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| versions
list | update_date
timestamp[s] | authors_parsed
sequence |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
0704.2401 | Ho Nyung Lee | Ho Nyung Lee, Serge M. Nakhmanson, Matthew F. Chisholm, Hans M.
Christen, Karin M. Rabe, and David Vanderbilt | Suppressed dependence of polarization on epitaxial strain in highly
polar ferroelectrics | 4 pages, 3 figures | Phys. Rev. Lett. 98, 217602 (2007). | 10.1103/PhysRevLett.98.217602 | null | cond-mat.mtrl-sci | null | A combined experimental and computational investigation of coupling between
polarization and epitaxial strain in highly polar ferroelectric
PbZr_0.2Ti_0.8O_3 (PZT) thin films is reported. A comparison of the properties
of relaxed (tetragonality c/a = 1.05) and highly-strained (c/a = 1.09)
epitaxial films shows that polarization, while being amongst the highest
reported for PZT or PbTiO_3 in either film or bulk forms (P_r = 82
microC/cm^2), is almost independent of the epitaxial strain. We attribute this
behavior to a suppressed sensitivity of the A-site cations to epitaxial strain
in these Pb-based perovskites, where the ferroelectric displacements are
already large, contrary to the case of less polar perovskites, such as BaTiO_3.
In the latter case, the A-site cation (Ba) and equatorial oxygen displacements
can lead to substantial polarization increases.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 18:55:24 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Lee",
"Ho Nyung",
""
],
[
"Nakhmanson",
"Serge M.",
""
],
[
"Chisholm",
"Matthew F.",
""
],
[
"Christen",
"Hans M.",
""
],
[
"Rabe",
"Karin M.",
""
],
[
"Vanderbilt",
"David",
""
]
] |
0704.2402 | Francisco Ruiz del Portal | Francisco R. Ruiz del Portal, Jos\'e Manuel Salazar | Indices of the iterates of $R^3$-homeomorphisms at Lyapunov stable fixed
points | 19 pages, 8 figures | null | null | null | math.DS math.GT | null | Given any positive sequence (\{c_n\}_{n \in {\Bbb N}}), we construct
orientation preserving homeomorphisms (f:{\Bbb R}^3 \to {\Bbb R}^3) such that
(Fix(f)=Per(f)=\{0\}), (0) is Lyapunov stable and (\limsup \frac{|i(f^m,
0)|}{c_m}= \infty). We will use our results to discuss and to point out some
strong differences with respect to the computation and behavior of the
sequences of the indices of planar homeomorphisms.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 18:43:30 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"del Portal",
"Francisco R. Ruiz",
""
],
[
"Salazar",
"José Manuel",
""
]
] |
0704.2403 | Fernando Schwartz | Fernando Schwartz | Existence of outermost apparent horizons with product of spheres
topology | Replaced by revised version. Improvements in exposition and simpler
proofs. 3 figures added | Commun. Anal. Geom.16:799-817, 2008 | null | null | gr-qc hep-th math.DG | null | In this paper we find new examples of Riemannian manifolds with outermost
apparent horizons with nonspherical topology, in dimensions four and above.
More precisely, for any $n,m\ge1$, we construct asymptotically flat, scalar
flat Riemannian manifolds containing smooth outermost minimal hypersurfaces
with topology $S^n\times S^{m+1}$. In the context of general relativity these
hypersurfaces correspond to outermost apparent horizons of black holes.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 18:50:45 GMT"
},
{
"version": "v2",
"created": "Wed, 3 Oct 2007 01:48:27 GMT"
}
] | 2011-07-13T00:00:00 | [
[
"Schwartz",
"Fernando",
""
]
] |
0704.2404 | Stefano Forte | Simone Marzani, Richard D.Ball, Pietro Falgari and Stefano Forte | BFKL at Next-to-Next-to-Leading Order | 34 pages, 6 figures, TeX with harvmac. Various small typos corrects,
in particular first term in eq D.3. Final version to be published in Nucl.
Phys. B | Nucl.Phys.B783:143-175,2007 | 10.1016/j.nuclphysb.2007.05.024 | Edinburgh 2007/08, IFUM-881-FT | hep-ph | null | We determine an approximate expression for the O(alpha_s^3) contribution
chi_2 to the kernel of the BFKL equation, which includes all collinear and
anticollinear singular contributions. This is derived using recent results on
the relation between the GLAP and BFKL kernels (including running-coupling
effects to all orders) and on small-x factorization schemes. We present the
result in various schemes, relevant both for applications to the BFKL equation
and to small-x evolution of parton distributions.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 18:54:37 GMT"
},
{
"version": "v2",
"created": "Mon, 25 Jun 2007 09:37:05 GMT"
}
] | 2010-03-25T00:00:00 | [
[
"Marzani",
"Simone",
""
],
[
"Ball",
"Richard D.",
""
],
[
"Falgari",
"Pietro",
""
],
[
"Forte",
"Stefano",
""
]
] |
0704.2405 | Robert Bock | Robert D. Bock | Unimodular Relativity and the Dark Matter Problem | null | null | null | null | gr-qc astro-ph | null | We introduce a modified divergence law for the energy-momentum tensor in the
theory of unimodular relativity. Consequently, an additional equation for the
measure field follows from the divergence of the field equations. The equations
of motion are derived and the weak-field, low-velocity limit is investigated.
It is found that the gravitational acceleration acquires a term that is
proportional to the gradient of the mass density. We show that this term can
provide the additional acceleration observed on astrophysical scales without
the need for dark matter.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 18:57:19 GMT"
},
{
"version": "v2",
"created": "Thu, 20 Sep 2007 12:23:35 GMT"
}
] | 2007-09-20T00:00:00 | [
[
"Bock",
"Robert D.",
""
]
] |
0704.2406 | Robert Bock | Robert D. Bock | Dynamics of the universe in the modified unimodular theory of gravity | null | null | null | null | gr-qc astro-ph | null | The equations that govern the dynamics of the universe in the modified
unimodular theory of gravity are derived. We find a mechanism for inflation in
the early universe without postulating a false vacuum state during the first
$10^{-35}$ seconds after the Big Bang. In addition, we find a natural
explanation for the acceleration of the universe without resorting to dark
energy.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 19:03:42 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Bock",
"Robert D.",
""
]
] |
0704.2407 | Brian Punsly | Kajal K. Ghosh and Brian Punsly | The Physical Nature of Polar Broad Absorption Line Quasars | To appear in ApJ Letters | null | 10.1086/518859 | null | astro-ph | null | It has been shown based on radio variability arguments that some BALQSOs
(broad absorption line quasars) are viewed along the polar axis (orthogonal to
accretion disk) in the recent article of Zhou et al. These arguments are based
on the brightness temperature, $T_{b}$ exceeding $10^{12} ^{\circ}$ K which
leads to the well-known inverse Compton catastrophe unless the radio jet is
relativistic and is viewed along its axis. In this letter, we expand the Zhou
et al sample of polar BALQSOs to the entire SDSS DR5. In the process, we
clarify a mistake in their calculation of brightness temperature. The expanded
sample of high $T_{b}$ BALQSOS, has an inordinately large fraction of LoBALQSOs
(low ionization BALQSOs). We consider this an important clue to understanding
the nature of the polar BALQSOs. This is expected in the polar BALQSO
analytical/numerical models of Punsly in which LoBALQSOs occur when the line of
sight is very close to the polar axis, where the outflow density is the
highest.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 19:06:15 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Ghosh",
"Kajal K.",
""
],
[
"Punsly",
"Brian",
""
]
] |
0704.2408 | M. D. Reed | M.D. Reed, D.M. Terndrup, A.-Y. Zhou, C.T. Unterborn, D. An, J.R.
Eggen | Resolving the pulsations of subdwarf B stars: HS 0039+4302, HS
0444+0458, and an examination of the group properties of resolved pulsators | 32 pages, 18 figures, 7 tables. Accepted for publication in MNRAS | Mon.Not.Roy.Astron.Soc.378:1049-1063,2007 | 10.1111/j.1365-2966.2007.11839.x | null | astro-ph | null | We continue our program of single-site observations of pulsating subdwarf B
(sdB) stars and present the results of extensive time series photometry of HS
0039+4302 and HS 0444+0458. Both were observed at MDM Observatory during the
fall of 2005. We extend the number of known frequencies for HS 0039+4302 from 4
to 14 and discover one additional frequency for HS 0444+0458, bringing the
total to three. We perform standard tests to search for multiplet structure,
measure amplitude variations, and examine the frequency density to constrain
the mode degree $\ell$.
Including the two stars in this paper, 23 pulsating sdB stars have received
follow-up observations designed to decipher their pulsation spectra. It is
worth an examination of what has been detected. We compare and contrast the
frequency content in terms of richness and range and the amplitudes with
regards to variability and diversity. We use this information to examine
observational correlations with the proposed $\kappa$ pulsation mechanism as
well as alternative theories.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 19:13:10 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"Reed",
"M. D.",
""
],
[
"Terndrup",
"D. M.",
""
],
[
"Zhou",
"A. -Y.",
""
],
[
"Unterborn",
"C. T.",
""
],
[
"An",
"D.",
""
],
[
"Eggen",
"J. R.",
""
]
] |
0704.2409 | Jose Vilar | Leonor Saiz and Jose M.G. Vilar | Multilevel Deconstruction of the In Vivo Behavior of Looped DNA-Protein
Complexes | Open Access article available at
http://www.plosone.org/article/fetchArticle.action?articleURI=info%3Adoi%2F10.1371%2Fjournal.pone.0000355 | PLoS ONE 2(4): e355 (2007) | 10.1371/journal.pone.0000355 | null | q-bio.BM q-bio.SC | null | Protein-DNA complexes with loops play a fundamental role in a wide variety of
cellular processes, ranging from the regulation of DNA transcription to
telomere maintenance. As ubiquitous as they are, their precise in vivo
properties and their integration into the cellular function still remain
largely unexplored. Here, we present a multilevel approach that efficiently
connects in both directions molecular properties with cell physiology and use
it to characterize the molecular properties of the looped DNA-lac repressor
complex while functioning in vivo. The properties we uncover include the
presence of two representative conformations of the complex, the stabilization
of one conformation by DNA architectural proteins, and precise values of the
underlying twisting elastic constants and bending free energies. Incorporation
of all this molecular information into gene-regulation models reveals an
unprecedented versatility of looped DNA-protein complexes at shaping the
properties of gene expression.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 19:15:53 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Saiz",
"Leonor",
""
],
[
"Vilar",
"Jose M. G.",
""
]
] |
0704.2410 | Artem Lopatin Anatol'evich | A.A. Lopatin | The Invariant Ring of Triples of 3x3 Matrices over a Field of Arbitrary
Characteristic | 13 pages | Sibirsk. Mat. Zh 45(2004), N3, 624-633 (Russian). English
translation: Siberian Mathematical Journal 45(2004), N3, 513-521 | null | null | math.RA math.AC | null | Let R_{n,d} be the ring of invariants of d-tuples of n x n matrices under the
simultaneous conjugation action of the general linear group. A minimal
generating system and a homogeneous system of parameters for R_{3,3} are
determined. Homogeneous systems of parameters for R_{3,2}, R_{4,2} are also
pointed out.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 19:31:28 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Lopatin",
"A. A.",
""
]
] |
0704.2411 | Artem Lopatin Anatol'evich | A.A. Lopatin | Indecomposable invariants of quivers for dimension (2,...,2) and maximal
paths | 17 pages; v2. The original paper has been split into two parts. It is
the first part. | Commun. Algebra, 38 (2010), N10, 3539-3555 | null | null | math.RA math.CO | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | An upper bound on degrees of elements of a minimal generating system for
invariants of quivers of dimension (2,...,2) is established over a field of
arbitrary characteristic and its precision is estimated. The proof is based on
the reduction to the problem of description of maximal paths satisfying certain
condition.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 19:43:09 GMT"
},
{
"version": "v2",
"created": "Mon, 26 Apr 2010 17:22:14 GMT"
}
] | 2011-07-13T00:00:00 | [
[
"Lopatin",
"A. A.",
""
]
] |
0704.2412 | Donald Candela | H. Akimoto, J. S. Xia, D. Candela, W. J. Mullin, E. D. Adams, and N.
S. Sullivan | Giant viscosity enhancement in a spin-polarized Fermi liquid | 4 pages, 4 figures | null | 10.1103/PhysRevLett.99.095301 | null | cond-mat.other | null | The viscosity is measured for a Fermi liquid, a dilute $^3$He-$^4$He mixture,
under extremely high magnetic field/temperature conditions ($B \leq 14.8$ T, $T
\geq 1.5$ mK). The spin splitting energy $\mu B$ is substantially greater than
the Fermi energy $k_B T_F$; as a consequence the polarization tends to unity
and s-wave quasiparticle scattering is suppressed for $T \ll T_F$. Using a
novel composite vibrating-wire viscometer an enhancement of the viscosity is
observed by a factor of more than 500 over its low-field value. Good agreement
is found between the measured viscosity and theoretical predictions based upon
a $t$-matrix formalism.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 19:46:10 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Akimoto",
"H.",
""
],
[
"Xia",
"J. S.",
""
],
[
"Candela",
"D.",
""
],
[
"Mullin",
"W. J.",
""
],
[
"Adams",
"E. D.",
""
],
[
"Sullivan",
"N. S.",
""
]
] |
0704.2413 | Tim Bastian | T. S. Bastian, G. D. Fleishman, D. E. Gary | Radio Spectral Evolution of an X-ray Poor Impulsive Solar Flare:
Implications for Plasma Heating and Electron Acceleration | 22 pages, 10 figures | Astrophys.J.666:1256-1267,2007 | 10.1086/520106 | null | astro-ph | null | We present radio and X-ray observations of an impulsive solar flare that was
moderately intense in microwaves, yet showed very meager EUV and X-ray
emission. The flare occurred on 2001 Oct 24 and was well-observed at radio
wavelengths by the Nobeyama Radioheliograph (NoRH), the Nobeyama Radio
Polarimeters (NoRP), and by the Owens Valley Solar Array (OVSA). It was also
observed in EUV and X-ray wavelength bands by the TRACE, GOES, and Yohkoh
satellites. We find that the impulsive onset of the radio emission is
progressively delayed with increasing frequency relative to the onset of hard
X-ray emission. In contrast, the time of flux density maximum is progressively
delayed with decreasing frequency. The decay phase is independent of radio
frequency. The simple source morphology and the excellent spectral coverage at
radio wavelengths allowed us to employ a nonlinear chi-squared minimization
scheme to fit the time series of radio spectra to a source model that accounts
for the observed radio emission in terms of gyrosynchrotron radiation from
MeV-energy electrons in a relatively dense thermal plasma. We discuss plasma
heating and electron acceleration in view of the parametric trends implied by
the model fitting. We suggest that stochastic acceleration likely plays a role
in accelerating the radio-emitting electrons.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 19:47:22 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"Bastian",
"T. S.",
""
],
[
"Fleishman",
"G. D.",
""
],
[
"Gary",
"D. E.",
""
]
] |
0704.2414 | Mohamad Ali Jafarizadeh | M. A. Jafarizadeh, G. Najarbashi, Y. Akbari, H. Habibian | Multi-qubit stabilizer and cluster entanglement witnesses | 57 pages, 2 figures | null | 10.1140/epjd/e2008-00028-0 | null | quant-ph | null | One of the problems concerning entanglement witnesses (EWs) is the
construction of them by a given set of operators. Here several multi-qubit EWs
called stabilizer EWs are constructed by using the stabilizer operators of some
given multi-qubit states such as GHZ, cluster and exceptional states. The
general approach to manipulate the multi-qubit stabilizer EWs by
exact(approximate) linear programming (LP) method is described and it is shown
that the Clifford group play a crucial role in finding the hyper-planes
encircling the feasible region. The optimality, decomposability and
non-decomposability of constructed stabilizer EWs are discussed.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 19:49:35 GMT"
},
{
"version": "v2",
"created": "Mon, 1 Oct 2007 19:03:33 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Jafarizadeh",
"M. A.",
""
],
[
"Najarbashi",
"G.",
""
],
[
"Akbari",
"Y.",
""
],
[
"Habibian",
"H.",
""
]
] |
0704.2415 | P Brian Cameron | P. B. Cameron, S. R. Kulkarni (Caltech) | Near-Infrared and X-ray Observations of the Enigmatic G70.7+1.2 | 13 pages, 4 figures. Submitted to ApJL, referee's comments
incorporated | null | 10.1086/521077 | null | astro-ph | null | We present high resolution imaging of the puzzling radio and optical nebula
G70.7+1.2 with the Keck Observatory's laser guide star adaptive optics (LGS-AO)
system and the Chandra X-ray Observatory. The archival X-ray observations show
a hard (Gamma ~ 1.8), low luminosity (L_X ~ 4 x 10^31 ergs/s) point source at
the center of the nebula. Follow-up LGS-AO near-infrared imaging of the Chandra
error circle reveals a relatively bright (K' ~ 14 magnitude) counterpart. Both
its color and brightness are consistent with a heavily obscured B-star or
possibly a late-G/early-K giant. The most plausible explanation is that this
newly discovered X-ray source is a non-accreting B-star/pulsar binary powering
the radio and optical nebula. If so, the luminous Be-star discussed in the
literature seemingly embedded in the nebula is not the dominant force
responsible for shaping G70.7+1.2. Thus, we suggest that G70.7+1.2 is the
result of two unrelated objects (a B-star X-ray binary and a Be star)
interacting with a dense molecular cloud. With this explanation we believe we
have solved the mystery of the origin of G70.7+1.2.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 20:47:03 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Cameron",
"P. B.",
"",
"Caltech"
],
[
"Kulkarni",
"S. R.",
"",
"Caltech"
]
] |
0704.2416 | Niayesh Afshordi | Niayesh Afshordi (Perimeter/Harvard) | Fundamental Plane of Sunyaev-Zeldovich clusters | 5 pages, 1 figure, added an analytic derivation of the Fundametal
Plane relation (which is distinctly different from the virial relation),
submitted to ApJ | Astrophys.J. 686 (2008) 201-205 | 10.1086/591307 | null | astro-ph | null | Sunyaev-Zel'dovich (SZ) cluster surveys are considered among the most
promising methods for probing dark energy up to large redshifts. However, their
premise is hinged upon an accurate mass-observable relationship, which could be
affected by the (rather poorly understood) physics of the intracluster gas. In
this letter, using a semi-analytic model of the intracluster gas that
accommodates various theoretical uncertainties, I develop a Fundamental Plane
relationship between the observed size, thermal energy, and mass of galaxy
clusters. In particular, I find that M ~ (Y_{SZ}/R_{SZ,2})^{3/4}, where M is
the mass, Y_{SZ} is the total SZ flux or thermal energy, and R_{SZ,2} is the SZ
half-light radius of the cluster. I first show that, within this model, using
the Fundamental Plane relationship reduces the (systematic+random) errors in
mass estimates to 14%, from 22% for a simple mass-flux relationship. Since
measurement of the cluster sizes is an inevitable part of observing the SZ
clusters, the Fundamental Plane relationship can be used to reduce the error of
the cluster mass estimates by ~ 34%, improving the accuracy of the resulting
cosmological constraints without any extra cost. I then argue why our
Fundamental Plane is distinctly different from the virial relationship that one
may naively expect between the cluster parameters. Finally, I argue that while
including more details of the observed SZ profile cannot significantly improve
the accuracy of mass estimates, a better understanding of the impact of
non-gravitational heating/cooling processes on the outskirts of the
intracluster medium (apart from external calibrations) might be the best way to
reduce these errors.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 20:07:12 GMT"
},
{
"version": "v2",
"created": "Wed, 21 Nov 2007 06:46:51 GMT"
}
] | 2009-08-29T00:00:00 | [
[
"Afshordi",
"Niayesh",
"",
"Perimeter/Harvard"
]
] |
0704.2417 | Vasiliki Pavlidou | Tonia M. Venters and Vasiliki Pavlidou (KICP, U. Chicago) | The Spectral Index Distribution of EGRET Blazars: Prospects for GLAST | 11 pages, 9 figures, emulateapj; accepted for publication in ApJ | AIP Conf.Proc.921:163-168,2007; Astrophys.J.666:128-138,2007 | 10.1063/1.2757293 10.1086/519487 | null | astro-ph | null | The intrinsic distribution of spectral indices in GeV energies of
gamma-ray--loud blazars is a critical input in determining the spectral shape
of the unresolved blazar contribution to the diffuse extragalactic gamma-ray
background, as well as an important test of blazar emission theories. We
present a maximum-likelihood method of determining the intrinsic spectral index
distribution (ISID) of a population of gamma-ray emitters which accounts for
error in measurement of individual spectral indices, and we apply it to EGRET
blazars. We find that the most likely Gaussian ISID for EGRET blazars has a
mean of 2.27 and a standard deviation of 0.20. We additionally find some
indication that FSRQs and BL Lacs may have different ISIDs (with BL Lacs being
harder). We also test for spectral index hardening associated with blazar
variability for which we find no evidence. Finally, we produce simulated GLAST
spectral index datasets and perform the same analyses. With improved statistics
due to the much larger number of resolvable blazars, GLAST data will help us
determine the ISIDs with much improved accuracy. Should any difference exist
between the ISIDs of BL Lacs and FSRQs or between the ISIDs of blazars in the
quiescent and flaring states, GLAST data will be adequate to separate these
ISIDs at a significance better than 3 sigma.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 20:01:06 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"Venters",
"Tonia M.",
"",
"KICP, U. Chicago"
],
[
"Pavlidou",
"Vasiliki",
"",
"KICP, U. Chicago"
]
] |
0704.2418 | Sadegh Khochfar | S. Khochfar and J. P. Ostriker | Adding Environmental Gas Physics to the Semi-Analytic Method for Galaxy
Formation: Gravitational Heating | replaced by accepted version to ApJ, some sections have been dropped
and text has been added to others to include the referee's comments, several
typos have been corrected | null | 10.1086/587470 | null | astro-ph | null | We present results of an attempt to include more detailed gas physics
motivated from hydrodynamical simulations within semi-analytic models (SAM) of
galaxy formation, focusing on the role that environmental effects play. The
main difference to previous SAMs is that we include 'gravitational' heating of
the intra-cluster medium (ICM) by the net surplus of gravitational potential
energy released from gas that has been stripped from infalling satellites.
Gravitational heating appears to be an efficient heating source able to prevent
cooling in environments corresponding to dark matter halos more massive than
$\sim 10^{13} $M$_{\odot}$. The energy release by gravitational heating can
match that by AGN-feedback in massive galaxies and can exceed it in the most
massive ones. However, there is a fundamental difference in the way the two
processes operate. Gravitational heating becomes important at late times, when
the peak activity of AGNs is already over, and it is very mass dependent. This
mass dependency and time behaviour gives the right trend to recover down-sizing
in the star-formation rate of massive galaxies. Abridged...
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 20:14:29 GMT"
},
{
"version": "v2",
"created": "Tue, 12 Feb 2008 21:01:22 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Khochfar",
"S.",
""
],
[
"Ostriker",
"J. P.",
""
]
] |
0704.2419 | Liviu Zarbo | Liviu P. Zarbo and Branislav K. Nikolic | Spatial distribution of local currents of massless Dirac fermions in
quantum transport through graphene nanoribbons | 5 pages, 5 figures | Europhys. Lett. 80, 47001 (2007). | 10.1209/0295-5075/80/47001 | null | cond-mat.mes-hall cond-mat.dis-nn | null | We employ the formalism of bond currents, expressed in terms of the
nonequilibrium Green functions, to image the charge flow between two sites of
the honeycomb lattice of graphene ribbons of few nanometers width. In sharp
contrast to nonrelativistic electrons, current density profiles of quantum
transport at energies close to the Dirac point in clean zigzag graphene
nanoribbons (ZGNR) differs markedly from the profiles of charge density peaked
at the edges due to zero-energy localized edge states. For transport through
the lowest propagating mode induced by these edge states, edge vacancies do not
affect current density peaked in the center of ZGNR. The long-range potential
of a single impurity acts to reduce local current around it while concurrently
increasing the current density along the zigzag edge, so that ZGNR conductance
remains perfect $G=2e^2/h$.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 22:21:32 GMT"
}
] | 2007-10-18T00:00:00 | [
[
"Zarbo",
"Liviu P.",
""
],
[
"Nikolic",
"Branislav K.",
""
]
] |
0704.2420 | I. Neill Reid | I. Neill Reid (STScI), Edwin L. Turner (Princeton University),
Margaret C. Turnbull, M. Mountain, Jeff A. Valenti (STScI) | Searching for Earth analogues around the nearest stars: the disk
age-metallicity relation and the age distribution in the Solar Neighbourhood | Accepted for publication in ApJ | Astrophys.J.665:767-784,2007 | 10.1086/519001 | null | astro-ph | null | The chemical composition of Earth's atmosphere has undergone substantial
evolution over the course of its history. It is possible, even likely, that
terrestrial planets in other planetary systems have undergone similar changes;
consequently, the age distribution of nearby stars is an important
consideration in designing surveys for Earth-analogues. Valenti & Fischer
(2005) provide age and metallicity estimates for 1039 FGK dwarfs in the Solar
Neighbourhood. Using the Hipparcos catalogue as a reference to calibrate
potential biases, we have extracted volume-limited samples of nearby stars from
the Valenti-Fischer dataset. Unlike other recent investigations, our analysis
shows clear evidence for an age-metallicity relation in the local disk, albeit
with substantial dispersion at any epoch. The mean metallicity increases from
-0.3 dex at a lookback time of ~10 Gyrs to +0.15 dex at the present day.
Supplementing the Valenti-Fischer measurements with literature data to give a
complete volume-limited sample, the age distribution of nearby FGK dwarfs is
broadly consistent with a uniform star-formation rate over the history of the
Galactic disk. In striking contrast, most stars known to have planetary
companions are younger than 5 Gyrs; however, stars with planetary companions
within 0.4 AU have a significantly flatter age distribution, indicating that
those systems are stable on timescales of many Gyrs. Several of the older,
lower metallicity host stars have enhanced [alpha/Fe] ratios, implying
membership of the thick disk. If the frequency of terrestrial planets is also
correlated with stellar metallicity, then the median age of such planetary
system is likely to be ~3 Gyrs. We discuss the implications of this hypothesis
in designing searches for Earth analogues among the nearby stars.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 20:11:57 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"Reid",
"I. Neill",
"",
"STScI"
],
[
"Turner",
"Edwin L.",
"",
"Princeton University"
],
[
"Turnbull",
"Margaret C.",
"",
"STScI"
],
[
"Mountain",
"M.",
"",
"STScI"
],
[
"Valenti",
"Jeff A.",
"",
"STScI"
]
] |
0704.2421 | Martin Kunz | Luca Amendola (INAF/OAR Italy), Martin Kunz and Domenico Sapone (U.
Geneve, Switzerland) | Measuring the dark side (with weak lensing) | 19 pages, 11 figures | JCAP 0804:013,2008 | 10.1088/1475-7516/2008/04/013 | null | astro-ph | null | We introduce a convenient parametrization of dark energy models that is
general enough to include several modified gravity models and generalized forms
of dark energy. In particular we take into account the linear perturbation
growth factor, the anisotropic stress and the modified Poisson equation. We
discuss the sensitivity of large scale weak lensing surveys like the proposed
DUNE satellite to these parameters. We find that a large-scale weak-lensing
tomographic survey is able to easily distinguish the Dvali-Gabadadze-Porrati
model from LCDM and to determine the perturbation growth index to an absolute
error of 0.02-0.03.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 10:12:22 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"Amendola",
"Luca",
"",
"INAF/OAR Italy"
],
[
"Kunz",
"Martin",
"",
"U.\n Geneve, Switzerland"
],
[
"Sapone",
"Domenico",
"",
"U.\n Geneve, Switzerland"
]
] |
0704.2422 | Meredith Hughes | A. M. Hughes, D. J. Wilner, N. Calvet, P. D'Alessio, M. J. Claussen,
M. R. Hogerheijde | An Inner Hole in the Disk around TW Hydrae Resolved in 7 Millimeter Dust
Emission | 8 pages, 4 figures, accepted by ApJ | Astrophys.J.664:536-542,2007 | 10.1086/518885 | null | astro-ph | null | We present Very Large Array observations at 7 millimeters wavelength that
resolve the dust emission structure in the disk around the young star TW Hydrae
at the scale of the ~4 AU (~0.16") radius inner hole inferred from spectral
energy distribution modeling. These high resolution data confirm directly the
presence of an inner hole in the dust disk and reveal a high brightness ring
that we associate with the directly illuminated inner edge of the disk. The
clearing of the inner disk plausibly results from the dynamical effects of a
giant planet in formation. In an appendix, we develop an analytical framework
for the interpretation of visibility curves from power-law disk models with
inner holes.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 20:13:02 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"Hughes",
"A. M.",
""
],
[
"Wilner",
"D. J.",
""
],
[
"Calvet",
"N.",
""
],
[
"D'Alessio",
"P.",
""
],
[
"Claussen",
"M. J.",
""
],
[
"Hogerheijde",
"M. R.",
""
]
] |
0704.2423 | Tord Riemann | J. Gluza (U. Katowice), K. Kajda (U. Katowice), T. Riemann (DESY) | AMBRE - a Mathematica package for the construction of Mellin-Barnes
representations for Feynman integrals | 26 pages, 10 figures, 1 table, in v2 typos in Eqn. 48 and Eqn. 57
corrected; the corresponding sample files are unchanged | Comput.Phys.Commun.177:879-893,2007 | 10.1016/j.cpc.2007.07.001 | DESY 07-037, HEPTOOLS 07-009, SFB/CPP-07-14 | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The Mathematica toolkit AMBRE derives Mellin-Barnes (MB) representations for
Feynman integrals in d=4-2eps dimensions. It may be applied for tadpoles as
well as for multi-leg multi-loop scalar and tensor integrals. AMBRE uses a
loop-by-loop approach and aims at lowest dimensions of the final MB
representations. The present version of AMBRE works fine for planar Feynman
diagrams. The output may be further processed by the package MB for the
determination of its singularity structure in eps. The AMBRE package contains
various sample applications for Feynman integrals with up to six external
particles and up to four loops.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 17:39:52 GMT"
},
{
"version": "v2",
"created": "Thu, 3 Jul 2008 16:06:06 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Gluza",
"J.",
"",
"U. Katowice"
],
[
"Kajda",
"K.",
"",
"U. Katowice"
],
[
"Riemann",
"T.",
"",
"DESY"
]
] |
0704.2424 | Dionisio Bazeia | V.I. Afonso, D. Bazeia, M.A. Gonzalez Leon, L. Losano, J. Mateos
Guilarte | Orbit-based deformation procedure for two-field models | 15 pages, 14 figures; version to appear in PRD | Phys.Rev.D76:025010,2007 | 10.1103/PhysRevD.76.025010 | null | hep-th | null | We present a method for generating new deformed solutions starting from
systems of two real scalar fields for which defect solutions and orbits are
known. The procedure generalizes the approach introduced in a previous work
[Phys. Rev. D 66, 101701(R) (2002)], in which it is shown how to construct new
models altogether with its defect solutions, in terms of the original model and
solutions. As an illustration, we work out an explicit example in detail.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 20:28:21 GMT"
},
{
"version": "v2",
"created": "Mon, 23 Apr 2007 13:45:31 GMT"
},
{
"version": "v3",
"created": "Mon, 4 Jun 2007 18:53:20 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Afonso",
"V. I.",
""
],
[
"Bazeia",
"D.",
""
],
[
"Leon",
"M. A. Gonzalez",
""
],
[
"Losano",
"L.",
""
],
[
"Guilarte",
"J. Mateos",
""
]
] |
0704.2425 | Mishkatul Bhattacharya | M. Bhattacharya and P. Meystre | Trapping and Cooling a mirror to its quantum mechanical ground state | 5 pages, 1 figure | null | 10.1103/PhysRevLett.99.073601 | null | quant-ph | null | We propose a technique aimed at cooling a harmonically oscillating mirror to
its quantum mechanical ground state starting from room temperature. Our method,
which involves the two-sided irradiation of the vibrating mirror inside an
optical cavity, combines several advantages over the two-mirror arrangements
being used currently. For comparable parameters the three-mirror configuration
provides a stiffer trap for the oscillating mirror. Furthermore it prevents
bistability from limiting the use of higher laser powers for mirror trapping,
and also partially does so for mirror cooling. Lastly, it improves the
isolation of the mirror from classical noise so that its dynamics are perturbed
mostly by the vacuum fluctuations of the optical fields. These improvements are
expected to bring the task of achieving ground state occupation for the mirror
closer to completion.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 20:29:27 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Bhattacharya",
"M.",
""
],
[
"Meystre",
"P.",
""
]
] |
0704.2426 | Dimitrios Psaltis | Dimitrios Psaltis (Arizona) | Testing General Metric Theories of Gravity with Bursting Neutron Stars | 7 pages, Physical Review D, in press; corrected expression for
Eddington limit | Phys.Rev.D77:064006,2008 | 10.1103/PhysRevD.77.064006 | null | astro-ph | null | I show that several observable properties of bursting neutron stars in metric
theories of gravity can be calculated using only conservation laws, Killing
symmetries, and the Einstein equivalence principle, without requiring the
validity of the general relativistic field equations. I calculate, in
particular, the gravitational redshift of a surface atomic line, the touchdown
luminosity of a radius-expansion burst, which is believed to be equal to the
Eddington critical luminosity, and the apparent surface area of a neutron star
as measured during the cooling tails of bursts. I show that, for a general
metric theory of gravity, the apparent surface area of a neutron star depends
on the coordinate radius of the stellar surface and on its gravitational
redshift in the exact same way as in general relativity. On the other hand, the
Eddington critical luminosity depends also on an additional parameter that
measures the degree to which the general relativistic field equations are
satisfied. These results can be used in conjunction with current and future
high-energy observations of bursting neutron stars to test general relativity
in the strong-field regime.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 20:34:26 GMT"
},
{
"version": "v2",
"created": "Thu, 10 Jan 2008 04:59:28 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Psaltis",
"Dimitrios",
"",
"Arizona"
]
] |
0704.2427 | Peter Engels | P. Engels and C. Atherton | Stationary and non-stationary fluid flow of a Bose-Einstein condensate
through a penetrable barrier | 4 pages, 4 figures | null | 10.1103/PhysRevLett.99.160405 | null | cond-mat.other | null | We experimentally study the fluid flow induced by a broad, penetrable barrier
moving through an elongated dilute gaseous Bose-Einstein condensate. The
barrier is created by a laser beam swept through the condensate, and the
resulting dipole potential can be either attractive or repulsive. We examine
both cases and find regimes of stable and unstable fluid flow: At slow speeds
of the barrier, the fluid flow is stationary due to the superfluidity of the
condensate. At intermediate speeds, we observe a non-stationary regime in which
the condensate gets filled with dark solitons. At faster speeds, soliton
formation completely ceases and a remarkable absence of excitation in the
condensate is seen again.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 20:39:12 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Engels",
"P.",
""
],
[
"Atherton",
"C.",
""
]
] |
0704.2428 | Siu-Hung Ng | Siu-Hung Ng | Hopf algebras of dimension pq, II | 14pp, Latex | Journal of Algebra, 319 (2008), no. 7, 2772--2788 | 10.1016/j.jalgebra.2007.08.003 | null | math.QA math.RA | null | Let H be a Hopf algebra of dimension pq over an algebraically closed field of
characteristic zero, where p, q are odd primes with p < q < 4p+12. We prove
that H is semisimple and thus isomorphic to a group algebra, or the dual of a
group algebra.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 21:16:43 GMT"
}
] | 2012-02-14T00:00:00 | [
[
"Ng",
"Siu-Hung",
""
]
] |
0704.2429 | Lorenzo Leal | Lorenzo Leal and Jesus Pineda | The Topological Theory of the Milnor Invariant $\bar{\mu}(1,2,3)$ | 4 pages; corrected equation | Mod.Phys.Lett.A23:205-210,2008 | 10.1142/S0217732308023979 | null | hep-th | null | We study a topological Abelian gauge theory that generalizes the Abelian
Chern-Simons one, and that leads in a natural way to the Milnor's link
invariant $\bar{\mu}(1,2,3)$ when the classical action on-shell is calculated.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 20:42:20 GMT"
},
{
"version": "v2",
"created": "Mon, 23 Apr 2007 16:27:02 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Leal",
"Lorenzo",
""
],
[
"Pineda",
"Jesus",
""
]
] |
0704.2430 | Peter Capak | P. Capak, H. Aussel, M. Ajiki, H. J. McCracken, B. Mobasher, N.
Scoville, P. Shopbell, Y. Taniguchi, D. Thompson, S. Tribiano, S. Sasaki, A.
W. Blain, M. Brusa, C. Carilli, A. Comastri, C. M. Carollo, P. Cassata, J.
Colbert, R. S. Ellis, M. Elvis, M. Giavalisco, W. Green, L. Guzzo, G.
Hasinger, O. Ilbert, C. Impey, K. Jahnke, J. Kartaltepe, J-P. Kneib, J. Koda,
A. Koekemoer, Y. Komiyama, A. Leauthaud, O. Lefevre, S. Lilly, R. Massey, S.
Miyazaki, T. Murayama, T. Nagao, J. A. Peacock, A. Pickles, C. Porciani, A.
Renzini, J. Rhodes, M. Rich, M. Salvato, D. B. Sanders, C. Scarlata, D.
Schiminovich, E. Schinnerer, M. Scodeggio, K. Sheth, Y. Shioya, L. A. M.
Tasca, J. E. Taylor, L. Yan, G. Zamorani | The First Release COSMOS Optical and Near-IR Data and Catalog | 19 pages, 13 figures, 14 tables, Accepted to ApJS for COSMOS speciall
issue | Astrophys.J.Suppl.172:99-116,2007 | 10.1086/519081 | null | astro-ph | null | We present imaging data and photometry for the COSMOS survey in 15
photometric bands between 0.3um and 2.4um. These include data taken on the
Subaru 8.3m telescope, the KPNO and CTIO 4m telescopes, and the CFHT 3.6m
telescope. Special techniques are used to ensure that the relative photometric
calibration is better than 1% across the field of view. The absolute
photometric accuracy from standard star measurements is found to be 6%. The
absolute calibration is corrected using galaxy spectra, providing colors
accurate to 2% or better. Stellar and galaxy colors and counts agree well with
the expected values. Finally, as the first step in the scientific analysis of
these data we construct panchromatic number counts which confirm that both the
geometry of the universe and the galaxy population are evolving.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 19:50:30 GMT"
}
] | 2010-11-09T00:00:00 | [
[
"Capak",
"P.",
""
],
[
"Aussel",
"H.",
""
],
[
"Ajiki",
"M.",
""
],
[
"McCracken",
"H. J.",
""
],
[
"Mobasher",
"B.",
""
],
[
"Scoville",
"N.",
""
],
[
"Shopbell",
"P.",
""
],
[
"Taniguchi",
"Y.",
""
],
[
"Thompson",
"D.",
""
],
[
"Tribiano",
"S.",
""
],
[
"Sasaki",
"S.",
""
],
[
"Blain",
"A. W.",
""
],
[
"Brusa",
"M.",
""
],
[
"Carilli",
"C.",
""
],
[
"Comastri",
"A.",
""
],
[
"Carollo",
"C. M.",
""
],
[
"Cassata",
"P.",
""
],
[
"Colbert",
"J.",
""
],
[
"Ellis",
"R. S.",
""
],
[
"Elvis",
"M.",
""
],
[
"Giavalisco",
"M.",
""
],
[
"Green",
"W.",
""
],
[
"Guzzo",
"L.",
""
],
[
"Hasinger",
"G.",
""
],
[
"Ilbert",
"O.",
""
],
[
"Impey",
"C.",
""
],
[
"Jahnke",
"K.",
""
],
[
"Kartaltepe",
"J.",
""
],
[
"Kneib",
"J-P.",
""
],
[
"Koda",
"J.",
""
],
[
"Koekemoer",
"A.",
""
],
[
"Komiyama",
"Y.",
""
],
[
"Leauthaud",
"A.",
""
],
[
"Lefevre",
"O.",
""
],
[
"Lilly",
"S.",
""
],
[
"Massey",
"R.",
""
],
[
"Miyazaki",
"S.",
""
],
[
"Murayama",
"T.",
""
],
[
"Nagao",
"T.",
""
],
[
"Peacock",
"J. A.",
""
],
[
"Pickles",
"A.",
""
],
[
"Porciani",
"C.",
""
],
[
"Renzini",
"A.",
""
],
[
"Rhodes",
"J.",
""
],
[
"Rich",
"M.",
""
],
[
"Salvato",
"M.",
""
],
[
"Sanders",
"D. B.",
""
],
[
"Scarlata",
"C.",
""
],
[
"Schiminovich",
"D.",
""
],
[
"Schinnerer",
"E.",
""
],
[
"Scodeggio",
"M.",
""
],
[
"Sheth",
"K.",
""
],
[
"Shioya",
"Y.",
""
],
[
"Tasca",
"L. A. M.",
""
],
[
"Taylor",
"J. E.",
""
],
[
"Yan",
"L.",
""
],
[
"Zamorani",
"G.",
""
]
] |
0704.2431 | Parag Ghosh | Parag Ghosh and Fernando Sols | Vortex trapping in suddenly connected Bose-Josephson junctions | 4 pages, 5 figures | Phys. Rev. A 77, 033609 (2008) | 10.1103/PhysRevA.77.033609 | null | cond-mat.supr-con | null | We investigate the problem of vortex trapping in cyclically coupled
Bose-Josephson junctions. Starting with $N$ independent BECs we couple the
condensates through Josephson links and allow the system to reach a stable
circulation by adding a dissipative term in our semiclassical equations of
motion. The central question we address is what is the probability to trap a
vortex with winding number $m$. Our numerical simulations reveal that the final
distribution of winding numbers is narrower than the initial distribution of
total phases, indicating an increased probability for no-vortex configurations.
Further, the nonlinearity of the problem manifests itself in the somewhat
counter-intuitive result that it is possible to obtain a non-zero circulation
starting with zero total phase around the loop. The final width of the
distribution of winding numbers for $N$ sites scales as $\lambda N^{\alpha}$,
where $\alpha=0.47\pm 0.01$ and $\lambda <0.67$ (value predicted for the
initial distribution) indicating a shrinking of the final distribution. The
actual value of $\lambda$ is found to depend on the strength of dissipation.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 21:47:15 GMT"
}
] | 2013-05-29T00:00:00 | [
[
"Ghosh",
"Parag",
""
],
[
"Sols",
"Fernando",
""
]
] |
0704.2432 | James Storey | J. G. Storey, J. L. Tallon, G. V. M. Williams | Thermodynamic properties of Bi2Sr2CaCu2O8 calculated from the electronic
dispersion | 5 pages, 4 figures, submitted to Physical Review Letters | null | 10.1103/PhysRevB.77.052504 | null | cond-mat.supr-con | null | The electronic dispersion for Bi2Sr2CaCu2O(8+d) has been determined from
angle-resolved photoelectron spectroscopy (ARPES). From this dispersion we
calculate the entropy and superfluid density. Even with no adjustable
parameters we obtain an exceptional match with experimental data across the
entire phase diagram, thus indirectly confirming both the ARPES and
thermodynamic data. The van Hove singularity is crossed in the overdoped region
giving a distinctive linear-in-T temperature dependence in the superfluid
density there.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 21:50:37 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Storey",
"J. G.",
""
],
[
"Tallon",
"J. L.",
""
],
[
"Williams",
"G. V. M.",
""
]
] |
0704.2433 | Cesar Fosco | C. D. Fosco, G. Torroba and H. Neuberger | A simple derivation of the Overlap Dirac Operator | 9 pages, LaTeX | Phys.Lett.B650:428-431,2007 | 10.1016/j.physletb.2007.05.045 | null | hep-lat hep-th | null | We derive the vector-like four dimensional overlap Dirac operator starting
from a five dimensional Dirac action in the presence of a delta-function
space-time defect. The effective operator is obtained by first integrating out
all the fermionic modes in the fixed gauge background, and then identifying the
contribution from the localized modes as the determinant of an operator in one
dimension less. We define physically relevant degrees of freedom on the defect
by introducing an auxiliary defect-bound fermion field and integrating out the
original five dimensional bulk field.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 22:00:26 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Fosco",
"C. D.",
""
],
[
"Torroba",
"G.",
""
],
[
"Neuberger",
"H.",
""
]
] |
0704.2434 | Jose Edgar Madriz Aguilar | Jose Edgar Madriz Aguilar | Induced inflation from a 5D purely kinetic scalar field formalism on
warped product spaces | 8 pages Accepted for publication in European Physical Journal C | Eur.Phys.J.C53:133-138,2008 | 10.1140/epjc/s10052-007-0439-8 | null | gr-qc astro-ph hep-th | null | Considering a separable and purely kinetic 5D scalar field on a warped
product metric background we propose a new and more general approach for
inducing 4D scalar potentials on a 4D constant foliation of the 5D space-time.
We obtain an induced potential for a true 4D scalar field instead of a
potential for an effective 4D scalar field. In this formalism we can recover
the usual 4D inflationary formalism with a geometrically induced inflationary
potential. In addition the quantum confinement of the inflaton modes is
obtained naturally from the model for at least a class of warping factors.
Besides the 4D inflationary physics that results of this formalism is
independent of the 4D-hypersurface chosen.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 22:07:51 GMT"
},
{
"version": "v2",
"created": "Mon, 1 Oct 2007 20:14:07 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Aguilar",
"Jose Edgar Madriz",
""
]
] |
0704.2435 | Metin Gurses | Metin Gurses | Integrable Nonautonomous Nonlinear Schrodinger Equations | 4 pages | null | null | null | nlin.SI | null | We show that a recently given nonautonomous nonlinear Schrodinger equation
(NLSE) can be transformed into the autonomous NLSE.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 14:13:12 GMT"
},
{
"version": "v2",
"created": "Tue, 1 May 2007 12:21:37 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Gurses",
"Metin",
""
]
] |
0704.2436 | Arkadiusz Berlicki | A. Berlicki | Observations and Modeling of Line Asymmetries in Chromospheric Flares | In press,"Physics of Chromospheric Plasmas" (Coimbra), ASP 368, 387
(2007) | null | null | null | astro-ph | null | For many years various asymmetrical profiles of different spectral lines
emitted from solar flares have been frequently observed. These asymmetries or
line shifts are caused predominantly by vertical mass motions in flaring layers
and they provide a good diagnostics for plasma flows during solar flares. There
are many controversial results of observations and theoretical analysis of
plasma flows in solar chromospheric flares. The main difficulty is the
interpretation of line shifts or asymmetries. For many years, methods based on
bisector techniques were used but they give a reliable results only for some
specific conditions and in most cases cannot be applied. The most promising
approach is to use the non-LTE techniques applied for flaring atmosphere. The
calculation of synthetic line profiles is performed with the radiative transfer
techniques and the assumed physical conditions correspond to flaring
atmosphere. I will present an overview of different observations and
interpretations of line asymmetries in chromospheric flares. I will explain
what we have learnt about the chromospheric evaporation in the frame of
hydrodynamical models as well as reconnection models. A critical review will be
done on the classical methods used to derive Doppler-shifts for optically thick
chomospheric lines. In particular, details on the new approach for interpreting
chromospheric line asymmetries based on the non-LTE techniques will be
presented.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 22:36:08 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Berlicki",
"A.",
""
]
] |
0704.2437 | Rafael Quintero-Torres | R. Quintero-Torres, E. Vazquez-Ceron, E. Rodriguez-Rodriguez, Andreas
Stintz, and Jean-Claude Diels | Multiple quantum wells for passive ultra short laser pulse generation | 4 pages and 3 figures | phys. stat. sol, (c) 2, No. 8, 3015-3018 (2005) | null | null | physics.optics | null | Solid state lasers are demanding independent control in the gain media and
cavity loss to achieve ultra short laser pulses using passive mode-locking.
Recently, laser mode-locking is achieved with a MBE structure with multiple
quantum wells, designed to achieve two functions; Bragg mirror and changes in
absorption to control the cavity dynamics. The use of an AlGaAs/AlAs Bragg
mirror with a 15 nm GaAs saturable absorber used in a Cr:LiSAF tuneable laser
proved to be effective to produce femtosecond pulses. The use of saturable
absorbers thus far is a trial and error procedure that is changing due to the
correlation with more predictive procedures.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 23:06:40 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Quintero-Torres",
"R.",
""
],
[
"Vazquez-Ceron",
"E.",
""
],
[
"Rodriguez-Rodriguez",
"E.",
""
],
[
"Stintz",
"Andreas",
""
],
[
"Diels",
"Jean-Claude",
""
]
] |
0704.2438 | Mathew Rogers | Mathew D. Rogers | New $_5F_4$ hypergeometric transformations, three-variable Mahler
measures, and formulas for $1/\pi$ | 14 Pages | null | null | null | math.NT | null | New relations are established between families of three-variable Mahler
measures. Those identities are then expressed as transformations for the
$_5F_4$ hypergeometric function. We use these results to obtain two explicit
$_5F_4$ evaluations, and several new formulas for $1/\pi$.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 23:20:08 GMT"
},
{
"version": "v2",
"created": "Sun, 15 Jul 2007 05:07:54 GMT"
},
{
"version": "v3",
"created": "Thu, 8 Nov 2007 06:18:41 GMT"
},
{
"version": "v4",
"created": "Fri, 16 May 2008 01:51:45 GMT"
}
] | 2008-05-16T00:00:00 | [
[
"Rogers",
"Mathew D.",
""
]
] |
0704.2439 | Valeri Kotov | Valeri N. Kotov, D. X. Yao, A. H. Castro Neto, D. K. Campbell | Quantum phase transitions beyond the dilute Bose gas limit | Proceedings of SCES'07, Houston | null | null | null | cond-mat.str-el | null | We study a Heisenberg S=1/2 ring-exchange antiferromagnet which exhibits a
quantum phase transition from a spontaneously dimerized (valence bond solid)
phase to a magnetically ordered (Neel) phase. We argue that the quantum
transition is of unconventional nature; both singlet and triplet modes of high
density condense as the transition is approached from the dimer side, signaling
restoration of lattice symmetry. These features are consistent with "deconfined
quantum criticality", of which the present model is believed to be the only
example so far.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 01:46:00 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Kotov",
"Valeri N.",
""
],
[
"Yao",
"D. X.",
""
],
[
"Neto",
"A. H. Castro",
""
],
[
"Campbell",
"D. K.",
""
]
] |
0704.2440 | Albrecht Klemm | Min-xin Huang, Albrecht Klemm, Marcos Marino and Alireza Tavanfar | Black Holes and Large Order Quantum Geometry | 42 pages, 20 eps figures, small corrections | Phys.Rev.D79:066001,2009 | 10.1103/PhysRevD.79.066001 | MAD-TH-07-05, CERN-PH-TH/2007-070 | hep-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We study five-dimensional black holes obtained by compactifying M theory on
Calabi-Yau threefolds. Recent progress in solving topological string theory on
compact, one-parameter models allows us to test numerically various conjectures
about these black holes. We give convincing evidence that a microscopic
description based on Gopakumar-Vafa invariants accounts correctly for their
macroscopic entropy, and we check that highly nontrivial cancellations -which
seem necessary to resolve the so-called entropy enigma in the OSV conjecture-
do in fact occur. We also study analytically small 5d black holes obtained by
wrapping M2 branes in the fiber of K3 fibrations. By using heterotic/type II
duality we obtain exact formulae for the microscopic degeneracies in various
geometries, and we compute their asymptotic expansion for large charges.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 23:37:09 GMT"
},
{
"version": "v2",
"created": "Sat, 13 Dec 2008 19:02:04 GMT"
}
] | 2009-03-12T00:00:00 | [
[
"Huang",
"Min-xin",
""
],
[
"Klemm",
"Albrecht",
""
],
[
"Marino",
"Marcos",
""
],
[
"Tavanfar",
"Alireza",
""
]
] |
0704.2441 | Arturas Vailionis | Rene Meyer, Arturas Vailionis, and Paul. C. McIntyre | Direct Observation of Polarization vs. Thickness Relation in Ultra-Thin
Ferroelectric Films | 7 pages, 5 figures | null | null | null | cond-mat.mtrl-sci | null | A reduction of polarization in ultra-thin ferroelectric films appears to be
fundamental to ferroelectricity at the nanoscale. For the model system PbTiO3
on SrTiO3, we report observation of the polarization vs. thickness relation.
Distinct periodicity changes of ferroelectric domains obtained from x-ray
diffraction and total energy calculations reveal a linear lowering of the
polarization below a critical thickness of ~12 nm. Independent polarization and
tetragonality measurements provide insight into the fundamental relation
between polarization and tetragonality in nanoscale ferroelectrics.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 00:01:50 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Meyer",
"Rene",
""
],
[
"Vailionis",
"Arturas",
""
],
[
"McIntyre",
"Paul. C.",
""
]
] |
0704.2442 | Evgueni Nazaretski | E. Nazaretski, D. V. Pelekhov, I. Martin, M. Zalalutdinov, J. W.
Baldwin, T. Mewes, B. Houston, P. C. Hammel, and R. Movshovich | Ferromagnetic resonance force microscopy on a thin permalloy film | 9 pages, 2 figures | Appl. Phys. Lett. 90, 234105 (2007) | 10.1063/1.2747171 | null | cond-mat.mtrl-sci cond-mat.other | null | Ferromagnetic Resonance Force Microscopy (FMRFM) offers a means of performing
local ferromagnetic resonance. We have studied the evolution of the FMRFM force
spectra in a continuous 50 nm thick permalloy film as a function of probe-film
distance and performed numerical simulations of the intensity of the FMRFM
probe-film interaction force, accounting for the presence of the localized
strongly nonuniform magnetic field of the FMRFM probe magnet. Excellent
agreement between the experimental data and the simulation results provides
insight into the mechanism of FMR mode excitation in an FMRFM experiment.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 00:04:51 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Nazaretski",
"E.",
""
],
[
"Pelekhov",
"D. V.",
""
],
[
"Martin",
"I.",
""
],
[
"Zalalutdinov",
"M.",
""
],
[
"Baldwin",
"J. W.",
""
],
[
"Mewes",
"T.",
""
],
[
"Houston",
"B.",
""
],
[
"Hammel",
"P. C.",
""
],
[
"Movshovich",
"R.",
""
]
] |
0704.2443 | Akira Koyama | Akira Koyama, Takashi Odagaki, Koji Fukao | Molecular dynamics studies on spatial scale of low energy excitation in
a simple polymer system | 4 pages, 3 figure; Figure 3 replced; Abstract replced | null | null | null | cond-mat.mtrl-sci cond-mat.soft | null | A molecular dynamics simulation is performed to investigate spatial scale of
low energy excitation (LEE) in a single linear chain of united atoms. The self
part of the dynamic structure function, $S_\mathrm{S}(q,\omega)$, is obtained
in a wide range in frequency space ($\omega$) and reciprocal space ($q$). A
broad peak corresponding to the LEE is detected at $\omega/2\pi=2.5 \times
10^{11} \mathrm{s^{-1}}$ ($\equiv \omega_{\mathrm{LEE}}/2\pi$) on the contour
maps of $S_\mathrm{S}(q,\omega)$, near and below the glass transition
temperature ($T_{\mathrm{g}}$=230 K). The
$S_\mathrm{S}(q,\omega_{\mathrm{LEE}})$ is symmetric around a maximum along the
logarithm of $q$. The inverse of $q_{\mathrm{max}}$, giving the maximum
position of $S_\mathrm{S}(q,\omega_{\mathrm{LEE}})$, depends on temperature as
$2\pi/q_{\mathrm{max}}\sim T^{0.52}$ for $60 \mathrm{K}<T<T_{\mathrm{g}}$ and
$2\pi/q_{\mathrm{max}}\sim T^{0.97}$ for $T_{\mathrm{g}}<T<600 \mathrm{K}$,
which is the spatial scale of the motion corresponding to the LEE at low
temperatures. Based on a Gaussian approximation for the displacements of
monomer groups which give rise to the motion relevant to the LEE, it is found
that the number of monomers contained in a group is about 6.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 00:22:30 GMT"
},
{
"version": "v2",
"created": "Tue, 18 Mar 2008 07:03:18 GMT"
},
{
"version": "v3",
"created": "Tue, 25 Mar 2008 09:38:20 GMT"
}
] | 2008-03-25T00:00:00 | [
[
"Koyama",
"Akira",
""
],
[
"Odagaki",
"Takashi",
""
],
[
"Fukao",
"Koji",
""
]
] |
0704.2444 | Xuelei Chen | Le Zhang, Xuelei Chen, Marc Kamionkowski, Zongguo Si, Zheng Zheng | Contraints on radiative dark-matter decay from the cosmic microwave
background | replaced with version published on PRD | Phys.Rev.D76:061301,2007 | 10.1103/PhysRevD.76.061301 | null | astro-ph hep-ph hep-th | null | If dark matter decays to electromagnetically-interacting particles, it can
inject energy into the baryonic gas and thus affect the processes of
recombination and reionization. This leaves an imprint on the cosmic microwave
background (CMB): the large-scale polarization is enhanced, and the small-scale
temperature fluctuation is damped. We use the WMAP three-year data combined
with galaxy surveys to constrain radiatively decaying dark matter. Our new
limits to the dark-matter decay width are about ten times stronger than
previous limits. For dark-matter lifetimes that exceed the age of the Universe,
a limit of $\zeta \Gamma_{\chi} < 1.7 \times 10^{-25} s^{-1}$ (95% CL) is
derived, where $\zeta$ is the efficiency of converting decay energy into
ionization energy. Limits for lifetimes short compared with the age of the
Universe are also derived. We forecast improvements expected from the Planck
satellite.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 00:24:13 GMT"
},
{
"version": "v2",
"created": "Fri, 28 Sep 2007 02:15:27 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Zhang",
"Le",
""
],
[
"Chen",
"Xuelei",
""
],
[
"Kamionkowski",
"Marc",
""
],
[
"Si",
"Zongguo",
""
],
[
"Zheng",
"Zheng",
""
]
] |
0704.2445 | Valery V. Kravtsov | V. Kravtsov (1,2), G. Alcaino (3), G. Marconi (4), F. Alvarado (3)
((1) Instituto de Astronomia, UCN, Antofagasta; (2) Sternberg Astronomical
Institute, MSU, Moscow; (3) Isaac Newton Institute, Santiago; (4) European
Southern Observatory, Santiago) | Multi-Color Photometry of the Galactic Globular Cluster M75 = NGC 6864.
A New Sensitive Metallicity Indicator and the Position of the Horizontal
Branch in UV | 9 pages, 7 figures, accepted for publication in A&A | null | 10.1051/0004-6361:20066721 | null | astro-ph | null | We carry out and analyze new multi-color photometry of the Galactic globular
cluster (GC) M75 in UBVI and focus on the brighter sequences of the color-
magnitude diagram (CMD), with particular emphasis on their location in U-based
CMD. Specifically, we study the level both of the horizontal (HB) and red giant
branches (RGB) relative to the main-sequence turnoff (TO) in the U magnitude.
Along with the presented photometry of M75, we use our collection of
photometric data on GCs belonging to the metal-poor range, [Fe/H]zw<-1.1 dex,
obtained from observations with different equipment, but calibrated by standard
stars situated in the observed cluster fields. We confirm our earlier finding,
and extend it to a larger magnitude range.We demonstrate that DeltaU_{TO}^{BHB}
expressing the difference in U magnitude between the TO point and the level of
the blue HB, near its red boundary, of the metal-poor GCs observed with the
EMMI camera of the NTT/ESO telescope is about 0.4-0.5 mag smaller as compared
to GCs observed with the 100" telescope and 1.3 m Warsaw telescope of the Las
Campanas Observatory. At the same time, Delta U_{TO}^{RGB}, the difference in U
magnitude between the TO and RGB inflection (brightest) points, does not show
such an apparent dependence on the characteristics of U filters used, but it
depends on cluster metallicity. We have shown, for the first time, the
dependence of the parameter DeltaU_{TO}^{RGB} on [Fe/H] and have estimated its
analytical expression, by assuming a linear relation between the parameter and
metallicity. Its slope, Delta U_{TO}^{RGB}/Delta [Fe/H]~1.2 mag/dex, is approx.
a factor of two steeper than that of the dependence of the RGB bump position in
the V magnitude on metallicity. The asymptotic giant branch (AGB) clump and
features of the RGB luminosity function (LF) of M75 are also discussed.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 00:11:24 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Kravtsov",
"V.",
""
],
[
"Alcaino",
"G.",
""
],
[
"Marconi",
"G.",
""
],
[
"Alvarado",
"F.",
""
]
] |
0704.2446 | Igor Shparlinski | I. E. Shparlinski and J. F. Voloch | Visible Points on Curves over Finite Fields | null | null | null | null | math.NT | null | For a prime $p$ and an absolutely irreducible modulo $p$ polynomial $f(U,V)
\in \Z[U,V]$ we obtain an asymptotic formulas for the number of solutions to
the congruence $f(x,y) \equiv a \pmod p$ in positive integers $x \le X$, $y \le
Y$, with the additional condition $\gcd(x,y)=1$. Such solutions have a natural
interpretation as solutions which are visible from the origin. These formulas
are derived on average over $a$ for a fixed prime $p$, and also on average over
$p$ for a fixed integer $a$.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 00:56:48 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Shparlinski",
"I. E.",
""
],
[
"Voloch",
"J. F.",
""
]
] |
0704.2447 | Curt Cutler | Duncan A. Brown, Jeff Crowder, Curt Cutler, Ilya Mandel and Michele
Vallisneri | A Three-Stage Search for Supermassive Black Hole Binaries in LISA Data | 12 pages, 3 figures, submitted to Proceedings of GWDAW-11 (Berlin,
Dec. '06) | Class.Quant.Grav.24:S595-S606,2007 | 10.1088/0264-9381/24/19/S22 | null | gr-qc | null | Gravitational waves from the inspiral and coalescence of supermassive
black-hole (SMBH) binaries with masses ~10^6 Msun are likely to be among the
strongest sources for the Laser Interferometer Space Antenna (LISA). We
describe a three-stage data-analysis pipeline designed to search for and
measure the parameters of SMBH binaries in LISA data. The first stage uses a
time-frequency track-search method to search for inspiral signals and provide a
coarse estimate of the black-hole masses m_1, m_2 and of the coalescence time
of the binary t_c. The second stage uses a sequence of matched-filter template
banks, seeded by the first stage, to improve the measurement accuracy of the
masses and coalescence time. Finally, a Markov Chain Monte Carlo search is used
to estimate all nine physical parameters of the binary. Using results from the
second stage substantially shortens the Markov Chain burn-in time and allows us
to determine the number of SMBH-binary signals in the data before starting
parameter estimation. We demonstrate our analysis pipeline using simulated data
from the first LISA Mock Data Challenge. We discuss our plan for improving this
pipeline and the challenges that will be faced in real LISA data analysis.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 01:11:55 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Brown",
"Duncan A.",
""
],
[
"Crowder",
"Jeff",
""
],
[
"Cutler",
"Curt",
""
],
[
"Mandel",
"Ilya",
""
],
[
"Vallisneri",
"Michele",
""
]
] |
0704.2448 | Ugo Dal Lago | Patrick Baillot, Paolo Coppola and Ugo Dal Lago | Light Logics and Optimal Reduction: Completeness and Complexity | 21 pages | null | null | null | cs.LO cs.PL | null | Typing of lambda-terms in Elementary and Light Affine Logic (EAL, LAL, resp.)
has been studied for two different reasons: on the one hand the evaluation of
typed terms using LAL (EAL, resp.) proof-nets admits a guaranteed polynomial
(elementary, resp.) bound; on the other hand these terms can also be evaluated
by optimal reduction using the abstract version of Lamping's algorithm. The
first reduction is global while the second one is local and asynchronous. We
prove that for LAL (EAL, resp.) typed terms, Lamping's abstract algorithm also
admits a polynomial (elementary, resp.) bound. We also show its soundness and
completeness (for EAL and LAL with type fixpoints), by using a simple geometry
of interaction model (context semantics).
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 01:17:29 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Baillot",
"Patrick",
""
],
[
"Coppola",
"Paolo",
""
],
[
"Lago",
"Ugo Dal",
""
]
] |
0704.2449 | Takashi Saitou | Takashi Saitou | Superfield formulation of 4D, N=1 massless higher spin gauge field
theory and supermatrix model | 22 pages, no figures | JHEP0707:057,2007 | 10.1088/1126-6708/2007/07/057 | UTHEP-543 | hep-th | null | We study the relation between a supermatrix model and the free 4D, N=1
supersymmetric field theory of a massless supermultiplet with spins (3, 5/2).
In order to do this, we construct a superfield formulation of the theory. We
show that solutions of the equations of motion for the supermultiplet (3, 5/2)
satisfy the equations of motion of a supermatrix model.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 01:31:09 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Saitou",
"Takashi",
""
]
] |
0704.2450 | Vladimir Nikiforov | Bela Bollobas, Vladimir Nikiforov | An Abstract Regularity Lemma | This preliminary draft is uploaded to get some feedback. Criticisms
and suggestions are welcome | null | null | null | math.CO | null | We extend Szemeredi's Regularity Lemma (SRL) to abstract measure spaces. Our
main aim is to find general conditions under which the original proof of
Szemeredi still works. To illustrate that our approach has some merit, we
outline several applications. Some of these applications seem to be tailored to
our approach: in particular, we are not aware of any alternative proofs.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 01:34:47 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Bollobas",
"Bela",
""
],
[
"Nikiforov",
"Vladimir",
""
]
] |
0704.2451 | Masayuki Matsuzaki | Masayuki Matsuzaki (Fukuoka University of Education) | Tilting instability in negative-\gamma rotating nuclei | 8 pages, 3 figures, Prog. Theor. Phys., accepted | null | 10.1143/PTP.119.421 | null | nucl-th | null | Based on the cranking model and the random phase approximation, we point out
that the wobbling excitation on top of the s band in ^{182}Os is stable against
angular momentum tilting. This is consistent with the general trend that the
wobbling excitations in \gamma<0 rotating nuclei are more stable than those in
\gamma>0 ones found in our previous studies. In higher N isotopes known to be
\gamma soft, however, a different type of tilting instability is expected. Its
possible correspondence to the experimental data is also discussed.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 01:36:37 GMT"
},
{
"version": "v2",
"created": "Thu, 7 Feb 2008 02:16:15 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Matsuzaki",
"Masayuki",
"",
"Fukuoka University of Education"
]
] |
0704.2452 | Raman Yazdani | Raman Yazdani, Masoud Ardakani | Optimum Linear LLR Calculation for Iterative Decoding on Fading Channels | This paper will be presented in IEEE International Symposium on
Information Theory (ISIT) 2007 in Nice, France | null | 10.1109/ISIT.2007.4557204 | null | cs.IT math.IT | null | On a fading channel with no channel state information at the receiver,
calculating true log-likelihood ratios (LLR) is complicated. Existing work
assume that the power of the additive noise is known and use the expected value
of the fading gain in a linear function of the channel output to find
approximate LLRs. In this work, we first assume that the power of the additive
noise is known and we find the optimum linear approximation of LLRs in the
sense of maximum achievable transmission rate on the channel. The maximum
achievable rate under this linear LLR calculation is almost equal to the
maximum achievable rate under true LLR calculation. We also observe that this
method appears to be the optimum in the sense of bit error rate performance
too. These results are then extended to the case that the noise power is
unknown at the receiver and a performance almost identical to the case that the
noise power is perfectly known is obtained.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 02:22:52 GMT"
}
] | 2012-04-17T00:00:00 | [
[
"Yazdani",
"Raman",
""
],
[
"Ardakani",
"Masoud",
""
]
] |
0704.2453 | Florentin Smarandache | Florentin Smarandache | On Carmichael's Conjecture | 4 pages | Gamma, Year VIII, 13-14, 2/XXIV & 4-5, 3/XXV, 1986 | null | null | math.GM | null | In this article we prove that equation $\phi(x)=n$, for a fixed $n$, admits a
finite number of solutions, we find the general form of these solutions, and we
show that: if $x_0$ is a unique solution of this equation then $x_0$ is a
product of a very large number of primes (we conjecture that the number of such
primes is infinite).
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 03:05:48 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Smarandache",
"Florentin",
""
]
] |
0704.2454 | Vahid Rezania | Vahid Rezania, Jack Tuszynski, Michael Hendzel | Modeling transcription factor binding events to DNA using a random
walker/jumper representation on a 1D/2D lattice with different affinity sites | 24 pages, 9 figures | Physical Biology, 4, 256-267 (2007) | 10.1088/1478-3975/4/4/003 | null | q-bio.QM q-bio.BM | null | Surviving in a diverse environment requires corresponding organism responses.
At the cellular level, such adjustment relies on the transcription factors
(TFs) which must rapidly find their target sequences amidst a vast amount of
non-relevant sequences on DNA molecules. Whether these transcription factors
locate their target sites through a 1D or 3D pathway is still a matter of
speculation. It has been suggested that the optimum search time is when the
protein equally shares its search time between 1D and 3D diffusions. In this
paper, we study the above problem using a Monte Carlo simulation by considering
a very simple physical model. A 1D strip, representing a DNA, with a number of
low affinity sites, corresponding to non-target sites, and high affinity sites,
corresponding to target sites, is considered and later extended to a 2D strip.
We study the 1D and 3D exploration pathways, and combinations of the two modes
by considering three different types of molecules: a walker that randomly walks
along the strip with no dissociation; a jumper that represents dissociation and
then re-association of a TF with the strip at later time at a distant site; and
a hopper that is similar to the jumper but it dissociates and then
re-associates at a faster rate than the jumper. We analyze the final
probability distribution of molecules for each case and find that TFs can
locate their targets fast enough even if they spend 15% of their search time
diffusing freely in the solution. This indeed agrees with recent experimental
results obtained by Elf et al. 2007 and is in contrast with theoretical
expectation.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 03:20:02 GMT"
},
{
"version": "v2",
"created": "Thu, 9 Aug 2007 17:44:57 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Rezania",
"Vahid",
""
],
[
"Tuszynski",
"Jack",
""
],
[
"Hendzel",
"Michael",
""
]
] |
0704.2455 | John Johnson | John A. Johnson, Debra A. Fischer, Geoffrey W. Marcy, Jason T. Wright,
Peter Driscoll, R. P. Butler, Saskia Hekker, Sabine Reffert and Steven S.
Vogt | Retired A Stars and Their Companions: Exoplanets Orbiting Three
Intermediate-Mass Subgiants | 31 pages, 9 figures, 6 tables, ApJ accepted, corrected minor typos | Astrophys.J.665:785-793,2007 | 10.1086/519677 | null | astro-ph | null | We report precision Doppler measurements of three intermediate-mass subgiants
from Lick and Keck Observatories. All three stars show variability in their
radial velocities consistent with planet-mass companions in Keplerian orbits.
We find a planet with a minimum mass of 2.5 Mjup in a 351.5 day orbit around HD
192699, a planet with a minimum mass of 2.0 Mjup in a 341.1 day orbit around HD
210702, and a planet with a minimum mass of 0.61 Mjup in a 297.3 day orbit
around HD 175541. Stellar mass estimates from evolutionary models indicate that
all of these stars were formerly A-type dwarfs with masses ranging from 1.65 to
1.85 Msun. These three long-period planets would not have been detectable
during their stars' main-sequence phases due to the large rotational velocities
and stellar jitter exhibited by early-type dwarfs. There are now 9 "retired"
(evolved) A-type stars (Mstar > 1.6 Msun) with known planets. All 9 planets
orbit at distances a \geq 0.78 AU, which is significantly different than the
semimajor axis distribution of planets around lower-mass stars. We examine the
possibility that the observed lack of close-in planets is due to engulfment by
their expanding host stars, but we find that this explanation is inadequate
given the relatively small stellar radii of K giants (Rstar < 32 Rsun = 0.15
AU) and subgiants (Rstar < 7 Rsun = 0.03 AU). Instead, we conclude that planets
around intermediate-mass stars reside preferentially beyond ~0.8 AU, which may
be a reflection of different formation and migration histories of planets
around A-type stars.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 03:48:52 GMT"
},
{
"version": "v2",
"created": "Thu, 19 Apr 2007 20:26:19 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Johnson",
"John A.",
""
],
[
"Fischer",
"Debra A.",
""
],
[
"Marcy",
"Geoffrey W.",
""
],
[
"Wright",
"Jason T.",
""
],
[
"Driscoll",
"Peter",
""
],
[
"Butler",
"R. P.",
""
],
[
"Hekker",
"Saskia",
""
],
[
"Reffert",
"Sabine",
""
],
[
"Vogt",
"Steven S.",
""
]
] |
0704.2456 | Pubudu Samarasekara | P. Samarasekara | Classical Heisenberg Hamiltonian Solution of Oriented Spinel
Ferrimagnetic Thin Films | 18-pages, 4-figures, 3-tables | null | null | null | cond-mat.mes-hall | null | The classical Heisenberg Hamiltonian was solved for oriented spinel thin and
thick cubic ferrites. The dipole matrix of complicated cubic cell could be
simplified into the form of dipole Matrix of simple cubic cells. This study was
confined only to the highly oriented thin films of ferrite. The variation of
total energy of Nickel ferrite thin films with angle and number of layers was
investigated. Also the change of energy with stress induced anisotropy for
Nickel ferrite films with N=5 and 1000 has been studied. Films with the
magnetic moments ratio 1.86 can be easily oriented in 90 direction when N is
greater than 400.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 03:45:19 GMT"
}
] | 2016-11-23T00:00:00 | [
[
"Samarasekara",
"P.",
""
]
] |
0704.2457 | Howard Georgi | Howard Georgi (Harvard Univ) | Another Odd Thing About Unparticle Physics | 9 pages, 8 figures - minor wording changes and additional reference
in v2 | Phys.Lett.B650:275-278,2007 | 10.1016/j.physletb.2007.05.037 | null | hep-ph | null | The peculiar propagator of scale invariant unparticles has phases that
produce unusual patterns of interference with standard model processes. We
illustrate some of these effects in $e^+e^-\to\mu^+\mu^-$.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 03:47:36 GMT"
},
{
"version": "v2",
"created": "Mon, 21 May 2007 11:04:59 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Georgi",
"Howard",
"",
"Harvard Univ"
]
] |
0704.2458 | Lorenzo Zambotti | Luigi Ambrosio, Giuseppe Savare, Lorenzo Zambotti | Existence and Stability for Fokker-Planck equations with log-concave
reference measure | null | null | null | null | math.PR | null | We study Markov processes associated with stochastic differential equations,
whose non-linearities are gradients of convex functionals. We prove a general
result of existence of such Markov processes and a priori estimates on the
transition probabilities. The main result is the following stability property:
if the associated invariant measures converge weakly, then the Markov processes
converge in law. The proofs are based on the interpretation of a Fokker-Planck
equation as the steepest descent flow of the relative Entropy functional in the
space of probability measures, endowed with the Wasserstein distance.
Applications include stochastic partial differential equations and convergence
of equilibrium fluctuations for a class of random interfaces.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 04:03:17 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Ambrosio",
"Luigi",
""
],
[
"Savare",
"Giuseppe",
""
],
[
"Zambotti",
"Lorenzo",
""
]
] |
0704.2459 | Eleazar R. Carrasco | E.R.Carrasco (Gemini Observatory, Southern Operations Center, Chile),
E.S.Cypriano (Univesity College London, UK), G.B.Lima Neto (IAG/USP, Brazil),
H. Cuevas (Facultad de Ciencias, ULS, Chile), L. Sodre Jr. (IAG/USP, Brazil),
C. Mendes de Oliveira (IAG/USP, Brazil) and A. Ramirez (Facultad de Ciencias,
ULS, Chile) | Witnessing the formation of a galaxy cluster at z=0.485: optical and
X-ray properties of RX J1117.4+0743 ([VMF 98] 097) | 16 pages, 11 figures.emulateapj.cls style. Accepted for publication
in The Astrophysical Journal | Astrophys.J.664:777-790,2007 | 10.1086/518925 | null | astro-ph | null | We present a multiwavelength study of the poor cluster RX J1117.4+0743 ([VMF
98] 097) at z=0.485, based on GMOS/Gemini South g', r' photometry and
spectroscopy, and XMM-Newton observations. We examine its nature and
surroundings by analyzing the projected galaxy distribution, the galaxy
velocity distribution, the weak-lensing mass reconstruction, and the X-ray
spectroscopy and imaging. The cluster shows a complex morphology. It is
composed by at least two structures along the line-of-sight, with velocity
dispersions of 592+-82 km s^-1 and 391+-85 km s^-1 respectively. Other
structures are also detected in X-ray, in the galaxy projected number density
map, and by weak-lensing. One of these clumps, could be gravitationally bound
and associated to the main cluster. The derived temperature and bolometric
X-ray luminosity reveal that [VMF 98] 097 behave like a normal cluster, in
agreement with Lx-Tx correlation found for both local (z=0) and moderate
redshift (z~0.4) clusters. We find that the mass determination inferred from
weak-lensing is in average 3 to 4.8 times higher (depending on the model
assumed) than the X-ray mass. We have two possible explanations for this
discrepancy: i) the cluster is in non-equilibrium, then the deviation of the
X-ray estimated mass from the true value can be as high as a factor of two; ii)
the intervening mass along the line-of-sight of the cluster is producing an
over-estimation of the weak-lensing mass. Based on the analysis presented, we
conclude that [VMF 98] 097 is a perturbed cluster with at least two
substructures in velocity space and with other nearby structures at projected
distances of about 1 h^-1 Mpc. This cluster is an example of a poor cluster
caught in the process of accreting sub-structures to become a rich cluster.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 04:34:54 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"Carrasco",
"E. R.",
"",
"Gemini Observatory, Southern Operations Center, Chile"
],
[
"Cypriano",
"E. S.",
"",
"Univesity College London, UK"
],
[
"Neto",
"G. B. Lima",
"",
"IAG/USP, Brazil"
],
[
"Cuevas",
"H.",
"",
"Facultad de Ciencias, ULS, Chile"
],
[
"Sodre",
"L.",
"Jr.",
"IAG/USP, Brazil"
],
[
"de Oliveira",
"C. Mendes",
"",
"IAG/USP, Brazil"
],
[
"Ramirez",
"A.",
"",
"Facultad de Ciencias,\n ULS, Chile"
]
] |
0704.2460 | Sheng-Miao Wu | Sheng-Miao Wu and Ting-Gui Wang | Iron Line Profiles from Relativistic Thick Accretion Disk | 2 pages, 1 figure, Conference proceedings to appear in "The Central
Engine of Active Galactic Nuclei", ed. L. C. Ho and J.-M. Wang (San
Francisco: ASP) | null | null | null | astro-ph | null | We present a new code for calculating the Fe Kalpha line profiles from
relativistic accretion disks with finite thickness around a rotating black
hole. The thin Keplerian accretion disk must become thicker and sub-Keplerian
with increasing accretion rates. We here embark on, for the first time, a fully
relativistic computation which is aimed at gaining an insight into the effects
of geometrical thickness and the sub-Keplerian orbital velocity on the line
profiles. This code is also well-suited to produce accretion disk images.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 15:00:30 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Wu",
"Sheng-Miao",
""
],
[
"Wang",
"Ting-Gui",
""
]
] |
0704.2461 | Zakaria Meliani Z. Meliani | Z. Meliani, R. Keppens | GRB blastwaves through wind-shaped circumburst media | Accepted in A&A Letter (04/04/2007) | null | 10.1051/0004-6361:20077391 | null | astro-ph | null | Context:A significant fraction of progenitors for long gamma-ray bursts
(GRBs) are believed to be massive stars. The investigation of long GRBs
therefore requires modeling the propagation of ultra-relativistic blastwaves
through the circumburst medium surrounding massive stars. We simulate the
expansion of an isotropic, adiabatic relativistic fireball into the wind-shaped
medium around a massive GRB progenitor. The circumburst medium is composed of a
realistically stratified stellar wind zone up to its termination shock,
followed by a region of shocked wind characterized by a constant density. Aims:
We followed the evolution of the blastwave through all its stages, including
the extremely rapid acceleration up to a Lorentz factor 75 flow, its
deceleration by interaction with stellar wind, its passage of the wind
termination shock, until its propagation through shocked wind. Methods: We used
the adaptive mesh refinement versatile advection code to follow the evolution
of the fireball. Results: We show that the acceleration from purely thermal to
ultra-relativistic kinetic regimes is abrupt and produces an internally
structured blastwave. We resolved the structure of this ultra-relativistic
shell in all stages, thanks to the adaptive mesh. We comment on the dynamical
roles played by forward and reverse shock pairs in the phase of interaction
with the free stellar wind and clearly identify the complex shock-dominated
structure created when the shell crosses the terminal shock. Conclusion: We
show that in our model where the terminal shock is taken relatively close to
the massive star, the phase of self-similar deceleration of Blandford-McKee
type can only be produced in the constant density, shocked wind zone.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 04:37:44 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Meliani",
"Z.",
""
],
[
"Keppens",
"R.",
""
]
] |
0704.2462 | Y. D. Wang | Y. D. Wang, K. Semba, H. Yamaguchi | Cooling of a Micro-mechanical Resonator by the Back-action of Lorentz
Force | 10 pages, 4 figures | New J. Phys. 10 043015 (2008) | 10.1088/1367-2630/10/4/043015 | null | cond-mat.mes-hall quant-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Using a semi-classical approach, we describe an on-chip cooling protocol for
a micro-mechanical resonator by employing a superconducting flux qubit. A
Lorentz force, generated by the passive back-action of the resonator's
displacement, can cool down the thermal motion of the mechanical resonator by
applying an appropriate microwave drive to the qubit. We show that this onchip
cooling protocol, with well-controlled cooling power and a tunable response
time of passive back-action, can be highly efficient. With feasible
experimental parameters, the effective mode temperature of a resonator could be
cooled down by several orders of magnitude.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 04:42:46 GMT"
},
{
"version": "v2",
"created": "Tue, 22 May 2007 01:14:35 GMT"
},
{
"version": "v3",
"created": "Fri, 25 May 2007 01:54:54 GMT"
},
{
"version": "v4",
"created": "Mon, 19 Nov 2007 07:44:08 GMT"
},
{
"version": "v5",
"created": "Fri, 13 Feb 2009 23:34:01 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Wang",
"Y. D.",
""
],
[
"Semba",
"K.",
""
],
[
"Yamaguchi",
"H.",
""
]
] |
0704.2463 | Guenter Sigl | Oleg E. Kalashev (INR Moscow), Dmitry V. Semikoz, Guenter Sigl (APC,
Paris) | Ultra-High Energy Cosmic Rays and the GeV-TeV Diffuse Gamma-Ray Flux | 4 pages, 5 figures | Phys.Rev.D79:063005,2009 | 10.1103/PhysRevD.79.063005 | null | astro-ph hep-ph | null | Ultra-high energy cosmic ray protons accelerated in astrophysical objects
produce secondary electromagnetic cascades during propagation in the cosmic
microwave and infrared backgrounds. We show that such cascades can contribute
between ~1% and ~50% of the GeV-TeV diffuse photon flux measured by the EGRET
experiment. The GLAST satellite should have a good chance to discover this
flux.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 14:17:42 GMT"
}
] | 2014-11-18T00:00:00 | [
[
"Kalashev",
"Oleg E.",
"",
"INR Moscow"
],
[
"Semikoz",
"Dmitry V.",
"",
"APC,\n Paris"
],
[
"Sigl",
"Guenter",
"",
"APC,\n Paris"
]
] |
0704.2464 | Evgeny Feigin | B.Feigin, E.Feigin, I.Tipunin | Fermionic formulas for (1,p) logarithmic model characters in \Phi_{2,1}
quasiparticle realisation | 16 pages, reference added | null | null | null | hep-th math.QA | null | We give expressions for the characters of $(1,p)$ logarithmic conformal field
models in the Gordon-type form. The formulas are obtained in terms of
``quasiparticles'' that are Virasoro $\Phi_{2,1}$ primary fields and generalize
the symplectic fermions.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 05:34:47 GMT"
},
{
"version": "v2",
"created": "Thu, 17 May 2007 17:02:46 GMT"
},
{
"version": "v3",
"created": "Sat, 8 Sep 2007 10:04:43 GMT"
},
{
"version": "v4",
"created": "Fri, 26 Oct 2007 13:09:42 GMT"
}
] | 2011-11-09T00:00:00 | [
[
"Feigin",
"B.",
""
],
[
"Feigin",
"E.",
""
],
[
"Tipunin",
"I.",
""
]
] |
0704.2465 | Alberto T. Faraggi | Maximo Banados (Chile U., Catolica), Alberto T. Faraggi (Michigan U.),
Stefan Theisen (Potsdam, Max Planck Inst.) | N=2 supergravity in three dimensions and its Godel supersymmetric
background | null | Phys.Rev.D75:125015,2007 | 10.1103/PhysRevD.75.125015 | null | hep-th | null | The four dimensional Godel spacetime is known to have the structure M_3 x R.
It is also known that the three-dimensional factor M_3 is an exact solution of
three-dimensional gravity coupled to a Maxwell-Chern-Simons theory. We build in
this paper a N=2 supergravity extension for this action and prove that the
Godel background preserves half of all supersymmetries.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 05:42:25 GMT"
},
{
"version": "v2",
"created": "Tue, 24 Apr 2007 19:45:02 GMT"
},
{
"version": "v3",
"created": "Wed, 6 Jun 2007 04:53:42 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Banados",
"Maximo",
"",
"Chile U., Catolica"
],
[
"Faraggi",
"Alberto T.",
"",
"Michigan U."
],
[
"Theisen",
"Stefan",
"",
"Potsdam, Max Planck Inst."
]
] |
0704.2466 | Mathieu Bouville | Mathieu Bouville | Is diversity good? | 7 pages | Science and Engineering Ethics vol. 14, pp. 51-63 (2008) | 10.1007/s11948-007-9032-7 | null | physics.soc-ph | null | Prominent ethical and policy issues such as affirmative action and female
enrollment in science and engineering revolve around the idea that diversity is
good. However, even though diversity is an ambiguous concept, a precise
definition is seldom provided. We show that diversity may be construed as a
factual description, a craving for symmetry, an intrinsic good, an instrumental
good, a symptom, or a side effect. These acceptions differ vastly in their
nature and properties. The first one cannot lead to any action and the second
one is mistaken. Diversity as intrinsic good is a mere opinion, which cannot be
concretely applied; moreover, the most commonly invoked forms of diversity
(sexual and racial) are not intrinsically good. On the other hand, diversity as
instrumental good can be evaluated empirically and can give rise to policies,
but these may be very weak. Finally, symptoms and side effects are not actually
about diversity. We consider the example of female enrollment in science and
engineering, interpreting the various arguments found in the literature in
light of this polysemy.
Keywords: ethics, policy, higher education, female students, minority
students, affirmative action
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 16:03:51 GMT"
}
] | 2008-03-10T00:00:00 | [
[
"Bouville",
"Mathieu",
""
]
] |
0704.2467 | Yusuke Sasano | Yusuke Sasano | Coupled Painlev\'e III systems with affine Weyl group symmetry of types
$B_5^{(1)},D_5^{(1)}$ and $D_6^{(2)}$ | 13 pages, 5 figures | null | null | null | math.AG | null | We find and study four kinds of five-parameter family of six-dimensional
coupled Painlev\'e III systems with affine Weyl group symmetry of types
$D_5^{(1)},B_5^{(1)}$ and $D_6^{(2)}$. We show that each system is equivalent
by an explicit birational and symplectic transformation, respectively. We also
show that we characterize each system from the viewpoint of holomorphy.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 06:13:29 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Sasano",
"Yusuke",
""
]
] |
0704.2468 | Alfredo L\'opez Ortega | A. Lopez-Ortega | Dirac quasinormal modes of D-dimensional de Sitter spacetime | 19 pages | Gen.Rel.Grav.39:1011-1029,2007 | 10.1007/s10714-007-0435-1 | null | gr-qc | null | We find exact solutions to the Dirac equation in D-dimensional de Sitter
spacetime. Using these solutions we analytically calculate the de Sitter
quasinormal (QN) frequencies of the Dirac field. For the massive Dirac field
this computation is similar to that previously published for massive fields of
half-integer spin moving in four dimensions. However to calculate the QN
frequencies of the massless Dirac field we must use distinct methods in odd and
even dimensions, therefore the computation is different from that already known
for other massless fields of integer spin.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 06:18:58 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Lopez-Ortega",
"A.",
""
]
] |
0704.2469 | David Barrado y Navascues | D. Barrado y Navascues, A. Bayo, M. Morales-Calderon, N. Huelamo, J.R.
Stauffer, H. Bouy | The young, wide and very low mass visual binary LOri167 | Astronomy & Astrophysics Letters, in press | 2007A&A...468L...5B | 10.1051/0004-6361:20077258 | null | astro-ph | null | We look for wide, faint companions around members of the 5 Myr Lambda Orionis
open cluster. We used optical, near-infrared, and Spitzer/IRAC photometry. We
report the discovery of a very wide very low mass visual binary, LOri167,
formed by a brown dwarf and a planetary-mass candidate located at 5 arcsec,
which seems to belong to the cluster. We derive Teff of 2125 and 1750 K. If
they are members, comparisons with theoretical models indicate masses of 17
(20-15) Mjup and 8 (13-7) Mjup, with a projected separation of 2000 AU. Such a
binary system would be difficult to explain in most models, particularly those
where substellar objects form in the disks surrounding higher mass stars.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 06:24:17 GMT"
}
] | 2016-07-01T00:00:00 | [
[
"Navascues",
"D. Barrado y",
""
],
[
"Bayo",
"A.",
""
],
[
"Morales-Calderon",
"M.",
""
],
[
"Huelamo",
"N.",
""
],
[
"Stauffer",
"J. R.",
""
],
[
"Bouy",
"H.",
""
]
] |
0704.2470 | Nikolai Nikolov | Nikolai Nikolov, Pascal J. Thomas, Wlodzimierz Zwonek | Discontinuity of the Lempert function and the Kobayashi--Royden metric
of the spectral ball | After submitting this paper to a journal in January the authors
received a paper by G. Bharali (see arXiv:0704.1966), where some of the
problems are similar to that in our paper | Integr. Equ. Oper. Theory 61 (2008), 401-412 | null | null | math.CV | null | Some results on the discontinuity properties of the Lempert function and the
Kobayashi pseudometric in the spectral ball are given.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 06:46:19 GMT"
}
] | 2010-06-23T00:00:00 | [
[
"Nikolov",
"Nikolai",
""
],
[
"Thomas",
"Pascal J.",
""
],
[
"Zwonek",
"Wlodzimierz",
""
]
] |
0704.2471 | Rei Inoue | Rei Inoue and Tomoyuki Takenawa | Tropical spectral curves and integrable cellular automata | 22 pages | null | null | null | math-ph math.AG math.MP | null | We propose a method to study the integrable cellular automata with periodic
boundary conditions, via the tropical spectral curve and its Jacobian. We
introduce the tropical version of eigenvector map from the isolevel set to a
divisor class on the tropical hyperelliptic curve. We also provide some
conjectures related to the divisor class and the Jacobian. Finally, we apply
our method to the periodic box and ball system and clarify the
algebro-geometrical meaning of the real torus introduced for its initial value
problem.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 06:48:16 GMT"
},
{
"version": "v2",
"created": "Thu, 7 Feb 2008 05:33:03 GMT"
}
] | 2008-02-07T00:00:00 | [
[
"Inoue",
"Rei",
""
],
[
"Takenawa",
"Tomoyuki",
""
]
] |
0704.2472 | Nicolas Boulanger | Nicolas Boulanger | General solutions of the Wess-Zumino consistency condition for the Weyl
anomalies | 9 pages. RevTeX file | JHEP0707:069,2007 | 10.1088/1126-6708/2007/07/069 | null | hep-th gr-qc | null | The general solutions of the Wess-Zumino consistency condition for the
conformal (or Weyl, or trace) anomalies are derived. The solutions are
obtained, in arbitrary dimensions, by explicitly computing the cohomology of
the corresponding Becchi-Rouet-Stora-Tyutin differential in the space of
integrated local functions at ghost number unity. This provides a purely
algebraic, regularization-independent classification of the Weyl anomalies in
arbitrary dimensions. The so-called type-A anomaly is shown to satisfy a
non-trivial descent of equations, similarly to the non-Abelian chiral anomaly
in Yang-Mills theory.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 19:51:39 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Boulanger",
"Nicolas",
""
]
] |
0704.2473 | Ludmila Petrova | L.I. Petrova | Conservation laws. Generation of physical fields. Principles of field
theories | 14 pages | null | null | null | math-ph math.MP | null | In the paper the role of conservation laws in evolutionary processes, which
proceed in material systems (in material media) and lead to generation of
physical fields, is shown using skew-symmetric differential forms.
In present paper the skew-symmetric differential forms on deforming
(nondifferentiable) manifolds were used in addition to exterior forms, which
have differentiable manifolds as a basis. Such skew-symmetric forms (which were
named evolutionary ones since they possess evolutionary properties), as well as
the closed exterior forms, describe the conservation laws. But in contrast to
exterior forms, which describe conservation laws for physical fields, the
evolutionary forms correspond to conservation laws for material systems.
The evolutionary forms possess an unique peculiarity, namely, the closed
exterior forms are obtained from these forms. It is just this that enables one
to describe the process of generation of physical fields, to disclose
connection between physical fields and material systems and to resolve many
problems of existing field theories.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 07:56:36 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Petrova",
"L. I.",
""
]
] |
0704.2474 | Yi Xiao | Changjun Chen and Yi Xiao | Observation of Multiple folding Pathways of beta-hairpin Trpzip2 from
Independent Continuous Folding Trajectories | 13 pages, 8 figures | null | null | null | q-bio.BM | null | We report 10 successfully folding events of trpzip2 by molecular dynamics
simulation. It is found that the trizip2 can fold into its native state through
different zipper pathways, depending on the ways of forming hydrophobic core.
We also find a very fast non-zipper pathway. This indicates that there may be
no inconsistencies in the current pictures of beta-hairpin folding mechanisms.
These pathways occur with different probabilities. zip-out is the most probable
one. This may explain the recent experiment that the turn formation is the
rate-limiting step for beta-hairpin folding.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 07:57:32 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Chen",
"Changjun",
""
],
[
"Xiao",
"Yi",
""
]
] |
0704.2475 | Zhang Shengli | Zhang Shengli, Soung-Chang Liew, Patrick P.K. Lam | Physical Layer Network Coding | null | null | null | null | cs.IT math.IT | null | A main distinguishing feature of a wireless network compared with a wired
network is its broadcast nature, in which the signal transmitted by a node may
reach several other nodes, and a node may receive signals from several other
nodes simultaneously. Rather than a blessing, this feature is treated more as
an interference-inducing nuisance in most wireless networks today (e.g., IEEE
802.11). This paper shows that the concept of network coding can be applied at
the physical layer to turn the broadcast property into a capacity-boosting
advantage in wireless ad hoc networks. Specifically, we propose a
physical-layer network coding (PNC) scheme to coordinate transmissions among
nodes. In contrast to straightforward network coding which performs coding
arithmetic on digital bit streams after they have been received, PNC makes use
of the additive nature of simultaneously arriving electromagnetic (EM) waves
for equivalent coding operation. And in doing so, PNC can potentially achieve
100% and 50% throughput increases compared with traditional transmission and
straightforward network coding, respectively, in multi-hop networks. More
specifically, the information-theoretic capacity of PNC is almost double that
of traditional transmission in the SNR region of practical interest (higher
than 0dB). We believe this is a first paper that ventures into EM-wave-based
network coding at the physical layer and demonstrates its potential for
boosting network capacity.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 08:15:37 GMT"
}
] | 2007-07-13T00:00:00 | [
[
"Shengli",
"Zhang",
""
],
[
"Liew",
"Soung-Chang",
""
],
[
"Lam",
"Patrick P. K.",
""
]
] |
0704.2476 | Yusuke Sasano | Yusuke Sasano | Coupled Painlev\'e III systems with affine Weyl group symmetry of types
$B_4^{(1)}$, $D_4^{(1)}$ and $D_5^{(2)}$ | 13 pages, 5 figures | null | null | null | math.AG | null | We find and study four kinds of a 4-parameter family of four-dimensional
coupled Painlev\'e III systems with affine Weyl group symmetry of types
$B_4^{(1)}$, $D_4^{(1)}$ and $D_5^{(2)}$. We also show that these systems are
equivalent by an explicit birational and symplectic transformation,
respectively.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 08:32:09 GMT"
},
{
"version": "v2",
"created": "Thu, 10 May 2007 05:33:22 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Sasano",
"Yusuke",
""
]
] |
0704.2477 | Simen Kvaal Mr. | Simen Kvaal, Morten Hjorth-Jensen, Halvor Moll Nilsen | Effective interactions and large-scale diagonalization for quantum dots | 7 figures, submitted to Physical Review B Single reference error
fixed | Phys. Rev. B 76 085421 (2007) | 10.1103/PhysRevB.76.085421 | null | cond-mat.str-el nucl-th physics.comp-ph | null | The widely used large-scale diagonalization method using harmonic oscillator
basis functions (an instance of the Rayleigh-Ritz method, also called a
spectral method, configuration-interaction method, or ``exact diagonalization''
method) is systematically analyzed using results for the convergence of Hermite
function series. We apply this theory to a Hamiltonian for a one-dimensional
model of a quantum dot. The method is shown to converge slowly, and the
non-smooth character of the interaction potential is identified as the main
problem with the chosen basis, while on the other hand its important advantages
are pointed out. An effective interaction obtained by a similarity
transformation is proposed for improving the convergence of the diagonalization
scheme, and numerical experiments are performed to demonstrate the improvement.
Generalizations to more particles and dimensions are discussed.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 08:38:19 GMT"
},
{
"version": "v2",
"created": "Sun, 22 Apr 2007 12:24:33 GMT"
}
] | 2009-04-14T00:00:00 | [
[
"Kvaal",
"Simen",
""
],
[
"Hjorth-Jensen",
"Morten",
""
],
[
"Nilsen",
"Halvor Moll",
""
]
] |
0704.2478 | Yusuke Sasano | Yusuke Sasano | Coupled Painlev\'e VI systems in dimension four with affine Weyl group
symmetry of types $B_6^{(1)}$, $D_6^{(1)}$ and $D_7^{(2)}$ | 33 pages, 10 figures | null | null | null | math.AG | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We find four kinds of six-parameter family of coupled Painlev\'e VI systems
in dimension four with affine Weyl group symmetry of types $B_6^{(1)}$,
$D_6^{(1)}$ and $D_7^{(2)}$. Each system is the first example which gave
higher-order Painlev\'e equations of types $B_l^{(1)},D_l^{(1)}$ and
$D_l^{(2)}$, respectively. Each system can be expressed as a polynomial
Hamiltonian system. We show that these systems are equivalent by an explicit
birational and symplectic transformation, respectively. By giving each
holomorphy condition, we can recover each system. These symmetries, holomorphy
conditions and invariant divisors are new. We also give an explicit description
of a confluence process from the system of type $D_6^{(1)}$ to the system of
type $A_5^{(1)}$ by taking the coupling confluence process from the Painlev\'e
VI system to the Painlev\'e V system.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 08:42:49 GMT"
},
{
"version": "v2",
"created": "Mon, 21 Dec 2009 05:22:35 GMT"
}
] | 2009-12-21T00:00:00 | [
[
"Sasano",
"Yusuke",
""
]
] |
0704.2479 | Henriette Astrup Leth | H. A. Leth and L. M. Madsen and J. F. McCann | Strong-field approximation for Coulomb explosion of H_2^+ by short
intense laser pulses | 8 pages, 4 figures | null | 10.1103/PhysRevA.76.033414 | null | physics.atom-ph physics.chem-ph | null | We present a simple quantum mechanical model to describe Coulomb explosion of
H$_2^+$ by short, intense, infrared laser pulses. The model is based on the
length gauge version of the molecular strong-field approximation and is valid
for pulses shorter than 50 fs where the process of dissociation prior to
ionization is negligible. The results are compared with recent experimental
results for the proton energy spectrum [I. Ben-Itzhak et al., Phys. Rev. Lett.
95, 073002 (2005), B. D. Esry et al., Phys. Rev. Lett. 97, 013003 (2006)]. The
predictions of the model reproduce the profile of the spectrum although the
peak energy is slightly lower than the observations. For comparison, we also
present results obtained by two different tunneling models for this process.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 08:45:09 GMT"
}
] | 2009-11-23T00:00:00 | [
[
"Leth",
"H. A.",
""
],
[
"Madsen",
"L. M.",
""
],
[
"McCann",
"J. F.",
""
]
] |
0704.2480 | Marie-Bernadette Lepetit | Andrew D. J. Barnes, Thomas Baikie, Vincent Hardy (CRISMAT),
Marie-Bernadette Lepetit (CRISMAT), Antoine Maignan (CRISMAT), Nigel A.
Young, M. Grazia Francesconi | Magnetic Coupling and Long-Range Order in the Spin-Chain Sulphide
Ba2cos3 | null | jounal of material chemistry 16 (28/07/2006) 3489 | null | null | cond-mat.str-el | null | In this paper, we report on the magnetic properties of Ba2CoS3, a spin-chain
compound recently found to be the first Co2+ containing one-dimensional
sulphide to show metallic-like conductivity and negative magnetoresistance. We
carried out an in-depth experimental investigation of the local structure of
the cobalt atoms, and ab-initio calculations of the resulting electronic
configuration of Co2+. From theoretical considerations, the intra-chain
coupling was predicted to be antiferromagnetic. Experimentally, several
estimates of this magnetic coupling were derived by analysing the temperature
dependence of the magnetic susceptibility. Magnetic and heat capacity
measurements also provided evidence of a three-dimensional antiferromagnetic
ordering, a feature indicative of a noticeable inter-chain coupling in this
quasi-1D system.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 08:45:37 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Barnes",
"Andrew D. J.",
"",
"CRISMAT"
],
[
"Baikie",
"Thomas",
"",
"CRISMAT"
],
[
"Hardy",
"Vincent",
"",
"CRISMAT"
],
[
"Lepetit",
"Marie-Bernadette",
"",
"CRISMAT"
],
[
"Maignan",
"Antoine",
"",
"CRISMAT"
],
[
"Young",
"Nigel A.",
""
],
[
"Francesconi",
"M. Grazia",
""
]
] |
0704.2481 | Ralf Stephan | Ralf Stephan | Lineare Rekurrenzen, Potenzreihen und ihre erzeugenden Funktionen | 14 pages; corrected umlaut handling | null | null | null | math.HO math.CO | null | Diese kurze Einfuehrung in Theorie und Berechnung linearer Rekurrenzen
versucht, eine Luecke in der Literatur zu fuellen. Zu diesem Zweck sind viele
ausfuehrliche Beispiele angegeben.
This short introduction to theory and usage of linear recurrences tries to
fill a gap in the literature by giving many extensive examples.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 08:53:37 GMT"
},
{
"version": "v2",
"created": "Fri, 20 Apr 2007 14:16:16 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Stephan",
"Ralf",
""
]
] |
0704.2482 | Pravina Borhade | Pravina Borhade, P. Ramadevi | Effective SO Superpotential for N=1 Theory with N_f Fundamental Matter | LaTeX, 1+19 pages, To appear in Nucl.Phys.B | Nucl.Phys.B774:323-339,2007 | 10.1016/j.nuclphysb.2007.04.011 | null | hep-th | null | Motivated by the duality conjecture of Dijkgraaf and Vafa between
supersymmetric gauge theories and matrix models, we derive the effective
superpotential of N=1 supersymmetric gauge theory with gauge group SO(N_c) and
arbitrary tree level polynomial superpotential of one chiral superfield in the
adjoint representation and N_f fundamental matter multiplets. For a special
point in the classical vacuum where the gauge group is unbroken, we show that
the effective superpotential matches with that obtained from the geometric
engineering approach.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 08:59:40 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Borhade",
"Pravina",
""
],
[
"Ramadevi",
"P.",
""
]
] |
0704.2483 | Marie-Annick Guillemer | Daniel Ferrand (IRMAR) | Un module inversible associ\'e au ruban de M\"obius, et quelques autres | 32 pages | null | null | 2007-27 | math.AC | null | After attaching explicitly to the M\"obius strip an invertible module over
the ring of real polynomial functions on the real circle, we expound as
directly as possible the many faces and the main algebraic properties of
invertible modules. The goal is to make this algebraic concept accessible to a
wide mathematical audience.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 09:00:14 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Ferrand",
"Daniel",
"",
"IRMAR"
]
] |
0704.2484 | Grigory Volovik | G. E. Volovik | On Larkin-Imry-Ma State of 3He-A in Aerogel | 10 pages, 6 Figures, new JLTP style, version to be published in JLTP
(Proceedings of QFS-2007) | J. Low Temp. Phys.150:453-463, 2008 | 10.1007/s10909-007-9579-3 | null | cond-mat.dis-nn cond-mat.soft hep-ph | null | Superfluid 3He-A shares the properties of spin nematic and chiral orbital
ferromagnet. Its order parameter is characterized by two vectors d and l. This
doubly anisotropic superfluid, when it is confined in aerogel, represents the
most interesting example of a system with continuous symmetry in the presence
of random anisotropy disorder. We discuss the Larkin-Imry-Ma state, which is
characterized by the short-range orientational order of the vector l, while the
long-range orientational order is destroyed by the collective action of the
randomly oriented aerogel strings. On the other hand, sufficiently large
regular anisotropy produced either by the deformation of the aerogel or by
applied superflow suppresses the Larkin-Imry-Ma effect leading to the uniform
orientation of the vector l. This interplay of regular and random anisotropy
allows us to study many different effects.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 09:04:04 GMT"
},
{
"version": "v10",
"created": "Tue, 2 Oct 2007 12:02:47 GMT"
},
{
"version": "v2",
"created": "Wed, 9 May 2007 10:46:07 GMT"
},
{
"version": "v3",
"created": "Tue, 29 May 2007 08:59:00 GMT"
},
{
"version": "v4",
"created": "Thu, 31 May 2007 10:02:00 GMT"
},
{
"version": "v5",
"created": "Mon, 2 Jul 2007 19:53:20 GMT"
},
{
"version": "v6",
"created": "Mon, 2 Jul 2007 20:32:48 GMT"
},
{
"version": "v7",
"created": "Thu, 5 Jul 2007 12:24:41 GMT"
},
{
"version": "v8",
"created": "Sun, 8 Jul 2007 10:17:02 GMT"
},
{
"version": "v9",
"created": "Mon, 13 Aug 2007 13:48:24 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Volovik",
"G. E.",
""
]
] |
0704.2485 | Vit Nov\'ak | V. Novak, K. Olejnik, M. Cukr, L. Smrcka, Z. Remes, J. Oswald | Substrate temperature changes during MBE growth of GaMnAs | 5 pages, 5 figures Submitted to Journal of Applied Physics | J.Appl.Phys. 102, 083536 (2007) | 10.1063/1.2800798 | null | cond-mat.mtrl-sci cond-mat.other | null | Remarkably big increase of the substrate temperature during the
low-temperature MBE growth of GaMnAs layers is observed by means of band gap
spectroscopy. It is explained and simulated in terms of changes in the
absorption/emission characteristics of the growing layer. Options for the
temperature variation damping are discussed.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 09:05:59 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Novak",
"V.",
""
],
[
"Olejnik",
"K.",
""
],
[
"Cukr",
"M.",
""
],
[
"Smrcka",
"L.",
""
],
[
"Remes",
"Z.",
""
],
[
"Oswald",
"J.",
""
]
] |
0704.2486 | Patrizia Romano | D. Rizzuto (1), C. Guidorzi (1,2), P. Romano (1,2), S. Covino (2), S.
Campana (2), M. Capalbi (3), G. Chincarini (1,2), G. Cusumano (4), D. Fugazza
(2), V. Mangano (4), A. Moretti (2), M. Perri (3), G. Tagliaferri (2) ((1)
Univ.Bicocca, (2) INAF-OABrera, (3) ASI-ASDC, (4) INAF-IASF Pa) | Testing the gamma-ray burst variability/peak luminosity correlation on a
Swift homogeneous sample | Accepted for Publication in MNRAS. 10 pages, 5 figures, 3 tables | Mon.Not.Roy.Astron.Soc.379:619-628,2007 | 10.1111/j.1365-2966.2007.11880.x | null | astro-ph | null | We test the gamma-ray burst correlation between temporal variability and peak
luminosity of the $\gamma$-ray profile on a homogeneous sample of 36 Swift/BAT
GRBs with firm redshift determination. This is the first time that this
correlation can be tested on a homogeneous data sample. The correlation is
confirmed, as long as the 6 GRBs with low luminosity (<5x10^{50} erg s^{-1} in
the rest-frame 100-1000 keV energy band) are ignored. We confirm that the
considerable scatter of the correlation already known is not due to the
combination of data from different instruments with different energy bands, but
it is intrinsic to the correlation itself. Thanks to the unprecedented
sensitivity of Swift/BAT, the variability/peak luminosity correlation is tested
on low-luminosity GRBs. Our results show that these GRBs are definite outliers.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 11:49:48 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"Rizzuto",
"D.",
""
],
[
"Guidorzi",
"C.",
""
],
[
"Romano",
"P.",
""
],
[
"Covino",
"S.",
""
],
[
"Campana",
"S.",
""
],
[
"Capalbi",
"M.",
""
],
[
"Chincarini",
"G.",
""
],
[
"Cusumano",
"G.",
""
],
[
"Fugazza",
"D.",
""
],
[
"Mangano",
"V.",
""
],
[
"Moretti",
"A.",
""
],
[
"Perri",
"M.",
""
],
[
"Tagliaferri",
"G.",
""
]
] |
0704.2487 | A. Ossipov | A. Ossipov, M. Titov, C. W. J. Beenakker | Reentrance effect in a graphene n-p-n junction coupled to a
superconductor | 4 pages, 3 figures | Phys. Rev. B 75, 241401(R) (2007) | 10.1103/PhysRevB.75.241401 | null | cond-mat.mes-hall cond-mat.supr-con | null | We study the interplay of Klein tunneling (= interband tunneling) between
n-doped and p-doped regions in graphene and Andreev reflection (= electron-hole
conversion) at a superconducting electrode. The tunneling conductance of an
n-p-n junction initially increases upon lowering the temperature, while the
coherence time of the electron-hole pairs is still less than their lifetime,
but then drops back again when the coherence time exceeds the lifetime. This
reentrance effect, known from diffusive conductors and ballistic quantum dots,
provides a method to detect phase coherent Klein tunneling of electron-hole
pairs.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 09:31:49 GMT"
}
] | 2007-06-10T00:00:00 | [
[
"Ossipov",
"A.",
""
],
[
"Titov",
"M.",
""
],
[
"Beenakker",
"C. W. J.",
""
]
] |
0704.2488 | Remi Carles | Thomas Alazard (LM-Orsay), R\'emi Carles (I3M) | Supercritical geometric optics for nonlinear Schrodinger equations | 29 pages. Some typos fixed | Archive for Rational Mechanics and Analysis 194, 1 (2009) 315-347 | 10.1007/s00205-008-0176-7 | null | math.AP math-ph math.MP | null | We consider the small time semi-classical limit for nonlinear Schrodinger
equations with defocusing, smooth, nonlinearity. For a super-cubic
nonlinearity, the limiting system is not directly hyperbolic, due to the
presence of vacuum. To overcome this issue, we introduce new unknown functions,
which are defined nonlinearly in terms of the wave function itself. This
approach provides a local version of the modulated energy functional introduced
by Y.Brenier. The system we obtain is hyperbolic symmetric, and the
justification of WKB analysis follows.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 09:34:47 GMT"
},
{
"version": "v2",
"created": "Fri, 27 Apr 2007 13:06:17 GMT"
}
] | 2009-10-06T00:00:00 | [
[
"Alazard",
"Thomas",
"",
"LM-Orsay"
],
[
"Carles",
"Rémi",
"",
"I3M"
]
] |
0704.2489 | W. Woelfli | W. Woelfli and W. Baltensperger | On the change of latitude of Arctic East Siberia at the end of the
Pleistocene | 8 pages, TeX | null | null | null | physics.geo-ph | null | Mammoths lived in Arctic East Siberia. In this region there is not sufficient
sunlight over the year for the growth of the plants on which these animals
feed. Therefore the latitude of this region was lower before the end of the
Pleistocene. As the cause of this geographic pole shift, we postulate a massive
object, which moved in an extremely eccentric orbit and was hot from tidal work
and solar radiation. Evaporation produced a disk-shaped cloud of ions around
the Sun. This cloud partially shielded the solar radiation, producing the cold
and warm periods that characterize the Pleistocene. The shielding depends on
the inclination of Earth's orbit, which has a period of 100'000 years. The
cloud builds up to a density at which inelastic particle collisions induce its
collapse The resulting near-periodic time dependence resembles that of
Dansgaard-Oeschger events. During cold periods fine grained inclusions were
deposited into the ice. The Pleistocene ended when the massive object had a
close encounter with the Earth, which suffered a one per mil stretching
deformation. While the deformation relaxed to an equilibrium shape in one to
several years, the globe turned relative to the rotation axis: The North Pole
moved from Greenland to the Arctic Sea. The massive object was torn to pieces,
which evaporated.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 09:45:06 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Woelfli",
"W.",
""
],
[
"Baltensperger",
"W.",
""
]
] |
0704.2490 | Nobuhiro Uekusa | Nobuhiro Uekusa | Supersymmetry breaking by constant superpotentials and O'Raifeartaigh
model in warped space | 13 pages, sections restructured, typos corrected | Mod.Phys.Lett.A23:603-616,2008 | 10.1142/S0217732308026625 | HIP-2007-19/TH | hep-th hep-ph | null | Supersymmetry breaking together by constant boundary superpotentials and by
the O'Raifeartaigh model is studied in a warped space model. It is shown that
the contribution of constant boundary superpotentials enables the moduli of
chiral supermultiplets to be stabilized and that the vacuum at the stationary
point has zero cosmological constant in a wide region of parameters.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 09:58:32 GMT"
},
{
"version": "v2",
"created": "Tue, 29 May 2007 16:50:56 GMT"
},
{
"version": "v3",
"created": "Thu, 20 Dec 2007 15:43:14 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Uekusa",
"Nobuhiro",
""
]
] |
0704.2491 | Graziano Guerra Dr | Rinaldo M. Colombo and Graziano Guerra | On the Stability Functional for Conservation Laws | 26 pages | null | null | null | math.AP | null | This note is devoted to the explicit construction of a functional defined on
all pairs of $\L1$ functions with small total variation, which is equivalent to
the $\L1$ distance and non increasing along the trajectories of a given system
of conservation laws. Two different constructions are provided, yielding an
extension of the original stability functional by Bressan, Liu and Yang.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 09:49:31 GMT"
},
{
"version": "v2",
"created": "Tue, 4 Dec 2007 16:14:07 GMT"
}
] | 2007-12-04T00:00:00 | [
[
"Colombo",
"Rinaldo M.",
""
],
[
"Guerra",
"Graziano",
""
]
] |
0704.2492 | Alexander Goldenshluger | A. Goldenhsluger and O. Lepski | Structural adaptation via $L_p$-norm oracle inequalities | null | null | null | null | math.ST math.PR stat.TH | null | In this paper we study the problem of adaptive estimation of a multivariate
function satisfying some structural assumption. We propose a novel estimation
procedure that adapts simultaneously to unknown structure and smoothness of the
underlying function. The problem of structural adaptation is stated as the
problem of selection from a given collection of estimators. We develop a
general selection rule and establish for it global oracle inequalities under
arbitrary $\rL_p$--losses. These results are applied for adaptive estimation in
the additive multi--index model.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 09:58:27 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Goldenhsluger",
"A.",
""
],
[
"Lepski",
"O.",
""
]
] |
0704.2493 | Cai-Dian Lu | Wei Wang, Yue-Long Shen and Cai-Dian Lu (IHEP, Beijing) | The study of $B_c^- \to X(3872)\pi^-(K^-)$ Decays in the Covariant
Light-Front Approach | 14 pages, Revtex4, with 1 figure | Eur.Phys.J.C51:841-847,2007 | 10.1140/epjc/s10052-007-0334-3 | null | hep-ph | null | In the covariant light-front quark model, we calculate the form factors of
$B_c^-\to J/\psi$ and $B_c^-\to X(3872)$. Since the factorization of the
exclusive processes $B_c^- \to J/\psi\pi^-(K^-)$ and $B_c^- \to
X(3872)\pi^-(K^-)$ can be proved in the soft-collinear effective theory, we can
get the branching ratios for these decays easily from the form factors.
Taking the uncertainties into account, our results for the branching ratio of
$B_c^-\to J/\psi \pi^-(K^-)$ are consistent with the previous studies. By
identifying X(3872) as a $1^{++}$ charmonium state, we obtain ${\cal
BR}(B_c^-\to X(3872)\pi^-)=(1.7^{+0.7+0.1+0.4}_{-0.6-0.2-0.4}) \times 10^{-4}$
and ${\cal BR}(B_c^-\to X(3872)K^-)=(1.3^{+0.5+0.1+0.3}_{-0.5-0.2-0.3})\times
10^{-5}$. If assuming X(3872) as a $1^{--}$ state, the branching ratios will be
one order magnitude larger than those of $1^{++}$ state. These results can be
easily used to test the charmonium description for this mysterious meson
X(3872) at LHCb experiment.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 09:58:52 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Wang",
"Wei",
"",
"IHEP, Beijing"
],
[
"Shen",
"Yue-Long",
"",
"IHEP, Beijing"
],
[
"Lu",
"Cai-Dian",
"",
"IHEP, Beijing"
]
] |
0704.2494 | Dougal Mackey | A.D. Mackey (1), M.I. Wilkinson (2), M.B. Davies (3), G.F. Gilmore (4)
((1) University of Edinburgh, (2) University of Leicester, (3) Lund
University, (4) University of Cambridge) | The effect of stellar-mass black holes on the structural evolution of
massive star clusters | Accepted for publication in MNRAS Letters; 2 figures, 1 table | Mon.Not.Roy.Astron.Soc.Lett.379:L40-L44,2007 | 10.1111/j.1745-3933.2007.00330.x | null | astro-ph | null | We present the results of realistic N-body modelling of massive star clusters
in the Magellanic Clouds, aimed at investigating a dynamical origin for the
radius-age trend observed in these systems. We find that stellar-mass black
holes, formed in the supernova explosions of the most massive cluster stars,
can constitute a dynamically important population. If a significant number of
black holes are retained (here we assume complete retention), these objects
rapidly form a dense core where interactions are common, resulting in the
scattering of black holes into the cluster halo, and the ejection of black
holes from the cluster. These two processes heat the stellar component,
resulting in prolonged core expansion of a magnitude matching the observations.
Significant core evolution is also observed in Magellanic Cloud clusters at
early times. We find that this does not result from the action of black holes,
but can be reproduced by the effects of mass-loss due to rapid stellar
evolution in a primordially mass segregated cluster.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 10:20:52 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"Mackey",
"A. D.",
""
],
[
"Wilkinson",
"M. I.",
""
],
[
"Davies",
"M. B.",
""
],
[
"Gilmore",
"G. F.",
""
]
] |
0704.2495 | Yung-mau Nie | Yung-mau Nie | Full bandstructure calculation of second harmonic generation
susceptibility of $\alpha-LiIO_{3}$ crystal | 22 pages, 4 figures | null | null | null | physics.optics | null | The present work performs full bandstructure calculations to investigate the
structural effect and the transition mechanisms of the second harmonic
generation (SHG) susceptibility of the $\alpha-LiIO_{3}$ crystal. The anomalous
inconsistency of associated experimental data of the SHG susceptibility tensor
is elucidated to be dominated by the structural effect especially on the
topology of $O$-atoms. On the manipulation of the structural effect, the
modification of SHG susceptibility using an external pressure is simulated. The
calculations of SHG susceptibility tensor are completed at finite frequencies
and the static limit. The comparison with the experiments is also incorporated.
On the analysis of the transition mechanisms, the inter-band transition is
determined to entirely dominate the whole SHG susceptibility at the static
limit; however, the effect of the intra-band motion is revealed to be as
important as that of the inter-band transition at finite frequencies.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 10:35:51 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Nie",
"Yung-mau",
""
]
] |
0704.2496 | Mehmet Ozgur Oktel | R. O. Umucalilar, M. O. Oktel | Phase Boundary of the Boson Mott Insulator in a Rotating Optical Lattice | 5 pages,3 figures. High resolution figures available upon request | Phys. Rev. A 76, 055601 (2007) | 10.1103/PhysRevA.76.055601 | null | cond-mat.mes-hall | null | We consider the Bose-Hubbard model in a two dimensional rotating optical
lattice and investigate the consequences of the effective magnetic field
created by rotation. Using a Gutzwiller type variational wavefunction, we find
an analytical expression for the Mott insulator(MI)-Superfluid(SF) transition
boundary in terms of the maximum eigenvalue of the Hofstadter butterfly. The
dependence of phase boundary on the effective magnetic field is complex,
reflecting the self-similar properties of the single particle energy spectrum.
Finally, we argue that fractional quantum Hall phases exist close to the MI-SF
transition boundaries, including MI states with particle densities greater than
one.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 10:18:35 GMT"
}
] | 2008-04-15T00:00:00 | [
[
"Umucalilar",
"R. O.",
""
],
[
"Oktel",
"M. O.",
""
]
] |
0704.2497 | Maciej Misiorny | Maciej Misiorny and J\'ozef Barnas | Current-Induced Switching of a Single-Molecule Magnet with Arbitrary
Oriented Easy Axis | 4 pages, 3 EPS figures; typos removed | null | null | null | cond-mat.mes-hall cond-mat.mtrl-sci | null | The main objective of this work is to investigate theoretically how tilting
of an easy axis of a single-molecule magnet (SMM) from the orientation
collinear with magnetic moments of the leads affects the switching process
induced by current flowing through the system. To do this we consider a model
system that consists of a SMM embedded in the nonmagnetic barrier of a magnetic
tunnel junction. The anisotropy axis of the SMM forms an arbitrary angle with
magnetic moments of the leads (the latter ones are assumed to be collinear).
The reversal of the SMM's spin takes place due to exchange interaction between
the molecule and electrons tunneling through the barrier. The current flowing
through the system as well as the average z-component of the SMM's spin are
calculated in the second-order perturbation description (Fermi golden rule).
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 10:20:51 GMT"
},
{
"version": "v2",
"created": "Sun, 6 May 2007 20:08:00 GMT"
}
] | 2016-08-14T00:00:00 | [
[
"Misiorny",
"Maciej",
""
],
[
"Barnas",
"Józef",
""
]
] |
0704.2498 | Daniel H. Lenz | Daniel Lenz, Nicolae Strungaru | Pure Point spectrum for measure dynamical systems on locally compact
Abelian groups | 22 pages | Journal de Math\'ematiques Pures et Appliqu\'ees Volume 92, Issue
4, October 2009, Pages 323-341 | 10.1016/j.matpur.2009.05.013 | null | math-ph math.MP | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We show equivalence of pure point diffraction and pure point dynamical
spectrum for measurable dynamical systems build from locally finite measures on
locally compact Abelian groups. This generalizes all earlier results of this
type. Our approach is based on a study of almost periodicity in a Hilbert
space. It allows us to set up a perturbation theory for arbitrary equivariant
measurable perturbations.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 10:23:57 GMT"
},
{
"version": "v2",
"created": "Wed, 3 Jun 2009 12:58:22 GMT"
}
] | 2020-04-02T00:00:00 | [
[
"Lenz",
"Daniel",
""
],
[
"Strungaru",
"Nicolae",
""
]
] |
0704.2499 | Clovis Jacinto de Matos | Clovis Jacinto de Matos | Electromagnetic Dark Energy and Gravitoelectrodynamics of
Superconductors | 9 pages | null | null | null | gr-qc | null | It is shown that Beck and Mackey electromagnetic model of dark energy in
superconductors can account for the non-classical inertial properties of
superconductors, which have been conjectured by the author to explain the
Cooper pair's mass excess reported by Cabrera and Tate. A new Einstein-Planck
regime for gravitation in condensed matter is proposed as a natural scale to
host the gravitoelectrodynamic properties of superconductors.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 10:32:30 GMT"
},
{
"version": "v2",
"created": "Thu, 12 Jul 2007 14:15:19 GMT"
},
{
"version": "v3",
"created": "Fri, 3 Aug 2007 12:38:27 GMT"
},
{
"version": "v4",
"created": "Tue, 7 Aug 2007 14:19:21 GMT"
},
{
"version": "v5",
"created": "Mon, 29 Oct 2007 17:10:22 GMT"
}
] | 2007-10-29T00:00:00 | [
[
"de Matos",
"Clovis Jacinto",
""
]
] |
0704.2500 | Alexander Goldenshluger | Alexander Goldenshluger | A universal procedure for aggregating estimators | Published in at http://dx.doi.org/10.1214/00-AOS576 the Annals of
Statistics (http://www.imstat.org/aos/) by the Institute of Mathematical
Statistics (http://www.imstat.org) | Annals of Statistics 2009, Vol. 37, No. 1, 542-568 | 10.1214/00-AOS576 | IMS-AOS-AOS576 | math.ST stat.TH | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | In this paper we study the aggregation problem that can be formulated as
follows. Assume that we have a family of estimators $\mathcal{F}$ built on the
basis of available observations. The goal is to construct a new estimator whose
risk is as close as possible to that of the best estimator in the family. We
propose a general aggregation scheme that is universal in the following sense:
it applies for families of arbitrary estimators and a wide variety of models
and global risk measures. The procedure is based on comparison of empirical
estimates of certain linear functionals with estimates induced by the family
$\mathcal{F}$. We derive oracle inequalities and show that they are
unimprovable in some sense. Numerical results demonstrate good practical
behavior of the procedure.
| [
{
"version": "v1",
"created": "Thu, 19 Apr 2007 10:35:18 GMT"
},
{
"version": "v2",
"created": "Thu, 10 May 2007 08:20:37 GMT"
},
{
"version": "v3",
"created": "Wed, 4 Mar 2009 13:58:54 GMT"
}
] | 2009-03-04T00:00:00 | [
[
"Goldenshluger",
"Alexander",
""
]
] |
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