arXiv papers from April 1992

Daniel Kabat

We summarize results on the reliability of the eikonal approximation in obtaining the high energy behavior of a two particle forward scattering amplitude. Reliability depends on the spin of the exchanged field. For scalar fields the eikonal fails at eighth order in perturbation theory, when it misses the leading behavior of the exchange-type diagrams. In a v

Sergio Cecotti, Paul Fendley, Ken Intriligator, Cumrun Vafa

We show that ${\rm Tr}(-1)^F F e^{-\beta H}$ is an index for $N$=2 supersymmetric theories in two dimensions, in the sense that it is independent of almost all deformations of the theory. This index is related to the geometry of the vacua (Berry's curvature) and satisfies an exact differential equation as a function of $\beta$. For integrable theories we can

D. J. Johnson, M. W. Friedlander, J. I. Katz

Dust is observed to form in nova ejecta. The grain temperature is determined by the diluted nova radiation field rather than the gas kinetic temperature, making classical nucleation theory inapplicable. We used kinetic equations to calculate the growth of carbon nuclei in these ejecta. For expected values of the parameters too many clusters grew, despite the

B P Schmidt, R P Kirshner, R G Eastman

We use the Expanding Photosphere Method to determine distances to 10 type II supernovae. The effects of asymmetries, extinction, and flux dilution are explored. Using empirical evidence and time-independent, spherical models which treat H and He in non-LTE, we show that blackbody corrections caused by flux dilution are small for type II supernovae in the inf

B. J. Carrigan, J. I. Katz

We have calculated gamma-ray radiative transport in regions of high energy density, such as gamma-ray burst source regions, using a discrete ordinate, discrete energy group method. The calculations include two-photon pair production and annihilation, as well as three-photon pair annihilation. The radiation field itself acts as an absorbing medium, and the op

K. Haglin, C. Gale, V. Emel'yanov

A soft photon approximation is used to calculate the rates of lepton pair production through virtual bremsstrahlung from both pions and quarks. Standard assumptions about the evolution of a nuclear system under collision allow pion and quark driven total production to be calculated. Comparisons are made with Dalitz decay of light mesons. These mechanisms are

Daniel Cangemi, Choonkyu Lee

We consider here a generalization of the Abelian Higgs model in curved space, by adding a Chern--Simons term. The static equations are self-dual provided we choose a suitable potential. The solutions give a self-dual Maxwell--Chern--Simons soliton that possesses a mass and a spin.

Theodore C. Hsu

The response of a single vortex to a time dependent field is examined microscopically and an equation of motion for vortex motion at non-zero frequencies is derived. Of interest are frequencies near $\Delta^{2}/E_{F}$, where $\Delta$ is the bulk energy gap and $E_{F}$ is the fermi energy. The low temperature, clean, extreme type II limit and maintaining of e

M. Grabenstein, K. Pinn

An approximation formula is derived for acceptance rates of nonlocal Metropolis updates in simulations of lattice field theories. The predictions of the formula agree quite well with Monte Carlo simulations of 2-dimensional Sine Gordon, XY and phi**4 models. The results are consistent with the following rule: For a critical model with a fundamental Hamiltoni

Elizabeth Jenkins, Michael Luke, Aneesh V. Manohar, Martin J. Savage

Semileptonic decay of the $B_c$ meson is studied in the heavy quark limit. The six possible form factors for $B_c \rightarrow B_s (B^0),B_s^* (B^{*0})$ semileptonic decay are determined by two invariant functions. Only one of these functions contributes at zero recoil, where it is calculable to lowest order in an operator product expansion in terms of the me

Máximo Bañados, Claudio Teitelboim, Jorge Zanelli

The standard Einstein-Maxwell equations in 2+1 spacetime dimensions, with a negative cosmological constant, admit a black hole solution. The 2+1 black hole -characterized by mass, angular momentum and charge, defined by flux integrals at infinity- is quite similar to its 3+1 counterpart. Anti-de Sitter space appears as a negative energy state separated by a

Z. Maassarani, D. Nemeschansky, N. P. Warner

We obtain lattice models whose continuum limits correspond to $N=2$ superconformal coset models. This is done by taking the well known vertex model whose continuum limit is the $G \times G/G$ conformal field theory, and twisting the transfer matrix and modifying the quantum group truncation. We find that the natural order parameters of the new models are pre

A. Kent

We use recently derived explicit formulae for the Virasoro algebra's singular vectors to give constructive proofs of three results due to Feigin and Fuchs. The main result, which is needed for a rigorous treatment of fusion, describes the action of the singular vectors on conformal fields.

A. Kent

We give expressions for the singular vectors in the highest weight representations of the Virasoro algebra. We verify that the expressions --- which take the form of a product of operators applied to the highest weight vector --- do indeed define singular vectors. These results explain the patterns of embeddings amongst Virasoro algebra highest weight repres

T. Banks, A. Dabholkar

Perturbative analyses seem to suggest that fermions whose mass comes solely from a Yukawa coupling to a scalar field can be made arbitrarily heavy, while the scalar remains light. The effects of the fermion can be summarized by a local effective Lagrangian for the light degrees of freedom. Using weak coupling and large N techniques, we present a variety of m

Peter Cho, Benjamin Grinstein

First order power corrections to current matrix elements between heavy meson or $\Lambda_\Q$ baryon states are shown to vanish at the zero recoil point to all orders in QCD. Five relations among the six form factors that parametrize the semileptonic decay $\Lambda_b \to \Lambda_c e \overline{\nu}$ are also demonstrated to exist to all orders in the strong co

J. I. Katz

The BATSE experiment on GRO has demonstrated the isotropic arrival directions and flat $\log N$ {\it vs.} $\log S$ of cosmic gamma-ray bursts. These data are best explained if the burst sources are distributed throughout an extended spherical Galactic halo, as previously suggested by Jennings. The halo's radius is at least 40 Kpc, and probably is more than 1

V. Koch, E. V. Shuryak, G. E. Brown, A. D. Jackson

The dynamics of {\it light} fermions propagating in a spatial direction at high temperatures can be described effectively by a two--dimensional Schr\"odinger equation with {\it heavy} effective mass $m_{\rm eff} = \pi T$. Starting from QED, we discuss the transition from three-- to two--dimensional positronium discussing the latter in detail including relati

John Ellis, N. E. Mavromatos, D. V. Nanopoulos

We argue that the infinitely many gauge symmetries of string theory provide an infinite set of conserved (gauge) quantum numbers (W-hair) which characterise black hole states and maintain quantum coherence, even during exotic processes like black hole evaporation/decay. We study ways of measuring the W-hair of spherically-symmetric four-dimensional objects w

O. Aharony, O. Ganor, N. Sochen J. Sonnenschein, S. Yankielowicz

An analysis of the BRST cohomology of the G/G topological models is performed for the case of $A_1^{(1)}$. Invoking a special free field parametrization of the various currents, the cohomology on the corresponding Fock space is extracted. We employ the singular vector structure and fusion rules to translate the latter into the cohomology on the space of irre

P. Fendley, H. Saleur

We discuss in this paper various aspects of the off-critical $O(n)$ model in two dimensions. We find the ground-state energy conjectured by Zamolodchikov for the unitary minimal models, and extend the result to some non-unitary minimal cases. We apply our results to the discussion of scaling functions for polymers on a cylinder. We show, using the underlying

Z. N. C. Ha, F. D. M. Haldane

A one-dimensional quantum N-body system of either fermions or bosons with $SU(n)$ colors interacting via inverse-square exchange is presented in this article. A class of eigenstates of both the continuum and lattice version of the model Hamiltonians is constructed in terms of the Jastrow-product type wave function. The class of states we construct in this pa

Joel D. Shore, James P. Sethna, Mark Holzer, Veit Elser

Here, we summarize the most important results of our study of logarithmically slow growth of domains following a quench in two models without randomness in their Hamiltonians. This is a slightly updated version of a paper to appear in the Proceedings of the 1st Annual Tohwa University International Symposium, Fukuoka, Japan (American Institute of Physics, 19

C. N. Pope

We review some of the recent developments in the construction of $W$-string theories. These are generalisations of ordinary strings in which the two-dimensional ``worldsheet'' theory, instead of being a gauging of the Virasoro algebra, is a gauging of a higher-spin extension of the Virasoro algebra---a $W$ algebra. Despite the complexity of the (non-linear)

Leonid Dickey

It is well-known that solutions to the string equation are generated by elements of Sato's Grassmannian which are invariant under action of some differential operator. Here it is shown that this operator is nothing else than the infinitesimal operator of the group of additional symmetries of the KdV flow. This is done for KdV hierarchies of arbitrary orders.

Washington Taylor

A new set of realizations of the Virasoro algebra on a bosonic Fock space are found by explicitly computing the Virasoro representations associated with coadjoint orbits of the form (Diff S1) / S1. Some progress is made in understanding the unitary structure of these representations. The characters of these representations are exactly the bosonic partition f

Joel D. Shore, Mark Holzer, James P. Sethna

It is known that in systems which contain randomness explicitly in their Hamiltonians (e.g., due to impurities), the characteristic size L of the ordered domains can grow only logarithmically with time t following a quench below the transition temperature. However, in systems without such imposed randomness, much faster power law growth has generally been pr

Gary W. Gibbons, Malcolm J. Perry

We examine the two-dimensional spacetimes that emerge from string theory. We find all the solutions with no tachyons, and show that the only non-trivial solution is the black hole spacetime. We examine the role of duality in this picture. We then explore the thermodynamics of these solutions which is complicated by the fact that only in two spacetime dimensi

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

Paragrassmann algebras with one and many paragrassmann variables are considered from the algebraic point of view without using the Green ansatz. Operators of differentiation with respect to paragrassmann variables and a covariant para-super-derivative are introduced giving a natural generalization of the Grassmann calculus to a paragrassmann one. Deep relati

U. -J. Wiese, H. -P. Ying

Cluster algorithms are developed for simulating quantum spin systems like the one- and two-dimensional Heisenberg ferro- and anti-ferromagnets. The corresponding two- and three-dimensional classical spin models with four-spin couplings are maped to blockspin models with two-blockspin interactions. Clusters of blockspins are updated collectively. The efficien

U. -J. Wiese, H. -P. Ying

Cluster algorithms are developed for simulating quantum spin systems like the one- and two-dimensional Heisenberg ferro- and anti-ferromagnets. The corresponding two- and three-dimensional classical spin models with four-spin couplings are maped to blockspin models with two-blockspin interactions. Clusters of blockspins are updated collectively. The efficien

Ola Tornkvist

The phase transition of the electroweak vacuum induced by a strong magnetic field is examined, and a connection is made with the Ginzburg-Landau theory of type-II superconductivity. For solutions of the exact nonlinear field equations of the electroweak theory with lattice periodicity in directions perpendicular to the magnetic field, it is proven that, like

H. Dorn, H. -J. Otto

Starting from a covariant and background independent definition of normal ordered vertex operators we give an alternative derivation of the KPZ relation between conformal dimensions and their gravitational dressed partners. With our method we are able to study for arbitrary genus the dependence of N-point functions on all dimensionful parameters. Implication

R. N. Mohapatra, M. K. Parida

We compute the threshold uncertainties due to unknown masses of the Higgs bosons on the predictions for the intermediate and unification scales, $M_I$ and $M_U$ respectively in SO(10) models.We focus on models with separate breaking scales for Parity and $SU(2)_R$ symmetries since they provide a natural realization of the see-saw mechanism for neutrino masse

Paul F. X. Müller

Using stopping time arguments on holomorphic martingales we present a soft way of constructing J. Bourgain's analytic partitions of unity. Applications to Marcinkiewicz interploation in weighted Hardy spaces are discussed.

Dale E. Alspach

About twenty years ago Johnson and Zippin showed that every separable L_1(mu)-predual was isometric to a quotient of C(Delta ), where Delta is the Cantor set. In this note we will show that the natural analogue of the theorem for l_1-preduals does not hold. We will show that there are many l_1-preduals which are not isometric to a quotient of any C(K)-space

Y. Frishman, J. Lukierski, W. J. Zakrzewski

Field-theoretic models for fields taking values in quantum groups are investigated. First we consider $SU_q(2)$ $\sigma$ model ($q$ real) expressed in terms of basic notions of noncommutative differential geometry. We discuss the case in which the $\sigma$ models fields are represented as products of conventional $\sigma$ fields and of the coordinate-indepen

Achi Brandt

The multigrid methodology is reviewed. By integrating numerical processes at all scales of a problem, it seeks to perform various computational tasks at a cost that rises as slowly as possible as a function of $n$, the number of degrees of freedom in the problem. Current and potential benefits for lattice field computations are outlined. They include: $O(n)$

Lawrence Krauss, Martin White

The four observables associated with gravitational lensing of distant quasars by intervening galaxies: image splittings, relative amplifications, time delays, and optical depths, provide separate measures of the strength of the gravitational constant $G$ at cosmological distances. These allow one, in principle, to factor out unknown lensing parameters to dir

David A. Lowe

We consider the S-matrix of c=1 Liouville theory with vanishing cosmological constant. We examine some of the constraints imposed by unitarity. These completely determine (N,2) amplitudes at tree level in terms of the (N,1) amplitudes when the plus tachyon momenta take generic values. A surprising feature of the matrix model results is the lack of particle c

Edward Witten

Topological gravity is equivalent to physical gravity in two dimensions in a way that is still mysterious, though by now it has been proved by Kontsevich. In this paper it is shown that a similar relation between topological and physical Yang-Mills theory holds in two dimensions; in this case, however, the relation can be explained by a direct mapping betwee

B. Eynard, J. Zinn-Justin

In this article we report a preliminary investigation of the large $N$ limit of a generalized one-matrix model which represents an $O(n)$ symmetric model on a random lattice. The model on a regular lattice is known to be critical only for $-2\le n\le 2$. This is the situation we shall discuss also here, using steepest descent. We first determine the critical

Niels Jorgen Nielsen

We prove that if a non-atomic separable Banach lattice in a weak Hilbert space, then it is lattice isomorphic to $L_2(0,1)$.

Jennifer Hodgdon, James P. Sethna

We derive a general crack propagation law for slow brittle cracking, in two and three dimensions, using symmetry, gauge invariance, and gradient expansions. Our derivation provides explicit justification for the ``principle of local symmetry,'' which has been used extensively to describe two dimensional crack growth, but goes beyond that principle to describ

A. Kent

The number of ghost states at each energy level in a non-unitary conformal field theory is encoded in the signature characters of the relevant Virasoro algebra highest weight representations. We give expressions for these signature characters. These results complete Friedan-Qiu-Shenker's analysis of the Virasoro algebra's highest weight representations.

Claudio Coriano', Rajesh R. Parwani, Hidenaga Yamagishi, Ismail Zahed

We argue that the description of meson-nucleon dynamics based on the boson-exchange approach, is compatible with the description of the nucleon as a soliton in the nonrelativistic limit. Our arguments are based on an analysis of the meson-soliton form factor and the exact meson-soliton and soliton-soliton scattering amplitudes in the Sine-Gordon model.

K. Behrndt

I consider a D+1 dimensional nonlinear $\sigma$ model based on a possible interpretation of the Liouville field as a physical time. The Weyl invariance of this theory gives us restrictions for the background fields and the parameters of the theory, e.g.\ for trivial background one obtains the known regions for the dimension of the space-time ($\leq$1 or $\ge

B. ~Gato-Rivera, A. ~M. ~Semikhatov

A direct relation between the conformal formalism for 2d-quantum gravity and the W-constrained KP hierarchy is found, without the need to invoke intermediate matrix model technology. The Kontsevich-Miwa transform of the KP hierarchy is used to establish an identification between W constraints on the KP tau function and decoupling equations corresponding to V

Alexander Kusenko

We present some new mathematical tools which help to derive information about the quark mass matrices directly from experimental data and to elucidate the structure of these mass matrices.

D. Bhowmick, A. K. Ray, S. Raychaudhuri, S. Uma Sankar

We consider an $SU(2)_L \times SU(2)_R \times U(1)_{B-L} \times SU(3)_H^{VL}$ gauge model with natural flavour conservation in the Higgs sector, in which CP-violation occurs due to the horizontal interactions only. We calculate the CP-violating observables $\epsilon$ and $\epsilon'$ of the neutral kaon sector and $d_n$, the electric dipole moment of the neut

A. Kent, G. Watts

The signatures of the inner product matrices on a Lie algebra's highest weight representation are encoded in the representation's signature character. We show that the signature characters of a finite-dimensional Lie algebra's highest weight representations obey simple difference equations that have a unique solution once appropriate boundary conditions are

G. Ferretti, S. G. Rajeev, Z. Yang

We show that baryons of three dimensional Quantum Chromodynamics can be understood as solitons of its effective lagrangian. In the parity preserving phase we study, these baryons are fermions for odd $N_c$ and bosons for even $N_c$, never anyons. We quantize the collective variables of the solitons and there by calculate the flavor quantum numbers, magnetic

G. Ferretti, S. G. Rajeev, Z. Yang

We consider the low energy limit of three dimensional Quantum Chromodynamics with an even number of flavors. We show that Parity is not spontaneously broken, but the global (flavor) symmetry is spontaneously broken. The low energy effective lagrangian is a nonlinear sigma model on the Grassmannian. Some Chern--Simons terms are necessary in the lagrangian to

D. B. Fairlie, J. Govaerts

Finite Euler hierarchies of field theory Lagrangians leading to universal equations of motion for new types of string and membrane theories and for {\it classical} topological field theories are constructed. The analysis uses two main ingredients. On the one hand, there exists a generic finite Euler hierarchy for one field leading to a universal equation whi

K. Kajantie, Leo Karkkainen, K. Rummukainen

We study the coefficients of the expansion $F(R) = 1/3 c_3 R^3 + 1/2 c_2 R^2 + c_1 R$ of the free energy of spherical bubbles at $T=T_c$ in pure glue QCD using lattice Monte Carlo techniques. The coefficient $c_3$ vanishes at $T=T_c$ and our results suggest that the sign and the order of magnitude of $c_1$ is in agreement with the value $c_1=\pm 32\pi T_c^2/

Juan Garcia-Bellido, Mariano Quiros

The cosmology of the string effective action, including one loop string threshold corrections, is analyzed for static compactifications. The stability of the minima of a general supersymmetry breaking potential is studied in the presence of radiation. In particular, it is shown that the radiation bath makes the minima with negative cosmological constant unst

James P. Sethna, Sivan Kartha, Teresa Cast'an, James A. Krumhansl

We've been studying the ``tweed'' precursors above the martensitic transition in shape--memory alloys. These characteristic cross--hatched modulations occur for hundreds of degrees above the first--order shape--changing transition. Our two--dimensional model for this transition, in the limit of infinite elastic anisotropy, can be mapped onto a spin--glass Ha

M Jacob, P V Landshoff

We show in detail how the presence of a heat bath of photons effectively gives charged particles in the final state of a decay process a temperature-dependent mass, and changes the effective strength of the force responsible for the decay. At low temperature, gauge invariance causes both these effects to be largely cancelled by absorption of photons from the

Hiroshi Nohara

We study the topological nature of both isotropic and anisotropic SU(N) Thirring model. It is shown that in the isotropic model there exists the special point where the system lives in the topological phase and that in the anisotropic one which is obtained by introducing two coupling constants and has U(1) symmetry, we present a simple mechanism of the dynam

Omar Foda, Tetsuji Miwa

Let H be the corner-transfer-matrix Hamiltonian for the six-vertex model in the anti-ferroelectric regime. It acts on the infinite tensor product W = V . V . V ....., where is the 2-dimensional irreducible representation of the quantum affine sl(2). We observe that H is the derivation of quantum affine sl(2), and conjecture that the eigenvectors of H form th

Adam F. Falk, Matthias Neubert, Michael Luke

We reformulate the heavy quark effective theory in the presence of a residual mass term, which has been taken to vanish in previous analyses. While such a convention is permitted, the inclusion of a residual mass allows us to resolve a potential ambiguity in the choice of the expansion parameter which defines the effective theory. We show to subleading order

Shahar Ben-Menahem, Adrian Cooper

Alice strings are cosmic strings that turn matter into antimatter. Although they arise naturally in many GUT's, it has long been believed that because of the monopole problem they can have no cosmological effects. We show this conclusion to be false; by using the Langacker-Pi mechanism, monopoles can in fact be annihilated while Alice strings are left intact

Peter Arnold

Broken gauge symmetries are typically restored at high temperature, and the leading-order result for the critical temperature $T_c$ was found many years ago by Weinberg and by Dolan and Jackiw. I find a simple expression for the next-to-leading order correction to $T_c$, which is order $e T_c$ where $e$ is the gauge coupling. The result is a simple consequen

A. Dow, J Steprāns, W. S. Watson

A subset $A$ of a Boolean algebra $B$ is said to be $(n,m)$-reaped if there is a partition of unity $P \subset B$ of size $n$ such that the cardinality of $\{b \in P: b \wedge a \neq \emptyset\}$ is greater than or equal to $m$ for all $a\in A$. The reaping number $r_{n,m}(B)$ of a Boolean algebra $B$ is the minimum cardinality of a set $A \subset B\setminus

Steven B. Giddings, W. M. Nelson

We investigate Hawking radiation from two-dimensional dilatonic black holes using standard quantization techniques. In the background of a collapsing black hole solution the Bogoliubov coefficients can be exactly determined. In the regime after the black hole has settled down to an `equilibrium' state but before the backreaction becomes important these give

D. Daniel, R. Gupta, G. Kilcup, A. Patel

We investigate the use of two types of non-local (``smeared'') sources for quark propagators in quenched lattice QCD at $\beta=6.0$ using Wilson fermions at $\kappa=0.154$ and $0.155$. We present results for the hadron mass spectrum, meson decay constants, quark masses, the chiral condensate and the quark distribution amplitude of the pion. The use of smeare

F. Colomo, A. G. Izergin, V. Korepin

Space and time dependent temepreture correlation fucntions in the Hiesenberg XXO chain are evaluated in the magnetic field. The other name of the model is isotropic xy model in the transverse magnetic field. In the thermodynamic limit correlations in the model are represented as Fredhom determinanat. We expect this to to solve the problem of evaluation of as

M. A. Doncheski, J. L. Hewett

We study the effects of virtual leptoquarks on charged current and neutral current processes at the $ep$ collider HERA. We present the areas of parameter space that can be excluded at HERA by searching for deviations from Standard Model expectations. The best results are obtained by examining the ratio of neutral current to charged current cross sections, $R

Alexander Russakovskii

A method of constructing an entire function with given zeros and estimates of growth is suggested. It gives a possibility to describe zero sets of certain classes of entire functions of one and several variables in terms of growth of volume of these sets in certain polycylinders.

H. Arason, D. J. Castano, E. J. Piard, P. Ramond

Using renormalization group techniques, we examine several interesting relations among masses and mixing angles of quarks and leptons in the Standard Model. We extend the analysis to the minimal supersymmetric extension to determine its effect on these mass relations. Remarkably Supersymmetry allows for these relations to be satisfied at a single grand unifi

F. Delduc, E. Ivanov, E. Sokatchev

We construct a manifestly $N=(4,0)$ world-sheet supersymmetric twistor-like formulation of the $D=6$ Green-Schwarz superstring, using the principle of double (target-space and world-sheet) Grassmann analyticity. The superstring action contains two Lagrange multiplier terms and a Wess-Zumino term. They are written down in the analytic subspace of the world-sh

Apoorva Patel

Sea quark contributions to the scalar density and the axial current matrix elements of the nucleon are studied in lattice qcd with two flavours of dynamical wilson fermions. the results are compared to trends in heavy quark mass expansions, and contrasted with the numbers obtained using dynamical staggered fermions.

James P. Sethna, Ming Huang

We notice some beautiful geometrical defects found in liquid crystals, and explain them by imposing a constraint. We study the way constraints can occur, and introduce the concept of massive fields. We develop the theory of magnetic field expulsion in superconductors as an example. We notice strong analogies with the formation of grain boundaries in crystals

Rahul Basu, Debajyoti Choudhury

A chromoelectric vacuum that confines both gluon and quark degrees of freedom (in the sense that they do not exist as asymptotic states) is constructed. However some degrees of freedom still exist as asymptotic states thereby allowing colour singlets to propagate.

James P. Sethna

We introduce the theoretical framework we use to study the bewildering variety of phases in condensed--matter physics. We emphasize the importance of the breaking of symmetries, and develop the idea of an order parameter through several examples. We discuss elementary excitations and the topological theory of defects.

A. Smailagic, E. Spallucci

We describe the most general treatment of all anomalies both for chiral and massless Dirac fermions, in two-dimensional gravity. It is shown that for this purpose two regularization dependent parameters are present in the effective action. Analogy to the \sc\ model is displayed corresponding to a specific choice of the second parameter, thus showing that the

W. Beirl, E. Gerstenmayer, H. Markum

We investigate the influence of the measure in the path integral for Euclidean quantum gravity in four dimensions within the Regge calculus. The action is bounded without additional terms by fixing the average lattice spacing. We set the length scale by a parameter $\beta$ and consider a scale invariant and a uniform measure. In the low $\beta$ region we obs

Peter Peldan

A generally covariant gauge theory for an arbitrary gauge group with dimension $\geq 3$, that reduces to Ashtekar's canonical formulation of gravity for SO(3,C), is presented. The canonical form of the theory is shown to contain only first class constraints.

Kenichro Aoki, Eric D'Hoker

We generalize the Lax pair and B\"acklund transformations for Toda and N=1 super Toda equations to the case of arbitrary worldsheet background geometry. We use the fact that the Toda equations express constant curvature conditions, which arise naturally from flatness conditions equivalent to the W--gravity equations of motion.

Brian Davies, Omar Foda, Michio Jimbo, Tetsuji Miwa

We diagonalize the anti-ferroelectric XXZ-Hamiltonian directly in the thermodynamic limit, where the model becomes invariant under the action of affine U_q( sl(2) ). Our method is based on the representation theory of quantum affine algebras, the related vertex operators and KZ equation, and thereby bypasses the usual process of starting from a finite lattic

Edward Odell, Thomas Schlumprecht

We prove that Hilbert space is distortable and, in fact, arbitrarily distortable. This means that for all lambda >1 there exists an equivalent norm |.| on l_2 such that for all infinite dimensional subspaces Y of l_2 there exist x,y in Y with ||x||_2 = ||y||_2 =1 yet |x| >lambda |y|. We also prove that if X is any infinite dimensional Banach space with an un

Michael E. Flatte

We present a new method of determining the anisotropy of the gap function in layered high-Tc superconductors. Careful inelastic neutron scattering measurements at low temperature of the phonon dispersion curves in the (100) direction in La_(1.85)Sr_(.15)CuO_4 would determine whether the gap is predominately s-wave or d-wave. We also propose an experiment to

Myron Bander, H. R. Rubinstein

A delicate interplay between the anomalous magnetic moments of the proton and neutron makes, in magnetic fields $B\ge 2\times 10^{14}$ T, the neutron stable and for fields $B\ge 5\times 10^{14}$ T the proton becomes unstable to a decay into a neutron via $\beta$ emission. Limits on the field strengths for which these arguments hold are presented and are rela

Joaquim Gomis, Jordi París

An extension of the Field-Antifield formalism to treat anomalous gauge theories with a closed, irreducible classical gauge algebra is proposed. Introducing extra degrees of freedom, we construct the gauge transformations for these new fields, the Wess-Zumino term and the corresponding measure.

C. S. Aulakh

In theories where spacetime is a direct product of Minkowski space ($M^4$) and a d dimensional compact space ($K^d$), there can exist topological solitons that simultaneously wind around $R^3$ (or $R^2$ or $R^1$) in $M^4$ and the compact dimensions. A paradigmatic non-gravitational example of such ``co-winding" solitons is furnished by Yang-Mills theory defi

D. Espriu, J. Matias

Motivated by some previous work on fermions on random lattices and by suggestions that impurities could trigger parity breaking in 2d crystals, we have analyzed the spectrum of the Dirac equation on a two dimensional square lattice where sites have been removed randomly --- a doped lattice. We have found that the system is well described by a sine-Gordon act

K. M. Bitar, T. A. DeGrand, R. G. Edwards, S. Gottlieb

We present an analysis of hadronic spectroscopy for Wilson valence quarks with dynamical staggered fermions at lattice coupling $6/g^2 = \beta=5.6$ at sea quark mass $am_q=0.01$ and 0.025, and of Wilson valence quarks in quenched approximation at $\beta=5.85$ and 5.95, both on $16^3 \times 32$ lattices. We make comparisons with our previous results with dyna

A. M. Semikhatov

We solve Virasoro constraints on the KP hierarchy in terms of minimal conformal models. The constraints we start with are implemented by the Virasoro generators depending on a background charge $Q$. Then the solutions to the constraints are given by the theory which has the same field content as the David-Distler-Kawai theory: it consists of a minimal matter

Matt Visser

It has recently become fashionable to regard black holes as elementary particles. By taking this suggestion seriously it is possible to cobble together an elementary particle physics based estimate for the decay rate $(\hbox{black hole})_i \to (\hbox{black hole})_f + (\hbox{massless quantum})$. This estimate of the spontaneous emission rate contains two free

J. P. Rodrigues, A. J. van Tonder

A field theoretic formulation of the Marinari-Parisi supersymmetric matrix model is established and shown to be equivalent to a recently proposed supersymmetrization of the bosonic collective string field theory. It also corresponds to a continuum description of super-Calogero models. The perturbation theory of the model is developed and, in this approach, a

A. Klemm, R. Schimmrigk

We investigate a class of (2,2) supersymmetric string vacua which may be represented as Landau--Ginzburg theories with a quasihomogeneous potential which has an isolated singularity at the origin. There are at least three thousand distinct models in this class. All vacua of this type lead to Euler numbers which lie in the range $-960 \leq \chi \leq 960$. The

Hideaki Aoyama, Arihiro Tamura

Path-integral for theories with degenerate vacua is investigated. The origin of the non Borel-summability of the perturbation theory is studied. A new prescription to deal with small coupling is proposed. It leads to a series, which at low orders and small coupling differs from the ordinary perturbative series by nonperturbative amount, but is Borel-summable

Jae-Suk Park

We discuss the algebraic structure of the various BRST symmetries associated with topological Yang-Mills theory as a generalization of the BRS analysis developed for the non-Abelian anomaly in the local Yang-Mills theory. We show that our BRST algebra leads to an extended {\it Russian formula\/} and {\it descent equations}, which contains the descent equatio

Feliks Przytycki, Folkert Tangerman

Consider $d$ disjoint closed subintervals of the unit interval and consider an orientation preserving expanding map which maps each of these subintervals to the whole unit interval. The set of points where all iterates of this expanding map are defined is a Cantor set. Associated to the construction of this Cantor set is the scaling function which records th

Claude Bernard, Maarten Golterman

[This version is a minor revision of a previously submitted preprint. Only references have been changed.] We describe a technique for constructing the effective chiral theory for quenched QCD. The effective theory which results is a lagrangian one, with a graded symmetry group which mixes Goldstone bosons and fermions, and with a definite (though slightly pe

Gerald Dunne, Roman Jackiw

An elementary derivation is given for the ``Peierles substitution'' used in projecting dynamics in a strong magnetic field onto the lowest Landau level. The projection of wavefunctions and the ordering prescription for the projected Hamiltonian is explained.

Gerald Dunne, Roman Jackiw

The two-dimensional self-dual Chern--Simons equations are equivalent to the conditions for static, zero-energy solutions of the $(2+1)$-dimensional gauged nonlinear Schr\"odinger equation with Chern--Simons matter-gauge dynamics. In this paper we classify all finite charge $SU(N)$ solutions by first transforming the self-dual Chern--Simons equations into the

C. G. Torre

Parametrized field theories, which are generally covariant versions of ordinary field theories, are studied from the point of view of the covariant phase space: the space of solutions of the field equations equipped with a canonical (pre)symplectic structure. Motivated by issues arising in general relativity, we focus on: phase space representations of the s

F. Bonechi, E. Celeghini, R. Giachetti, E. Sorace

The 1D Heisenberg spin chain with anisotropy of the XXZ type is analyzed in terms of the symmetry given by the quantum Galilei group Gamma_q(1). We show that the magnon excitations and the s=1/2, n-magnon bound states are determined by the algebra. Thus the Gamma_q(1) symmetry provides a description that naturally induces the Bethe Ansatz. The recurrence rel

Shamit Kachru

We show that there is (p-1)(p'-1) dimensional semi-relative BRST cohomology at each non-positive ghost number in the (p,p') minimal conformal field theory coupled to two dimensional quantum gravity. These closed string states are related to currents and symmetry charges of `exotic' ghost number. We investigate the symmetry structure generated by the most con