January 2001 arXiv papers — page 22

M. L. Dalla Chiara, R. Giuntini

We investigate some forms of quantum logic arising from the standard and the unsharp approach.

Elena Castellani

In recent years, a change in attitude in particle physics has led to our understanding current quantum field theories as effective field theories (EFTs). The present paper is concerned with the significance of this EFT approach, especially from the viewpoint of the debate on reductionism in science. In particular, it is a purpose of this paper to clarify how

Y. Fujiwara, T. Fujita, M. Kohno, C. Nakamoto

We upgrade a SU_6 quark-model description for the nucleon-nucleon and hyperon-nucleon interactions by improving the effective meson-exchange potentials acting between quarks. For the scalar- and vector-meson exchanges, the momentum-dependent higher-order term is incorporated to reduce the attractive effect of the central interaction at higher energies. The s

P. Chung, N. N. Ajitanand, J. M. Alexander, M. Anderson

We have measured the sideward flow of neutral strange ($K^0_s$) mesons in 6 AGeV Au + Au collisions. A prominent anti-flow signal is observed for an impact parameter range (b $\lesssim 7$ fm) which spans central and mid-central events. Since the $K^0_s$ scattering cross section is relatively small in nuclear matter, this observation suggests that the in-medi

P. Chung, N. N. Ajitanand, J. M. Alexander, M. Anderson

Directed flow measurements for $Λ$-hyperons are presented and compared to those for protons produced in the same Au+Au collisions (2, 4, and 6 AGeV; $b < 5 - 6$ fm). The measurements indicate that $Λ$-hyperons flow consistently in the same direction and with smaller magnitudes than those of protons. Such a strong positive flow [for $Λ$s] has been predicted i

J. Sawollek

A polynomial invariant of virtual links, arising from an invariant of links in thickened surfaces introduced by Jaeger, Kauffman, and Saleur, is defined and its properties are investigated. Examples are given that the invariant can detect chirality and even non-invertibility of virtual knots and links. Furthermore, it is shown that the polynomial satisfies a

Yuri G. Zarhin

We prove that in odd characteristic the jacobian of a hyperelliptic curve $y^2=f(x)$ has no nontrivial endomorphisms over an algebraic closure of the ground field if the Galois group of the polynomial $f$ of even degree is ``very big&#34;. The case of characteristic zero was previously treated by the author (Math. Res. Letters 7(2000), 123--132).

Pavel Etingof, Shlomo Gelaki

Recall that a triangular Hopf algebra A is said to have the Chevalley property if the tensor product of any two simple A-modules is semisimple, or, equivalently, if the radical of A is a Hopf ideal. There are two reasons to study this class of triangular Hopf algebras: First, it contains all known examples of finite-dimensional triangular Hopf algebras; seco

T. Barakat, M. Chabab

We study Dick quark-antiquark potential (up to a color factor) $V_D(r)={-α_s \over r} + gf \sqrt{N_c \over {2(N_c-1)}} \ln[exp(2mr)-1]$ in the heavy meson sector. This potential emerges from an effective dilaton-gluon coupling inspired from string theory and proves to be linearly rising at large distances which ensures quark confinement. The semi-relativisti

Marek Pawlowski, Victor Pervushin, Denis Proskurin

The paper is devoted to the description of the reparametrization - invariant dynamics of general relativity obtained by resolving constraints and constructing equivalent unconstrained systems. The constraint-shell action reveals the &#34;field nature&#34; of the geometric time in general relativity. The time measured by the watch of an observer coincides wit

S. Pokrant

Magnetic properties of Dy_N clusters in a molecular beam generated with a liquid helium cooled nozzle are investigated by Stern-Gerlach experiments. The cluster magnetizations μ_z are measured as a function of magnetic field (B = 0 - 1.6T) and cluster size (16 < N < 56). The most important observation is the saturation of the magnetization μ_z(B) at large fi

D. Yu. Vodolazov, I. L. Maksimov, E. H. Brandt

The conditions for the entry of vortices into type-II superconductors being in the Meissner and/or mixed state, are studied by both numerical and analytical solution of the Ginzburg-Landau equations. A modulation instability of the superconducting order parameter is shown to occur when the kinematic momentum (or supervelocity) of the condensate reaches a thr

V. V. Popov, T. V. Teperik

The polarisation conversion of a linear polarised electromagnetic wave incident onto a two-dimensional (2D) electron system at an angle is theoretically studied. We consider the 2D system located at the interface between two dielectric media with different dielectric constants. An external dc magnetic field is assumed to be directed along the normal to the 2

Emily S. C. Ching, K. L. Chau

We find that the conditional statistics of temperature difference at fixed values of the locally averaged temperature dissipation rate in turbulent convection become Gaussian in the regime where the mixing dynamics is expected to be driven by buoyancy. Hence, intermittency of the temperature fluctuations in this buoyancy-driven regime can be solely attribute

Mukul S. Laad, J. R. Reyes Martinez

Based on a perusal of available experimental data, we propose a possible explanation for the heavy-fermion Fermi liquid state coexisting with quasi-one dimensional antiferromagnetism in the low-carrier pnictide Yb_{4}As_{3}. Both of these low temperature features are shown to originate from one single fact - the charge ordered state forming at high-T is impe

Sumiyoshi Abe

Macroscopic nonextensive thermodynamics is studied without recourse to microscopic statistical mechanics. It is shown that if entropy is nonextensive, the concept of physical temperature introduced through the generalized zeroth law of thermodynamics necessarily leads to modifications of the first law of thermodynamics and some of thermodynamic relations inc

Masatoshi Imanishi

Thermal infrared photometry in the $L$- and $M&#39;$-band and $L - M&#39;$ colors of type-1 and type-2 active galactic nuclei (AGNs) are presented. After combining our observations with photometric data at similar wavelengths taken from the literature, we find that the excess of $L - M&#39;$ colors of type-2 AGNs (37 sources, 50 data points) relative to type

Christian Schubert

We review the status and present range of applications of the ``string-inspired&#39;&#39; approach to perturbative quantum field theory. This formalism offers the possibility of computing effective actions and S-matrix elements in a way which is similar in spirit to string perturbation theory, and bypasses much of the apparatus of standard second-quantized f

S. James Gates,, Hitoshi Nishino

In relation to the superspace modifications of 11D supergeometry required to describe the M-theory low-energy effective action, we present an analysis of infinitesimal supergravity fluctuations about the flat superspace limit. Our investigation confirms Howe&#39;s interpretation of our previous Bianchi identity analysis. However, the analysis also shows that

Jonathan L. Rosner, Denis A. Suprun

A prototype system for detecting radio pulses associated with extensive cosmic ray air showers is described. Sensitivity is compared with that in previous experiments, and lessons are noted for future studies.

D. Dalmazi, J. J. M. Verbaarschot

We derive Virasoro constraints for the zero momentum part of the QCD-like partition functions in the sector of topological charge $ν$. The constraints depend on the topological charge only through the combination $N_f +βν/2$ where the value of the Dyson index $β$ is determined by the reality type of the fermions. This duality between flavor and topology is i

Luis Bento

One examines the interaction and possible resonances between supernova neutrinos and electron plasma waves. The neutrino phase space distribution and its boundary regions are analyzed in detail. It is shown that the boundary regions are too wide to produce non-linear resonant effects. The growth or damping rates induced by neutrinos are always proportional t

Martin White

The detection of anisotropy in the cosmic microwave background on arcminute scales by the Cosmic Background Imager (CBI) provides us with our first measurement of the damping tail and closes one chapter in the CMB story. We now have experimental verification for all of the features in the temperature anisotropy spectrum predicted theoretically two decades ag

L. Cappiello, G. Cristofano, G. Maiella, V. Marotta

We argue that a system of interacting D-branes, generalizing a recent proposal, can be modelled as a Quantum Hall fluid. We show that tachyon condensation in such a system is equivalent to one particle tunnelling. In a conformal field theory effective description, that induces a transition from a theory with central charge c=2 to a theory with c=3/2, with a

L. S. Kisslinger, Ho-Meoyng Choi, Chueng-Ryong Ji

We discuss the soft contribution to the elastic pion form factor with the mass evolution from current to constituent quark being taken into account using a light-front Bethe-Salpeter (LFBS) model, which is a light-front quark model (LFQM) with a running mass. It is shown that partial conservation of the axial-vector current (PCAC) is satisfied with a running

Cedric R. Leao, Victor O. Rivelles

The classical equations of motion of Maxwell and Born-Infeld theories are known to be invariant under a duality symmetry acting on the field strengths. We implement the SL(2,Z) duality in these theories as linear but non-local transformations on the potentials. We show that the action and the partition function in the Hamiltonian formalism are modular invari

Esteban Calzetta, Albert Roura, Enric Verdaguer

We study the process of vacuum decay in quantum field theory focusing on the stochastic aspects of the interaction between long and short-wavelength modes. This interaction results in a diffusive behavior of the reduced Wigner function describing the state of the long-wavelength modes, and thereby to a finite activation rate even at zero temperature. This ef

D. Stump, J. Pumplin, R. Brock, D. Casey

We apply the Lagrange Multiplier method to study the uncertainties of physical predictions due to the uncertainties of parton distribution functions (PDFs), using the cross section for W production at a hadron collider as an archetypal example. An effective chi-squared function based on the CTEQ global QCD analysis is used to generate a series of PDFs, each

Jaromir Fiurasek

Maximum likelihood estimation is applied to the determination of an unknown quantum measurement. The measuring apparatus performs measurements on many different quantum states and the positive operator-valued measures governing the measurement statistics are then inferred from the collected data via Maximum-likelihood principle. In contrast to the procedures

Arjun Berera, Rudnei O. Ramos

The zero temperature effective equation of motion is derived for a scalar field interacting with other fields. For a broad range of cases, involving interaction with as few as one or two fields, dissipative regimes are found for the scalar field system. The zero temperature limit constitutes a baseline effect that will be prevalent in any general statistical

Bumsoo Kyung

In this paper we show that local spin-singlet amplitude with d-wave symmetry, $<|Δ_{d}(0)|^{2}>$, can be induced by short-range spin correlations even in the absence of pairing interactions. Fluctuation theory is formulated to make connection between pseudogap temperature $T^{*}$, pseudogap size $Δ_{pg}$ and $<|Δ_{d}(0)|^{2}>$. In the present scenario for th

E. M. Gregores, A. Gusso, S. F. Novaes

We show that the accumulated LEP-II data taken at $\sqrt{s} =$ 130 to 206 GeV can establish more restrictive bounds on doubly charged bileptons couplings and masses than any other experiment so far. We also analyze the discovery potential of a prospective linear collider operating in both $e^+ e^-$ and $e γ$ modes.

Georg Foltin

We extend a Gaussian model for the internal electrical potential of a two-dimensional Coulomb gas by a non-Gaussian measure term, which singles out the physically relevant configurations of the potential. The resulting Hamiltonian, expressed as a functional of the internal potential, has a surprising large-scale limit: The additional term simply counts the n

D. Jaksch, S. A. Gardiner, K. Schulze, J. I. Cirac

The relative phase of two initially independent Bose-Einstein condensates can be laser cooled to unite the two condensates by putting them into a ring cavity and coupling them with an internal Josephson junction. First, we show that this phase cooling process already appears within a semiclassical model. We calculate the stationary states, find regions of bi

Philippe Jund, Walter Kob, Remi Jullien

We use classical molecular dynamics simulations to study the dynamics of sodium atoms in amorphous Na$_2$O-4SiO$_2$. We find that the sodium trajectories form a well connected network of pockets and channels. Inside these channels the motion of the atoms is not cooperative but rather given by independent thermally activated hops of individual atoms between t

F. Iwamuro, K. Motohara, T. Maihara, R. Hata

This paper describes an OH-airglow Suppressor (OHS) for the infrared Nasmyth focus of the Subaru telescope. OHS has the capability of eliminating 224 airglow-lines in the $J$- and $H$-bands, which are major sources of background radiation at near-infrared wavelengths up to 2 $μ$m. Specifically, it is a pre-optics system installed between the telescope and an

Dan Pirjol

We report on recent progress on perturbative QCD calculations of certain exclusive rare weak $B$ meson decays involving hard photons. In the limit of a photon energy $E_γ$ much larger than $Λ_{QCD}$, the amplitudes for such processes can be analyzed in a twist expansion in powers of $Λ/E_γ$. The leading twist amplitude is given by the convolution of a hard s

A. K. Khitrin, B. M. Fung

The propagation of excitation along a one-dimensional chain of atoms is simulated by means of NMR. The physical system used as an analog quantum computer is a nucleus of 133-Cs (spin 7/2) in a liquid crystalline matrix. The Hamiltonian of migration is simulated by using a special 7-frequency pulse, and the dynamics is monitored by following the transfer of p

Jeremy Levy

I describe a proposal to construct a quantum information processor using ferroelectrically coupled Ge/Si quantum dots. The spin of single electrons form the fundamental qubits. Small (<10 nm diameter) Ge quantum dots are optically excited to create spin polarized electrons in Si. The static polarization of an epitaxial ferroelectric thin film confines electr

J. -P. Laval, B. Dubrulle, S. Nazarenko

We present numerical simulation of 2D turbulent flow using a new model for the subgrid scales which are computed using a dynamic equation linking the subgrid scales with the resolved velocity. This equation is not postulated, but derived from the constitutive equations under the assumption that the non-linear interactions of subgrid scales between themselves

J. -P. Laval, B. Dubrulle, S. Nazarenko

Numerical simulations are used to determine the influence of the non-local and local interactions on the intermittency corrections in the scaling properties of 3D turbulence. We show that neglect of local interactions leads to an enhanced small-scale energy spectrum and to a significantly larger number of very intense vortices (tornadoes) and stronger interm

V. N. Oraevsky, Yu. Ya. Ruzhin, V. I. Badin, M. G. Deminov

An analysis of the Alfven wave generation associated with the barium vapor release at altitudes ~ 5.2 Earth&#39;s radii (ER) in the magnetosphere is presented. Such injections were executed in G-8 and G-10 experiments of the Combined Radiation and Radiation Effects Satellite (CRRES) mission. It is shown that the generation of Alfven waves is possible during

Nikolay A. Zabotin, Andrey G. Bronin, Vladimir L. Frolov, Georgy P. Komrakov

Multiple scattering of radio waves by artificial random irregularities HF-induced in the ionosphere F region may cause significant attenuation of both ordinary and extraordinary waves together with common anomalous absorption of ordinary waves due to their non-linear conversion into plasma waves. To demonstrate existence and strength of this effect, direct m

A. Neumaier, V. A. Mandelshtam

The Schroedinger equation with an energy-dependent complex absorbing potential, associated with a scattering system, can be reduced for a special choice of the energy-dependence to a harmonic inversion problem of a discrete pseudo-time correlation function. An efficient formula for Green&#39;s function matrix elements is also derived. Since the exact propaga

Nikolay A. Zabotin, Andrey G. Bronin, Gennady A. Zhbankov

The paper presents formulation and solution for the problem of determination of spatial spectrum of artificial ionospheric irregularities from vertical HF radio sounding data on anomalous attenuation. The suggested method uses the dependence of extraordinary wave attenuation caused by multiple scattering from the irregularities on frequency to obtain the spe

Yu-Jun Chen, H. R. Ma

A theory is developed for magnetically confined Fermi gas at low temperature based on the density functional theory. The theory is illustrated by numerical calculation of density distributions of Fermi atoms $^{40}$K with parameters according to DeMarco and Jin&#39;s experiment[Science, 285(1999)1703]. Our results are in good agreement with the experiment. T

Stefan Hobai

The titration solubilization of multilamellar egg-yolk lecithin liposomes (MLV-EYL) with Triton X-100 was studied by rectangular optical diffusimetric measurements as a function of cholesterol (Chol) concentration. It was determinated the variation of optic percentage diffu-sion (per mmol surfactant), DDif%/mmol TX-100, in the course of solubilization of MLV

Stefan Hobai

It were determinated the apparent activating energy of dipalmitoylphosphatidylcholine (DPPC) multilamellar liposome (MLV) solubilizing with sodium deoxycholate (DOCNa) by turbidi-metric measurements and the apparent activating energy of egg-yolk lecithin (EYL)- MLV solubilizing with different surfactants (DOCNa, TX-100, CTMB) by rectangular optic diffu-si-me

Stefan Hobai

The effect of solute, sodium deoxycholate bile salt (DOCNa), on the cooperativity of ordered-fluid, fosfolipid phase transition has been investigated by determining of the transition widths in multibilayer dispersions of the dipalmitoylphosphatidylcholine (DPPC)-DOCNa mixtures. The DT1/2 values were determined by differential scanning calorimetry. The van&#3

Antonina N. Fedorova, Michael G. Zeitlin

We present applications of variational -- wavelet approach to three different models of nonlinear beam motions with underlying collective behaviour: Vlasov-Maxwell-Poisson systems, envelope dynamics, beam-beam model. We have the representation for dynamical variables as a multiresolution (multiscales) expansion via high-localized nonlinear eigenmodes in the

Mikola I. Ayzatsky

It was usually assumed that the resonator based on a waveguide has the eigen oscillations that are formed by interference of two waves which propagate in different directions and have equal amplitudes. These patterns are usually called standing waves. We have shown that the eigen oscillations of a resonator which is filled by a layered dielectric can be base

Stefan Leupold

Extending previous work we study the constraints of QCD sum rules on mass and width of light vector and axial-vector mesons in vacuum and in a medium with finite nuclear density. For the latter case especially the effect of nuclear pions leading to vector-axial-vector mixing is included in the analysis.

Richard L. Hall, Nasser Saad, Attila B. von Keviczky

A variational and perturbative treatment is provided for a family of generalized spiked harmonic oscillator Hamiltonians H = -(d/dx)^2 + B x^2 + A/x^2 + lambda/x^alpha, where B > 0, A >= 0, and alpha and lambda denote two real positive parameters. The method makes use of the function space spanned by the solutions |n> of Schroedinger&#39;s equation for the p

Christian Maes, Frank Redig, Ellen Saada

We consider the standard Abelian sandpile process on the Bethe lattice. We show the existence of the thermodynamic limit for the finite volume stationary measures and the existence of a unique infinite volume Markov process exhibiting features of self-organized criticality.

Ian Agol, Darren D. Long, Alan W. Reid

We show that for certain arithmetic groups, geometrically finite subgroups are the intersection of finite index subgroups containing them. Examples are the Bianchi groups and the Seifert-Weber dodecahedral space. In particular, for manifolds commensurable with these groups, immersed incompressible surfaces lift to embeddings in a finite sheeted covering.

Christopher Connell, Benson Farb

We prove minimal entropy rigidity for complete, finite volume manifolds locally isometric to a product of rank one symmetric spaces of dimension at least 3: the locally symmetric metric uniquely minimizes (normalized) entropy among all Riemannian metrics. The corresponding theorem is true for maps into these spaces as well.

Christopher Connell, Benson Farb

Let M be any closed, locally symmetric n-manifold (n>1) of nonpositive curvature. Assume that M has no locally Euclidean factors and no factors locally isometric to SL(3,R). Then for any closed Riemannian manifold N and any continuous map f:N -> M, we show there is a C^1 representative in the homotopy class of f with Jacobian bounded by a universal constant

Dan Burghelea, Stefan Haller

We consider systems $(M,ω,g)$ with $M$ a closed smooth manifold, $ω$ a real valued closed one form and $g$ a Riemannian metric, so that $(ω,g)$ is a Morse-Smale pair, Definition~2. We introduce a numerical invariant $ρ(ω,g)\in[0,\infty]$ and improve Morse-Novikov theory by showing that the Novikov complex comes from a cochain complex of free modules over a s

Grigori Litvinov

Several construction methods for rational approximations to functions of one real variable are described in the present paper; the computational results that characterize the comparative accuracy of these methods are presented; an effect of error autocorrection is considered. This effect occurs in efficient methods of rational approximation (e.g., Pade appro

Florin Panaite

Let A be a finite dimensional Hopf algebra and (H, R) a quasitriangular bialgebra. Denote by H^*_R a certain deformation of the multiplication of H^* via R. We prove that H^*_R is a quantum commutative left H\otimes H^{op cop}-module algebra. If H is the Drinfel&#39;d double of A then H^*_R is the Heisenberg double of A. We study the relation between H^*_R a

Daniel S. Freed

In joint work with M. Hopkins and C. Teleman we find a new description of the Verlinde algebra associated to a compact Lie group. In this expository account we describe twisted K-theory, prove the theorem for the group SU(2), and motivate the general theorem using ideas in topological field theory. The full proof will appear elsewhere.

Stephen Doty, Anthony Giaquinto

We obtain a presentation of quantum Schur algebras (over the field Q(v)) by generators and relations. This presentation is compatible with the usual presentation of the quantized universal enveloping algebra of the Lie algebra gl(2). We also locate the ``integral&#39;&#39; form of the quantum Schur algebra within the presented algebra and show it has a basis

Paul Fendley

Sigma models arise frequently in particle physics and condensed-matter physics as low-energy effective theories. In this paper I compute the exact free energy at any temperature in two hierarchies of integrable sigma models in two dimensions. These theories, the SU(N)/SO(N) and O(2P)/O(P) x O(P) models, are asymptotically free and exhibit charge fractionaliz

V. A. Dolgushev, S. L. Lyakhovich, A. A. Sharapov

A coordinate-free definition for Wick-type symbols is given for symplectic manifolds by means of the Fedosov procedure. The main ingredient of this approach is a bilinear symmetric form defined on the complexified tangent bundle of the symplectic manifold and subject to some set of algebraic and differential conditions. It is precisely the structure which de

Israel Quiros

A very simple mechanism is proposed that stabilizes the orbifold geometry within the context of the Randall-Sundrum proposal for solving the hierarchy problem. The electroweak TeV scale is generated from the Planck scale by spontaneous breaking of the orbifold symmetry

P. Cea, M. Consoli, L. Cosmai

Recent lattice simulations of $(λΦ^4)_4$ theories in the broken phase show that : a) the shifted field propagator is well reproduced by the simple 2-parameter form ${Z_{\rm prop}\over{p^2 + M^2_h}}$ at finite momenta but strongly differs for $p \to 0$ b) the bare zero-momentum two-point function $Γ_2(0)= \frac{d^2 V_{\rm eff}}{d ϕ^2_B}|_{ϕ_B= \pm v_B}$ gives

J. -M. Laget

After pioneering works on hypernuclei, strangeness production mechanisms have been studied in hadron collisions and photoreactions in the sixties. Recent experiments at SATURNE and COSY, in the hadronic sector, as well as ELSA and JLab, in the electromagnetic sector, have confirmed our basic ideas on the reaction mechanisms. In the near future, strangeness p

K. S. Babu, Yukihiro Mimura

We suggest a solution to the μproblem of gauge mediated supersymmtery breaking models based on flavor symmetries. In this scenario the μterm arises through the vacuum expectation value of a singlet scalar field which is suppressed by a flavor symmetry factor relative to the scale of dynamical SUSY breaking. The same flavor symmetry also ensures that the soft

Gordon P. Ramsey

The absence of &#34;valence-gluon&#34; degrees of freedom combined with an examination of radiative QCD diagrams leads to an implication that the gluon spin asymmetry in a proton, defined as A_G(x,Q^2) = (Delta G)/G, should be approximately Q^2 invariant. The condition for scale invariance completely determines the x-dependence of this asymmetry, which satis

D. O. Caldwell, R. N. Mohapatra, S. J. Yellin

A desirable feature of models with large extra dimensions and a TeV range string scale is the possibility to understand an ultralight sterile neutrino needed for a simultaneous understanding of solar, atmospheric and LSND results as a Kaluza-Klein state of a bulk neutrino. How these oscillation data are understood in quantitative detail is still not clear. W

I. Balitsky

At high energies the particles move very fast so their trajectories can be approximated by straight lines collinear to their velocities. The proper degrees of freedom for the fast gluons moving along the straight lines are the Wilson-line operators -- infinite gauge factors ordered along the straight line. I review the study of the high-energy scattering in

G. Sciolla, representing the The BABAR Collaboration

The BaBar experiment and the PEP-II accelerator at SLAC started to take data on May 26, 1999. By the time of this conference, the recorded integrated luminosity was 20 fb^{-1}, of which 8 fb^{-1} were analyzed to provide a first set of physics results. This talk reviews the first measurement of sin2beta and the study of B meson decays to charmonium modes and

Scott A. Hughes

In this comment, I argue that chaotic effects in binary black hole inspiral will not strongly impact the detection of gravitational waves from such systems.

Scott A. Hughes

An unusual set of orbits about extreme Kerr black holes resides at the Boyer-Lindquist radius $r = M$, the coordinate of the hole&#39;s event horizon. These ``horizon skimming&#39;&#39; orbits have the property that their angular momentum $L_z$ {\it increases} with inclination angle, opposite to the familiar behavior one encounters at larger radius. In this

P. Tricarico, A. Ortolan, A. Solaroli, G. Vedovato

The cosmological origin of $γ$-ray bursts (GRBs) is now commonly accepted and, according to several models for the central engine, GRB sources should also emit at the same time gravitational waves bursts (GWBs). We have performed two correlation searches between the data of the resonant gravitational wave detector AURIGA and GRB arrival times collected in th

Marc Mars

Based on a geometrical property which holds both for the Kerr metric and for the Wahlquist metric we argue that the Kerr metric is a vacuum subcase of the Wahlquist perfect-fluid solution. The Kerr-Newman metric is a physically preferred charged generalization of the Kerr metric. We discuss which geometric property makes this metric so special and claim that

Marc Mars

The spacetime Ehlers group, which is a symmetry of the Einstein vacuum field equations for strictly stationary spacetimes, is defined and analyzed in a purely spacetime context (without invoking the projection formalism). In this setting, the Ehlers group finds its natural description within an infinite dimensional group of transformations that maps Lorentz

C. Cartier, E. J. Copeland, M. Gasperini

We study the evolution of tensor metric fluctuations in a class of non-singular models based on the string effective action, by including in the perturbation equation the higher-derivative and loop corrections needed to regularise the background solutions. We discuss the effects of such higher-order corrections on the final graviton spectrum, and we compare

J. A. Vickers, J. P. Wilson

Sufficient conditions for the well-posedness of the initial value problem for the scalar wave equation are obtained in space-times with hypersurface singularities

Liao Liu, Feng He

We show that the bubbles $S^2\times S^2$can be created from vacuum fluctuation in certain De Sitter universe, so the space-time foam-like structure might really be constructed from bubbles of $S^2\times S^2$ in the very early inflating phase of our universe. But whether such foam-like structure persisted during the later evolution of the universe is a proble

Kevin K. H. Cheung, Michele Mosca

This paper describes a quantum algorithm for efficiently decomposing finite Abelian groups. Such a decomposition is needed in order to apply the Abelian hidden subgroup algorithm. Such a decomposition (assuming the Generalized Riemann Hypothesis) also leads to an efficient algorithm for computing class numbers (known to be at least as difficult as factoring)

Yasuhiro Ajiro, Kazunori Ueda

We have implemented Kima, an automated error correction system for concurrent logic programs. Kima corrects near-misses such as wrong variable occurrences in the absence of explicit declarations of program properties. Strong moding/typing and constraint-based analysis are turning to play fundamental roles in debugging concurrent logic programs as well as in

William Garber, Folkert M. Tangerman, Philip B. Allen, Joseph L. Feldman

Numerical studies of amorphous silicon in harmonic approximation show that the highest 3.5% of vibrational normal modes are localized. As vibrational frequency increases through the boundary separating localized from delocalized modes, near omega_c=70meV, (the &#34;mobility edge&#34;) there is a localization-delocalization (LD) transition, similar to a secon

P. A. Shields, R. J. Nicholas, N. Grandjean, J. Massies

A re-ordered valence band in GaN/AlGaN quantum wells with respect to GaN epilayers has been found as a result of the observation of an enhanced g-factor in magneto-luminescence spectra in fields up to 55 T. This has been caused by a reversal of the states in the strained AlGaN barriers thus giving different barrier heights for the different quantum well hole

Z. Burda, D. Johnston, J. Jurkiewicz, M. Kaminski

We discuss a Pareto macro-economy (a) in a closed system with fixed total wealth and (b) in an open system with average mean wealth and compare our results to a similar analysis in a super-open system (c) with unbounded wealth. Wealth condensation takes place in the social phase for closed and open economies, while it occurs in the liberal phase for super-op

Igor F. Lyuksyutov, H. -U. Everts, H. Pfnuer

We study the collective diffusion in chain structures on anisotropic substrates like (112) bcc and (110) fcc surfaces with deep troughs in the substrate potential corrugation. These chain structures are aligned normal to the troughs and can move only along the troughs. In a combination of theoretical arguments and of numerical simulations, we study the mass

R. Melzi, S. Aldrovandi, F. Tedoldi, P. Carretta

NMR, muSR, magnetization and specific heat measurements in Li(2)VOSiO(4) powders and single crystals are reported. Specific heat and magnetization measurements evidence that Li(2)VOSiO(4) is a frustrated two-dimensional S=1/2 Heisenberg antiferromagnet on a square lattice with a superexchange coupling J_1, along the sides of the square, almost equal to J_2,

Henrik Jeldtoft Jensen, Mario Nicodemi

Vortex flow in driven type II superconductors shows strong memory and history dependent effects. Here, we study a schematic microscopic model of driven vortices to propose a scenario for a broad set of these kind of phenomena ranging from ``rejuvenation&#39;&#39; and ``stiffening&#39;&#39; of the system response, to ``memory&#39;&#39; and ``irreversibility&#

Christian Maes

This is a short review of the statistical mechanical definition of entropy production for systems composed of a large number of interacting components. Emphasis is on open systems driven away from equilibrium where the entropy production can be identified with a logarithmic ratio of microstate multiplicities of the original macrostate with respect to the tim

Yu. G. Naidyuk, O. E. Kvitnitskaya, A. G. M. Jansen, C. Geibel

The antiferromagnetic (AFM) state has been investigated in the three heavy-fermion compounds URu2Si2, UPd2Al3, and UNi2Al3 by measuring dV/dI(V) curves of point contacts at different temperatures (1.5-20 K) and magnetic fields (0-28 T). The zero-bias maximum in dV/dI(V) for URu2Si2 points to a partially gapped Fermi-surface related to the itinerant nature of

D. W. Wang, S. Das Sarma

We systematically investigate the mode dispersion and spectral weight of the elementary excitation spectra in one-dimensional continuum and lattice electron systems by using the RPA, the Luttinger liquid model, and the Hubbard model. Both charge and spin excitations are studied in details and compared among the theoretical models. For the lattice Hubbard mod

S. E. Skipetrov

We consider the multiple scattering of a scalar wave in a disordered medium with a weak nonlinearity of Kerr type. The perturbation theory, developed to calculate the temporal autocorrelation function of scattered wave, fails at short correlation times. A self-consistent calculation shows that for nonlinearities exceeding a certain threshold value, the multi

T. Garel, C. Monthus, H. Orland

Following Poland and Scheraga, we consider a simplified model for the denaturation transition of DNA. The two strands are modeled as interacting polymer chains. The attractive interactions, which mimic the pairing between the four bases, are reduced to a single short range binding term. Furthermore, base-pair misalignments are forbidden, implying that this b

Yuo-Hsien Shiau, Chin-Kun Hu

We analytically study the photorefractive Gunn effect in n-GaAs subjected to two external laser beams which form a moving interference pattern (MIP) in the semiconductor. When the intensity of the spatially independent part of the MIP, denoted by $I_0$, is small, the system has a periodic domain train (PDT), consistent with the results of linear stability an

Kazuhisa Kaneda, Yutaka Okabe

We study the finite-size scaling properties of the Ising model on the Moebius strip and the Klein bottle. The results are compared with those of the Ising model under different boundary conditions, that is, the free, cylindrical, and toroidal boundary conditions. The difference in the magnetization distribution function $p(m)$ for various boundary conditions

Xiaoyu Xia, Peter G. Wolynes

The description of molecular motion by macroscopic hydrodynamics has a long and continuing history. The Stokes-Einstein relation between the diffusion coefficient of a solute and the solvent viscosity predicted using macroscopic continuum hydrodynamics, is well satisfied for liquids under ordinary to high temperature conditions, even for solutes as small as

E. Miranda, V. Dobrosavljevic

We demonstrate that local density of states fluctuations in disordered Anderson lattice models universally lead to the emergence of non-Fermi liquid (NFL) behavior. The NFL regime appears at moderate disorder (W = W_c) and is characterized by power-law anomalies, e. g. C/T ~ 1/T^{(1-α)}, where the exponent αvaries continuously with disorder, as in other Grif

Seth Redfield, Jeffrey L. Linsky

We analyze high-resolution UV spectra of the Mg II h and k lines for 18 members of the Hyades Cluster to study inhomogeneity along these proximate lines of sight. The observations were taken by the Space Telescope Imaging Spectrograph (STIS) instrument on board the Hubble Space Telescope (HST). Three distinct velocity components are observed. All 18 lines of

W. Raphael Hix, Michael S. Smith, Anthony Mezzacappa, Sumner Starrfield

The nucleosynthesis and other observable consequences of a nova outburst depend sensitively on the details of the thermonuclear runaway which initiates the outburst. One important source of uncertainty in our current models is the nuclear reaction data used as input for the evolutionary calculations. We present preliminary results of the first analyses of th

James C. Lombardi, Frederic A. Rasio

We review recent 3D hydrodynamic calculations of stellar collisions using the Smoothed Particle Hydrodynamics (SPH) method, and we discuss the implications of the results for the formation and evolution of blue stragglers in globular clusters. We also discuss the construction of simple analytic models for merger remnants, approximating the mass loss, shock h