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|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
0704.3601 | Chow-Choong Ngeow | S. M. Kanbur (SUNY-Oswego), C. Ngeow (UIUC), A. Nanthakumar
(SUNY-Oswego) and R. Stevens (SUNY-Oswego) | Investigations of the Non-Linear LMC Cepheid Period-Luminosity Relation
with Testimator and Schwarz Information Criterion Methods | 9 pages, 5 figures and 3 tables, PASP accepted | null | 10.1086/519290 | null | astro-ph | null | In this paper, we investigate the linearity versus non-linearity of the Large
Magellanic Cloud (LMC) Cepheid period-luminosity (P-L) relation using two
statistical approaches not previously applied to this problem: the testimator
method and the Schwarz Information Criterion (SIC). The testimator method is
extended to multiple stages for the first time, shown to be unbiased and the
variance of the estimated slope can be proved to be smaller than the standard
slope estimated from linear regression theory. The Schwarz Information
Criterion (also known as the Bayesian Information Criterion) is more
conservative than the Akaike Information Criterion and tends to choose lower
order models. By using simulated data sets, we verify that these statistical
techniques can be used to detect intrinsically linear and/or non-linear P-L
relations. These methods are then applied to independent LMC Cepheid data sets
from the OGLE project and the MACHO project, respectively. Our results imply
that there is a change of slope in longer period ranges for all of the data
sets. This strongly supports previous results, obtained from independent
statistical tests, that the observed LMC P-L relation is non-linear with a
break period at/around 10 days.
| [
{
"version": "v1",
"created": "Thu, 26 Apr 2007 18:52:50 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Kanbur",
"S. M.",
"",
"SUNY-Oswego"
],
[
"Ngeow",
"C.",
"",
"UIUC"
],
[
"Nanthakumar",
"A.",
"",
"SUNY-Oswego"
],
[
"Stevens",
"R.",
"",
"SUNY-Oswego"
]
] |
0704.3602 | Abhik Kumar Sanyal | Abhik Kumar Sanyal | Intermediate inflation or late time acceleration? | 10 pages | Adv.High Energy Phys.2009:630414,2009 | 10.1155/2008/630414 | null | astro-ph | null | The expansion rate of `Intermediate inflation' lies between the exponential
and power law expansion but corresponding accelerated expansion does not start
at the onset of cosmological evolution. Present study of `Intermediate
inflation' reveals that it admits scaling solution and has got a natural exit
form it at a later epoch of cosmic evolution, leading to late time
acceleration. The corresponding scalar field responsible for such feature is
also found to be a tracker field for both gravity with canonical and some
non-canonical form of kinetic term. Thus the so called Intermediate inflation
should be considered as yet another dark energy model with asymptotic de-Sitter
expansion.
| [
{
"version": "v1",
"created": "Thu, 26 Apr 2007 18:49:46 GMT"
},
{
"version": "v2",
"created": "Sat, 2 Jun 2007 10:13:43 GMT"
},
{
"version": "v3",
"created": "Fri, 28 Sep 2007 11:03:45 GMT"
}
] | 2009-12-17T00:00:00 | [
[
"Sanyal",
"Abhik Kumar",
""
]
] |
0704.3603 | Elchanan Mossel | Elchanan Mossel and Allan Sly | Rapid Mixing of Gibbs Sampling on Graphs that are Sparse on Average | Corrected proof of Lemma 2.9 | null | null | null | math.PR math-ph math.CO math.MP | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | In this work we show that for every $d < \infty$ and the Ising model defined
on $G(n,d/n)$, there exists a $\beta_d > 0$, such that for all $\beta <
\beta_d$ with probability going to 1 as $n \to \infty$, the mixing time of the
dynamics on $G(n,d/n)$ is polynomial in $n$. Our results are the first
polynomial time mixing results proven for a natural model on $G(n,d/n)$ for $d
> 1$ where the parameters of the model do not depend on $n$. They also provide
a rare example where one can prove a polynomial time mixing of Gibbs sampler in
a situation where the actual mixing time is slower than $n \polylog(n)$. Our
proof exploits in novel ways the local treelike structure of Erd\H{o}s-R\'enyi
random graphs, comparison and block dynamics arguments and a recent result of
Weitz.
Our results extend to much more general families of graphs which are sparse
in some average sense and to much more general interactions. In particular,
they apply to any graph for which every vertex $v$ of the graph has a
neighborhood $N(v)$ of radius $O(\log n)$ in which the induced sub-graph is a
tree union at most $O(\log n)$ edges and where for each simple path in $N(v)$
the sum of the vertex degrees along the path is $O(\log n)$. Moreover, our
result apply also in the case of arbitrary external fields and provide the
first FPRAS for sampling the Ising distribution in this case. We finally
present a non Markov Chain algorithm for sampling the distribution which is
effective for a wider range of parameters. In particular, for $G(n,d/n)$ it
applies for all external fields and $\beta < \beta_d$, where $d \tanh(\beta_d)
= 1$ is the critical point for decay of correlation for the Ising model on
$G(n,d/n)$.
| [
{
"version": "v1",
"created": "Thu, 26 Apr 2007 18:56:41 GMT"
},
{
"version": "v2",
"created": "Tue, 1 May 2007 16:00:18 GMT"
},
{
"version": "v3",
"created": "Thu, 29 Jan 2009 18:49:00 GMT"
}
] | 2009-01-29T00:00:00 | [
[
"Mossel",
"Elchanan",
""
],
[
"Sly",
"Allan",
""
]
] |
0704.3604 | Remco Scheepmaker | R. A. Scheepmaker, M. R. Haas, M. Gieles, N. Bastian, S. S. Larsen, H.
J. G. L. M. Lamers | ACS imaging of star clusters in M51. I. Identification and radius
distribution | 17 pages, 23 figures. Accepted for publication in A&A | null | 10.1051/0004-6361:20077511 | null | astro-ph | null | We use HST/ACS observations of the spiral galaxy M51 in F435W, F555W and
F814W to select a large sample of star clusters with accurate effective radius
measurements in an area covering the complete disc of M51. We present the
dataset and study the radius distribution and relations between radius, colour,
arm/interarm region, galactocentric distance, mass and age. We select a sample
of 7698 (F435W), 6846 (F555W) and 5024 (F814W) slightly resolved clusters and
derive their effective radii by fitting the spatial profiles with analytical
models convolved with the point spread function. The radii of 1284 clusters are
studied in detail. We find cluster radii between 0.5 and ~10 pc, and one
exceptionally large cluster candidate with a radius of 21.6 pc. The median
radius is 2.1 pc. We find 70 clusters in our sample which have colours
consistent with being old GC candidates and we find 6 new "faint fuzzy"
clusters in, or projected onto, the disc of M51. The radius distribution can
not be fitted with a power law, but a log-normal distribution provides a
reasonable fit to the data. This indicates that shortly after the formation of
the clusters from a fractal gas, their radii have changed in a non-uniform way.
We find an increase in radius with colour as well as a higher fraction of
redder clusters in the interarm regions, suggesting that clusters in spiral
arms are more compact. We find a correlation between radius and galactocentric
distance which is considerably weaker than the observed correlation for old
Milky Way GCs. We find weak relations between cluster luminosity and radius,
but we do not observe a correlation between cluster mass and radius.
| [
{
"version": "v1",
"created": "Thu, 26 Apr 2007 19:16:15 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Scheepmaker",
"R. A.",
""
],
[
"Haas",
"M. R.",
""
],
[
"Gieles",
"M.",
""
],
[
"Bastian",
"N.",
""
],
[
"Larsen",
"S. S.",
""
],
[
"Lamers",
"H. J. G. L. M.",
""
]
] |
0704.3605 | Mustafa Sarisaman | Mustafa Sarisaman | Pseudoduality and Conserved Currents in Sigma Models | 15 pages, discussion section added | Mod.Phys.Lett.A24:123-134,2009 | 10.1142/S021773230902876X | null | hep-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We discuss the current conservation laws in sigma models based on a compact
Lie groups of the same dimensionality and connected to each other via
pseudoduality transformations in two dimensions. We show that pseudoduality
transformations induce an infinite number of nonlocal conserved currents on the
pseudodual manifold.
| [
{
"version": "v1",
"created": "Thu, 26 Apr 2007 19:02:55 GMT"
},
{
"version": "v2",
"created": "Tue, 27 Jan 2009 05:24:14 GMT"
}
] | 2009-02-10T00:00:00 | [
[
"Sarisaman",
"Mustafa",
""
]
] |
0704.3606 | John Ward Mr | Tapan Naskar and John Ward | Type I singularities and the Phantom Menace | More references added. Final PRD version | Phys.Rev.D76:063514,2007 | 10.1103/PhysRevD.76.063514 | null | gr-qc hep-ph | null | We consider the future dynamics of a transient phantom dominated phase of the
universe in LQC and in the RS braneworld, which both have a non-standard
Friedmann equation. We find that for a certain class of potentials, the Hubble
parameter oscillates with simple harmonic motion in the LQC case and therefore
avoids any future singularity. For more general potentials we find that damping
effects eventually lead to the Hubble parameter becoming constant. On the other
hand in the braneworld case we find that although the type I singularity can be
avoided, the scale factor still diverges at late times.
| [
{
"version": "v1",
"created": "Thu, 26 Apr 2007 19:07:10 GMT"
},
{
"version": "v2",
"created": "Wed, 2 May 2007 12:20:26 GMT"
},
{
"version": "v3",
"created": "Tue, 22 May 2007 10:22:39 GMT"
},
{
"version": "v4",
"created": "Thu, 11 Oct 2007 21:15:08 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Naskar",
"Tapan",
""
],
[
"Ward",
"John",
""
]
] |
0704.3607 | Debora Peres Menezes Menezes | C. Providencia, D.P. Menezes, L. Brito, Ph. Chomaz | Low density expansion and isospin dependence of nuclear energy
functional: comparison between relativistic and Skyrme models | 16 pages,6 figures,5 tables | Phys.Rev.C76:044316,2007 | 10.1103/PhysRevC.76.044316 | null | nucl-th | null | In the present work we take the non relativistic limit of relativistic models
and compare the obtained functionals with the usual Skyrme parametrization.
Relativistic models with both constant couplings and with density dependent
couplings are considered. While some models present very good results already
at the lowest order in the density, models with non-linear terms only reproduce
the energy functional if higher order terms are taken into account in the
expansion.
| [
{
"version": "v1",
"created": "Thu, 26 Apr 2007 19:27:41 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Providencia",
"C.",
""
],
[
"Menezes",
"D. P.",
""
],
[
"Brito",
"L.",
""
],
[
"Chomaz",
"Ph.",
""
]
] |
0704.3608 | Leonid Levitov | D. A. Abanin and L. S. Levitov | Quantized Transport in Graphene p-n Junctions in Magnetic Field | 4 pages, 3 figures, available online at:
http://www.sciencemag.org/cgi/content/abstract/1144672 | Science 317, 641 (2007), originally published in Science Express
on 28 June 2007 | 10.1126/science.1144672 | null | cond-mat.mes-hall cond-mat.str-el | null | Recent experimental work on locally gated graphene layers resulting in p-n
junctions have revealed quantum Hall effect in their transport behavior. We
explain the observed conductance quantization which is fractional in the
bipolar regime and integer in the unipolar regime in terms of quantum Hall edge
modes propagating along and across the p-n interface. In the bipolar regime the
electron and hole modes can mix at the p-n boundary, leading to current
partition and quantized shot noise plateaus similar to those of conductance,
while in the unipolar regime transport is noiseless. These quantum Hall
phenomena reflect the massless Dirac character of charge carriers in graphene,
with particle-hole interplay manifest in mode mixing and noise in the bipolar
regime.
| [
{
"version": "v1",
"created": "Thu, 26 Apr 2007 19:47:14 GMT"
},
{
"version": "v2",
"created": "Thu, 26 Apr 2007 20:23:47 GMT"
},
{
"version": "v3",
"created": "Sat, 5 May 2007 03:51:05 GMT"
},
{
"version": "v4",
"created": "Sat, 30 Jun 2007 12:07:13 GMT"
}
] | 2007-08-07T00:00:00 | [
[
"Abanin",
"D. A.",
""
],
[
"Levitov",
"L. S.",
""
]
] |
0704.3609 | Jiasheng Huang | J.-S. Huang (1) M. L. N. Ashby (1) P. Barmby (1) M. Brodwin (2) M. J.
I. Brown (3) N. Caldwell (1) R. J. Cool (4) P. Eisenhardt (2) D. Eisenstein
(4) G. G. Fazio (1) E. Le Floc'h (4) P. Green (1) C. S. Kochanek (6) N. Y. Lu
(5) M. A. Pahre (1) D. Rigopoulou (7) J. L. Rosenberg (1,8) H. A. Smith (1)
Z. Wang (1) C. N. A. Willmer (4) and S. P. Willner (1) ((1) SAO, (2) JPL, (3)
Monash Univ. Australia, (4) Univ. of Arizona, (5)SSC, (6) Ohio State Univ.,
(7)Oxford Univ. UK, (8)George Mason Univ.) | The Local Galaxy 8 micron Luminosity Function | 32 pages, 12 Figures (Fig. 1, Fig. 2, and Fig. 4 are JPEG files),
accepted for publication in ApJ | Astrophys.J.664:840-849,2007 | 10.1086/519241 | null | astro-ph | null | A SST survey in the NOAO Deep-Wide Field in Bo\"otes provides a complete,
8-micron-selected sample of galaxies to a limiting (Vega) magnitude of 13.5. In
the 6.88 deg$^2$ field sampled, 79% of the 4867 galaxies have spectroscopic
redshifts, allowing an accurate determination of the local (z<0.3) galaxy
luminosity function. Stellar and dust emission can be separated on the basis of
observed galaxy colors. Dust emission (mostly PAH) accounts for 80% of the 8
micron luminosity, stellar photospheres account for 19%, and AGN emission
accounts for roughly 1 %. A sub-sample of the 8 micron-selected galaxies have
blue, early-type colors, but even most of these have significant PAH emission.
The luminosity functions for the total 8 micron luminosity and for the dust
emission alone are both well fit by Schechter functions. For the 8 micron
luminosity function, the characteristic luminosity is \nu L_{\nu}^*(8.0
\micron) = 1.8 \times 10^{10}$ \Lsun while for the dust emission alone it is
1.6 x 10^{10}$ \Lsun\null. The average 8 \micron luminosity density at z<0.3 is
3.1 x 10^7 \Lsun Mpc^{-3}, and the average luminosity density from dust alone
is 2.5 x 10^7 \Lsun Mpc^{-3}. This luminos ity arises predominantly from
galaxies with 8 \micron luminosities ($\nu L_{\nu}$) between $2\times 10^9$ and
$2 x 10^{10}$ \Lsun, i.e., normal galaxies, not LIRGs or ULIRGs.
| [
{
"version": "v1",
"created": "Thu, 26 Apr 2007 19:48:24 GMT"
},
{
"version": "v2",
"created": "Thu, 26 Apr 2007 20:23:15 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"Huang",
"J. -S.",
""
],
[
"Ashby",
"M. L. N.",
""
],
[
"Barmby",
"P.",
""
],
[
"Brodwin",
"M.",
""
],
[
"Brown",
"M. J. I.",
""
],
[
"Caldwell",
"N.",
""
],
[
"Cool",
"R. J.",
""
],
[
"Eisenhardt",
"P.",
""
],
[
"Eisenstein",
"D.",
""
],
[
"Fazio",
"G. G.",
""
],
[
"Floc'h",
"E. Le",
""
],
[
"Green",
"P.",
""
],
[
"Kochanek",
"C. S.",
""
],
[
"Lu",
"N. Y.",
""
],
[
"Pahre",
"M. A.",
""
],
[
"Rigopoulou",
"D.",
""
],
[
"Rosenberg",
"J. L.",
""
],
[
"Smith",
"H. A.",
""
],
[
"Wang",
"Z.",
""
],
[
"Willmer",
"C. N. A.",
""
],
[
"Willner",
"S. P.",
""
]
] |
0704.3610 | Akinori Tanaka | Akinori Tanaka | d-Wave Pairing State in Terms of the Zhang-Rice Singlets | 19 pages, 3 figures;In Verson 2, section 'Summary and Remarks' has
been added, typos have been corrected, and some minor changes have been made | null | 10.1088/1751-8113/40/34/002 | null | cond-mat.str-el cond-mat.supr-con | null | In cuprate superconductors doping is believed to create holes on the O-sites,
which couple antiferromagnetically with holes on the Cu-sites to form the
so-called Zhang-Rice singlets. Here we study a d-wave pairing state based on
the Zhang-Rice singlet states. Upper and lower bounds of an off-diagonal
long-range order parameter with d-wave symmetry for this state are estimated.
We also introduce a concrete model with on-site Coulomb repulsion and kinds of
antiferromagnetic interactions whose ground state is this d-wave pairing state.
| [
{
"version": "v1",
"created": "Thu, 26 Apr 2007 23:44:17 GMT"
},
{
"version": "v2",
"created": "Tue, 17 Jul 2007 10:01:05 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Tanaka",
"Akinori",
""
]
] |
0704.3611 | Samir Salim | Samir Salim, R. Michael Rich, St\'ephane Charlot, Jarle Brinchmann,
Benjamin D. Johnson, David Schiminovich, Mark Seibert, Ryan Mallery, Timothy
M. Heckman, Karl Forster, Peter G. Friedman, D. Christopher Martin, Patrick
Morrissey, Susan G. Neff, Todd Small, Ted K. Wyder, Luciana Bianchi, Jose
Donas, Young-Wook Lee, Barry F. Madore, Bruno Milliard, Alex S. Szalay, Barry
Y. Welsh and Sukyoung K. Yi | UV Star Formation Rates in the Local Universe | Accepted for publication in ApJ (Special GALEX Supplement issue - Dec
2007). v2: Typo in Eq. 2 corrected | Astrophys.J.Suppl.173:267-292,2007 | 10.1086/519218 | null | astro-ph | null | We measure star formation rates of ~50,000 optically-selected galaxies in the
local universe (z~0.1), spanning a range from gas-rich dwarfs to massive
ellipticals. We obtain dust-corrected SFRs by fitting the GALEX (UV) and SDSS
(optical) photometry to a library of population synthesis models that include
dust attenuation. For star-forming galaxies, our UV-based SFRs compare
remarkably well with those derived from SDSS H alpha. Deviations from perfect
agreement between these two methods are due to differences in the dust
attenuation estimates. In contrast to H alpha, UV provides reliable SFRs for
galaxies with weak or no H alpha emission, and where H alpha is contaminated
with an emission from an AGN. We use full-SED SFRs to calibrate a simple
prescription that uses GALEX UV magnitudes to produce good SFRs for normal
star-forming galaxies. The specific SFR is considered as a function of stellar
mass for (1) star-forming galaxies with no AGN, (2) those hosting an AGN, and
for (3) galaxies without H alpha emission. We find that the three have distinct
star formation histories, with AGN lying intermediate between the star-forming
and the quiescent galaxies. Normal star forming galaxies (without an AGN) lie
on a relatively narrow linear sequence. Remarkably, galaxies hosting a strong
AGN appear to represent the massive continuation of this sequence. Weak AGN,
while also massive, have lower SFR, sometimes extending to the realm of
quiescent galaxies. We propose an evolutionary sequence for massive galaxies
that smoothly connects normal star-forming galaxies to quiescent (red sequence)
galaxies via strong and weak AGN. We confirm that some galaxies with no H alpha
emission show signs of SF in the UV. We derive a UV-based cosmic SFR density at
z=0.1 with smaller total error than previous measurements (abridged).
| [
{
"version": "v1",
"created": "Thu, 26 Apr 2007 20:15:37 GMT"
},
{
"version": "v2",
"created": "Mon, 7 May 2007 22:44:39 GMT"
}
] | 2009-10-05T00:00:00 | [
[
"Salim",
"Samir",
""
],
[
"Rich",
"R. Michael",
""
],
[
"Charlot",
"Stéphane",
""
],
[
"Brinchmann",
"Jarle",
""
],
[
"Johnson",
"Benjamin D.",
""
],
[
"Schiminovich",
"David",
""
],
[
"Seibert",
"Mark",
""
],
[
"Mallery",
"Ryan",
""
],
[
"Heckman",
"Timothy M.",
""
],
[
"Forster",
"Karl",
""
],
[
"Friedman",
"Peter G.",
""
],
[
"Martin",
"D. Christopher",
""
],
[
"Morrissey",
"Patrick",
""
],
[
"Neff",
"Susan G.",
""
],
[
"Small",
"Todd",
""
],
[
"Wyder",
"Ted K.",
""
],
[
"Bianchi",
"Luciana",
""
],
[
"Donas",
"Jose",
""
],
[
"Lee",
"Young-Wook",
""
],
[
"Madore",
"Barry F.",
""
],
[
"Milliard",
"Bruno",
""
],
[
"Szalay",
"Alex S.",
""
],
[
"Welsh",
"Barry Y.",
""
],
[
"Yi",
"Sukyoung K.",
""
]
] |
0704.3612 | Yuji Okawa | Yuji Okawa (DESY) | Real analytic solutions for marginal deformations in open superstring
field theory | The Seitaro Nakamura Prize awarded, 16 pages, no figures; v2: a note
on different conventions for the conjugation associated with the reality
condition added, references added, minor changes | JHEP0709:082,2007 | 10.1088/1126-6708/2007/09/082 | DESY 07-056 | hep-th | null | We construct analytic solutions for marginal deformations satisfying the
reality condition in open superstring field theory formulated by Berkovits when
operator products made of the marginal operator and the associated
superconformal primary field are regular. Our strategy is based on the recent
observation by Erler that the problem of finding solutions for marginal
deformations in open superstring field theory can be reduced to a problem in
the bosonic theory of finding a finite gauge parameter for a certain pure-gauge
configuration labeled by the parameter of the marginal deformation. We find a
gauge transformation generated by a real gauge parameter which infinitesimally
changes the deformation parameter and construct a finite gauge parameter by its
path-ordered exponential. The resulting solution satisfies the reality
condition by construction.
| [
{
"version": "v1",
"created": "Fri, 27 Apr 2007 17:00:26 GMT"
},
{
"version": "v2",
"created": "Thu, 6 Sep 2007 15:13:44 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Okawa",
"Yuji",
"",
"DESY"
]
] |
0704.3613 | Chang-Soon Park | Hirosi Ooguri, Yutaka Ookouchi and Chang-Soon Park | Metastable Vacua in Perturbed Seiberg-Witten Theories | 22 pages, 4 figures; adding chiral ring arguments in appendix B.1 | Adv.Theor.Math.Phys.12:405-427,2008 | null | CALT-68-2646, UT-07-14 | hep-th hep-ph | null | We show that, for a generic choice of a point on the Coulomb branch of any
N=2 supersymmetric gauge theory, it is possible to find a superpotential
perturbation which generates a metastable vacuum at the point. For theories
with SU(N) gauge group, such a superpotential can be expressed as a sum of
single-trace terms for N=2 and 3. If the metastable point is chosen at the
origin of the moduli space, we can show that the superpotential can be a
single-trace operator for any N. In both cases, the superpotential is a
polynomial of degree 3N of the vector multiplet scalar field.
| [
{
"version": "v1",
"created": "Fri, 27 Apr 2007 19:10:57 GMT"
},
{
"version": "v2",
"created": "Sat, 2 Jun 2007 05:19:54 GMT"
}
] | 2009-09-17T00:00:00 | [
[
"Ooguri",
"Hirosi",
""
],
[
"Ookouchi",
"Yutaka",
""
],
[
"Park",
"Chang-Soon",
""
]
] |
0704.3614 | Matthew Becker | M. R. Becker, T.A. McKay, B. Koester, R. H. Wechsler, E. Rozo, A.
Evrard, D. Johnston, E. Sheldon, J. Annis, E. Lau, R. Nichol, C. Miller | The Mean and Scatter of the Velocity Dispersion-Optical Richness
Relation for maxBCG Galaxy Clusters | 25 pages, 15 figures, 2 tables, published in ApJ | Astrophys.J.669:905-928,2007 | 10.1086/521920 | null | astro-ph | null | The distribution of galaxies in position and velocity around the centers of
galaxy clusters encodes important information about cluster mass and structure.
Using the maxBCG galaxy cluster catalog identified from imaging data obtained
in the Sloan Digital Sky Survey, we study the BCG-galaxy velocity correlation
function. By modeling its non-Gaussianity, we measure the mean and scatter in
velocity dispersion at fixed richness. The mean velocity dispersion increases
from 202+/-10 km/s for small groups to more than 854+/-102 km/s for large
clusters. We show the scatter to be at most 40.5+/-3.5%, declining to
14.9+/-9.4% in the richest bins. We test our methods in the C4 cluster catalog,
a spectroscopic cluster catalog produced from the Sloan Digital Sky Survey DR2
spectroscopic sample, and in mock galaxy catalogs constructed from N-body
simulations. Our methods are robust, measuring the scatter to well within
one-sigma of the true value, and the mean to within 10%, in the mock catalogs.
By convolving the scatter in velocity dispersion at fixed richness with the
observed richness space density function, we measure the velocity dispersion
function of the maxBCG galaxy clusters. Although velocity dispersion and
richness do not form a true mass-observable relation, the relationship between
velocity dispersion and mass is theoretically well characterized and has low
scatter. Thus our results provide a key link between theory and observations up
to the velocity bias between dark matter and galaxies.
| [
{
"version": "v1",
"created": "Thu, 26 Apr 2007 20:02:18 GMT"
},
{
"version": "v2",
"created": "Fri, 19 Oct 2007 03:19:58 GMT"
}
] | 2010-11-11T00:00:00 | [
[
"Becker",
"M. R.",
""
],
[
"McKay",
"T. A.",
""
],
[
"Koester",
"B.",
""
],
[
"Wechsler",
"R. H.",
""
],
[
"Rozo",
"E.",
""
],
[
"Evrard",
"A.",
""
],
[
"Johnston",
"D.",
""
],
[
"Sheldon",
"E.",
""
],
[
"Annis",
"J.",
""
],
[
"Lau",
"E.",
""
],
[
"Nichol",
"R.",
""
],
[
"Miller",
"C.",
""
]
] |
0704.3615 | Robin Blume-Kohout | Robin Blume-Kohout and Wojciech H.Zurek | Quantum Darwinism in quantum Brownian motion: the vacuum as a witness | 5 pages | Phys.Rev.Lett.101:240405,2008 | 10.1103/PhysRevLett.101.240405 | null | quant-ph cond-mat.mes-hall hep-th | null | We study quantum Darwinism -- the redundant recording of information about a
decohering system by its environment -- in zero-temperature quantum Brownian
motion. An initially nonlocal quantum state leaves a record whose redundancy
increases rapidly with its spatial extent. Significant delocalization (e.g., a
Schroedinger's Cat state) causes high redundancy: many observers can measure
the system's position without perturbing it. This explains the objective (i.e.
classical) existence of einselected, decoherence-resistant pointer states of
macroscopic objects.
| [
{
"version": "v1",
"created": "Thu, 26 Apr 2007 20:23:24 GMT"
}
] | 2009-01-09T00:00:00 | [
[
"Blume-Kohout",
"Robin",
""
],
[
"Zurek",
"Wojciech H.",
""
]
] |
0704.3616 | Claudio Castelnovo | C. Castelnovo (1), and C. Chamon (2) ((1) Oxford University, (2)
Boston University) | Entanglement and topological entropy of the toric code at finite
temperature | (15 pages, 5 figures) v2: updated references and acknowledgments | Phys. Rev. B 76, 184442 (2007) | 10.1103/PhysRevB.76.184442 | null | cond-mat.str-el quant-ph | null | We calculate exactly the von Neumann and topological entropies of the toric
code as a function of system size and temperature. We do so for systems with
infinite energy scale separation between magnetic and electric excitations, so
that the magnetic closed loop structure is fully preserved while the electric
loop structure is tampered with by thermally excited electric charges. We find
that the entanglement entropy is a singular function of temperature and system
size, and that the limit of zero temperature and the limit of infinite system
size do not commute. From the entanglement entropy we obtain the topological
entropy, which is shown to drop to half its zero-temperature value for any
infinitesimal temperature in the thermodynamic limit, and remains constant as
the temperature is further increased. Such discontinuous behavior is replaced
by a smooth decreasing function in finite-size systems. If the separation of
energy scales in the system is large but finite, we argue that our results hold
at small enough temperature and finite system size, and a second drop in the
topological entropy should occur as the temperature is raised so as to disrupt
the magnetic loop structure by allowing the appearance of free magnetic
charges. We interpret our results as an indication that the underlying magnetic
and electric closed loop structures contribute equally to the topological
entropy (and therefore to the topological order) in the system. Since each loop
structure \emph{per se} is a classical object, we interpret the quantum
topological order in our system as arising from the ability of the two
structures to be superimposed and appear simultaneously.
| [
{
"version": "v1",
"created": "Fri, 27 Apr 2007 01:56:24 GMT"
},
{
"version": "v2",
"created": "Thu, 1 Nov 2007 18:01:09 GMT"
}
] | 2007-11-30T00:00:00 | [
[
"Castelnovo",
"C.",
""
],
[
"Chamon",
"C.",
""
]
] |
0704.3617 | V\'ictor Manuel Mu\~noz Mar\'in | V\'ictor M. Mu\~noz Mar\'in, Rosa M. Gonz\'alez Delgado, Henrique R.
Schmitt, Roberto Cid Fernandes, Enrique P\'erez, Thaisa Storchi-Bergmann, Tim
Heckman, Claus Leitherer | An Atlas of the circumnuclear regions of 75 Seyfert galaxies in the
near-UV with HST Advanced Camera for Surveys | Accepted for publication in AJ, 58 pages, 20 figures. High-resolution
figures for all the objects are available at
http://www.iaa.es/~manuel/publications/paper01.html | Astron.J.134:648-667,2007 | 10.1086/519448 | null | astro-ph | null | We present an atlas of the central regions of 75 Seyfert galaxies imaged in
the near-UV with the Advanced Camera for Surveys of the Hubble Space Telescope
at an average resolution of ~10pc. These data complement archival high
resolution data from the Space Telescope at optical and near-IR wavelengths,
creating an extremely valuable dataset for astronomers with a broad range of
scientific interests. Our goal is to investigate the nature of the near-UV
light in these objects, its relation to the circumnuclear starburst phenomenon,
and the connection of this to the evolution and growth of the galaxy bulge and
central black hole. In this paper, we describe the near-UV morphology of the
objects and characterize the near-UV emission. We estimate the size and the
luminosity of the emitting regions and extract the luminosity profile. We also
determine the presence of unresolved compact nuclei. In addition, the
circumnuclear stellar cluster population is identified, and the contribution of
the stellar clusters to the total light, at this wavelength, is estimated. The
size of the sample allows us to draw robust statistical conclusions. We find
that {Seyfert 1} galaxies are completely dominated by its bright and compact
nucleus, that remains point-like at this resolution, while we find almost no
unresolved nucleus in Seyfert 2. The Seyfert types 1 and 2 are quite segregated
in an asymmetry vs compactness plot. Stellar clusters are found somewhat more
frequently in Sy2 (in ~70% of the galaxies) than in Sy1 (~57%), and contribute
more to the total light in Sy2, but this two differences seem to be mostly due
to the large contribution of the compact nucleus in Sy1, as the luminosity
distribution of the clusters is similar in both Sy types.
| [
{
"version": "v1",
"created": "Thu, 26 Apr 2007 20:09:27 GMT"
}
] | 2016-08-14T00:00:00 | [
[
"Marín",
"Víctor M. Muñoz",
""
],
[
"Delgado",
"Rosa M. González",
""
],
[
"Schmitt",
"Henrique R.",
""
],
[
"Fernandes",
"Roberto Cid",
""
],
[
"Pérez",
"Enrique",
""
],
[
"Storchi-Bergmann",
"Thaisa",
""
],
[
"Heckman",
"Tim",
""
],
[
"Leitherer",
"Claus",
""
]
] |
0704.3618 | Tapas Kumar Das | Tapas Kumar Das | Astrophysical Accretion as an Analogue Gravity Phenomena | 56 pages, 11 figures, revtex4. Send email request to the author for
high resolution version of the manuscript | null | null | null | astro-ph gr-qc | null | In recent years, strong analogies have been established between the physics
of acoustic perturbations in an inhomogeneous dynamical fluid system, and some
kinematic features of space-time in general relativity. An effective metric,
referred to as the `acoustic metric', which describes the geometry of the
manifold in which acoustic perturbations propagate, can be constructed. This
effective geometry can capture the properties of curved space-time in general
relativity. Physical models constructed utilizing such analogies are called
`analogue gravity models'. Classical analogue gravity effect may be observed
when acoustic perturbations propagate through a inhomogeneous transonic
classical fluid. The acoustic horizon, which resembles a black hole event
horizon in many ways, is generated at the transonic point in the fluid flow.
The acoustic horizon is essentially a null hyper surface, generators of which
are the acoustic null geodesics, i.e. the phonons. The acoustic horizon emits
acoustic radiation with quasi thermal phonon spectra, which is analogous to the
actual Hawking radiation. The temperature of the radiation emitted from the
acoustic horizon is referred to as the analogue Hawking temperature.
It has been demonstrated that, in general, the transonic accretion in
astrophysics can be considered as an example of the classical analogue gravity
model naturally found in the Universe.
| [
{
"version": "v1",
"created": "Thu, 26 Apr 2007 20:10:24 GMT"
}
] | 2007-06-27T00:00:00 | [
[
"Das",
"Tapas Kumar",
""
]
] |
0704.3619 | Marcus Kaiser | Luciano da F Costa, Marcus Kaiser, Claus C Hilgetag | Predicting the connectivity of primate cortical networks from
topological and spatial node properties | null | BMC Systems Biology 2007, 1:16 | 10.1186/1752-0509-1-16 | null | q-bio.NC physics.soc-ph | null | The organization of the connectivity between mammalian cortical areas has
become a major subject of study, because of its important role in scaffolding
the macroscopic aspects of animal behavior and intelligence. In this study we
present a computational reconstruction approach to the problem of network
organization, by considering the topological and spatial features of each area
in the primate cerebral cortex as subsidy for the reconstruction of the global
cortical network connectivity. Starting with all areas being disconnected,
pairs of areas with similar sets of features are linked together, in an attempt
to recover the original network structure. Inferring primate cortical
connectivity from the properties of the nodes, remarkably good reconstructions
of the global network organization could be obtained, with the topological
features allowing slightly superior accuracy to the spatial ones. Analogous
reconstruction attempts for the C. elegans neuronal network resulted in
substantially poorer recovery, indicating that cortical area interconnections
are relatively stronger related to the considered topological and spatial
properties than neuronal projections in the nematode. The close relationship
between area-based features and global connectivity may hint on developmental
rules and constraints for cortical networks. Particularly, differences between
the predictions from topological and spatial properties, together with the
poorer recovery resulting from spatial properties, indicate that the
organization of cortical networks is not entirely determined by spatial
constraints.
| [
{
"version": "v1",
"created": "Thu, 26 Apr 2007 20:13:58 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Costa",
"Luciano da F",
""
],
[
"Kaiser",
"Marcus",
""
],
[
"Hilgetag",
"Claus C",
""
]
] |
0704.3620 | Dale Li | Dale Li, Yanqun Dong, R. G. Ramos, J. D. Murray, K. MacLean, A. E.
Dementyev and S. E. Barrett | The Intrinsic Origin of Spin Echoes in Dipolar Solids Generated by
Strong Pi Pulses | 24 pages, 27 figures. Revised from helpful referee comments. Added
new Table IV, new paragraphs on pages 3 and 19 | null | 10.1103/PhysRevB.77.214306 | null | cond-mat.mes-hall quant-ph | null | In spectroscopy, it is conventional to treat pulses much stronger than the
linewidth as delta-functions. In NMR, this assumption leads to the prediction
that pi pulses do not refocus the dipolar coupling. However, NMR spin echo
measurements in dipolar solids defy these conventional expectations when more
than one pi pulse is used. Observed effects include a long tail in the CPMG
echo train for short delays between pi pulses, an even-odd asymmetry in the
echo amplitudes for long delays, an unusual fingerprint pattern for
intermediate delays, and a strong sensitivity to pi-pulse phase. Experiments
that set limits on possible extrinsic causes for the phenomena are reported. We
find that the action of the system's internal Hamiltonian during any real pulse
is sufficient to cause the effects. Exact numerical calculations, combined with
average Hamiltonian theory, identify novel terms that are sensitive to
parameters such as pulse phase, dipolar coupling, and system size.
Visualization of the entire density matrix shows a unique flow of quantum
coherence from non-observable to observable channels when applying repeated pi
pulses.
| [
{
"version": "v1",
"created": "Thu, 26 Apr 2007 19:40:50 GMT"
},
{
"version": "v2",
"created": "Fri, 24 Aug 2007 16:47:18 GMT"
},
{
"version": "v3",
"created": "Mon, 10 Mar 2008 17:13:52 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Li",
"Dale",
""
],
[
"Dong",
"Yanqun",
""
],
[
"Ramos",
"R. G.",
""
],
[
"Murray",
"J. D.",
""
],
[
"MacLean",
"K.",
""
],
[
"Dementyev",
"A. E.",
""
],
[
"Barrett",
"S. E.",
""
]
] |
0704.3621 | Paul E. Reimer | Paul E. Reimer | Exploring the Partonic Structure of Hadrons through the Drell-Yan
Process | 23 pages, 9 figures, to appear in J. Phys. G, resubmission corrects
typographical errors | J.Phys.G34:S107-S126,2007 | 10.1088/0954-3899/34/7/S06 | null | nucl-ex | null | The Drell-Yan process is a standard tool for probing the partonic structure
of hadrons. Since the process proceeds through a quark-antiquark annihilation,
Drell-Yan scattering possesses a unique ability to selectively probe sea
distributions. This review examines the application of Drell-Yan scattering to
elucidating the flavor asymmetry of the nucleon's sea and nuclear modifications
to the sea quark distributions in unpolarized scattering. Polarized beams and
targets add an exciting new dimension to Drell-Yan scattering. In particular,
the two initial-state hadrons give Drell-Yan sensitivity to chirally-odd
transversity distributions.
| [
{
"version": "v1",
"created": "Thu, 26 Apr 2007 20:33:14 GMT"
},
{
"version": "v2",
"created": "Tue, 1 May 2007 16:04:21 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Reimer",
"Paul E.",
""
]
] |
0704.3622 | Cynthia J. Olson Reichhardt | C. Reichhardt and C.J. Olson Reichhardt | Disordering Transitions and Peak Effect in Polydisperse Particle Systems | 8 pages, 8 postscript figures. Version to appear in PRE | Phys. Rev. E 77, 041401 (2008) | 10.1103/PhysRevE.77.041401 | null | cond-mat.soft cond-mat.supr-con | null | We show numerically that in a binary system of Yukawa particles, a dispersity
driven disordering transition occurs. In the presence of quenched disorder this
disordering transition coincides with a marked increase in the depinning
threshold, known as a peak effect. We find that the addition of poorly pinned
particles can increase the overall pinning in the sample by increasing the
amount of topological disorder present. If the quenched disorder is strong
enough to create a significant amount of topological disorder in the
monodisperse system, addition of a poorly pinned species generates further
disorder but does not produce a peak in the depinning force. Our results
indicate that for binary mixtures, optimal pinning occurs for topological
defect fraction densities of 0.2 to 0.25. For defect densities below this
range, the system retains orientational order. We determine the effect of the
pinning density, strength, and radius on the depinning peak and find that the
peak effect is more pronounced in weakly pinning systems.
| [
{
"version": "v1",
"created": "Thu, 26 Apr 2007 20:37:29 GMT"
},
{
"version": "v2",
"created": "Mon, 7 Apr 2008 20:30:04 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Reichhardt",
"C.",
""
],
[
"Reichhardt",
"C. J. Olson",
""
]
] |
0704.3623 | Masato Minamitsuji | Masato Minamitsuji | Casimir effect in a 6D warped flux compactification model | 18 pages, 6 figures, references and comments added, typos corrected | null | null | LMU-ASC 28/07 | gr-qc astro-ph hep-ph hep-th | null | We discuss Casimir effect of a massless, minimally coupled scalar field in a
6D warped flux compactification model and its implications for the hierarchy
and cosmological constant problems, which are longstanding puzzles in
phenomenology and cosmology. Due to the scale invariance of the background
theory, the 4D effective theory contains a volume modulus. To stabilize the
modulus, we consider one-loop corrections to the effective potential by the
Casimir effect. The one-loop effective potential for the volume modulus has a
form which is very similar to Coleman-Weinberg potential. We evaluate
coefficients appearing in the effective potential by employing zeta function
regularization and heat kernel analysis. The volume modulus is stabilized for
smaller degrees of warping, below a critical value, which depends on deficit
angle of the reference brane. After stabilizing the modulus, it is possible to
obtain observed values of the mass ratio between the fundamental energy scales
and a tiny effective cosmological constant (though its sign is negative). The
degree of warping should be tuned to be close to the critical value, not as
severely as the original fine-tuning.
| [
{
"version": "v1",
"created": "Thu, 26 Apr 2007 20:38:33 GMT"
},
{
"version": "v2",
"created": "Mon, 7 May 2007 08:33:44 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Minamitsuji",
"Masato",
""
]
] |
0704.3624 | Alexander D. Hernandez | Alexander D. Hernandez, Arturo Lopez, and Daniel Dominguez | Anisotropic ac dissipation at the surface of mesoscopic superconductors | 4 pages, 2 figures | Applied Surface Science 254, 69 (2007) | 10.1016/j.apsusc.2007.07.038 | null | cond-mat.supr-con cond-mat.mes-hall | null | In this work we study the ac dissipation of mesoscopic superconductors at
microwave frequencies using the time dependent Ginzburg-Landau equations. Our
numerical simulations show that the ac dissipation is strongly dependent on the
orientation of the ac magnetic field ($h_{ac}$) relative to the dc magnetic
field ($H_{dc}$). When $h_{ac}$ is parallel to $H_{dc}$ we observe that each
vortex penetration event produces a significant supression of the ac losses
because the imaginary part of the ac susceptibility as a function of $H_{dc}$
increases before the penetration of vortices, and then it decreases abruptly
after vortices have entered into the sample. In the second case, when $h_{ac}$
is perpendicular to $H_{dc}$, we observe that the jumps in dissipation occur at
the same values of $H_{dc}$ but are much smaller than in the parallel
configuration. The behavior of the dissipation in the perpendicular
configuration is similar to previous results obtained in recent microwave
experiments using mesoscopic litographed squares of Pb [J. Low Temp. Phys. 135,
119 (2004)].
| [
{
"version": "v1",
"created": "Thu, 26 Apr 2007 20:42:13 GMT"
}
] | 2008-06-06T00:00:00 | [
[
"Hernandez",
"Alexander D.",
""
],
[
"Lopez",
"Arturo",
""
],
[
"Dominguez",
"Daniel",
""
]
] |
0704.3625 | Kenji Fukushima | Kenji Fukushima | Initial fields and instability in the classical model of the heavy-ion
collision | 5 pages, 2 figures | Phys.Rev.C76:021902,2007; Erratum-ibid.C77:029901,2007 | 10.1103/PhysRevC.76.021902 10.1103/PhysRevC.77.029901 | RBRC-680 | hep-ph | null | Color Glass Condensate (CGC) provides a classical description of dense gluon
matter at high energies. Using the McLerran-Venugopalan (MV) model we calculate
the initial energy density \epsilon(\tau) in the early stage of the
relativistic nucleus-nucleus collision. Our analytical formula reproduces the
quantitative results from lattice discretized simulations and leads to an
estimate \epsilon(\tau=0.1fm)=40-50GeV/fm^3 in the Au-Au collision at RHIC
energy. We then formulate instability with respect to soft fluctuations that
violate boost invariance inherent to hard CGC backgrounds. We find unstable
modes arising as a result of ensemble average over the initial CGC fields.
| [
{
"version": "v1",
"created": "Thu, 26 Apr 2007 20:54:58 GMT"
},
{
"version": "v2",
"created": "Tue, 22 May 2007 18:47:41 GMT"
}
] | 2014-11-18T00:00:00 | [
[
"Fukushima",
"Kenji",
""
]
] |
0704.3626 | Ismail Turan | Mariana Frank, Ismail Turan (Concordia Univ.) and Lorric Ziegler
(Concordia Univ. and Univ. of Geneva) | The Casimir Force in Randall Sundrum Models | 16 pages, 2 figures, references added, text improved, accepted for
publication in PRD | Phys.Rev.D76:015008,2007 | 10.1103/PhysRevD.76.015008 | CUMQ/HEP 145 | hep-ph hep-th | null | We discuss and compare the effects of one extra dimension in the Randall
Sundrum models on the evaluation of the Casimir force between two parallel
plates. We impose the condition that the result reproduce the experimental
measurements within the known uncertainties in the force and the plate
separation, and get an upper bound kR < 20 if the curvature parameter k of
AdS_5 is equal to the Planck scale. Although the upper bound decreases as k
decreases, kR ~ 12, which is the required value for solving the hierarchy
problem, is consistent with the Casimir force measurements. For the case where
the 5th dimension is infinite, the correction to the Casimir force is very
small and negligible.
| [
{
"version": "v1",
"created": "Thu, 26 Apr 2007 20:55:50 GMT"
},
{
"version": "v2",
"created": "Tue, 12 Jun 2007 05:19:44 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Frank",
"Mariana",
"",
"Concordia Univ."
],
[
"Turan",
"Ismail",
"",
"Concordia Univ."
],
[
"Ziegler",
"Lorric",
"",
"Concordia Univ. and Univ. of Geneva"
]
] |
0704.3627 | Alastair Craw | Alastair Craw | The Special McKay correspondence as an equivalence of derived categories | 17 pages. Final version, to appear in Quart. J. Math | Quarterly Journal of Mathematics 62 (2011), 573-591 | null | null | math.AG math.RT | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We give a new moduli construction of the minimal resolution of the
singularity of type 1/r(1,a) by introducing the Special McKay quiver. To
demonstrate that our construction trumps that of the G-Hilbert scheme, we show
that the induced tautological line bundles freely generate the bounded derived
category of coherent sheaves on X by establishing a suitable derived
equivalence. This gives a moduli construction of the Special McKay
correspondence for abelian subgroups of GL(2).
| [
{
"version": "v1",
"created": "Thu, 26 Apr 2007 21:06:10 GMT"
},
{
"version": "v2",
"created": "Wed, 6 Aug 2008 16:52:56 GMT"
},
{
"version": "v3",
"created": "Mon, 25 Jan 2010 14:53:02 GMT"
},
{
"version": "v4",
"created": "Sat, 5 Jun 2010 16:26:23 GMT"
}
] | 2011-08-25T00:00:00 | [
[
"Craw",
"Alastair",
""
]
] |
0704.3628 | Andris Ambainis | Andris Ambainis | A nearly optimal discrete query quantum algorithm for evaluating NAND
formulas | 21 pages, 2 figures | null | null | null | quant-ph | null | We present an O(\sqrt{N}) discrete query quantum algorithm for evaluating
balanced binary NAND formulas and an O(N^{{1/2}+O(\frac{1}{\sqrt{\log N}})})
discrete query quantum algorithm for evaluating arbitrary binary NAND formulas.
| [
{
"version": "v1",
"created": "Thu, 26 Apr 2007 21:11:36 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Ambainis",
"Andris",
""
]
] |
0704.3629 | John H. Wise | John H. Wise, Tom Abel (KIPAC, Stanford) | Resolving the Formation of Protogalaxies. I. Virialization | 13 pages, 6 figures. Submitted to ApJ on 8 March 2007. Revised
manuscript. Comments welcome | Astrophys.J.665:899-910,2007 | 10.1086/520036 | null | astro-ph | null | (Abridged) Galaxies form in hierarchically assembling dark matter halos. With
cosmological three dimensional adaptive mesh refinement simulations, we explore
in detail the virialization of baryons in the concordance cosmology, including
optically thin primordial gas cooling. We focus on early protogalaxies with
virial temperatures of 10^4 K and their progenitors. Without cooling, virial
heating occurs in shocks close to the virial radius for material falling in
from voids. Material in dense filaments penetrates deeper to about half that
radius. With cooling the virial shock position shrinks and also the filaments
reach scales as small as a third the virial radius. The temperatures in
protogalaxies found in adiabatic simulations decrease by a factor of two from
the center and show flat entropy cores. In cooling halos the gas reaches virial
equilibrium with the dark matter potential through its turbulent velocities. We
observe turbulent Mach numbers ranging from one to three in the cooling cases.
This turbulence is driven by the large scale merging and interestingly remains
supersonic in the centers of these early galaxies even in the absence of any
feedback processes. The virial theorem is shown to approximately hold over 3
orders of magnitude in length scale with the turbulent pressure prevailing over
the thermal energy. The turbulent velocity distributions are Maxwellian and by
far dominate the small rotation velocities associated with the total angular
momentum of the galaxies. Decomposing the velocity field using the
Cauchy-Stokes theorem, we show that ample amounts of vorticity are present
around shocks even at the very centers of these objects.
| [
{
"version": "v1",
"created": "Thu, 26 Apr 2007 22:20:25 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"Wise",
"John H.",
"",
"KIPAC, Stanford"
],
[
"Abel",
"Tom",
"",
"KIPAC, Stanford"
]
] |
0704.3630 | Ming-Ho Siu | M. Stewart Siu | Adiabatic Rotation, Quantum Search and Preparation of Superposition
States | Expanded to 6 pages; Accepted by Phys. Rev. A | null | 10.1103/PhysRevA.75.062337 | null | quant-ph | null | We introduce the idea of using adiabatic rotation to generate superpositions
of a large class of quantum states. For quantum computing this is an
interesting alternative to the well-studied "straight line" adiabatic
evolution. In ways that complement recent results, we show how to efficiently
prepare three types of states: Kitaev's toric code state, the cluster state of
the measurement-based computation model and the history state used in the
adiabatic simulation of quantum circuit. We also show that the method, when
adapted for quantum search, provides quadratic speedup as other optimal methods
do with the advantages that the problem Hamiltonian is time-independent and
that the energy gap above the ground state is strictly nondecreasing with time.
Likewise the method can be used for optimization as an alternative to the usual
adiabatic algorithm.
| [
{
"version": "v1",
"created": "Thu, 26 Apr 2007 21:13:33 GMT"
},
{
"version": "v2",
"created": "Fri, 4 May 2007 01:12:15 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Siu",
"M. Stewart",
""
]
] |
0704.3631 | William Moore | W. Frank Moore | Cohomology of Fiber Products of Local Rings | 13 pages | Journal of Algebra 321 (2009) 758-773 | null | null | math.AC math.RA | null | Let $S$ and $T$ be local rings with common residue field $k$, let $R$ be the
fiber product $S \times_k T$, and let $M$ be an $S$-module. The Poincar\'e
series $P^R_M$ of $M$ has been expressed in terms of $P^S_M$, $P^S_k$ and
$P^T_k$ by Kostrikin and Shafarevich, and by Dress and Kr\"amer. Here, an
explicit minimal resolution, as well as theorems on the structure of
$\Ext_R(k,k)$ and $\Ext_R(M,k)$ are given that illuminate these equalities.
Structure theorems for the cohomology modules of fiber products of modules are
also given. As an application of these results, we compute the depth of
cohomology modules over a fiber product.
| [
{
"version": "v1",
"created": "Thu, 26 Apr 2007 21:32:46 GMT"
}
] | 2009-10-07T00:00:00 | [
[
"Moore",
"W. Frank",
""
]
] |
0704.3632 | Rolando Vald\'es Aguilar | R. Vald\'es Aguilar, A. B. Sushkov, C. L. Zhang, Y. J. Choi, S.-W.
Cheong and H. D. Drew | Colossal magnon-phonon coupling in multiferroic
Eu$_{0.75}$Y$_{0.25}$MnO$_3$ | 4 pages, 3 figures | Physical Review B 76 060404(R) (2007) | 10.1103/PhysRevB.76.060404 | null | cond-mat.mtrl-sci cond-mat.str-el | null | We report the spectra of magnetically induced electric dipole absorption in
Eu$_{0.75}$Y$_{0.25}$MnO$_3$ from temperature dependent far infrared
spectroscopy (10-250 cm$^{-1}$). These spectra, which occur only in the $e||a$
polarization, consist of two relatively narrow electromagnon features that
onset at $T_{FE}=30$ K and a broad absorption band that persists to
temperatures well above $T_N=47$ K. The observed excitations account for the
step up of the static dielectric constant in the ferroelectric phase. The
electromagnon at 80 cm$^{-1}$ is observed to be strongly coupled to the nearby
lowest optical phonon which transfers more than 1/2 of its spectral weight to
the magnon. We attribute the origin of the broad background absorption to the
two magnon emission decay process of the phonon.
| [
{
"version": "v1",
"created": "Thu, 26 Apr 2007 21:46:05 GMT"
},
{
"version": "v2",
"created": "Thu, 3 May 2007 21:57:27 GMT"
},
{
"version": "v3",
"created": "Wed, 20 Jun 2007 19:08:24 GMT"
},
{
"version": "v4",
"created": "Tue, 24 Jul 2007 15:36:51 GMT"
}
] | 2007-10-23T00:00:00 | [
[
"Aguilar",
"R. Valdés",
""
],
[
"Sushkov",
"A. B.",
""
],
[
"Zhang",
"C. L.",
""
],
[
"Choi",
"Y. J.",
""
],
[
"Cheong",
"S. -W.",
""
],
[
"Drew",
"H. D.",
""
]
] |
0704.3633 | Keir Lockridge | Mark Hovey and Keir H. Lockridge | Triangulations of projective modules | 15 pages | null | null | null | math.AC math.AT math.RT | null | We show that the category of projective modules over a graded commutative
ring admits a triangulation with respect to module suspension if and only if
the ring is a finite product of graded fields and exterior algebras on one
generator over a graded field (with a unit in the appropriate degree). We also
classify the ungraded commutative rings for which the category of projective
modules admits a triangulation with respect to the identity suspension.
Applications to two analogues of the generating hypothesis in algebraic
topology are given, and we translate our results into the setting of modules
over a symmetric ring spectrum or S-algebra.
| [
{
"version": "v1",
"created": "Thu, 26 Apr 2007 22:01:47 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Hovey",
"Mark",
""
],
[
"Lockridge",
"Keir H.",
""
]
] |
0704.3634 | Paul Lasky | Paul Lasky, Anthony Lun | Gravitational collapse of spherically symmetric plasmas in
Einstein-Maxwell spacetimes | Accepted for publication in Phys. Rev. D | Phys.Rev.D75:104010,2007 | 10.1103/PhysRevD.75.104010 | null | gr-qc | null | We utilize a recent formulation of a spherically symmetric spacetime endowed
with a general decomposition of the energy momentum tensor [Phys. Rev. D, 75,
024031 (2007)] to derive equations governing spherically symmetric
distributions of electromagnetic matter. We show the system reduces to the
Reissner-Nordstrom spacetime in general, spherically symmetric coordinates in
the vacuum limit. Furthermore, we show reduction to the charged Vaidya
spacetime in non-null coordinates when certain equations of states are chosen.
A model of gravitational collapse is discussed whereby a charged fluid resides
within a boundary of finite radial extent on the initial hypersurface, and is
allowed to radiate charged particles. Our formalism allows for the discussion
of all regions in this model without the need for complicated matching schemes
at the interfaces between successive regions. As further examples we consider
the collapse of a thin shell of charged matter onto a Reissner-Nordstrom black
hole. Finally, we reduce the entire system of equations to the static case such
that we have the equations for hydrostatic equilibrium of a charged fluid.
| [
{
"version": "v1",
"created": "Thu, 26 Apr 2007 22:15:13 GMT"
},
{
"version": "v2",
"created": "Mon, 7 May 2007 01:02:23 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Lasky",
"Paul",
""
],
[
"Lun",
"Anthony",
""
]
] |
0704.3635 | Fulufhelo Vincent Nelwamondo | Fulufhelo Vincent Nelwamondo and Tshilidzi Marwala | Rough Sets Computations to Impute Missing Data | 19 pages | null | null | null | cs.CV cs.IR | null | Many techniques for handling missing data have been proposed in the
literature. Most of these techniques are overly complex. This paper explores an
imputation technique based on rough set computations. In this paper,
characteristic relations are introduced to describe incompletely specified
decision tables.It is shown that the basic rough set idea of lower and upper
approximations for incompletely specified decision tables may be defined in a
variety of different ways. Empirical results obtained using real data are given
and they provide a valuable and promising insight to the problem of missing
data. Missing data were predicted with an accuracy of up to 99%.
| [
{
"version": "v1",
"created": "Thu, 26 Apr 2007 22:22:45 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Nelwamondo",
"Fulufhelo Vincent",
""
],
[
"Marwala",
"Tshilidzi",
""
]
] |
0704.3636 | Robert Buckingham | Jinho Baik, Robert Buckingham, and Jeffery DiFranco | Asymptotics of Tracy-Widom distributions and the total integral of a
Painlev\'e II function | 29 pages, 1 figure | null | 10.1007/s00220-008-0433-5 | null | math.FA math-ph math.MP math.PR nlin.SI | null | The Tracy-Widom distribution functions involve integrals of a Painlev\'e II
function starting from positive infinity. In this paper, we express the
Tracy-Widom distribution functions in terms of integrals starting from minus
infinity. There are two consequences of these new representations. The first is
the evaluation of the total integral of the Hastings-McLeod solution of the
Painlev\'e II equation. The second is the evaluation of the constant term of
the asymptotic expansions of the Tracy-Widom distribution functions as the
distribution parameter approaches minus infinity. For the GUE Tracy-Widom
distribution function, this gives an alternative proof of the recent work of
Deift, Its, and Krasovsky. The constant terms for the GOE and GSE Tracy-Widom
distribution functions are new.
| [
{
"version": "v1",
"created": "Thu, 26 Apr 2007 22:35:55 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Baik",
"Jinho",
""
],
[
"Buckingham",
"Robert",
""
],
[
"DiFranco",
"Jeffery",
""
]
] |
0704.3637 | Han Uitenbroek | Han Uitenbroek, Alexandra Tritschler, and Thomas Rimmele | The discrepancy in G-band contrast: Where is the quiet Sun? | 16 pages, 8 figures | null | 10.1086/521217 | null | astro-ph | null | We compare the rms contrast in observed speckle reconstructed G-band images
with synthetic filtergrams computed from two magneto-hydrodynamic simulation
snapshots. The observations consist of 103 bursts of 80 frames each taken at
the Dunn Solar Telescope (DST), sampled at twice the diffraction limit of the
telescope. The speckle reconstructions account for the performance of the
Adaptive Optics (AO) system at the DST to supply reliable photometry. We find a
considerable discrepancy in the observed rms contrast of 14.1% for the best
reconstructed images, and the synthetic rms contrast of 21.5% in a simulation
snapshot thought to be representative of the quiet Sun. The areas of features
in the synthetic filtergrams that have positive or negative contrast beyond the
minimum and maximum values in the reconstructed images have spatial scales that
should be resolved. This leads us to conclude that there are fundamental
differences in the rms G-band contrast between observed and computed
filtergrams. On the basis of the substantially reduced granular contrast of
16.3% in the synthetic plage filtergram we speculate that the quiet-Sun may
contain more weak magnetic field than previously thought.
| [
{
"version": "v1",
"created": "Thu, 26 Apr 2007 22:47:14 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Uitenbroek",
"Han",
""
],
[
"Tritschler",
"Alexandra",
""
],
[
"Rimmele",
"Thomas",
""
]
] |
0704.3638 | Radu Roiban | R. Roiban, A. Tirziu and A. A. Tseytlin | Two-loop world-sheet corrections in AdS_5 x S^5 superstring | 48 pages, 1 Figure. v3: several mistakes corrected, the finite result
for the 2-loop coefficient is found to agree with the numerical value found
by Benna et al in hep-th/0611135 | JHEP 0707:056,2007 | 10.1088/1126-6708/2007/07/056 | Imperial-TP-AT-2007-1 | hep-th | null | We initiate the computation of the 2-loop quantum AdS_5 x S^5 string
corrections on the example of a certain string configuration in S^5 related by
an analytic continuation to a folded rotating string in AdS_5 in the ``long
string'' limit. The 2-loop term in the energy of the latter should represent
the subleading strong-coupling correction to the cusp anomalous dimension and
thus provide a further check of recent conjectures about the exact structure of
the Bethe ansatz underlying the AdS/CFT duality. We use the conformal gauge and
several choices of the \kappa-symmetry gauge. While we are unable to verify the
cancellation of 2d UV divergences we compute the bosonic contribution to the
effective action and also determine the non-trivial finite part of the
fermionic contribution. Both the bosonic and the fermionic contributions to the
string energy happen to be proportional to the Catalan's constant. The
resulting value for 2-loop superstring prediction for the subleading
coefficient a_2 in the scaling function matches the numerical value found in
hep-th/0611135 from the BES equation.
| [
{
"version": "v1",
"created": "Fri, 27 Apr 2007 19:57:03 GMT"
},
{
"version": "v2",
"created": "Sun, 29 Apr 2007 19:40:45 GMT"
},
{
"version": "v3",
"created": "Wed, 29 Aug 2007 19:58:36 GMT"
},
{
"version": "v4",
"created": "Thu, 30 Aug 2007 17:28:02 GMT"
}
] | 2009-09-17T00:00:00 | [
[
"Roiban",
"R.",
""
],
[
"Tirziu",
"A.",
""
],
[
"Tseytlin",
"A. A.",
""
]
] |
0704.3639 | Filipe Tostevin | Filipe Tostevin, Pieter Rein ten Wolde, Martin Howard | Fundamental Limits to Position Determination by Concentration Gradients | 24 pages, 2 figures | PLoS Computational Biology 3 e78 (2007) | 10.1371/journal.pcbi.0030078 | null | q-bio.SC cond-mat.stat-mech | null | Position determination in biological systems is often achieved through
protein concentration gradients. Measuring the local concentration of such a
protein with a spatially-varying distribution allows the measurement of
position within the system. In order for these systems to work effectively,
position determination must be robust to noise. Here, we calculate fundamental
limits to the precision of position determination by concentration gradients
due to unavoidable biochemical noise perturbing the gradients. We focus on
gradient proteins with first order reaction kinetics. Systems of this type have
been experimentally characterised in both developmental and cell biology
settings. For a single gradient we show that, through time-averaging, great
precision can potentially be achieved even with very low protein copy numbers.
As a second example, we investigate the ability of a system with oppositely
directed gradients to find its centre. With this mechanism, positional
precision close to the centre improves more slowly with increasing averaging
time, and so longer averaging times or higher copy numbers are required for
high precision. For both single and double gradients, we demonstrate the
existence of optimal length scales for the gradients, where precision is
maximized, as well as analyzing how precision depends on the size of the
concentration measuring apparatus. Our results provide fundamental constraints
on the positional precision supplied by concentration gradients in various
contexts, including both in developmental biology and also within a single
cell.
| [
{
"version": "v1",
"created": "Thu, 26 Apr 2007 23:03:03 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Tostevin",
"Filipe",
""
],
[
"Wolde",
"Pieter Rein ten",
""
],
[
"Howard",
"Martin",
""
]
] |
0704.3640 | Dennis Wylie | Dennis Cates Wylie | Linked by Loops: Network Structure and Switch Integration in Complex
Dynamical Systems | 21 pages, 5 figures. Paper simplified and shortened. Quantities
presented in table 1 are different, though related, to quantities previously
presented in table 1 | null | null | null | q-bio.QM cond-mat.dis-nn math.DS nlin.CD | null | Simple nonlinear dynamical systems with multiple stable stationary states are
often taken as models for switchlike biological systems. This paper considers
the interaction of multiple such simple multistable systems when they are
embedded together into a larger dynamical "supersystem." Attention is focused
on the network structure of the resulting set of coupled differential
equations, and the consequences of this structure on the propensity of the
embedded switches to act independently versus cooperatively. Specifically, it
is argued that both larger average and larger variance of the node degree
distribution lead to increased switch independence. Given the frequency of
empirical observations of high variance degree distributions (e.g., power-law)
in biological networks, it is suggested that the results presented here may aid
in identifying switch-integrating subnetworks as comparatively homogenous,
low-degree, substructures. Potential applications to ecological problems such
as the relationship of stability and complexity are also briefly discussed.
| [
{
"version": "v1",
"created": "Thu, 26 Apr 2007 23:24:28 GMT"
},
{
"version": "v2",
"created": "Fri, 13 Jul 2007 01:51:03 GMT"
},
{
"version": "v3",
"created": "Tue, 22 Jan 2008 18:57:14 GMT"
},
{
"version": "v4",
"created": "Thu, 10 Apr 2008 20:34:39 GMT"
}
] | 2008-04-10T00:00:00 | [
[
"Wylie",
"Dennis Cates",
""
]
] |
0704.3641 | Charis Quay | C. H. L. Quay, John Cumings, Sara Gamble, R. de Picciotto, H. Kataura,
D. Goldhaber-Gordon | Kondo Physics in Nanotubes: Magnetic-field dependence and
singlet-triplet Kondo | 10 pp., 5 fig. cond-mat/0606258 was split into two papers to clarify
their separate stories. cond-mat/0606258v2 treats the effect of C60
intercalation on transport in nanotubes. 0704.3641 is on Kondo physics in a
nanotube in B-field. We now note: the splitting of Kondo resonances with
B-field is sub-linear at low field, in qualitative agreement with theories | null | null | null | cond-mat.mes-hall | null | In a single-walled carbon nanotube, we observe the spin-1/2 Kondo effect. The
energy of spin-resolved Kondo peaks is proportional to magnetic field at high
fields, contrary to recent reports. At lower fields, the energy falls below
this linear dependence, in qualitative agreement with theoretical expectations.
For even electron occupancy, we observe a spin-1 Kondo effect due to the
degeneracy of the triplet ground states. Tuning gate voltage within the same
Coulomb diamond drives a transition to a singlet ground state. We also
independently tune the energy difference between singlet and triplet states
with a magnetic field. The Zeeman splitting thus measured confirms the value of
the g-factor measured from the spin-1/2 Kondo feature.
| [
{
"version": "v1",
"created": "Fri, 27 Apr 2007 03:30:43 GMT"
},
{
"version": "v2",
"created": "Sun, 29 Apr 2007 04:12:03 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Quay",
"C. H. L.",
""
],
[
"Cumings",
"John",
""
],
[
"Gamble",
"Sara",
""
],
[
"de Picciotto",
"R.",
""
],
[
"Kataura",
"H.",
""
],
[
"Goldhaber-Gordon",
"D.",
""
]
] |
0704.3642 | Benjamin Schmidt | Benjamin Schmidt and Juan Souto | A characterization of round spheres in terms of blocking light | Replaced a theorem from an earlier version with a reference and added
a new theorem | null | null | null | math.GT math.DG | null | A closed Riemannian manifold is said to have cross blocking if whenever
distinct points p and q are at distance less than the diameter, all light rays
from p can be shaded away from q with at most two point shades. Similarly, a
closed Riemannian manifold is said to have sphere blocking if for each point p,
all the light rays from p are shaded away from p by a single point shade. We
prove that Riemannian manifolds with cross and sphere blocking are isometric to
round spheres.
| [
{
"version": "v1",
"created": "Fri, 27 Apr 2007 00:41:49 GMT"
},
{
"version": "v2",
"created": "Fri, 14 Mar 2008 02:56:48 GMT"
}
] | 2008-03-14T00:00:00 | [
[
"Schmidt",
"Benjamin",
""
],
[
"Souto",
"Juan",
""
]
] |
0704.3643 | Allison Woodruff | Allison Woodruff, Sally Augustin, and Brooke Foucault | Sabbath Day Home Automation: "It's Like Mixing Technology and Religion" | null | null | null | null | cs.HC | null | We present a qualitative study of 20 American Orthodox Jewish families' use
of home automation for religious purposes. These lead users offer insight into
real-life, long-term experience with home automation technologies. We discuss
how automation was seen by participants to contribute to spiritual experience
and how participants oriented to the use of automation as a religious custom.
We also discuss the relationship of home automation to family life. We draw
design implications for the broader population, including surrender of control
as a design resource, home technologies that support long-term goals and
lifestyle choices, and respite from technology.
| [
{
"version": "v1",
"created": "Fri, 27 Apr 2007 00:42:22 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Woodruff",
"Allison",
""
],
[
"Augustin",
"Sally",
""
],
[
"Foucault",
"Brooke",
""
]
] |
0704.3644 | Chris Ng | Chris T. K. Ng, Nihar Jindal, Andrea J. Goldsmith, Urbashi Mitra | Capacity Gain from Two-Transmitter and Two-Receiver Cooperation | Accepted for publication in IEEE Transactions on Information Theory | null | 10.1109/TIT.2007.904987 | null | cs.IT math.IT | null | Capacity improvement from transmitter and receiver cooperation is
investigated in a two-transmitter, two-receiver network with phase fading and
full channel state information available at all terminals. The transmitters
cooperate by first exchanging messages over an orthogonal transmitter
cooperation channel, then encoding jointly with dirty paper coding. The
receivers cooperate by using Wyner-Ziv compress-and-forward over an analogous
orthogonal receiver cooperation channel. To account for the cost of
cooperation, the allocation of network power and bandwidth among the data and
cooperation channels is studied. It is shown that transmitter cooperation
outperforms receiver cooperation and improves capacity over non-cooperative
transmission under most operating conditions when the cooperation channel is
strong. However, a weak cooperation channel limits the transmitter cooperation
rate; in this case receiver cooperation is more advantageous.
Transmitter-and-receiver cooperation offers sizable additional capacity gain
over transmitter-only cooperation at low SNR, whereas at high SNR transmitter
cooperation alone captures most of the cooperative capacity improvement.
| [
{
"version": "v1",
"created": "Fri, 27 Apr 2007 00:52:11 GMT"
}
] | 2016-11-17T00:00:00 | [
[
"Ng",
"Chris T. K.",
""
],
[
"Jindal",
"Nihar",
""
],
[
"Goldsmith",
"Andrea J.",
""
],
[
"Mitra",
"Urbashi",
""
]
] |
0704.3645 | N. Christopher Phillips | Ja A Jeong, Hiroyuki Osaka, N. Christopher Phillips, Tamotsu Teruya | Cancellation for inclusions of C*-algebras of finite depth | 22 pages; AMSLaTeX | null | null | null | math.OA | null | Let B be a unital C*-algebra, let A be a unital subalgebra, and let E be a
conditional expectation from B to A with index-finite type and a quasi-basis of
n elements. Then the topological stable rank satisfies \tsr (B) \leq \tsr (A) +
n - 1. As an application, we show that if a unital inclusion A \subset B of
C*-algebras has index-finite type and finite depth, and A is simple with stable
rank one and Property (SP), then B has cancellation. In particular, if A is a
simple unital C*-algebra with stable rank one and Property (SP), and a finite
group G acts on A, then the crossed product has cancellation. Separately, if
the group is the integers, we obtain cancellation under the additional
hypotheses that the group action is outer and is trivial on K_0 (A).
| [
{
"version": "v1",
"created": "Fri, 27 Apr 2007 01:03:34 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Jeong",
"Ja A",
""
],
[
"Osaka",
"Hiroyuki",
""
],
[
"Phillips",
"N. Christopher",
""
],
[
"Teruya",
"Tamotsu",
""
]
] |
0704.3646 | Joseph Y. Halpern | Ittai Abraham, Danny Dolev, and Joseph Y. Halpern | Lower Bounds on Implementing Robust and Resilient Mediators | null | null | null | null | cs.GT cs.CR cs.DC | null | We consider games that have (k,t)-robust equilibria when played with a
mediator, where an equilibrium is (k,t)-robust if it tolerates deviations by
coalitions of size up to k and deviations by up to $t$ players with unknown
utilities. We prove lower bounds that match upper bounds on the ability to
implement such mediators using cheap talk (that is, just allowing communication
among the players). The bounds depend on (a) the relationship between k, t, and
n, the total number of players in the system; (b) whether players know the
exact utilities of other players; (c) whether there are broadcast channels or
just point-to-point channels; (d) whether cryptography is available; and (e)
whether the game has a $k+t)-punishment strategy; that is, a strategy that, if
used by all but at most $k+t$ players, guarantees that every player gets a
worse outcome than they do with the equilibrium strategy.
| [
{
"version": "v1",
"created": "Fri, 27 Apr 2007 01:32:15 GMT"
},
{
"version": "v2",
"created": "Thu, 6 Dec 2007 22:17:40 GMT"
}
] | 2007-12-07T00:00:00 | [
[
"Abraham",
"Ittai",
""
],
[
"Dolev",
"Danny",
""
],
[
"Halpern",
"Joseph Y.",
""
]
] |
0704.3647 | Catherine Marshall | Catherine C. Marshall, Frank McCown, and Michael L. Nelson | Evaluating Personal Archiving Strategies for Internet-based Information | 6 pages, 2 tables, to be published in the Proceedings of IS&T
Archiving 2007, May 21-24 2007, Arlington, Virginia, USA | null | null | null | cs.DL cs.CY cs.HC | null | Internet-based personal digital belongings present different vulnerabilities
than locally stored materials. We use responses to a survey of people who have
recovered lost websites, in combination with supplementary interviews, to paint
a fuller picture of current curatorial strategies and practices. We examine the
types of personal, topical, and commercial websites that respondents have lost
and the reasons they have lost this potentially valuable material. We further
explore what they have tried to recover and how the loss influences their
subsequent practices. We found that curation of personal digital materials in
online stores bears some striking similarities to the curation of similar
materials stored locally in that study participants continue to archive
personal assets by relying on a combination of benign neglect, sporadic
backups, and unsystematic file replication. However, we have also identified
issues specific to Internet-based material: how risk is spread by distributing
the files among multiple servers and services; the circular reasoning
participants use when they discuss the safety of their digital assets; and the
types of online material that are particularly vulnerable to loss. The study
reveals ways in which expectations of permanence and notification are violated
and situations in which benign neglect has far greater consequences for the
long-term fate of important digital assets.
| [
{
"version": "v1",
"created": "Fri, 27 Apr 2007 01:38:55 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Marshall",
"Catherine C.",
""
],
[
"McCown",
"Frank",
""
],
[
"Nelson",
"Michael L.",
""
]
] |
0704.3648 | Muhammad Sharif | M. Sharif | Perturbed Self-Similar Massless Scalar Field in Spherically Symmetric
Spaceimes | 15 pages, accepted for publication Int. J. Mod. Phys. A | Int.J.Mod.Phys.A22:4695-4708,2007 | 10.1142/S0217751X07037214 | null | gr-qc | null | In this paper, we investigate the linear perturbations of the spherically
symmetric spacetimes with kinematic self-similarity of the second kind. The
massless scalar field equations are solved which yield the background and an
exact solutions for the perturbed equations. We discuss the boundary conditions
of the resulting perturbed solutions. The possible perturbation modes turn out
to be stable as well as unstable. The analysis leads to the conclusion that
there does not exist any critical solution.
| [
{
"version": "v1",
"created": "Fri, 27 Apr 2007 02:11:59 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Sharif",
"M.",
""
]
] |
0704.3649 | Ivan Fernandez-Val | Victor Chernozhukov (MIT), Ivan Fernandez-Val (Boston University),
Alfred Galichon (Ecole Polytechnique) | Quantile and Probability Curves Without Crossing | 29 pages, 4 figures | Econometrica (2010) 78 (3): 1093-1125 | 10.3982/ECTA7880 | null | stat.ME econ.EM math.ST stat.TH | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | This paper proposes a method to address the longstanding problem of lack of
monotonicity in estimation of conditional and structural quantile functions,
also known as the quantile crossing problem. The method consists in sorting or
monotone rearranging the original estimated non-monotone curve into a monotone
rearranged curve. We show that the rearranged curve is closer to the true
quantile curve in finite samples than the original curve, establish a
functional delta method for rearrangement-related operators, and derive
functional limit theory for the entire rearranged curve and its functionals. We
also establish validity of the bootstrap for estimating the limit law of the
the entire rearranged curve and its functionals. Our limit results are generic
in that they apply to every estimator of a monotone econometric function,
provided that the estimator satisfies a functional central limit theorem and
the function satisfies some smoothness conditions. Consequently, our results
apply to estimation of other econometric functions with monotonicity
restrictions, such as demand, production, distribution, and structural
distribution functions. We illustrate the results with an application to
estimation of structural quantile functions using data on Vietnam veteran
status and earnings.
| [
{
"version": "v1",
"created": "Fri, 27 Apr 2007 18:58:35 GMT"
},
{
"version": "v2",
"created": "Sat, 25 Jul 2009 19:52:22 GMT"
},
{
"version": "v3",
"created": "Tue, 15 Jul 2014 01:40:35 GMT"
}
] | 2017-10-04T00:00:00 | [
[
"Chernozhukov",
"Victor",
"",
"MIT"
],
[
"Fernandez-Val",
"Ivan",
"",
"Boston University"
],
[
"Galichon",
"Alfred",
"",
"Ecole Polytechnique"
]
] |
0704.3650 | Jan Felipe van Diejen | J.F. van Diejen, A.C. de la Maza, and S. Ryom-Hansen | Bernstein-Szego Polynomials Associated with Root Systems | LaTeX, 12 pages | Bull. London Math. Soc. 39 (2007), 837-847 | 10.1112/blms/bdm073 | null | math.CO | null | We introduce multivariate generalizations of the Bernstein-Szego polynomials,
which are associated to the root systems of the complex simple Lie algebras.
The multivariate polynomials in question generalize Macdonald's Hall-Littlewood
polynomials associated with root systems. For the root system of type A1
(corresponding to the Lie algebra SL (2;C)) the classic Bernstein-Szego
polynomials are recovered.
| [
{
"version": "v1",
"created": "Fri, 27 Apr 2007 19:52:46 GMT"
}
] | 2010-09-27T00:00:00 | [
[
"van Diejen",
"J. F.",
""
],
[
"de la Maza",
"A. C.",
""
],
[
"Ryom-Hansen",
"S.",
""
]
] |
0704.3651 | N. Christopher Phillips | Hiroyuki Osaka, N. Christopher Phillips | Crossed products by finite group actions with the Rokhlin property | 22 pages; AMSLaTeX. Changes for version 3: One theorem (on ideals in
crossed products by the Rokhlin property) removed; it will appear in a
different paper. Minor improvements. Changes for version 2: Substantial
expansion | null | null | null | math.OA | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We prove that a number of classes of separable unital C*-algebras are closed
under crossed products by finite group actions with the Rokhlin property,
including:
(1) AI algebras, AT algebras, and related classes characterized by direct
limit decompositions using semiprojective building blocks.
(2) Simple unital AH algebras with slow dimension growth and real rank zero.
(3) C*-algebras with real rank zero or stable rank one.
(4) C*-algebras whose quotients all satisfy the Universal Coefficient
Theorem.
Along the way, we give a systematic treatment of the derivation of direct
limit decompositions from local approximation conditions by homomorphic images
which are not necessarily injective.
| [
{
"version": "v1",
"created": "Fri, 27 Apr 2007 19:44:49 GMT"
},
{
"version": "v2",
"created": "Thu, 27 Nov 2008 21:01:15 GMT"
},
{
"version": "v3",
"created": "Fri, 6 Feb 2009 18:06:30 GMT"
}
] | 2009-02-06T00:00:00 | [
[
"Osaka",
"Hiroyuki",
""
],
[
"Phillips",
"N. Christopher",
""
]
] |
0704.3652 | Bingsong Zou | Jia-Jun Wu, Qiang Zhao, B.S.Zou | Possibility of measuring a0(980)-f0(980) mixing from J/psi -> phi a0 | accepted version by PRD, slightly modified according to referee's
suggestions | Phys.Rev.D75:114012,2007 | 10.1103/PhysRevD.75.114012 | null | hep-ph | null | The a0(980)-f0(980) mixing intensity has been predicted to be in the range of
0.01 to 0.1 by various theoretical models, but lacking firm experimental
observation. We examine the possibility of extracting the a0(980)-f0(980)
mixing from J/psi -> phi f0 -> phi a0 reaction at upgraded Beijing Electron
Positron Collider with BESIII detector. While the branching ratio of this
process through the a0(980)-f0(980) mixing is expected to be about $O(10^{-6})$
similar to the estimated total amount from two background reactions J/psi ->
gamma* -> phi a0 and J/psi -> K* K + c.c. -> phi a0, the peak width from the
a0(980)-f0(980) mixing is about 8 MeV, much smaller than that from other
mechanisms. With $10^9$ $J/\psi$ events at BESIII, the a0(980)-f0(980) mixing
intensity is expected to be unambiguously and precisely measured.
| [
{
"version": "v1",
"created": "Fri, 27 Apr 2007 02:25:25 GMT"
},
{
"version": "v2",
"created": "Fri, 4 May 2007 01:49:18 GMT"
},
{
"version": "v3",
"created": "Sat, 26 May 2007 03:19:27 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Wu",
"Jia-Jun",
""
],
[
"Zhao",
"Qiang",
""
],
[
"Zou",
"B. S.",
""
]
] |
0704.3653 | Catherine Marshall | Catherine C. Marshall, Sara Bly, and Francoise Brun-Cottan | The Long Term Fate of Our Digital Belongings: Toward a Service Model for
Personal Archives | 6 pages, published in the Proceedings of IS&T Archiving 2006,
(Ottawa, Canada, May 23-26, 2006), Society for Imaging Science and
Technology, Springfield, VA, 2006, pp. 25-30 | null | null | null | cs.DL cs.CY cs.HC | null | We conducted a preliminary field study to understand the current state of
personal digital archiving in practice. Our aim is to design a service for the
long-term storage, preservation, and access of digital belongings by examining
how personal archiving needs intersect with existing and emerging archiving
technologies, best practices, and policies. Our findings not only confirmed
that experienced home computer users are creating, receiving, and finding an
increasing number of digital belongings, but also that they have already lost
irreplaceable digital artifacts such as photos, creative efforts, and records.
Although participants reported strategies such as backup and file replication
for digital safekeeping, they were seldom able to implement them consistently.
Four central archiving themes emerged from the data: (1) people find it
difficult to evaluate the worth of accumulated materials; (2) personal storage
is highly distributed both on- and offline; (3) people are experiencing
magnified curatorial problems associated with managing files in the aggregate,
creating appropriate metadata, and migrating materials to maintainable formats;
and (4) facilities for long-term access are not supported by the current
desktop metaphor. Four environmental factors further complicate archiving in
consumer settings: the pervasive influence of malware; consumer reliance on ad
hoc IT providers; an accretion of minor system and registry inconsistencies;
and strong consumer beliefs about the incorruptibility of digital forms, the
reliability of digital technologies, and the social vulnerability of networked
storage.
| [
{
"version": "v1",
"created": "Fri, 27 Apr 2007 02:35:57 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Marshall",
"Catherine C.",
""
],
[
"Bly",
"Sara",
""
],
[
"Brun-Cottan",
"Francoise",
""
]
] |
0704.3654 | Bunyo Hatsukade | Bunyo Hatsukade, Kotaro Kohno, Akira Endo, Tomoka Tosaki, Kouji Ohta,
Seiichi Sakamoto, Nobuyuki Kawai, Juan R. Cortes, Kouichiro Nakanishi,
Takeshi Okuda, Kazuyuki Muraoka, Takeshi Sakai, Paul M. Vreeswijk, Hajime
Ezawa, Nobuyuki Yamaguchi, Kazuhisa Kamegai, Ryohei Kawabe | A Search for CO(J=3-2) Emission from the Host Galaxy of GRB 980425 with
the Atacama Submillimeter Telescope Experiment | 7 pages, 4 figures | Publ.Astron.Soc.Jap.59:67-72,2007 | 10.1093/pasj/59.1.67 | null | astro-ph | null | We report on a deep search for CO(J=3-2) line emission from the host galaxy
of GRB 980425 with the Atacama Submillimeter Telescope Experiment (ASTE). We
observed five points of the galaxy covering the entire region. After combining
all of the spectra, we obtained a global spectrum with the rms noise level of
3.3 mK in T_mb scale at a velocity resolution of 10 km s^-1. No significant
emission was detected, though we find a marginal emission feature in the
velocity range corresponding to the redshift of the galaxy. We derive 3 sigma
upper limits on the global properties: the velocity-integrated CO(3-2)
intensity of I_CO(3-2) < 0.26 K km s^-1 by adopting a velocity width of 67 km
s^-1; the H_2 column density of N(H_2) < 3 x 10^20 cm^-2; the molecular gas
mass of M(H_2) < 3 x 10^8 M_sun, by assuming a CO line luminosity to H_2
molecular gas mass conversion factor of X_CO = 5.0 x 10^20 cm^-2 (K km
s^-1)^-1; and the star formation rate of SFR < 0.1 M_sun yr^-1, based on the
Schmidt law. The SFR is consistent with the previous results of H_alpha and
mid-IR observations, thereby suggesting that there is no significant obscured
star formation in the host galaxy of GRB 980425. This result implies that there
is a variety of GRB hosts with regard to the presence of obscured star
formation.
| [
{
"version": "v1",
"created": "Fri, 27 Apr 2007 03:17:25 GMT"
}
] | 2015-05-13T00:00:00 | [
[
"Hatsukade",
"Bunyo",
""
],
[
"Kohno",
"Kotaro",
""
],
[
"Endo",
"Akira",
""
],
[
"Tosaki",
"Tomoka",
""
],
[
"Ohta",
"Kouji",
""
],
[
"Sakamoto",
"Seiichi",
""
],
[
"Kawai",
"Nobuyuki",
""
],
[
"Cortes",
"Juan R.",
""
],
[
"Nakanishi",
"Kouichiro",
""
],
[
"Okuda",
"Takeshi",
""
],
[
"Muraoka",
"Kazuyuki",
""
],
[
"Sakai",
"Takeshi",
""
],
[
"Vreeswijk",
"Paul M.",
""
],
[
"Ezawa",
"Hajime",
""
],
[
"Yamaguchi",
"Nobuyuki",
""
],
[
"Kamegai",
"Kazuhisa",
""
],
[
"Kawabe",
"Ryohei",
""
]
] |
0704.3655 | Wang Qing | Ran Lu, Qing Wang | Equivalence of different descriptions for $\eta$ Particle in Simplest
Little Higgs Model | 7 pages | Chin.Phys.Lett.24:3371-3373,2007 | 10.1088/0256-307X/24/12/023 | null | hep-ph | null | In SU(3) simplest little Higgs model, a characteristic particle is the light
pseudoscalar boson eta, it leads interesting signals in the LHC/ILC and is
studied in literature with different parameterizations. In this work, we show
that these different descriptions for eta particle are equivalent up to some
SU(3) rotations as long as we suitably redefine the pseudo Goldstone boson
fields. We evaluate the necessary SU(3) rotations and built up explicit
expressions for redefined fields.
| [
{
"version": "v1",
"created": "Fri, 27 Apr 2007 04:21:54 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Lu",
"Ran",
""
],
[
"Wang",
"Qing",
""
]
] |
0704.3656 | Anders Biltmo | A. Biltmo and P. Henelius | Phase diagram of the dilute magnet LiHo_xY_{1-x}F_4 | 5 pages, 4 figures | Phys. Rev. B 76, 054423 (2007) | 10.1103/PhysRevB.76.054423 | null | cond-mat.stat-mech cond-mat.dis-nn | null | We study the effective long-range Ising dipole model with a local exchange
interaction appropriate for the dilute magnetic compound LiHo_{x}Y_{1-x}F_4.
Our calculations yield a value of 0.12 K for the nearest neighbor exchange
interaction. Using a Monte Carlo method we calculate the phase boundary T_c(x)
between the ferromagnetic and paramagnetic phases. We demonstrate that the
experimentally observed linear decrease in T_c with dilution is not the simple
mean-field result, but a combination of the effects of fluctuations, the
exchange interaction and the hyperfine coupling. Furthermore, we find a
critical dilution x_c=0.21(2), below which there is no ordering. In agreement
with recent Monte Carlo simulations on a similar model, we find no evidence of
the experimentally observed freezing of the glassy state in our calculation. We
apply the theory of Stephen and Aharony to LiHo_{x}Y_{1-x}F_4 and find that the
theory does predict a finite-temperature freezing of the spin glass. Reasons
for the discrepancies are discussed.
| [
{
"version": "v1",
"created": "Fri, 27 Apr 2007 15:25:37 GMT"
},
{
"version": "v2",
"created": "Sun, 29 Apr 2007 10:18:17 GMT"
}
] | 2008-10-27T00:00:00 | [
[
"Biltmo",
"A.",
""
],
[
"Henelius",
"P.",
""
]
] |
0704.3657 | Mark Dennis | Mark R. Dennis, Kate Land | Probability Density of the Multipole Vectors for a Gaussian Cosmic
Microwave Background | 12 pages, 7 figures, MNRAS style | null | 10.1111/j.1365-2966.2007.12484.x | null | astro-ph math-ph math.MP | null | We review Maxwell's multipole vectors, and elucidate some of their
mathematical properties, with emphasis on the application of this tool to the
cosmic microwave background (CMB). In particular, for a completely random
function on the sphere (corresponding to the statistically isotropic Gaussian
model of the CMB), we derive the full probability density function of the
multipole vectors. This function is used to analyze the internal configurations
of the third-year Wilkinson Microwave Anisotropy Probe quadrupole and octopole,
and we show the observations are consistent with the Gaussian prediction. A
particular aspect is the planarity of the octopole, which we find not to be
anomalous.
| [
{
"version": "v1",
"created": "Fri, 27 Apr 2007 18:48:17 GMT"
},
{
"version": "v2",
"created": "Thu, 9 Aug 2007 15:24:04 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Dennis",
"Mark R.",
""
],
[
"Land",
"Kate",
""
]
] |
0704.3658 | Katsunori Kawamura | Katsunori Kawamura | Recursive boson system in the Cuntz algebra ${\cal O}_{\infty}$ | 18 pp | null | 10.1063/1.2759838 | null | math.OA | null | Bosons and fermions are often written by elements of other algebras. M. Abe
gave a recursive realization of the boson by formal infinite sums of the
canonical generators of the Cuntz algebra ${\cal O}_{\infty}$. We show that
such formal infinite sum always makes sense on a certain dense subspace of any
permutative representation of ${\cal O}_{\infty}$. In this meaning, we can
regard as if the algebra ${\cal B}$ of bosons was a unital $*$-subalgebra of
${\cal O}_{\infty}$ on a given permutative representation by keeping their
unboundedness. By this relation, we compute branching laws arising from
restrictions of representations of ${\cal O}_{\infty}$ on ${\cal B}$. For
example, it is shown that the Fock representation of ${\cal B}$ is given as the
restriction of the standard representation of ${\cal O}_{\infty}$ on ${\cal
B}$.
| [
{
"version": "v1",
"created": "Fri, 27 Apr 2007 04:32:51 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Kawamura",
"Katsunori",
""
]
] |
0704.3659 | Haruhiko Terao | Haruhiko Terao and Akito Tsuchiya | Conformal dynamics in gauge theories via non-perturbative
renormalization group | 27 pages, 12 Postscript figures, corrected typos and references | null | null | Kanazawa-07-04 | hep-ph | null | The dynamics at the IR fixed point realized in the $SU(N_c)$ gauge theories
with massless Dirac fermions is studied by means of the non-perturbative
renormalization group. The analysis includes the IR fixed points with
non-trivial Yukawa couplings. The renormalization properties of the scalar
field are also discussed and it is shown that hierarchical mass scale may be
allowed without intense fine-tuning due to a large anomalous dimension.
| [
{
"version": "v1",
"created": "Fri, 27 Apr 2007 05:10:48 GMT"
},
{
"version": "v2",
"created": "Fri, 19 Oct 2007 04:55:50 GMT"
}
] | 2011-11-09T00:00:00 | [
[
"Terao",
"Haruhiko",
""
],
[
"Tsuchiya",
"Akito",
""
]
] |
0704.3660 | A. V. Syromyatnikov | A. V. Syromyatnikov | Nonfrustrated magnetoelectric with incommensurate magnetic order in
magnetic field | 12 pages, 3 figures, accepted in JETP | JETP 105, 587 (2007) | 10.1134/S1063776107090154 | null | cond-mat.str-el | null | We discuss a model nonfrustrated magnetoelectric in which strong enough
magnetoelectric coupling produces incommensurate magnetic order leading to
ferroelectricity. Properties of the magnetoelectric in magnetic field directed
perpendicular to wave vector describing the spin helix are considered in
detail. Analysis of classical energy shows that in contrast to naive
expectation the onset of ferroelectricity takes place at a field $H_{c1}$ that
is lower than the saturation field $H_{c2}$. One has $H_{c1}=H_{c2}$ at strong
enough magnetoelectric coupling. We show that at H=0 the ferroelectricity
appears at $T=T_{FE}<T_N$. Qualitative discussion of phase diagram in $H-T$
plane is presented within mean field approach.
| [
{
"version": "v1",
"created": "Fri, 27 Apr 2007 05:57:03 GMT"
}
] | 2007-10-22T00:00:00 | [
[
"Syromyatnikov",
"A. V.",
""
]
] |
0704.3661 | Masato Koashi | Masato Koashi | Complementarity, distillable secret key, and distillable entanglement | 4 pages, 2 figures | null | null | null | quant-ph | null | We consider controllability of two conjugate observables Z and X by two
parties with classical communication. The ability is specified by two
alternative tasks, (i) agreement on Z and (ii) preparation of an eigenstate of
X with use of an extra communication channel. We prove that their feasibility
is equivalent to that of key distillation if the extra channel is quantum, and
to that of entanglement distillation if it is classical. This clarifies the
distinction between two entanglement measures, distillable key and distillable
entanglement.
| [
{
"version": "v1",
"created": "Fri, 27 Apr 2007 05:29:58 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Koashi",
"Masato",
""
]
] |
0704.3662 | Tian-Jian Jiang | Mike Tian-Jian Jiang, James Zhan, Jaimie Lin, Jerry Lin, Wen-Lien Hsu | An Automated Evaluation Metric for Chinese Text Entry | 8 pages | Jiang, Mike Tian-Jian, et al. "Robustness analysis of adaptive
chinese input methods." Advances in Text Input Methods (WTIM 2011) (2011): 53 | null | null | cs.HC cs.CL | null | In this paper, we propose an automated evaluation metric for text entry. We
also consider possible improvements to existing text entry evaluation metrics,
such as the minimum string distance error rate, keystrokes per character, cost
per correction, and a unified approach proposed by MacKenzie, so they can
accommodate the special characteristics of Chinese text. Current methods lack
an integrated concern about both typing speed and accuracy for Chinese text
entry evaluation. Our goal is to remove the bias that arises due to human
factors. First, we propose a new metric, called the correction penalty (P),
based on Fitts' law and Hick's law. Next, we transform it into the approximate
amortized cost (AAC) of information theory. An analysis of the AAC of Chinese
text input methods with different context lengths is also presented.
| [
{
"version": "v1",
"created": "Fri, 27 Apr 2007 05:34:10 GMT"
}
] | 2013-10-29T00:00:00 | [
[
"Jiang",
"Mike Tian-Jian",
""
],
[
"Zhan",
"James",
""
],
[
"Lin",
"Jaimie",
""
],
[
"Lin",
"Jerry",
""
],
[
"Hsu",
"Wen-Lien",
""
]
] |
0704.3663 | Alexey Kalachev | Alexey Kalachev | Quantum storage on subradiant states in an extended atomic ensemble | V2: considerably revised (title, text). V3: minor changes - final
version as published in PRA | Phys. Rev. A 76, 043812 (2007) | 10.1103/PhysRevA.76.043812 | null | quant-ph | null | A scheme for coherent manipulation of collective atomic states is developed
such that total subradiant states, in which spontaneous emission is suppressed
into all directions due to destructive interference between neighbor atoms, can
be created in an extended atomic ensemble. The optimal conditions for creation
of such states and suitability of them for quantum storage are discussed. It is
shown that in order to achieve the maximum signal-to-noise ratio the shape of a
light pulse to be stored and reconstructed using a homogeneously broadened
absorbtion line of an atomic system should be a time-reversed regular part of
the response function of the system. In the limit of high optical density, such
pulses allow one to prepare collective subradiant atomic states with near flat
spatial distribution of the atomic excitation in the medium.
| [
{
"version": "v1",
"created": "Fri, 27 Apr 2007 05:43:00 GMT"
},
{
"version": "v2",
"created": "Fri, 8 Jun 2007 15:28:15 GMT"
},
{
"version": "v3",
"created": "Sun, 6 Apr 2008 20:10:27 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Kalachev",
"Alexey",
""
]
] |
0704.3664 | Kanishev Konstantin | I. F. Ginzburg, K.A. Kanishev | Different vacua in 2HDM | 24 pages, 3 figures | Phys.Rev.D76:095013,2007 | 10.1103/PhysRevD.76.095013 | null | hep-ph | null | We discuss the extrema of the Two Higgs Doublet Model with different physical
properties. We have found necessary and sufficient conditions for realization
of the extrema with different properties as the vacuum state of the model. We
found explicit equations for extremum energies via parameters of potential if
it has explicitly CP conserving form. These equations allow to pick out
extremum with lower energy -- vacuum state and to look for change of extrema
(phase transitions) with the variation of parameters of potential. Our goal is
to find general picture here to apply it for description of early Universe.
| [
{
"version": "v1",
"created": "Fri, 27 Apr 2007 05:43:20 GMT"
},
{
"version": "v2",
"created": "Mon, 2 Jul 2007 09:46:22 GMT"
},
{
"version": "v3",
"created": "Mon, 14 Jan 2008 09:59:10 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Ginzburg",
"I. F.",
""
],
[
"Kanishev",
"K. A.",
""
]
] |
0704.3665 | Tian-Jian Jiang | Mike Tian-Jian Jiang, Deng Liu, Meng-Juei Hsieh, Wen-Lien Hsu | On the Development of Text Input Method - Lessons Learned | 10 pages | null | null | null | cs.CL cs.HC | null | Intelligent Input Methods (IM) are essential for making text entries in many
East Asian scripts, but their application to other languages has not been fully
explored. This paper discusses how such tools can contribute to the development
of computer processing of other oriental languages. We propose a design
philosophy that regards IM as a text service platform, and treats the study of
IM as a cross disciplinary subject from the perspectives of software
engineering, human-computer interaction (HCI), and natural language processing
(NLP). We discuss these three perspectives and indicate a number of possible
future research directions.
| [
{
"version": "v1",
"created": "Fri, 27 Apr 2007 05:58:32 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Jiang",
"Mike Tian-Jian",
""
],
[
"Liu",
"Deng",
""
],
[
"Hsieh",
"Meng-Juei",
""
],
[
"Hsu",
"Wen-Lien",
""
]
] |
0704.3666 | Nobuhiko Yokoshi | Nobuhiko Yokoshi, Susumu Kurihara | AC Josephson current and supercurrent noise through one-dimensional
correlated electron systems | 5 pages, 1 figure | Physc. Rev. B 76, 144509 (2007) | 10.1103/PhysRevB.76.144509 | null | cond-mat.mes-hall cond-mat.supr-con | null | AC Josephson effect in one-dimensional Tomonaga-Luttinger liquid (TLL)
adiabatically connected to superconducting electrodes is theoretically
investigated. It is found that density fluctuations due to repulsive
electron-electron interactions in TLL inhibit Josephson oscillations, whereas
they do not affect time-independent current part. We also show that the
fluctuations reduce supercurrent noise caused by multiple Andreev reflections.
This indicates that the quantum fluctuations in TLL disturb the superconducting
phase coherence spreading across the junction.
| [
{
"version": "v1",
"created": "Fri, 27 Apr 2007 06:28:48 GMT"
},
{
"version": "v2",
"created": "Tue, 28 Aug 2007 04:28:24 GMT"
},
{
"version": "v3",
"created": "Mon, 22 Oct 2007 07:46:02 GMT"
}
] | 2007-10-22T00:00:00 | [
[
"Yokoshi",
"Nobuhiko",
""
],
[
"Kurihara",
"Susumu",
""
]
] |
0704.3667 | Martin B. Halpern | M.B.Halpern | The Orbifolds of Permutation-Type as Physical String Systems at
Multiples of c=26 IV. Orientation Orbifolds Include Orientifolds | 22 pages, typos corrected | Phys.Rev.D76:026004,2007 | 10.1103/PhysRevD.76.026004 | null | hep-th math-ph math.MP | null | In this fourth paper of the series, I clarify the somewhat mysterious
relation between the large class of {\it orientation orbifolds} (with twisted
open-string CFT's at $\hat c=52$) and {\it orientifolds} (with untwisted open
strings at $c=26$), both of which have been associated to division by
world-sheet orientation-reversing automorphisms. In particular -- following a
spectral clue in the previous paper -- I show that, even as an {\it interacting
string system}, a certain half-integer-moded orientation orbifold-string system
is in fact equivalent to the archetypal orientifold. The subtitle of this
paper, that orientation orbifolds include and generalize standard orientifolds,
then follows because there are many other orientation orbifold-string systems
-- with higher fractional modeing -- which are not equivalent to untwisted
string systems.
| [
{
"version": "v1",
"created": "Fri, 27 Apr 2007 06:44:54 GMT"
},
{
"version": "v2",
"created": "Fri, 6 Jul 2007 05:55:15 GMT"
},
{
"version": "v3",
"created": "Mon, 31 Dec 2007 08:50:55 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Halpern",
"M. B.",
""
]
] |
0704.3668 | Johann Haidenbauer | J. Haidenbauer, G. Krein, Ulf-G. Mei{\ss}ner, A. Sibirtsev | Dbar-N interaction from meson-exchange and quark-gluon dynamics | 11 pages, 7 figures | Eur.Phys.J.A33:107-117,2007 | 10.1140/epja/i2007-10417-3 | FZJ-IKP-TH-2007-15 | nucl-th hep-ph | null | We investigate the Dbar-N interaction at low energies using a meson-exchange
model supplemented with a short-distance contribution from one-gluon-exchange.
The model is developed in close analogy to the meson-exchange KN interaction of
the Juelich group utilizing SU(4) symmetry constraints. The main ingredients of
the interaction are provided by vector meson (rho, omega) exchange and
higher-order box diagrams involving D*N, D\Delta, and D*\Delta intermediate
states. The short range part is assumed to receive additional contributions
from genuine quark-gluon processes. The predicted cross sections for Dbar-N for
excess energies up to 150 MeV are of the same order of magnitude as those for
KN but with average values of around 20 mb, roughly a factor two larger than
for the latter system. It is found that the omega-exchange plays a very
important role. Its interference pattern with the rho-exchange, which is
basically fixed by the assumed SU(4) symmetry, clearly determines the
qualitative features of the Dbar-N interaction -- very similiar to what happens
also for the KN system.
| [
{
"version": "v1",
"created": "Fri, 27 Apr 2007 07:00:49 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Haidenbauer",
"J.",
""
],
[
"Krein",
"G.",
""
],
[
"Meißner",
"Ulf-G.",
""
],
[
"Sibirtsev",
"A.",
""
]
] |
0704.3669 | Anna Beliakova | Anna Beliakova, Christian Blanchet, Thang T. Q. Le | Unified quantum invariants and their refinements for homology 3-spheres
with 2-torsion | 23 pages, results of math.QA/0510382 are included | Fund. math., 201 (2008), pp. 217-239 | null | null | math.QA math.GT | null | For every rational homology 3-sphere with 2-torsion only we construct a
unified invariant (which takes values in a certain cyclotomic completion of a
polynomial ring), such that the evaluation of this invariant at any odd root of
unity provides the SO(3) Witten-Reshetikhin-Turaev invariant at this root and
at any even root of unity the SU(2) quantum invariant. Moreover, this unified
invariant splits into a sum of the refined unified invariants dominating spin
and cohomological refinements of quantum SU(2) invariants. New results on the
Ohtsuki series and the integrality of quantum invariants are the main
applications of our construction.
| [
{
"version": "v1",
"created": "Fri, 27 Apr 2007 07:12:16 GMT"
}
] | 2014-04-14T00:00:00 | [
[
"Beliakova",
"Anna",
""
],
[
"Blanchet",
"Christian",
""
],
[
"Le",
"Thang T. Q.",
""
]
] |
0704.3670 | Baorong Chang | Baorong Chang, Hongya Liu, Lixin Xu and Chengwu Zhang | Statefinder Parameters for Five-Dimensional Cosmology | 8 pages, 12 figures. accepted by MPLA | Mod.Phys.Lett.A23:269-279,2008 | 10.1142/S0217732308023694 | null | astro-ph | null | We study the statefinder parameter in the five-dimensional big bounce model,
and apply it to differentiate the attractor solutions of quintessence and
phantom field. It is found that the evolving trajectories of these two
attractor solutions in the statefinder parameters plane are quite different,
and that are different from the statefinder trajectories of other dark energy
models.
| [
{
"version": "v1",
"created": "Fri, 27 Apr 2007 07:01:55 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"Chang",
"Baorong",
""
],
[
"Liu",
"Hongya",
""
],
[
"Xu",
"Lixin",
""
],
[
"Zhang",
"Chengwu",
""
]
] |
0704.3671 | Ricardo Doretto | R. L. Doretto and C. Morais Smith | Quantum Hall ferromagnetism in graphene: a SU(4) bosonization approach | 16 pages, 4 figures, final version, extended discussion about the
boson-boson interaction and its relation with quantum Hall skyrmions | Phys. Rev. B 76, 195431 (2007) | 10.1103/PhysRevB.76.195431 | null | cond-mat.mes-hall cond-mat.str-el | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We study the quantum Hall effect in graphene at filling factors \nu = 0 and
\nu = \pm, concentrating on the quantum Hall ferromagnetic regime, within a
non-perturbative bosonization formalism. We start by developing a bosonization
scheme for electrons with two discrete degrees of freedom (spin-1/2 and
pseudospin-1/2) restricted to the lowest Landau level. Three distinct phases
are considered, namely the so-called spin-pseudospin, spin, and pseudospin
phases. The first corresponds to a quarter-filled (\nu =-1) while the others to
a half-filled (\nu = 0) lowest Landau level. In each case, we show that the
elementary neutral excitations can be treated approximately as a set of
n-independent kinds of boson excitations. The boson representation of the
projected electron density, the spin, pseudospin, and mixed spin-pseudospin
density operators are derived. We then apply the developed formalism to the
effective continuous model, which includes SU(4) symmetry breaking terms,
recently proposed by Alicea and Fisher. For each quantum Hall state, an
effective interacting boson model is derived and the dispersion relations of
the elementary excitations are analytically calculated. We propose that the
charged excitations (quantum Hall skyrmions) can be described as a coherent
state of bosons. We calculate the semiclassical limit of the boson model
derived from the SU(4) invariant part of the original fermionic Hamiltonian and
show that it agrees with the results of Arovas and co-workers for SU(N) quantum
Hall skyrmions. We briefly discuss the influence of the SU(4) symmetry breaking
terms in the skyrmion energy.
| [
{
"version": "v1",
"created": "Fri, 27 Apr 2007 18:50:30 GMT"
},
{
"version": "v2",
"created": "Fri, 14 Nov 2008 12:22:13 GMT"
}
] | 2008-11-14T00:00:00 | [
[
"Doretto",
"R. L.",
""
],
[
"Smith",
"C. Morais",
""
]
] |
0704.3672 | Dhananjay Mehendale | Dhananjay P. Mehendale | Hamiltonian Graphs and the Traveling Salesman Problem | 44 pages. Subsection 2.7.4 is revised, added two new search
algorithms and illustrative examples | null | null | null | math.GM | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | A new characterisation of Hamiltonian graphs using f-cutset matrix is
proposed. A new exact polynomial time algorithm for the travelling salesman
problem (TSP) based on this new characterisation is developed. We then define
so called ordered weighted adjacency list for given weighted complete graph and
proceed to the main result of the paper, namely, the exact algorithm based on
utilisation of ordered weighted adjacency list and the simple properties that
any path or circuit must satisfy. This algorithm performs checking of
sub-lists, containing (p-1) entries (edge pairs) for paths and p entries (edge
pairs) for circuits, chosen from ordered adjacency list in a well defined
sequence to determine exactly the shortest Hamiltonian path and shortest
Hamiltonian circuit in a weighted complete graph of p vertices. The procedure
has intrinsic advantage of landing on the desired solution in quickest possible
time and even in worst case in polynomial time. A new characterisation of
shortest Hamiltonian tour for a weighted complete graph satisfying triangle
inequality (i.e. for tours passing through every city on a realistic map of
cities where cities can be taken as points on a Euclidean plane) is also
proposed. Finally, we propose a classical algorithm for unstructured search and
also three new quantum algorithms for unstructured search which exponentially
speed up the searching ability in the unstructured database and discuss its
effect on the NP-Complete problems.
| [
{
"version": "v1",
"created": "Fri, 27 Apr 2007 11:31:03 GMT"
},
{
"version": "v10",
"created": "Mon, 11 Jul 2016 17:11:24 GMT"
},
{
"version": "v2",
"created": "Wed, 9 May 2007 11:35:39 GMT"
},
{
"version": "v3",
"created": "Sun, 13 May 2007 11:08:00 GMT"
},
{
"version": "v4",
"created": "Mon, 31 Mar 2008 12:54:58 GMT"
},
{
"version": "v5",
"created": "Tue, 14 Oct 2008 10:28:56 GMT"
},
{
"version": "v6",
"created": "Mon, 1 Apr 2013 07:51:30 GMT"
},
{
"version": "v7",
"created": "Thu, 11 Apr 2013 20:06:47 GMT"
},
{
"version": "v8",
"created": "Sun, 23 Jun 2013 10:23:08 GMT"
},
{
"version": "v9",
"created": "Tue, 24 May 2016 18:46:51 GMT"
}
] | 2016-07-12T00:00:00 | [
[
"Mehendale",
"Dhananjay P.",
""
]
] |
0704.3673 | Brian M. Andersen | Brian M. Andersen, P. J. Hirschfeld, James A. Slezak | Superconducting gap variations induced by structural supermodulation in
BSCCO | 4 pages, 3 figures | Phys. Rev. B 76, 020507 (2007) | 10.1103/PhysRevB.76.020507 | null | cond-mat.supr-con cond-mat.str-el | null | We discuss the possibility that the strain field introduced by the structural
supermodulation in Bi-2212 and certain other cuprate materials may modulate the
superconducting pairing interaction. We calculate the amplitude of this effect,
visible in scanning tunneling spectroscopy experiments, and thereby relate a
change in the local superconducting gap with the change in the local dopant
displacements induced by the supermodulation. In principle, since this
modulation is periodic, sufficiently accurate x-ray measurements or ab initio
calculations should enable one to determine which atomic displacements enhance
pairing and therefore T_c.
| [
{
"version": "v1",
"created": "Fri, 27 Apr 2007 11:51:38 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Andersen",
"Brian M.",
""
],
[
"Hirschfeld",
"P. J.",
""
],
[
"Slezak",
"James A.",
""
]
] |
0704.3674 | Wolfgang Steiner | Shigeki Akiyama, Horst Brunotte, Attila Petho, Wolfgang Steiner
(LIAFA) | Periodicity of certain piecewise affine planar maps | null | Tsukuba Journal of Mathematics 32, 1 (2008) 197-251 | null | null | math.DS cs.DM math.NT | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We determine periodic and aperiodic points of certain piecewise affine maps
in the Euclidean plane. Using these maps, we prove for
$\lambda\in\{\frac{\pm1\pm\sqrt5}2,\pm\sqrt2,\pm\sqrt3\}$ that all integer
sequences $(a_k)_{k\in\mathbb Z}$ satisfying $0\le a_{k-1}+\lambda
a_k+a_{k+1}<1$ are periodic.
| [
{
"version": "v1",
"created": "Fri, 27 Apr 2007 12:07:24 GMT"
},
{
"version": "v2",
"created": "Mon, 30 Jul 2007 09:24:43 GMT"
},
{
"version": "v3",
"created": "Tue, 16 Sep 2008 11:43:27 GMT"
}
] | 2008-09-16T00:00:00 | [
[
"Akiyama",
"Shigeki",
"",
"LIAFA"
],
[
"Brunotte",
"Horst",
"",
"LIAFA"
],
[
"Petho",
"Attila",
"",
"LIAFA"
],
[
"Steiner",
"Wolfgang",
"",
"LIAFA"
]
] |
0704.3675 | Koraljka Mu\v{z}i\'c | K. Muzic, A. Eckart, R. Schoedel, L. Meyer, A. Zensus | First proper motions of thin dust filaments at the Galactic Center | accepted for publication by A&A | null | 10.1051/0004-6361:20066265 | null | astro-ph | null | Context: L'-band (3.8 micron) images of the Galactic Center show a large
number of thin filaments in the mini-spiral, located west of the mini-cavity
and along the inner edge of the Northern Arm. One possible mechanism that could
produce such structures is the interaction of a central wind with the
mini-spiral. Additionally, we identify similar features that appear to be
associated with stars. Aims: We present the first proper motion measurements of
the thin dust filaments observed in the central parsec around SgrA* and
investigate possible mechanisms that could be responsible for the observed
motions. Methods: The observations have been carried out using the NACO
adaptive optics system at the ESO VLT. The images have been transformed to a
common coordinate system and features of interest were extracted. Then a
cross-correlation technique could be performed in order to determine the
offsets between the features with respect to their position in the reference
epoch. Results: We derive the proper motions of a number of filaments and 2
cometary shaped dusty sources close (in projection) to SgrA*. We show that the
shape and the motion of the filaments does not agree with a purely Keplerian
motion of the gas in the potential of the supermassive black hole at the
position of SgrA*. Therefore, additional mechanisms must be responsible for
their formation and motion. We argue that the properties of the filaments are
probably related to an outflow from the disk of young mass-losing stars around
SgrA*. In part, the outflow may originate from the black hole itself. We also
present some evidence and theoretical considerations that the outflow may be
collimated.
| [
{
"version": "v1",
"created": "Fri, 27 Apr 2007 15:33:39 GMT"
},
{
"version": "v2",
"created": "Tue, 5 Jun 2007 11:39:47 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Muzic",
"K.",
""
],
[
"Eckart",
"A.",
""
],
[
"Schoedel",
"R.",
""
],
[
"Meyer",
"L.",
""
],
[
"Zensus",
"A.",
""
]
] |
0704.3676 | Suryanarayana V.S. Saraswatula | S. V. Suryanarayana | Virtual Photon Emission from Quark-Gluon Plasma | 8 pages 8 figures, phenomenological formulae for photon emission | Phys.Rev.C76:044903,2007 | 10.1103/PhysRevC.76.044903 | null | hep-ph | null | We recently proposed an empirical approach for the Landau-Pomeranchuk-Migdal
(LPM) effects in photon emission from the quark gluon plasma as a function of
photon mass. This approach was based on Generalized Emission Functions (GEF)
for photon emission, derived at a fixed temperature and strong coupling
constant. In the present work, we have extended the LPM calculations for
several temperatures and strong coupling strengths. The integral equations for
(${\bf \tilde{f}(\tilde{p}_\perp)}$) and ($\tilde{g}({\bf \tilde{p}_\perp})$)
are solved by the iterations method for the variable set
\{$p_0,q_0,Q^2,T,\alpha_s$\}, considering bremsstrahlung and $\bf aws$
processes. We generalize the dynamical scaling variables, $x_T$, $x_L$, for
bremsstrahlung and {\bf aws} processes which are now functions of variables
$p_0,q_0,Q^2,T,\alpha_s$. The GEF introduced earlier, $g^b_T$, $g^a_T$,
$g^b_L$, $g^a_L$, are also generalized for any temperatures and coupling
strengths. From this, the imaginary part of the photon polarization tensor as a
function of photon mass and energy can be calculated as a one dimensional
integral over these GEF and parton distribution functions in the plasma.
However, for phenomenological studies of experimental data, one needs a simple
empirical formula without involving parton momentum integrations. Therefore, we
present a phenomenological formula for imaginary photon polarization tensor as
a function of \{$q_0,Q^2,T,\alpha_s$\} that includes bremsstrahlung and $\bf
aws$ mechanisms along with LPM effects.
| [
{
"version": "v1",
"created": "Fri, 27 Apr 2007 12:37:33 GMT"
},
{
"version": "v2",
"created": "Sat, 28 Apr 2007 05:12:29 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Suryanarayana",
"S. V.",
""
]
] |
0704.3677 | Pulak Ranjan Giri | Pulak Ranjan Giri | Optimal time evolution in (non)hermitian quantum mechanics | Withdrawn | null | null | null | hep-th | null | This paper has been withdrawn by the author
| [
{
"version": "v1",
"created": "Fri, 27 Apr 2007 12:49:56 GMT"
},
{
"version": "v2",
"created": "Mon, 30 Apr 2007 18:20:41 GMT"
},
{
"version": "v3",
"created": "Tue, 22 May 2007 10:00:51 GMT"
}
] | 2008-01-08T00:00:00 | [
[
"Giri",
"Pulak Ranjan",
""
]
] |
0704.3678 | Coralie Doucet Mrs | Doucet, C.(1), Habart, E (2), Pantin, E.(1), Dullemond, C.(3), Lagage,
P-O (1), Pinte, C.(4), Duch\^ene, G.(4), M\'enard, F.(4) ((1)
DSM/DAPNIA/service d'Astrophysique, CEA/Saclay, Gif-sur-Yvette, France, (2)
Institut d'Astrophysique Spatiale (IAS), Orsay cedex, France, (3)
Max-Planck-Institut fur Astronomie Heidelberg, Heidelberg, Germany, (4)
Laboratoire d'Astrophysique de Grenoble, Grenoble, France) | HD97048: a closer look to the disk | accepted in A&A, 8 pages, 8 figures | null | null | null | astro-ph | null | Aims: Today, large ground-based instruments, like VISIR on the VLT, providing
diffraction-limited (about 0.3 arcsec) images in the mid-infrared where strong
PAH features appear enable us to see the flaring structure of the disks around
Herbig Ae stars.
Although great progress has been made in modelling the disk with radiative
transfer models able to reproduce the spectral energy distribution (SED) of
Herbig Ae stars, the constraints brought by images have not been yet fully
exploited. Here, we are interested in checking if these new observational
imaging constraints can be accounted for by predictions based on existing
models of passive centrally irradiated hydrostatic disks made to fit the SEDs
of the Herbig Ae stars.
Methods: The images taken by VISIR in the 8.6 and 11.3 microns aromatic
features reveal a large flaring disk around HD97048 inclined to the line of
sight. In order to analyse the spatial distribution of these data, we use a
disk model which includes the most up to date understanding of disk structure
and physics around Herbig Ae stars with grains in thermal equilibrium in
addition to transiently-heated PAHs.
Results: We compare the observed spatial distribution of the PAH emission
feature and the adjacent continuum emission with predictions based on existing
full disk models. Both SED and spatial distribution are in very good agreement
with the model predictions for common disk parameters.
Conclusions: We take the general agreement between observations and
predictions as a strong support for the physical pictures underlying our flared
disk model.
| [
{
"version": "v1",
"created": "Fri, 27 Apr 2007 12:48:18 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Doucet",
"",
""
],
[
"C.",
"",
""
],
[
"Habart",
"",
""
],
[
"E",
"",
""
],
[
"Pantin",
"",
""
],
[
"E.",
"",
""
],
[
"Dullemond",
"",
""
],
[
"C.",
"",
""
],
[
"Lagage",
"",
""
],
[
"P-O",
"",
""
],
[
"Pinte",
"",
""
],
[
"C.",
"",
""
],
[
"Duchêne",
"",
""
],
[
"G.",
"",
""
],
[
"Ménard",
"",
""
],
[
"F.",
"",
""
]
] |
0704.3679 | Mohammad Reza Setare | M R Setare | Holographic Chaplygin gas model | 9 pages, no figures | Phys.Lett.B648:329-332,2007 | 10.1016/j.physletb.2007.03.025 | null | hep-th | null | In this paper we consider a correspondence between the holographic dark
energy density and Chaplygin gas energy density in FRW universe. Then we
reconstruct the potential and the dynamics of the scalar field which describe
the Chaplygin cosmology.
| [
{
"version": "v1",
"created": "Fri, 27 Apr 2007 12:50:52 GMT"
}
] | 2010-10-27T00:00:00 | [
[
"Setare",
"M R",
""
]
] |
0704.3680 | Yusuke Kozuka | Y. Kozuka, Y. Hikita, T. Susaki, H. Y. Hwang | Optically tuned dimensionality crossover in photocarrier-doped
SrTiO$_3$: onset of weak localization | 7 pages, 7 figures | null | 10.1103/PhysRevB.76.085129 | null | cond-mat.str-el | null | We report magnetotransport properties of photogenerated electrons in undoped
SrTiO$_3$ single crystals under ultraviolet illumination down to 2 K. By tuning
the light intensity, the steady state carrier density can be controlled, while
tuning the wavelength controls the effective electronic thickness by modulating
the optical penetration depth. At short wavelengths, when the sheet conductance
is close to the two-dimensional Mott minimum conductivity we have observed
critical behavior characteristic of weak localization. Negative
magnetoresistance at low magnetic field is highly anisotropic, indicating
quasi-two-dimensional electronic transport. The high mobility of photogenerated
electrons in SrTiO$_3$ allows continuous tuning of the effective electronic
dimensionality by photoexcitation.
| [
{
"version": "v1",
"created": "Fri, 27 Apr 2007 13:03:56 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Kozuka",
"Y.",
""
],
[
"Hikita",
"Y.",
""
],
[
"Susaki",
"T.",
""
],
[
"Hwang",
"H. Y.",
""
]
] |
0704.3681 | Nirupam Roy | Nirupam Roy, Arnab K. Ray | Critical properties of spherically symmetric accretion in a fractal
medium | 9 pages, 4 figures. Accepted for publication in MNRAS. The definitive
version is available at http://www.blackwell-synergy.com | 2007, MNRAS, 380, 733 | 10.1111/j.1365-2966.2007.12108.x | null | astro-ph | null | Spherically symmetric transonic accretion of a fractal medium has been
studied in both the stationary and the dynamic regimes. The stationary
transonic solution is greatly sensitive to infinitesimal deviations in the
outer boundary condition, but the flow becomes transonic and stable, when its
evolution is followed through time. The evolution towards transonicity is more
pronounced for a fractal medium than what is it for a continuum. The dynamic
approach also shows that there is a remarkable closeness between an equation of
motion for a perturbation in the flow, and the metric of an analogue acoustic
black hole. The stationary inflow solutions of a fractal medium are as much
stable under the influence of linearised perturbations, as they are for the
fluid continuum.
| [
{
"version": "v1",
"created": "Fri, 27 Apr 2007 13:05:22 GMT"
},
{
"version": "v2",
"created": "Wed, 18 Jul 2007 20:50:30 GMT"
}
] | 2007-08-30T00:00:00 | [
[
"Roy",
"Nirupam",
""
],
[
"Ray",
"Arnab K.",
""
]
] |
0704.3682 | Nicola Masetti | N. Masetti, R. Landi, M.L. Pretorius, V. Sguera, A.J. Bird, M. Perri,
P.A. Charles, J.A. Kennea, A. Malizia and P. Ubertini | IGR J16194-2810: a new symbiotic X-ray binary | 9 pages, 4 figures, 3 tables. Accepted for publication on Astronomy &
Astrophysics, main journal. Slight changes to match the proof-corrected
version: Pdot/P for 4U 1954+31 (in Table 3) corrected; acknowledgements
expanded; references updated | null | 10.1051/0004-6361:20077509 | null | astro-ph | null | We here report on the multiwavelength study which led us to the
identification of X-ray source IGR J16194-2810 as a new Symbiotic X-ray Binary
(SyXB), that is, a rare type of Low Mass X-ray Binary (LMXB) composed of a
M-type giant and a compact object. Using the accurate X-ray position allowed by
Swift/XRT data, we pinpointed the optical counterpart, a M2 III star. Besides,
the combined use of the spectral information afforded by XRT and INTEGRAL/IBIS
shows that the 0.5-200 keV spectrum of this source can be described with an
absorbed Comptonization model, usually found in LMXBs and, in particular, in
SyXBs. No long-term (days to months) periodicities are detected in the IBIS
data. The time coverage afforded by XRT reveals shot-noise variability typical
of accreting Galactic X-ray sources, but is not good enough to explore the
presence of X-ray short-term (seconds to hours) oscillations in detail. By
using the above information, we infer important parameters for this source such
as its distance (about 3.7 kpc) and X-ray luminosity (about 1.4e35 erg/s in the
0.5-200 keV band), and we give a description for this system (typical of SyXBs)
in which a compact object (possibly a neutron star) accretes from the wind of
its M-type giant companion. We also draw some comparisons between IGR
J16194-2810 and other sources belonging to this subclass, finding that this
object resembles SyXBs 4U 1700+24 and 4U 1954+31.
| [
{
"version": "v1",
"created": "Fri, 27 Apr 2007 17:58:04 GMT"
},
{
"version": "v2",
"created": "Fri, 22 Jun 2007 03:43:59 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Masetti",
"N.",
""
],
[
"Landi",
"R.",
""
],
[
"Pretorius",
"M. L.",
""
],
[
"Sguera",
"V.",
""
],
[
"Bird",
"A. J.",
""
],
[
"Perri",
"M.",
""
],
[
"Charles",
"P. A.",
""
],
[
"Kennea",
"J. A.",
""
],
[
"Malizia",
"A.",
""
],
[
"Ubertini",
"P.",
""
]
] |
0704.3683 | Mark Jerrum | Martin Dyer, Leslie Ann Goldberg and Mark Jerrum | The Complexity of Weighted Boolean #CSP | Minor revision | SIAM J. Comput. 38(5), 1970-1986 | 10.1137/070690201 | null | cs.CC math.CO | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | This paper gives a dichotomy theorem for the complexity of computing the
partition function of an instance of a weighted Boolean constraint satisfaction
problem. The problem is parameterised by a finite set F of non-negative
functions that may be used to assign weights to the configurations (feasible
solutions) of a problem instance. Classical constraint satisfaction problems
correspond to the special case of 0,1-valued functions. We show that the
partition function, i.e. the sum of the weights of all configurations, can be
computed in polynomial time if either (1) every function in F is of ``product
type'', or (2) every function in F is ``pure affine''. For every other fixed
set F, computing the partition function is FP^{#P}-complete.
| [
{
"version": "v1",
"created": "Fri, 27 Apr 2007 13:19:32 GMT"
},
{
"version": "v2",
"created": "Thu, 19 Jun 2008 08:00:54 GMT"
}
] | 2009-02-23T00:00:00 | [
[
"Dyer",
"Martin",
""
],
[
"Goldberg",
"Leslie Ann",
""
],
[
"Jerrum",
"Mark",
""
]
] |
0704.3684 | Patrick Maletinsky M | P. Maletinsky, A. Badolato and A. Imamoglu | Dynamics of Quantum Dot Nuclear Spin Polarization Controlled by a Single
Electron | 5 pages, 3 figures | Phys. Rev. Lett. 99, 056804 (2007) | 10.1103/PhysRevLett.99.056804 | null | physics.optics cond-mat.mes-hall quant-ph | null | We present an experimental study of the dynamics underlying the buildup and
decay of dynamical nuclear spin polarization in a single semiconductor quantum
dot. Our experiment shows that the nuclei can be polarized on a time scale of a
few milliseconds, while their decay dynamics depends drastically on external
parameters. We show that a single electron can very efficiently depolarize the
nuclear spins and discuss two processes that can cause this depolarization.
Conversely, in the absence of a quantum dot electron, the lifetime of nuclear
spin polarization is on the time scale of a second, most likely limited by the
non-secular terms of the nuclear dipole-dipole interaction. We can further
suppress this depolarization rate by 1-2 orders of magnitude by applying an
external magnetic field exceeding 1 mT.
| [
{
"version": "v1",
"created": "Fri, 27 Apr 2007 14:32:02 GMT"
}
] | 2007-08-02T00:00:00 | [
[
"Maletinsky",
"P.",
""
],
[
"Badolato",
"A.",
""
],
[
"Imamoglu",
"A.",
""
]
] |
0704.3685 | Manfred Sch\"ussler | V. Holzwarth, D. Schmitt, M. Schuessler | Flow instabilities of magnetic flux tubes II. Longitudinal flow | accepted by Astronomy & Astrophysics | null | 10.1051/0004-6361:20077269 | null | astro-ph | null | Flow-induced instabilities are relevant for the storage and dynamics of
magnetic fields in stellar convection zones and possibly also in other
astrophysical contexts. We continue the study started in the first paper of
this series by considering the stability properties of longitudinal flows along
magnetic flux tubes. A linear stability analysis was carried out to determine
criteria for the onset of instability in the framework of the approximation of
thin magnetic flux tubes. In the non-dissipative case, we find Kelvin-Helmholtz
instability for flow velocities exceeding a critical speed that depends on the
Alfv{\'e}n speed and on the ratio of the internal and external densities.
Inclusion of a friction term proportional to the relative transverse velocity
leads to a friction-driven instability connected with backward (or negative
energy) waves. We discuss the physical nature of this instability. In the case
of a stratified external medium, the Kelvin-Helmholtz instability and the
friction-driven instability can set in for flow speeds significantly lower than
the Alfv{\'e}n speed. Dissipative effects can excite flow-driven instability
below the thresholds for the Kelvin-Helmholtz and the undulatory (Parker-type)
instabilities. This may be important for magnetic flux storage in stellar
convection zones and for the stability of astrophysical jets.
| [
{
"version": "v1",
"created": "Fri, 27 Apr 2007 14:48:43 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Holzwarth",
"V.",
""
],
[
"Schmitt",
"D.",
""
],
[
"Schuessler",
"M.",
""
]
] |
0704.3686 | Ivan Fernandez-Val | Victor Chernozhukov (MIT), Ivan Fernandez-Val (Boston University),
Alfred Galichon (Harvard University) | Improving Estimates of Monotone Functions by Rearrangement | 31 pages, 8 figures, low resolution figures. This paper has been
withdraw by the authors because it has been replaced by "Improving Point and
Interval Estimates of Monotone Functions by Rearrangement," arXiv:0806.4730 | null | null | null | stat.ME econ.EM math.ST stat.TH | null | Suppose that a target function is monotonic, namely, weakly increasing, and
an original estimate of the target function is available, which is not weakly
increasing. Many common estimation methods used in statistics produce such
estimates. We show that these estimates can always be improved with no harm
using rearrangement techniques: The rearrangement methods, univariate and
multivariate, transform the original estimate to a monotonic estimate, and the
resulting estimate is closer to the true curve in common metrics than the
original estimate. We illustrate the results with a computational example and
an empirical example dealing with age-height growth charts.
| [
{
"version": "v1",
"created": "Fri, 27 Apr 2007 14:49:17 GMT"
},
{
"version": "v2",
"created": "Wed, 3 Nov 2010 13:56:53 GMT"
}
] | 2017-11-23T00:00:00 | [
[
"Chernozhukov",
"Victor",
"",
"MIT"
],
[
"Fernandez-Val",
"Ivan",
"",
"Boston University"
],
[
"Galichon",
"Alfred",
"",
"Harvard University"
]
] |
0704.3687 | Jorge Galindo | Jorge Galindo and Ana-Mar'ia R'odenas | Characterizing group $C^\ast$-algebras through their unitary groups: the
Abelian case | Exposition slightly improved | null | null | null | math.OA math.GN math.GR math.KT | null | We study to what extent group $C^\ast$-algebras are characterized by their
unitary groups. A complete characterization of which Abelian group
$C^\ast$-algebras have isomorphic unitary groups is obtained. We compare these
results with other unitary-related invariants of $C^\ast(\Gamma)$, such as the
$K$-theoretic $K_1(C^\ast(\Gamma))$ and find that $C^\ast$-algebras of
nonisomorphic torsion-free Abelian groups may have isomorphic $K_1$-groups, in
sharp contrast with the well-known fact that $C^\ast(\Gamma)$ (even $\Gamma$)
is characterized by the topological group structure of its unitary group when
$\Gamma $ is torsion-free and Abelian.
| [
{
"version": "v1",
"created": "Fri, 27 Apr 2007 15:06:52 GMT"
},
{
"version": "v2",
"created": "Fri, 28 Sep 2007 11:08:37 GMT"
}
] | 2011-11-09T00:00:00 | [
[
"Galindo",
"Jorge",
""
],
[
"R'odenas",
"Ana-Mar'ia",
""
]
] |
0704.3688 | Roman Gorbachev V | I.Ya. Aref'eva, R.V. Gorbachev, P.B. Medvedev, D.V. Rychkov | Descent Relations in Cubic Superstring Field Theory | Replaced to JHEP style | JHEP0801:005,2008 | 10.1088/1126-6708/2008/01/005 | null | hep-th | null | The descent relations between string field theory (SFT) vertices are
characteristic relations of the operator formulation of SFT and they provide
self-consistency of this theory. The descent relations <V_2|V_1> and <V_3|V_1>
in the NS fermionic string field theory in the kappa and discrete bases are
established. Different regularizations and schemes of calculations are
considered and relations between them are discussed.
| [
{
"version": "v1",
"created": "Fri, 27 Apr 2007 14:53:09 GMT"
},
{
"version": "v2",
"created": "Wed, 11 Jul 2007 14:14:49 GMT"
},
{
"version": "v3",
"created": "Tue, 15 Jan 2008 15:47:28 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Aref'eva",
"I. Ya.",
""
],
[
"Gorbachev",
"R. V.",
""
],
[
"Medvedev",
"P. B.",
""
],
[
"Rychkov",
"D. V.",
""
]
] |
0704.3689 | Shaoyu Yin | Shaoyu Yin and Ru-Keng Su | Thermodynamics of system with density- and/or temperature-dependent mass
particles | 17 pages, 4 figures, 1 table | null | null | null | nucl-th | null | The thermodynamics with medium effects expressed by the dispersion relation
of the temperature and density dependent particle mass is studied. Many
previous treatments have been reviewed. A new thermodynamical treatment based
on the equilibrium state is suggested. Employing the quark mass density- and
temperature-dependent model, the discrepancies between our treatment and others
are addressed.
| [
{
"version": "v1",
"created": "Fri, 27 Apr 2007 15:07:04 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Yin",
"Shaoyu",
""
],
[
"Su",
"Ru-Keng",
""
]
] |
0704.3690 | Dolors Herbera | Lidia Angeleri-Hugel and Dolors Herbera | Mittag-Leffler conditions on modules | 45 pages | null | null | null | math.RA math.KT | null | We study Mittag-Leffler conditions on modules providing relative versions of
classical results by Raynaud and Gruson. We then apply our investigations to
several contexts. First of all, we give a new argument for solving the Baer
splitting problem. Moreover, we show that modules arising in cotorsion pairs
satisfy certain Mittag-Leffler conditions. In particular, this implies that
tilting modules satisfy a useful finiteness condition over their endomorphism
ring. In the final section, we focus on a special tilting cotorsion pair
related to the pure-semisimplicity conjecture.
| [
{
"version": "v1",
"created": "Fri, 27 Apr 2007 15:07:08 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Angeleri-Hugel",
"Lidia",
""
],
[
"Herbera",
"Dolors",
""
]
] |
0704.3691 | Tamara Corthals | T. Corthals, T. Van Cauteren, P. Van Craeyveld, J. Ryckebusch, and
D.G. Ireland | Electroproduction of kaons from the proton in a Regge-plus-resonance
approach | 14 pages, 7 figures; added discussion on double counting in the RPR
model; accepted for publication in Phys. Lett. B | Phys.Lett.B656:186-192,2007 | 10.1016/j.physletb.2007.09.036 | null | nucl-th | null | We present a Regge-plus-resonance (RPR) description of the p(e,e'K^+)Y
processes (Y=\Lambda,\Sigma^0) in the resonance region. The background
contributions to the RPR amplitude are constrained by the high-energy p(\gamma,
K^+)Y data. As a result, the number of free model parameters in the resonance
region is considerably reduced compared to typical effective-Lagrangian
approaches. We compare a selection of RPR model variants, originally
constructed to describe $KY$ photoproduction, with the world electroproduction
database. The electromagnetic form factors of the intermediate N^*s and
$\Delta^*s are computed in the Bonn constituent-quark model. With this input,
we find a reasonable description of the p(e,e'K^+)Y data without adding or
readjusting any parameters. It is demonstrated that the electroproduction
response functions are extremely useful for fine-tuning both the background and
resonant contributions to the reaction dynamics.
| [
{
"version": "v1",
"created": "Fri, 27 Apr 2007 15:13:03 GMT"
},
{
"version": "v2",
"created": "Tue, 25 Sep 2007 15:26:33 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Corthals",
"T.",
""
],
[
"Van Cauteren",
"T.",
""
],
[
"Van Craeyveld",
"P.",
""
],
[
"Ryckebusch",
"J.",
""
],
[
"Ireland",
"D. G.",
""
]
] |
0704.3692 | Stanislav Denisov | S. I. Denisov (1 and 2), M. Kostur (1), E. S. Denisova (2), and P.
H\"anggi (1 and 3) ((1) Universit\"at Augsburg, Germany, (2) Sumy State
University, Ukraine, (3) National University of Singapore, Republic of
Singapore) | Analytically solvable model of a driven system with quenched dichotomous
disorder | 18 pages, 5 figures | Phys. Rev. E 75, 061123 (2007) | 10.1103/PhysRevE.75.061123 | null | cond-mat.stat-mech cond-mat.dis-nn | null | We perform a time-dependent study of the driven dynamics of overdamped
particles which are placed in a one-dimensional, piecewise linear random
potential. This set-up of spatially quenched disorder then exerts a dichotomous
varying random force on the particles. We derive the path integral
representation of the resulting probability density function for the position
of the particles and transform this quantity of interest into the form of a
Fourier integral. In doing so, the evolution of the probability density can be
investigated analytically for finite times. It is demonstrated that the
probability density contains both a $\delta$-singular contribution and a
regular part. While the former part plays a dominant role at short times, the
latter rules the behavior at large evolution times. The slow approach of the
probability density to a limiting Gaussian form as time tends to infinity is
elucidated in detail.
| [
{
"version": "v1",
"created": "Fri, 27 Apr 2007 15:16:13 GMT"
},
{
"version": "v2",
"created": "Thu, 12 Jul 2007 10:13:07 GMT"
}
] | 2016-08-14T00:00:00 | [
[
"Denisov",
"S. I.",
"",
"1 and 2"
],
[
"Kostur",
"M.",
"",
"1 and 3"
],
[
"Denisova",
"E. S.",
"",
"1 and 3"
],
[
"Hänggi",
"P.",
"",
"1 and 3"
]
] |
0704.3693 | Michael Wemyss | M. Wemyss | Reconstruction Algebras of Type A | 30 pages. Easier to read, final version | null | null | null | math.AG math.RA | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We introduce a new class of algebras, called reconstruction algebras, and
present some of their basic properties. These non-commutative rings dictate in
every way the process of resolving the Cohen-Macaulay singularities C^2/G where
G is a finite small cyclic subgroup of GL(2,C).
| [
{
"version": "v1",
"created": "Fri, 27 Apr 2007 15:36:20 GMT"
},
{
"version": "v2",
"created": "Wed, 19 Sep 2007 10:42:32 GMT"
},
{
"version": "v3",
"created": "Tue, 16 Sep 2008 02:44:45 GMT"
},
{
"version": "v4",
"created": "Fri, 17 Dec 2010 15:07:58 GMT"
}
] | 2010-12-20T00:00:00 | [
[
"Wemyss",
"M.",
""
]
] |
0704.3694 | Rob Leigh | R.G. Leigh, D. Minic, A. Yelnikov | On The Spectrum of Yang-Mills Theory in 2+1 Dimensions, Analytically | conference proceedings submission for Theory Canada 2, Perimeter
Institute, Waterloo ON, June 2006 | null | 10.1139/P07-069 | null | hep-th | null | We review our recent work on the glueball spectrum of pure Yang-Mills theory
in 2+1 dimensions. The calculations make use of Karabali-Nair corner variables
in the Hamiltonian formalism, and involve a determination of the leading form
of the ground-state wavefunctional.
| [
{
"version": "v1",
"created": "Fri, 27 Apr 2007 15:20:40 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Leigh",
"R. G.",
""
],
[
"Minic",
"D.",
""
],
[
"Yelnikov",
"A.",
""
]
] |
0704.3695 | Derek Harland | Derek Harland | Large scale and large period limits of symmetric calorons | 27 pages, 2 figures. Figures, proofs, and references added; typos
corrected | J. Math. Phys. 48, 082905 (2007) | 10.1063/1.2768186 | DCPT-07/11 | hep-th | null | We construct SU(2) calorons, with non-trivial holonomy, instanton charge 2
and magnetic charge 0 or -1; these calorons have two constituent monopoles,
with charges (2,2) or (2,1). Our calorons are U(1)-symmetric and are
constructed via the Nahm transform. They fall into distinct families which can
be classified using representation theory. We consider large scale and large
period limits of these calorons; in particular, the large scale limit may be a
monopole, or a caloron with different topological charges.
| [
{
"version": "v1",
"created": "Fri, 27 Apr 2007 15:31:39 GMT"
},
{
"version": "v2",
"created": "Tue, 4 Sep 2007 14:47:46 GMT"
}
] | 2007-09-04T00:00:00 | [
[
"Harland",
"Derek",
""
]
] |
0704.3696 | Peter M Johnson | Peter M. Johnson | A weighted graph problem from commutative algebra | Withdrawn, since my later 0805.4449 contains this and much more | null | null | null | math.AC math.CO | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We give an especially simple proof of a theorem in graph theory that forms
the key part of the solution to a problem in commutative algebra, on how to
characterize the integral closure of a polynomial ring generated by quadratic
monomials.
| [
{
"version": "v1",
"created": "Fri, 27 Apr 2007 15:35:53 GMT"
},
{
"version": "v2",
"created": "Wed, 20 Jan 2010 04:51:26 GMT"
},
{
"version": "v3",
"created": "Tue, 7 Jun 2011 22:05:44 GMT"
}
] | 2011-06-09T00:00:00 | [
[
"Johnson",
"Peter M.",
""
]
] |
0704.3697 | Michael Joyce | Michael Joyce and Bruno Marcos | Quantification of discreteness effects in cosmological N-body
simulations: II. Evolution up to shell crossing | 18 pages, 10 figures, sequel to astro-ph/0410451 (on initial
conditions), final version with minor changes, to appear in Phys. Rev. D | Phys.Rev.D76:103505,2007 | 10.1103/PhysRevD.76.103505 | null | astro-ph | null | We apply a recently developed perturbative formalism which describes the
evolution under their self-gravity of particles displaced from a perfect
lattice to quantify precisely, up to shell crossing, the effects of
discreteness in dissipationless cosmological N-body simulations. We give simple
expressions, explicitly dependent on the particle density, for the evolution of
power in each mode as a function of red-shift. For typical starting red-shifts
the effect of finite particle number is to {\it slow down} slightly the growth
of power compared to that in the fluid limit (e.g. by about ten percent at half
the Nyquist frequency), and to induce also dispersion in the growth as a
function of direction at a comparable level. In the limit that the initial
red-shift tends to infinity, at fixed particle density, the evolution in fact
diverges from that in the fluid limit (described by the Zeldovich
approximation). Contrary to widely held belief, this means that a simulation
started at a red-shift much higher than the red-shift of shell crossing
actually gives a worse, rather than a better, result. We also study how these
effects are modified when there is a small-scale regularization of the
gravitational force. We show that such a smoothing may reduce the anisotropy of
the discreteness effects, but it then {\it increases} their average effect.
This behaviour illustrates the fact that the discreteness effects described
here are distinct from those usually considered in this context, due to
two-body collisions. Indeed the characteristic time for divergence from the
collisionless limit is proportional to $N^{2/3}$, rather than $N/ \log N$ in
the latter case.
| [
{
"version": "v1",
"created": "Fri, 27 Apr 2007 15:36:05 GMT"
},
{
"version": "v2",
"created": "Tue, 25 Sep 2007 08:38:13 GMT"
}
] | 2008-12-18T00:00:00 | [
[
"Joyce",
"Michael",
""
],
[
"Marcos",
"Bruno",
""
]
] |
0704.3698 | Ivan Losev | Ivan V. Losev | Demazure embeddings are smooth | 7 pages | IMRN 14(2009), 2588-2596 | null | null | math.AG math.RT | null | We prove Brion's conjecture stating that the closure of the orbit of a
self-normalizing spherical subalgebra in the corresponding Grassmanian is
smooth
| [
{
"version": "v1",
"created": "Fri, 27 Apr 2007 15:36:42 GMT"
}
] | 2010-06-03T00:00:00 | [
[
"Losev",
"Ivan V.",
""
]
] |
0704.3699 | Abdullah Vercin | B. Demircioglu and A. Vercin | Wigner functions, coherent states, one-dimensional marginal
probabilities and uncertainty structures of Landau levels | 20 pages. Submitted | null | null | null | quant-ph | null | Following an approach based on generating function method phase space
characteristics of Landau system are studied in the autonomous framework of
deformation quantization. Coherent state property of generating functions is
established and marginal probability densities along canonical coordinate lines
are derived. Well defined analogs of inner product, Cauchy-Bunyakowsy-Schwarz
inequality and state functional have been defined in phase space and they have
been used in analyzing the uncertainty structures. The general form of the
uncertainty relation for two real-valued functions is derived and uncertainty
products are computed in states described by Wigner functions. Minimum
uncertainty state property of the standard coherent states is presented and
uncertainty structures in the case of phase space generalized coherent states
are analyzed.
| [
{
"version": "v1",
"created": "Fri, 27 Apr 2007 15:40:09 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Demircioglu",
"B.",
""
],
[
"Vercin",
"A.",
""
]
] |
0704.3700 | Votyakov Evgeny | E.V. Votyakov, E. Zienicke, Yu. Kolesnikov | Constrained flow around a magnetic obstacle | accepted to JFM, 26 pages, 14 figures | JFM, vol. 610, 2008, p.131 - 156 | 10.1017/S0022112008002590 | null | physics.flu-dyn | null | Many practical applications exploit an external local magnetic field --
magnetic obstacle -- as an essential part of their constructions. Recently, it
has been demonstrated that the flow of an electrically conducting fluid
influenced by an external field can show several kinds of recirculation. The
present paper reports a 3D numerical study whose some results are compared with
an experiment about such a flow in a rectangular duct.
| [
{
"version": "v1",
"created": "Fri, 27 Apr 2007 15:45:54 GMT"
},
{
"version": "v2",
"created": "Wed, 7 May 2008 08:06:17 GMT"
}
] | 2008-09-12T00:00:00 | [
[
"Votyakov",
"E. V.",
""
],
[
"Zienicke",
"E.",
""
],
[
"Kolesnikov",
"Yu.",
""
]
] |
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