id
stringlengths 9
16
| submitter
stringlengths 1
64
⌀ | authors
stringlengths 3
36.7k
| title
stringlengths 1
382
| comments
stringlengths 1
1.15k
⌀ | journal-ref
stringlengths 1
557
⌀ | doi
stringlengths 7
153
⌀ | report-no
stringlengths 1
479
⌀ | categories
stringlengths 5
125
| license
stringclasses 9
values | abstract
stringlengths 6
6.09k
| versions
list | update_date
timestamp[s] | authors_parsed
sequence |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
0705.0698 | David M. Bradley | Xia Zhou, Tianxin Cai (Zhejiang University), David M. Bradley | Signed q-Analogs of Tornheim's Double Series | 12 pages, AMSLaTeX. The multinomial notation introduced on page 3
just before Theorem 1 is insufficiently general in version 1, since it may
happen that the upper number is negative. This is corrected in version 2,
which allows for a negative or even complex upper argument | Proceedings of the American Mathematical Society, Vol 136, No. 8,
August 2008, pp. 2689--2698 | 10.1090/S0002-9939-08-09208-3 | null | math.NT math.CA | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We introduce signed q-analogs of Tornheim's double series, and evaluate them
in terms of double q-Euler sums. As a consequence, we provide explicit
evaluations of signed and unsigned Tornheim double series, and correct some
mistakes in the literature.
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 20:05:27 GMT"
},
{
"version": "v2",
"created": "Fri, 18 Jul 2008 05:09:09 GMT"
}
] | 2008-07-18T00:00:00 | [
[
"Zhou",
"Xia",
"",
"Zhejiang University"
],
[
"Cai",
"Tianxin",
"",
"Zhejiang University"
],
[
"Bradley",
"David M.",
""
]
] |
0705.0699 | Lynn D. Matthews | L. D. Matthews, C. Goddi, L. J. Greenhill, C. J. Chandler, M. J. Reid,
and E. M. L. Humphreys | A Documentary of High-Mass Star Formation: Probing the Dynamical
Evolution of Orion Source I on 10-100 AU Scales using SiO Masers | 5 pages; to appear in the proceedings of IAU Symposium 242,
Astrophysical Masers and their Environments, ed. J. Chapman & W. Baan | null | 10.1017/S1743921307012689 | null | astro-ph | null | A comprehensive picture of high-mass star formation has remained elusive, in
part because examples of high-mass YSOs tend to be relatively distant, deeply
embedded, and confused with other emission sources. These factors have impeded
dynamical investigations within tens of AU of high-mass YSOs--scales that are
critical for probing the interfaces where outflows from accretion disks are
launched and collimated. Using observations of SiO masers obtained with the VLA
and the VLBA, the KaLYPSO project is overcoming these limitations by mapping
the structure and dynamical/temporal evolution of the material 10-1000 AU from
the nearest high-mass YSO: Radio Source I in the Orion BN/KL region. Our data
include ~40 epochs of VLBA observations over a several-year period, allowing us
to track the proper motions of individual SiO maser spots and to monitor
changes in the physical conditions of the emitting material with time.
Ultimately these data will provide 3-D maps of the outflow structure over
approximately 30% of the outflow crossing time. Here we summarize recent
results from the KaLYPSO project, including evidence that high-mass star
formation is occurring via disk-mediated accretion.
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 20:05:43 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Matthews",
"L. D.",
""
],
[
"Goddi",
"C.",
""
],
[
"Greenhill",
"L. J.",
""
],
[
"Chandler",
"C. J.",
""
],
[
"Reid",
"M. J.",
""
],
[
"Humphreys",
"E. M. L.",
""
]
] |
0705.0700 | Raydonal Ospina | Raydonal Ospina and Silvia L. P. Ferrari | Inflated Beta Distributions | 15 pages, 4 figures. Submitted to Statistical Papers | null | 10.1007/s00362-008-0125-4 | null | stat.ME | null | This paper considers the issue of modeling fractional data observed in the
interval [0,1), (0,1] or [0,1]. Mixed continuous-discrete distributions are
proposed. The beta distribution is used to describe the continuous component of
the model since its density can have quite diferent shapes depending on the
values of the two parameters that index the distribution. Properties of the
proposed distributions are examined. Also, maximum likelihood and method of
moments estimation is discussed. Finally, practical applications that employ
real data are presented.
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 20:20:40 GMT"
},
{
"version": "v2",
"created": "Mon, 8 Oct 2007 19:42:20 GMT"
},
{
"version": "v3",
"created": "Sun, 11 Nov 2007 21:28:29 GMT"
}
] | 2008-03-19T00:00:00 | [
[
"Ospina",
"Raydonal",
""
],
[
"Ferrari",
"Silvia L. P.",
""
]
] |
0705.0701 | Chick Woodward | G.J. Schwarz, C.E. Woodward, M.F. Bode, A. Evans, S.P. Eyres, T.R.
Geballe, R.D. Gehrz, M.A. Greenhouse, P.H. Hauschildt, L.A. Helton, D.K.
Lynch, J.E. Lyke, T.J. O'Brien, R.W. Russell, R.J. Rudy, S.N. Shore, S.G.
Starrfield, T. Temim, J.W. Truran, C.C. Venturini, R.E. Williams, and R.
Zamanov | The Early Spectrophotometric Evolution of V1186 Scorpii (Nova Scorpii
2004 #1) | 7 figures, 37 pages. Astronimocal Journal accepted | Astron.J.134:516-526,2007 | 10.1086/519240 | null | astro-ph | null | We report optical photometry and optical through mid-infrared spectroscopy of
the classical nova V1186 Sco. This slowly developing nova had an complex light
curve with multiple secondary peaks similar to those seen in PW Vul. The time
to decline 2 magnitudes, t$_2$, was 20 days but the erratic nature of the light
curve makes determination of intrinsic properties based on the decline time
(e.g., luminosity) problematic, and the often cited MMRD relationship of Della
Valle and Livio (1995) fails to yield a plausible distance. Spectra covering
0.35 to 35 $\mu$m were obtained in two separate epochs during the first year of
outburst. The first set of spectra, taken about 2 months after visible maximum,
are typical of a CO-type nova with narrow line emission from \ion{H}{1},
\ion{Fe}{2}, \ion{O}{1} and \ion{He}{1}. Later data, obtained between 260 and
380 days after maximum, reveal an emerging nebular spectrum. \textit{Spitzer}
spectra show weakening hydrogen recombination emission with the emergence of
[\ion{Ne}{2}] (12.81 $\mu$m) as the strongest line. Strong emission from
[\ion{Ne}{3}] (15.56 $\mu$m) is also detected. Photoionization models with low
effective temperature sources and only marginal neon enhancement (Ne $\sim$ 1.3
Ne$_{\odot}$) are consistent with these IR fine-structure neon lines indicating
that V1186 Sco did not occur on a ONeMg white dwarf. In contrast, the slow and
erratic light curve evolution, spectral development, and photoionization
analysis of the ejecta imply the outburst occurred on a low mass CO white
dwarf. We note that this is the first time strong [\ion{Ne}{2}] lines have been
detected so early in the outburst of a CO nova and suggests that the presence
of mid-infrared neon lines is not directly indicative of a ONeMg nova event.
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 20:23:05 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"Schwarz",
"G. J.",
""
],
[
"Woodward",
"C. E.",
""
],
[
"Bode",
"M. F.",
""
],
[
"Evans",
"A.",
""
],
[
"Eyres",
"S. P.",
""
],
[
"Geballe",
"T. R.",
""
],
[
"Gehrz",
"R. D.",
""
],
[
"Greenhouse",
"M. A.",
""
],
[
"Hauschildt",
"P. H.",
""
],
[
"Helton",
"L. A.",
""
],
[
"Lynch",
"D. K.",
""
],
[
"Lyke",
"J. E.",
""
],
[
"O'Brien",
"T. J.",
""
],
[
"Russell",
"R. W.",
""
],
[
"Rudy",
"R. J.",
""
],
[
"Shore",
"S. N.",
""
],
[
"Starrfield",
"S. G.",
""
],
[
"Temim",
"T.",
""
],
[
"Truran",
"J. W.",
""
],
[
"Venturini",
"C. C.",
""
],
[
"Williams",
"R. E.",
""
],
[
"Zamanov",
"R.",
""
]
] |
0705.0702 | Masahiro Tsujimoto | M. Tsujimoto, E. D. Feigelson, L. K. Townsley, P. S. Broos, K. V.
Getman, J. Wang, G. P. Garmire, D. Baba, T. Nagayama, M. Tamura, and E. B.
Churchwell | An X-ray Imaging Study of the Stellar Population in RCW49 | 19 pages, 17 figures, 4 tables. ApJ in press | Astrophys.J.665:719-735,2007 | 10.1086/519681 | null | astro-ph | null | We present the results of a high-resolution X-ray imaging study of the
stellar population in the Galactic massive star-forming region RCW49 and its
central OB association Westerlund 2. We obtained a 40 ks X-ray image of a
17'x17' field using the Chandra X-ray Observatory and deep NIR images using the
Infrared Survey Facility in a concentric 8'3x8'3 region. We detected 468 X-ray
sources and identified optical, NIR, and Spitzer Space Telescope MIR
counterparts for 379 of them. The unprecedented spatial resolution and
sensitivity of the X-ray image, enhanced by optical and infrared imaging data,
yielded the following results: (1) The central OB association Westerlund 2 is
resolved for the first time in the X-ray band. X-ray emission is detected from
all spectroscopically-identified early-type stars in this region. (2) Most
(86%) X-ray sources with optical or infrared identifications are cluster
members in comparison with a control field in the Galactic Plane. (3) A loose
constraint (2--5 kpc) for the distance to RCW49 is derived from the mean X-ray
luminosity of T Tauri stars. (4) The cluster X-ray population consists of
low-mass pre--main-sequence and early-type stars as obtained from X-ray and NIR
photometry. About 30 new OB star candidates are identified. (5) We estimate a
cluster radius of 6'--7' based on the X-ray surface number density profiles.
(6) A large fraction (90%) of cluster members are identified individually using
complimentary X-ray and MIR excess emission. (7) The brightest five X-ray
sources, two Wolf-Rayet stars and three O stars, have hard thermal spectra.
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 20:32:15 GMT"
}
] | 2019-08-19T00:00:00 | [
[
"Tsujimoto",
"M.",
""
],
[
"Feigelson",
"E. D.",
""
],
[
"Townsley",
"L. K.",
""
],
[
"Broos",
"P. S.",
""
],
[
"Getman",
"K. V.",
""
],
[
"Wang",
"J.",
""
],
[
"Garmire",
"G. P.",
""
],
[
"Baba",
"D.",
""
],
[
"Nagayama",
"T.",
""
],
[
"Tamura",
"M.",
""
],
[
"Churchwell",
"E. B.",
""
]
] |
0705.0703 | Daniel Boyanovsky | D. Boyanovsky, C.M.Ho | Production of a sterile species: quantum kinetics | To appear in Phys. Rev. D | Phys.Rev.D76:085011,2007 | 10.1103/PhysRevD.76.085011 | null | hep-ph | null | Production of a sterile species is studied within an effective model of
active-sterile neutrino mixing in a medium in thermal equilibrium. The quantum
kinetic equations for the distribution functions and coherences are obtained
from two independent methods: the effective action and the quantum master
equation. The decoherence time scale for active-sterile oscillations is
$\tau_{dec} = 2/\Gamma_{aa}$, but the evolution of the distribution functions
is determined by the two different time scales associated with the damping
rates of the quasiparticle modes in the medium: $\Gamma_1=\Gamma_{aa}\cos^2\tm
; \Gamma_2=\Gamma_{aa}\sin^2\tm$ where $\Gamma_{aa}$ is the interaction rate of
the active species in absence of mixing and $\tm$ the mixing angle in the
medium. These two time scales are widely different away from MSW resonances and
preclude the kinetic description of active-sterile production in terms of a
simple rate equation. We give the complete set of quantum kinetic equations for
the active and sterile populations and coherences and discuss in detail the
various approximations. A generalization of the active-sterile transition
probability \emph{in a medium} is provided via the quantum master equation. We
derive explicitly the usual quantum kinetic equations in terms of the
``polarization vector'' and show their equivalence to those obtained from the
quantum master equation and effective action.
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 20:31:40 GMT"
},
{
"version": "v2",
"created": "Fri, 5 Oct 2007 18:55:02 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Boyanovsky",
"D.",
""
],
[
"Ho",
"C. M.",
""
]
] |
0705.0704 | Kevin Flood | The BABAR Collaboration, B. Aubert, et al | Search for $D^0-{\bar D}^0$ Mixing Using Doubly Flavor Tagged
Semileptonic Decay Modes | 13 pages, 7 figures, submitted to Phys.Rev.D | Phys.Rev.D76:014018,2007 | 10.1103/PhysRevD.76.014018 | SLAC-PUB-12494 | hep-ex | null | We have searched for $D^0 - \bar{D}^0$ mixing in $D^{*+} \to \pi^+ D^0$
decays with $D^0 \to K^{(*)} e \nu$ in a sample of $e^+ e^- \to {c\bar c}$
events produced near 10.58 GeV. The charge of the slow pion from charged $D^*$
decay tags the charm flavor at production, and it is required to be consistent
with the flavor of a fully reconstructed second charm decay in the same event.
We observe 3 mixed candidates compared to 2.85 background events expected from
simulation. We ascribe a 50% systematic uncertainty to this expected background
rate. We find a central value for the mixing rate of $0.4 \times 10^{-4}$.
Using a frequentist method, we set corresponding 68% and 90% confidence
intervals at $(-5.6, 7.4) \times 10^{-4}$ and $(-13, 12) \times 10^{-4}$,
respectively.
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 20:39:15 GMT"
},
{
"version": "v2",
"created": "Wed, 9 May 2007 19:37:37 GMT"
}
] | 2010-04-12T00:00:00 | [
[
"The BABAR Collaboration",
"",
""
],
[
"Aubert",
"B.",
""
]
] |
0705.0705 | Vincent Rivasseau | Vincent Rivasseau | Non-commutative Renormalization | 82 pages, Poincare Seminar, updated and expanded version of
arXiv:hep-th/0702068 | null | 10.1007/978-3-7643-7434-1_19 | null | hep-th | null | A new version of scale analysis and renormalization theory has been found on
the non-commutative Moyal space. It could be useful for physics beyond the
standard model or for standard physics in strong external field. The good news
is that quantum field theory is better behaved on non-commutative than on
ordinary space: indeed it has no Landau ghost. Noncommutativity might therefore
be an alternative to supersymmetry. We review this rapidly growing subject.
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 20:41:02 GMT"
}
] | 2015-05-13T00:00:00 | [
[
"Rivasseau",
"Vincent",
""
]
] |
0705.0706 | Vladimir Sudilovsky Mr. | Vladimir Sudilovsky (1,2), Sandra Savaglio (2), Paul Vreeswijk (3),
Cedric Ledoux (3), Alain Smette (3), Jochen Greiner (2) ((1) Guilford
College, North Carolina, (2) MPE, (3) ESO) | Intervening Metal Systems in GRB and QSO sight-lines: The Mgii and Civ
Question | 21 pages, 4 figures, ApJ accepted, Revised after Referee Report | null | 10.1086/521525 | null | astro-ph | null | Prochter et al. 2006 recently found that the number density of strong
intervening 0.5<z<2 MgII absorbers detected in gamma-ray burst (GRB) afterglow
spectra is nearly 4 times larger than in QSO spectra. We have conducted a
similar study using CIV absorbers. Our CIV sample, consisting of a total of 20
systems, is drawn from 3 high resolution and high to moderate S/N VLT/UVES
spectra of 3 long-duration GRB afterglows, covering the redshift interval 1.6<
z<3.1. The column density distribution and number density of this sample do not
show any statistical difference with the same quantities measured in QSO
spectra. We discuss several possibilities for the discrepancy between CIV and
MgII absorbers and conclude that a higher dust extinction in the MgII QSO
samples studied up to now would give the most straightforward solution.
However, this effect is only important for the strong MgII absorbers.
Regardless of the reasons for this discrepancy, this result confirms once more
that GRBs can be used to detect a side of the universe that was unknown before,
not necessarily connected with GRBs themselves, providing an alternative and
fundamental investigative tool of the cosmic evolution of the universe.
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 20:41:37 GMT"
},
{
"version": "v2",
"created": "Thu, 5 Jul 2007 09:21:22 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Sudilovsky",
"Vladimir",
""
],
[
"Savaglio",
"Sandra",
""
],
[
"Vreeswijk",
"Paul",
""
],
[
"Ledoux",
"Cedric",
""
],
[
"Smette",
"Alain",
""
],
[
"Greiner",
"Jochen",
""
]
] |
0705.0707 | Brenda L. Dingus | A. A. Abdo, B. Allen, D. Berley, S. Casanova, C. Chen, D. G. Coyne, B.
L. Dingus, R. W. Ellsworth, L. Fleysher, R. Fleysher, M. M. Gonzalez, J. A.
Goodman, E. Hays, C. M. Hoffman, B. Hopper, P. H. Huntemeyer, B. E.
Kolterman, C. P. Lansdell, J. T. Linnemann, J. E. McEnery, A. I. Mincer, P.
Nemethy, D. Noyes, J. M. Ryan, P. M. Saz Parkinson, A. Shoup, G. Sinnis, A.
J. Smith, G. W. Sullivan, V. Vasileiou, G. P. Walker, D. A. Williams, X. W.
Xu, and G. B. Yodh | TeV Gamma-Ray Sources from a Survey of the Galactic Plane with Milagro | Submitted to ApJ | Astrophys.J.664:L91-L94,2007 | 10.1086/520717 | null | astro-ph | null | A survey of Galactic gamma-ray sources at a median energy of ~20 TeV has been
performed using the Milagro Gamma Ray Observatory. Eight candidate sources of
TeV emission are detected with pre-trials significance $>4.5\sigma$ in the
region of Galactic longitude $l\in[30^\circ,220^\circ]$ and latitude
$b\in[-10^\circ,10^\circ]$. Four of these sources, including the Crab nebula
and the recently published MGRO J2019+37, are observed with significances
$>4\sigma$ after accounting for the trials involved in searching the 3800
square degree region. All four of these sources are also coincident with EGRET
sources. Two of the lower significance sources are coincident with EGRET
sources and one of these sources is Geminga. The other two candidates are in
the Cygnus region of the Galaxy. Several of the sources appear to be spatially
extended. The fluxes of the sources at 20 TeV range from ~25% of the Crab flux
to nearly as bright as the Crab.
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 20:42:24 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"Abdo",
"A. A.",
""
],
[
"Allen",
"B.",
""
],
[
"Berley",
"D.",
""
],
[
"Casanova",
"S.",
""
],
[
"Chen",
"C.",
""
],
[
"Coyne",
"D. G.",
""
],
[
"Dingus",
"B. L.",
""
],
[
"Ellsworth",
"R. W.",
""
],
[
"Fleysher",
"L.",
""
],
[
"Fleysher",
"R.",
""
],
[
"Gonzalez",
"M. M.",
""
],
[
"Goodman",
"J. A.",
""
],
[
"Hays",
"E.",
""
],
[
"Hoffman",
"C. M.",
""
],
[
"Hopper",
"B.",
""
],
[
"Huntemeyer",
"P. H.",
""
],
[
"Kolterman",
"B. E.",
""
],
[
"Lansdell",
"C. P.",
""
],
[
"Linnemann",
"J. T.",
""
],
[
"McEnery",
"J. E.",
""
],
[
"Mincer",
"A. I.",
""
],
[
"Nemethy",
"P.",
""
],
[
"Noyes",
"D.",
""
],
[
"Ryan",
"J. M.",
""
],
[
"Parkinson",
"P. M. Saz",
""
],
[
"Shoup",
"A.",
""
],
[
"Sinnis",
"G.",
""
],
[
"Smith",
"A. J.",
""
],
[
"Sullivan",
"G. W.",
""
],
[
"Vasileiou",
"V.",
""
],
[
"Walker",
"G. P.",
""
],
[
"Williams",
"D. A.",
""
],
[
"Xu",
"X. W.",
""
],
[
"Yodh",
"G. B.",
""
]
] |
0705.0708 | Martin Legare | M. Legare | On Certain Quantization Aspects of (Generalized) Toda Systems | 17 pages | null | null | null | math-ph math.MP | null | Ordinary and gl(n,R) generalized Toda systems as well as a related hierarchy
are probed with respect to certain quantization characteristics. "Quantum"
canonical and Poisson transformations are used to study quantizations of
transformed Toda systems. With a Lax pair setting, a hierarchy of related
systems are shown and their quantizations discussed. Finally, comments are
added about quantum aspects of gl(n,R) generalized Toda systems with the
approaches of deformation quantization or quantum groups in mind.
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 20:52:34 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Legare",
"M.",
""
]
] |
0705.0709 | Imran Ahmed | Imran Ahmed | Polar Cremona Transformations and Monodromy of Polynomials | 8 pages | Studia Scientiarum Mathematicarum Hungarica 47(1), 81-89 (2010) | 10.1556/SScMath.2009.1114 | null | math.AG | null | Consider the gradient map associated to any non-constant homogeneous
polynomial $f\in \C[x_0,...,x_n]$ of degree $d$, defined by \[\phi_f=grad(f):
D(f)\to \CP^n, (x_0:...:x_n)\to (f_0(x):...:f_n(x))\] where $D(f)=\{x\in \CP^n;
f(x)\neq 0\}$ is the principal open set associated to $f$ and
$f_i=\frac{\partial f}{\partial x_i}$. This map corresponds to polar Cremona
transformations. In Proposition \ref{p1} we give a new lower bound for the
degree $d(f)$ of $\phi_f$ under the assumption that the projective hypersurface
$V:f=0 $ has only isolated singularities. When $d(f)=1$, Theorem \ref{t4}
yields very strong conditions on the singularities of $V$.
| [
{
"version": "v1",
"created": "Sat, 5 May 2007 12:00:59 GMT"
}
] | 2010-03-10T00:00:00 | [
[
"Ahmed",
"Imran",
""
]
] |
0705.0710 | Claude LeBrun | Xiuxiong Chen, Claude LeBrun, and Brian Weber | On Conformally Kaehler, Einstein Manifolds | 45 pages, 9 figures. Simplified proof of Lemma 25. Several minor
corrections to section 5 | null | null | null | math.DG gr-qc math.AG math.AP | null | We prove that any compact complex surface with positive first Chern class
admits an Einstein metric which is conformally related to a Kaehler metric. The
key new ingredient is the existence of such a metric on the blow-up of the
complex projective plane at two distinct points.
| [
{
"version": "v1",
"created": "Mon, 7 May 2007 14:29:01 GMT"
},
{
"version": "v2",
"created": "Wed, 30 May 2007 19:47:07 GMT"
}
] | 2007-06-13T00:00:00 | [
[
"Chen",
"Xiuxiong",
""
],
[
"LeBrun",
"Claude",
""
],
[
"Weber",
"Brian",
""
]
] |
0705.0711 | Jane Arthur | S. J. Arthur | Off-center HII regions in power-law density distributions | 9 pages, 10 figures, emulate ApJ style, submitted to The
Astrophysical Journal | null | 10.1086/521428 | null | astro-ph | null | The expansion of ionization fronts in uniform and spherically symmetric
power-law density distributions is a well-studied topic. However, in many
situations, such as a star formed at the edge of a molecular cloud core, an
offset power-law density distribution would be more appropriate. In this paper
a few of the main issues of the formation and expansion of HII regions in such
media are outlined and results are presented for the particular cases where the
underlying power laws are 1/r^2 and 1/r^3. A simple criterion is developed for
determining whether the initial photoionized region will be unbounded, which
depends on the power-law exponent and the ratio of the equivalent Stroemgren
radius produced by the star in a uniform medium to the stellar offset distance.
In the expansion stage, the ionized volumes will eventually become unbounded
unless pressure balance with the external medium is reached before the
ionization front velocity becomes supersonic with respect to the ionized gas.
| [
{
"version": "v1",
"created": "Sat, 5 May 2007 02:45:55 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Arthur",
"S. J.",
""
]
] |
0705.0712 | William Gordon Ritter | Arthur Jaffe (1) and Gordon Ritter (1) ((1) Harvard University) | Reflection Positivity and Monotonicity | 11 pages | J.Math.Phys.49:052301,2008 | 10.1063/1.2907660 | null | math-ph math.AP math.DG math.FA math.MP | null | We prove general reflection positivity results for both scalar fields and
Dirac fields on a Riemannian manifold, and comment on applications to quantum
field theory. As another application, we prove the inequality $C_D \leq C_N$
between Dirichlet and Neumann covariance operators on a manifold with a
reflection.
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 21:37:36 GMT"
},
{
"version": "v2",
"created": "Wed, 9 May 2007 04:23:08 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Jaffe",
"Arthur",
"",
"Harvard University"
],
[
"Ritter",
"Gordon",
"",
"Harvard University"
]
] |
0705.0713 | Jack Harris | J. G. E. Harris, S. V. Nguyen, S. C. Doret, W. Ketterle, and J. M.
Doyle | Spin-exchange collisions of submerged shell atoms below 1 Kelvin | 16 pages, 2 figs | null | 10.1103/PhysRevLett.99.223201 | null | physics.atom-ph | null | Angular momentum changing collisions can be suppressed in atoms whose valence
electrons are submerged beneath filled shells of higher principle quantum
number. To determine whether spin-exchange collisions are suppressed in these
"submerged shell" atoms, we measured spin-exchange collisions of six hyperfine
states of Mn at temperatures below 1 K. Although the 3d valence electrons in Mn
are submerged beneath a filled 4s orbital, we find that the spin exchange rate
coefficients are similar to those of Na and H (which are non-submerged shell
atoms).
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 21:49:38 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Harris",
"J. G. E.",
""
],
[
"Nguyen",
"S. V.",
""
],
[
"Doret",
"S. C.",
""
],
[
"Ketterle",
"W.",
""
],
[
"Doyle",
"J. M.",
""
]
] |
0705.0714 | Mu-Chun Chen | Mu-Chun Chen and K.T. Mahanthappa | CKM and Tri-bimaximal MNS Matrices in a SU(5) x (d)T Model | 11 pages; v2: additional references added; minor modifications made;
conclusion unchanged; v3: version to appear in Phys. Lett. B | Phys.Lett.B652:34-39,2007 | 10.1016/j.physletb.2007.06.064 | COLO-HEP-527, UCI-TR-2007-21, FERMILAB-PUB-07-108-T | hep-ph | null | We propose a model based on SU(5) x {}^{(d)}T which successfully gives rise
to near tri-bimaximal leptonic mixing as well as realistic CKM matrix elements
for the quarks. The Georgi-Jarlskog relations for three generations are also
obtained. Due to the {}^{(d)}T transformation property of the matter fields,
the b-quark mass can be generated only when the {}^{(d)}T symmetry is broken,
giving a dynamical origin for the hierarchy between m_{b} and m_{t}. There are
only nine operators allowed in the Yukawa sector up to at least mass dimension
seven due to an additional Z_{12} x Z'_{12} symmetry, which also forbids, up to
some high orders, operators that lead to proton decay. The resulting model has
a total of nine parameters in the charged fermion and neutrino sectors, and
hence is very predictive. In addition to the prediction for \theta_{13} \simeq
\theta_{c}/3 \sqrt{2}, the model gives rise to a sum rule,
\tan^{2}\theta_{\odot} \simeq \tan^{2} \theta_{\odot, \mathrm{TBM}} - {1/2}
\theta_{c} \cos\beta, which is a consequence of the Georgi-Jarlskog relations
in the quark sector. This deviation could account for the difference between
the experimental best fit value for the solar mixing angle and the value
predicted by the tri-bimaximal mixing matrix.
| [
{
"version": "v1",
"created": "Mon, 7 May 2007 17:24:19 GMT"
},
{
"version": "v2",
"created": "Tue, 15 May 2007 20:22:23 GMT"
},
{
"version": "v3",
"created": "Thu, 28 Jun 2007 19:13:14 GMT"
}
] | 2010-04-06T00:00:00 | [
[
"Chen",
"Mu-Chun",
""
],
[
"Mahanthappa",
"K. T.",
""
]
] |
0705.0715 | Van Vu H. | Van Vu | Sum-product estimates via directed expanders | null | null | null | null | math.CO math.NT | null | Let $\F_q$ be a finite field of order $q$ and $P$ be a polynomial in
$\F_q[x_1, x_2]$. For a set $A \subset \F_q$, define $P(A):=\{P(x_1, x_2) | x_i
\in A \}$. Using certain constructions of expanders, we characterize all
polynomials $P$ for which the following holds
\vskip2mm \centerline{\it If $|A+A|$ is small, then $|P(A)|$ is large.}
\vskip2mm
The case $P=x_1x_2$ corresponds to the well-known sum-product problem.
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 22:49:01 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Vu",
"Van",
""
]
] |
0705.0716 | Chris L. Fryer | Chris L. Fryer (LANL/UA), Aimee L. Hungerford (LANL) and Patrick A.
Young (LANL/UA) | Light Curve Calculations of Supernovae from Fallback Gamma-Ray Bursts | 11 pages (including 3 figures), submitted to ApJ, comments welcome | null | 10.1086/519523 | LA-UR-07-1376 | astro-ph | null | The currently-favored model for long-duration gamma-ray bursts (GRBs) invokes
explosions from the collapse of a massive star down to a black hole: either
directly or through fallback. Those GRBs forming via fallback will produce much
less radioactive nickel, and hence it has been argued (without any real
calculation) that these systems produce dim supernovae. These fallback
black-hole GRBs have been recently been argued as possible progenitors of a
newly discovered set of GRBs lacking any associated supernovae. Here we present
the first ever radiation-hydrodynamics calculations of the light-curves
produced in the hypernova explosion by a delayed-fallback gamma-ray burst. We
find that the bolometric light-curve is dominated by shock-deposited energy,
not the decay of radioactive elements. As such, observations of such bursts
actually probe the density in the progenitor wind more than it does the
production of radioactive nickel.
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 22:55:27 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Fryer",
"Chris L.",
"",
"LANL/UA"
],
[
"Hungerford",
"Aimee L.",
"",
"LANL"
],
[
"Young",
"Patrick A.",
"",
"LANL/UA"
]
] |
0705.0717 | Prakash Belkale | Prakash Belkale | Strange duality and the Hitchin/WZW connection | The only change made is a clarification of the recent history of the
strange duality conjecture | null | null | null | math.AG math.RT | null | For a compact Riemann surface X of positive genus, the space of sections of
certain theta bundle on moduli of bundles of rank r and level k admits a
natural map to (the dual of) a similar space of sections of rank k and level r
(the strange duality isomorphism). Both sides of the isomorphism carry
projective connections as X varies in a family. We prove that this map is
(projectively) flat.
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 23:20:42 GMT"
},
{
"version": "v2",
"created": "Tue, 8 May 2007 23:16:31 GMT"
},
{
"version": "v3",
"created": "Thu, 24 May 2007 18:14:13 GMT"
},
{
"version": "v4",
"created": "Thu, 18 Oct 2007 18:49:46 GMT"
},
{
"version": "v5",
"created": "Fri, 15 Feb 2008 22:15:29 GMT"
}
] | 2008-02-16T00:00:00 | [
[
"Belkale",
"Prakash",
""
]
] |
0705.0718 | Yuri Popov | Yuri O. Popov, Jonghoon Lee, Glenn H. Fredrickson (University of
California, Santa Barbara) | Field-Theoretic Simulations of Polyelectrolyte Complexation | 7 pages, 3 figures, 3 equations, LaTeX; accepted to Journal of
Polymer Science B: Polymer Physics; v2: a revised and expanded version, 6
paragraphs of text and about 20 references added | Journal of Polymer Science B: Polymer Physics, 45, 3223-3230
(2007) | 10.1002/polb.21334 | null | cond-mat.soft cond-mat.mtrl-sci | null | We briefly discuss our recent field-theoretic study of polyelectrolyte
complexation, which occurs in solutions of two oppositely charged
polyelectrolytes. Charged systems require theoretical methods beyond the
mean-field (or self-consistent field) approximation; indeed, mean-field theory
is qualitatively incorrect for such polyelectrolyte solutions. Both analytical
(one-loop) and numerical (complex Langevin) methods to account for charge
correlations are discussed. In particular, the first application of
field-theoretic simulations to polyelectrolyte systems is reported. The
polyelectrolyte charge-charge correlation length and a phase diagram are
provided; effects of charge redistribution are qualitatively explored.
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 23:27:22 GMT"
},
{
"version": "v2",
"created": "Mon, 16 Jul 2007 06:41:10 GMT"
}
] | 2015-05-13T00:00:00 | [
[
"Popov",
"Yuri O.",
"",
"University of\n California, Santa Barbara"
],
[
"Lee",
"Jonghoon",
"",
"University of\n California, Santa Barbara"
],
[
"Fredrickson",
"Glenn H.",
"",
"University of\n California, Santa Barbara"
]
] |
0705.0719 | Edward Flach | E. H. Flach and S. Schnell and J. Norbury | Limit cycles in the presence of convection, a travelling wave analysis | 20 pages, 5 figures | null | 10.1103/PhysRevE.76.036216 | null | math.AP | null | We consider a diffusion model with limit cycle reaction functions, in the
presence of convection. We select a set of functions derived from a realistic
reaction model: the Schnakenberg equations. This resultant form is
unsymmetrical. We find a transformation which maps the irregular equations into
model form. Next we transform the dependent variables into polar form. From
here, a travelling wave analysis is performed on the radial variable. Results
are complex, but we make some simple estimates.
We carry out numerical experiments to test our analysis. An initial `knock'
starts the propagation of pattern. The speed of the travelling wave is not
quite as expected. We investigate further. The system demonstrates distinctly
different behaviour to the left and the right. We explain how this phenomenon
occurs by examining the underlying behaviour.
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 23:47:27 GMT"
},
{
"version": "v2",
"created": "Mon, 4 Jun 2007 04:43:05 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Flach",
"E. H.",
""
],
[
"Schnell",
"S.",
""
],
[
"Norbury",
"J.",
""
]
] |
0705.0720 | Paul Halpern | Paul Halpern | Energy Distribution of a Charged Black Hole with a Minimally Coupled
Scalar Field | 11 pages; To appear in Astrophysics and Space Science | Astrophys.SpaceSci.313:357-361,2008 | 10.1007/s10509-007-9704-4 | null | gr-qc astro-ph | null | Using three different energy-momentum complexes, the Einstein,
Landau-Lifshitz, and Papapetrou prescriptions, we calculate the energy of an
electrically charged black hole exact solution with a self-interacting,
minimally-coupled scalar field and the asymptotic region locally an
Anti-deSitter spacetime. Writing the metric in Kerr-Schild Cartesian
coordinates, we demonstrate that this metric belongs to the Kerr-Schild class
of solutions. Applying each of the three energy-momentum prescriptions and
comparing the results, we find consistency among these complexes, suggesting
their utility as localized measures of energy.
| [
{
"version": "v1",
"created": "Sat, 5 May 2007 01:25:14 GMT"
},
{
"version": "v2",
"created": "Wed, 30 May 2007 15:28:27 GMT"
},
{
"version": "v3",
"created": "Thu, 1 Nov 2007 02:08:17 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Halpern",
"Paul",
""
]
] |
0705.0721 | Julien Toulouse | Julien Toulouse, Roland Assaraf and C. J. Umrigar | Zero-variance zero-bias quantum Monte Carlo estimators of the
spherically and system-averaged pair density | 13 pages, 9 figures, published version | Journal of Chemical Physics 126, 244112 (2007) | 10.1063/1.2746029 | null | physics.chem-ph cond-mat.mtrl-sci cond-mat.other physics.comp-ph | null | We construct improved quantum Monte Carlo estimators for the spherically- and
system-averaged electron pair density (i.e. the probability density of finding
two electrons separated by a relative distance u), also known as the
spherically-averaged electron position intracule density I(u), using the
general zero-variance zero-bias principle for observables, introduced by
Assaraf and Caffarel. The calculation of I(u) is made vastly more efficient by
replacing the average of the local delta-function operator by the average of a
smooth non-local operator that has several orders of magnitude smaller
variance. These new estimators also reduce the systematic error (or bias) of
the intracule density due to the approximate trial wave function. Used in
combination with the optimization of an increasing number of parameters in
trial Jastrow-Slater wave functions, they allow one to obtain well converged
correlated intracule densities for atoms and molecules. These ideas can be
applied to calculating any pair-correlation function in classical or quantum
Monte Carlo calculations.
| [
{
"version": "v1",
"created": "Sat, 5 May 2007 01:41:22 GMT"
},
{
"version": "v2",
"created": "Fri, 29 Jun 2007 20:10:43 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Toulouse",
"Julien",
""
],
[
"Assaraf",
"Roland",
""
],
[
"Umrigar",
"C. J.",
""
]
] |
0705.0722 | Takuya Okuda | Takuya Okuda | BIons in topological string theory | 21 pages; v.2 references added; v.3 reference added; v.4 minor
corrections; v.5 substantial rewriting | JHEP 0801:062,2008 | 10.1088/1126-6708/2008/01/062 | NSF-KITP-07-109 | hep-th | null | When many fundamental strings are stacked together, they puff up into
D-branes. BIons and giant gravitons are the examples of such D-brane
configurations that arise from coincident strings. We propose and demonstrate
analogous transitions in topological string theory. Such transitions can also
be understood in terms of the Fourier transform of D-brane amplitudes.
| [
{
"version": "v1",
"created": "Sat, 5 May 2007 02:45:46 GMT"
},
{
"version": "v2",
"created": "Mon, 7 May 2007 21:04:19 GMT"
},
{
"version": "v3",
"created": "Fri, 15 Jun 2007 20:22:42 GMT"
},
{
"version": "v4",
"created": "Wed, 12 Sep 2007 20:47:08 GMT"
},
{
"version": "v5",
"created": "Mon, 11 Feb 2008 06:46:20 GMT"
}
] | 2009-04-17T00:00:00 | [
[
"Okuda",
"Takuya",
""
]
] |
0705.0723 | Kannan Soundararajan | K. Soundararajan | Partial sums of the M{\"o}bius function | 11 pages; AIM preprint number 2007-23; Version 2 makes some
expository changes | null | null | null | math.NT math.CA | null | Assuming the Riemann Hypothesis we establish an upper bound for the sum of
the M{\" o}bius function up to $x$. Our method is based on estimating the
frequency with which intervals of a given length can contain an unusual number
of ordinates of zeros of the Riemann zeta-function.
| [
{
"version": "v1",
"created": "Sat, 5 May 2007 03:36:37 GMT"
},
{
"version": "v2",
"created": "Wed, 13 Feb 2008 18:39:48 GMT"
}
] | 2008-02-13T00:00:00 | [
[
"Soundararajan",
"K.",
""
]
] |
0705.0724 | Mushfiq Ahmad Mr. | Mushfiq Ahmad, Muhammad O. G. Talukder | Reciprocal Symmetric Boltzmann Function and Unified Boson-Fermion
Statistics | 6 pages, no figure | null | null | null | physics.gen-ph | null | The differential equation for Boltzmann's function is replaced by the
corresponding discrete finite difference equation. The difference equation is,
then, symmetrized so that the equation remains invariant when step d is
replaced by -d. The solutions of this equation come in Boson-Fermion pairs.
Reciprocal symmetric Boltzmann's function, thus, unifies both Bosonic and
Fermionic distributions.
| [
{
"version": "v1",
"created": "Sat, 5 May 2007 04:18:21 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Ahmad",
"Mushfiq",
""
],
[
"Talukder",
"Muhammad O. G.",
""
]
] |
0705.0725 | Mark Stockman | Maxim Durach, Anastasia Rusina, Keith Nelson, and Mark I. Stockman | Toward Full Spatio-Temporal Control on the Nanoscale | 4 pages, 3 figures Figures were replaced | null | 10.1021/nl071718g | null | physics.optics physics.chem-ph | null | We introduce an approach to implement full coherent control on nanometer
length scales. It is based on spatio-temporal modulation of the surface plasmon
polariton (SPP) fields at the thick edge of a nanowedge. The SPP wavepackets
propagating toward the sharp edge of this nanowedge are compressed and
adiabatically concentrated at a nanofocus, forming an ultrashort pulse of local
fields. The one-dimensional spatial profile and temporal waveform of this pulse
are completely coherently controlled.
| [
{
"version": "v1",
"created": "Sat, 5 May 2007 05:31:26 GMT"
}
] | 2015-05-13T00:00:00 | [
[
"Durach",
"Maxim",
""
],
[
"Rusina",
"Anastasia",
""
],
[
"Nelson",
"Keith",
""
],
[
"Stockman",
"Mark I.",
""
]
] |
0705.0726 | Mark Strovink | Mark Strovink | Diversity of Decline-Rate-Corrected Type Ia Supernova Rise Times: One
Mode or Two? | As accepted by The Astrophysical Journal; 15 pages, 6 figures, 2
tables. Explanatory material rearranged and enhanced; Fig. 4 reformatted | null | 10.1086/523089 | null | astro-ph | null | B-band light-curve rise times for eight unusually well-observed nearby Type
Ia supernovae (SNe) are fitted by a newly developed template-building
algorithm, using light-curve functions that are smooth, flexible, and free of
potential bias from externally derived templates and other prior assumptions.
From the available literature, photometric BVRI data collected over many
months, including the earliest points, are reconciled, combined, and fitted to
a unique time of explosion for each SN. On average, after they are corrected
for light-curve decline rate, three SNe rise in 18.81 +- 0.36 days, while five
SNe rise in 16.64 +- 0.21 days. If all eight SNe are sampled from a single
parent population (a hypothesis not favored by statistical tests), the rms
intrinsic scatter of the decline-rate-corrected SN rise time is 0.96 +0.52
-0.25 days -- a first measurement of this dispersion. The corresponding global
mean rise time is 17.44 +- 0.39 days, where the uncertainty is dominated by
intrinsic variance. This value is ~2 days shorter than two published averages
that nominally are twice as precise, though also based on small samples. When
comparing high-z to low-z SN luminosities for determining cosmological
parameters, bias can be introduced by use of a light-curve template with an
unrealistic rise time. If the period over which light curves are sampled
depends on z in a manner typical of current search and measurement strategies,
a two-day discrepancy in template rise time can bias the luminosity comparison
by ~0.03 magnitudes.
| [
{
"version": "v1",
"created": "Sat, 5 May 2007 05:05:22 GMT"
},
{
"version": "v2",
"created": "Thu, 6 Sep 2007 22:42:19 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Strovink",
"Mark",
""
]
] |
0705.0727 | Armen Nersessian | Armen Nersessian and Vadim Ohanyan | Multi-center MICZ-Kepler systems | 7 pages, typos corrected, refs added. Contribution to the Proceedings
of International Workshop on Classical and Quantum Integrable systems,
24-28.01.2007, Dubna, Russia | Theor.Math.Phys.155:618-626,2008 | 10.1007/s11232-008-0051-6 | null | math-ph hep-th math.MP | null | We present the classical solutions of the two-center MICZ-Kepler and
MICZ-Kepler-Stark systems. Then we suggest the model of multi-center
MICZ-Kepler system on the curved spaces equipped with $so(3)$-invariant
conformal flat metrics.
| [
{
"version": "v1",
"created": "Sat, 5 May 2007 06:06:40 GMT"
},
{
"version": "v2",
"created": "Wed, 18 Jul 2007 09:00:57 GMT"
},
{
"version": "v3",
"created": "Fri, 7 Sep 2007 07:16:35 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Nersessian",
"Armen",
""
],
[
"Ohanyan",
"Vadim",
""
]
] |
0705.0728 | Sergiu Vacaru I. | Sergiu I. Vacaru | Nonholonomic Ricci Flows: Exact Solutions and Gravity | latex2e, 11pt, 39 pages; title changed; typos corrected and updated
references; for publication in EJTP | Electronic Journal of Theoretical Physics (EJTP) 6 (2009) 27-58 | null | null | math-ph gr-qc hep-th math.DG math.MP | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | In a number of physically important cases, the nonholonomically
(nonintegrable) constrained Ricci flows can be modelled by exact solutions of
Einstein equations with nonhomogeneous (anisotropic) cosmological constants. We
develop two geometric methods for constructing such solutions: The first
approach applies the formalism of nonholonomic frame deformations when the
gravitational evolution and field equations transform into systems of nonlinear
partial differential equations which can be integrated in general form. The
second approach develops a general scheme when one (two) parameter families of
exact solutions are defined by any source-free solutions of Einstein's
equations with one (two) Killing vector field(s). A successive iteration
procedure results in a class of solutions characterized by an infinite number
of parameters for a non-Abelian group involving arbitrary functions on one
variable. We also consider nonlinear superpositions of some mentioned classes
of solutions in order to construct more general integral varieties of the Ricci
flow and Einstein equations depending on infinite number of parameters and
three/ four coordinates on four/ five dimensional (semi) Riemannian spaces.
| [
{
"version": "v1",
"created": "Sat, 5 May 2007 19:50:49 GMT"
},
{
"version": "v2",
"created": "Tue, 17 Feb 2009 20:30:00 GMT"
}
] | 2009-02-17T00:00:00 | [
[
"Vacaru",
"Sergiu I.",
""
]
] |
0705.0729 | Sergiu Vacaru I. | Sergiu I. Vacaru | Nonholonomic Ricci Flows and Parametric Deformations of the Solitonic
pp--Waves and Schwarzschild Solutions | latex2e, 11pt, the variant accepted for EJTP | Electronic Journal of Theoretical Physics (EJTP) 6, N21, (2009)
63-93 | null | null | math-ph gr-qc hep-th math.DG math.MP | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We study Ricci flows of some classes of physically valuable solutions in
Einstein and string gravity. The anholonomic frame method is applied for
generic off-diagonal metric ansatz when the field/ evolution equations are
transformed into exactly integrable systems of partial differential equations.
The integral varieties of such solutions, in four and five dimensional gravity,
depend on arbitrary generation and integration functions of one, two and/ or
three variables. Certain classes of nonholonomic frame constraints allow us to
select vacuum and/or Einstein metrics, to generalize such solutions for
nontrivial string (for instance, with antisymmetric torsion fields) and matter
field sources. A very important property of this approach (originating from
Finsler and Lagrange geometry but re-defined for semi-Riemannian spaces) is
that new classes of exact solutions can be generated by nonholonomic
deformations depending on parameters associated to some generalized Geroch
transforms and Ricci flow evolution. In this paper, we apply the method to
construct in explicit form some classes of exact solutions for multi-parameter
Einstein spaces and their nonholonomic Ricci flows describing evolutions/
interactions of solitonic pp-waves and deformations of the Schwarzschild
metric. We explore possible physical consequences and speculate on their
importance in modern gravity.
| [
{
"version": "v1",
"created": "Sat, 5 May 2007 06:18:30 GMT"
},
{
"version": "v2",
"created": "Wed, 9 May 2007 16:37:53 GMT"
},
{
"version": "v3",
"created": "Sat, 2 May 2009 10:06:54 GMT"
}
] | 2009-05-05T00:00:00 | [
[
"Vacaru",
"Sergiu I.",
""
]
] |
0705.0730 | Mushfiq Ahmad Mr. | Mushfiq Ahmad, Muhammad O. G. Talukder | Reciprocal Symmetry and Unified Classico-Quantum Oscillator And
Consistency between a Particle in a Potential Well and a Harmonic Oscillator | 6 pages, no figure | null | null | null | quant-ph | null | The function exp(iwt) describes an oscillating motion. Energy of the
oscillator is proportional to the square of w. exp(iwt) is the solution of a
differential equation. We have replaced this differential equation by the
corresponding finite-time difference equation with d as the smallest span of
time. We have, then, symmetrized the equation so that it remains invariant
under the change d going to -d. This symmetric equation has solutions in pairs.
The angular speed w is modified to w' or w". w' contains a part with an
integer. w" contains a part with a half-integer. This corresponds to quantum
mechanical oscillator energy levels. F= a.exp(iwt) describes oscillation
between -a and +a. If we make w=0, F describes free oscillation between -a and
+a. Reciprocal symmetric oscillator, thus, unifies quantum and classical
harmonic oscillators on one hand, and a harmonic oscillator and a free particle
in a potential well on the other hand. No quantum mechanical postulates are
involved.
| [
{
"version": "v1",
"created": "Sat, 5 May 2007 06:24:22 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Ahmad",
"Mushfiq",
""
],
[
"Talukder",
"Muhammad O. G.",
""
]
] |
0705.0731 | Oleksiy Roslyak V | Oleksiy Roslyak and Joseph L. Birman | Theory of enhanced dynamical photo-thermal bi-stability effects in
cuprous oxide/organic hybrid heterostructure | 6 pages, 7 Figures | null | 10.1016/j.ssc.2007.06.024 | null | cond-mat.mtrl-sci | null | We theoretically demonstrate the formation of multiple bi-stability regions
in the temperature pattern on the interface between a cuprous oxide quantum
well and DCM2:CA:PS organic compound. The Frenkel molecular exciton of the DCM2
is brought into resonance with the $1S$ quadrupole Wannier-Mott exciton in the
cuprous oxide by "solvatochromism" with CA. The resulting hybrid is thermalized
with surrounding helium bath. This leads to strongly non-linear temperature
dependence of the laser field detuning from the quadrupole exciton energy band
which is associated with the temperature induced red shift of the Wannier
exciton energy. Numerical up and down-scan for the detuning reveals
hysteresis-like temperature distribution. The obtained \emph{multiple}
bi-stability regions are at least three orders of magnitude bigger ($meV$) than
the experimentally observed bi-stability in bulk cuprous oxide ($\mu eV$). The
effective absorption curve exhibits highly asymmetrical behavior for the
Frenkel-like (above the $1S$ energy) and Wannier-like (below the $1S$ energy)
branches of the hybrid.
| [
{
"version": "v1",
"created": "Sat, 5 May 2007 06:54:28 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Roslyak",
"Oleksiy",
""
],
[
"Birman",
"Joseph L.",
""
]
] |
0705.0732 | Sergey Zlobin Alekseevich | Jonathan Sondow (New York), Sergey Zlobin (Moscow) | Integrals Over Polytopes, Multiple Zeta Values and Polylogarithms, and
Euler's Constant | 19 pages, to appear in Mat Zametki. Ver 2.: Added Remark 3 on a Chen
(Drinfeld-Kontsevich) iterated integral; simplified Proposition 2; gave
reference for (19); corrected [16]; fixed typo | Math. Notes (in English) 84 (2008) pp. 568-583; Mat. Zametki (in
Russian) 84:4 (2008) pp. 609-626 | 10.1134/S0001434608090290 | null | math.NT math.CV | null | Let $T$ be the triangle with vertices (1,0), (0,1), (1,1). We study certain
integrals over $T$, one of which was computed by Euler. We give expressions for
them both as a linear combination of multiple zeta values, and as a polynomial
in single zeta values. We obtain asymptotic expansions of the integrals, and of
sums of certain multiple zeta values with constant weight. We also give related
expressions for Euler's constant. In the final section, we evaluate more
general integrals -- one is a Chen (Drinfeld-Kontsevich) iterated integral --
over some polytopes that are higher-dimensional analogs of $T$. This leads to a
relation between certain multiple polylogarithm values and multiple zeta
values.
| [
{
"version": "v1",
"created": "Sat, 5 May 2007 07:22:23 GMT"
},
{
"version": "v2",
"created": "Mon, 24 Sep 2007 07:18:08 GMT"
}
] | 2008-10-30T00:00:00 | [
[
"Sondow",
"Jonathan",
"",
"New York"
],
[
"Zlobin",
"Sergey",
"",
"Moscow"
]
] |
0705.0733 | Avijit Lahiri | Avijit Lahiri | Mixing and decoherence to nearest separable states in quantum
measurements | 6 pages, 2 figures | null | null | null | quant-ph | null | We illustrate through numerical results a number of features of
environment-induced decoherence under a broad class of apparatus-environment
interactions in quantum measurements wherein the reduced system-apparatus
density matrix evolves towards the nearest separable state and, in addition,
there occurs a mixing in relevant groups of apparatus microstates (see below).
The resulting final state is unique and correctly embodies the measurement
statistics even in the absence of environment-induced superselection because of
energy differences between these groups of states. The partial transpose
remains non-positive throughout the process.
| [
{
"version": "v1",
"created": "Sat, 5 May 2007 08:32:07 GMT"
},
{
"version": "v2",
"created": "Sat, 26 May 2007 19:01:22 GMT"
}
] | 2007-06-13T00:00:00 | [
[
"Lahiri",
"Avijit",
""
]
] |
0705.0734 | Sanjiang Li | Sanjiang Li and Mingsheng Ying | Soft constraint abstraction based on semiring homomorphism | 18 pages, 1 figure | Theoretical Computer Science 403(2-3) 192-201, 2008 | 10.1016/j.tcs.2008.03.029 | null | cs.AI | null | The semiring-based constraint satisfaction problems (semiring CSPs), proposed
by Bistarelli, Montanari and Rossi \cite{BMR97}, is a very general framework of
soft constraints. In this paper we propose an abstraction scheme for soft
constraints that uses semiring homomorphism. To find optimal solutions of the
concrete problem, the idea is, first working in the abstract problem and
finding its optimal solutions, then using them to solve the concrete problem.
In particular, we show that a mapping preserves optimal solutions if and only
if it is an order-reflecting semiring homomorphism. Moreover, for a semiring
homomorphism $\alpha$ and a problem $P$ over $S$, if $t$ is optimal in
$\alpha(P)$, then there is an optimal solution $\bar{t}$ of $P$ such that
$\bar{t}$ has the same value as $t$ in $\alpha(P)$.
| [
{
"version": "v1",
"created": "Sat, 5 May 2007 08:47:31 GMT"
}
] | 2010-07-01T00:00:00 | [
[
"Li",
"Sanjiang",
""
],
[
"Ying",
"Mingsheng",
""
]
] |
0705.0735 | Ashoke Sen | Justin R. David, Bindusar Sahoo, Ashoke Sen | AdS_3, Black Holes and Higher Derivative Corrections | LaTeX file, 12 pages; v2: reference added | JHEP 0707:058,2007 | 10.1088/1126-6708/2007/07/058 | null | hep-th | null | Using AdS/CFT correspondence and the Euclidean action formalism for black
hole entropy Kraus and Larsen have argued that the entropy of a BTZ black hole
in three dimensional supergravity with (0,4) supersymmetry does not receive any
correction from higher derivative terms in the action. We argue that as a
consequence of AdS/CFT correspondence the action of a three dimensional
supergravity with (0,4) supersymmetry cannot receive any higher derivative
correction except for those which can be removed by field redefinition. The
non-renormalization of the entropy then follows as a consequence of this and
the invariance of Wald's formula under a field redefinition.
| [
{
"version": "v1",
"created": "Sat, 5 May 2007 09:44:53 GMT"
},
{
"version": "v2",
"created": "Sat, 19 May 2007 04:42:49 GMT"
}
] | 2009-04-17T00:00:00 | [
[
"David",
"Justin R.",
""
],
[
"Sahoo",
"Bindusar",
""
],
[
"Sen",
"Ashoke",
""
]
] |
0705.0736 | Tien Quang Nguyen | Nguyen Tien Quang and Pham Le Hong Anh | On monoidal equivalences and Ann-equivalences | 14 pages | null | null | null | math.CT | null | In this paper, we show another proof of the problem by constructing a strict
monoidal category M(C) consisting of M-functors and M-morphisms of a category C
and we prove C is equivalent to it. The proof is based on a basic character of
monoidal equivalences. Ideas and techniques of these proofs can been used to
prove the equivalence between an Ann-category and an almost strict
Ann-category.
| [
{
"version": "v1",
"created": "Sat, 5 May 2007 09:47:01 GMT"
},
{
"version": "v2",
"created": "Wed, 25 May 2011 08:03:13 GMT"
}
] | 2011-05-26T00:00:00 | [
[
"Quang",
"Nguyen Tien",
""
],
[
"Anh",
"Pham Le Hong",
""
]
] |
0705.0737 | Frederic Campana | Frederic Campana | Orbifoldes speciales et classification bimeromorphe des varietes
kaehleriennes compactes | null | null | null | null | math.AG math.CV | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | This is a sequel to [Ca01]=math.AG/0110051. We define the bimeromorphic {\it
category} of geometric orbifolds. These interpolate between (compact K\" ahler)
manifolds and such manifolds with logarithmic structure. These geometric
orbifolds are considered from the point of view of their geometry, and thus
equipped with the usual invariants of varieties: morphisms and bimeromorphic
maps, differential forms, fundamental groups and universal covers, fields of
definition and rational points. The most elementary properties, directly
adapted from the case of varieties without orbifold structure, are established
here. The arguments of [Ca01] can then be directly adapted to extend the main
structure results to this orbifold category. We hope to come back to deeper
aspects later. The motivation is that the natural frame for the theory of
classification of compact K\" ahler (and complex projective) manifolds includes
at least the category of orbifolds, as shown in [Ca01] by the fonctorial
decomposition of {\it special} manifolds as tower of orbifolds with either
$\kappa_+=-\infty$ or $\kappa=0$, and also, seemingly, by the minimal model
program, in which most proofs work only after the adjunction of a "boundary".
Also, fibrations enjoy in the bimeromorphic category of geometric orbifolds
extension properties not satisfied in the category of varieties without
orbifold structure, permitting to express invariants of the total space from
those of the generic fibre and of the base. For example, the natural sequence
of fundamental groups is exact there; also the total space is special if so are
the generic fibre and the base. This makes this category suitable to lift
properties from orbifolds having either $\kappa_+=-\infty$ or $\kappa=0$ to
those which are special.
| [
{
"version": "v1",
"created": "Sat, 5 May 2007 10:11:35 GMT"
},
{
"version": "v2",
"created": "Wed, 27 Jun 2007 12:03:45 GMT"
},
{
"version": "v3",
"created": "Sat, 30 Jun 2007 10:05:33 GMT"
},
{
"version": "v4",
"created": "Fri, 21 Dec 2007 15:11:16 GMT"
},
{
"version": "v5",
"created": "Fri, 3 Oct 2008 15:44:11 GMT"
},
{
"version": "v6",
"created": "Sat, 6 Dec 2008 15:01:50 GMT"
},
{
"version": "v7",
"created": "Tue, 5 May 2009 14:28:56 GMT"
},
{
"version": "v8",
"created": "Wed, 15 Jul 2009 08:55:46 GMT"
}
] | 2009-07-15T00:00:00 | [
[
"Campana",
"Frederic",
""
]
] |
0705.0738 | Damien Chablat | Damien Chablat (IRCCyN), St\'ephane Caro (IRCCyN), Emilie Bouyer
(IRCCyN) | The Optimization of a Novel Prismatic Drive | null | null | null | null | cs.RO | null | The design of a mechanical transmission taking into account the transmitted
forces is reported in this paper. This transmission is based on Slide-o-Cam, a
cam mechanism with multiple rollers mounted on a common translating follower.
The design of Slide-o-Cam, a transmission intended to produce a sliding motion
from a turning drive, or vice versa, was reported elsewhere. This transmission
provides pure-rolling motion, thereby reducing the friction of rack-and-pinions
and linear drives. The pressure angle is a relevant performance index for this
transmission because it determines the amount of force transmitted to the load
vs. that transmitted to the machine frame. To assess the transmission
capability of the mechanism, the Hertz formula is introduced to calculate the
stresses on the rollers and on the cams. The final transmission is intended to
replace the current ball-screws in the Orthoglide, a three-DOF parallel robot
for the production of translational motions, currently under development for
machining applications at Ecole Centrale de Nantes.
| [
{
"version": "v1",
"created": "Sat, 5 May 2007 10:28:22 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Chablat",
"Damien",
"",
"IRCCyN"
],
[
"Caro",
"Stéphane",
"",
"IRCCyN"
],
[
"Bouyer",
"Emilie",
"",
"IRCCyN"
]
] |
0705.0739 | Henrik Densing Petersen | Henrik Densing Petersen | Composability in a certain family of entropies | 7 pages, updated references and introduction / discussion sections.
Main text remains unchanged | null | null | null | cond-mat.stat-mech | null | It is shown that the Tsallis entropies are the only entropies of the form
$H(P)=-\sum_i f(p_i)$, with suitable assumptions on $f$, satisfying the
condition of composability.
| [
{
"version": "v1",
"created": "Sat, 5 May 2007 10:32:55 GMT"
},
{
"version": "v2",
"created": "Tue, 16 Oct 2007 13:14:27 GMT"
}
] | 2007-10-16T00:00:00 | [
[
"Petersen",
"Henrik Densing",
""
]
] |
0705.0740 | Farook Rahaman | F.Rahaman, M.Kalam and S.Chakraborty | Gravitational lensing by stable C-field wormhole | 15 pages, 3 figures. Submitted in Chin.J.phys. after minor revisions,
some references added | Chin.J.Phys.45:518,2007 | null | null | gr-qc | null | It has been recently shown that Hoyle-Narlikar's C-field theory admits
wormhole geometry. We derive the deflection angle of light rays caused by
C-field wormhole in the strong field limit approach of gravitational lensing
theory. The linearized stability of C-field wormhole under spherically
symmetric perturbations about static equilibrium is also explored.
| [
{
"version": "v1",
"created": "Sat, 5 May 2007 11:18:35 GMT"
},
{
"version": "v2",
"created": "Mon, 4 Jun 2007 09:06:05 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Rahaman",
"F.",
""
],
[
"Kalam",
"M.",
""
],
[
"Chakraborty",
"S.",
""
]
] |
0705.0741 | Khurram Shabbir | Khurram Shabbir | On the torsion of Brieskorn modules of homogeneous polynomials | null | null | null | null | math.AG | null | Let $f\in \mathbb{C}[X_1,..., X_n]$ be a homogeneous polynomial and B(f) be
the corresponding Brieskorn module. We describe the torsion of the Brieskorn
module B(f) for n=2 and show that any torsion element has order 1. For n>2, we
find some examples in which the torsion order is strictly greater than 1.
| [
{
"version": "v1",
"created": "Sat, 5 May 2007 10:59:51 GMT"
},
{
"version": "v2",
"created": "Tue, 8 May 2007 07:48:28 GMT"
},
{
"version": "v3",
"created": "Mon, 6 Aug 2007 12:47:53 GMT"
}
] | 2007-08-06T00:00:00 | [
[
"Shabbir",
"Khurram",
""
]
] |
0705.0742 | K. P.N. Murthy | V.Sundaram and K.P.N.Murthy | MIMO detection employing Markov Chain Monte Carlo | 8 pages; 3 figures | null | null | null | cs.GL | null | We propose a soft-output detection scheme for Multiple-Input-Multiple-Output
(MIMO) systems. The detector employs Markov Chain Monte Carlo method to compute
bit reliabilities from the signals received and is thus suited for coded MIMO
systems. It offers a good trade-off between achievable performance and
algorithmic complexity.
| [
{
"version": "v1",
"created": "Sat, 5 May 2007 12:04:52 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Sundaram",
"V.",
""
],
[
"Murthy",
"K. P. N.",
""
]
] |
0705.0743 | Valentin Zakharov | V.I. Zakharov | Nonperturbative physics at short distances | 15 pages, contributed to International Symposium on the Jubilee of
the Sakata Model (pnLambda50), Nagoya, Japan, Nov. 2006 | null | 10.1143/PTPS.167.105 | null | hep-ph | null | There is accumulating evidence in lattice QCD that attempts to locate
confining fields in vacuum configurations bring results explicitly depending on
tha lattice spacing (that is, ultraviolet cut off). Generically, one deals with
low-dimensional vacuum defects which occupy a vanishing fraction of the total
four-dimensional space. We review briefly existing data on the vacuum defects
and their significance for confinement and other nonperturbative phenomena. We
introduce the notion of `quantum numbers' of the defects and draw an analogy,
rather formal one, to developments which took place about 50 years ago and were
triggered by creation of the Sakata model.
| [
{
"version": "v1",
"created": "Sat, 5 May 2007 12:29:22 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Zakharov",
"V. I.",
""
]
] |
0705.0744 | Tomislav Ivezic | Tomislav Ivezi\'c | Classical and Quantum Interaction of the Dipole Revisited | 8 pages, sections are added, minor changes in the text | null | null | null | hep-th quant-ph | null | The interaction of the electric and magnetic dipole moments of a particle
with the electromagnetic field is investigated in an approach that deals with
four-dimensional (4D) geometric quantities. The new commutation relations for
the 4D orbital and intrinsic angular momentums and also for the 4D dipole
moments are introduced. The expectation value of the quantum 4-force, which
holds in any frame, is worked out in terms of them. In contrast to it the whole
calculation in [1] ([1] J. Anandan, Phys. Rev. Lett. \textbf{85}, 1354 (2000))
has been made only in the rest frame of the dipole. It is proved that, e.g.,
the expression for the 3D force $\mathbf{f}%_{S}$ in [1] is not
relativistically correct and that the quantum 4-force is not zero in the
experiments proposed in [1]. This means that the phase shifts that could be
observed in such experiments are not topological phase shifts.
| [
{
"version": "v1",
"created": "Sat, 5 May 2007 12:45:15 GMT"
},
{
"version": "v2",
"created": "Wed, 26 Sep 2007 10:40:04 GMT"
}
] | 2011-11-09T00:00:00 | [
[
"Ivezić",
"Tomislav",
""
]
] |
0705.0745 | Rigoberto Hernandez | Alex V. Popov and Rigoberto Hernandez | The ontology of temperature in nonequilibrium systems | J.Chem.Phys. (in press); 23 pages, 3 figures, 1 table | null | 10.1063/1.2743032 | null | cond-mat.stat-mech | null | The laws of thermodynamics provide a clear concept of the temperature for an
equilibrium system in the continuum limit. Meanwhile, the equipartition theorem
allows one to make a connection between the ensemble average of the kinetic
energy and the uniform temperature. When a system or its environment is far
from equilibrium, however, such an association does not necessarily apply. In
small systems, the regression hypothesis may not even apply. Herein, we show
that in small nonequilibrium systems, the regression hypothesis still holds
though with a generalized definition of the temperature. The latter must now be
defined for each such manifestation.
| [
{
"version": "v1",
"created": "Sat, 5 May 2007 12:59:58 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Popov",
"Alex V.",
""
],
[
"Hernandez",
"Rigoberto",
""
]
] |
0705.0746 | Heidi Rzehak | S. Heinemeyer, W. Hollik, H. Rzehak, G. Weiglein | The Higgs sector of the complex MSSM at two-loop order: QCD
contributions | 15 pages, 7 figures; minor changes; published version | Phys.Lett.B652:300-309,2007 | 10.1016/j.physletb.2007.07.030 | DCPT/07/34, IPPP/07/17, MPP-2007-52, PSI-PR-07-02 | hep-ph | null | Results are presented for the leading two-loop contributions of O(alpha_t
alpha_s) to the masses and mixing effects in the Higgs sector of the MSSM with
complex parameters. They are obtained in the Feynman-diagrammatic approach
using on-shell renormalization. The full dependence on all complex phases is
taken into account. The renormalization of the appropriate contributions of the
Higgs-boson sector and the scalar top and bottom sector is discussed. Our
numerical analysis for the lightest MSSM Higgs-boson mass is based on the new
two-loop corrections, supplemented by the full one-loop result. The corrections
induced by the phase variation in the scalar top sector are enhanced by the
two-loop contributions. We find that the corresponding shift in M_h1 can amount
to 5 GeV.
| [
{
"version": "v1",
"created": "Mon, 7 May 2007 16:37:36 GMT"
},
{
"version": "v2",
"created": "Fri, 16 Nov 2007 18:00:08 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Heinemeyer",
"S.",
""
],
[
"Hollik",
"W.",
""
],
[
"Rzehak",
"H.",
""
],
[
"Weiglein",
"G.",
""
]
] |
0705.0747 | David Campo | David Campo, Jens Niemeyer, and Renaud Parentani | Damped Corrections to Inflationary Spectra from a Fluctuating Cutoff | null | Phys.Rev.D76:023513,2007 | 10.1103/PhysRevD.76.023513 | null | hep-th | null | We reconsider trans-Planckian corrections to inflationary spectra by taking
into account a physical effect which has been overlooked and which could have
important consequences. We assume that the short length scale characterizing
the new physics is endowed with a finite width, the origin of which could be
found in quantum gravity. As a result, the leading corrections responsible for
superimposed osillations in the CMB temperature anisotropies are generically
damped by the blurring of the UV scale. To determine the observational
ramifications of this damping, we compare it to that which effectively occurs
when computing the angular power spectrum of temperature anisotropies. The
former gives an overall change of the oscillation amplitudes whereas the latter
depends on the angular scale. Therefore, in principle they could be
distinguished. In any case, the observation of superimposed oscillations would
place tight constraint on the variance of the UV cutoff.
| [
{
"version": "v1",
"created": "Sat, 5 May 2007 13:35:30 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Campo",
"David",
""
],
[
"Niemeyer",
"Jens",
""
],
[
"Parentani",
"Renaud",
""
]
] |
0705.0748 | Jarrod R. Hurley | Jarrod R. Hurley | Ratios of star cluster core and half-mass radii: a cautionary note on
intermediate-mass black holes in star clusters | 14 pages, 7 figures, accepted for publication in MNRAS | Mon.Not.Roy.Astron.Soc.379:93-99,2007 | 10.1111/j.1365-2966.2007.11912.x | null | astro-ph | null | There is currently much interest in the possible presence of
intermediate-mass black holes in the cores of globular clusters. Based on
theoretical arguments and simulation results it has previously been suggested
that a large core radius -- or particularly a large ratio of the core radius to
half-mass radius -- is a promising indicator for finding such a black hole in a
star cluster. In this study N-body models of 100000 stars with and without
primordial binaries are used to investigate the long-term structural evolution
of star clusters. Importantly, the simulation data is analysed using the same
processes by which structural parameters are extracted from observed star
clusters. This gives a ratio of the core and half-mass (or half-light) radii
that is directly comparable to the Galactic globular cluster sample. As a
result, it is shown that the ratios observed for the bulk of this sample can be
explained without the need for an intermediate-mass black hole. Furthermore, it
is possible that clusters with large core to half-light radius ratios harbour a
black-hole binary (comprised of stellar mass black holes) rather than a single
massive black hole. This work does not rule out the existence of
intermediate-mass black holes in the cores of at least some star clusters.
| [
{
"version": "v1",
"created": "Sat, 5 May 2007 14:09:23 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"Hurley",
"Jarrod R.",
""
]
] |
0705.0749 | Oleksiy Roslyak V | Oleksiy Roslyak and Joseph L. Birman | Evanescent quadrupole polariton | 4 pages, 3 figures; APS/PREPRINT | null | 10.1016/j.ssc.2007.10.002 | null | cond-mat.mtrl-sci | null | In the work we demonstrate the formation of new type of polariton on the
interface between a cuprous oxide slab and a polystyrene micro-sphere placed on
the slab. The evanescent field of the resonant whispering gallery mode (WGM)
has a substantial gradient, and therefore effectively couples with the
quadrupole $1S$ excitons in cuprous oxide. This evanescent polariton has a long
life-time ($1.7 ns$), which is determined only by its excitonic component. The
polariton lower branch has a well pronounced minimum. This suggests that this
excitation can be utilized for BEC. The spatial coherence of the polariton can
be improved by assembling the micro-spheres in a linear chain.
| [
{
"version": "v1",
"created": "Sat, 5 May 2007 14:32:35 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Roslyak",
"Oleksiy",
""
],
[
"Birman",
"Joseph L.",
""
]
] |
0705.0750 | Stefano Covino | S. Covino | A Closer Look at a Gamma-Ray Burst | 2 pages, 1 figure; Science perspective to Mundell et al. 2007,
Science, 315, 1822 | Science 315:1798-1799,2007 | 10.1126/science.1140172 | null | astro-ph | null | A study of gamma rays produced when stars collapse or collide reveals details
of the explosion mechanism, particularly the role of magnetic fields.
| [
{
"version": "v1",
"created": "Sat, 5 May 2007 15:00:21 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"Covino",
"S.",
""
]
] |
0705.0751 | Pere Constans | Pere Constans | Approximate textual retrieval | null | null | null | null | cs.IR cs.DL | null | An approximate textual retrieval algorithm for searching sources with high
levels of defects is presented. It considers splitting the words in a query
into two overlapping segments and subsequently building composite regular
expressions from interlacing subsets of the segments. This procedure reduces
the probability of missed occurrences due to source defects, yet diminishes the
retrieval of irrelevant, non-contextual occurrences.
| [
{
"version": "v1",
"created": "Sat, 5 May 2007 17:27:42 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Constans",
"Pere",
""
]
] |
0705.0752 | Fabio Riccioni | Fabio Riccioni, Peter West | The E_{11} origin of all maximal supergravities | 54 pages | JHEP 0707:063,2007 | 10.1088/1126-6708/2007/07/063 | KCL-MTH-07-04 | hep-th | null | Starting from the eleven dimensional E_{11} non-linear realisation of
M-theory we compute all possible forms, that is objects with totally
antisymmetrised indices, that occur in four dimensions and above as well as all
the 1-forms and 2-forms in three dimensions. In any dimension D, the D-1-forms
lead to maximal supergravity theories with cosmological constants and they are
in precise agreement with the patterns of gauging found in any dimension using
supersymmetry. The D-forms correspond to the presence of space-filling branes
which are crucial for the consistency of orientifold models and have not been
derived from an alternative approach, with the exception of the 10-dimensional
case. It follows that the gaugings of supergravities and the spacetime-filling
branes possess an eleven dimensional origin within the E_{11} formulation of
M-theory. This and previous results very strongly suggest that all the fields
in the adjoint representation of E_{11} have a physical interpretation.
| [
{
"version": "v1",
"created": "Mon, 7 May 2007 08:36:53 GMT"
}
] | 2009-04-17T00:00:00 | [
[
"Riccioni",
"Fabio",
""
],
[
"West",
"Peter",
""
]
] |
0705.0753 | Matthias Brack | Matthias Brack and Kaori Tanaka | Transcritical bifurcations in non-integrable Hamiltonian systems | LaTeX, 38 pages, 13 figures; substantially revised version v4; to be
published in Phys. Rev. E | Phys. Rev. E 77, 046205 (2008) | 10.1103/PhysRevE.77.046205 | null | nlin.CD math.DS | null | We report on transcritical bifurcations of periodic orbits in non-integrable
two-dimensional Hamiltonian systems. We discuss their existence criteria and
some of their properties using a recent mathematical description of
transcritical bifurcations in families of symplectic maps. We then present
numerical examples of transcritical bifurcations in a class of generalized
H\'enon-Heiles Hamiltonians and illustrate their stabilities and unfoldings
under various perturbations of the Hamiltonians. We demonstrate that for
Hamiltonians containing straight-line librating orbits, the transcritical
bifurcation of these orbits is the typical case which occurs also in the
absence of any discrete symmetries, while their isochronous pitchfork
bifurcation is an exception. We determine the normal forms of both types of
bifurcations and derive the uniform approximation required to include
transcritically bifurcating orbits in the semiclassical trace formula for the
density of states of the quantum Hamiltonian. We compute the coarse-grained
density of states in a specific example both semiclassically and quantum
mechanically and find excellent agreement of the results.
| [
{
"version": "v1",
"created": "Sat, 5 May 2007 16:52:59 GMT"
},
{
"version": "v2",
"created": "Thu, 18 Oct 2007 09:54:29 GMT"
},
{
"version": "v3",
"created": "Wed, 31 Oct 2007 08:34:54 GMT"
},
{
"version": "v4",
"created": "Fri, 7 Mar 2008 08:53:31 GMT"
}
] | 2008-04-14T00:00:00 | [
[
"Brack",
"Matthias",
""
],
[
"Tanaka",
"Kaori",
""
]
] |
0705.0754 | Luda Markus-Epstein | L. Markus-Epstein | Stallings' Foldings and Subgroups of Amalgams of Finite Groups | 43 pages with 14 figures | null | null | null | math.GR | null | In the 1980's Stallings showed that every finitely generated subgroup of a
free group is canonically represented by a finite minimal immersion of a
bouquet of circles. In terms of the theory of automata, this is a minimal
finite inverse automaton. This allows for the deep algorithmic theory of finite
automata and finite inverse monoids to be used to answer questions about
finitely generated subgroups of free groups.
In this paper we attempt to apply the same methods to other classes of
groups. A fundamental new problem is that the Stallings folding algorithm must
be modified to allow for ``sewing'' on relations of non-free groups. We look at
the class of groups that are amalgams of finite groups. It is known that these
groups are locally quasiconvex and thus all finitely generated subgroups are
represented by finite automata. We present an algorithm to compute such a
finite automaton and use it to solve various algorithmic problems.
| [
{
"version": "v1",
"created": "Sat, 5 May 2007 16:34:09 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Markus-Epstein",
"L.",
""
]
] |
0705.0755 | George Batrouni | K. Bouadim, N. Paris, F. Hebert, G.G. Batrouni, and R.T. Scalettar | Metallic phase in the two-dimensional ionic Hubbard model | null | Phys Rev B76, 085112 (2007). | 10.1103/PhysRevB.76.085112 | null | cond-mat.str-el | null | We investigate the phases of the ionic Hubbard model in a two-dimensional
square lattice using determinant quantum Monte Carlo (DQMC). At half-filling,
when the interaction strength or the staggered potential dominate we find Mott
and band insulators, respectively. When these two energies are of the same
order we find a metallic region. Charge and magnetic structure factors
demonstrate the presence of antiferromagnetism only in the Mott region,
although the externally imposed density modulation is present everywhere in the
phase diagram. Away from half-filling, other insulating phases are found.
Kinetic energy correlations do not give clear signals for the existence of a
bond-ordered phase.
| [
{
"version": "v1",
"created": "Sat, 5 May 2007 16:42:34 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Bouadim",
"K.",
""
],
[
"Paris",
"N.",
""
],
[
"Hebert",
"F.",
""
],
[
"Batrouni",
"G. G.",
""
],
[
"Scalettar",
"R. T.",
""
]
] |
0705.0756 | Yakov Itin | Yakov Itin (Institute of Mathematics, Hebrew University of Jerusalem) | A generalized photon propagator | null | J.Phys.A40:F737-F744,2007 | 10.1088/1751-8113/40/30/F06 | null | hep-th | null | A covariant gauge independent derivation of the generalized dispersion
relation of electromagnetic waves in a medium with local and linear
constitutive law is presented. A generalized photon propagator is derived. For
Maxwell constitutive tensor, the standard light cone structure and the standard
Feynman propagator are reinstated.
| [
{
"version": "v1",
"created": "Mon, 7 May 2007 19:34:42 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Itin",
"Yakov",
"",
"Institute of Mathematics, Hebrew University of Jerusalem"
]
] |
0705.0757 | Rainer Schiel | Rainer W. Schiel and John P. Ralston | A Pionic Hadron Explains the Muon Magnetic Moment Anomaly | 14 pages, 2 figures, revised version, accepted for publication in
Physics Letters B | Phys.Lett.B657:43-48,2007 | 10.1016/j.physletb.2007.09.040 | null | hep-ph nucl-th | null | A significant discrepancy exists between experiment and calculations of the
muon's magnetic moment. We find that standard formulas for the hadronic vacuum
polarization term have overlooked pionic states known to exist. Coulomb binding
alone guarantees $\pi^+ \pi^-$ states that quantum mechanically mix with the
$\rho$ meson. A simple 2-state mixing model explains the magnetic moment
discrepancy for a mixing angle of order $\alpha \sim 10^{-2}$. The relevant
physical state is predicted to give a tiny observable bump in the ratio R(s) of
$e^+ e^-$ annihilation at a low energy not previously searched. The burden of
proof is reversed for claims that conventional physics cannot explain the
muon's anomalous moment.
| [
{
"version": "v1",
"created": "Sat, 5 May 2007 17:30:29 GMT"
},
{
"version": "v2",
"created": "Mon, 1 Oct 2007 18:10:54 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Schiel",
"Rainer W.",
""
],
[
"Ralston",
"John P.",
""
]
] |
0705.0758 | Carlos Augusto Romero Filho | F. C. Sousa, J. B. Fonseca and C. Romero | Equivalence of three-dimensional spacetimes | 13 pages - content changes and corrected typos | Class.Quant.Grav.25:035007,2008 | 10.1088/0264-9381/25/3/035007 | null | gr-qc | null | A solution to the equivalence problem in three-dimensional gravity is given
and a practically useful method to obtain a coordinate invariant description of
local geometry is presented. The method is a nontrivial adaptation of Karlhede
invariant classification of spacetimes of general relativity. The local
geometry is completely determined by the curvature tensor and a finite number
of its covariant derivatives in a frame where the components of the metric are
constants. The results are presented in the framework of real two-component
spinors in three-dimensional spacetimes, where the algebraic classifications of
the Ricci and Cotton-York spinors are given and their isotropy groups and
canonical forms are determined. As an application we discuss Goedel-type
spacetimes in three-dimensional General Relativity. The conditions for local
space and time homogeneity are derived and the equivalence of three-dimensional
Goedel-type spacetimes is studied and the results are compared with previous
works on four-dimensional Goedel-type spacetimes.
| [
{
"version": "v1",
"created": "Sat, 5 May 2007 17:51:58 GMT"
},
{
"version": "v2",
"created": "Thu, 3 Jan 2008 18:39:06 GMT"
}
] | 2011-03-28T00:00:00 | [
[
"Sousa",
"F. C.",
""
],
[
"Fonseca",
"J. B.",
""
],
[
"Romero",
"C.",
""
]
] |
0705.0759 | Luda Markus-Epstein | L. Markus-Epstein | Algorithmic Problems in Amalgams of Finite Groups | 39 pages with 9 figures | null | null | null | math.GR | null | Geometric methods proposed by Stallings for treating finitely generated
subgroups of free groups were successfully used to solve a wide collection of
decision problems for free groups and their subgroups.
It turns out that Stallings' methods can be effectively generalized for the
class of amalgams of finite groups. In the present paper we employ subgroup
graphs constructed by the generalized Stallings' folding algorithm to solve
various algorithmic problems in amalgams of finite groups.
| [
{
"version": "v1",
"created": "Sat, 5 May 2007 18:47:29 GMT"
},
{
"version": "v2",
"created": "Mon, 2 Jul 2007 08:49:49 GMT"
}
] | 2007-07-02T00:00:00 | [
[
"Markus-Epstein",
"L.",
""
]
] |
0705.0760 | Sujay Sanghavi | Sujay Sanghavi | Equivalence of LP Relaxation and Max-Product for Weighted Matching in
General Graphs | 6 pages, 2 figures | null | null | null | cs.IT cs.AI cs.LG cs.NI math.IT | null | Max-product belief propagation is a local, iterative algorithm to find the
mode/MAP estimate of a probability distribution. While it has been successfully
employed in a wide variety of applications, there are relatively few
theoretical guarantees of convergence and correctness for general loopy graphs
that may have many short cycles. Of these, even fewer provide exact ``necessary
and sufficient'' characterizations.
In this paper we investigate the problem of using max-product to find the
maximum weight matching in an arbitrary graph with edge weights. This is done
by first constructing a probability distribution whose mode corresponds to the
optimal matching, and then running max-product. Weighted matching can also be
posed as an integer program, for which there is an LP relaxation. This
relaxation is not always tight. In this paper we show that \begin{enumerate}
\item If the LP relaxation is tight, then max-product always converges, and
that too to the correct answer. \item If the LP relaxation is loose, then
max-product does not converge. \end{enumerate} This provides an exact,
data-dependent characterization of max-product performance, and a precise
connection to LP relaxation, which is a well-studied optimization technique.
Also, since LP relaxation is known to be tight for bipartite graphs, our
results generalize other recent results on using max-product to find weighted
matchings in bipartite graphs.
| [
{
"version": "v1",
"created": "Sat, 5 May 2007 18:57:47 GMT"
}
] | 2007-07-13T00:00:00 | [
[
"Sanghavi",
"Sujay",
""
]
] |
0705.0761 | Tshilidzi Marwala | Tshilidzi Marwala and Bodie Crossingham | Bayesian Approach to Neuro-Rough Models | 24 pages, 5 figures, 1 table | null | null | null | cs.AI | null | This paper proposes a neuro-rough model based on multi-layered perceptron and
rough set. The neuro-rough model is then tested on modelling the risk of HIV
from demographic data. The model is formulated using Bayesian framework and
trained using Monte Carlo method and Metropolis criterion. When the model was
tested to estimate the risk of HIV infection given the demographic data it was
found to give the accuracy of 62%. The proposed model is able to combine the
accuracy of the Bayesian MLP model and the transparency of Bayesian rough set
model.
| [
{
"version": "v1",
"created": "Sun, 6 May 2007 22:55:58 GMT"
},
{
"version": "v2",
"created": "Wed, 9 May 2007 04:13:04 GMT"
},
{
"version": "v3",
"created": "Tue, 28 Aug 2007 09:24:46 GMT"
}
] | 2007-08-28T00:00:00 | [
[
"Marwala",
"Tshilidzi",
""
],
[
"Crossingham",
"Bodie",
""
]
] |
0705.0762 | Zhigang Han | Zhigang Han (Umass Amherst) | The bounded isometry conjecture for the Kodaira-Thurston manifold and
4-Torus | 16 pages | null | null | null | math.SG | null | The purpose of this note is to study the bounded isometry conjecture proposed
by Lalonde and Polterovich. In particular, we show that the conjecture holds
for the Kodaira-Thurston manifold with the standard symplectic form and for the
4-torus with all linear symplectic forms.
| [
{
"version": "v1",
"created": "Sat, 5 May 2007 19:14:35 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Han",
"Zhigang",
"",
"Umass Amherst"
]
] |
0705.0763 | Stefan Kimeswenger | Piet O. Schmidt (Exp. Physics, Univ. Innsbruck, Austria) Stefan
Kimeswenger (Astro- & Particle Physics, Univ. Innsbruck, Austria) Hans Ulrich
Kaeufl (ESO, Garching, Germany) | A new Generation of Spectrometer Calibration Techniques based on Optical
Frequency Combs | will be published in the proceedings of "The 2007 ESO Instrument
Calibration Workshop", Springer-Verlag series "ESO Astrophysics Symposia" | null | 10.1007/978-3-540-76963-7_55 | null | astro-ph | null | Typical astronomical spectrographs have a resolution ranging between a few
hundred to 200.000. Deconvolution and correlation techniques are being employed
with a significance down to 1/1000 th of a pixel. HeAr and ThAr lamps are
usually used for calibration in low and high resolution spectroscopy,
respectively. Unfortunately, the emitted lines typically cover only a small
fraction of the spectrometer's spectral range. Furthermore, their exact
position depends strongly on environmental conditions. A problem is the strong
intensity variation between different (intensity ratios {>300). In addition,
the brightness of the lamps is insufficient to illuminate a spectrograph via an
integrating sphere, which in turn is important to calibrate a long-slit
spectrograph, as this is the only way to assure a uniform illumination of the
spectrograph pupil.
Laboratory precision laser spectroscopy has experienced a major advance with
the development of optical frequency combs generated by pulsed femto-second
lasers. These lasers emit a broad spectrum (several hundred nanometers in the
visible and near infra-red) of equally-spaced "comb" lines with almost uniform
intensity (intensity ratios typically <10). Self-referencing of the laser
establishes a precise ruler in frequency space that can be stabilized to the
10e-18 uncertainty level, reaching absolute frequency inaccuracies at the
10e-12 level per day when using the Global Positioning System's (GPS) time
signal as the reference. The exploration of the merits of this new technology
holds the promise for broad-band, highly accurate and reproducible calibration
required for reliable operation of current and next generation astronomic
spectrometers.
| [
{
"version": "v1",
"created": "Sat, 5 May 2007 19:39:45 GMT"
}
] | 2015-05-13T00:00:00 | [
[
"Schmidt",
"Piet O.",
"",
"Exp. Physics, Univ. Innsbruck, Austria"
],
[
"Kimeswenger",
"Stefan",
"",
"Astro- & Particle Physics, Univ. Innsbruck, Austria"
],
[
"Kaeufl",
"Hans Ulrich",
"",
"ESO, Garching, Germany"
]
] |
0705.0764 | Alfredo Villanueva | Thomas Branson and Alfredo Villanueva | Symmetries in Differential Geometry: A Computational Approach to
Prolongations | 22 pages, 7 figures | null | null | null | math.DG | null | The aim of this work is to develop a systematic manner to close
overdetermined systems arising from conformal Killing tensors (CKT). The
research performs this action for 1-tensor and 2-tensors. This research makes
it possible to develop a new general method for any rank of CKT. This method
can also be applied to other types of Killing equations, as well as to
overdetermined systems constrained by some other conditions.
The major methodological apparatus of the research is a decomposition of the
section bundles where the covariant derivatives of the CKT land via generalized
gradients. This decomposition generates a tree in which each row represents a
higher derivative. After using the conformal Killing equation, just a few
components (branches) survive, which means that most of them can be expressed
in terms of lower order terms. This results in a finite number of independent
jets. Thus, any higher covariant derivative can be written in terms of these
jets.
The findings of this work are significant methodologically and, more
specifically, in the potential for the discovery of symmetries. First, this
work has uncovered a new method that could be used to close overdetermined
systems arising from conformal Killing tensors (CKT). Second, through an
application of this method, this research finds higher symmetry operators of
first and second degree, which are known by other means, for the Laplace
operator. The findings also reveal the first order symmetry operators for the
Yamabe case. Moreover, the research leads to conjectures about the second order
symmetries of the Yamabe operator.
| [
{
"version": "v1",
"created": "Sat, 5 May 2007 20:32:21 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Branson",
"Thomas",
""
],
[
"Villanueva",
"Alfredo",
""
]
] |
0705.0765 | Cesare Tronci | Darryl D. Holm, Vakhtang Putkaradze, Cesare Tronci | Geometric dissipation in kinetic equations | 7 pages, no figures. C. R. Math. Acad. Sci. Paris (in press) | null | 10.1016/j.crma.2007.07.001 | null | physics.plasm-ph nlin.AO | null | A new symplectic variational approach is developed for modeling dissipation
in kinetic equations. This approach yields a double bracket structure in phase
space which generates kinetic equations representing coadjoint motion under
canonical transformations. The Vlasov example admits measure-valued
single-particle solutions. Such solutions are reversible; and the total entropy
is a Casimir, and thus is preserved.
| [
{
"version": "v1",
"created": "Sat, 5 May 2007 20:56:30 GMT"
},
{
"version": "v2",
"created": "Tue, 21 Aug 2007 01:02:49 GMT"
}
] | 2007-08-21T00:00:00 | [
[
"Holm",
"Darryl D.",
""
],
[
"Putkaradze",
"Vakhtang",
""
],
[
"Tronci",
"Cesare",
""
]
] |
0705.0766 | S Brendle | S. Brendle and R.M. Schoen | Manifolds with 1/4-pinched Curvature are Space Forms | Final version, to appear in J. Amer. Math. Soc | null | null | null | math.DG math.AP | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Let (M,g_0) be a compact Riemannian manifold with pointwise 1/4-pinched
sectional curvatures. We show that the Ricci flow deforms g_0 to a constant
curvature metric. The proof uses the fact, also established in this paper, that
positive isotropic curvature is preserved by the Ricci flow in all dimensions.
We also rely on earlier work of Hamilton and of Bohm and Wilking.
| [
{
"version": "v1",
"created": "Sun, 6 May 2007 02:18:55 GMT"
},
{
"version": "v2",
"created": "Tue, 22 May 2007 17:56:02 GMT"
},
{
"version": "v3",
"created": "Fri, 18 Jul 2008 17:51:03 GMT"
}
] | 2008-07-18T00:00:00 | [
[
"Brendle",
"S.",
""
],
[
"Schoen",
"R. M.",
""
]
] |
0705.0767 | Shun-Pei Miao | Shun-Pei Miao | The Quantum-Corrected Fermion Mode Function during Inflation | Ph.D. thesis | null | null | null | hep-th | null | My project computed the one loop fermion self-energy for massless Dirac +
Einstein in the presence of a locally de Sitter background. I employed
dimensional regularization and obtain a fully renormalized result by absorbing
all divergences with Bogliubov, Parasiuk, Hepp and Zimmermann (BPHZ)
counterterms. An interesting technical aspect of my computation was the need
for a noninvariant counterterm, owing to the breaking of de Sitter invariance
by our gauge condition. I also solved the effective Dirac equation for massless
fermions during inflation in the simplest gauge, including all one loop
corrections from quantum gravity. At late times the result for a spatial plane
wave behaves as if the classical solution were subjected to a time-dependent
field strength renormalization of Z_2(t) = 1 - 17(4 pi) *G H^2 *ln(a) + O(G^2).
I showed that this also follows from making the Hartree approximation, although
the numerical coefficients differ.
| [
{
"version": "v1",
"created": "Sat, 5 May 2007 21:57:53 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Miao",
"Shun-Pei",
""
]
] |
0705.0768 | Jordan Bell | Leonhard Euler | A succinct method for investigating the sums of infinite series through
differential formulae | 8 pages | null | null | null | math.HO math.CA | null | Translation of "Methodus succincta summas serierum infinitarum per formulas
differentiales investigandi" (1780). Euler wants to represent some given series
of functions S(x)=X(x)+X(x+1)+X(x+2)+etc. in a different way. He writes S as a
series in derivatives of X with unknown coefficients. He makes a generating
function V(z) out of these coefficients, which is the same as a generating
function that involves the Bernoulli numbers.
| [
{
"version": "v1",
"created": "Sat, 5 May 2007 21:59:42 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Euler",
"Leonhard",
""
]
] |
0705.0769 | Jorge Cuadra | Jorge Cuadra (JILA; MPA), Sergei Nayakshin (Leicester), Fabrice
Martins (MPE) | Variable accretion and emission from the stellar winds in the Galactic
centre | MNRAS, accepted. 10 pages, 11 figures. PS version is better (Fig 11
gets blurred in PDF) | Mon.Not.Roy.Astron.Soc. 383 (2008) 458-466 | 10.1111/j.1365-2966.2007.12573.x | null | astro-ph | null | We present numerical simulations of stellar wind dynamics in the central
parsec of the Galactic centre, studying in particular the accretion of gas on
to Sgr A*, the super-massive black hole. Unlike our previous work, here we use
state-of-the-art observational data on orbits and wind properties of individual
wind-producing stars. Since wind velocities were revised upwards and non-zero
eccentricities were considered, our new simulations show fewer clumps of cold
gas and no conspicuous disc-like structure. The accretion rate is dominated by
a few close `slow wind stars' v_w < 750 km/s, and is consistent with the Bondi
estimate, but variable on time-scales of tens to hundreds of years. This
variability is due to the stochastic in-fall of cold clumps of gas, as in
earlier simulations, and to the eccentric orbits of stars. The present models
fail to explain the high luminosity of Sgr A* a few hundred years ago implied
by Integral observations, but we argue that the accretion of a cold clump with
a small impact parameter could have caused it. Finally, we show the possibility
of constraining the total mass-loss rate of the `slow wind stars' using near
infra-red observations of gas in the central few arcseconds.
| [
{
"version": "v1",
"created": "Sat, 5 May 2007 22:38:37 GMT"
},
{
"version": "v2",
"created": "Wed, 10 Oct 2007 01:47:19 GMT"
}
] | 2009-03-08T00:00:00 | [
[
"Cuadra",
"Jorge",
"",
"JILA; MPA"
],
[
"Nayakshin",
"Sergei",
"",
"Leicester"
],
[
"Martins",
"Fabrice",
"",
"MPE"
]
] |
0705.0770 | Jinwu Ye | Jinwu Ye | Elementary excitations in a supersolid | 4+ pages, 1 figures, REVTEX4. Final version published in Europhysics
Letters | EPL 82 (2008) 16001 | null | null | cond-mat.mtrl-sci | null | We study elementary low energy excitations inside a supersolid. We find that
the coupling between the longitudinal lattice vibration mode and the superfluid
mode leads to two longitudinal modes (one upper branch and one lower branch)
inside the supersolid, while the transverse modes in the supersolid stay the
same as those inside a normal solid. We also work out various experimental
signatures of these novel elementary excitations by evaluating the Debye-Waller
factor, density-density correlation, vortex loop-vertex loop interactions,
specific heat and excess entropy from the vacancies per mole.
| [
{
"version": "v1",
"created": "Sat, 5 May 2007 23:20:52 GMT"
},
{
"version": "v2",
"created": "Tue, 12 Feb 2008 15:18:25 GMT"
},
{
"version": "v3",
"created": "Thu, 21 Feb 2008 19:10:14 GMT"
},
{
"version": "v4",
"created": "Thu, 28 Feb 2008 03:16:35 GMT"
}
] | 2008-03-15T00:00:00 | [
[
"Ye",
"Jinwu",
""
]
] |
0705.0771 | Mahir S. Hussein | L. C. Chamon, M. S. Hussein and L. F. Canto | Non-local effects on the heavy-ion fusion at sub-barrier energies | 4 pages, 2 figures | Braz.J.Phys.37:1177-1180,2007 | 10.1590/S0103-97332007000700018 | null | nucl-th | null | We investigate the effect of Pauli non-locality in the heavy-ion optical
potential on sub-barrier fusion reactions. The S\~{a}o Paulo potential, which
takes into account the Pauli non-locality and has been widely used in analyzing
elastic scattering, has also recently been applied to heavy-ion fusion.
However, the approximation employed in deriving the S\~{a}o Paulo potential,
based on the Perey-Buck semi-classical treatment of neutron induced reactions,
must be assessed for charged particles tunneling through a barrier. It is the
purpose of this note to look into this question. We consider the widely studied
system $^{16}$O + $^{208}$Pb at energies that span the barrier region from 10
MeV below to 10 MeV above. It seems that the non-locality plays a minor role.
We find the S\~{a}o Paulo potential to be quite adequate throughout the region.
| [
{
"version": "v1",
"created": "Sat, 5 May 2007 23:22:47 GMT"
}
] | 2011-08-04T00:00:00 | [
[
"Chamon",
"L. C.",
""
],
[
"Hussein",
"M. S.",
""
],
[
"Canto",
"L. F.",
""
]
] |
0705.0772 | Alexander Polishchuk | Alexander Polishchuk | Fourier-stable subrings in the Chow rings of abelian varieties | 8 pages, in v.2 the order of the differential operator given by the
product is computed exactly, v.3 minor typos corrected | null | null | null | math.AG | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We study subrings in the Chow ring $\CH^*(A)_{{\Bbb Q}}$ of an abelian
variety $A$, stable under the Fourier transform with respect to an arbitrary
polarization. We prove that by taking Pontryagin products of classes of
dimension $\leq 1$ one gets such a subring. We also show how to construct
finite-dimensional Fourier-stable subrings in $\CH^*(A)_{{\Bbb Q}}$. Another
result concerns the relation between the Pontryagin product and the usual
product on the $\CH^*(A)_{{\Bbb Q}}$. We prove that the operator of the usual
product with a cycle is a differential operator with respect to the Pontryagin
product and compute its order in terms of the Beauville's decomposition of
$\CH^*(A)_{{\Bbb Q}}$.
| [
{
"version": "v1",
"created": "Sat, 5 May 2007 23:39:57 GMT"
},
{
"version": "v2",
"created": "Fri, 17 Aug 2007 18:16:57 GMT"
},
{
"version": "v3",
"created": "Thu, 17 Jul 2008 06:37:25 GMT"
}
] | 2008-07-17T00:00:00 | [
[
"Polishchuk",
"Alexander",
""
]
] |
0705.0773 | Horacio M. Pastawski | Horacio M. Pastawski | Revisiting the Fermi Golden Rule: Quantum Dynamical Phase Transition as
a Paradigm Shift | At the Frontiers of Condensed Matter III, inv. lecture Buenos Aires
2006. Physica B in press | null | 10.1016/j.physb.2007.05.024 | null | cond-mat.other | null | Classical and quantum phase transitions involve observables which are
non-analytic as functions of a controlled thermodynamical variable. As occurs
with the self-consistent Fermi Golden Rule, one condition to obtain the
discontinuous behavior is the proper evaluation of a classical or quantum
thermodynamic limit. We show that in presence of an environment, the
oscillatory dynamics of a quantum two-level system, in analogy with a classical
damped oscillator, can undergo a quantum dynamical phase transition to a
non-oscillatory phase. This is obtained from a self-consistent solution of the
Generalized Landauer Buettiker Equations, a simplified integral form of the
Keldysh formalism. I argue that working at each side of the transition implies
standing under different paradigms in the Kuhn's sense of the word. In
consequence, paradigms incommensurability obtains a sound mathematical
justification as a consequence of the non-analyticity of the observables. A
strong case is made upon the need to deepen the public's intuition and
understanding on the abrupt transition from static to dynamical friction
regimes.
Keywords: Self Consistent Fermi Golden Rule, Paradigm Shift, Quantum
Dynamical Phase Transition, Decoherence, Energy-time Wigner Function,
Dissipative Two-level system, Keldysh Formalisma, Generalized
Landauer-Buettiker Equations, Loschmidt Echo, Mesoscopic Echo, Spin Dynamics,
Solid State NMR, Dynamical Quantum Zeno Effect, Liquid Crystal NMR.
| [
{
"version": "v1",
"created": "Mon, 7 May 2007 15:19:39 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Pastawski",
"Horacio M.",
""
]
] |
0705.0774 | Christian Fr{\o}nsdal | Christian Fronsdal | Stability of Polytropes | Plain Tex, 26 pages, 6 figures | Phys.Rev.D77:104019,2008 | 10.1103/PhysRevD.77.104019 | null | gr-qc astro-ph | null | This paper is an investigation of the stability of some ideal stars. It is
in- tended as a study in General Relativity, with emphasis on the coupling to
matter, eventually aimed at a better understanding of very strong gravitational
fields and Black Holes. The work is based on an action principle for the
complete system of metric and matter fields. We propose a complete revision of
the treatment of boundary conditions. An ideal star in our terminology has
spherical symmetry and an isentropic equation of state. In our first work on
this subject it was assumed that the density vanishes beyond a finite distance
from the origin. But it is difficult to decide what the proper boundary
conditions should be and we are consequently skeptical of the concept of a
fixed boundary. In this paper we investigate the double polytrope,
characterized by a polytropic index n less than 5 in the bulk of the star and a
value larger than 5 in an outer atmosphere that extends to infinity. It has no
fixed boundary but a region of critical density where the polytropic index
changes from a value that is appropriate for the bulk of the star to a value
that provides a crude model for the atmosphere. The existence of a relation
between mass and radius is confirmed, as well as an upper limit on the mass.
The principal conclusion is that all the static configurations are stable.
| [
{
"version": "v1",
"created": "Sun, 6 May 2007 01:28:06 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Fronsdal",
"Christian",
""
]
] |
0705.0775 | R. Vikram Pandya | R. V. R. Pandya | Clarifying Einstein's First Derivation for Mass-Energy Equivalence and
Consequently Making Ives's Criticism a Void | 7 pages | null | null | null | physics.hist-ph physics.gen-ph | null | We study physical situation considered by Einstein (Ann. Physik, 17, 1905)
for his first derivation of mass-energy equivalence. Einstein introduced a
constant $C$ in his derivation and reasoning surrounding $C$ and equations
containing $C$ caused criticism by Ives. Here we clarify Einstein's derivation
and obtain a value for constant $C$. The obtained zero value for $C$ suggests
alternative explanation for Einstein's derivation and makes Ives's criticism a
void and for which details are also presented in this paper.
| [
{
"version": "v1",
"created": "Sun, 6 May 2007 01:41:29 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Pandya",
"R. V. R.",
""
]
] |
0705.0776 | Bernard Anderson II | Bernard A. Anderson | Relatively computably enumerable reals | 5 pages. Significant changes from earlier version | Archive for Mathematical Logic, Volume 50, Number 3-4, May 2011,
pp. 361-365 | 10.1007/s00153-010-0219-2 | null | math.LO | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | A real X is defined to be relatively c.e. if there is a real Y such that X is
c.e.(Y) and Y does not compute X. A real X is relatively simple and above if
there is a real Y <_T X such that X is c.e.(Y) and there is no infinite subset
Z of the complement of X such that Z is c.e.(Y). We prove that every nonempty
Pi^0_1 class contains a member which is not relatively c.e. and that every
1-generic real is relatively simple and above.
| [
{
"version": "v1",
"created": "Sun, 6 May 2007 01:59:43 GMT"
},
{
"version": "v2",
"created": "Sat, 19 Jun 2010 19:40:36 GMT"
}
] | 2011-06-14T00:00:00 | [
[
"Anderson",
"Bernard A.",
""
]
] |
0705.0777 | Ying Xu | Vladimir Korepin and Ying Xu | Binary Quantum Search | 22 pages, 3 tables | International Journal of Modern Physics B, Vol. 21, No. 31 (2007)
5187-5205 | 10.1117/12.717282 | null | quant-ph | null | Database search has wide applications and is used as a subroutine in many
important algorithms. We shall consider a database with one target item.
Quantum algorithm finds the target item in a database faster than any classical
algorithm. It frequently occurs in practice that only a portion of information
about the target item is interesting, or we need to find a group of items
sharing some common feature as the target item. This problem is in general
formulated as search for a part of the database [a block] containing the target
item, instead of the item itself. This is partial search. Partial search trades
accuracy for speed, i.e. it works faster than a full search. Partial search
algorithm was discovered by Grover and Radhakrishnan. We shall consider
optimized version of the algorithm and call it GRK. It can be applied
successively [in a sequence]. First the database is partitioned into blocks and
we use GRK to find the target block. Then this target block is partitioned into
sub-blocks and we use GRK again to find the target sub-block. [We can call it
binary quantum search.] Another possibility is to partition the database into
sub-blocks directly and use GRK to find the target sub-block in one time. In
this paper we prove that the latter is faster [makes less queries to the
oracle].
| [
{
"version": "v1",
"created": "Sun, 6 May 2007 02:01:59 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Korepin",
"Vladimir",
""
],
[
"Xu",
"Ying",
""
]
] |
0705.0778 | Scott Baldridge | Anar Akhmedov, Scott Baldridge, R. Inanc Baykur, Paul Kirk, B. Doug
Park | Simply connected minimal symplectic 4-manifolds with signature less than
--1 | 32 pages, 2 figures | null | null | null | math.GT math.SG | null | For each pair $(e,\sigma)$ of integers satisfying $2e+3\sigma\ge 0$,
$\sigma\leq -2$, and $e+\sigma\equiv 0\pmod{4}$, with four exceptions, we
construct a minimal, simply connected symplectic 4-manifold with Euler
characteristic $e$ and signature $\sigma$. We also produce simply connected,
minimal symplectic 4-manifolds with signature zero (resp. signature -1) with
Euler characteristic $4k$ (resp. $4k+1$) for all $k\ge 46$ (resp. $k\ge 49$).
| [
{
"version": "v1",
"created": "Sun, 6 May 2007 03:17:25 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Akhmedov",
"Anar",
""
],
[
"Baldridge",
"Scott",
""
],
[
"Baykur",
"R. Inanc",
""
],
[
"Kirk",
"Paul",
""
],
[
"Park",
"B. Doug",
""
]
] |
0705.0779 | Eva Y. Andrei | Xu Du, Guohong Li, Eva Y. Andrei, M. Greenblatt, P. Shuk | Ageing memory and glassiness of a driven vortex system | 16 pages, 5 figures | Nature Physics, 3, 111 (2007) | 10.1038/nphys512 | null | cond-mat.supr-con | null | Many systems in nature, glasses, interfaces and fractures being some
examples, cannot equilibrate with their environment, which gives rise to novel
and surprising behaviour such as memory effects, ageing and nonlinear dynamics.
Unlike their equilibrated counterparts, the dynamics of out-of- equilibrium
systems is generally too complex to be captured by simple macroscopic laws.
Here we investigate a system that straddles the boundary between glass and
crystal: a Bragg glass formed by vortices in a superconductor. We find that the
response to an applied force evolves according to a stretched exponential, with
the exponent reflecting the deviation from equilibrium. After the force is
removed, the system ages with time and its subsequent response time scales
linearly with its age (simple ageing), meaning that older systems are slower
than younger ones. We show that simple ageing can occur naturally in the
presence of sufficient quenched disorder. Moreover, the hierarchical
distribution of timescales, arising when chunks of loose vortices cannot move
before trapped ones become dislodged, leads to a stretched-exponential
response.
| [
{
"version": "v1",
"created": "Sun, 6 May 2007 06:09:42 GMT"
}
] | 2015-05-13T00:00:00 | [
[
"Du",
"Xu",
""
],
[
"Li",
"Guohong",
""
],
[
"Andrei",
"Eva Y.",
""
],
[
"Greenblatt",
"M.",
""
],
[
"Shuk",
"P.",
""
]
] |
0705.0780 | Kenji Bekki dr | Kenji Bekki and Masashi Chiba | Massive stars and globular cluster formation | 10 pages, 8 figures, accepted by ApJ | Astrophys.J.665:1164-1172,2007 | 10.1086/519727 | null | astro-ph | null | We first present chemodynamical simulations to investigate how stellar winds
of massive stars influence early dynamical and chemical evolution of forming
globular clusters (GCs). In our numerical models, GCs form in
turbulent,high-density giant molecular clouds (GMCs), which are embedded in a
massive dark matter halo at high redshifts. We show how high-density, compact
stellar systems are formed from GMCs influenced both by physical processes
associated with star formation and by tidal fields of their host halos. We also
show that chemical pollution of GC-forming GMCs by stellar winds from massive
stars can result in star-to-star abundance inhomogeneities among light elements
(e.g., C, N, and O) of stars in GCs. The present model with a canonical initial
mass function (IMF) also shows a C-N anticorrelation that stars with smaller
[C/Fe] have larger [N/Fe] in a GC. Although these results imply that
``self-pollution'' of GC-forming GMCs by stellar winds from massive stars can
cause abundance inhomogeneities of GCs, the present models with different
parameters and canonical IMFs can not show N-rich stars with [N/Fe] ~ 0.8
observed in some GCs (e.g., NGC 6752). We discuss this apparent failure in the
context of massive star formation preceding low-mass one within GC-forming GMCs
(``bimodal star formation scenario''). We also show that although almost all
stars (~97%) show normal He abundances (Y) of ~0.24 some stars later formed in
GMCs can have Y as high as ~0.3 in some models. The number fraction of He-rich
stars with Y >0.26 is however found to be small (~10^-3) for most models.
| [
{
"version": "v1",
"created": "Sun, 6 May 2007 05:56:18 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"Bekki",
"Kenji",
""
],
[
"Chiba",
"Masashi",
""
]
] |
0705.0781 | Tshilidzi Marwala | Jonathan M.Spiller and T. Marwala | Medical Image Segmentation and Localization using Deformable Templates | 4 pages | null | null | null | cs.CV | null | This paper presents deformable templates as a tool for segmentation and
localization of biological structures in medical images. Structures are
represented by a prototype template, combined with a parametric warp mapping
used to deform the original shape. The localization procedure is achieved using
a multi-stage, multi-resolution algorithm de-signed to reduce computational
complexity and time. The algorithm initially identifies regions in the image
most likely to contain the desired objects and then examines these regions at
progressively increasing resolutions. The final stage of the algorithm involves
warping the prototype template to match the localized objects. The algorithm is
presented along with the results of four example applications using MRI, x-ray
and ultrasound images.
| [
{
"version": "v1",
"created": "Sun, 6 May 2007 06:02:46 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Spiller",
"Jonathan M.",
""
],
[
"Marwala",
"T.",
""
]
] |
0705.0782 | David Gilbank | David G. Gilbank (1), H. K. C. Yee (1), E. Ellingson (2), M. D.
Gladders (3), L. F. Barrientos (4) and K. Blindert (1) ((1) University of
Toronto, (2) University of Colorado at Boulder, (3) University of Chicago,
(4) Universidad Catolica de Chile) | Spectroscopy of moderately high-redshift RCS-1 clusters | AJ accepted. 30 pages, 7 figures (figure 5 reduced quality) | Astron.J.134:282-293,2007 | 10.1086/518561 | null | astro-ph | null | We present spectroscopic observations of 11 moderately high-redshift (z~0.7-
1.0) clusters from the first Red-Sequence Cluster Survey (RCS-1). We find
excellent agreement between the red-sequence estimated redshift and the
spectroscopic redshift, with a scatter of 10% at z>0.7. At the high-redshift
end (z>~0.9) of the sample, we find two of the systems selected are projections
of pairs of comparably rich systems, with red-sequences too close to
discriminate in (R-z') colour. In one of these systems, the two components are
close enough to be physically associated. For a subsample of clusters with
sufficient spectroscopic members, we examine the correlation between B_gcR
(optical richness) and the dynamical mass inferred from the velocity
dispersion. We find these measurements to be compatible, within the relatively
large uncertainties, with the correlation established at lower redshift for the
X-ray selected CNOC1 clusters and also for a lower redshift sample of RCS-1
clusters. Confirmation of this and calibration of the scatter in the relation
will require larger samples of clusters at these and higher redshifts.
[abridged]
| [
{
"version": "v1",
"created": "Mon, 7 May 2007 15:56:15 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Gilbank",
"David G.",
""
],
[
"Yee",
"H. K. C.",
""
],
[
"Ellingson",
"E.",
""
],
[
"Gladders",
"M. D.",
""
],
[
"Barrientos",
"L. F.",
""
],
[
"Blindert",
"K.",
""
]
] |
0705.0783 | Stefano Buzzi | Stefano Buzzi, and H. Vincent Poor | Non-cooperative games for spreading code optimization, power control and
receiver design in wireless data networks | appeared in the Proceedings of the 13th European Wireless Conference,
Paris (France), April 2007 | null | null | null | cs.IT cs.GT math.IT | null | This paper focuses on the issue of energy efficiency in wireless data
networks through a game theoretic approach. The case considered is that in
which each user is allowed to vary its transmit power, spreading code, and
uplink receiver in order to maximize its own utility, which is here defined as
the ratio of data throughput to transmit power. In particular, the case in
which linear multiuser detectors are employed at the receiver is treated first,
and, then, the more challenging case in which non-linear decision feedback
multiuser receivers are adopted is addressed. It is shown that, for both
receivers, the problem at hand of utility maximization can be regarded as a
non-cooperative game, and it is proved that a unique Nash equilibrium point
exists. Simulation results show that significant performance gains can be
obtained through both non-linear processing and spreading code optimization; in
particular, for systems with a number of users not larger than the processing
gain, remarkable gains come from spreading code optimization, while, for
overloaded systems, the largest gainscome from the use of non-linear
processing. In every case, however, the non-cooperative games proposed here are
shown to outperform competing alternatives.
| [
{
"version": "v1",
"created": "Sun, 6 May 2007 06:49:07 GMT"
}
] | 2007-07-13T00:00:00 | [
[
"Buzzi",
"Stefano",
""
],
[
"Poor",
"H. Vincent",
""
]
] |
0705.0784 | Mishkatul Bhattacharya | M. Bhattacharya and P. Meystre | Using a Laguerre-Gaussian beam to trap and cool the rotational motion of
a mirror | New cavity design, reworked title; to appear in Phys. Rev. Lett | null | 10.1103/PhysRevLett.99.153603 | null | quant-ph | null | We show theoretically that it is possible to trap and cool the rotational
motion of a macroscopic mirror made of a perfectly reflecting spiral phase
element using orbital angular momentum transfer from a Laguerre-Gaussian
optical field. This technique offers a promising route to the placement of the
rotor in its quantum mechanical ground state in the presence of thermal noise.
It also opens up the possibility of simultaneously cooling a vibrational mode
of the same mirror. Lastly, the proposed design may serve as a sensitive
torsional balance in the quantum regime.
| [
{
"version": "v1",
"created": "Sun, 6 May 2007 07:32:13 GMT"
},
{
"version": "v2",
"created": "Sat, 22 Sep 2007 01:01:40 GMT"
}
] | 2015-05-13T00:00:00 | [
[
"Bhattacharya",
"M.",
""
],
[
"Meystre",
"P.",
""
]
] |
0705.0785 | Piotr Boronski | Piotr Boronski and Laurette S. Tuckerman | Poloidal-toroidal decomposition in a finite cylinder. II.
Discretization, regularization and validation | null | Journal of Computational Physics 227, 1544-1566 (2007) | 10.1016/j.jcp.2007.08.023 | null | math.NA physics.comp-ph | null | The Navier-Stokes equations in a finite cylinder are written in terms of
poloidal and toroidal potentials in order to impose incompressibility.
Regularity of the solutions is ensured in several ways: First, the potentials
are represented using a spectral basis which is analytic at the cylindrical
axis. Second, the non-physical discontinuous boundary conditions at the
cylindrical corners are smoothed using a polynomial approximation to a steep
exponential profile. Third, the nonlinear term is evaluated in such a way as to
eliminate singularities. The resulting pseudo-spectral code is tested using
exact polynomial solutions and the spectral convergence of the coefficients is
demonstrated. Our solutions are shown to agree with exact polynomial solutions
and with previous axisymmetric calculations of vortex breakdown and of
nonaxisymmetric calculations of onset of helical spirals. Parallelization by
azimuthal wavenumber is shown to be highly effective.
| [
{
"version": "v1",
"created": "Mon, 7 May 2007 19:17:53 GMT"
}
] | 2007-11-22T00:00:00 | [
[
"Boronski",
"Piotr",
""
],
[
"Tuckerman",
"Laurette S.",
""
]
] |
0705.0786 | Motohiko Ezawa | Motohiko Ezawa | Peculiar Band Gap Structure of Graphene Nanoribbons | 8 pages, 7 figures: Presented at 14th International Conference on
Superlattices, Nano-Structures and Nano-Devices, Istanbul, July 30-August 4
(2006); Cover picture of the proceeding | Physica Status Solidi (c) 4, No.2, 489 (2007) | 10.1002/pssc.200790003 10.1002/pssc.200673205 | null | cond-mat.mes-hall cond-mat.mtrl-sci | null | Graphene nanoribbons are quasi-one-dimensional meterials with finite width.
Characterizing a wide class of nanoribbons by edge shape and width, we make a
systematic analysis of their electronic properties. The band gap structure of
nanoribbons is shown to exhibit a valley structure with stream-like sequences
of metallic or almost metallic nanoribbons. Among them, all zigzag nanoribbons
are metallic, and armchair nanoribbons are metallic by period of 3. We find
that these stream-like sequences correspond to equi-width curves, and that the
band gap of chiral and armchair nanoribbons oscillate as a function of the
width. Furthermore a possible application of nanoribbons to nanoelectronics is
discussed.
| [
{
"version": "v1",
"created": "Sun, 6 May 2007 08:55:09 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Ezawa",
"Motohiko",
""
]
] |
0705.0787 | Parvin Moyassari | Hadi Salehi, Parvin Moyassari, Reza Rashidi | On the gravitational coupling of Hadamard states | 10 pages | null | null | null | gr-qc | null | We study the constraints imposed by the Hadamard condition on the two-point
function of local states of a scalar quantum field conformally coupled to a
gravitational background. We propose a method to assign a stress tensor to the
state-dependent part of the two point function which arises as a conserved
tensor with an anomalous trace. To characterize the local Hadamard states of
physical interest we apply a super-selection rule relating this quantum stress
tensor to the matter stress tensor of a conformal invariant gravitational model
subject to a conformal symmetry breaking term. This implies that the
determination of a Hadamard state may be considered as an integral part of its
gravitational coupling via the back-reaction effect.
| [
{
"version": "v1",
"created": "Sun, 6 May 2007 09:10:33 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Salehi",
"Hadi",
""
],
[
"Moyassari",
"Parvin",
""
],
[
"Rashidi",
"Reza",
""
]
] |
0705.0788 | Christian Roos | C. F. Roos, T. Monz, K. Kim, M. Riebe, H. Haeffner, D. F. V. James, R.
Blatt | Nonlinear coupling of continuous variables at the single quantum level | null | Phys. Rev. A 77, 040302(R) (2008) | 10.1103/PhysRevA.77.040302 | null | quant-ph | null | We experimentally investigate nonlinear couplings between vibrational modes
of strings of cold ions stored in linear ion traps. The nonlinearity is caused
by the ions' Coulomb interaction and gives rise to a Kerr-type interaction
Hamiltonian H = n_r*n_s, where n_r,n_s are phonon number operators of two
interacting vibrational modes. We precisely measure the resulting oscillation
frequency shift and observe a collapse and revival of the contrast in a Ramsey
experiment. Implications for ion trap experiments aiming at high-fidelity
quantum gate operations are discussed.
| [
{
"version": "v1",
"created": "Sun, 6 May 2007 10:24:59 GMT"
}
] | 2008-04-30T00:00:00 | [
[
"Roos",
"C. F.",
""
],
[
"Monz",
"T.",
""
],
[
"Kim",
"K.",
""
],
[
"Riebe",
"M.",
""
],
[
"Haeffner",
"H.",
""
],
[
"James",
"D. F. V.",
""
],
[
"Blatt",
"R.",
""
]
] |
0705.0789 | Parvin Moyassari | Parvin Moyassari | On the construction of the Hadamard sates in two dimensions | 10 pages | null | null | null | gr-qc | null | The two dimensional analog of the Hadamard state condition is used to specify
the local Hadamard states associated with a linear quantum field coupled to a
two dimensional gravitational background. To characterize a local Hadamard
state corresponding to a physical vacuum state, we apply a superselection rule
in which the state dependent part of the two-point function is determined in
terms of a dynamical scalar field. It implies a basic connection between the
vacuum state and a scalar field coupled to gravity. We study the
characteristics of the Hadamard vacuum state through this superselection rule
using two different background metrics, the two dimensional analog of the
schwarzschild and FRW metric.
| [
{
"version": "v1",
"created": "Sun, 6 May 2007 09:26:10 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Moyassari",
"Parvin",
""
]
] |
0705.0790 | Meng Chwan Tan | Meng-Chwan Tan | Two-Dimensional Twisted Sigma Models, the Mirror Chiral de Rham Complex,
and Twisted Generalised Mirror Symmetry | 97 pages. Companion paper to hep-th/0604179. Published version | JHEP 0707:013,2007 | 10.1088/1126-6708/2007/07/013 | null | hep-th math.AG math.QA | null | In this paper, we study the perturbative aspects of a "B-twisted"
two-dimensional $(0,2)$ heterotic sigma model on a holomorphic gauge bundle
$\mathcal E$ over a complex, hermitian manifold $X$. We show that the model can
be naturally described in terms of the mathematical theory of ``Chiral
Differential Operators". In particular, the physical anomalies of the sigma
model can be reinterpreted as an obstruction to a global definition of the
associated sheaf of vertex superalgebras derived from the free conformal field
theory describing the model locally on $X$. In addition, one can also obtain a
novel understanding of the sigma model one-loop beta function solely in terms
of holomorphic data. At the $(2,2)$ locus, one can describe the resulting
half-twisted variant of the topological B-model in terms of a $\it{mirror}$
"Chiral de Rham complex" (or CDR) defined by Malikov et al. in \cite{GMS1}. Via
mirror symmetry, one can also derive various conjectural expressions relating
the sheaf cohomology of the mirror CDR to that of the original CDR on pairs of
Calabi-Yau mirror manifolds. An analysis of the half-twisted model on a
non-K\"ahler group manifold with torsion also allows one to draw conclusions
about the corresponding sheaves of CDR (and its mirror) that are consistent
with mathematically established results by Ben-Bassat in \cite{ben} on the
mirror symmetry of generalised complex manifolds. These conclusions therefore
suggest an interesting relevance of the sheaf of CDR in the recent study of
generalised mirror symmetry.
| [
{
"version": "v1",
"created": "Sun, 6 May 2007 10:24:56 GMT"
},
{
"version": "v2",
"created": "Fri, 11 May 2007 16:41:05 GMT"
},
{
"version": "v3",
"created": "Fri, 6 Jul 2007 01:41:02 GMT"
}
] | 2010-02-03T00:00:00 | [
[
"Tan",
"Meng-Chwan",
""
]
] |
0705.0791 | Zdenka Kuncic | Zdenka Kuncic and Geoffrey V. Bicknell | Towards a New Standard Model for Black Hole Accretion | To appear in the Fifth Stromlo Symposium Proceedings special issue of
ApSS | Astrophys.Space Sci.311:127-135,2007 | 10.1007/s10509-007-9522-8 | null | astro-ph | null | We briefly review recent developments in black hole accretion disk theory,
emphasizing the vital role played by magnetohydrodynamic (MHD) stresses in
transporting angular momentum. The apparent universality of accretion-related
outflow phenomena is a strong indicator that large-scale MHD torques facilitate
vertical transport of angular momentum. This leads to an enhanced overall rate
of angular momentum transport and allows accretion of matter to proceed at an
interesting rate. Furthermore, we argue that when vertical transport is
important, the radial structure of the accretion disk is modified at small
radii and this affects the disk emission spectrum. We present a simple model
demonstrating how energetic, magnetically-driven outflows modify the emergent
disk emission spectrum with respect to that predicted by standard accretion
disk theory. A comparison of the predicted spectra against observations of
quasar spectral energy distributions suggests that mass accretion rates
inferred using the standard disk model may severely underestimate their true
values.
| [
{
"version": "v1",
"created": "Sun, 6 May 2007 09:39:23 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"Kuncic",
"Zdenka",
""
],
[
"Bicknell",
"Geoffrey V.",
""
]
] |
0705.0792 | Kenji Fukushima | Kenji Fukushima (RBRC), Kei Iida (Kochi University) | Larkin-Ovchinnikov-Fulde-Ferrell state in two-color quark matter | 10 pages, 8 figures | Phys.Rev.D76:054004,2007 | 10.1103/PhysRevD.76.054004 | RBRC-672 | hep-ph | null | We explore the phase structure of two-color and two-flavor QCD in the space
of the quark chemical potential \mu_q and the isospin chemical potential \mu_I.
Using a mean-field model we calculate the chiral and diquark condensates,
\sigma and \Delta, self-consistently. In weak coupling and in the chiral limit,
we confirm the interval of the isospin chemical potential,
0.71\Delta_0<\mu_I<0.75\Delta_0, in which a single plane-wave
Larkin-Ovchinnikov-Fulde-Ferrell (LOFF) phase is favored over isotropic
superfluidity and normal quark matter. The LOFF window becomes slightly wider
at high density. For stronger coupling with nonzero quark mass, which is
relevant to currently available numerical simulations in lattice two-color QCD,
the single plane-wave LOFF phase appears only at sufficiently high density. The
prediction obtained for the LOFF region could be tested with lattice since we
can prove that the present system is free from the fermion sign problem. We
draw the energy landscape on which local minima corresponding to the isotropic
superfluid phase and the LOFF phase and a local maximum corresponding to the
gapless phase are manifest. Our results clearly illustrate the path from the
the unstable gapless phase down to the LOFF phase.
| [
{
"version": "v1",
"created": "Sun, 6 May 2007 09:51:35 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Fukushima",
"Kenji",
"",
"RBRC"
],
[
"Iida",
"Kei",
"",
"Kochi University"
]
] |
0705.0793 | Tomaso Belloni | Tomaso Belloni (INAF-OAB), Jeroen Homan (MIT), Sara Motta (INAF-OAB,
Univ. Milano Bicocca), Eva Ratti (INAF-OAB, Univ. Milano Bicocca), Mariano
Mendez (SRON Utrecht, Univ. Amsterdam, Univ. Utrecht) | RossiXTE monitoring of 4U 1636-53: I. Long-term evolution and kHz
Quasi-Periodic Oscillations | 7 pages, 6 figures, accepted for publication on MNRAS | Mon.Not.Roy.Astron.Soc.379:247-252,2007 | 10.1111/j.1365-2966.2007.11943.x | null | astro-ph | null | We have monitored the atoll-type neutron star low-mass X-ray binary 4U
1636-53 with the Rossi X-Ray Timing Explorer (RXTE) for more than 1.5 years.
Our campaign consisted of short (~2 ks) pointings separated by two days,
regularly monitoring the spectral and timing properties of the source. During
the campaign we observed a clear long-term oscillation with a period of ~30-40
days, already seen in the light curves from the RXTE All-Sky Monitor, which
corresponded to regular transitions between the hard (island) and soft (banana)
states. We detected kHz QPOs in about a third of the observations, most of
which were in the soft (banana) state. The distribution of the frequencies of
the peak identified as the lower kHz QPO is found to be different from that
previously observed in an independent data set. This suggests that the kHz QPOs
in the system shows no intrinsically preferred frequency.
| [
{
"version": "v1",
"created": "Sun, 6 May 2007 09:54:40 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"Belloni",
"Tomaso",
"",
"INAF-OAB"
],
[
"Homan",
"Jeroen",
"",
"MIT"
],
[
"Motta",
"Sara",
"",
"INAF-OAB,\n Univ. Milano Bicocca"
],
[
"Ratti",
"Eva",
"",
"INAF-OAB, Univ. Milano Bicocca"
],
[
"Mendez",
"Mariano",
"",
"SRON Utrecht, Univ. Amsterdam, Univ. Utrecht"
]
] |
0705.0794 | Gui-Jun Ding | Gui-Jun Ding, Mu-Lin Yan | Unparticle Physics in DIS | 13 pages, 6 figures | Phys.Rev.D76:075005,2007 | 10.1103/PhysRevD.76.075005 | null | hep-ph | null | The unparticle stuff scenario related to the notrivial IR fixed point in
4D-conformal field theory is recently suggested by Georgi. We illustrate its
physical effects in Deep Inelastic Scattering (DIS) process. A possible signal
of unparticle related to parity violation asymmetry in DIS is investigated. It
is found out that the behavior of this parity violation signal is sensitive to
the value of the scale dimension $d_{\cal U}$ of unpaticle.
| [
{
"version": "v1",
"created": "Sun, 6 May 2007 09:55:06 GMT"
},
{
"version": "v2",
"created": "Wed, 9 May 2007 17:40:26 GMT"
},
{
"version": "v3",
"created": "Mon, 20 Aug 2007 17:34:21 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Ding",
"Gui-Jun",
""
],
[
"Yan",
"Mu-Lin",
""
]
] |
0705.0795 | Ruanyao Duan | Runyao Duan, Yuan Feng, Yu Xin, and Mingsheng Ying | Distinguishability of Quantum States by Separable Operations | 9 pages (in IEEE TIT format), 1 eps figure. Need IEEE.cls. Missing
Reference [18] added. A preliminary version was presented at AQIS 2007 as a
long talk. Main results unchanged | IEEE Trans. Inform. Theory, vol.55, no.3, pp.1320-1330, Mar.(2009) | 10.1109/TIT.2008.2011524 | null | quant-ph | null | We study the distinguishability of multipartite quantum states by separable
operations. We first present a necessary and sufficient condition for a finite
set of orthogonal quantum states to be distinguishable by separable operations.
An analytical version of this condition is derived for the case of $(D-1)$ pure
states, where $D$ is the total dimension of the state space under
consideration. A number of interesting consequences of this result are then
carefully investigated. Remarkably, we show there exists a large class of
$2\otimes 2$ separable operations not being realizable by local operations and
classical communication. Before our work only a class of $3\otimes 3$ nonlocal
separable operations was known [Bennett et al, Phys. Rev. A \textbf{59}, 1070
(1999)]. We also show that any basis of the orthogonal complement of a
multipartite pure state is indistinguishable by separable operations if and
only if this state cannot be a superposition of 1 or 2 orthogonal product
states, i.e., has an orthogonal Schmidt number not less than 3, thus generalize
the recent work about indistinguishable bipartite subspaces [Watrous, Phys.
Rev. Lett. \textbf{95}, 080505 (2005)]. Notably, we obtain an explicit
construction of indistinguishable subspaces of dimension 7 (or 6) by
considering a composite quantum system consisting of two qutrits (resp. three
qubits), which is slightly better than the previously known indistinguishable
bipartite subspace with dimension 8.
| [
{
"version": "v1",
"created": "Sun, 6 May 2007 10:21:39 GMT"
},
{
"version": "v2",
"created": "Tue, 21 Aug 2007 13:21:50 GMT"
},
{
"version": "v3",
"created": "Mon, 8 Oct 2007 08:53:28 GMT"
}
] | 2009-06-25T00:00:00 | [
[
"Duan",
"Runyao",
""
],
[
"Feng",
"Yuan",
""
],
[
"Xin",
"Yu",
""
],
[
"Ying",
"Mingsheng",
""
]
] |
0705.0796 | Petros Zimourtopoulos E | N. I. Yannopoulou and P. E. Zimourtopoulos | Total Differential Errors in Two-Port Network Analyser Measurements | Rejected (no reason) for publication in IET Electronics Letters - No
changes in the paper since [v1] Sun, 6 May 2007 10:34:28 GMT (257kb): [v5] =
[v4] = [v3] = [v2] = [v1] | FunkTechnikPlus # Journal, Issue 1 - Year 1, 30 September 2013,
v4, 23-30, otoiser ftp#j | null | null | physics.class-ph physics.ins-det | http://creativecommons.org/licenses/by/3.0/ | Since S-parameter measurements without uncertainty cannot claim any
credibility, the uncertainties in full two-port Vector Network Analyser (VNA)
measurements were estimated using total complex differentials (Total
Differential Errors). To express precisely a comparison relation between
complex differential errors, their differential error regions (DERs) were used.
To demonstrate the method in the most accurate case of a direct zero-length
thru, practical results are presented for commonly used Z-parameters of a
simple, two-port, DC resistive T-network, which was built and tested against
frequency with a VNA measurement system extended by two lengthy transmission
lines.
| [
{
"version": "v1",
"created": "Sun, 6 May 2007 10:34:28 GMT"
},
{
"version": "v2",
"created": "Sat, 22 Sep 2007 08:01:05 GMT"
},
{
"version": "v3",
"created": "Thu, 17 Mar 2011 17:38:20 GMT"
},
{
"version": "v4",
"created": "Sun, 20 Mar 2011 08:51:25 GMT"
},
{
"version": "v5",
"created": "Wed, 17 Oct 2012 09:07:41 GMT"
}
] | 2015-06-03T00:00:00 | [
[
"Yannopoulou",
"N. I.",
""
],
[
"Zimourtopoulos",
"P. E.",
""
]
] |
0705.0797 | Francesco Mainardi | Rudolf Gorenflo and Francesco Mainardi | Continuous time random walk, Mittag-Leffler waiting time and fractional
diffusion: mathematical aspects | 36 pages, 3 figures (5 files eps). Invited lecture by R. Gorenflo at
the 373. WE-Heraeus-Seminar on Anomalous Transport: Experimental Results and
Theoretical Challenges, Physikzentrum Bad-Honnef (Germany), 12-16 July 2006;
Chairmen: R. Klages, G. Radons and I.M. Sokolov | "Anomalous Transport: Foundations and Applications", edited by R.
Klages, G. Radons and I.M Sokolov, as Chapter 4, pp. 93-127,WILEY-VCH,
Weinheim, Germany (2008) [ISBN 978-3-5277-40722-4] | null | null | cond-mat.stat-mech cond-mat.dis-nn math-ph math.MP | null | We show the asymptotic long-time equivalence of a generic power law waiting
time distribution to the Mittag-Leffler waiting time distribution,
characteristic for a time fractional CTRW. This asymptotic equivalence is
effected by a combination of "rescaling" time and "respeeding" the relevant
renewal process followed by a passage to a limit for which we need a suitable
relation between the parameters of rescaling and respeeding. Turning our
attention to spatially 1-D CTRWs with a generic power law jump distribution,
"rescaling" space can be interpreted as a second kind of "respeeding" which
then, again under a proper relation between the relevant parameters leads in
the limit to the space-time fractional diffusion equation. Finally, we treat
the `time fractional drift" process as a properly scaled limit of the counting
number of a Mittag-Leffler renewal process.
| [
{
"version": "v1",
"created": "Sun, 6 May 2007 10:38:26 GMT"
},
{
"version": "v2",
"created": "Mon, 12 May 2008 14:31:10 GMT"
}
] | 2008-05-18T00:00:00 | [
[
"Gorenflo",
"Rudolf",
""
],
[
"Mainardi",
"Francesco",
""
]
] |
Subsets and Splits
No saved queries yet
Save your SQL queries to embed, download, and access them later. Queries will appear here once saved.