E. Grindlay | Jonathan E. Grindlay | AGN Variability Surveys: DASCH from BATSS to EXIST | 4 pages, 3 figures, Conference proceedings to appear in "The Central
Engine of Active Galactic Nuclei", eds. L. C. Ho and J.-M. Wang (San
Francisco: ASP) | null | null | null | astro-ph | null | Active galactic nuclei (AGN) are variable on a wide range of timescales,
though relatively few systematic variability surveys have been conducted.
Previous broad-band (both spectral and temporal) variability surveys of AGN are
limited in their temporal and spectral bandwidth, despite their promise for
probing the central engine and black hole mass. We outline optimal properties
for variability studies and provide a brief summary of three new variability
surveys, two (BATSS and DASCH) about to begin and the third (EXIST) possible
within the next decade, which will open new windows on the physics and
fundamental properties of AGN.
| [
{
"version": "v1",
"created": "Wed, 25 Apr 2007 01:53:25 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Grindlay",
"Jonathan E.",
""
]
] |
0704.3295 | Monica Guica | Monica Guica, Andrew Strominger | Cargese lectures on string theory with eight supercharges | 30 pp, 7 figures, based on lecture notes by A. Strominger at the 2006
Cargese summer school | Nucl.Phys.Proc.Suppl.171:39-68,2007 | 10.1016/j.nuclphysbps.2007.06.007 | null | hep-th | null | These lectures give an introduction to the interrelated topics of Calabi-Yau
compactification of the type II string, black hole attractors, the all-orders
entropy formula, the dual (0,4) CFT, topological strings and the OSV
conjecture. Based on notes by MG of lectures by AS at the 2006 Cargese summer
school.
| [
{
"version": "v1",
"created": "Wed, 25 Apr 2007 02:01:32 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Guica",
"Monica",
""
],
[
"Strominger",
"Andrew",
""
]
] |
0704.3296 | Anton Lipovka | J. Campos, A. Lipovka, J. Saucedo | Formation of C- by radiative association | 3 pages, 1 figure | null | null | null | astro-ph | null | In the present paper the problem of the radiative association of atoms of
carbon C with electrons $e^{-}$ for kinetic temperatures $T_{c}$ of $100 <
T_{c} < 3000$ K is considered. The calculation of the rate rate constant of the
radiative associations is made with principle of detailed balance. It is shown
that the rate has correct behavior (it increase with the temperature) and its
behavior is look-like that for the $H^{-}$ formation rate coefficient, which
also increase with the temperature.
| [
{
"version": "v1",
"created": "Wed, 25 Apr 2007 02:01:45 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Campos",
"J.",
""
],
[
"Lipovka",
"A.",
""
],
[
"Saucedo",
"J.",
""
]
] |
0704.3297 | Antia Lamas-Linares | Antia Lamas-Linares and Christian Kurtsiefer | Breaking a quantum key distribution system through a timing side channel | 6 pages, 4 figures. Added additional references and extended
analysis. Identical to published version | Opt. Express 15, 9388 (2007) | 10.1364/OE.15.009388 | null | quant-ph | null | The security of quantum key distribution relies on the validity of quantum
mechanics as a description of nature and on the non-existence of leaky degrees
of freedom in the practical implementations. We experimentally demonstrate how,
in some implementations, timing information revealed during public discussion
between the communicating parties can be used by an eavesdropper to
undetectably access a significant portion of the ``secret'' key.
| [
{
"version": "v1",
"created": "Wed, 25 Apr 2007 02:07:36 GMT"
},
{
"version": "v2",
"created": "Tue, 17 Jul 2007 09:45:55 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Lamas-Linares",
"Antia",
""
],
[
"Kurtsiefer",
"Christian",
""
]
] |
0704.3298 | Abdul Rahman | Abdul Rahman | A Perverse Sheaf Approach Toward a Cohomology Theory for String Theory | Added section 5 (an example) | null | null | null | math.AT hep-th math-ph math.MP | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We present the construction and properties of a self-dual perverse sheaf S_0
whose cohomology fulfills some of the requirements of String theory as outlined
by T. Hubsch in hep-th/9612075. The construction of this S_0 utilizes
techniques that follow from MacPherson-Vilonen (Inv. Math. vol. 84, pp.
403-435, 1986). Finally, we will discuss its properties as they relate to
String theory.
| [
{
"version": "v1",
"created": "Wed, 25 Apr 2007 12:36:54 GMT"
},
{
"version": "v2",
"created": "Wed, 25 Apr 2007 22:10:58 GMT"
},
{
"version": "v3",
"created": "Mon, 30 Apr 2007 12:07:35 GMT"
},
{
"version": "v4",
"created": "Mon, 27 Aug 2007 01:45:58 GMT"
},
{
"version": "v5",
"created": "Wed, 20 May 2009 21:06:14 GMT"
}
] | 2009-05-21T00:00:00 | [
[
"Rahman",
"Abdul",
""
]
] |
0704.3299 | Kunihiko Terasaki | Kunihiko Terasaki | D_{s0}^+(2317) as an Iso-triplet Four-quark Meson and Production of Its
Neutral and Doubly Charged Partners | 6 pages, 3 figures, RevTeX | Prog.Theor.Phys.Suppl.168:211-218,2007 | 10.1143/PTPS.168.211 | YITP-07-22, KANAZAWA-07-02 | hep-ph hep-ex nucl-th | null | By studying the decays D_{s0}^+(2317) --> D_s^+ pi^0 and D_s^{*+} gamma, It
is shown that its assignment to the I_3=0 component of iso-triplet scalar
four-quark mesons is favored. Productions of its neutral and doubly charged
partners are also studied. As the result, it is concluded that they could be
observed in B decays. Their iso-singlet partner might have been observed in the
radiative channels of B decays by the BELLE Collaboration.
| [
{
"version": "v1",
"created": "Wed, 25 Apr 2007 03:01:02 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Terasaki",
"Kunihiko",
""
]
] |
0704.3300 | Kohkichi Konno | Kohkichi Konno, Munehiro Nishida, Satoshi Tanda, Noriyuki Hatakenaka | The effect of dissipation on quantum transmission resonance | 8 pages, 5 figures, Accepted for publication in Physics Letters A | Physics Letters A 368 (2007) 442-449 | 10.1016/j.physleta.2007.04.055 | null | quant-ph | null | Quantum transmissions of a free particle passing through a rectangular
potential barrier with dissipation are studied using a path decomposition
technique. Dissipative processes strongly suppress the transmission probability
at resonance just above the barrier resulting in an unexpected reduction of the
mean traversal time through the potential barrier.
| [
{
"version": "v1",
"created": "Wed, 25 Apr 2007 03:03:22 GMT"
}
] | 2007-08-27T00:00:00 | [
[
"Konno",
"Kohkichi",
""
],
[
"Nishida",
"Munehiro",
""
],
[
"Tanda",
"Satoshi",
""
],
[
"Hatakenaka",
"Noriyuki",
""
]
] |
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