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sequence |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
0704.2601 | Boris H\"au{\ss}ler | Boris H\"au{\ss}ler, Daniel H. McIntosh, Marco Barden, Eric F. Bell,
Hans-Walter Rix, Andrea Borch, Steven V. W. Beckwith, John A. R. Caldwell,
Catherine Heymans, Knud Jahnke, Shardha Jogee, Sergey E. Koposov, Klaus
Meisenheimer, Sebastian F. S\'anchez, Rachel S. Somerville, Lutz Wisotzki,
Christian Wolf | GEMS: Galaxy fitting catalogues and testing parametric galaxy fitting
codes | Accepted for publication in ApJS October 2007, v172n2; 25 pages, 16
Figures, 9 Tables; for hi-resolution version, see
http://www.mpia.de/homes/bhaeussl/galaxy_fitting.pdf. For results, catalogues
and files for code-testing, see http://www.mpia.de/GEMS/fitting_paper.html | null | 10.1086/518836 | null | astro-ph | null | In the context of measuring structure and morphology of intermediate redshift
galaxies with recent HST/ACS surveys, we tune, test, and compare two widely
used fitting codes (GALFIT and GIM2D) for fitting single-component Sersic
models to the light profiles of both simulated and real galaxy data. We find
that fitting accuracy depends sensitively on galaxy profile shape. Exponential
disks are well fit with Sersic models and have small measurement errors,
whereas fits to de Vaucouleurs profiles show larger uncertainties owing to the
large amount of light at large radii. We find that both codes provide reliable
fits and little systematic error, when the effective surface brightness is
above that of the sky. Moreover, both codes return errors that significantly
underestimate the true fitting uncertainties, which are best estimated with
simulations. We find that GIM2D suffers significant systematic errors for
spheroids with close companions owing to the difficulty of effectively masking
out neighboring galaxy light; there appears to be no work around to this
important systematic in GIM2D's current implementation. While this crowding
error affects only a small fraction of galaxies in GEMS, it must be accounted
for in the analysis of deeper cosmological images or of more crowded fields
with GIM2D. In contrast, GALFIT results are robust to the presence of neighbors
because it can simultaneously fit the profiles of multiple companions thereby
deblending their effect on the fit to the galaxy of interest. We find GALFIT's
robustness to nearby companions and factor of >~20 faster runtime speed are
important advantages over GIM2D for analyzing large HST/ACS datasets. Finally
we include our final catalog of fit results for all 41,495 objects detected in
GEMS.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 20:00:55 GMT"
},
{
"version": "v2",
"created": "Mon, 7 May 2007 13:36:24 GMT"
}
] | 2016-08-14T00:00:00 | [
[
"Häußler",
"Boris",
""
],
[
"McIntosh",
"Daniel H.",
""
],
[
"Barden",
"Marco",
""
],
[
"Bell",
"Eric F.",
""
],
[
"Rix",
"Hans-Walter",
""
],
[
"Borch",
"Andrea",
""
],
[
"Beckwith",
"Steven V. W.",
""
],
[
"Caldwell",
"John A. R.",
""
],
[
"Heymans",
"Catherine",
""
],
[
"Jahnke",
"Knud",
""
],
[
"Jogee",
"Shardha",
""
],
[
"Koposov",
"Sergey E.",
""
],
[
"Meisenheimer",
"Klaus",
""
],
[
"Sánchez",
"Sebastian F.",
""
],
[
"Somerville",
"Rachel S.",
""
],
[
"Wisotzki",
"Lutz",
""
],
[
"Wolf",
"Christian",
""
]
] |
0704.2602 | Mohamad Ali Jafarizadeh | M. A. Jafarizadeh, R. Sufiani | Investigation of continuous-time quantum walks via spectral analysis and
Laplace transform | 28 pages | null | null | null | quant-ph | null | Continuous-time quantum walk (CTQW) on a given graph is investigated by using
the techniques of the spectral analysis and inverse Laplace transform of the
Stieltjes function (Stieltjes transform of the spectral distribution)
associated with the graph. It is shown that, the probability amplitude of
observing the CTQW at a given site at time $t$ is related to the inverse
Laplace transformation of the Stieltjes function, namely, one can calculate the
probability amplitudes only by taking the inverse laplace transform of the
function $iG_{\mu}(is)$, where $G_{\mu}(x)$ is the Stieltjes function of the
graph. The preference of this procedure is that, there is no any need to know
the spectrum of the graph
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 20:01:11 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Jafarizadeh",
"M. A.",
""
],
[
"Sufiani",
"R.",
""
]
] |
0704.2603 | Tom Bell | T. A. Bell, S. Viti, D. A. Williams | Molecular line intensities as measures of cloud masses - II. Conversion
factors for specific galaxy types | 14 pages, 11 figures, accepted for publication in MNRAS | Mon.Not.Roy.Astron.Soc.378:983-994,2007 | 10.1111/j.1365-2966.2007.11830.x | null | astro-ph | null | We present theoretically-established values of the CO-to-H2 and C-to-H2
conversion factors that may be used to estimate the gas masses of external
galaxies. We consider four distinct galaxy types, represented by M51, NGC 6946,
M82 and SMC N27. The physical parameters that best represent the conditions
within the molecular clouds in each of the galaxy types are estimated using a
chi^2 analysis of several observed atomic fine structure and CO rotational
lines. This analysis is explored over a wide range of density, radiation field,
extinction, and other relevant parameters. Using these estimated physical
conditions in methods that we have previously established, CO-to-H2 conversion
factors are then computed for CO transitions up to J=9-8. For the conventional
CO(1-0) transition, the computed conversion factor varies significantly below
and above the canonical value for the Milky Way in the four galaxy types
considered. Since atomic carbon emission is now frequently used as a probe of
external galaxies, we also present, for the first time, the C-to-H2 conversion
factor for this emission in the four galaxy types considered.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 23:08:38 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"Bell",
"T. A.",
""
],
[
"Viti",
"S.",
""
],
[
"Williams",
"D. A.",
""
]
] |
0704.2604 | Elena D'Onghia | E. D'Onghia (1), A.V. Maccio'(2), G. Lake (1), J. Stadel (1), B. Moore
(1)((1) University of Zurich, (2) MPIA Heidelberg) | Universal Substructure Distributions in LCDM halos: Can we find a Fossil
Group? | Submitted for publication in MNRAS, 8 pages, 8 figures | null | null | null | astro-ph | null | We use large cosmological N-body simulations to study the subhalo population
in galaxy group sized halos. In particular, we look for fossil group candidates
with typical masses ~10-25% of Virgo cluster but with an order of magnitude
less substructure. We examine recent claims that the earliest systems to form
are deficient enough in substructure to explain the luminosity function found
in fossil groups. Although our simulations show a correlation between the halo
formation time and the number of subhalos, the maximum suppression of subhalos
is a factor of 2-2.5, whereas a factor of 6 is required to match fossil groups
and galaxies. While the number of subhalos depends weakly on the formation
time, the slope of the halo substructure velocity function does not. The
satellite population within Cold Dark Matter (CDM) halos is self-similar at
scales between galaxies and galaxy clusters regardless of mass, whereas current
observations show a break in self-similarity at a mass scale corresponding to
group of galaxies.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 20:02:12 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"D'Onghia",
"E.",
"",
"University of Zurich"
],
[
"Maccio'",
"A. V.",
"",
"MPIA Heidelberg"
],
[
"Lake",
"G.",
"",
"University of Zurich"
],
[
"Stadel",
"J.",
"",
"University of Zurich"
],
[
"Moore",
"B.",
"",
"University of Zurich"
]
] |
0704.2605 | Brent Bryan | Brent Bryan, Jeff Schneider, Christopher J. Miller, Robert C. Nichol,
Christopher Genovese, Larry Wasserman | Mapping the Cosmological Confidence Ball Surface | 41 pages, 12 figures. To appear in ApJ | Astrophys.J.665:25-41,2007 | 10.1086/518999 | null | astro-ph | null | We present a new technique to compute simultaneously valid confidence
intervals for a set of model parameters. We apply our method to the Wilkinson
Microwave Anisotropy Probe's (WMAP) Cosmic Microwave Background (CMB) data,
exploring a seven dimensional space (tau, Omega_DE, Omega_M, omega_DM, omega_B,
f_nu, n_s). We find two distinct regions-of-interest: the standard Concordance
Model, and a region with large values of omega_DM, omega_B and H_0. This second
peak in parameter space can be rejected by applying a constraint (or a prior)
on the allowable values of the Hubble constant. Our new technique uses a
non-parametric fit to the data, along with a frequentist approach and a smart
search algorithm to map out a statistical confidence surface. The result is a
confidence ``ball'': a set of parameter values that contains the true value
with probability at least 1-alpha. Our algorithm performs a role similar to the
often used Markov Chain Monte Carlo (MCMC), which samples from the posterior
probability function in order to provide Bayesian credible intervals on the
parameters. While the MCMC approach samples densely around a peak in the
posterior, our new technique allows cosmologists to perform efficient analyses
around any regions of interest: e.g., the peak itself, or, possibly more
importantly, the 1-alpha confidence surface.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 20:10:06 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"Bryan",
"Brent",
""
],
[
"Schneider",
"Jeff",
""
],
[
"Miller",
"Christopher J.",
""
],
[
"Nichol",
"Robert C.",
""
],
[
"Genovese",
"Christopher",
""
],
[
"Wasserman",
"Larry",
""
]
] |
0704.2606 | Elisabetta Majerotto | Ruth Lazkoz (Basque U., Bilbao) and Elisabetta Majerotto (ICG,
Portsmouth) | Cosmological constraints combining H(z), CMB shift and SNIa
observational data | 17 pages, 11 figures; improved discussion, new figures, updated to
match published version | JCAP 0707:015,2007 | 10.1088/1475-7516/2007/07/015 | null | astro-ph | null | Recently H(z) data obtained from differential ages of galaxies have been
proposed as a new geometrical probe of dark energy. In this paper we use those
data, combined with other background tests (CMB shift and SNIa data), to
constrain a set of general relativistic dark energy models together with some
other models motivated by extra dimensions. Our analysis rests mostly on
Bayesian statistics, and we conclude that LCDM is at least substantially
favoured, and that braneworld models are less favoured than general
relativistic ones.
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 17:00:39 GMT"
},
{
"version": "v2",
"created": "Fri, 27 Jul 2007 16:21:36 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Lazkoz",
"Ruth",
"",
"Basque U., Bilbao"
],
[
"Majerotto",
"Elisabetta",
"",
"ICG,\n Portsmouth"
]
] |
0704.2607 | Eric Hallman | Eric J. Hallman (1), Brian W. O'Shea (2), Jack O. Burns (1), Michael
L. Norman (3), Robert Harkness (4), Rick Wagner (3) ((1) University of
Colorado, (2) Los Alamos National Laboratory, (3) University of
California-San Diego, (4) San Diego Supercomputing Center) | The Santa Fe Light Cone Simulation Project: I. Confusion and the WHIM in
Upcoming Sunyaev-Zel'dovich Effect Surveys | 14 pages, 13 figures, version accepted to ApJ. Major revisions made | null | 10.1086/522912 | null | astro-ph | null | We present the first results from a new generation of simulated large sky
coverage (~100 square degrees) Sunyaev-Zeldovich effect (SZE) cluster surveys
using the cosmological adaptive mesh refinement N-body/hydro code Enzo. We have
simulated a very large (512^3h^{-3}Mpc^3) volume with unprecedented dynamic
range. We have generated simulated light cones to match the resolution and
sensitivity of current and future SZE instruments. Unlike many previous studies
of this type, our simulation includes unbound gas, where an appreciable
fraction of the baryons in the universe reside.
We have found that cluster line-of-sight overlap may be a significant issue
in upcoming single-dish SZE surveys. Smaller beam surveys (~1 arcmin) have more
than one massive cluster within a beam diameter 5-10% of the time, and a larger
beam experiment like Planck has multiple clusters per beam 60% of the time. We
explore the contribution of unresolved halos and unbound gas to the SZE
signature at the maximum decrement. We find that there is a contribution from
gas outside clusters of ~16% per object on average for upcoming surveys. This
adds both bias and scatter to the deduced value of the integrated SZE, adding
difficulty in accurately calibrating a cluster Y-M relationship.
Finally, we find that in images where objects with M > 5x10^{13} M_{\odot}
have had their SZE signatures removed, roughly a third of the total SZE flux
still remains. This gas exists at least partially in the Warm Hot Intergalactic
Medium (WHIM), and will possibly be detectable with the upcoming generation of
SZE surveys.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 20:21:10 GMT"
},
{
"version": "v2",
"created": "Fri, 27 Apr 2007 15:22:39 GMT"
},
{
"version": "v3",
"created": "Wed, 29 Aug 2007 21:38:54 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Hallman",
"Eric J.",
""
],
[
"O'Shea",
"Brian W.",
""
],
[
"Burns",
"Jack O.",
""
],
[
"Norman",
"Michael L.",
""
],
[
"Harkness",
"Robert",
""
],
[
"Wagner",
"Rick",
""
]
] |
0704.2608 | Alexander Tchekhovskoy | Alexander Tchekhovskoy, Jonathan C. McKinney, Ramesh Narayan
(Harvard-CfA) | WHAM: A WENO-based general relativistic numerical scheme I:
Hydrodynamics | 33 pages, 22 figures, accepted to MNRAS, for a version with high
quality figures see
http://www.cfa.harvard.edu/~atchekho/research/wham1hires.pdf | Mon.Not.Roy.Astron.Soc.379:469-497,2007 | 10.1111/j.1365-2966.2007.11876.x | null | astro-ph | null | Active galactic nuclei, x-ray binaries, pulsars, and gamma-ray bursts are all
believed to be powered by compact objects surrounded by relativistic plasma
flows driving phenomena such as accretion, winds, and jets. These flows are
often accurately modelled by the relativistic magnetohydrodynamics (MHD)
approximation. Time-dependent numerical MHD simulations have proven to be
especially insightful, but one regime that remains difficult to simulate is
when the energy scales (kinetic, thermal, magnetic) within the plasma become
disparate. We develop a numerical scheme that significantly improves the
accuracy and robustness of the solution in this regime. We use a modified form
of the WENO method to construct a finite-volume general relativistic
hydrodynamics code called WHAM that converges at fifth order. We avoid (1)
field-by-field decomposition by adaptively reducing down to 2-point stencils
near discontinuities for a more accurate treatment of shocks, and (2) excessive
reduction to low order stencils, as in the standard WENO formalism, by
maintaining high order accuracy in smooth monotonic flows. Our scheme performs
the proper surface integral of the fluxes, converts cell averaged conserved
quantities to point conserved quantities before performing the reconstruction
step, and correctly averages all source terms. We demonstrate that the scheme
is robust in strong shocks, very accurate in smooth flows, and maintains
accuracy even when the energy scales in the flow are highly disparate.
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 05:00:04 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"Tchekhovskoy",
"Alexander",
"",
"Harvard-CfA"
],
[
"McKinney",
"Jonathan C.",
"",
"Harvard-CfA"
],
[
"Narayan",
"Ramesh",
"",
"Harvard-CfA"
]
] |
0704.2609 | Shamil Shakirov | V.Dolotin, A.Morozov and Sh.Shakirov | A-infinity structure on simplicial complexes | final version. 29 pages | null | 10.1007/s11232-008-0093-9 | ITEP/TH-13/07 | math.GT cs.DM hep-th | null | A discrete (finite-difference) analogue of differential forms is considered,
defined on simplicial complexes, including triangulations of continuous
manifolds. Various operations are explicitly defined on these forms, including
exterior derivative and exterior product. The latter one is non-associative.
Instead, as anticipated, it is a part of non-trivial A-infinity structure,
involving a chain of poly-linear operations, constrained by nilpotency
relation: (d + \wedge + m + ...)^n = 0 with n=2.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 20:48:51 GMT"
},
{
"version": "v2",
"created": "Sun, 22 Apr 2007 19:42:39 GMT"
},
{
"version": "v3",
"created": "Thu, 17 May 2007 17:29:02 GMT"
},
{
"version": "v4",
"created": "Sat, 23 Jun 2007 02:42:15 GMT"
},
{
"version": "v5",
"created": "Fri, 19 Oct 2007 16:52:46 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Dolotin",
"V.",
""
],
[
"Morozov",
"A.",
""
],
[
"Shakirov",
"Sh.",
""
]
] |
0704.2610 | Yuri Genenko | Yuri A. Genenko and Doru C. Lupascu | Drift of charged defects in local fields as aging mechanism in
ferroelectrics | 24 pages, 12 figures, accepted to Physical Review B | Physical Review B 75, 184107 (2007) | 10.1103/PhysRevB.75.184107 | null | cond-mat.mtrl-sci | null | Point defect migration is considered as a mechanism for aging in
ferroelectrics. Numerical results are given for the coupled problems of point
defect migration and electrostatic energy relaxation in a 2D domain
configuration. The peak values of the clamping pressure at domain walls are in
the range of $10^6$ Pa, which corresponds to macroscopically observed coercive
stresses in perovskite ferroelectrics. The effect is compared to mechanisms
involving orientational reordering of defect dipoles in the bulk of domains.
Domain clamping is significantly stronger in the drift mechanism than in the
orientational picture for the same material parameters.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 20:37:20 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Genenko",
"Yuri A.",
""
],
[
"Lupascu",
"Doru C.",
""
]
] |
0704.2611 | Boris N. Narozhny | B.N. Narozhny | Coulomb drag as a measure of trigonal warping in doped graphene | 4 pages, 1 figure | Phys. Rev. B 76, 153409 (2007) | 10.1103/PhysRevB.76.153409 | null | cond-mat.mes-hall | null | I suggest to use the effect of Coulomb drag between two closely positioned
graphite monolayers (graphene sheets) for experimental measurement of the
strength of weak non-linearities of the spectrum in graphene. I consider
trigonal warping as a representative mechanism responsible for the drag effect.
Since graphene is relatively defect-free, I evaluate the drag conductivity in
the ballistic regime and find that it is proportional to the fourth power of
the warping strength.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 22:47:51 GMT"
}
] | 2016-01-11T00:00:00 | [
[
"Narozhny",
"B. N.",
""
]
] |
0704.2612 | Nicolas Yunes | Nicolas Yunes, Carlos F. Sopuerta, Louis J. Rubbo and Kelly
Holley-Bockelmann | Relativistic Effects in Extreme Mass Ratio Gravitational Wave Bursts | 13 pages, 8 figures, 2 tables. Replaced with version accepted for
publication in the Ap. J | Astrophys.J.675:604-613,2008 | 10.1086/525839 | IGPG-07/4-3 | astro-ph gr-qc | null | Extreme mass ratio bursts (EMRBs) have been proposed as a possible source for
future space-borne gravitational wave detectors, such as the Laser
Interferometer Space Antenna (LISA). These events are characterized by
long-period, nearly-radial orbits of compact objects around a central massive
black hole. The gravitational radiation emitted during such events consists of
a short burst, corresponding to periapse passage, followed by a longer, silent
interval. In this paper we investigate the impact of including relativistic
corrections to the description of the compact object's trajectory via a
geodesic treatment, as well as including higher-order multipole corrections in
the waveform calculation. The degree to which the relativistic corrections are
important depends on the EMRB's orbital parameters. We find that relativistic
EMRBs (v_{max}}/c > 0.25) are not rare and actually account for approximately
half of the events in our astrophysical model. The relativistic corrections
tend to significantly change the waveform amplitude and phase relative to a
Newtonian description, although some of this dephasing could be mimicked by
parameter errors. The dephasing over several bursts could be of particular
importance not only to gravitational wave detection, but also to parameter
estimation, since it is highly correlated to the spin of the massive black
hole. Consequently, we postulate that if a relativistic EMRB is detected, such
dephasing might be used to probe the relativistic character of the massive
black hole and obtain information about its spin.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 20:50:42 GMT"
},
{
"version": "v2",
"created": "Thu, 8 Nov 2007 21:20:09 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Yunes",
"Nicolas",
""
],
[
"Sopuerta",
"Carlos F.",
""
],
[
"Rubbo",
"Louis J.",
""
],
[
"Holley-Bockelmann",
"Kelly",
""
]
] |
0704.2613 | Alessandro Tomasiello | Alessandro Tomasiello | Reformulating Supersymmetry with a Generalized Dolbeault Operator | 30 pages, no figures. v2: minor corrections | JHEP0802:010,2008 | 10.1088/1126-6708/2008/02/010 | SU-ITP-07/06 | hep-th | null | The conditions for N=1 supersymmetry in type II supergravity have been
previously reformulated in terms of generalized complex geometry. We improve
that reformulation so as to completely eliminate the remaining explicit
dependence on the metric. Doing so involves a natural generalization of the
Dolbeault operator. As an application, we present some general arguments about
supersymmetric moduli. In particular, a subset of them are then classified by a
certain cohomology. We also argue that the Dolbeault reformulation should make
it easier to find existence theorems for the N=1 equations.
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 03:13:35 GMT"
},
{
"version": "v2",
"created": "Mon, 24 Dec 2007 17:09:31 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Tomasiello",
"Alessandro",
""
]
] |
0704.2614 | Andrew Walsh | Andrew G. Walsh, A. Nickolas Vamivakas, Yan Yin, Stephen B. Cronin, M.
Selim Unlu, Bennett B. Goldberg, and Anna K. Swan | Screening of Excitons in Single, Suspended Carbon Nanotubes | Accepted to Nano Letters 5 Pages, 3 Figures, 2 Tables | null | 10.1021/nl070193p | null | cond-mat.other | null | Resonant Raman spectroscopy of single carbon nanotubes suspended across
trenches displays red shifts of up to 30 meV of the electronic transition
energies as a function of the surrounding dielectric environment. We develop a
simple scaling relationship between the exciton binding energy and the external
dielectric function and thus quantify the effect of screening. Our results
imply that the underlying particle interaction energies change by hundreds of
meV.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 20:46:15 GMT"
}
] | 2015-05-13T00:00:00 | [
[
"Walsh",
"Andrew G.",
""
],
[
"Vamivakas",
"A. Nickolas",
""
],
[
"Yin",
"Yan",
""
],
[
"Cronin",
"Stephen B.",
""
],
[
"Unlu",
"M. Selim",
""
],
[
"Goldberg",
"Bennett B.",
""
],
[
"Swan",
"Anna K.",
""
]
] |
0704.2615 | Andrei Teleman | Christian Okonek, Andrei Teleman | Cohomotopy invariants and the universal cohomotopy invariant jump
formula | LaTeX, 51 pages. v2: References added. More details in the
introduction. v3: New comments about the functorial properties of the groups
to which the new invariants belong (and about the functoriality of the
Bauer-Furuta classes) have been added. To appear in Journal of Mathematical
Sciences the University of Tokyo | null | null | null | math.GT math.AT | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Starting from ideas of Furuta, we develop a general formalism for the
construction of cohomotopy invariants associated with a certain class of
$S^1$-equivariant non-linear maps between Hilbert bundles. Applied to the
Seiberg-Witten map, this formalism yields a new class of cohomotopy
Seiberg-Witten invariants which have clear functorial properties with respect
to diffeomorphisms of 4-manifolds. Our invariants and the Bauer-Furuta classes
are directly comparable for 4-manifolds with $b_1=0$; they are equivalent when
$b_1=0$ and $b_+>1$, but are finer in the case $b_1=0$, $b_+=1$ (they detect
the wall-crossing phenomena).
We study fundamental properties of the new invariants in a very general
framework. In particular we prove a universal cohomotopy invariant jump formula
and a multiplicative property. The formalism applies to other gauge theoretical
problems, e.g. to the theory of gauge theoretical (Hamiltonian) Gromov-Witten
invariants.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 21:18:04 GMT"
},
{
"version": "v2",
"created": "Sat, 5 May 2007 16:45:28 GMT"
},
{
"version": "v3",
"created": "Fri, 18 May 2007 18:48:18 GMT"
},
{
"version": "v4",
"created": "Tue, 14 Oct 2008 17:04:32 GMT"
}
] | 2008-10-14T00:00:00 | [
[
"Okonek",
"Christian",
""
],
[
"Teleman",
"Andrei",
""
]
] |
0704.2616 | Rudolph C. Hwa | Charles B. Chiu and Rudolph C. Hwa | Particles Associated with Omega Produced at Intermediate p_T | 16 pages + 2 figures | Phys.Rev.C76:024904,2007 | 10.1103/PhysRevC.76.024904 | null | nucl-th | null | The dual observation of the Omega production in central Au+Au collisions
having both an exponential p_T distribution and also associated particles above
the background has been referred to as the Omega puzzle. We give a quantitative
description of how that puzzle can be understood in terms of phantom jets,
where only ridges without peaks are produced to give rise to both the Omega
trigger and its associated particles. In the framework of recombination of
thermal partons we are able to reproduce both the \Delta\phi distribution and
the trigger-momentum dependence of the yield of the associated particles. We
make predictions on other observables that can be checked by further analyses
of the data.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 21:18:41 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Chiu",
"Charles B.",
""
],
[
"Hwa",
"Rudolph C.",
""
]
] |
0704.2617 | Aldo Procacci | Roberto Fernandez, Aldo Procacci | Regions without complex zeros for chromatic polynomials on graphs with
bounded degree | 14 pages, to appear in Combinatorics, Probability and Computing | null | null | null | math-ph math.CO math.MP | null | We prove that the chromatic polynomial $P_\mathbb{G}(q)$ of a finite graph
$\mathbb{G}$ of maximal degree $\D$ is free of zeros for $\card q\ge C^*(\D)$
with $$ C^*(\D) = \min_{0<x<2^{1\over \D}-1} {(1+x)^{\D-1}\over x [2-(1+x)^\D]}
$$ This improves results by Sokal (2001) and Borgs (2005). Furthermore, we
present a strengthening of this condition for graphs with no triangle-free
vertices.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 21:25:09 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Fernandez",
"Roberto",
""
],
[
"Procacci",
"Aldo",
""
]
] |
0704.2618 | Ross Young | R. D. Young, R. D. Carlini, A. W. Thomas, J. Roche | Testing the Standard Model by precision measurement of the weak charges
of quarks | 4 pages, 3 figures; v2: further details on extraction of electroweak
parameters, new figure | Phys.Rev.Lett.99:122003,2007 | 10.1103/PhysRevLett.99.122003 | JLAB-THY-07-636, ADP-07-04-T644 | hep-ph | null | In a global analysis of the latest parity-violating electron scattering
measurements on nuclear targets, we demonstrate a significant improvement in
the experimental knowledge of the weak neutral-current lepton-quark
interactions at low energy. The precision of this new result, combined with
earlier atomic parity-violation measurements, places tight constraints on the
size of possible contributions from physics beyond the Standard Model.
Consequently, this result improves the lower-bound on the scale of relevant new
physics to ~1 TeV.
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 17:55:34 GMT"
},
{
"version": "v2",
"created": "Fri, 8 Jun 2007 19:24:55 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Young",
"R. D.",
""
],
[
"Carlini",
"R. D.",
""
],
[
"Thomas",
"A. W.",
""
],
[
"Roche",
"J.",
""
]
] |
0704.2619 | Gabriel T\'ellez | Diego Luis Gonzalez and Gabriel Tellez (Universidad de los Andes,
Bogota, Colombia) | Statistical Behavior Of Domain Systems | v2: minor changes | Phys. Rev E 76, 011126 (2007) | 10.1103/PhysRevE.76.011126 | null | cond-mat.stat-mech | null | We study the statistical behavior of two out of equilibrium systems. The
first one is a quasi one-dimensional gas with two species of particles under
the action of an external field which drives each species in opposite
directions. The second one is a one-dimensional spin system with nearest
neighbor interactions also under the influence of an external driving force.
Both systems show a dynamical scaling with domain formation. The statistical
behavior of these domains is compared with models based on the coalescing
random walk and the interacting random walk. We find that the scaling domain
size distribution of the gas and the spin systems is well fitted by the Wigner
surmise, which lead us to explore a possible connection between these systems
and the circular orthogonal ensemble of random matrices. However, the study of
the correlation function of the domain edges, show that the statistical
behavior of the domains in both gas and spin systems, is not completely well
described by circular orthogonal ensemble, nor it is by other models proposed
such as the coalescing random walk and the interacting random walk.
Nevertheless, we find that a simple model of independent intervals describe
more closely the statistical behavior of the domains formed in these systems.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 21:54:58 GMT"
},
{
"version": "v2",
"created": "Fri, 3 Aug 2007 23:09:26 GMT"
}
] | 2011-11-09T00:00:00 | [
[
"Gonzalez",
"Diego Luis",
"",
"Universidad de los Andes,\n Bogota, Colombia"
],
[
"Tellez",
"Gabriel",
"",
"Universidad de los Andes,\n Bogota, Colombia"
]
] |
0704.2620 | Moshe Elitzur | Moshe Elitzur | Recent Developments in Maser Theory | Review presented at IAU symposium 242, "Astrophysical Masers and
their Environments" | null | 10.1017/S1743921307012495 | null | astro-ph | null | This review covers selected developments in maser theory since the previous
meeting, "Cosmic Masers: From Proto-Stars to Black Holes" (Migenes & Reid
2002). Topics included are time variability of fundamental constants, pumping
of OH megamasers and indicators for differentiating disks from bi-directional
outflows.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 21:56:57 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Elitzur",
"Moshe",
""
]
] |
0704.2621 | Abdul Rumaiz | Abdul K Rumaiz, Bakhtyar Ali, Abdullah Ceylan, M. Boggs, T. Beebe and
S. Ismat Shah | Experimental studies on vacancy induced ferromagnetism in undoped TiO2 | 20 pages, 9 figure | null | 10.1016/j.ssc.2007.08.034 | null | cond-mat.mtrl-sci | null | Room temperature ferromagnetism is observed in undoped TiO2 films deposited
on Si substrates using pulsed laser deposition (PLD). The ferromagnetic
properties of the samples depend on the oxygen partial pressure during the PLD
synthesis. The appearance of higher binding energy component (HBEC) in the
oxygen 1s core peak from x-ray photoelectron spectroscopy (XPS) suggests the
presence of oxygen vacancies in these samples. The amount of oxygen during the
synthesis determines the vacancy concentration in the samples which is directly
related to the magnetic behavior of the samples. The magnetic moment decreases
with oxygen vacancy concentration in the samples. Valence band measurements
were performed to study the electronic structure of both stoichometric and
reduced TiO2. The analyses show the presence of Ti 3d band near the Fermi level
in reduced TiO2 samples. These bands are otherwise empty in stoichiometric TiO2
and reside in the conduction band which makes them unobservable by XPS. The
existence of this Ti 3d band near the Fermi level can possibly lead to Stoner
splitting of the band.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 22:04:02 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Rumaiz",
"Abdul K",
""
],
[
"Ali",
"Bakhtyar",
""
],
[
"Ceylan",
"Abdullah",
""
],
[
"Boggs",
"M.",
""
],
[
"Beebe",
"T.",
""
],
[
"Shah",
"S. Ismat",
""
]
] |
0704.2622 | Sergei Mukhin I | S.I. Mukhin, A. Mesaros, Jan Zaanen, F.V. Kusmartsev | Metallic stripes and the universality of the anomalous half-breathing
phonon in high-Tc cuprates | 4 pages, 4 figures, submitted to PRL 18.04.2007 | null | null | null | cond-mat.str-el cond-mat.supr-con | null | We demonstrate that the strong anomalies in the high frequency LO-phonon
spectrum in cuprate superconductors can in principle be explained by the
enhanced electronic polarizability associated with the self-organized one
dimensionality of metallic stripes. Contrary to the current interpretation in
terms of transversal stripe fluctuations, the anomaly should occur at momenta
parallel to the stripes. The doping dependence of the anomaly is naturally
explained, and we predict that the phonon line-width and the spread of the
anomaly in the transverse momentum decrease with increasing temperature while
high resolution measurements should reveal a characteristic substructure to the
anomaly.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 22:21:20 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Mukhin",
"S. I.",
""
],
[
"Mesaros",
"A.",
""
],
[
"Zaanen",
"Jan",
""
],
[
"Kusmartsev",
"F. V.",
""
]
] |
0704.2623 | Daniel Heinzen | X. Du, Shoupu Wan, Emek Yesilada, C. Ryu, D. J. Heinzen, Z. X. Liang,
and Biao Wu | Bragg spectroscopy of a superfluid Bose-Hubbard gas | 11 pages, 4 figures | null | 10.1088/1367-2630/12/8/083025 | null | cond-mat.other | null | Bragg spectroscopy is used to measure excitations of a trapped,
quantum-degenerate gas of 87Rb atoms in a 3-dimensional optical lattice. The
measurements are carried out over a range of optical lattice depths in the
superfluid phase of the Bose-Hubbard model. For fixed wavevector, the resonant
frequency of the excitation is found to decrease with increasing lattice depth.
A numerical calculation of the resonant frequencies based on Bogoliubov theory
shows a less steep rate of decrease than the measurements.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 22:11:20 GMT"
},
{
"version": "v2",
"created": "Wed, 25 Apr 2007 14:23:35 GMT"
}
] | 2015-05-13T00:00:00 | [
[
"Du",
"X.",
""
],
[
"Wan",
"Shoupu",
""
],
[
"Yesilada",
"Emek",
""
],
[
"Ryu",
"C.",
""
],
[
"Heinzen",
"D. J.",
""
],
[
"Liang",
"Z. X.",
""
],
[
"Wu",
"Biao",
""
]
] |
0704.2624 | Claudio Pastorino | C. Pastorino, T. Kreer, M. Mueller and K. Binder | Comparison of Dissipative Particle Dynamics and Langevin thermostats for
out-of-equilibrium simulations of polymeric systems | 12 pages, introduction improved, references added, to appear in Phys.
Rev. E | Phys. Rev. E 76, 026706 (2007) | 10.1103/PhysRevE.76.026706 | null | cond-mat.soft cond-mat.stat-mech | null | In this work we compare and characterize the behavior of Langevin and
Dissipative Particle Dynamics (DPD) thermostats in a broad range of
non-equilibrium simulations of polymeric systems. Polymer brushes in relative
sliding motion, polymeric liquids in Poiseuille and Couette flows, and
brush-melt interfaces are used as model systems to analyze the efficiency and
limitations of different Langevin and DPD thermostat implementations. Widely
used coarse-grained bead-spring models under good and poor solvent conditions
are employed to assess the effects of the thermostats. We considered
equilibrium, transient, and steady state examples for testing the ability of
the thermostats to maintain constant temperature and to reproduce the
underlying physical phenomena in non-equilibrium situations. The common
practice of switching-off the Langevin thermostat in the flow direction is also
critically revisited. The efficiency of different weight functions for the DPD
thermostat is quantitatively analyzed as a function of the solvent quality and
the non-equilibrium situation.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 22:50:13 GMT"
},
{
"version": "v2",
"created": "Tue, 31 Jul 2007 17:23:21 GMT"
}
] | 2007-08-31T00:00:00 | [
[
"Pastorino",
"C.",
""
],
[
"Kreer",
"T.",
""
],
[
"Mueller",
"M.",
""
],
[
"Binder",
"K.",
""
]
] |
0704.2625 | Andrei Teleman | Andrei Teleman | Harmonic sections in sphere bundles, normal neighborhoods of reduction
loci, and instanton moduli spaces on definite 4-manifolds | LaTeX, 45 pages | Geom. Topol. 11 (2007) 1681-1730 | 10.2140/gt.2007.11.1681 | null | math.GT math.DG | null | We prove an existence theorem for gauge invariant $L^2$-normal neighborhoods
of the reduction loci in the space ${\cal A}_a(E)$ of oriented connections on a
fixed Hermitian 2-bundle $E$. We use this to obtain results on the topology of
the moduli space ${\cal B}_a(E)$ of (non-necessarily irreducible) oriented
connections, and to study the Donaldson $\mu$-classes globally around the
reduction loci. In this part of the article we use essentially the concept of
harmonic section in a sphere bundle with respect to an Euclidean connection.
Second, we concentrate on moduli spaces of instantons on definite 4-manifolds
with arbitrary first Betti number. We prove strong generic regularity results
which imply (for bundles with "odd" first Chern class) the existence of a
connected, dense open set of "good" metrics for which all the reductions in the
Uhlenbeck compactification of the moduli space are simultaneously regular.
These results can be used to define new Donaldson type invariants for definite
4-manifolds. The idea behind this construction is to notice that, for a good
metric $g$, the geometry of the instanton moduli spaces around the reduction
loci is always the same, independently of the choice of $g$. The connectedness
of the space of good metrics is important, in order to prove that no
wall-crossing phenomena (jumps of invariants) occur. Moreover, we notice that,
for low instanton numbers, the corresponding moduli spaces are a priori compact
and contain no reductions at all so, in these cases, the existence of
well-defined Donaldson type invariants is obvious. The natural question is to
decide whether these new Donaldson type invariants yield essentially new
differential topological information on the base manifold have, or have a
purely topological nature.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 22:22:37 GMT"
}
] | 2014-11-11T00:00:00 | [
[
"Teleman",
"Andrei",
""
]
] |
0704.2626 | Benjamin Huard | B. Huard, J.A. Sulpizio, N. Stander, K. Todd, B. Yang and D.
Goldhaber-Gordon | Transport measurements across a tunable potential barrier in graphene | 5 pages, 5 figures | Physical Review Letters 98, 236803 (2007) | 10.1103/PhysRevLett.98.236803 | Supplementary material on
ftp://ftp.aip.org/epaps/phys_rev_lett/E-PRLTAO-98-018724/supplementarymaterial.pdf | cond-mat.mes-hall | null | The peculiar nature of electron scattering in graphene is among many exciting
theoretical predictions for the physical properties of this material. To
investigate electron scattering properties in a graphene plane, we have created
a gate-tunable potential barrier within a single-layer graphene sheet. We
report measurements of electrical transport across this structure as the
tunable barrier potential is swept through a range of heights. When the barrier
is sufficiently strong to form a bipolar junctions (npn or pnp) within the
graphene sheet, the resistance across the barrier sharply increases. We compare
these results to predictions for both diffusive and ballistic transport, as the
barrier rises on a length scale comparable to the mean free path. Finally, we
show how a magnetic field modifies transport across the barrier.
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 01:10:48 GMT"
},
{
"version": "v2",
"created": "Thu, 7 Jun 2007 18:40:39 GMT"
}
] | 2007-06-19T00:00:00 | [
[
"Huard",
"B.",
""
],
[
"Sulpizio",
"J. A.",
""
],
[
"Stander",
"N.",
""
],
[
"Todd",
"K.",
""
],
[
"Yang",
"B.",
""
],
[
"Goldhaber-Gordon",
"D.",
""
]
] |
0704.2627 | Holger Mueller | Holger Mueller, Sheng-wey Chiow, and Steven Chu | Atom-wave diffraction between the Raman-Nath and the Bragg regime:
Effective Rabi frequency, losses, and phase shifts | Minor additions, more concise text. To appear in Phys. Rev. A. 20
pages, 10 figures | Phys. Rev. A 77, 023609 (2008) | 10.1103/PhysRevA.77.023609 | null | physics.atom-ph | null | We present an analytic theory of the diffraction of (matter) waves by a
lattice in the "quasi-Bragg" regime, by which we mean the transition region
between the long-interaction Bragg and "channelling" regimes and the
short-interaction Raman-Nath regime. The Schroedinger equation is solved by
adiabatic expansion, using the conventional adiabatic approximation as a
starting point, and re-inserting the result into the Schroedinger equation to
yield a second order correction. Closed expressions for arbitrary pulse shapes
and diffraction orders are obtained and the losses of the population to output
states otherwise forbidden by the Bragg condition are derived. We consider the
phase shift due to couplings of the desired output to these states that depends
on the interaction strength and duration and show how these can be kept
negligible by a choice of smooth (e.g., Gaussian) envelope functions even in
situations that substantially violate the adiabaticity condition. We also give
an efficient method for calculating the effective Rabi frequency (which is
related to the eigenvalues of Mathieu functions) in the quasi-Bragg regime.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 22:31:10 GMT"
},
{
"version": "v2",
"created": "Wed, 20 Jun 2007 20:31:52 GMT"
},
{
"version": "v3",
"created": "Thu, 6 Dec 2007 04:46:47 GMT"
}
] | 2008-02-08T00:00:00 | [
[
"Mueller",
"Holger",
""
],
[
"Chiow",
"Sheng-wey",
""
],
[
"Chu",
"Steven",
""
]
] |
0704.2628 | Jamal Jalilian-Marian | Jamal Jalilian-Marian | Average $p_t$ as a probe of high energy QCD dynamics | 8 pages, 3 figures | Nucl.Phys.A812:140-148,2008 | 10.1016/j.nuclphysa.2008.08.009 | BCCUNY-HEP-07-04 | hep-ph nucl-ex nucl-th | null | Average transverse momentum of hadrons produced in high energy collisions is
proposed as a diagnostic probe of high density (saturation) physics. We show
that by introducing and varying a transverse momentum cutoff in the definition
of the average transverse momentum, one can eliminate the uncertainty in the
overall magnitude of the leading order hadron production cross section in high
energy collisions, and semi-quantitatively map the different dynamical regions
predicted by the saturation physics. We discuss the applications of this method
to pion production at RHIC and LHC and make quantitative predictions for the
average transverse momentum of produced pions in the kinematics appropriate for
the RHIC and LHC experiments.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 22:35:16 GMT"
}
] | 2010-03-25T00:00:00 | [
[
"Jalilian-Marian",
"Jamal",
""
]
] |
0704.2629 | Andrei Teleman | Andrei Teleman | Families of holomorphic bundles | LaTeX, 26 pages | null | null | null | math.DG math.AG math.CV | null | The first goal of the article is to solve several fundamental problems in the
theory of holomorphic bundles over non-algebraic manifolds: For instance we
prove that stability and semi-stability are Zariski open properties in families
when the Gauduchon degree map is a topological invariant, or when the parameter
manifold is compact. Second we show that, for a generically stable family of
bundles over a K\"ahler manifold, the Petersson-Weil form extends as a closed
positive current on the whole parameter space of the family. This extension
theorem uses classical tools from Yang-Mills theory developed by Donaldson
(e.g. the Donaldson functional and the heat equation for Hermitian metrics on a
holomorphic bundle). We apply these results to study families of bundles over a
K\"ahlerian manifold $Y$ parameterized by a non-K\"ahlerian surface $X$,
proving that such families must satisfy very restrictive conditions. These
results play an important role in our program to prove existence of curves on
class VII surfaces.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 22:58:53 GMT"
},
{
"version": "v2",
"created": "Mon, 14 May 2007 08:40:53 GMT"
},
{
"version": "v3",
"created": "Mon, 14 May 2007 22:23:03 GMT"
},
{
"version": "v4",
"created": "Wed, 16 May 2007 12:17:11 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Teleman",
"Andrei",
""
]
] |
0704.2630 | Mark Srednicki | James B. Hartle and Mark Srednicki | Are We Typical? | 7 pages; some clarifications of language and a reference added in v2;
minor clarification added in v3 | Phys.Rev.D75:123523,2007 | 10.1103/PhysRevD.75.123523 | null | hep-th gr-qc | null | Bayesian probability theory is used to analyze the oft-made assumption that
humans are typical observers in the universe. Some theoretical calculations
make the {\it selection fallacy} that we are randomly chosen from a class of
objects by some physical process, despite the absence of any evidence for such
a process, or any observational evidence favoring our typicality. It is
possible to favor theories in which we are typical by appropriately choosing
their prior probabilities, but such assumptions should be made explicit to
avoid confusion.
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 18:27:09 GMT"
},
{
"version": "v2",
"created": "Wed, 2 May 2007 17:45:51 GMT"
},
{
"version": "v3",
"created": "Thu, 17 May 2007 00:05:03 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Hartle",
"James B.",
""
],
[
"Srednicki",
"Mark",
""
]
] |
0704.2631 | Alan L. T. Paterson | Alan L. T. Paterson | The E-theoretic descent functor for groupoids | 21 pages | null | null | null | math.OA math.KT | null | The paper establishes, for a wide class of locally compact groupoids
$\Gamma$, the E-theoretic descent functor at the $C^{*}$-algebra level, in a
way parallel to that established for locally compact groups by Guentner, Higson
and Trout. The second section shows that $\Gamma$-actions on a
$C_{0}(X)$-algebra $B$, where $X$ is the unit space of $\Gamma$, can be
usefully formulated in terms of an action on the associated bundle
$B^{\sharp}$. The third section shows that the functor $B\to C^{*}(\Gamma,B)$
is continuous and exact, and uses the disintegration theory of J. Renault. The
last section establishes the existence of the descent functor under a very mild
condition on $\Gamma$, the main technical difficulty involved being that of
finding a $\Gamma$-algebra that plays the role of C_{b}(T,B)^{cont}$ in the
group case.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 23:20:26 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Paterson",
"Alan L. T.",
""
]
] |
0704.2632 | Zhenyu Yan | Zhenyu Yan, Sergey V. Buldyrev, Pradeep Kumar, Nicolas Giovambattista,
Pablo G. Debenedetti and H. Eugene Stanley | Structure of the First and Second Neighbor Shells of Water: Quantitative
Relation with Translational and Orientational Order | 12 pages, 5 figures | Phys. Rev. E 76, 051201 (2007) | 10.1103/PhysRevE.76.051201 | null | cond-mat.soft cond-mat.stat-mech | null | We perform molecular dynamics simulation of water using the TIP5P model to
quantify structural order in both the first shell (defined by four nearest
neighbors)and second shell (defined by twelve next-nearest neighbors) of a
central water molecule. We find the anomalous decrease of orientational order
upon compression occurs in both shells, but the anomalous decrease of
translational order upon compression occurs {\it mainly in the second shell}.
The decreases of translational and orientational orders upon compression
("structural anomaly") are thus correlated only in the second shell. Our
findings quantitatively confirm the qualitative idea that the thermodynamic,
dynamic and structural anomalies of water are related to changes in the second
shell upon compression.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 23:40:26 GMT"
}
] | 2007-12-12T00:00:00 | [
[
"Yan",
"Zhenyu",
""
],
[
"Buldyrev",
"Sergey V.",
""
],
[
"Kumar",
"Pradeep",
""
],
[
"Giovambattista",
"Nicolas",
""
],
[
"Debenedetti",
"Pablo G.",
""
],
[
"Stanley",
"H. Eugene",
""
]
] |
0704.2633 | Harold Widom | Craig A. Tracy, Harold Widom | Integral Formulas for the Asymmetric Simple Exclusion Process | 36 pages, LaTeX file. Version 3 corrects the proof of Theorem 2.1 | Commun. Math. Phys. 279, 815--844 (2008). Erratum: Commun. Math.
Phys. 304, 875-878 (2011) | 10.1007/s00220-008-0443-3 | null | math.PR math-ph math.MP | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | In this paper we obtain general integral formulas for probabilities in the
asymmetric simple exclusion process (ASEP) on the integer lattice with nearest
neighbor hopping rates p to the right and q=1-p to the left. For the most part
we consider an N-particle system but for certain of these formulas we can take
the limit as N goes to infinity. First we obtain, for the N-particle system, a
formula for the probability of a configuration at time t, given the initial
configuration. For this we use Bethe Ansatz ideas to solve the master equation,
extending a result of Schuetz for the case N=2. The main results of the paper,
derived from this, are integral formulas for the probability, for given initial
configuration, that the m'th left-most particle is at x at time t. In one of
these formulas we can take the limit as N goes to infinity, and it gives the
probability for an infinite system where the initial configuration is bounded
on one side. For the special case of the totally asymmetric simple exclusion
process (TASEP) our formulas reduce to the known ones.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 23:44:42 GMT"
},
{
"version": "v2",
"created": "Thu, 26 Apr 2007 19:31:38 GMT"
},
{
"version": "v3",
"created": "Thu, 17 Mar 2011 16:36:18 GMT"
}
] | 2011-08-12T00:00:00 | [
[
"Tracy",
"Craig A.",
""
],
[
"Widom",
"Harold",
""
]
] |
0704.2634 | Andrei Teleman | Andrei Teleman | Instantons and curves on class VII surfaces | LaTeX 48 pages; RV: minor corrections, new paragraph dedicated to the
structure of the moduli space around the circles of reductions; RV: minor
corrections, to appear in Annals of Mathematics | null | null | null | math.DG math.AG math.CV math.GT | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We develop a general strategy, based on gauge theoretical methods, to prove
existence of curves on class VII surfaces. We prove that, for $b_2=2$, every
minimal class VII surface has a cycle of rational curves hence, by a result of
Nakamura, is a global deformation of a one parameter family of blown up primary
Hopf surfaces. The case $b_2=1$ has been solved in a previous article. The
fundamental object intervening in our strategy is the moduli space ${\mathcal
M}^{\pst}(0,{\mathcal K})$ of polystable bundles ${\mathcal E}$ with
$c_2({\mathcal E})=0$, $\det({\mathcal E})={\mathcal K}$. For large $b_2$ the
geometry of this moduli space becomes very complicated. The case $b_2=2$
treated here in detail requires new ideas and difficult techniques of both
complex geometric and gauge theoretical nature.
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 05:40:35 GMT"
},
{
"version": "v2",
"created": "Sun, 22 Apr 2007 16:33:36 GMT"
},
{
"version": "v3",
"created": "Tue, 18 Sep 2007 17:35:01 GMT"
},
{
"version": "v4",
"created": "Tue, 15 Sep 2009 17:29:29 GMT"
}
] | 2009-09-15T00:00:00 | [
[
"Teleman",
"Andrei",
""
]
] |
0704.2635 | Kurt Langfeld | Kurt Langfeld | Improved actions and asymptotic scaling in lattice Yang-Mills theory | minor modifications, improved presentation | Phys.Rev.D76:094502,2007 | 10.1103/PhysRevD.76.094502 | null | hep-lat hep-th | null | Improved actions in SU(2) and SU(3) lattice gauge theories are investigated
with an emphasis on asymptotic scaling. A new scheme for tadpole improvement is
proposed. The standard but heuristic tadpole improvement emerges from a mean
field approximation from the new approach. Scaling is investigated by means of
the large distance static quark potential. Both, the generic and the new
tadpole scheme yield significant improvements on asymptotic scaling when
compared with loop improved actions. A study of the rotational symmetry
breaking terms, however, reveals that only the new improvement scheme
efficiently eliminates the leading irrelevant term from the action.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 23:52:53 GMT"
},
{
"version": "v2",
"created": "Wed, 5 Sep 2007 12:45:23 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Langfeld",
"Kurt",
""
]
] |
0704.2636 | Geoffrey Bicknell | Geoffrey V. Bicknell and Jianke Li | Linkage between Accretion Disks and Blazars | Submiteed to the Astrophysics & Space Science special issue on the
5th Stromlo Symposium | Astrophys.Space Sci.311:275-279,2007 | 10.1007/s10509-007-9582-9 | null | astro-ph | null | The magnetic field in an accretion disk is estimated assuming that all of the
angular momentum within prescribed accretion disk radii is removed by a jet.
The magnetic field estimated at the base of the jet is extrapolated to the
blazar emission region using a model for a relativistic axisymmetric jet
combined with some simplifying assumptions based on the relativistic nature of
the flow. The extrapolated magnetic field is compared with estimates based upon
the synchrotron and inverse Compton emission from three blazars, MKN 501, MKN
421 and PKS 2155-304. The magnetic fields evaluated from pure synchrotron self-
Compton models are inconsistent with the magnetic fields extrapolated in this
way. However, in two cases inverse Compton models in which a substantial part
of the soft photon field is generated locally agree well, mainly because these
models imply magnetic field strengths which are closer to being consistent with
Poynting flux dominated jets. This comparison is based on estimating the mass
accretion rate from the jet energy flux. Further comparisons along these lines
will be facilitated by independent estimates of the mass accretion rate in
blazars and by more detailed models for jet propagation near the black hole.
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 04:13:37 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"Bicknell",
"Geoffrey V.",
""
],
[
"Li",
"Jianke",
""
]
] |
0704.2637 | Grant Newsham Mr. | G. Newsham and D. M. Terndrup (Ohio State) | Observational consequences of the hypothesized helium rich stellar
population in Omega Centauri | 37 pages, 10 figures, accepted for publication in ApJ | Astrophys.J.664:332-342,2007 | 10.1086/518758 | null | astro-ph | null | In response to the proposed high helium content stars as an explanation for
the double main sequence observed in Omega Centauri, we investigated the
consequences of such stars elsewhere on the color-magnitude diagram. We
concentrated on the horizontal branch where the effects of high helium are
expected to show themselves more clearly. In the process, we developed a
procedure for comparing the mass loss suffered by differing stellar populations
in a physically motivated manner. High helium stars in the numbers proposed
seem absent from the horizontal branch of Omega Centauri unless their mass loss
history is very different from that of the majority metal-poor stars. It is
possible to generate a double main sequence with existing Omega Centauri stars
via accretion of helium rich pollution consistent with the latest AGB ejecta
theoretical yields, and such polluted stars are consistent with the observed HB
morphology of Omega Centauri. Polluted models are consistent with observed
merging of the main sequences as opposed to our models of helium rich stars.
Using the (B-R)/(B+V+R) statistic, we find that the high helium bMS stars
require an age difference compared to the rMS stars that is too great, whereas
the pollution scenario stars have no such conflict for inferred Omega Centauri
mass losses.
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 00:19:10 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"Newsham",
"G.",
"",
"Ohio State"
],
[
"Terndrup",
"D. M.",
"",
"Ohio State"
]
] |
0704.2638 | Andrei Teleman | Andrei Teleman | Donaldson theory on non-K\"ahlerian surfaces and class $VII$ surfaces
with $b_2=1$ | LaTeX, 29 pages | Inv. math, Volume 162, Number 3, December 2005, 493-521 | null | null | math.DG math.AG math.CV math.GT | null | We prove that any class $VII$ surface with $b_2=1$ has curves. This implies
the "Global Spherical Shell conjecture" in the case $b_2=1$: Any minimal class
$VII$ surface with $b_2=1$ admits a global spherical shell, hence it is
isomorphic to one of the surfaces in the known list. The main idea of the proof
is to show that a certain moduli space of PU(2)-instantons on a surface $X$
with no curves (if such a surface existed) would contain a closed Riemann
surface $Y$ whose general points correspond to non-filtrable holomorphic
bundles on $X$. Then we pass from a family of bundles on $X$ parameterized by
$Y$ to a family of bundles on $Y$ parameterized by $X$, and we use the
algebraicity of $Y$ to obtain a contradiction. The proof uses essentially
techniques from Donaldson theory: compactness theorems for moduli spaces of
PU(2)-instantons and the Kobayashi-Hitchin correspondence on surfaces.
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 05:48:00 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Teleman",
"Andrei",
""
]
] |
0704.2639 | Jin Hong Kim | Jin Hong Kim | Isolated fixed points and moment maps of symplectic manifolds | null | null | null | null | math.SG math.GT | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Withdrawn due to an incompleteness of the main results.
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 00:19:27 GMT"
},
{
"version": "v2",
"created": "Tue, 5 Jun 2007 03:09:56 GMT"
},
{
"version": "v3",
"created": "Tue, 5 Aug 2008 07:38:29 GMT"
}
] | 2008-08-05T00:00:00 | [
[
"Kim",
"Jin Hong",
""
]
] |
0704.2640 | Ray Norris | Ray P. Norris, Steven Tingay, Chris Phillips, Enno Middelberg, Adam
Deller, Philip N. Appleton | VLBI detection of an Infrared-Faint Radio Source | accepted by MNRAS | Mon.Not.Roy.Astron.Soc.378:1434-1438,2007 | 10.1111/j.1365-2966.2007.11883.x | null | astro-ph | null | Infrared-Faint Radio Sources represent a new and unexpected class of object
which is bright at radio wavelengths but unusually faint at infrared
wavelengths. If, like most mJy radio sources, they were either conventional
active or star-forming galaxies in the local Universe, we would expect them to
be detectable at infrared wavelengths, and so their non-detection by the
Spitzer Space Telescope is surprising. Here we report the detection of one of
these sources using Very Long Baseline Interferometry, from which we conclude
that the sources are driven by Active Galactic Nuclei. We suggest that these
sources are either normal radio-loud quasars at high redshift or abnormally
obscured radio galaxies.
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 00:26:04 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"Norris",
"Ray P.",
""
],
[
"Tingay",
"Steven",
""
],
[
"Phillips",
"Chris",
""
],
[
"Middelberg",
"Enno",
""
],
[
"Deller",
"Adam",
""
],
[
"Appleton",
"Philip N.",
""
]
] |
0704.2641 | Todd Hunter | T.R. Hunter, A.E.T. Schinckel, A.B. Peck, R.D. Christensen, R.
Blundell, A. Camacho, F. Patt, K. Sakamoto, K.H. Young | Phase Closure at 691 GHz using the Submillimeter Array | 13 pages, 11 figures, originally presented as a poster at the 201st
AAS meeting held in Seattle, WA in January 2003 | null | null | null | astro-ph | null | Phase closure at 682 GHz and 691 GHz was first achieved using three antennas
of the Submillimeter Array (SMA) interferometer located on Mauna Kea, Hawaii.
Initially, phase closure was demonstrated at 682.5 GHz on Sept. 19, 2002 using
an artificial ground-based "beacon" signal. Subsequently, astronomical
detections of both Saturn and Uranus were made at the frequency of the CO(6-5)
transition (691.473 GHz) on all three baselines on Sept. 22, 2002. While the
larger planets such as Saturn are heavily resolved even on these short
baselines (25.2m, 25.2m and 16.4m), phase closure was achieved on Uranus and
Callisto. This was the first successful experiment to obtain phase closure in
this frequency band. The CO(6-5) line was also detected towards Orion BN/KL and
other Galactic sources, as was the vibrationally-excited 658 GHz water maser
line toward evolved stars. We present these historic detections, as well as the
first arcsecond-scale images obtained in this frequency band.
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 00:45:25 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Hunter",
"T. R.",
""
],
[
"Schinckel",
"A. E. T.",
""
],
[
"Peck",
"A. B.",
""
],
[
"Christensen",
"R. D.",
""
],
[
"Blundell",
"R.",
""
],
[
"Camacho",
"A.",
""
],
[
"Patt",
"F.",
""
],
[
"Sakamoto",
"K.",
""
],
[
"Young",
"K. H.",
""
]
] |
0704.2642 | Ryan Porter | R. L. Porter and G. J. Ferland | Revisiting He-like X-ray Emission Line Plasma Diagnostics | 28 pages, 7 figures, accepted to ApJ | Astrophys.J.664:586-595,2007 | 10.1086/518882 | null | astro-ph | null | A complete model of helium-like line and continuum emission has been
incorporated into the plasma simulation code Cloudy. All elements between He
and Zn are treated, any number of levels can be considered, and radiative and
collisional processes are included. This includes photoionization from all
levels, line transfer including continuum pumping and destruction by background
opacities, scattering, and collisional processes. The model is calculated
self-consistently along with the ionization and thermal structure of the
surrounding nebula. The result is a complete line and continuum spectrum of the
plasma. Here we focus on the ions of the He I sequence and reconsider the
standard helium-like X-ray diagnostics. We first consider semi-analytical
predictions and compare these with previous work in the low-density,
optically-thin limit. We then perform numerical calculations of helium-like
X-ray emission (such as is observed in some regions of Seyferts) and predict
line ratios as a function of ionizing flux, hydrogen density, and column
density. In particular, we demonstrate that, in photoionized plasmas, the
$R$-ratio, a density indicator in a collisional plasma, depends on the
ionization fraction and is strongly affected by optical depth for large column
densities. We also introduce the notion that the $R$-ratio is a measure of the
incident continuum at UV wavelengths. The $G$-ratio, which is
temperature-sensitive in a collisional plasma, is also discussed, and shown to
be strongly affected by continuum pumping and optical depth as well. These
distinguish a photoionized plasma from the more commonly studied collisional
case.
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 01:04:06 GMT"
}
] | 2019-08-19T00:00:00 | [
[
"Porter",
"R. L.",
""
],
[
"Ferland",
"G. J.",
""
]
] |
0704.2643 | Rohta Takahashi | Rohta Takahashi, Ken-Ya Watarai | Eclipsing light curves for accretion flows around a rotating black hole
and atmospheric effects of the companion star | Takahashi R., Watarai K., 2007, MNRAS, 374, 1515 | Mon.Not.Roy.Astron.Soc.374:1515,2007 | 10.1111/j.1365-2966.2006.11262.x | null | astro-ph | null | We calculate eclipsing light curves for accretion flows around a rotating
black hole taking into account the atmospheric effects of the companion star.
In the cases of no atmospheric effects, the light curves contain the
information of the black hole spin because most of the X-ray photons around 1
keV usually come from the blueshifted part of the accretion flow near the black
hole shadow, and the size and the position of the black hole shadow depend on
the spin. In these cases, when most of the emission comes from the vicinity of
the event horizon, the light curves become asymmetric at ingress and egress. We
next investigate the atmospheric absorption and scattering effects of the
companion stars. By using the solar-type atmospheric model, we have taken into
account the atmospheric effects of the companion star, such as the
photoionization by HI and HeI. We found that the eclipsing light curves
observed at 1 keV possibly contain the information of the black hole spin.
However, in our atmospheric model, the effects of the atmosphere are much
larger than the effects of the black hole spin. Therefore, even in the case
that the light curves contain the information of the black hole spin, it may be
difficult to extract the information of the black hole spin if we do not have
the realistic atmospheric profiles, such as the temperature, and the number
densities for several elements. Even in such cases, the light-curve asymmetries
due to the rotation of the accretion disc exist. Only when we have the reliable
atmospheric model, in principle, the information of the strong-gravity regions,
such as the black hole spin, can be obtained from the eclipsing light curves.
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 01:11:09 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"Takahashi",
"Rohta",
""
],
[
"Watarai",
"Ken-Ya",
""
]
] |
0704.2644 | Maxim Raginsky | Maxim Raginsky | Joint universal lossy coding and identification of stationary mixing
sources | 5 pages, 1 eps figure; to appear in Proc. ISIT 2007 | null | null | null | cs.IT cs.LG math.IT | null | The problem of joint universal source coding and modeling, treated in the
context of lossless codes by Rissanen, was recently generalized to fixed-rate
lossy coding of finitely parametrized continuous-alphabet i.i.d. sources. We
extend these results to variable-rate lossy block coding of stationary ergodic
sources and show that, for bounded metric distortion measures, any finitely
parametrized family of stationary sources satisfying suitable mixing,
smoothness and Vapnik-Chervonenkis learnability conditions admits universal
schemes for joint lossy source coding and identification. We also give several
explicit examples of parametric sources satisfying the regularity conditions.
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 01:25:22 GMT"
}
] | 2007-07-13T00:00:00 | [
[
"Raginsky",
"Maxim",
""
]
] |
0704.2645 | Noboru Nakanishi | Noboru Nakanishi | Unobservable Higgs Boson and Spontaneous Violation of Lorentz Invariance | 8 pages | null | 10.1143/PTP.118.913 | null | hep-th | null | The standard theory of elementary particle physics is modified in such a way
that the Higgs boson becomes unobservable and Lorentz invariance is slightly
violated at the level of the S-matrix. The basic technique of realizing these
properties without violating the unitarity of the physical S-matrix is the use
of the complex-ghost quantum field theory.
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 01:42:34 GMT"
},
{
"version": "v2",
"created": "Mon, 13 Aug 2007 07:15:37 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Nakanishi",
"Noboru",
""
]
] |
0704.2646 | Qi Li | Qi Li | On Multiplier Hermitian Structures on Compact Kahler Manifolds | Minor change made at the end of the section 1 | null | null | null | math.DG | null | Mabuchi introduced multiplier Hermitian structures on compact Kahler
manifolds and defined metrics similar to Kahler-Einstein metrics under these
structures. In this note we generalize the inequality of Moser-Trudinger type
on Kahler-Einstein manifolds to this case.
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 02:10:24 GMT"
},
{
"version": "v2",
"created": "Sat, 28 Apr 2007 07:04:18 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Li",
"Qi",
""
]
] |
0704.2647 | Muhammad Sharif | M. Sharif and Zahid Ahmad | High-Speed Cylindrical Collapse of Two Perfect Fluids | 11 pages, 1 figure, accepted for publication in Gen. Rel. Grav | Gen.Rel.Grav.39:1331-1344,2007 | 10.1007/s10714-007-0440-4 | null | gr-qc | null | In this paper, the study of the gravitational collapse of cylindrically
distributed two perfect fluid system has been carried out. It is assumed that
the collapsing speeds of the two fluids are very large. We explore this
condition by using the high-speed approximation scheme. There arise two cases,
i.e., bounded and vanishing of the ratios of the pressures with densities of
two fluids given by $c_s, d_s$. It is shown that the high-speed approximation
scheme breaks down by non-zero pressures $p_1, p_2$ when $c_s, d_s$ are bounded
below by some positive constants. The failure of the high-speed approximation
scheme at some particular time of the gravitational collapse suggests the
uncertainity on the evolution at and after this time. In the bounded case, the
naked singularity formation seems to be impossible for the cylindrical two
perfect fluids. For the vanishing case, if a linear equation of state is used,
the high-speed collapse does not break down by the effects of the pressures and
consequently a naked singularity forms. This work provides the generalisation
of the results already given by Nakao and Morisawa [1] for the perfect fluid.
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 02:20:10 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Sharif",
"M.",
""
],
[
"Ahmad",
"Zahid",
""
]
] |
0704.2648 | Svetlana Kotochigova | Svetlana Kotochigova | Prospects for making polar molecules with microwave fields | 4 pages, 5 figures | null | 10.1103/PhysRevLett.99.073003 | null | quant-ph | null | We propose a new mechanism to produce ultracold polar molecules with
microwave fields. The proposed mechanism converts trapped ultracold atoms of
different species into vibrationally excited molecules by a single microwave
transition and entirely depends on the existence of a permanent dipole moment
in the molecules. As opposed to production of molecules by photoassociation or
magnetic-field Feshbach resonances our method does not rely on the structure
and lifetime of excited states or existence of Feshbach resonances. In
addition, we determine conditions for optimal creation of polar molecules in
vibrationally excited states of the ground-state potential by changing
frequency and intensity of the microwave field. We also explore the possibility
to produce vibrationally cold molecules by combining the microwave field with
an optical Raman transition or by applying a microwave field to Feshbach
molecules. The production mechanism is illustrated for two polar molecules: KRb
and RbCs.
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 02:31:21 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Kotochigova",
"Svetlana",
""
]
] |
0704.2649 | Mike Steel Prof. | Mike Steel, Aki Mimoto, Arne O. Mooers | Hedging our bets: the expected contribution of species to future
phylogenetic diversity | 19 pages, 2 figures | null | null | null | q-bio.PE | null | If predictions for species extinctions hold, then the `tree of life' today
may be quite different to that in (say) 100 years. We describe a technique to
quantify how much each species is likely to contribute to future biodiversity,
as measured by its expected contribution to phylogenetic diversity. Our
approach considers all possible scenarios for the set of species that will be
extant at some future time, and weights them according to their likelihood
under an independent (but not identical) distribution on species extinctions.
Although the number of extinction scenarios can typically be very large, we
show that there is a simple algorithm that will quickly compute this index. The
method is implemented and applied to the prosimian primates as a test case, and
the associated species ranking is compared to a related measure (the `Shapley
index'). We describe indices for rooted and unrooted trees, and a modification
that also includes the focal taxon's probability of extinction, making it
directly comparable to some new conservation metrics.
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 02:37:58 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Steel",
"Mike",
""
],
[
"Mimoto",
"Aki",
""
],
[
"Mooers",
"Arne O.",
""
]
] |
0704.2650 | Douglas B. West | Armen S. Asratian (Linkoping University), Carl Johan Casselgren (Umea
University), Jennifer Vandenbussche (University of Illinois), Douglas B. West
(University of Illinois) | Proper path-factors and interval edge-coloring of (3,4)-biregular
bigraphs | 11 pages, 2 figures | null | null | null | math.CO | null | An interval coloring of a graph G is a proper coloring of E(G) by positive
integers such that the colors on the edges incident to any vertex are
consecutive. A (3,4)-biregular bigraph is a bipartite graph in which each
vertex of one part has degree 3 and each vertex of the other has degree 4; it
is unknown whether these all have interval colorings. We prove that G has an
interval coloring using 6 colors when G is a (3,4)-biregular bigraph having a
spanning subgraph whose components are paths with endpoints at 3-valent
vertices and lengths in {2,4,6,8}. We provide sufficient conditions for the
existence of such a subgraph.
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 03:15:44 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Asratian",
"Armen S.",
"",
"Linkoping University"
],
[
"Casselgren",
"Carl Johan",
"",
"Umea\n University"
],
[
"Vandenbussche",
"Jennifer",
"",
"University of Illinois"
],
[
"West",
"Douglas B.",
"",
"University of Illinois"
]
] |
0704.2651 | Lalitha Sankar | Lalitha Sankar, Yingbin Liang, H. Vincent Poor, Narayan B. Mandayam | Opportunistic Communications in an Orthogonal Multiaccess Relay Channel | To appear in the Proceedings of the 2007 IEEE International Symposium
on Information Theory, Nice, France, June 24 - 29, 2007 | null | 10.1109/ISIT.2007.4557396 | null | cs.IT math.IT | null | The problem of resource allocation is studied for a two-user fading
orthogonal multiaccess relay channel (MARC) where both users (sources)
communicate with a destination in the presence of a relay. A half-duplex relay
is considered that transmits on a channel orthogonal to that used by the
sources. The instantaneous fading state between every transmit-receive pair in
this network is assumed to be known at both the transmitter and receiver. Under
an average power constraint at each source and the relay, the sum-rate for the
achievable strategy of decode-and-forward (DF) is maximized over all power
allocations (policies) at the sources and relay. It is shown that the sum-rate
maximizing policy exploits the multiuser fading diversity to reveal the
optimality of opportunistic channel use by each user. A geometric
interpretation of the optimal power policy is also presented.
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 04:02:33 GMT"
}
] | 2016-11-17T00:00:00 | [
[
"Sankar",
"Lalitha",
""
],
[
"Liang",
"Yingbin",
""
],
[
"Poor",
"H. Vincent",
""
],
[
"Mandayam",
"Narayan B.",
""
]
] |
0704.2652 | Tatiana Medvedeva | T. Medvedeva, R. Chistov, et al (for the Belle Collaboration) | Observation of the Decay \bar{B0}-> Ds+ Lambda \bar{p} | 5 pages, 2 PostScript figures, 1 table | Phys.Rev.D76:051102,2007 | 10.1103/PhysRevD.76.051102 | null | hep-ex | null | We report the first observation of the decay \bar{B0} -> D_s^+ Lambda \bar{p}
with a statistical significance of 6.6 sigma. We measure Br(\bar{B0} -> Ds+
Lambda \bar{p}) = (2.9 \pm 0.7\pm 0.5 \pm 0.4)* 10^{-5}, where the first error
is statistical, the second is systematic and the third error comes fr\om the
uncertainty in Br(Ds+ -> phi pi+). The data used for this analysis was
accumulated at the Upsilon(4S) resonance, using the Belle detector at the KEKB
asymmetric-energy e+e- collider. The integrated luminosity of the data sample
is 414 fb-1, corresponding to 449*10^{6} B{\bar B} pairs.
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 04:24:35 GMT"
},
{
"version": "v2",
"created": "Wed, 26 Sep 2007 15:49:48 GMT"
}
] | 2019-08-12T00:00:00 | [
[
"Medvedeva",
"T.",
""
],
[
"Chistov",
"R.",
""
]
] |
0704.2653 | Ladygina Nadezhda | N.B. Ladygina | Investigation of Neutron--Deuteron Charge-Exchange Reaction at Small
Transfer Momentum | to be published in Phys.Atom.Nucl | Phys.Atom.Nucl.71:58-64,2008 | 10.1007/s11450-008-1006-y | null | nucl-th | null | Analysis of the $nd\to p(nn)$ reaction in a GeV-energy region is performed in
the framework based on the multiple-scattering theory for the few-nucleon
system. The special kinematic condition, when momentum transfer from neutron
beam to final proton closes to zero, is considered. The possibility to extract
the spin-dependent term of the elementary $np\to pn $ amplitude from
$nd$-breakup process is investigated. The energy dependence of the ratio
$R=\frac{d\sigma_{nd}} {d\Omega} / \frac{d\sigma_{np}}{d\Omega}$ is obtained
taking account of the final-state interaction of the two outgoing neutrons in
$^1 S_0$-state.
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 06:16:43 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Ladygina",
"N. B.",
""
]
] |
0704.2654 | Naoki Yamamoto | Naoki Yamamoto, Motoi Tachibana, Tetsuo Hatsuda, Gordon Baym | Phase structure, collective modes, and the axial anomaly in dense QCD | 24 pages, 7 figures | Phys.Rev.D76:074001,2007 | 10.1103/PhysRevD.76.074001 | TKYNT-07-10, SAGA-HE-233 | hep-ph | null | Using a general Ginzburg-Landau effective Lagrangian, we study the
topological structure and low-lying collective modes of dense QCD having both
chiral and diquark condensates, for two and three massless flavors. As we found
earlier, the QCD axial anomaly acts as an external field applied to the chiral
condensate in a color superconductor and, as a new critical point emerges,
leads to a crossover between the broken chiral symmetry and color
superconducting phases. At intermediate densities where both chiral and diquark
condensates are present, we derive a generalized Gell-Mann- Oakes-Renner
relation between the masses of pseudoscalar bosons and the magnitude of the
chiral and diquark-condensates. We show explicitly the continuity of the
ordinary pion at low densities to a generalized pion at high densities.
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 08:15:24 GMT"
},
{
"version": "v2",
"created": "Thu, 4 Oct 2007 02:24:47 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Yamamoto",
"Naoki",
""
],
[
"Tachibana",
"Motoi",
""
],
[
"Hatsuda",
"Tetsuo",
""
],
[
"Baym",
"Gordon",
""
]
] |
0704.2655 | Todd Hunter | T.R. Hunter, K.H. Young, R.D. Christensen, M.A. Gurwell | 658 GHz Vibrationally-Excited Water Masers with the Submillimeter Array | 8 pages, 6 figures, 3 tables; based on an oral presentation at IAU
conference 242: Astrophysical Masers and Their Environments, held in Alice
Springs, Australia (March 2007) | Astrophysical Masers and their Environments, Proceedings of the
International Astronomical Union, IAU Symposium, Volume 242, p. 481-488, 2008 | 10.1017/S1743921307013634 | null | astro-ph | null | Discovered in 1995 at the Caltech Submillimeter Observatory (CSO), the
vibrationally-excited water maser line at 658 GHz (455 micron) is seen in
oxygen-rich giant and supergiant stars. Because this maser can be so strong (up
to thousands of Janskys), it was very helpful during the commissioning phase of
the highest frequency band (620-700 GHz) of the Submillimeter Array (SMA)
interferometer. From late 2002 to early 2006, brief attempts were made to
search for emission from additional sources beyond the original CSO survey.
These efforts have expanded the source count from 10 to 16. The maser emission
appears to be quite compact spatially, as expected from theoretical
considerations; thus these objects can potentially be used as atmospheric phase
calibrators. Many of these objects also exhibit maser emission in the
vibrationally-excited SiO maser at 215 GHz. Because both maser lines likely
originate from a similar physical region, these objects can be used to test
techniques of phase transfer calibration between millimeter and submillimeter
bands. The 658 GHz masers will be important beacons to assess the performance
of the Atacama Large Millimeter Array (ALMA) in this challenging high-frequency
band.
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 05:27:41 GMT"
}
] | 2015-03-30T00:00:00 | [
[
"Hunter",
"T. R.",
""
],
[
"Young",
"K. H.",
""
],
[
"Christensen",
"R. D.",
""
],
[
"Gurwell",
"M. A.",
""
]
] |
0704.2656 | Silviu-Constantin Sararu | C. Bizdadea, E. M. Cioroianu, S. C. Sararu | Couplings between a collection of BF models and a set of three-form
gauge fields | 17 pages | Int. J. Mod. Phys. A21 (2006) 6477-6490 | 10.1142/S0217751X06034331 | null | hep-th | null | Consistent interactions that can be added to a free, Abelian gauge theory
comprising a collection of BF models and a set of three-form gauge fields are
constructed from the deformation of the solution to the master equation based
on specific cohomological techniques. Under the hypotheses of smooth, local, PT
invariant, Lorentz covariant, and Poincare invariant interactions, supplemented
with the requirement on the preservation of the number of derivatives on each
field with respect to the free theory, we obtain that the deformation procedure
modifies the Lagrangian action, the gauge transformations as well as the
accompanying algebra.
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 06:02:45 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Bizdadea",
"C.",
""
],
[
"Cioroianu",
"E. M.",
""
],
[
"Sararu",
"S. C.",
""
]
] |
0704.2657 | Frank Stefani | Mingtian Xu, Frank Stefani, Gunter Gerbeth | The integral equation approach to kinematic dynamo theory and its
application to dynamo experiments in cylindrical geometry | 22 pages, 14 figures | J.Comput.Phys.227:8130-8144,2008 | 10.1016/j.jcp.2008.05.009 | null | astro-ph | null | The conventional magnetic induction equation that governs hydromagnetic
dynamo action is transformed into an equivalent integral equation system. An
advantage of this approach is that the computational domain is restricted to
the region occupied by the electrically conducting fluid and to its boundary.
This integral equation approach is first employed to simulate kinematic dynamos
excited by Beltrami-like flows in a finite cylinder. The impact of externally
added layers around the cylinder on the onset of dynamo actions is
investigated. Then it is applied to simulate dynamo experiments within
cylindrical geometry including the von Karman sodium (VKS) experiment and the
Riga dynamo experiment. A modified version of this approach is utilized to
investigate magnetic induction effects under the influence of externally
applied magnetic fields which is also important to measure the proximity of a
given dynamo facility to the self-excitation threshold.
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 06:08:50 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"Xu",
"Mingtian",
""
],
[
"Stefani",
"Frank",
""
],
[
"Gerbeth",
"Gunter",
""
]
] |
0704.2658 | Silviu-Constantin Sararu | C. Bizdadea, E. M. Cioroianu, A. C. Lungu, S. C. Sararu | No cross-interactions between the Weyl graviton and the massless
Rarita-Schwinger field | 26 pages | AnnalenPhys.15:416-433,2006 | 10.1002/andp.200510181 | null | hep-th | null | The proof of the fact that there are no nontrivial, consistent
cross-couplings that can be added between the Weyl graviton and the massless
Rarita-Schwinger field is accomplished by means of a cohomological approach,
based on the deformation of the solution to the master equation from the
antifield-Becchi-Rouet-Stora-Tyutin (BRST) formalism. The procedure developed
here relies on the assumptions of locality, smoothness, (background) Lorentz
invariance, Poincare invariance, and preservation of the number of derivatives
with respect to each field (the last hypothesis was made only in antighost
number zero).
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 06:17:10 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Bizdadea",
"C.",
""
],
[
"Cioroianu",
"E. M.",
""
],
[
"Lungu",
"A. C.",
""
],
[
"Sararu",
"S. C.",
""
]
] |
0704.2659 | Chris Ng | Chris T. K. Ng, Deniz Gunduz, Andrea J. Goldsmith, Elza Erkip | Minimum Expected Distortion in Gaussian Layered Broadcast Coding with
Successive Refinement | To appear in the proceedings of the 2007 IEEE International Symposium
on Information Theory, Nice, France, June 24-29, 2007 | null | 10.1109/ISIT.2007.4557165 | null | cs.IT math.IT | null | A transmitter without channel state information (CSI) wishes to send a
delay-limited Gaussian source over a slowly fading channel. The source is coded
in superimposed layers, with each layer successively refining the description
in the previous one. The receiver decodes the layers that are supported by the
channel realization and reconstructs the source up to a distortion. In the
limit of a continuum of infinite layers, the optimal power distribution that
minimizes the expected distortion is given by the solution to a set of linear
differential equations in terms of the density of the fading distribution. In
the optimal power distribution, as SNR increases, the allocation over the
higher layers remains unchanged; rather the extra power is allocated towards
the lower layers. On the other hand, as the bandwidth ratio b (channel uses per
source symbol) tends to zero, the power distribution that minimizes expected
distortion converges to the power distribution that maximizes expected
capacity. While expected distortion can be improved by acquiring CSI at the
transmitter (CSIT) or by increasing diversity from the realization of
independent fading paths, at high SNR the performance benefit from diversity
exceeds that from CSIT, especially when b is large.
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 07:41:35 GMT"
},
{
"version": "v2",
"created": "Tue, 24 Apr 2007 00:23:10 GMT"
}
] | 2009-09-29T00:00:00 | [
[
"Ng",
"Chris T. K.",
""
],
[
"Gunduz",
"Deniz",
""
],
[
"Goldsmith",
"Andrea J.",
""
],
[
"Erkip",
"Elza",
""
]
] |
0704.2660 | Tung Lam Dao | Tung-Lam Dao, Antoine Georges, Massimo Capone | Competing superfluid and density-wave ground-states of fermionic
mixtures with mass imbalance in optical lattices | e.g.:4 pages, 3 figures | Phys. Rev. B 76, 104517 (2007) | 10.1103/PhysRevB.76.104517 | null | cond-mat.supr-con cond-mat.str-el | null | We study the effect of mass imbalance on the phase diagram of a two-component
fermionic mixture with attractive interactions in optical lattices. Using
static and dynamical mean-field theories, we show that the pure superfluid
phase is stable for all couplings when the mass imbalance is smaller than a
limiting value. For larger imbalance, phase separation between a superfluid and
a charge-density wave takes place when the coupling exceeds a critical
strength. The harmonic trap induces a spatial segregation of the two phases,
with a rapid variation of the density at the boundary.
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 07:10:25 GMT"
}
] | 2008-04-17T00:00:00 | [
[
"Dao",
"Tung-Lam",
""
],
[
"Georges",
"Antoine",
""
],
[
"Capone",
"Massimo",
""
]
] |
0704.2661 | Sergey Ananiev | Balthasar Novak, Sergey Ananiev | Application of the equal dissipation rate principle to automatic
generation of strut-and-tie models | 9 pages | Meschke G. et al. (eds.). EURO-C 2006 Computational Modelling of
Concrete Structures | null | null | math.OC | null | This work presents an extended formulation of maximal stiffness design,
within the framework of the topology optimization. The mathematical formulation
of the optimization problem is based on the postulated principle of equal
dissipation rate during inelastic deformation. This principle leads to the
enforcement of stress constraints in domains where inelastic deformation would
occur. During the transition from the continuous structure to the truss-like
one (strut-and-tie model) the dissipation rate is kept constant using the
projected gradient method. The equal dissipation rate in the resulting truss
and in the original continuous structure can be regarded as an equivalence
statement and suggests an alternative understanding of physical motivation
behind the strut-and-tie modeling. The performance of the proposed formulation
is demonstrated with the help of two examples.
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 11:09:04 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Novak",
"Balthasar",
""
],
[
"Ananiev",
"Sergey",
""
]
] |
0704.2662 | Sergey Ananiev | Sergey Ananiev, Josko Ozbolt | Plastic-damage model for concrete in principal directions | 8 pages | Li V. et al. (eds.). FraMCoS-5 Fracture Mechanics of Concrete and
Concrete Structures. 2004 | null | null | cond-mat.mtrl-sci | null | In the present paper a plastic-damage model for concrete is discussed. Based
on the fact that for isotropic materials the elastic trial stress and the
projected plastic stress states have the same eigenvec-tors, the loading
surface is formulated in the principal stress space rather than using the
invariants of stress tensor. The model assumes that the directions of
orthotropic damage coincide with principal directions of elastic predictor
stress state (motivated by coaxial rotated crack model). Due to this
assumption, the load-ing surface and the closest point projection algorithm can
still be formulated in the principal directions. The evolution of the inelastic
strain is determined using minimization principle. Damage and plastic parts of
the inelastic strain are separated using a scalar parameter, which is assumed
to be stress dependent. The paper also discusses an effective numerical
implementation. The performance of the model is demonstrated on one
illustrative example.
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 11:06:40 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Ananiev",
"Sergey",
""
],
[
"Ozbolt",
"Josko",
""
]
] |
0704.2663 | Sergey Ananiev | Josko Ozbolt, Sergey Ananiev | Scalar damage model for concrete without explicit evolution law | 8 pages | Bicanic N. et al. (eds.). EURO-C 2003 Computational Modelling of
Concrete Structures | null | null | cond-mat.mtrl-sci | null | Based on the fact that for an isotropic material model the elastic predictor
and the projected stress tensors have the same eigenvectors, it is shown that
the scalar damage can be obtained directly from the projection algorithm. This
eliminates the difficulty of a proper definition of equivalent strain which
serves as a driving force for evolution of damage in concrete. Moreover, if
eigenvectors are known it is not more nec-essary to use invariants of the
stress tensor for the formulation of loading surface. In the present model the
loading surface is represented in the polynomial form. This has two advantages:
(i) it automatically fulfils C1 continuity and (ii) plane stress formulation is
achieved by simply setting the third stress to zero. The perform-ance of the
model is illustrated on example of a mixed-mode fracture of concrete. It is
shown that for the pre-sent example the model prediction strongly depends on
the choice of the stress degradation law.
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 11:01:14 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Ozbolt",
"Josko",
""
],
[
"Ananiev",
"Sergey",
""
]
] |
0704.2664 | Werner Kirsch | Werner Kirsch | A Wegner estimate for multi-particle random Hamiltonians | null | null | null | null | math-ph math.MP | null | We prove a Wegner estimate for a large class of multiparticle Anderson
Hamiltonians on the lattice. These estimates will allow us to prove Anderson
localization for such systems. A detailed proof of localization will be given
in a subsequent paper.
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 07:55:17 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Kirsch",
"Werner",
""
]
] |
0704.2665 | Miroslaw Kozlowski | M Kozlowski, J. Marciak -Kozlowska, M.pelc | Local quantum mechanics with finite Planck mass | 6 pages | null | null | null | physics.gen-ph | null | In this paper the motion of quantum particles with initial mass m is
investigated. The quantum mechanics equation is formulated and solved. It is
shown that the wave function contains the component which is depended on the
gravitation fine structure constant
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 07:55:13 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Kozlowski",
"M",
""
],
[
"-Kozlowska",
"J. Marciak",
""
],
[
"pelc",
"M.",
""
]
] |
0704.2666 | Ilka Brunner | Marco Baumgartl, Ilka Brunner and Matthias R. Gaberdiel | D-brane superpotentials and RG flows on the quintic | 24 pages, 1 figure, v2:Typo in (3.14) corrected | JHEP0707:061,2007 | 10.1088/1126-6708/2007/07/061 | null | hep-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The behaviour of D2-branes on the quintic under complex structure
deformations is analysed by combining Landau-Ginzburg techniques with methods
from conformal field theory. It is shown that the boundary renormalisation
group flow induced by the bulk deformations is realised as a gradient flow of
the effective space time superpotential which is calculated explicitly to all
orders in the boundary coupling constant.
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 08:00:19 GMT"
},
{
"version": "v2",
"created": "Fri, 5 Mar 2010 10:21:43 GMT"
}
] | 2010-03-05T00:00:00 | [
[
"Baumgartl",
"Marco",
""
],
[
"Brunner",
"Ilka",
""
],
[
"Gaberdiel",
"Matthias R.",
""
]
] |
0704.2667 | Sergey Solodukhin N. | Thibault Damour and Sergey N. Solodukhin | Wormholes as Black Hole Foils | 13 pages, no figures, Latex | Phys.Rev.D76:024016,2007 | 10.1103/PhysRevD.76.024016 | IHES/P/07/19 | gr-qc astro-ph hep-th | null | We study to what extent wormholes can mimic the observational features of
black holes. It is surprisingly found that many features that could be thought
of as ``characteristic'' of a black hole (endowed with an event horizon) can be
closely mimicked by a globally static wormhole, having no event horizon. This
is the case for: the apparently irreversible accretion of matter down a hole,
no-hair properties, quasi-normal-mode ringing, and even the dissipative
properties of black hole horizons, such as a finite surface resistivity equal
to 377 Ohms. The only way to distinguish the two geometries on an
observationally reasonable time scale would be through the detection of
Hawking's radiation, which is, however, too weak to be of practical relevance
for astrophysical black holes. We point out the existence of an interesting
spectrum of quantum microstates trapped in the throat of a wormhole which could
be relevant for storing the information ``lost'' during a gravitational
collapse.
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 08:17:44 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Damour",
"Thibault",
""
],
[
"Solodukhin",
"Sergey N.",
""
]
] |
0704.2668 | Alex Smola J | Le Song, Alex Smola, Arthur Gretton, Karsten Borgwardt, Justin Bedo | Supervised Feature Selection via Dependence Estimation | 9 pages | null | null | null | cs.LG | null | We introduce a framework for filtering features that employs the
Hilbert-Schmidt Independence Criterion (HSIC) as a measure of dependence
between the features and the labels. The key idea is that good features should
maximise such dependence. Feature selection for various supervised learning
problems (including classification and regression) is unified under this
framework, and the solutions can be approximated using a backward-elimination
algorithm. We demonstrate the usefulness of our method on both artificial and
real world datasets.
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 08:26:29 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Song",
"Le",
""
],
[
"Smola",
"Alex",
""
],
[
"Gretton",
"Arthur",
""
],
[
"Borgwardt",
"Karsten",
""
],
[
"Bedo",
"Justin",
""
]
] |
0704.2669 | Alekber Kasumov | A.Yu. Kasumov, S. Nakamae, M. Cazayous, T. Kawasaki, Y. Okahata | Effect of premelting on conductivity of DNA-lipid films | 4 pages, 4 figures | null | null | null | cond-mat.soft | null | We have measured temperature dependent (between 20 and 80 C) electrical
conductivity and molecular structure (Raman spectroscopy) of DNA-lipid cast
film. Our findings show that the conductivity is strongly influenced by
premelting effects in the molecular structure starting near physiological
temperatures (~40 C), prior to the global DNA denaturation.
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 09:25:22 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Kasumov",
"A. Yu.",
""
],
[
"Nakamae",
"S.",
""
],
[
"Cazayous",
"M.",
""
],
[
"Kawasaki",
"T.",
""
],
[
"Okahata",
"Y.",
""
]
] |
0704.2670 | Adrian Sabin Popescu | Adrian Sabin Popescu | D.E.U.S. (Dimension Embedded in Unified Symmetry) | 247 pages, 113 figures; We merged all the DEUS model papers in a
single volume | null | null | null | gr-qc | null | An unified model of the Universe, Black Holes, particles .... and beyond.
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 08:41:41 GMT"
},
{
"version": "v2",
"created": "Mon, 7 May 2007 12:51:50 GMT"
}
] | 2009-09-29T00:00:00 | [
[
"Popescu",
"Adrian Sabin",
""
]
] |
0704.2671 | Seppo Mikkola | Seppo Mikkola, Kiyotaka Tanikawa | Correlation of macroscopic instability and Lyapunov times in the general
three-body problem | 4 pages, 7 figures. accepted for publication in MNRAS | Mon.Not.Roy.Astron.Soc.Lett.379:L21-L24,2007 | 10.1111/j.1745-3933.2007.00326.x | null | astro-ph | null | We conducted extensive numerical experiments of equal mass three-body systems
until they became disrupted. The system lifetimes, as a bound triple, and the
Lyapunov times show a correlation similarto what has been earlier obtained for
small bodies in the Solar System. Numerical integrations of several sets of
differently randomised initial conditions produced the same relationship of the
instability time and Lyapunov time. Marginal probability densities of the
various times in the three-body experiments are also discussed. Our high
accuracy numerical method for three-body orbit computations and Lyapunov time
determinations is concisely described.
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 09:02:44 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"Mikkola",
"Seppo",
""
],
[
"Tanikawa",
"Kiyotaka",
""
]
] |
0704.2672 | Minzu Wang | M.-Z. Wang, Y.-J. Lee, et al (for the Belle Collaboration) | Study of B+ to p Lambdabar gamma, p Lambdabar pi0 and B0 to p Lambdabar
pi- | 12 pages, 5 figures (11 figure files), PRD published version | Phys.Rev.D76:052004,2007 | 10.1103/PhysRevD.76.052004 | Belle Preprint 2007-19, KEK Preprint 2007-6 | hep-ex | null | We study the charmless baryonic three-body decays of B mesons: B+ to p
Lambdabar gamma, B+ to p Lambdabar pi0 and B0 to p Lambdabar pi-. The partial
branching fractions as a function of the baryon-antibaryon mass and the polar
angle distributions of the proton in the baryon-antibaryon system are
presented. This study includes the first observation of B+ to p Lambdabar pi0,
which is measured to have a branching fraction of (3.00^{+0.61}_{-0.53}\pm
0.33) times 10^{-6}. We also set upper limits on branching fractions of the
two-body decays B0 to p Sigmabar^{*-}, B0 to Delta^0 Lambdabar, B+ to p
Sigmabar^{*0}, and B+ to Delta^+ Lambdabar at the 90% confidence level. These
results are obtained from a 414fb^{-1} data sample collected near the
Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+
e- collider.
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 09:06:38 GMT"
},
{
"version": "v2",
"created": "Mon, 23 Apr 2007 02:53:04 GMT"
},
{
"version": "v3",
"created": "Tue, 24 Apr 2007 02:06:11 GMT"
},
{
"version": "v4",
"created": "Wed, 26 Sep 2007 10:07:48 GMT"
}
] | 2019-08-12T00:00:00 | [
[
"Wang",
"M. -Z.",
""
],
[
"Lee",
"Y. -J.",
""
]
] |
0704.2673 | Leonid Glozman | L. Ya. Glozman (Univ. Graz), A. V. Nefediev (ITEP, Moscow) | Chiral symmetry and the string description of excited hadrons | RevTeX, 5 pages, a few footnotes have been added, to appear in PRD | Phys.Rev.D76:096004,2007 | 10.1103/PhysRevD.76.096004 | null | hep-ph hep-lat hep-th nucl-th | null | A large symmetry group is perhaps experimentally observed in excited hadrons
which includes the chiral group U(2)_L x U(2)_R as a subgroup. To possess this
large symmetry a dynamical model for excited hadrons, presumably a string
model, should explain formation of chiral multiplets and, at the same time,
predict coinciding slopes of the angular and radial Regge trajectories. This is
possible only if both the dynamics of the string and the chirality of the
quarks at the ends of the string are considered together. We construct a
model-independent unitary transformation from the relativistic chiral basis to
the ^{2S+1}L_J basis, commonly used in hadronic phenomenology as well as in the
string models, and demonstrate that a hadron belonging to the given chiral
representation is a fixed superposition of the basis vectors with different L's
and S's. Thus the description of highly excited hadron in terms of a fixed L is
not compatible with chiral symmetry and has to be disregarded in favour of the
description in terms of the total hadron spin J. Therefore, dynamics of the
string must deliver the principal quantum number ~n+J, in order chiral
multiplets with different spins to become degenerate, as required by the large
symmetry group.
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 10:07:22 GMT"
},
{
"version": "v2",
"created": "Thu, 4 Oct 2007 15:56:55 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Glozman",
"L. Ya.",
"",
"Univ. Graz"
],
[
"Nefediev",
"A. V.",
"",
"ITEP, Moscow"
]
] |
0704.2674 | Dikanaina Harrivel | Dikanaina Harrivel and Fr\'ederic H\'elein | First integrals for non linear hyperbolic equations | 38 pages, 1 figure, v2: some sign conventions have been changed, some
minor corrections has been added | null | null | null | math.AP | null | Given a solution of a nonlinear wave equation on the flat space-time (with a
real analytic nonlinearity), we relate its Cauchy data at two different times
by nonlinear representation formulas in terms of asymptotic series. We first
show how to construct formally these series by mean of generating functions
based on an algebraic framework inspired by the construction of Fock spaces in
quantum field theory. Then we build an analytic setting in which all these
constructions really make sense and give rise to convergent series.
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 10:06:56 GMT"
},
{
"version": "v2",
"created": "Wed, 27 Feb 2008 17:21:40 GMT"
}
] | 2008-02-27T00:00:00 | [
[
"Harrivel",
"Dikanaina",
""
],
[
"Hélein",
"Fréderic",
""
]
] |
0704.2675 | Sergey Gevorkyan | S.R.Gevorkyan, A.N.Sissakian, A.V.Tarasov, H.T.Torosyan,
O.O.Voskresenskaya | The isospin symmetry breaking effects in $K_{e4}$ decays | null | Phys.Atom.Nucl.73:961,2010 | 10.1134/S1063778810060098 | null | hep-ph | null | The Fermi-Watson theorem is generalized to the case of two coupled channels
with different masses and applied to final state interaction in $K_{e4}$
decays. The impact of considered effect on the phase of the $\pi\pi$ scattering
is estimated and shown that it can be crucial for scattering lengths extraction
from experimental data on $K_{e4}$ decays.
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 09:22:38 GMT"
},
{
"version": "v2",
"created": "Fri, 16 May 2008 19:19:42 GMT"
}
] | 2011-04-07T00:00:00 | [
[
"Gevorkyan",
"S. R.",
""
],
[
"Sissakian",
"A. N.",
""
],
[
"Tarasov",
"A. V.",
""
],
[
"Torosyan",
"H. T.",
""
],
[
"Voskresenskaya",
"O. O.",
""
]
] |
0704.2676 | Eli Ben-Haim | E. Ben-Haim (LPNHE) | CP Violation Studies at Tevatron | 4 pages. Talk given at BEACH 2006, Lancaster, England | Nucl.Phys.Proc.Suppl.167:120-123,2007 | 10.1016/j.nuclphysbps.2006.12.094 | null | hep-ex | null | We present an overview of a few recent results related to CP-violation from
the Tevatron. First, we discuss a measurement of the dimuon charge asymmetry
from D{\O}that extracts the CP-violation parameter of $\Bo$ mixing and decay.
This is followed by the CDF measurement of the CP-violating asymmetry in
$\bdkpi$ decays. Finally we give the CDF result on the ratio $R = \frac{BR(B
\to D^0 K)}{BR(B \to D^0 \pi)}$
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 09:25:05 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Ben-Haim",
"E.",
"",
"LPNHE"
]
] |
0704.2677 | Jitesh Bhatt | Jitesh R. Bhatt, Prasanta K. Panigrahi and Manan Vyas | Entanglement induced Sub-Planck structures | 6 pages 2 figures (revised version include more quantitative
discussion) | Phys. Rev. A78, 034101, 2008 | 10.1103/PhysRevA.78.034101 | null | quant-ph | null | We study Wigner function of a system describing entanglement of two
cat-states. Quantum interferece arising due to entanglement is shown to produce
sub-Planck structures in the phase-space plots of the Wigner function. Origin
of these structures in our case depends on entanglement unlike those in Zurek
\cite{Zurek}. It is argued that the entangled cat-states are better suited for
carrying out precision measurements.
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 09:35:21 GMT"
},
{
"version": "v2",
"created": "Fri, 31 Aug 2007 07:22:03 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Bhatt",
"Jitesh R.",
""
],
[
"Panigrahi",
"Prasanta K.",
""
],
[
"Vyas",
"Manan",
""
]
] |
0704.2678 | Andrea Morandi | A. Morandi, S. Ettori, L. Moscardini | X-ray and Sunyaev-Zel'dovich scaling relations in galaxy clusters | MNRAS in press - Minor revision to match published version | Mon.Not.Roy.Astron.Soc.379:518-534,2007 | 10.1111/j.1365-2966.2007.11882.x | null | astro-ph | null | [Abridged] We present an analysis of the scaling relations between X-ray
properties and Sunyaev-Zel'dovich (SZ) parameters for a sample of 24 X-ray
luminous galaxy clusters observed with Chandra and with measured SZ effect.
These objects are in the redshift range 0.14--0.82 and have X-ray bolometric
luminosity L>10^45 erg/s. We perform a spatially resolved spectral analysis and
recover the density, temperature and pressure profiles of the ICM, just relying
on the spherical symmetry of the cluster and the hydrostatic equilibrium
hypothesis. We observe that the correlations among X-ray quantities only are in
agreement with previous results obtained for samples of high-z X-ray luminous
galaxy clusters. On the relations involving SZ quantities, we obtain that they
correlate with the gas temperature with a logarithmic slope significantly
larger than the predicted value from the self-similar model. The measured
scatter indicates, however, that the central Compton parameter y_0 is a proxy
of the gas temperature at the same level of other X-ray quantities like
luminosity. Our results on the X-ray and SZ scaling relations show a tension
between the quantities more related to the global energy of the system (e.g.
gas temperature, gravitating mass) and the indicators of the structure of the
ICM (e.g. gas density profile, central Compton parameter y_0), showing the most
significant deviations from the values of the slope predicted from the
self-similar model in the L-T, L-M_{tot}, M_{gas}-T, y_0-T relations. When the
slope is fixed to the self-similar value, these relations consistently show a
negative evolution suggesting a scenario in which the ICM at higher redshift
has lower both X-ray luminosity and pressure in the central regions than the
expectations from self-similar model.
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 10:07:42 GMT"
},
{
"version": "v2",
"created": "Tue, 10 Jul 2007 11:47:10 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"Morandi",
"A.",
""
],
[
"Ettori",
"S.",
""
],
[
"Moscardini",
"L.",
""
]
] |
0704.2679 | Prasanta K. Panigrahi | N. Gurappa, Pankaj K. Jha and Prasanta K. Panigrahi | On the Applications of a New Technique to Solve Linear Differential
Equations, with and without Source | This is a contribution to the Vadim Kuznetsov Memorial Issue on
Integrable Systems and Related Topics, published in SIGMA (Symmetry,
Integrability and Geometry: Methods and Applications) at
http://www.emis.de/journals/SIGMA/ | SIGMA 3 (2007), 057, 6 pages | 10.3842/SIGMA.2007.057 | null | math-ph math.MP nlin.SI | null | A general method for solving linear differential equations of arbitrary
order, is used to arrive at new representations for the solutions of the known
differential equations, both without and with a source term. A new
quasi-solvable potential has also been constructed taking recourse to the above
method.
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 10:13:24 GMT"
}
] | 2008-04-24T00:00:00 | [
[
"Gurappa",
"N.",
""
],
[
"Jha",
"Pankaj K.",
""
],
[
"Panigrahi",
"Prasanta K.",
""
]
] |
0704.2680 | Tobias Koch | Tobias Koch, Amos Lapidoth and Paul P. Sotiriadis | A Channel that Heats Up | to appear in Proceedings of the 2007 IEEE International Symposium on
Information Theory (ISIT), Nice, France | null | null | null | cs.IT math.IT | null | Motivated by on-chip communication, a channel model is proposed where the
variance of the additive noise depends on the weighted sum of the past channel
input powers. For this channel, an expression for the capacity per unit cost is
derived, and it is shown that the expression holds also in the presence of
feedback.
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 10:26:53 GMT"
}
] | 2007-07-13T00:00:00 | [
[
"Koch",
"Tobias",
""
],
[
"Lapidoth",
"Amos",
""
],
[
"Sotiriadis",
"Paul P.",
""
]
] |
0704.2681 | Amelia Bayo M | A. Bayo, D. Barrado y Navascues, M. Morales-Calderon, E. Solano, C.
Rodrigo, R. Gutierrez, F. Allard | Cool objects: From SED fitting to age estimation | Contribution to Astronomical Spectroscopy and the Virtual Observatory | null | null | null | astro-ph | null | The physical properties of almost any kind of astronomical object can be
derived by fitting synthetic spectra or photometry extracted from theoretical
models to observational data. This process usually involves working with
multiwavelength data, which is one of the cornerstones of the VO philosophy.
From this kind of studies, when combining with theoretical isochrones one can
even estimate ages. We present here the results obtained from a code designed
to perform chi^2 tests to both spectroscopic models (or the associated
synthetic photometry) and combinations of blackbodies (including modified
blackbodies). Some steps in this process can already be done in a VO
environment, and the rest are in the process of development. We must note that
this kind of studies in star forming regions, clusters, etc. produce a huge
amount of data, very tedious to analyze using the traditional methodology. This
make them excellent examples where to apply the VO capabilities.
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 10:27:13 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Bayo",
"A.",
""
],
[
"Navascues",
"D. Barrado y",
""
],
[
"Morales-Calderon",
"M.",
""
],
[
"Solano",
"E.",
""
],
[
"Rodrigo",
"C.",
""
],
[
"Gutierrez",
"R.",
""
],
[
"Allard",
"F.",
""
]
] |
0704.2682 | Alexander Gruneis | A. Gruneis, C. Attaccalite, T. Pichler, V. Zabolotnyy, H. Shiozawa,
S.L. Molodtsov, D. Inosov, A. Koitzsch, M. Knupfer, J. Schiessling, R.
Follath, R. Weber, P. Rudolf, L. Wirtz, A. Rubio | Electron-electron correlation in graphite | null | null | null | null | cond-mat.mtrl-sci cond-mat.str-el | null | The full three dimensional dispersion of the pi-bands, Fermi velocities and
effective masses are measured with angle resolved photoemission spectroscopy
and compared to first-principles calculations. The band structure by
density-functional theory strongly underestimates the slope of the bands and
the trigonal warping effect. Including electron-electron calculation on the
level of the GW approximation, however, yields remarkable agreement in the
vicinity of the Fermi level. This demonstrates the breakdown of the independent
electron picture in semi-metallic graphite and points towards a pronounced role
of electron correlation for the interpretation of transport experiments and
double-resonant Raman scattering for a wide range of carbon based materials.
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 15:13:20 GMT"
},
{
"version": "v2",
"created": "Fri, 19 Oct 2007 17:33:44 GMT"
}
] | 2011-11-09T00:00:00 | [
[
"Gruneis",
"A.",
""
],
[
"Attaccalite",
"C.",
""
],
[
"Pichler",
"T.",
""
],
[
"Zabolotnyy",
"V.",
""
],
[
"Shiozawa",
"H.",
""
],
[
"Molodtsov",
"S. L.",
""
],
[
"Inosov",
"D.",
""
],
[
"Koitzsch",
"A.",
""
],
[
"Knupfer",
"M.",
""
],
[
"Schiessling",
"J.",
""
],
[
"Follath",
"R.",
""
],
[
"Weber",
"R.",
""
],
[
"Rudolf",
"P.",
""
],
[
"Wirtz",
"L.",
""
],
[
"Rubio",
"A.",
""
]
] |
0704.2683 | Hans-Thomas Elze | Hans-Thomas Elze | A relativistic gauge theory of nonlinear quantum mechanics and Newtonian
gravity | 16 pages; to appear in Int. J. Theor. Phys. (2007) | Int.J.Theor.Phys.47:455-467,2008 | 10.1007/s10773-007-9471-6 | null | gr-qc hep-th quant-ph | null | A new kind of gauge theory is introduced, where the minimal coupling and
corresponding covariant derivatives are defined in the space of functions
pertaining to the functional Schroedinger picture of a given field theory.
While, for simplicity, we study the example of a U(1) symmetry, this kind of
gauge theory can accommodate other symmetries as well. We consider the
resulting relativistic nonlinear extension of quantum mechanics and show that
it incorporates gravity in the (0+1)-dimensional limit, similar to recently
studied Schroedinger-Newton equations. Gravity is encoded here into a universal
nonlinear extension of quantum theory. A probabilistic interpretation (Born's
rule) holds, provided the underlying model is scale free.
Keywords: nonlinear functional Schroedinger equation, gauge symmetry,
Newtonian gravity.
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 10:34:50 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Elze",
"Hans-Thomas",
""
]
] |
0704.2684 | Thomas Kernreiter | Karl Hohenwarter-Sodek, Thomas Kernreiter | Effects of Lepton Flavour Violation on Chargino Production at the Linear
Collider | 11pp; final version for JHEP | JHEP 0706:071,2007 | 10.1088/1126-6708/2007/06/071 | null | hep-ph | null | We study the effects of lepton flavour violation (LFV) on the production
processes e+e- --> \chi+_i \chi-_j at a linear collider with longitudinal e+
and e- beam polarizations. In the case of LFV the sneutrino mass eigenstates
have no definite flavour, therefore, in the t-channel more than one sneutrino
mass eigenstate can contribute to the chargino production cross sections. Our
framework is the Minimal Supersymmetric Standard Model (MSSM) including LFV
terms. We show that in spite of the restrictions on the LFV parameters due to
the current limits on rare lepton decays, the cross section \sigma(e+e- -->
\chi+_1 \chi-_1) can change by a factor of 2 or more when varying the LFV
mixing angles. We point out that even if the present bound on BR(tau- --> e-
gamma) improves by a factor of thousand the influence of LFV on the chargino
production cross section can be significant. These results could have an
important impact on the strategies for determining the underlying model
parameters at the linear collider.
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 10:43:50 GMT"
},
{
"version": "v2",
"created": "Mon, 25 Jun 2007 09:27:49 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Hohenwarter-Sodek",
"Karl",
""
],
[
"Kernreiter",
"Thomas",
""
]
] |
0704.2685 | Claudio Codella | S. Cabrit, C. Codella, F. Gueth, B. Nisini, A. Gusdorf, C. Dougados,
F. Bacciotti | PdBI sub-arcsecond study of the SiO microjet in HH212 - Origin and
collimation of Class 0 jets | null | null | 10.1051/0004-6361:20077387 | null | astro-ph | null | The bipolar HH 212 outflow has been mapped in SiO using the extended
configuration of the Plateau de Bure Interferometer (PdBI), revealing a highly
collimated SiO jet closely associated with the H2 jet component. We study at
unprecedented resolution (0.34" across the jet axis) the properties of the
innermost SiO ``microjet'' within 1000 AU of this young Class 0 source, to
compare it with atomic microjets from more evolved sources and to constrain its
origin. The SiO channel maps are used to investigate the microjet collimation
and velocity structure. A large velocity gradient analysis is applied to SiO
(2-1), (5-4) and (8-7) data from the PdBI and the Submillimeter Array to
constrain the SiO opacity and abundance. The HH212 Class 0 microjet shows
striking similarities in collimation and energetic budget with atomic microjets
from T Tauri sources. Furthermore, the SiO lines appear optically thick, unlike
what is generally assumed. We infer T(kin) ~ 50-500 K and an SiO/H2 abundance
greater than 4 10(-8)-6 10(-5) for n(H2) = 10(7)-10(5) cm(-3), i.e. 0.05-90% of
the elemental silicon. This similar jet width, regardless of the presence of a
dense envelope, definitely rules out jet collimation by external pressure, and
favors a common MHD self-collimation (and possibly acceleration) process at all
stages of star formation. We propose that the more abundant SiO in Class 0 jets
could mainly result from rapid (less than 25 yrs) molecular synthesis at high
jet densities.
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 10:59:11 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Cabrit",
"S.",
""
],
[
"Codella",
"C.",
""
],
[
"Gueth",
"F.",
""
],
[
"Nisini",
"B.",
""
],
[
"Gusdorf",
"A.",
""
],
[
"Dougados",
"C.",
""
],
[
"Bacciotti",
"F.",
""
]
] |
0704.2686 | Vasiliy Kharchenko | E.D.Belokolos, V.O.Kharchenko | Self-organization processes in laser system with nonlinear absorber and
external force influence | 9 pages, 13 figures | null | null | null | nlin.AO | null | We discuss mechanisms of self-organization processes in two-level solid-state
class-B laser system. The model is considered under assumptions of influence of
nonlinear absorber and external force, separately. It was found that
self-organization occurs through the Hopf bifurcation and results to a stable
pulse radiation. Analysis is performed according to the Floquet exponent
investigation. It was found that influence of the nonlinear absorber extends
the domain of control parameters that manage a stable periodic radiation
processes. An external force suppresses self-organization processes. A combined
influence of both external force and nonlinear absorber results to more
complicated picture of self-organization with two reentrant Hopf bifurcations.
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 10:59:57 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Belokolos",
"E. D.",
""
],
[
"Kharchenko",
"V. O.",
""
]
] |
0704.2687 | Marius Buliga | Marius Buliga | Equilibrium and absolute minimal states of Mumford-Shah functionals and
brittle fracture propagation | larger version | null | null | null | math.AP cond-mat.mtrl-sci | null | By a combination of geometrical and configurational analysis we study the
properties of absolute minimal and equilibrium states of general Mumford-Shah
functionals, with applications to models of quasistatic brittle fracture
propagation. The main results concern the mathematical relations between
physical quantities as energy release rate and energy concentration for 3D
cracks with complex shapes, seen as outer measures living on the crack edge.
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 11:08:49 GMT"
},
{
"version": "v2",
"created": "Fri, 14 Mar 2008 11:51:51 GMT"
}
] | 2008-03-14T00:00:00 | [
[
"Buliga",
"Marius",
""
]
] |
0704.2688 | Cheryl Praeger | Cheryl E. Praeger and Shenglin Zhou | Classification of line-transitive point-imprimitive linear spaces with
line size at most 12 | 16 pages | null | null | null | math.CO | null | In this paper we complete a classification of finite linear spaces $\cS$ with
line size at most 12 admitting a line-transitive point-imprimitive subgroup of
automorphisms. The examples are the Desarguesian projective planes of orders
$4,7, 9$ and 11, two designs on 91 points with line size 6, and 467 designs on
729 points with line size 8.
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 11:33:10 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Praeger",
"Cheryl E.",
""
],
[
"Zhou",
"Shenglin",
""
]
] |
0704.2689 | Jorick S. Vink | Jorick S. Vink and Rubina Kotak | Mass loss from Luminous Blue Variables and Quasi-Periodic Modulations of
Radio Supernovae | 6 pages, 5 figs, To appear in: "Circumstellar Media and Late Stages
of Massive Stellar Evolution" | null | null | null | astro-ph | null | Massive stars, supernovae (SNe), and long-duration gamma-ray bursts (GRBs)
have a huge impact on their environment. Despite their importance, a
comprehensive knowledge of which massive stars produce which SN/GRB is hitherto
lacking. We present a brief overview about our knowledge of mass loss in the
Hertzsprung-Russell Diagram (HRD) covering evolutionary phases of the OB main
sequence, the unstable Luminous Blue Variable (LBV) stage, and the Wolf-Rayet
(WR) phase. Despite the fact that metals produced by ``self-enrichment'' in WR
atmospheres exceed the initial -- host galaxy -- metallicity, by orders of
magnitude, a particularly strong dependence of the mass-loss rate on the
initial metallicity is found for WR stars at sub-solar metallicities (1/10 --
1/100 solar). This provides a significant boost to the collapsar model for
GRBs, as it may present a viable mechanism to prevent the loss of angular
momentum by stellar winds at low metallicity, whilst strong Galactic WR winds
may inhibit GRBs occurring at solar metallicities. Furthermore, we discuss
recently reported quasi-sinusoidal modulations in the radio lightcurves of SNe
2001ig and 2003bg. We show that both the sinusoidal behaviour and the
recurrence timescale of these modulations are consistent with the predicted
mass-loss behaviour of LBVs, and we suggest LBVs may be the progenitors of some
core-collapse SNe.
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 11:41:54 GMT"
}
] | 2019-08-19T00:00:00 | [
[
"Vink",
"Jorick S.",
""
],
[
"Kotak",
"Rubina",
""
]
] |
0704.2690 | Jorick S. Vink | Jorick S. Vink (Armagh Observatory) | Constraining GRB progenitor models by probing Wolf-Rayet wind geometries
in the Large Magellanic Cloud | Accepted for A&A | null | 10.1051/0004-6361:20077302 | null | astro-ph | null | The favoured progenitors of long-duration gamma-ray bursts (GRBs) are rapidly
rotating Wolf-Rayet (WR) stars. However, most Galactic WR stars are slow
rotators, as stellar winds are thought to remove angular momentum. This poses a
challenge to the collapsar model. Recent observations indicate that GRBs occur
predominately in low metallicity (Z) environments, which may resolve the
problem: lower Z leads to less mass loss, which may inhibit angular momentum
removal, allowing WR stars to remain rotating rapidly until collapse. We wish
to determine whether low Z WR stars rotate on average more rapidly than
Galactic WR stars, and perform a Very Large Telescope (VLT) linear
spectropolarimetry survey of WR stars in the low Z environment of the Large
Magellanic Cloud (LMC) and compare our results with the Galactic sample. We
find that only 2 out of 13 (i.e. 15%) of LMC WR stars show line polarization
effects, compared to a similarly low fraction of ~15-20% for Galactic WR stars.
The low incidence of line polarization effects in LMC WR stars suggests that
the threshold metallicity where significant differences in WR rotational
properties occur is below that of the LMC (Z ~ 0.5 Zsun), possibly constraining
GRB progenitor channels to this upper metallicity.
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 11:46:56 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Vink",
"Jorick S.",
"",
"Armagh Observatory"
]
] |
0704.2691 | Gijsbert Rispens | Gijsbert Rispens and Beatriz Noheda | Thin Lead Titanate films grown by Molecular Beam Epitaxy | Proceedings of the Rank-Prize symposium on Opto-electronics held in
Grasmere (UK), September 2006. To appear in "Ferroelectrics" | null | null | null | cond-mat.mtrl-sci | null | The growth of atomically-flat thin films of ferroelectric PbTiO3 on SrTiO3
substrates, using molecular beam epitaxy, is reported. The main issue in the
growth of these materials is the high volatility of lead. This can be largely
overcome by using PbO, instead of Pb, as a source and by using atomic oxygen
during growth. The continuous decrease of the out-of-plane lattice parameter
with increasing temperature in the investigated range, indicates that PbTiO3 is
still ferroelectric at the growth temperature (Tg= 600oC), which agrees with
the theoretical prediction of TC= 765oC (compared to TCbulk= 490oC) for the
present mismatch strain values.
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 17:49:53 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Rispens",
"Gijsbert",
""
],
[
"Noheda",
"Beatriz",
""
]
] |
0704.2692 | Serge Troubetzkoy | Cheng-Hung Chang, Tyll Krueger, Roman Schubert, Serge Troubetzkoy
(CPT, FRUMAM, IML) | Quantisations of piecewise affine maps on the torus and their quantum
limits | null | null | 10.1007/s00220-008-0557-7 | null | math.DS math-ph math.MP quant-ph | null | For general quantum systems the semiclassical behaviour of eigenfunctions in
relation to the ergodic properties of the underlying classical system is quite
difficult to understand. The Wignerfunctions of eigenstates converge weakly to
invariant measures of the classical system, the so called quantum limits, and
one would like to understand which invariant measures can occur that way,
thereby classifying the semiclassical behaviour of eigenfunctions. We introduce
a class of maps on the torus for whose quantisations we can understand the set
of quantum limits in great detail. In particular we can construct examples of
ergodic maps which have singular ergodic measures as quantum limits, and
examples of non-ergodic maps where arbitrary convex combinations of absolutely
continuous ergodic measures can occur as quantum limits. The maps we quantise
are obtained by cutting and stacking.
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 11:55:46 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Chang",
"Cheng-Hung",
"",
"CPT, FRUMAM, IML"
],
[
"Krueger",
"Tyll",
"",
"CPT, FRUMAM, IML"
],
[
"Schubert",
"Roman",
"",
"CPT, FRUMAM, IML"
],
[
"Troubetzkoy",
"Serge",
"",
"CPT, FRUMAM, IML"
]
] |
0704.2693 | Horst Balthasar | H. Balthasar, O. von der L\"uhe, F. Kneer, J. Staude, R. Volkmer, T.
Berkefeld, P. Caligari, M. Collados, C. Halbgewachs, F. Heidecke, A. Hofmann,
M. Klvana, H. Nicklas, E. Popow, K. Puschmann, W. Schmidt, M. Sobotka, D.
Soltau, K. Strassmeier, and A. Wittmann | GREGOR: the New German Solar Telescope | in press, "Physics of Chromospheric Plasmas" (Coimbra), ASP 368, 605
(2007) | null | null | null | astro-ph | null | GREGOR is a new open solar telescope with an aperture of 1.5m. It replaces
the former 45-cm Gregory Coude telescope on the Canary island Tenerife. The
optical concept is that of a double Gregory system. The main and the elliptical
mirrors are made from a silicon-carbide material with high thermal
conductivity. This is important to keep the mirrors on the ambient temperature
avoiding local turbulence. GREGOR will be equipped with an adaptive optics
system. The new telescope will be ready for operation in 2008. Post-focus
instruments in the first stage will be a spectrograph for polarimetry in the
near infrared and a 2-dimensional spectrometer based on Fabry-Perot
interferometers for the visible.
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 12:01:35 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Balthasar",
"H.",
""
],
[
"von der Lühe",
"O.",
""
],
[
"Kneer",
"F.",
""
],
[
"Staude",
"J.",
""
],
[
"Volkmer",
"R.",
""
],
[
"Berkefeld",
"T.",
""
],
[
"Caligari",
"P.",
""
],
[
"Collados",
"M.",
""
],
[
"Halbgewachs",
"C.",
""
],
[
"Heidecke",
"F.",
""
],
[
"Hofmann",
"A.",
""
],
[
"Klvana",
"M.",
""
],
[
"Nicklas",
"H.",
""
],
[
"Popow",
"E.",
""
],
[
"Puschmann",
"K.",
""
],
[
"Schmidt",
"W.",
""
],
[
"Sobotka",
"M.",
""
],
[
"Soltau",
"D.",
""
],
[
"Strassmeier",
"K.",
""
],
[
"Wittmann",
"A.",
""
]
] |
0704.2694 | Yana Volkovich | Yana Volkovich, Nelly Litvak and Debora Donato | Determining factors behind the PageRank log-log plot | null | LNCS, Algorithms and Models for the Web-Graph,5th International
Workshop, WAW 2007, San Diego, CA, USA, December 11-12, 2007. Proceedings | 10.1007/978-3-540-77004-6_9 | null | math.PR | null | We study the relation between PageRank and other parameters of information
networks such as in-degree, out-degree, and the fraction of dangling nodes. We
model this relation through a stochastic equation inspired by the original
definition of PageRank. Further, we use the theory of regular variation to
prove that PageRank and in-degree follow power laws with the same exponent. The
difference between these two power laws is in a multiple coefficient, which
depends mainly on the fraction of dangling nodes, average in-degree, the power
law exponent, and damping factor. The out-degree distribution has a minor
effect, which we explicitly quantify. Our theoretical predictions show a good
agreement with experimental data on three different samples of the Web.
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 18:06:02 GMT"
}
] | 2008-04-03T00:00:00 | [
[
"Volkovich",
"Yana",
""
],
[
"Litvak",
"Nelly",
""
],
[
"Donato",
"Debora",
""
]
] |
0704.2695 | Fa Min Liu | Hong-Jian Feng, Fa-Min Liu | Electronic structure of barium titanate : an abinitio DFT study | 7 pages, 12 figures. Submitted to Physica B | null | null | null | cond-mat.mtrl-sci cond-mat.str-el | null | First principle calculations were performed to study the ground state
electronic properties of Barium titanate within the density functional theory
(DFT). In our DFT computations, we used Vosko-Wilk-Nusair correlation energy
functional and generalized gradient approximation (GGA) exchange and
correlation energy functional as suggested by Perdew and Wang (PWGGA). The band
structure, total density of states (DOS) and partial DOS have been
systematically conducted to investigate the electronic configuration of this
prototype ferroelectric perovskits compound. The band gap was 1.92 eV within
our approach, and the quasi-flat band at -17 eV and -10 eV were attributed to
the O 2s and Ba 5p states respectively, which was in good agreement with the
corresponding total DOS and partial DOS. From the DOS investigation, it can be
seen that the Ti eg state intended to interact with the oxygen octahedral
orbitals to form the p-d hybridization. Moreover the strong p-d overlap and
bonding can be observed in the electronic density redistribution along the
different crystalline planes with respect to the corresponding space group, and
the electronic isodense have been shown along the (001), (100), (110) and (111)
crystal planes. From these electronic density maps, the strong bonding between
Ti and O atoms can even be observed in the (111) crystalline plane.
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 12:21:05 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Feng",
"Hong-Jian",
""
],
[
"Liu",
"Fa-Min",
""
]
] |
0704.2696 | So Matsuura | Poul H. Damgaard and So Matsuura | Classification of Supersymmetric Lattice Gauge Theories by Orbifolding | 30 pages, 8 figures, LaTeX2e, typos corrected, added discussion about
supersymmetry transformations | JHEP0707:051,2007 | 10.1088/1126-6708/2007/07/051 | null | hep-lat hep-th | null | We provide a general classification of supersymmetric lattice gauge theories
that can be obtained from orbifolding of theories with four and eight
supercharges. We impose at least one preserved supercharge on the lattice and
Lorentz invariance in the naive continuum limit. Starting with four
supercharges, we obtain one two-dimensional lattice gauge theory, identical to
the one already given in the literature. Starting with eight supercharges, we
obtain a unique three-dimensional lattice gauge theory and infinitely many
two-dimensional lattice theories. They can be classified according to seven
distinct groups, five of which have two preserved supercharges while the others
have only one.
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 12:21:16 GMT"
},
{
"version": "v2",
"created": "Wed, 27 Jun 2007 11:15:41 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Damgaard",
"Poul H.",
""
],
[
"Matsuura",
"So",
""
]
] |
0704.2697 | Andrzej Sitarz | Andrzej Sitarz | On matrix type corings, algebra coverings and Cech cohomology | null | International Journal of Geometric Methods in Modern Physics, Vol.
4, No. 7 (2007) 1099 -- 1105 | 10.1142/S0219887807002454 | null | math.RA math-ph math.MP | null | We investigate the a matrix-type coring associated to a complete covering of
an algebra, its Amitsur complex and propose a definition for the related Cech
cohomology relative to the covering.
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 12:31:33 GMT"
},
{
"version": "v2",
"created": "Fri, 14 Mar 2008 19:08:50 GMT"
}
] | 2015-05-13T00:00:00 | [
[
"Sitarz",
"Andrzej",
""
]
] |
0704.2698 | Volker Beckmann | Volker Beckmann (1), Neil Gehrels (2) and Jack Tueller (2) ((1)
INTEGRAL Science Data Centre, (2) NASA/GSFC) | The 1 keV to 200 keV X-ray Spectrum of NGC 2992 and NGC 3081 | 8 pages, 4 figures, accepted for publication in ApJ | Astrophys.J.666:122-127,2007 | 10.1086/519486 | null | astro-ph | null | The Seyfert 2 galaxies NGC 2992 and NGC 3081 have been observed by INTEGRAL
and Swift. We report about the results and the comparison of the spectrum above
10 keV based on INTEGRAL IBIS/ISGRI, Swift/BAT, and BeppoSAX/PDS. A spectrum
can be extracted in the X-ray energy band ranging from 1 keV up to 200 keV.
Although NGC 2992 shows a complex spectrum below 10 keV, the hard tail observed
by various missions exhibits a slope with photon index = 2, independent on the
flux level during the observation. No cut-off is detectable up to the detection
limit around 200 keV. In addition, NGC 3081 is detected in the INTEGRAL and
Swift observation and also shows an unbroken Gamma = 1.8 spectrum up to 150
keV. These two Seyfert galaxies give further evidence that a high-energy
cut-off in the hard X-ray spectra is often located at energies E_C >> 100 keV.
In NGC 2992 a constant spectral shape is observed over a hard X-ray luminosity
variation by a factor of 11. This might indicate that the physical conditions
of the emitting hot plasma are constant, while the amount of plasma varies, due
to long-term flaring activity.
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 12:32:49 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"Beckmann",
"Volker",
""
],
[
"Gehrels",
"Neil",
""
],
[
"Tueller",
"Jack",
""
]
] |
0704.2699 | Guido Caldarelli | David Gfeller (1), Paolo De Los Rios (1), David Morton de Lachapelle
(1), Guido Caldarelli (2,3), Francesco Rao (3) ((1) EPFL Lausanne
Switzerland, (2) SMC CNR-INFM Rome Italy, (3) Centro Fermi Rome Italy) | Uncovering the topology of configuration space networks | 6 figures | null | 10.1103/PhysRevE.76.026113 | null | cond-mat.stat-mech cond-mat.dis-nn | null | The configuration space network (CSN) of a dynamical system is an effective
approach to represent the ensemble of configurations sampled during a
simulation and their dynamic connectivity. To elucidate the connection between
the CSN topology and the underlying free-energy landscape governing the system
dynamics and thermodynamics, an analytical soluti on is provided to explain the
heavy tail of the degree distribution, neighbor co nnectivity and clustering
coefficient. This derivation allows to understand the universal CSN network
topology observed in systems ranging from a simple quadratic well to the native
state of the beta3s peptide and a 2D lattice heteropolymer. Moreover CSN are
shown to fall in the general class of complex networks describe d by the
fitness model.
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 12:34:53 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Gfeller",
"David",
""
],
[
"Rios",
"Paolo De Los",
""
],
[
"de Lachapelle",
"David Morton",
""
],
[
"Caldarelli",
"Guido",
""
],
[
"Rao",
"Francesco",
""
]
] |
0704.2700 | Ivan Degtyarenko Mr. | Ivan Degtyarenko, Karl J. Jalkanen, Andrey A. Gurtovenko and Risto M.
Nieminen | The aqueous and crystalline forms of L-alanine zwitterion | preprint of 22 pages, 7 figures, and 2 tables | null | null | null | physics.bio-ph physics.chem-ph physics.comp-ph | null | The structural properties of L-alanine amino acid in aqueous solution and in
crystalline phase have been studied by means of density-functional
electronic-structure and molecular dynamics simulations. The solvated
zwitterionic structure of L-alanine (+NH3-C2H4-COO-) was systematically
compared to the structure of its zwitterionic crystalline analogue acquired
from both computer simulations and experiments. It turns out that the
structural properties of an alanine molecule in aqueous solution can differ
significantly from those in crystalline phase, these differences being mainly
attributed to hydrogen bonding interactions. In particular, we found that the
largest difference between the two alanine forms can be seen for the
orientation and bond lengths of the carboxylate (COO-) group: in aqueous
solution the C-O bond lengths appear to strongly correlate with the number of
water molecules which form hydrogen bonds with the COO- group. Furthermore, the
hydrogen bond lengths are shorter and the hydrogen bond angles are larger for
L-alanine in water as compared to crystal. Overall, our findings strongly
suggest that the generally accepted approach of extending the structural
information acquired from crystallographic data to a L-alanine molecule in
aqueous solution should be used with caution.
| [
{
"version": "v1",
"created": "Fri, 20 Apr 2007 12:39:44 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Degtyarenko",
"Ivan",
""
],
[
"Jalkanen",
"Karl J.",
""
],
[
"Gurtovenko",
"Andrey A.",
""
],
[
"Nieminen",
"Risto M.",
""
]
] |
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