May 1995 arXiv papers — page 9

A. A. Tseytlin

We review explicitly known exact $D=4$ solutions with Minkowski signature in closed bosonic string theory. Classical string solutions with space-time interpretation are represented by conformal sigma models. Two large (intersecting) classes of solutions are described by gauged WZW models and `chiral null models' (models with conserved chiral null current

M. K. Hari Menon, Deepak Dhar

We study a model of stochastic deposition-evaporation with recombination, of three species of dimers on a line. This model is a generalization of the model recently introduced by Barma {\it et. al.} (1993 {\it Phys. Rev. Lett.} {\bf 70} 1033) to $q\ge 3$ states per site. It has an infinite number of constants of motion, in addition to the infinity of conserv

T. Blum, A. J. McKane

We investigate variational methods for finding approximate solutions to the Fokker-Planck equation, especially in cases lacking detailed balance. These schemes fall into two classes: those in which a Hermitian operator is constructed from the (non-Hermitian) Fokker-Planck operator, and those which are based on soluble approximations to this operator. The var

Jean-Loup Gervais, Mikhail V. Saveliev

In the present paper we obtain some integrable generalisations of the Toda system generated by flat connection forms taking values in higher ${\bf Z}$--grading subspaces of a simple Lie algebra, and construct their general solutions. One may think of our systems as describing some new fields of the matter type coupled to the standard Toda systems. This is of

M. Jimbo, R. Kedem, H. Konno, T. Miwa

A level-0 action of $U_q(\widehat{sl}_2)$ is defined on the sum of level-1 irreducible highest weight modules. With the aid of the affine Hecke algebras, this action is realized on the basis created by the vertex operators. This is a $q$-analogue of the Yangian symmetry in conformal field theory.

Michael Frank

Let $\cal M$ be a Banach C*-module over a C*-algebra $A$ carrying two $A$-valued inner products $< .,. >_1$, $<.,. >_2$ which induce equivalent to the given one norms on $\cal M$. Then the appropriate unital C*-algebras of adjointable bounded $A$-linear operators on the Hilbert $A$-modules $\{ {\cal M}, < .,. >_1 \}$ and $\{ {\cal M}, < .,. >_2 \}$ are shown

M. D&#39;Elia, F. Farchioni, A. Papa

We study scaling properties and topological aspects of the 2--d O(3) non--linear $σ$--model on the lattice with the parametrized fixed point action recently proposed by P.~Hasenfratz and F.~Niedermayer. The behavior of the mass gap confirms the good properties of scaling of the fixed point action. Concerning the topology, lattice classical solutions are prov

Keith R. Dienes, Alon E. Faraggi

We discuss the unification of gauge couplings within the framework of a wide class of realistic free-fermionic string models which have appeared in the literature, including the flipped SU(5), SO(6)xSO(4), and various SU(3)xSU(2)xU(1) models. If the matter spectrum below the string scale is that of the Minimal Supersymmetric Standard Model (MSSM), then strin

P. Garbaczewski, J. R. Klauder, R. Olkiewicz

The main purpose of the paper is an essentially probabilistic analysis of relativistic quantum mechanics. It is based on the assumption that whenever probability distributions arise, there exists a stochastic process that is either responsible for temporal evolution of a given measure or preserves the measure in the stationary case. Our departure point is th

Yuhai Tu, Herbert Levine

We propose a mean-field model for describing the averaged properties of a class of stochastic diffusion-limited growth systems. We then show that this model exhibits a morphology transition from a dense-branching structure with a convex envelope to a dendritic one with an overall concave morphology. We have also constructed an order parameter which describes

H. Eduardo Roman, Lorenzo Pavesi

A simple lattice model describing the recombination dynamics in visible light emitting porous Silicon is presented. In the model, each occupied lattice site represents a Si crystal of nanometer size. The disordered structure of porous Silicon is modeled by modified random percolation networks in two and three dimensions. Both correlated (excitons) and uncorr

Cumrun Vafa, Edward Witten

We test type IIA-heterotic string duality in six dimensions by showing that the sigma model anomaly of the heterotic string is generated by a combination of a tree level and a string one-loop correction on the type IIA side.

F. Schaposnik

We discuss recent results on bosonization in $d \geq 2$ space-time dimensions by giving a very simple derivation for the bosonic representation of the original free fermionic model both in the abelian and non-abelian cases. We carefully analyse the issue of symmetries in the resulting bosonic model as well as the recipes for bosonization of fermion currents

P. Cea, M. Consoli, L. Cosmai, R. Fiore

We present a precise lattice computation of the slope of the effective potential for massless $(λΦ^4)_4$ theory in the region of bare parameters indicated by the Brahm&#39;s analysis of lattice data. Our results confirm the existence on the lattice of a remarkable phase of $(λΦ^4)_4$ where Spontaneous Symmetry Breaking is generated through ``dimensional tran

Ernest Ma, Daniel Ng

If the $R_b$ excess at LEP is real, then any explanation in terms of renormalizable loop corrections leads to important new decay modes of the $t$ quark and suppresses the $t \to bW$ branching ratio. In the two-Higgs-doublet model, the branching ratio of $Z \to b \bar b$ + a light boson which decays itself predominantly into $b \bar b$ is at least of order $

D. -U. Jungnickel, C. Wetterich

The scale dependence of an effective average action for mesons and quarks is described by a nonperturbative flow equation. The running couplings lead to spontaneous chiral symmetry breaking. We argue that for strong Yukawa coupling between quarks and mesons the low momentum physics is essentially determined by infrared fixed points. This allows us to establi

N. Brambilla, G. M. Prosperi

We derive a confining $ q \bar{q}$ Bethe--Salpeter equation starting from the same assumptions on the Wilson loop integral already adopted in the derivation of a semirelativistic heavy quark potential. We show that, by standard approximations, an effective meson squared mass operator can be obtained from our BS kernel and that, from this, by ${1\over m^2}$ e

A. Moalem, L. Razdolskaja, E. Gedalin

A procedure is proposed which accounts for final state interaction corrections for near threshold meson production in nucleon-nucleon scattering. In analogy with the Watson-Migdal approximation, it is shown that in the limit of extremely strong final state effects, the amplitude factorizes into a primary production amplitude and an elastic scattering amplitu

N. Brambilla, G. M. Prosperi

It is shown that the semirelativistic $q \bar{q}$ potential, the relativistic flux tube model and a confining Bethe--Salpeter equation can be derived from QCD first principles in a unified point of view.

A. H. Hoang, J. H. Kühn, T. Teubner

The rate for the production of a pair of massive fermions in $e^+ e^-$ annihilation plus real or virtual radiation of a pair of massless fermions is calculated analytically. The contributions for real and virtual radiation are displayed separately. The asymptotic behaviour close to threshold and for high energies is given in a compact form. These approximati

M. Consoli, M. Piccolo

We propose a procedure to measure the Z$^{0}$ line shape and take full advantage of the superb performance of the CERN $e^+e^-$ Collider LEP. A precise determination of the total cross section at 5 energies is needed for a model-independent analysis of the data and for a precision test of the QED initial state radiation from the fully inclusive hadronic chan

Chun Liu

A pattern of quark mass hierarchy and CP violation within the framework of low energy supersymmetry is described. By assuming some discrete symmetry among the three families, the quarks of the third family obtain masses at tree level. The second family obtains masses radiatively at one-loop level due to the soft breaking of the family symmetry. At this level

Victor Matveev, Robert Shrock

We present calculations of the complex-temperature zeros of the partition functions for 2D Ising models on the square lattice with spin $s=1$, 3/2, and 2. These give insight into complex-temperature phase diagrams of these models in the thermodynamic limit. Support is adduced for a conjecture that all divergences of the magnetisation occur at endpoints of ar

R. Camporesi, A. Higuchi

The eigenfunctions of the Dirac operator on spheres and real hyperbolic spaces of arbitrary dimension are computed by separating variables in geodesic polar coordinates. These eigenfunctions are used to derive the heat kernel of the iterated Dirac operator on these spaces. They are then studied as cross sections of homogeneous vector bundles, and a group-the

R. Holyst, P. Oswald

The electric field applied perpendicularly to smectic layers breaks the rotational symmetry of the system. Consequently, the elastic energy associated with distortions induced by an edge dislocation diverges logarithmically with the size of the system. In freely suspended smectic films the dislocations in the absence of the electric field are located exactly

T. Blum, A. J. McKane

We apply a number of schemes which variationally improve perturbation theory for the Kardar-Parisi-Zhang equation in order to extract estimates for the dynamic exponent z. The results for the various schemes show the same broad features, giving closer agreement with numerical simulations in low dimensions than self-consistent methods. They do, however, conti

A. Furusaki, K. A. Matveev

We study the transport through a quantum dot coupled to two leads by single-mode point contacts. The linear conductance is calculated analytically as a function of a gate voltage and temperature T in the case when transmission coefficients of the contacts are close to unity. As a function of the gate voltage, the conductance shows Coulomb blockade oscillatio

Nobuo Furukawa

Double-exchange model in infinite dimension is studied as the strong Hund&#39;s coupling limit $J\to\infty$ of the Kondo lattice model. Several quantities such as Green&#39;s function and the d.c.\ conductivity are calculated in analytical forms. Magnetoresistance in lightly doped (La,Sr)MnO$_3$ is reproduced very well.

Robert Dale

Most natural language generation systems embody mechanisms for choosing whether to subsequently refer to an already-introduced entity by means of a pronoun or a definite noun phrase. Relatively few systems, however, consider referring to entites by means of one-anaphoric expressions such as \lingform{the small green one}. This paper looks at what is involved

Fred Popowich

A Shake and Bake machine translation algorithm for Head-Driven Phrase Structure Grammar is introduced based on the algorithm proposed by Whitelock for unification categorial grammar. The translation process is then analysed to determine where the potential sources of inefficiency reside, and some proposals are introduced which greatly improve the efficiency

Stephen Soderland, David Fisher, Jonathan Aseltine, Wendy Lehnert

One of the central knowledge sources of an information extraction system is a dictionary of linguistic patterns that can be used to identify the conceptual content of a text. This paper describes CRYSTAL, a system which automatically induces a dictionary of &#34;concept-node definitions&#34; sufficient to identify relevant information from a training corpus.

Robert Mettin, Thomas Kurz

In this work, we demonstrate the open-loop control of chaotic systems by means of optimized periodic signals. The use of such signals enables us to reduce control power significantly in comparison to simple harmonic perturbations. It is found that the stabilized periodic dynamics can be changed by small, specific alterations of the control signal. Thus, low

P. Garbaczewski, J. R. Klauder, R. Olkiewicz

The main purpose of the paper is an essentially probabilistic analysis of relativistic quantum mechanics. It is based on the assumption that whenever probability distributions arise, there exists a stochastic process that is either responsible for temporal evolution of a given measure or preserves the measure in the stationary case. Our departure point is th

J. F. Bell, M. S. Bessell, B. W. Stappers, M. Bailes

Binary radio pulsars are superb tools for mapping binary orbits, because of the precision of the pulse timing method (Taylor and Weisberg 1989). To date, all orbital parameters for binary pulsars have been derived from observations of the pulsar alone. We present the first observations of the radial velocity variations due to the binary motion of a companion

Wayne Hu, Douglas Scott, Naoshi Sugiyama, Martin White

As the data on CMB anisotropies improve and potential cosmological applications are realized, it will be increasingly important for theoretical calculations to be as accurate as possible. All modern calculations for inflationary-inspired fluctuations involve the numerical solution of coupled Boltzmann equations. There are many assumptions and choices to be m

Dong Lai, Lars Bildsten, Vicky Kaspi

The spin-induced quadrupole moment of a rapidly rotating star changes the orbital dynamics in a binary system, giving rise to advance (or regression) of periastron and precession of the orbital plane. We show that these effects are important in the recently discovered radio pulsar/main sequence star binary system PSR J0045$-$7319, and can reliably account fo

M. Gasperini, M. Giovannini, G. Veneziano

In the inflationary scenarios suggested by string theory, the vacuum fluctuations of the electromagnetic field can be amplified by the time-evolution of the dilaton background, and can grow large enough to explain both the origin of the cosmic magnetic fields and of the observed CMB anisotropy. The normalization of the perturbation spectrum is fixed, and imp

E. Gates, G. Gyuk, M. Turner

For almost twenty years models of the Galaxy have included a dark halo responsible for supporting a substantial fraction of the local rotation velocity and a flat rotation curve at large distances. Estimates of the local halo density range from $2\times 10^{-25}\gcmm3$ to $10\times 10^{-25}\gcmm3$. By careful modeling of the Galaxy, taking account of the evi

Richard Watkins, Hume A. Feldman

We study the implications of a recent estimate of the bulk flow of a sample of galaxies containing supernovae type Ia by Riess, Press, and Kirshner. We find that their results are quite consistent with power spectra from several currently popular models of structure formation, but that the sample is as yet too sparse to put significant constraints on the pow

Andrei Teleman, Christian Okonek

The purpose of this paper is: 1) to explain the Seiberg-Witten invariants, 2) to show that - on a Kähler surface - the solutions of the monopole equations can be interpreted as algebraic objects, namely effective divisors, 3) to give - as an application - a short selfcontained proof for the fact that rationality of complex surfaces is a ${\cal C}^{\infty}$-p

Andrei Teleman, Christian Okonek

The purpose of this note is to give a short, selfcontained proof of the following result: A complex surface which is diffeomeorphic to a rational surface is rational.

Daniel Provost

Gutzwiller&#39;s trace formula and Bogomolny&#39;s formula are applied to a non--specific, non--scalable Hamiltonian system, a two--dimensional anharmonic oscillator. These semiclassical theories reproduce well the exact quantal results over a large spatial and energy range.

S. I. Matveenko, A. R. Bishop, A. Balatsky

We study a one-dimensional, two band model with short range electron-electron repulsions (onsite $U$ and nearest-neighbour $V$ terms) and electron-phonon coupling. We show that there is a region of $U$,$V$ and band filling in which singlet superconductivity fluctuations are dominant. This region is absent without electron-phonon interactions and includes lar

C. F. Baillie, W. Janke, D. A. Johnston, P. Plechac

In a recent paper we found strong evidence from simulations that the Isingantiferromagnet on ``thin&#39;&#39; random graphs - Feynman diagrams - displayed amean-field spin glass transition. The intrinsic interest of considering such random graphs is that they give mean field results without long range interactions or the drawbacks, arising from boundary prob

C. A. Bertulani, L. F. Canto, M. S. Hussein

We study the effects of channel coupling in the excitation of $^{11}Be$ projectiles incident on heavy targets. The contribution to the excitation from the Coulomb and the nuclear fields in peripheral collisions are considered. Our results are compared with recent data on the excitation of the $\halfm$ state in $^{11}Be$ projectiles. We show that the experime

Johan Bijnens, Elisabetta Pallante, Joaquim Prades

Mistake in FORTRAN program corrected. The numerical results and conclusions are changed significantly: We present a calculation of the hadronic light-by-light contributions to the muon $g-2$ in the $1/N_c$ expansion. We have used an Extended NJL model and introduced an explicit cut-off for the high energy region. We have then critically studied the relative

Andr&#39;es P. Zuker, Marianne Dufour

It is shown that the nuclear Hamiltonian can be separated rigorously as ${\cal H}={\cal H}_m+{\cal H}_M.$ For sufficiently smooth forces the monopole part ${\cal H}_m $is entirely responsible for Hartree-Fock selfconsistency and hence saturation properties. The multipole part ${\cal H}_M$ contains the ``residual&#39;&#39; terms - pairing, quadrupole, etc. -

J. Duflo, A. P. Zuker

By assuming the existence of a pseudopotential smooth enough to do Hartree-Fock variations and good enough to describe nuclear structure, we construct mass formulae that rely on general scaling arguments and on a schematic reading of shell model calculations. Fits to 1751 known binding energies for N,Z$\geq 8$ lead to rms errors of 375 keV with 28 parameters

Marianne Dufour, Andrés Zuker

The residual part of the realistic forces ---obtained after extracting the monopole terms responsible for bulk properties--- is strongly dominated by pairing and quadrupole interactions, with important $στ\cdotστ$, octupole and hexadecapole contributions. Their forms differ from the schematic ones through normalizations that lead to a universal $A^{-1/3}$ sc

J. Rau, B. Müller

The transition from reversible microdynamics to irreversible transport can be studied very efficiently with the help of the so-called projection method. We give a concise introduction to that method, illustrate its power by using it to analyze the well-known rate and quantum Boltzmann equations, and present, as a new application, the derivation of a source t

A. P. Zuker, J. Retamosa, A. Poves, E. Caurier

Exact diagonalizations with a realistic interaction show that configurations with four neutrons in a major shell and four protons in another -or the same- major shell, behave systematically as backbending rotors. The dominance of the $q\cdot q$ component of the interaction is explained by an approximate form of SU3 symmetry. It is suggested that these config

E. Caurier, A. Poves, A. P. Zuker, G. Martinez-Pinedo

Through a sequence of large scale shell model calculations, total Gamow-Teller strengths ($S_+$ and $S_-$) in $^{54}$Fe and $^{56}$Fe are obtained. They reproduce the experimental values once the $στ$ operator is quenched by the standard factor of $0.77$. Comparisons are made with recent Shell Model Monte Carlo calculations. Results are shown to depend criti

Tetsuo Hatsuda, Su Houng Lee, Hiroyuki Shiomi

Critical examination is made on the relation between the mass shift of vector mesons in nuclear medium and the vector-meson $-$ nucleon scattering length. We give detailed comparison between the QCD sum rule approach by two of the present authors (Phys. Rev. {\bf C46} (1992) R34) and the scattering-length approach by Koike (Phys. Rev. {\bf C51} (1995) 1488).

Joan Hart, Kenneth Kunen

Let X be a compact Hausdorff space and M a metric space. E_0(X,M) is the set of f in C(X,M) such that there is a dense set of points x in X with f constant on some neighborhood of x. We describe some general classes of X for which E_0(X,M) is all of C(X,M). These include beta N - N, any nowhere separable LOTS, and any X such that forcing with the open subset

I. Juhász, Lajos Soukup

Improving a result of M. Rabus we force a normal, locally compact, 0-dimensional,Frechet-Uryson, initially omega_1-compact and non-compact space X of size omega_2 having the following property: for every open (or closed) set A in X we have |A|<omega_2 or |X\A|<omega_2.

Mirjam Cvetič, Donam Youm

A class of 4-dimensional supersymmetric dyonic black hole solutions that arise in an effective 11-dimensional supergravity compactified on a 7-torus is presented. We give the explicit form of dyonic solutions with diagonal internal metric, associated with the Kaluza-Klein sector as well as the three-form field, and relate them to a class of solutions with a

Valeri V. Dvoeglazov

The amplitudes for boson-boson and fermion-boson interactions are calculated in the second order of perturbation theory in the Lobachevsky space. An essential ingredient of the used model is the Weinberg&#39;s $2(2j+1)$ component formalism for describing a particle of spin $j$, recently developed substantially. The boson-boson amplitude is then compared with

J. C. Brunelli, Ashok Das

We show that the supersymmetric nonlinear Schrödinger equation is a bi-Hamiltonian integrable system. We obtain the two Hamiltonian structures of the theory from the ones of the supersymmetric two boson hierarchy through a field redefinition. We also show how the two Hamiltonian structures of the supersymmetric KdV equation can be derived from a Hamiltonian

P. H. Damgaard, F. De Jonghe, R. Sollacher

In the presence of consistent regulators, the standard procedure of BRST gauge fixing (or moving from one gauge to another) can require non-trivial modifications. These modifications occur at the quantum level, and gauges exist which are only well-defined when quantum mechanical modifications are correctly taken into account. We illustrate how this phenomeno

Matthias Burkardt

An introductory overview on Light-Front quantization, with some emphasis on recent achievements, is given. Light-Front quantization is the most promising and physical tool to study deep inelastic scattering on the basis of quark gluon degrees of freedom. The simplified vacuum structure (nontrivial vacuum effects can only appear in zero-mode degrees of freedo

Chung Wook Kim, JeongHyeon Song

We propose a scale-dependent cosmology in which the Robertson--Walker metric and the Einstein equation are modified in such a way that $Ω_0$, $H_0$ and the age of the Universe all become scale-dependent. Its implications on the observational cosmology and possible modifications of the standard Friedmann cosmology are discussed. For example, the age of the Un

Robert D. Pisarski

I review results on the shift of the $ρ$ meson mass at nonzero temperature in a gauged linear sigma model, under the assumption of strict vector meson dominance. (Based upon a talk presented at the International Workshop on &#34;Chiral Dynamics in Hadrons and Nuclei&#34;, Seoul, Korea, Feb., 1995).

Jusak Tandean

If electroweak symmetry is spontaneously broken by technicolor, there will be technimesons analogous to the mesons of the ordinary strong interactions. One of the lightest technimesons is the technieta $η&#39;_T$ (the analogue of the~$η&#39;$). In this work we consider the possibility of observing it at a linear $e^+e^-$ collider operating in the $γγ$ mode.

G. Couture, M. Gintner, S. Godfrey

We describe a detailed study of the process $e^+e^- \to \ell\nu_\ell q \bar{q}$ and the measurement of tri-linear gauge boson couplings (TGV's) at LEP200 and at a 500~GeV and 1~TeV NLC. We included all tree level Feynman diagrams contributing to the four-fermion final states including gauge boson widths and non-resonance contributions. We employed a maximum

P V Landshoff

In many ways the pomeron is like the photon, but there are important differences. Factorisation allows us to define a pomeron structure function, even though the pomeron is not a particle. Although we have a model for the light-quark content of the pomeron, which led to the prediction that a surprisingly large fraction of events at HERA would have an extreme

Gia Dvali

The current cosmological bound on the invisible axion scale may be avoided in the class of theories in which the gauge coupling constant is determined through the expectation value of some scalar field (e.g. moduli in supergravity and string theories). This leads to the cosmological scenario different from that of the standard invisible axion, since the init

Stephen Godfrey

Quartic vertices provide a window into one of the most important problems in particle physics; the understanding of electroweak symmetry breaking. I survey the various processes that have been proposed to study quartic gauge boson couplings at future $e^+e^-$, $e\gamma$, $\gamma\gamma$, $e^-e^-$, and $pp$ colliders. For the lowest dimension operators that do

I. V. Andreev, R. M. Weiner

It is shown that a one to one correspondence between quantum fields in two different &#34;phases&#34; as might be realized for pions produced from a &#34;hadron liquid&#34; leads to squeezed states. The single and double inclusive cross sections for at chaotic superposition of such states are calculated. The correlation of identical pions is overbunched in c

M. Consoli, Z. Hioki

We update our previous analysis on the Higgs mass $m_h$ and the QCD coupling $α_s(=α_s(M_z))$ by using the LEP data after the 1995 Winter Conferences. For $m_t=180$ GeV we find evidence for a rather large value of the Higgs mass in the range 500-1000 GeV, in agreement with the indications from the W mass.

Tom Banks, Yuval Grossman, Enrico Nardi, Yosef Nir

We investigate Supersymmetric models where neither R parity nor lepton number is imposed. Neutrino masses can be kept highly suppressed compared to the electroweak scale if the $μ$-terms in the superpotential are aligned with the SUSY-breaking bilinear $B$-terms. This situation arises naturally in the framework of horizontal symmetries. The same symmetries s

K. Rybicki, R. Rylko

We study the production characteristics of 557 pairs of charmed hadrons produced in $π^{-}-Cu$\ interactions at 230~GeV/c using a momentum estimator for charmed hadrons with missing decay products. We find, the mean value of the transverse momentum squared of the charmed pairs is $<$\pts$>=(1.98\pm 0.11\pm 0.09)\;$ GeV$^2$/c$^2$, the mean rapidity difference

Yong-Shi Wu, Yue Yu

We achieve a bosonization of one-dimensional ideal gas of exclusion statistics $λ$ at low temperatures, resulting in a new variant of $c=1$ conformal field theory with compactified radius $R=\sqrt{1/λ}$. These ideal excluson gases exactly reproduce the low-$T$ critical properties of Luttinger liquids, so they can be used to characterize the fixed points of t

P. Fendley, A. W. W. Ludwig, H. Saleur

A point contact in a Luttinger liquid couples the left- and right-moving channels, producing shot noise. We calculate exactly the DC shot noise at zero temperature in the out-of-equilibrium steady state where current is flowing. Integrability of the interaction ensures the existence of a quasiparticle basis where quasiparticles scatter ``one by one&#39;&#39;

Boldizsar Janko, Vinay Ambegaokar

We find that if two superconducting islands of different number parity are linked by a tunnel junction the unpaired electron in the odd island has a tendency to tunnel into the even island. This process leads to fluctuations in time of the number parity of each island, giving rise to a random telegraph noise spectrum with a characteristic frequency that has

J. M. P. Carmelo, A. H. Castro Neto, N. M. R. Peres

We find the singular transformation between the electron operator and the pseudoparticle operators for the Hubbard chain. We generalize the concept of quasiparticle to one-dimensional electronic systems which in 1D refers to many-pseudoparticle objects. We obtain explicit results for the electron renormalization factor, self energy, and vertex functions at t

A. De Martino, R. Musto

We show that a Coulomb gas Vertex Operator representation of 2D Conformal Field Theory gives a complete description of abelian Hall fluids: as an euclidean theory in two space dimensions leads to the construction of the ground state wave function for planar and toroidal geometry and characterizes the spectrum of low energy excitations; as a $1+1$ Minkowski t

I. L. Aleiner, L. I. Glazman

We present an effective theory describing the low-energy properties of an interacting 2D electron gas at large non-integer filling factors $ν\gg 1$. Assuming that the interaction is sufficiently weak, $r_s < 1$, we integrate out all the fast degrees of freedom, and derive the effective Hamiltonian acting in the Fock space of the partially filled Landau level

Wlodek Zadrozny

We define {\em semantic complexity} using a new concept of {\em meaning automata}. We measure the semantic complexity of understanding of prepositional phrases, of an &#34;in depth understanding system&#34;, and of a natural language interface to an on-line calendar. We argue that it is possible to measure some semantic complexities of natural language proce

Carl de Marcken

We present work-in-progress on the machine acquisition of a lexicon from sentences that are each an unsegmented phone sequence paired with a primitive representation of meaning. A simple exploratory algorithm is described, along with the direction of current work and a discussion of the relevance of the problem for child language acquisition and computer spe

Gerhard Hanrieder, Guenther Goerz

In this paper we describe the linguistic processor of a spoken dialogue system. The parser receives a word graph from the recognition module as its input. Its task is to find the best path through the graph. If no complete solution can be found, a robust mechanism for selecting multiple partial results is applied. We show how the information content rate of

David R. Alves, Kem H. Cook

We have identified 4 Cepheids and 5 Miras using KPNO 4m BVRI images of an outer field in M101. The Cepheid and Mira periods range from 30 to 60 days and 350 to 800 days, respectively. We derive independent Cepheid and Mira distance moduli that agree within experimental uncertainties. We find a true distance modulus of 29.08 +- 0.13 mag.

Dan Kiselman, Åke Nordlund

We study the formation of O I and OH spectral lines in three-dimensional hydrodynamic models of the solar photosphere. The line source function of the O I 777 nm triplet is allowed to depart from local thermodynamic equilibrium (LTE), within the two-level-atom approximation. Comparison with results from 1D models show that the 3D models alleviate, but do not

T. Nakamura, Y. Suto

We present a method to compute the probability distribution function of the (true) Hubble constant and the age of the universe, given the estimate of the Hubble constant in our nearby galaxy samples. Our method takes into account both the observational errors and the cosmic variance, and enables to quantitatively compute the constraints on the cosmological m

Ch. Okonek, A. Teleman

We introduce coupled Seiberg-Witten equations, and we prove, using a generalized vortex equation, that, for Kaehler surfaces, the moduli space of solutions of these equations can be identified with a moduli space of holomorphic stable pairs. In the rank 1 case, one recovers Witten&#39;s result identifying the space of irreducible monopoles with a moduli spac

Ch. Okonek, A. Teleman

We give a short proof for the fact that rationality of complex surfaces is a property depending only on the differential structure. Our proof uses the new Seiberg-Witten invariants.

Lucian Badescu

Using results of Hironaka-Matsumura and Faltings, we prove a strong version of the well known Fulton-Hansen connectivity theorem for weighted projective spaces. As a consequence we get the following result. If $Y$ is an irreducible subvariety of the $n$-dimensional projective space (over a field of arbitrary characteristic), then the diagonal embedding $Δ_Y$

D. Raparia

The Radio-Frequency Quadrupole (RFQ) has a FODO lattice and Drift-Tube-Linacs (DTL) in general also have FODO lattices. Therefore the natural solution for the matching between these is a FODO lattice. For matching in all three planes one then needs sixteen degrees of freedom. However, different requirements, depending on the applications, may change this sol

J. W. Maluf, A. Kneip

The energy density of asymptotically flat gravitational fields can be calculated from a simple expression involving the trace of the torsion tensor. Integration of this energy density over the whole space yields the ADM energy. Such expression can be justified within the framework of the teleparallel equivalent of general relativity, which is an alternative

I. Krichever, A. Zabrodin

Action-angle type variables for spin generalizations of the elliptic Ruijsenaars-Schneider system are constructed. The equations of motion of these systems are solved in terms of Riemann theta-functions. It is proved that these systems are isomorphic to special elliptic solutions of the non-abelian 2D Toda chain. A connection between the finite gap solutions

J. L. Hewett

Constraints placed on physics beyond the Standard Model from the recent CLEO observation of the inclusive decay $B\to X_sγ$ are summarized. Further searches for new physics using the process $B\to X_s\ell^+\ell^-$ are discussed. {Presented at the {\it International Workshop on B Physics: Physics Beyond the Standard Model at the B Factory}, Nagoya, Japan, Oct

J. L. Hewett

We consider the prospect of using the charm system as a laboratory for probing new physics. The theoretical expectations for rare charm meson decays, $D^0-bar D^0$ mixing, and charm quark asymmetries in $Z$ decays are examined in the Standard Model. The effects of new physics from several classes of non-standard dynamical models are summarized for these phen

A. Lazarian

Paramagnetic alignment of non-spherical dust grains rotating at thermal velocities is studied. The analytical solution is found for the alignment measure of oblate grains. Perturbative approach is used for solving the problem. It is shown that even the first approximation of the suggested iteration procedure provides the accuracy well within one percent of t

H. -Thomas Janka

The neutrino signal from SN~1987A provides an excellent opportunity to constrain physical theories for matter at extreme conditions and properties of particles that are produced in supernova (SN) cores. Phase transitions in the supranuclear equation of state (EOS) may change the cooling history of the collapsed stellar core and may even lead to a collapse of

Ron Donagi

This is a survey of various results about spectral covers and their relationship to Higgs bundles. To a G-principal Higgs bundle on a variety S corresponds a cameral cover \widetilde{S} of S (a W-Galois cover, where W is the Weyl group of G) together with a sheaf on \widetilde{S} which in simple cases is a line bundle, and is W-equivariant up to certain twis

Stephen Mrenna, G. L. Kane, Graham D. Kribs, James D. Wells

We study the most promising signals of Constrained Minimal Supersymmetry detectable at a luminosity upgraded 2 TeV Fermilab Tevatron collider. Using a full event-level Monte Carlo based on Pythia/Jetset, we simulate the trilepton signal examining in detail the effect of constraints on the parameter space. We also simulate the monolepton and dilepton signals,

Dae-Yup Song

Using the effective potential, the large-$N$ nonlinear $O(N)$ sigma model with the curvature coupled term is studied on $S^2\times R^1$. We show that, for the conformally coupled case, the dynamical mass generation of the model in the strong-coupled regime on $R^3$ takes place for any finite scalar curvature (or radius of the $S^2$). If the coupling constant

Josef Sollfrank, Ulrich Heinz

We review the progress in understanding the strange particle yields in nuclear collisions and their role in signalling quark-gluon plasma formation. We report on new insights into the formation mechanisms of strange particles during ultrarelativistic heavy-ion collisions and discuss interesting new details of the strangeness phase diagram. In the main part o

J. Mares, E. Friedman, A. Gal, B. K. Jennings

Strong interaction level shifts and widths in $Σ^-$ atoms are analyzed by using a $Σ$ nucleus optical potential constructed within the relativistic mean field approach. The analysis leads to potentials with a repulsive real part in the nuclear interior. The data are sufficient to establish the size of the isovector meson--hyperon coupling. Implications to $Σ

Avinash Khare

In this article we review some of the recent advances regarding the charged vortex solutions in abelian and nonabelian gauge theories with Chern-Simons (CS) term in two space dimensions. Since these nontrivial results are essentially because of the CS term, hence, we first discuss in some detail the various properties of the CS term in two space dimensions.

B. Bagchi, S. N. Biswas, Avinash Khare, P. K. Roy

We discuss in detail the parasupersymmetric quantum mechanics of arbitrary order where the parasupersymmetry is between the normal bosons and those corresponding to the truncated harmonic oscillator. We show that even though the parasusy algebra is different from that of the usual parasusy quantum mechanics, still the consequences of the two are identical. W