May 1995 arXiv papers — page 6

Pei-Ming Ho

An algebraic formulation of Riemannian geometry on quantum spaces is presented, where Riemannian metric, distance, Laplacian, connection, and curvature have their counterparts. This description is also extended to complex manifolds. Examples include the quantum sphere, the complex quantum projective spaces and the two-sheeted space.

R. M. Avakian, G. Oganessyan

We analyse the expression for the mass of a stationary axisymmetric configuration in general relativity obtained in our previous work [1]. From the generality of our formula and its incompatibility with the corresponding expression in Kerr space-time we argue that a stationary equilibrium distribution of a real matter cannot be a source of the Kerr metric.

Lee Smolin

Quantum gravity is studied nonperturbatively in the case in which space has a boundary with finite area. A natural set of boundary conditions is studied in the Euclidean signature theory, in which the pullback of the curvature to the boundary is self-dual (with a cosmological constant). A Hilbert space which describes all the information accessible by measur

Emili Elizalde, Sergei D. Odintsov, August Romeo

The O(N) non-linear sigma model in a $D$-dimensional space of the form ${\bf R}^{D-M} \times {\bf T}^M$, ${\bf R}^{D-M} \times {\bf S}^M$, or ${\bf T}^M \times {\bf S}^P$ is studied, where ${\bf R}^M$, ${\bf T}^M$ and ${\bf S}^M$ correspond to flat space, a torus and a sphere, respectively. Using zeta regularization and the $1/N$ expansion, the corresponding

Yi-Zhi Huang, James Lepowsky

This is the third part in a series of papers developing a tensor product theory for modules for a vertex operator algebra. The goal of this theory is to construct a ``vertex tensor category'' structure on the category of modules for a suitable vertex operator algebra. The notion of vertex tensor category is essentially a ``complex analogue'' of the notion of

Kai-Ming Lee, Hoi-Kwong Lo

We construct exact wavefunctions of two vortices on a plane, a single vortex on the cylinder and a vortex on the torus. In each case, the physics is shown to be equivalent to a particle moving in a covering space, something simple to solve in those examples. We describe how our solutions fit into the general theory of quantum mechanics of $N$ particles on a

M. Praszalowicz, A. Blotz, K. Goeke

We calculate $g_A^3$ and $g_A^0$ in the Chiral Quark-Soliton Model (or equivalently in semibosonized Nambu--Jona-Lasinio model) in the limit of small and large soliton size. In small soliton limit we recover the results of the Constituent Quark Model. The agreement between the two models is achieved due to the recently calculated $1/\Nc$ contributions to $g_

Shamit Kachru, Cumrun Vafa

We search for $N=2$, $d=4$ theories which can be realized both as heterotic string compactifications on $K_{3}\times T^{2}$ and as type II string compactifications on Calabi-Yau threefolds. In such cases, the exact non-perturbative superpotential of one string theory is given in terms of tree level computations in the other string theory. In particular we fi

James V. Steele, Hidenaga Yamagishi, Ismail Zahed

The master formula approach to chiral symmetry breaking is used to analyze the phase shifts for $ππ$ scattering in the elastic region. The results are in excellent agreement with the data for the phase shifts up to the K-K bar threshold. Our analysis shows that the pi-pi data near threshold in the scalar channel favors a large quark condensate in the vacuum,

F. Gliozzi, R. Tateo

In the Thermodynamic Bethe Ansatz approach to 2D integrable, ADE-related quantum field theories one derives a set of algebraic functional equations (a Y-system) which play a prominent role. This set of equations is mapped into the problem of finding finite triangulations of certain 3D manifolds. This mapping allows us to find a general explanation of the per

S. F. King, P. L. White

We perform a detailed analysis of the next-to-minimal supersymmetric standard model (NMSSM), imposing the constraints of two-loop gauge coupling unification, universal soft supersymmetry breaking and the correct pattern of electroweak symmetry breaking. We compare our results with those for the minimal supersymmetric standard model (MSSM) using closely relat

G. Raimann, A. Ozawa, R. N. Boyd, F. R. Chloupek

The $β$-delayed neutron decay of $^{17}$B was studied using a radioactive ion beam. The neutron energies, measured via time-of-flight, give information on states in $^{17}$C above the $^{16}$C + neutron threshold. States in $^{17}$C were found at excitation energies of 2.25(2) MeV, 2.64(2) MeV and 3.82(5) MeV, and possibly at 1.18(1) MeV. These low lying sta

V. E. Adler, I. T. Habibullin

The problem of construction of the boundary conditions for the Toda lattice compatible with its higher symmetries is considered. It is demonstrated that this problem is reduced to finding of the differential constraints consistent with the ZS-AKNS hierarchy. A method of their construction is offered based on the Bäcklund transformations. It is shown that the

Robert B. Griffiths

Precise rules are developed in order to formalize the reasoning processes involved in standard non-relativistic quantum mechanics, with the help of analogies from classical physics. A classical or quantum description of a mechanical system involves a {\it framework}, often chosen implicitly, and a {\it statement} or assertion about the system which is either

Yi-Zhi Huang

In the references [HL1]--[HL5] and [H1], a theory of tensor products of modules for a vertex operator algebra is being developed. To use this theory, one first has to verify that the vertex operator algebra satisfies certain conditions. We show in the present paper that for any vertex operator algebra containing a vertex operator subalgebra isomorphic to a t

Yi-Zhi Huang

This is the fourth part of a series of papers developing a tensor product theory of modules for a vertex operator algebra. In this paper, We establish the associativity of $P(z)$-tensor products for nonzero complex numbers $z$ constructed in Part III of the present series under suitable conditions. The associativity isomorphisms constructed in this paper are

S. Sachse, R. Weixler

We prove the embedding of $ ISO_q(3) \hook ISU^{ex}_{\sqrt{q}}(2) $ and $ ISO_q(2,1) \hook ISL^{ex}_q(2,R)$ as $^*$-algebras and give a Hilbert space representation of $ISU^{ex}_{\sqrt{q}}(2)$

T. T. S. Kuo, S. Ray, J. Shamanna, R. K. Su

We study a cubic lattice gas model for nuclear matter where each lattice site can be either occupied, by one proton or one neutron, or unoccupied. A nearest-neighbor interaction of the form $ - \sum_{<ij>} J_{ij}τ_{zi} τ_{zj}$ is assumed. Our model is an isospin-1 Ising model, with ${τ_z}$ = (1,0,-1) representing respectively (proton, vacancy, neutron). A ki

Wolfgang Bauer, Alexander Botvina

In two different phase transition models of nuclear fragmentation we show that the emission of pre-equilibrium particles and mixing of events from different classes cannot be ignored in the analysis of nuclear fragmentation data in terms of critical exponents, and we show how the apparent values of the extracted exponents are affected.

O. Benhar, S. Fantoni, N. N. Nikolaev, J. Speth

We use multiple scattering theory to evaluate the $Q^{2}$ dependence of the forward-backward asymmetry, $A_{z}$, of the missing momentum distribution in quasielstic $A(e,e&#39;p)$ scattering, which is expected to be affected by color transparency. The novel features of our analysis are a consistent treatment of the structure of the ejectile state formed afte

S. A. Rakityansky, S. A. Sofianos, K. Amos

A combination of the variable-constant and complex coordinate rotation methods is used to solve the two-body Schrödinger equation. The latter is replaced by a system of linear first-order differential equations, which enables one to perform direct calculation of the Jost function for all complex momenta of physical interest, including the spectral points cor

S. Ogut, K. M. Rabe

We use ab initio pseudopotential total energy calculations with a plane wave basis set to investigate the structural energetics of various phases of polymorphic NbN. Particular attention is given to its recently discovered superconducting phase with a $T_c$ of 16.4 K, reported to have the NbO structure type. Results of total energy calculations show that it

Eric D&#39;Hoker

We review the correspondence between effective actions resulting from non-invariant Lagrangian densities, for Goldstone bosons arising from spontaneous breakdown of a symmetry group G to a subgroup H, and non-trivial generators of the de Rham cohomology of G/H. We summarize the construction of cohomology generators in terms of symmetric tensors with certain

R. W. Gebert, H. Nicolai, P. C. West

Multistring vertices and the overlap identities which they satisfy are exploited to understand properties of hyperbolic Kac Moody algebras, and $E_{10}$ in particular. Since any such algebra can be embedded in the larger Lie algebra of physical states of an associated completely compactified subcritical bosonic string, one can in principle determine the root

Z. Burda, J. -P. Kownacki, A. Krzywicki

A real space renormalization group technique, based on the hierarchical baby-universe structure of a typical dynamically triangulated manifold, is used to study scaling properties of 2d and 4d lattice quantum gravity. In 4d, the $β$-function is defined and calculated numerically. An evidence for the existence of an ultraviolet stable fixed point of the theor

Pietro Antonio Grassi

In this paper the stability and the renormalizability of Yang-Mills theory in the Background Field Gauge are studied. By means of Ward Identities of Background gauge invariance and Slavnov-Taylor Identities the stability of the classical model is proved and, in a regularization independent way, its renormalizability is verified. A prescription on how to buil

Tonatiuh Matos

This is a comment on the article &#34;Integrable Systems in Stringy Gravity&#34; by D. V. Gal&#39;tsov, Phys. Rev. Lett. 74, 2863, (1995).

Peter Cho, Adam Leibovich

Gluon fragmentation represents the dominant source of high energy prompt quarkonia at hadron colliders. Fragmentation approximations break down, however, when a quarkonium&#39;s transverse momentum becomes comparable to its mass. In this paper, we identify a large class of color-octet diagrams that mediate quarkonia production at all energies and reduce to t

A. Pich, J. P. Silva

The recent measurements of the Michel parameters in tau decays enable, for the first time, a thorough analysis of the leptonic sector. In general, in models beyond the Standard Model, these parameters will be altered through changes in the W and Z couplings, and/or through interactions mediated by new gauge bosons. We perform a complete, model independent an

Katsuhiko Suzuki

We study the pion structure function in nuclear medium using the Nambu and Jona-Lasinio model, and its implication for the nuclear pion enhancement of the sea quark distribution in nuclei. By using the operator product expansion, medium effect of the nuclear matter is incorporated in calculations of the twist-2 operators. We find density dependence of the pi

V. Ilyin, A. Pukhov, V. Savrin, A. Semenov

We analyse numerically manifestations of the radiative amplitude zero (RAZ) effect in single leptoquark production associated with hard photon emission. We present some quantitative conclusions on the possibility to distinguish leptoquark charges produced in ep collisions taking account of three-body final state subprocesses and of proton structure functions

M. Consoli, N. M. Stivala, D. Zappala&#39;

We reanalyze the problem of the cosmological constant associated with the phase transition in a self-interacting scalar theory. It is pointed out that the generally accepted ``triviality&#39;&#39; of $(λΦ^4)_4$ implies a first-order phase transition. As a consequence, Spontaneous Symmetry Breaking can be consistent with zero cosmological constant if one assu

K. Hagiwara, S. Matsumoto, R. Szalapski

Extensions of the Standard Model which involve a new scale, $Λ$, may, for energies sufficiently small compared to this new scale, be expressed in terms of operators with energy dimension greater than four. The coefficients of just four SU(2)$\times$U(1)-gauge-invariant energy-dimension-six operators are sufficient to parameterize the contributions of new phy

C. Wieczerkowski, Y. Xylander

We compute moving eigenvalues and the eigenvectors of the linear renormalization group transformation for observables along the renormalized trajectory of the hierarchical non-linear $O(N)$-invariant $σ$-model by means of perturbation theory in the running coupling constant. Moving eigenvectors are defined as solutions to a Callan-Symanzik type equation.

ZEUS Collaboration

This paper presents an analysis of the inclusive properties of diffractive deep inelastic scattering events produced in $ep$ interactions at HERA. The events are characterised by a rapidity gap between the outgoing proton system and the remaining hadronic system. Inclusive distributions are presented and compared with Monte Carlo models for diffractive proce

Jorma Louko

Witten&#39;s formulation of 2+1 gravity is investigated on the nonorientable three-manifold R x (Klein bottle). The gauge group is taken to consist of all four components of the 2+1 Poincare group. We analyze in detail several components of the classical solution space, and we show that from four of the components one can recover nondegenerate spacetime metr

Arturo Echeverría-Enríquez, Miguel C. Muñoz-Lecanda, Narciso Román-Roy

We construct a lagrangian geometric formulation for first-order field theories using the canonical structures of first-order jet bundles, which are taken as the phase spaces of the systems in consideration. First of all, we construct all the geometric structures associated with a first-order jet bundle and, using them, we develop the lagrangian formalism, de

Rodolfo Cuerno, Kent Baekgaard Lauritsen

We have analyzed the Kuramoto-Sivashinsky equation with a stochastic noise term through a dynamic renormalization group calculation. For a system in which the lattice spacing is smaller than the typical wavelength of the linear instability occurring in the system, the large-distance and long-time behavior of this equation is the same as for the Kardar-Parisi

Daniel Sanchez-Portal, Emilio Artacho, Jose M. Soler

The projection of the eigenfunctions obtained in standard plane-wave first-principle electronic-structure calculations into atomic-orbital basis sets is proposed as a formal and practical link between the methods based on plane waves and the ones based on atomic orbitals. Given a candidate atomic basis, ({\it i}) its quality is evaluated by its projection in

Xuejun Zhu, Steven G. Louie

The two-dimensional Wigner crystals are studied with the variational quantum Monte Carlo method. The close relationship between the ground-state wavefunction and the collective excitations in the system is illustrated, and used to guide the construction of the ground-state wavefunction of the strongly correlated solid. Exchange, correlation, and magnetic fie

Boris Levitan, Eytan Domany

We introduce a topological model for the evolution of 2d soap froth. The topological rearrangements (T2 processes) are deterministic (unlike the standard stochastic model): the final topology depends on the areas of the neighboring cells. The new model gives agreement with experiments in the transient regime, where the previous models failed qualitatively, a

Jukka A. Ketoja, Indubala I. Satija

The localized eigenstates of the Harper equation exhibit universal self-similar fluctuations once the exponentially decaying part of a wave function is factorized out. For a fixed quantum state, we show that the whole localized phase is characterized by a single strong coupling fixed point of the renormalization equations. This fixed point also describes the

Shin&#39;ya Tokizaki, Yoshio Kuramoto

The ground state as well as low-lying excitations in a 2D electron system in strong magnetic fields and a parabolic potential is investigated by the variational Monte Calro method. Trial wave functions analogous to the Laughlin state are used with the power-law exponent as the variational parameter. Finite size scaling of the excitation energy shows that the

Alexander Sokol

I review recent work on magnetic dynamics of the high temperature superconductors using a model that combines two weakly interacting species of low-energy excitations: the antiferromagnetic spin waves which carry spin-1 and no charge, and Fermi-liquid-like quasiparticles which carry spin-1/2 and charge e. The model allows conversion of spin waves into electr

Biman B. Nath, Masashi Chiba

Following the recent suggestion that it is dwarf galaxies in clusters -- as opposed to large ellipticals -- that provide the intracluster gas, we estimate the metallicity of the intracluster medium (ICM) in such a case. We derive analytical expressions for the fraction of mass of dwarf galaxies that is ejected, and estimate the metallicity of the resulting i

F J Summers, Marc Davis, August E. Evrard

This paper examines several methods of tracing galaxies in N-body simulations and their effects on the derived galaxy statistics, especially measurements of velocity bias. Using two simulations with identical initial conditions, one following dark matter only and the other following dark matter and baryons, both collisionless and collisional methods of traci

J. C. R. Magueijo

In this paper we show how the prediction of CMBR angular power spectra $C_l$ in non-Gaussian theories is affected by a cosmic covariance problem, that is $(C_l,C_{l&#39;})$ correlations impart features on any observed $C_l$ spectrum which are absent from the average $C^l$ spectrum. Therefore the average spectrum is rendered a bad observational prediction, an

Matthias Bartelmann, Abraham Loeb

Damped Lyman-alpha absorbers are believed to be associated with galactic disks. We show that gravitational lensing can therefore affect the statistics of these systems. First, the magnification bias due to lensing raises faint QSOs above a given magnitude threshold and thereby enhances the probability for observing damped absorption systems. Second, the bend

G. B. Dalton

The APM Cluster Survey was based on a modification of Abell&#39;s original classification scheme for galaxy clusters. Here we discuss the results of an investigation of the stability of the statistical properties of the cluster catalogue to changes in the selection parameters. For a poor choice of selection parameters we find clear indications of line-of-sig

S. Ghizzardi, S. A. Bonometto

We discuss the phase--space distribution of $μ$ neutrinos if $τ$ neutrinos are unstable and decay into $ν_μ+ scalar$. If this scalar is a familon or a Majoron, in the generic case the $ν_μ$ background is NOT the straightforward overlap of neutrinos of thermal and decay origins. A delay in $ν_τ$ decay, due to the Pauli exclusion principle, can modify it in a

W. Steffen, J. A. Zensus, T. P. Krichbaum, A. Witzel

We present a simple model for the apparent superluminal motion along curved trajectories of features observed in the compact radio jet of the quasar 3C345. The model is inspired by the magneto-hydrodynamic approach of Camenzind (1986), and assumes a conical geometry of the jet within about three milliarcseconds of the radio core. Simultaneous conservation of

Philippe Crane

A simple model of the nucleus of M31 based on {\it HST} images and ground based spectroscopy is used to investigate the properties of the double nucleus in M31. The model reproduces the general properties observed in the nucleus of M31. In particular, it produces symmetric rotation curves, and shifts of the velocity dispersion peak in the sense observed. Wit

Dongsu Ryu, T. W. Jones, Adam Frank

We present for astrophysical use a multi-dimensional numerical code to solve the equations for ideal magnetohydrodynamics (MHD). It is based on an explicit finite difference method on an Eulerian grid, called the Total Variation Diminishing (TVD) scheme, which is a second-order-accurate extension of the Roe-type upwind scheme. Multiple spatial dimensions are

Ravi P. Pilla, Jacob Shaham

We study the emission and absorption spectra due to various photon and pair processes in a non-equilibrium pair plasma containing a significant density of photons. We present here some preliminary results from Monte-Carlo simulations. These investigations are likely to be useful in understanding the radiation and relaxation mechanisms in non-thermal gamma-ra

Ronald Fintushel, Ronald Stern

In this paper we introduce a surgical procedure, called a rational blowdown, for a smooth 4-manifold X and determine how this procedure affects both the Donaldson and Seiberg-Witten invariants of X.

N. Hata, R. J. Scherrer, G. Steigman, D. Thomas

A new evaluation of the constraint on the number of light neutrino species (N_nu) from big bang nucleosynthesis suggests a discrepancy between the predicted light element abundances and those inferred from observations, unless the inferred primordial 4He abundance has been underestimated by 0.014 +/- 0.004 (1 sigma) or less than 10% (95%C.L.) of 3He survives

R. Mohayaee, L. Wenham

The one-loop anomalies for chiral $W_{3}$ gravity are derived using the Fujikawa regularisation method. The expected two-loop anomalies are then obtained by imposing the Wess-Zumino consistency conditions on the one-loop results. The anomalies found in this way agree with those already known from explicit Feynman diagram calculations. We then directly verify

G. -M. Rignanese, Ph. Ghosez, J. -C. Charlier, J. -P. Michenaud

We present a new technique aimed at preventing plane-wave based total energy and stress calculations from the effect of abrupt changes in basis set size. This s cheme relies on the interpolation of energy as a function of the number of plane waves, and on a scaling hypothesis that allows to perform the interpolation for a unique reference volume. From a theo

Luis E. Ibanez

I discuss several issues concerning the use of string models as unified theories of all interactions. After a short review of gauge coupling unification in the string context, I discuss possible motivations for the construction of $SU(5)$ and $SO(10)$ String-GUTs. I describe the construction of such String-GUTs using different orbifold techniques and emphasi

Matteo Marsili

Directed polymers in random media are studied using results of the asymptotic theory of extreme statistics. Despite the strong correlation, one can recover the behavior of independent random variables for high dimensions, using a result which requires only a control of pairwise correlation, and focussing on ensembles of low energy directed polymers.

B. de Wit, A. Van Proeyen

We describe special Kahler geometry, special quaternionic manifolds, and very special real manifolds and analyze the structure of their isometries. The classification of the homogeneous manifolds of these types is presented.

G. Modanese

Under special conditions (Meissner-effect levitation in a high frequency magnetic field and rapid rotation) a disk of high-$T_c$ superconducting material has recently been found to produce a weak shielding of the gravitational field. We show that this phenomenon has no explanation in the standard gravity theories, except possibly in the non-perturbative Eucl

M. J. Lercher, J. M. Wheatley

The $\mathbf k$-dependent electronic momentum relaxation rate due to Umklapp scattering from antiferromagnetic spin fluctuations is studied within a renormalized mean-field approach to an extended $t-J$ model appropriate to YBa$_2$Cu$_3$O$_{7-x}$ and other cuprates. Transport coefficients are calculated in a relaxation time approximation. We compare these re

R. N. Faustov, V. O. Galkin, A. Yu. Mishurov

The exclusive semileptonic $B\to π(ρ) eν$ decays are studied in the framework of the relativistic quark model based on the quasipotential approach in quantum field theory. The large recoil momentum of the final $π(ρ)$ meson allows for the expansion of the decay form factors at $q^2=0$ in the inverse powers of $b$-quark mass. This considerably simplifies the

J. Avan, O. Babelon, E. Billey

We quantize the spin Calogero-Moser model in the $R$-matrix formalism. The quantum $R$-matrix of the model is dynamical. This $R$-matrix has already appeared in Gervais-Neveu&#39;s quantization of Toda field theory and in Felder&#39;s quantization of the Knizhnik-Zamolodchikov-Bernard equation.

Lena Stromback

A common feature of recent unification-based grammar formalisms is that they give the user the ability to define his own structures. However, this possibility is mostly limited and does not include nonmonotonic operations. In this paper we show how nonmonotonic operations can also be user-defined by applying default logic (Reiter 1980) and generalizing previ

Haret C. Rosu, M. Reyes, K. B. Wolf, O. Obregón

We work out the second solution of the DO superpotentials in the $R_0=0$ sector.

M. V. Altaiski

The self-similar representation for the Schrödinger equation is derived.

Robert B. Griffiths

Omnes&#39; interpretation of quantum mechanics is summarized, and compared with other consistent-history approaches by Gell-Mann and Hartle, and by Griffiths.

Laura M. Morato, Lorenza Viola

We revisit the classical approach of comoving coordinates in relativistic hydrodynamics and we give a constructive proof for their global existence under suitable conditions which is proper for stochastic quantization. We show that it is possible to assign stochastic kinematics for the free relativistic spinless particle as a Markov diffusion globally define

C. Fronsdal, A. Galindo

Multiparameter quantum gl(N) is not a rigid structure. This paper defines an essential deformation as one that cannot be interpreted in terms of a similarity transformation, nor as a perturbation of the parameters. All the equivalence classes of first order essential deformations are found, as well as a class of exact deformations. This work provides quantiz

J. Donin, S. Shnider

Let $V$ be a finite dimensional vector space. Given a decomposition $V\otimes V=\oplus_i^n I_i$, define $n$ quadratic algebras $(V, J_m)$ where $J_m=\oplus_{i\neq m} I_i$. This decomposition defines also the quantum semigroup $M(V;I_1,...,I_n)$ which acts on all these quadratic algebras. With the decomposition we associate a family of associative algebras $A

Christian Fronsdal

The Universal T-matrix is the capstone of the structure that consists of a quantum group and its dual, and the central object from which spring the T-matrices (monodromies) of all the associated integrable models. A closed expression is obtained for the case of multiparameter (twisted) quantum $gl(N)$. The factorized nature of standard quantum groups, that a

Michitomo Nishizawa

A $q$-analogue of the multiple gamma functions is introduced, and is shown to satisfy the generalized Bohr-Morellup theorem. Furthermore we give some expressions of these function.

Victor Ginzburg, Mikhail Kapranov, Eric Vasserot

In this paper we explain the parallelism in the classification of three different kinds of mathematical objects: (i) Classical r-matrices. (ii) Generalized cohomology theories that have Chern classes for complex vector bundles. (iii) 1-dimensional formal groups. The main point of the paper is a construction of the elliptic algebra associated to Belavin&#39;s

Yang Lu, R. D. Amado

We use classical/large Nc (number of colors) QCD to study nucleon--antinucleon annihilation at rest. We include pion, rho and omega fields in the classical dynamics, starting from the nonlinear sigma model. We begin with a spherical blob of pionic matter with zero baryon number and energy of twice the nucleon mass. This evolves according to the classical dyn

X. W. Pan, T. T. S. Kuo, M. Vallieres, D. H. Feng

Some fundamental Nucleon-Nucleon interactions and their applications to finite nuclei are reviewed. Results for the few-body systems and from Shell-Model calculations are discussed and compared to point out the advantages and disadvantages of the different Nucleon-Nucleon interactions. The recently developed Drexel University Shell Model (DUSM) code is menti

Koji Fujiwara

We study the second bounded cohomology of an amalgamated free product of groups, and an HNN extension of a group. As an application, we have a group with infinitely many ends has infinite dimensional second bounded cohomology.

R. Amorim, J. Barcelos-Neto

We make a comparative study of chiral-boson theories in the Florenani-Jackiw (FJ) and linear constraint formulations. A special attention is given to the case with an improved way of implementing the linear constraint. We show that it has the same spectrum of the FJ formulation.

R. Amorim, J. Barcelos-Neto

We use the BV quantization method for a theory with coupled tensor and vector gauge fields through a topological term. We consider in details the reducibility of the tensorial sector as well as the appearance of a mass term in the effective vectorial theory .

J. C. Brunelli, Ashok Das

In this paper, we review various properties of the supersymmetric Two Boson (sTB) system. We discuss the equation and its nonstandard Lax representation. We construct the local conserved charges as well as the Hamiltoniam structures of the system. We show how this system leads to various other known supersymmetric integrable models under appropriate field re

Christof Gattringer

QED_2 with mass and flavor has in common many features with QCD, and thus is an interesting toy model relevant for four dimensional physics. The model is constructed using Euclidean path integrals and mass perturbation series. The vacuum functional is carefully decomposed into clustering states being the analogue of the theta-vacuum of QCD. Finally the clust

Phil E. Gibbs

I examine various aspects of event-symmetric physics such as phase changes, symmetry breaking and duality by studying a number of simple toy-models.

R. G. Leigh, M. J. Strassler

We discuss electric-magnetic duality in two new classes of supersymmetric Yang-Mills theories. The models have gauge group $Sp(2\nc)$ or $SO(\nc)$ with matter in both the adjoint and defining representations. By perturbing these theories with various superpotentials, we find a variety of new infrared fixed points with dual descriptions. This work is compleme

Alex Kovner, Larry McLerran, Heribert Weigert

We consider the production of high transverse momentum gluons in the McLerran-Venugopalan model of nuclear structure functions. We explicitly compute the high momentum component in this model. We compute the nuclear target size $A$ dependence of the distribution of produced gluons.

A. A. Maslikov, I. A. Naumov, G. G. Volkov

The one of the main points of the investigations in high energy physics is to study the next chain: a law of the quark and lepton mass spectra $\rightarrow $ the puzzles of the quark and lepton family mixing $\rightarrow $ a possible new family dynamics. The new family symmetry dynamics might be connected to the existence of some exotic gauge or matter field

V. M. Braun

I give a short review of the relation of infrared renormalons in QCD and higher twist effects, with the emphasis on possible applications. In particular, I present estimates of renormalon-induced uncertainties in deep inelastic sum rules and explain how the renormalons can potentially be used to unravel the structure of nonperturbative effects in complicated

A. A. Pivovarov

A kind of asymptotic expansion for calculation of the (para)positronium decay rate is formulated. The method is completely relativistic and gauge invariant. The expansion goes over the inverse square of relative momentum $k$ of two photons in Euclidean region and the actual width is determined at $k^2=-m^2$, $m$ being the electron mass.

G. Couture, H. König

We present a detailed and complete calculation of the loop corrections to the mass difference $Δm_{B_d^0}/m_{B_d^0}$. We include charginos and scalar up quarks as well as gluinos and scalar down quarks on the relevant loop diagrams. We include the mixings of the charginos and of the scalar partners of the left and right handed quarks. We find that the gluino

Dongsheng Liu

We analyze forward-backward charge asymmetry of the lepton production in rare decays $B\rightarrow X_s l^+l^-$ and $B\rightarrow K^* l^+l^-$, including vector-resonance effects. Certain regions of phase space, in which the asymmetry is sensitive to individual short-distance coefficients, are pointed out. In particular, we suggest a method to test the couplin

Paul Derwent

Reporting, for the CDF and D0 collaborations, results from the 1992-93 Fermilab Tevatron Collider run concerning charm and beauty quark production and beauty meson decay properties.

C. Barrabes, B. Boisseau, W. Israel

We analyze the relativistic dynamical properties of Keplerian and non-Keplerian circular orbits in a general axisymmetric and stationary gravitational field, and discuss the implications for the stability of co- and counter-rotating accretion disks and tori surrounding a spinning black hole. Close to the horizon there are orbital peculiarities which can seem

Viqar Husain, Erik A. Martinez, Dario Nunez

We give an approach to studying the critical behaviour that has been observed in numerical studies of gravitational collapse. These studies suggest, among other things, that black holes initially form with infinitesimal mass. We show generally how a black hole mass formula can be extracted from a transcendental equation. Using our approach, we give an explic

Maurice H. P. M. van Putten, Douglas M. Eardley

Graviational radiation is described by canonical Yang-Mills wave equations on the curved space-time manifold, together with evolution equations for the metric in the tangent bundle. The initial data problem is described in Yang-Mills scalar and vector potentials, resulting in Lie-constraints in addition to the familiar Gauss-Codacci relations.

Lee Smolin

Several problems in cosmology and astrophysics are described in which critical phenomena of various types may play a role. These include the organization of the disks of spiral galaxies, various aspects of the problem of structure formation in icosmology, the problem of the selection of initial conditions and parameters in particle physics and cosmology and

M. Tsuda, T. Shirafuji, H. -j. Xie

It has been shown for low-spin fields that the use of only the self-dual part of the connection as basic variable does not lead to extra conditions or inconsistencies. We study whether this is true for more general chiral action. We generalize the chiral gravitational action, and assume that half-integer spin fields are coupled with torsion linearly. The equ

M. Caselle

We discuss the distribution of transmission eigenvalues in the strongly localized regime in the presence of both a magnetic field and spin--orbit scattering. We show that, under suitable conditions, this distribution can be described by a new universality class labelled not only by the index $β$ but also by a new index $η$. This result is obtained by mapping

Hiroki Nakano, Minoru Takahashi

Quantum Heisenberg ferromagnets with long-range interactions decayin as $1/r^p$ in one and two dimensions are investigated by means of the Green&#39;s function method. It is shown that there exists a finite-temperature phase transition in the region $d<p<2 d$ for the $d$-dimensional case and that no transitions at any finite temperature exist for $p\ge 2 d$;

Massimo Poesio

I explore some of the issues that arise when trying to establish a connection between the underspecification hypothesis pursued in the NLP literature and work on ambiguity in semantics and in the psychological literature. A theory of underspecification is developed `from the first principles&#39;, i.e., starting from a definition of what it means for a sente

G. Benfatto, G. Gallavotti, L. Lebowitz

We investigate a spinless fermion system on a one dimensional lattice interacting locally with the optical modes of a quantized phonon field: the Holstein model. The system is shown to have a disordered ground state, for small enough coupling, at any density. This is in contrast to the non quantized phonon case, the static Holstein model, which at half filli