April 1996 arXiv papers — page 11

Kedar Damle, T. Senthil, Satya N. Majumdar, Subir Sachdev

We consider a dilute Bose gas confined by a harmonic potential. We define an appropriate thermodynamic limit and analyze the properties of the phases and phase transition in this limit. Critical properties in the presence of the potential are found to be different from, though simply related, to those in the usual translationally invariant case. We argue tha

Julien Favand, Frédéric Mila

We propose an explanation of the mid-infrared peak observed in the optical conductivity of the Bechgaard salt (TMTSF)$_2$PF$_6$ in terms of electronic excitations. It is based on a numerical calculation of the conductivity of the quarter-filled, dimerized Hubbard model. The main result is that, even for intermediate values of $U/t$ for which the charge gap i

F. Becca, M. Tarquini, M. Grilli, C. Di Castro

We investigate the density instabilities present in the infinite-U Hubbard-Holstein model both at zero and finite momenta as well as the occurrence of Cooper instabilities with a specific emphasis on the role of long-range Coulomb forces. In carrying out this analysis a special attention is devoted to the effects of the strong local $e$-$e$ interaction on th

Sang-Yoon Kim

We study the critical behavior (CB) of all period $p$-tuplings $(p \!=\!2,3,4,\dots)$ in $N$ $(N \!=\! 2,3,4,\dots)$ symmetrically coupled one-dimensional maps. We first investigate the CB for the $N=2$ case of two coupled maps, using a renormalization method. Three (five) kinds of fixed points of the renormalization transformation and their relevant ``coupl

E. Bogomolny, O. Bohigas, P. Leboeuf

We investigate the distribution of roots of polynomials of high degree with random coefficients which, among others, appear naturally in the context of "quantum chaotic dynamics". It is shown that under quite general conditions their roots tend to concentrate near the unit circle in the complex plane. In order to further increase this tendency, we st

R. Silvotti

HS\,2324+3944 is a peculiar PG\,1159 star, with a high amount of H in its atmosphere (Dreizler et al. 1995). Its location in the $\log T_{\rm eff}$ -- $\log g$ plane is well inside the GW Vir instability strip. In this paper I report the results of two photoelectric observations of HS\,2324+39, which clearly show that the luminosity of this star presents per

Victor Barzykin, Ian Affleck

We analyse the role which the distance scale $ξ_K = v_F/T_K$ plays in the single-impurity Kondo problem using renormalization group improved perturbation theory. We derive the scaling functions for the local spin susceptibility in various limiting cases. In particular, we demonstrate exactly that the non-oscillating part of it should be short-range, i.e., va

Adrian Kent

In the consistent histories formulation of quantum theory, the probabilistic predictions and retrodictions made from observed data depend on the choice of a consistent set. We show that this freedom allows the formalism to retrodict contrary propositions which correspond to orthogonal commuting projections and which each have probability one. We also show th

David A. Meyer

A natural architecture for nanoscale quantum computation is that of a quantum cellular automaton. Motivated by this observation, in this paper we begin an investigation of exactly unitary cellular automata. After proving that there can be no nontrivial, homogeneous, local, unitary, scalar cellular automaton in one dimension, we weaken the homogeneity conditi

K. Bering, P. H. Damgaard, J. Alfaro

We present a simplified description of higher antibrackets, generalizations of the conventional antibracket of the Batalin-Vilkovisky formalism. We show that these higher antibrackets satisfy relations that are identical to those of higher string products in non-polynomial closed string field theory. Generalization to the case of Sp(2)-symmetry is also formu

T. Christen, M. Buttiker

We use the scattering approach to investigate the nonlinear current-voltage characteristic of mesoscopic conductors. We discuss the leading nonlinearity by taking into account the self-consistent nonequilibrium potential. We emphasize conservation of the overall charge and current which are connected to the invariance under a global voltage shift (gauge inva

Peter Varga

We use the negative replica method, which was originally developed for the study of overfrustation in disordered system, to investigate the statistical behaviour of the cost function of minimax games. These games are treated as hierarchical statistical mechanical systems, in which one of the components is at negative temperature.

Friedemann Brandt

The paper provides a framework for a systematic analysis of the local BRST cohomology in a large class of gauge theories. The approach is based on the cohomology of s+d in the jet space of fields and antifields, s and d being the BRST operator and exterior derivative respectively. It relates the BRST cohomology to an underlying gauge covariant algebra and re

C. Bertoni, F. Finelli, G. Venturi

The Born-Oppenheimer approach to the matter-gravity system is illustrated and the unitary evolution for matter, in the absence of phenomena such as tunnelling or other instabilities, verified. The Born-Oppenheimer approach to the matter-gravity system is illustrated in a simple minisuperspace model and the corrections to quantum field theory on a semiclassic

Y. Funato, P. Hut, S. McMillan, J. Makino

In this paper we describe a new algorithm for the long-term numerical integration of the two-body problem, in which two particles interact under a Newtonian gravitational potential. Although analytical solutions exist in the unperturbed and weakly perturbed cases, numerical integration is necessary in situations where the perturbation is relatively strong. K

Ulrich Weiss

The nonlinear conductance for tunneling through an impurity in a Luttinger liquid and the nonequilibrium DC current noise are calculated exactly for low temperatures. We present a pedestrian pathway towards the exact solution which is based on analytic properties and on a duality between weak and strong backscattering. The prefactor of the T^2 enhancement is

Daijiro Suematsu

We study a consistent explanation for both deficits of solar neutrino and atmospheric neutrino due to the neutrino oscillation induced by the mixing of light neutrinos with a heavy right-handed neutrino. We propose such a phenomenological neutrino mass matrix that realizes this scenario in the simple three generation left- and right- handed neutrino framewor

Daijiro Suematsu

Flavor structure of soft supersymmetry breaking parameters is studied in a certain type of effective supergravity theory derived from moduli/dilaton dominated supersymmetry breaking. Some interesting sum rules for soft scalar masses are presented. They constrain their flavor structure and predict some interesting patterns appeared in soft scalar masses in th

G. M. Moy, J. J. Hope, C. M. Savage

In this paper we present an atom laser scheme using a Raman transition for the output coupling of atoms. A beam of thermal atoms (bosons) in a metastable atomic state $|1 >$ are pumped into a multimode atomic cavity. This cavity is coupled through spontaneous emission to a single mode of another cavity for the ground atomic state, $|2 >$. Above a certain thr

Kenji Mohri

A residue formula which evaluates any correlation function of topological $SU_n$ Yang-Mills theory with arbitrary magnetic flux insertion in two dimensions are obtained. Deformations of the system by two form operators are investigated in some detail. The method of the diagonalization of a matrix valued field turns out to be useful to compute various physica

M. A. Stephanov

We use a random matrix model to study chiral symmetry breaking in QCD at finite chemical potential $μ$. We solve the model and compute the eigenvalue density of the Dirac matrix on a complex plane. A naive ``replica trick'' fails for $μ\neq0$: we find that quenched QCD is not a simple $n\to0$ limit of QCD with $n$ quarks. It is the limit of a theory

Eric Braaten, Yu-Qi Chen

We present a general method for calculating inclusive cross sections for the production of heavy quarkonium states with definite polarization within the NRQCD factorization approach. Cross sections for polarized production can involve additional matrix elements that do not contribute to cross sections for unpolarized production. They can also include interfe

Klaus Ergenzinger

A new semiclassical approach to ionization by an oscillating field is presented. For a delta-function atom, an asymptotic analysis is performed with respect to a quantity h, defined as the ratio of photon energy to ponderomotive energy. This h appears formally equivalent to Planck's constant in a suitably transformed Schroedinger equation and allows semi

D. Bauer, P. Mulser, W. -H. Steeb

Starting from a covariant cycle-averaged Lagrangian the relativistic oscillation center equation of motion of a point charge is deduced and analytical formulae for the ponderomotive force in a travelling wave of arbitrary strength are presented. It is further shown that the ponderomotive forces for transverse and longitudinal waves are different; in the latt

Suk-Joon Lee

Starting from full quantum field theory, various mean field approaches are derived systematically. With a full consideration of external source dependence, the stationary phase approximation of an action gives a nuclear mean field theory which includes quantum correlation effects (such as particle-hole or ladder diagram) in a simpler way than the Brueckner-H

Gregery T. Buzzard, Franc Forstneric

In 1927, Carleman showed that a continuous, complex-valued function on the real line can be approximated in the Whitney topology by an entire function restricted to the real line. In this paper, we prove a similar result for proper holomorphic embeddings. Namely, we show that a proper $\cC^r$ embedding of the real line into $\C^n$ can be approximated in the

Alessandra Carbone

We try to bring to light some combinatorial structure underlying formal proofs in logic. We do this through the study of the Craig Interpolation Theorem which is properly a statement about the structure of formal derivations. We show that there is a generalization of the interpolation theorem to much more naive structures about sets, and then we show how bot

Matthias R. Gaberdiel, Horst G. Kausch

We analyse the fusion products of certain representations of the Virasoro algebra for c=-2 and c=-7 which are not completely reducible. We introduce a new algorithm which allows us to study the fusion product level by level, and we use this algorithm to analyse the indecomposable components of these fusion products. They form novel representations of the Vir

Liu Zhao

An oscillator algebra and the associated Fock space with reflecting boundary and generalized statistics are constructed and is generalized to the multicomponent case. The oscillator algebra depends manifestly on the reflection factor and the statistical (exchange) factor, and the corresponding Fock space can be obtained from that of the usual bosonic oscilla

H. Itoyama, H. Takashino

We derive an infinite sequence of Schwinger-Dyson equations for $N=1$ supersymmetric Yang-Mills theory. The fundamental and the only variable employed is the Wilson-loop geometrically represented in $N=1$ superspace: it organizes an infinite number of supersymmetrizing insertions into the ordinary Wilson-loop as a single entity. In the large $N_{c}$ limit, o

D. S. Oakley, Herschel B. Snodgrass

We attempt to correlate all of the available solar-neutrino capture-rate data with the strong magnetic fields these neutrinos encounter in the solar interior along their Earth-bound path. We approximate these fields using the (photospheric, magnetograph-measured) surface magnetic flux from central latitude bands, time delayed to proxy the solar interior. Our

P. Ramond

The masses of quarks and leptons suggest a strong hierarchical structure. We argue that their patterns can be reproduced through the introduction of a new Abelian symmetry. The data suggest that this symmetry is anomalous. We suggest that the cancellation of its anomalies occur through the Green-Schwarz mechanism. An important check of this idea is that it l

Vittorio Del Duca

Using the helicity formalism, we compute the contribution of a quark-antiquark pair to the tree-level multigluon amplitudes in the high-energy limit. The $\bar{q}\, q$-pair production is absent in the leading-log formalism, but contributes to the next-to-leading corrections to it, and is therefore relevant for the computation of parton-parton scattering in t

A. T. Davies, C. D. Froggatt, G. Jenkins, R. G. Moorhouse

In the electroweak phase transition there arises the problem of baryon number washout by sphaleron transitions, which can be avoided if the phase transition is strongly enough first order. The phase transition in the Standard Model or in the Minimal Supersymmetric Standard Model seems to be too weak to suppress the sphaleron transitions sufficiently. We repo

E. Celeghini, S. De Martino, S. De Siena, M. Rasetti

By resorting to the Fock--Bargmann representation, we incorporate the quantum Weyl--Heisenberg algebra, $q$-WH, into the theory of entire analytic functions. The $q$--WH algebra operators are realized in terms of finite difference operators in the $z$ plane. In order to exhibit the relevance of our study, several applications to different cases of physical i

A. Capella, I. M. Dremin, V. A. Nechitailo, J. Tran Thanh Van

Moment analysis of global multiplicity distribution previously done for $e^{+}e^{-}$ and $hh$ processes is applied to $hA$ and $AA$ collisions. The oscillations of cumulants as functions of their rank are found in all the cases. Some phenomenological approaches and quark-gluon string models are confronted to experimental data. It has been shown that the anal

I. M. Dremin

The recently found excess of high E$_T$ jets over current QCD predictions is attributed to gluon radiation at double scattering process inside a nucleon. The order of magnitude estimate of the cross section fits experimental findings rather well. The specific features of the process are discussed. Various similar hadronic effects related to the short radiati

I. M. Dremin

QCD predictions for moments of parton multiplicity distributions are discussed. The next-to-leading terms and conservation law give rise to the peculiar oscillating shape of some ratio of the moments. The similar shape has been found by moment analysis of hadron multiplicities. Experimental data, theoretical Monte Carlo models and phenomenological fits have

J. C. Romao, F. de Campos, M. A. Garcia-Jareno, M. B. Magro

We illustrate the sensitivities of LEP experiments to leptonic signals associated to models where supersymmetry (SUSY) is realized with spontaneous breaking of R-parity. We focus on missing transverse momentum plus acoplanar muon events arising from lightest neutralino single production $χν$ as well as pair production $χχ$, followed by $χ$ decays, where $χ$

Seung Woo Ham, Sun Kun Oh, Bjong Ro Kim

We examine in detail radiative corrections to the lightest scalar Higgs boson mass due to the top quark and scalar quark loops in the next-to-minimal supersymmetric standard model (NMSSM). We take into account the nondegenerate state for the top scalar quark masses. In our analysis, the mass matrix of the top scalar quark contains the gauge terms. Therefore

Deog Ki Hong

We review dynamical mass generation in three and four dimensional Ableian gauge theories. The basic approach analyzed here is to solve Schwinger-Dyson equations in some approximations. In both cases, the coupling has to be larger than a critical value to have dynamical symmetry breaking. In $QED_4$, chiral symmetry is spontaneouly broken if $α>α_c (\simeq π/

M. Ciuchini, E. Franco, G. Martinelli, L. Silvestrini

We show that, under reasonable hypotheses, it is possible to study two-body non-leptonic weak decays in numerical simulations of lattice QCD. By assuming that final-state interactions are dominated by the nearby resonances and that the couplings of the resonances to the final particles are smooth functions of the external momenta, it is possible indeed to ov

A. Yu. Ignatiev, G. C. Joshi

We study a novel type of extensions of the Standard Model which include a hard mass term for the U(1) gauge field and, optionally, the additional scalar multiplets spontaneously violating the electric charge conservation. Contrary to the case of abelian massive electrodynamics, in these theories the massiveness of photon necessarily implies non-conservation

Aida X. El-Khadra, Andreas S. Kronfeld, Paul B. Mackenzie

This paper presents a formulation of lattice fermions applicable to all quark masses, large and small. We incorporate interactions from previous light-fermion and heavy-fermion methods, and thus ensure a smooth connection to these limiting cases. The couplings in improved actions are evaluated for arbitrary fermion mass~$m_q$, without expansions around small

Norbert Grot, Carlo Rovelli

It is well known that knots are countable in ordinary knot theory. Recently, knots {\it with intersections} have raised a certain interest, and have been found to have physical applications. We point out that such knots --equivalence classes of loops in $R^3$ under diffeomorphisms-- are not countable; rather, they exhibit a moduli-space structure. We charact

Klaus Kirsten, David J. Toms

We present a model which predicts the temperature of Bose-Einstein condensation in atomic alkali gases and find excellent agreement with recent experimental observations. A system of bosons confined by a harmonic oscillator potential is not characterized by a critical temperature in the same way as an identical system which is not confined. We discuss the pr

M. Dzierzawa, M. Zamora, D. Baeriswyl, X. Bagnoud

Weakly coupled superconducting layers are described by the three-dimensional XY model with strong coupling in two directions and weak coupling in the third direction. For the usual Josephson-type interplane coupling the coherence between the layers is lost at the same temperature as that within the layers. Thus a low-temperature layer decoupling due to a pro

Reinhold Egger, Hermann Grabert

We study the density disturbance of a correlated 1D electron liquid in the presence of a scatterer or a barrier. The 2k_F-periodic density profile away from the barrier (Friedel oscillation) is computed for arbitrary electron--electron interaction and arbitrary impurity strength. We find that in presence of correlations, the Friedel oscillation decays slower

Yasuhiro Hatsugai

Edge states in the integral quantum Hall effect on a lattice are reviewed from a topological point of view. For a system with edges which is realized inevitably in an experimental situation, the Hall conductance $σ_{xy}$ is given by a winding number of the edge state on a complex energy surface. A relation between two topological invariants (bulk and edge) i

Zhong-Qi Ma, Xi-Wen Hou, Mi Xie

An algebraic model of Boson-realization is proposed to study the vibrational spectra of a tetrahedral molecule, where ten sets of boson creation and annihilation operators are used to construct the Hamiltonian with $T_{d}$ symmetry. There are two schemes in our model. The first scheme provides an eight-parameter fit to the published experimental vibrational

Glen D. Granzow, Hermann Riecke

We present numerical simulations of coupled Ginzburg-Landau equations describing parametrically excited waves which reveal persistent dynamics due to the occurrence of phase slips in sequential pairs, with the second phase slip quickly following and negating the first. Of particular interest are solutions where these double phase slips occur irregularly in s

A. P. Kasantsev, A. M. Dykhne, V. L. Pokrovsky

It is shown that polarizable neutral systems can drift in crossed magnetic and electric fileds. The drift velocity is perpendicular to both fields, but contrary to the drif t velocity of a charged particle, it exists only, if fields vary in space or in time. We develop an adiabatic theory of this phenomenon and analyze conditions of its experimental observat

Raymond E. White, William C. Keel, Christopher J. Conselice

Partially overlapping galaxies are used to directly determine the effective absorption in spiral galaxy disks. The non-overlapping parts of the galaxies and symmetry considerations are used to reconstruct, via differential photometry, how much background galaxy light is lost in passing through the foreground disks.

L. Tresse, C. Rola, F. Hammer, G. Stasinska

We present a spectroscopic study of the 138 field galaxies to a redshift z = 0.3 from the I-selected Canada-France Redshift Survey. 117(85%) spectra exhibit at least H alpha in emission, the remaining 21(15%) are purely absorption-line spectra. We focus our analysis on spectra with H alpha and H beta in emission, accounting for about half of this low-z sampl

J. Kaluzny, M. Kubiak, M. Szymanski, A. Udalski

Three fields located close to the center of the globular cluster Omega Cen were surveyed in a search for variable stars. We present V-band light curves for 32 periodic variables. This sample includes 10 SX Phe stars, 19 eclipsing binaries, and three likely spotted variables (FK Com or RS CVn type stars). Only 4 of these variables were previously known (inclu

Heino Falcke

In this paper we apply the jet-disk symbiosis model developed for Sgr A* to M81* -- the nucleus of the nearby galaxy M81. The model accurately predicts radio flux and size of M81* for the observed bolometric luminosity of the nuclear source with no major free parameter except for the inclination angle. We point out that the usually applied free, conical jet

S. P. Ellingsen, R. P. Norris, P. J. Diamond, P. M. McCulloch

We present milliarcsecond resolution images of the 6.7 and 12.2 GHz methanol maser emission associated with the well-known star formation region NGC 6334F. The images agree well with previous lower resolution observations, but detect approximately double the number of spots seen in the earlier work. Comparison of the relative positions of the 6.7 and 12.2 GH

Robert M. Cavallo, Allen V. Sweigart, Roger A. Bell

We study the production of Na and Al around the hydrogen shell of two red-giant sequences of different metallicity in order to explain the abundance variations seen in globular cluster stars in a mixing scenario. Using detailed stellar models together with an extensive nuclear reaction network, we have calculated the distribution of the various isotopic abun

Fernando Torres

We prove that the constellation of Weierstrass points characterizes the isomorphism-class of double covering of curves of genus large enough.

Carlos Simpson

This is partly a survey article on nonabelian Hodge theory, but we also give proofs of results that have only been announced elsewhere. In the introduction we discuss a wide range of recent work on this subject and give some references. In the body of the paper, we discuss Corlette's nonabelian Hodge theorem, Hitchin's quaternionic structure on the m

N. G. Deshpande, B. Dutta, E. Keith

We present a model based on the gauge group SU(2)$_L\times$SU(2)$_R\times$SU(4)$_C$ with gauge couplings that are found to be unified at a scale $M_G$ near the string unification scale. The model breaks to the minimal supersymmetric standard model at a scale $M_I\sim 10^{12}$ GeV, which is instrumental in producing a neutrino in a mass range that can serve a

Alexander N. Korotkov

It is shown that the noise-limited charge sensitivity of a single-electron transistor using superconductors (of either $SISIS$ or $NISIN$ type) operating near the threshold of quasiparticle tunneling, can be considerably higher than that of a similar transistor made of normal metals or semiconductors. The reason is that the superconducting energy gap, in con

L. Rozansky

P. Melvin and H. Morton studied the expansion of the colored Jones polynomial of a knot in powers of q-1 and color. They conjectured an upper bound on the power of color versus the power of q-1. They also conjectured that the bounding line in their expansion generated the inverse Alexander-Conway polynomial. These conjectures were proved by D. Bar-Natan and

Remo Garattini

We consider a homogeneous space $X=(X,d,m) $ of dimension $ν\geq1$ and a local regular Dirichlet form in $L^{2}(X,m) .$ We prove that if a Poincaré inequality holds on every pseudo-ball $B(x,R) $ of $X$, then an Harnack's inequality can be proved on the same ball with local characteristic constant $c_{0}$ and $c_{1}$

Jonathan A. Bagger

These lectures contain an introduction to the theory and practice of weak-scale supersymmetry. They begin with a discussion of the hierarchy problem and the motivation for weak-scale supersymmetry. They continue by developing the coset approach to superfields. They use superfield techniques to construct the minimal supersymmetric version of the standard mode

E. J. Copeland, P. M. Saffin

In an Abelian gauge symmetry, spontaneously broken at a first order phase transition, we investigate the evolution of two and three bubbles of the broken symmetry phase. The full field equations are evolved and we concentrate in particular on gauge invariant quantities, such as the magnetic field and the integral around a closed loop of the phase gradient. A

F. Buccella, G. Miele, N. Tancredi

Quantum statistical distributions for the partons provide a fair description of deep inelastic scattering data at $Q^2 = 3$ and $10 (GeV/c)^2$. The study of the polarized structure functions seems to suggest an alternative possible solution of the {\it spin crisis} based on the Pauli principle. In this scheme, in fact, the defects of the Gottfried sum rule a

C. Lucchesi

I outline various derivations of the non-Abelian Kubo equation, which governs the response of a quark-gluon plasma to hard thermal perturbations. In the static case, it is proven that gauge theories do not support hard thermal solitons. Explicit solutions are constructed within an SU(2) Ansatz and they are shown to support the general result. The time-depend

S. Ciulli, S. Ispas, M. K. Pidcock

Studies of models of current flow behaviour in Electrical Impedance Tomography (EIT) have shown that the current density distribution varies extremely rapidly near the edge of the electrodes used in the technique. This behaviour imposes severe restrictions on the numerical techniques used in image reconstruction algorithms. In this paper we have considered a

Martin C. Smith, Scott S. Willenbrock

We calculate the O(alpha_s) and O(alpha_W m_t^2/M_W^2) corrections to the production of a single top quark via the weak process q qbar -> t bbar at the Fermilab Tevatron and the CERN Large Hadron Collider. An accurate calculation of the cross section is necessary in order to extract |V_tb| from experiment.

N. N. Achasov

It is shown that $BR(χ_{b1}(1P)\rightarrow Z\rightarrow e^+e^-)\simeq 3.3\cdot 10^{-7}$, $BR(χ_{b1}(2P)\rightarrow Z\rightarrow e^+e^-)\simeq 4.1\cdot 10^{-7}$ and $BR(χ_{c1}(1P)\rightarrow Z\rightarrow e^+e^-)\simeq 10^{-8}$ that give a good chance to search for the direct production of pseudovector $^3P_1$ heavy quarkonia in $e^+e^-$ collisions ($e^+e^-\ri

Dae Sung Hwang, C. S. Kim, Wuk Namgung

Within the ACCMM model the average kinetic energy of heavy quark in a heavy-light meson is calculated as $\langle {\bf p}^2 \rangle = {3 \over 2} {p_{_F}}^2$, solely from the fact that the Gaussian momentum probability distribution has been taken in the ACCMM model. Therefore, the Fermi momentum parameter $p_{_F}$ of the ACCMM model is not a truly free param

Michael Finkelberg, Vadim Schechtman

A report on the works hep-th/9411050, q-alg/9412017, q-alg/9503013, q-alg/9506011 and a joint work with R.Bezrukavnikov.

Jan F. van Diejen

Limiting cases are studied of the Koornwinder-Macdonald multivariable generalization of the Askey-Wilson polynomials. We recover recently and not so recently introduced families of hypergeometric orthogonal polynomials in several variables consisting of multivariable Wilson, continuous Hahn and Jacobi type polynomials, respectively. For each class of polynom

J. F. van Diejen

Elementary properties of the Koornwinder-Macdonald multivariable Askey-Wilson polynomials are discussed. Studied are the orthogonality, the difference equations, the recurrence relations, and the orthonormalization constants for these polynomials. Essential in our approach are certain commuting difference operators simultaneously diagonalized by the polynomi

Takashi Takebe

An elliptic analogue of the $q$ deformed Knizhnik-Zamolodchikov equations is introduced. A solution is given in the form of a Jackson-type integral of Bethe vectors of the XYZ-type spin chains.

S. S. Avancini, F. F. de Souza Cruz, J. R. Marinelli, D. P. Menezes

A deformed boson mapping of the Marumori type is derived for an underlying $su(2)$ algebra. As an example, we bosonize a pairing hamiltonian in a two level space, for which an exact treatment is possible. Comparisons are then made between the exact result, our q- deformed boson expansion and the usual non - deformed expansion.

S. Jeschonnek, S. Krewald, A. Szczurek

The $^{12}C(e,e'p)$ reaction is analyzed in a model which explicitly includes final state interactions due to the coupling of the proton and neutron emission channels. We find that the effects of the final state interactions due to charge exchange reactions are important to get a good description of the symmetry properties of the recently measured Mainz

S. M. Johns, P. J. Ellis, J. M. Lattimer

We approximate boson thermodynamic integrals as polynomials in two variables chosen to give the correct limiting expansions and to smoothly interpolate into other regimes. With 10 free parameters, an accuracy of better than 0.009\% is achieved for the pressure, internal energy density and the number density. We also revisit the fermion case, originally addre

Hector E. Lomeli, James D. Meiss

Explicit formulae are given for the saddle connection for an integrable family of standard maps studied by Suris. A generalization of Melnikov's method shows that, upon perturbation, this connection is destroyed. We give explicit formula for the first order approximation of the area of the lobes of the resultant turnstile. It is shown that the lobe area is e

Reinhard Oehme, Wentao Xu

For the structure functions of the quark propagator, the asymptotic behavior is obtained for general, linear, covariant gauges, and in all directions of the complex $k^2$-plane. Asymptotic freedom is assumed. Corresponding previous results for the gauge field propagator are important in the derivation. Except for coefficients, the leading asymptotic terms ar

Thomas Heinzl

We review the status of quantising (non-abelian) gauge theories using different versions of a Hamiltonian formulation corresponding to Dirac's instant and front form of dynamics, respectively. In order to control infrared divergences we work in a finite spatial volume, chosing a torus geometry for convenience. We focus on the determination of the physica

A. Gonzalez-Arroyo, A. Montero

We show that certain classical SU(2) pure gauge configurations give rise to a non-zero string tension. We then investigate cooled configurations generated by Monte Carlo simulations on the lattice and find similar properties. We infer evidence in favour of a classical model of Confinement.

Heng Fan, Bo-yu Hou, Kang-jie Shi, Zhong-xia Yang

By using the intertwiner and face-vertex correpondence relation, we obtain the Bethe ansatz equation of eight vertex model with open boundary condtitions in the framework of algebraic Bethe ansatz method. The open boundary condition under consideration is the general solution of the reflection equation for eight vertex model with only one restriction on the

Maciej A. Nowak, Gábor Papp, Ismail Zahed

We suggest that the lattice Dirac spectra in QCD at finite temperature may be understood using a gaussian unitary ensemble for Wilson fermions, and a chiral gaussian unitary ensemble for Kogut-Susskind fermions. For Kogut-Susskind fermions, the lattice results by the Columbia group are in good agreement with the spectral distribution following from a cubic e

Nikolaos Kidonakis, George Sterman

We discuss the resummation of distributions that are singular at the elastic limit of partonic phase space (partonic threshold) in QCD hard-scattering cross sections, such as heavy quark production. We show how nonleading soft logarithms exponentiate in a manner that depends on the color structure within the underlying hard scattering. This result generalize

Amol S. Dighe, Michael Gronau, Jonathan L. Rosner

Phases of elements of the Cabibbo-Kobayashi-Maskawa (CKM) matrix can be obtained using decays of $B$ mesons to $π^+ π^-$, $π^\pm K^\mp$, and $π^+ K^0$ or $π^- \overline{K}^0$. For $B^0~{\rm or}~ \overline{B}^0 \to π^+ π^-$, one identifies the flavor of the neutral $B$ meson at time of production and studies the time-dependence of the decay rate. The other pr

Michael Pluemacher

The cosmological baryon asymmetry can be explained by the nonperturbative electroweak reprocessing of a lepton asymmetry generated in the out-of-equilibrium decay of heavy right-handed Majorana neutrinos. We analyze this mechanism in detail in the framework of a SO(10)-subgroup. We take three right-handed neutrinos into account and discuss physical neutrino

C. Q. Geng, I. J. Hsu, Y. C. Lin

We calculate long distance contributions to $K\toπν\barν\,,\ ππν\barν$, and $πππν\barν$ modes within the framework of chiral perturbation theory. We find that these contributions to decay rates of $K\to πν\barν$ and $K\to ππν\barν$ in the chiral logarithmic approximation are at least seven orders of magnitude suppressed relative to those from the short dista

Christof Gattringer

We analyze the chiral Schwinger model on an infinite lattice using the continuum definition of the fermion determinant and a linear interpolation of the lattice gauge fields. For non-compact and Wilson formulation of the gauge field action it is proven that the effective lattice model is Osterwalder-Schrader positive, which is a sufficient condition for the

W. Franzki, J. Jersak. R. Welters

We generalize the $N_F=2$ Schwinger model on the lattice by adding a charged scalar field. In this so-called $χUϕ_2$ model the scalar field shields the fermion charge, and a neutral fermion, acquiring mass dynamically, is present in the spectrum. We study numerically the mass of this fermion at various large fixed values of the gauge coupling by varying the

John Ellison

We present electroweak physics results from the DZero experiment using data from collisions at \sqrt{s} = 1.8 TeV, concentrating on single W and Z production cross sections and the production of electroweak gauge boson pairs. The inclusive cross sections times branching ratios for W and Z production have been measured and are used to determine the inclusive

Matt Visser

Building on a pair of earlier papers, I investigate the various point-wise and averaged energy conditions for the quantum stress-energy tensor corresponding to a conformally-coupled massless scalar field in the in the (1+1)-dimensional Schwarzschild spacetime. Because the stress-energy tensors are analytically known, I can get exact results for the Hartle--H

Matt Visser

I show that in the Boulware vacuum (1) all standard (point-wise and averaged) energy conditions are violated throughout the exterior region---all the way from spatial infinity down to the event horizon, and (2) outside the event horizon the standard point-wise energy conditions are violated in a maximal manner: they are violated at all points and for all nul

Matt Visser

It is well-known that gravitationally induced vacuum polarization often violates the point-wise energy conditions and sometimes violates the averaged energy conditions. In this paper I begin a systematic attack on the question of where and by how much the various energy conditions are violated. I work in the test-field limit, and focus on conformally coupled

John Quigg

For partial automorphisms of $C^*$-algebras, Takai-Takesaki crossed product duality tends to fail, in proportion to the extent to which the partial automorphism is not an automorphism.

John Quigg, Iain Raeburn

Partial actions of discrete groups on $C^*$-algebras and the associated crossed products have been studied by Exel and McClanahan. We characterise these crossed products in terms of the spectral subspaces of the dual coaction, generalising and simplifying a theorem of Exel for single partial automorphisms. We then use this characterisation to identify the Cu

Boris I Shraiman, Eric D Siggia

The stationary condition (Hopf equation) for the ($n$+1) point correlation function of a passive scalar advected by turbulent flow is argued to have an approximate $SL(n, R)$ symmetry which provides a starting point for the perturbative treatment of less symmetric terms. The large scale anisotropy is found to be a relevant field, in contradiction with Kolmog

R. K. Kamilla, X. G. Wu, J. K. Jain

The low-energy excitations of filled Landau levels (LL's) of electrons involve promotion of a single electron from the topmost filled LL to the lowest empty LL. These are called excitons or collective modes. The incompressible fractional quantum Hall states are understood as filled LL's of composite fermions, and the low-energy neutral excitations ar

R. K. Kamilla, X. G. Wu, J. K. Jain

It is verified that, at small Zeeman energies, the charged excitations in the vicinity of 1/3 filled Landau level are skyrmions of composite fermions, analogous to the skyrmions of electrons near filling factor unity. These are found to be relevant, however, only at very low magnetic fields.