August 2003 arXiv papers — page 23

A. D. Martin, R. G. Roberts, W. J. Stirling, R. S. Thorne

We study the uncertainties in parton distributions, determined in global fits to deep inelastic and related hard scattering data, due to so-called theoretical errors. Amongst these, we include potential errors due to the change of perturbative order (NLO to NNLO), ln(1/x) and ln(1-x) effects, absorptive corrections and higher-twist contributions. We investig

Kevin Lee Haglin

Thermal photon emission rates from hot hadronic matter are studied to order $e^{2}g^{4}$, where $g$ indicates a strong-interaction coupling constant. Radiative decay of mesons, Compton and annihilation processes for hadrons, and bremsstrahlung reactions are all considered. Compared to the standard rates from the literature, one finds two orders of magnitude

A. D. Dolgov, F. L. Villante

Nucleosynthesis restrictions on mixing of active neutrinos with possible sterile ones are obtained with the account of experimentally determined mixing between all active neutrinos. The earlier derived bounds, valid in the absence of active-active mixing, are reanalyzed and significant difference is found in the resonance case. The results are obtained both

Christopher Smith

In order to fulfill Low's theorem requirements, a new lowest order basis for bound state decay computations is proposed, in which the binding energy is treated non-perturbatively. The properties of the method are sketched by reviewing standard positronium decay processes. Then, it is shown how applying the method to quarkonia sheds new light on some long

Jihn E. Kim

The axion solution of the strong CP problem is reviewed together with the other strong CP solutions. We also point out the quintessential axion(quintaxion) whose potential can be extremely flat due to the tiny ratio of the hidden sector quark mass and the intermediate hidden sector scale. The quintaxion candidates are supposed to be the string theory axions,

Tomohiro Inagaki

It is investigated that a dynamical mechanism to generate a low mass fermion in Randall-Sundrum (RS) background. We consider a five-dimensional four- fermion interaction model with two kinds of bulk fermion fields and take all the mass scale in the five-dimensional spacetime at the Planck scale. Evaluating the effective potential of the induced four-dimensio

John Ellis, Keith A. Olive, Yudi Santoso, Vassilis C. Spanos

The requirement that the MSSM remain an acceptable effective field theory up to energies beyond the weak scale constrains the sparticle spectrum, and hence the permissible ranges of cold dark matter neutralino-proton cross sections. Specifically, squarks are generally much heavier than sleptons if no tachyons are to appear before the GUT scale ~10^16 GeV, or

T. Babutsidze, T. Kopaleishvili, D. Kurashvili

The two-body Dirac equations for the bound q bar q systems are obtained from the different (five) versions of the 3D-equations derived from Bethe-Salpeter equation with the instantaneous kernel in the momentum space using the additional approximations. There are formulated the normalization conditions for the wave functions satisfying the obtained two-body D

The BABAR Collaboration, B. Aubert

We present model-independent measurements of the branching fractions ${\cal B}(B^0\to D_s^{*+} D^{*-})$ and ${\cal B}(D_s^+ \to ϕπ^+)$ based on 19.3 $\textup{fb}^{-1}$ of data collected by the $BABAR$ detector at the PEP-II $e^+e^-$ $B$ Factory. Neutral $B$-meson decays to the $D_s^{*+}D^{*-}$ final state are selected with a partial reconstruction of the $D_

The BABAR Collaboration, B. Aubert

We present a measurement of the branching fraction for the flavor-changing neutral current process B --> Xs l+ l- based on a sample of 88.9 \times 10^6 Upsilon(4S) --> BBbar events recorded with the BaBar detector at the PEP-II e+e- storage ring. The final state is reconstructed from pairs of electrons or muons and a hadronic system consisting of one K+/- or

The BABAR Collaboration, B. Aubert

We present preliminary measurements of branching fractions and charge asymmetries for the B meson decays B -> eta(')K*, B -> eta(')rho, and B+ -> eta' pi+. The data were recorded with the BaBar detector at PEP-II and correspond to 89 x 10^6 B B-bar pairs produced in e+e- annihilation through the Upsilon(4S) resonance. We find the branching fracti

A. M. Eisner

Recent BABAR and Belle results on rare B decays involving photons or lepton pairs are reviewed. New preliminary limits from both experiments for B-->rho gamma and B-->omega gamma, and from BABAR for B --> K nu nu and B --> tau nu are presented. Also summarized from the past year are Belle measurements of B-->Xs l+l- and B0-->K2(1430) gamma, preliminary BABAR

G. J. Milburn

Quantum decoherence can arise due to classical fluctuations in the parameters which define the dynamics of the system. In this case decoherence, and complementary noise, is manifest when data from repeated measurement trials are combined. Recently a number of authors have suggested that fluctuations in the space-time metric arising from quantum gravity effec

Metin Gurses, Ozgur Sarioglu

We extend the previously found accelerated Kerr-Schild metrics for Einstein-Maxwell-null dust and Einstein-Born-Infeld-null dust equations to the cases including the cosmological constant. This way we obtain the generalization of the charged de Sitter metrics in static space-times. We also give a generalization of the zero acceleration limit of our previous

G. Allemandi, M. Francaviglia, M. Raiteri

Starting from the SO(2,2n) Chern-Simons form in (2n+1) dimensions we calculate the variation of conserved quantities in Lovelock gravity and Lovelock-Maxwell gravity through the covariant formalism developed in gr-qc/0305047. Despite the technical complexity of the Lovelock Lagrangian we obtain a remarkably simple expression for the variation of the charges

Abdussattar

Considering the physical 3-space t = constant of the spacetime metrics as spheroidal and pseudo spheroidal, cosmological models which are generalizations of Robertson-Walker models are obtained. Specific forms of these general models as solutions of Einstein's field equations are also discussed in the radiation- and the matter-dominated eras of the unive

Rolando Gaitan

A covariant scheme for material coupling with $GL(N,R)$ gauge formulation of gravity is studied. We revisit a known idea of a Yang-Mills type construction, where quadratical power of cosmological constant have to be considered in consistence with vacuum Einstein's gravity. Then, matter coupling with gravity is introduced and some constraints on fields an

Akshar Bharati, Dipti M Sharma, Vineet Chaitanya, Amba P Kulkarni

The paper reports on efforts taken to create lexical resources pertaining to Indian languages, using the collaborative model. The lexical resources being developed are: (1) Transfer lexicon and grammar from English to several Indian languages. (2) Dependencey tree bank of annotated corpora for several Indian languages. The dependency trees are based on the P

Akshar Bharati, Vineet Chaitanya, Amba P. Kulkarni, Rajeev Sangal

The anusaaraka system (a kind of machine translation system) makes text in one Indian language accessible through another Indian language. The machine presents an image of the source text in a language close to the target language. In the image, some constructions of the source language (which do not have equivalents in the target language) spill over to the

Akshar Bharati, Vineet Chaitanya, Amba P. Kulkarni, Rajeev Sangal

The anusaaraka system makes text in one Indian language accessible in another Indian language. In the anusaaraka approach, the load is so divided between man and computer that the language load is taken by the machine, and the interpretation of the text is left to the man. The machine presents an image of the source text in a language close to the target lan

Akshar Bharati, Vineet Chaitanya, Rajeev Sangal

The world is passing through a major revolution called the information revolution, in which information and knowledge is becoming available to people in unprecedented amounts wherever and whenever they need it. Those societies which fail to take advantage of the new technology will be left behind, just like in the industrial revolution. The information revol

Akshar Bharati, Rajeev Sangal

The world is passing through a major revolution called the information revolution, in which information and knowledge is becoming available to people in unprecedented amounts wherever and whenever they need it. Those societies which fail to take advantage of the new technology will be left behind, just like in the industrial revolution. The information revol

Shinji Yamane, Jiahong Wang, Hironobu Suzuki, Norihisa Segawa

OpenPGP, an IETF Proposed Standard based on PGP application, has its own Public Key Infrastructure (PKI) architecture which is different from the one based on X.509, another standard from ITU. This paper describes the OpenPGP PKI; the historical perspective as well as its current use. The current OpenPGP PKI issues include the capability of a PGP keyserver a

R. S. Gonnelli, D. Daghero, A. Calzolari, G. A. Ummarino

We present the results of directional point-contact measurements in MgB_2 single crystals, in magnetic fields up to 9 T parallel to the c axis. By fitting the conductance curves of our point contacts -- showing clear Andreev-reflection features -- with a generalized Blonder-Tinkham-Klapwijk model, we were able to extract the values of the two gaps Delta_sigm

R. Rapaport, Gang Chen, D. Snoke, Steve H. Simon

About a year ago, two independent experiments [1,2], imaging indirect exciton luminescence from doped double quantum wells under applied bias and optical excitation, reported a very intriguing observation: under certain experimental conditions, the exciton luminescence exhibits a ring pattern with a dark region in between the center excitation spot and the l

K. -K. Voo, W. C. Wu, H. -Y. Chen, C. -Y. Mou

Based on a Fermi liquid picture, the temperature effect on the impurity-induced spatial modulation of local density of states (LDOS) is investigated for the d-wave superconductor Bi$_2$Sr$_2$CaCu$_2$O$_8$, in the context of scanning tunneling microscopy (STM). It is found that stripe-like structure exists even in the normal state due to a local-nesting mecha

Kurt Binder, Jurgen Horbach, Walter Kob, Wolfgang Paul

A tutorial introduction to the technique of Molecular Dynamics (MD) is given, and some characteristic examples of applications are described. The purpose and scope of these simulations and the relation to other simulation methods is discussed, and the basic MD algorithms are described. The sampling of intensive variables (temperature T, pressure p) in runs c

Andrea Montanari, Giorgio Parisi, Federico Ricci-Tersenghi

We reconsider the one-step replica-symmetry-breaking (1RSB) solutions of two random combinatorial problems: k-XORSAT and k-SAT. We present a general method for establishing the stability of these solutions with respect to further steps of replica-symmetry breaking. Our approach extends the ideas of [A.Montanari and F. Ricci-Tersenghi, Eur.Phys.J. B 33, 339 (

Ph. Mavropoulos, K. Sato, R. Zeller, P. H. Dederichs

The spin-orbit interaction can cause a nonvanishing density of states (DOS) within the minority-spin band gap of half-metals around the Fermi level. We examine the magnitude of the effect in Heusler alloys, zinc-blende half metals and diluted magnetic semiconductors, using first-principles calculations. We find that the ratio of spin-down to spin-up DOS at t

S. Denisov, A. Filippov, J. Klafter, M. Urbakh

We investigate a one-dimenisonal Hamiltonian system that describes a system of particles interacting through short-range repulsive potentials. Depending on the particle mean energy, $ε$, the system demonstrates a spectrum of kinetic regimes, characterized by their transport properties ranging from ballistic motion to localized oscillations through anomalous

T. Keyes, J. Chowdhary

The inherent structures ({\it IS}) are the local minima of the potential energy surface or landscape, $U({\bf r})$, of an {\it N} atom system. Stillinger has given an exact {\it IS} formulation of thermodynamics. Here the implications for the equation of state are investigated. It is shown that the van der Waals ({\it vdW}) equation, with density-dependent $

O. Wunnicke, Ph. Mavropoulos, R. Zeller, P. H. Dederichs

We present first-principles calculations of ballistic spin injection in Fe/GaAs and Fe/ZnSe junctions with orientation (001), (111), and (110). We find that the symmetry mismatch of the Fe minority-spin states with the semiconductor conduction states can lead to extremely high spin polarization of the current through the (001) interface for hot and thermal i

G. B. Lesovik

We present the most complete scattering theory for noise in noninteracting case. The exact formula for spectral density of current fluctuations at finite frequency is presented in terms of scattering matrix for a coherent quantum conductor. We show that the shot noise at finite frequency in an ideally conducting contact is finite and the spectral density of

Osvaldo F. Schilling

In this paper we discuss the phenomenon of resonance that we predict will occur when a superconducting coil is submitted simultaneously to a magnetic field and to an external force. When both the force and the magnetic field are constant in time the coil should oscillate mechanically around an equilibrium position like an ideal harmonic oscillator, and shoul

L. Cacciapuoti, D. Hellweg, M. Kottke, T. Schulte

The coherence properties of phase fluctuating Bose-Einstein condensates are studied both theoretically and experimentally. We derive a general expression for the N-particle correlation function of a condensed Bose gas in a highly elongated trapping potential. The second order correlation function is analyzed in detail and an interferometric method to directl

Naoum Karchev

It is assumed that U atoms in $UGe_2$ have a number of $f$ electrons appropriate to give them each a spin $s=1$ as well as one extra itinerant electron which may equally well be on one or other U atom. The dynamical degrees of freedom are spin-s operators of localized spins and spin-1/2 fermi operators of itinerant electrons. Applying hydrostatic pressure ch

A. V. Galaktionov, D. S. Golubev, A. D. Zaikin

We formulate a general approach which describes statistics of current fluctuations in mesoscopic coherent conductors at arbitrary frequencies and in the presence of interactions. Applying this approach to the non-interacting case, we analyze frequency dispersion of the third cumulant of the current operator ${\cal S}_3$ at frequencies well below both the inv

Marco Zoli

The path integral formalism is applied to derive the full partition function of a generalized Su-Schrieffer-Heeger Hamiltonian describing a particle motion in a bath of oscillators. The electronic correlations are computed versus temperature for some choices of oscillators energies. We study the perturbing effect of a time averaged particle path on the phono

Marco Zoli

The electron motion along a chain is described by a continuum version of the Su-Schrieffer-Heeger Hamiltonian in which phonon fields and electronic coordinates are mapped onto the time scale. The path integral formalism allows us to derive the non local source action for the particle interacting with the oscillators bath. The method can be applied for any va

T. Masui, M. Limonov, H. Uchiyama, S. Lee

Raman scattering in the heavily overdoped (Y,Ca)Ba_2Cu_3O_{7-d} (T_c = 65 K) and Bi_2Sr_2CaCu_2O_{8+d} (T_c = 55 K) crystals has been investigated. For the both crystals, the electronic pair-breaking peaks in the A_{1g} and B_{1g} polarizations were largely shifted to the low energies close to a half of 2Delta_0, Delta_0 being the maximum gap. It strongly su

Gabor Oszlanyi, Andras Suto

In this paper we present an extremely simple structure solution method termed charge flipping. It works ab initio on high resolution x-ray diffraction data in the manner of Fourier recycling. The real space modification simply changes the sign of charge density below a threshold, while in reciprocal space the modification is the Fobs map without any weightin

K. L. Ng, S. P. Li

A new family of compound Poisson distribution functions from statistical linguistic is used to study the n-tuples and nucleotide composition features of DNA sequences. The relative frequency distribution of the 6-tuples and 7- tuples occurrence studies suggest that most of the DNA sequences follow the general shape of the compound Poisson distribution. It is

V. I. Yukalov

General conditions for the occurrence of mesoscopic phase fluctuations in condensed matter are considered. The description of different thermodynamic phases, which coexist as a mixture of mesoscopically separated regions, is based on the {\it theory of heterophase fluctuations}. The spaces of states, typical of the related phases, are characterized by {\it w

A. G. Marinopoulos, Ludger Wirtz, Andrea Marini, Valerio Olevano

We present results for the optical absorption spectra of small-diameter single-wall carbon and boron nitride nanotubes obtained by {\it ab initio} calculations in the framework of time-dependent density functional theory. We compare the results with those obtained for the corresponding layered structures, i.e. the graphene and hexagonal BN sheets. In particu

Yair Srebro, Dov Levine

We investigate the role of friction in compaction and segregation of granular materials by combining Edwards' thermodynamic hypothesis with a simple mechanical model and mean-field based geometrical calculations. Systems of single species with large friction coefficients are found to compact less. Binary mixtures of grains differing in frictional propert

L. M. Kettle, H. S. Goan, Sean C. Smith, C. J. Wellard

In this paper we examine the effects of varying several experimental parameters in the Kane quantum computer architecture: A-gate voltage, the qubit depth below the silicon oxide barrier, and the back gate depth to explore how these variables affect the electron density of the donor electron. In particular, we calculate the resonance frequency of the donor n

Benny Davidovitch, Deniz Ertas, Thomas C. Halsey

We study the shape and growth rate of necks between sintered spheres with dissolution-precipitation dynamics in the reaction-limited regime. We determine the critical shape that separates those initial neck shapes that can sinter from those that necessarily dissolve, as well as the asymptotic evolving shape of sinters far from the critical shape. We compare

Raul Perez-Enriquez

A new parameter named PESATc (Parametro Estructural de los Superconductores de Alta Temperatura critica) is presented and used to discuss an aproach to the 'Stripe Phases' in (La,Ca)MnO3 superconductors. The PESATc parameter is based on the superposition of an Octahedrical Moebius Strip over the CuO planes and apical oxygen O(4). The linear correlati

Chris H. Wiggins, Alberto Montesi, Matteo Pasquali

Traditional models of wormlike chains in shear flows at finite temperature approximate the equation of motion via finite difference discretization (bead and rod models). We introduce here a new method based on a spectral representation in terms of the natural eigenfunctions. This formulation separates tumbling and bending dynamics, clearly showing their inte

Ji-Lin Zhou, Yi-Sui Sun

With the help of the Laplace-Lagrange solution of the secular perturbation theory in a double-planet system, we study the occurrence and the stability of apsidal secular resonance between the two planets. The explicit criteria to predict whether two planets are in apsidal resonance is derived. The pobability of two planets falling in apsidal resonance is giv

Simon P Goodwin, D. Ward-Thompson, A. P. Whitworth

We evaluate the intrinsic three dimensional shapes of molecular cores, by analysing their projected shapes. We use the recent catalogue of molecular line observations of Jijina et al. and model the data by the method originally devised for elliptical galaxies. Our analysis broadly supports the conclusion of Jones et al. that molecular cores are better repres

K. J. Inskip, P. N. Best, M. S. Longair, S. Rawlings

The results of Hubble Space Telescope and UKIRT imaging observations are presented for a sample of 11 6C radio galaxies with redshifts 0.85 < z < 1.5. The observations of the 6C sources reveal a variety of different features, similar to those observed around the higher luminosity of the aligned emission appears less extreme in the case of the 6C radio galaxi

Frank C. van den Bosch, Tom Abel, Lars Hernquist

We examine the effect of preheating of the intergalactic medium on galaxy formation using cosmological hydrodynamical simulations. By performing simulations both with and without a simple model for preheating, we analyse and compare the angular momentum distributions of the dark matter and the baryons. Preheating unbinds baryons from their dark matter haloes

Yi-Jehng Kuan, Chi-Hung Yan, Steven B. Charnley, Zbigniew Kisiel

We have searched three hot molecular cores for submillimeter emission from the nucleic acid building-block pyrimidine. We obtain upper limits to the total pyrimidine (beam-averaged) column densities towards Sgr B2(N), Orion KL and W51 e1/e2 of 1.7E+14 cm^{-2}, 2.4E+14 cm^{-2} and 3.4E+14 cm^{-2}, respectively. The associated upper limits to the pyrimidine fr

Suparna Roychowdhury, Biman B. Nath

We study the X-ray cluster gas density distribution in hydrostatic equilibrium using the universal temperature profile obtained from recent simulations involving only gravitational processes. If this temperature profile is an indicator of the influence of gravitational processes alone on the intracluster medium, then the comparison of various X-ray parameter

Y. Urata, S. Nishiura, T. Miyata, H. Mito

Observations were made of the optical afterglow of GRB020813 (Fox, Blake & Price, 2002) with the KISO observatory 1.05 m Schmidt telescope and the Bisei astronomical observatory 1.01 m telescope. Four-band ($B, V, R$, and $I$) photometric data points were obtained from 2002, August 13 10:52 to 16:46 UT, or 0.346$-$0.516 days after the burst. In order to inve

Edward W. Thommes, Jack J. Lissauer

The observed orbits of extrasolar planets suggest that many giant planets migrate a considerable distance towards their parent star as a result of interactions with the protoplanetary disk, and that some of these planets become trapped in eccentricity-exciting mean motion resonances with one another during this migration. Using three-dimensional numerical si

Daniel S. Hudson, Mark J. Henriksen

We report the first localization of diffuse, non-thermal, X-ray emission from a nearby galaxy cluster. Using Chandra data, we have isolated a diffuse non-thermal X-ray component with a photon index, Gamma_ X = 2.21 +0.14 -0.15 and a flux of 9.5 +1.1 -2.5 x 10^-5 photons cm^-2 s^-1 keV^-1 at 1 keV, that extends from ~1&#39;.5 to ~2&#39;.5 to the south of the

G. Vereshchagin

New type of nonsingular oscillating solutions for the Universe described by cosmological equations of gauge theories of gravity is presented. Advantages of these solutions with respect to existing nonsingular solutions within framework of general relativity and gauge gravity are discussed. It is shown in particular that these solutions have nonzero measure a

Michael Martin Nieto, Slava G. Turyshev

NASA has been considering a solar sail that would accelerate a craft to a high velocity (~ 14 AU/yr) by the time it reached 5 AU. Then the sail would be dropped and the craft would coast alone to deep space. We propose that the sail be retained longer. Then the density of the interplanetary medium could be determined by measuring the drag force on the huge s

Michael Martin Nieto, Slava G. Turyshev

Analysis of radio-metric tracking data from the Pioneer 10/11 spacecraft at distances between 20 - 70 astronomical units (AU) from the Sun has consistently indicated the presence of an anomalous, small, constant Doppler frequency drift. The drift can be interpreted as being due to a constant acceleration of a_P= (8.74 \pm 1.33) x 10^{-8} cm/s^2 directed towa

A. A. Aligia

We extend to charge and bond operators the transformation that maps the ionic Hubbard model at half filling onto an effective spin Hamiltonian. Using these operators we calculate the amplitude of the charge density wave in different dimensions. In one dimension, the charge-charge correlations at large distance d decay as 1/(d^3 ln^{3/2}d), in spite of the pr

P. Bicudo, G. M. Marques

We study the very recently discovered Theta+ (1540) at SPring-8, at ITEP and at CLAS-Thomas Jefferson Lab. We apply the same RGM techniques that already explained with success the repulsive hard core of nucleon-nucleon, kaon-nucleon exotic scattering, and the attractive hard core present in pion-nucleon and pion-pion non-exotic scattering. We find that the K

A. N. Sissakian, O. Yu. Shevchenko, V. N. Samoilov

The scalar field theory and the scalar electrodynamics quantized in the flat gap are considered. The dynamical effects arising due to the boundary presence with two types of boundary conditions (BC) satisfied by scalar fields are studied. It is shown that while the Neumann BC lead to the usual scalar field mass generation, the Dirichlet BC give rise to the d

Crystal Ball Collaboration, J. Olmsted, S. Prakhov, D. M. Manley

Precise new data for the reaction $K^- p \to π^0 Λ$ are presented in the c.m. energy range 1565 to 1600 MeV. Our analysis of these data sheds new light on claims for the $Σ(1580){3/2}^-$ resonance, which (if it exists with the specified quantum numbers) must be an exotic baryon because of its very low mass. Our results show no evidence for this state.

Maurice H. P. M. van Putten, Amir Levinson, Hyun Kyu Lee, Tania Regimbau

Gamma-ray bursts are believed to originate in core-collapse of massive stars. This produces an active nucleus containing a rapidly rotating Kerr black hole surrounded by a uniformly magnetized torus represented by two counter-oriented current rings. We quantify black hole spin-interactions with the torus and charged particles along open magnetic flux-tubes s

Klaus Behrndt, Mirjam Cvetic

We study N=1 supersymmetric four-dimensional solutions of massive Type IIA supergravity with intersecting D6-branes in the presence NS-NS three-form fluxes. We derive N=1 supersymmetry conditions for the D6-brane and flux configurations in an internal manifold $X_6$ and derive the intrinsic torsion (or SU(3)-structure) related to the fluxes. In the absence o

Vivek V. Shende, Igor L. Markov, Stephen S. Bullock

We give quantum circuits that simulate an arbitrary two-qubit unitary operator up to global phase. For several quantum gate libraries we prove that gate counts are optimal in worst and average cases. Our lower and upper bounds compare favorably to previously published results. Temporary storage is not used because it tends to be expensive in physical impleme

Michael Gutperle, Per Kraus

Recent work has shown that unstable D-branes in two dimensional string theory are represented by eigenvalues in a dual matrix model. We elaborate on this proposal by showing how to systematically include higher order effects in string perturbation theory. The full closed string state produced by a rolling open string tachyon corresponds to a sum of string am

Behnam Farid

Recent data from angle-resolved photoemission experiments published by Zhou et al. [Nature, Vol. 423, 398 (2003)] concerning a number of hole-doped copper-oxide-based high-temperature superconductors reveal that in the nodal directions of the underlying square Brillouin zones (i.e. the directions along which the d-wave superconducting gap is vanishing) the F

Heron Caldas

We study the behavior of the $π^0$ width as a function of temperature and density. We provide simple expressions for the neutral pion width in a hot and dense medium based on a renormalized version of the microscopic Nambu Jona Lasinio model. Then we consider the two cases where the pion mass is finite or vanishes at the critical temperature and discuss the

Juha Javanainen, Janne Ruostekoski

We study theoretically a Fermi-Dirac atomic gas in a one-dimensional optical lattice coupled to a coherent electromagnetic field with a topologically nontrivial soliton phase profile. We argue that the resulting fractional eigenvalues of the particle number operator can be detected via light scattering. This could be a truly quantum mechanical measurement of

Philippe Gaucher

We construct a cofibrantly generated model structure on the category of flows such that any flow is fibrant and such that two cofibrant flows are homotopy equivalent for this model structure if and only if they are S-homotopy equivalent. This result provides an interpretation of the notion of S-homotopy equivalence in the framework of model categories.

Paul B. Slater

Extensive numerical integration results lead us to conjecture that the silver mean, that is, s = \sqrt{2}-1 = .414214 plays a fundamental role in certain geometries (those given by monotone metrics) imposable on the 15-dimensional convex set of two-qubit systems. For example, we hypothesize that the volume of separable two-qubit states, as measured in terms

Jan Troost

By carefully analyzing the radial part of the wave-equation for a scalar field in AdS, we show that for a particular range of boundary conditions on the scalar field, the radial spectrum contains a bound state. Using the AdS/CFT correspondence, we interpret this peculiar phenomenon as being dual to an unstable double trace deformation of the boundary conform

Leonid Prigozhin, Vladimir Sokolovsky

Magnetic field fluctuations are inevitable in practical applications of superconductors and it is often necessary to estimate the AC losses these fluctuations induce. If the fluctuation wavelength is greater than the size of a superconductor, known estimates for an alternating uniform external magnetic field can be employed. Here we consider the opposite cas

N. Bartolo, S. Matarrese, A. Riotto

We study the evolution of cosmological perturbations on large scales, up to second order, for a perfect fluid with generic equation of state. Taking advantage of super-horizon conservation laws, it is possible to follow the evolution of the non-Gaussianity of perturbations through the different stages after inflation. We find that a large non-linearity is ge

Manoj Gopalakrishnan

We study the motion of a particle sliding under the action of an external field on a stochastically fluctuating one-dimensional Edwards-Wilkinson surface. Numerical simulations using the single-step model shows that the mean-square displacement of the sliding particle shows distinct dynamic scaling behavior, depending on whether the surface fluctuates faster

S. V. Vadawale, A. R. Rao, S. Naik, J. S. Yadav

We investigate the association between the radio ``plateau&#39;&#39; states and the large superluminal flares in GRS 1915+105 and propose a qualitative scenario to explain this association. We identify several candidate superluminal flare events from available monitoring data on this source and analyze the contemporaneous RXTE pointed observations. We detect

Golam Mortuza Hossain

We present a construction of the Hubble operator for the spatially flat isotropic loop quantum cosmology. This operator is a Dirac observable on a subspace of the space of physical solutions. This subspace gets selected dynamically, requiring that its action be invariant on the physical solution space. As a simple illustrative application of the expectation

D. J. Bedingham

Large-volume, high-temperature Bose-Einstein condensation is illustrated for a relativistic O(2)-invariant scalar field with fixed charge using the canonical ensemble. The standard, grand canonical results are reproduced for the infinite-volume limit. Finite-volume corrections are calculated in the canonical ensemble and the results are found to differ from

Matthias R. Schreiber, Jean-Marie Hameury, Jean-Pierre Lasota

Using the disc instability model and a simple but physically reasonable model for the X-ray, extreme UV, UV and optical emission of dwarf novae we investigate the time lags observed between the rise to outburst at different wavelengths. We find that for ``normal&#39;&#39;, i.e. fast-rise outbursts, there is good agreement between the model and observations p

P. Hersen

Aeolian sand dunes originate from wind flow and sand bed interactions. According to wind properties and sand availability, they can adopt different shapes, ranging from huge motion-less star dunes to small and mobile barchan dunes. The latter are crescentic and emerge under a unidirectional wind, with a low sand supply. Here, a 3d model for barchan based on

Thomas Voigt, Günter M. Ziegler

Let $P(d)$ be the probability that a random 0/1-matrix of size $d \times d$ is singular, and let $E(d)$ be the expected number of 0/1-vectors in the linear subspace spanned by d-1 random independent 0/1-vectors. (So $E(d)$ is the expected number of cube vertices on a random affine hyperplane spanned by vertices of the cube.) We prove that bounds on $P(d)$ ar

Hiroya Nakao

A system of globally coupled phase oscillators subject to an external input is considered as a simple model of neural circuits coding external stimulus. The information coding efficiency of the system in its asynchronous state is quantified using Fisher information. The effect of coupling and noise on the information coding efficiency in the stationary state

S. Y. Choi

In the CP-invariant supersymmetric theories, the steep S-wave (slow P-wave) rise of the cross section for any non-diagonal neutralino pair production in $e^+ e^-$ annihilation, $e^+e^- \to \tildeχ^0_i \tildeχ^0_j$ ($i \neq j$), near threshold is accompanied by the slow P-wave (steep S-wave) decrease of the fermion invariant mass distribution of the 3-body ne

M. Benacquista, D. Sedrakian, M. Hairapetyan, K. Shahabasyan

Rotating white dwarfs undergoing quasi-radial oscillations can emit gravitational radiation in a frequency range from 0.1 - 0.3 Hz. Assuming that the energy source for the gravitational radiation comes from the oblateness of the white dwarf induced by the rotation, the strain amplitude is found to be \sim 10^{-27} for a white dwarf at \sim 50 pc. The galacti

Detlef Dürr, Sheldon Goldstein, Nino Zanghí

The quantum formalism is a ``measurement&#39;&#39; formalism--a phenomenological formalism describing certain macroscopic regularities. We argue that it can be regarded, and best be understood, as arising from Bohmian mechanics, which is what emerges from Schrödinger&#39;s equation for a system of particles when we merely insist that ``particles&#39;&#39; me

Detlef Dürr, Sheldon Goldstein, Nino Zangh\`ı

Bohmian mechnaics is the most naively obvious embedding imaginable of Schrödingers&#39;s equation into a completely coherent physical theory. It describes a world in which particles move in a highly non-Newtonian sort of way, one which may at first appear to have little to do with the spectrum of predictions of quantum mechanics. It turns out, however, that

Stefan Weigert, Paul Busch

Lueders theorem states that two observables commute if measuring one of them does not disturb the measurement outcomes of the other. We study measurements which are described by continuous positive operator-valued measurements (or POVMs) associated with coherent states on a Lie group. In general, operators turn out to be invariant under the Lueders map if th

Jiangfeng Du, Hui Li, Chenyong Ju

We investigate quantum games in which the information is asymmetrically distributed among the players, and find the possibility of the quantum game outperforming its classical counterpart depends strongly on not only the entanglement, but also the informational asymmetry. What is more interesting, when the information distribution is asymmetric, the contradi

Afsar Abbas

Recent experiments clearly demonstrate the importance of the excited state $2^+$ at 1.8 MeV in the substruture ${^6}He$ for the ground state of the nucleus ${^8}He$. It is shown here that this means that the ground state structure of ${^8}He$ rather than being $α$ + 4n is actually ${^3}H$ + ${^3}H$ +2n. As such the pair of tritons would form a compact core a

V. G. Dmitriev, R. Singh

Theoretical analysis is presented on quantum state evolution of polarization light waves at frequencies $ω_{o}$ and $ω_{e}$ in a periodically poled nonlinear crystal (PPNC). It is shown that the variances of all the four Stokes parameters can be squeezed.

Claudio Conti, Marco Peccianti, Gaetano Assanto

We develop a general theory of spatial solitons in a liquid crystalline medium exhibiting a nonlinearity with an arbitrary degree of effective nonlocality. The model accounts the observability of &#34;accessible solitons&#34; and establishes an important link with parametric solitons.

Pi-Gang Luan, Yee-Mou Kao

We study the continuous limit of a multibox Erhenfest urn model proposed before by the authors. The evolution of the resulting continuous system is governed by a differential equation, which describes a diffusion process on a circle with a nonzero drifting velocity. The short time behavior of this diffusion process is obtained directly by solving the equatio

Stefan Huller, Andrei Maximov, Denis Pesme

An efficient method to describe the nonlinear evolution of Stimulated Brillouin Scattering in long scale-length plasmas is presented. The method is based on a decomposition of the hydrodynamics variables in long- and short-wavelength components. It makes it possible to describe the self-consistent coupling between the plasma hydrodynamics, Stimulated Brillou

Alexander I. Shlyakhter

[NOTE: This 1983 preprint is being uploaded to arXiv.org after the death of its author, who supported online distribution of his work. Contact info of the submitter is at http://ilya.cc .] The positions of neutron resonances have been shown to be highly sensitive to the variation of fundamental nuclear constants. The analysis of the measured isotopic shifts

Scott Pratt

Results for correlations and fluctuations presented at Quark Matter 2002 are summarized. These results include Hanbury-Brown Twiss interferometry of a wide variety of species, large scale fluctuations and correlations in $p_t$ and multiplicity, and charge fluctuations and charge balance functions.

Zhong-Yu Ma, Bao-Qiu Chen, Nguyen Van Giai, Toshio Suzuki

Gamow-Teller(GT) resonances in finite nuclei are studied in a fully consistent relativistic random phase approximation (RPA) framework. A relativistic form of the Landau-Migdal contact interaction in the spin-isospin channel is adopted. This choice ensures that the GT excitation energy in nuclear matter is correctly reproduced in the non-relativistic limit.

Bertrand Bouriquet, Yasuhisa Abe, David Boilley

A new dynamical cascade code for decaying hot nuclei is proposed and specially adapted to the synthesis of super-heavy nuclei. For such a case, the interesting channel is the tiny fraction that will decay through particles emission, thus the code avoids classical Monte-Carlo methods and proposes a new numerical scheme. The time dependence is explicitely take