arXiv papers from January 1995

Yun Wang

We present two simple analytical methods for computing the gravity wave contribution to the cosmic background radiation (CBR) anisotropy in inflationary models; one method uses a time-dependent transfer function, the other method uses an approximate gravity-wave mode function which is a simple combination of the lowest order spherical Bessel functions. We co

Joseph Bernstein

The series of three lectures given at Tel-Aviv University in 1992: 1. Tensor categories. 2. Quantum groups. 3. Topological (quantum) field theories. Published as the preprint IAS 897-92 of Tel-Aviv University and The Mortimer and Raymond Sacler Institute of Advanced Studies.

Bruno IOCHUM, Thomas SCHÜCKER

By a suitable choice of variables we show that every Connes-Lott model is a Yang-Mills-Higgs model. The contrary is far from being true. Necessary conditions are given. Our analysis is pedestrian and illustrated by examples.

M. -T. Dova, L. N. Epele, H. Fanchiotti, C. A. Garcia Canal

A method is presented to extract the tau neutrino helicity, or equivalently, the chirality parameter $\gamma_{\mathrm{VA}}$, independent of any tau polarization which may be present. The method is thus well-suited to measurements using taus produced from the $Z^0$ and is complementary to analyses using tau correlations since it provides the sign of the chira

J. D. Swain

The final states for the process $b \rightarrow s\ \gamma$ have been extensively discussed in the literature. Similarly-detailed analyses for the case $b \rightarrow s\ gluon$ have not been performed. Generally this process is searched for in 2-body decays such as ${\rm B}^0 \rightarrow {\rm K}^+ \pi^-$. We present simple arguments to suggest that most of th

C. Barnes, B. L Johnson, G. Kirczenow

We present a study of the transport properties of a general class of quantum mechanical waveguides: Quantum Railroads (QRR). These waveguides are characterised by having a different number of adiabatic modes which carry current in one direction along the waveguide to the opposite direction; for example N forward modes and M reverse modes. Just as Anderson lo

H. Høgaasen, F. Myhrer

We reevaluate a quark model prediction using the new QCD evolution function calculated to the 3 loop order and conclude that this model compares favorably with the new experimental results.

Jnanadeva Maharana

The ten dimensional heterotic string effective action with graviton, dilaton and antisymmetric tensor fields is dimensionally reduced to two spacetime dimensions. The resulting theory, with some constraints on backgrounds, admits infinite sequence of conserved nonlocal currents. It is shown that generators of the infinitesimal transformations associated with

Jnanadeva Maharana

A two dimensional string effective action is obtained by dimensionally reducing the bosonic part of the ten dimensional heterotic string effective action. It is shown that this effective action, with a few restrictions on some backgrounds describes a two dimensional model which admits an infinite sequence of nonlocal conserved currents.

S. James Gates, Sergei V. Ketov

We generalize the standard $N=2$ supersymmetric Kazama-Suzuki coset construction to the $N=4$ case by requiring the {\it non-linear} (Goddard-Schwimmer) $N=4~$ quasi-superconformal algebra to be realized on cosets. The constraints that we find allow very simple geometrical interpretation and have the Wolf spaces as their natural solutions. Our results obtain

Rupak Chatterjee

It is shown that several Hamiltonian systems possessing dynamical or hidden symmetries can be realized within the framework of Nambu's generalized mechanics. Among such systems are the SU(n)-isotropic harmonic oscillator and the SO(4)-Kepler problem. As required by the formulation of Nambu dynamics, the integrals of motion for these systems necessarily becom

Enrique Gaztañaga, Rupert Croft, Gavin Dalton

We estimate the variance $\xibar_2$, the skewness $\xibar_3$ and the kurtosis $\xibar_4$ in the distribution of density fluctuations in a complete sample from the APM Cluster Redshift Survey with 339 clusters and a mean depth $ \sim 250\Mpc$. We are able to measure the statistics of fluctuations in spheres of radius $R \simeq 5-80 \Mpc$, with reasonable erro

S. Hands, S. Kim, J. B. Kogut

The four-fermi model with continuous chiral symmetry is studied in three dimensions at non-zero chemical potential $\mu$ using both the $1/N_f$ expansion and computer simulations. For strong coupling this model spontaneously breaks its U(1) chiral symmetry at zero chemical potential and the Goldstone mechanism is realized through massless pions. The computer

S. A. Frolov

It it known that to get the usual Hamiltonian formulation of lattice Yang-Mills theory in the temporal gauge $A_{0}=0$ one should place on every link the cotangent bundle of a Lie group. The cotangent bundle may be considered as a limiting case of a so called Heisenberg double of a Lie group which is one of the basic objects in the theory of Lie-Poisson and

Konrad Kuijken, Michael R. Merrifield

It has been suggested that the peanut-shaped bulges seen in some edge-on disk galaxies are due to the presence of a central bar. Although bars cannot be detected photometrically in edge-on galaxies, we show that barred potentials produce a strong kinematic signature in the form of double-peaked line-of-sight velocity distributions with a characteristic ``fig

Jens O. Andersen

The chiral Abelian Higgs model is studied at finite temperature. By integrating out the heavy modes, we make a three-dimensional effective theory for the static modes. It is demonstrated that the plasma masses are correctly reproduced to leading order in $m^{2}/T^{2}$. The effective potential for the composite operator $\phi^{\dagger}\phi$ is calculated at o

P Biscari, G Parisi

We study the statistical mechanics of a model describing the coevolution of species interacting in a random way. We find that at high competition replica symmetry is broken. We solve the model in the approximation of one step replica symmetry breaking and we compare our findings with accurate numerical simulations.

Oleg Y. Gnedin, Jeremy Goodman, Zsolt Frei

Spiral arms, if they are massive, exert gravitational torques that transport angular momentum radially within galactic disks. These torques depend not on the pattern speed or permanence of the arms but only on the nonaxisymmetric mass distribution. Hence the torques can be measured from photometry. We demonstrate this using $gri$ CCD data for M100 (NGC 4321)

I. Guarneri, K. Zyczkowski, J. Zakrzewski, L. Molinari

A Fourier analysis of parametric level dynamics for random matrices periodically depending on a phase is developed. We demonstrate both theoretically and numerically that under very general conditions the correlation $C(\varphi )$ of level velocities is singular at $\varphi =0$ for any symmetry class; the singularity is revealed by algebraic tails in Fourier

David H. Lyth

When considering perturbations in an open universe, cosmologists retain only sub-curvature modes (defined as eigenfunctions of the Laplacian whose eigenvalue is less than $-1$ in units of the curvature scale, in contrast with the super-curvature modes whose eigenvalue is between $-1$ and $0$). Mathematicians have known for almost half a century that all mode

V. M. Manuilov

It is known that the classical Hilbert--Schmidt theorem can be generalized to the case of compact operators in Hilbert $A$-modules $H_A^*$ over a $W^*$-algebra of finite type, i.e. compact operators in $H_A^*$ under slight restrictions can be diagonalized over $A$. We show that if $B$ is a weakly dense $C^*$-subalgebra of real rank zero in $A$ with some addi

Francois Andry, Mark Gawron, John Dowding, Robert Moore

In this paper, we describe a tool designed to generate semi-automatically the sortal constraints specific to a domain to be used in a natural language (NL) understanding system. This tool is evaluated using the SRI Gemini NL understanding system in the ATIS domain.

X. Gonze, Ph. Ghosez, R. W. Godby, .

The response of an infinite, periodic, insulating, solid to an infinitesimally small electric field is investigated in the framework of Density Functional Theory. We find that the applied perturbing potential is not a unique functional of the periodic density change~: it depends also on the change in the macroscopic {\em polarization}. Moreover, the dependen

S. A. Kiyanov-Charsky

We investigate a spectrum of the low-energy composite particles with the quantum numbers $J^p=0^\pm,\frac {1}{2}^\pm$ in a $SU_{F}(3)$ model of hadron supersymmetry. We derive the mass spectrum of two, three and four-quark states and determine all free parameters of a theory, including the masses of quarks and diquarks.

S. A. Kiyanov-Charsky

We suggest a method of bosonizing any D=2 theory. We demonstrate how it works with the examples of the Thirring and the Schwinger models, known results are reproduced. This method, being applied to the Gross-Neveu model, yields nonlinear boson WZW-type theory with additional constraint in the field space. Relation to the nonlinear sigma - model is also discu

J. C. R. Bloch, M. R. Pennington

The behaviour of the photon renormalization function in strong coupling QED has been recently studied by Kondo, Mino and Nakatani. We find that the sharp decrease in its behaviour at intermediate photon momenta is an artefact of the method used to remove the quadratic divergence in the vacuum polarization. We discuss how this can be avoided in numerical stud

Claudio Gheller, Lauro Moscardini, Ornella Pantano

We present the results of a series of one-dimensional N-body and hydrodynamical simulations which have been used for testing the different clustering properties of baryonic and dark matter in an expanding background. Initial Gaussian random density perturbations with a power-law spectrum $P(k) \propto k^n$ are assumed. We analyse the distribution of density

A. Hucht, A. Moschel, K. D. Usadel

We simulated the classical two-dimensional anisotropic Heisenberg model with full long range dipole interaction with an algorithm especially designed for long range models. The results show strong evidence for a first order reorientation transition at a temperature $T_R < T_C$ for appropriate parameters of the model Hamiltonian.

F. Schoeniger, Y. Sofue

A comparison between the CO and HI Tully-Fisher relation for a sample of 30 Virgo ga\-la\-xies shows no significant difference concerning the intrinsic scatter. The distance moduli from both relations after correcting for the sample incompleteness bias agree within the errors and also show no significant difference with previous studies of the Virgo cluster

A. O. Jaunsen, M. Jablonski, B. R. Pettersen, R. Stabell

A gravitational lens (GL)-search program, initiated in 1990 at the Nordic Optical Telescope (NOT), has revealed several possible GL-candidates among a sample of 168 quasars (QSOs), chosen from three lists compiled by C. Hazard, D. Reimers and J. Surdej, respectively. Some of these candidates, selected for having close companions (within 5 arcseconds), were i

V. A. Saleev, N. P. Zotov

Processes of hevy quark photoproduction at HERA energies and beyond are investigated using the semihard ($k_{\bot}$ factorization) approach. The virtuality and longitudinal polarization of gluons in the photon - gluon subprocess as well as the saturation effects in the gluon distribution function at small $x$ have been taken into account. The total cross sec

W. N. Brandt, K. A. Pounds, H. Fink

Zwicky 159.034, one of the Seyfert galaxies identified with EUV sources detected during the ROSAT Wide Field Camera (WFC) all-sky survey, has unusual properties. The ROSAT Position Sensitive Proportional Counter (PSPC) 0.1--2.5 keV X-ray spectrum, obtained simultaneously with the WFC survey, appears extremely steep. Subsequent deeper pointed observations wit

Kazuhiro Yamamoto, Misao Sasaki, Takahiro Tanaka

We consider an alternative scenario of inflation which can account for a spatially open universe. It is similar to the old inflation in which the bubble nucleation occurs in the sea of false vacuum, but differs from it in that the second slow rollover inflation occurs inside a nucleated bubble. Hence our observable universe is entirely contained in one nucle

Hafsa Khan, Pervez Hoodbhoy

We present a method which, starting directly from QCD, permits a systematic gauge-invariant expansion to be made for all hard processes involving quarkonia in powers of the quark relative velocity, a small natural parameter for heavy quark systems. Our treatment automatically introduces soft gluons in the expansion. Corrections arising from the incorporation

Yoshio Koide

Being inspired by a phenomenological success of a charged lepton mass formula, a model with U(3)-family nonet Higgs bosons is proposed. Here, the Higgs bosons $\phi_L$ ($\phi_R$) couple only between light fermions (quarks and leptons) $f_L$ ($f_R$) and super-heavy vector-like fermions $F_R$ ($F_L$), so that the model leads to a seesaw-type mass matrix $M_f\s

W. Kummer, W. Moedritsch

The bound state problem for a fermion-antifermion system is considered taking into account a finite decay width of the constituents. We propose an exactly solvable relativistic zero order equation similar to that of Barbieri and Remiddi, but including a constant width. We focus especially on the $t\bar{t}$ system for which we reconsider our recent calculatio

J. Hisano, T. Moroi, K. Tobe, M. Yamaguchi

We examine the lepton-flavor violation caused by a Yukawa coupling matrix $y_{\nu,ij}$ for right-handed neutrinos in the supersymmetric standard model. We stress that decay rates for $\tau\rightarrow\mu\gamma$ and $\mu\rightarrow e\gamma$ may reach the range to be accessible to near future experiments if left-right mixing terms in the slepton mass matrix are

Sebastian del Bano Rollin

We study the motive of the moduli spaces of semistable rank two vector bundles over an algebraic curve. When the degree is odd the moduli space is a smooth projective variety, we obtain the absolute Hodge motive of this, and in particular the Hodge-Poincare polynomial. When the degree is even the moduli space is a singular projective variety, we compute pure

S. R. Renn, D. P. Arovas

Non-linear current voltage characteristics of a disordered Luttinger liquid are calculated using a perturbative formalism. One finds non-universal power law characteristics of the form $I(V)\sim V^{1/(2\tilde{g}-1)}$ which is valid both in the superfluid phase when $I$ is small and also in the insulator phase when $I$ is large. Mesoscopic voltage fluctuation

Ross H. McKenzie

A model is presented for the destruction of density-wave states in quasi-one-dimensional crystals by high magnetic fields. The model is consistent with previously unexplained properties of the organic conductors (TMTSF)$_2$ClO$_4$ and (BEDT-TTF)$_2$MHg(SCN)$_4$ (M=K,Rb,Tl). As the magnetic field increases quasi-one-dimensional density-wave fluctuations incre

Takeo Kojima, Kei Miki, Yas-Hiro Quano

We consider the recently obtained integral representation of quantum Knizhnik-Zamolodchikov equation of level 0. We obtain the condition for the integral kernel such that these solutions satisfy three axioms for form factor \'{a} la Smirnov. We discuss the relation between this integral representation and the form factor of XXZ spin chain.

B. Reznik

The interaction of an open system $\s$ with a pre- and post-selected environment is studied. In general, under such circumstances $\s$ can not be described in terms of a density matrix, {\it even when $\s$ in not post-selected}. However, a simple description in terms of a two-state (TS) is always available. The two-state of $\s$ evolves in time from an initi

M. Hedayati-Poor, J. I. Johansson, H. S. Sherif

Non-relativistic reduction of the S-matrix for the quasifree electron scattering process $A\left(~e, e'p~\right)A-1$ is studied in order to understand the source of differences between non-relativistic and relativistic models. We perform an effective Pauli reduction on the relativistic expression for the S-matrix in the one-photon exchange approximation. The

Sandra S. Padula, Miklos Gyulassy

A $\chi^2$ analysis is performed to test the resolving power of two-dimensional pion interferometry using for illustration the preliminary E802 data on $Si+Au$ at 14.6 AGeV/c. We find that the resolving power to distinguish two decoupling geometries of different dynamical models is enhanced by studying the variation of the mean $\chi^2$ per degrees of freedo

T. J. Davidge, M. Grinder

Slit spectra, covering the rest frame near-ultraviolet and blue wavelength regions, are combined with moderately deep g and R images to investigate radial population gradients in the brightest components of six z=0.2 galaxy clusters selected by x-ray brightness. We conclude that the brightest cluster galaxies (BCGs) of the EMSS0440+02, EMSS0906+11 and EMSS12

Sen-Ben Liao, Michael Strickland

Scalar field theory at finite temperature is investigated via an improved renormalization group prescription which provides an effective resummation over all possible non-overlapping higher loop graphs. Explicit analyses for the lambda phi^4 theory are performed in d=4 Euclidean space for both low and high temperature limits. We generate a set of coupled equ

G. M. Gandenberger

Using Hollowood's conjecture for the S-matrix for elementary solitons in complex $a_n^{(1)}$ affine Toda field theories we examine the interactions of bound states of solitons in $a_2^{(1)}$ theory. The elementary solitons can form two different kinds of bound states: scalar bound states (the so-called breathers), and excited solitons, which are bound states

N. Lehmann, D. V. Savin, V. V. Sokolov, H. -J. Sommers

We study the correlations of time delays in a model of chaotic resonance scattering based on the random matrix approach. Analytical formulae which are valid for arbitrary number of open channels and arbitrary coupling strength between resonances and channels are obtained by the supersymmetry method. We demonstrate that the time delay correlation function, th

T. Barnes, F. E. Close, E. S. Swanson

We present results from analytical and numerical studies of a flux tube model of hybrid mesons. Our numerical results use a Hamiltonian Monte Carlo algorithm and so improve on previous analytical treatments, which assumed small flux tube oscillations and an adiabatic separation of quark and flux tube motion. We find that the small oscillation approximation i

Ivan K. Kostov

We construct a string field Hamiltonian describing the dynamics of open and closed strings with effective target-space dimension $c\le 1 $. In order to do so, we first derive the Dyson-Schwinger equations for the underlying large $N$ vector+matrix model and formulate them as a set of constraints satisfying decoupled Virasoro and U(1) current algebras. The Ha

S. Dittmaier, M. Kuroda, D. Schildknecht

We refine our recent analysis of the electroweak precision data at the \PZO\ pole by including the hadronic decay modes of the \PZO. Within the framework of an effective Lagrangian we parametrize $SU(2)$ violation by the additional process-specific parameters $\De y_\nu$, $\De\yh$, and $\De\yb$ (for the $\PZO\nu\bar\nu$, $\PZO\Pq\bar\Pq$, and $\PZO\Pb\bar\Pb

Lawrence A. Harris

We define the domain of a linear fractional transformation in a space of operators and show that both the affine automorphisms and the compositions of symmetries act transitively on these domains. Further, we show that Liouville's theorem holds for domains of linear fractional transformations, and, with an additional trace class condition, so does the Rieman

E. Alfinito, M. Leo, R. A. Leo, M. Palese

We apply the (direct and inverse) prolongation method to a couple of nonlinear Schr{\"o}dinger equations. These are taken as a laboratory field model for analyzing the existence of a connection between the integrability property and loop algebras. Exploiting a realization of the Kac-Moody type of the incomplete prolongation algebra associated with the system

Manu Mathur

We compute the effective action in terms of the Polyakov loop for the 3-dimensional pure fundamental-adjoint SU(2) lattice gauge theory at non-zero temperatures using the strong coupling expansion. In the extended coupling plane we show the existence of a tricritical point where the nature of the deconfinement transition undergoes a change from second to fir

B. L. Altshuler, L. B. Ioffe, A. I. Larkin, A. J. Millis

Strongly correlated two dimensional electrons are believed to form a spin liquid in some regimes of density and temperature. As the density is varied, one expects a transition from this spin liquid state to a spin density wave antiferromagnetic state. In this paper we show that it is self-consistent to assume that this transition is second order and, on this

U . Bernert, K. Koepernik

A method is established which allows the calculation of the walk dimension for Sierpinski-type multifractals. The multifractal scaling behaviour of the average time needed to cover a distance in the mentionned multifractals is shown. For the average-time-multifractal we calculate the Renyi dimensions and allpy the f(alpha)-formalism.

Stephan Narison

We test the internal consistencies and the reliability of the existing estimates of the decay constant $f_B$ in the static limit, the meson-quark mass gap $\bar \Lambda$ and the kinetic energy $K$ of a heavy quark obtained from the heavy quark effective theory (HQET)-sum rules. Finite energy local duality sum rules (FESR) have also been used to fix $approxim

Mannque Rho

I discuss recent work done with Gerry Brown on chiral phase transition at high temperature and/or density described in terms of Georgi's vector limit. The notion of ``mended symmetry" is suggested to play an important role in understanding the properties of hadrons in dense and/or hot matter before reaching the phase transition. It is shown that while the QC

J. A. Eden, M. F. Gari

The long-standing discrepancy between pp-bremsstrahlung data and calculations based on the relativistic impulse approximation current is substantially reduced by the inclusion of the PV$\gamma$ and intermediate-state $\Delta$-resonance iso-scalar meson-exchange currents. The success of the standard procedures adopted here shows that pp-bremsstrahlung provide

E. Agirre, X. Arregi, X. Artola, A. Diaz de Ilarraza

The frame-based knowledge representation model adopted in IDHS (Intelligent Dictionary Help System) is described in this paper. It is used to represent the lexical knowledge acquired automatically from a conventional dictionary. Moreover, the enrichment processes that have been performed on the Dictionary Knowledge Base and the dynamic exploitation of this k

K. J. Abraham, Frank Cuypers, Geert Jan van Oldenborgh

We study the possibility that the production and decay of light stop squarks at Tevatron can mimic top events. We show that this scenario is very unlikely to explain the anomalously high top production cross sections recently reported by the CDF collaboration.

Alexander Reznikov

We attack a conjecture of J. Rogawski: any cocompact lattice in $S U (2, 1)$ for which the ball quotient $X = B^2 / \Gamma$ satisfies $b_1 (X) = 0$ and $H^{1, 1} (X) \cap H^2 (X, \bbq) \approx \bbq$ is arithmetic. We prove the Archimedian suprerigidity for representation of $\Gamma$ is $S L (3, \bbc)$.

S. O. Warnaar

The problem of computing the one-dimensional configuration sums of the ABF model in regime III is mapped onto the problem of evaluating the grand-canonical partition function of a gas of charged particles obeying certain fermionic exclusion rules. We thus obtain a new {\em fermionic} method to compute the local height probabilities of the model. Combined wit

G. Kälbermann, J. M. Eisenberg

Within the skyrmion approach for the nucleon-nucleon force, difficulties have been experienced in obtaining an isoscalar attractive spin-orbit potential, in parallel to the problems of finding attraction in the isoscalar central potential. We here study the spin-orbit force using a skyrmion with four- and six-derivative stabilizing terms in the lagrangian as

Osamu ABE

The behavior of small perturbations around the Kaluza-Klein monopole in the five dimensional space-time is investigated. The fact that the odd parity gravitational wave does not propagate in the five dimensional space-time with Kaluza-Klein monopole is found provided that the gravitational wave is constant in the fifth direction.

John F. McGowan

In this paper, several calculations of the matrix elements for processes that may contribute to e+ e- --> pi+ pi- pi0 pi0 using the isobar model and the Lorentz invariant amplitude method are presented. The formulas may be used to determine the electromagnetic form factors of the rho meson if e+ e- --> rho+ rho- contributes to e+ e- --> pi+ pi- pi0 pi0 The e

Hans J. Haubold

Physical principles and mathematical structure involved in deriving an analytical representation of the internal structure of the Sun is discussed. For a two-parameter family of a non-linear matter density distribution, the run of mass, pressure, temperature, and luminosity throughout the Sun is presented in terms of Gauss' hypergeometric function. The syste

K Lipman, M Pettini, R Hunstead

Our knowledge of galactic chemical evolution is currently limited to observations of Milky Way stars and H II regions of nearby galaxies. Damped Lyman~$α$ systems offer a new approach for tracking the evolution of normal galaxies from early epochs to the present day. Here we report the first measurements of nitrogen abundances in galaxies with less than 1/10

Andrew Gould

Intra-Cluster Machos (ICMs) are a plausible candidate for at least some of the dark matter in clusters of galaxies. ICMs can be detected by searching toward M87 for ``pixel lensing'', gravitational microlensing of unresolved stars. Dedicated observations by the Wide Field and Planetary Camera on the {\it Hubble Space Telescope} would discover lenses at a rat

L. V. Bogdanov

Hirota bilinear identity for Cauchy-Baker-Akhieser (CBA) kernel is introduced as a basic tool to construct integrable hierarchies containing lattice and q-difference times. Determinant formula for the action of meromorphic function on CBA kernel is derived. This formula gives opportunity to construct generic solutions for integrable lattice equations.

Minos Axenides, Andrei Johansen, Jesper Moller

We argue for the presence of a ${\bf Z}_2$ topological structure in the space of static gauge-Higgs field configurations of $SU(2n)$ and $SO(2n)$ Yang-Mills theories. We rigorously prove the existence of a ${\bf Z}_2$ homotopy group of mappings from the 2-dim. projective sphere ${\bf R}P^2$ into $SU(2n)/{\bf Z}_2$ and $SO(2n)/{\bf Z}_2$ Lie groups respective

Shamit Kachru

It has recently been realized that a large class of Calabi-Yau models in which the VEV of the gauge connection is not set equal to the spin connection of the Calabi-Yau manifold are valid classical solutions of string theory. We provide some examples of three generation models based on such generalized Calabi-Yau compactifications, including models with obse

E. Arrigoni, G. C. Strinati

The Hubbard model with finite on-site repulsion U is studied via the functional-integral formulation of the four-slave-boson approach by Kotliar and Ruckenstein. It is shown that a correct treatment of the continuum imaginary time limit (which is required by the very definition of the functional integral) modifies the free energy when fluctuation (1/N) corre

Pierre Le Doussal, Valerii M. Vinokur

The dynamics of a glass transition is discussed in terms of the motion of a particle in a one dimensional correlated random potential. An exact calculation of the velocity $V$ under an applied force $f$ demonstrates a variety of dynamic regimes depending on the range of correlations. In a gaussian potential with correlator $C(x) = x^{\gamma}$, we find a tran

Jakub Zakrzewski, Karine Dupret, Dominique Delande

For systems whose classical dynamics is chaotic, it is generally believed that the local statistical properties of the quantum energy levels are well described by Random Matrix Theory. We present here two counterexamples - the hydrogen atom in a magnetic field and the quartic oscillator - which display nearest neighbor statistics strongly different from the

Michael Engelhardt

When addressing the thermodynamics of finite-sized systems, one must specify whether one wants to fix conserved charges to a sharp value or whether one is content to fix their thermodynamic average. In other words, contrary to the thermodynamic limit, different statistical ensembles are not equivalent. When treating the plasma phases of gauge field theories

N. K. Devine, S. J. Wallace

A quasipotential formalism for elastic scattering from relativistic bound states is based on applying an instant constraint to both initial and final states in the Breit frame. This formalism is advantageous for the analysis of electromagnetic interactions because current conservation and four momentum conservation are realized within a three-dimensional for

L. S. Levitov, A. V. Shytov

Effective action is proposed for the problem of Coulomb blocking of tunneling. The approach is well suited to deal with the ``strong coupling'' situation near zero bias, where perturbation theory diverges. By a semiclassical treatment, we reduce the physics to that of electrodynamics in imaginary time, and express the anomaly through exact conductivity of th

Dipak Munshi, Tarun Souradeep, Alexei A. Starobinsky

Skewness of temperature fluctuations of the cosmic microwave background (CMB) produced by initially Gaussian adiabatic perturbations with the flat (Harrison-Zeldovich) spectrum, which arises due to non-linear corrections to a gravitational potential at the matter-dominated stage, is calculated quantitatively. For the standard CDM model, the effect appears to

G. Gallavotti, E. G. D. Cohen

We propose as a generalization of an idea of Ruelle to describe turbulent fluid flow a chaotic hypothesis for reversible dissipative many particle systems in nonequilibrium stationary states in general. This implies an extension of the zeroth law of thermodynamics to non equilibrium states and it leads to the identification of a unique distribution $\m$ desc

L. V. Bogdanov, B. G. Konopelchenko

A general scheme is proposed for introduction of lattice and q-difference variables to integrable hierarchies in frame of $\bar{\partial}$-dressing method . Using this scheme, lattice and q-difference Darboux-Zakharov-Manakov systems of equations are derived. Darboux, B\"acklund and Combescure transformations and exact solutions for these systems are studied

B. H. Smith, X. P. Pan, D. H. Feng, M. Guidry

The global correlation in the observed variation with mass number of the $E2$ and summed $M1$ transition strengths is examined for rare earth nuclei. It is shown that a theory of correlated $S$ and $D$ fermion pairs with a simple pairing plus quadrupole interaction leads naturally to this universality. Thus a unified and quantitative description emerges for

Ulvi Yurtsever

The averaged null energy condition has been recently shown to hold for linear quantum fields in a large class of spacetimes. Nevertheless, it is easy to show by using a simple scaling argument that ANEC as stated cannot hold generically in curved four-dimensional spacetime, and this scaling argument has been widely interpreted as a death-blow for averaged en

P. B. Wiegmann, A. V. Zabrodin

A class of second order difference (discrete) operators with a partial algebraization of the spectrum is introduced. The eigenfuncions of the algebraized part of the spectrum are polinomials (discrete polinomials). Such difference operators can be constructed by means of $U_q(sl_2)$, the quantum deformation of the $sl_2$ algebra. The roots of polinomials det

Lawrence M. Krauss

Big Bang Nucleosynthesis represents perhaps the first, and still perhaps the most powerful particle-astrophysics connection. As such, it should provide an example for other work in this area. I discuss the current status of standard model BBN predictions and constraints, and then argue that the issue of observational systematic uncertainties is the key featu

M. Boyce, P. J. S. Watson

For over 50 years attempts have been made to explain the properties of nuclear matter in terms of constituent nucleons with very little success. Here we will investigate one class of many possible models, string-flip potential models, in which flux-tubes are connected between quarks (in a gas/plasma) to give a minimal overall field configuration. A general o

I. Guarneri, M. DiMeo

We numerically perform a spectral analysis of a quasi-periodically driven spin 1/2 system, the spectrum of which is Singular Continuous. We compute fractal dimensions of spectral measures and discuss their connections with the time behaviour of various dynamical quantities, such as the moments of the distribution of the wave packet. Our data suggest a close

M. Bucher, A. S. Goldhaber, N. Turok, .

An inflationary scenario that leads to $\Omega _0<1$ today is presented. An epoch of `old' inflation during which the smoothness and horizon problems are solved is followed by a shortened epoch of `new' inflation. Old inflation exits through the nucleation of a single bubble, leading to negative spatial curvature on slices of constant cosmic time. We calcula

E. J. M. Colbert, R. Petre, E. M. Schlegel, S. D. Ryder

The nearby barred spiral galaxy NGC 1313 has been observed with the PSPC instr- ument on board the ROSAT X-ray satellite. Ten individual sources are found. Three sources (X-1, X-2 and X-3 [SN~1978K]) are very bright (~10^40 erg/s) and are unusual in that analogous objects do not exist in our Galaxy. We present an X-ray image of NGC~1313 and \xray spectra for

András Kaiser, Alan Chodos

We study symmetry breaking in the static coordinate-system of de Sitter space. This is done with the help of the functional-Schr\"odinger approach used in previous calculations by Ratra [1]. We consider a massless, minimally coupled scalar field as the parameter of a continuous symmetry (the angular component of an O(2) symmetry). Then we study the correlati

A. Ballesteros, F. J. Herranz, M. A. del Olmo, C. M. Pereña

The Hopf algebra dual form for the non--standard uniparametric deformation of the (1+1) Poincar\'e algebra $iso(1,1)$ is deduced. In this framework, the quantum coordinates that generate $Fun_w(ISO(1,1))$ define an infinite dimensional Lie algebra. A change in the basis of the dual form is obtained in order to compare this deformation to the standard one. Fi

A. Ballesteros, E. Celeghini, F. J. Herranz, M. A. del Olmo

A universal quasitriangular $R$--matrix for the non-standard quantum (1+1) Poincar\'e algebra $U_ziso(1,1)$ is deduced by imposing analyticity in the deformation parameter $z$. A family $g_\mu$ of ``quantum graded contractions" of the algebra $U_ziso(1,1)\oplus U_{-z}iso(1,1)$ is obtained; this set of quantum algebras contains as Hopf subalgebras with two pr

Maarten Golterman, Yigal Shamir

Recently, Narayanan and Neuberger proposed that the fermion determinant for a lattice chiral gauge theory be defined by an overlap formula. The motivation for that formula comes from Kaplan's five dimensional lattice domain wall fermions. In the case that the target continuum theory contains $4n$ chiral families, we show that the effective action defined by

Jakub Zakrzewski

Numerical study of the parametric motion of energy levels in a model system built on Random Matrix Theory is presented. The correlation function of levels' slopes (the so called velocity correlation function) is determined numerically and compared with its limiting analytic form when available. A simple analytic form of the velocity correlation function is p

W. Kalthoff, S. Schwarzer, G. H. Ristow, H. J. Herrmann

We present a numerical method to deal efficiently with large numbers of particles in incompressible fluids. The interactions between particles and fluid are taken into account by a physically motivated ansatz based on locally defined drag forces. We demonstrate the validity of our approach by performing numerical simulations of sedimenting non-Brownian spher

D. V. Fursaev, S. N. Solodukhin

A consistent approach to the description of integral coordinate invariant functionals of the metric on manifolds ${\cal M}_{\alpha}$ with conical defects (or singularities) of the topology $C_{\alpha}\times\Sigma$ is developed. According to the proposed prescription ${\cal M}_{\alpha}$ are considered as limits of the converging sequences of smooth spaces. Th

Valentin Ferenczi

A {\em hereditarily indecomposable (or H.I.)} Banach space is an infinite dimensional Banach space such that no subspace can be written as the topological sum of two infinite dimensional subspaces. As an easy consequence, no such space can contain an unconditional basic sequence. This notion was first introduced in 1993 by T.Gowers and B.Maurey, who construc

Jose P. Mimoso, David Wands

We examine homogeneous but anisotropic cosmologies in scalar-tensor gravity theories, including Brans-Dicke gravity. We present a method for deriving solutions for any isotropic perfect fluid with a barotropic equation of state ($p\propto\rho$) in a spatially flat (Bianchi type~I) cosmology. These models approach an isotropic, general relativistic solution a

Debashis Ghoshal, Sudhakar Panda

The time evolution in a supersymmetric extension of the Kodomtsev-Petviashvilli hierarchy, a classical integrable system, is shown to be Hamiltonian. The canonical bracket associated to the Hamiltonian evolution is the classical analog of the antibracket encountered in the quantization of gauge theories. This provides a new understanding of supersymmetric Ha

A. Venugopalan, Deepak Kumar, R. Ghosh

According to Bell's theorem, the degree of correlation between spatially separated measurements on a quantum system is limited by certain inequalities if one assumes the condition of locality. Quantum mechanics predicts that this limit can be exceeded, making it nonlocal. We analyse the effect of an environment modelled by a fluctuating magnetic field on the