November 1992 arXiv papers — page 4

F. Ferrari

The free Maxwell field theory is quantized in the Lorentz gauge on a two dimensional manifold $M$ with conformally flat background metric. It is shown that in this gauge the theory is equivalent, at least at the classical level, to a biharmonic version of the bosonic string theory. This equivalence is exploited in order to construct in details the propagator

D. Boyanovsky, H. J. de Vega

In a scalar field theory, when the tree level potential admits broken symmetry ground states, the quantum corrections to the static effective potential are complex. (The imaginary part is a consequence of an instability towards phase separation and the static effective potential is not a relevant quantity for understanding the dynamics). Instead, we study he

Chang-Pu Sun

In this paper it is shown that a quantum observable algebra, the Heisenberg-Weyl algebra, is just given as the Hopf algebraic dual to the classical observable algebra over classical phase space and the Plank constant is included in this scheme of quantization as a compatible parameter living in the quantum double theory.In this sense,the quantum Yang-Baxter

H. Nishino

We present the {\it canonical} set of superspace constraints for self-dual supergravity, a ``self-dual'' tensor multiplet and a self-dual Yang-Mills multiplet with $~N=1~$ supersymmetry in the space-time with signature $(+,+,-,-)$. For this set of constraints, the consistency of the self-duality conditions on these multiplets with supersymmetry is ma

T. G. Rizzo

Models with explicit R-parity violation can induce new rare radiative decay modes of the $W$ boson into single supersymmetric particles which also violate lepton number. We examine the rate and signature for one such decay, $W\rightarrow \tilde lγ$, and find that such a mode will be very difficult to observe, due its small branching fraction, even if the lep

J. B. Bronzan

We discuss an algorithm for the approximate solution of Schrodinger's equation for lattice gauge theory, using lattice SU(3) as an example. A basis is generated by repeatedly applying an effective Hamiltonian to a ``starting state.'' The resulting basis has a cluster decomposition and long-range correlations. One such basis has about 10^4 states

Mark Bowick, Paul Coddington, Leping Han, Geoffrey Harris

We present the results of a set of Monte Carlo simulations of Dynamically Triangulated Random Surfaces embedded in three dimensions with an extrinsic curvature dependent action. We analyze several observables in the crossover regime and discuss whether or not our observations are indicative of the presence of a phase transition.

W. Beirl, E. Gerstenmayer, H. Markum

Euclidean quantum-gravity path-integrals are investigated within Regge calculus by computer simulations. The domain of integration is restricted by introducing a lower limit for the fatness of each simplex. We use the standard hypercubic triangulation of the 4-torus and irregularly triangulated lattices obtained by inserting a small number of vertices using

C J Griffin, T D Kieu

Comparing random lattice, naive and Wilson fermions in two dimensional abelian background gauge field, we show that the doublers suppressed in the free field case are revived for random lattices in the continuum limit unless gauge interactions are implemented in a non--invariant way.

N. Mohammedi

We describe the geomety of a set of scalar fields coupled to gravity. We consider the formalism of a differential Z_2-graded algebra of $2\times 2$ matrices whose elements are differential forms on space-time. The connection and the vierbeins are extended to incorporate additional scalar and vector fields. The resulting action describes two universes coupled

Peter Peldan

A gauge and diffeomorphism invariant theory in (2+1)-dimensions is presented in both first and second order Lagrangian form as well as in a Hamiltonian form. For gauge group $SO(1,2)$, the theory is shown to describe ordinary Einstein gravity with a cosmological constant. With gauge group $G^{tot}=SO(1,2)\otimes G^{YM}$, it is shown that the equations of mot

N. I. Karchev, T. S. Hristov

A graded H.P,realization of the SU(2|1) algebra is proposed.A spin-wave theory with a condition that the sublattice magnetization is zero is discussed.The long-range spiral phase is investigated.The spin-spin correlator is calculated.

Katherine Freese, Janna J Levin

A cosmology with a dynamical Planck mass $m_{pl}$ is shown to solve the horizon and monopole problems (and possibly flatness) if there is an early MAD (modified aging) era where the universe becomes older than in the standard model as a result of a large $m_{pl}$: the causality condition is $m_{pl}(T_c)/ m_{pl}(T_o) \gta T_c/T_o$ ($T_c$ is some high temperat

M. Bershadsky, W. Lerche, D. Nemeschansky, N. P. Warner

We show that almost all string theories, including the bosonic string, the superstring and $W$-string theories, possess a twisted N=2 superconformal symmetry. This enables us to establish a connection between topological gravity and the field theoretical description of matter coupled to gravity. We also show how the \brs operators of the $W_n$-string can be

Daniel Huybrechts, Manfred Lehn

We describe stability conditions for pairs consisting of a coherent sheaf and a homomorphism to a fixed coherent sheaf on a projective variety. The corresponding moduli spaces are constructed for pairs on curves and surfaces. We consider two examples. The fixed sheaf is the structure sheaf or is a vector bundle on a divisor, i.e. Higgs pairs or framed bundle

S. N. Solodukhin

We construct the theory of non-abelian gauge antisymmetric tensor fields, which generalize the standard Yang-MIlls fields and abelian gauge p-forms. The corresponding gauge group acts on the space of inhomogeneous differential forms and it is shown to be a supergroup. The wide class of generalized Chern-Simons actions is constructed.

S. Pratik Khastgir, Jnanadeva Maharana

The dimensional reduction technique is adopted to derive string effective action. Wormhole solutions corresponding to space-time geometries $R^1\times S^1\times S^2$ and $R^1\times S^3$ are presented. The duality and SL(2,R) symmetries are implemented to generate new wormhole solutions.

R. Ch. Rashkov

Integrable hierarchy based on the constrained Osp(2$\mid%2) connection is considered. The connection with 2D supergravity and some analogies with the W$_3^{(2)}$ case are given. It is shown that super Virasoro transformations are symmetries of tha hierarchy.

F. David, B. Duplantier, E. Guitter

We consider a continuous model of D-dimensional elastic (polymerized) manifold fluctuating in d-dimensional Euclidean space, interacting with a single impurity via an attractive or repulsive delta-potential (but without self-avoidance interactions). Except for D=1 (the polymer case), this model cannot be mapped onto a local field theory. We show that the use

Q-Han Park

A master equation ( $n$ dimensional non--Abelian current conservation law with mutually commuting current components ) is introduced for multi-dimensional non-linear field theories. It is shown that the master equation provides a systematic way to understand 2-d integrable non-linear equations as well as 4-d self-dual equations and, more importantly, their g

Lawrence Connors, Ashley J. Deans, John S. Hagelin

We show that supersymmetry automatically leads to density fluctuations $ΔT/T\sim6\times10^{-6}$ in agreement with the recent COBE measurement.

V. Barger, N. G. Deshpande, J. L. Hewett, T. G. Rizzo

We investigate the possibility of a multi-Higgs doublet model where the lightest neutral Higgs boson ($h^0$) decouples from the fermion sector. We are partially motivated by the four $\ell^+\ell^-γγ$ events with $M_{γγ}\simeq60$\,GeV recently observed by the L3 collaboration, which could be a signal for $Z\to (Z^*\to \ell^+\ell^-)+(h^0\to γγ)$. Collider sign

Damien Pierce

We investigate the discrepancy that exists at low-$x_T=2p_T/\sqrt{s}$ between the next--to--leading order QCD calculations of prompt photon production and the measured cross section. The central values of the measured cross section are of order 100\% larger than QCD predictions in this region. It has been suggested that the bremsstrahlung contribution may ac

N. G. Deshpande, E. Keith, Palash B. Pal

We consider the breaking of the grand unification group $SO(10)$ to the standard model gauge group through several chains containing two intermediate stages. Using the values of the gauge coupling constants at scale $M_Z$ derived from recent LEP data, we determine the range of their intermediate and unification scales. In particular, we identify those chains

A. D. Dolgov, K. Kainulainen

We derive an equation for the evolution of the number density of a massive particle species in the early Universe, which correctly accounts for the Fermi-Dirac (FD) statistics. The FD-corrections are sizable and potentially important if the decoupling from the thermal equilibrium takes place at temperatures of the order of, or less than the mass of the parti

D. Comelli

The neutral Higgs sector of the Minimal non Minimal Supersymmetric Standard Model is considered. By effective potential and R.G.E. supported method; an upper bound of the lightest Higgs is analysed. From the request of perturbativity of the coupling in the superpotential, adding the leading stop top contributions, the absolute bound of $\sim 130$ GeV for $90

B. Moussallam

The so called Casimir energy embodies the O($(N_c)^0$) contribution to the skyrmion mass according to the semi-classical expansion theory of solitons. We claim that this contribution can be accurately estimated despite the fact that some of the counterterms, provided in principle by chiral perturbation theory, are not known in practice. Using $ζ$ function te

Geoffrey T. Bodwin, Eve V. Kovacs

We discuss the use of renormalization counterterms to restore the chiral gauge symmetry in a lattice theory of Wilson fermions. We show that a large class of counterterms can be implemented automatically by making a simple modification to the fermion determinant.

C. Bernard, C. Parrinello, A. Soni

We give preliminary numerical results for the gluon propagator evaluated both in coordinate and momentum space on a 16^3X40 quenched lattice at beta=6.0. Our findings are compared with earlier results in the literature at zero momentum. In addition, by considering nonzero momenta we attempt to extract the form of the propagator and compare it to continuum pr

M. -C. Chu, J. M. Grandy, S. Huang, J. W. Negele

Point-to-point correlation functions of hadron currents in the QCD vacuum are calculated on a lattice and analyzed using dispersion relations, providing physical information down to small spatial separations. Qualitative agreement with phenomenological results is obtained in channels for which experimental data are available, and these correlation functions

Daniel Cangemi, Martin Leblanc, Robert B. Mann

We compute the group element of SO(2,2) associated with the spinning black hole found by Bañados, Teitelboim and Zanelli in (2+1)-dimensional anti-de Sitter space-time. We show that their metric is built with SO(2,2) gauge invariant quantities and satisfies Einstein's equations with negative cosmological constant everywhere except at $r=0$. Moreover, alt

Thomas A. Roman

It has been speculated that Lorentzian wormholes of the Morris- Thorne type might be allowed by the laws of physics at submicroscopic, e.g. Planck, scales and that a sufficiently advanced civilization might be able to enlarge them to classical size. The purpose of this paper is to explore the possibility that inflation might provide a natural mechanism for t

Shane J. Hughes, Des J. Mc Manus, Michel A. Vandyck

A weak-field solution of Einstein's equations is constructed. It is generated by a circular cosmic string externally supported against collapse. The solution exhibits a conical singularity, and the corresponding deficit angle is the same as for a straight string of the same linear energy density. This confirms the deficit-angle assumption made in the Fro

Masakatsu Kenmoku, Yuko Okamoto, Kazuyasu Shigemoto

We study a generalized Einstein theory with the following two criteria:{\it i}) on the solar scale, it must be consistent with the classical tests of general relativity, {\it ii}) on the galactic scale, the gravitational potential is a sum of Newtonian and Yukawa potentials so that it may explain the flat rotation curves of spiral galaxies. Under these crite

Massimo Capaccioli, Nicola Caon, Mauro D'Onofrio

Two families of hot stellar systems, named {\it `ordinary'\/} and {\it 'bright'\/}, are identified in the ($\log R_e, μ_e$) plane built with a luminosity--limited sample of ellipticals and bulges of S0s and spirals of the Virgo and Fornax clusters. This finding, based on {\it ad hoc\/} new observations, is confirmed by a much larger set of litera

J. M. Figueroa-O'Farrill, E. Ramos

Radul has recently introduced a map from the Lie algebra of differential operators on the circle to $W_n$. In this note we extend this map to $W_{KP}^{(q)}$, a recently introduced one-parameter deformation of $W_{KP}$---the second hamiltonian structure of the KP hierarchy. We use this to give a short proof that $W_\infty$ is the symmetry algebra of additiona

J. Lopez, D. Nanopoulos, H. Pois, A. Zichichi

A series of predictions are worked out in order to put the minimal $SU(5)$ supergravity model under experimental test. Using the two-loop gauge coupling renormalization group equations, with the inclusion of supersymmetric threshold corrections, we calculate a new value for the proton decay rate in this model and find that SuperKamiokande and Gran Sasso shou

A. Y. Shiekh

Besides having some very interesting perturbatively unstable orbits, it seems that for a Schwarzschild black hole, below $r=3M$, the force always increases inward with increasing angular momentum. Here this previously known result is derived with greater simplicity, and a similar analysis is performed for black holes with angular momentum and charge.

Stefano Forte

We show that the Bjorken sum rule for the first moment of the polarized nucleon structure function $g_1$ is not necessarily satisfied in QCD if the axial anomaly is taken into account. We argue that nonperturbative QCD effects should lead to a violation of the sum rule of the order of the percentage isospin violation in current quark masses.

Arjan Hulsebos

Write-up for Lattice'92, held in Amsterdam. preprint LTH 291. Comes with 6 PostScript figures and 1 sty-file. We study the nature of gauge fixing ambiguities in two dimensional gauge theories. We find that these ambiguities can be related to the asociated spin model. They can be eliminated by means of a (multigrid) annealing algorithm.

Arthur Kosowsky, Michael S. Turner

We introduce an approximation to calculate the gravitational radiation produced by the collision of true-vacuum bubbles that is simple enough to allow the simulation of a phase transition by the collision of hundreds of bubbles. This ``envelope approximation'' neglects the complicated ``overlap'' regions of colliding bubbles and follows only

Federico Ferrini, Bianca Maria Poggianti

We present a multiphase model for the evolution of elliptical galaxies. Diffuse gas, molecular clouds, stars and remnants are taken into account. Cloud--cloud collisions and stimulated processes are the main causes of star formation. The occurrence of winds driven by Supernovae is considered, and the evolution of the system is computed also after the first w

B. Holdom, M. Sutherland

A simple relativistic model of heavy-quark-light-quark mesons is proposed. In an expansion in inverse powers of the heavy quark mass we find that all zeroth and first order heavy quark symmetry relations are satisfied. The main results are: - the difference between the meson mass and the heavy quark mass plays a significant role even at zeroth order; - the s

W. Nahm, A. Recknagel, M. Terhoeven

Dilogarithm identities for the central charges and conformal dimensions exist for at least large classes of rational conformally invariant quantum field theories in two dimensions. In many cases, proofs are not yet known but the numerical and structural evidence is convincing. In particular, close relations exist to fusion rules and partition identities. We

Thomas Appelquist, John Terning

We consider the relation between the breakdown scale of chiral perturbation theory, $Λ_χ$, for large values of $N$ (flavor), and the scale associated with ``new" physical thresholds. This question is addressed using both the linear $σ$ model and an asymptotically-free gauge theory to describe the high energy dynamics. It is suggested that the massive phy

Marcelo Gleiser, Rudnei O. Ramos

We examine the validity of the 1-loop approximation to the effective potential at finite temperatures and present a simple test for its reliability. As an application we study the standard electroweak potential, showing that for a Higgs mass above 70 GeV, and afirly independent of the top mass (with $m_{t} > 90 GeV$, the 1-loop approximation is no longer val

G. C. Marques, Rudnei O. Ramos

In this paper we show how to compute in a consistent way nucleation rates in field theory at finite temperatures, with metastable vacuum. Using the semiclassical approach in field theory at finite temperature we show that the prefactor term can be calculated explicitly (in the thin-wall approximation) and that the same provides exponential finite temperature

HoSeong La

Classical vortex solutions in $(1+2)$-dimensional multi-Higgs systems are studied. In particular the existence of such a solution requires equal characteristic lengths and a specific relation between the ratio of the two Higgs vacuum expectation values and the couplings in the Higgs potential, if $λ_3\neq 0$.

Yoonbai Kim, Kimyeong Lee

We consider vortex dynamics in self-dual Chern-Simons Higgs systems. We show that the naive Aharanov-Bohm phase is the inverse of the statistical phase expected from the vortex spin, and that the self-dual configurations of vortices are degenerate in energy but not in angular momentum. We also use the path integral formalism to derive the dual formulation of

Silvia Penati, Daniela Zanon

: We consider two--dimensional supersymmetric Toda theories based on the Lie superalgebras $A(n,n)$, $D(n+1,n)$ and $B(n,n)$ which admit a fermionic set of simple roots and a fermionic untwisted affine extension. In particular, we concentrate on two simple examples, the $B(1,1)$ and $A(1,1)$ theories. Both in the conformal and massive case we address the iss

Toshiki Isse

Dynamics of quantized free fields ( of spin 0 and 1/2 ) contained in a subspace $V_*$ of an N+4 dimensional flat space $V$ is studied. The space $V_*$ is considered as a neighborhood of a four dimensional submanifold $M$ arbitrarily embedded into $V$. We show that Einstein SO(N)-Yang-Mills Higgs theory is induced as a low energy effective theory of the syste

J. -L. Basdevant, E. L. Berger, D. Dicus, C. Kao

In the standard Higgs model of electroweak symmetry breaking, the Higgs boson is associated with both vector-boson and fermion mass generation. In contrast, we discuss a two-Higgs-doublet model in which these masses are associated with two different scalar bosons. We show that the Higgs boson associated with vector-boson mass generation produces a {\it dip\/

N. G. Deshpande, E. Keith, Palash B. Pal

We give a detailed renormalization group analysis for the SU(16) grandunified group with general breaking chains in which quarks and leptons transform separately at intermediate energies. Our analysis includes the effects of Higgs bosons. We show that the grandunification scale could be as low as $\sim 10^{8.5}$ GeV and give examples where new physics could

Adam F. Falk, Michael Luke, Mark B. Wise

We reconsider the recent derivation by de Rafael and Taron of bounds on the slope of the Isgur-Wise function. We argue that one must be careful to include cuts starting below the heavy meson pair production threshold, arising from heavy quark-antiquark bound states, and that if such cuts are properly accounted for then no constraints may be derived.

Mauro Anselmino, Stefano Forte

We show that a large anomalous contribution due to nonperturbative instanton-like gluonic field configurations to the axial charge of the proton implies high-energy spin effects in $p-p$ elastic scattering. This is the same mechanism which is responsible for anomalous baryon number violation at high energy in the standard model. We compute the proton polariz

Rudnei O. Ramos

We apply the $δ$-expansion perturbation scheme to the $λϕ_{4}$ self-interacting scalar field theory in 3+1 D at finite temperature. In the $δ$-expansion the interaction term is written as $λ(ϕ^{2})^{1 + δ}$ and $δ$ is considered as the perturbation parameter. We compute, in this perturbation approach, the renormalized mass at finite temperature from which we

Maria Smizanska, Julius Hrivnac

A possibility to measure CP-violation in B0-decays by ATLAS experiment was investigated. With one year of running at luminosity 10^33 cm-2s-1 with a muon pt-trigger threshold of 20GeV and rapidity coverage eta<2.5 of the tracking detector the rate of 1490 events B0->J/psi->mumupipi can be reached.

Benjamin Grinstein, Paul F. Mende

We examine the recent work of de Rafael and Taron where model-independent bounds on the Isgur-Wise function are presented. We first argue that the bounds cannot hold in as much generality as implied. We show that the effects of resonances omitted in their discussion (such as heavy-heavy ``onium&#39;&#39; states below threshold) modify the bound. The resultin

Claude Bernard, Maarten Golterman

We present results for physical quantities computed in quenched chiral perturbation theory and compare them with the corresponding unquenched expressions. We also point out an apparent theoretical problem of the quenched approximation. latex, file espcrc2.sty needed (appended at the end: search for espcrc2.sty).

S. Deser

We analyze the degree of equivalence between abelian topologically massive, gauge-invariant, vector or tensor parity doublets and their explicitly massive, non-gauge, counterparts. We establish equivalence of field equations by exploiting a generalized Stueckelberg invariance of the gauge systems. Although the respective excitation spectra and induced source

T. Banks, M. O&#39;Loughlin, A. Strominger

Magnetically charged dilatonic black holes have a perturbatively infinite ground state degeneracy associated with an infinite volume throat region of the geometry. A simple argument based on causality is given that these states do not have a description as ordinary massive particles in a low-energy effective field theory. Pair production of magnetic black ho

M. Chaichian, J. F. Gomes, P. Kulish

We present an operator formulation of the q-deformed dual string model amplitude using an infinite set of q-harmonic oscillators. The formalism attains the crossing symmetry and factorization and allows to express the general n-point function as a factorized product of vertices and propagators.

David Hochberg, Thomas Kephart, James W. York

Quantum stress-energy tensors of fields renormalized on a Schwarzschild background violate the classical energy conditions near the black hole. Nevertheless, the associated equilibrium thermodynamical entropy $\Delta S$ by which such fields augment the usual black hole entropy is found to be positive. More precisely, the derivative of $\Delta S$ with respect

J. Kowalski-Glikman

As compared to the previous version, the example of Gupta-Bleuler quantization of massive electrodynamics was added, and the derivation of path integral for anomalous theories is further elaborated. This is the final version to be published in Annals of Physics.

G. Rosensteel

The Kelvin circulation is the kinematical Hermitian observable that measures the true character of nuclear rotation. For the anisotropic oscillator, mean field solutions with fixed angular momentum and Kelvin circulation are derived in analytic form. The cranking Lagrange multipliers corresponding to the two constraints are the angular and vortex velocities.

S. J. Pollock, E. N. Fortson, L. Wilets

There have been suggestions to measure atomic parity nonconservation (PNC) along an isotopic chain, by taking ratios of observables in order to cancel complicated atomic structure effects. Precise atomic PNC measurements could make a significant contribution to tests of the Standard Model at the level of one loop radiative corrections. However, the results a

Alexander Koldobsky

For $n\geq 2, p<2$ and $q>2,$ does there exist an $n$-dimensional Banach space different from Hilbert spaces which is isometric to subspaces of both $L_{p}$ and $L_{q}$? Generalizing the construction from the paper &#34;Zonoids whose polars are zonoids&#34; by R.Schneider we give examples of such spaces. Moreover, for any compact subset $Q$ of $(0,\infty)\se

Nigel J. Kalton, Beata Randrianantoanina

We prove that if $X$ is a real rearrangement-invariant function space on $[0,1]$, which is not isometrically isomorphic to $L_2,$ then every surjective isometry $T:X\to X$ is of the form $Tf(s)=a(s)f(σ(s))$ for a Borel function $a$ and an invertible Borel map $σ:[0,1] \to [0,1].$ If $X$ is not equal to $L_p$, up to renorming, for some $1\le p\le \infty$ then

Leonardo Castellani

We find the R matrix for the inhomogeneous quantum groups whose homogeneous part is $GL_q(n)$, or its restrictions to $SL_q(n)$,$U_q(n)$ and $SU_q(n)$. The quantum Yang-Baxter equation for R holds because of the Hecke relation for the braiding matrix of the homogeneous subgroup. A bicovariant differential calculus on $IGL_q(n)$ is constructed, and its applic

J. Pantaleone, A. Halprin, C. N. Leung

Massless neutrinos will mix if their couplings to gravity are flavor dependent, i.e., violate the principle of equivalence. Because the gravitational interaction grows with neutrino energy, the solar neutrino problem and the recent atmospheric neutrino data may be simultaneously explained by violations at the level of 1E-14 to 1E-17 or smaller. This possibil

A. Abada, D. Kalafatis, B. Moussallam

Isospin one vector mesons (in particular the $ρ$) are usually described as massive Yang-Mills particles in the chiral Lagrangian. We investigate some aspects of an alternative approach in the soliton sector. It is found that the soliton is stable in very much the same way as with the $ω$-meson and that spontaneous parity violating classical solutions do not

K. Funakubo, S. Otsuki, K. Takenaga, F. Toyoda

\noindent A formalism based on path-integral expression of time-evolution operator during tunneling at a finite energy proposed by the authors is applied to $SU(2)$ gauge-Higgs system to produce Higgs particles with $ΔB=1$. Instead of starting from instanton tunneling at the zero energy, a classical bounce solution giving sphaleron (instanton) action at high

Anna Hasenfratz

We investigate the gauge interaction induced by heavy fermions using both dimensional and lattice regularization. We study the condition under which heavy fermions induce a continuum gauge theory.

B. Alles, M. Campostrini, A. Feo, H. Panagopoulos

We present some new three-loop results in lattice gauge theories, for the Free Energy and for the Topological Susceptibility. These results are an outcome of a scheme which we are developing (using a symbolic manipulation language), for the analytic computation of renormalization functions on the lattice.

A. Billoire, T. Neuhaus, B. Berg

We present the results of a multicanonical simulation of the q=20 2-d Potts model in the transition region. This is a very strong first order phase transition. We observe, for the first time, the asymptotic finite size scaling behavior predicted by Borgs and Kotecký close to a first order phase transition point.

S. Caracciolo, G. Parisi, A. Pelissetto

We introduce a model of self-repelling random walks where the short-range interaction between two elements of the chain decreases as a power of the difference in proper time. Analytic results on the exponent $ν$ are obtained. They are in good agreement with Monte Carlo simulations in two dimensions. A numerical study of the scaling functions and of the effic

M. -C. Chu, J. M. Grandy, S. Huang, J. W. Negele

Results from the first lattice QCD analysis of vacuum correlators of local hadronic currents using dispersion relations are presented. We have explored the vector, pseudoscalar, axial, and scalar meson channels, and the proton-like and delta-like baryon channels. The lattice results are shown to agree qualitatively with experimental results in channels where

David Hochberg, Thomas W. Kephart

The order $\hbar$ fluctuations of gauge fields in the vicinity of a blackhole can create a repulsive antigravity region extending out beyond the renormalized Schwarzschild horizon. If the strength of this repulsive force increases as higher orders in the back-reaction are included, the formation of a wormhole-like object could occur.

Jonathan Halliwell, Miguel Ortiz

The scope of the paper has been broadened to include a more complete discussion of the following topics: The derivation of composition laws in quantum cosmology. The connection between the existence of a composition law in the sum over histories approach to relativistic quantum mechanics and quantum cosmology, and the existence of a canonical formulation.

Kay-Thomas Pirk

Reversing a slight detrimental effect of the mailer related to TeXability

G. Amelino-Camelia, S. -Y. Pi

We present a self-consistent calculation of the finite temperature effective potential for $λϕ^4$ theory, using the composite operator effective potential in which an infinite series of the leading diagrams is summed up. Our calculation establishes the proper form of the leading correction to the perturbative one-loop effective potential.

Gerald B. Cleaver

Using the factorization approach of Gepner and Qiu, I systematically rederive the closed fractional superstring partition functions for K= 4, 8, and 16. For these theories the relationship between the massless graviton and gravi- tino sector and the purely massive sectors is explored. Properties of the massive sectors are investigated. A twist current in the

Robert C. Myers, Vipul Periwal

Using recent advances in the understanding of non-critical strings, we construct a unique, conformally invariant continuation to off-shell momenta of Polyakov amplitudes in critical string theory. Three-point amplitudes are explicitly calculated. These off-shell amplitudes possess some unusual, apparently stringy, characteristics, which are unlikely to be re

P. C. Tiemeijer, J. A. Tjon

A method is described for solving relativistic quasi-potential equations in configuration space. The Blankenbecler-Sugar-Logunov-Tavkhelidze and an equal-time equation, both relativistic covariant two-body equations containing the full Dirac structure of positive and negative energy states, are studied in detail. These equations are solved for a system of tw

S. Stieberger

We derive the four point correlation function involving four twist fields for arbitrary even dimensional Z_N x Z_M orbifold compactifications. Using techniques from the conformal field theory the three point correlation functions with twist fields are determined. Both the choice of the modular background (compatible with the twists) and of the (higher) twist

Holger Ewen, Oleg Ogievetsky

We construct for all $N$ a solution of the Frenkel--Moore $N$--simplex equation which generalizes the $R$--matrix for the Jordanian quantum group.

Nathan Berkovits

In a recent paper, the BRST formalism for the gauge-fixed N=2 twistor-string was used to calculate Green-Schwarz supersring scattering amplitudes with an arbitrary number of loops and external massless states. Although the gauge-fixing procedure preserved the worldsheet N=2 superconformal invariance of the twistor-string, it broke the target-space SO(9,1) su

J. Grundberg, U. Lindstrom, H. Nordstrom

Requiring that the path integral has the global symmetries of the classical action and obeys the natural composition property of path integrals, and also that the discretized action has the correct naive continuum limit, we find a viable discretization of the (D=3,N=2) superparticle action.

Achim Kempf

In quantum field theory the creation and annihilation operators that are located at the points in 3-momentum space have commutation relations that are conserved under the action of a $U({\infty})$ group. Here it is shown how to define an appropriate $U_q({\infty})$ which then leads to deformed commutation relations. A formalism that was previously defined fo

Achim Kempf

Usually in quantum mechanics the Heisenberg algebra is generated by operators of position and momentum. The algebra is then represented on an Hilbert space of square integrable functions. Alternatively one generates the Heisenberg algebra by the raising and lowering operators. It is then natural to represent it on the Bargmann Fock space of holomorphic funct

M. Gasperini, G. Veneziano

The duality-type symmetries of string cosmology naturally lead to a pre-big-bang phase of accelerated evolution as dual counterpart of the decelerated expansion of standard cosmology. We discuss several properties of this scenario, including the possibility that tracks of the pre-big-bang may be found either in the spectrum of relic gravitons or in the disto

J. Gamboa, C. Ramirez

We study $2D$ supergravity in a covariant and gauge independent way. The theory is obtained from $2D$ bosonic gravity following the square root method and the diffeomorphism superalgebra is explicitly computed. We argue that our approach could be a procedure for introducing nontrivial physics in quantum $2D$ (super)gravity.

K. Ito, J. O. Madsen, J. L. Petersen

We consider the extended superconformal algebras of the Knizhnik-Bershadsky type with $W$-algebra like composite operators occurring in the commutation relations, but with generators of conformal dimension 1,$\frac{3}{2}$ and 2, only. These have recently been neatly classified by several groups, and we emphasize the classification based on hamiltonian reduct

L. Benoit, Y. Saint-Aubin

Bauer, Di Francesco, Itzykson and Zuber proposed recently an algorithm to construct all singular vectors of the Virasoro algebra. It is based on the decoupling of (already known) singular fields in the fusion process. We show how to extend their algorithm to the Neveu-Schwarz superalgebra.

Renata Kallosh, Tomas Ortin, Amanda Peet

We present a detailed calculation of the entropy and action of $U(1)~2$ dilaton black holes, and show that both quantities coincide with one quarter of the area of the event horizon. Our methods of calculation make it possible to find an explanation of the rule $S = A/4$ for all static, spherically symmetric black holes studied so far. We show that the only

John S. Hagelin, S. Kelley

We review the theoretical and experimental status of minimal grand unified theories (GUTS), contrasting the failure of minimal non-supersymmetric $SU(5)$ with the success of the minimal supersymmetric $SU(5)$ and minimal supersymmetric Flipped $SU(5)\times U(1)$ models. We show that a reasonable value for the universal soft supersymmetry-breaking gaugino mas

Donald S. Shaw, Ray R. Volkas

Despite its great success in explaining the basic interactions of nature, the standard model suffers from an inability to explain the observed masses of the fundamental particles and the weak mixing angles between them. We shall survey a set of possible extensions to the standard model, employing an SU(2) ``horizontal&#39;&#39; gauge symmetry between the par

Walter Wilcox

The results of a lattice simulation of time-separated charge overlap for the charged pion are discussed. The expected result $\sim {\rm exp}[-(E_q - m_π)t\,]$ for large charge density overlap time separations, $t$, is clearly visible in the Fourier transform, indicating that the elastic limit can be achieved at low to medium momentum values on present-sized

Martin Hasenbusch, Klaus Pinn

We compute properties of the interface of the 3-dimensional Ising model for a wide range of temperatures and for interface extensions up to 64 by 64. The interface tension sigma is obtained by integrating the surface energy density over the inverse temperature beta. The surface stiffness coefficient kappa is determined. We also study universal quantities lik

B. Grossmann, M. L. Laursen, T. Trappenberg, U. -J. Wiese

The reduced tension $\sigma_{cd}$ of the interface between the confined and the deconfined phase of $SU(3)$ pure gauge theory is determined from numerical simulations of the first transfer matrix eigenvalues. At $T_c = 1/L_t$ we find $\sigma_{cd} = 0.139(4) T_c^2$ for $L_t = 2$. The interfaces show universal behavior because the deconfined-deconfined interfa