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| versions
list | update_date
timestamp[s] | authors_parsed
sequence |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
0704.2301 | Victor Flambaum | V. V. Flambaum and M. G. Kozlov | Enhanced sensitivity to time-variation of m_p/m_e in the inversion
spectrum of ammonia | null | Phys.Rev.Lett.98:240801,2007 | 10.1103/PhysRevLett.98.240801 | null | astro-ph hep-ph physics.atom-ph physics.space-ph | null | We calculate the sensitivity of the inversion spectrum of ammonia to possible
time-variation of the ratio of the proton mass to the electron mass,
mu=m_p/m_e. For the inversion transition (lambda= 1.25 cm^{-1}) the relative
frequency shift is significantly enhanced: delta(omega)/omega=-4.46,
delta(mu)/mu. This enhancement allows one to increase sensitivity to the
time-variation of mu using NH_3 spectra for high redshift objects. We use
published data on microwave spectra of the object B0218+357 to place the limit
delta(mu)/mu =(0.6 +/- 1.9) 10^{-6} at redshift z=0.6847; this limit is several
times better than the limits obtained by different methods and may be
significantly improved. Assuming linear time dependence we obtain
dot{mu}/mu=(-1 +/- 3) 10^{-16} yr^{-1}.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 09:30:06 GMT"
},
{
"version": "v2",
"created": "Thu, 19 Apr 2007 00:55:07 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Flambaum",
"V. V.",
""
],
[
"Kozlov",
"M. G.",
""
]
] |
0704.2302 | Mohammad Vahid Takook | M. Naseri, S. Rouhani and M.V. Takook | Casimir effect on nontrivial topology spaces in Krein space quantization | 6 pages | null | null | null | gr-qc | null | Casimir effect of a topologically nontrivial two-dimensional space-time,
through Krein space quantization [1,2], has been calculated. In other words,
auxiliary negative norm states have been utilized here. Presence of negative
norm states play the role of an automatic renormalization device for the
theory. The negative norm states (which do not interact with the physical
world) could be chosen in two perspective. In the first case our method results
in zero or vanishing values for energy. In the second case, however, the result
are the same as the renormalization procedure.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 09:33:42 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Naseri",
"M.",
""
],
[
"Rouhani",
"S.",
""
],
[
"Takook",
"M. V.",
""
]
] |
0704.2303 | Andrea Ferrari | P. H. Tan, A. G. Rozhin, T. Hasan, P. Hu, V. Scardaci, W. I. Milne, A.
C. Ferrari | Exciton energy transfer in nanotube bundles | 5 pages, 5 figures | Phys. Rev. Lett. 99, 137402 (2007) | 10.1103/PhysRevLett.99.137402 | null | cond-mat.mtrl-sci | null | Photoluminescence is commonly used to identify the electronic structure of
individual nanotubes. But, nanotubes naturally occur in bundles. Thus, we
investigate photoluminescence of nanotube bundles. We show that their complex
spectra are simply explained by exciton energy transfer between adjacent tubes,
whereby excitation of large gap tubes induces emission from smaller gap ones
via Forster interaction between excitons. The consequent relaxation rate is
faster than non-radiative recombination, leading to enhanced photoluminescence
of acceptor tubes. This fingerprints bundles with different compositions and
opens opportunities to optimize them for opto-electronics.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 09:35:36 GMT"
}
] | 2015-05-13T00:00:00 | [
[
"Tan",
"P. H.",
""
],
[
"Rozhin",
"A. G.",
""
],
[
"Hasan",
"T.",
""
],
[
"Hu",
"P.",
""
],
[
"Scardaci",
"V.",
""
],
[
"Milne",
"W. I.",
""
],
[
"Ferrari",
"A. C.",
""
]
] |
0704.2304 | Nelson Vieira | P. Cerejeiras and N. Vieira | Factorization of the Non-Stationary Schrodinger Operator | Accepted for publication in Advances in Applied Clifford Algebras | null | 10.1007/s00006-007-0039-6 | null | math-ph math.AP math.MP | null | We consider a factorization of the non-stationary Schrodinger operator based
on the parabolic Dirac operator introduced by Cerejeiras/ Kahler/ Sommen. Based
on the fundamental solution for the parabolic Dirac operators, we shall
construct appropriated Teodorescu and Cauchy-Bitsadze operators. Afterwards we
will describe how to solve the nonlinear Schrodinger equation using Banach
fixed point theorem.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 09:44:46 GMT"
},
{
"version": "v2",
"created": "Fri, 15 Jun 2007 12:38:57 GMT"
}
] | 2011-11-09T00:00:00 | [
[
"Cerejeiras",
"P.",
""
],
[
"Vieira",
"N.",
""
]
] |
0704.2305 | Fred Lahuis | Fred Lahuis, Ewine F. van Dishoeck, Geoffrey A. Blake, Neal J. Evans
II, Jacqueline E. Kessler-Silacci, and Klaus M. Pontoppidan | c2d Spitzer IRS Spectra of Disks around T Tauri Stars. III. [Ne II], [Fe
I], and H_2 gas-phase lines | Accepted for publication in ApJ. 19 pages, 11 figures, and 4 tables,
f7,f10a, f11a, and f11b replaced with slightly modified versions | Astrophys.J.665:492-511,2007 | 10.1086/518931 | null | astro-ph | null | We present a survey of mid-infrared gas-phase lines toward a sample of 76
circumstellar disks around low mass pre-main sequence stars from the Spitzer
"Cores to Disks" legacy program. We report the first detections of [Ne II] and
[Fe I] toward classical T Tauri stars in ~20% respectively ~9% of our sources.
The observed [Ne II] line fluxes and upper limits are consistent with [Ne II]
excitation in an X-ray irradiated disk around stars with X-ray luminosities
L_X=10^{29}-10^{31} erg s^{-1}. [Fe I] is detected at ~10^-5-10^-4 L_Sun, but
no [S I] or [Fe II] is detected down to ~10^{-6} L_Sun. The [Fe I] detections
indicate the presence of gas-rich disks with masses of >~0.1 M_J. No H_2 0-0
S(0) and S(1) disk emission is detected, except for S(1) toward one source.
These data give upper limits on the warm (T~100-200K) gas mass of a few Jovian
masses, consistent with recent T Tauri disk models which include gas heating by
stellar radiation. Compact disk emission of hot (T>~500K) gas is observed
through the H_2 0-0 S(2) and/or S(3) lines toward ~8% of our sources. The line
fluxes are, however, higher by more than an order of magnitude than those
predicted by recent disk models, even when X-ray and excess UV radiation are
included. Similarly the [Ne II]/H_2 0-0 S(2) ratios for these sources are lower
than predicted, consistent with the presence of an additional hot molecular gas
component not included in current disk models. Oblique shocks of stellar winds
interacting with the disk can explain many aspects of the hot gas emission, but
are inconsistent with the non-detection of [S I] and [Fe II] lines.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 09:49:43 GMT"
},
{
"version": "v2",
"created": "Fri, 20 Apr 2007 20:40:20 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"Lahuis",
"Fred",
""
],
[
"van Dishoeck",
"Ewine F.",
""
],
[
"Blake",
"Geoffrey A.",
""
],
[
"Evans",
"Neal J.",
"II"
],
[
"Kessler-Silacci",
"Jacqueline E.",
""
],
[
"Pontoppidan",
"Klaus M.",
""
]
] |
0704.2306 | Dario Taverna | D. Taverna, M. Kociak, O. St\'ephan, A. Fabre, E. Finot, B. D\'ecamps
and C. Colliex | Probing physical properties of confined fluids within individual
nanobubbles | 4 pages, 4 figures | null | 10.1103/PhysRevLett.100.035301 | null | cond-mat.mtrl-sci | null | Spatially resolved electron energy-loss spectroscopy (EELS) in a scanning
transmission electron microscope (STEM) has been used to investigate as fluidic
phase in nanoubbles embedded in a metallic Pd90Pt10 matrix. Using the 1s->2p
excitation of the He atoms, maps of the He distribution, in particular of its
density an pressure in bubbles of different diameter have been realized, thus
providing an indication of the involved bubble formation mechanism. However,
the short-range Pauli repulsion mechanism between electrons on neighboring
atoms seems insufficient to interpret minute variations of the local local
measurements performed at the interface between the metal and the He bubble.
Simulations relying on the continuum dielectric model have show that these
deviations could be interpreted as an interfzce polarization effect on the He
atomic transition, which should be accounted for when measuring the densities
within the smaller bubbles.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 09:53:21 GMT"
}
] | 2016-08-14T00:00:00 | [
[
"Taverna",
"D.",
""
],
[
"Kociak",
"M.",
""
],
[
"Stéphan",
"O.",
""
],
[
"Fabre",
"A.",
""
],
[
"Finot",
"E.",
""
],
[
"Décamps",
"B.",
""
],
[
"Colliex",
"C.",
""
]
] |
0704.2307 | Martin Flechl | Bjarte Mohn, Martin Flechl and Johan Alwall | ATLAS Discovery Potential for the Charged Higgs Boson in H+ to tau nu
Decays | This paper has been withdrawn | ATL-PHYS-PUB-2007-006 | null | null | hep-ph | null | This paper has been withdrawn by the authors in order to comply with the
ATLAS publication policy and is now only available via the CERN cdsweb
(http://cdsweb.cern.ch/record/984015)
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 10:00:52 GMT"
},
{
"version": "v2",
"created": "Thu, 6 Sep 2007 17:17:01 GMT"
},
{
"version": "v3",
"created": "Fri, 7 Sep 2007 03:57:38 GMT"
}
] | 2011-11-09T00:00:00 | [
[
"Mohn",
"Bjarte",
""
],
[
"Flechl",
"Martin",
""
],
[
"Alwall",
"Johan",
""
]
] |
0704.2308 | Arlene Cristina Aguilar | A. C. Aguilar and J. Papavassiliou | On dynamical gluon mass generation | Special Article - QNP2006: 4th International Conference on Quarks and
Nuclear Physics, Madrid, Spain, 5-10 June 2006 | Eur.Phys.J.A31:742-745,2007 | 10.1140/epja/i2006-10281-7 | null | hep-ph | null | The effective gluon propagator constructed with the pinch technique is
governed by a Schwinger-Dyson equation with special structure and gauge
properties, that can be deduced from the correspondence with the background
field method. Most importantly the non-perturbative gluon self-energy is
transverse order-by-order in the dressed loop expansion, and separately for
gluonic and ghost contributions, a property which allows for a meanigfull
truncation. A linearized version of the truncated Schwinger-Dyson equation is
derived, using a vertex that satisfies the required Ward identity and contains
massless poles. The resulting integral equation, subject to a properly
regularized constraint, is solved numerically, and the main features of the
solutions are briefly discussed.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 10:02:15 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Aguilar",
"A. C.",
""
],
[
"Papavassiliou",
"J.",
""
]
] |
0704.2309 | Mark J. Reid | M. J. Reid, K. M. Menten, L. J. Greenhill and C. J. Chandler | Imaging the Ionized Disk of the High-Mass Protostar Orion-I | 16 pages, 1 table, 3 figures | Astrophys.J.664:950-955,2007 | 10.1086/518929 | null | astro-ph | null | We have imaged the enigmatic radio source-I (Orion-I) in the Orion-KL nebula
with the VLA at 43 GHz with 34 mas angular resolution. The continuum emission
is highly elongated and is consistent with that expected from a nearly edge-on
disk. The high brightness and lack of strong molecular lines from Orion-I can
be used to argue against emission from dust. Collisional ionization and H-minus
free-free opacity, as in Mira variables, require a central star with >10^5
Lsun, which is greater than infrared observations allow. However, if
significant local heating associated with accretion occurs, lower total
luminosities are possible. Alternatively, photo-ionization from an early B-type
star and p+/e- bremsstrahlung can explain our observations, and Orion-I may be
an example of ionized accretion disk surrounding a forming massive star. Such
accretion disks may not be able to form planets efficiently.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 15:00:05 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"Reid",
"M. J.",
""
],
[
"Menten",
"K. M.",
""
],
[
"Greenhill",
"L. J.",
""
],
[
"Chandler",
"C. J.",
""
]
] |
0704.2310 | Henrik Olofsson | H. Olofsson, S. {\AA}berg, P. Leboeuf | Semiclassical Theory of Bardeen-Cooper-Schrieffer Pairing-Gap
Fluctuations | 4 pages, 2 figures | Phys. Rev. Lett. 100, 037005 (2008) | 10.1103/PhysRevLett.100.037005 | null | cond-mat.supr-con | null | Superfluidity and superconductivity are genuine many-body manifestations of
quantum coherence. For finite-size systems the associated pairing gap
fluctuates as a function of size or shape. We provide a parameter free
theoretical description of pairing fluctuations in mesoscopic systems
characterized by order/chaos dynamics. The theory accurately describes
experimental observations of nuclear superfluidity (regular system), predicts
universal fluctuations of superconductivity in small chaotic metallic grains,
and provides a global analysis in ultracold Fermi gases.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 10:10:01 GMT"
},
{
"version": "v2",
"created": "Mon, 15 Oct 2007 14:32:25 GMT"
},
{
"version": "v3",
"created": "Fri, 25 Jan 2008 09:19:18 GMT"
}
] | 2011-11-09T00:00:00 | [
[
"Olofsson",
"H.",
""
],
[
"Åberg",
"S.",
""
],
[
"Leboeuf",
"P.",
""
]
] |
0704.2311 | Cosmin Crucean | Cosmin Crucean | Coulomb scattering of the Dirac field on de Sitter expanding universe | 12 pages, no figures | Mod.Phys.Lett.A22:2573-2585,2007 | 10.1142/S0217732307025480 | null | hep-th | null | The lowest order contribution of the amplitude of the Dirac-Coulomb
scattering in de Sitter spacetime is calculated assuming that the initial and
final states of the Dirac field are described by exact solutions of the free
Dirac equation on de Sitter spacetime with a given momentum and helicity. One
studies the difficulties that arises when one passes from the amplitude to
cross section.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 10:18:32 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Crucean",
"Cosmin",
""
]
] |
0704.2312 | Shung-ichi Ando | Shung-ichi Ando, Jae Won Shin, Chang Ho Hyun, Seung Woo Hong
(Sungkyunkwan U.) | Low energy proton-proton scattering in effective field theory | 23 pages, 6 eps figures, revised considerably, accepted for
publication in Phys. Rev. C | Phys.Rev.C76:064001,2007 | 10.1103/PhysRevC.76.064001 | null | nucl-th hep-ph | null | Low energy proton-proton scattering is studied in pionless effective field
theory. Employing the dimensional regularization and MS-bar and power
divergence subtraction schemes for loop calculation, we calculate the
scattering amplitude in 1S0 channel up to next-to-next-to leading order and fix
low-energy constants that appear in the amplitude by effective range
parameters. We study regularization scheme and scale dependence in separation
of Coulomb interaction from the scattering length and effective range for the
S-wave proton-proton scattering.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 10:47:29 GMT"
},
{
"version": "v2",
"created": "Mon, 7 May 2007 09:50:23 GMT"
},
{
"version": "v3",
"created": "Fri, 2 Nov 2007 12:17:22 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Ando",
"Shung-ichi",
"",
"Sungkyunkwan U."
],
[
"Shin",
"Jae Won",
"",
"Sungkyunkwan U."
],
[
"Hyun",
"Chang Ho",
"",
"Sungkyunkwan U."
],
[
"Hong",
"Seung Woo",
"",
"Sungkyunkwan U."
]
] |
0704.2313 | Farhad Jafarpour Hamadani | F H Jafarpour and B Ghavami | Discontinuous Phase Transition in an Exactly Solvable One-Dimensional
Creation-Annihilation System | Revised, 8 pages, 1 EPS figure. Accepted for publication in Journal
of Statistical Mechanics: theory and experiment | null | 10.1088/1742-5468/2007/08/P08010 | null | cond-mat.stat-mech | null | An exactly solvable reaction-diffusion model consisting of first-class
particles in the presence of a single second-class particle is introduced on a
one-dimensional lattice with periodic boundary condition. The number of
first-class particles can be changed due to creation and annihilation
reactions. It is shown that the system undergoes a discontinuous phase
transition in contrast to the case where the density of the second-class
particles is finite and the phase transition is continuous.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 10:44:47 GMT"
},
{
"version": "v2",
"created": "Fri, 22 Jun 2007 15:18:43 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Jafarpour",
"F H",
""
],
[
"Ghavami",
"B",
""
]
] |
0704.2314 | Daniel Gamermann | D.Gamermann, E.Oset | Axial Resonances in the Open and Hidden Charm Sectors | Final published version | Eur.Phys.J.A33:119-131,2007 | 10.1140/epja/i2007-10435-1 | null | hep-ph | null | A SU(4) flavor symmetrical Lagrangian is constructed for the interaction of
the pseudo-scalar mesons with the vector mesons. SU(4) symmetry is broken to
SU(3) by suppression of terms in the Lagrangian where the interaction should be
driven by charmed mesons. Chiral symmetry can be restored by setting this new
SU(4) symmetry breaking parameters to zero. Unitarization in coupled channels
leads to the dynamical generation of resonances. Many known axial resonances
can be identified including the new controversial X(3872) and the structure
found recently by Belle around 3875 MeV in the hidden charm sector. Also new
resonances are predicted, some of them with exotic quantum numbers.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 12:11:28 GMT"
},
{
"version": "v2",
"created": "Fri, 28 Mar 2008 14:02:36 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Gamermann",
"D.",
""
],
[
"Oset",
"E.",
""
]
] |
0704.2315 | Miguel Angel Martin-Delgado | A. Bermudez, M.A. Martin-Delgado, E. Solano | Exact Mapping of the 2+1 Dirac Oscillator onto the Jaynes-Cummings
Model: Ion-Trap Experimental Proposal | Revtex4, submitted for publication | Rap. Comm. PRA 76, 041801 (R) (2007) | 10.1103/PhysRevA.76.041801 | null | quant-ph | null | We study the dynamics of the 2+1 Dirac oscillator exactly and find spin
oscillations due to a {\it Zitterbewegung} of purely relativistic origin. We
find an exact mapping of this quantum-relativistic system onto a
Jaynes-Cummings model, describing the interaction of a two-level atom with a
quantized single-mode field. This equivalence allows us to map a series of
quantum optical phenomena onto the relativistic oscillator, and viceversa. We
make a realistic experimental proposal, at reach with current technology, for
studying the equivalence of both models using a single trapped ion.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 10:53:59 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Bermudez",
"A.",
""
],
[
"Martin-Delgado",
"M. A.",
""
],
[
"Solano",
"E.",
""
]
] |
0704.2316 | Ladislav \v{S}amaj | B. Jancovici, L. Samaj | Correlations and sum rules in a half-space for a quantum two-dimensional
one-component plasma | 15 pages, to appear in J. Stat. Mech. (JSTAT) | J. Stat. Mech. (2007) P05009 | 10.1088/1742-5468/2007/05/P05009 | LPT Orsay 07-21 | cond-mat.stat-mech quant-ph | null | This paper is the continuation of a previous one [L. {\v{S}}amaj and B.
Jancovici, 2007 {\it J. Stat. Mech.} P02002]; for a nearly classical quantum
fluid in a half-space bounded by a plain plane hard wall (no image forces), we
had generalized the Wigner-Kirkwood expansion of the equilibrium statistical
quantities in powers of Planck's constant $\hbar$. As a model system for a more
detailed study, we consider the quantum two-dimensional one-component plasma: a
system of charged particles of one species, interacting through the logarithmic
Coulomb potential in two dimensions, in a uniformly charged background of
opposite sign, such that the total charge vanishes. The corresponding classical
system is exactly solvable in a variety of geometries, including the present
one of a half-plane, when $\beta e^2=2$, where $\beta$ is the inverse
temperature and $e$ is the charge of a particle: all the classical $n$-body
densities are known. For the quantum one-component plasma, two sum rules
involving the truncated two-body density (and, for one of them, the density
profile) have been derived, a long time ago, by heuristic macroscopic
arguments: one sum rule is about the asymptotic form along the wall of the
truncated two-body density, the other one is about the dipole moment of the
structure factor. In the two-dimensional case at $\beta e^2=2$, we have now
explicit expressions up to order $\hbar^2$ of these two quantum densities, thus
we can microscopically check the sum rules at this order. The checks are
positive, reinforcing the idea that the sum rules are correct.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 10:56:30 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Jancovici",
"B.",
""
],
[
"Samaj",
"L.",
""
]
] |
0704.2317 | Iliya Karlin | E. Chiavazzo, I.V. Karlin | Quasi Equilibrium Grid Algorithm: geometric construction for model
reduction | 31 pages, 13 figures | J. Comput. Phys. 227, 5535-5560 (2008) | 10.1016/j.jcp.2008.02.006 | null | cond-mat.stat-mech | null | The Method of Invariant Grid (MIG) is an iterative procedure for model
reduction in chemical kinetics which is based on the notion of Slow Invariant
Manifold (SIM) [1-4]. Important role, in that method, is played by the initial
grid which, once refined, gives a description of the invariant manifold: the
invariant grid. A convenient way to get a first approximation of the SIM is
given by the Spectral Quasi Equilibrium Manifold (SQEM) [1-2]. In the present
paper, a flexible numerical method to construct the discrete analog of a Quasi
Equilibrium Manifold, in any dimension, is presented. That object is named
Quasi Equilibrium Grid (QEG), while the procedure Quasi Equilibrium Grid
Algorithm. Extensions of the QEM notion are also suggested. The QEG is a
numerical tool which can be used to find a grid-based approximation for the
locus of minima of a convex function under some linear constraints. The method
is validated by construction of one and two-dimensional grids for model
hydrogen oxidation reaction.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 15:34:48 GMT"
}
] | 2008-06-03T00:00:00 | [
[
"Chiavazzo",
"E.",
""
],
[
"Karlin",
"I. V.",
""
]
] |
0704.2318 | Gabriel T\"or\"ok Jr. | Zdenek Stuchlik, Gabriel Torok, Pavel Bakala | On a multi-resonant origin of high frequency quasiperiodic oscillations
in the neutron-star X-ray binary 4U 1636-53 | 7 pages, 3 figures, submitted to A&A | null | null | null | astro-ph | null | The results we presented were biased because of the typing error in the code
transcription of the equation (A.12). We will replace by the corrected version
soon. The brief of the corrected results can be found at
http://www.physics.cz/research/doc/posters/1181038112_0.pdf
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 17:40:01 GMT"
},
{
"version": "v2",
"created": "Tue, 5 Jun 2007 21:03:58 GMT"
}
] | 2007-06-13T00:00:00 | [
[
"Stuchlik",
"Zdenek",
""
],
[
"Torok",
"Gabriel",
""
],
[
"Bakala",
"Pavel",
""
]
] |
0704.2319 | Benito Al\'en | G. Munoz-Matutano, B. Alen, J. Martinez-Pastor, L. Seravalli, P.
Frigeri and S. Franchi | Optical pumping of charged excitons in unintentionally doped InAs
quantum dots | 4 pages and 3 figures submitted to APL | Nanotechnology 19 (2008) 145711 | 10.1088/0957-4484/19/14/145711 | null | cond-mat.mes-hall | null | As an alternative to commonly used electrical methods, we have investigated
the optical pumping of charged exciton complexes addressing impurity related
transitions with photons of the appropriate energy. Under these conditions, we
demonstrate that the pumping fidelity can be very high while still maintaining
a switching behavior between the different excitonic species. This mechanism
has been investigated for single quantum dots of different size present in the
same sample and compared with the direct injection of spectator electrons from
nearby donors.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 13:19:26 GMT"
}
] | 2010-07-15T00:00:00 | [
[
"Munoz-Matutano",
"G.",
""
],
[
"Alen",
"B.",
""
],
[
"Martinez-Pastor",
"J.",
""
],
[
"Seravalli",
"L.",
""
],
[
"Frigeri",
"P.",
""
],
[
"Franchi",
"S.",
""
]
] |
0704.2320 | Jacek Szklarski | J. Szklarski | Reduction of boundary effects in spiral MRI experiment PROMISE | 8 pages, 9 figures. Accepted to AN | Astron.Nachr. 328 (2007) 499 | 10.1002/asna.200710774 | null | astro-ph | null | Magnetorotational instability (MRI) is one of the most important and most
common instabilities in astrophysics, it is widely accepted that it serves as a
source of turbulent viscosity in accretion disks -- the most energy efficient
objects in the Universe. However it is very difficult to bring this process
down on earth and model it in a laboratory experiment. Several different
approaches have been proposed, one of the most recent is PROMISE
(Potsdam-ROssendorf Magnetorotational InStability Experiment). It consists of a
flow of a liquid metal between two rotating cylinders under applied
current-free spiral magnetic field. The cylinders must be covered with plates
which introduce additional end-effects which alter the flow and make it more
difficult to clearly distinguish between MRI stable and unstable state. In this
paper we propose simple and inexpensive improvement to the PROMISE experiment
which would reduce those undesirable effects.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 12:03:44 GMT"
},
{
"version": "v2",
"created": "Mon, 21 May 2007 14:37:41 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Szklarski",
"J.",
""
]
] |
0704.2321 | Solange Odile Saliu | C. Bizdadea, E. M. Cioroianu, A. C. Lungu, S. O. Saliu | No multi-graviton theories in the presence of a Dirac field | 48 pages | JHEP0502:016,2005 | 10.1088/1126-6708/2005/02/016 | null | hep-th | null | The cross-couplings among several massless spin-two fields (described in the
free limit by a sum of Pauli-Fierz actions) in the presence of a Dirac field
are investigated in the framework of the deformation theory based on local BRST
cohomology. Under the hypotheses of locality, smoothness of the interactions in
the coupling constant, Poincare invariance, (background) Lorentz invariance and
the preservation of the number of derivatives on each field, we prove that
there are no consistent cross-interactions among different gravitons in the
presence of a Dirac field. The basic features of the couplings between a single
Pauli-Fierz field and a Dirac field are also emphasized.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 11:26:00 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Bizdadea",
"C.",
""
],
[
"Cioroianu",
"E. M.",
""
],
[
"Lungu",
"A. C.",
""
],
[
"Saliu",
"S. O.",
""
]
] |
0704.2322 | Yuri Genenko | F. Neumann, Y. A. Genenko, C. Melzer and H. von Seggern | Self consistent theory of unipolar charge-carrier injection in
metal/insulator/metal systems | 21 pages, 8 figures | J. Appl. Phys. 100, 084511 (2006) | 10.1063/1.2360383 | null | cond-mat.mtrl-sci | null | A consistent device model to describe current-voltage characteristics of
metal/insulator/metal systems is developed. In this model the insulator and the
metal electrodes are described within the same theoretical framework by using
density of states distributions. This approach leads to differential equations
for the electric field which have to be solved in a self consistent manner by
considering the continuity of the electric displacement and the electrochemical
potential in the complete system. The model is capable of describing the
current-voltage characteristics of the metal/insulator/metal system in forward
and reverse bias for arbitrary values of the metal/ insulator injection
barriers. In the case of high injection barriers, approximations are provided
offering a tool for comparison with experiments. Numerical calculations are
performed exemplary using a simplified model of an organic semiconductor.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 11:26:58 GMT"
}
] | 2015-05-13T00:00:00 | [
[
"Neumann",
"F.",
""
],
[
"Genenko",
"Y. A.",
""
],
[
"Melzer",
"C.",
""
],
[
"von Seggern",
"H.",
""
]
] |
0704.2323 | Yung-mau Nie | Yung-mau Nie | Bandstructure and optical properties of $\alpha-LiIO_{3}$ crystal | 13 pages, 7 figures | null | null | null | physics.optics | null | The bandstructure was calculated by the full-potential linearized augmented
plane wave method. The result reveals two important insights to the novel
second harmonic generation (SHG) of alpha-phase lithium iodate
($\alpha-LiIO_{3}$) crystal: the existence of finite intra-band momentum matrix
elements due to the non-inversion symmetry of the crystal illuminating the
potential of the intra-band transition, and the strong covalent bonding between
the $I$-atoms and the ligand $O$-atoms resulting the condition of the
double-resonance. An inter-band transition scenario in SHG as $\alpha-LiIO_{3}$
in nano-structure is proposed. The optical properties were calculated within
the theoretical framework of the time-dependent perturbation of the
independent-particle model. The dielectric tensors and the refractive index
were evaluated. Comparisons between the predictions and the results were made:
the x-ray near edge absorption spectra; the refractive index at the static
limit, and at finite frequencies. Possible factors attributing the calculation
errors is discussed.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 11:29:36 GMT"
},
{
"version": "v2",
"created": "Thu, 19 Apr 2007 03:09:46 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Nie",
"Yung-mau",
""
]
] |
0704.2324 | Viktoriya Semeshenko Mrs | Viktoriya Semeshenko, Mirta B. Gordon and Jean-Pierre Nadal | Collective states in social systems with interacting learning agents | 18 pages, 26 figures | null | 10.1016/j.physa.2008.04.019 | null | physics.soc-ph | null | We consider a social system of interacting heterogeneous agents with learning
abilities, a model close to Random Field Ising Models, where the random field
corresponds to the idiosyncratic willingness to pay. Given a fixed price,
agents decide repeatedly whether to buy or not a unit of a good, so as to
maximize their expected utilities. We show that the equilibrium reached by the
system depends on the nature of the information agents use to estimate their
expected utilities.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 11:32:49 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Semeshenko",
"Viktoriya",
""
],
[
"Gordon",
"Mirta B.",
""
],
[
"Nadal",
"Jean-Pierre",
""
]
] |
0704.2325 | Oleg Matveev | O. A. Matveev, A. I. Terent'ev | Basic principles of postgrowth annealing of CdTe:Cl ingot to obtain
semi-insulating crystals | 6 pages, 6 figures | Semiconductor. Vol. 34. No. 11, 2000. pp. 1264-1269 | 10.1134/1.1325420 | null | cond-mat.mtrl-sci | null | The process of annealing of a CdTe:Cl ingot during its cooling after growth
was studied. The annealing was performed in two stages: a high-temperature
stage, with an approximate equality of chlorine and cadmium vacancy
concentrations established at the thermodynamic equilibrium between the crystal
and vapors of volatile components, and a low-temperature stage, with charged
defects interacting to form neutral associations. The chlorine concentrations
necessary to obtain semi-insulating crystals were determined for various ingot
cooling rates in the high temperature stage. The dependence of the chlorine
concentration [Cl+Te] in the ingot on the temperature of annealing in the
high-temperature stage was found. The carrier lifetimes and drift mobilities
were obtained in relation to the temperature and cadmium vapor pressure in the
postgrowth annealing of the ingot.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 11:38:09 GMT"
}
] | 2015-05-13T00:00:00 | [
[
"Matveev",
"O. A.",
""
],
[
"Terent'ev",
"A. I.",
""
]
] |
0704.2326 | Vincent Caudrelier | V. Caudrelier | On a systematic approach to defects in classical integrable field
theories | 27 pages, no figures. Final version accepted for publication.
References added and section 5 amended | IJGMMP vol.5, No. 7 (2008), 1085-1108 | 10.1142/S0219887808003223 | null | math-ph hep-th math.MP nlin.SI | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We present an inverse scattering approach to defects in classical integrable
field theories. Integrability is proved systematically by constructing the
generating function of the infinite set of modified integrals of motion. The
contribution of the defect to all orders is explicitely identified in terms of
a defect matrix. The underlying geometric picture is that those defects
correspond to Backlund transformations localized at a given point. A
classification of defect matrices as well as the corresponding defect
conditions is performed. The method is applied to a collection of well-known
integrable models and previous results are recovered (and extended) directly as
special cases. Finally, a brief discussion of the classical $r$-matrix approach
in this context shows the relation to inhomogeneous lattice models and the need
to resort to lattice regularizations of integrable field theories with defects.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 11:41:48 GMT"
},
{
"version": "v2",
"created": "Wed, 14 Jan 2009 10:56:55 GMT"
}
] | 2015-05-13T00:00:00 | [
[
"Caudrelier",
"V.",
""
]
] |
0704.2327 | Yusuke Sasano | Yusuke Sasano | Symmetries in the system of type $A_5^{(2)}$ | 4 pages, 1 figure | null | null | null | math.AG | null | In this paper, we propose a 3-parameter family of coupled Painlev\'e III
systems in dimension four with affine Weyl group symmetry of type $A_5^{(2)}$.
We also propose its symmetric form in which the $A_5^{(2)}$-symmetries become
clearly visible.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 11:49:25 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Sasano",
"Yusuke",
""
]
] |
0704.2328 | Fabio Zanolin | Marina Pireddu, Fabio Zanolin | Cutting surfaces and applications to periodic points and chaotic-like
dynamics | 37 pages, 4 figures | null | null | null | math.DS | null | In this paper we propose an elementary topological approach which unifies and
extends various different results concerning fixed points and periodic points
for maps defined on sets homeomorphic to rectangles embedded in euclidean
spaces. We also investigate the associated discrete semidynamical systems in
view of detecting the presence of chaotic-like dynamics.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 11:57:35 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Pireddu",
"Marina",
""
],
[
"Zanolin",
"Fabio",
""
]
] |
0704.2329 | Carlos M. Naon | L. Arrachea, Carlos Na\'on, Mariano Salvay | Quantum pump effect in one-dimensional systems of Dirac fermions | 8 pages, 5 figures | Phys. Rev. B 76, 165401, (2007) | 10.1103/PhysRevB.76.165401 | null | cond-mat.mes-hall | null | We investigate the behavior of the directed current in one-dimensional
systems of Dirac fermions driven by local periodic potentials in the forward as
well in backscattering channels. We treat the problem with Keldysh
non-equilibrium Green's function formalism. We present the exact solution for
the case of an infinite wire and show that in this case the dc current vanishes
identically. We also investigate a confined system consistent in an annular
arrangement coupled to a particle reservoir. We present a perturbative
treatment that allows for the analytical expressions of the dc current in the
lowest order of the amplitudes of the potential. We also present results
obtained from the exact numerical solution of the problem.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 11:59:04 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Arrachea",
"L.",
""
],
[
"Naón",
"Carlos",
""
],
[
"Salvay",
"Mariano",
""
]
] |
0704.2330 | Oleg Matveev | O. A. Matveev, A. I. Terent'ev, V. P. Karpenko, N. K. Zelenina, A.
Fauler, M. Federle, and K. W. Benz | CdZnTe:Cl crystals for X-ray computer tomography detectors | 3 pages, 2 figures | phys. stat. sol. (b) 229, No. 2, 1073-1076 (2002) | null | null | cond-mat.mtrl-sci | null | Processes of growth of semi-insulating Cd(1-x)Zn(x)Te:Cl crystals (x = 0.0002
and 0.1) of n-type conductivity are investigated. From the grown crystals
detectors for X-ray computer tomography with small value of photocurrent memory
(afterglow) (0.1-0.3%) are obtained.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 12:00:54 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Matveev",
"O. A.",
""
],
[
"Terent'ev",
"A. I.",
""
],
[
"Karpenko",
"V. P.",
""
],
[
"Zelenina",
"N. K.",
""
],
[
"Fauler",
"A.",
""
],
[
"Federle",
"M.",
""
],
[
"Benz",
"K. W.",
""
]
] |
0704.2331 | Yusuke Sasano | Yusuke Sasano | Symmetries in the system of type $D_4^{(1)}$ | 4 pages, 1 figure | null | null | null | math.AG | null | In this paper, we propose a 4-parameter family of coupled Painlev\'e III
systems in dimension four with affine Weyl group symmetry of type $D_4^{(1)}$.
We also propose its symmetric form in which the $D_4^{(1)}$-symmetries become
clearly visible.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 12:01:31 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Sasano",
"Yusuke",
""
]
] |
0704.2332 | Frithjof Brauer | F. Brauer, C. P. Dullemond, A. Johansen, Th. Henning, H. Klahr, A.
Natta | Survival of the mm-cm size grain population observed in protoplanetary
disks | Accepted for publication in Astronomy and Astrophysics | null | 10.1051/0004-6361:20066865 | null | astro-ph | null | Millimeter interferometry provides evidence for the presence of mm to cm size
"pebbles" in the outer parts of disks around pre-main-sequence stars. The
observations suggest that large grains are produced relatively early in disk
evolution (< 1 Myr) and remain at large radii for longer periods of time (5 to
10 Myr). Simple theoretical estimates of the radial drift time of solid
particles, however, imply that they would drift inward over a time scale of
less than 0.1 Myr. In this paper, we address this conflict between theory and
observation, using more detailed theoretical models, including the effects of
sedimentation, collective drag forces and turbulent viscosity. We find that,
although these effects slow down the radial drift of the dust particles, this
reduction is not sufficient to explain the observationally determined long
survival time of mm/cm-sized grains in protoplanetary disks. However, if for
some reason the gas to dust ratio in the disk is reduced by at least a factor
of 20 from the canonical value of 100 (for instance through photoevaporation of
the gas), then the radial drift time scales become sufficiently large to be in
agreement with observations.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 13:57:27 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Brauer",
"F.",
""
],
[
"Dullemond",
"C. P.",
""
],
[
"Johansen",
"A.",
""
],
[
"Henning",
"Th.",
""
],
[
"Klahr",
"H.",
""
],
[
"Natta",
"A.",
""
]
] |
0704.2333 | Mirta B. Gordon | Mirta B. Gordon and Jean-Pierre Nadal and Denis Phan and Viktoriya
Semeshenko | Discrete Choices under Social Influence: Generic Properties | 42 pages, 15 figures | null | null | null | physics.soc-ph | null | We consider a model of socially interacting individuals that make a binary
choice in a context of positive additive endogenous externalities. It
encompasses as particular cases several models from the sociology and economics
literature. We extend previous results to the case of a general distribution of
idiosyncratic preferences, called here Idiosyncratic Willingnesses to Pay
(IWP). Positive additive externalities yield a family of inverse demand curves
that include the classical downward sloping ones but also new ones with non
constant convexity. When j, the ratio of the social influence strength to the
standard deviation of the IWP distribution, is small enough, the inverse demand
is a classical monotonic (decreasing) function of the adoption rate. Even if
the IWP distribution is mono-modal, there is a critical value of j above which
the inverse demand is non monotonic, decreasing for small and high adoption
rates, but increasing within some intermediate range. Depending on the price
there are thus either one or two equilibria. Beyond this first result, we
exhibit the generic properties of the boundaries limiting the regions where the
system presents different types of equilibria (unique or multiple). These
properties are shown to depend only on qualitative features of the IWP
distribution: modality (number of maxima), smoothness and type of support
(compact or infinite). The main results are summarized as phase diagrams in the
space of the model parameters, on which the regions of multiple equilibria are
precisely delimited.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 12:03:44 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Gordon",
"Mirta B.",
""
],
[
"Nadal",
"Jean-Pierre",
""
],
[
"Phan",
"Denis",
""
],
[
"Semeshenko",
"Viktoriya",
""
]
] |
0704.2334 | Solange Odile Saliu | C. Bizdadea, E. M. Cioroianu, D. Cornea, S. O. Saliu, S. C. Sararu | No interactions for a collection of spin-two fields intermediated by a
massive Rarita-Schwinger field | 61 pages | Eur.Phys.J.C48:265-289,2006 | 10.1140/epjc/s2006-02620-9 | null | hep-th | null | The cross-couplings among several massless spin-two fields (described in the
free limit by a sum of Pauli-Fierz actions) in the presence of a massive
Rarita-Schwinger field are investigated in the framework of the deformation
theory based on local BRST cohomology. Under the hypotheses of locality,
smoothness of the interactions in the coupling constant, Poincare invariance,
Lorentz covariance, and the preservation of the number of derivatives on each
field, we prove that there are no consistent cross-interactions among different
gravitons with a positively defined metric in internal space in the presence of
a massive Rarita-Schwinger field. The basic features of the couplings between a
single Pauli-Fierz field and a massive Rarita-Schwinger field are also
emphasized.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 12:05:05 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Bizdadea",
"C.",
""
],
[
"Cioroianu",
"E. M.",
""
],
[
"Cornea",
"D.",
""
],
[
"Saliu",
"S. O.",
""
],
[
"Sararu",
"S. C.",
""
]
] |
0704.2335 | Elisabetta Caffau | Elisabetta Caffau (GEPI), Rosanna Faraggiana (DAUT), Piercarlo
Bonifacio (GEPI, CIFIST, OAT), Hans-G. Ludwig (GEPI, CIFIST), Matthias
Steffen (AIP) | Sulphur abundances from the SI near-infrared triplet at 1045 nm | null | null | 10.1051/0004-6361:20077182 | null | astro-ph | null | context : Unlike silicon and calcium, sulphur is an alpha-element which does
not form dust. Some of the available observations of the evolution of sulphur
with metallicity indicate an increased scatter of sulphur to iron ratios at low
metallicities or even a bimodal distribution, with some stars showing constant
S/Fe at all metallicities and others showing an increasing S/Fe ratio with
decreasing metallicity. In metal-poor stars SI lines of Multiplet 1 at 920 nm
are not yet too weak to permit to measure the sulphur abundance A(S), however
in ground-based observations they are severely affected by telluric lines. aims
: We investigate the possibility to measure sulphur abundances from SI Mult. 3
at 1045 nm lines, which lie in the near infra-red. These are slightly weaker
than those of Mult. 1, but lie in a range not affected by telluric lines.
method We investigate the lines of Mult.3 in the Sun (G2V), Procyon (F5V), HD
33256 (F5V), HD 25069 (G9V) and epsilon Eri (HD 22049, K2V). For the Sun and
Procyon the analysis has been performed with CO5BOLD 3D hydrodynamical model
atmospheres, for the other three stars, for which hydrodynamical simulations
are not available, the analysis has been performed using 1D model atmospheres.
results For our sample of stars we find a global agreement of A(S) from lines
of different multiplets. conclusions : Our results suggest that the infrared
lines of Mult. 3 are a viable indicator of the sulphur abundance which, because
of the intrinsic strength of this multiplet, should be suitable to study the
trend of [S/Fe] at low metallicities.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 12:11:09 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Caffau",
"Elisabetta",
"",
"GEPI"
],
[
"Faraggiana",
"Rosanna",
"",
"DAUT"
],
[
"Bonifacio",
"Piercarlo",
"",
"GEPI, CIFIST, OAT"
],
[
"Ludwig",
"Hans-G.",
"",
"GEPI, CIFIST"
],
[
"Steffen",
"Matthias",
"",
"AIP"
]
] |
0704.2336 | Seiko Kawamura | S. Ohira-Kawamura, H. Shishido, A. Yoshida, R. Okazaki, H.
Kawano-Furukawa, T. Shibauchi, H. Harima and Y. Matsuda | Competition between unconventional superconductivity and incommensurate
antiferromagnetic order in CeRh1-xCoxIn5 | RevTeX4, 4 pages, 4 eps figures; corrected a typo and a reference | null | 10.1103/PhysRevB.76.132507 | null | cond-mat.str-el cond-mat.supr-con | null | Elastic neutron diffraction measurements were performed on the quasi-two
dimensional heavy fermion system CeRh1-xCoxIn5, ranging from an incommensurate
antiferromagnet for low x to an unconventional superconductor on the Co-rich
end of the phase diagram. We found that the superconductivity competes with the
incommensurate antiferromagnetic (AFM) order characterized by qI=(1/2, 1/2,
delta) with delta=0.298, while it coexists with the commensurate AFM order with
qc=(1/2, 1/2, 1/2). This is in sharp contrast to the CeRh1-xIrxIn5 system,
where both the commensurate and incommensurate magnetic orders coexist with the
superconductivity. These results reveal that particular areas on the Fermi
surface nested by qI play an active role in forming the superconducting state
in CeCoIn5.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 12:39:19 GMT"
},
{
"version": "v2",
"created": "Mon, 23 Apr 2007 02:52:45 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Ohira-Kawamura",
"S.",
""
],
[
"Shishido",
"H.",
""
],
[
"Yoshida",
"A.",
""
],
[
"Okazaki",
"R.",
""
],
[
"Kawano-Furukawa",
"H.",
""
],
[
"Shibauchi",
"T.",
""
],
[
"Harima",
"H.",
""
],
[
"Matsuda",
"Y.",
""
]
] |
0704.2337 | Clement Rau | Clement Rau (LATP) | Existence of graphs with sub exponential transitions probability decay
and applications | 46 pages | null | null | null | math.PR | null | In this paper, we present a complete proof of the construction of graphs with
bounded valency such that the simple random walk has a return probability at
time $n$ at the origin of order $exp(-n^{\alpha}),$ for fixed $\alpha \in
[0,1[$ and with Folner function $exp(n^{\frac{2\alpha}{1-\alpha}})$. We begin
by giving a more detailled proof of this result contained in (see
\cite{ershdur}). In the second part, we give an application of the existence of
such graphs. We obtain bounds of the correct order for some functional of the
local time of a simple random walk on an infinite cluster on the percolation
model.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 12:40:56 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Rau",
"Clement",
"",
"LATP"
]
] |
0704.2338 | Andreas von Kienlin | G. G. Lichti, E. Bottacini, P. Charlot, W. Collmar, D. Horan, A. von
Kienlin, A. Laehteenmaeki, K. Nilsson, D. Petry, A. Sillanpaeae, M.
Tornikoski, T. Weekes | INTEGRAL and Multiwavelength Observations of the Blazar Mrk 421 during
an Active Phase | 2 pages, 3 figures; to appear in the Proc. of the First Int. GLAST
Symp. (Stanford, Feb. 5-8, 2007), eds. S.Ritz, P.F.Michelson, and C.Meegan,
AIP Conf. Proc | AIP Conf.Proc.921:371-372,2007 | 10.1063/1.2757357 | null | astro-ph | null | A ToO observation of the TeV-emitting blazar Mrk 421 with INTEGRAL was
triggered in June 2006 by an increase of the RXTE count rate to more than 30
mCrab. The source was then observed with all INTEGRAL instruments with the
exception of the spectrometer SPI for a total exposure of 829 ks. During this
time several outbursts were observed by IBIS and JEM-X. Multiwavelength
observations were immediately triggered and the source was observed at radio,
optical and X-ray wavelengths up to TeV energies. The data obtained during
these observations are analysed with respect to spectral evolution and
correlated variability. Preliminary results of the analysis are presented in
this poster.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 12:48:30 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"Lichti",
"G. G.",
""
],
[
"Bottacini",
"E.",
""
],
[
"Charlot",
"P.",
""
],
[
"Collmar",
"W.",
""
],
[
"Horan",
"D.",
""
],
[
"von Kienlin",
"A.",
""
],
[
"Laehteenmaeki",
"A.",
""
],
[
"Nilsson",
"K.",
""
],
[
"Petry",
"D.",
""
],
[
"Sillanpaeae",
"A.",
""
],
[
"Tornikoski",
"M.",
""
],
[
"Weekes",
"T.",
""
]
] |
0704.2339 | Agung Budiyono | Agung Budiyono | Scale invariant quantum potential leading to globally self-trapped wave
function in Madelung fluid | 11 pages; changed content | null | null | null | physics.gen-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We show in spatially one dimensional Madelung fluid that a simple requirement
on local stability of the maximum of quantum probability density will, if
combined with the global scale invariance of quantum potential, lead to a class
of quantum probability densities globally being self-trapped by their own
self-generated quantum potentials, possessing only a finite-size spatial
support. It turns out to belong to a class of the most probable wave function
given its energy through the maximum entropy principle. We proceed to show that
there is a limiting case in which the quantum probability density becomes the
stationary-moving soliton-like solution of the Schr\"odinger equation.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 12:54:39 GMT"
},
{
"version": "v2",
"created": "Wed, 25 Apr 2007 15:58:58 GMT"
},
{
"version": "v3",
"created": "Fri, 4 May 2007 14:25:09 GMT"
},
{
"version": "v4",
"created": "Wed, 19 Aug 2009 05:46:24 GMT"
}
] | 2009-08-19T00:00:00 | [
[
"Budiyono",
"Agung",
""
]
] |
0704.2340 | Lie-Wen Chen | Lie-Wen Chen, Che Ming Ko, Bao-An Li, Gao-Chan Yong | Probing the Nuclear Symmetry Energy with Heavy-Ion Reactions Induced by
Neutron-Rich Nuclei | 29 pages, 35 figures. Invited review article for Frontiers of Physics
in China | Front.Phys.China2:327-357,2007 | 10.1007/s11467-007-0037-0 | null | nucl-th astro-ph nucl-ex | null | Heavy-ion reactions induced by neutron-rich nuclei provide a unique means to
investigate the equation of state of isospin-asymmetric nuclear matter,
especially the density dependence of the nuclear symmetry energy. In
particular, recent analyses of the isospin diffusion data in heavy-ion
reactions have already put a stringent constraint on the nuclear symmetry
energy around the nuclear matter saturation density. We review this exciting
result and discuss its implications on nuclear effective interactions and the
neutron skin thickness of heavy nuclei. In addition, we also review the
theoretical progress on probing the high density behaviors of the nuclear
symmetry energy in heavy-ion reactions induced by high energy radioactive
beams.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 04:13:32 GMT"
}
] | 2009-09-29T00:00:00 | [
[
"Chen",
"Lie-Wen",
""
],
[
"Ko",
"Che Ming",
""
],
[
"Li",
"Bao-An",
""
],
[
"Yong",
"Gao-Chan",
""
]
] |
0704.2341 | Artan Borici | Artan Borici | On Gauged Renormalisation Group Transformations of Lattice Fermions | 10 pages, 4 figures and 1 table | null | null | null | hep-lat cond-mat.stat-mech hep-th | null | We construct a hierarchy of lattice fermions, where the coarser lattice Dirac
operator is the Schur complement of the block UL decomposition of the finer
lattice operator. We show that the construction is an exact gauged
renormalisation group transformation of the lattice action. In particular,
using such a transformation and the QCDLAB tool, it is shown how to implement
the Ginsparg-Wilson strategy for chiral fermions in the presence of a dynamical
gauge field. The scheme allows, for the first time, a full multigrid algorithm
for lattice quarks.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 13:11:35 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Borici",
"Artan",
""
]
] |
0704.2342 | Piercarlo Bonifacio | Piercarlo Bonifacio (CIFIST, GEPI, OAT), Luca Pasquini (ESO), Paolo
Molaro (OAT), Eugenio Carretta (OABO), Patrick Fran\c{c}ois (GEPI), Raffaele
G. Gratton (OAPD), Gael James (ESO), Luca Sbordone (CIFIST, GEPI, OAT),
Fran\c{c}ois Spite (GEPI), Manuela Zoccali (DA PUC CHILE) | Variations in the lithium abundances of turn off stars in the globular
cluster 47 Tuc | recommended for publication in A&A by the managing associate Editor | null | 10.1051/0004-6361:20077227 | null | astro-ph | null | aims: Our aim is to determine Li abundances in TO stars of the Globular
Cluster 47 Tuc and test theories about Li variations among TO stars. method: We
make use of high resolution (R~ 43000), high signal-to-noise ratio (S/N=50--70)
spectra of 4 turn off (TO) stars obtained with the UVES spectrograph at the
8.2m VLT Kueyen telescope. results: The four stars observed, span the range
1.6<~A(Li)} <~ 2.14, providing a mean A(Li) = 1.84 with a standard deviation of
0.25 dex. When coupled with data of other two TO stars of the cluster,
available in the literature, the full range in Li abundances observed in this
cluster is 1.6<~A(Li)<~ 2.3. The variation in A(Li) is at least 0.6 dex (0.7
dex considering also the data available in the literature) and the scatter is
six times larger than what expected from the observational error. We claim that
these variations are real. A(Li) seems to be anti-correlated with A(Na) exactly
as observed in NGC 6752. No systematic error in our analysis could produce such
an anti-correlation. conclusions: Na production through p captures on 22Ne at
temperatures in excess of 3x10^7 K and the contemporary Li destruction could
result in this anti-correlation. However such nuclear processing cannot have
taken place in the stars themselves, which do not reach such high temperatures,
even at their centre. This points towards the processing in a previous
generation of stars. The low N/O ratios in the observed stars and the apparent
lack of correlation between N an Li abundances, place a strong constraint on
the properties of this previous generation. Our results indicate a different
behaviour among the Globular Clusters so far studied as far as the abundance
patterns are concerned.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 13:18:49 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Bonifacio",
"Piercarlo",
"",
"CIFIST, GEPI, OAT"
],
[
"Pasquini",
"Luca",
"",
"ESO"
],
[
"Molaro",
"Paolo",
"",
"OAT"
],
[
"Carretta",
"Eugenio",
"",
"OABO"
],
[
"François",
"Patrick",
"",
"GEPI"
],
[
"Gratton",
"Raffaele G.",
"",
"OAPD"
],
[
"James",
"Gael",
"",
"ESO"
],
[
"Sbordone",
"Luca",
"",
"CIFIST, GEPI, OAT"
],
[
"Spite",
"François",
"",
"GEPI"
],
[
"Zoccali",
"Manuela",
"",
"DA PUC CHILE"
]
] |
0704.2343 | Tetyana Kuzmenko | F. H. L. Essler, T. Kuzmenko, I. A. Zaliznyak | A Luttinger Liquid Coupled to a Quantum Spin Bath: Flow Equation
Approach to the Kondo Necklace Model | 10 pages, 10 figures, added figures | Phys. Rev. B 76, 115108 (2007) | 10.1103/PhysRevB.76.115108 | null | cond-mat.str-el | null | We study a lattice realization of a Luttinger liquid interacting with a bath
of quantum spins in terms of an antiferromagnetic S=1/2 Heisenberg chain, where
each spin is also coupled to a \sigma=1/2 Kondo spin degree of freedom. This
model describes the low-energy spin dynamics in quasi one dimensional
materials, where the electronic spins of the magnetic ions interact with those
of impurities, nuclei and possibly other spin species present in their
environment. For large ferromagnetic and antiferromagnetic Kondo interaction J'
there are two phases corresponding to an effective spin-1 Heisenberg chain and
a dimerised spin-1/2 ladder, respectively. For weak Kondo interaction we
establish that the Kondo interaction drives the system to a strong coupling
regime. This suggests that J'=0 is the only critical point in the system.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 15:40:29 GMT"
},
{
"version": "v2",
"created": "Fri, 22 Jun 2007 14:02:00 GMT"
}
] | 2007-09-12T00:00:00 | [
[
"Essler",
"F. H. L.",
""
],
[
"Kuzmenko",
"T.",
""
],
[
"Zaliznyak",
"I. A.",
""
]
] |
0704.2344 | Publications Ampere | Christian Vollaire (CEGELY), Laurent Nicolas (CEGELY), Alain Nicolas
(CEGELY) | Parallel computing for the finite element method | null | EUROPEAN PHYSICAL JOURNAL Applied Physics 1, 3 (03/1998) 305-314 | 10.1051/epjap:1998151 | null | cs.DC | null | A finite element method is presented to compute time harmonic microwave
fields in three dimensional configurations. Nodal-based finite elements have
been coupled with an absorbing boundary condition to solve open boundary
problems. This paper describes how the modeling of large devices has been made
possible using parallel computation, New algorithms are then proposed to
implement this formulation on a cluster of workstations (10 DEC ALPHA 300X) and
on a CRAY C98. Analysis of the computation efficiency is performed using simple
problems. The electromagnetic scattering of a plane wave by a perfect electric
conducting airplane is finally given as example.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 13:20:25 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Vollaire",
"Christian",
"",
"CEGELY"
],
[
"Nicolas",
"Laurent",
"",
"CEGELY"
],
[
"Nicolas",
"Alain",
"",
"CEGELY"
]
] |
0704.2345 | Paul Bushby | Paul J. Bushby, Steven M. Tobias | On Predicting the Solar Cycle using Mean-Field Models | 22 Pages, 5 Figures, Preprint accepted for publication in ApJ | Astrophys.J.661:1289-1296,2007 | 10.1086/516628 | null | astro-ph | null | We discuss the difficulties of predicting the solar cycle using mean-field
models. Here we argue that these difficulties arise owing to the significant
modulation of the solar activity cycle, and that this modulation arises owing
to either stochastic or deterministic processes. We analyse the implications
for predictability in both of these situations by considering two separate
solar dynamo models. The first model represents a stochastically-perturbed flux
transport dynamo. Here even very weak stochastic perturbations can give rise to
significant modulation in the activity cycle. This modulation leads to a loss
of predictability. In the second model, we neglect stochastic effects and
assume that generation of magnetic field in the Sun can be described by a fully
deterministic nonlinear mean-field model -- this is a best case scenario for
prediction. We designate the output from this deterministic model (with
parameters chosen to produce chaotically modulated cycles) as a target
timeseries that subsequent deterministic mean-field models are required to
predict. Long-term prediction is impossible even if a model that is correct in
all details is utilised in the prediction. Furthermore, we show that even
short-term prediction is impossible if there is a small discrepancy in the
input parameters from the fiducial model. This is the case even if the
predicting model has been tuned to reproduce the output of previous cycles.
Given the inherent uncertainties in determining the transport coefficients and
nonlinear responses for mean-field models, we argue that this makes predicting
the solar cycle using the output from such models impossible.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 13:22:23 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"Bushby",
"Paul J.",
""
],
[
"Tobias",
"Steven M.",
""
]
] |
0704.2346 | Marcio Rocha | M. S. Rocha, M. C. Ferreira, and O. N. Mesquita | Transition on the entropic elasticity of DNA induced by intercalating
molecules | This experimental article shows and discuss a transition observed in
the persistence length of DNA molecules when studied as a function of some
intercalating drug concentrations, like daunomycin and ethidium bromide. It
has 15 pages and 4 figures. The article presented here is in preprint format | null | 10.1063/1.2768945 | null | physics.bio-ph physics.chem-ph | null | We use optical tweezers to perform stretching experiments on DNA molecules
when interacting with the drugs daunomycin and ethidium bromide, which
intercalate the DNA molecule. These experiments are performed in the low-force
regime from zero up to 2 pN. Our results show that the persistence length of
the DNA-drug complexes increases strongly as the drug concentration increases
up to some critical value. Above this critical value, the persistence length
decreases abruptly and remains practically constant for larger drug
concentrations. The contour length of the molecules increases monotonically and
saturates as drugs concentration increases. Measured in- tercalants critical
concentrations for the persistence length transition coincide with reported
values for the helix-coil transition of DNA-drug complexes, obtained from
sedimentation experiments.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 13:38:35 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Rocha",
"M. S.",
""
],
[
"Ferreira",
"M. C.",
""
],
[
"Mesquita",
"O. N.",
""
]
] |
0704.2347 | Faisal El-Orany Dr. | Faisal A. A. El-Orany | Revival-collapse phenomenon in the quadrature squeezing of the
multiphoton Jaynes-Cummings model with the binomial states | 14 pages, 4 figures, Comments are most welcome | AnnalenPhys.17:424-432,2008 | 10.1002/andp.200710301 | null | quant-ph | null | In this paper we study the interaction between two-level atom and quantized
single-mode field, namely, Jaynes-Cummings model (JCM). The field and the atom
are initially prepared in the binomial state and the excited atomic state,
respectively. For this system we prove that the revival-collapse phenomenon
exhibited in the atomic inversion of the standard JCM can be numerically
(naturally) manifested in the evolution of the squeezing factor of the
three-photon (standard) JCM provided that the initial photon-number
distribution of the radiation has a smooth envelope.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 13:53:42 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"El-Orany",
"Faisal A. A.",
""
]
] |
0704.2348 | F. Assaoui | H. Satori, M. Harti, N. Chenfour, F. Assaoui | Bound Polaron in CuCl and GaAs Quantum Dots | 6 pages, 5 figures | null | null | null | cond-mat.other cond-mat.mtrl-sci | null | We calculated the binding energy of a polaron bound to a hydrogenic donor
impurity located in a spherical quantum dot by means of a variational and
numerical technique for finite potential models. The polaronic effect has been
considered taking into account the ion-phonon coupling under the Lee Low Pines
approach. The results show that the binding energies are drastically affected
by the dot radius, the potential barrier height and the polaronic effects.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 19:54:14 GMT"
}
] | 2009-09-29T00:00:00 | [
[
"Satori",
"H.",
""
],
[
"Harti",
"M.",
""
],
[
"Chenfour",
"N.",
""
],
[
"Assaoui",
"F.",
""
]
] |
0704.2349 | Katsumi Itoh | Yuji Igarashi, Katsumi Itoh and Hidenori Sonoda | Quantum Master Equation for QED in Exact Renormalization Group | 15 pages, no figure | Prog.Theor.Phys.118:121-134,2007 | 10.1143/PTP.118.121 | null | hep-th | null | Recently, one of us (H.S.) gave an explicit form of the Ward-Takahashi
identity for the Wilson action of QED. We first rederive the identity using a
functional method. The identity makes it possible to realize the gauge symmetry
even in the presence of a momentum cutoff. In the cutoff dependent realization,
the abelian nature of the gauge symmetry is lost, breaking the nilpotency of
the BRS transformation. Using the Batalin-Vilkovisky formalism, we extend the
Wilson action by including the antifield contributions. Then, the
Ward-Takahashi identity for the Wilson action is lifted to a quantum master
equation, and the modified BRS transformation regains nilpotency. We also
obtain a flow equation for the extended Wilson action.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 14:01:32 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Igarashi",
"Yuji",
""
],
[
"Itoh",
"Katsumi",
""
],
[
"Sonoda",
"Hidenori",
""
]
] |
0704.2350 | Amedeo Balbi | A. Balbi, C. Quercellini | The time evolution of cosmological redshift as a test of dark energy | 9 pages, 2 figures. Matching published version | null | 10.1111/j.1365-2966.2007.12407.x | null | astro-ph | null | The variation of the expansion rate of the Universe with time produces an
evolution in the cosmological redshift of distant sources (for example quasar
Lyman-$\alpha$ absorption lines), that might be directly observed by future
ultra stable, high-resolution spectrographs (such as CODEX) coupled to
extremely large telescopes (such as European Southern Observatory's Extremely
Large Telescope, ELT). This would open a new window to explore the physical
mechanism responsible for the current acceleration of the Universe. We
investigate the evolution of cosmological redshift from a variety of dark
energy models, and compare it with simulated data. We perform a Fisher matrix
analysis and discuss the prospects for constraining the parameters of these
models and for discriminating among competing candidates. We find that, because
of parameter degeneracies, and of the inherent technical difficulties involved
in this kind of observations, the uncertainties on parameter reconstruction can
be rather large unless strong external priors are assumed. However, the method
could be a valuable complementary cosmological tool, and give important
insights on the dynamics of dark energy, not obtainable using other probes.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 14:16:33 GMT"
},
{
"version": "v2",
"created": "Mon, 3 Sep 2007 09:58:23 GMT"
},
{
"version": "v3",
"created": "Mon, 12 Nov 2007 17:59:59 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Balbi",
"A.",
""
],
[
"Quercellini",
"C.",
""
]
] |
0704.2351 | Giorgi Pascal | Jean-Guillaume Dumas (LMC - IMAG), Philippe Elbaz-Vincent (I3M),
Pascal Giorgi (LP2A), Anna Urbanska (LMC - IMAG) | Parallel computation of the rank of large sparse matrices from algebraic
K-theory | null | null | null | null | math.KT cs.DC cs.SC math.NT | null | This paper deals with the computation of the rank and of some integer Smith
forms of a series of sparse matrices arising in algebraic K-theory. The number
of non zero entries in the considered matrices ranges from 8 to 37 millions.
The largest rank computation took more than 35 days on 50 processors. We report
on the actual algorithms we used to build the matrices, their link to the
motivic cohomology and the linear algebra and parallelizations required to
perform such huge computations. In particular, these results are part of the
first computation of the cohomology of the linear group GL_7(Z).
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 14:29:28 GMT"
},
{
"version": "v2",
"created": "Tue, 24 Apr 2007 15:28:48 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Dumas",
"Jean-Guillaume",
"",
"LMC - IMAG"
],
[
"Elbaz-Vincent",
"Philippe",
"",
"I3M"
],
[
"Giorgi",
"Pascal",
"",
"LP2A"
],
[
"Urbanska",
"Anna",
"",
"LMC - IMAG"
]
] |
0704.2352 | Alain Gelle | Alain Gell\'e (EPFL), Andreas L\"auchli (IRMA), Brijesh Kumar,
Fr\'ed\'eric Mila (EPFL) | A 2D quantum antiferromagnet with a four-fold degenerate
valence-bond-solid ground state | null | null | 10.1103/PhysRevB.77.014419 | null | quant-ph cond-mat.str-el | null | We study the competition between antiferromagnetic order and valence bond
solid formation in a two-dimensional frustrated spin-1/2 model. The J1-J2 model
on the square lattice is further frustrated by introducing products of
three-spin projectors which stabilize four dimer-product states as degenerate
ground states. These four states are reminiscent of the dimerized singlet
ground state of the Shastry-Sutherland model. Using exact diagonalizations, we
study the evolution of the ground state by varying theratio of interactions.
For a large range of parameters (J2 > 0.25J1), our model shows a direct
transition between the valence-bond-solid phase and the collinear
antiferromagnetic phase. For small values of J2, several intermediate phases
appear which are also analyzed.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 14:34:25 GMT"
}
] | 2013-05-29T00:00:00 | [
[
"Gellé",
"Alain",
"",
"EPFL"
],
[
"Läuchli",
"Andreas",
"",
"IRMA"
],
[
"Kumar",
"Brijesh",
"",
"EPFL"
],
[
"Mila",
"Frédéric",
"",
"EPFL"
]
] |
0704.2353 | Natasha Devroye | Mai Vu, Natasha Devroye, Masoud Sharif and Vahid Tarokh | Scaling Laws of Cognitive Networks | significantly revised and extended, 30 pages, 13 figures, submitted
to IEEE Journal of Special Topics in Signal Processing | null | 10.1109/CROWNCOM.2007.4549764 | null | cs.IT math.IT | null | We consider a cognitive network consisting of n random pairs of cognitive
transmitters and receivers communicating simultaneously in the presence of
multiple primary users. Of interest is how the maximum throughput achieved by
the cognitive users scales with n. Furthermore, how far these users must be
from a primary user to guarantee a given primary outage. Two scenarios are
considered for the network scaling law: (i) when each cognitive transmitter
uses constant power to communicate with a cognitive receiver at a bounded
distance away, and (ii) when each cognitive transmitter scales its power
according to the distance to a considered primary user, allowing the cognitive
transmitter-receiver distances to grow. Using single-hop transmission, suitable
for cognitive devices of opportunistic nature, we show that, in both scenarios,
with path loss larger than 2, the cognitive network throughput scales linearly
with the number of cognitive users. We then explore the radius of a primary
exclusive region void of cognitive transmitters. We obtain bounds on this
radius for a given primary outage constraint. These bounds can help in the
design of a primary network with exclusive regions, outside of which cognitive
users may transmit freely. Our results show that opportunistic secondary
spectrum access using single-hop transmission is promising.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 15:57:37 GMT"
},
{
"version": "v2",
"created": "Wed, 24 Oct 2007 20:56:38 GMT"
}
] | 2016-11-18T00:00:00 | [
[
"Vu",
"Mai",
""
],
[
"Devroye",
"Natasha",
""
],
[
"Sharif",
"Masoud",
""
],
[
"Tarokh",
"Vahid",
""
]
] |
0704.2354 | Marie Rastello | Marie Rastello | A study of the size of snow particles in powder snow avalanches | null | Annals of Glaciology 32 (2001) 258-262 | null | null | physics.class-ph | null | In this work, we study the size of the particles involved in a powder snow
avalanche phenomenon. To determine these sizes, we study all the phenomena the
particles have to face before arriving in the "body" of the avalanche. We study
the boundary layer which is at the bottom of the avalanche. We determine, with
the help of experimental data, the range of size of the particles that can be
entrained by the avalanche. We then examine the possibility for these particles
to reach the top of the boundary layer, and so to take part in the avalanche.
Our final result is that the more frequent particles suspended in a powder snow
avalanche have a size lower than 200 micrometers.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 14:37:46 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Rastello",
"Marie",
""
]
] |
0704.2355 | Luigi Santocanale | Luigi Santocanale (LIF) | A Nice Labelling for Tree-Like Event Structures of Degree 3 | null | null | null | null | cs.DC | null | We address the problem of finding nice labellings for event structures
of degree 3. We develop a minimum theory by which we prove that the labelling
number of an event structure of degree 3 is bounded by a linear function of the
height. The main theorem we present in this paper states that event structures
of degree 3 whose causality order is a tree have a nice labelling with 3
colors. Finally, we exemplify how to use this theorem to construct upper bounds
for the labelling number of other event structures of degree 3.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 14:39:09 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Santocanale",
"Luigi",
"",
"LIF"
]
] |
0704.2356 | Philippe Vergne | Chaomleffel Jean Pierre (LaMCoS), Dalmaz G\'erard (LaMCoS), Philippe
Vergne (LaMCoS) | Experimental Results and Analytical Predictions of EHL Film Thickness | null | 33rd Leeds Lyon Symposium on Tribology "Tribology at the
Interface", Royaume-Uni (12/09/2006) | null | null | physics.class-ph | null | In this work, we consider several types of lubricants - including
non-Newtonian fluids - that were studied under various operating conditions
leading us to explore a wide range of dimensionless parameters. The
experimental results are compared with predictions given by the usual
analytical EHL relationships and by more recently developed models. This broad
comparison conducted with particular emphasis on minimum film thickness (hm)
showed a fair agreement between experimental data and a few predictions
including some obtained from extended models. Commonly used elasto-hydrodynamic
lubrication (EHL) models did not systematically gave accurate hm estimation,
whereas minimum film thickness not only is a yield value but also serves as a
key parameter in estimating lubrication regimes.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 14:39:14 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Pierre",
"Chaomleffel Jean",
"",
"LaMCoS"
],
[
"Gérard",
"Dalmaz",
"",
"LaMCoS"
],
[
"Vergne",
"Philippe",
"",
"LaMCoS"
]
] |
0704.2357 | El Houcein El Abdalaoui | El Houcein El Abdalaoui (LMRS) | A new class of rank one transformations with singular spectrum | 16 pages et 27 r\'ef\'erences | null | null | null | math.DS | null | We introduce a new tool to study the spectral type of rank one
transformations using the method of central limit theorem for trigonometric
sums. We get some new applications.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 14:40:00 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Abdalaoui",
"El Houcein El",
"",
"LMRS"
]
] |
0704.2358 | Jan C. Hammer | J.C. Hammer, J.C. Cuevas, F.S. Bergeret, W. Belzig | Density of states and supercurrent in diffusive SNS junctions: role of
nonideal interfaces and spin-flip scattering | 12 pages, 13 figures | Phys. Rev. B 76, 064514 (2007). | 10.1103/PhysRevB.76.064514 | null | cond-mat.supr-con cond-mat.mes-hall | null | We present a theoretical study of the density of states and supercurrent in
diffusive superconductor-normal metal-superconductor (SNS) junctions. In
particular, we study the influence on these two equilibrium properties of both
an arbitrary transparency of the SN interfaces and the presence of spin-flip
scattering in the normal wire. We show that the minigap that is present in the
spectrum of the diffusive wire is very sensitive to the interface transmission.
More mportantly, we show that at arbitrary transparency the minigap replaces
the Thouless energy as the relevant energy scale for the proximity effect,
determining for instance the temperature dependence of the critical current. We
also study in detail how the critical current is suppressed by the effect of
spin-flip scattering, which can be due to either magnetic impurities or, under
certain circumstances, to an external magnetic field. Our analysis based on the
quasiclassical theory of diffusive superconductors can be very valuable to
establish quantitative comparisons between experiment and theory.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 14:43:03 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Hammer",
"J. C.",
""
],
[
"Cuevas",
"J. C.",
""
],
[
"Bergeret",
"F. S.",
""
],
[
"Belzig",
"W.",
""
]
] |
0704.2359 | Marc Odunlami | Ch\'erif Amrouche (LMA - Pau), Macaire Batchi (LMA - Pau, Latep), Jean
Batina (LATEP) | Navier-Stokes equations with periodic boundary conditions and pressure
loss | 10 pages | null | null | null | math.AP | null | We present in this note the existence and uniqueness results for the Stokes
and Navier-Stokes equations which model the laminar flow of an incompressible
fluid inside a two-dimensional channel of periodic sections. The data of the
pressure loss coefficient enables us to establish a relation on the pressure
and to thus formulate an equivalent problem.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 14:43:07 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Amrouche",
"Chérif",
"",
"LMA - Pau"
],
[
"Batchi",
"Macaire",
"",
"LMA - Pau, Latep"
],
[
"Batina",
"Jean",
"",
"LATEP"
]
] |
0704.2360 | Marc Odunlami | Ch\'erif Amrouche (LMA - Pau), Macaire Batchi (LMA - Pau, Latep), Jean
Batina (LATEP) | Reproductive strong solutions of Navier-Stokes equations with non
homogeneous boundary conditions | 18 pages | null | null | null | math.AP | null | The object of the present paper is to show the existence and the uniqueness
of a reproductive strong solution of the Navier-Stokes equations, i.e. the
solution $\boldsymbol{u} $ belongs to $\text{}\mathbf{L}% ^{\infty}(0,T;V) \cap
\mathbf{L}^{2}(0,T;\mathbf{H}% ^{2}(\Omega))$ and satisfies the property
$\boldsymbol{u}% (\boldsymbol{x,}T) =\boldsymbol{u}% (\boldsymbol{x,}0)
=\boldsymbol{u}_{0}(\boldsymbol{x})$. One considers the case of an
incompressible fluid in two dimensions with nonhomogeneous boundary conditions,
and external forces are neglected.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 14:47:18 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Amrouche",
"Chérif",
"",
"LMA - Pau"
],
[
"Batchi",
"Macaire",
"",
"LMA - Pau, Latep"
],
[
"Batina",
"Jean",
"",
"LATEP"
]
] |
0704.2361 | Marc Odunlami | Ch\'erif Amrouche (LMA - Pau), Macaire Batchi (LMA - Pau, Latep), Jean
Batina (LATEP) | Solutions fortes de l'\'equation de l'\'energie | 9 pages | null | null | null | math.AP | null | In this paper, we give some existence results of stong solutions for the
energy equation associated to the Navier-Stokes equations with nonhomogeneous
boundary conditions in two dimension.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 14:48:19 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Amrouche",
"Chérif",
"",
"LMA - Pau"
],
[
"Batchi",
"Macaire",
"",
"LMA - Pau, Latep"
],
[
"Batina",
"Jean",
"",
"LATEP"
]
] |
0704.2362 | Athanasios Batakis | Athanasios Batakis (MAPMO), Pierre Levitz (PMC), Michel Zinsmeister
(PMC, MAPMO) | On Brownian flights | null | Pure & Applied Mathematics Quarterly (2011) Vol. 7, 1, pg 85-105 | null | null | math.CA | null | Let K be a compact subset of ${\mathbb R}^n$. We choose at random with
uniform law a point at distance $\epsilon$ of K and start a Brownian motion
(BM) from this point. We study the probability that this BM hits K for the
first time at a distance $\geq r$ from the starting point.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 14:49:45 GMT"
}
] | 2019-04-22T00:00:00 | [
[
"Batakis",
"Athanasios",
"",
"MAPMO"
],
[
"Levitz",
"Pierre",
"",
"PMC"
],
[
"Zinsmeister",
"Michel",
"",
"PMC, MAPMO"
]
] |
0704.2363 | Marc Odunlami | Ch\'erif Amrouche (LMA - PAU), El-Hacene E.H Ouazar | Energy solutions for polymer aqueous solutions in two dimension | 20 pages | null | null | null | math.AP | null | The aim of this article is to study a nonlinear system modeling a
Non-Newtonian fluid of polymer aqueous solutions. We are interested here in the
existence of weak solutions for the stationary problem in a bounded plane
domain or in two-dimensional exterior domain. Due to the third order of
derivatives in the non-linear term, it's difficult to obtain solution
satisfying energy inequality. But with a good choice of boundary conditions, an
adapt special basis and the use of the good properties of the trilinear form
associated to the non-linear term, we obtain energy solutions. The problem in
bounded domain is treated and the more difficult problem on non bounded domain
too.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 14:51:47 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Amrouche",
"Chérif",
"",
"LMA - PAU"
],
[
"Ouazar",
"El-Hacene E. H",
""
]
] |
0704.2364 | Alain Corfdir | Alain Corfdir (ENPC-Cermes) | Yield design formulation for porous media subjected to flow, using
approximate pressure field. Calcul \`a la rupture en pr\'esence d'un
\'ecoulement : formulation cin\'ematique avec un champ de pression approch\'e | null | Comptes rendus - M\'ecanique 334, 3 (2006) 176-182 | 10.1016/j.crme.2006.01.009 | null | physics.class-ph | null | Yield design formulation for porous media subjected to flow, using
approximate pressure field. We attempt here to use the kinematic method of
yield design in the case of a porous medium subjected to flow (with or without
free surface), without looking for the exact solution of the pressure field.
The method proposed here is based on the use of approximate pressure fields. In
this paper, we show how, under different conditions concerning the yield
criterion and the velocity field, the use of such approximate fields allows to
obtain a necessary condition for stability without having to find the real
pressure field. Nous cherchons ici \`a utiliser la m\'ethode cin\'ematique du
calcul \`a la rupture dans le cas d'un milieu poreux soumis \`a un \'ecoulement
avec ou sans surface libre sans conna\^itre la solution exacte du champ de
pression. La m\'ethode propos\'ee ici repose sur l'utilisation de champs de
pression approch\'es par d\'efaut. Nous montrerons comment sous certaines
conditions portant sur le crit\`ere de r\'esistance et sur le champ de vitesse
utilis\'e, l'utilisation de tels champs de pression approch\'es permet
d'obtenir une condition n\'ecessaire de stabilit\'e sans avoir \`a d\'eterminer
exactement l'\'ecoulement.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 14:54:52 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Corfdir",
"Alain",
"",
"ENPC-Cermes"
]
] |
0704.2365 | Takeyasu Ito | Takeyasu M. Ito | Neutron Beta Decay: Status and Future of the Asymmetry Measurement | Contributed to 4th International Workshop on the CKM Unitarity
Triangle (CKM 2006), Nagoya, Japan, 12-16 Dec 2006 | null | null | LA-UR 072229 | nucl-ex hep-ex | null | With more intense sources of cold and ultracold neutrons becoming available
and with improved experimental techniques being developed, determination of
|Vud| from neutron beta decay with a similar precision to that from from
superallowed beta decays is within reach. Determination of |Vud| from neutron
beta decay, free from nuclear corrections, hold the most promise for a further
improvement of the determination of |Vud|. The current and future neutron beta
decay correlation experiments including the UCNA experiment at Los Alamos
National Laboratory are reviewed
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 15:19:57 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Ito",
"Takeyasu M.",
""
]
] |
0704.2366 | Publications Ampere | Laurent Nicolas (CEGELY), M. Furstoss (LMFA), Marie-Annick Galland
(LMFA) | Analogy electromagnetism-acoustics: Validation and application to local
impedance active control for sound absorption | null | EUROPEAN PHYSICAL JOURNAL Applied Physics 4, 1 (10/1998) 95-100 | 10.1051/epjap:1998247 | null | physics.class-ph | null | An analogy between electromagnetism and acoustics is presented in 2D. The
propagation of sound in presence of absorbing material is modeled using an open
boundary microwave package. Validation is performed through analytical and
experimental results. Application to local impedance active control for free
field sound absorption is finally described.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 15:55:34 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Nicolas",
"Laurent",
"",
"CEGELY"
],
[
"Furstoss",
"M.",
"",
"LMFA"
],
[
"Galland",
"Marie-Annick",
"",
"LMFA"
]
] |
0704.2367 | Yusuke Sasano | Yusuke Sasano | Coupled Painlev\'e VI systems in dimension four with affine Weyl group
symmetry of type $D_6^{(1)}$, II | 14 pages, 5 figures | RIMS Kokyuroku Bessatsu B5 (2008), 137-152 | null | null | math.AG | null | We give a reformulation of a six-parameter family of coupled Painlev\'e VI
systems with affine Weyl group symmetry of type $D_6^{(1)}$ from the viewpoint
of its symmetry and holomorphy properties.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 15:32:40 GMT"
},
{
"version": "v2",
"created": "Thu, 21 Jun 2007 12:02:19 GMT"
},
{
"version": "v3",
"created": "Tue, 26 Jun 2007 11:52:57 GMT"
},
{
"version": "v4",
"created": "Wed, 18 Jul 2007 01:52:11 GMT"
}
] | 2010-11-04T00:00:00 | [
[
"Sasano",
"Yusuke",
""
]
] |
0704.2368 | Nikolay Achasov | N. N. Achasov and G. N. Shestakov | Lightest scalar in the SU_L(2)*SU_R(2) linear \sigma model | 10 pages, 3 figures, English improved, PACS numbers changed, two
Refs. added, E-mail addresses removed and Ref. [1] shortened for the overrun
of the article length allowable in Phys. Rev. Lett | Phys.Rev.Lett.99:072001,2007 | 10.1103/PhysRevLett.99.072001 | null | hep-ph hep-ex nucl-th | null | We consider the lightest scalar meson in the frame of the $SU_L(2)\times
SU_R(2)$ linear $\sigma$ model, keeping in mind that this model could be the
low energy realization of the two-flavour QCD. We show that the $\sigma$ field
is described by its four-quark component at least in the $\sigma$ resonance
energy (virtuality) region and the $\sigma\to\gamma\gamma$ decay is the four
quark transition.
We emphasize that residues of the $\sigma$ pole in the $\pi\pi\to\pi\pi$ and
$\gamma\gamma\to\pi\pi$ amplitudes do not give an idea about the $\sigma$ meson
nature, and the progress in studying the $\sigma$ meson production mechanisms
in different processes could essentially further us in understanding its
nature.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 15:39:18 GMT"
},
{
"version": "v2",
"created": "Sat, 18 Aug 2007 07:14:39 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Achasov",
"N. N.",
""
],
[
"Shestakov",
"G. N.",
""
]
] |
0704.2369 | Cesare Tronci | Darryl D. Holm, Vakhtang Putkaradze, Cesare Tronci | Geometric gradient-flow dynamics with singular solutions | 28 pages, 1 figure, to appear on Physica D | null | 10.1016/j.physd.2008.04.010 | null | nlin.AO nlin.PS | null | The gradient-flow dynamics of an arbitrary geometric quantity is derived
using a generalization of Darcy's Law. We consider flows in both Lagrangian and
Eulerian formulations. The Lagrangian formulation includes a dissipative
modification of fluid mechanics. Eulerian equations for self-organization of
scalars, 1-forms and 2-forms are shown to reduce to nonlocal characteristic
equations. We identify singular solutions of these equations corresponding to
collapsed (clumped) states and discuss their evolution.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 15:49:34 GMT"
},
{
"version": "v2",
"created": "Mon, 28 Apr 2008 10:45:34 GMT"
}
] | 2008-04-28T00:00:00 | [
[
"Holm",
"Darryl D.",
""
],
[
"Putkaradze",
"Vakhtang",
""
],
[
"Tronci",
"Cesare",
""
]
] |
0704.2370 | Jean-Louis Pichard | Axel Freyn (SPEC), Jean-Louis Pichard (SPEC) | Effect of flux-dependent Friedel oscillations upon the effective
transmission of an interacting nano-system | null | European Physical Journal B 58 (2007) 279-290 | 10.1140/epjb/e2007-00233-1 | null | cond-mat.mes-hall | null | We consider a nano-system connected to measurement probes via non interacting
leads. When the electrons interact inside the nano-system, the coefficient
|ts(E_F)|^2 describing its effective transmission at the Fermi energy E_F
ceases to be local. This effect of electron-electron interactions upon
|ts(E_F)|^2 is studied using a one dimensional model of spinless fermions and
the Hartree-Fock approximation. The non locality of |ts(E_F)|^2 is due to the
coupling between the Hartree and Fock corrections inside the nano-system and
the scatterers outside the nano-system via long range Friedel oscillations.
Using this phenomenon, one can vary |ts(E_F)|^2 by an Aharonov-Bohm flux
threading a ring which is attached to one lead at a distance Lc from the
nano-system. For small distances Lc, the variation of the quantum conductance
induced by this non local effect can exceed 0.1 (e^2/h).
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 15:42:24 GMT"
}
] | 2011-11-09T00:00:00 | [
[
"Freyn",
"Axel",
"",
"SPEC"
],
[
"Pichard",
"Jean-Louis",
"",
"SPEC"
]
] |
0704.2371 | Yakup Hundur | Yakup Hundur, Rainer Hippler and Ziya B. Guvenc | Molecular Dynamics Study of a Thermal Expansion Coefficient: Ti Bulk
with an Elastic Minimum Image Method | 4 pages, 3 figures | Chin. Phys. Lett. 23 (2006), 1068-1071 | null | null | physics.comp-ph physics.atm-clus | null | Linear thermal expansion coefficient (TEC) and specific heat of Ti bulk is
investigated by means of molecular dynamics simulation. Elastic Minimum Image
Convention of periodic boundary conditions is introduced to allow the bulk to
adjust its size according to the new temporarily fixed temperature. The TEC and
the specific heat of Ti are compared to the available theoretical and
experimental data.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 15:47:17 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Hundur",
"Yakup",
""
],
[
"Hippler",
"Rainer",
""
],
[
"Guvenc",
"Ziya B.",
""
]
] |
0704.2372 | Jean Dolbeault | Adrien Blanchet, Matteo Bonforte, Jean Dolbeault (CEREMADE), Gabriele
Grillo, Juan-Luis V\'azquez | Asymptotics of the fast diffusion equation via entropy estimates | null | null | 10.1007/s00205-008-0155-z | null | math.AP | null | We consider non-negative solutions of the fast diffusion equation $u_t=\Delta
u^m$ with $m \in (0,1)$, in the Euclidean space R^d, d?3, and study the
asymptotic behavior of a natural class of solutions, in the limit corresponding
to $t\to\infty$ for $m\ge m_c=(d-2)/d$, or as t approaches the extinction time
when m < mc. For a class of initial data we prove that the solution converges
with a polynomial rate to a self-similar solution, for t large enough if $m\ge
m_c$, or close enough to the extinction time if m < mc. Such results are new in
the range $m\le m_c$ where previous approaches fail. In the range mc < m < 1 we
improve on known results.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 15:54:24 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Blanchet",
"Adrien",
"",
"CEREMADE"
],
[
"Bonforte",
"Matteo",
"",
"CEREMADE"
],
[
"Dolbeault",
"Jean",
"",
"CEREMADE"
],
[
"Grillo",
"Gabriele",
""
],
[
"Vázquez",
"Juan-Luis",
""
]
] |
0704.2373 | Sadhan Adhikari K | Sadhan K. Adhikari and Luca Salasnich | Mixing-demixing transition and collapse of a vortex state in a
quasi-two-dimensional boson-fermion mixture | 9 pages, 11 figures | Phys. Rev. A 75 (2007) 053603 (p1-9) | 10.1103/PhysRevA.75.053603 | null | cond-mat.other | null | We investigate the mixing-demixing transition and the collapse in a
quasi-two-dimensional degenerate boson-fermion mixture (DBFM) with a bosonic
vortex. We solve numerically a quantum-hydrodynamic model based on a new
density functional which accurately takes into account the dimensional
crossover. It is demonstrated that with the increase of interspecies repulsion,
a mixed state of DBFM could turn into a demixed state. The system collapses for
interspecies attraction above a critical value which depends on the vortex
quantum number. For interspecies attraction just below this critical limit
there is almost complete mixing of boson and fermion components. Such mixed and
demixed states of a DBFM could be experimentally realized by varying an
external magnetic field near a boson-fermion Feshbach resonance, which will
result in a continuous variation of interspecies interaction.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 16:02:53 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Adhikari",
"Sadhan K.",
""
],
[
"Salasnich",
"Luca",
""
]
] |
0704.2374 | Daniel Fraiman | Daniel Fraiman | Growing Directed Networks: Estimation and Hypothesis Testing | 4 pages, 3 figures | null | null | null | physics.soc-ph physics.data-an | null | Based only on the information gathered in a snapshot of a directed network,
we present a formal way of checking if the proposed model is correct for the
empirical growing network under study. In particular, we show how to estimate
the attractiveness, and present an application of the model presented in
[arxiv:0704.1847] to the scientific publications network from the ISI dataset.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 16:08:32 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Fraiman",
"Daniel",
""
]
] |
0704.2375 | Stefano Buzzi | Stefano Buzzi and H. Vincent Poor | Power control algorithms for CDMA networks based on large system
analysis | To appear in the Proceedings of the 2007 IEEE International Symposium
on Information Theory, Nice, France, June 24 - 29, 2007 | null | null | null | cs.IT math.IT | null | Power control is a fundamental task accomplished in any wireless cellular
network; its aim is to set the transmit power of any mobile terminal, so that
each user is able to achieve its own target SINR. While conventional power
control algorithms require knowledge of a number of parameters of the signal of
interest and of the multiaccess interference, in this paper it is shown that in
a large CDMA system much of this information can be dispensed with, and
effective distributed power control algorithms may be implemented with very
little information on the user of interest. An uplink CDMA system subject to
flat fading is considered with a focus on the cases in which a linear MMSE
receiver and a non-linear MMSE serial interference cancellation receiver are
adopted; for the latter case new formulas are also given for the system SINR in
the large system asymptote. Experimental results show an excellent agreement
between the performance and the power profile of the proposed distributed
algorithms and that of conventional ones that require much greater prior
knowledge.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 16:12:59 GMT"
}
] | 2007-07-13T00:00:00 | [
[
"Buzzi",
"Stefano",
""
],
[
"Poor",
"H. Vincent",
""
]
] |
0704.2376 | Ta\'ise Oliveira Dr. | Taise Santiago Costa Oliveira | Catalan Traffic and Integrals on the Grassmannians of Lines | Excerpt from my Ph.D. Thesis; to appear on "Discrete Mathematics" | Discrete Mathematics, Volume 308, number 1, pp 148-152, 2008 | 10.1016/j.disc.2007.03.085 | null | math.AG | null | We prove that certain numbers occurring in a problem of paths enumeration,
studied by Niederhausen (Catlan Traffic at the Beach, The Electronic Journal of
Combinatorics, 9, (2002), 1--17), are top intersection numbers in the
cohomology ring of the grassmannians of the lines in the complex projective
(n+1)-space.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 16:13:12 GMT"
}
] | 2009-04-16T00:00:00 | [
[
"Oliveira",
"Taise Santiago Costa",
""
]
] |
0704.2377 | Andreas Leopold Knutsen | Andreas Leopold Knutsen | A note on Seshadri constants on general $K3$ surfaces | 3 pages | null | null | null | math.AG | null | We prove a lower bound on the Seshadri constant $\epsilon (L)$ on a $K3$
surface $S$ with $\Pic S \simeq \ZZ[L]$. In particular, we obtain that
$\epsilon (L)=\alpha$ if $L^2=\alpha^2$ for an integer $\alpha$.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 16:25:00 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Knutsen",
"Andreas Leopold",
""
]
] |
0704.2378 | Jason Bell | Jason P. Bell and Agata Smoktunowicz | Extended centres of finitely generated prime algebras | 17 pages | null | null | null | math.RA | null | Let $K$ be a field and let $A$ be a finitely generated prime $K$-algebra. We
generalize a result of Smith and Zhang, showing that if $A$ is not PI and does
not have a locally nilpotent ideal, then the extended centre of $A$ has
transcendence degree at most ${\rm GKdim}(A)-2$ over $K$. As a consequence, we
are able to show that if $A$ is a prime $K$-algebra of quadratic growth, then
either the extended centre is a finite extension of K or $A$ is PI. Finally, we
give an example of a finitely generated non-PI prime $K$-algebra of GK
dimension 2 with a locally nilpotent ideal such that the extended centre has
infinite transcendence degree over $K$.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 16:20:32 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Bell",
"Jason P.",
""
],
[
"Smoktunowicz",
"Agata",
""
]
] |
0704.2379 | Jose A. Cuesta | Jose A. Capitan and Jose A. Cuesta | Fundamental-measure density functional for the fluid of aligned hard
hexagons: New insights in fundamental measure theory | 10 pages, 9 figures, uses RevTeX4 | Phys. Rev. E 76, 011403 (2007) | 10.1103/PhysRevE.76.011403 | null | cond-mat.soft cond-mat.stat-mech | null | In this article we obtain a fundamental measure functional for the model of
aligned hard hexagons in the plane. Our aim is not just to provide a functional
for a new, admittedly academic, model, but to investigate the structure of
fundamental measure theory. A model of aligned hard hexagons has similarities
with the hard disk model. Both share "lost cases", i.e. admit configurations of
three particles in which there is pairwise overlap but not triple overlap.
These configurations are known to be problematic for fundamental measure
functionals, which are not able to capture their contribution correctly. This
failure lies in the inability of these functionals to yield a correct low
density limit of the third order direct correlation function. Here we derive
the functional by projecting aligned hard cubes on the plane x+y+z=0. The
correct dimensional crossover behavior of these functionals permits us to
follow this strategy. The functional of aligned hard cubes, however, does not
have lost cases, so neither had the resulting functional for aligned hard
hexagons. The latter exhibits, in fact, a peculiar structure as compared to the
one for hard disks. It depends on a uniparametric family of weighted densities
through a new term not appearing in the functional for hard disks. Apart from
studying the freezing of this system, we discuss the implications of the
functional structure for new developments of fundamental measure theory.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 16:22:05 GMT"
}
] | 2007-11-26T00:00:00 | [
[
"Capitan",
"Jose A.",
""
],
[
"Cuesta",
"Jose A.",
""
]
] |
0704.2380 | Carlo Marinelli | Carlo Marinelli | Local well-posedness of Musiela's SPDE with L\'evy noise | Final version | null | null | null | math.PR | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We determine sufficient conditions on the volatility coefficient of Musiela's
stochastic partial differential equation driven by an infinite dimensional
L{\'e}vy process so that it admits a unique local mild solution in spaces of
functions whose first derivative is square integrable with respect to a weight.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 16:23:19 GMT"
},
{
"version": "v2",
"created": "Fri, 22 Aug 2008 18:15:59 GMT"
}
] | 2008-08-22T00:00:00 | [
[
"Marinelli",
"Carlo",
""
]
] |
0704.2381 | Jason Bell | Jason P. Bell and Agata Smoktunowicz | The prime spectrum of algebras of quadratic growth | 23 pages | null | null | null | math.RA | null | We study prime algebras of quadratic growth. Our first result is that if $A$
is a prime monomial algebra of quadratic growth then $A$ has finitely many
prime ideals $P$ such that $A/P$ has GK dimension one. This shows that prime
monomial algebras of quadratic growth have bounded matrix images. We next show
that a prime graded algebra of quadratic growth has the property that the
intersection of the nonzero prime ideals $P$ such that $A/P$ has GK dimension 2
is non-empty, provided there is at least one such ideal. From this we conclude
that a prime monomial algebra of quadratic growth is either primitive or has
nonzero locally nilpotent Jacobson radical. Finally, we show that there exists
a prime monomial algebra $A$ of GK dimension two with unbounded matrix images
and thus the quadratic growth hypothesis is necessary to conclude that there
are only finitely many prime ideals such that $A/P$ has GK dimension 1.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 16:27:56 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Bell",
"Jason P.",
""
],
[
"Smoktunowicz",
"Agata",
""
]
] |
0704.2382 | Balint C. Toth | Z. Fodor (1 and 2 and 3), K. K. Szabo (1), B. C. Toth (1 and 2) ((1)
University of Wuppertal, (2) Eotvos University, (3) University of California,
San Diego) | Hadron spectroscopy from canonical partition functions | 13 pages, 4 figures. Spelling and grammatical errors are corrected | JHEP0708:092,2007 | 10.1088/1126-6708/2007/08/092 | ITP-Budapest 632 | hep-lat | null | A spectroscopic method for staggered fermions based on thermodynamical
considerations is proposed. The canonical partition functions corresponding to
the different quark number sectors are expressed in the low temperature limit
as polynomials of the eigenvalues of the reduced fermion matrix. Taking the
zero temperature limit yields the masses of the lowest states. The method is
successfully applied to the Goldstone pion and both dynamical and quenched
results are presented showing good agreement with that of standard
spectroscopy. Though in principle the method can be used to obtain the baryon
and dibaryon masses, due to their high computational costs such calculations
are practically unreachable.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 16:28:23 GMT"
},
{
"version": "v2",
"created": "Tue, 7 Aug 2007 11:14:58 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Fodor",
"Z.",
"",
"1 and 2 and 3"
],
[
"Szabo",
"K. K.",
"",
"1 and 2"
],
[
"Toth",
"B. C.",
"",
"1 and 2"
]
] |
0704.2383 | Stefano Buzzi | Stefano Buzzi, Valeria Massaro, and H. Vincent Poor | Power control and receiver design for energy efficiency in multipath
CDMA channels with bandlimited waveforms | appeared in the Proceedings of the 41st Annual Conference on
Information Sciences and Systems, John Hopkins University, March 2007 | null | null | null | cs.IT math.IT | null | This paper is focused on the cross-layer design problem of joint multiuser
detection and power control for energy-efficiency optimization in a wireless
data network through a game-theoretic approach. Building on work of Meshkati,
et al., wherein the tools of game-theory are used in order to achieve
energy-efficiency in a simple synchronous code division multiple access system,
system asynchronism, the use of bandlimited chip-pulses, and the multipath
distortion induced by the wireless channel are explicitly incorporated into the
analysis. Several non-cooperative games are proposed wherein users may vary
their transmit power and their uplink receiver in order to maximize their
utility, which is defined here as the ratio of data throughput to transmit
power. In particular, the case in which a linear multiuser detector is adopted
at the receiver is considered first, and then, the more challenging case in
which non-linear decision feedback multiuser detectors are employed is
considered. The proposed games are shown to admit a unique Nash equilibrium
point, while simulation results show the effectiveness of the proposed
solutions, as well as that the use of a decision-feedback multiuser receiver
brings remarkable performance improvements.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 16:35:59 GMT"
}
] | 2015-03-13T00:00:00 | [
[
"Buzzi",
"Stefano",
""
],
[
"Massaro",
"Valeria",
""
],
[
"Poor",
"H. Vincent",
""
]
] |
0704.2384 | Michael Cuntz | Michael Cuntz | Fusion algebras with negative structure constants | 24 pages | null | null | null | math.RA | null | We introduce fusion algebras with not necessarily positive structure
constants and without identity element. We prove that they are semisimple when
tensored with $\mathbb{C}$ and that their characters satisfy orthogonality
relations. Then we define the proper notion of subrings and factor rings for
such algebras. For certain algebras $R$ we prove the existence of a ring $R'$
with nonnegative structure constants such that $R$ is a factor ring of $R'$. We
give some examples of interesting factor rings of the representation ring of
the quantum double of a finite group. Then, we investigate the algebras
associated to Hadamard matrices. For an $n\times n$-matrix the corresponding
algebra is a factor ring of a subalgebra of
$\mathbb{Z}[{(\mathbb{Z}/2\mathbb{Z})}^{n-2}]$.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 16:39:58 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Cuntz",
"Michael",
""
]
] |
0704.2385 | H. Rudolf Fiebig | M. S. Cook and H. R. Fiebig | Lattice QCD study of a five-quark hadronic molecule | 11 pages, 15 figures, 4 tables | Phys.Rev.D76:054507,2007 | 10.1103/PhysRevD.76.054507 | null | hep-lat | null | We compute the ground-state energies of a heavy-light K-Lambda like system as
a function of the relative distance r of the hadrons. The heavy quarks, one in
each hadron, are treated as static. Then, the energies give rise to an
adiabatic potential Va(r) which we use to study the structure of the five-quark
system. The simulation is based on an anisotropic and asymmetric lattice with
Wilson fermions. Energies are extracted from spectral density functions
obtained with the maximum entropy method. Our results are meant to give
qualitative insight: Using the resulting adiabatic potential in a Schroedinger
equation produces bound state wave functions which indicate that the ground
state of the five-quark system resembles a hadronic molecule, whereas the first
excited state, having a very small rms radius, is probably better described as
a five-quark cluster, or a pentaquark. We hypothesize that an all light-quark
pentaquark may not exist, but in the heavy-quark sector it might, albeit only
as an excited state.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 16:41:17 GMT"
},
{
"version": "v2",
"created": "Thu, 26 Jul 2007 23:41:22 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Cook",
"M. S.",
""
],
[
"Fiebig",
"H. R.",
""
]
] |
0704.2386 | Pilar Albert | Pilar Albert, Elvira Mayordomo, and Philippe Moser | Bounded Pushdown dimension vs Lempel Ziv information density | null | null | null | null | cs.CC cs.IT math.IT | null | In this paper we introduce a variant of pushdown dimension called bounded
pushdown (BPD) dimension, that measures the density of information contained in
a sequence, relative to a BPD automata, i.e. a finite state machine equipped
with an extra infinite memory stack, with the additional requirement that every
input symbol only allows a bounded number of stack movements. BPD automata are
a natural real-time restriction of pushdown automata. We show that BPD
dimension is a robust notion by giving an equivalent characterization of BPD
dimension in terms of BPD compressors. We then study the relationships between
BPD compression, and the standard Lempel-Ziv (LZ) compression algorithm, and
show that in contrast to the finite-state compressor case, LZ is not universal
for bounded pushdown compressors in a strong sense: we construct a sequence
that LZ fails to compress signicantly, but that is compressed by at least a
factor 2 by a BPD compressor. As a corollary we obtain a strong separation
between finite-state and BPD dimension.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 16:49:48 GMT"
}
] | 2007-07-13T00:00:00 | [
[
"Albert",
"Pilar",
""
],
[
"Mayordomo",
"Elvira",
""
],
[
"Moser",
"Philippe",
""
]
] |
0704.2387 | Joseph Anderson | J.P. Anderson, P.A. James, M. Salaris and S.M. Percival | Constraints on supernova progenitors from spatial correlations with
H-alpha emission | To appear in conference proceedings: "Supernova 1987A: 20 Years After
-- Supernovae & Gamma-Ray Bursters", held in Aspen, February 2007 | AIP Conf.Proc.937:220-224,2007 | 10.1063/1.2803566 | null | astro-ph | null | We have attempted to constrain the progenitors of all supernova types,
through correlations of the positions of historical supernovae with recent star
formation, as traced by H-alpha emission. Through pixel statistics we have
found that a large fraction of the SNII population do not show any association
with current star formation, which we put down to a 'runaway' fraction of these
progenitors. The SNIb/c population accurately traces the H-alpha emission, with
some suggestion that the SNIc progenitors show a higher degree of correlation
than the SNIb, suggesting higher mass progenitors for the former. Overall the
SNIa population only show a weak correlation to the positions of HII regions,
but as many as a half may be associated with a young stellar population.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 16:52:43 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"Anderson",
"J. P.",
""
],
[
"James",
"P. A.",
""
],
[
"Salaris",
"M.",
""
],
[
"Percival",
"S. M.",
""
]
] |
0704.2388 | Stephane Merigon | Stephane Merigon (IECN) | L'indice de Maslov dans les $JB^*$-triples | null | null | null | null | math.GM | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We construct a homotopy invariant index for pathes in the set of invertible
tripotents in a JB*-triple that satisfy a Fredholm type condition with respect
to a fixed invertible tripotent. That index generalizes the Maslov index in the
Fredholm-Lagrangian of a symplectic Hilbert space.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 15:04:43 GMT"
},
{
"version": "v2",
"created": "Tue, 16 Jun 2009 13:39:29 GMT"
}
] | 2009-09-29T00:00:00 | [
[
"Merigon",
"Stephane",
"",
"IECN"
]
] |
0704.2389 | Georgios Papathanasiou | Georgios Papathanasiou and Marcus Spradlin | Semiclassical Quantization of the Giant Magnon | 20 pages, JHEP3 style; v2: minor typos fixed and references added | JHEP 0706:032,2007 | 10.1088/1126-6708/2007/06/032 | BROWN-HET-1479 | hep-th | null | Solitons in field theory provide a window into regimes not directly
accessible by the fundamental perturbative degrees of freedom. Motivated by
interest in the worldsheet S-matrix of string theory in AdS_5 x S^5 in the
limit of infinite worldsheet volume we consider the semiclassical quantization
of a particular soliton of this theory: the Hofman-Maldacena `giant magnon'
spinning string. We obtain explicit formulas for the complete spectrum of
bosonic and fermionic fluctuations around the giant magnon. As an application
of these results we confirm that the one-loop correction to the classical
energy vanishes as expected.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 18:35:23 GMT"
},
{
"version": "v2",
"created": "Sat, 9 Jun 2007 23:40:15 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Papathanasiou",
"Georgios",
""
],
[
"Spradlin",
"Marcus",
""
]
] |
0704.2390 | Lidia Oskinova | L. M. Oskinova, W.-R. Hamann, and A. Feldmeier | Neglecting the porosity of hot-star winds can lead to underestimating
mass-loss rates | A&A (in press), see full abstract in the text | null | 10.1051/0004-6361:20066377 | null | astro-ph | null | Context: The mass-loss rate is a key parameter of massive stars. Adequate
stellar atmosphere models are required for spectral analyses and mass-loss
determinations. Present models can only account for the inhomogeneity of
stellar winds in the approximation of small-scale structures that are optically
thin. This treatment of ``microclumping'' has led to reducing empirical
mass-loss rates by factors of two and more. Aims: Stellar wind clumps can be
optically thick in spectral lines. We investigate how this ``macroclumping''
impacts on empirical mass-loss rates. Methods: The Potsdam Wolf-Rayet (PoWR)
model atmosphere code is generalized in the ``formal integral'' to account for
clumps that are not necessarily optically thin. Results: Optically thick clumps
reduce the effective opacity. This has a pronounced effect on the emergent
spectrum. Our modeling for the O-type supergiant zeta Puppis reveals that the
optically thin H-alpha line is not affected by wind porosity, but that the PV
resonance doublet becomes significantly weaker when macroclumping is taken into
account. The reported discrepancies between resonance-line and
recombination-line diagnostics can be resolved entirely with the macroclumping
modeling without downward revision of the mass-loss rate. Conclusions:
Mass-loss rates inferred from optically thin emission, such as the H-alpha line
in O stars, are not influenced by macroclumping. The strength of optically
thick lines, however, is reduced because of the porosity effects. Therefore,
neglecting the porosity in stellar wind modeling can lead to underestimating
empirical mass-loss rates.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 17:13:22 GMT"
},
{
"version": "v2",
"created": "Tue, 20 Nov 2007 12:59:39 GMT"
}
] | 2007-11-20T00:00:00 | [
[
"Oskinova",
"L. M.",
""
],
[
"Hamann",
"W. -R.",
""
],
[
"Feldmeier",
"A.",
""
]
] |
0704.2391 | Yusuke Sasano | Yusuke Sasano | Ordinary differential systems in dimension three with affine Weyl group
symmetry of types $D_4^{(1)},B_3^{(1)},G_2^{(1)},D_3^{(2)}$ and $A_2^{(2)}$ | 14 pages, 1 figure | null | null | null | math.AG | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We present a four-parameter family of ordinary differential systems in
dimension three with affine Weyl group symmetry of type $D_4^{(1)}$. By
obtaining its first integral, we can reduce this system to the second-order
non-linear ordinary differential equations of Painlev\'e type. We also study
this system restricted its parameters. Each system can be obtained by
connecting some invariant divisors in the system of type $D_4^{(1)}$. Each
system admits affine Weyl group symmetry of types
$B_3^{(1)},G_2^{(1)},D_3^{(2)}$ and $A_2^{(2)}$, respectively. These
symmetries, holomorphy conditions and invariant divisors are new.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 17:16:04 GMT"
},
{
"version": "v2",
"created": "Mon, 14 Dec 2009 13:18:54 GMT"
}
] | 2009-12-14T00:00:00 | [
[
"Sasano",
"Yusuke",
""
]
] |
0704.2392 | Tamas Unger | Alexander Ries, Tamas Unger, Dietrich E. Wolf | Shear zones in granular media: 3D Contact Dynamics simulation | 9 pages | Phys. Rev. E 76, 051301 (2007) | 10.1103/PhysRevE.76.051301 | null | cond-mat.soft cond-mat.stat-mech | null | Shear zone formation is investigated in slow 3D shear flows. We simulate the
linear version of the split-bottom shear cell. It is shown that the same type
of wide shear zones is achieved in the presence as well as in the absence of
gravity. We investigate the relaxation of the material towards a stationary
flow and analyze the stress and the velocity fields. We provide the functional
form of the widening of the shear zone inside the bulk. We discuss the growth
of the region where the material is in critical state. It is found that the
growth of the critical zone is responsible for the initial transient of the
shear zone.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 17:33:38 GMT"
},
{
"version": "v2",
"created": "Wed, 25 Apr 2007 18:26:17 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Ries",
"Alexander",
""
],
[
"Unger",
"Tamas",
""
],
[
"Wolf",
"Dietrich E.",
""
]
] |
0704.2393 | Yusuke Sasano | Yusuke Sasano | Symmetry in the Painlev\'e systems and their extensions to
four-dimensional systems | 32 pages, 16 figures | Funkcialaj Ekvacioj, 51 (2008) 351-369 | null | null | math.AG | null | We give a new approach to the symmetries of the Painlev\'e equations
$P_{V},P_{IV},P_{III}$ and $P_{II}$, respectively. Moreover, we make natural
extensions to fourth-order analogues for each of the Painlev\'e equations
$P_{V}$ and $P_{III}$, respectively, which are natural in the sense that they
preserve the symmetries.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 17:35:38 GMT"
}
] | 2010-11-04T00:00:00 | [
[
"Sasano",
"Yusuke",
""
]
] |
0704.2394 | B. Lee Roberts | B. Lee Roberts | Muon Physics: A Pillar of the Standard Model | 8 pages, 9 figures. Invited paper for the Journal of Physical Society
in Japan (JPSJ), Special Topics Issue "Frontiers of Elementary Particle
Physics, The Standard Model and beyond" | J.Phys.Soc.Jap.76:111009,2007 | 10.1143/JPSJ.76.111009 | null | hep-ex | null | Since its discovery in the 1930s, the muon has played an important role in
our quest to understand the sub-atomic theory of matter. The muon was the first
second-generation standard-model particle to be discovered, and its decay has
provided information on the (Vector -Axial Vector) structure of the weak
interaction, the strength of the weak interaction, G_F, and the conservation of
lepton number (flavor) in muon decay. The muon's anomalous magnetic moment has
played an important role in restricting theories of physics beyond the standard
standard model, where at present there is a 3.4 standard-deviation difference
between the experiment and standard-model theory. Its capture on the atomic
nucleus has provided valuable information on the modification of the weak
current by the strong interaction which is complementary to that obtained from
nuclear beta decay.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 17:41:21 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Roberts",
"B. Lee",
""
]
] |
0704.2395 | Maria Skopina | M. Skopina | Multivariate Wavelet Frames | LaTex file, 28 pages | null | null | null | math.CA | null | We proved that for any matrix dilation and for any positive integer $n$,
there exists a compactly supported tight wavelet frame with approximation order
$n$. Explicit methods for construction of dual and tight wavelet frames with a
given number of vanishing moments are suggested.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 17:44:27 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Skopina",
"M.",
""
]
] |
0704.2396 | Alexandre C. Tort | F. C. Santos, V. Soares, A. C. Tort | An English translation o Bertrand's theorem | This is English version of a beautiful theorem due to Joseph
Bertrand; simple latex file, no figures, six pages | Latin American Journal of Physics Education vol. 5 #4 694-696
(2011) | null | null | physics.class-ph physics.ed-ph | null | A beautiful theorem due to J. L. F. Bertrand concerning the laws of
attraction that admit bounded closed orbits for arbitrarily chosen initial
conditions is translated from French into English.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 18:10:35 GMT"
}
] | 2013-04-18T00:00:00 | [
[
"Santos",
"F. C.",
""
],
[
"Soares",
"V.",
""
],
[
"Tort",
"A. C.",
""
]
] |
0704.2397 | Jose Manuel Velhinho | J. M. Velhinho | The Quantum Configuration Space of Loop Quantum Cosmology | 14 pages. Minor changes, typos corrected, 1 reference added. To
appear in Class. Quantum Grav | Class.Quant.Grav.24:3745-3758,2007 | 10.1088/0264-9381/24/14/013 | null | gr-qc | null | The article gives an account of several aspects of the space known as the
Bohr compactification of the line, featuring as the quantum configuration space
in loop quantum cosmology, as well as of the corresponding configuration space
realization of the so-called polymer representation. Analogies with loop
quantum gravity are explored, providing an introduction to (part of) the
mathematical structure of loop quantum gravity, in a technically simpler
context.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 18:17:41 GMT"
},
{
"version": "v2",
"created": "Mon, 2 Jul 2007 17:27:53 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Velhinho",
"J. M.",
""
]
] |
0704.2398 | David B. Cline | D.B. Cline, C. Matthey, S. Otwinowski, B. Czerny, A. Janiuk | The Search for Primordial Black Holes Using Very Short Gamma Ray Bursts | 5 pages, 3 figures, talk given at the "Outstanding Questions for the
Standard Cosmological Model" meeting, Imperial College, UK, March 2007 | null | null | null | astro-ph | null | We show the locations of the SWIFT short hard bursts (SHB) with afterglows on
the galactic map and compare with the VSB BATSE events. As we have pointed out
before, there is an excess of events in the galactic map of BATSE VSB events.
We not that none of VSB SWIFT era events fall into this cluster. More SWIFT
events are needed to check this claim. We also report a new study with KONUS
data of the VSB sample with an average energy above 90 keV showing a clear
excess of events below 100 ms duration (T90) that have large mean energy
protons. We suggest that VSB themselves consist of two subclasses: a fraction
of events have peculiar distribution properties and have no detectable
counterparts, as might be expected for exotic sources such as primordial black
holes. We show how GLAST could add key new information to the study of VSB
bursts and could help test the black hole concept.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 18:24:17 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Cline",
"D. B.",
""
],
[
"Matthey",
"C.",
""
],
[
"Otwinowski",
"S.",
""
],
[
"Czerny",
"B.",
""
],
[
"Janiuk",
"A.",
""
]
] |
0704.2399 | Oleksii Smyrnov | Vadym M. Adamyan, Oleksii A. Smyrnov | Large radius exciton in single-walled carbon nanotubes | 14 pages, 1 figure, 5 tables | Journal of Physics A: Mathematical and Theoretical 40, 10519 (
2007) | 10.1088/1751-8113/40/34/009 | null | cond-mat.other | null | The spectrum of large radius exciton in an individual semiconducting
single-walled carbon nanotube (SWCNT) is described within the framework of
elementary potential model, in which exciton is modeled as bound state of two
oppositely charged quasi-particles confined on the tube surface. Due to the
parity of the interaction potential the exciton states split into the odd and
even series. It is shown that for the bare and screened Coulomb electron-hole
(e-h) potentials the binding energy of even excitons in the ground state well
exceeds the energy gap. The factors preventing the collapse of single-electron
states in isolated semiconducting SWCNTs are discussed.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 18:30:50 GMT"
},
{
"version": "v2",
"created": "Sat, 30 Jun 2007 14:38:42 GMT"
}
] | 2010-11-18T00:00:00 | [
[
"Adamyan",
"Vadym M.",
""
],
[
"Smyrnov",
"Oleksii A.",
""
]
] |
0704.2400 | Tord Riemann | S. Actis (DESY), M. Czakon (U. Wuerzburg), J. Gluza (U. Katowice), T.
Riemann (DESY) | Two-Loop Fermionic Corrections to Massive Bhabha Scattering | 22 pages, 5 tables, 5 figures, eq. 4.9 corrected | Nucl.Phys.B786:26-51,2007 | 10.1016/j.nuclphysb.2007.06.023 | DESY 07-053, SFB/CPP-07-15, HEPTOOLS 07-010 | hep-ph | null | We evaluate the two-loop corrections to Bhabha scattering from fermion loops
in the context of pure Quantum Electrodynamics. The differential cross section
is expressed by a small number of Master Integrals with exact dependence on the
fermion masses me, mf and the Mandelstam invariants s,t,u. We determine the
limit of fixed scattering angle and high energy, assuming the hierarchy of
scales me^2 << mf^2 << s,t,u. The numerical result is combined with the
available non-fermionic contributions. As a by-product, we provide an
independent check of the known electron-loop contributions.
| [
{
"version": "v1",
"created": "Wed, 18 Apr 2007 18:59:13 GMT"
},
{
"version": "v2",
"created": "Fri, 27 Apr 2007 19:55:19 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Actis",
"S.",
"",
"DESY"
],
[
"Czakon",
"M.",
"",
"U. Wuerzburg"
],
[
"Gluza",
"J.",
"",
"U. Katowice"
],
[
"Riemann",
"T.",
"",
"DESY"
]
] |
Subsets and Splits