October 1992 arXiv papers — page 4

T. Goldman, J. Pérez-Mercader, Fred Cooper, Michael Martin Nieto

We show how, by considering the cumulative effect of tiny quantum gravitational fluctuations over very large distances, it may be possible to: ($a$) reconcile nucleosynthesis bounds on the density parameter of the Universe with the predictions of inflationary cosmology, and ($b$) reproduce the inferred variation of the density parameter with distance. Our ca

James B. Hartle

Feynman's sum-over-histories formulation of quantum mechanics is reviewed as an independent statement of quantum theory in spacetime form. It is different from the usual Schr\"odinger-Heisenberg formulation that utilizes states on spacelike surfaces because it assigns probabilities to different sets of alternatives. Sum-over-histories quantum mechanics can b

R. Kenna, C. B. Lang

A finite-size scaling theory for the $ϕ^4_4$ model is derived using renormalization group methods. Particular attention is paid to the partition function zeroes, in terms of which all thermodynamic observables can be expressed. While the leading scaling behaviour is identical to that of mean field theory, there exist multiplicative logarithmic corrections to

Atushi Ishikawa, Haruhiko Ueda

The wave function of the universe is evaluated by using the Euclidean path integral approach. As is well known, the real Euclidean path integral diverges because the Einstein-Hilbert action is not positive definite. In order to obtain a finite wave function, we propose a new regularization method and calculate the wave function of the Friedmann- Robertson-Wa

William J. Mitchell

We use the Sigma^1_3 absoluteness theorem to show that the complexity of the statement "(omega,E)$ is isomorphic to an initial segment of the core model" is Pi^1_4, and that the complexity of the statement "(omega,E)$ is isomorphic to a member of the core model" is Delta^1_5.

Laurent Freidel, J. M. Maillet

Using a geometrical approach to the quantum Yang-Baxter equation, the quantum algebra ${\cal U}_{\hbar}(sl_{2})$ and its universal quantum $R$-matrix are explicitely constructed as functionals of the associated classical $r$-matrix. In this framework, the quantum algebra ${\cal U}_{\hbar}(sl_{2})$ is naturally imbedded in the universal envelopping algebra of

Daniel Cangemi, Roman Jackiw

In two-dimensional space-time, point particles can experience a geometric, dimension-specific gravity force, which modifies the usual geodesic equation of motion and provides a link between the cosmological constant and the vacuum $θ$-angle. The description of such forces fits naturally into a gauge theory of gravity based on the extended Poincaré group, {\i

J. R. Anglin

The influence functional is derived for a massive scalar field in the ground state, coupled to a uniformly accelerating DeWitt monopole detector in $D+1$ dimensional Minkowski space. This confirms the local nature of the Unruh effect, and provides an exact solution to the problem of the accelerating detector without invoking a non-standard quantization. A di

J. R. Anglin

The exact master equation for a harmonic oscillator coupled to a heat bath, derived recently by Hu, Paz and Zhang, is simplified by taking the weak-coupling, late-time limit. The unique time-independent solution to this simplified master equation is the canonical ensemble at the temperature of the bath. The frequency of the oscillator is effectively lowered

Joost Zegwaard

In the physical interpretation of states in non-perturbative loop quantum gravity the so-called weave states play an important role. Until now only weaves representing flat geometries have been introduced explicitly. In this paper the construction of weaves for non-flat geometries is described; in particular, weaves representing the Schwarzschild solution ar

D. V. Boulatov

The notion of $q$-deformed lattice gauge theory is introduced. If the deformation parameter is a root of unity, the weak coupling limit of a 3-$d$ partition function gives a topological invariant for a corresponding 3-manifold. It enables us to define the generalized Turaev-Viro invariant for cell complexes. It is shown that this invariant is determined by a

A. de la Macorra, G. G. Ross

We study the possibility that supersymmetry is broken via a gaugino condensate in four dimensional string theories. We derive an effective low-energy theory describing the Goldstone mode associated with the R-symmetry breaking driven by gaugino condensation and show that this gives a description of gaugino condensation equivalent, at tree level, to other eff

D. Kapetanakis, M. Mondragon, G. Zoupanos

We present phenomenologically viable $SU(5)$ unified models which are finite to all orders before the spontaneous symmetry breaking. In the case of two models with three families the top quark mass is predicted to be 178.8 GeV.

J. Tinka Gammel, John L. Gammel

We show that a highly unconventional theory, based on the 16 dimensional (${3\over2}$,${3\over2}$) irreducible representation of O(4), fits the masses of the baryons $Ξ^-$,$Ξ^0$,$Σ^-$,$Σ^0$,$Σ^+$,$Λ$,$p$,$n$ and the leptons $μ$,$e$,$ν_μ$,$ν_e$ to within current experimental error, yet yields a prediction substantially different from that of Coleman and Glash

A. S. Kronfeld, U. -J. Wiese

The dynamics of SU(N) gauge theories, especially for N=3, in a small C-periodic box are investigated. We identify the fields that mimimize the energy---the torons---and determine which of these ``classical'' vacua are stable quantum mechanically. The stable torons break cubic symmetry, which has interesting consequences on the spectrum. At any of the

B. A. Berg, T. Celik, U. Hansmann

We simulated the Edwards-Anderson Ising spin glass model in three dimensions via the recently proposed multicanonical ensemble. Physical quantities such as energy density, specific heat and entropy are evaluated at all temperatures. We studied their finite size scaling, as well as the zero temperature limit to explore the ground state properties.

M. Kapranov

We introduce a certain compactification of the space of projective configurations i.e. orbits of the group $PGL(k)$ on the space of $n$ - tuples of points in $P^{k-1}$ in general position. This compactification differs considerably from Mumford's geometric invariant theory quotient. It is obtained by considering limit position (in the Chow variety) of th

Daniel Waldram

Two string-like solutions to the equations of motion of the low-energy effective action for the heterotic string are found, each a source of electric and magnetic fields. The first carries an electric current equal to the electric charge per unit length and is the most general solution which preserves one half of the supersymmetries. The second is the most g

D. Bailin, A. Love, W. A. Sabra

The moduli dependent Yukawa couplings between twisted sectors of the $Z_3\times Z_3$ orbifold are studied.

Jeremy Schiff

The relationship between the nonlinear Schrodinger hierarchy and the parafermion and SL(2,R)/U(1) coset models, analogous to the relationship between the KdV hierarchy and the minimal models, is explained. To do this I first present an in depth study of a series of integrable hierarchies related to NLS, and write down an action from which any of these hierar

Hirosi Ooguri

We study the simplicial quantum gravity in three dimensions. Motivated by the Boulatov's model which generates a sum over simplicial complexes weighted with the Turaev-Viro invariant, we introduce boundary operators in the simplicial gravity associated to compact orientable surfaces. An amplitude of the boundary operator is given by a sum over triangulat

C. Destri, P. Maraner, E. Onofri

A selfconsistent definition of quantum free particle on a generic curved manifold emerges naturally by restricting the dynamics to submanifolds of co-dimension one. PACS 0365 0240

Jordi París

A generalization of the Faddeev-Popov procedure to deal with either anomalous and non-anomalous gauge theories with closed, irreducible gauge algebra is presented. An expression for the Wess-Zumino action is obtained.

Michael Chanowitz

Signals and backgrounds for strong $WW$ scattering at the SSC and LHC are considered. Complementarity of resonant signals in the $I=1$ $WZ$ channel and nonresonant signals in the $I=2$ \wpwp channel is illustrated using a chiral lagrangian with a $J=1$ \qrho resonance. Results are presented for purely leptonic final states in the $W^{\pm}Z$, $W^+W^+ + W^-W^-

G. Curci, G. Ricciardi

We compute the next to leading QCD corrections to weak four fermion interactions introducing a scheme that does not require an explicit definition of $γ_5$ in $d$ dimensions. This scheme reduces greatly the difficulties in calculating the two loop anomalous dimensions; we recover the results obtained in the previous literature.

F. Gliozzi

Some model-independent properties of the effective string of gauge field systems in the confining phase , for very large quark separations, are described in terms of two-dimensional conformal field theories. The constraints induced by the gauge theory at the boundaries of the effective string induce a Coulomb- like term in the interquark potential which is u

Marcus Kasner, Walter Apel

In this letter, we propose a new quasielectron trial wavefunction for $N$ interacting electrons in two dimensions moving in a strong magnetic field in a disk geometry. Requiring that the trial wavefunction exhibits the correct filling factor of a quasielectron wavefunction, we obtain $N+1$ angular momentum eigenfunctions. The expectation values of the energy

I. Dolgachev, M. Kapranov

Any arrangement of hyperplanes in general position in $P^n$ can be regarded as a divisor with normal crossing. We study the bundles of logarithmic 1-forms corresponding to such divisors` from the point of view of classification of vector bundles on $P^n$. It turns out that all such bundles are stable. The study of jumping lines of these bundles gives a unifi

A. Kuniba, T. Nakanishi

We dicuss some curious aspects of the Rogers dilogarithm and the functional relations in integrable systems in two dimensions. This is for the proceedings of the XX1 Differential Geometry Methods in Theoretical Physics, Tianjin, China, 5-9 June 1992.

Xenia C. de la Ossa, Fernando Quevedo

In string theory it is known that abelian isometries in the sigma model lead to target space duality. We generalize this duality to backgrounds with non--abelian isometries. The procedure we follow consists of gauging the isometries of the original action and constraining the field strength $F$ to vanish. This new action generates dual theories by integratin

Luis E. Ibanez

I discuss and extend several results concerning the cancellation of discrete gauge anomalies. I show how heavy fermions do not decouple in the presence of discrete gauge anomalies. As a consequence, in general, cancellation of discrete gauge anomalies cannot be described merely in terms of low energy operators involving only the light fermions. I also discus

T. Brzezinski, S. Majid

We study the quantum group gauge theory developed elsewhere in the limit when the base space (spacetime) is a classical space rather than a general quantum space. We show that this limit of the theory for gauge quantum group $U_q(g)$ is isomorphic to usual gauge theory with Lie algebra $g$. Thus a new kind of gauge theory is not obtained in this way, althoug

S. Majid

Braided tensor products have been introduced by the author as a systematic way of making two quantum-group-covariant systems interact in a covariant way, and used in the theory of braided groups. Here we study infinite braided tensor products of the quantum plane (or other constant Zamolodchikov algebra). It turns out that such a structure precisely describe

C. R. Hagen

It is shown that a recently proposed relativistic field theory of anyons is mathematically flawed and also does not satisfy reasonable criteria for such a theory.

F. Constantinescu, F. Toppan

We linearize the Artin representation of the braid group given by (right) automorphisms of a free group providing a linear faithful representation of the braid group. This result is generalized to obtain linear representations for the coloured braid groupoid and pure braid group too. Applications to some areas of two-dimensional physics are discussed.

G. Mahlon

We examine multiphoton production in the electroweak sector of the Standard Model in the high energy limit using the equivalence theorem in combination with spinor helicity techniques. We utilize currents consisting of a charged scalar, spinor, or vector line that radiates $n$ photons. Only one end of the charged line is off shell in these currents, which ar

G. Mahlon, T. M. Yan

We examine multiphoton production in the electroweak sector of the Standard Model in the high energy limit using the equivalence theorem in combination with spinor helicity techniques. We obtain recursion relations for currents consisting of a charged scalar, spinor, or vector line that radiates $n$ photons. Closed form solutions to these recursion relations

G. Mahlon, T. M. Yan, C. Dunn

We consider the process containing two quark lines and an arbitrary number of gluons in a spinor helicity framework. A current with two off-shell gluons appears in the amplitude. We first study this modified gluon current using recursion relations. The recursion relation for the modified gluon current is solved for the case of like-helicity gluons. We apply

Jooyoo Hong, Jaewan Kim, Pierre Sikivie

We derive the equations of motion for general strings, i.e. strings with arbitrary relation between tension $τ$ and energy per unit length $ε$. The renormalization of $τ$ and $ε$ that results from averaging out small scale wiggles on the string is obtained in the general case to lowest order in the amount of wiggliness. For Nambu-Goto strings we find deviati

Hai-Yang Cheng

In pure chiral perturbation theory (ChPT) the couplings of higher order Lagrangian terms are running parameters and hence can be determined only empirically from various low-energy hadronic processes. While this scenario works well for strong interactions, it is unsatisfactory for nonleptonic and radiative nonleptonic weak interactions: It is impossible, fro

R. B. Orellana, H. Vucetich

Bounds to the Nordtvedt parameter are obtained from the motion of the first twelve Trojan asteroids in the period 1906-1990. From the analysis performed, we derive a value for the inverse of the Saturn mass 3497.80 \pm 0.81 and the Nordtvedt parameter -0.56 \pm 0.48, from a simultaneous solution for all asteroids.

Ingemar Bengtsson

I review the equivalence between duality operators on two-forms and conformal structures in four dimensions, from a Clifford algebra point of view (due to Urbantke and Harnett). I also review an application, which leads to a set of "neighbours" of Einstein's equations. An attempt to formulate reality conditions for the "neighbours" is dis

C. J. Benesh

In this report, electric quadrupole corrections to the two neutron removal cross section measured in heavy ion collisions are estimated for $^{197}$Au and $^{59}$Co targets. The quadrupole process is assumed to proceed primarily through excitation of the giant isovector quadrupole resonance, which then decays by neutron emission. For $^{59}$Co, the contribut

M. Temple-Raston

We argue that there is no consistent quantisation of the two BPS SU(2) magnetic monopole dynamical system compatible with the correspondence principle.

Masayasu Harada, Koichi Yamawaki

We show that one-loop corrections with the hidden gauge boson loop preserve in the low energy limit all the successful tree level predictions of the hidden local symmetry in the SU(2)${}_L$$\times$SU(2)${}_R$$/$SU(2)${}_V$ chiral Lagrangian. Most amazingly, the $ρ$ meson dominance of the pion electromagnetic form factor survives the one-loop corrections at a

P. T. C. So, Sol M. Gruner, Shyamsunder Erramilli

Some highly unusual features of a lipid-water liquid crystal are revealed by high pressure x-ray diffraction, light scattering and dilatometric studies of the lamellar (bilayer $L_α$) to nonlamellar inverse hexagonal ($H_{II}$) phase transition. (i) The size of the unit cell of the $H_{II}$ phase increases with increasing pressure. (ii) The transition volume

Mark Bowick

I report on the observation of the production of strings (disclination lines and loops) via the Kibble mechanism of domain (bubble) formation in the isotropic to nematic phase transition of a sample of uniaxial nematic liquid crystal. The probablity of string formation per bubble is measured to be $0.33 \pm 0.01$. This is in good agreement with the theoretic

J. Horne, G. Horowitz

We investigate charged black holes coupled to a massive dilaton. It is shown that black holes which are large compared to the Compton wavelength of the dilaton resemble the Reissner-Nordström solution, while those which are smaller than this scale resemble the massless dilaton solutions. Black holes of order the Compton wavelength of the dilaton can have wor

T. Ebihara, K. -I. Kondo

For a lattice regularized chiral-invariant $SU(2)_L\times~SU(2)_R$ fermion-scalar model with a Yukawa coupling $y$ and a Wilson-Yukawa coupling $w$, we investigate the phase structure and in particular show the existence of the multicritical line, in the strong Yukawa and/or Wilson Yukawa coupling region, at which four phases meet. The result is in good agre

Kim Maltman, T. Goldman

It is shown that including form factors for the quark-pseudoscalar meson couplings of the Georgi-Manohar chiral quark model allows one to obtain the leading off-shell dependence of $π^{o}- η$ mixing (as predicted by chiral perturbation theory) from the effect of quark loops on the meson propagators. Implications for $ρ^{o} - ω$ mixing and for the effects on

Youngchul Park, Andrew Strominger

An $N = 1$ supersymmetric version of two dimensional dilaton gravity coupled to matter is considered. It is shown that the linear dilaton vacuum spontaneously breaks half the supersymmetries, leaving broken a linear combination of left and right supersymmetries which squares to time translations. Supersymmetry suggests a spinorial expression for the ADM ener

Mark J. Bowick

These are lecture notes for the 1992 Erice Workshop on String Quantum Gravity and Physics at the Planck Energy Scale. In this talk a review of earlier work on finite temperature strings was presented. Several topics were covered, including the canonical and microcanonical ensemble of strings, the behavior of strings near the Hagedorn temperature as well as s

A. S. Schwarz, A. A. Tseytlin

We observe that the ratio of determinants of $2d$ Laplacians which appear in the duality transformation relating two sigma models with abelian isometries can be represented as a torsion of an elliptic (DeRham) complex. As a result, this ratio can be computed exactly and is given by the exponential of a local functional of $2d$ metric and target space metric.

M. Talon

We study integrable dynamical systems described by a Lax pair involving a spectral parameter. By solving the classical Yang-Baxter equation when the R-matrix has two poles we show that they can be interpreted as natural motions on a twisted loop algebra.

Peter Chang, J. S. Dowker

The vacuum energy is calculated for a free, conformally-coupled scalar field on the orbifold space-time \R$\times §^2/Γ$ where $Γ$ is a finite subgroup of O(3) acting with fixed points. The energy vanishes when $Γ$ is composed of pure rotations but not otherwise. It is shown on general grounds that the same conclusion holds for all even-dimensional factored

David J. Gross

I describe our understanding of the strong interactions at the end of the 1960's and the impact of the experiments on deep inelastic scattering. I recall the steps that lead from the attempts to understand these experiments to the discovery of asymptotic freedom in 1973 and the subsequent rapid emergence, development and acceptance of the non-Abelian gau

Uwe Ritschel

Recent calculations in one-loop and Gaussian appro- ximation, using the so-called autonomous renormalization scheme, indicate a comparatively massive, narrow Higgs excitation at about 2 TeV. Here I show that this result qualitatively persists in the framework of a post-Gaussian variational approximation for the pure O(N)-symmetric phi**4-theory for N>1. The

J. Soto, R. Tzani

The question of the anomalies in the effective theory of heavy quarks is investigated at two different levels. Firstly, it is shown that none of the symmetries of this effective theory contains an anomaly. The existence of a new `$ γ_ 5 $'-symmetry is pointed out and shown to be also anomaly free. Secondly, it is shown that the chiral anomaly of QCD is n

Timothy E. Vaughan

We discuss the construction of basis states for Hamiltonian QCD on the lattice, in particular states with dynamical quark pairs. We calculate the matrix elements of the operators in the QCD Hamiltonian between these states. Along with the ``harmonic oscillator'' states introduced in previous pure SU(3) work, these states form a working basis for calc

C J Griffin, T D Kieu

Random-lattice fermions have been shown to be free of the doubling problem if there are no interactions or interactions of a non-gauge nature. On the other hand, gauge interactions impose stringent constraints as expressed by the Ward-Takahashi identities which could revive the free-field suppressed doubler modes in loop diagrams. Comparing random lattice, n

Vladimir Privman

Pairwise particle-exchange model on a linear lattice is solved exactly by a new rate-equation method. Lattice sites are occupied by particles A and B which can exchange irreversibly provided the local energy in reduced. Thus, the model corresponds to a zero-temperature Kawasaki-type phase separation process. Due to local order-parameter conservation, the dyn

Annie C. Robin, Michel Creze, Vijay Mohan

As part of a stellar population sampling program, a series of photometric probes at various field sizes and depths have been obtained in a low extinction window in the galactic anticentre direction. Such data set strong constraints on the radial structure of the disc. At the forefront of this "drilling" program, very deep CCD frames probe the most ex

E. Langmann, G. Semenoff

(a few typos and an error corrected)

Richard R. Silbar

This paper describes a user-friendly frontend to a Fortran program that integrates coupled nonlinear ordinary differential equations. The user interface is built using the NeXTstep Interface Builder, together with a public-domain graphical palette for displaying intermediate and final results. In running the code for a given set of equation parameters the us

P. Bouwknegt, K. Schoutens

We review various aspects of $\cW$-algebra symmetry in two-dimensional conformal field theory and string theory. We pay particular attention to the construction of $\cW$-algebras through the quantum Drinfeld-Sokolov reduction and through the coset construction.

Fan Wang, Guang-han Wu, Li-jian Teng, T. Goldman

We consider the effect of including quark delocalization and color screening, in the nonrelativistic quark cluster model, on baryon-baryon potentials and phase shifts. We find that the inclusion of these additional effects allows a good qualitative description of both.

Xiaolu Wang

We present the analytic foundation of a unified B-D-F extension functor $\operatorname{Ext}_τ$ on the category of noncommutative smooth algebras, for any Fréchet operator ideal $\Cal K_τ$. Combining the techniques devised by Arveson and Voiculescu, we generalize Voiculescu's theorem to smooth algebras and Fréchet operator ideals. A key notion involved is

Joel Smoller, Arthur G. Wasserman, Shing-Tung Yau, J. Bryce McLeod

We consider the Einstein/Yang-Mills equations in $3+1$ space time dimensions with $\SU(2)$ gauge group and prove rigorously the existence of a globally defined smooth static solution. We show that the associated Einstein metric is asymptotically flat and the total mass is finite. Thus, for non-abelian gauge fields the Yang/Mills repulsive force can balance t

James T. Rogers

Bounded irreducible local Siegel disks include classical Siegel disks of polynomials, bounded irreducible Siegel disks of rational and entire functions, and the examples of Herman and Moeckel. We show that there are only two possibilities for the structure of the boundary of such a disk: either the boundary admits a nice decomposition onto a circle, or it is

Curt McMullen

About a decade ago Thurston proved that a vast collection of 3-manifolds carry metrics of constant negative curvature. These manifolds are thus elements of {\em hyperbolic geometry}, as natural as Euclid's regular polyhedra. For a closed manifold, Mostow rigidity assures that a hyperbolic structure is unique when it exists, so topology and geometry mesh

Joachim Lohkamp

In this paper we announce the following result: ``Every manifold of dimension $\ge3$ admits a complete negatively Ricci curved metric.'' Furthermore we describe some sharper results and sketch proofs.

Jeffrey C. Lagarias, Peter W. Shor

O. H. Keller conjectured in 1930 that in any tiling of $\Bbb R^n$ by unit $n$-cubes there exist two of them having a complete facet in common. O. Perron proved this conjecture for $n\le 6$. We show that for all $n\ge 10$ there exists a tiling of $\Bbb R^n$ by unit $n$-cubes such that no two $n$-cubes have a complete facet in common.

Sergei V. Ivanov

It is proved that the free $m$-generated Burnside groups $\Bbb{B}(m,n)$ of exponent $n$ are infinite provided that $m>1$, $n\ge2^{48}$.

Brian R. Hunt

We present a measure-theoretic condition for a property to hold ``almost everywhere'' on an infinite-dimensional vector space, with particular emphasis on function spaces such as $C^k$ and $L^p$. Like the concept of ``Lebesgue almost every'' on finite-dimensional spaces, our notion of ``prevalence'' is translation invariant. Instead o

Hans-Jürgen Hoehnke, Kenneth W. Johnson

A set of invariants for a finite group is described. These arise naturally from Frobenius' early work on the group determinant and provide an answer to a question of Brauer. Whereas it is well known that the ordinary character table of a group does not determine the group uniquely, it is a consequence of the results presented here that a group is determi

Craig D. Hodgson, Igor Rivin, Warren D. Smith

We describe a characterization of convex polyhedra in $\h^3$ in terms of their dihedral angles, developed by Rivin. We also describe some geometric and combinatorial consequences of that theory. One of these consequences is a combinatorial characterization of convex polyhedra in $\E^3$ all of whose vertices lie on the unit sphere. That resolves a problem pos

Stuart P. Hastings, William C. Troy

We announce and outline a proof of the existence of a homoclinic orbit of the Lorenz equations. In addition, we develop a shooting technique and two key conditions, which lead to the existence of a one-to-one correspondence between a set of solutions and the set of all infinite sequences of 1's and 3's.

Karsten Grove, Steen Markvorsen

In its most general form, the recognition problem in Riemannian geometry asks for the identification of an unknown Riemannian manifold via measurements of metric invariants on the manifold. We introduce a new infinite sequence of invariants, the first term of which is the usual diameter, and illustrate the role of these global shape invariants in a number of

Fritz Gesztesy, Witold Karwowski, Zhong Xin Zhao

We announce a detailed investigation of limits of N-soliton solutions of the Korteweg-deVries (KdV) equation as $N$ tends to infinity. Our main results provide new classes of KdV-solutions including in particular new types of soliton-like (reflectionless) solutions. As a byproduct we solve an inverse spectral problem for one-dimensional Schrödinger operators

P. D. T. A. Elliott

Best possible bounds are obtained for the concentration function of an additive arithmetic function on sequences of shifted primes.

Noga Alon, Daniel J. Kleitman

A family of sets has the $(p,q)$ property if among any $p$ members of the family some $q$ have a nonempty intersection. It is shown that for every $p\ge q\ge d+1$ there is a $c=c(p,q,d)<\infty$ such that for every family $\scr F$ of compact, convex sets in $R^d$ that has the $(p,q)$ property there is a set of at most $c$ points in $R^d$ that intersects each

Peter W. Michor

We interpret the setting for a Radon transform as a submanifold of the space of generalized functions, and compute its extrinsic curvature: it is the Hessian composed with the Radon transform.

A. LeClair, C. Vafa

The quantum affine $\CU_q (\hat{sl(2)}) $ symmetry is studied when $q^2$ is an even root of unity. The structure of this algebra allows a natural generalization of N=2 supersymmetry algebra. In particular it is found that the momentum operators $P ,\bar{P}$, and thus the Hamiltonian, can be written as generalized multi-commutators, and can be viewed as new c

W. Siegel

The self-dual superstring has been described previously in a Neveu-Schwarz-Ramond formulation with local N=2 or 4 world-sheet supersymmetry. We present a Green-Schwarz-type formulation, with manifest spacetime supersymmetry.

J. Kellendonk, A. Recknagel

For any non-unitary model with central charge c(2,q) the path spaces associated to a certain fusion graph are isomorphic to the irreducible Virasoro highest weight modules.

Mirjam Cvetic

We address the possibility of false vacuum decay in $N=1$ supergravity theories, including those corresponding to superstring vacua. By establishing a Bogomol&#39;nyi bound for the energy density stored in the domain wall of the $O(4)$ invariant bubble, we show that supersymmetric vacua remain absolutely stable against false vacuum decay into another supersy

Charles Nash, Denjoe O&#39; Connor

Starting with topological field theories we investigate the Ray-Singer analytic torsion in three dimensions. For the lens Spaces L(p;q) an explicit analytic continuation of the appropriate zeta functions is contructed and implemented. Among the results obtained are closed formulae for the individual determinants involved, the large $p$ behaviour of the deter

F. A. Bais, T. Tjin, P. van Driel, J. de Boer

By generalizing the Drinfel&#39;d--Sokolov reduction we construct a large class of W algebras as reductions of Kac--Moody algebras. Furthermore we construct actions, invariant under local left and right W transformations, which are the classical covariant induced actions for W gravity. Talk presented by T. Tjin at the Trieste Summerschool on strings and rela

Guido Cognola, Luciano Vanzo

The problem of Bose-Einstein condensation for a relativistic ideal gas on a 3+1 dimensional manifold with a hyperbolic spatial part is analyzed in some detail. The critical temperature is evaluated and its dependence of curvature is pointed out.

John L. Cardy

The $Z_N$-invariant chiral Potts model is considered as a perturbation of a $Z_N$ conformal field theory. In the self-dual case the renormalization group equations become simple, and yield critical exponents and anisotropic scaling which agree with exact results for the super-integrable lattice models. Although the continuum theory is not Lorentz invariant,

Paul F. Mende

Point particles fall freely along geodesics; strings do not. In string theory all probes of spacetime structure, including photons, are extended objects and therefore always subject to tidal forces. We illustrate how string theory modifies the behavior of light in weak gravitational fields and limits the applicability of the principle of equivalence. This gi

D. V. Ahluwalia, Mikolaj Sawicki

On the one hand any effective action of the QCD, $S[π,\,ρ,\,ω,\ldots,N,\,\overline N,\,Δ^{3/2},\ldots]$, would involve, at least in principle, a tower of hadronic fields of all spins; on the other hand the front form of the field theory has emerged as an appropriate framework to investigate the high energy behaviour of many systems. Motivated by these simple

S. P. Rosen

I discuss the implications for future solar neutrino experiments of the most recent gallium data in the context of the MSW mechanism. At the low energy end of the solar neutrino spectrum we need to measure the $^7$Be component directly; and at the high energy end, we need precise measurements of the shape of the spectrum.

S. P. Rosen

I review the subject of double beta decay with emphasis upon its implications for the neutrino. It is shown that even if right-handed currents provide the phenomenological mechanism for no-neutrino decay, the fundamental mechanism underlying the process must be neutrino mass. Estimates of the mass required suggest that this mechanism is less likely than the

Mirjam Cvetic

We present a ``gravity-induced&#39;&#39; seesaw mechanism, which accommodates neutrino masses ($m_ν\propto m_u^2/M_I$, with $m_u$ the corresponding quark mass and $M_I\simeq 4\times10^{11}$ GeV) compatible with the MSW study of the Solar neutrino deficit within the minimal supersymmetric Standard Model (the grand desert with the gauge coupling unification at

G. S. Bali, K. Schilling

We present high precision results on the static quark-antiquark-potential on 32^4 and smaller lattices, using the standard Wilson action at BETA = 6.0, 6.2, 6.4, and 6.8 on the Connection Machine CM-2. Within our statistical errors (1%) we did not observe any finite size effects affecting the potential values, on varying the spatial lattice extent from 0.9 f

Bernd Bruegmann, E. Marinari

We study 4d simplicial quantum gravity in the dynamical triangulation approach with a non-trivial class of measures. We find that the measure contribution plays an important role, influencing the phase diagram and the nature of the (possible) critical theory. We discuss how the lattice theory could be used to fix the quantum measure in a non-ambiguous way.

Bernd Bruegmann

Four-dimensional euclidean quantum gravity has been studied as a discrete model based on dynamical triangulations by Ambjorn and Jurkiewicz and by Agishtein and Migdal. We discuss a particular implementation of a Monte Carlo simulation of simplicial quantum gravity. As an application we introduce a non-uniform measure and examine its effect on simple aspects

Jukka A. Ketoja

The transition from quasiperiodicity to chaos is studied in a two-dimensional dissipative map with the inverse golden mean rotation number. On the basis of a decimation scheme, it is argued that the (minimal) slope of the critical iterated circle map is proportional to the effective Jacobian determinant. Approaching the zero-Jacobian-determinant limit, the f