May 1996 arXiv papers — page 4

D. Maison

Subject of this talk is an overview of results on self-gravitating solitons of the classical Yang-Mills-Higgs theory. One finds essentially two classes of solitons, one of them corresponding to the magnetic monopoles the other one to the sphalerons of flat space. The coupling to the gravitational field leads to new features absent in flat space. These are th

M. Toller

A quantum frame is defined by a material object subject to the laws of quantum mechanics. The present paper studies the relations between quantum frames, which in the classical case are described by elements of the Poincare' group. The possibility of using a suitable quantum group is examined, but some arguments are given which show that a different math

Michael Basler, Wolfram Krech, Konstantin Yu. Platov

A recently proposed scheme for the analytical treatment of the dynamics of two-dimensional hybrid Josephson junction arrays is extended to a class of generalized hybrid arrays with ''horizontal'' shunts involving a capacitive as well as an inductive component. This class of arrays is of special interest, because the internal cell coupling has

M. Serva, G. Paladin

We study the d-dimensional random Ising model using a Bethe-Peierls approximation in the framework of the replica method. We take into account the correct interaction only inside replicated clusters of spins. Our ansatz is that the interaction of the borders of the clusters with the external world can be described via an effective interaction among replicas.

Simon C. Benjamin, Neil F. Johnson, P. M. Hui

We examine various realistic generalizations of the basic cellular automaton model describing traffic flow along a highway. In particular, we introduce a {\em slow-to-start} rule which simulates a possible delay before a car pulls away from being stationary. Having discussed the case of a bare highway, we then consider the presence of a junction. We study th

P. Pieri

We prove, as recently conjectured, that the ground state of the Hubbard Hamiltonian with an infinite-range hopping, when the number of electrons $N_e=N+1$ ($N$ being the number of sites), is ferromagnetic fully polarized.

V. I. Belinicher, A. L. Chernyshev, V. A. Shubin

A microscopically based Hamiltonian of the generalized $t$-$t^\prime$-$J$ model is presented. Two types of the additional $t^\prime$-terms are discussed. The set of ranges of the additional $t^\prime$-terms for the real CuO$_2$ planes is derived from the three-band model calculations. Using the variational spin-polaron approach the single-carrier dispersions

Rens Bod

This note is a reply to Joshua Goodman's paper "Efficient Algorithms for Parsing the DOP Model" (Goodman, 1996; cmp-lg/9604008). In his paper, Goodman makes a number of claims about (my work on) the Data-Oriented Parsing model (Bod, 1992-1996). This note shows that some of these claims must be mistaken.

Holger Bech Nielsen, Hans Henrik Rugh, Svend Erik Rugh

Without an ultraviolet cut-off, the time evolution of the classical Yang-Mills equations give rise to a never ending cascading of the modes towards the ultraviolet, and ergodic measures and dynamical averages, such as the spectrum of characteristic Lyapunov exponents (measures of temporal chaos) or spatial correlation functions, are ill defined. A lattice re

P. O. Fedichev, M. W. Reynolds, G. V. Shlyapnikov

We discuss three-body recombination of ultra-cold atoms to a weakly bound $s$ level. In this case, characterized by large and positive scattering length $a$ for pair interaction, we find a repulsive effective potential for three-body collisions, which strongly reduces the recombination probability and makes simple Jastrow-like approaches absolutely inadequat

P. O. Fedichev, Yu. Kagan, G. V. Shlyapnikov, J. T. M. Walraven

We develop the idea of manipulating the scattering length $a$ in low-temperature atomic gases by using nearly resonant light. As found, if the incident light is close to resonance with one of the bound $p$ levels of electronically excited molecule, then virtual radiative transitions of a pair of interacting atoms to this level can significantly change the va

Lev Kofman

In the inflationary scenario all the matter constituting the universe was created from the process of reheating after inflation. Recent development of the theory of reheating is briefly reviewed. The list of topics includes elementary (perturbative) theory of reheating; quantum field theory in a time-varying background; parametric resonance and explosive par

S. G. Djorgovski, M. A. Pahre, J. Bechtold, R. Elston

Galaxies believed to be responsible for damped Ly-alpha absorption (DLA) systems in the spectra of high-redshift quasars represent a viable population of progenitors of normal disk galaxies. They appear to contain a substantial fraction of the baryons known to exist in normal galaxies today. Here we report on the detection of an object, designated DLA 2233+1

B. Ricci

In connection with the recent suggestion by Tsytovich et al. that opacity in the solar core could be overestimated, we consider the following questions: i) What would a 10\% opacity reduction imply for the solar neutrino puzzle? ii) Is there any hope of solving the solar neutrino puzzle by changing opacity? iii) Is a 10\% opacity reduction testable with heli

D. Fargion

We consider the gravitational clustering of a multicomponent fluid in an expanding Newtonian universe, taking into account the mutual gravitational interactions of the medium. We obtain a set of exact and approximate solutions for two fluid components and for several fluid components: primordial hydrogen and helium or cosmological massive neutrinos of differ

E. Gourgoulhon, S. Bonazzola

Continuous wave gravitational radiation from isolated rotating neutron stars is discussed. The general waveform and orders of magnitude for the amplitude are presented for various known pulsars. The specific case of gravitational radiation resulting from the distortion induced by the stellar magnetic field is presented. Finally some preliminary results about

P. Haensel, S. Bonazzola

Possible consequences of ferromagnetic transition in dense matter suggested recently by Kutschera and W{ó}jcik, for the magnetic properties of neutron stars, are studied. Specific model of dense matter, in which a small admixture of protons is completely polarized due to their interaction with neutrons, is considered. Magnetic field of neutron stars with a f

J. A. Casas

We show that the usual dilaton dominance scenario, derived from the tree level Kähler potential, can never correspond to a global minimum of the potential at $V=0$. Similarly, it cannot correspond to a local minimum either, unless a really big conspiracy of different contributions to the superpotential $W(S)$ takes place. These results, plus the fact that th

R. Eder, P. Wrobel, Y. Ohta

We present an exact diagonalization study of the frequency and wave vector dependent conductivity $σ(q,ω)$ in small clusters of $2D$ $t$$-$$J$ model. Unlike the related dynamical density correlation function, $σ(q=0,ω)$ in the underdoped regime has the exchange constant $J$ as its characteristic energy scale and is dominated by a resonance-like excitation wi

Simon C. Benjamin, Neil F. Johnson, Luis Quiroga

We present an exact expression for the evolution of the wavefunction of $N$ interacting atoms in an arbitrarily time-dependent, $d$-dimensional parabolic trap potential $ω(t)$. The interaction potential between atoms is taken to be of the form $ξ/r^2$ with $ξ>0$. For a constant trap potential $ω(t)=ω_0$, we find an exact, infinite set of relative mode excita

Arthur Kosowsky, Marc Kamionkowski, Gerard Jungman, David N. Spergel

Recently funded satellites will map the cosmic microwave background radiation with unprecedented sensitivities and angular resolutions. Assuming only primordial adiabatic scalar and tensor perturbations, we evaluate how accurately experiments of this type will measure the basic cosmological parameters $\Omega$ (the total density of the Universe), $\Omega_b$

I. Borsari, M. Degli esposti, S. Graffi, F. Unguendoli

We consider the infinite-range deterministic spin models with Hamiltonian $H=\sum_{i,j=1}^N J_{i,j}σ_iσ_j$, where $J$ is the quantization of a chaotic map of the torus. The mean field (TAP) equations are derived by summing the high temperature expansion. They predict a glassy phase transition at the critical temperature $T\sim 0.8$.

Massimo Di Pierro, Kenichi Konishi

Several physics aspects of the Seiberg-Witten solution of N=2 supersymmetric Yang-Mills theory with SU(2) gauge group, supplemented with a small mass term for the "matter" fields which leads to an $N=1$ theory with confinement, are discussed. The light spectrum of the theory is understood on the basis of current algebra relations, and CP invariance o

H. Oberhummer, H. Herndl, R. Hofinger, Y. Yamamoto

The halo effect in the final states of astrophysically relevant direct neutron--capture reactions by neutron--rich nuclei is discussed. As an example, we calculate the cross sections for $^{18}$O(n,$\gamma$)$^{19}$O at thermonuclear and thermal energies.

Tomohiro Matsuda

We examine the mechanism of gaugino condensation in supersymmetric theories within a Nambu-Jona-Lasinio type approach. We investigate the effective Lagrangian description of higher energy theories that include some moduli fields in the gauge coupling constant. First we consider supersymmetric QCD with and without a mass term. We can find a phase transition i

E. J. Chun, A. Lukas

In the simplest model of horizontal U(1) symmetry with one singlet added to the supersymmetric standard model, we systematically reconstruct quark mass matrices from the low-energy data to prove that there are only two mass matrices found by Binetruy et.~al.. The same U(1) symmetry constrains the hierarchical structure of L-violating couplings, from which we

Richard Easther, Kei-ichi Maeda

We study the cosmological implications of the one-loop terms in the string expansion. In particular, we find non-singular solutions which interpolate between a contracting universe and an expanding universe, and show that these solutions provide a mechanism for removing the initial conditions problem peculiar to spatially closed FRW cosmologies. In addition,

Gilles Brassard

An explicit quantum circuit is given to implement quantum teleportation. This circuit makes teleportation straightforward to anyone who believes that quantum computation is a reasonable proposition. It could also be genuinely used inside a quantum computer if teleportation is needed to move quantum information around. An unusual feature of this circuit is th

Michel Boyer, Gilles Brassard, Peter Hoeyer, Alain Tapp

We provide a tight analysis of Grover's recent algorithm for quantum database searching. We give a simple closed-form formula for the probability of success after any given number of iterations of the algorithm. This allows us to determine the number of iterations necessary to achieve almost certainty of finding the answer. Furthermore, we analyse the be

H. Kleinert, S. Thoms

We present an approximative calculation of the ground-state energy for the anisotropic anharmonic oscillator Using an instanton solution of the isotropic action $δ= 0$, we obtain the imaginary part of the ground-state energy for small negative $g$ as a series expansion in the anisotropy parameter $δ$. From this, the large-order behavior of the $g$-expansions

G. Q. Liu, A. W. Thomas, P. A. M. Guichon

We calculate the $N^*$ contributions to the generalized polarizabilities of the proton in virtual Compton scattering. The following nucleon excitations are included: $N^*(1535)$, $N^*(1650)$, $N^*(1520)$, $N^*(1700)$, $Δ(1232)$, $Δ^*(1620)$ and $Δ^*(1700)$. The relationship between nucleon structure parameters, $N^*$ properties and the generalized polarizabi

Marcelo R. Ubriaco

We calculate the partition function, average occupation number and internal energy for a $SU_q(2)$ fermionic system and compare this model at $T=0$ with the ordinary fermionic, $q=1$, case. At low temperatures and $q\gg 1$ we find the chemical potential $μ$ to have the same temperature dependence than the Fermi case. For $q\ll 1$, the function $μ(T)$ has in

K. Arthur

The purpose of this Letter is to present a computation of the interaction energy of gauged O(3) Chern-Simons vortices which are infinitely separated. The results will show the behaviour of the interaction energy as a function of the constant coupling the potential, which measures the relative strength of the matter self-coupling and the electromagnetic coupl

Soo-Jong Rey

Classical string cosmology consists of two branches related to each other by scale-factor duality: a super-inflation branch and a Friedmann-Robertson-Walker (FRW) branch. Curvature and string coupling singularity separates the two branches, hence posing `graceful exit problem' to super-inflationary string cosmology. In an exactly soluble two-dimensional

Masato Hisakado, Miki Wadati

Recursion relations for orthogonal polynominals, arising in the study of the one-matrix model of two-dimensional gravity, are shown to be equvalent to the equations of the Toda-chain hierarchy supplemented by additional Virasoro constraints. This is the case without the double scaling limit. A discrete time variable to the matrix model is introduced. The dis

Vijay Balasubramanian, Igor Klebanov

We study the internal dynamics of Ramond-Ramond solitons excited far from the BPS limit by leading Regge trajectory open strings. The simplest world volume process for such strings is splitting into two smaller pieces, and we calculate the corresponding decay rates. Compared to the conventional open superstring, the splitting of states polarized parallel to

G. Semenoff, O. Tirkkonen, K. Zarembo

The problem of computing the thermodynamic properties of a one-dimensional gas of particles which transform in the adjoint representation of the gauge group and interact through non-Abelian electric fields is formulated and solved in the large $N$ limit. The explicit solution exhibits a first order confinement-deconfinement phase transition with computable p

Joannis Papavassiliou, Apostolos Pilaftsis

The consistent description of unstable particles, renormalons, or other Schwinger--Dyson-type of solutions within the framework of perturbative gauge field theories necessitates the definition and resummation of off-shell Green's functions, which must respect several crucial physical requirements. A formalism is presented for resummation of off-shell two

R. Peschanski

Models of intermittent behaviour are usually formulated using a set of multiplicative random weights on a Cayley tree. However, intermittency in particle multiproduction from QCD jets is related to fragmentation of an additive quantum number, e.g. energy-momentum. We exhibit the non-trivial stochastic mapping between these {\it additive} and {\it multiplicat

P V Landshoff

The soft pomeron successfully correlates a wide variety of data. Its properties seem rather simple: it couples to single quarks and its coupling factorises.

R. Brandenberger, B. Carter, A. -C. Davis, M. Trodden

We investigate the cosmological consequences of particle physics theories that admit stable loops of superconducting cosmic string - {\it vortons}. General symmetry breaking schemes are considered, in which strings are formed at one energy scale and subsequently become superconducting in a secondary phase transition at what may be a considerably lower energy

Ian J. R. Aitchison, Georges Ripka

We show that the procedure of regularizing the real part of the euclidean action, while leaving the imaginary part unregularized, leads to a non-analytic and highly singular functional of the fields. It is customary to work with an imaginary time component of the vector field, in order to avoid regularization of the anomalous processes. We show that this pro

S. V. Chekanov, W. Kittel, V. I. Kuvshinov

A new method for the experimental study of bin-bin correlations is proposed. It is shown that this method is able to reveal important additional information on bin-bin correlations, beyond that of factorial-correlator measurements.

S. V. Chekanov, V. I. Kuvshinov

We introduce the parameter of bunching for an analysis of the intermittent structure of multihadron production in high-energy collisions following an analogy with photon counting in quantum optics. A power-law singularity is shown to exist for second-order bunching parameters in small phase-space intervals for the case of a monofractal structure of the multi

Rajan Gupta, Tanmoy Bhattacharya, Gregory Kilcup

This talk presents results of a comparitive study of iterative algorithms like minimal residue ($MR$) and conjugate gradient ($CG$, $BiCGγ_5$, and \bicgstab) used for inverting the Dirac matrix $M$. The tests were done on the Connection Machine CM-5 using $32^3 \times 64$ lattices. The fermion action used is of Wilson type, both with and without the clover t

Claude Bernard, Tom Blum, Carleton DeTar, Steven Gottlieb

We present results of an ongoing study of the nature of the high temperature crossover in QCD with two light fermion flavors. These results are obtained with the conventional staggered fermion action at the smallest lattice spacing to date---approximately 0.1 fm. Of particular interest are a study of the temperature of the crossover a determination of the in

ZEUS Collaboration

Jet photoproduction, where the two highest transverse energy ($\ETJ$) jets have $\ETJ$ above 6 GeV and a jet-jet invariant mass above 23~GeV, has been studied with the ZEUS detector at the HERA $ep$ collider. Resolved and direct photoproduction samples have been separated. The cross section as a function of the angle between the jet-jet axis and the beam dir

Salvatore Capozziello, Ruggiero de Ritis

We give conditions to obtain cosmological asymptotic freedom in scalar-tensor theories of gravity. We show that this feature can be achieved in FRW flat spacetimes since we obtain singularity free solutions where the effective gravitational constant $G_{eff}\rightarrow 0$ for $t\rightarrow -\infty$ and, for some of them, $G_{eff}\rightarrow G_{N}$ for $t\rig

Kun Yang, K. Moon, Lotfi Belkhir, H. Mori

At strong magnetic fields double-layer two-dimensional-electron-gas systems can form an unusual broken symmetry state with spontaneous inter-layer phase coherence. The system can be mapped to an equivalent system of pseudospin $1/2$ particles with pseudospin-dependent interactions and easy-plane magnetic order. In this paper we discuss how the presence of a

G. Gonzalez de la Cruz, Yu. G. Gurevich

The electron and phonon temperature distribution function are calculated in semiconductors. We solved the coupled one-dimensional heat-diffussion equations in the linear approximation in which the physical parameters on the sample are independent of the temperature. We also consider the heat flux at the surface of the semiconductor as a boundary condition fo

M. Itakura

The three-state Potts model with antiferromagnetic nearest-neighbor (n.n.) and ferromagnetic next-nearest-neighbor (n.n.n) interaction is investigated within a mean-field theory. We find that the phase-diagram contains two kind of ordered phases, so-called BSS phase and PSS phase, separated by a discontinuous phase transition line. Order-disorder transition

Hiroaki Ikeda, Kazumasa Miyake

It is shown on the basis of the Fermi liquid theory that the s-wave scattering potential due to nonmagnetic impurity is strongly enhanced by the mass enhancement factor $1/z$. As a result the impurity potential with moderate strength, of the order of the bandwidth of conduction electrons, gives scattering in the unitarity limit in strongly correlated metals

Kurt Stokbro, Stefano Baroni

We report on a computational study of the clean and oxygen-covered Rh(110) surface, based on density-functional theory within the local-density approximation. We have used plane-wave basis sets and Vanderbilt ultra-soft pseudopotentials. For the clean surface, we present results for the equilibrium structure, surface energy, and surface stress of the unrecon

Chetan Nayak, Frank Wilczek

By explicitly identifying a basis valid for any number of electrons, we demonstrate that simple multi-quasihole wavefunctions for the $ν=1/2$ Pfaffian paired Hall state exhibit an exponential degeneracy at fixed positions. Indeed, we conjecture that for $2n$ quasiholes the states realize a spinor representation of an expanded (continuous) nonabelian statisti

Tie-Zheng Qian, Ya-Sha Yi, Zhao-Bin Su

Applying the non-adiabatic Aharonov-Anandan phase approach to a mesoscopic ring with non-interacting many electrons in the presence of the spin-orbit interaction, Zeeman coupling and magnetic flux, we show that the time-reversal symmetry breaking due to Zeeman coupling is intrinsically different from that due to magnetic flux. We find that the direction of t

G. Chen, C. Kharif, S. Zaleski, J. Li

Numerical simulations describing plunging breakers including the splash-up phenomenon are presented. The motion is governed by the classical, incompressible, two-dimensional Navier-Stokes equation. The numerical modelling of this two-phase flow is based on a piecewise linear version of the volume of fluid method. Preliminary results concerning the time evolu

Gregory Eyink, Jack Xin

We establish by exact, nonperturbative methods a universality for the correlation functions in Kraichnan's ``rapid-change'' model of a passively advected scalar field. We show that the solutions for separated points in the convective range of scales are unique and independent of the particular mechanism of the scalar dissipation. Any non-universa

C. Alcock, R. A. Allsman, D. R. Alves, T. S. Axelrod

We report the discovery of 30 type a,b RR Lyrae (RRab) which are likely members of the Sagittarius (Sgr) dwarf galaxy. Accurate positions, periods, amplitudes and magnitudes are presented. Their distances are determined with respect to RRab in the Galactic bulge found also in the MACHO 1993 data. For R$_{\odot} = 8$ kpc, the mean distance to these stars is $

Martin Pohl

We discuss the radio {\it arc} at the galactic center to be the counterpart of the high-energy \gr source 2EG J1746-2852. The observed \gr flux is constant within the statistical limits and the spectrum is very hard. The lack of variability makes it highly unlikely that any of the compact sources in the vicinity of the Galactic Center is the counterpart of 2

R. G. Abraham, T. A. Smecker-Hane, J. B. Hutchings, R. G. Carlberg

The galaxy population in the intermediate-redshift ($z=0.228$) rich cluster Abell 2390 is investigated. We present velocities, colors, and morphological information for an exceptionally large sample of 323 galaxies (216 cluster members) in a 46$^\prime \times 7^\prime$ (6 $h^{-1}$ Mpc $\times$ 1 $h^{-1}$ Mpc) strip centered on the cD galaxy. This sample of c

G. Bono, R. Incerpi, M. Marconi

The effects of heavy elements abundance on theoretical observables is studied for both fundamental and first overtone RR Lyrae pulsators at fixed mass and luminosity level. Nonlinear models have been computed adopting three different metal content. It has been found that the bolometric amplitude of first overtone pulsators decreases as metallicity increases,

M. A. Lim, A. C. Clapp, M. J. Devlin, N. Figueiredo

During the fifth flight of the Microwave Anisotropy Experiment (MAX5), we revisited a region with significant dust emission near the star Mu Pegasi. A 3.5 cm$^{-1}$ low frequency channel has been added since the previous measurement (\cite{mei93a}). The data in each channel clearly show structure correlated with IRAS 100 \micron\ dust emission. The spectrum

Z. Arzoumanian, K. Joshi, F. A. Rasio, S. E. Thorsett

Previous timing data for PSR~B1620$-$26 were consistent with a second companion mass $m_2$ anywhere in the range $\sim10^{-3}-1\,M_\odot$, i.e., from a Jupiter-type planet to a star. We present the latest timing parameters for the system, including a significant change in the projected semi-major axis of the inner binary, a marginal detection of the fourth t

Marco Andreatta, Jarosław A. Wiśniewski

Let $\f: X \ra Z$ be a proper surjective map from a smooth complex manifold $X$ onto a normal variety $Z$. If $\f$ has connected fibers and $-K_X$ is $\f$-ample then $\f$ is called a good contraction. In the present paper we study good contractions, fibers of which have dimension less or equal than two: after describing possible two dimensional isolated fibe

Satya Mandal

Throughout this abstruct $A$ will denote a noetherian commutative ring of dimension $n$. The paper has two parts. Among the interesting results in Part-1 are the following: 1) {\it suppose that $f_1, f_2, ..., f_r$ (with $r \leq n$) is a regular sequence in $A$ and suppose $Q$ is a projective $A$-module of rank $r$ that maps onto the ideal $(f_1, f_2, ..., f

J. Gamboa, V. O. Rivelles, J. Zanelli

We consider the analog in one spatial dimension of the Bose-Fermi transmutation for planar systems. A quantum mechanical system of a spin 1/2 particle coupled to an abelian gauge field, which is classically invariant under gauge transformations and charge conjugation is studied. It is found that unless the flux enclosed by the particle orbits is quantized, a

Rafael D. Sorkin, Sumati Surya

It is well known that the inequivalent unitary irreducible representations (UIR's) of the mapping class group $G$ of a 3-manifold give rise to ``theta sectors'' in theories of quantum gravity with fixed spatial topology. In this paper, we study several families of UIR's of $G$ and attempt to understand the physical implications of the resulting quantum secto

Sean M. Carroll, Miguel E. Ortiz, Washington Taylor

The bulk and boundary magnetizations are calculated for the critical Ising model on a randomly triangulated disk in the presence of a boundary magnetic field h. In the continuum limit this model corresponds to a c = 1/2 conformal field theory coupled to 2D quantum gravity, with a boundary term breaking conformal invariance. It is found that as h increases, t

David P. DiVincenzo, Peter W. Shor

We exhibit a simple, systematic procedure for detecting and correcting errors using any of the recently reported quantum error-correcting codes. The procedure is shown explicitly for a code in which one qubit is mapped into five. The quantum networks obtained are fault tolerant, that is, they can function successfully even if errors occur during the error co

Yuri B. Suris

New integrable lattice systems are introduced, their different integrable discretization are obtained. Bäcklund transformations between these new systems and the relativistic Toda lattice (in the both continuous and discrete time formulations) are established.

M. J. Bowick, S. M. Catterall, G. Thorleifsson

We introduce and investigate numerically a minimal class of dynamical triangulations of two-dimensional gravity on the sphere in which only vertices of order five, six or seven are permitted. We show firstly that this restriction of the local coordination number, or equivalently intrinsic scalar curvature, leaves intact the fractal structure characteristic o

Guinevere Kauffmann, Stephane Charlot, Simon D. M. White

The standard picture holds that giant elliptical galaxies formed in a single burst at high redshift. Aging of their stellar populations subsequently caused them to fade and become redder. The Canada-France Redshift Survey provides a sample of about 125 galaxies with the luminosities and colours of passively evolving giant ellipticals and with 0.1 < z < 1. Th

Gerard van der Geer

In this paper a number of results on cycles on the moduli space of principally polarized abelian varieties is presented. Results include a determination of the tautological ring, bounds on the order of torsion of the top Chern class $λ_g$ and a determination of the cycle classes of the Ekedahl-Oort stratification in characteristic $p$. It includes as special

Ph. Jacquod, D. L. Shepelyansky, O. P. Sushkov

For two interacting particles (TIP) in one-dimensional random potential the dependence of the Breit-Wigner width $\Gamma$, the local density of states and the TIP localization length on system parameters is determined analytically. The theoretical predictions for $\Gamma$ are confirmed by numerical simulations.

F. Sylos Labini, A. Gabrielli, M. Montuori, L. Pietronero

We introduce and study two new concepts which are essential for the quantitative analysis of the statistical quality of the available galaxy samples. These are the dilution effect and the small scale fluctuations. We show that the various data that are considered as pointing to a homogenous distribution are all affected by these spurious effects and their in

Gilles Poirot

We introduce a matrix-operator formulation of the Anderson model in d=2. In a single slice, we can then derive an analogy between our model and a standard random matrices problem. This enables us to construct and control the Green function in one slice, which is an important prerequisite to a full multi-scale study of the problem using the Renormalisation Gr

S. M. Hayden, G. Aeppli, T. G. Perring, H. A. Mook

Pulsed neutron spectroscopy is used to make absolute measurements of the dynamic magnetic susceptibility of insulating YBa2Cu3O6.15. Acoustic and optical modes, derived from in- and out-of-phase oscillation of spins in adjacent CuO2 planes, dominate the spectra and are observed up to 250 meV. The optical modes appear first at 74 meV. Linear-spin-wave theory

Maximo Banados, Luis J. Garay, Marc Henneaux

Higher dimensional Chern-Simons theories, even though constructed along the same topological pattern as in 2+1 dimensions, have been shown recently to have generically a non-vanishing number of degrees of freedom. In this paper, we carry out the complete Dirac Hamiltonian analysis (separation of first and second class constraints and calculation of the Dirac

Francois Delduc, Nicola Maggiore, Olivier Piguet, Sylvain Wolf

The cohomology of the BRS operator corresponding to a group of rigid symmetries is studied in a space of local field functionals subjected to a condition of gauge invariance. We propose a procedure based on a filtration operator counting the degree in the infinitesimal parameters of the rigid symmetry transformations. An application to Witten's topological Y

Serguei B. Isakov, Susanne Viefers

Starting from a field theoretical description of multicomponent anyons with mutual statistical interactions in the lowest Landau level, we construct a model of interacting chiral fields on the circle, with the energy spectrum characterized by a symmetric matrix $g_{αβ}$ with nonnegative entries. Being represented in a free form, the model provides a field th

Jonathan L. Rosner

When a heavy quark and the corresponding antiquark are separated by more than $1.4 - 1.5$ fm, it becomes energetically favorable for a light quark-antiquark pair to be produced, leading to fragmentation into a pair of flavored mesons. The relation of this critical quark separation to other dimensional constants of the strong interactions (such as the pion de

A. Goldhaber, R. Parwani, H. Singh

We extend recent discussions about the effect of nonzero temperature on the induced electric charge, due to CP violation, of a Dirac or an &#39;t Hooft-Polyakov monopole. In particular, we determine the fractional electric charge of a very small &#39;t Hooft-Polyakov monopole coupled to light fermions at nonzero temperature. If dyons with fractional electric

P. Berglund, S. Katz, A. Klemm, P. Mayr

We describe a new kind of transition between topologically distinct $N=2$ type II Calabi--Yau vacua through points with enhanced non-abelian gauge symmetries together with fundamental charged matter hypermultiplets. We connect the appearance of matter to the local geometry of the singularity and discuss the relation between the instanton numbers of the Calab

Ashoke Sen

By analyzing $F$-theory on $K3$ near the orbifold limit of $K3$ we establish the equivalence between $F$-theory on $K3$ and an orientifold of type IIB on $T^2$, which in turn, is related by a T-duality transformation to type I theory on $T^2$. By analyzing the $F$-theory background away from the orbifold limit, we show that non-perturbative effects in the or

J. D. Cohn

The interior of a vacuum bubble in de Sitter space may give an open universe with sufficient homogeneity to agree with observations. Here, previous work by Bucher, Goldhaber and Turok is extended to describe a thin bubble wall with nonzero radius and energy difference across the wall. The vacuum modes present before formation of the bubble propagate into the

H. J. S. Dorren, R. K. Snieder

In this paper the stability of the Korteweg-de Vries (KdV) equation is investigated. It is shown analytically and numerically that small perturbations of solutions of the KdV-equation introduce effects of dispersion, hence the perturbation propagates with a different velocity then the unperturbed solution. This effect is investigated analytically by formulat

Michael Martin Nieto

Using Baker-Campbell-Hausdorff relations, the squeeze and harmonic-oscillator time-displacement operators are given in the form $\exp[δI] \exp[α(x^2)]\exp[β(x\partial)] \exp[γ(\partial)^2]$, where $α$, $β$, $γ$, and $δ$ are explicitly determined. Applications are discussed.

Ken&#39;ichi Kuga

We show monistic realism consistent with quantum theory may be restored by extending the essential idea of relativity in such a way that every physical system is eligible, in principle, for an observing system. As a result, a common logical basis of quantum theory and relativity, and hence that of modern quantum gauge theories emerges. Supported by this logi

Weiping Li

A. Casson defined an intersection number invariant which can be roughly thought of as the number of conjugacy classes of irreducible representations of $π_1(Y)$ into $SU(2)$ counted with signs, where $Y$ is an oriented integral homology 3-sphere. X.S. Lin defined an similar invariant (signature of a knot) to a braid representative of a knot in $S^3$. In this

Volodymyr V. Lyubashenko

Given an abelian k-linear rigid monoidal category V, where k is a perfect field, we define squared coalgebras as objects of cocompleted V tensor V (Deligne&#39;s tensor product of categories) equipped with the appropriate notion of comultiplication. Based on this, (squared) bialgebras and Hopf algebras are defined without use of braiding. If V is the categor

P. A. M. Guichon, G. Q. Liu, A. W. Thomas

Threshold photon electroproduction off the proton allows one to measure new electromagnetic observables which generalise the usual polarisabilities. There are -- a priori -- ten "generalised polarisabilities", functions of the virtual photon mass. The purpose of this paper is to lay down the appropriate formalism to extract these quantities from the photon e

Anthony C. Kable, Akihiko Yukie

The purpose of the paper is to prove an analogous correspondence for the above prehomogeneous vector space (1)-(3). For case (1) the correspondence is bijective. However, it turns out that the correspondence is not bijective for cases (2), (3). We describe the fiber structures of this correspondence in subsection 2-4. In section 1 we briefly review basic pro

Robert Myers

Given any connected, open 3-manifold $U$ having finitely many ends, a non-compact 3-manifold $M$ is constructed having the following properties: the interior of $M$ is homeomorphic to $U$; the boundary of $M$ is the disjoint union of finitely many planes; $M$ is not almost compact; $M$ is eventually end-irreducible; there are no proper, incompressible embedd

Caixing Gu, Dechao Zheng

In this paper we characterize when the semi-commutator $T_fT_g-T_{fg}$ of two Toeplitz operators $T_f$ and $T_g$ on the Hardy space of the bidisc is zero. We also show that there is no nonzero finite rank semi-commutator on the bidisc. Furthermore explicit examples of compact semi-commutators with symbols continuous on the bitorus $T^2$ are given.

Caixing Gu, Dechao Zheng

In this paper we characterize when the product of two block Toeplitz operators is a compact perturbation of a block Toeplitz operator on the Hardy space of the open unit disk. Necessary and sufficient conditions are given for the commutator of two block Toeplitz operators to be compact.

James Agler, Nicholas John Young

We introduce a natural class of functions, the {\em pseudomultipliers}, associated with a general Hilbert function space, prove an extension theorem which justifies the definition, give numerous examples and establish the nature of the 1-pseudomultipliers of Hilbert spaces of analytic functions under mild hypotheses.

Robert Myers

An end sum is a non-compact analogue of a connected sum. Suppose we are given two connected, oriented $n$-manifolds $M_1$ and $M_2$. Recall that to form their connected sum one chooses an $n$-ball in each $M_i$, removes its interior, and then glues together the two $S^{n-1}$ boundary components thus created by an orientation reversing homeomorphism. Now supp

Akihiko Yukie

This is part one of a series of papers. In this series of papers, we consider problems analogous to the Oppenheim conjecture from the viewpoint of prehomogeneous vector spaces.

Pierre Binétruy, Mary K. Gaillard, Yi-Yen Wu

We study gaugino condensation in the context of superstring effective theories using the linear multiplet formulation for the dilaton superfield. Including nonperturbative corrections to the Kähler potential for the dilaton may naturally achieve dilaton stabilization, with supersymmetry breaking and gaugino condensation; these three issues are interrelated i

David Berenstein, Richard Corrado, Willy Fischler, Sonia Paban

Using a formalism developed to include collective coordinates, we calculate the contributions to S-matrix elements due to off-shell D-branes in a string coupling expansion. The formalism is further used to establish a two-dimensional computation of higher order corrections to the D-brane tension, both for the bosonic and the supersymmetric cases.