September 2000 arXiv papers — page 9

Ludger Hannibal, Jens Warkall

The response of a massive body to gravitational waves is described on the microscopic level. The results shed a new light on the commonly used oscillator model. It is shown that apart from the non-resonant tidal motion the energy transfer from a gravitational wave to an electromagnetically coupled body is in general restricted to the surface, whereas gravita

Christof Monz

This paper describes how automated deduction methods for natural language processing can be applied more efficiently by encoding context in a more elaborate way. Our work is based on formal approaches to context, and we provide a tableau calculus for contextual reasoning. This is explained by considering an example from the problem area of presupposition pro

Christof Monz, Maarten de Rijke

This paper applies resolution theorem proving to natural language semantics. The aim is to circumvent the computational complexity triggered by natural language ambiguities like pronoun binding, by interleaving pronoun binding with resolution deduction. Therefore disambiguation is only applied to expression that actually occur during derivations.

Christof Monz, Maarten de Rijke

We present a tableau calculus for reasoning in fragments of natural language. We focus on the problem of pronoun resolution and the way in which it complicates automated theorem proving for natural language processing. A method for explicitly manipulating contextual information during deduction is proposed, where pronouns are resolved against this context du

J. J. Arenzon, F. Ricci-Tersenghi, D. A. Stariolo

The dynamical properties of a three dimensional model glass, the frustrated Ising lattice gas (FILG) are studied by Monte Carlo simulations. We present results of compression experiments, where the chemical potential is either slowly or abruptly changed, as well as simulations at constant density. One time quantities like density and two time ones like corre

Alain Rochefort, Phaedon Avouris

We investigate the effects of impurity scattering on the conductance of metallic carbon nanotubes as a function of the relative separation of the impurities. First we compute the conductance of a clean (6,6) tube, and the effect of model gold contacts on this conductance. Then, we compute the effect of introducing a single, two, and three oxygen atom impurit

O. Derzhko, T. Krokhmalskii, J. Stolze

Dynamic xx spin pair correlation functions for the isotropic spin-1/2 XY chain are calculated numerically for long open chains in the presence of a transverse magnetic field at finite temperature. As an application we discuss the temperature dependence of the spin-spin relaxation time in PrCl_3.

Tetsuro Nikuni, Allan Griffin

Starting from the quantum kinetic equation for the non-condensate atoms and the generalized Gross-Pitaevskii equation for the condensate, we derive the two-fluid hydrodynamic equations of a trapped Bose gas at finite temperatures. We follow the standard Chapman-Enskog procedure, starting from a solution of the kinetic equation corresponding to the complete l

A. D. Jackson, C. Mejia-Monasterio, T. Rupp, M. Saltzer

We investigate the properties of sparse matrix ensembles with particular regard for the spectral ergodicity hypothesis, which claims the identity of ensemble and spectral averages of spectral correlators. An apparent violation of the spectral ergodicity is observed. This effect is studied with the aid of the normal modes of the random matrix spectrum, which

Oleg Derzhko, Taras Krokhmalskii

Using the numerical approach for a study of the thermodynamic properties of the nonuniform one-dimensional spin-1/2 isotropic XY model in a transverse field we examine different lattice distortions to reveal which spin-Peierls phases are realized in the magnetic chain at zero temperature in the presence of external field.

J. Schnack, Marshall Luban

In an effort to understand the low temperature behavior of recently synthesized molecular magnets we present numerical evidence for the existence of a rotational band in systems of quantum spins interacting with nearest-neighbor antiferromagnetic Heisenberg exchange. While this result has previously been noted for ring arrays with an even number of spin site

E. Montevecchi, J. O. Indekeu

Within the Ginzburg-Landau approach a theoretical study is performed of the effects of confinement on the transition to superconductivity for type-I and type-II materials with surface enhancement. The superconducting order parameter is characterized by a negative surface extrapolation length $b$. This leads to an increase of the critical field $H_{c3}$ and t

Mojca Cepic, Barbara Rovsek, Bostjan Zeks

Phenomenological model of chiral polar smectics is introduced with interactions up to the fourth neighboring layers. The minimization of the free energy gives three stable structures: the ferroelectric Sm C$^*$ phase, the antiferroelectric Sm C$^*_A$ phase and the hellicoidally modulated structure of the Sm C$^*_H$ phase. The phase Sm C$^*_α$ can be recogniz

P. Estrela, A. de Visser, T. Naka, F. R. de Boer

The effect of hydrostatic pressure (p<= 1.8 GPa) on the non-Fermi liquid state of U_2Pt_2In is investigated by electrical resistivity measurements in the temperature interval 0.3-300 K. The experiments were carried out on single-crystals with the current along (I||c) and perpendicular (I||a) to the tetragonal axis. The pressure effect is strongly current-dir

Jean Farago

We propose a systematic method to derive the asymptotic behaviour of the persistence distribution, for a large class of stochastic processes described by a general Fokker-Planck equation in one dimension. Theoretical predictions are compared to simple solvable systems and to numerical calculations. The very good agreement attests the validity of this approac

T. Fujii, A. Furusaki, N. Kawakami, M. Sigrist

We analyze the optically induced Kondo effect in the absorption spectrum for a quantum dot with an even number of electrons, for which the Kondo effect does not occur in the ground state. The Kondo exchange couplings generated for photo-excited states can be either antiferromagnetic or ferromagnetic, which may result in different types of the edge singularit

V. Yu. Irkhin, A. A. Katanin

A generalized supersymmetric representation of the Hubbard operator algebra is considered. This representation is applied to the infinite-U Hubbard model. A mean-field theory which takes into account both on-site and inter-site virtual boson-fermion transitions is developed. Unlike previous approaches, the mean-field theory considered is free from divergence

H. R. Dickel, W. M. Goss, C. G. De Pree

Absorption in the J{K-K+} = 2{11}-2{12} transition of formaldehyde at 2 cm towards the ultracompact HII regions C1 and C2 of W 58 has been observed with the VLA with an angular resolution of ~0.2&#39;&#39; and a velocity resolution of ~1 km/s. The high resolution continuum image of C1 (ON 3) shows a partial shell which opens to the NE. Strong H2CO absorption

Eloy Ayón-Beato, Alberto García, Ricardo Mansilla, César A. Terrero-Escalante

In this paper the Stewart-Lyth inverse problem is rewritten using the comoving scales as the basic parameter. It is shown that some information on the inflaton potential can be obtained from observations taking into account only the scalar power spectrum.

Amri Wandel

The masses of the central black holes of Active Galactic Nuclei estimated by the reverberation virial technique seem to be significantly smaller than predicted from the black hole mass-bulge luminosity relation for massive black holes detected by kinematic methods in less active and normal galaxies. We reexamine the relation for updated data and suggest a fe

D. M. Crenshaw, S. B. Kraemer, J. B. Hutchings, A. C. Danks

We present echelle observations of the intrinsic UV absorption lines in the Seyfert galaxy NGC 4151, which were obtained with the Space Telescope Imaging Spectrograph (STIS) on the Hubble Space Telescope on 1999 July 19. The UV continuum flux at 1450 Angstroms decreased by factor of about four over the previous two years and there was a corresponding dramati

Eric G. Blackman, George B. Field

Mean field dynamos may explain the origin of large scale magnetic fields of galaxies, but controversy arises over the extent of dynamo quenching by the growing field. Here we explain how apparently conflicting results may be mutually consistent, by showing the role of magnetic helicity conservation and boundary terms usually neglected. We estimate the associ

John A. Tomsick, Philip Kaaret

We present a study of the properties of strong 0.8-3.0 Hz quasi-periodic oscillations (QPOs) that occurred during 1997 RXTE observations of the microquasar GRS 1915+105 in the low-hard state. The high count rates allow us to track individual QPO peaks, and we exploit this to develop a QPO folding technique. In contrast to previous QPO studies with RXTE, we e

T. Venturi, D. Dallacasa, S. Torri, F. Mantovani

We present results and first epoch parsec-scale images from a monitoring program on five $γ$--ray loud blazars selected on the basis of their total flux density variability. We observed 0048$-$097, 0235+164, 0954+658, 1510$-$089 and 1749+096 with the Very Long Baseline Array simultaneously at 8.4 GHz and 22 GHz. Comparison between our high quality images and

T. Venturi, G. Giovannini, L. Feretti, W. D. Cotton

We report the most important results on the parsec-scale properties of a complete sample of radio galaxies carried out at radio frequencies with the Global VLBI array and with the VLBA. Relativistic parsec-scale jets are common both in FRI and FRII radio galaxies, and their orientation to the line of sight is in agreement with the expectations from the unifi

S. Piranomonte, M. Paolillo, G. Longo, S. Andreon

We present the composite luminosity function (hereafter LF) of galaxies for 80 Abell clusters studied in our survey of the Northern Hemisphere, using DPOSS data in the framework of the CRoNaRio collaboration. Our determination of the LF has been computed with very high accuracy thanks to the use of homogeneous data both for the clusters and the control field

A. A. Lutovinov, S. A. Grebenev, M. N. Pavlinsky, R. A. Sunyaev

We present a study of two X-ray bursters in the Galactic Center field with the ART-P telescope onboard GRANAT. During 1990-1992 approximately 100 X-ray bursts were detected from the Galactic Center field and most of them were identified with the two persistent sources, A1742-294 and SLX1744-299/300. The burst recurrence times were found to be ~2.4 and ~4.6 h

S. K. Ghosh, R. P. Verma

A new scheme of radiation transfer for understanding infrared spectra of H II regions, has been developed. This scheme considers non-equilibrium processes (e. g. transient heating of the very small grains, VSG; and the polycyclic aromatic hydrocarbon, PAH) also, in addition to the equilibrium thermal emission from normal dust grains (BG). The spherically sym

L. Feretti, G. Brunetti, G. Giovannini, F. Govoni

The number of diffuse radio halos in clusters of galaxies has grown in recent years, making it possible to derive statistical properties of these sources and of the hosting clusters. We show that diffuse sources are associated with X-ray luminous clusters which have undergone recent merger processes. The radio and X-ray structures are often similar, and corr

A. K. Inoue, H. Kamaya

We investigate the structure of the molecular cloud complexes (MCCs) as a group of several giant molecular clouds (GMCs) in the Galaxy. Then, we find that the mass-size relation which has been reported for the GMCs establishes well even for the very large MCCs whose size is about 1 kpc. Since the horizontal size of the MCCs is more than the thickness of the

Kohji Molikawa, Makoto Hattori

We show that an expected number ratio of radial arcs (gravitationally lensed images whose major axes lie in the radial direction of a cluster-lens potential) to tangential arcs (gravitationally lensed images whose major axes lie in the tangential direction) has strong dependence on the central density profile of galaxy clusters and has little dependence on o

T. Lebzelter, L. L. Kiss, K. H. Hinkle

NIR velocity variations are compared with simultaneous visual light curves for a sample of late-type semiregular variables (SRV). Precise radial velocity measurements are also presented for the SRV V450 Aql. Our aim is to investigate the nature of the irregular light changes found in these variables. Light and velocity variations are correlated in all stars

Mirek Giersz

A revision of Stod\{&#39;o}łkiewicz&#39;s Monte Carlo code is used to simulate evolution of large star clusters. A survey of the evolution of N-body systems influenced by the tidal field of a parent galaxy and by stellar evolution is presented. The results presented are in good agreement with theoretical expectations and the results of other methods (Fokker-

A. Ghez, M. Morris, E. E. Becklin, T. Kremenek

Recent measurements, of the velocities of stars near the center of the Milky Way have provided the strongest evidence for the presence of a supermassive black hole in a galaxy, but the observational uncertainties poorly constrain many of the properties of the black hole. Determining the accelerations of stars in their orbits around the center provides much m

J. Dyks, B. Rudak

We derive easy-to-handle approximations for the polar gap electric field due to inertial frame dragging as derived by Harding & Muslimov 1998. A simple formula valid for polar gap height comparable to the polar cap radius is presented.

Alexei Khavaev, Nicholas P. Warner

We consider the holographic dual of a general class of N=1* flows in which all three chiral multiplets have independent masses, and in which the corresponding Yang-Mills scalars can develop particular supersymmetry-preserving vevs. We also allow the gaugino to develop a vev. This leads to a six parameter subspace of the supergravity scalar action, and we sho

R. Machleidt

I will review recent progress in our understanding of the nuclear force. In the course of the 1990&#39;s, so-called high-precision, charge-dependent nucleon-nucleon potentials have been constructed which are, essentially, phenomenological models. These potentials are now commonly used as input for exact few-body calculations and microscopic nuclear many-body

Y. J. Kim, R. J. Birgeneau, F. C. Chou, M. Greven

We report a neutron scattering study on the tetragonal compound Sr_2Cu_3O_4Cl_2, which has two-dimensional (2D) interpenetrating Cu_I and Cu_{II} subsystems, each forming a S=1/2 square lattice quantum Heisenberg antiferromagnet (SLQHA). The mean-field ground state is degenerate, since the inter-subsystem interactions are geometrically frustrated. Magnetic n

Joaquim Gomis, Kiyoshi Kamimura, Toni Mateos

The Hamiltonian (gauge) symmetry generators of non-local (gauge) theories are presented. The construction is based on the d+1 dimensional space-time formulation of d dimensional non-local theories. The procedure is applied to U(1) space-time non-commutative gauge theory. In the Hamiltonian formalism the Hamiltonian and the gauge generator are constructed. Th

Everton M. C. Abreu, Alvaro de Souza Dutra

We have studied the theory of gauged chiral bosons and proposed a general theory, a master action, that encompasses different kinds of gauge field couplings in chiral bosonized theories with first-class chiral constraints. We have fused opposite chiral aspects of this master action using the soldering formalism and applied the final action to several well kn

D. Branch

In a recent paper Li et al. (2000) reported that 36 percent of 45 Type Ia supernovae (SNe Ia) discovered since 1997 in two volume-limited supernova searches were spectroscopically peculiar, and they suggested that because this peculiarity rate is higher than that reported for an earlier observational sample by Branch et al. (1993), it is now more likely that

A. DeBenedictis, A. Das

A general class of solutions is obtained which describe a spherically symmetric wormhole system. The presence of arbitrary functions allows one to describe infinitely many wormhole systems of this type. The source of the stress-energy supporting the structure consists of an anisotropic brown dwarf ``star&#39;&#39; which smoothly joins the vacuum and may poss

Dong Lai

The properties of matter are significantly modified by strong magnetic fields, $B>>2.35\times 10^9$ Gauss ($1 G =10^{-4} Tesla$), as are typically found on the surfaces of neutron stars. In such strong magnetic fields, the Coulomb force on an electron acts as a small perturbation compared to the magnetic force. The strong field condition can also be mimicked

A. A. Grib, Yu. V. Pavlov

Different models of the role of creation of superheavy particles in the early Friedmann Universe with their subsequent decay on light particles are investigated. The observable numbers of baryon and entropy are predicted. The possible role of superheavy particles in creation of cold dark matter is discussed.

Massimo Bianchi, Oliver DeWolfe, Daniel Z. Freedman, Krzysztof Pilch

We derive and solve a subset of the fluctuation equations about two domain wall solutions of D=5, N=8 gauged supergravity. One solution is dual to D=4, N=4 SYM theory perturbed by an N=1, SO(3)-invariant mass term and the other to a Coulomb branch deformation. In the first case we study all SO(3)-singlet fields. These are assembled into bulk multiplets dual

S. Kim, J. B. Kogut, M. -P. Lombardo

By adding a small, irrelevant four fermi interaction to the action of lattice Quantum Electrodynamics (QED), the theory can be simulated with massless quarks in a vacuum free of lattice monopoles. This allows an ab initio high precision, controlled study of the existence of &#34;textbook&#34; Quantum Electrodynamics with several species of fermions. The latt

R. Baier, A. H. Mueller, D. Schiff, D. T. Son

We describe how thermalization occurs in heavy ion collisions in the framework of perturbative QCD. When the saturation scale $Q_s$ is large compared to $Λ_{QCD}$, thermalization takes place during a time of order $α^{-13/5}Q_s^{-1}$ and the maximal temperature achieved is $α^{2/5}Q_s$.

A. Accardi, D. Treleani

The average number of minijets and the corresponding transverse energy produced in heavy ion collisions are evaluated by including explicitly semi-hard parton rescatterings in the dynamics of the interaction. At the LHC semi-hard rescatterings have a sizable effect on global characteristics of the typical inelastic event. An interesting feature is that the d

Kunihito Ioka

We present one possible mechanism for the giant flares of the Soft Gamma-Ray Repeaters (SGRs) within the framework of magnetar, i.e., superstrongly magnetized neutron star model, motivated by the positive period increase associated with the August 27 event from SGR 1900+14. From the second-order perturbation analysis of the equilibrium of the magnetic polytr

Andreas Honecker, Wolfram Brenig

We study a novel S=1/2 cluster chain Hamiltonian which has recently been proposed in the context of the charge ordered low-temperature phase of alpha&#39;-NaV2O5. We perform a detailed investigation of this model within a large range of parameters using perturbation theory and Lanczos diagonalization. Using model-specific local conservation laws and paramete

J. S. Winfield, S. Fortier, W. N. Catford, S. Pita

The 11Be(p,d)10Be reaction has been performed in inverse kinematics with a radioactive 11Be beam of E/A = 35.3 MeV. Angular distributions for the 0+ ground state, the 2+, 3.37 MeV state and the multiplet of states around 6 MeV in 10Be were measured at angles up to 16 deg CM by detecting the 10Be in a dispersion-matched spectrometer and the coincident deutero

A. L. Larsen, A. Nicolaidis

Using a world-sheet covariant formalism, we derive the equations of motion for second order perturbations of a generic macroscopic string, thus generalizing previous results for first order perturbations. We give the explicit results for the first and second order perturbations of a contracting near-circular string; these results are relevant for the underst

Kateryna Medvedyeva, Beom Jun Kim, Petter Minnhagen

It has been suggested [Pierson et al., Phys. Rev. B 60, 1309 (1999); Ammirata et al., Physica C 313, 225 (1999)] that for 2D superconductors there exists a phase transition with the dynamic critical exponent z\approx 5.6. We perform simulations for the 2D RSJ model and compare the results with the experimental data in Repaci et al. obtained for an ultrathin

Roberto Frezzotti, Martin Hasenbusch, Jochen Heitger, Karl Jansen

We report performance benchmarks for several algorithms that we have used to simulate the Schr&#34;odinger functional with two flavors of dynamical quarks. They include hybrid and polynomial hybrid Monte Carlo with preconditioning. An appendix describes a method to deal with autocorrelations for nonlinear functions of primary observables as they are met here

David H. Adams

It is proved that the fermionic topological charge of SU(N) lattice gauge fields on the 4-torus, given in terms of a spectral flow of the Hermitian Wilson--Dirac operator, or equivalently, as the index of the Overlap Dirac operator, reduces to the continuum topological charge in the classical continuum limit when the parameter $m_0$ is in the physical region

M. Laine, K. Rummukainen

Using a three-dimensional (3d) effective field theory and non-perturbative lattice simulations, we study the MSSM electroweak phase transition with two dynamical Higgs doublets. We first carry out a general analysis of spontaneous CP violation in 3d two Higgs doublet models, finding that this part of the parameter space is well separated from that correspond

Tetsuya Takaishi, Philippe de Forcrand

The standard hybrid Monte Carlo algorithm is known to simulate even flavors QCD only. Simulations of odd flavors QCD, however, can be also performed in the framework of the hybrid Monte Carlo algorithm where the inverse of the fermion matrix is approximated by a polynomial. In this exploratory study we perform three flavors QCD simulations. We make a compari

Kingman Cheung

The success of the Randall-Sundrum scenario relies on stabilization of the modulus field or the radion, which is the scalar field about the background geometry. The stabilization mechanism proposed by Goldberger and Wise has the consequence that this radion is lighter than the graviton Kaluza-Klein states so that the first particle to be discovered is the ra

C. S. Kim, Kang Young Lee, Jeonghyeon Song

The neutral Higgs pair production at the LHC is studied in the MSSM, the large extra dimensional (ADD) model and the Randall-Sundrum (RS) model, where the total cross section can be significantly enhanced compared to that in the SM. The $p_{_T}$, invariant mass and rapidity distributions of each model have been shown to be distinctive: The ADD model raises t

B. Meyer, David Vanderbilt

For the ferroelectric perovskite compounds BaTiO3 and PbTiO3, we have studied the effects of external electric fields on the structural properties of the (001) surfaces. The field-induced changes in the surface interlayer spacings and bucklings have been calculated using a first-principles ultrasoft-pseudopotential approach, and the change of the polarizatio

G. M. D&#39;Ariano, M. G. A. Paris, M. F. Sacchi

An effective maximum likelihood method is suggested to characterize the absorption/amplification properties of active optical media through homodyne detection.

G. M. D&#39;Ariano, M. F. Sacchi

We show that universally covariant cloning is not optimal for achieving joint measurements of noncommuting observables with minimum added noise. For such a purpose a cloning transformation that is covariant with respect to a restricted transformation group is needed.

Philippe Grangier, Frederic Grosshans

We discuss the criteria presently used for evaluating the efficiency of quantum teleportation schemes for continuous variables. It is argued that the fidelity criterion used so far has some severe drawbacks, and that a fidelity value larger than 2/3 is actually required for successful quantum teleportation. This value has never been reached experimentally so

Michele Irac-Astaud

New families of Molecular-Coherent-States are constructed by the Perelomov group-method. Each family is generated by a Molecular-Fundamental-State that depends on an arbitrary sequence of complex numbers cj. Two of these families were already obtained by D.Janssen and by J. A. Morales, E. Deumens and Y. Ohrn. The properties of these families are investigated

Kim J. Bostroem

A theoretical framework is presented allowing the treatment of quantum messages with components of variable length. To this aim a many-letter space, similiar to the Fock space, is constructed, generalizing the standard quantum information theory of block messages of fixed length. In the many-letter space a length operator can be defined measuring the length

Michail P. Rekalo, Jacques Arvieux, Egle Tomasi-Gustafsson

Parity violating asymmetry in inclusive scattering of longitudinally polarized electrons by unpolarized protons with $π^0$ or $π^+$ meson production, is calculated as a function of the momentum transfer squared $Q^2$ and the total energy $W$ of the $πN$-system. This asymmetry, which is induced by the interference of the one-photon exchange amplitude with the

A. M. Green, S. Wycech

The coupled eta-N, pi-N, gamma-N system is described by a K-matrix method. The parameters in this model are adjusted to get an optimal fit to pi-N --->pi- N$, pi-N --->eta-N$, gamma-N--->pi-N and gamma-N --->eta-N data in an energy range of about 100MeV or so each side of the eta threshold. The outcome is the appearance of two solutions one which has an eta-

Egle Tomasi-Gustafsson, Michail P. Rekalo

The purpose of this contribution is to give an outlook of recent results connected with deuteron physics, with electromagnetic and strong interacting probes at intermediate energy. Special attention will be devoted to polarization observables.

J. Pochodzalla, W. Trautmann

The measurement and interpretation of isotopic yield ratios in heavy ion reactions at intermediate and high energies are discussed and the usefulness of these observables for establishing equilibrium properties and for determining thermodynamic parameters is illustrated. The examples are mainly taken from work performed with lighter projectiles at intermedia

Stefan Keppeler

We determine the asymptotics of the two-point correlation function for quantum systems with half-integer spin which show chaotic behaviour in the classical limit using a method introduced by Bogomolny and Keating [Phys. Rev. Lett. 77 (1996) 1472-1475]. For time-reversal invariant systems we obtain the leading terms of the two-point correlation function of th

Jan Naudts, Maciej Kuna

We introduce new definitions of states and of representations of covariance systems. The GNS-construction is generalized to this context. It associates a representation with each state of the covariance system. Next, states are extended to states of an appropriate covariance algebra. Two applications are given. We describe a nonrelativistic quantum particle,

David Ruelle

Results of somewhat mysterious nature are known on the location of zeros of certain polynomials associated with statistical mechanics (Lee-Yang circle theorem) and also with graph counting. In an attempt at clarifying the situation we introduce and discuss here a natural class of polynomials. Let $P(z_1,...,z_m,w_1,...,w_n)$ be separately of degree 1 in each

Albert Tarantola, Klaus Mosegaard

While the axiomatic introduction of a probability distribution over a space is common, its use for making predictions, using physical theories and prior knowledge, suffers from a lack of formalization. We propose to introduce, in the space of all probability distributions, two operations, the OR and the AND operation, that bring to the space the necessary st

Thomas Treloar

We study the symplectic geometry of the moduli spaces $M_r=M_r(\s^3)$ of closed n-gons with fixed side-lengths in the 3-sphere. We prove that these moduli spaces have symplectic structures obtained by reduction of the fusion product of $n$ conjugacy classes in SU(2), denoted $C_r^n$, by the diagonal conjugation action of SU(2). Here $C_r^n$ is a quasi-Hamilt

Naichung Conan Leung

To each del Pezzo surface (resp. ruled surface, ruled surface with a section), we describe a natural Lie algebra bundle of type E_n (resp. D_n, A_n) over it. Using lines and rulings on any such surface, we describe various representation bundles corresponding to fundamental representations of the corresponding Lie algebra. When we specify a geometric structu

Andreas Gathmann

Let X be a smooth complex projective variety, and let Y in X be a smooth very ample hypersurface such that -K_Y is nef. Using the technique of relative Gromov-Witten invariants, we give a new short and geometric proof of (a version of) the &#34;mirror formula&#34;, i.e. we show that the generating function of the genus zero 1-point Gromov-Witten invariants o

Robin Chapman

We introduce three-variable analogues of the theta series of Borwein and Borwein. We prove various identities involving these theta series including a generalization of the cubic identity of Borwein and Borwein.

Maria Gorelik

The category of representations with a strongly typical central character of a basic classical Lie superalgebra is proven to be equivalent to the category of representations of its even part corresponding to an appropriate central character. For a Lie superalgebra $osp(1,2l)$ the category of representations with a &#34;generic&#34; weakly atypical central ch

Piotr M. Hajac, Rainer Matthes, Wojciech Szymanski

We define the $C^*$-algebra of quantum real projective space $\R P_q^2$, classify its irreducible representations and compute its $K$-theory. We also show that the $q$-disc of Klimek-Lesniewski can be obtained as a non-Galois $\Z_2$-quotient of the equator Podleś quantum sphere. On the way, we provide the Cartesian coordinates for all Podleś quantum spheres

M. R. Razvan

In this paper, we generalize Conley&#39;s fundamental theorem of dynamical systems in Conley index theory. We also conclude the existence of regular index filtration for every Morse decomposition.

P. G. Casazza, C. L. Garcia, W. B. Johnson

Following Davie&#39;s example of a Banach space failing the approximation property [D], we show how to construct a Banach space E which is asymptotically Hilbertian and fails the approximation property. Moreover, the space E is shown to be a subspace of a space with an unconditional basis which is ``almost&#39;&#39; a weak Hilbert space and which can be writ

C. D. Fosco, V. E. R. Lemes, L. E. Oxman, S. P. Sorella

We show that the functional bosonization procedure can be generalized in such a way that, to any field theory with a conserved Abelian charge in (2+1) dimensions, there corresponds a dual Abelian gauge field theory. The properties of this mapping and of the dual theory are discussed in detail, presenting different explicit examples. In particular, the meanin

Ali H. Chamseddine

A deformation of Einstein Gravity is constructed based on gauging the noncommutative ISO(3,1) group using the Seiberg-Witten map. The transformation of the star product under diffeomorphism is given, and the action is determined to second order in the deformation parameter.

Kei-Ichi Kondo

We show that the QCD vacuum (without dynamical quarks) is a dual superconductor at least in the low-energy region in the sense that monopole condensation does really occur. In fact, we derive the dual Ginzburg-Landau theory (i.e., dual Abelian Higgs model) directly from the SU(2) Yang-Mills theory by adopting the maximal Abelian gauge. The dual superconducto

A. Abbas

It is commonly believed that $π^0 \to 2 γ$ decay shows that there are three colours in Quantum Chromodynamics (QCD). It is shown here that this is not correct. When correct colour dependent charges of the quarks are considered then it is shown that this decay does not make any statement about the number of colours in QCD.

Harry J. Lipkin

Simple experimental tests are proposed which can clarify the origin for the anomalously high $η&#39;$ appearance in charmless strange final states in $B$ decays and can investigate the the nature of SU(3) symmetry-breaking in weak heavy flavor decays.

H. Arthur Weldon

The asymptotic behavior as t\to\infty and r\to\infty of the hard-thermal-loop propagator D^{μν}(t,r) is computed in the Coulomb gauge. The asymptotic falloff is always a power law though generally different in the deep time-like and space-like regions. The contributions of quasiparticle poles and Landau branch cuts are computed. The most difficult calculatio

M. Vanderhaeghen, D. Drechsel, M. Gorchtein, A. Metz

We report on a dispersion relation formalism for the virtual Compton scattering (VCS) reaction on the proton, which for the first time allows a dispersive evaluation of 4 generalized polarizabilities. The dispersion formalism provides a new tool to analyze VCS experiments above pion threshold, thus increasing the sensitivity to the generalized polarizabiliti

Carl E. Carlson

We consider decays of the lowest-lying radially excited baryons. Assuming a single-quark decay approximation, and negligible configuration mixing, we make model-independent predictions for the partial decay widths to final states with a single meson. Masses of unobserved states are predicted using an old mass formula rederived using large-$N_c$ QCD. The mome

Radovan Dermisek

We calculate the proton lifetime in an SO(10) supersymmetric grand unified theory [SUSY GUT] with U(2) family symmetry. This model fits the low energy data, including the recent data for neutrino oscillations. We discuss the predictions of this model for the proton lifetime in light of recent SuperKamiokande results which significantly constrain the SUSY par

A. Donnachie, J. Gravelis, G. Shaw

A two-gluon-exchange model incorporating perturbative and non-perturbative effects is presented for rho electroproduction which provides an excellent description of all current data. This is then used to calculate the contribution from the rho to deeply virtual Compton scattering via the vector-meson-dominance transition rho -> gamma. This is found to be suf

Robert Botet, Marek Ploszajczak

Universal scaling laws of fluctuations (the $Δ$-scaling laws) can be derived for equilibrium and off-equilibrium systems when combined with the finite-size scaling analysis. In any system in which the second-order critical behavior can be identified, the relation between order parameter, criticality and scaling law of fluctuations has been established and th

Sh. Matsumoto, M. Yoshimura

Time evolution of tunneling in thermal medium is examined using the real-time semiclassical formalism previously developed. Effect of anharmonic terms in the potential well is shown to give a new mechanism of resonance enhanced tunneling. If the friction from environment is small enough, this mechanism may give a very large enhancement for the tunneling rate

T. Huang

In terms of an effective Lagrangian we investigate the possibilities of probing anomalous top quark couplings, $t \bar{t} H$, $γt \bar{t}$, $Z t \bar{t}$ and $tWb$ at the future linear colliders. It is found that probing anomalous top quark couplings, $t \bar{t} H$, $γt \bar{t}$, $Z t \bar{t}$ and $tWb$ at the future linear colliders. It is found that at a l

Belal E. Baaquie, Y S Seng

We present the main results of our microcanonical simulation of the Wess Zumino Witten action functional. This action, being highly non-trivial and capable of exhibiting many different phase transitions, is chosen to be representative of general complex actions. We verify the applicability of microcanonical simulation by successfully obtaining two of the man

D. Cinabro

The latest results from the CLEO collaboration are summarized. An update on the status of the upgraded CLEO III detector is also included.

S. Chen, CLEO Collaboration

Using a sample of 9.7 million B meson pairs collected with the CLEO detector, we study B decays to the chi_c1 and chi_c2 charmonia states, which are reconstructed via their radiative decays to J/psi. We first measure the branching fraction for inclusive chi_c1 production in B decays to be Br(B->chi_c1 X)=(4.14+-0.31+-0.40)*10^-3, where the first uncertainty

Thorsten Wengler

The hadronic interactions of the photon are studied in terms of new measurements of the total hadronic cross section and di-jet production in photon-photon collisions at LEP2.

M. Mohseni, H. R. Sepangi

The motion of a classical spinning test particle in the field of a weak plane gravitational wave is studied. It is found that the characteristic dimensions of the particle&#39;s orbit is sensitive to the ratio of the spin to the mass of the particle. The results are compared with the corresponding motion of a particle without spin.

Christof Monz

In this paper, an application of automated theorem proving techniques to computational semantics is considered. In order to compute the presuppositions of a natural language discourse, several inference tasks arise. Instead of treating these inferences independently of each other, we show how integrating techniques from formal approaches to context into dedu