March 1993 arXiv papers — page 2

S. Kalyana Rama

We describe a static solution for $d = 2$ critical string theory including the tachyon $T$ but with its potential $V (T)$ set to zero. This solution thus incorporates tachyon back reaction and, when $T = 0$, reduces to the black hole solution. When $T \neq 0$ we find that (1) the Schwarzschild horizon of the above black hole splits into two, resembling Reiss

Yu. Makeenko

I show that the strong coupling solution of the Kazakov--Migdal model with a general interaction potential $V(Φ)$ in $D$ dimensions coincides at large $N$ with that of the hermitean one-matrix model with the potential $\tilde{V}(Φ)$: $$ (2D-1)\tilde{V}'= (D-1)V'+ D\sqrt{(V')^2+4(1-2D)Φ^2}, $$ whose solution is known. The proof is given for an eve

Samson L. Shatashvili

A direct derivation of the string field theory action in the Witten's background independent open string theory for the case when ghosts and matter are decoupled is given and consequences are discussed.

T. D. Palev, N. I. Stoilova

We formulate a conjecture, stating that the algebra of $n$ pairs of deformed Bose creation and annihilation operators is a factor-algebra of $U_q[osp(1/2n)]$, considered as a Hopf algebra, and prove it for $n=2$ case. To this end we show that for any value of $q$ $U_q[osp(1/4)]$ can be viewed as a superalgebra, freely generated by two pairs $B_1^\pm$, $B_2^\

V. I. Man'ko, R. Vilela Mendes

Brownian motion may be embedded in the Fock space of bosonic free field in one dimension.Extending this correspondence to a family of creation and annihilation operators satisfying a q-deformed algebra, the notion of q-deformation is carried from the algebra to the domain of stochastic processes.The properties of q-deformed Brownian motion, in particular its

F. M. Borzumati, B. A. Kniehl, G. Kramer

We calculate in next-to-leading order inclusive cross sections of single-particle production via resolved photons in $ep$ collisions at HERA. Transverse-momentum and rapidity distributions are presented and the scale dependence is studied. The results are compared with first experimental data from the H1 Collaboration at HERA.

J. Ellis, J. Lopez, D. Nanopoulos, K. Olive

We discuss systematically the fermion mass and mixing matrices in a generic \linebreak field-theoretical flipped $SU(5)$ model, with particular applications to neutrino and baryon number-changing physics. We demonstrate that the different quark flavour branching ratios in proton decay are related to the Cabibbo-Kobayashi-Maskawa angles, whereas the lepton fl

S. Kumano

Deep inelastic structure functions $F_2^A(x)$ are investigated in a $Q^2$ rescaling model with parton recombination effects. We find that the model can explain experimentally measured $F_2^A(x)$ structure functions reasonably well in the wide Bjorken$-x$ range ($0.005<x<0.8$). In the very small $x$ region ($x<0.02$), recombination results are very sensitive

Andreas S, Kronfeld, Paul B. Mackenzie

Review of results from lattice QCD of relevance to standard-model phenomenology, to appear in Annual Review of Nuclear and Particle Science. KEY WORDS: hadron masses, quark mixing (CKM) matrix, weak matrix elements, strong coupling constant.

R. Loll

We point out an incompleteness of formulations of gravitational and gauge theories that use traces of holonomies around closed curves as their basic variables. It is shown that in general such loop variables have to satisfy certain inequalities if they are to give a description equivalent to the usual one in terms of local gauge potentials.

Alan D. Rendall

It is shown that there exist families of asymptotically flat solutions of the Einstein equations coupled to the Vlasov equation describing a collisionless gas which have a Newtonian limit. These are sufficiently general to confirm that for this matter model as many families of this type exist as would be expected on the basis of physical intuition. A central

Sourendu Gupta

Hysteresis is observed at second order phase transitions. Universal scaling formulæ for the areas of hysteresis loops are written down. Critical exponents are defined, and related to other exponents for static and dynamic critical phenomena. These relations are verified with Langevin dynamics in both the critical and tricritical mean-field models. A finite-s

Leon Balents, Daniel S. Fisher

The equilibrium statistical mechanics of a d dimensional ``oriented&#39;&#39; manifold in an N+d dimensional random medium are analyzed in d=4-epsilon dimensions. For N=1, this problem describes an interface pinned by impurities. For d=1, the model becomes identical to the directed polymer in a random medium. Here, we generalize the functional renormalizatio

Heiko Rieger, A. P. Young

The phase transition of the three--dimensional random field Ising model with a discrete ($\pm h$) field distribution is investigated by extensive Monte Carlo simulations. Values of the critical exponents for the correlation length, specific heat, susceptibility, disconnected susceptibility and magnetization are determined simultaneously via finite size scali

U. C. Taeuber, F. Schwabl

In isotropic systems below the transition temperature, the massless Goldstone modes imply critical infrared singularities in the statics and dynamics along the entire coexistence curve. We examine the important question whether these coexistence anomalies are of relevance also in more realistic systems displaying anisotropies. By applying a generalized renor

Peter L. Biermann, Richard G. Strom

We develop a theory to account for the cosmic ray spectrum between 1 GeV and 10^4 GeV following the earlier papers of this series. We use the basic concept that the cosmic ray particles are accelerated in a supernova shock that travels through the interstellar medium. Physically important ingredients besides the presence of a strong shock are diffusion, drif

A. Morozov

The theory of matrix models is reviewed from the point of view of its relation to integrable hierarchies. Discrete 1-matrix, 2-matrix, ``conformal&#39;&#39; (multicomponent) and Kontsevich models are considered in some detail, together with the Ward identites (``W-constraints&#39;&#39;), determinantal formulas and continuum limits, taking one kind of models

Nuria Rius, Elizabeth H. Simmons

We consider experimental signatures of the standard model&#39;s minimal supersymmetric extension with a continuous $U(1)_R$ symmetry (MR model). We focus on the ability of existing and planned electron-positron colliders to probe this model and to distinguish it from both the standard model and the standard model&#39;s minimal supersymmetric extension with a

D. B. Fairlie, J. Nuyts

A general deformation of the Heisenberg algebra is introduced with two deformed operators instead of just one. This is generalised to many variables, and permits the simultaneous existence of coherent states, and the transposition of creation operators.

M. Dine, A. Kagan, R. G. Leigh

One possible solution to the strong CP problem is that CP is an exact symmetry, spontaneously broken at some scale. Some years ago, Nelson and Barr suggested a mechanism for obtaining $θ=0$ at tree level in this framework, and showed that radiative corrections were small in some non-supersymmetric models. Further investigations suggested that the same could

Chihong Chou

Based on a simple observation that a classical second order differential equation may be decomposed into a set of two first order equations, we introduce a Hamiltonian framework to quantize the damped systems. In particular, we analyze the system of a linear damped harmonic oscillator and demonstrate that the time evolution of the Schrödinger equation is una

O. M. Khudaverdian, A. P. Nersessian

An invariant definition of the operator $Δ$ of the Batalin-Vilkovisky formalism is proposed. It is defined as the divergence of a Hamiltonian vector field with an odd Poisson bracket (antibracket). Its main properties, which follow from this definition, as well as an example of realization on Kählerian supermanifolds, are considered. The geometrical meaning

Akika Nakamichi

We clarify the relation between 2-form Einstein gravity and its topological version. The physical space of the topological version is contained in that of the Einstein gravity. Moreover a new vector field is introduced into 2-form Einstein gravity to restore the large symmetry of its topological version. The wave function of the universe is obtained for each

Taku Uchino

A canonical quantization for two dimensional gravity models, including a dilaton gravity model, is performed in a way suitable for the light-cone gauge. We extend the theory developed by Abdalla {\it et.al.}\cite{AM} and obtain the correlation functions by using the screening charges of the symmetry algebra. It turns out that the role of the cosmological con

Alexander Sevrin, Kris Thielemans, Walter Troost

As a preparation for the study of {\it arbitrary} extensions of $d=2$ gravity we present a detailed investigation of $SO(N)$ supergravity. By gauging a chiral, nilpotent subgroup of the $OSp(N|2)$ Wess-Zumino-Witten model we obtain an all order expression for the effective action. Reality of the coupling constant imposes the usual restrictions on $c$ for $N=

Chanju Kim, Choonkyu Lee, Pyungwon Ko, Bum-Hoon Lee

A general non-relativistic field theory on the plane with couplings to an arbitrary number of abelian Chern-Simons gauge fields is considered. Elementary excitations of the system are shown to exhibit fractional and mutual statistics. We identify the self-dual systems for which certain classical and quantal aspects of the theory can be studied in a much simp

Paul Langacker

The implications of recent precision $Z$-pole, $W$ mass, and weak neutral current data for testing the standard electroweak model, constraining the $t$ quark and Higgs masses, \alsz, and grand unification are discussed. A fit to all data yields $\siz = 0.2328 \pm 0.0007$ (\msb) or $\sinn \equiv 1 - \mw^2/\mz^2 = 0.2267 \pm 0.0024$ (on-shell), where the uncer

Lawrence J. Hall, Andrija Rašin

The relations ${ {|V_{ub}|} \over {|V_{cb}|} } = \sqrt{ { m_u \over m_c } }$ and ${ {|V_{td}|} \over {|V_{ts}|} } = \sqrt{ { m_d \over m_s } }$ are significant successes of some specific models for quark masses. We show that these relations are more general, resulting from a much wider class of models. Consequences of these predictions for CP violating asymm

G. Cvetic, C. S. Kim

It is possible that the standard model (SM) is replaced around some transition energy $\E_{tr}$ by a new, possibly Higgsless, ``flavor gauge theory&#39;&#39; such that the Yukawa (running) parameters of SM at $E \sim \E_{tr}$ show up an (approximate) flavor democracy (FD). We investigate the latter possibility by studying the renormalization group equations

Y. Y. Keum, X. Y. Pham

We point out that the rare decay mode $W^{\pm} \rightarrow γ+ D^{\pm}_{s} $ could be spectacularly enhanced, with a branching ratio around $10^{-6} $ which is three order of magnitude larger than previous predictions. Its observation will determine the W boson mass with great accuracy, providing additional high precision tests of the standard model, as well

F. del Aguila, Mirjam Cvetic, Paul Langacker

We point out that at future hadron colliders the ratio of cross sections for $pp\to Z&#39;\to \ell^+\ell^-$ in two rapidity bins is a useful probe of the relative couplings of the $Z&#39;$ to $u$ and $d$ quarks. Combined with the forward-backward asymmetry, the rare decay modes $Z&#39;\to W \ellν_\ell$, and three associated productions $pp\to Z&#39;V$ ($V=Z,

Ulf-G. Meißner

In the first part of these lectures, I consider chiral perturbation theory in the presence of matter fields. It allows to systematically work out the consequences of the broken chiral symmetry of QCD. As examples, threshold pion photo- and electroproduction and (spin-flip) nucleon Compton scattering are considered. The second part deals with the quark struct

J. F. Gunion

I summarize the abilities of LEP-II, the SSC/LHC hadron colliders, and a future high energy $\epem$ collider (NLC) to detect the Higgs bosons of the Minimal Supersymmetric Model (MSSM). I then review the unique capabilities of a back-scattered laser beam facility (BSLBF) at the NLC for detecting the heavier neutral Higgs bosons (the $\hh$ and $\ha$) of the M

Wolfgang Haeusler, Bernhard Kramer, PTB Braunschweig

The spectral properties of up to four interacting electrons confined within a quasi one--dimensional system of finite length are determined by numerical diagonalization including the spin degree of freedom. The ground state energy is investigated as a function of the electron number and of the system length. The limitations of a description in terms of a cap

Predrag Cvitanović, Bruno Eckhardt

Discrete symmetries of dynamical flows give rise to relations between periodic orbits, reduce the dynamics to a fundamental domain, and lead to factorizations of zeta functions. These factorizations in turn reduce the labor and improve the convergence of cycle expansions for classical and quantum spectra associated with the flow. In this paper the general fo

Alexander A. Migdal

The incompressible fluid dynamics is reformulated as dynamics of closed loops $C$ in coordinate space. This formulation allows to derive explicit functional equation for the generating functional $Ψ[C]$ in inertial range of spatial scales, which allows the scaling solutions. The requirement of finite energy dissipation rate leads then to the Kolmogorov index

A. A. Nersesyan, A. Luther, F. V. Kusmartsev

Scaling properties of a self-dual field-theoretical model, describing two weakl$spinless Luttinger chains, are studied. A crossover to a sine-Gordon massive phase, with strongly developed two-particleinterchain correlations, is described. It is argued that, in a wide range of the in-chain interaction, renormalization of the interchain hopping amplitude is de

J. W. van Holten

The dynamics of relativistic spinning particles in strong external electromagnetic or gravitational fields is discussed. Spin-orbit coupling is shown to affect such relativistic phenomena as time-dilation and perihelion shift. Possible applications include muon decay in a magnetic field and the dynamics of neutron stars in binary systems.

Petr Kurka

We conceive finite automata as dynamical systems on discontinuum and investigate their factors. Factors of finite automata include many well-known simple dynamical systems, e.g. hyperbolic systems and systems with finite attractors. In the quadratic family on the real interval, factors of finite automata include all systems with finite number of periodic poi

K. -H. Mütter

An evolution equation for the expectation values of the Boltzmann factor between monomer valence bond states is derived. It contains the whole information on the thermodynamical and magnetic properties of the spin $\frac{1}{2}$ quantum Heisenberg model. A new approximation scheme is proposed and studied in the thermodynamical limit.

Hikaru Kawai, Yoshihisa Kitazawa, Masao Ninomiya

We formulate a renormalizable quantum gravity in $2+ε$ dimensions by generalizing the nonlinear sigma model approach to string theory. We find that the theory possesses the ultraviolet stable fixed point if the central charge of the matter sector is in the range $0~<~c~<~25$. This may imply the existence of consistent quantum gravity theory in 3 and 4 dimens

Robert Fisch, Janko Gravner, David Griffeath

The Greenberg-Hastings Model (GHM) is a family of multitype cellular automata that emulate excitable media, exhibiting the nucleation and spiral formation characteristic of such complex systems. In this paper we study the asymptotic frequency of nucleation in 2-d GHM dynamics as the number k of types, or colors, becomes large. Starting from uniform product m

Janko Gravner, David Griffeath

We study the asymptotic shape of the occupied region for monotone deterministic dynamics in d-dimensional Euclidean space parametrized by a threshold theta, and a Borel set N with positive and finite Lebesgue measure. If A_n denotes the occupied set of the dynamics at integer time n, then A_n+1 is obtained by adjoining any point x for which the volume of ove

R. D. Parmentier

Magnetic flux quanta, of value h/2e, in long Josephson junctions behave as (quasi) solitons. Fluxon dynamical states are well described by a perturbed sine-Gordon equation model, with boundary conditions determined by the junction geometry and by externally applied magnetic fields, and they give rise to readily measurable physical phenomena, such as step str

A. Mikhailov

The connection is obtained between Ward identities and W-constraints in Generalized Kontsevich Model with the potential $X^4/4$. We show that Ward identities include W-constraints (and do not include any other constraints) for this potential and make some observations in favour of the same connection for the model with the potential of the form $X^{(K+1)}/(K

Christian Grosche

The path integral for the propagator is expanded into a perturbation series, which can be exactly summed in the case of $δ$-function perturbations giving a closed expression for the (energy-dependent) Green function. Making the strength of the $δ$-function perturbation infinite repulsive, produces a totally reflecting boundary, hence giving a path integral s

F. David

Content: 1. Introduction 2. Regge calculus and dynamical triangulations Simplicial manifolds and piecewise linear spaces - dual complex and volume elements - curvature and Regge action - topological invariants - quantum Regge calculus - dynamical triangulations 3. Two dimensional quantum gravity, dynamical triangulations and matrix models continuum formulati

E. Elizalde, S. Leseduarte, S. Zerbini

Making use of inverse Mellin transform techniques for analytical continuation, an elegant proof and an extension of the zeta function regularization theorem is obtained. No series commutations are involved in the procedure; nevertheless the result is naturally split into the same three contributions of very different nature, i.e. the series of Riemann zeta f

E. Elizalde, S. Naftulin, S. D. Odintsov

A general model of dialton-Maxwell gravity in two dimensions is investigated. The corresponding one-loop effective action and the generalized $β$-functions are obtained. A set of models that are fixed points of the renormalization group equations are presented.

Sharon L. Vadas

In this paper, we study the evolution of a relativistic, superhorizon-sized void embedded in a Friedmann-Robertson-Walker universe. We numerically solve the spherically symmetric general relativistic equations in comoving, synchronous coordinates. Initially, the fluid inside the void is taken to be homogeneous and nonexpanding. In a radiation- dominated univ

Arild Skjold, Per Osland

We discuss how correlations among momenta of the decay products may yield information about the CP-parity of the Higgs particle. These are correlations of decay planes defined by the momenta of pairs of particles as well as correlations between energy differences. Our study includes finite-width effects. In the narrow-width approximation the angular correlat

Bjarte Kileng

We discuss the effects of mixing of scalars belonging to left-- and right--chiral MSSM super--multiplets on the process ${g}{g}\rightarrow \hnl \rightarrow \ga\ga$, which is a promising channel for the discovery of the lightest CP--even MSSM Higgs boson at the LHC and the SSC. The effects of the left--right scalar mixing are small in most of parameter space.

Palash B Pal

If a fermion is travelling through a medium, it can have matter-induced magnetic and electric dipole moments. These contributions conserve chirality, and can be non-vanishing even for a Majorana neutrino. Several implications for neutrino physics are discussed.

B. de Carlos, J. A. Casas

We examine the electroweak breaking mechanism in the minimal supersymmetric standard model (MSSM) using the {\em complete} one-loop effective potential $V_1$. First, we study what is the region of the whole MSSM parameter space (i.e. $M_{1/2},m_o,μ,...$) that leads to a succesful $SU(2)\times U(1)$ breaking with an acceptable top quark mass. In doing this it

L. Lin, I. Montvay, G. Muenster, M. Plagge

The vacuum stability lower bound on the mass of the Higgs boson is numerically investigated in an $SU(2)_L \otimes SU(2)_R$ symmetric Yukawa model, which describes two heavy degenerate fermion doublets in the limit of vanishing gauge couplings. Good agreement with perturbation theory is found, although the couplings are strong. The upper bound on the fermion

Gunter Schuetz

We study a one-dimensional anisotropic exclusion process describing particles injected at the origin, moving to the right on a chain of $L$ sites and being removed at the (right) boundary. We construct the steady state and compute the density profile, exact expressions for all equal-time n-point density correlation functions and the time-dependent two-point

M. Guagnelli, E. Marinari, G. Parisi

In this note we study the mean field equations for the $3d$ Random Field Ising Model. We discuss the phase diagram of the model, and we address the problem of finding if such equations admit more than one solution. We find two different critical values of $β$: one where the magnetization takes a non-zero expectation value, and one where we start to have more

M. Karbach, K. -H. Mütter, P. Ueberholz, H. Kröger

The evolution equation for the expectation values of the Boltzmann factor between valence bond states is evaluated in lowest order of the dimer cluster expansion. Explicit formulas are given for the internal energy and the specific heat of the d-dimensional antiferromagnetic Heisenberg model.

G. Schuetz, E. Domany

We consider an exclusion process, with particles injected with rate $α$ at the origin and removed with rate $β$ at the right boundary of a one-dimensional chain of sites. The particles are allowed to hop onto unoccupied sites, to the right only. For the special case of $α=β=1$ the model was solved previously by Derrida et al. Here we extend the solution to g

Bruno Eckhardt

[[ RM: A review paper on cycle expansions. I quote the introduction: in section (2) ]] I will summarize Gutzwiller&#39;s theory for the spectrum of eigenenergies and extend it to diagonal matrix elements as well. The derivation of the associated zeta function is given (2.2) and the identification of suitable scaling variables discussed (2.3). In section 3 to

D. L. Shepelyansky

The phenomenon of stabilization of highly excited states of hydrogen atom in a strong monochromatic field is discussed. Approximate description of dynamics by the introduced Kramers map allows to understand the main properties of this phenomenon on the basis of analogy with the Kepler map. Analogy between the stabilization and the channeling of particles in

M. Milgrom

We investigate particle laws of motion derived from nonstandard kinetic actions of a special form. We are guided by a phenomenological scheme--the modified dynamics (MOND)--that imputes the mass discrepancy observed in galactic systems to a departure from Newtonian dynamics below a certain acceleration scale a0. In the limit a0 goes to 0 the theory goes to N

John D Barrow, Andrew R Liddle

We investigate models of `intermediate' inflation, where the scale factor $a(t)$ grows as $a(t) = \exp (A t^f)$, $0 < f < 1$, $A$ constant. These solutions arise as exact analytic solutions for a given class of potentials for the inflaton $\phi$. For a simpler class of potentials falling off as a power of $\phi$ they arise as slow-roll solutions, and in part

Jan Stevens

We determine the versal deformation of cones, in the simplest case: cones over hyperelliptic curves of high degree. In particular, we show that for degree $4g+4$, the highest degree for which interesting deformations exist, the number of smoothing components is $2^{2g+1}$ ($g\neq3$). We review in a general setting the relation of $T^1(-1)$ with Wahl&#39;s Ga

Nathan Berkovits

In two recent papers, a new method was developed for calculating ten-dimensional superstring amplitudes with an arbitrary number of loops and external massless particles, and for expressing them in manifestly Lorentz-invariant form. By explicitly checking for divergences when the Riemann surface degenerates, these amplitudes are proven to be finite. By choos

Richard Durrett, David Griffeath

We study two families of excitable cellular automata known as the Greenberg-Hastings Model (GHM) and the Cyclic Cellular Automaton (CCA). Each family consists of local deterministic oscillating lattice dynamics, with parallel discrete-time updating, parametrized by the range of interaction, the &#34;shape&#34; of its neighbor set, threshold value for contact

Chang-Pu Sun

In this papper, a quantum dynamical model describing the quantum measurement process is presented as an extensive generalization of the Coleman-Hepp model. In both the classical limit with very large quantum number and macroscopic limit with very large particle number in measuring instrument, this model generally realizes the wave packet collapse in quantum

Ansar Fayyazuddin

The complete set of ground state wave functions for N anyons in an external magnetic field on the torus is found. The cases when the filling factor is less than or equal to one are considered. The single valued description of anyons is employed through out by coupling bosons to a Chern-Simons field. At the end, the Chern-Simons interaction is removed by a si

David London

I review the current limits on the mixing of ordinary and exotic fermions.

R. D. Field, P. A. Griffin

The jet-jet profile, or detailed manner, in which transverse energy and mass are distributed around the jet-jet system resulting from the hadronic decay of a $Z$ boson in the process Higgs$\to ZZ$ at a proton-proton collider energy of $40\tev$ is carefully examined. Two observables are defined that can be used to help distinguish the $\ell^+\ell^-$-jet-jet s

Edmund Copeland, Edward W. Kolb, Andrew R. Liddle, James E. Lidsey

Generalizing the original work by Hodges and Blumenthal, we outline a formalism which allows one, in principle, to reconstruct the potential of the inflaton field from knowledge of the tensor gravitational wave spectrum or the scalar density fluctuation spectrum, with special emphasis on the importance of the tensor spectrum. We provide some illustrative exa

Scott Dodelson, Lawrence M. Widrow

The simplest model that can accomodate a viable nonbaryonic dark matter candidate is the standard electroweak theory with the addition of right-handed or sterile neutrinos. We reexamine this model and find that the sterile neutrinos can be either hot, warm, or cold dark matter. Since their only direct coupling is to left-handed or active neutrinos, the most

Joseph Polchinski

The normal phase of the high-$T_c$ cuprates is apparently not described by Fermi liquid theory. It has been proposed that a dynamically generated gauge field must appear in the effective field theory. Even a simple spinon-gauge system is complicated, becoming strongly coupled at low energy. We show that in a large-$n$ approximation the theory can be solved a

Stephen Parrott

We argue that purely local experiments can distinguish a stationary charged particle in a static gravitational field from an accelerated particle in (gravity-free) Minkowski space. Some common arguments to the contrary are analyzed and found to rest on a misidentification of ``energy&#39;&#39;.

Abraham Klein, Niels R. Walet

We study the quantum foundations of a theory of large amplitude collective motion for a Hamiltonian expressed in terms of canonical variables. In previous work the separation into slow and fast (collective and non-collective) variables was carried out without the explicit intervention of the Born Oppenheimer approach. The addition of the Born Oppenheimer ass

Feliks Przytycki

We prove that if A is the basin of immediate attraction to a periodic attracting or parabolic point for a rational map f on the Riemann sphere, if $A$ is completely invariant (i.e. $f^{-1}(A)=A$), and if $μ$ is an arbitrary $f$-invariant measure with positive Lyapunov exponents on the boundary of $A$, then $μ$-almost every point $q$ in the boundary of $A$ is

W. M. Koo, H. Saleur

Generalizing the mapping between the Potts model with nearest neighbor interaction and six vertex model, we build a family of &#34;fused Potts models&#34; related to the spin $k/2$ ${\rm U}_{q}{\rm su}(2)$ invariant vertex model and quantum spin chain. These Potts model have still variables taking values $1,\ldots,Q$ ($\sqrt{Q}=q+q^{-1}$) but they have a set

Alan D. Rendall

It is shown that if a representation of a *-algebra on a vector space $V$ is an irreducible *-representation with respect to some inner product on $V$ then under appropriate technical conditions this property determines the inner product uniquely up to a constant factor. Ashtekar has suggested using the condition that a given representation of the algebra of

Frederick J. Ernst, Isidore Hauser

We reformulate the symmetries of Gurses [Phys. Rev. Lett. 70, 367 (1993)] in a more abstract, more geometrical manner. The type (b) transformation of \gurses\ is related to a diffeomorphism of the differentiable manifold onto itself. The type (c) symmetry is replaced by a more general type (c-bar) symmetry that has the nice property that the commutator of a

L. F. Cugliandolo, J. Kurchan

We study the non-equilibrium relaxation of the spherical spin-glass model with p-spin interactions in the $N \rightarrow \infty$ limit. We analytically solve the asymptotics of the magnetization and the correlation and response functions for long but finite times. Even in the thermodynamic limit the system exhibits `weak&#39; (as well as `true&#39;) ergodici

G. Gallavotti, G. Gentile, V. Mastropietro

The parametric equations of KAM tori for a quasi integrable system, are shown to be one point Schwinger functions of a suitable euclidean quantum field theory on the torus. KAM theorem is equivalent to a ultraviolet stability theorem. A renormalization group treatment of the field theory leads to a resummation of the formal pertubation series and to an expan

Emilia Mezzetti

We study the problem of classifying the irreducible projective varieties $X$ of dimension $n\ge 2$ in $\Bbb P^N$ which contain an algebraic family $\Cal F$ of dimension $h+1$ ($h<n$) of subvarieties $Y$ of dimension $n-h$, each one contained in a $\Bbb P^{N-h-1}$. We prove that one of the following happens: (i) there exists an integer $r$, $r<N-n$ such that

Martin White, Lawrence M. Krauss, Joseph Silk

Cosmic Microwave Background (CMB) anisotropies that result from quantum fluctuations during inflation are explored and the impact of their ``cosmic variance&#39;&#39; on the ability to use existing data to probe inflationary models is studied. We calculate the rms temperature fluctuation, and its cosmic variance, for a number of experiments and for models wi

Stefano Forte

We show that in 2+1 dimensional Quantum Electrodynamics an external magnetic field applied to a finite density of massless fermions is screened, due to a $2+1$-dimensional realization of the underlying $2$-dimensional axial anomaly of the space components of the electric current. This is shown to imply screening of the magnetic field, i.e., the Meissner effe

E. Z. Kuchinskii, M. V. Sadovskii

We present the results of theoretical analysis of normal impurities effects in superconductors with the gap being an odd function of k-k_{F}. This model proposed by Mila and Abrahams leads to the possibility of pairing in the presence of arbitrarily strong short-range repulsion between electrons and may be applied to high-Tc oxides.However, we demonstrate th

Fiorenzo Bastianelli, Ulf Lindstrom

We analyze actions for 2D supergravities induced by chiral conformal supermatter. The latter may be thought as described at the classical level by superspace actions invariant under super-reparametrization, super-Weyl and super-Lorentz transformations. Upon quantization various anomalies appear which characterize the non-trivial induced actions for the super

M. D. Freeman, P. West

We review our work on the relation between integrability and infinite-dimensional algebras. We first consider the question of what sets of commuting charges can be constructed from the current of a \mbox{\sf U}(1) Kac-Moody algebra. It emerges that there exists a set $S_n$ of such charges for each positive integer $n>1$; the corresponding value of the centra

Franco Ferrari

We consider here the Chern-Simons field theory with gauge group SU(N) in the presence of a gravitational background that describes a two-dimensional expanding ``universe&#34;. Two special cases are treated here in detail: the spatially flat {\it Robertson-Walker} space-time and the conformally static space-times having a general closed and orientable Riemann

Sumit R. Das

We identify a quantity in the $c=1$ matrix model which describes the wavefunction for physical scattering of a tachyon from a black hole of the two dimensional critical string theory. At the semiclassical level this quantity corresponds to the usual picture of a wave coming in from infinity, part of which enters the black hole becoming singular at the singul

L. Dabrowski, V. K. Dobrev, R. Floreanini, V. Husain

The positive-energy unitary irreducible representations of the $q$-deformed conformal algebra ${\cal C}_q = {\cal U}_q(su(2,2))$ are obtained by appropriate deformation of the classical ones. When the deformation parameter $q$ is $N$-th root of unity, all these unitary representations become finite-dimensional. For this case we discuss in some detail the mas

G. Gat, B. Rosenstein

We show that for collinear processes, i.e. processes where the incoming and outgoing momenta are aligned along the same line, the S-matrix of the tree level 2+1 dimensional Thirring model factorizes: any S - matrix element is a product of $2\rightarrow 2$ elements. In particular this means nullification of all collinear $2 \rightarrow n$ amplitudes for $n >

G. W. Gibbons, R. H. Rietdijk, J. W. van Holten

Spinning particles in curved space-time can have fermionic symmetries generated by the square root of bosonic constants of motion other than the Hamiltonian. We present a general analysis of the conditions under which such new supersymmetries appear, and discuss the Poisson-Dirac algebra of the resulting set of charges, including the conditions of closure of

J. L. Dupont, C. H. Sah

Recently, Rogers&#39; dilogarithm identities have attracted much attention in the setting of conformal field theory as well as lattice model calculations. One of the connecting threads is an identity of Richmond-Szekeres that appeared in the computation of central charges in conformal field theory. We show that the Richmond-Szekeres identity and its extensio

Danny Birmingham, Mark Rakowski

We study the subdivision properties of certain lattice gauge theories based on the groups $Z_{2}$ and $Z_{3}$, in four dimensions. The Boltzmann weights are shown to be invariant under all type $(k,l)$ subdivision moves, at certain discrete values of the coupling parameter. The partition function then provides a combinatorial invariant of the underlying simp

A. Fring, G. Mussardo, P. Simonetti

We derive the recursive equations for the form factors of the local hermitian operators in the Bullough-Dodd model. At the self-dual point of the theory, the form factors of the fundamental field of the Bullough-Dodd model are equal to those of the fundamental field of the Sinh-Gordon model at a specific value of the coupling constant.

M. Micu

The two parameters quantum algebra $SU_{p,k}(2)$ can be obtained from a single parameter algebra $SU_q(2)$. This fact gives some relations between $SU_{p,k}(2)$ quantities and the corresponding ones of the $SU_q(2)$ algebra. In this paper are mentioned the relations concerning: Casimir operators, eigenvectors, matrix elements, Clebsch Gordan coefficients and

Renata Kallosh

In this talk some essential features of stringy black holes are described. We consider charged four-dimensional axion-dilaton black holes. The Hawking temperature and the entropy of all solutions are shown to be simple functions of the squares of supercharges, defining the positivity bounds. Spherically symmetric and multi black hole solutions are presented.

Shinobu Hikami

n-Ising spins on a random surface represented by a matrix model is studied as a model of the 2D gravity coupled to matter field with the central charge c > 1. The magnetic field is introduced to discuss the scaling exponent $Δ$, and the value of this magnetic field exponent is estimated by the series expansion.

T. G. Rizzo

An analysis by the ATLAS Collaboration has recently shown, contrary to popular belief, that a combination of strategic cuts, excellent mass resolution, and detailed knowledge of the QCD backgrounds from direct measurements can be used to extract a signal in the $Z&#39; \to jj$ channel in excess of $6σ$ for certain classes of extended electroweak models. We e

Varun Sahni, Tarun Souradeep

We assess the relative contribution to the COBE - measured microwave anisotropy arising both from relic gravity waves as well as primordial density perturbations originating during inflation. We show that the gravity wave contribution to the CMBR anisotropy depends sensitively upon $n$ -- the primordial spectral index ($\dk^2 \propto k^n$), increasing as $n$