arXiv papers from September 1993

Frithjof Karsch

We study the scaling behaviour of the pseudo-critical couplings for the chiral phase transition in two-flavour QCD. We show that all existing results from lattice simulations on lattices with temporal extent $N_\tau = 4$, 6 and 8 can be mapped onto a universal scaling curve. The relevant combination of critical exponents, $\beta\delta$, is consistent with th

Paul S. Aspinwall, Brian R. Greene, David R. Morrison

For each family of Calabi-Yau hypersurfaces in toric varieties, Batyrev has proposed a possible mirror partner (which is also a family of Calabi-Yau hypersurfaces). We explain a natural construction of the isomorphism between certain Hodge groups of these hypersurfaces, as predicted by mirror symmetry, which we call the monomial-divisor mirror map. We indica

B. Korenblum, J. McCarthy

We prove that there is a continuous non-negative function $g$ on the unit sphere in $\cd$, $d \geq 2$, whose logarithm is integrable with respect to Lebesgue measure, and which vanishes at only one point, but such that no non-zero bounded analytic function $m$ in the unit ball, with boundary values $m^\star$, has $|m^\star| \leq g$ almost everywhere. The pro

Steven R. Bell

We show that the Bergman, Szego, and Poisson kernels associated to a finitely connected domain in the plane are all composed of finitely many easily computed functions of one variable. The new formulas give rise to new methods for computing the Bergman and Szeg\H o kernels in which all integrals used in the computations are line integrals; at no point is an

N. Seiberg

We give an intuitive proof of a new non-renormalization theorem in supersymmetric field theories. It applies both perturbatively and non-perturbatively. The superpotential is not renormalized in perturbation theory but receives non-perturbative corrections. However, these non-perturbative corrections are {\it not} generic functions of the fields consistent w

T. DeGrand

I present an overview of recent lattice QCD results on hadron spectroscopy and matrix elements. Case studies include light quark spectroscopy, the determination of $\alpha_s$ from heavy quark spectroscopy, the D-meson decay constant, a calculation of the Isgur-Wise function, and some examples of the (lack of) effect of sea quarks on matrix elements. The revi

Yi-Zhi Huang, James Lepowsky

This is the second part in a series of papers presenting a theory of tensor products for module categories for a vertex operator algebra. In Part I (hep-th/9309076), the notions of $P(z)$- and $Q(z)$-tensor product of two modules for a vertex operator algebra were introduced and under a certain hypothesis, two constructions of a $Q(z)$-tensor product were gi

J. Ignatius, K. Kajantie, H. Kurki-Suonio, M. Laine

We study how bubbles grow after the initial nucleation event in generic first-order cosmological phase transitions characterised by the values of latent heat, interface tension and correlation length, and driven by a scalar order parameter $\phi$. Equations coupling $\phi$ and the fluid variables $v$ and $T$ and depending on a dissipative constant $\Gamma$ a

G. Hastreiter, F. Forsthofer, J. Keller

We calculate frequency shifts and changes in linewidths of infrared-active phonons within a shell model for the bare phononic system coupled to an electronic double-layer structure with inter-layer charge transfer. The theoretical concept is applied to YBaCuO yielding a good description of experimental results in the normal state as well as at the transition

H. Hüffel, H. Nakazato

Quantum mechanical transition amplitudes are calculated within the stochastic quantization scheme for the free nonrelativistic particle, the harmonic oscillator and the nonrelativistic particle in a constant magnetic field; we close with free Grassmann quantum mechanics.

Thomas Buchert

The Lagrangian perturbation theory on Friedman-Lemaitre cosmologies investigated and solved up to the second order in earlier papers (Buchert 1992, Buchert \& Ehlers 1993) is evaluated up to the third order. On its basis a model for non-linear clustering applicable to the modeling of large-scale structure in the Universe for generic initial conditions is for

E. Escalera, A. Biviano, M. Girardi, G. Giuricin

The analysis of the presence of substructures in 16 well-sampled clusters of galaxies suggests a stimulating hypothesis: Clusters could be classified as unimodal or bimodal, on the basis of to the sub-clump distribution in the {\em 3-D} space of positions and velocities. The dynamic study of these clusters shows that their fundamental characteristics, in par

Sandra Savaglio, Sandro D'Odorico, Palle Møller

We have obtained high, 11 and 14 \kms, and medium, 40 and 53 \kms, resolution spectra of the $z_{em} = 4.11$ quasar Q0000--2619 covering the range 4400 \AA\ to 9265 \AA . We identify nine metal absorption systems, of which four were previously known. A fifth previously suggested system at $z_{abs} \approx 3.409$ (Turnshek et al~ 1991) is ruled out by our dat

Hitoshi Kitada

A model of a stationary universe is proposed. In this framework, time is defined as a local and quantum-mechanical notion in the sense that it is defined for each local and quantum-mechanical system consisting of finite number of particles. The total universe consisting of infinite number of particles has no time associated. It is a stationary bound state of

T. Morii, S. Tanaka, T. Yamanishi

The recent SMC data of $xg_1^d(x)$ are reproduced with the large polarized gluons. To study further the polarized gluon distribution in a proton, we calculate the spin--dependent differential cross section for J/$\psi$ leptoproductions and the two--spin asymmetry for J/$\psi$ hadroproductions. Its experimental implication is discussed.

Ulf H. Danielsson

The $1/x^{2}$ deformed $c=1$ matrix model is studied at finite radius and non-zero cosmological constant. Calculational techniques are presented and illustrated in some examples. Furthermore, a new kind of $R \rightarrow 1/R$ duality is discovered which mixes different genus.

Karl Mannheim

Nuclear jets containing relativistic ``hot'' particles close to the central engine cool dramatically by producing high energy radiation. The radiative dissipation is similar to the famous Compton drag acting upon ``cold'' thermal particles in a relativistic bulk flow. Highly relativistic protons induce anisotropic showers raining electromagne

T. Buchert, A. L. Melott, A. G. Weiss

We present results showing an improvement of the accuracy of perturbation theory as applied to cosmological structure formation for a useful range of quasilinear scales. The Lagrangian theory of gravitational instability of an Einstein-de Sitter dust cosmogony investigated and solved up to the third order in the series of papers by Buchert (1989, 1992, 1993a

C. Alcock, C. W. Akerlof, R. A. Allsman, T. S. Axelrod

There is now abundant evidence for the presence of large quantities of unseen matter surrounding normal galaxies, including our own$^{1,2}$. The nature of this `dark matter' is unknown, except that it cannot be made of normal stars, dust, or gas, as they would be easily detected. Exotic particles such as axions, massive neutrinos or other weakly interacting

L. Xiong, E. Shuryak

Hot gluons are the dominant components of the QCD plasma to be formed in future high energy heavy ion experiments. In this paper we study the elementary processes in the plasma medium for gluon multiplication based on all orders of the tree-diagrams in perturbative QCD. When applying to the chemical equilibration in the expanding system, we found that the gl

A. Candiello, K. Lechner

We present a unified treatment in superspace of the two dual formulations of $D=10$, $N=1$ {\it pure} supergravity based on a strictly super-geometrical framework: the only fundamental objects are the super Riemann curvature and torsion, and the related Bianchi identities are sufficient to set the theory on shell; there is no need to introduce, from the begi

F. Belgiorno, A. S. Cattaneo

(some corrections in the semiclassical study and one reference added).

Christopher A. Metzler, August E. Evrard

The formation and evolution of an X--ray cluster is studied using a 3--D N-body + hydrodynamical simulation which includes feedback of energy and iron from cluster galaxies. The differences in evolution and final state between the simulation and a similar run without feedback are highlighted. We address the energetics of cluster gas; the distribution of dark

R. Casalbuoni, P. Chiappetta, A. Deandrea, S. De Curtis

We consider the possibility of detecting vector resonances from a strong electroweak sector, in the framework of the BESS model, at future $e^+ e^-$ colliders up to the TeV range. If the mass $M_V$ of the new vector boson multiplet is not far above or if it is below the maximum machine energy, such a contribution would be manifest. The process of $W$-pair pr

D. T. Son, P. G. Tinyakov

Two-parameter sets of solutions to the classical field equations in the massless $\phi^4$ model and SU(2) gauge theory are found, each solution presumably describing a multi-particle instanton-like transition at high energy. In the limit of small number of initial particles, the probability of the transition is suppressed by $\exp(-2S_0)$, where $S_0$ is the

Stefan Gottloeber, Jan P. Muecket, A. Starobinsky

CDM models with non-scale-free step-like spectra of adiabatic perturbations produced in a realistic double inflationary model are compared with recent observational data. The model contains two additional free parameters relatively to the standard CDM model with the flat ($n=1$) initial spectrum. Results of the COBE experiment are used for the determination

S. Mollerach, S. Matarrese, F. Lucchin

We investigate inflationary models leading to density perturbations with a spectral index $n>1$ (``blue spectra"). These perturbation spectra may be useful to simultaneously account for both the amount of ultra large-scale power required to fit cosmic microwave background anisotropies, such as those measured by COBE, and that required to give bulk motions an

Raj Gandhi, Jorge L. Lopez, D. V. Nanopoulos, Kajia Yuan

Galactic halo neutralinos ($\chi$) captured by the Sun or Earth produce high-energy neutrinos as end-products of various annihilation modes. These neutrinos can travel from the Sun or Earth cores to the neighborhood of underground detectors (``neutrino telescopes") where they can interact and produce upwardly-moving muons. We compute these muon fluxes in the

A. M. Tsvelik

The model of Kondo chain with $M$-fold degenerate band of conduction electrons of spin 1/2 interacting with localized spins $S$ is studied for the case when the electronic band is half filled. It is shown that the spectrum of spin excitations in the continuous limit is described by the O(3) nonlinear sigma model with the topological term with $\theta = \pi(2

I. Pagonabarraga, M. Rubi

We study the dynamics of density fluctuations in purely diffusive systems away from equilibrium. Under some conditions the static density correlation function becomes long-ranged. We then analyze this behavior in the framework of nonequilibrium fluctuating hydrodynamics.

Yoshiaki SOFUE

We simulated the behavior of interstellar gas clouds in a companion galaxy during a gas-dynamical interaction with the halo and disk of a spiral galaxy. By ram pressure, the gas clouds are stripped from the companion, and accreted to ward the disk of the spiral galaxy. If the companion's orbit is retrograde with respect to the rotation of the spiral galaxy,

R. Chitra, Sumathi Rao, Diptiman Sen

We use a recently developed bosonic mean-field theory (MFT) to study the ordered ground states of frustrated Heisenberg antiferromagnets (FHAFM) in two dimensions. We emphasize the role of condensates in satisfying the MF variational equations and their relation to spin correlation functions at low temperatures. Our results are similar to those obtained usin

Y. Sofue, S. Yoshida, T. Aoki, T. Soyano

By image processing and color excess analyses of B, V, R, and I-band CCD images of the central region of M31 taken with the Kiso 105-cm Schmidt telescope, we found a bar of 200 pc length. We also found a more extended ``face-on" spiral feature of dark clouds, which appear t o be connected to this bar and is probably an out-of-plane structure. The \co-lin

Yoshiaki SOFUE

Radio continuum observations of the galactic center region have revealed a number of vertical structures running across the galactic plane. Most of the vertical structures are reasonably attributed either to poloidal magnetic field or to energy release toward the halo. The relation of the continuum structures to the molecular gas rings and their vertical ext

Peter Möller, J. Rayford Nix

We present some new results on heavy-element nuclear-structure properties calculated on the basis of the finite-range droplet model and folded-Yukawa single-particle potential. Specifically, we discuss calculations of nuclear ground-state masses and microscopic corrections, $\alpha$-decay properties, $\beta$-decay properties, fission potential-energy surface

A. P. Balachandran, L. Chandar, E. Ercolessi, T. R. Govindarajan

The Maxwell-Chern-Simons (MCS) Lagrangian is the Maxwell Lagrangian augmented by the Chern-Simons (CS) term. In this paper, we study the MCS and Maxwell Lagrangians on a disk $D$. They are of interest for the quantum Hall effect, and also when the disk and its exterior are composed of different media. We show that quantization is not unique, but depends on a

Dimitra Karabali

Some algebraic issues of the FQHE are presented. First, it is shown that on the space of Laughlin wavefunctions describing the $\nu =1/m$ FQHE, there is an underlying $W_{\infty}$ algebra, which plays the role of a spectrum generating algebra and expresses the symmetry of the ground state. Its generators are expressed in a second quantized language in terms

Martin Luescher

The theory underlying a proposed random number generator for numerical simulations in elementary particle physics and statistical mechanics is discussed. The generator is based on an algorithm introduced by Marsaglia and Zaman, with an important added feature leading to demonstrably good statistical properties. It can be implemented exactly on any computer c

S. Tremaine. D. O. Richstone, Y. -I. Byun, A. Dressler, S. M. Faber

We describe a one-parameter family of models of stable spherical stellar systems in which the phase-space distribution function depends only on energy. The models have similar density profiles in their outer parts ($\rho\propto r^{-4}$) and central power-law density cusps, $\rho\propto r^{3-\eta}$, $0<\eta\le 3$. The family contains the Jaffe (1983) and Hern

D. J. Dean, S. E. Koonin, G. H. Lang, P. B. Radha

We present the first auxiliary field Monte Carlo calculations for a rare earth nucleus, Dy-170. A pairing plus quadrupole Hamiltonian is used to demonstrate the physical properties that can be studied in this region. We calculate various static observables for both uncranked and cranked systems and show how the shape distribution evolves with temperature. We

M. C. Nemes, Saulo C. S. Silva

In the present contribution we show that the introduction of axial currents in electrodynamics can explain the quantization of electric charge and introduces a dynamical discreteness of space-time, justifying thus the regularization of Feymman's integrals.

Martin Holthaus, Daniel W. Hone

The ac Stark effect can shift initially nonresonant minibands in semiconductor superlattices into multiphoton resonances. This effect can result in strongly enhanced generation of a particular desired harmonic of the driving laser frequency, at isolated values of the amplitude.

Zhong-Shui Ma, Yi-Xin Chen, Zhao-Bin Su

The conductance sum rule for the hierarchical edge channel currents of a Fractional Quantum Hall Effect state is derived analytically within the Haldane-Halperin hierarchy scheme. We provide also an intuitive interpretation for the hierarchical drift velocities of the edge excitations.

Olivier Babelon, Denis Bernard

We consider the N-soliton solutions in the sine-Gordon model as a N-body problem. This leads to a relativistic generalization of the Calogero model first introduced by Ruijsenaars. We show that the fundamental Poisson bracket of the Lax matrix is quadratic, and the $r$-matrix is a dynamical one. This is in contrast to the Calogero model where the fundamental

J. C. Ciria, A. Tarancon

We compute, on the $(\lambda \Phi^4)_{1+1}$ model on the lattice, the soliton mass by means of two very different numerical methods. First, we make use of a ``creation operator'' formalism, measuring the decay of a certain correlation function. On the other hand we measure the shift of the vacuum energy between the symmetric and the antiperiodic systems. The

A. Ballestrero, E. Maina, S. Moretti, C. Pistarino

We study the cross sections for the production of a neutral, intermediate mass Higgs boson in the processes $pp\rightarrow tq'\Phi$, $pp\rightarrow tW^-\Phi$ and $pp\rightarrow bZ^0\Phi$ in the Minimal Supersymmetric Standard Model ($\Phi=H^0,h^0$ and $A^0$) at Supercollider energies. The additional heavy particles ($t$, $W$, $Z$) in the final state can be u

R. Fritz, H. Müther

Two different approximation schemes for the self-consistent solution of the relativistic Brueckner-Hartree-Fock equation for finite nuclei are discussed using realistic One-Boson-Exchange potentials. In a first scheme, the effects of correlations are deduced from a study of nuclear matter and parameterized in terms of an effective $\sigma$, $\omega$ and $\pi

P. Bowcock, G. M. T. Watts

We consider 3-point and 4-point correlation functions in a conformal field theory with a W-algebra symmetry. Whereas in a theory with only Virasoro symmetry the three point functions of descendants fields are uniquely determined by the three point function of the corresponding primary fields this is not the case for a theory with $W_3$ algebra symmetry. The

Alberto Saa

The role of space-time torsion in general relativity is reviewed in accordance with some recent results on the subject. It is shown that, according to the connection compatibility condition, the usual Riemannian volume element is not appropriate in the presence of torsion. A new volume element is proposed and used in the Lagrangian formulation for Einstein-C

Yoshio Koide

A phenomenological quark mass matrix model which includes only two adjustable parameters is proposed from the point of view of the unification of quark and lepton mass matrices. The model can provide reasonable values of quark mass ratios and Kobayashi-Maskawa matrix parameters.

J. R. Bond, Robert Crittenden, Richard L. Davis, George Efstathiou

The cosmic microwave background anisotropy is sensitive to the slope and amplitude of primordial energy density and gravitational wave fluctuations, the baryon density, the Hubble constant, the cosmological constant, the ionization history, {\it etc.} In this Letter, we examine the degree to which these factors can be separately resolved from combined small-

M. Novotny, H. G. Evertz

We report current progress on the synthesis of methods to alleviate two major difficulties in implementing a Monte Carlo Renormalization Group (MCRG) for quantum systems. In particular, we have utilized the loop-algorithm to reduce critical slowing down, and we have implemented an MCRG method in which the symmetries of the classical equivalent model need not

Junwu Gan

The free energy and magnetization for the general $SU(N)$ one impurity Kondo model in the magnetic field, $h$, are calculated by extending the previous $1/N$ expansion technique: the saddle point is determined self-consistently to the $1/N$ order. The obtained universal field dependent magnetization $M(h/T_{K})$ by this simple method is shown analytically to

Junwu Gan

A detailed and comprehensive study of the one-impurity multichannel Kondo model is presented. In the limit of a large number of conduction electron channels $k \gg 1$, the low energy fixed point is accessible to a renormalization group improved perturbative expansion in $1/k$. This straightforward approach enables us to examine the scaling, thermodynamics an

Junwu Gan, Eugene Wong

The problem of an electron gas interacting via exchanging transverse gauge bosons is studied using the renormalization group method. The long wavelength behavior of the gauge field is shown to be in the Gaussian universality class with a dynamical exponent $z=3$ in dimensions $D \geq 2$. This implies that the gauge coupling constant is exactly marginal. Scat

K. -I. Izawa

We consider a new perturbation scheme in nonabelian gauge theory. Pure Yang-Mills theory in three dimensions is taken as a concrete example. The zeroth-order in the perturbative expansion is given by BF theory coupled to a St{\" u}ckelberg-like field. The effective coupling for the expansion can be small in the infrared regime, which implies that nonperturba

Tom H. Koornwinder

Extended abstract for the Proceedings of the Conference ``Modern developments in complex analysis and related topics'' (on the occasion of the 70th birthday of prof.\ dr.\ J. Korevaar), University of Amsterdam, January 27--29, 1993.

Andrei Linde

In this talk we discuss three different issues. First of all, there exist several proposals how to solve cosmological problems by adiabatic expansion of the Universe, without any use of inflation. We explain why these models do not solve the flatness/entropy problem. On the other hand there exist some claims that inflation also does not solve the flatness pr

E. T. Vishniac

I review recent work on the radial transport of angular momentum in ionized, Keplerian accretion disks. Proposed mechanisms include hydrodynamic and MHD local instabilities and long range effects mediated by wave transport. The most promising models incorporate the Velikhov-Chandrasekhar instability, caused by an instability of the magnetic field embedded in

Ned S. Wingreen, Yigal Meir

The infinite-U Anderson model is applied to transport through a quantum dot. The current and density of states are obtained via the non-crossing approximation for two spin-degenerate levels weakly coupled to two leads. At low temperatures, the Kondo peak in the equilibrium density of states strongly enhances the linear-response conductance. Application of a

S. B. Giddings, J. A. Harvey, Joseph Polchinski, S. H. Shenker

Solutions of bosonic string theory are constructed which correspond to four-dimensional black holes with axionic quantum hair. The basic building blocks are the renormalization group flows of the CP1 model with a theta term and the SU(1,1)/U(1) WZW coset conformal field theory. However the solutions are also found to have negative energy excitations, and are

C. Aragone, Pio J. Arias, A. Khoudeir

It is shown that topological massive gravity augmented by the triadic gravitational Chern-Simons first order term is a curved a pure spin-2 action. This model contains two massive spin-2 excitations. However, since its light-front energy is not semidefinite positive, this double CS-action does not have any physical relevance.In other words, topological massi

A. A. Bel'kov, G. Bohm, A. V. Lanyov, A. Schaale

The calculations of isotopic amplitudes and their results for the direct $CP$--violating charge asymmetry in $K^\pm \to 3\pi$ decays within the nonlinear and linear ($\sigma$--model) chiral Lagrangian approach are compared with each other. It is shown, that the latter, taking into account intermediate scalar resonances, does not reproduce the $p^4$--correcti

Mikhail S. Plyushchay

With the help of the deformed Heisenberg algebra involving Klein operator, we construct the minimal set of linear differential equations for the (2+1)-dimensional relativistic field with arbitrary fractional spin, whose value is defined by the deformation parameter.

Mikhail S. Plyushchay

The identity of classical motion is established for two physically different models, one of which is the relativistic particle with torsion, whose action contains higher derivatives and which is the effective system for the statistically charged particle interacting with the Chern-Simons U(1) gauge field, and another is the (2+1)-dimensional relativistic cha

Leonard Susskind

The classical Bekenstein entropy of a black hole is argued to arise from configurations of strings with ends which are frozen on the horizon. Quantum corrections to this entropy are probably finite unlike the case in quantum field theory. Finally it is speculated that all black holes are single string states. The level density of strings is of the right orde

P. G. O. Freund, A. V. Zabrodin

The spectral problem for the q-Knizhnik-Zamolodchikov equations for $U_{q}(\widehat{sl_2}) (0<q<1)$ at arbitrary level $k$ is considered. The case of two-point functions in the fundamental representation is studied in detail.The scattering states are given explicitly in terms of continuous q-Jacobi polynomials, and the $S$-matrix is derived from their asympt

Valeri V. Dvoeglazov, Rudolf N. Faustov, Yuri N. Tyukhtyaev

The present review includes the description of theoretical methods for the investigations of the spectra of hydrogen-like systems. Various versions of the quasipotential approach and the method of the effective Dirac equation are considered. The new methods, which have been developed in the eighties, are described. These are the method for the investigation

J. Milana

A higher--twist nuclear enhancement of $R = \sigma_L/\sigma_T$, as might be expected to arise due to fermi motion and whose magnitude is within the error-bars of recent experiment, is shown to lead to a monotonic {\it decrease} in the ratio of nuclear vs. nucleon cross--sections at small Bjorken $x$ for {\it increasing} $Q^2$. This effect at small $x$, compa

Gregory Pelts

A self-consistent string field theory with interaction is formulated. The symmetry algebra of this theory includes, in the low-energy limit, local space-time symmetries, and the Brans-Dicke equation describes a class of low-energy solutions. (Talk given at the conference Journees Relativistes'93 held on April 5-7 1993, To be published in the International Jo

T. Kolatt, A. Dekel

We test the hypothesis that the velocity field derived from Tully-Fisher measurements of spiral galaxies, and that derived independently from Dn-sigma measurements of ellipticals and S0s, are noisy versions of the same underlying velocity field. The radial velocity fields are derived using tensor Gaussian smoothing of radius 1200 km/s. They are compared at g

Istvan Montvay

After discussing the problem of lattice regularization of chiral gauge theories, a simple model for anomalous fermion number violation is formulated which can be numerically studied with present day technique. Exploratory results of numerical simulations of a two-dimensional U(1) Higgs model are presented.

P. Gambino, A. Sirlin

The relation between $\sef$, frequently employed in LEP analyses, and the $\rm{\overline{MS}}$--parameter $\scr$ is discussed and their difference evaluated by means of an explicit calculation.

M. Bershadsky, S. Cecotti, H. Ooguri, C. Vafa

We develop techniques to compute higher loop string amplitudes for twisted $N=2$ theories with $\hat c=3$ (i.e. the critical case). An important ingredient is the discovery of an anomaly at every genus in decoupling of BRST trivial states, captured to all orders by a master anomaly equation. In a particular realization of the $N=2$ theories, the resulting st

Oscar Diego, Jose Gonzalez

We remark that the weak coupling regime of the stochastic stabilization of 2D quantum gravity has a unique perturbative vacuum, which does not support instanton configurations. By means of Monte Carlo simulations we show that the nonperturbative vacuum is also confined in one potential well. Nonperturbative effects can be assessed in the loop equation. This

Robert Braun, Kristian Ranestad

P. Ellia and G.Sacchiero have shown that if $S$ is a smooth surface in $\Pn 4$ which is ruled in conics, then $S$ has degree 4 or 5. In this paper we give a proof of this result combining the ideas of Ellia and Sacchiero as they are used in the paper of the second author on plane curve fibrations and the recent work of G. Fl\o ystad and the first author boun

T. Fukui, N. Aizawa

An algebraic treatment of shape-invariant potentials in supersymmetric quantum mechanics is discussed. By introducing an operator which reparametrizes wave functions, the shape-invariance condition can be related to a oscillator-like algebra. It makes possible to define a coherent state associated with the shape-invariant potentials. For a large class of suc

M. Chaichian, R. Gonzalez Felipe, D. Louis Martinez

We propose a simple model for a free relativistic particle of fractional spin in 2+1 dimensions which satisfies all the necessary conditions. The canonical quantization of the system leads to the description of one- particle states of the Poincare group with arbitrary spin. Using the Hamil- tonian formulation with the set of constraints, we introduce the ele

Yong-Cong Chen, Kai Xiu

The Gutzwiller projection of the Schwinger-boson mean-field solution of the 2-d spin-1/2 antiferromagnet in a square lattice is shown to produce the optimized, parameter-free RVB ground state. We get $-0.6688J$/site and $0.311$ for the energy and the staggered magnetization. The spectrum of the excited states is found to be linear and gapless near $\bk\cong

M. Hotta, M. Yoshimura

Quantum back reaction due to $N$ massless fields may be worked out to a considerable detail in a variant of integrable dilaton gravity model in two dimensions. It is shown that there exists a critical mass of collapsing object of order $\hbar N \times$ (cosmological constant)$^{1/2}$, above which the end point of Hawking evaporation is two disconnected remna

Bhuvnesh Jain, Edmund Bertschinger

The cosmological fluid equations are used to study the nonlinear mode coupling of density fluctuations. We find that for realistic cosmological spectra there is a significant contribution to the nonlinear evolution on scales of interest to large-scale structure from the long-wave part of the initial spectrum. A consequence of this mode coupling is that at hi

F. Lucchin, S. Matarrese, L. Moscardini, G. Tormen

We study the cosmic peculiar velocity field as traced by a sample of 1184 spiral, elliptical and S0 galaxies, grouped in 704 objects. We carry out a statistical analysis, by calculating bulk flows and velocity correlation functions for this sample and for mock catalogs which we extract from N--body simulations. For the simulations we consider tilted (i.e. wi

Claude Bernard, Thomas A. DeGrand, Carleton DeTar, Steven Gottlieb

As part of an ongoing effort to characterize the high temperature phase of QCD, in a numerical simulation using the staggered fermion scheme, we measure the quark baryon density in the vicinity of a fixed test quark at high temperature and compare it with similar measurements at low temperature and at the crossover temperature. We find an extremely weak corr

Karen M. Strom, Stephen E. Strom

We have carried out a deep (t=30000s) x-ray search of the eastern portion of the L1495 cloud centered on the well known weak line T Tauri star (WTTS) V410 Tau using the ROSAT PSPC. This deep exposure enabled a search for candidate pre-main sequence (PMS) objects in this cloud to a limit 20 times more sensitive than that typical of the fields examined with th

A. Kuniba, T. Nakanishi, J. Suzuki

We study a system of functional relations among a commuting family of row-to-row transfer matrices in solvable lattice models. The role of exact sequences of the finite dimensional quantum group modules is clarified. We find a curious phenomenon that the solutions of those functional relations also solve the so-called thermodynamic Bethe ansatz equations in

Yosef Nir

We review new physics effects on CP violation in B decays. We describe the Standard Model predictions for the various types of CP asymmetries and discuss the theoretical cleanliness of these predictions. We point out the ingredients in the analysis that are most sensitive to new physics and deduce the type of new physics that is likely to modify the Standard

J. Layssac, F. M. Renard, G. Gounaris

We study vector boson pair production at $LHC$ and $SSC$, taking into account the effects generated by the anomalous vector boson and Higgs couplings induced by the operators ${\cal O}_W$ and ${\cal O}_{UW}$, which are the only dim=6 operators preserving $SU(2)_c$. These operators lead to enhanced production of transverse vector bosons, as opposed to the enh

M. Fukugita, M. Kawasaki

We investigate reheating of the universe by early formation of stars and quasars in the hierarchical clustering scheme of cold dark matter scenario, with perturbation fluctuations normalized by the COBE data. It is found that ionizing uv flux from OB stars with the abundance given by the standard initial mass function is strong enough to ionize the universe

Máximo Bañados, Claudio Teitelboim, Jorge Zanelli

The Euclidean black hole has topology $\Re^2 \times {\cal S}^{d-2}$. It is shown that -in Einstein's theory- the deficit angle of a cusp at any point in $\Re^2$ and the area of the ${\cal S}^{d-2}$ are canonical conjugates. The black hole entropy emerges as the Euler class of a small disk centered at the horizon multiplied by the area of the ${\cal S}^{d-2}$

F. Coester, D. O. Riska

The effective electromagnetic current density for a two-nucleon system that is described by the Blankenbecler-Sugar equation is derived. In addition to the single nucleon currents there are exchange currents of two different origins. The first is the exchange current that is required to compensate for the violation of the continuity equation in the impulse a

Dierk Bormann, Hans Beck

We study the two-dimensional Ginzburg-Landau model of a neutral superfluid in the vicinity of the vortex unbinding transition. The model is mapped onto an effective interacting vortex gas by a systematic perturbative elimination of all fluctuating degrees of freedom (amplitude {\em and} phase of the order parameter field) except the vortex positions. In the

R. R. Caldwell

A method for calculating the retarded Green's function for the gravitational wave equation in Friedmann-Roberson-Walker spacetimes, within the formalism of linearized Einstein gravity is developed. Hadamard's general solution to Cauchy's problem for second-order, linear partial differential equations is applied to the FRW gravitational wave equation. The ret

Daniel Armand-Ugon, Rodolfo Gambini, Pablo Mora

An extension of the Artin Braid Group with new operators that generate double and triple intersections is considered. The extended Alexander theorem, relating intersecting closed braids and intersecting knots is proved for double and triple intersections, and a counter example is given for the case of quadruple intersections. Intersecting knot invariants are

N. Yu Reshetikhin, H. Saleur

We show that integrable vertex and RSOS models with trigonometric Boltzmann weights and appropriate inhomogeneities provide a convenient lattice regularization for massive field theories and for the recently studied massless field theories that interpolate between two non trivial conformal field theories. Massive and massless S matrices are computed from the

Bernard PICHON CNRS

We present some results and remarks based on a combinatorial approach of the evaluation of the nuclear level density. First, we show that it is possible to extract some reliable information from the output of the program whose rough data present a strong statistical fluctuation from bin to bin. This includes smoothing and evaluation of the desired quantities

F. D. M. Haldane, M. R. Zirnbauer

We calculate the exact dynamical magnetic structure factor S(Q,E) in the ground state of a one-dimensional S=1/2 antiferromagnet with gapless free S=1/2 spinon excitations, the Haldane-Shastry model with inverse-square exchange, which is in the same low-energy universality class as Bethe's nearest-neighbor exchange model. Only two-spinon excited states contr

A. A. Anselm, Myron Bander

High energy reactions may produce a state around the collision point that is best described by a classical pion field. Such a field might be an isospin rotated vacuum of the chiral $\sigma$-model or, as discussed in this work, a solution of the equations of motion resultinng from the coupling of fields of this model to quarks produced in the collision. In su

Martin Bordemann, Eckhard Meinrenken, Martin Schlichenmaier

For general compact K\"ahler manifolds it is shown that both Toeplitz quantization and geometric quantization lead to a well-defined (by operator norm estimates) classical limit. This generalizes earlier results of the authors and Klimek and Lesniewski obtained for the torus and higher genus Riemann surfaces, respectively. We thereby arrive at an approximati

C. Aragone, P. J. Arias, A. Khoudeir

We present a second order gravity action which consists of ordinary Einstein action augmented by a first-order, vector like, Chern-Simons quasi topological term. This theory is ghost-free and propagates a pure spin-2 mode. It is diffeomorphism invariant, although its local Lorentz invariance has been spontaneuosly broken. We perform the light-front (LF) anal

C. Aragone P. J. Arias

The anyonic behaviour of massive spinning point particles coupled to linearized massive vector Chern-Simons gravity is studied. This model constitutes the uniform spin-2 generalization of the vector model formed by coupling charged point particles to the topological massive Maxwell-CS action. It turns out that, for this model, the linearized first order tria