July 1992 arXiv papers — page 2

Claude Bernard, Michael C. Ogilvie, Thomas A. DeGrand, Carleton DeTar

We report on a study of hadron thermodynamics with two flavors of Wilson quarks on 12^3x6 lattices. We have studied the crossover between the high and low temperature regimes for three values of the hopping parameter, kappa=0.16, 0.17, and 0.18. At each of these values of kappa we have carried out spectrum calculations on 12^3x24 lattices for two values of t

Urs M. Heller, Herbert Neuberger, Pavlos Vranas

We calculate the triviality bound on the Higgs mass in scalar field theory models whose global symmetry group $SU(2)_L \times SU(2)_{\rm custodial} \approx O(4)$ has been replaced by $O(N)$ and $N$ has been taken to infinity. Limits on observable cutoff effects at four percent in several regularized models with tunable couplings in the bare action yield triv

T. Damour, S. Deser, J. McCarthy

Motivated by the apparent dependence of string $σ$--models on the sum of spacetime metric and antisymmetric tensor fields, we reconsider gravity theories constructed from a nonsymmetric metric. We first show that all such "geometrical" theories homogeneous in second derivatives violate standard physical requirements: ghost-freedom, absence of algebra

Boris Kastening

The renormalization group is used to improve the effective potential of massive ${\rm O}(N)$ symmetric $ϕ^4$ theory. Explicit results are given at the two-loop level.

David Kastor, Jennie Traschen

Hopefully tex-able version.

Jan Govaerts

Canonical quantisation of rigid particles is considered paying special attention to the restriction on phase space due to causal propagation. A mixed Lorentz-gravitational anomaly is found in the commutator of Lorentz boosts with world-line reparametrisations. The subspace of gauge invariant physical states is therefore not invariant under Lorentz transforma

Fouad Chaatit

We prove that if X is an infinite dimensional Banach lattice with a weak unit then there exists a probability space (Omega, Sigma,mu) so that the unit sphere S(L_1(Omega, Sigma, mu) is uniformly homeomorphic to the unit sphere S(X) if and only if X does not contain l_{infty}^n's uniformly.

Edward Odell, Haskell P. Rosenthal, Thomas Schlumprecht

In this paper we show that every sequence (F_n) of finite dimensional subspaces of a real or complex Banach space with increasing dimensions can be ``refined'' to yield an F.D.D. (G_n), still having increasing dimensions, so that either every bounded sequence (x_n), with x_n in G_n for n in N, is weakly null, or every normalized sequence (x_n), with

F. Ravanini, R. Tateo, A. Valleriani

We propose the factorizable S-matrices of the massive excitations of the non-unitary minimal model $M_{2,11}$ perturbed by the operator $Φ_{1,4}$. The massive excitations and the whole set of two particle S-matrices of the theory is simply related to the $E_8$ unitary minimal scattering theory. The counting argument and the Thermodynamic Bethe Ansatz (TBA) a

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

We construct the BRST operator for non-critical $W_3$-strings and discuss the tachyon-like spectrum. For $N$-punctured spheres with $N \leq 5$ we briefly describe a formal definition of the integral over $W_3$-moduli space.

D. Harley, TK Kuo, J. Pantaleone

The recent 71Ga solar neutrino observation is combined with the 37Cl and Kamiokande-II observations in an analysis for neutrino masses and mixings. The allowed parameter region is found for matter enhanced mixings among all three neutrino flavors. Distortions of the solar neutrino spectrum unique to three flavors are possible and may be observed in continuin

T. Barnes, E. S. Swanson, J. Weinstein

We study $I=3/2$ elastic $Kπ$ scattering to Born order using nonrelativistic quark wavefunctions in a constituent-exchange model. This channel is ideal for the study of nonresonant meson-meson scattering amplitudes since s-channel resonances do not contribute significantly. Standard quark model parameters yield good agreement with the measured S- and P-wave

A. Zhitnitsky

Two different but tightly connected problems, $U(1)$ and strong CP violation problems, are discussed in two different models which exhibit both asymptotic freedom and confinement. One of them is the 3d Polyakov's model of compact QED and the other is 4d gluodynamics. It is shown that although both these models possess the long range interactions of the t

B. A. Berg, T. Celik

We report a Monte Carlo simulation of the $2D$ Edwards-Anderson spin glass model within the recently introduced multicanonical ensemble. Replica on lattices of size $L^2$ up to $L=48$ are investigated. Once a true groundstate is found, we are able to give a lower bound on the number of statistically independent groundstates sampled. Temperature dependence of

C. F. Baillie, D. A. Johnston

We investigate the crossover between weak and strong self-avoidance in a simulation of random surfaces with extrinsic curvature. We consider both dynamically triangulated and rigid surfaces with the two possible discretizations of the extrinsic curvature term.

C. Frick, L. Lin, I. Montvay, G. Munster

An exploratory numerical study of the influence of heavy fermion doublets on the mass of the Higgs boson is performed in the decoupling limit of a chiral $\rm SU(2)_L \otimes SU(2)_R$ symmetric Yukawa model with mirror fermions. The behaviour of fermion and boson masses is investigated at infinite bare quartic coupling on $4^3 \cdot 8$, $6^3 \cdot 12$ and $8

Riccardo Capovilla, Ted Jacobson

In the derivation of a pure spin connection action functional for gravity two methods have been proposed. The first starts from a first order lagrangian formulation, the second from a hamiltonian formulation. In this note we show that they lead to identical results for the specific cases of pure gravity with or without a cosmological constant.

S. Dalley, I. Klebanov

We study the large $N$ limit of an interacting \td\ matrix field theory, whose perturbative expansion generates the sum over planar random graphs embedded in two dimensions. In the \lc\ quantization the theory possesses closed string excitations which become free as $N\to\infty$. If the longitudinal momenta are discretized, then the calculation of the free s

G. Papadopoulos, B. Spence

We present a new parametrisation of the space of solutions of the Wess-Zumino-Witten model on a cylinder, with target space a compact, connected Lie group G. Using the covariant canonical approach the phase space of the theory is shown to be the co-tangent bundle of the loop group of the Lie group G, in agreement with the result from the Hamiltonian approach

David Kutasov

We argue that the torus partition sum in $2d$ (super) gravity, which counts physical states in the theory, is a decreasing function of the renormalization group scale. As an application we chart the space of $(\hat c\leq1)$ $c\leq1$ models coupled to (super) gravity, confirming and extending ideas due to A. Zamolodchikov, and discuss briefly string theory, w

Norisuke Sakai, Yoshiaki Tanii

States in the absolute (semi-relative) cohomology but not in the relative cohomology are examined through the component decomposition of the string field theory action for the 2-D string. It is found that they are auxiliary fields without kinetic terms, but are important for instance in the master equation for the Ward-Takahashi identities. The ghost structu

V. Barger, R. J. N. Phillips, K. Whisnant

The recently reported solar neutrino signal in the $^{71}$Ga GALLEX detector adds a new dimension to the solar neutrino puzzle, complementing the previously known signals in $^{37}$Cl and water-Cherenkov detectors. Possible explanations for this new signal in terms of matter-enhanced neutrino oscillations (MSW effect) are already awaiting in the literature.

R. Sekhar Chivukula, M. Dugan, M. Golden

Radiative corrections to electroweak parameters in technicolor theories may be evaluated by one of two techniques: either one estimates spectral function integrals using scaled QCD data, or one uses naive dimensional analysis with a chiral Lagrangian. The former yields corrections to electroweak parameters proportional to the number of flavors and the number

Amitava Datta

It is argued with the help of an illustrative model, that the inter--species hierarchy among the fermion masses and the quark mixing angles can be accommodated naturally in the standard model with (approximate) flavor democracy provided there are four families of sequential quark--leptons with all members of the fourth family having roughly equal masses. The

R. K. Schaefer, Q. Shafi

The simplest realizations of the new inflationary scenario typically give rise to primordial density fluctuations which deviate logarithmically from the scale free Harrison - Zeldovich spectrum. We consider a number of such examples and, in each case we normalize the amplitude of the fluctuations with the recent COBE measurement of the microwave background a

I. J. R. Aitchison, N. Dorey, M. Klein-Kreisler, N. E. Mavromatos

Dynamical symmetry breaking in three-dimensional QED with N fermion flavours is considered at finite temperature, in the large $N$ approximation. Using an approximate treatment of the Schwinger-Dyson equation for the fermion self-energy, we find that chiral symmetry is restored above a certain critical temperature which depends itself on $N$. We find that th

J. Ambjorn, K. Farakos

By numerical simulations in {\it real time} we provide evidence in favour of sphaleron like transitions in the hot, symmetric phase of the electroweak theory. Earlier performed observations of a change in the Chern-Simons number are supplemented with a measurement of the lowest eigenvalues of the three-dimensional staggered fermion Dirac operator and observa

Riccardo Capovilla

The non-minimal coupling of a scalar field is considered in the framework of Ashtekar's new variables formulation of gravity. A first order action functional for this system is derived in which the field variables are a tetrad field, and an SL(2,C) connection, together with the scalar field. The tetrad field and the SL(2,C) connection are related to the

Selman Hershfield, John H. Davies, Per Hyldgaard, Christopher J. Stanton

We compute the zero frequency current noise numerically and in several limits analytically for the coulomb blockade problem consisting of two tunnel junctions connected in series. At low temperatures over a wide range of voltages, capacitances, and resistances it is shown that the noise measures the variance in the number of electrons in the region between t

Ole H. Nielsen, James P. Sethna, Per Stoltze, Karsten W. Jacobsen

We simulate the melting of a 71 A diameter cluster of Cu. At low temperatures the crystal exhibits facets. With increasing temperatures the open facets pre-melt, the melted regions coalesce into a liquid envelope containing a crystalline nucleus, and the nucleus finally goes unstable to the supercooled liquid. Using critical droplet theory and experimental d

M. Hasenbusch, M. Marcu, K. Pinn

We verify the Kosterlitz Thouless scenario for three different SOS (solid-on-solid) models, including the dual transforms of XY-models with Villain and with cosine action. The method is based on a matching of the renormalization group (RG) flow of the candidate models with the flow of a bona fide KT model, the exactly solvable BCSOS model. We obtain high pre

M. Hasenbusch, G. Lana, M. Marcu, K. Pinn

We adapt the VMR (valleys-to-mountains reflections) algorithm, originally devised by us for simulations of SOS models, to the BCSOS model. It is the first time that a cluster algorithm is used for a model with constraints. The performance of this new algorithm is studied in detail in both phases of the model, including a finite size scaling analysis of the a

Sinya Aoki

We consider fermion-gauge couplings in the Wilson-Yukawa approach for lattice chiral gauge theories. At the leading order of a fermionic hopping parameter expansion we find that the fermion-gauge coupling has a chiral and tree-like structure. We argue that this fermion-gauge coupling remains non-zero in the continuum limit taken in the Higgs phase. Possible

Anna Hasenfratz, Peter Hasenfratz

We investigate the detailed conditions under which a purely fermionic model with current-current interaction goes over to a renormalizable, asymptotically free SU$(N)$ gauge theory.

Thomas Kalkreuter

Practical modifications of deterministic multigrid and conventional relaxation algorithms are discussed. New parameters need not be tuned but are determined by the algorithms themselves. One modification can be thought of as ``updating on a last layer consisting of a single site''. It eliminates critical slowing down in computations of bosonic and fermionic

Fred Adams, J. R. Bond, Katherine Freese, Joshua Frieman

A pseudo-Nambu-Goldstone boson, with a potential of the form $V(ϕ) = Λ^4[1 \pm \cos(ϕ/f)], naturally gives rise to inflation if $f \sim M_{Pl}$ and $Λ\sim M_{GUT}$. We show how this can arise in technicolor-like and superstring models, and work out an explicit string example in the context of multiple gaugino condensation models. We study the cosmology of th

S. K. Yip, J. A. Sauls

Recent theories of the NMR in the CuO superconductors are based on a spin-singlet $d_{x^2-y^2}$ order parameter. Since this state has nodal lines on the Fermi surface, nonlinear effects associated with low-energy quasiparticles become important, particularly at low temperatures. We show that the field-dependence of the supercurrent, below the nucleation fiel

C. Ting

We show that the notion of mutual statistics arises naturally from the representation theory of the braid group over the multi-sheeted surface. A Hamiltonian which describes particles moving on the double-sheeted surface is proposed as a model for the bilayered fractional quantum Hall effect (FQHE) discovered recently. We explicitly show that the quasi-holes

C. Ting

The braid group dynamics captures the fractional quantum Hall effect (FQHE) as a manifestation of puncture phase. When the dynamics is generalized for particles on a multi-sheeted surface, we obtain new tools which determine the fractional charges, the quantum statistics, and the filling factors of the multi-layered FQHE. A many-quasi-hole wavefunction is pr

A. A. Migdal

We study the 1/N expansion in the recently proposed model of the lattice gauge theory induced by heavy scalar field in adjoint representation. In the first approximation the fluctuations of the density of eigenvalues of the scalar field are Gaussian, so that the scalar glueball spectrum is defined from the corresponding linear wave equation.

Lay Nam Chang, Chopin Soo

We show that all solutions to the vacuum Einstein field equations may be mapped to instanton configurations of the Ashtekar variables. These solutions are characterized by properties of the moduli space of the instantons. We exhibit explicit forms of these configurations for several well-known solutions, and indicate a systematic way to get new ones. Some in

J. R. Bienkowska, H. Lu

In this note we investigate the generalised critical $N=2$ superstrings in $(1,2p)$ spacetime signature. We calculate the four-point functions for the tachyon operators of these theories. In contrast to the usual $N=2$ superstring in $(2,2)$ spacetime, the four-point functions do not vanish. The exchanged particles of the four-point function are included in

C. P. Constantinidis, L. A. Ferreira, J. F. Gomes, A. H. Zimerman

It is shown that the Affine Toda models (AT) constitute a ``gauge fixed'' version of the Conformal Affine Toda model (CAT). This result enables one to map every solution of the AT models into an infinite number of solutions of the corresponding CAT models, each one associated to a point of the orbit of the conformal group. The Hirota's $τ$-functi

M. J. Duff, J. X. Lu

We re-examine the classification of supersymmetric extended objects in the light of the recently discovered Type II p-branes, previously thought not to exist for p> 1. We find new points on the brane-scan only in D = 10 and then only for p = 3(Type IIB), p = 4 (Type IIA), p = 5 (Type IIA and IIB) and p = 6 (Type IIA). The case D = 10, p = 2 (Type IIA) also e

A. Carlini, A. Treves, F. Fucito, M. Martellini

We consider the effect of vacuum polarization around the horizon of a 4 dimensional axionic stringy black hole. In the extreme degenerate limit ($Q_a=M$), the lower limit on the black hole mass for avoiding the polarization of the surrounding medium is $M\gg (10^{-15}÷10^{-11})m_p$ ($m_p$ is the proton mass), according to the assumed value of the axion mass

Sudhakar Panda, Shibaji Roy

Additional symmetries of the $p$-reduced KP hierarchy are generated by the Lax operator $L$ and another operator $M$, satisfying $res (M^n L^{m+n/p})$ = 0 for $1 \leq n \leq p-1$ and $m \geq -1$ with the condition that ${\partial L \over {\partial t_{kp}}}$ = 0, $k$ = 1, 2,..... We show explicitly that the generators of these additional symmetries satisfy a

David P. Bennett, Sun Hong Rhie

We report on a calculation of large scale anisotropy in the cosmic microwave background radiation in the global monopole and texture models for cosmic structure formation. We have evolved the six component linear gravitational field along with the monopole or texture scalar fields numerically in an expanding universe and performed the Sachs-Wolfe integrals d

Lawrence M. Krauss

Comparison of theobservedanisotropy with that predicted iadiabaticDM models suggest that much of thserved signal may be due to long wavelenh gravitational waves. In inflationary models this requires the generation of tensor fluctuations to be at least comparable to scalar density fltuations. This i is feasible, but depends sensitively on the inflaton potenti

Walter Wilcox

A numerical investigation of time-separated charge overlap measurements is carried out for the pion in the context of lattice QCD using smeared Wilson fermions. The evolution of the charge distribution function is examined and the expected asymptotic time behavior $\sim e^{-(E_{q}-m_π)t}$, where $t$ represents the charge density relative time separation, is

R. Ibanez-Meier, P. M. Stevenson

Branchina et al and Consoli have recently shown that the one-loop effective potential (1LEP) of massless lambda-phi**4 theory can be renormalized in two distinct ways. One of these is the conventional renormalization of Coleman and Weinberg. The other requires an infinite wavefunction renormalization, and is very similar to the "autonomous" renormali

Ashoke Sen

The electric-magnetic duality transformation in four dimensional heterotic string theory discussed by Shapere, Trivedi and Wilczek is shown to be an exact symmetry of the equations of motion of low energy effective field theory even after including the scalar and the vector fields, arising due to compactification, in the effective field theory. Using this du

Parthasarathi Majumdar

We discuss Inönü-Wigner contractions of affine Kac-Moody algebras. We show that the Sugawara construction for the contracted affine algebra exists only for a fixed value of the level $k$, which is determined in terms of the dimension of the uncontracted part of the starting Lie algebra, and the quadratic Casimir in the adjoint representation. Further, we dis

N. Dorey, P. S. Kurzepa

We consider a soluble model of large $ϕ^{4}$-graphs randomly embedded in one compactified dimension; namely the large-order behaviour of finite-temperature perturbation theory for the partition function of the anharmonic oscillator. We solve the model using semi-classical methods and demonstrate the existence of a critical temperature at which the system und

David G. Boulware

Gott spacetime has closed timelike curves, but no locally anomalous stress-energy. A complete orthonormal set of eigenfunctions of the wave operator is found in the special case of a spacetime in which the total deficit angle is $2π$. A scalar quantum field theory is constructed using these eigenfunctions. The resultant interacting quantum field theory is no

Jean-Rene Cudell, Keith R. Dienes

All available data indicate a surplus of baryon states over meson states for energies greater than about 1.5 GeV. Since hadron-scale string theory suggests that their numbers should become equal with increasing energy, it has recently been proposed that there must exist exotic mesons with masses just above 1.7 GeV in order to fill the deficit. We demonstrate

L. Clavelli, P. W. Coulter, B. Fenyi, C. Hester

We investigate the possibility that the difference between the measurements of $α_3(M_Z)$ from the hadronic branching ratio of the $Z^0$ and the world average of other measurements is due to the decay of the $Z^0$ into quark, anti-squark, and gluino. Consequences for supersymmetry breaking models are discussed.

N. Schultka, M. Müller-Preussker

The topological vacuum structure of the two-dimensional $~CP^{n-1}~$ model for $~n = 3,5,7~$ is studied on the lattice. In particular we investigate the small-volume limit on the torus as well as on the sphere and compare with continuum results. For $~n \ge 5~$ , where lattice artifacts should be suppressed, the topological susceptibility shows unexpectedly

M. Goeckeler, G. Schierholz

We describe a method for evaluating chiral gauge theories that is not plagued by the doubling problem. To demonstrate the efficiency of the approach, we apply our ideas to the chiral Schwinger model.

Alan T. Dorsey

Vortex motion in type II superconductors is studied starting from a variant of the time dependent Ginzburg-Landau equations, in which the order parameter relaxation time is taken to be complex. Using a method due to Gor'kov and Kopnin, we derive an equation of motion for a single vortex ($B\ll H_{c2}$) in the presence of an applied transport current. The

Robert J. Troy, Alan T. Dorsey

We study the flux-flow Hall effect and thermomagnetic transport near the upper critical field \hctwo\ in extreme type-II superconductors starting from a suitable generalization of the time dependent Ginzburg-Landau equations. We explicitly incorporate the effects of backflow into the calculations of the local electric field and current, leading to a current

Matthias Troyer, Diethelm Würtz

The one dimensional Kondo lattice model is investigated using Quantum Monte Carlo and transfer matrix techniques. In the strong coupling region ferromagnetic ordering is found even at large band fillings. In the weak coupling region the system shows an RKKY like behavior.

V. Privman, M. D. Grynberg

We derive an improved mean-field approximation for k-body annihilation reactions kA --> inert, for hard-core diffusing particles on a line, annihilating in groups of k neighbors with probability 0 < q <= 1. The hopping and annihilation processes are correlated to mimic chemical reactions. Our new mean-field theory accounts for hard-core particle properties a

B. D. Lubachevsky, V. Privman, S. C. Roy

We report numerical simulation of the deposition of spherical particles on a planar surface, by ballistic, straight-line trajectory transport, and assuming irreversible adhesion on contact with the surface or previously deposited particles. Our data indicate that the deposit formed has a loosely layered structure within few diameters from the surface. This s

B. Blok, M. Shifman

We continue to investigate the effects of the (dominant) subleading operator of the $\vecσ\vec H$ type in the $1/N_c$ parts of the weak nonleptonic amplitudes. If the previous work concentrated on exclusive decays now we analyse inclusive widths in a certain kinematic limit. Deviations from the parton model predictions are found due to soft-gluon color excha

Michael Dine

We consider some questions of naturalness which arise when one considers conventional field theories in the presence of gravitation: the problem of global symmetries, the strong CP problem, and the cosmological constant problem. Using string theory as a model, we argue that it is reasonable to postulate weakly broken global discrete symmetries. We review the

O. F. Dayi

A systematic way of formulating the Batalin-Vilkovisky method of quantization was obtained in terms of the ``odd time&#39;&#39; formulation. We show that in a class of gauge theories it is possible to find an ``odd time lagrangian&#39;&#39; yielding, by a Legendre transformation, an ``odd time hamiltonian&#39;&#39; which is the minimal solution of the master

B. Sathiapalan

We derive an expression in closed form for the action of a finite element of the Virasoro Group on generalized vertex operators. This complements earlier results giving an algorithm to compute the action of a finite string of generators of the Virasoro Algebra on generalized vertex operators. The main new idea is to use a first order formalism to represent t

F. Delduc, A. Galperin, P. Howe, E. Sokatchev

We propose a new formulation of the heterotic $D=10$ Green-Schwarz superstring whose worldsheet is a superspace with two even and eight odd coordinates. The action is manifestly invariant under both target-space supersymmetry and a worldsheet reparametrisation supergroup. It contains only a finite set of auxiliary fields. The key ingredient are the commuting

J. Erler, D. Jungnickel, M. Spalinski, S. Stieberger

We derive the basic correlation functions of twist fields coming from arbitrary twisted sectors in symmetric $Z_N$ orbifold conformal field theories, keeping all the admissible marginal perturbations, in particular those corresponding to the antisymmetric tensor background field. This allows a thorough investigation of modular symmetries in this type of stri

Emil Nissimov, Svetlana Pacheva

A brief review is given of an adaptation of the coadjoint orbit method appropriate for study of models with infinite-dimensional symmetry groups. It is illustrated on several examples, including derivation of the WZNW action of induced $D=2\,$ $(N,0)\,$ supergravity. As a main application, we present the geometric action on a generic coadjoint orbit of the d

Alexios P. Polychronakos, Rodanthy Tzani

A new quantum mechanical wave equation describing a particle with frictional forces is derived. It depends on a parameter $α$ whose range is determined by the coefficient of friction $γ$, that is, $0 \leq α\leq γ$. For one extreme value of this parameter, $α= 0$, we recover Kostin&#39;s equation. For the other extreme value, $α= γ$, we obtain an equation in

E. Elizalde, S. D. Odintsov

The quantum properties of two-dimensional matter-dilaton gravity ---which includes a large family of actions for two-dimensional gravity (in particular, string-inspired models)--- are investigated. The one-loop divergences in linear covariant gauges are calculated and the structure of the one-loop renormalization is studied. The explicit forms of the dilaton

Martin White

We present an in depth discussion of the production of gravitational waves from an inflationary phase that could have occurred in the early universe, giving derivations for the resulting spectrum and energy density. We also consider the large-scale anisotropy in the cosmic microwave background radiation coming from these waves. Assuming that the observed qua

A. Zhitnitsky

We discuss a few tightly connected problems, such as the $U(1)$ problem, confinement, the $θ$ -dependence within a framework of the dynamical toron approach. We calculate two fundamental characteristics of the theory: the vacuum expectation value (vev) of the Wilson loop and the topological susceptibility. The analogy with well known 2+1 dimensional QED whic

J. Ellis, J. Lopez, D. Nanopoulos

The most natural MSW neutrino oscillation interpretation of the GALLEX and other solar neutrino data, which invokes $m_{ν_μ}\sim3\times10^{-3}\eV$, and a general GUT see-saw hierarchy of neutrino masses, $m_{ν_{e,μ,τ}}\sim (m_{u,c,t})^2/M_U$, suggest that $m_{ν_τ}\sim10\eV$ in agreement with the preference of COBE and other data on large-scale structure in t

Alexander Moroz

Recently it has been suggested by A. M. Tsvelik that quantum S=1/2 antiferromagnet can be described by the Majorana fermions in an irreducible way and without any constraint. In contrast to this claim we shall show that this representation is highly reducible. It is a direct sum of four irreducible fundamental representations of $su(2)$ algebra.

Wei Chen, Miao Li

Corrected with some rewording

W. Siegel

As open N=2 or 4 strings describe self-dual N=4 super Yang-Mills in 2+2 dimensions, the corresponding closed (heterotic) strings describe self-dual ungauged (gauged) N=8 supergravity. These theories are conveniently formulated in a chiral superspace with general supercoordinate and local OSp(8|2) gauge invariances. The super-light-cone and covariant-componen

Sergei V. Ketov, Hitoshi Nishino, S. James Gates,

We study supersymmetry and self-duality in a four-dimensional space-time with the signature (2,2), that we call the Atiyah-Ward space-time. Dirac matrices and spinors, in particular Majorana-Weyl spinors, are investigated in detail. We formulate $ N\ge 1 $ supersymmetric self-dual Yang-Mills theories and self-dual supergravities. An N=1 ``self-dual&#39;&#39;

Sean M. Carroll, Edward Farhi, Alan H. Guth

We prove the title.

Jan Govaerts

Recent work on Euler hierarchies of field theory Lagrangians iteratively constructed {}from their successive equations of motion is briefly reviewed. On the one hand, a certain triality structure is described, relating arbitrary field theories, {\it classical\ts} topological field theories -- whose classical solutions span topological classes of manifolds --

John C. Baez

The Vassiliev-Gusarov link invariants of finite type are known to be closely related to perturbation theory for Chern-Simons theory. In order to clarify the perturbative nature of such link invariants, we introduce an algebra V_infinity containing elements g_i satisfying the usual braid group relations and elements a_i satisfying g_i - g_i^{-1} = epsilon a_i

F. Ravanini, R. Tateo, A. Valleriani

We prove a useful identity valid for all $ADE$ minimal S-matrices, that clarifies the transformation of the relative thermodynamic Bethe Ansatz (TBA) from its standard form into the universal one proposed by Al.B.Zamolodchikov. By considering the graph encoding of the system of functional equations for the exponentials of the pseudoenergies, we show that any

G. Ferretti, S. G. Rajeev

We study a three dimensional analogue of the Wess--Zumino--Witten model, which describes the Goldstone bosons of three dimensional Quantum Chromodynamics. The topologically non--trivial term of the action can also be viewed as a nonlinear realization of Chern--Simons form. We obtain the current algebra of this model by canonical methods. This is a three dime

Yigal Shamir

We discuss the quantization of theories which are formulated using compensating fields. In particular, we discuss the relation between the components formulation and the superspace formulation of supergravity theories. The requirement that the compensating field can be eliminated at the quantum level gives rise to on-shell constraints on the operators of the

R. Crittenden, Paul J. Steinhardt

Two qualitatively different modes of ending superluminal expansion are possible in extended inflation. One mode, different from the one envoked in most extended models to date, easily avoids making big bubbles that distort the cosmic microwave background radiation (CMBR). In this mode, the spectrum of density fluctuations is found to be scale-free, $P(k) \pr

R. L. Davis, H. M. Hodges, G. F. Smoot, P. J. Steinhardt

Inflation creates both scalar (density) and tensor (gravity wave) metric perturbations. We find that the tensor mode contribution to the CMB anisotropy on large-angular scales can only exceed that of the scalar mode in models where the spectrum of perturbations deviates significantly from scale invariance (e.g., extended and power-law inflation models and ex

E. S. Fradkin, V. Ya. Linetsky

A unified treatment of both superconformal and quasisuperconformal algebras with quadratic non-linearity is given. General formulas describing their structure are found by solving the Jacobi identities. A complete classification of quasisuperconformal and ${\bf Z}_2\times{\bf Z}_2$-graded algebras are obtained and in addition to the previously known cases fi

Steven B. Giddings, Andrew Strominger

Quantization of two-dimensional dilaton gravity coupled to conformal matter is investigated. Working in conformal gauge about a fixed background metric, the theory may be viewed as a sigma model whose target space is parameterized by the dilaton $ϕ$ and conformal factor $ρ$. A precise connection is given between the constraint that the theory be independent

J. F. Amundson, J. L. Rosner, M. A. Kelly, N. Horowitz

Decay constants of $D$ and $B$ mesons are estimated within the framework of a heavy-quark approach using measured isospin mass splittings in the $D$, $D^*$, and $B$ states to isolate the electromagnetic hyperfine interaction between quarks. The values $f_D = (262 \pm 29)$ MeV and $f_B = (160 \pm 17)$ MeV are obtained. Only experimental errors are given; poss

M. Jarrell, Thomas Pruschke

An essentially exact solution of the infinite dimensional Hubbard model is made possible by using a self-consistent mapping of the Hubbard model in this limit to an effective single impurity Anderson model. Solving the latter with quantum Monte Carlo procedures enables us to obtain exact results for the one and two-particle properties of the infinite dimensi

Evgeny A. Poletsky

The subject considered in this paper has, at least, three points of interest. Suppose that we have a sequence of one-dimensional analytic varieties in a domain in $\Bbb C^n$. The cluster of this sequence consists from all points in the domains such that every neighbourhood of such points intersects with infinitely many different varieties. The first question

Marco Abate, Giorgio Patrizio

In his famous 1981 paper, Lempert proved that given a point in a strongly convex domain the complex geodesics (i.e., the extremal disks) for the Kobayashi metric passing through that point provide a very useful fibration of the domain. In this paper we address the question whether, given a smooth complex Finsler metric on a complex manifold, it is possible t

S. Massar, R. Parentani, R. Brout

The particle detector model consisting of a harmonic oscillator coupled to a scalar field in $1+1$ dimensions is investigated in the inertial case. The same approach is then used in the accelerating case. The absence of radiation from a uniformly accelerated detector in a stationnary state is discussed and clarified.

A. Ch. Ganchev, V. B. Petkova

It is shown that the sl(2,C) KZ equation for (half-) integer isospins recovers, up to a gauge transformation, the matrix system for Virasoro algebra singular vectors of Bauer et al. In the case of Kac-Kazhdan spins the general (infinite matrix) KZ system is truncated due to the decoupling of the A^(1)_1 singular vectors. This suggests an algorithm converting

M. D. Freeman, K. Hornfeck, P. West

Sets of commuting charges constructed from the current of a U(1) Kac-Moody algebra are found. There exists a set S_n of such charges for each positive integer n > 1; the corresponding value of the central charge in the Feigin-Fuchs realization of the stress tensor is c = 13-6n-6/n. The charges in each series can be written in terms of the generators of an ex

M. Drees, M. M. Nojiri

We compute the cosmic relic (dark matter) density of the lightest supersymmetric particle (LSP) in the framework of minimal $N=1$ Supergravity models with radiative breaking of the electroweak gauge symmetry. To this end, we re--calculate the cross sections for all possible annihilation processes for a general, mixed neutralino state with arbitrary mass. Our

Martin J. Savage, Michael Luke, Mark B. Wise

We calculate the decay rates for $\piee$, $\etaee$ and $\etamumu$ in chiral perturbation theory. The linear combination of counterterms necessary to render these amplitudes finite is fixed by the recently measured branching fraction for $\etamumu$. We find $\Br(\piee ) = 7\pm 1\times 10^{-8}$ and $\Br(\etaee )=5\pm 1\times 10^{-9}$.

Zoltan Kunszt, Zoltán Trócsányi

A detailed investigation of the theoretical ambiguities present in the QCD description of photon production in $e^+e^-$ annihilation is given. It is pointed out that in a well-defined perturbative analysis it is necessary to subtract the quark-photon collinear singularities. This subtraction requires the introduction of an unphysical parameter in the perturb

P. L. White

In order that discrete symmetries should not be violated by gravitational effects, it is necessary to gauge them. In this paper we discuss the gauging of $\Z_N$ from the breaking of a high energy $SU(N)$ gauge symmetry, and derive consistency conditions for the resulting discrete symmetry fr om the requirement of anomaly cancellation in the parent symmetry.