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| versions
list | update_date
timestamp[s] | authors_parsed
sequence |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
0707.2630 | Toshiya Takami | Toshiya Takami, Jun Maki, Jun'ichi Ooba, Yuuichi Inadomi, Hiroaki
Honda, Ryutaro Susukita, Koji Inoue, Taizo Kobayashi, Rie Nogita, and Mutsumi
Aoyagi | Multi-physics Extension of OpenFMO Framework | 4 pages with 11 figure files, to appear in the Proceedings of ICCMSE
2007 | AIP Conf. Proc. 963, 122-125 (2007) | 10.1063/1.2835969 | null | cs.DC physics.comp-ph | null | OpenFMO framework, an open-source software (OSS) platform for Fragment
Molecular Orbital (FMO) method, is extended to multi-physics simulations (MPS).
After reviewing the several FMO implementations on distributed computer
environments, the subsequent development planning corresponding to MPS is
presented. It is discussed which should be selected as a scientific software,
lightweight and reconfigurable form or large and self-contained form.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 05:34:08 GMT"
}
] | 2009-09-29T00:00:00 | [
[
"Takami",
"Toshiya",
""
],
[
"Maki",
"Jun",
""
],
[
"Ooba",
"Jun'ichi",
""
],
[
"Inadomi",
"Yuuichi",
""
],
[
"Honda",
"Hiroaki",
""
],
[
"Susukita",
"Ryutaro",
""
],
[
"Inoue",
"Koji",
""
],
[
"Kobayashi",
"Taizo",
""
],
[
"Nogita",
"Rie",
""
],
[
"Aoyagi",
"Mutsumi",
""
]
] |
0707.2631 | JingWu Li | Jing-Wu Li, Dong-Sheng Du | The study of $B\to J/\Psi \eta^{(\prime)}$ decays and determination of
$\eta-\eta^{\prime}$ mixing angle | 16pages,4figures | Phys.Rev.D78:074030,2008 | 10.1103/PhysRevD.78.074030 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We study $B\to J/\Psi \eta^{(\prime)}$ decays and suggest two methods to
determine the $\eta-\eta^{\prime}$ mixing angle. We calculate not only the
factorizable contribution in QCD facorization scheme but also the
nonfactorizable hard spectator corrections in pQCD approach. We get the
branching ratio of $B\to J/\Psi \eta$ which is consistent with recent
experimental data and predict the branching ratio of $B\to J/\Psi
\eta^{\prime}$ to be $7.59\times 10^{-6}$. Two methods for determining
$\eta-\eta^{\prime}$ mixing angle are suggested in this paper. For the first
method, we get the $\eta-\eta^{\prime}$ mixing angle to be about
$-13.1^{\circ}$, which is in consistency with others in the literature. The
second method depends on less parameters so can be used to determine the
$\eta-\eta^{\prime}$ mixing angle with better accuracy but needs, as an input,
the branching ratio for $B\to J/\Psi \eta^{\prime}$which should be measured in
the near future.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 04:24:33 GMT"
},
{
"version": "v2",
"created": "Thu, 19 Jul 2007 06:40:37 GMT"
},
{
"version": "v3",
"created": "Wed, 8 Apr 2009 11:04:31 GMT"
}
] | 2016-09-08T00:00:00 | [
[
"Li",
"Jing-Wu",
""
],
[
"Du",
"Dong-Sheng",
""
]
] |
0707.2632 | Chee Wei Wong | Yun-Feng Xiao, Jie Gao, Xu-Bo Zou, James F. McMillan, Xiaodong Yang,
You-Ling Chen, Zheng-Fu Han, Guang-Can Guo, and Chee Wei Wong | Coupled quantum electrodynamics in photonic crystal nanocavities | 5 pages, 4 figures | null | null | null | quant-ph | null | We show that a scalable photonic crystal nanocavity array, in which single
embedded quantum dots are coherently interacting, can perform as an universal
single-operation quantum gate. In a passive system, the optical analogue of
electromagnetically-induced-transparency is observed. The presence of a single
two-level system in the array dramatically controls the spectral lineshapes.
When each cavity couples with a two-level system, our scheme achieves two-qubit
gate operations with high fidelity and low photon loss, even in the bad cavity
limit and with non-ideal detuning and decoherence.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 04:32:34 GMT"
},
{
"version": "v2",
"created": "Wed, 31 Oct 2007 04:02:34 GMT"
}
] | 2007-10-31T00:00:00 | [
[
"Xiao",
"Yun-Feng",
""
],
[
"Gao",
"Jie",
""
],
[
"Zou",
"Xu-Bo",
""
],
[
"McMillan",
"James F.",
""
],
[
"Yang",
"Xiaodong",
""
],
[
"Chen",
"You-Ling",
""
],
[
"Han",
"Zheng-Fu",
""
],
[
"Guo",
"Guang-Can",
""
],
[
"Wong",
"Chee Wei",
""
]
] |
0707.2633 | Eleftherios Gkioulekas | Eleftherios Gkioulekas | Winterberg's conjectured breaking of the superluminal quantum
correlations over large distances | 7 pages, submitted to Int. J. Theor. Phys | E. Gkioulekas (2008): Int. J. Theor. Phys. 47, 1195-1205 | 10.1007/s10773-007-9550-8 | null | quant-ph | null | We elaborate further on a hypothesis by Winterberg that turbulent
fluctuations of the zero point field may lead to a breakdown of the
superluminal quantum correlations over very large distances. A phenomenological
model that was proposed by Winterberg to estimate the transition scale of the
conjectured breakdown, does not lead to a distance that is large enough to be
agreeable with recent experiments. We consider, but rule out, the possibility
of a steeper slope in the energy spectrum of the turbulent fluctuations, due to
compressibility, as a possible mechanism that may lead to an increased
lower-bound for the transition scale. Instead, we argue that Winterberg
overestimated the intensity of the ZPF turbulent fluctuations. We calculate a
very generous corrected lower bound for the transition distance which is
consistent with current experiments.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 04:36:58 GMT"
}
] | 2010-11-16T00:00:00 | [
[
"Gkioulekas",
"Eleftherios",
""
]
] |
0707.2634 | Nabyendu Das | Nabyendu Das and Suresh G. Mishra | Fluctuations and Criticality in Quantum Paraelectrics | 9 pages, 3 figures, Published version | J. Phys.: Condens. Matter 21 (2009) 095901 | 10.1088/0953-8984/21/9/095901 | null | cond-mat.mtrl-sci cond-mat.stat-mech | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The temperature dependence of static dielectric susceptibility of a system
with strongly coupled fluctuating dipoles is calculated within a self
consistent mean fluctuation field approximation. Results are qualitatively in
good agreement with, a quantum paraelectric, SrTiO$_3$ in the low temperature
regime. We identify this system as a {\it gaped quantum paraelectric} and
suggest a possible experimental realization of a {\it quantum critical
paraelectric} through the application of hydrostatic pressure or doping by
impurity.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 04:59:04 GMT"
},
{
"version": "v2",
"created": "Fri, 20 Jul 2007 05:46:45 GMT"
},
{
"version": "v3",
"created": "Tue, 27 May 2008 13:07:14 GMT"
},
{
"version": "v4",
"created": "Wed, 30 Jul 2008 06:43:04 GMT"
},
{
"version": "v5",
"created": "Tue, 20 Jan 2009 04:38:49 GMT"
},
{
"version": "v6",
"created": "Thu, 5 Feb 2009 05:04:29 GMT"
}
] | 2015-05-13T00:00:00 | [
[
"Das",
"Nabyendu",
""
],
[
"Mishra",
"Suresh G.",
""
]
] |
0707.2635 | Madhukar Mishra Mr. | M. Mishra and C. P. Singh | Freeze-out volume of hot dense fireball | 10 pages, 2 figures | Phys.Lett.B651:119-123,2007 | 10.1016/j.physletb.2007.06.014 | null | hep-ph | null | A thermodynamically consistent excluded volume model is proposed to account
for the particle multiplicities obtained from lowest SIS energies to the
highest RHIC energies. The chemical freeze-out volumes lying in a slice of one
unit of rapidity for pions and kaons are separately inferred from this analysis
and the results are compared with the corresponding thermal freeze-out volumes
obtained from the Hanbury-Brown Twiss (HBT) pion interferometry. Furthermore,
we extract the variations of freeze-out number densities for pions and nucleons
with the center-of-mass energy in our model and compare them with the HBT data.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 05:05:20 GMT"
},
{
"version": "v2",
"created": "Fri, 20 Jul 2007 15:01:56 GMT"
},
{
"version": "v3",
"created": "Thu, 27 Sep 2007 08:18:33 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Mishra",
"M.",
""
],
[
"Singh",
"C. P.",
""
]
] |
0707.2636 | Lucian Crosthwaite | Lucian Crosthwaite and Jean Turner | CO(1-0), CO(2-1) and Neutral Gas in NGC 6946: Molecular Gas in a
Late-Type, Gas Rich, Spiral Galaxy | null | null | 10.1086/521645 | null | astro-ph | null | We present "On The Fly" maps of the CO(1-0) and CO(2-1) emission covering a
10' X 10' region of the NGC 6946. Using our CO maps and archival VLA HI
observations we create a total gas surface density map, Sigma_gas, for NGC
6946. The predominantly molecular inner gas disk transitions smoothly into an
atomic outer gas disk, with equivalent atomic and molecular gas surface
densities at R = 3.5' (6 kpc). We estimate that the total H2 mass is 3 X 10^9
Mo, roughly 1/3 of the interstellar hydrogen gas mass, and about 2% of the
dynamical mass of the galaxy at our assumed distance of 6 Mpc. The value of the
CO(2-1)/CO(1-0) line ratio ranges from 0.35 to 2; 50% of the map is covered by
very high ratio, >1, gas. The very high ratios are predominantly from interarm
regions and appear to indicate the presence of wide-spread optically thin gas.
Star formation tracers are better correlated with the total neutral gas disk
than with the molecular gas by itself implying SFR is proportional to
Sigma_gas. Using the 100 FIR and 21 cm continuum from NGC 6946 as star
formation tracers, we arrive at a gas consumption timescale of 2.8 Gyr, which
is relatively uniform across the disk. The high star formation rate at the
nucleus appears to be due to a large accumulation of molecular gas rather than
a large increase in the star formation efficiency. The mid-plane gas pressure
in the outer (R > 10 kpc) HI arms of NGC 6946 is close to the value at the
radial limit (10 kpc) of our observed CO disk. If the mid-plane gas pressure is
a factor for the formation of molecular clouds, these outer HI gas arms should
contain molecular gas which we do not see because they are beyond our detection
limit.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 05:20:21 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Crosthwaite",
"Lucian",
""
],
[
"Turner",
"Jean",
""
]
] |
0707.2637 | Youngman Kim | Youngman Kim, Chang-Hwan Lee and Ho-Ung Yee | Holographic Nuclear Matter in AdS/QCD | 16 pages, 3 figures, two references are added, typo corrected,
section 3.3 removed | Phys.Rev.D77:085030,2008 | 10.1103/PhysRevD.77.085030 | null | hep-ph hep-th nucl-th | null | We study the physics with finite nuclear density in the framework of AdS/QCD
with holographic baryon field included. Based on a mean field type approach, we
introduce the nucleon density as a bi-fermion condensate of the lowest mode of
the baryon field and calculate the density dependence of the chiral condensate
and the nucleon mass. We observe that the chiral condensate as well as the mass
of nucleon decrease with increasing nuclear density. We also consider the mass
splitting of charged vector mesons in iso-spin asymmetric nuclear matter.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 05:21:26 GMT"
},
{
"version": "v2",
"created": "Thu, 26 Jul 2007 04:49:56 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Kim",
"Youngman",
""
],
[
"Lee",
"Chang-Hwan",
""
],
[
"Yee",
"Ho-Ung",
""
]
] |
0707.2638 | Yamamoto Tokonatsu | T.Yamamoto (for the Pierre Auger Collaboration) | The UHECR spectrum measured at the Pierre Auger Observatory and its
astrophysical implications | Contribution to the 30th International Cosmic Ray Conference, Merida
Mexico, July 2007 | null | null | null | astro-ph | null | The Southern part of the Pierre Auger Observatory is nearing completion, and
has been in stable operation since January 2004 while it has grown in size. The
large sample of data collected so far has led to a significant improvement in
the measurement of the energy spectrum of UHE cosmic rays over that previously
reported by the Pierre Auger Observatory, both in statistics and in systematic
uncertainties. We summarize two measurements of the energy spectrum, one based
on the high-statistics surface detector data, and the other of the hybrid data,
where the precision of the fluorescence measurements is enhanced by additional
information from the surface array. The complementarity of the two approaches
is emphasized and results are compared. Possible astrophysical implications of
our measurements, and in particular the presence of spectral features, are
discussed.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 05:25:03 GMT"
},
{
"version": "v2",
"created": "Mon, 30 Jul 2007 02:46:14 GMT"
},
{
"version": "v3",
"created": "Mon, 13 Aug 2007 03:33:45 GMT"
}
] | 2019-08-13T00:00:00 | [
[
"Yamamoto",
"T.",
"",
"for the Pierre Auger Collaboration"
]
] |
0707.2639 | Tao Mei | T. Mei | On the vierbein formalism of general relativity | 29 pages, no figure. The previous three versions and fifth version of
this paper has been withdrawn by the author due to some unclear discussion
and errors | Gen.Rel.Grav.40:1913-1945,2008 | 10.1007/s10714-008-0613-9 | null | gr-qc | null | Both the Einstein-Hilbert action and the Einstein equations are discussed
under the absolute vierbein formalism. Taking advantage of this form, we prove
that the "kinetic energy" term, i.e., the quadratic term of time derivative
term, in the Lagrangian of the Einstein-Hilbert action is non-positive
definitive. And then, we present two groups of coordinate conditions that lead
to positive definitive kinetic energy term in the Lagrangian, as well as the
corresponding actions with positive definitive kinetic energy term,
respectively. Based on the ADM decomposition, the Hamiltonian representation
and canonical quantization of general relativity taking advantage of the
actions with positive definitive kinetic energy term are discussed; especially,
the Hamiltonian constraints with positive definitive kinetic energy term are
given, respectively. Finally, we present a group of gauge conditions such that
there is not any second time derivative term in the ten Einstein equations.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 05:30:26 GMT"
},
{
"version": "v2",
"created": "Sun, 22 Jul 2007 12:06:17 GMT"
},
{
"version": "v3",
"created": "Thu, 26 Jul 2007 07:01:40 GMT"
},
{
"version": "v4",
"created": "Tue, 23 Oct 2007 09:29:19 GMT"
},
{
"version": "v5",
"created": "Fri, 26 Oct 2007 02:54:58 GMT"
},
{
"version": "v6",
"created": "Thu, 8 Nov 2007 10:08:55 GMT"
},
{
"version": "v7",
"created": "Thu, 6 Dec 2007 00:59:01 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Mei",
"T.",
""
]
] |
0707.2640 | Minho Choi | Minho Choi | Observations of B335 in the Millimeter Continuum and the 226 GHz H2CO
Line | null | null | 10.1093/pasj/59.5.L41 | null | astro-ph | null | The protostar B335 was observed in the 1.3 mm continuum and in the H2CO 312 -
211 line with an angular resolution of about 8 arcsec. The mass of the inner
envelope detected by the dust continuum emission is about 0.02 Msun. The H2CO
spectrum at the protostellar position shows a blue-skewed double peak profile,
suggesting that the kinematics of the inner envelope is dominated by infall
motion. When the blueshifted and the redshifted peaks were imaged separately,
however, there is a small east-west displacement between the maximum positions.
This displacement suggests that some part of the H2CO emission might come from
the outflowing gas. A combined effect of the infalling envelope and the outflow
on the radiative transfer is discussed. This effect can make the line profile
asymmetry severer than what is expected from infall-only models.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 05:43:04 GMT"
}
] | 2015-05-13T00:00:00 | [
[
"Choi",
"Minho",
""
]
] |
0707.2641 | Madhukar Mishra Mr. | M. Mishra, C. P. Singh, V. J. Menon and Ritesh Kumar Dubey | $J/\psi$ suppression in Au+Au collisions at RHIC : colour screening
scenario in the bag model at variable participant numbers | 13 pages, 2 figures | Phys.Lett.B656:45-50,2007 | 10.1016/j.physletb.2007.09.043 | null | hep-ph | null | We have modified the colour screening theory of Chu and Matsui by properly
incorporating bag model equation of state for quark gluon plasma (QGP). We have
also chosen the pressure parametrization rather than parametrizing energy
density in the transverse plane. We assume that the QGP dense medium is
expanding in the longitudinal direction obeying Bjorken boost invariant scaling
law. Sequential melting of $\chi_c$, $\psi^{'}$ and $J/\psi$ is also considered
in this scenario. We have applied above formulation to the recent PHENIX
experimental data of $J/\psi$ suppression in Au + Au collisions at RHIC. We
find that the model gives a good description of data at mid-rapidity in terms
of survival probability versus number of participants without any necessity of
implementing (3+1)-dimensional expansion of the deconfined medium.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 06:04:33 GMT"
},
{
"version": "v2",
"created": "Tue, 18 Sep 2007 12:06:38 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Mishra",
"M.",
""
],
[
"Singh",
"C. P.",
""
],
[
"Menon",
"V. J.",
""
],
[
"Dubey",
"Ritesh Kumar",
""
]
] |
0707.2642 | Bruno Eckhardt | Bjorn Hof, Jerry Westerweel, Tobias M. Schneider and Bruno Eckhardt | Comment on 'Critical behaviour in the relaminarization of localized
turbulence in pipe flow' | 1 page, 2 figures | null | null | null | physics.flu-dyn | null | This is a comment on arXiv:physics/0608292, subsequently published in Phys
Rev Lett, 98, 014501 (2007), in which Willis and Kerswell study in direct
numerical simulations the statistics of turbulent lifetimes in pipe flow. They
suggest that their data for six different Reynolds numbers support a divergence
of the lifetime near a Reynolds number of about 1870. However, their conclusion
is not compelling: a re-analysis of their data shows that it is also compatible
with an exponentially increasing lifetime.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 06:27:11 GMT"
}
] | 2007-07-19T00:00:00 | [
[
"Hof",
"Bjorn",
""
],
[
"Westerweel",
"Jerry",
""
],
[
"Schneider",
"Tobias M.",
""
],
[
"Eckhardt",
"Bruno",
""
]
] |
0707.2643 | Stanley J. Brodsky | Stanley J. Brodsky | Novel QCD Phenomena | Invited talk presented at the Workshop on High PT Physics at the LHC
(LHC07), Jyvaskyla, Finland, 23-27 March 2007; typos corrected; added
reference;resolution of figures improved | PoS LHC07:002,2007 | null | SLAC-PUB-12632 | hep-ph | null | I discuss a number of novel topics in QCD, including the use of the AdS/CFT
correspondence between Anti-de Sitter space and conformal gauge theories to
obtain an analytically tractable approximation to QCD in the regime where the
QCD coupling is large and constant. In particular, there is an exact
correspondence between the fifth-dimension coordinate z of AdS space and a
specific impact variable zeta which measures the separation of the quark
constituents within the hadron in ordinary space-time. This connection allows
one to compute the analytic form of the frame-independent light-front
wavefunctions of mesons and baryons, the fundamental entities which encode
hadron properties and allow the computation of exclusive scattering amplitudes.
I also discuss a number of novel phenomenological features of QCD. Initial- and
final-state interactions from gluon-exchange, normally neglected in the parton
model, have a profound effect in QCD hard-scattering reactions, leading to
leading-twist single-spin asymmetries, diffractive deep inelastic scattering,
diffractive hard hadronic reactions, the breakdown of the Lam Tung relation in
Drell-Yan reactions, and nuclear shadowing and non-universal
antishadowing--leading-twist physics not incorporated in the light-front
wavefunctions of the target computed in isolation. I also discuss tests of
hidden color in nuclear wavefunctions, the use of diffraction to materialize
the Fock states of a hadronic projectile and test QCD color transparency, and
anomalous heavy quark effects. The presence of direct higher-twist processes
where a proton is produced in the hard subprocess can explain the large
proton-to-pion ratio seen in high-centrality heavy-ion collisions.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 06:21:18 GMT"
},
{
"version": "v2",
"created": "Sat, 21 Jul 2007 07:50:29 GMT"
},
{
"version": "v3",
"created": "Tue, 24 Jul 2007 07:40:57 GMT"
}
] | 2009-09-11T00:00:00 | [
[
"Brodsky",
"Stanley J.",
""
]
] |
0707.2644 | Peter Kleinert | P. Kleinert and V.V. Bryksin | Oscillation of spin polarization in a two-dimensional hole gas under a
perpendicular magnetic field | 11 pages and 1 figure | null | 10.1088/0953-8984/19/47/476205 | null | cond-mat.mes-hall | null | Spin-charge coupling is studied for a strongly confined two-dimensional hole
gas subject to a perpendicular magnetic field. The study is based on
spin-charge coupled drift-diffusion equations derived from quantum-kinetic
equations in an exact manner. The spin-orbit interaction induces an extra
out-of-plane spin polarization. This contribution exhibits a persistent
oscillatory pattern in the strong-coupling regime.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 06:31:27 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Kleinert",
"P.",
""
],
[
"Bryksin",
"V. V.",
""
]
] |
0707.2645 | Christelle Guerret-Piecourt | F. Flores (PCP), D. Graebling (PCP), A. Allal (PCP), C.
Guerret-Pi\'ecourt (LTDS) | Modelization of flow electrification in a polymer melt | null | Journal of Physics D: Applied Physics 40 (19/04/2007) 2911 | 10.1088/0022-3727/40/9/037 | null | physics.class-ph | null | Flow electrification of polymer melts is an important side effect of polymer
processing. The studies dealing with this phenomenon are seldom and most of the
scientific work has been focused on flow electrification of aqueous and
insulating Newtonian liquids. From that prior art it is well established that
the flow electrification in Newtonian liquids is a consequence of the formation
of an ionic double layer. Convection of this layer induces the electrification
of the liquid at the outlet of the pipe. In those models, the key parameters
governing the flow electrification are thus the intrinsic electrical properties
of the polymer and the flow characteristics. In this work, we reconsider the
assumptions made previously and we propose a new approach to modelise the flow
electrification in the particular case of non-Newtonian polymer materials in
laminar flow conditions. We establish that, a key parameter for the
electrification quantification in the polymer melt is the shape of the velocity
profile. Additionally, in some cases, we show that a slip velocity at the
polymer/die wall interface must be considered to describe accurately the
electrification. As a consequence, we deduce that the slip velocity at the
interface can be calculated by measuring the electrification: this work gives
an alternative manner to measure the slip velocity during polymer flow.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 06:44:51 GMT"
}
] | 2007-07-19T00:00:00 | [
[
"Flores",
"F.",
"",
"PCP"
],
[
"Graebling",
"D.",
"",
"PCP"
],
[
"Allal",
"A.",
"",
"PCP"
],
[
"Guerret-Piécourt",
"C.",
"",
"LTDS"
]
] |
0707.2646 | Christelle Guerret-Piecourt | S. Tonon (PCP), A. Lavernhe-Gerbier (PCP), F. Flores (PCP), A. Allal
(PCP), C. Guerret-Pi\'ecourt (PCP) | Electrical charging during the sharkskin instability of a metallocene
melt | null | Journal of Non-Newtonian Fluid Mechanics 126 (10/03/2005) 63 | null | null | cond-mat.soft | null | Flow instabilities are widely studied because of their economical and
theoretical interest, however few results have been published about the polymer
electrification during the extrusion. Nevertheless the generation of the
electrical charges is characteristic of the interaction between the polymer
melt and the die walls. In our study, the capillary extrusion of a metallocene
polyethylene (mPE) through a tungsten carbide die is characterized through
accurate electrical measurements thanks a Faraday pail. No significant charges
are observed since the extrudate surface remains smooth. However, as soon as
the sharkskin distortion appears, measurable charges are collected (around 5
10-8 C/m2). Higher level of charges are measured during the spurt or the
gross-melt fracture (g.m.f) defects. This work is focused on the electrical
charging during the sharkskin instability. The variation of the electrical
charges versus the apparent wall shear stress is investigated for different die
geometries. This curve exhibits a linear increase, followed by a sudden growth
just before the onset of the spurt instability. This abrupt charging
corresponds also to the end of the sharkskin instability. It is also well-known
that wall slip appears just at the same time, with smaller velocity values than
during spurt flow. Our results indicate that electrification could be a
signature of the wall slip. We show also that the electrification curves can be
shifted according to the time-temperature superposition principle, leading to
the conclusion that molecular features of the polymer are also involved in this
process.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 06:45:50 GMT"
}
] | 2007-07-19T00:00:00 | [
[
"Tonon",
"S.",
"",
"PCP"
],
[
"Lavernhe-Gerbier",
"A.",
"",
"PCP"
],
[
"Flores",
"F.",
"",
"PCP"
],
[
"Allal",
"A.",
"",
"PCP"
],
[
"Guerret-Piécourt",
"C.",
"",
"PCP"
]
] |
0707.2647 | Yannick Ponty | Yannick Ponty (OCA), Thierry Passot (OCA), Pierre-Louis Sulem | A new instability for finite Prandtl number rotating convection with
free-slip boundary conditions | null | Physics of Fluids 9, 1 (01/01/1997) 67-75 | 10.1063/1.869176 | null | nlin.PS | null | Rolls in finite Prandtl number rotating convection with free-slip top and
bottom boundary conditions are shown to be unstable with respect to small angle
perturbations for any value of the rotation rate. This instability is driven by
the horizontal mean flow whose estimation requires a special singular
perturbation analysis.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 06:46:39 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Ponty",
"Yannick",
"",
"OCA"
],
[
"Passot",
"Thierry",
"",
"OCA"
],
[
"Sulem",
"Pierre-Louis",
""
]
] |
0707.2648 | Jyotishman Bhowmick | Debashish Goswami, Jyotishman Bhowmick | Quantum Isometry Groups: Examples and Computations | minor corrections and notational changes made; results of section 3
strengthened by relaxing the assumption of nuclearity | Commun.Math.Phys.285, 421- 444(2009) | null | null | math.QA math-ph math.MP | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | In this follow-up of the article: Quantum Group of Isometries in Classical
and Noncommutative Geometry(arXiv:0704.0041) by Goswami, where quantum isometry
group of a noncommutative manifold has been defined, we explicitly compute such
quantum groups for a number of classical as well as noncommutative manifolds
including the spheres and the tori. It is also proved that the quantum isometry
group of an isospectral deformation of a (classical or noncommutative) manifold
is a suitable deformation of the quantum isometry group of the original
(undeformed) manifold.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 06:47:31 GMT"
},
{
"version": "v2",
"created": "Sat, 27 Oct 2007 05:04:09 GMT"
},
{
"version": "v3",
"created": "Mon, 23 Jun 2008 05:52:04 GMT"
},
{
"version": "v4",
"created": "Fri, 30 Jan 2009 11:49:30 GMT"
}
] | 2009-01-30T00:00:00 | [
[
"Goswami",
"Debashish",
""
],
[
"Bhowmick",
"Jyotishman",
""
]
] |
0707.2649 | Christelle Guerret-Piecourt | Christelle Guerret-Piecourt (IFoS), Sandrine Bec (LTDS), Daniel
Treheux (IFoS) | Electrical charges and tribology of insulating materials | null | Comptes Rendus de l Acad\'emie des Sciences - Series IV - Physics
t2, S\'erie IV (05/07/2001) 761-774 | null | null | physics.class-ph | null | Electrical charges generation occurring during contact and friction of
insulating materials has been identified for a long time. However the
contribution of these electrical charges to the friction behaviour is usually
neglected in the energetical balances. Based on published results and on our
own experimental results on the ability of the dielectric materials to trap
charges, we show in this study that the interaction energy during friction
depends markedly on these trapped charges. Eventually, we propose the
complementary use of the "mirror " method and of surface forces measurements to
obtain a quantitative evaluation of this contribution. dielectric behaviour /
friction / triboelectrification / interfacial interactions / surface free
energy / space charge / surface forces
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 06:47:47 GMT"
}
] | 2007-07-19T00:00:00 | [
[
"Guerret-Piecourt",
"Christelle",
"",
"IFoS"
],
[
"Bec",
"Sandrine",
"",
"LTDS"
],
[
"Treheux",
"Daniel",
"",
"IFoS"
]
] |
0707.2650 | Carles Rovira | D. Marquez-Carreras, C. Rovira | Iterated logarithm law for anticipating stochastic differential
equations | null | null | null | null | math.PR | null | We prove a functional law of iterated logarithm for the following kind of
anticipating stochastic differential equations
$$\xi^u_t=X_0^u+\frac{1}{\sqrt{\log\log u}}\sum_{j=1}^k \int_0^{t}
A_j^u(\xi^u_s)\circ dW_{s}^j+ \int_0^{t} A_0^u(\xi^u_s)ds,$$ where $u>e$,
$W=\{(W_t^1,...,W_t^k), 0\le t\le 1\}$ is a standard $k$-dimensional Wiener
process, $A_0^u,A_1^u,..., A_k^u:\mathbb{R}^d\longrightarrow \mathbb{R}^d$ are
functions of class $\mathcal{C}^2$ with bounded partial derivatives up to order
2, $X_0^u$ is a random vector not necessarily adapted and the first integral is
a generalized Stratonovich integral .
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 06:50:22 GMT"
}
] | 2007-07-19T00:00:00 | [
[
"Marquez-Carreras",
"D.",
""
],
[
"Rovira",
"C.",
""
]
] |
0707.2651 | Issha Kayo | Issha Kayo, Naohisa Inada, Masamune Oguri, Patrick B. Hall,
Christopher S. Kochanek, Gordon T. Richards, Donald P. Schneider, Donald G.
York, and Kaike Pan | A New Quadruply Lensed Quasar: SDSSJ125107.57+293540.5 | 19 pages, 7 figures, AJ accepted | Astron.J.134:1515-1521,2007 | 10.1086/521652 | null | astro-ph | null | We report the discovery of a quadruply imaged quasar,
SDSSJ125107.57+293540.5, selected from the Sloan Digital Sky Survey. Follow-up
imaging reveals that the system consists of four blue point-like components in
a typical cusp lens geometry surrounding a central red galaxy. The source
redshift is 0.802 and the lens redshift is 0.410. The maximum image separation
between the lensed components is 1"79. While the image configuration is well
reproduced by standard mass models with reasonable parameter values, the flux
ratios predicted by these models differ from the observed ratios in all bands.
This is suggestive of small-scale structures in this lens, although the
definitive identification of the anomaly requires more accurate photometry and
astrometry.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 07:03:59 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Kayo",
"Issha",
""
],
[
"Inada",
"Naohisa",
""
],
[
"Oguri",
"Masamune",
""
],
[
"Hall",
"Patrick B.",
""
],
[
"Kochanek",
"Christopher S.",
""
],
[
"Richards",
"Gordon T.",
""
],
[
"Schneider",
"Donald P.",
""
],
[
"York",
"Donald G.",
""
],
[
"Pan",
"Kaike",
""
]
] |
0707.2652 | Ansgar Reiners | A. Reiners, D. Homeier, P.H. Hauschildt, F. Allard | A high resolution spectral atlas of brown dwarfs | 17 pages, 11 figures, accepted by A&A, reduced figure quality for
arXiv | null | 10.1051/0004-6361:20077963 | null | astro-ph | null | We present a UVES/VLT high resolution atlas of three L dwarfs and one T dwarf
system, spectral classes at which most of the objects are brown dwarfs. Our
atlas covers the optical region from H$\alpha$ up to the near infrared at 1
$\mu$m. We present spectral details of ultra-cool atmospheres at very high
resolution ($R \sim 33 000$) and compare the spectra to model calculations. Our
comparison shows that molecular features from VO and CaH, and atomic features
from Cs and Rb are reasonably well fit by current models. On the other hand,
features due to TiO, CrH, and water, and atomic Na and K reveal large
discrepancies between model calculations and our observations.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 07:07:40 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Reiners",
"A.",
""
],
[
"Homeier",
"D.",
""
],
[
"Hauschildt",
"P. H.",
""
],
[
"Allard",
"F.",
""
]
] |
0707.2653 | Anatoly Kochubei | Anatoly N. Kochubei | A Non-Archimedean Wave Equation | 17 pages; the final version, to appear in Pacif. J. Math | null | null | null | math.NT math.AP | null | Let K be a non-Archimedean local field with the normalized absolute value
$|\cdot |$. It is shown that a ``plane wave'' $f(t+\omega_1 x_1+...
+\omega_nx_n)$, where f is a Bruhat-Schwartz complex-valued test function on K,
$(t,x_1,..., x_n)\in K^{n+1}$, $\max\limits_{1\le j\le n}|\omega_j|=1$,
satisfies, for any f, a certain homogeneous pseudo-differential equation, an
analog of the classical wave equation. A theory of the Cauchy problem for this
equation is developed.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 07:16:06 GMT"
},
{
"version": "v2",
"created": "Thu, 6 Dec 2007 06:26:40 GMT"
}
] | 2007-12-06T00:00:00 | [
[
"Kochubei",
"Anatoly N.",
""
]
] |
0707.2654 | Giorgio Capon Dr. | Kloe Collaboration | The measurement of the absolute branching ratio of the K+ to pi+ pi0
(gamma) decay at KLOE | Contributed paper to Lepton-Photon 2007 | null | null | null | hep-ex | null | The preliminary result on the absolute branching ratio of the decay K+ to pi+
pi0 (gamma), obtained by the KLOE experiment operating at the DAPHNE Frascati
Phi-Factory, is presented.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 07:19:44 GMT"
}
] | 2012-08-27T00:00:00 | [
[
"Kloe Collaboration",
"",
""
]
] |
0707.2655 | Jens Schubert | The BABAR Collaboration, B. Aubert, et al | Measurement of the Decay B- --> D*0 e- nubar | 8 pages, 2 postscript figures, submitted to EPS2007 | null | null | BABAR-CONF-07/002, SLAC-PUB-12667 | hep-ex | null | Using 226 million $B\bar{B}$ events recorded on the $\Upsilon(4S)$ resonance
with the BABAR detector at the SLAC $e^+e^-$ storage rings PEPII, we
reconstruct $B^-\to D^{*0} e^-\bar\nu_e$ decays using the decay chain
$D^{*0}\to{}D^0{}\pi^0$ and $D^{0}\to{}K^-\pi^+$. From the dependence of their
differential rate on $w$, the product of the four-velocities of $B^-${} and
$D^{*0}$, and using the description of the form factor $F(w)$ by Caprini et
al., we obtain the preliminary results $\rho^2_{A_1} = 1.15\pm 0.06 \pm 0.08$,
$F(1)\cdot|V_{cb}| = (36.3\pm 0.6 \pm 1.4)\cdot 10^{-3}$, and ${\cal B}(B^-\to
D^{*0} e^-\bar\nu_e) = (5.71\pm 0.08\pm 0.41)%$. The first errors are
statistical and the second ones are systematic. \\
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 07:23:48 GMT"
}
] | 2007-07-19T00:00:00 | [
[
"The BABAR Collaboration",
"",
""
],
[
"Aubert",
"B.",
""
]
] |
0707.2656 | Arunava Goswami | Ayesha Rahman, Dipankar Seth, Nitai Debnath, C. Ulrichs, I. Mewis, R.
L. Brahmachary and A. Goswami | Nanosilica mops up host lipids and fights baculovirus: a B. mori model | 4 pages, 1 figure, 2 tables | null | null | null | q-bio.BM q-bio.MN | null | Malaria and other parasites, including virus often induce an increase in host
lipids which the invaders use to their own advantage. We obtained encouraging
results in our investigations on bird malaria with a new approach namely the
use of nanosilica to mop up excess host lipids. While this project is
continuing we have investigated another, simpler system namely silkworms which
suffer from a deadly baculovirus, BmNPV. This virus decimates the infected
population within 24 hours or so and no known antibiotic antidote or
genetically resistant strain of silkworm3 exists. We report here a partial
success, which is worth following up. Our rationale, we believe, has a broad
and interdisciplinary appeal, for, this nanosilica treatment might be used
together with other arsenals on all sorts of virus which take advantage of
enhanced host lipids. It has not escaped our notice that Ebola and HIV also
belong to this category. Nanoparticles are being preferentially harnessed,
because they offer a greater surface area, circulate more easily and in
lepidopteran system4 they are removed within 24 hours from the body. Lawry
surmised, on cogent theoretical grounds that particles significantly smaller
than micron order would be less harmful in the hemocoele. Furthermore, Hui-peng
et al. pointed out that lipase treatment, the only viable option for
controlling BmNPV interferes in hormonal balance and cannot be applied to pre
molting stage.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 07:25:30 GMT"
}
] | 2007-07-19T00:00:00 | [
[
"Rahman",
"Ayesha",
""
],
[
"Seth",
"Dipankar",
""
],
[
"Debnath",
"Nitai",
""
],
[
"Ulrichs",
"C.",
""
],
[
"Mewis",
"I.",
""
],
[
"Brahmachary",
"R. L.",
""
],
[
"Goswami",
"A.",
""
]
] |
0707.2657 | John Norris | John E. Norris, N. Christlieb, A. J. Korn, K. Eriksson, M. S. Bessell,
Timothy C. Beers, L. Wisotzki, and D. Reimers | HE 0557-4840 - Ultra-Metal-Poor and Carbon-Rich | Submitted to Astrophysical Journal. 52 pages (41 text, 11 figures) | null | 10.1086/521919 | null | astro-ph | null | We report the discovery and high-resolution, high S/N, spectroscopic analysis
of the ultra-metal-poor red giant HE 0557-4840, which is the third most
heavy-element deficient star currently known. Its atmospheric parameters are
T_eff = 4900 K, log g = 2.2, and [Fe/H]= -4.75. This brings the number of stars
with [Fe/H] < -4.0 to three, and the discovery of HE 0557-4840 suggests that
the metallicity distribution function of the Galactic halo does not have a
"gap" between [Fe/H] = -4.0, where several stars are known, and the two most
metal-poor stars, at [Fe/H] ~ -5.3. HE 0557-4840 is carbon rich - [C/Fe] = +1.6
- a property shared by all three objects with [Fe/H] < -4.0, suggesting that
the well-known increase of carbon relative to iron with decreasing [Fe/H]
reaches its logical conclusion - ubiquitous carbon richness - at lowest
abundance. We also present abundances (nine) and limits (nine) for a further 18
elements. For species having well-measured abundances or strong upper limits,
HE 0557-4840 is "normal" in comparison with the bulk of the stellar population
at [Fe/H] ~ -4.0 - with the possible exception of Co. We discuss the
implications of these results for chemical enrichment at the earliest times, in
the context of single ("mixing and fallback") and two-component enrichment
models. While neither offers a clear solution, the latter appears closer to the
mark. Further data are required to determine the oxygen abundance and improve
that of Co, and hence more strongly constrain the origin of this object.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 07:27:26 GMT"
},
{
"version": "v2",
"created": "Thu, 19 Jul 2007 03:54:34 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Norris",
"John E.",
""
],
[
"Christlieb",
"N.",
""
],
[
"Korn",
"A. J.",
""
],
[
"Eriksson",
"K.",
""
],
[
"Bessell",
"M. S.",
""
],
[
"Beers",
"Timothy C.",
""
],
[
"Wisotzki",
"L.",
""
],
[
"Reimers",
"D.",
""
]
] |
0707.2658 | Arunava Goswami | Ayesha Rahman, Dipankar Seth, Nitai Debnath, C. Ulrichs, I. Mewis, R.
L. Brahmachary and A. Goswami | Nanosilica mop up host lipids and fights baculovirus | null | null | null | null | q-bio.BM q-bio.MN | null | Various types of surface functionalized nanosilica (50-60 nm size with 3-10
nm inner pore size range) have been used to kill insect pests by sucking up
cuticular lipids and breaking the water barrier. We have also utilized
nanosilica for mopping up host lipids induced by the malarial parasite, P.
gallinaceum in poultry birds; VLDL cholesterol and serum triglycerides are
brought back to the normal level with a concomitant check in parasite growth.
While this work continues, we have explored another more convenient system,
silkworm (Bombyx mori) that is frequently decimated by a baculovirus, NPV for
which no antidote is known so far. Here, too, viral infection enhances host
lipids. Eight different types of nanosilica were injected in the virus infected
silkworm (batches of 10 worms) after ensuring 100% survival up to cocoon
formation in control larvae (injected with the same volume of ethanol, the
medium of nanosilica). Of these 8, AL60102 and AL60106, have the most marked
effect on infected silkworm, both as prophylactic and pharmaceutical agents.
Normal larvae injected with these nanosilica survive up to cocoon formation.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 07:31:27 GMT"
}
] | 2007-07-19T00:00:00 | [
[
"Rahman",
"Ayesha",
""
],
[
"Seth",
"Dipankar",
""
],
[
"Debnath",
"Nitai",
""
],
[
"Ulrichs",
"C.",
""
],
[
"Mewis",
"I.",
""
],
[
"Brahmachary",
"R. L.",
""
],
[
"Goswami",
"A.",
""
]
] |
0707.2659 | Arunava Goswami | Dipankar Seth, Mritunjay Mandal, Nitai Debnath, Ayesha Rahman, N. K.
Sasmal, Sunit Mukhopadhyaya, and Arunava Goswami | Control of rodent sleeping sickness disease by surface functionalized
amorphous nanosilica | 02 pages, 01 table, 781 words | null | null | null | q-bio.MN q-bio.BM | null | Wild animals, pets, zoo animals and mammals of veterinary importance heavily
suffer from trypanosomiasis. Drugs with serious side effects are currently
mainstay of therapies used by veterinarians. Trypanosomiasis is caused by
Trypanosoma sp. leading to sleeping sickness in humans. Surface modified
(hydrophobic and lipophilic) amorphous nanoporous silica molecules could be
effectively used as therapeutic drug for combating trypanosomiasis. The
amorphous nanosilica was developed by top-down approach using volcanic soil
derived silica (Advasan; 50- 60 nm size with 3-10 nm inner pore size range) and
diatomaceous earth (FS; 60-80 nm size with 3-5 nm inner pore size range) as
source materials. According to WHO and USDA standards amorphous silica has long
been used as feed additives for several veterinary industries and considered to
be safe for human consumption. The basic mechanism of action of these
nanosilica molecules is mediated by the physical absorption of HDL components
in the lipophilic nanopores of nanosilica. This reduces the supply of the host
derived cholesterol, thus limiting the growth of the Trypanosoma sp. in vivo.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 07:38:06 GMT"
}
] | 2007-07-19T00:00:00 | [
[
"Seth",
"Dipankar",
""
],
[
"Mandal",
"Mritunjay",
""
],
[
"Debnath",
"Nitai",
""
],
[
"Rahman",
"Ayesha",
""
],
[
"Sasmal",
"N. K.",
""
],
[
"Mukhopadhyaya",
"Sunit",
""
],
[
"Goswami",
"Arunava",
""
]
] |
0707.2660 | Eiji Onodera | Eiji Onodera | A third-order dispersive flow for closed curves into K\"ahler manifolds | 25pages, final version | null | null | null | math.AP | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | This paper is devoted to studying the initial value problem for a third-order
dispersive equation for closed curves into K\"ahler manifolds. This equation is
a geometric generalization of a two-sphere valued system modeling the motion of
vortex filament. We prove the local existence theorem by using geometric
analysis and classical energy method.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 07:38:15 GMT"
},
{
"version": "v2",
"created": "Wed, 19 Dec 2007 06:31:36 GMT"
},
{
"version": "v3",
"created": "Mon, 28 Jul 2008 09:57:26 GMT"
}
] | 2008-07-28T00:00:00 | [
[
"Onodera",
"Eiji",
""
]
] |
0707.2661 | Michael Le Bars | M. Le Bars and P. Le Gal | Experimental analysis of the Strato-rotational Instability in a
cylindrical Couette flow | 4 pages, 4 figures. PRL in press 2007 | Phys.Rev.Lett.99:064502,2007 | 10.1103/PhysRevLett.99.064502 | null | astro-ph | null | This study is devoted to the experimental analysis of the Strato-rotational
Instability (SRI). This instability affects the classical cylindrical Couette
flow when the fluid is stably stratified in the axial direction. In agreement
with recent theoretical and numerical analyses, we describe for the first time
in detail the destabilization of the stratified flow below the Rayleigh line
(i.e. the stability threshold without stratification). We confirm that the
unstable modes of the SRI are non axisymmetric, oscillatory, and take place as
soon as the azimuthal linear velocity decreases along the radial direction.
This new instability is relevant for accretion disks.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 07:41:41 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Bars",
"M. Le",
""
],
[
"Gal",
"P. Le",
""
]
] |
0707.2662 | Gorsky Eugeny | E. Gorsky | On the S_n-equivariant Euler characteristic of M_{2,n} | 14 pages | null | null | null | math.AG | null | The Getzler's formula relates the S_n-equivariant Hodge-Deligne polynomial of
the space of ordered tuples of distinct points on a given variety X with the
Hodge-Deligne polynomial of X. We obtain the analogue of this formula for the
case when X has a nontrivial automorphism group. Collecting together all strata
of $\mathcal{M}_2$ with different automorphism groups, we derive a formula for
the S_n-equivariant Euler characteristic of $\mathcal{M}_{2,n}$.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 07:49:54 GMT"
}
] | 2007-07-19T00:00:00 | [
[
"Gorsky",
"E.",
""
]
] |
0707.2663 | Alexandre Popier | Boualem Djehiche, Said Hamadene, Alexandre Popier | A Finite Horizon Optimal Multiple Switching Problem | 26 pages | null | null | null | math.PR math.OC | null | We consider the problem of optimal multiple switching in finite horizon, when
the state of the system, including the switching costs, is a general adapted
stochastic process. The problem is formulated as an extended impulse control
problem and completely solved using probabilistic tools such as the Snell
envelop of processes and reflected backward stochastic differential equations.
Finally, when the state of the system is a Markov diffusion process, we show
that the vector of value functions of the optimal problem is a viscosity
solution to a system of variational inequalities with inter-connected
obstacles.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 08:04:58 GMT"
}
] | 2007-07-19T00:00:00 | [
[
"Djehiche",
"Boualem",
""
],
[
"Hamadene",
"Said",
""
],
[
"Popier",
"Alexandre",
""
]
] |
0707.2664 | Baojiu Li | Baojiu Li, John D. Barrow, David F. Mota | The Cosmology of Ricci-Tensor-Squared Gravity in the Palatini
Variational Approach | 11 pages, 2 figures; version to appear in Phys. Rev. D | Phys.Rev.D76:104047,2007 | 10.1103/PhysRevD.76.104047 | null | gr-qc astro-ph | null | We consider the cosmology of the Ricci-tensor-squared gravity in the Palatini
variational approach. The gravitational action of standard general relativity
is modified by adding a function f(R^abR_ab) to the Einstein-Hilbert action,
and the Palatini variation is used to derive the field equations. A general
method of obtaining the background and first-order covariant and
gauge-invariant perturbation equations is outlined. As an example, we consider
the cosmological constraints on such theories arising from the supernova type
Ia and cosmic microwave background observations. We find that the best fit to
the data is a non-null leading-order correction to Einstein gravity, but the
current data exhibit no significant preference over the concordance model. The
growth of non-relativistic matter density perturbations at late times is also
analyzed, and we find that a scale-dependent (positive or negative)
sound-speed-squared term generally appears in the growth equation for
small-scale density perturbations. We also estimate the observational bound
imposed by the matter power spectrum for the model with f(R^abR_ab) =
alpha(R^abR_ab)^beta to be roughly |\beta| \lesssim O(10^{-5}) so long as the
dark matter does not possess compensating anisotropic stresses.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 08:01:22 GMT"
},
{
"version": "v2",
"created": "Sun, 7 Oct 2007 18:20:18 GMT"
},
{
"version": "v3",
"created": "Fri, 12 Oct 2007 15:22:00 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Li",
"Baojiu",
""
],
[
"Barrow",
"John D.",
""
],
[
"Mota",
"David F.",
""
]
] |
0707.2665 | Manuel A. Valle | Manuel A. Valle | Hydrodynamic fluctuations in relativistic superfluids | 13 pages, no figures, two references added | Phys.Rev.D77:025004,2008 | 10.1103/PhysRevD.77.025004 | null | hep-ph cond-mat.other | null | The Hamiltonian formulation of superfluids based on noncanonical Poisson
brackets is studied in detail. The assumption that the momentum density is
proportional to the flow of the conserved energy is shown to lead to the
covariant relativistic theory previously suggested by Khalatnikov, Lebedev and
Carter, and some potentials in this theory are given explicitly. We discuss
hydrodynamic fluctuations in the presence of dissipative effects and we derive
the corresponding set of hydrodynamic correlation functions. Kubo relations for
the transport coefficients are obtained.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 08:04:13 GMT"
},
{
"version": "v2",
"created": "Thu, 26 Jul 2007 07:49:44 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Valle",
"Manuel A.",
""
]
] |
0707.2666 | Antonio Padilla | Ruth Gregory, Nemanja Kaloper, Robert C. Myers and Antonio Padilla | A New Perspective on DGP Gravity | 37 pages, 3 figures. References added. Some points clarified | JHEP 0710:069,2007 | 10.1088/1126-6708/2007/10/069 | null | hep-th astro-ph gr-qc hep-ph | null | We examine brane induced gravity on codimension-1 branes, a.k.a DGP gravity,
as a theory of five-dimensional gravity containing a certain class
four-dimensional branes. From this perspective, the model suffers from a number
of pathologies which went unnoticed before. By generalizing the 5D geometry
from Minkowski to Schwarzschild, we find that when the bulk mass is large
enough, the brane hits a pressure singularity at finite radius. Further, on the
self-accelerating branch, the five-dimensional energy is unbounded from below,
implying that the self-accelerating backgrounds are unstable. Even in an empty
Minkowski bulk, standard Euclidean techniques suggest that the spontaneous
nucleation of self-accelerating branes is unsuppressed. If so, quantum effects
will strongly modify any classical intuition about the theory. We also note
that unless considered as Z_2-orbifold boundaries, self-accelerating branes
correspond to `wormhole' configurations, which introduces the usual problematic
issues associated with wormholes. Altogether these pathologies present a
serious challenge that any proposed UV completion of the DGP model must
overcome.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 08:25:18 GMT"
},
{
"version": "v2",
"created": "Tue, 7 Aug 2007 09:19:20 GMT"
}
] | 2009-11-18T00:00:00 | [
[
"Gregory",
"Ruth",
""
],
[
"Kaloper",
"Nemanja",
""
],
[
"Myers",
"Robert C.",
""
],
[
"Padilla",
"Antonio",
""
]
] |
0707.2667 | David Carpentier | David Carpentier (Phys-ENS), Pierre Le Doussal (LPTENS) | Electromagnetic Coulomb Gas with Vector Charges and "Elastic''
Potentials : Renormalization Group Equations | null | null | 10.1016/j.nuclphysb.2007.10.019 | null | cond-mat.stat-mech cond-mat.dis-nn | null | We present a detailed derivation of the renormalization group equations for
two dimensional electromagnetic Coulomb gases whose charges lie on a triangular
lattice (magnetic charges) and its dual (electric charges). The interactions
between the charges involve both angular couplings and a new electromagnetic
potential. This motivates the denomination of ``elastic'' Coulomb gas. Such
elastic Coulomb gases arise naturally in the study of the continuous melting
transition of two dimensional solids coupled to a substrate, either
commensurate or with quenched disorder.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 08:08:52 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Carpentier",
"David",
"",
"Phys-ENS"
],
[
"Doussal",
"Pierre Le",
"",
"LPTENS"
]
] |
0707.2668 | Miroslav Pardy | Miroslav Pardy | The photo-electric effect in the bi-layer graphite | 10 pages | null | null | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We derive the differential probability of the photoelectric effect realized
at the very low temperature of double graphene in the very strong magnetic
field. The relation of this effect to the elementary particle physics, nuclear
physics and Einstein gravity is mentioned. Our approach is the analogue of the
Landau discovery of the diamagnetism, where Landau supposed the parabolic
dispersion relations for the model of diamagnetism.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 08:25:39 GMT"
},
{
"version": "v2",
"created": "Fri, 8 Aug 2008 08:54:10 GMT"
}
] | 2008-08-08T00:00:00 | [
[
"Pardy",
"Miroslav",
""
]
] |
0707.2669 | Claire Scheid | C.Scheid, P.Witomski | A proof of the invariance of the contact angle in Electrowetting | 28 pages, 9 figures | null | null | null | math.CA math.OC | null | We prove the invariance of the contact angle in liquid-solid wetting
phenomena : an electrified droplet is spreading on a solid surface. The drop is
minimizing its energy. We express the differential of this energy with respect
to the shape of the drop and deduce necessary conditions for optimality . By
variational method, using well-chosen test functions, we obtain the main result
about the contact angle between the drop and the solid.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 08:30:41 GMT"
}
] | 2007-07-19T00:00:00 | [
[
"Scheid",
"C.",
""
],
[
"Witomski",
"P.",
""
]
] |
0707.2670 | Jan Erik Sundermann | The BABAR Collaboration, B. Aubert, et al | Measurement of Moments of the Hadronic-Mass and -Energy Spectrum in
Inclusive Semileptonic $\bar{B} \to X_{c} \ell^{-} \bar{\nu}$ Decays | 21 pages, 11 postscript figures, submitted to EPS-HEP2007 | null | null | BABAR-CONF-07/003, SLAC-PUB-12668 | hep-ex | null | We present a measurement of moments of the inclusive hadronic-mass and
-energy spectrum in semileptonic $\bar{B} \to X_{c} \ell^{-} \bar{\nu}$ decays.
This study is based on a sample of 232 million $\Upsilon(4S) \to B\bar{B}$
decays recorded by the BABAR detector at the PEP-II $e^+e^-$-storage rings. We
reconstruct the semileptonic decay by identifying a lepton in events tagged by
a fully reconstructed hadronic decay of the second $B$ meson. We report
preliminary results for the moments $<m_X^k>$ with $k=1,...,6$ and $<n_X^k>$
with $k=2,4,6$ and $n_X^2 = m_X^2 c^4 - 2 \tilde{\Lambda} E_X +
\tilde{\Lambda}^2$, with $m_X$ the mass of the hadronic system, $E_X$ its
energy, and $\tilde\Lambda$ a constant of $0.65 \mathrm{GeV}$, for different
minimal lepton momenta between 0.8 and $1.9 \mathrm{GeV}/c$ measured in the
$B$-meson rest frame. These are predicted in the framework of a Heavy Quark
Expansion (HQE), which allows the extraction of the total semileptonic
branching fraction, the CKM-matrix element $|V_{cb}|$, and the quark masses
$m_b$ and $m_c$, together with the dominant non-perturbative HQE parameters. We
find as preliminary results $|V_{cb}| = (41.88 \pm 0.81) \cdot 10^{-3}$ and
$m_b = (4.552 \pm 0.055) \mathrm{GeV}/c^2$.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 08:35:06 GMT"
}
] | 2007-07-19T00:00:00 | [
[
"The BABAR Collaboration",
"",
""
],
[
"Aubert",
"B.",
""
]
] |
0707.2671 | Hiroyuki Abe | Hiroyuki Abe, Tetsutaro Higaki, Tatsuo Kobayashi | More about F-term uplifting | 22 pages; a sign error in the evaluation of F^X and the related part
corrected, references added | Phys.Rev.D76:105003,2007 | 10.1103/PhysRevD.76.105003 | YITP-07-43, TU-794, KUNS-2087 | hep-th hep-ph | null | We study moduli stabilization and a realization of de Sitter vacua in
generalized F-term uplifting scenarios of the KKLT-type anti-de Sitter vacuum,
where the uplifting sector X directly couples to the light K\"ahler modulus T
in the superpotential through, e.g., stringy instanton effects. F-term
uplifting can be achieved by a spontaneous supersymmetry breaking sector, e.g.,
the Polonyi model, the O'Raifeartaigh model and the Intriligator-Seiberg-Shih
model. Several models with the X-T mixing are examined and qualitative features
in most models {\it even with such mixing} are almost the same as those in the
KKLT scenario. One of the quantitative changes, which are relevant to the
phenomenology, is a larger hierarchy between the modulus mass m_T and the
gravitino mass $m_{3/2}$, i.e., $m_T/m_{3/2} = {\cal O}(a^2)$, where $a \sim 4
\pi^2$. In spite of such a large mass, the modulus F-term is suppressed not
like $F^T = {\cal O}(m_{3/2}/a^2)$, but like $F^T = {\cal O}(m_{3/2}/a)$ for
$\ln (M_{Pl}/m_{3/2}) \sim a$, because of an enhancement factor coming from the
X-T mixing. Then we typically find a mirage-mediation pattern of gaugino masses
of ${\cal O}(m_{3/2}/a)$, while the scalar masses would be generically of
${\cal O}(m_{3/2})$.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 08:43:02 GMT"
},
{
"version": "v2",
"created": "Wed, 25 Jul 2007 09:58:54 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Abe",
"Hiroyuki",
""
],
[
"Higaki",
"Tetsutaro",
""
],
[
"Kobayashi",
"Tatsuo",
""
]
] |
0707.2672 | Max Wakefield | Max Wakefield and Masahiko Yoshinaga | The Jacobian ideal of a hyperplane arrangement | 5 pages | null | null | null | math.AC math.AG | null | The Jacobian ideal of a hyperplane arrangement is an ideal in the polynomial
ring whose generators are the partial derivatives of the arrangements defining
polynomial. In this article, we prove that an arrangement can be reconstructed
from its Jacobian ideal.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 08:38:09 GMT"
}
] | 2007-07-19T00:00:00 | [
[
"Wakefield",
"Max",
""
],
[
"Yoshinaga",
"Masahiko",
""
]
] |
0707.2673 | Luca Maccione | Luca Maccione (SISSA & INFN, Trieste), Stefano Liberati (SISSA & INFN,
Trieste), Annalisa Celotti (SISSA, Trieste), John G. Kirk (MPI, Heidelberg) | New constraints on Planck-scale Lorentz Violation in QED from the Crab
Nebula | 23 pages, 9 figures. v2: added comments and references, matches
version accepted by JCAP | JCAP0710:013,2007 | 10.1088/1475-7516/2007/10/013 | null | astro-ph gr-qc hep-ph hep-th | null | We set constraints on O(E/M) Lorentz Violation in QED in an effective field
theory framework. A major consequence of such assumptions is the modification
of the dispersion relations for electrons/positrons and photons, which in turn
can affect the electromagnetic output of astrophysical objects. We compare the
information provided by multiwavelength observations with a full and
self-consistent computation of the broad-band spectrum of the Crab Nebula. We
cast constraints of order 10^{-5} at 95% confidence level on the lepton Lorentz
Violation parameters.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 08:39:56 GMT"
},
{
"version": "v2",
"created": "Thu, 4 Oct 2007 06:34:32 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Maccione",
"Luca",
"",
"SISSA & INFN, Trieste"
],
[
"Liberati",
"Stefano",
"",
"SISSA & INFN,\n Trieste"
],
[
"Celotti",
"Annalisa",
"",
"SISSA, Trieste"
],
[
"Kirk",
"John G.",
"",
"MPI, Heidelberg"
]
] |
0707.2674 | Martyn Fogg | Martyn J. Fogg and Richard P. Nelson | The effect of type I migration on the formation of terrestrial planets
in hot-Jupiter systems | Accepted by A&A. 15 pages, 14 figures. Higher resolution pdf
available at http://www.users.globalnet.co.uk/~mfogg/7950fogg.pdf | A&A, 472, 1103-1015 (2007) | 10.1051/0004-6361:20077950 | null | astro-ph | null | Context: Our previous models of a giant planet migrating through an inner
protoplanet/planetesimal disk find that the giant shepherds a portion of the
material it encounters into interior orbits, whilst scattering the rest into
external orbits. Scattering tends to dominate, leaving behind abundant material
that can accrete into terrestrial planets. Aims: We add to the possible realism
of our model by simulating type I migration forces which cause an inward drift,
and strong eccentricity and inclination damping of protoplanetary bodies. This
extra dissipation might be expected to enhance shepherding at the expense of
scattering, possibly modifying our previous conclusions. Methods: We employ an
N-body code that is linked to a viscous gas disk algorithm capable of
simulating: gas accretion onto the central star; gap formation in the vicinity
of the giant planet; type II migration of the giant planet; type I migration of
protoplanets; and the effect of gas drag on planetesimals. We use the code to
re-run three scenarios from a previous work where type I migration was not
included. Results: The additional dissipation introduced by type I migration
enhances the inward shepherding of material but does not severely reduce
scattering. We find that > 50% of the solids disk material still survives the
migration in scattered exterior orbits: most of it well placed to complete
terrestrial planet formation at < 3 AU. The shepherded portion of the disk
accretes into hot-Earths, which survive in interior orbits for the duration of
our simulations. Conclusions: Water-rich terrestrial planets can form in the
habitable zones of hot-Jupiter systems and hot-Earths and hot-Neptunes may also
be present. These systems should be targets of future planet search missions.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 08:44:10 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Fogg",
"Martyn J.",
""
],
[
"Nelson",
"Richard P.",
""
]
] |
0707.2675 | Matteo Chieregato | M. Chieregato, M. Miranda and P. Jetzer | Q0045-3337: models including strong lensing by a spiral galaxy | 7 pages, 5 figures, accepted for publication on A&A | Astron.Astrophys.474:777-782,2007 | 10.1051/0004-6361:20066837 | null | astro-ph | null | Aims. Falomo et al. (2005) discovered a disk-like galaxy at ~ 1.2 arcsec from
the QSO Q0045-3337 by means of ESO VLT adaptive optics. They estimated a galaxy
Einstein radius (for a point mass) of comparable size, thus pointing up the
existence of a new, rare, spiral lens candidate, despite no evident image
splitting.
Here we discuss the possible lensing effect of the galaxy in some more
detail.
Methods. We performed two dimensional surface photometry on the VLT image of
the galaxy, confirming its spiral nature. We then verified if simple mass
models, partially constrained by observational data, require unrealistic
parameters to produce a still hidden second quasar image. We also evaluated the
respective viability of an instrumental or a lensing origin of the observed QSO
deformation.
Results. After galaxy model subtraction, we found a residual image, likely
not related to gravitational lensing. Existing data are not sufficient to
assess the presence of image splitting, nor to constrain the number of images
or discriminate between galaxy mass models.
Conclusion. Further observations are mandatory to progress in the study of
this remarkable system, that could shed more light on the lensing behaviour of
spiral galaxies.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 08:50:41 GMT"
}
] | 2010-01-15T00:00:00 | [
[
"Chieregato",
"M.",
""
],
[
"Miranda",
"M.",
""
],
[
"Jetzer",
"P.",
""
]
] |
0707.2676 | Frank Witte | I. Sturm and F.M.C. Witte | Groundstate splitting around rotating mini Blackholes | 10 pages submitted for publication as Letter | null | null | null | gr-qc astro-ph | null | In this letter we present the result of a spin-dependent groundstate-energy
calculation for fermionic boundstates in the spacetime around a rotating
blackhole. Using a slow rotation approximation and a minimax variational
approach we find boundstate energies of 0 to 5 percent of the fermions
flatspace restmass. The groundstate displays a spin-dependent splitting with an
energy difference of about 10 percent of the binding energy. For a dilute gas
of primordial mini blackholes with gravitationally bound electrons spin-flip
transitions could possibly give rise to observable signatures in the observed
soft X-ray spectrum for sources at cosmological distances.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 08:51:52 GMT"
}
] | 2007-07-19T00:00:00 | [
[
"Sturm",
"I.",
""
],
[
"Witte",
"F. M. C.",
""
]
] |
0707.2677 | Arnaud Pierens | Arnaud Pierens, Richard P. Nelson | On the migration of protoplanets embedded in circumbinary disks | 10 pages, 10 figures, accepted for publication in A&A | null | 10.1051/0004-6361:20077659 | null | astro-ph | null | We present the results of hydrodynamical simulations of low mass protoplanets
embedded in circumbinary accretion disks. The aim is to examine the migration
and long term orbital evolution of the protoplanets, in order to establish the
stability properties of planets that form in circumbinary disks. Simulations
were performed using a grid--based hydrodynamics code. First we present a set
of calculations that study how a binary interacts with a circumbinary disk. We
evolve the system for 10^5 binary orbits, which is the time needed for the
system to reach a quasi-equilibrium state. From this time onward the apsidal
lines of the disk and the binary are aligned, and the binary eccentricity
remains essentially unchanged with a value of e_b ~ 0.08. Once this stationary
state is obtained, we embed a low mass protoplanet in the disk and let it
evolve under the action of the binary and disk forces. We consider protoplanets
with masses of 5, 10 and 20 Earth masses. In each case, we find that inward
migration of the protoplanet is stopped at the edge of the tidally truncated
cavity formed by the binary. This effect is due to positve corotation torques,
which can counterbalance the net negative Lindblad torques in disk regions
where the surface density profile has a sufficiently large positive gradient.
Halting of migration occurs in a region of long-term stability, suggesting that
low mass circumbinary planets may be common, and that gas giant circumbinary
planets should be able to form in circumbinary disks.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 08:56:16 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Pierens",
"Arnaud",
""
],
[
"Nelson",
"Richard P.",
""
]
] |
0707.2678 | Joost van Duijn | J. van Duijn, N. Hur, J. W. Taylor, Y. Qiu, Q. Z. Huang, S.-W. Cheong,
C. Broholm and T. G. Perring | From Cooperative Paramagnet to N\'{e}el Order in Y_2Ru_2O_7 | 4 pages, 4 figures, submitted to PRB-RC | Physical Review B 77, 020405(R) (2008) | 10.1103/PhysRevB.77.020405 | null | cond-mat.str-el | null | Spin correlations in the pyrochlore antiferromagnet Y_2Ru_2O_7 with
Curie-Weiss temperature $\Theta_{CW}=-1100$ K and critical temperature T_N=77 K
were examined through neutron scattering. For $T_N<T<\Theta_{CW}/3$ the data
show spin relaxation with a rate $\hbar\Gamma= 1.17(9)k_BT$. For T<T_N spectral
weight moves to higher energies with substantial changes up to $4\times
k_BT_N$. For T<<T_N there is a $\Delta=11(1)$ meV energy gap and a pronounced
spectral maximum at 19.7 meV. Throughout the temperature range examined the
wave vector dependence of inelastic scattering exhibits a broad peak for
$Qd\approx 3.8$ (d is Ru-Ru spacing) consistent with dipolar spin correlations.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 09:01:51 GMT"
}
] | 2014-07-03T00:00:00 | [
[
"van Duijn",
"J.",
""
],
[
"Hur",
"N.",
""
],
[
"Taylor",
"J. W.",
""
],
[
"Qiu",
"Y.",
""
],
[
"Huang",
"Q. Z.",
""
],
[
"Cheong",
"S. -W.",
""
],
[
"Broholm",
"C.",
""
],
[
"Perring",
"T. G.",
""
]
] |
0707.2679 | Edward Boyce | E. R. Boyce (1), S. T. Myers (2), I. W. A. Browne (1), W. J. Stroman
(2, 3), N. J. Jackson (1) ((1) University of Manchester, Jodrell Bank
Observatory, (2) NRAO, (3) Iowa State University) | J0316+4328: a Probable "Asymmetric Double" Lens | Accepted to MNRAS Letters. 5 pages, 6 figures, 3 tables | 2007, MNRAS, 381, L55 | 10.1111/j.1745-3933.2007.00365.x | Jodrell Bank Preprint 2052 | astro-ph | null | We report a probable gravitational lens J0316+4328, one of 19 candidate
asymmetric double lenses (2 images at a high flux density ratio) from CLASS.
Observations with the Very Large Array (VLA), MERLIN and the Very Long Baseline
Array (VLBA) imply that J0316+4328 is a lens with high confidence. It has 2
images separated by 0.40", with 6 GHz flux densities of 62 mJy and 3.2 mJy. The
flux density ratio of ~19 (constant over the frequency range 6-22 GHz) is the
largest for any 2 image gravitational lens. High resolution optical imaging and
deeper VLBI maps should confirm the lensing interpretation and provide inputs
to detailed lens models. The unique configuration will give strong constraints
on the lens galaxy's mass profile.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 09:13:50 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Boyce",
"E. R.",
""
],
[
"Myers",
"S. T.",
""
],
[
"Browne",
"I. W. A.",
""
],
[
"Stroman",
"W. J.",
""
],
[
"Jackson",
"N. J.",
""
]
] |
0707.2680 | Giulia Migliori | G. Migliori, P. Grandi, G.C.G. Palumbo, G. Brunetti, C. Stanghellini | An X-ray view of Pictor A radio lobes: a spatially resolved study | 5 pages, 3 figures, to appear in the proceedings of Extragalactic
Jets: Theory and Observation from Radio to Gamma Ray, Girdwood (AK), May 2007 | null | null | null | astro-ph | null | A spatially resolved analysis of the lobes of the radio galaxy Pictor A has
been performed for the first time starting from a 50 ksec XMM-Newton
observation. Magnetic field, B_{IC}, particle density, particle to magnetic
field energy density ratios have been measured. Our study shows that B_{IC}
varies through the lobes. On the contrary, a rather uniform distribution of the
particles is observed. In both the lobes, the equipartition magnetic field,
B_{eq}, is bigger than the Inverse Compton value, B_{IC}, calculated from the
radio to X-ray flux ratio.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 09:03:40 GMT"
}
] | 2007-07-19T00:00:00 | [
[
"Migliori",
"G.",
""
],
[
"Grandi",
"P.",
""
],
[
"Palumbo",
"G. C. G.",
""
],
[
"Brunetti",
"G.",
""
],
[
"Stanghellini",
"C.",
""
]
] |
0707.2681 | Omar Benhar | Omar Benhar, Marco Valli | Shear viscosity of neutron matter from realistic nucleon-nucleon
interactions | 4 pages, 4 figures. Corrected typos | Phys.Rev.Lett.99:232501,2007 | 10.1103/PhysRevLett.99.232501 | null | nucl-th astro-ph | null | The calculation of transport properties of Fermi liquids, based on the
formalism developed by Abrikosov and Khalatnikov, requires the knowledge of the
probability of collisions between quasiparticles in the vicinity of the Fermi
surface. We have carried out a numerical study of the shear viscosity of pure
neutron matter, whose value plays a pivotal role in determining the stability
of rotating neutron stars, in which these processes are described using a
state-of-the-art nucleon-nucleon potential model. Within our approach medium
modifications of the scattering cross section are consistently taken into
account, through an effective interaction obtained from the matrix elements of
the bare interaction between correlated states. Inclusion of medium effects
lead to a large increase of the viscosity at densities larger than $\sim 0.1$
fm^{-3}.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 09:05:04 GMT"
},
{
"version": "v2",
"created": "Thu, 26 Jul 2007 07:33:54 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Benhar",
"Omar",
""
],
[
"Valli",
"Marco",
""
]
] |
0707.2682 | Jean-Philippe Groby | Jean-Phiilppe Groby (CMAP), Dominique Lesselier (LSS) | Localization and characterization of simple defects in finite-size
photonic crystals | submitted to Journal of the Optical Society of America A | null | 10.1364/JOSAA.25.000146 | null | physics.optics | null | Structured materials like photonic crystals require for optimal use a high
precision both on position and optical characteristics of the components which
they are made of. Here, we present a simple tomographic algorithm, based on a
specific Green's function together with a first-order Born approximation, which
enables us to localize and characterize identical defects in finite-size
photonic crystals. This algorithm is proposed as a first step to the monitoring
of such materials. Illustrative numerical results show in particular some
possibility of focalization beyond the Rayleigh criterion.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 09:05:35 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Groby",
"Jean-Phiilppe",
"",
"CMAP"
],
[
"Lesselier",
"Dominique",
"",
"LSS"
]
] |
0707.2683 | Keiichi Yamamoto | Keiichi Yamamoto, Yoshiyuki Shibayama, Keiya Shirahama | Liquid-Solid Transition and Phase Diagram of ^4He Confined in Nanoporous
Glass | 4 pages, 4 figures, submitted to J. Phys. Soc. Jpn | null | 10.1143/JPSJ.77.013601 | null | cond-mat.mes-hall cond-mat.str-el | null | We have studied the liquid - solid (L-S) phase transition of ^4He confined in
nanoporous glass, which has interconnected nanopores of 2.5 nm in diameter. The
L-S boundary is determined by the measurements of pressure and thermal response
during slow cooling and warming. Below 1 K, the freezing pressure is elevated
to 1.2 MPa from the bulk freezing pressure, and appears to be independent of
temperature. The T-independent L-S boundary implies the existence of a
localized Bose-Einstein condensation state, in which long-range superfluid
coherence is destroyed by narrowness of the nanopores and random potential.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 09:09:48 GMT"
}
] | 2015-05-13T00:00:00 | [
[
"Yamamoto",
"Keiichi",
""
],
[
"Shibayama",
"Yoshiyuki",
""
],
[
"Shirahama",
"Keiya",
""
]
] |
0707.2684 | Ashley Willis | Ashley P. Willis and Rich R. Kerswell | Reply to Comment on 'Critical behaviour in the relaminarization of
localized turbulence in pipe flow' | 1 page, 1 figure | null | 10.1103/PhysRevLett.98.014501 | null | physics.flu-dyn | null | This is a Reply to Comment arXiv:0707.2642 by Hof et al. on Letter
arXiv:physics/0608292 which was subsequently published in Phys Rev Lett, 98,
014501 (2007).
In our letter it was reported that in pipe flow the median time $\tau$ for
relaminarisation of localised turbulent disturbances closely follows the
scaling $\tau\sim 1/(Re_c-Re)$. This conclusion was based on data from
collections of 40 to 60 independent simulations at each of six different
Reynolds numbers, Re. In the Comment, Hof et al. estimate $\tau$ differently
for the point at lowest Re. Although this point is the most uncertain, it forms
the basis for their assertion that the data might then fit an exponential
scaling $\tau\sim \exp(A Re)$, for some constant A, supporting Hof et al.
(2006) Nature, 443, 59. The most certain point (at largest Re) does not fit
their conclusion and is rejected. We clarify why their argument for rejecting
this point is flawed. The median $\tau$ is estimated from the distribution of
observations, and it is shown that the correct part of the distribution is
used. The data is sufficiently well determined to show that the exponential
scaling cannot be fit to the data over this range of Re, whereas the $\tau\sim
1/(Re_c-Re)$ fit is excellent, indicating critical behaviour and supporting
experiments by Peixinho & Mullin 2006.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 09:21:11 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Willis",
"Ashley P.",
""
],
[
"Kerswell",
"Rich R.",
""
]
] |
0707.2685 | Michele Bellazzini | Michele Bellazzini (INAF - Oss. Astr. di Bologna) | The surface brightness profile of the remote cluster NGC 2419 | Research Note, accepted for publication by A&A. 6 pages with 4
figures + 3 pages of Online Material (table) | null | 10.1051/0004-6361:20078130 | null | astro-ph | null | It is well known that the bright and remote Galactic globular cluster NGC2419
has a very peculiar structure. In particular its half-light radius is
significantly larger than that of ordinary globular clusters of similar
luminosity, being as large as that of the brightest nuclei of dwarf elliptical
galaxies. In this context it is particularly worth to check the reliability of
the existing surface brightness profiles for this cluster and of the available
estimates of its structural parameters. Combining different datasets I derive
the surface brightness profile going from the cluster center out to ~ 480
arcsec, i.e. ~25 core radii. (Abridged). The newly obtained surface brightness
profile is in excellent agreement with that provided by Trager, King &
Djorgovski for r>= 4 arcsec; it is best fitted by a King model having r_c=0.32
arcmin, mu_V(0)=19.55 and C=1.35. Also new independent estimates of the total
integrated V magnitude (V_t=10.47 +/- 0.07) and of the half-light radius
(r_h=0.96 arcmin +/- 0.2 arcmin) have been obtained. (Abridged). The structure
of NGC2419 is now reliably constrained by (at least) two fully independent
observational profiles that are in good agreement one with the other. Also the
overall agreement between structural parameters independently obtained by
different authors is quite satisfying.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 09:14:20 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Bellazzini",
"Michele",
"",
"INAF - Oss. Astr. di Bologna"
]
] |
0707.2686 | Luca Amendola | Cinzia Di Porto (U. Roma Tre, Italy), Luca Amendola (INAF/OAR, Italy) | Observational constraints on the linear fluctuation growth rate | 9 pages | Phys.Rev.D77:083508,2008 | 10.1103/PhysRevD.77.083508 | null | astro-ph | null | Several experiments in the near future will test dark energy through its
effects on the linear growth of matter perturbations. It is therefore important
to find simple and at the same time general parametrizations of the linear
growth rate. We show that a simple fitting formula that generalizes previous
expressions reproduces the growth function in models that allow for a growth
faster than standard, as for instance in scalar-tensor models. We use data from
galaxy and Lyman-$\alpha$ power spectra to constrain the linear growth rate. We
find $\gamma=0.6_{-0.3}^{+0.4}$ for the growth rate index and
$\eta=0.0_{-0.2}^{+0.3}$ for the additional growth parameter we introduce.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 09:24:57 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Di Porto",
"Cinzia",
"",
"U. Roma Tre, Italy"
],
[
"Amendola",
"Luca",
"",
"INAF/OAR, Italy"
]
] |
0707.2687 | Flavio Archilli Dr | The KLOE collaboration | Search for the K(S) --> e+e- decay with the KLOE detector at DAFNE | paper submitted to Lepton Photon 07 | Phys.Lett.B672:203-208,2009 | 10.1016/j.physletb.2009.01.037 | null | hep-ex | null | We present results of a direct search for the decay KS --> e+e- with the KLOE
detector, obtained with a sample of e+e- --> phi --> KSKL events produced at
DAFNE, the Frascati phi-factory, for an integrated luminosity of 1.3fb-1. The
Standard Model prediction for this decay is BR(KS --> e+e-) = 1.6*10^-15. The
search has been performed tagging the KS decays by simultaneous detection of a
KL interaction in the calorimeter. Background rejection has been optimized by
using both kinematic cuts and particle identification. At the end of the
analysis chain we find BR(KS --> e+e-) < 2.1*10^-8 at 90% CL, which improves by
a factor of ~7 on the previous best result, obtained by CPLEAR experiment.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 09:42:38 GMT"
}
] | 2012-08-27T00:00:00 | [
[
"The KLOE collaboration",
"",
""
]
] |
0707.2688 | B Pandey Dr | B. P. Pandey and Mark Wardle | Hall magnetohydrodynamics of partially ionized plasmas | 11 page, 1 figure, typos removed, numbers in tables revised; accepted
for publication in MNRAS | null | 10.1111/j.1365-2966.2008.12998.x | null | astro-ph | null | The Hall effect arises in a plasma when electrons are able to drift with the
magnetic field but ions cannot. In a fully-ionized plasma this occurs for
frequencies between the ion and electron cyclotron frequencies because of the
larger ion inertia. Typically this frequency range lies well above the
frequencies of interest (such as the dynamical frequency of the system under
consideration) and can be ignored. In a weakly-ionized medium, however, the
Hall effect arises through a different mechanism -- neutral collisions
preferentially decouple ions from the magnetic field. This typically occurs at
much lower frequencies and the Hall effect may play an important role in the
dynamics of weakly-ionised systems such as the Earth's ionosphere and
protoplanetary discs.
To clarify the relationship between these mechanisms we develop an
approximate single-fluid description of a partially ionized plasma that becomes
exact in the fully-ionized and weakly-ionized limits. Our treatment includes
the effects of ohmic, ambipolar, and Hall diffusion. We show that the Hall
effect is relevant to the dynamics of a partially ionized medium when the
dynamical frequency exceeds the ratio of ion to bulk mass density times the
ion-cyclotron frequency, i.e. the Hall frequency. The corresponding length
scale is inversely proportional to the ion to bulk mass density ratio as well
as to the ion-Hall beta parameter.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 09:44:55 GMT"
},
{
"version": "v2",
"created": "Sun, 9 Dec 2007 22:37:10 GMT"
},
{
"version": "v3",
"created": "Mon, 21 Jan 2008 08:01:51 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Pandey",
"B. P.",
""
],
[
"Wardle",
"Mark",
""
]
] |
0707.2689 | Tatsuro Yuge | Tatsuro Yuge, Akira Shimizu | Long-Time Behavior of Velocity Autocorrelation Function for Interacting
Particles in a Two-Dimensional Disordered System | 12 pages, 5 figures | null | 10.1143/JPSJ.76.093001 | null | cond-mat.stat-mech | null | The long-time behavior of the velocity autocorrelation function (VACF) is
investigated by the molecular dynamics simulation of a two-dimensional system
which has both a many-body interaction and a random potential. With
strengthening the random potential by increasing the density of impurities, a
crossover behavior of the VACF is observed from a positive tail, which is
proportional to t^{-1}, to a negative tail, proportional to -t^{-2}. The latter
tail exists even when the density of particles is the same order as the density
of impurities. The behavior of the VACF in a nonequilibrium steady state is
also studied. In the linear response regime the behavior is similar to that in
the equilibrium state, whereas it changes drastically in the nonlinear response
regime.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 09:56:09 GMT"
},
{
"version": "v2",
"created": "Fri, 25 Jan 2008 06:14:16 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Yuge",
"Tatsuro",
""
],
[
"Shimizu",
"Akira",
""
]
] |
0707.2690 | Roy Lacey | P Chung (Dept of Chemistry, SUNY Stony Brook, Stony Brook, NY, USA)
and P Danielewicz (National Superconducting Cyclotron Laboratory and
Department of Physics and Astronomy, Michigan State University, East Lansing,
MI, USA) (for The NA49 Collaboration) | Evidence for non-Gaussian tail in 3D pion emission source at the SPS | Proceedings, QM06, Beijing, China | J.Phys.G34:S1109-S1112,2007; Int.J.Mod.Phys.E16:2205-2209,2007 | 10.1088/0954-3899/34/8/S166 10.1142/S0218301307007696 | null | nucl-ex | null | The NA49 experiment at CERN SPS has acquired a huge data set of Pb+Pb events
over a broad range of energy and centrality during the last several years. This
high statistics data set, coupled with a state-of-the-art analysis technique,
allows for the first model-independent extraction and energy scan of 3D
emission sources for pion pairs at SPS energies. These 3D pion emission sources
provide new insights into the nature of a long-range source previously reported
by PHENIX at RHIC. The new results indicate that the pion source displays
significant non-Gaussian tails in the longitudinal direction at 40 and 158 AGeV
and in the outward direction at 158 AGeV.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 10:06:54 GMT"
}
] | 2019-08-17T00:00:00 | [
[
"Chung",
"P",
"",
"Dept of Chemistry, SUNY Stony Brook, Stony Brook, NY, USA"
],
[
"Danielewicz",
"P",
"",
"National Superconducting Cyclotron Laboratory and\n Department of Physics and Astronomy, Michigan State University, East Lansing,\n MI, USA"
]
] |
0707.2691 | Enrique P\'erez-Montero | Enrique Perez-Montero (LATT-OMP), Guillermo F. Hagele (UAM), Thierry
Contini (LATT-OMP), Angeles I. Diaz | Neon and Argon optical emission lines in ionized gaseous nebulae:
Implications and applications | 12 pages, 12 figures, accepted for publication in Monthly Notices of
the Royal Astronomical Society | null | 10.1111/j.1365-2966.2007.12213.x | null | astro-ph | null | In this work we present a study of the strong optical collisional emission
lines of Ne and Ar in an heterogeneous sample of ionized gaseous nebulae for
which it is possible to derive directly the electron temperature and hence the
chemical abundances of neon and argon. We calculate using a grid of
photoionization models new ionization correction factors for these two elements
and we study the behaviour of Ne/O and Ar/O abundance ratios with metallicity.
We find a constant value for Ne/O, while there seems to be some evidence for
the existence of negative radial gradients of Ar/O over the disks of some
nearby spirals. We study the relation between the intensities of the emission
lines of [NeIII] at 3869 \AA and [OIII] at 4959 \AA and 5007 \AA. This relation
can be used in empirical calibrations and diagnostic ratios extending their
applicability to bluer wavelengths and therefore to samples of objects at
higher redshifts. Finally, we propose a new diagnostic using [OII], [NeIII] and
Hdelta emission lines to derive metallicities for galaxies at high z.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 10:16:18 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Perez-Montero",
"Enrique",
"",
"LATT-OMP"
],
[
"Hagele",
"Guillermo F.",
"",
"UAM"
],
[
"Contini",
"Thierry",
"",
"LATT-OMP"
],
[
"Diaz",
"Angeles I.",
""
]
] |
0707.2692 | Mario Rodriguez-Meza | Jorge L. Cervantes-Cota, M. A. Rodriguez-Meza and Dario Nunez | Flat rotation curves using scalar-tensor theories | To appear in Journal of Physics: Conference Series: VII Mexican
School on Gravitation and Mathematical Physics. 26 November to 1 December
2006, Playa del Carmen, Quintana Roo, Mexico | J.Phys.Conf.Ser.91:012007,2007 | 10.1088/1742-6596/91/1/012007 | null | astro-ph | null | We computed flat rotation curves from scalar-tensor theories in their weak
field limit. Our model, by construction, fits a flat rotation profile for
velocities of stars. As a result, the form of the scalar field potential and DM
distribution in a galaxy are determined. By taking into account the constraints
for the fundamental parameters of the theory $(\lambda, \alpha)$, it is
possible to obtain analytical results for the density profiles. For positive
and negative values of $\alpha$, the DM matter profile is as cuspy as NFW's.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 14:26:37 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Cervantes-Cota",
"Jorge L.",
""
],
[
"Rodriguez-Meza",
"M. A.",
""
],
[
"Nunez",
"Dario",
""
]
] |
0707.2693 | Silvia Mateos | S. Mateos, X. Barcons, F. J. Carrera, M. J. Page, M. T. Ceballos, G.
Hasinger, A. C. Fabian | XMM-Newton observations of the Lockman Hole V: time variability of the
brightest AGN | 24 pages; 76 figures; 5 tables. Accepted for Publication in Astronomy
and Astrophysics | null | 10.1051/0004-6361:20077909 | null | astro-ph | null | This paper presents the results of a study of X-ray spectral and flux
variability on time scales from months to years, of the 123 brightest objects
(including 46 type-1 AGN and 28 type-2 AGN) detected with XMM-Newton in the
Lockman Hole field. We detected flux variability with a significance >3sigma in
~50% of the objects, including 68+-11% and 48+-15% among our samples of type-1
and type-2 AGN. However we found that the fraction of sources with best quality
light curves that exhibit flux variability on the time scales sampled by our
data is >80%, i.e the great majority of the AGN population may actually vary in
flux on long time scales. The mean relative intrinsic amplitude of flux
variability was found to be ~0.15 although with a large dispersion in measured
values, from ~0.1 to ~0.65. The flux variability properties of our samples of
AGN do not significantly depend on the redshift or X-ray luminosity of the
objects and seem to be similar for the two AGN types. Using a broad band X-ray
colour we found that the fraction of sources showing spectral variability with
a significance >3sigma is ~40% i.e. less common than flux variability. Spectral
variability was found to be more common in type-2 AGN than in type-1 AGN with a
significance >99%. This result is consistent with the fact that part of the
soft emission in type-2 AGN comes from scattered radiation, and this component
is expected to be much less variable than the hard component. The observed flux
and spectral variability properties of our objects cannot be explained as being
produced by variability of one spectral component alone, for example changes in
the continuum shape associated with changes in the mass accretion rate, or
variability in the amount of X-ray absorption. At least two spectral components
must vary in order to explain the X-ray variability of our objects.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 10:23:30 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Mateos",
"S.",
""
],
[
"Barcons",
"X.",
""
],
[
"Carrera",
"F. J.",
""
],
[
"Page",
"M. J.",
""
],
[
"Ceballos",
"M. T.",
""
],
[
"Hasinger",
"G.",
""
],
[
"Fabian",
"A. C.",
""
]
] |
0707.2694 | Dima Shepelyansky L | A.D.Chepelianskii, A.S.Pikovsky and D.L.Shepelyansky | Synchnonization, zero-resistance states and rotating Wigner crystal | 4 pages, 4 figs | Eur. Phys. J. B 60, 225-229 (2007) | 10.1140/epjb/e2007-00341-x | null | cond-mat.mes-hall nlin.CD | null | We show that rotational angles of electrons moving in two dimensions (2D) in
a perpendicular magnetic field can be synchronized by an external microwave
field which frequency is close to the Larmor frequency. The synchronization
eliminates collisions between electrons and thus creates a regime with zero
diffusion corresponding to the zero-resistance states observed in experiments
with high mobility 2D electron gas (2DEG). For long range Coulomb interactions
electrons form a rotating hexagonal Wigner crystal. Possible relevance of this
effect for planetary rings is discussed.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 11:48:12 GMT"
}
] | 2007-12-17T00:00:00 | [
[
"Chepelianskii",
"A. D.",
""
],
[
"Pikovsky",
"A. S.",
""
],
[
"Shepelyansky",
"D. L.",
""
]
] |
0707.2695 | Oriana Mansutti | Alessandro De Angelis (1), Oriana Mansutti (1), Marco Roncadelli (2)
((1) University of Udine and INFN Udine-Trieste, (2) University of Pavia and
INFN Pavia) | Axion-Like Particles, Cosmic Magnetic Fields and Gamma-Ray Astrophysics | 17 pages, 6 figures; accepted for publication in Physics Letters B.
Revised version | Phys.Lett.B659:847-855,2008 | 10.1016/j.physletb.2007.12.012 | null | astro-ph hep-ph | null | Axion-Like Particles (ALPs) are predicted by many extensions of the Standard
Model and give rise to characteristic dimming and polarization effects in a
light beam travelling in a magnetic field. In this Letter, we demonstrate that
photon-ALP mixing in cosmic magnetic fields produces an observable distortion
in the energy spectra of distant gamma-ray sources (like AGN) for ranges of the
ALP parameters allowed by all available constraints. The resulting effect is
expected to show up in the energy band 100 MeV - 100 GeV, and so it can be
serched with the upcoming GLAST mission.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 10:42:49 GMT"
},
{
"version": "v2",
"created": "Fri, 14 Dec 2007 12:26:24 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"De Angelis",
"Alessandro",
""
],
[
"Mansutti",
"Oriana",
""
],
[
"Roncadelli",
"Marco",
""
]
] |
0707.2696 | Alessandra Retico | D. Cascio, S.C. Cheran, A. Chincarini, G. De Nunzio, P. Delogu, M.E.
Fantacci, G. Gargano, I. Gori, G.L. Masala, A. Preite Martinez, A. Retico, M.
Santoro, C. Spinelli and T. Tarantino | Automated detection of lung nodules in low-dose computed tomography | 4 pages, 2 figures: Proceedings of the Computer Assisted Radiology
and Surgery, 21th International Congress and Exhibition, Berlin, Volume 2,
Supplement 1, June 2007, pp 357-359 | null | null | null | physics.med-ph | null | A computer-aided detection (CAD) system for the identification of pulmonary
nodules in low-dose multi-detector computed-tomography (CT) images has been
developed in the framework of the MAGIC-5 Italian project. One of the main
goals of this project is to build a distributed database of lung CT scans in
order to enable automated image analysis through a data and cpu GRID
infrastructure. The basic modules of our lung-CAD system, consisting in a 3D
dot-enhancement filter for nodule detection and a neural classifier for
false-positive finding reduction, are described. The system was designed and
tested for both internal and sub-pleural nodules. The database used in this
study consists of 17 low-dose CT scans reconstructed with thin slice thickness
(~300 slices/scan). The preliminary results are shown in terms of the FROC
analysis reporting a good sensitivity (85% range) for both internal and
sub-pleural nodules at an acceptable level of false positive findings (1-9
FP/scan); the sensitivity value remains very high (75% range) even at 1-6
FP/scan
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 10:34:56 GMT"
}
] | 2007-07-19T00:00:00 | [
[
"Cascio",
"D.",
""
],
[
"Cheran",
"S. C.",
""
],
[
"Chincarini",
"A.",
""
],
[
"De Nunzio",
"G.",
""
],
[
"Delogu",
"P.",
""
],
[
"Fantacci",
"M. E.",
""
],
[
"Gargano",
"G.",
""
],
[
"Gori",
"I.",
""
],
[
"Masala",
"G. L.",
""
],
[
"Martinez",
"A. Preite",
""
],
[
"Retico",
"A.",
""
],
[
"Santoro",
"M.",
""
],
[
"Spinelli",
"C.",
""
],
[
"Tarantino",
"T.",
""
]
] |
0707.2697 | Celine Peroux | Celine Peroux (1), Miroslava Dessauges-Zavadsky (2), Sandro D'Odorico
(1), Tae-Sun Kim (3) and Richard G. McMahon (4) ((1) ESO, Germany, (2)
Geneva, Switzerland, (3) Potsdam, Germany, (4) IoA, Cambridge, UK) | A Homogeneous Sample of Sub-DLAs IV: Global Metallicity Evolution | 30 figures, 24 tables. Accepted for publication in MNRAS | null | 10.1111/j.1365-2966.2007.12235.x | null | astro-ph | null | An accurate method to measure the abundance of high-redshift galaxies
consists in the observation of absorbers along the line of sight toward a
background quasar. Here, we present abundance measurements of 13 z>3 sub-Damped
Lyman-alpha Systems (quasar absorbers with HI column density 19 < log N(HI) <
20.3 cm^-2) based on the high resolution observations with VLT UVES
spectrograph. These observations more than double the metallicity information
for sub-DLAs previously available at z>3. This new data, combined with other
sub-DLA measurements from the literature, confirm the stronger metallicity
redshift evolution than for the classical Damped Lyman-alpha absorbers.
Besides, these observations are used to compute for the first time the fraction
of gas ionised from photo-ionisation modelling in a sample of sub-DLAs. Based
on these results, we calculate that sub-DLAs contribute no more than 6% of the
expected amount of metals at z~2.5. We therefore conclude that even if sub-DLAs
are found to be more metal-rich than classical DLAs, they are insufficient to
close the so-called ``missing metals problem''.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 10:58:12 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Peroux",
"Celine",
""
],
[
"Dessauges-Zavadsky",
"Miroslava",
""
],
[
"D'Odorico",
"Sandro",
""
],
[
"Kim",
"Tae-Sun",
""
],
[
"McMahon",
"Richard G.",
""
]
] |
0707.2698 | Elke Roediger | E. Roediger, M. Brueggen (Jacobs University Bremen) | Ram pressure stripping of disc galaxies orbiting in clusters. I. Mass
and radius of the remaining gas disc | 11 pages, 11 figures, accepted by MNRAS, high resolution pdf version
available at
http://www.faculty.iu-bremen.de/eroediger/PAPERS/eroediger_crossing.pdf | null | 10.1111/j.1365-2966.2007.12241.x | null | astro-ph | null | We present the first 3D hydrodynamical simulations of ram pressure stripping
of a disc galaxy orbiting in a galaxy cluster. Along the orbit, the ram
pressure that this galaxy experiences varies with time. In this paper, we focus
on the evolution of the radius and mass of the remaining gas disc and compare
it with the classical analytical estimate proposed by Gunn & Gott 1972. We find
that this simple estimate works well in predicting the evolution of the radius
of the remaining gas disc. Only if the ram pressure increases faster than the
stripping timescale, the disc radius remains larger than predicted. However,
orbits with such short ram pressure peaks are unlikely to occur in other than
compact clusters. Unlike the radius evolution, the mass loss history for the
galaxy is not accurately described by the analytical estimate. Generally, in
the simulations the galaxy loses its gas more slowly than predicted.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 11:10:10 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Roediger",
"E.",
"",
"Jacobs University Bremen"
],
[
"Brueggen",
"M.",
"",
"Jacobs University Bremen"
]
] |
0707.2699 | Diego Trancanelli | Nadav Drukker, Simone Giombi, Riccardo Ricci, Diego Trancanelli | Wilson loops: From four-dimensional SYM to two-dimensional YM | 9 pages, LaTeX | Phys.Rev.D77:047901,2008 | 10.1103/PhysRevD.77.047901 | HU-EP-07/23, YITP-SB-07-23, Imperial/TP/07/RR/03 | hep-th | null | In this note we study supersymmetric Wilson loops restricted to an S^2
submanifold of four-dimensional space in N=4 super Yang-Mills. We provide
evidence from both perturbation theory and the AdS dual that those loops are
equal to the analogous observables in two-dimensional Yang-Mills on S^2
(excluding non-perturbative contributions). This relates a subsector of N=4 SYM
to a low-dimensional soluble model and also suggests that this subsector of N
=4 SYM is invariant under area preserving diffeomorphisms.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 11:27:35 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Drukker",
"Nadav",
""
],
[
"Giombi",
"Simone",
""
],
[
"Ricci",
"Riccardo",
""
],
[
"Trancanelli",
"Diego",
""
]
] |
0707.2700 | Alexandr Korchin | S.A. Ivashyn, A.Yu. Korchin | Radiative decays with light scalar mesons and singlet-octet mixing in
ChPT | 18 pages, 8 figures; misprints in text and tables corrected,
discussion extended, references added; version accepted for publication in
Eur.Phys.J. C | Eur.Phys.J.C54:89-106,2008 | 10.1140/epjc/s10052-007-0496-z | null | hep-ph | null | We study different types of radiative decays involving f0(980) and a0(980)
mesons within a unified ChPT-based approach at one-loop level. Light scalar
resonances which are seen in pi pi, pi eta, K K-bar channels of phi(1020)
radiative decays and in J/psi decays are responsible for key questions of
low-energy dynamics in the strong interaction sector, and decays phi(1020) ->
gamma a0(980), phi(1020) -> gamma f0(980), a0(980) -> gamma gamma, f0(980) ->
gamma gamma are of interest for current experimental programs in Juelich,
Frascati and Novosibirsk. From theoretical point of view it is important to
verify whether light scalar mesons are members of some flavor octet or nonet.
We find a value of mixing angle dictated by consistency with experiment and
coupling structures of ChPT Lagrangian. Decay widths f0(980)/a0(980) -> gamma
rho(770)/omega(782), which are not studied experimentally yet, are predicted.
We also obtain several relations between widths, which hold independently of
coupling constants and represent a fingerprint of the model.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 11:21:34 GMT"
},
{
"version": "v2",
"created": "Thu, 2 Aug 2007 10:48:22 GMT"
},
{
"version": "v3",
"created": "Wed, 28 Nov 2007 09:40:17 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Ivashyn",
"S. A.",
""
],
[
"Korchin",
"A. Yu.",
""
]
] |
0707.2701 | Gernot Schaller | Gernot Schaller | A fixed point iteration for computing the matrix logarithm | 4 pages, 3 figures, comments welcome | null | null | null | cs.NA cs.DS | null | In various areas of applied numerics, the problem of calculating the
logarithm of a matrix A emerges. Since series expansions of the logarithm
usually do not converge well for matrices far away from the identity, the
standard numerical method calculates successive square roots. In this article,
a new algorithm is presented that relies on the computation of successive
matrix exponentials. Convergence of the method is demonstrated for a large
class of initial matrices and favorable choices of the initial matrix are
discussed.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 11:04:27 GMT"
}
] | 2007-07-19T00:00:00 | [
[
"Schaller",
"Gernot",
""
]
] |
0707.2702 | Martin Haas F. | Martin Haas, Ralf Siebenmorgen, Eric Pantin, Hannes Horst, Alain
Smette, Hans-Ulrich Kaufl, Pierre-Olivier Lagage, Rolf Chini | VISIR/VLT mid-infrared imaging of Seyfert nuclei: Nuclear dust emission
and the Seyfert-2 dichotomy | 11 pages, 6 figures, accepted by A&A | null | 10.1051/0004-6361:20077520 | null | astro-ph | null | Half of the Seyfert-2 galaxies escaped detection of broad lines in their
polarised spectra observed so far. Some authors have suspected that these
non-HBLRs contain real Sy2 nuclei without intrinsic broad line region hidden
behind a dust torus. If this were true, then their nuclear structure would
fundamentally differ from that of Sy2s with polarised broad lines: in
particular, they would not be explained by orientation-based AGN unification.
Further arguments for two physically different Sy2 populations have been
derived from the warm and cool IRAS F25/F60 ratios. These ratios, however,
refer to the entire host galaxies and are unsuitable to conclusively establish
the absence of a nuclear dust torus. Instead, a study of the Seyfert-2
dichotomy should be performed on the basis of nuclear properties only. Here we
present the first comparison between [OIII] 5007A and mid-infrared imaging at
matching spatial resolution. Exploring the Seyfert-2 dichotomy we find that the
distributions of nuclear mid-infrared/[OIII] luminosity ratios are
indistinguishable for Sy1s and Sy2s with and without detected polarised broad
lines and irrespective of having warm or cool IRAS F25/F60 ratios. We find no
evidence for the existence of a population of real Sy2s with a deficit of
nuclear dust emission. Our results suggest 1) that all Seyfert nuclei possess
the same physical structure including the putative dust torus and 2) that the
cool IRAS colours are caused by a low contrast of AGN to host galaxy. Then the
Seyfert-2 dichotomy is explained in part by unification of non-HBLRs with
narrow-line Sy1s and to a larger rate by observational biases caused by a low
AGN/host contrast and/or an unfavourable scattering geometry.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 11:17:50 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Haas",
"Martin",
""
],
[
"Siebenmorgen",
"Ralf",
""
],
[
"Pantin",
"Eric",
""
],
[
"Horst",
"Hannes",
""
],
[
"Smette",
"Alain",
""
],
[
"Kaufl",
"Hans-Ulrich",
""
],
[
"Lagage",
"Pierre-Olivier",
""
],
[
"Chini",
"Rolf",
""
]
] |
0707.2703 | Taro Nakajima | T. Nakajima, S. Mitsuda, S. Kanetsuki, K. Tanaka, K. Fujii, N. Terada,
M. Soda, M. Matsuura, K. Hirota | Electric Polarization Induced by a Proper Helical Magnetic Ordering in a
Delafossite Multiferroic CuFe1-xAlxO2 | 4 pages, 4 figures | Phys. Rev. B 77, 052401 (2008) | 10.1103/PhysRevB.77.052401 | null | cond-mat.str-el | null | Multiferroic CuFe1-xAlxO2 (x=0.02) exhibits a ferroelectric ordering
accompanied by a proper helical magnetic ordering below T=7K under zero
magnetic field. By polarized neutron diffraction and pyroelectric measurements,
we have revealed a one-to-one correspondence between the spin helicity and the
direction of the spontaneous electric polarization. This result indicates that
the spin helicity of the proper helical magnetic ordering is essential for the
ferroelectricity in CuFe1-xAlxO2. The induction of the electric polarization by
the proper helical magnetic ordering is, however, cannot be explained by the
Katsura-Nagaosa-Balatsky model, which successfully explains the
ferroelectricity in the recently explored ferroelectric helimagnets, such as
TbMnO3. We thus conclude that CuFe1-xAlxO2 is a new class of magnetic
ferroelectrics.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 11:33:17 GMT"
}
] | 2008-03-31T00:00:00 | [
[
"Nakajima",
"T.",
""
],
[
"Mitsuda",
"S.",
""
],
[
"Kanetsuki",
"S.",
""
],
[
"Tanaka",
"K.",
""
],
[
"Fujii",
"K.",
""
],
[
"Terada",
"N.",
""
],
[
"Soda",
"M.",
""
],
[
"Matsuura",
"M.",
""
],
[
"Hirota",
"K.",
""
]
] |
0707.2704 | Koichi Kusakabe Dr | K. Kusakabe | Determination of the Mott insulating transition by the multi-reference
density functional theory | 5 pages, 1 figure, to appear in J. Phys. Condens. Matter | null | 10.1088/0953-8984/19/36/365229 | null | cond-mat.str-el | null | It is shown that a momentum-boost technique applied to the extended Kohn-Sham
scheme enables the computational determination of the Mott insulating
transition. Self-consistent solutions are given for correlated electron systems
by the first-principles calculation defined by the multi-reference density
functional theory, in which the effective short-range interaction can be
determined by the fluctuation reference method. An extension of the Harriman
construction is made for the twisted boundary condition in order to define the
momentum-boost technique in the first-principles manner. For an effectively
half-filled-band system, the momentum-boost method tells that the period of a
metallic ground state by the LDA calculation is shortened to the least period
of the insulating phase, indicating occurrence of the Mott insulating
transition.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 11:49:11 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Kusakabe",
"K.",
""
]
] |
0707.2705 | Koichi Kusakabe Dr | Koichi Kusakabe, Naoshi Suzuki, Shusuke Yamanaka and Kizashi Yamaguchi | A self-consistent first-principles calculation scheme for correlated
electron systems | 23 pages, 8 figures, to appear in J. Phys. Condens. Matter | null | 10.1088/0953-8984/19/44/445009 | null | cond-mat.str-el | null | A self-consistent calculation scheme for correlated electron systems is
created based on the density-functional theory (DFT). Our scheme is a
multi-reference DFT (MR-DFT) calculation in which the electron charge density
is reproduced by an auxiliary interacting Fermion system. A short-range
Hubbard-type interaction is introduced by a rigorous manner with a residual
term for the exchange-correlation energy. The Hubbard term is determined
uniquely by referencing the density fluctuation at a selected localized
orbital. This strategy to obtain an extension of the Kohn-Sham scheme provides
a self-consistent electronic structure calculation for the materials design.
Introducing an approximation for the residual exchange-correlation energy
functional, we have the LDA+U energy functional. Practical self-consistent
calculations are exemplified by simulations of Hydrogen systems, i.e. a
molecule and a periodic one-dimensional array, which is a proof of existence of
the interaction strength U as a continuous function of the local fluctuation
and structural parameters of the system.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 11:56:05 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Kusakabe",
"Koichi",
""
],
[
"Suzuki",
"Naoshi",
""
],
[
"Yamanaka",
"Shusuke",
""
],
[
"Yamaguchi",
"Kizashi",
""
]
] |
0707.2706 | Vladimir Kanovei | Vladimir Kanovei | A weak dichotomy below E_1 \times E_3 | null | Topology and its applications, 2010, 157, 8, pp. 1465-1478 | 10.1016/j.topol.2009.03.052 | null | math.LO | null | If E is an equivalence relation Borel reducible to E_1 \times E_3 then either
E is Borel reducible to the equality of countable sets of reals or E_1 is Borel
reducible to E. The "either" case admits further strengthening.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 14:23:25 GMT"
}
] | 2018-08-16T00:00:00 | [
[
"Kanovei",
"Vladimir",
""
]
] |
0707.2707 | Mate Matolcsi | Katalin Gyarmati, Imre Z. Ruzsa, Mate Matolcsi | A superadditivity and submultiplicativity property for cardinalities of
sumsets | 9 pages | null | null | null | math.CO math.AC | null | For finite sets of integers $A_1, A_2 ... A_n$ we study the cardinality of
the $n$-fold sumset $A_1+...
+A_n$ compared to those of $n-1$-fold sumsets $A_1+...
+A_{i-1}+A_{i+1}+... A_n$. We prove a superadditivity and a
submultiplicativity property for these quantities. We also examine the case
when the addition of elements is restricted to an addition graph between the
sets.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 12:05:36 GMT"
}
] | 2007-07-19T00:00:00 | [
[
"Gyarmati",
"Katalin",
""
],
[
"Ruzsa",
"Imre Z.",
""
],
[
"Matolcsi",
"Mate",
""
]
] |
0707.2708 | Laszlo Feher | L. Feher, B.G. Pusztai | On the self-adjointness of certain reduced Laplace-Beltrami operators | 9 pages, minor changes, updated references in v2 | Rep. Math. Phys. 61 (2008) 163-170 | 10.1016/S0034-4877(08)00012-8 | null | math-ph math.MP nlin.SI quant-ph | null | The self-adjointness of the reduced Hamiltonian operators arising from the
Laplace-Beltrami operator of a complete Riemannian manifold through quantum
Hamiltonian reduction based on a compact isometry group is studied. A simple
sufficient condition is provided that guarantees the inheritance of essential
self-adjointness onto a certain class of restricted operators and allows us to
conclude the self-adjointness of the reduced Laplace-Beltrami operators in a
concise way. As a consequence, the self-adjointness of spin Calogero-Sutherland
type reductions of `free' Hamiltonians under polar actions of compact Lie
groups follows immediately.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 12:08:54 GMT"
},
{
"version": "v2",
"created": "Fri, 30 Nov 2007 13:59:20 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Feher",
"L.",
""
],
[
"Pusztai",
"B. G.",
""
]
] |
0707.2709 | Charles Doiron | C. B. Doiron, B. Trauzettel and C. Bruder | Measuring the Momentum of a Nanomechanical Oscillator through the Use of
Two Tunnel Junctions | New title. Published version | Phys. Rev. Lett. 100, 027202 (2008) | 10.1103/PhysRevLett.100.027202 | null | cond-mat.mes-hall | null | We propose a way to measure the momentum p of a nanomechanical oscillator.
The p-detector is based on two tunnel junctions in a Aharonov-Bohm-type setup.
One of the tunneling amplitudes depends on the motion of the oscillator, the
other one not. Although the coupling between the detector and the oscillator is
assumed to be linear in the position x of the oscillator, it turns out that the
finite-frequency noise output of the detector will in general contain a term
proportional to the momentum spectrum of the oscillator. This is a true quantum
phenomenon, which can be realized in practice if the phase of the tunneling
amplitude of the detector is tuned by the Aharonov-Bohm flux Phi to a
p-sensitive value.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 14:10:13 GMT"
},
{
"version": "v2",
"created": "Wed, 16 Jan 2008 10:15:23 GMT"
}
] | 2008-01-16T00:00:00 | [
[
"Doiron",
"C. B.",
""
],
[
"Trauzettel",
"B.",
""
],
[
"Bruder",
"C.",
""
]
] |
0707.2710 | Ramij Rahaman | Sujit K. Choudhary, Guruprasad Kar, Samir Kunkri, Ramij Rahaman and
Anirban Roy | Local cloning of genuine entangled states of three qubit | 4 pages | Physical Review A 76, 062312 (2007) | 10.1103/PhysRevA.76.062312 | null | quant-ph | null | We discuss (im)possibility of the exact cloning of orthogonal but genuinely
entangled three qubit states aided with entangled ancila under local operation
and classical communication. Whereas any two orthogonal GHZ states taken from
the canonical GHZ basis, can be cloned with the help of a known GHZ state,
surprisingly we find that no two W states can be cloned by using any known
three qubit (possibly entangled) state as blank copy.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 12:16:53 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Choudhary",
"Sujit K.",
""
],
[
"Kar",
"Guruprasad",
""
],
[
"Kunkri",
"Samir",
""
],
[
"Rahaman",
"Ramij",
""
],
[
"Roy",
"Anirban",
""
]
] |
0707.2711 | Thomas Heinzel | C.C. Bof Bufon and T. Heinzel | Transport properties of chemically synthesized polypyrrole thin films | 6 pages, 5 figures | Phys. Rev. B 76, 245206 (2007) | 10.1103/PhysRevB.76.245206 | null | cond-mat.dis-nn cond-mat.mtrl-sci | null | The electronic transport in polypyrrole thin films synthesized chemically
from the vapor phase is studied as a function of temperature as well as of
electric and magnetic fields. We find distinct differences in comparison to the
behavior of both polypyrrole films prepared by electrochemical growth as well
as of the bulk films obtained from conventional chemical synthesis. For small
electric fields F, a transition from Efros-Shklovskii variable range hopping to
Arrhenius activated transport is observed at 30 K. High electric fields induce
short range hopping. The characteristic hopping distance is found to be
proportional to F^(-1/2). The magnetoresistance R(B) is independent of F below
a critical magnetic field, above which F counteracts the magnetic field induced
localization.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 12:20:00 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Bufon",
"C. C. Bof",
""
],
[
"Heinzel",
"T.",
""
]
] |
0707.2712 | Radu Tatar | Radu Tatar and Ben Wetenhall | Metastable Vacua and Complex Deformations | 22 Pages, Latex | Phys.Rev.D76:126011,2007 | 10.1103/PhysRevD.76.126011 | LTH/750 | hep-th | null | We use the non-normalizable complex deformations to describe the stringy
realizations of the metastable vacua in N = 1, SU(N_c) SUSY theories with N_f >
N_c massive fundamental flavors. The consideration of the non-normalizable
deformations requires a modified Toric duality. The new approach considers the
tachyon condensation between pairs of wrapped D5 branes and anti D5 branes and
the resulting mixing between some cycles in the geometry. We enlarge the class
of metastable vacua to the case of branes-antibranes wrapped on cycles of
deformed A_n singularities.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 12:27:35 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Tatar",
"Radu",
""
],
[
"Wetenhall",
"Ben",
""
]
] |
0707.2713 | Singh N.Nimai | N. Nimai Singh, H. Zeen Devi and Mahadev Patgiri | Normal versus inverted hierarchical models within $\mu-\tau$ symmetry | 37 pages,5 figures, title changed, one section on leptogenesis added,
some portions deleted and references added | null | null | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We make a theoretical attempt to compare the predictions from normal and
inverted hierarchical models, within the framework of $\mu-\tau$ symmetry. We
consider three major theoretical issues in a self consistent ways, viz.,
predictions on neutrino mass and mixing parameters, stability under RG analysis
in MSSM, and baryogenesis through leptogenesis. We further extend our earlier
works on parametrisation of neutrino mass matrices using only two parameters,
in addition to an overall mass scale $m_0$, and the ratio of these two
parameters fixes the value of solar mixing angle. Such parametrisation though
phenomenological gives a firm handle on the analysis of the mass matrices and
predicts lower values of solar mixing angle in the range
$\tan^2\theta_{12}=0.50-0.35$.We check the stability of the model under
radiative corrections in MSSM for large $\tan\beta\sim 58-60$ region and
observe that the evolution of $\bigtriangleup m^2_{21}$ with energy scale, is
highly dependent on the input high scale value of solar mixing angle. Solar
angle predicted by tri-bimaximal mixings and also values lower than this, do
not lead to stability of the model. Similarly, the evolution of the atmospheric
mixing angle with energy scale at large $\tan\beta$ values, shows sharp
decrease for the case with non-zero value of m_3. We apply these mass matrices
to estimate the baryon asymmetry of the universe in a self consistent way and
find that normal hierarchical model leads to the best result. Considering all
these three pieces of theoretical investigations, we may conclude that normal
hierarchical model is more favourable in nature.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 12:29:59 GMT"
},
{
"version": "v2",
"created": "Mon, 23 Jul 2007 13:15:15 GMT"
},
{
"version": "v3",
"created": "Tue, 15 Jul 2008 13:39:54 GMT"
}
] | 2008-07-15T00:00:00 | [
[
"Singh",
"N. Nimai",
""
],
[
"Devi",
"H. Zeen",
""
],
[
"Patgiri",
"Mahadev",
""
]
] |
0707.2714 | Heinz Horner | Heinz Horner | Time Dependent Local Field Distribution and Metastable States in the
SK-Spin-Glass | Minor changes and journal reference added. 10 pages 6 figures | null | 10.1140/epjb/e2008-00017-1 | null | cond-mat.dis-nn cond-mat.stat-mech | null | Different sets of metastable states can be reached in glassy systems below
some transition temperature depending on initial conditions and details of the
dynamics. This is investigated for the Sherrington-Kirkpatrick spin glass model
with long ranged interactions. In particular, the time dependent local field
distribution and energy are calculated for zero temperature. This is done for a
system quenched to zero temperature, slow cooling or simulated annealing, a
greedy algorithm and repeated tapping. Results are obtained from Monte-Carlo
simulations and a Master-Fokker-Planck approach. A comparison with replica
symmetry broken theory, evaluated in high orders, shows that the energies
obtained via dynamics are higher than the ground state energy of replica
theory. Tapping and simulated annealing yield on the other hand results which
are very close to the ground state energy. The local field distribution tends
to zero for small fields. This is in contrast to the Edwards flat measure
hypothesis. The distribution of energies obtained for different tapping
strengths does again not follow the canonical form proposed by Edwards.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 12:43:15 GMT"
},
{
"version": "v2",
"created": "Wed, 22 Aug 2007 13:36:54 GMT"
},
{
"version": "v3",
"created": "Mon, 10 Dec 2007 22:17:44 GMT"
}
] | 2015-03-13T00:00:00 | [
[
"Horner",
"Heinz",
""
]
] |
0707.2715 | Axel Pelster | Konstantin Glaum, Hagen Kleinert, Axel Pelster | Condensation of Ideal Bose Gas Confined in a Box Within a Canonical
Ensemble | 18 pages, 8 figures | Physical Review A 76, 063604 (2007) | 10.1103/PhysRevA.76.063604 | null | cond-mat.stat-mech | null | We set up recursion relations for the partition function and the ground-state
occupancy for a fixed number of non-interacting bosons confined in a square box
potential and determine the temperature dependence of the specific heat and the
particle number in the ground state. A proper semiclassical treatment is set up
which yields the correct small-T-behavior in contrast to an earlier theory in
Feynman's textbook on Statistical Mechanics, in which the special role of the
ground state was ignored. The results are compared with an exact quantum
mechanical treatment. Furthermore, we derive the finite-size effect of the
system.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 12:43:57 GMT"
},
{
"version": "v2",
"created": "Wed, 12 Dec 2007 11:48:40 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Glaum",
"Konstantin",
""
],
[
"Kleinert",
"Hagen",
""
],
[
"Pelster",
"Axel",
""
]
] |
0707.2716 | David Jess | D. B. Jess, A. Andic, M. Mathioudakis, D. S. Bloomfield and F. P.
Keenan | High-Frequency Oscillations in a Solar Active Region observed with the
Rapid Dual Imager | 9 pages, 9 figures | null | 10.1051/0004-6361:20077142 | null | astro-ph | null | High-cadence, synchronized, multiwavelength optical observations of a solar
active region (NOAA 10794) are presented. The data were obtained with the Dunn
Solar Telescope at the National Solar Observatory/Sacramento Peak using a newly
developed camera system : the Rapid Dual Imager. Wavelet analysis is undertaken
to search for intensity related oscillatory signatures, and periodicities
ranging from 20 to 370 s are found with significance levels exceeding 95%.
Observations in the H-alpha blue wing show more penumbral oscillatory phenomena
when compared to simultaneous G-band observations. The H-alpha oscillations are
interpreted as the signatures of plasma motions with a mean velocity of 20
km/s. The strong oscillatory power over H-alpha blue-wing and G-band penumbral
bright grains is an indication of the Evershed flow with frequencies higher
than previously reported.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 13:15:16 GMT"
},
{
"version": "v2",
"created": "Mon, 1 Oct 2007 12:34:13 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Jess",
"D. B.",
""
],
[
"Andic",
"A.",
""
],
[
"Mathioudakis",
"M.",
""
],
[
"Bloomfield",
"D. S.",
""
],
[
"Keenan",
"F. P.",
""
]
] |
0707.2717 | Bernard de Wit | Mathijs de Vroome and Bernard de Wit | Lagrangians with electric and magnetic charges of N=2 supersymmetric
gauge theories | 34 pages, LaTex | JHEP 0708:064,2007 | 10.1088/1126-6708/2007/08/064 | ITP-UU-07/35; SPIN-07/24 | hep-th | null | General Lagrangians are constructed for N=2 supersymmetric gauge theories in
four space-time dimensions involving gauge groups with (non-abelian) electric
and magnetic charges. The charges induce a scalar potential, which, when the
charges are regarded as spurionic quantities, is invariant under
electric/magnetic duality. The resulting theories are especially relevant for
supergravity, but details of the extension to local supersymmetry will be
discussed elsewhere. The results include the coupling to hypermultiplets.
Without the latter, it is demonstrated how an off-shell representation can be
constructed based on vector and tensor supermultiplets.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 12:53:22 GMT"
}
] | 2009-04-30T00:00:00 | [
[
"de Vroome",
"Mathijs",
""
],
[
"de Wit",
"Bernard",
""
]
] |
0707.2718 | Damien Chablat | Damien Chablat (IRCCyN) | Animation of virtual mannequins, robot-like simulation or motion
captures | null | 3D Modelling Conferences - 3D Human (06/2006) 1-12 | null | null | cs.RO | null | In order to optimize the costs and time of design of the new products while
improving their quality, concurrent engineering is based on the digital model
of these products, the numerical model. However, in order to be able to avoid
definitively physical model, old support of the design, without loss of
information, new tools must be available. Especially, a tool making it possible
to check simply and quickly the maintainability of complex mechanical sets
using the numerical model is necessary. Since one decade, our team works on the
creation of tool for the generation and the analysis of trajectories of virtual
mannequins. The simulation of human tasks can be carried out either by
robot-like simulation or by simulation by motion capture. This paper presents
some results on the both two methods. The first method is based on a
multi-agent system and on a digital mock-up technology, to assess an efficient
path planner for a manikin or a robot for access and visibility task taking
into account ergonomic constraints or joint and mechanical limits. In order to
solve this problem, the human operator is integrated in the process
optimization to contribute to a global perception of the environment. This
operator cooperates, in real-time, with several automatic local elementary
agents. In the case of the second approach, we worked with the CEA and EADS/CCR
to solve the constraints related to the evolution of human virtual in its
environment on the basis of data resulting from motion capture system. An
approach using of the virtual guides was developed to allow to the user the
realization of precise trajectory in absence of force feedback. The result of
this work validates solutions through the digital mock-up; it can be applied to
simulate maintenability and mountability tasks.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 12:59:15 GMT"
}
] | 2007-07-19T00:00:00 | [
[
"Chablat",
"Damien",
"",
"IRCCyN"
]
] |
0707.2719 | Sang-Jin Sin | Sang-Jin Sin | Bulk Filling Branes and the Baryon Density in AdS/QCD with gravity
back-reaction | 17 pages 3x2 figures, v2: references added;v3 published version,
title change and reference added | JHEP 0710:078,2007 | 10.1088/1126-6708/2007/10/078 | null | hep-th | null | We consider the gravity back reaction on the metric due to the baryon density
in effective ads/qcd model by reconsidering the role of the charged AdS black
hole. Previously it has been known that the U(1) charge is dual to the
R-charge. Here we point out that if we consider the case where $AdS_5$ is
completely filled with $N_f$ flavor branes, the gravity back reaction produces
charged AdS black hole where the effect of charge on the metric is proportional
to $N_f/N_c$. As a consequence, phase diagram changes qualitatively if we allow
$N_f/N_c$ finite: it closes at the finite density unlike the probe brane
embedding approach.
Another issue we discuss here is the question whether there is any chemical
potential dependence in the confining phase. We consider this problem in the
hard wall model with baryon charge. We conclude that there is a non-trivial
dependence on the chemical potential in this case also.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 12:59:47 GMT"
},
{
"version": "v2",
"created": "Wed, 25 Jul 2007 03:49:37 GMT"
},
{
"version": "v3",
"created": "Tue, 23 Oct 2007 11:10:51 GMT"
}
] | 2009-04-17T00:00:00 | [
[
"Sin",
"Sang-Jin",
""
]
] |
0707.2720 | Guihua Chen | Guihua Chen, Weiliang Wang, Jie Peng, Chunshan He, Shaozhi Deng,
Ningsheng Xu, Zhibing Li | Screening effects on field emission from arrays of (5,5) carbon
nanotubes: Quantum-mechanical simulation | null | Phys. Rev. B 76, 195412 (2007) | 10.1103/PhysRevB.76.195412 | null | cond-mat.mtrl-sci cond-mat.mes-hall | null | The simulation of field electron emission from arrays of micrometer-long
open-ended (5, 5) carbon nanotubes is performed in the framework of quantum
theory of many electrons. It is found that the applied external field is
strongly screened when the spacing distance is shorter than the length of the
carbon nanotubes. The optimal spacing distance is two to three times of the
nanotube length, slightly depending on the applied external fields. The
electric screening can be described by a factor that is a exponential function
of the ratio of the spacing distance to the length of the carbon nanotubes. For
a given length, the field enhancement factor decreases sharply as the screening
factor larger than 0.05. The simulation implies that the thickness of the array
should be larger than a value but it does not help the emission much by
increasing the thickness a great deal.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 13:22:49 GMT"
},
{
"version": "v2",
"created": "Wed, 28 Nov 2007 02:59:09 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Chen",
"Guihua",
""
],
[
"Wang",
"Weiliang",
""
],
[
"Peng",
"Jie",
""
],
[
"He",
"Chunshan",
""
],
[
"Deng",
"Shaozhi",
""
],
[
"Xu",
"Ningsheng",
""
],
[
"Li",
"Zhibing",
""
]
] |
0707.2721 | Damien Chablat | Qinqin Zhang (IRCCyN, DIE), Damien Chablat (IRCCyN), Fouad Bennis
(IRCCyN), Wei Zhang (DIE) | A Framework to Illustrate Kinematic Behavior of Mechanisms by Haptic
Feedback | null | Proceedings of Virtual Concept (25/11/2006) 1-6 | null | null | cs.RO | null | The kinematic properties of mechanisms are well known by the researchers and
teachers. The theory based on the study of Jacobian matrices allows us to
explain, for example, the singular configuration. However, in many cases, the
physical sense of such properties is difficult to explain to students. The aim
of this article is to use haptic feedback to render to the user the
signification of different kinematic indices. The framework uses a Phantom Omni
and a serial and parallel mechanism with two degrees of freedom. The
end-effector of both mechanisms can be moved either by classical mouse, or
Phantom Omni with or without feedback.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 13:02:29 GMT"
}
] | 2007-07-19T00:00:00 | [
[
"Zhang",
"Qinqin",
"",
"IRCCyN, DIE"
],
[
"Chablat",
"Damien",
"",
"IRCCyN"
],
[
"Bennis",
"Fouad",
"",
"IRCCyN"
],
[
"Zhang",
"Wei",
"",
"DIE"
]
] |
0707.2722 | Axel Gruenrock | Axel Gruenrock, Mahendra Panthee, Jorge Drumond Silva | A remark on global well-posedness below L^2 for the gKdV-3 equation | 6 pages | null | null | null | math.AP | null | The I-method in its first version as developed by Colliander et al. is
applied to prove that the Cauchy-problem for the generalised Korteweg-de Vries
equation of order three (gKdV-3) is globally well-posed for large real-valued
data in the Sobolev space H^s, provided s>-1/42.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 13:30:10 GMT"
}
] | 2007-07-19T00:00:00 | [
[
"Gruenrock",
"Axel",
""
],
[
"Panthee",
"Mahendra",
""
],
[
"Silva",
"Jorge Drumond",
""
]
] |
0707.2723 | Benjamin Jourdain | Benjamin Jourdain (CERMICS), Sylvie M\'el\'eard (CMAP), Wojbor
Woyczynski | Nonlinear SDEs driven by L\'evy processes and related PDEs | null | null | null | null | math.PR | null | In this paper we study general nonlinear stochastic differential equations,
where the usual Brownian motion is replaced by a L\'evy process. We also
suppose that the coefficient multiplying the increments of this process is
merely Lipschitz continuous and not necessarily linear in the time-marginals of
the solution as is the case in the classical McKean-Vlasov model. We first
study existence, uniqueness and particle approximations for these stochastic
differential equations. When the driving process is a pure jump L\'evy process
with a smooth but unbounded L\'evy measure, we develop a stochastic calculus of
variations to prove that the time-marginals of the solutions are absolutely
continuous with respect to the Lebesgue measure. In the case of a symmetric
stable driving process, we deduce the existence of a function solution to a
nonlinear integro-differential equation involving the fractional Laplacian.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 13:46:42 GMT"
}
] | 2007-07-19T00:00:00 | [
[
"Jourdain",
"Benjamin",
"",
"CERMICS"
],
[
"Méléard",
"Sylvie",
"",
"CMAP"
],
[
"Woyczynski",
"Wojbor",
""
]
] |
0707.2724 | Katarzyna Helena Wichmann | Katarzyna Wichmann (on behalf of the H1 and ZEUS Collaborations) | Recent Results from HERA Experiments | proceedings for the Hadron Collider Physics 2006 conference (HCP2006) | null | null | null | hep-ex | null | Recent results from HERA are presented. The main reviewed subjects are
polarized DIS cross sections, parton density determination, diffractive PDFs,
multi-jet production and searches for physics beyond the Standard Model.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 14:10:31 GMT"
}
] | 2007-07-19T00:00:00 | [
[
"Wichmann",
"Katarzyna",
"",
"on behalf of the H1 and ZEUS Collaborations"
]
] |
0707.2725 | Krzysztof Gawedzki | Raphael Chetrite and Krzysztof Gawedzki | Fluctuation Relations for Diffusion Processes | 38 pages | null | 10.1007/s00220-008-0502-9 | null | math-ph cond-mat.stat-mech math.MP | null | The paper presents a unified approach to different fluctuation relations for
classical nonequilibrium dynamics described by diffusion processes. Such
relations compare the statistics of fluctuations of the entropy production or
work in the original process to the similar statistics in the time-reversed
process. The origin of a variety of fluctuation relations is traced to the use
of different time reversals. It is also shown how the application of the
presented approach to the tangent process describing the joint evolution of
infinitesimally close trajectories of the original process leads to a
multiplicative extension of the fluctuation relations.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 14:13:29 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Chetrite",
"Raphael",
""
],
[
"Gawedzki",
"Krzysztof",
""
]
] |
0707.2726 | Marco Valerio Battisti | Marco Valerio Battisti and Giovanni Montani | Quantum Dynamics of the Taub Universe in a Generalized Uncertainty
Principle framework | 10 pages, 4 figures; v2: section added, to appear on PRD | Phys.Rev.D77:023518,2008 | 10.1103/PhysRevD.77.023518 | null | gr-qc hep-th | null | The implications of a Generalized Uncertainty Principle on the Taub
cosmological model are investigated. The model is studied in the ADM reduction
of the dynamics and therefore a time variable is ruled out. Such a variable is
quantized in a canonical way and the only physical degree of freedom of the
system (related to the Universe anisotropy) is quantized by means of a modified
Heisenberg algebra. The analysis is performed at both classical and quantum
level. In particular, at quantum level, the motion of wave packets is
investigated. The two main results obtained are as follows. i) The classical
singularity is probabilistically suppressed. The Universe exhibits a stationary
behavior and the probability amplitude is peaked in a determinate region. ii)
The GUP wave packets provide the right behavior in the establishment of a
quasi-isotropic configuration for the Universe.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 14:19:18 GMT"
},
{
"version": "v2",
"created": "Mon, 10 Dec 2007 09:41:46 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Battisti",
"Marco Valerio",
""
],
[
"Montani",
"Giovanni",
""
]
] |
0707.2727 | Antony Lewis | Antony Lewis | Linear effects of perturbed recombination | 5 pages; for more details of effect on 21cm see astro-ph/0702600;
code available at http://camb.info/sources/ | Phys.Rev.D76:063001,2007 | 10.1103/PhysRevD.76.063001 | null | astro-ph | null | Perturbations in the ionization fraction after recombination affect the
Compton cooling of density perturbations. Once the gas temperature starts to
decouple from the CMB temperature, ionization fraction perturbations can have a
significant influence on the subsequent gas temperature perturbation evolution.
This directly affects the 21cm spin temperature of the gas, and also modifies
the small-scale baryon perturbation evolution via the difference in baryon
pressure. The effect on the gas temperature perturbations can be significant on
all scales, and galactic-scale baryon perturbations are modified at the percent
level at redshifts z >~ 100 where numerical simulations are typically started.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 14:20:07 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Lewis",
"Antony",
""
]
] |
0707.2728 | Lazhar Dhaouadi | Lazhar Dhaouadi | Prolate Spheroidal Wave Functions In q-Fourier Analysis | null | null | null | null | math.GM | null | The prolate spheroidal wave functions, which are a special case of the
spheroidal wave functions, possess a very surprising and unique property [6].
They are an orthogonal basis of both $L^2(-1,1)$ and the Paley-Wiener space of
bandlimited functions. They also satisfy a discrete orthogonality relation. No
other system of classical orthogonal functions is known to possess this strange
property. We prove that there are new systems possessing this property in
$q$-Fourier analysis. As application we give a new sampling formula with $q^n$
as sampling points, where 0 < q < 1.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 14:41:11 GMT"
},
{
"version": "v2",
"created": "Wed, 9 Apr 2008 19:19:29 GMT"
}
] | 2008-04-09T00:00:00 | [
[
"Dhaouadi",
"Lazhar",
""
]
] |
0707.2729 | Lazhar Dhaouadi | Lazhar Dhaouadi | q-Sturm-Liouville theory and the corresponding eigenfunction expansions | null | null | null | null | math.CA | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The aim of this paper is to study the $q$-Schr\"{o}dinger operator $$ L=
q(x)-\Delta_q, $$ where $q(x)$ is a given function of $x$ defined over
$\mathbb{R}_{q}^{+}=\{q^n,\quad n\in\mathbb Z\}$ and $\Delta_q$ is the
$q$-Laplace operator $$ \Delta_{q}f(x)=\frac{1}{x^{2}}[
f(q^{-1}x)-\frac{1+q}{q}f(x)+\frac{1}{q}f(qx)]. $$
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 14:42:10 GMT"
},
{
"version": "v2",
"created": "Thu, 17 Jul 2008 06:59:20 GMT"
}
] | 2008-07-17T00:00:00 | [
[
"Dhaouadi",
"Lazhar",
""
]
] |
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