October 1992 arXiv papers — page 3

Itzhak Bars

In this lecture I summarize recent developments on strings propagating in curved spacetime. Exact conformal field theories that describe gravitational backgrounds such as black holes and more intricate gravitational singularities have been discovered and investigated at the classical and quantum level. These models are described by gauged Wess-Zumino-Witten

O. N. Khudaverdian, A. P. Nersessian

Supergeneralization of $\DC P(N)$ provided by even and odd Kählerian structures from Hamiltonian reduction are construct.Operator $ Δ$ which used in Batalin-- Vilkovisky quantization formalism and mechanics which are bi-Hamiltonian under corresponding even and odd Poisson brackets are considered.

M. A. Wisse

The Adler-Kostant-Symes theorem yields isospectral hamiltonian flows on the dual $\tilde\grg^{+*}$ of a Lie subalgebra $\tilde\grg^+$ of a loop algebra $\tilde\grg$. A general approach relating the method of integration of Krichever, Novikov and Dubrovin to such flows is used to obtain finite-gap solutions of matrix Nonlinear Schrödinger Equations in terms o

R. C. Myers, V. Periwal

It is shown that conformal matter with $c_{\ssc L}\not=c_{\ssc R}$ can be consistently coupled to two-dimensional `frame' gravity. The theory is quantized in conformal gauge, following David, and Distler and Kawai. There is no analogue of the $c=1$ barrier found in nonchiral non-critical strings. A non-critical heterotic string is constructed---it has 74

Didier A Depireux, Jeremy Schiff

Recent work on a free field realization of the Hamiltonian structures of the classical KP hierarchy and of its flows is reviewed. It is shown that it corresponds to a reduction of KP to the NLS system. (Talk given by D.A.D. at the NSERC-CAP Workshop on Quantum Groups, Integrable Models and Statistical Systems, Kingston, Canada July 13-17 1992.)

Estia J. Eichten, Ian Hinchliffe, Chris Quigg

Parton distributions derived from a chiral quark model that generates an excess of down quarks and antiquarks in the proton's sea satisfactorily describe the measured yields of muon pairs produced in proton-nucleus collisions. Comparison of dilepton yields from hydrogen and deuterium targets promises greater sensitivity to the predicted flavor asymmetry.

Paul Langacker

The status of proton decay is described, including general motivations for baryon number violation, and the present and future experimental situation. Grand unification with and without supersymmetry is considered, including possible evidence from coupling constant unification and implications for proton decay and neutrino mass.

J. Chýla, J. Fischer, P. Kolář

A recently proposed method of estimating the asymptotic behaviour of QCD perturbation theory coefficients is critically reviewed and shown to contain numerous invalid mathematical operations and unsubstantiated assumptions. We discuss in detail why this procedure, based solely on renormalization group (RG) considerations and analyticity constraints, cannot l

Ralf Hecht, Friedrich W. Hehl, J. Dermott McCrea, Eckehard W. Mielke

In Minkowski spacetime it is well-known that the canonical energy-momentum current is involved in the construction of the globally conserved currents of energy-momentum and total angular momentum. For the construction of conserved currents corresponding to (approximate) scale and proper conformal symmetries, however, an improved energy-momentum current is ne

Johannes Kellendonk

\noindent The algebraic characterization of classes of locally isomorphic aperiodic tilings, being examples of quantum spaces, is conducted for a certain type of tilings in a manner proposed by A. Connes. These $2$-dimensional tilings are obtained by application of the strip method to the root lattice of an $ADE$-Coxeter group. The plane along which the stri

Benjamin Grinstein

Talk presented at the Trieste Workshop on the Search for New Elementary Particles: Status and Prospects.

Eugene Lerman, Reyer Sjamaar

We prove that the action of a reductive complex Lie group on a Kähler manifold can be linearized in the neighbourhood of a fixed point, provided that the restriction of the action to some compact real form of the group is Hamiltonian with respect to the Kähler form.

M. Billo', P. Fre', L. Girardello, A. Zaffaroni

We study the problem of string propagation in a general instanton background for the case of the complete heterotic superstring. We define the concept of generalized HyperK\" ahler manifolds and we relate it to (4,4) superconformal theories. We propose a generalized h-map construction that predicts a universal SU(6) symmetry for the modes of the string e

A. T. Filippov, A. P. Isaev, A. B. Kurdikov

Explicit general constructions of paragrassmann calculus with one and many variables are given. Relations of the paragrassmann calculus to quantum groups are outlined and possible physics applications are briefly discussed. This paper is the same as the original 9210075 except added Appendix and minor changes in Acknowledgements and References. IMPORTANT NOT

J. Harnad, M. -A. Wisse

The sine-Gordon equation is considered in the hamiltonian framework provided by the Adler-Kostant-Symes theorem. The phase space, a finite dimensional coadjoint orbit in the dual space $\grg^*$ of a loop algebra $\grg$, is parametrized by a finite dimensional symplectic vector space $W$ embedded into $\grg^*$ by a moment map. Real quasiperiodic solutions are

Craig A. Tracy, Harold Widom

Scaling level-spacing distribution functions in the ``bulk of the spectrum'' in random matrix models of $N\times N$ hermitian matrices and then going to the limit $N\to\infty$, leads to the Fredholm determinant of the sine kernel $\sinπ(x-y)/π(x-y)$. Similarly a double scaling limit at the ``edge of the spectrum'' leads to the Airy kernel $[{

Craig A. Tracy, Harold Widom

These notes provide an introduction to the theory of random matrices. The central quantity studied is $τ(a)= det(1-K)$ where $K$ is the integral operator with kernel $1/π} {\sinπ(x-y)\over x-y} χ_I(y)$. Here $I=\bigcup_j(a_{2j-1},a_{2j})$ and $χ_I(y)$ is the characteristic function of the set $I$. In the Gaussian Unitary Ensemble (GUE) the probability that n

S. Kharchev, A. Marshakov

We discuss the non--perturbative formulation for $c \leq 1$ string theory. The field theory like formulation of topological and non--topological models is presented. The integral representation for arbitrary $(p,q)$ solutions is derived which explicitly obeys $p-q$ duality of these theories. The exact solutions to string equation and various examples are als

Paul Langacker, Nir Polonsky

The status of coupling constant unification in the standard model and its supersymmetric extension are discussed. Uncertainties associated with the input coupling constants, $m_{t}$, threshold corrections at the low and high scales, and possible nonrenormalizable operators are parametrized and estimated. A simple parametrization of a general supersymmetric n

F. Cooper, H. Shepard, C Lucheroni, P. Sodano

Gaussians to study soliton behavior and blowup in the nonlinear Schrodinger equation in arbitrary dimension d and with arbitrary nonlinearity parameter kappa

J. Greensite

It is suggested that not only the curvature, but also the signature of spacetime is subject to quantum fluctuations. A generalized D-dimensional spacetime metric of the form $g_{μν}=e^a_μη_{ab} e^b_ν$ is introduced, where $η_{ab} = diag\{e^{iθ},1,...,1\}$. The corresponding functional integral for quantized fields then interpolates from a Euclidean path inte

L. Bergomi, J. P. Blaizot, Th. Jolicoeur, E. Dagotto

The one-band Hubbard model at half-filling on a truncated tetrahedron (C$_{12}$), and on the C$_{60}$ molecule is studied. Within the Hartree-Fock approximation, we find a magnetic-like instability of the `Fermi sea' towards a spin-ordered phase for an intermediate value of the coupling ${\rm (U/t)_c}\approx 2.6$. The ordered phase presents a spin arrang

Kikuo Harigaya, Mitsutaka Fujita

Possible dimerization patterns and electronic structures in fullerene tubules as the one-dimensional pi-conjugated systems are studied with the extended Su-Schrieffer-Heeger model. We assume various lattice geometries, including helical and nonhelical tubules. The model is solved for the half-filling case of $π$-electrons. (1) When the undimerized systems do

Fong Liu, Gene F. Mazenko

The order parameter correlation function of the nonconserved, continuum $q$-state clock model is evaluated in the asymptotic scaling limit, during the phase ordering process after a temperature quench. The short distance behavior of the order parameter scaling function exhibits explicit crossover from that characteristic of the Ising universality class to th

Ajit Mohan Srivastava

We analyze the core structure of string defects in various condensed matter systems, such as nematic liquid crystals and superfluid helium, and argue that in certain cases the variation of the refractive index near the core is such that it can lead to total internal reflection of light travelling along the string core. These strings thus behave as optical fi

S. Cristiani, E. Giallongo, L. M. Buson, C. Gouiffes

The average flux decrement shortward the Ly$_α$ emission, due to the well-known ``forest'' of absorptions, has been measured in the spectra of 8 quasars. Quasi-simultaneous optical and IUE observations of the two low redshift quasars PKS 0637--75 (z=0.654) and MC 1104+16 (z=0.632) have been carried out, obtaining relatively high S/N, spectrophotometr

Christopher T. Hill, Dallas C. Kennedy, Tetsuya Onogi, Hoi--Lai Yu

We propose spontaneously breaking technicolor, thus liberating techniquarks and suppressing large resonance contributions to the electroweak $S$ parameter. The dynamics is modeled by a fermion bubble approximation to a single massive techni--gluon exchange potential. This contains a Nambu--Jona-Lasinio model with additional interactions. ``Virtual''

Jonathan A. Bagger

In this talk we survey the SSC signals and backgrounds for the physics of electroweak symmetry breaking. We study the process $pp \rightarrow WWX$ and compute the rate for the ``gold-plated'' signals $W^\pm \rightarrow \ell^\pm ν$ and $Z \rightarrow \ell^+\ell^-$ $(\ell = e,μ)$ for a wide variety of models. We use a forward jet tag and central jet ve

Arlen Anderson

Recent work on canonical transformations in quantum mechanics is applied to transform between the Moncrief metric formulation and the Witten-Carlip holonomy formulation of 2+1-dimensional quantum gravity on the torus. A non-polynomial factor ordering of the classical canonical transformation between the metric and holonomy variables is constructed which pres

James B. Hartle

A pedagogical introduction is given to the quantum mechanics of closed systems, most generally the universe as a whole. Quantum mechanics aims at predicting the probabilities of alternative coarse-grained time histories of a closed system. Not every set of alternative coarse-grained histories that can be described may be consistently assigned probabilities b

F. Sammarruca, D. P. Xu, R. Machleidt

The influence of relativity on the triton binding energy is investigated. The relativistic three-dimensional version of the Bethe-Salpeter equation proposed by Blankenbecler and Sugar (BbS) is used. Relativistic (non-separable) one-boson-exchange potentials (constructed in the BbS framework) are employed for the two-nucleon interaction. In a 34-channel Fadde

J. Harnad, M. -. Wisse

It is shown how Darboux coordinates on a reduced symplectic vector space may be used to parametrize the phase space on which the finite gap solutions of matrix nonlinear Schrödinger equations are realized as isospectral Hamiltonian flows. The parametrization follows from a moment map embedding of the symplectic vector space, reduced by suitable group actions

R. Ferraro, M. Henneaux, M. Puchin

Reducible gauge theories with constraints linear in the momenta are quantized. The equivalence of the reduced phase space quantization, Dirac quantization and BRST quantization is established. The ghosts of ghosts are found to play a crucial role in the equivalence proof.

Jouko Mickelsson

It is proposed that instead of normal representations one should look at cocycles of group extensions valued in certain groups of unitary operators acting in a Hilbert space (e.g the Fock space of chiral fermions), when dealing with groups associated to current algebras in gauge theories in $3+1$ space-time dimensions. The appropriate cocycle is evaluated in

B. de Wit, F. Vanderseypen, A. Van Proeyen

Using techniques from supergravity and dimensional reduction, we study the full isometry algebra of Kähler and quaternionic manifolds with special geometry. These two varieties are related by the so-called c-map, which can be understood from dimensional reduction of supergravity theories or by changing chirality assignments in the underlying superstring theo

J. Hietarinta

We describe how the complete solution to the two-dimensional constant quantum Yang-Baxter equation [J. Hietarinta, Phys. Lett. A165,245(1992)] was found. (Talk presented at the XIX International Colloquium on Group Theoretical Methods in Physics.)

L. Randall

We consider constraints on models in which a top quark mass is generated through unenhanced extended technicolor interactions. The deviation in the $ρ$ parameter from unity and $B$--$\overline{B}$ mixing could be large, but given the uncertainties in strong dynamics and variations in the parameters of models, no conclusive statement can be given. We conclude

L. Randall

We construct an extended technicolor model of quarks and leptons which preserves a GIM mechanism. Furthermore, there is only a minimal technicolor sector, in accordance with recent precision measurements of electroweak parameters. We also show how to incorporate custodial SU(2) and massless neutrinos into such a model.

Gupta, Daniel, Kilcup, Patel

We calculate the kaon $B$-parameter in quenched lattice QCD at $β=6.0$ using Wilson fermions at $κ=0.154$ and $0.155$. We use two kinds of non-local (``smeared'') sources for quark propagators to calculate the matrix elements between states of definite momentum. The use of smeared sources yields results with much smaller errors than obtained in previ

R. Kenna, C. B. Lang

The leading mean-field critical behaviour of $ϕ^4_4$-theory is modified by multiplicative logarithmic corrections. We analyse these corrections both analytically and numerically. In particular we present a finite-size scaling theory for the Lee-Yang zeroes and temperature zeroes, both of which exhibit logarithmic corrections. On lattices from size $8^4$ to $

Olivier Debarre

The degree of a curve $C$ in a polarized abelian variety $(X,λ)$ is the integer $d=C\cdotλ$. When $C$ generates $X$, we find a lower bound on $d$ which depends on $n$ and the degree of the polarization $λ$. The smallest possible degree is $d=n$ and is obtained only for a smooth curve in its Jacobian with its principal polarization (Ran, Collino). The cases $

Olivier Debarre, Matthew Klassen

The purpose of this note is to provide some applications of Faltings' recent proof of S. Lang's conjecture to smooth plane curves. Let $C$ be a smooth plane curve defined by an equation of degree $d$ with integral coefficients. We show that for $d\ge 7$, the curve $C$ has only finitely many points whose field of definition has degree $\le d-2$ over $

T. Hollowood, J. L. Miramontes, J. Sanchez Guillen

We review the construction of generalized integrable hierarchies of partial differential equations, associated to affine Kac-Moody algebras, that include those considered by Drinfel'd and Sokolov. These hierarchies can be used to construct new models of 2D quantum or topological gravity, as well as new $\cal W$-algebras.

Yas-hiro Quano, Akira Fujii

We construct a factorized representation of the $\frak g \frak l _n$-Sklyanin algebra from the vertex-face correspondence. Using this representation, we obtain a new solvable model which gives an $\frak s \frak l _n$-generalization of the broken $\bz _N $ model. We further prove the Yang-Baxter equation for this model.

G. E. Brown, R. Machleidt

Once density-dependent meson masses are introduced into the nuclear many-body problem, conventional mechanisms for saturation no longer operate. We suggest that a loop correction, essentially the introduction of the axial vector coupling $g_A(ρ,k)$ as function of density $ρ$ and momentum $k$, can bring about saturation, and present schematic calculations to

Paolo M. Gensini

A chapter to be included in "The DA$\mitΦ$NE Physics Handbook" by the DA$Φ$NE Theory Working Group, this paper covers the phenomenology of low--energy $K N$ physics, with particular emphasis on the problems still to be solved by a careful experimental investigation and on the theoretical tools to analyse it.

Paolo M. Gensini

The paper is the written version of a talk presented at the "VIIth Winter School of Hadronic Physics", held in Folgaria (Trento), Italy, February 10--15, 1992. We intend to illustrate in this lecture the possibilities opening up at machines planned for the nineties for low--energy kaon--nucleon interactions, keeping the focus on the theoretical probl

Paolo M. Gensini, Galileo Violini

We survey the open problems in low--energy $KN$ physics, in the perspective of using the new machines presently planned, such as the $ϕ$--factory DA$Φ$NE at I.N.F.N. Nat. Labs. in Frascati (as a source of {\sl tagged}, low--energy kaons) and the KAON Factory at TRIUMF (as a producer of intense, intermediate--energy kaon beams).

M. K. Liou, Dahang Lin, B. F. Gibson

A modified Low procedure for constructing soft-photon amplitudes has been used to derive two general soft-photon amplitudes, a two-s-two-t special amplitude $M^{TsTts}_μ$ and a two-u-two-t special amplitude $M^{TuTts}_μ$, where s, t and u are the Mandelstam variables. $M^{TsTts}_μ$ depends only on the elastic T-matrix evaluated at four sets of (s,t) fixed by

Edward Witten

Recently, background independent open-string field theory has been formally defined in the space of all two-dimensional world-sheet theories. In this paper, to make the construction more concrete, I compute the action for an off-shell tachyon field of a certain simple type. From the computation it emerges that, although the string field action does not coinc

Keith R. Dienes

Fractional superstrings are non-trivial generalizations of ordinary superstrings and heterotic strings, and have critical spacetime dimensions which are less than ten by virtue of a worldsheet fractional supersymmetry relating worldsheet bosons to worldsheet parafermions. In this paper, I provide a short non-technical survey of the fundamental issues involve

Rolf Schimmrigk

A new framework is found for the compactification of supersymmetric string theory. It is shown that the massless spectra of Calabi--Yau manifolds of complex dimension $D_{crit}$ can be derived from noncritical manifolds of complex dimension $2k + D_{crit}$, $k\geq 1$. These higher dimensional manifolds are spaces whose nonzero Ricci curvature is quantized in

Masako Bando, Taichiro Kugo, Nobuhiro Maekawa, Hiroaki Nakano

Previously proposed procedure for improving the effective potential by using renormalization group equation (RGE) is generalized so as to be applicable to any system containing several different mass scales. If one knows L-loop effective potential and (L+1)-loop RGE coefficient functions, this procedure gives an improved potential which satisfies the RGE and

Masako Bando, Taichiro Kugo, Nobuhiro Maekawa, Hiroaki Nakano

A general procedure is presented how to improve the effective potential by using the renormalization group equation (RGE) in MS bar scheme. If one knows the L-loop effective potential and the RGE coefficient functions up to (L+1)-loop level, this procedure gives an improved potential which satisfies the RGE and contains all of the leading, next-to-leading,..

R. Percacci, E. Sezgin

Using canonical methods, we study the invariance properties of a bosonic $p$--brane propagating in a curved background locally diffeomorphic to $M\times G$, where $M$ is spacetime and $G$ a group manifold. The action is that of a gauged sigma model in $p+1$ dimensions coupled to a Yang--Mills field and a $(p+1)$--form in $M$. We construct the generators of Y

T. Curtright, C. Zachos

In the quantized two-dimensional non-linear supersymmetric $σ$-model, the supercurrent supermultiplet, which contains the energy-momentum tensor, is transformed by the nonlocal symmetry of the model into the isospin current supermultiplet. This effect incorporates supersymmetry into the known infinite-dimensional Yangian deformation symmetry of plain $σ$-mod

A. Houghton, J. B. Marston

(Revised, with postscript figures appended, corrections and added comments.) We develop and describe new approaches to the problem of interacting Fermions in spatial dimensions greater than one. These approaches are based on generalizations of powerful tools previously applied to problems in one spatial dimension. We begin with a review of one-dimensional in

Christopher Golé

This paper concentrates on optical Hamiltonian systems of $T*\T^n$, i.e. those for which $\Hpp$ is a positive definite matrix, and their relationship with symplectic twist maps. We present theorems of decomposition by symplectic twist maps and existence of periodic orbits for these systems. The novelty of these results resides in the fact that no explicit as

S. Bellucci, E. Ivanov, S. Krivonos

We construct a one-parameter family of N=3 supersymmetric extensions of the KdV equation as a Hamiltonian flow on N=3 superconformal algebra and argue that it is non-integrable for any choice of the parameter. Then we propose a modified N=3 super KdV equation which possesses the higher order conserved quantities and so is a candidate for an integrable system

E. Ivanov, S. Krivonos, R. P. Malik

We construct new coset realizations of infinite-dimensional linear $W_3^{\infty}$ symmetry associated with Zamolodchikov's $W_3$ algebra which are different from the previously explored $sl_3$ Toda realization of $W_3^{\infty}$. We deduce the Boussinesq and modified Boussinesq equations as constraints on the geometry of the corresponding coset manifolds.

Sangyong Jeon

Convenient Cutkosky-like diagrammatic rules for computing the spectral densities of arbitrary two-point correlation functions in finite temperature field theory are derived. The approach is based on an explicit analytic continuation of imaginary-time Feynman diagrams and avoids the complications of real-time finite temperature perturbation theory. The applic

Tetsuya Hattori, Hideo Nakajima

A method for generating random $U(1)$ variables with Boltzmann distribution is presented. It is based on the rejection method with transformation of variables. High efficiency is achieved for all range of temparatures or coupling parameters, which makes the present method especially suitable for parallel and pipeline vector processing machines. Results of co

Andrej Tyurin

The simplest version of the Spin-polynomial invariants of the underlying differentiable structures of algebraic surfaces were considered and the simplest arguments were used in order to distinguish the underlying smooth structures of certain algebraic surfaces.

Victor M. Yakovenko

Renormalization group equations and a phase diagram are derived for a system of two chains with a single-electron hopping between chains in order to correct the results of a recent paper by F.~V.~Kusmartsev, A.~Luther, and A.~Nersesyan, Pis'ma v Zh.\ Exp.\ Teor.\ Fiz.\ {\bf 55}, 692 (1992) [JETP Lett.\ {\bf 55}, 724 (1992)].

Gideon Lana, Benjamin Svetitsky

The small surface tension of the interface between hadronic and quark-gluon-plasma domains, along with a negative curvature tension, implies that the uniform plasma is unstable against spontaneous formation of hadronic bubbles. We furthermore show that spherical bubbles are not stable against small perturbations.

Fedor A. Smirnov

We study the limit of asymptotically free massive integrable models in which the algebra of nonlocal charges turns into affine algebra. The form factors of fields in that limit are described by KZ equations on level 0. We show the limit to be connected with finite-gap integration of classical integrable equations.

Fedor A. Smirnov

Deformed and undeformed KZ equations are considered for $k=0$. It is shown that they allow the same number of solutions, one being the asymptotics of others. Essential difference in analitical properties of the solutions is explained.

Makoto Sakamoto

We study string theory on orbifolds in the presence of an antisymmetric constant background field and discuss some of new aspects of the theory. It is shown that the term with the antisymmetric field has a topological nature like a Chern-Simons term or a Wess-Zumino term. Due to this property, the theory exhibits various anomalous behavior: Zero mode variabl

H. J. de Vega

We report on a new approach to the calculation of thermodynamic functions for crossing-invariant models solvable by Bethe Ansatz. In the case of the XXZ Heisenberg chain we derive, for arbitrary values of the anysotropy, a single non-linear integral equation from which the free energy can be exactly calculated.These equations are shown to be equivalent to an

G. A. Diamandis, B. C. Georgalas, X. Maintas, N. E. Mavromatos

We discuss time-dependent perturbations (induced by matter fields) of a black-hole background in tree-level two-dimensional string theory. We analyse the linearized case and show the possibility of having black-hole solutions with time-dependent horizons. The latter exist only in the presence of time-dependent `tachyon' matter fields, which constitute th

Bo-Sture K Skagerstam

The components of the position operator, at a fixed time, for a massless and spinning particle with given helicity $λ$ described in terms of bosonic degrees of freedom have an anomalous commutator proportional to $λ$. The position operator generates translations in momentum space. We show that a ray-representation for these translations emerges due to the no

Jürgen Fuchs, Maximilian Kreuzer

We search for a \Lg\ interpretation of non-diagonal modular invariants of tensor products of minimal $n=2$ superconformal models, looking in particular at automorphism invariants and at some exceptional cases. For the former we find a simple description as \lgo s, which reproduce the correct chiral rings as well as the spectra of various Gepner--type models

Ashoke Sen

In this review, I discuss a general method for constructing classical solutions of the equations of motion arising in the effective low energy string theory, and discuss specific applications of this method. (Based on talks given at the Johns Hopkins Workshop held at Goteborg, June 8-10, 1992, and ICTP Summer Workshop held at Trieste, July 2-3, 1992)

Paul H. Frampton, James T. Liu

Superstrings have been postulated based on parafermionic partition functions which permit spacetime supersymmetry by generalized Jacobi identities. A comprehensive search finds new such identities. Quadrilateral anomaly cancellation gives constraints on allowed chiral fermions. Bosonic left-movers and $Z_4$ parafermionic right-movers combine in a new heterot

Hyun Kyu Lee, Mannque Rho

We study the role of rotational symmetry in the systems where nonabelian Berry potentials emerge as a result of integrating out fast degrees of freedom. The conserved angular momentum is constructed in the presence of a non-abelian Berry potential, which is formulated using Grassmann variables. The modifications on conventional angular momentum are discussed

F. Cooper, C. Lucheroni, H. Shepard, P. Sodano

We use a class of trial wave functions which are generalizations of gaussians to study single soliton approximate analytic solutions to the KdV equations. The variational parameters obey a Hamiltonian dynamics obtained from the Principle of Least Action. We get extremely accurate approximate single soliton solutions including their time dependence using this

K. Tsushima, D. O. Riska

We show that the predicted hyperon masses in the topological soliton model are very sensitive to the value of the gluon condensate parameter that appears when the scale invariance and trace anomaly of QCD are taken into account by introduction of a dilaton field. This contrasts with the insensitivity of the soliton properties to the dilaton coupling. In orde

J. Choi, R. R. Volkas

We obtain the effective potential at finite temperature within the left-right symmetric model. We take the Higgs sector to consist of two doublets and calculate its finite temperature effective potential up to the order of ``ring-diagrams'', using analogous techniques to those employed in the derivation of the effective potential in the Standard Mode

Mp Lombardo, J. B. Kogut, A. Kocic, K. C. Wang

We review the results of large scale simulations of noncompact quenched $QED$ which use spectrum and Equation of State calculations to determine the theory's phase diagram, critical indices, and continuum limit. The resulting anomalous dimensions are in good agreement with Schwinger-Dyson solutions of the ladder graphs of conventional $QED$ and they sati

Alonso, Azcoiti, Campos, Ciria

We study numerically the critical properties of the U(1)-Higgs lattice model, with fixed Higgs modulus, in the region of small gauge coupling where the Higgs and Confining phases merge. We find evidence of a first order transition line that ends in a second order point. By means of a rotation in parameter space we introduce thermodynamic magnitudes and criti

Michael Dine

This talk considers possible lessons of string theory for low energy physics. These are of two types. First, assuming that string theory is the correct underlying theory of all interactions, we ask whether there are any generic predictions the theory makes, and we compare the predictions of string theory with those of conventional grand unified theories. Sec

Joseph Polchinski

This is an introduction to the method of effective field theory. As an application, I derive the effective field theory of low energy excitations in a conductor, the Landau theory of Fermi liquids, and explain why the high-$T_c$ superconductors must be described by a different effective field theory.

Shahn Majid

We introduce $*$-structures on braided groups and braided matrices. Using this, we show that the quantum double $D(U_q(su_2))$ can be viewed as the quantum algebra of observables of a quantum particle moving on a hyperboloid in q-Minkowski space (a three-sphere in the Lorentz metric), and with the role of angular momentum played by $U_q(su_2)$. This provides

W. Eholzer

Using the representation theory of the subgroups SL_2(Z_p) of the modular group we investigate the induced fusion algebras in some simple examples. Only some of these representations lead to 'good' fusion algebras. Furthermore, the conformal dimensions and the central charge of the corresponding rational conformal field theories are calculated. Two s

L. Feher, John Harnad, I. Marshall

Generalized Drinfeld-Sokolov (DS) hierarchies are constructed through local reductions of Hamiltonian flows generated by monodromy invariants on the dual of a loop algebra. Following earlier work of De Groot et al, reductions based upon graded regular elements of arbitrary Heisenberg subalgebras are considered. We show that, in the case of the nontwisted loo

I. R. Afnan, B. F. Gibson

Using separable $NN$ and $ΛN$-$ΣN$ potentials in the Faddeev equations, we have demonstrated that the predicted enhancement in the $Λd$ cross section near the $Σd$ threshold is associated with resonance poles in the scattering amplitude. The positions of these poles, on the second Riemann sheet of the complex energy plane, are determined by examining the eig

Michael Cwikel, Nigel J. Kalton

Let $ X=(X_0,X_1)$ and $ Y=(Y_0,Y_1)$ be Banach couples and suppose $T: X\to Y$ is a linear operator such that $T:X_0\to Y_0$ is compact. We consider the question whether the operator $T:[X_0,X_1]_θ\to [Y_0,Y_1]_θ$ is compact and show a positive answer under a variety of conditions. For example it suffices that $X_0$ be a UMD-space or that $X_0$ is reflexive

Haskell P. Rosenthal

A subsequence principle is obtained, characterizing Banach spaces containing $c_0$, in the spirit of the author's 1974 characterization of Banach spaces containing $\ell^1$. Definition: A sequence $(b_j)$ in a Banach space is called {\it strongly summing\/} (s.s.) if $(b_j)$ is a weak-Cauchy basic sequence so that whenever scalars $(c_j)$ satisfy $\sup_n

Joseph Polchinski

Is large-$N$ QCD equivalent to a string theory? Maybe, maybe not. I review various attempts to answer the question.

T. Tjin

By generalizing the Drinfeld-Sokolov reduction a large class of $W$ algebras can be constructed. We introduce 'finite' versions of these algebras by Poisson reducing Kirillov Poisson structures on simple Lie algebras. A closed and coordinate free formula for the reduced Poisson structure is given. These finitely generated algebras play the same role

W. K. Baskerville, S. Majid

We compute the braided groups and braided matrices $B(R)$ for the solution $R$ of the Yang-Baxter equation associated to the quantum Heisenberg group. We also show that a particular extension of the quantum Heisenberg group is dual to the Heisenberg universal enveloping algebra $U_{q}(h)$, and use this result to derive an action of $U_{q}(h)$ on the braided

J. Sonnenschein

Recent results about topological coset models are summarized. The action of a topological ${G\over H}$ coset model ($rank\ H = rank\ G$) is written down as a sum of ``decoupled" matter, gauge and ghost sectors. The physical states are in the cohomology of a BRST-like operator that relates these secotrs. The cohomology on a free field Fock space as well a

T. Fujiwara, Y. Igarashi, J. Kubo, K. Maeda

Using the generalized hamiltonian method of Batalin, Fradkin and Vilkovisky, we investigate the algebraic structure of anomalies in the Polyakov string theory that appear as the Schwinger terms in super-commutation relations between BRST charge and total hamiltonian. We obtain the most general form of the anomalies in the extended phase space, without any re

Mirjam Cvetic, Paul Langacker

We discuss three promising diagnostic probes of the couplings of a possible heavy $Z'$ boson at hadron colliders: the forward-backward asymmetry into leptons, the rare decay $Z' \ra W^{\pm} \ell^{\mp} ν$, and associated production $pp \ra Z'W,\; Z'Z$. A general model-independent framework is proposed for interpreting these and other data. Cle

Lawrence M. Krauss, Evalyn Gates, Martin White

We incorporate all existing solar neutrino flux measurements and take solar model flux uncertainties into account in deriving global fits to parameter space for the MSW and vacuum solutions of the solar neutrino problem.

A. Wirzba

We show that color can leak from a QCD bag if we allow for pseudoscalar isoscalar singlet ($η'$) coupling at the surface. To enforce total confinement of color an additional boundary term is suggested. New relations between the $η'$ mass and decay constant and the QCD gluon condensates are derived and compared with the empirical parameters.

T. DeGrand, M. Hecht

We describe the calculation of Coulomb gauge wave functions for light quark systems, and their use as interpolating fields for excited state spectroscopy.

Massimo Campostrini, Paolo Rossi, Ettore Vicari

We investigate the features of ${\rm CP}^{N-1}$ models concerning confinement and topology. In order to study the approach to the large-$N$ asymptotic regime, we determine the topological susceptibility and the string tension for a wide range of values of $N$, in particular $N=4,10,21,41$. Quantitative agreement with the large-$N$ predictions is found for th

Massimo Campostrini, Paolo Rossi

The main technical and conceptual features of the lattice $1/N$ expansion in the scaling region are discussed in the context of a two-parameter two-dimensional spin model interpolating between $CP^{N-1}$ and $O(2N)$ $σ$ models, with standard and improved lattice actions. We show how to perform the asymptotic expansion of effective propagators for small value

Massimo Campostrini, Paolo Rossi, Ettore Vicari

Two-dimensional $CP^{N-1}$ models are investigated by Monte Carlo methods on the lattice, for values of $N$ ranging from 2 to 21. Scaling and rotation invariance are studied by comparing different definitions of correlation length $ξ$. Several lattice formulations are compared and shown to enjoy scaling for $ξ$ as small as $2.5$. Asymptotic scaling is invest