arXiv papers from January 1993

D. Depireux, P. Mathieu

We display a new integrable perturbation for both N=1 and N=2 superconformal minimal models. These perturbations break supersymmetry explicitly. Their existence was expected on the basis of the classification of integrable perturbations of conformal field theories in terms of distinct classical KdV type hierarchies sharing a common second Hamiltonian structu

H. S. Sharatchandra

The mechanism underlying any bosonisation or fermionisation is exposed.It is shown that any local theory of fermions on a lattice in any spatial dimension greater than one is equivalent to a local theory of Ising spins coupled to a $Z_{2}$ gauge field.There is a close relation to the description of anyons using a Chern-Simons term.

B. A. Campbell, N. Kaloper, R. Madden, K. A. Olive

We consider the physical properties of four dimensional black hole solutions to the effective action describing the low energy dynamics of the gravitational sector of heterotic superstring theory. We compare the properties of the external field strengths in the perturbative solution to the full $O(\alpha')$ string effective action equations, to those of exac

K. G. Selivanov

We apply the coadjoint orbit technique to the group of area preserving diffeomorphisms (APD) of a 2D manifold, particularly to the APD of the semi-infinite cylinder which is identified with $w_{\infty}$. The geometrical action obtained is relevant to both $w$ gravity and 2D turbulence. For the latter we describe the hamiltonian, which appears to be given by

Michael Booth

I show that the electric dipole moment of the W-boson vanishes to two loop order in the Standard KM model. As a consequence, the electric dipole moment of the electron vanishes to three loop order. Including QCD corrections may give a non-vanishing result; I estimate d_W \approx 8 10^-31 ecm which induces an electron EDM \approx 8 10^-41 ecm, considerably sm

Zhi-Jie Chen

For a complex surface of general type with a relatively minimal genus 2 fibration, the bounds of the orders of the automorphism group of the fibration, of its abelian subgroups and of its cyclic subgroups are determined as linear functions of $c^2_1$. Most of them are the best.

C. A. Barnes, S. E. Koonin, K. Langanke

We demonstrate that the cross sections derived from the "shadow model" for reactions between light nuclei disagree with low-energy laboratory data and exhibit unphysical behavior at energies below those for which data exist. As a consequence, the large thermonuclear reaction rates obtained by Scalia and Figuera [Phys. Rev. C46, 2610 (1992)] are wrong.

Philippe Ruelle

We classify the automorphisms of the (chiral) level-k affine SU(3) fusion rules, for any value of k, by looking for all permutations that commute with the modular matrices S and T. This can be done by using the arithmetic of the cyclotomic extensions where the problem is naturally posed. When k is divisible by 3, the automorphism group (Z_2) is generated by

E. W. Mielke, J. D. McCrea, Y. Ne'eman, F. W. Hehl

In quantum models of gravity, it is surmized that configurations with degenerate coframes could occur during topology change of the underlying spacetime structure. However, the coframe is not the true Yang--Mills type gauge field of the translations, since it lacks the inhomogeneous gradient term in the gauge transformations. By explicitly restoring this ``h

O. F. Dayi

BFV--BRST charge for q-deformed algebras is not unique. Different constructions of it in the classical as well as in the quantum phase space for the $q$-deformed algebra sl_q(2) are discussed. Moreover, deformation of the phase space without deforming the generators of sl(2) is considered. $\hbar$-q-deformation of the phase space is shown to yield the Witten

T. R. Govindarajan, R. Shankar, N. Shaji, M. Sivakumar

Following our earlier work we argue in detail for the equivalence of the nonlinear $\sigma$ model with Hopf term at~$\theta=\pi/2s$ ~and an interacting spin-s theory. We give an ansatz for spin-s operators in the $\sigma$ model and show the equivalence of the correlation functions.We also show the relation between topological and Noether currents. We obtain

Biman Nath, David Eichler

The possibility of detecting proto-galaxies in the UV band is pointed out, assuming that galaxy formation occured at z $\sim 5-6$. It is shown that the diffuse gas in collapsing galaxy sized objects with temperatures $\sim 10^{6\pm0.5}$ K, and with a modest amount of metallicity, should copiously produce emission lines from highly ionized Iron atoms. The exp

J. A. Gracey

By considering corrections to the asymptotic scaling functions of the photon and electron in quantum electrodynamics with $\Nf$ flavours, we solve the skeleton Dyson equations at $O(1/\Nf)$ in the large $\Nf$ expansion at the $d$-dimensional critical point of the theory and deduce the critical exponent $\beta^\prime(g_c)$, in arbitrary dimensions, and subseq

N. Bilić, J. Cleymans, E. Suhonen, D. W. von Oertzen

We propose a mechanism which naturally contains the relation $\mu_{B} = 3\mu_{S}$ of the hadronic gas produced in heavy-ion collisions at CERN. Our starting assumption is the existence of a sharp front separating the quark-gluon plasma phase from the hadronic phase. Energy-momentum conservation across the front leads to the following consequences for an adia

F. De Jonghe, R. Siebelink, W. Troost

Anomalies can be anticipated at the classical level without changing the classical cohomology, by introducing extra degrees of freedom. In the process, the anomaly does not quite disappear. We show that, in fact, it is shifted to new symmetries that come with the extra fields.

R. Machleidt, G. Q. Li

Guided by history, we review the major developments concerning realistic nucleon-nucleon (NN) potentials since the pioneering work by Kuo and Brown on the effective nuclear interaction. Our main emphasis is on the physics underlying various models for the NN interaction developed over the past quarter-century. We comment briefly on how to test the quantitati

Sanjaye Ramgoolam

We show that the Hopf link invariants for an appropriate set of finite dimensional representations of $ U_q SL(2)$ are identical, up to overall normalisation, to the modular S matrix of Kac and Wakimoto for rational $k$ $\widehat {sl(2)}$ representations. We use this observation to construct new modular Hopf algebras, for any root of unity $q=e^{-i\pi m/r}$,

Larry B. Schweitzer

We show that if E is a Frechet G\rtimes S(M)-module, for which the canonical map from the projective completion G\rtimes S(M) {\widehat \otimes} E to E is surjective, then every element of E can be written as a finite sum of elements of the form ae where e\in E and a is an element of the smooth crossed product G\rtimes S(M). We require that the Schwartz func

A. P. Balachandran, G. Bimonte, P. Teotonio-Sobrinho

It is known that the Lagrangian for the edge states of a Chern-Simons theory describes a coadjoint orbit of a Kac-Moody (KM) group with its associated Kirillov symplectic form and group representation. It can also be obtained from a chiral sector of a nonchiral field theory. We study the edge states of the abelian $BF$ system in four dimensions (4d) and show

A. Bilal, I. Kogan

The formula existing in the literature for the ADM mass of 2D dilaton gravity is incomplete. For example, in the case of an infalling matter shockwave this formula fails to give a time-independent mass, unless a very special coordinate system is chosen. We carefully carry out the canonical formulation of 2D dilaton gravity theories (classical, CGHS and RST).

L. DelDebbio, M. Faber, J. Greensite

We point out that the abelian projection theory of quark confinement is in conflict with certain large-N predictions. According to both large-N and lattice strong-coupling arguments, the perimeter law behavior of adjoint Wilson loops at large scales is due to charge-screening, and is suppressed relative to the area term by a factor of $1/N^2$. In the abelian

Peter G. Dodds, T. K. Dodds, Paddy N. Dowling, Christopher J. Lennard

We show that if a rearrangement invariant Banach function space $E$ on the positive semi-axis satisfies a non-trivial lower $q-$ estimate with constant $1$ then the corresponding space $E(\nm)$ of $\tau-$measurable operators, affiliated with an arbitrary semi-finite von Neumann algebra $\nm$ equipped with a distinguished faithful, normal, semi-finite trace $

Beatriz Abadie

Let G and H be two locally compact groups acting on a C*-algebra A by commuting actions. We construct an action on the crossed product AXG out of a unitary 2-cocycle u and the action of H on A. For A commutative, and free and proper actions of G and H, we show that if the roles of these two actions are reversed, and u is replaced by u*, then the correspondin

Beatriz Abadie

By means of techniques from the Morita equivalence theory, we get finitely generated and projective modules over the quantum Heisenberg manifolds. This enables us to get some information about the range of the trace of these algebras, at the level of the K_{0}-group, in terms of the Poisson bracket in whose direction the manifolds are deformed.

Wei Li, Gianfranco Vidali, Ofer Biham

The growth and ordering of a Pb layer deposited on Cu(001) at 150 K has been studied using atom beam scattering. At low coverage, ordered Pb islands with a large square unit cell and nearly hexagonal internal structure are formed. This is a high order commensurate phase with 30 atoms in the unit cell. From the measurement of the island diffraction peak profi

Ofer Aharony

Recently, DiFrancesco and Zuber have characterized the RCFTs which have a description in terms of a fusion potential in one variable, and proposed a generalized potential to describe other theories. In this note we give a simple criterion to determine when such a generalized description is possible. We also determine which RCFTs can be described by a fusion

G. K. Leontaris, J. D. Vergados

We analyse the fermion masses and mixings in the flipped SU(5) model. The fermion mass matrices are evolved from the GUT scale down to $m_W$ by solving the renormalization group equations for the Yukawa couplings. The constraints imposed by the charged fermion data are then utilised to make predictions about the neutrino properties . It is found that the {\i

J. G. Koerner, A. Pilaftsis, K. Schilcher

We analyze possible lepton-flavor-violating decays of the $Z^0$ particle in a minimal extension of the Standard Model, in which one right-handed neutral field for each family has been introduced. Such rare leptonic decays are induced by Majorana neutrinos at the first electroweak loop level and are generally not suppressed by the ordinary "see-saw" mechanism

J. G. Koerner, A. Pilaftsis, K. Schilcher

Leptonic flavor-changing $H^0$ decays with branching ratios of the order of $10^{-5}-10^{-6}$ may constitute an interesting framework when looking for large $CP$-violating effects. We show that leptonic $CP$~asymmetries of an intermediate $H^0$ boson can be fairly large in natural scenarios of the minimal Standard Model ($SM$) with right-handed neutrinos, at

J. A. Gracey

An arbitrary dimensional expression is given for the anomalous dimension of the fermion field in a model with a four point interaction and a $U(1)$ gauge field, at $O(1/N^2)$ within a large flavour expansion in the Landau gauge.

B. Grossmann, M. L. Laursen

We present results for the confinement-deconfinement interface tension $\sigma_{cd}$ of quenched QCD. They were obtained by applying Binder's histogram method to lattices of size $L^2\times L_z\times L_t$ for $L_t=2$ and $L=8,10,12\mbox{ and }14$ and various $L_z\in [L,\, 4\, L]$. The use of a multicanonical algorithm and rectangular geometries have turned o

Wei Chen, Matthew P. A. Fisher, Yong-Shi Wu

We introduce and analyze a lattice model of anyons in a periodic potential and an external magnetic field which exhibits a transition from a Mott insulator to a quantum Hall fluid. The transition is characterized by the anyon statistics, $\alpha$, which can vary between Fermions, $\alpha=0$, and Bosons, $\alpha=1$. For bosons the transition is in the univers

Ben Yu-Kuang Hu, S. Das Sarma

We consider theoretically the electron--electron interaction induced exchange-correlation effects in the lowest subband of a quasi-one-dimensional GaAs quantum wire structures. We calculate, within the leading order dynamical screening approximation ({\em i.e.} the so-called $GW$ approximation of the electron gas theory), the electron self-energy, spectral f

C. A. Stafford, A. J. Millis

We use the Bethe ansatz equations to calculate the charge stiffness $D_{\rm c} = (L/2) d^2 E_0/d\Phi_{\rm c}^2|_{\Phi_{\rm c}=0}$ of the one-dimensional repulsive-interaction Hubbard model for electron densities close to the Mott insulating value of one electron per site ($n=1$), where $E_0$ is the ground state energy, $L$ is the circumference of the system

Sheldon Katz

Mirror symmetry, a phenomenon in superstring theory, has recently been used to give tentative calculations of several numbers in algebraic geometry. In this paper, the numbers of lines and conics on various hypersurfaces which satisfy certain incidence properties are calculated, and shown to agree with the numbers predicted by Greene, Morrison, and Plesser u

Hiromichi Nakazato, Saverio Pascazio

The interaction between an ultrarelativistic particle and a linear array made up of $N$ two-level systems (^^ ^^ AgBr" molecules) is studied by making use of a modified version of the Coleman-Hepp Hamiltonian. Energy-exchange processes between the particle and the molecules are properly taken into account, and the evolution of the total system is calculated

Kingman Cheung

We calculate the gauge-boson pairs $W^-Z$, $W^-\gamma$, $W^+W^-$, $ZZ$ productions in the $e^- \gamma$ collisions, where the photon beam is realized by the laser back-scattering method. These processes are important tests for the non-abelian gauge sector of the standard model (SM). Precise calculations of these processes can therefore probe the anomalous gau

M. Cavaglia' V. de Alfaro, F. de Felice

We discuss the structure of a gravitational euclidean instanton obtained through coupling of gravity to electromagnetism. Its topology at fixed $t$ is $S^1\times S^2$. This euclidean solution can be interpreted as a tunnelling to a hyperbolic space (baby universe) at $t=0$ or alternatively as a static wormhole that joins the two asymptotically flat spaces of

Michael Joyce, Neil Turok

The observed replication of fermions in three families is undoubtedly a reflection of a deeper symmetry underlying the standard model. In this paper we investigate one very elementary possibility, that physics above the grand unification scale is described by the symmetry group $G\timesSU(3)_{fam}$ with $G$ a gauged grand unified group, and $SU(3)_{fam}$ a g

R. N. Mohapatra, X. Zhang

Several misprints in the earlier version (hep-ph/9301286) have been corrected.

M. Bonini, M. D'Attanasio, G. Marchesini

A new proof of perturbative renormalizability and infrared finiteness for a scalar massless theory is obtained from a formulation of renormalized field theory based on the Wilson renormalization group. The loop expansion of the renormalized Green functions is deduced from the Polchinski equation of renormalization group. The resulting Feynman graphs are orga

A. Cappelli, G. V. Dunne, C. A. Trugenberger, G. R. Zemba

The exactness and universality observed in the quantum Hall effect suggests the existence of a symmetry principle underlying Laughlin's theory. We review the role played by the infinite $W_{\infty }$ and conformal algebras as dynamical symmetries of incompressible quantum fluids and show how they predict universal finite-size effects in the excitation spectr

J. R. Espinosa, M. Quirós

We study the electroweak phase transition in the minimal extension of the Standard Model: an extra complex singlet with zero vacuum expectation value. The first-order phase transition is strengthened by the cubic term triggered in the one-loop effective potential by the extra boson. Plasma effects are considered to leading order: they shield the cubic terms

Zhong-Yi LU, Zhao-Bin, SU, Lu YU

Using the valence-bond-solid (VBS) approach and the Schwinger boson mean field approximation, we study the dependence of the Haldane gap of a spin-1 linear chain Heisenberg antiferromagnet on impurity doping with different spins. The impurity spins affect the singlet pairing order parameter $\Delta $ and the constraint factor $\lambda$. As a result, the Hald

H. Krauss, K. Gr"un, T. Rauscher, H. Oberhummer

The astrophysical $S$-factor for the reaction $^7$Be(p,$\gamma$)$^8$B up to an energy of 2~MeV (c.m.) and the capture cross section of $^7$Li(n,$\gamma$)$^8$Li up to 1~MeV (c.m.) are calculated using the Direct Capture model (DC). Both calculations are in good agreement with experimental data.

J. Kripfganz, C. Michael

A lattice approach is developed to measure the sphaleron free energy. Its feasibility is demonstrated through a Monte Carlo study of the two-dimensional O(3) sigma model.

Swapna Mahapatra

A rotating charged black string solution in the low energy effective field theory describing five dimensional heterotic string theory is constructed. The solution is labelled by mass, electric charge, axion charge and angular momentum per unit length. The extremal limit of this solution is also studied.

C. Best, J. M. Eisenberg

Based on the equal-time Wigner function for the Klein-Gordon field, we discuss analytically the mechanism of pair creation in a classical electromagnetic field including back-reaction. It is shown that the equations of motion for the Wigner function can be reduced to a variable-frequency oscillator. The pair-creation rate results then from a calculation anal

Harry. J. Lipkin

CP violation can be observed in B decays when a given process depends upon interference between two weak amplitudes which have different $CP$-violating phases. Since most weak decay diagrams have quark lines where each has a definite flavor label, neutral mesons which are flavor mixtures are particularly interesting. Different diagrams can contribute to the

R. Decker, M. Nowakowski, A. Pilaftsis

We calculate the dominant three body Higgs decays, $H \to W^+W^-(Z^0, \gamma)$ and $H \to t\overline{t}(Z^0,\gamma ,g)$, in the Standard Model. We find that the branching ratios of these decays are of the order of few percent for large Higgs masses. We comment on the behaviour of the partial decay width $\Gamma (H \to t\overline{b}W^-)$ below the $t\overline

Ferruccio Feruglio

The effective lagrangian approach is reviewed and applied to the case of electroweak interactions.

J. A. Gracey

We apply the self consistency method for determining critical exponents to a model with a four fermi interaction coupled to QED and compute various gauge independent exponents in arbitrary dimensions in the large $N$ expansion at $O(1/N)$. The formalism is developed to include a Chern Simons term in three dimensions and the effect such a term has on the expo

Clifford V. Johnson

The integrable structure of open--closed string theories in the $(p,q)$ conformal minimal model backgrounds is presented. The relation between the $\tau$--function of the closed string theory and that of the open--closed string theory is uncovered. The resulting description of the open--closed string theory is shown to fit very naturally into the framework o

W. Melnitchouk, A. W. Thomas

The possible role played by vector mesons in inclusive deep inelastic lepton-nucleon scattering is investigated. In the context of the convolution model, we calculate self-consistently the scaling contribution to the nucleon structure function using the formalism of time-ordered perturbation theory in the infinite momentum frame. Our results indicate potenti

Michael E. Flatte

Recent inelastic-neutron-scattering measurements of a low-energy phonon in Bi_2Sr_2CaCu_2O_8 provide enough information to place a lower bound on the energy gap magnitude at precise locations on the Fermi surface. Measurements of a few low-energy phonons should indicate whether the gap symmetry is d_{x^2-y^2}. Further measurements could map out the angle-res

A. Dolgov Randall

It is shown that the breaking of the conformal invariance in quantum electrodynamics due to the trace anomaly results in the generation of long wave electromagnetic fields during inflationary stage of the universe evolution. If the coefficient of the logarithmic charge renormalization is large (due to a large number of charged particles species), these primo

Michael Leibig

This paper presents a simple ball-and-spring model for the propagation of small amplitude vibrations in a granular material. In this model, the positional disorder in the sample is ignored and the particles are placed on the vertices of a square lattice. The inter-particle forces are modeled as linear springs, with the only disorder in the system coming from

Ming Lu, Mark B. Wise

Microscopic black holes are sensitive to higher dimension operators in the gravitational action. We compute the influence of these operators on the Schwarzschild solution using perturbation theory. All (time reversal invariant) operators of dimension six are included (dimension four operators don't alter the Schwarzschild solution). Corrections to the relati

Leon Takhtajan

We outline the basic principles of canonical formalism for the Nambu mechanics---a generalization of Hamiltonian mechanics proposed by Yoichiro Nambu in 1973. It is based on the notion of Nambu bracket which generalizes the Poisson bracket to the multiple operation of higher order $n \geq 3$ on classical observables and is described by Hambu-Hamilton equatio

Ashok Das, Vishnu Mathur

We investigate the nonleptonic decay of charmed meson into two pseudoscalar mesons using the vector--dominance model, and compare the results with those obtained from the factorization model. In particular, we discuss the role of the annihilation diagrams in the two models.

J. Anandan, C. R. Hagen

The question as to whether neutron acceleration can occur in uniform electromagnetic fields is examined. Although such an effect has been predicted using the canonical equations of motion some doubt has been raised recently as to whether it is in principle observable for a spin 1/2 particle. To resolve this issue a gedanken experiment is proposed and analyze

Patrick J. O'Donnell, Humphrey K. K. Tung

Efforts to predict the rare exclusive decay $B\to K^{\ast}\gamma$ from the well known inclusive decay $b\to s\gamma$ are frustrated by the effect of the large recoil momentum. We show how to reduce the large uncertainty in calculating this decay by relating $B\to K^{\ast}\gamma$ to the semileptonic process $B\to\rho e\bar{\nu}$ using the heavy-quark symmetry

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

We have measured some simple matrix elements for pseudoscalar and vector mesons made of Wilson valence quarks and staggered sea quarks at $\beta=5.6$ at sea quark masses $am_q=0.01$ and 0.025. Our measurements include the decay constants of pseudoscalars (including $f_D$), the wave function at the origin (or decay constant) of vector mesons, and the calculat

E. Abdalla, A. C. V. V. de Siqueira

We consider a string inspired effective Lagrangian for the graviton and dilaton, containing Einstein gravity at the zero slope limit. The numerical solution of the problem shows asymptotically an inflationary universe. The time is measured by the dilaton, as one expects. The result is independent of the introduction of ad-hoc self interactions for the dilato

X. Zhang

Using effective lagrangian, we examine the impacts of new physics on the electroweak baryogenesis. By analysing the high dimensional operators relevent to the Higgs potential we point out that the Higgs mass bound required by electroweak baryogenesis can be relaxed to the region allowed by experiments, provided that new physics appears at the TeV scale.

E. Abdalla, M. C. B. Abdalla, O. H. G. Branco, L. E. Saltini

We derive the current algebra of supersymmetric principal chiral models with a Wess-Zumino term. At the critical point one obtains two commuting super Kac-Moody algebra as expected, but in general there are intertwining fields connecting both right and left sectors, analogously to the bosonic case. Moreover, in the present supersymmetric extension we have a

A. Dobado, J. R. Pelaez

We apply the one-loop results of the $SU(3)_L\times SU(3)_R$ ChPT suplemented with the inverse amplitude method to fit the available experimental data on $\pi\pi$ and $\pi K$ scattering. With esentially only three parameters we describe accurately data corresponding to six different channels, namely $(I,J)=(0,0), (2,0), (1,1), (1/2,0), (3/2,0)$ and $(1/2,1)$

C. Best, P. Gornicki, W. Greiner

The formalism based on the equal-time Wigner function of the two-point correlation function for a quantized Klein--Gordon field is presented. The notion of the gauge-invariant Wigner transform is introduced and equations for the corresponding phase-space calculus are formulated. The equations of motion governing the Wigner function of the Klein--Gordon field

Claudio Coriano', Anatoly Radyushkin, George Sterman

We extend QCD sum rule analysis to moderate energy fixed angle Compton scattering. In this kinematic region there is a strong similarity to the sum rule treatment of electromagnetic form factors, although the four-point amplitude requires a modification of the Borel transform. To illustrate our method, we derive the sum rules for helicity amplitudes in pion

Niclas Engberg, Bengt E. W Nilsson, Per Sundell

We perform the sewing of two (dual) Ramond reggeon vertices and derive an algorithm by means of which the so obtained four-Ramond reggeon vertex may be explicitly computed at arbitrary oscillator (mass) level. A closed form of the four-vertex is then deduced on the basis of a comparison to all terms obtained by sewing that contain only level zero and one osc

C. Pich, F. Schwabl

The question of the existence of order in two-dimensional isotropic dipolar Heisenberg antiferromagnets is studied. It is shown that the dipolar interaction leads to a gap in the spin-wave energy and a nonvanishing order parameter. The resulting finite N\'eel-temperature is calculated for a square lattice by means of linear spin-wave theory.

A. Pilaftsis, M. Nowakowski

We study $CP$ violation in the process $e^+e^- \to t\bar{t} \nu\bar{\nu}$ at an $e^+e^-$-TeV collider. As the source of $CP$ violation we assume a two-Higgs doublet model with an explicitly $CP$-noninvariant Higgs potential. Sizeable $CP$-odd observables originating from the subprocess reaction, $W^+W^- \to t\bar{t}$, may arise as a result of finite width ef

G. Cvetic, M. Nowakowski, A. Pilaftsis

We formulate the conditions under which a purely bosonic theory (without fermions) containing neutral spin-0 particles and vector (gauge) bosons violates the CP-symmetry through the presence of CP-even and CP-odd operators in the Lagrangian. This is done without reference to explicitly CP-violating scalar sector of extended standard models (SM) with two or m

Harry J. Lipkin

Sum rules originally derived for the M\"ossbauer Effect are applied to weak semileptonic B decays. The sum rules follow from assuming that the decay by electroweak boson emission of an unstable nucleus or heavy quark in a bound system is described by a pointlike coupling to a current which acts only on the decaying object, that the Hamiltonian of the bound s

M. Reuter, N. Tetradis, C. Wetterich

We study, with various methods (standard large N evaluation of the functional integral for the effective potential, solution of the Schwinger-Dyson equations), the high temperature phase transition for the $N$-component $\phi^4$ theory in the large $N$ limit. Our results fully confirm a previous investigation of the problem, for arbitrary $N$, with the metho

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

The structure of one-loop divergences of two-dimensional dilaton-Maxwell quantum gravity is investigated in two formalisms: one using a convenient effective action and the other a unique effective action. The one-loop divergences (including surface divergences) of the convenient effective action are calculated in three different covariant gauges: (i) De Witt

Kimyeong Lee

We study four dimensional systems of global, axionic and local strings. By using the path integral formalism, we derive the dual formulation of these systems, where Goldstone bosons, axions and missive vector bosons are described by antisymmetric tensor fields, and strings appear as a source for these tensor fields. We show also how magnetic monopoles attach

S. Chaudhuri, D. Minic

The classical black hole background of two-dimensional string theory is examined after including the effect of the tachyon field. Keeping all terms upto $O(T^2)$, and making no other approximations, the only consistent classical solution to the resulting dilaton-graviton theory is found to be flat spacetime with a nontrivial dilaton.

V. M. Belyaev

A method for nonperturbative path integral calculation is proposed. Quantum mechanics as a simplest example of a quantum field theory is considered. All modes are decomposed into hard (with frequencies $\omega^2 >\omega^2_0$) and soft (with frequencies $\omega^2 <\omega^2_0$) ones, $\omega_0$ is a some parameter. Hard modes contribution is considered by weak

G. Bhanot, M. Creutz, U. Glassner, I. Horvath

On simple cubic lattices, we compute low temperature series expansions for the energy, magnetization and susceptibility of the three-state Potts model in D=2 and D=3 to 45 and 39 excited bonds respectively, and the eight-state Potts model in D=2 to 25 excited bonds. We use a recursive procedure which enumerates states explicitly. We analyze the series using

J. Harnad, M. -A. Wisse

A class of Poisson embeddings of reduced, finite dimensional symplectic vector spaces into the dual space $\Lg_R^*$ of a loop algebra, with Lie Poisson structure determined by the classical split $R$--matrix $R=P_+ - P_-$ is introduced. These may be viewed as equivariant moment maps inducing natural Hamiltonian actions of the ``dual'' group $\LG_R = \LGp \ti

J. Alfaro, P. H. Damgaard

The antifields of the Batalin-Vilkovisky Lagrangian quantization are standard antighosts of certain collective fields. These collective fields ensure that Schwinger-Dyson equations are satisfied as a consequence of the gauge symmetry algebra. The associated antibracket and its canonical structure appear naturally if one integrates out the corresponding ghost

Alon E. Faraggi

I discuss gauge coupling unification in a class of superstring standard--like models, which are derived in the free fermionic formulation. Recent calculations indicate that the superstring unification scale is at $O(10^{18}GeV)$ while the minimal supersymmetric standard model is consistent with LEP data if the unification scale is at $O(10^{16})GeV$. A gener

R. G. Roberts, L. Roszkowski

We examine various predictions of the minimal supersymmetric standard model coupled to minimal supergravity. The model is characterised by a small set of parameters at the unification scale. The supersymmetric particle spectrum at low energy and the spontaneous breaking of the standard model itself are then generated radiatively. The previously considered pr

Domenico Giulini

The configuration-space topology in canonical General Relativity depends on the choice of the initial data 3-manifold. If the latter is represented as a connected sum of prime 3-manifolds, the topology receives contributions from all configuration spaces associated to each individual prime factor. There are by now strong results available concerning the diff

Domenico Giulini

We consider the configuration space of the Skyrme model and give a simple proof that loops generated by full spatial rotations are contractible in the even-, and non-contractible in the odd-winding-number sectors.

Erich R. Poppitz

The electroweak vacuum structure in an external magnetic field close to the lower critical value is considered at finite fermion density. It is shown that the leading effect of the fermions is to reduce the symmetry of the W-pair condensate in the direction of the magnetic field. The energy is minimized by the appearance of a helicoidal structure of the cond

D. Chang, W. -Y. Keung

We investigate a potentially large CP violating asymmetry in the neutral Higgs boson decay into a heavy quark pair or a $W^+$--$W^-$ pair. The source of the CP nonconservation is in the Yukawa couplings of the Higgs boson which can contain both scalar and pseudoscalar pieces. One of the interesting consequence is the different rates of the Higgs boson decays

Alberto Lerda, Stefano Sciuto

Anyonic oscillators with fractional statistics are built on a two-dimensional square lattice by means of a generalized Jordan-Wigner construction, and their deformed commutation relations are thoroughly discussed. Such anyonic oscillators, which are non-local objects that must not be confused with $q$-oscillators, are then combined \`a la Schwinger to constr

Y. Fujiwara, H. Ishihara, H. Kodama

We show several kinematical properties that are intrinsic to the Bianchi models with compact spatial sections. Especially, with spacelike hypersurfaces being closed, (A) no anisotropic expansion is allowed for Bianchi type V and VII(A\not=0), and (B) type IV and VI(A\not=0,1) does not exist. In order to show them, we put into geometric terms what is meant by

H. Lu, C. N. Pope, S. Schrans, X. J. Wang

We present a detailed investigation of scattering processes in $W_3$ string theory. We discover further physical states with continuous momentum, which involve excitations of the ghosts as well as the matter, and use them to gain a better understanding of the interacting theory. The scattering amplitudes display factorisation properties, with states from the

V. E. Korepin, A. G. Izergin, N. M. Bogoliubov

The book contain detailed explanation of Bethe Ansatz, Quantum Inverse Scattering Method and Algebraic Bether Ansatz as well. Main Models are Nonlinear Schrodinger equation (one dimensional Bose gas), Sine-Gordon and Thiring models. Heisenberg Antiferromagnet and Hubbard models. It is explained in detail, how to calculate correlation functions.

Rajan Gupta, Apoorva Patel, Stephen Sharpe

We present an exploratory calculation of the $I=2$ $\pi-\pi$ scattering amplitude at threshold using Wilson fermions in the quenched approximation, including all the required contractions. We find good agreement with the predictions of chiral perturbation theory even for pions of mass 560-700 MeV. Within the 10\% errors, we do not see the onset of the bad ch

Martin A. Guest

Let $X$ be a compact toric variety. Let $Hol$ denote the space of based holomorphic maps from $CP^1$ to $X$ which lie in a fixed homotopy class. Let $Map$ denote the corresponding space of continuous maps. We show that $Hol$ has the same homotopy groups as $Map$ up to some (computable) dimension. The proof uses a description of $Hol$ as a space of configurat

Ch. Devchand, A. N. Leznov

We present a B\"acklund transformation (a discrete symmetry transformation) for the self-duality equations for supersymmetric gauge theories in N-extended super-Minkowski space ${\cal M}^{4|4N}$ for an arbitrary semisimple gauge group. For the case of an $A_1$ gauge algebra we integrate the transformation starting with a given solution and iterating the proc

H. Hata, B. Zwiebach

We investigate the variation of the string field action under changes of the string field vertices giving rise to different decompositions of the moduli spaces of Riemann surfaces. We establish that any such change in the string action arises from a field transformation canonical with respect to the Batalin-Vilkovisky (BV) antibracket, and find the explicit

Chang-Pu Sun, Mo-Lin Ge

In this paper a new quasi-triangular Hopf algebra as the quantum double of the Heisenberg-Weyl algebra is presented.Its universal R-matrix is built and the corresponding representation theory are studied with the explict construction for the representations of this quantum double. \newpage

Antimo Angelucci, Sandro Sorella

We investigate the phase diagram of the two dimensional {\it t}-{\it J} model using a recently developed technique that allows to solve the mean-field model hamiltonian with a variational calculation. The accuracy of our estimate is controlled by means of a small parameter $1/q$, analogous to the inverse spin magnitude $1/s$ employed in studying quantum spin

Larry B. Schweitzer

The author's recent results on spectral invariant dense subalgebras of C*-algebras associated with dynamical systems are summarized. If G is a compactly generated polynomial growth Type R Lie group, and the action of G on S(M) (Schwartz functions on a locally compact G-space M) is tempered in a certain sense, then there is a natural smooth crossed product S(

Eric Bedford, Mikhail Lyubich, John Smillie

This paper deals with the dynamics of a simple family of holomorphic diffeomorphisms of $\C^2$: the polynomial automorphisms. This family of maps has been studied by a number of authors. We refer to [BLS] for a general introduction to this class of dynamical systems. An interesting object from the point of view of potential theory is the equilibrium measure