April 1997 arXiv papers — page 3

Goutam Tripathy, Mustansir Barma

We study the effect of quenched disorder on nonequilibrium systems of interacting particles, specifically, driven diffusive lattice gases with spatially disordered jump rates. The exact steady-state measure is found for a class of models evolving by drop-push dynamics, allowing several physical quantities to be calculated. Dynamical correlations are studied

Sutapa Mukherji, Somendra M. Bhattacharjee

In a city of right moving and upmoving cars with hardcore constraint, traffic jam occurs in the form of bands. We show how the bands are destroyed by a small number of strictly left moving cars yielding a deadlock phase with a rough edge of left cars. We also show that the probability of waiting time at a signal for a particular tagged car has a power law de

Kirk Korista, Gary Ferland, Jack Baldwin

Recent observations of quasars, Mrk 335 and the HST quasar composite spectrum, have indicated that many of them have remarkably soft ionizing continua (fnu ~ nu^-2.0, 13.6 eV -- 100 eV). We point out that the number of E > 54.4 eV photons is insufficient to create the observed strengths of the He II emission lines. While the numbers of photons which energize

Dimitri Polyakov

We review our recent discussion of fivebrane central terms that appear in the space-time superalgebra in D=10 provided that the space-time supercharges are taken in non-canonical pictures. We correct the mistake contained in the original version of the earlier paper hep-th/9703008 which suggested that the naive picture-changing of the superalgebra could give

R. Leidl, A. Drewitz, H. W. Diehl

We study the influence of the surface orientation on the wetting behavior of bcc binary alloys, using a semi-infinite lattice model equivalent to a nearest-neighbor Ising antiferromagnet in an external field. The salient feature of the model is the generation of an ``effective'' ordering surface field for symmetry-breaking surface orientations like (

S. Dalley, B. van de Sande

We investigate in some detail consequences of the effective colour-dielectric formulation of lattice gauge theory using the light-cone Hamiltonian formalism with a transverse lattice. As a quantitative test of this approach, we have performed extensive analytic and numerical calculations for 2+1-dimensional pure gauge theory in the large N limit. Because of

Helio V. Fagundes, Evelise Gausmann

We briefly summarize the idea of cosmological models with compact, flat spatial sections. It has been suggested that, because of the COBE satellite's maps of the microwave background, such models cannot be small in the sense of Ellis, and hence are no longer interesting. Here we use Lehoucq et al.'s method of cosmic crystallography to show that these

D. Müller

The conformal algebra provides powerful constraints, which guarantee that renormalized conformally covariant operators exist in the hypothetical conformal limit of the theory, where the $β$-function vanishes. Thus, in this limit also the conformally covariant operator product expansion on the light cone holds true. This operator product expansion has predict

M. B. Tsang, P. Danielewicz

Arrhenius-type plots for multifragmentation process, defined as the transverse energy dependence of the single-fragment emission-probability, -ln(p_{b}) vs 1/sqrt(E_{t}), have been studied by examining the relationship of the parameters p_{b} and E_{t} to the intermediate-mass fragment multiplicity <n>. The linearity of these plots reflects the correlation o

E. Abdalla

The main principles of two-dimensional quantum field theories, in particular two-dimensional QCD and gravity are reviewed. We study non-perturbative aspects of these theories which make them particularly valuable for testing ideas of four-dimensional quantum field theory. The dynamics of confinement and theta vacuum are explained by using the non-perturbativ

R. Argurio, F. Englert, L. Houart, P. Windey

We relate, in 10 and 11 dimensional supergravities, configurations of intersecting closed branes with vanishing binding energy to configurations where one of the branes opens and has its boundaries attached to the other. These boundaries are charged with respect to fields living on the closed brane. The latter hosts electric and magnetic charges stemming fro

M. V. Chizhov

The anomalous value of the tensor form factor in the kaon decay K -> pi e nu and the destructive interference in pion decay pi -> e nu gamma can be simultaneously described by admixture of a tensor interaction in the standard V-A one. It is shown that the same tensor interaction can describe recent HERA data at very large Q^2.

Alejandro Cabo, Eloy Ayon

Physical arguments related with the existence of black hole solutions having a non trapping interior are discussed. Massive scalar fields interacting with gravity are considered. Interior asymptotic solutions showing a scalar field approaching a constant value at the horizon are given. It is argued that the coupled Einstein-Klein-Gordon equations can be sati

W. D. Heiss, R. G. Nazmitdinov

A model for quantum dots is proposed, in which the motion of a few electrons in a three-dimensional harmonic oscillator potential under the influence of a homogeneous magnetic field of arbitrary direction is studied. The spectrum and the wave functions are obtained by solving the classical problem. The ground state of the Fermi-system is obtained by minimizi

B. Czerny, T. Bulik, M. Sikora, O. Vilhu

The accurate position determination of GRB 970228 by the Beppo/SAX Satellite led to the discovery of a fading X-ray and optical counterparts of the burst. About a month after the GRB event the proper motion of the ejecta was detected and the extended optical source has faded below the Keck detection level. We analyze these observations in the framework of th

Ue-Li Pen

An algorithm for simulating self-gravitating cosmological astrophysical fluids is presented. The advantages include a large dynamic range, parallelizability, high resolution per grid element and fast execution speed. The code is based on a finite volume flux conservative Total-Variation-Diminishing (TVD) scheme for the shock capturing hydro, and an iterative

Carlo Graziani, Donald Q. Lamb, Raphael Slawinski

We present a new method of transient point source deconvolution for coded-aperture X-Ray detectors. Our method is based upon the calculation of the likelihood function and its interpretation as a probability density for the transient source position by an application of Bayes&#39; Theorem. The method obtains point estimates of source positions by finding the

Gary T. Horowitz

I review the recent progress in providing a statistical foundation for black hole thermodynamics. In the context of string theory, one can now identify and count quantum states associated with black holes. One can also compute the analog of Hawking radiation (in a certain low energy regime) in a manifestly unitary way. Both extremal and nonextremal black hol

M. J. Duff, H. Lu, C. N. Pope

We present four-dimensional M-theory vacua with N>0 supersymmetry which, from the perspective of perturbative Type IIA string theory, have N=0. Such vacua can appear when the compactifying 7-manifold is a U(1) fibration. The missing superpartners are Dirichlet 0-branes. Someone unable to detect Ramond-Ramond charge would thus conclude that these worlds have

I. Dolgachev, C. Werner

We prove that a recent construction of a numerical Godeaux surface due to P. Craighero and R. Gattazzo is simply connected, and show how to realize their construction as a double plane. By proving that the surface contains no (-2)-curves, we obtain that this is the first example of a simply connected surface with vanishing geometric genus and ample canonical

Shamit Kachru, Eva Silverstein

We provide evidence that some four-dimensional N=1 string vacua with different numbers of generations are connected through phase transitions. The transitions involve going through a point in moduli space where there is a nontrivial fixed point governing the low energy field theory. In an M-theory description, the examples involve wrapped 5-branes leaving on

ZEUS Collaboration

The reaction gamma p -> J/Psi p has been studied in ep interactions using the ZEUS detector at HERA. The cross section for elastic J/Psi photoproduction has been measured as a function of the photon-proton centre of mass energy W in the range 40 < W < 140 GeV at a median photon virtuality Q^2 of 5*10^{-5} GeV^2. The photoproduction cross section, sigma_{gamm

A. Nersessian

A twistor model is proposed for the free relativistic anyon. The Hamiltonian reduction of this model by the action of the spin generator leads to the minimal covariant model; whereas that by the action of spin and mass generators, to the anyon model with free phase space that is a cotangent bundle of the Lobachevsky plane with twisted symplectic structure. Q

H. Fujisaki

The thermofield dynamics of the D = 10 heterotic thermal string theory is described in proper reference to the thermal duality symmetry as well as the thermal stability of modular invariance in association with the global phase structure of the D = 10 heterotic thermal string ensemble.

Andrzej Z. Gorski, Pawel O. Mazur

We suggest in this Letter that the Bekenstein-Hawking black hole entropy accounts for the degrees of freedom which are excited at low temperatures only and hence it leads to the negative specific heat. Taking into account the physical degrees of freedom which are excited at high temperatures, the existence of which we postulate, we compute the total specific

Thang T. Q. Le

The integrality of the Kontsevich integral and perturbative invariants is discussed. We show that the denominator of the degree $n$ part of the Kontsevich integral of any knot or link is a divisor of $(2!3!... n!)^4(n+1)!$. We also show that the denominator of of the degree $n$ part of the universal perturbative invariant of homology 3-spheres is not divisib

Klaus Dietrich, Krzysztof Pomorski

We investigate the shell structure of bubble nuclei in simple phenomenological shell models and study their binding energy as a function of the radii and of the number of neutron and protons using Strutinsky&#39;s method. Shell effects come about, on the one hand, by the high degeneracy of levels with large angular momentum and, on the other, by the big ener

Frank Wagner

Groups definable in simple theories retain the chain conditions and decomposition properties known from stable groups, up to commensurability. In the small case, if a generic type of G is not foreign to some type q, there is a q-internal quotient. In the supersimple case, the Berline-Lascar decomposition works. One-based simple groups are finite-by-abelian-b

M. S. Baouendi, P. Ebenfelt, Linda Preiss Rothschild

Let $M$ be a real analytic hypersurface in $\bC^N$ which is finitely nondegenerate, a notion that can be viewed as a generalization of Levi nondegenerate, at $p_0\in M$. We show that if $M&#39;$ is another such hypersurface and $p&#39;_0\in M&#39;$, then the set of germs at $p_0$ of biholomorphisms $H$ with $H(M)\subset M&#39;$ and $H(p_0)=p&#39;_0$, equippe

R. Kallosh, J. Kumar

We examine the supersymmetry of classical D-brane and M-brane configurations and explain the dependence of Killing spinors on coordinates. We find that one half supersymmetry is broken in the bulk and that supersymmetry near the D-brane horizon is restored for $p\leq 3$, for solutions in the stringy frame, but only for $p=3$ in the10d canonical frame. We stu

P. L. Natti, A. F. R. de Toledo Piza

We study the small oscillations regime (RPA approximation) of the time-dependent mean-field equations, obtained in a previous work, which describe the time evolution of one-body dynamical variables of a uniform Chiral Gross-Neveu system. In this approximation we obtain an analytical solution for the time evolution of the one-body dynamical variables. The two

Freydoon Mansouri

It is pointed out that if we allow for the possibility of a multilayered universe, it is possible to maintain exact supersymmetry and arrange, in principle, for the vanishing of the cosmological constant. Superpartner(s) of a known particle will then be associated with the other layers of such a universe. A concrete model realizing this scenario is exhibited

F. Lizzi, G. Mangano, G. Miele, G. Sparano

In a recent paper we pointed out the presence of extra fermionic degrees of freedom in a chiral gauge theory based on Connes Noncommutative Geometry. Here we propose a mechanism which provides a high mass to these mirror states, so that they decouple from low energy physics.

Khazret S. Nirov

Gauge-invariant systems of a general form with higher order derivatives of gauge parameters are investigated within the framework of the BFV formalism. Higher order terms of the BRST charge and BRST-invariant Hamiltonian are obtained. It is shown that the identification rules for Lagrangian and Hamiltonian ghost variables depend on the choice of the extensio

K. N. Ilinski, G. V. Kalinin, A. S. Stepanenko

In the paper we begin a description of functional methods of quantum field theory for systems of interacting q-particles. These particles obey exotic statistics and are the q-generalization of the colored particles which appear in many problems of condensed matter physics, magnetism and quantum optics. Motivated by the general ideas of standard field theory

Euy Soo Na, Barry R. Holstein

We show that recent calculations of ΔI=3/2 effects in nonleptonic hyperon decay induced by m_d-m_u\neq 0 are subject to significant model dependence.

Changhao Jin, Emmanuel A. Paschos

We show how radiative QCD corrections calculated in terms of quarks can be incorporated at the hadron level in inclusive semileptonic B-meson decays. The bound state effects are described by a momentum distribution function of the $b$ quark. The summation over the final states and the averaging over the momentum distribution of the decaying quark render the

P. Desgrolard, A. I. Lengyel, E. S. Martynov

Alternatives for describing the nonlinear behavior of the first diffraction cone in differential $pp$ and $\bar pp$ elastic cross-section are investigated. High quality fits to the data are presented. We show that the presence in the Pomeron amplitude of two terms with different $t$ dependences is strongly suggested by the data, hinting at a non-factorizable

Hung Hsiang Liu

We propose a formalism for calculating the event cross-section of parton interactions. In this formalism, we use the light-front bound-state wave function to expand scattering initial state. This leads to an expression of the cross-section in terms of square of wave functions which can be used to define the parton distribution functions. The probability inte

D0 Collaboration, S. Abachi

We present a measurement of the ttbar production cross section in ppbar collisions at root(s) = 1.8TeV by the D0 experiment at the Fermilab Tevatron. The measurement is based on data from an integrated luminosity of approximately 125 pb^-1 accumulated during the 1992-1996 collider run. We observe 39 ttbar candidate events in the dilepton and lepton+jets deca

CLEO Collaboration, D. M. Asner et al

Using the CLEO-II data set we have searched for the Cabibbo-suppressed decays B^0 -> D^{(*)+} D^{(*)-}. For the decay B^0 -> D^{*+} D^{*-}, we observe one candidate signal event, with an expected background of 0.022 +/- 0.011 events. This yield corresponds to a branching fraction of Br(B^0 -> D^{*+} D^{*-}) = (5.3^{+7.1}_{-3.7}(stat) +/- 1.0(syst)) x 10^{-4}

David Brown

Black hole entropy is derived from a sum over boundary states. The boundary states are labeled by energy and momentum surface densities, and parametrized by the boundary metric. The sum over state labels is expressed as a functional integral with measure determined by the density of states. The sum over metrics is expressed as a functional integral with meas

Naresh Dadhich, K. Narayan

The third law of black hole dynamics states that the surface gravity (temperature) of black hole cannot be reduced to zero in finite sequence of physical interactions. We argue that the same is true when surface gravity is replaced by gravitational charge. We demonstrate that the prescribed window for infalling energy and radiation pinches off as extremality

K. D. Elworthy, Xue-Mei Li, Steven Rosenberg

We relate the positivity of the curvature term in the Weitzenbock formula for the Laplacian on p-forms on a complete manifold to the existence of bounded and $L^2$ harmonic forms. In the case where the manifold is the universal cover of a compact manifold, we obtain topological and geometric information about the compact manifold. For example, we show that a

G. Burdet, M. Perrin

The geometrical structures (in the sense of E. Cartan) are analyzed which underlie the gravitational radiation phenomenon. Among the results are : - the introduction of the adapted frame bundle to a congruence of isotropic hypersurfaces in a Lorentzian manifold, - the description of the reduced frame bundle which admits a unique radiation connection induced

R. Montgomery, M. Shapiro, A. Stolin

The group of real 4 by 4 upper triangular matrices with 1s on the diagonal has a left-invariant subRiemannian (or Carnot-Caratheodory) structure whose underlying distribution corresponds to the superdiagonal. We prove that the associated subRiemannian geodesic flow is not completely integrable. This provides the first example of a Carnot group (graded nilpot

Richard Montgomery

An Engel structure is a maximally non-integrable field of two-planes tangent to a four-manifold. Any two such structures are locally diffeomorphic. We investigate the space of global deformations of canonical Engel structures arising out of contact three-manifolds. The main tool is Cartan&#39;s method of prolongation and deprolongation which lets us pass bac

Andrew D. Rutenberg, Wojtek J. Zakrzewski, Martin Zapotocky

Strong dynamical scaling violations exist in quenched two-dimensional systems with vector O(3) order parameters. These systems support non-singular topologically stable configurations (skyrmions). By tuning the stability of isolated skyrmions to expand or shrink, we find dramatic differences in the dynamical multiscaling spectrum of decaying moments $< |ρ|^n

Giorgio Parisi

In this note we study the approach to equilibrium of a chain of anharmonic oscillators. We find indications that a sufficiently large system always relaxes to the usual equilibrium distribution. There is no sign of an ergodicity threshold. The time however to arrive to equilibrium diverges when $g \to 0$, $g$ being the anharmonicity.

German Sierra, Miguel A. Martin-Delgado

Using a recursive method we construct dimer and nondimer variational ansatzs of the ground state for the two-legged ladder, and compute the number of dimer coverings, the energy density and the spin correlation functions. The number of dimer coverings are given by the Fibonacci numbers for the dimer-RVB state and their generalization for the nondimer ones. O

R. M. Cavalcanti, E. S. Fraga, C. A. A. de Carvalho

We study the problem of an electron in two dimensions in the presence of a magnetic vortex with a step-like profile. Dependending on the values of the effective mass and gyromagnetic factor of the electron, it may be trapped by the vortex. The bound state spectrum is obtained numerically, and some limiting cases are treated analytically.

H. Rosner, H. Eschrig, R. Hayn, S. -L. Drechsler

Sr_2CuO_3 and Ca_2CuO_3 are considered to be model systems of strongly anisotropic, spin-1/2 Heisenberg antiferromagnets. We report on the basis of a band-structure analysis within the local density approximation and on the basis of available experimental data a careful analysis of model parameters for extended Hubbard and Heisenberg models. Both insulating

K. Held, M. Ulmke, N. Bl&#34;umer, D. Vollhardt

The microscopic origin of metamagnetism and metamagnetic transitions in strongly anisotropic antiferromagnets is investigated within a quantum mechanical theory of correlated electrons. To this end the Hubbard model with staggered magnetization m_st along an easy axis e in a magnetic field H || e is studied both analytically and numerically within the dynami

Kengo Ichiki, Hisao Hayakawa

Systematic simulations are carried out based on the model of fluidized beds proposed by the present authors [K.Ichiki and H.Hayakawa, Phys. Rev. E vol.52, 658 (1995)]. From our simulation, we confirm that fluidization is a continuous transition. We also confirm the existence of two types of fluidized phases, the channeling phase and the bubbling phase. We fi

Elke Teich, Beate Firzlaff, John A. Bateman

The paper deals with the problem of text generation and planning approaches making only limited formally specifiable contact with accounts of grammar. We propose an enhancement of a systemically-based generation architecture for German (the KOMET system) by aspects of Kunze&#39;s theory of semantic emphasis. Doing this, we gain more control over both concept

Kemal Oflazer, Gokhan Tur

We present a constraint-based morphological disambiguation system in which individual constraints vote on matching morphological parses, and disambiguation of all the tokens in a sentence is performed at the end by selecting parses that receive the highest votes. This constraint application paradigm makes the outcome of the disambiguation independent of the

John A. Bateman

This paper discusses the use of `ontologies&#39; in Natural Language Processing. It classifies various kinds of ontologies that have been employed in NLP and discusses various benefits and problems with those designs. Particular focus is then placed on experiences gained in the use of the Upper Model, a linguistically-motivated `ontology&#39; originally desi

Veniamin Berezinsky, Alexander Vilenkin

Cosmic necklaces are hybrid topological defects consisting of monopoles and strings, with two strings attached to each monopole. We argue that the cosmological evolution of necklaces may significantly differ from that of cosmic strings. The typical velocity of necklaces can be much smaller than the speed of light, and the characteristic scale of the network

W. J. Henney, S. J. Arthur

Many low-mass stars in the Orion nebula are associated with very compact (~= 1 arcsec) emission knots, known variously as proplyds, PIGs or LV knots. Some of these knots are teardrop-shaped, with ``tails&#39;&#39; pointing away from the massive star Theta 1 Ori C, which is the principal exciting star of the nebula. We discuss models of such knots, which invo

John N. Bahcall

This article summarizes the process by which astronomers and astrophysicists reached a consensus view as to what are the highest priority scientific projects for the decade of the 1990s. I also review the remarkable success of these recommendations.

Jean-Michel Alimi, Arturo Serna

In a previous paper (Serna & Alimi 1996), we have pointed out the existence of some particular scalar-tensor gravity theories able to relax the nucleosynthesis constraint on the cosmic baryonic density. In this paper, we present an exhaustive study of primordial nucleosynthesis in the framework of such theories taking into account the currently adopted obser

Evalyn Gates, Geza Gyuk, Michael S. Turner

By means of extensive galactic modeling we study the implications of the more than 100 microlensing events that have now been observed for the composition of the dark halo of the Galaxy. Based on the currently published data, including the 2nd year MACHO results, the halo MACHO fraction is less than 60% in most models and the likelihood function for the halo

Anne M Green, Andrew R Liddle

We re-examine the constraints on the density perturbation spectrum, including its spectral index $n$, from the production of primordial black holes. The standard cosmology, where the Universe is radiation dominated from the end of inflation up until the recent past, was studied by Carr, Gilbert and Lidsey; we correct two errors in their derivation and find a

Dominik J. Schwarz, C. Schmid, P. Widerin

We investigate the effect of the cosmological QCD transition on the evolution of primordial density perturbations. If the phase transition is first order, the sound speed vanishes during the transition and density perturbations fall freely. The Harrison-Zel&#39;dovich spectrum of density fluctuations develops large peaks on scales below the Hubble radius at

Fred Hamann

This paper provides a general reference for deriving the ionizations and metal abundances for absorption-line clouds in photoionization equilibrium with a QSO spectrum. The results include a quantitative assessment of the theoretical uncertainties and firm lower limits on the metallicities when no ionization constraints are available. The calculations applie

Daniel J. Eisenstein, Emory F. Bunn

A recent paper (Nodland and Ralston, PRL 78, 3043, astro-ph/9704196) claims to have detected evidence for birefringence in the propagation of radio waves across cosmological distances. In order to assess the statistical significance of their results, the authors analyze simulated data sets, finding a stronger correlation in the real data than in the simulati

V. Barger, Chung Kao

We calculate the relic density ($Ω_{χ^0_1} h^2$) of neutralino dark matter in supergravity models with radiative electroweak symmetry breaking, for values of the Higgs sector parameter $\tanβ\equiv v_2/v_1$ between the two infrared fixed points of the top quark Yukawa coupling, $\tanβ\simeq 1.8$ and $\tanβ\simeq 56$. For $\tanβ\alt 10$, the CP-odd Higgs pseu

Ivar Martin, Philip Phillips

We analyse here the role electrons on Anderson-U impurities play in superconductivity in a metal alloy. We find that phonon coupling at impurities counteracts the traditional effects which dominate T_c suppression in the non-magnetic limit. In some cases, we findt hat non-magnetic impurities can enhance T_c. In the Kondo limit, a Fermi liquid analysis reveal

E. Gaztanaga, C. M. Baugh

We produce mock angular catalogues from simulations with different initial power spectra to test methods that recover measures of clustering in three dimensions, such as the power spectrum, variance and higher order cumulants. We find that the statistical properties derived from the angular mock catalogues are in good agreement with the intrinsic clustering

Tsafrir Kolatt

(Abridged) This paper introduces the formalism which connects between rotation measure ($\RM$) measurements for extragalactic sources and the cosmological magnetic field power spectrum. It is shown that the amplitude and shape of the cosmological magnetic field power spectrum can be constrained by using a few hundred radio sources, for which Faraday $\RM$s a

E. Abdalla, R. Banerjee

We compute the quark-antiquark potential in three dimensional massive Quantum Electrodynamics. The result indicates that screening prevails for large quark masses, contrary to the classical expectations. The classical result is reproduced for small separation of the quarks.

Helmut Haberzettl

Based on an effective field theory of hadrons in which quantum chromodynamics is assumed to provide the necessary bare cutoff functions, a gauge-invariant theory of pion photoproduction with fully dressed nucleons is developed. The formalism provides consistent dynamical descriptions of pi-N --> pi-N scattering and Gamma-N --> pi-N production mechanisms in t

A. Feinstein, Ruth Lazkoz, M. A. Vazquez-Mozo

We present a general algorithm which permits to construct solutions in string cosmology for heterotic and type-IIB superstrings in four dimensions. Using a chain of transformations applied in sequence: conformal, T-duality and SL(2,R) rotations, along with the usual generating techniques associated to Geroch transformations in Einstein frame, we obtain solut

O. J. P. Eboli, M. C. Gonzalez-Garcia, S. F. Novaes

We obtain constraints on possible anomalous interactions of the top quark with the electroweak vector bosons arising from the precision measurements at the Z pole. In the framework of $SU(2)_L \otimes U(1)_Y$ chiral Lagrangians, we examine all effective CP-conserving operators of dimension five which induce fermionic currents involving the top quark. We cons

S. Tsujimaru, K. Yamawaki

We study the zero mode and the spontaneous symmetry breaking on the light front (LF). We use the discretized light-cone quantization (DLCQ) of Maskawa-Yamawaki to treat the zero mode in a clean separation from all other modes. It is then shown that the Nambu-Goldstone (NG) phase can be realized on the trivial LF vacuum only when an explicit symmetry-breaking

Riccardo Barbieri, Alessandro Strumia

CP violation in hadronic B-decays is studied in a definite and well motivated framework of flavour physics and supersymmetry. Possible deviations from the standard model both in mixing and in decay amplitudes are discussed. An attempt is made to describe an experimental strategy for looking at these deviations and for measuring the relevant parameters.

Bruce A. Bassett

The gravitational wave equations form a parametric resonance system during oscillatory reheating after inflation, when cast in terms of the electric and magnetic parts of the Weyl tensor. This is in direct analogy with preheating. For chaotic inflation with a quadratic potential, this analogy is exact. The resulting amplification of the gravitational wave sp

L. Baulieu, H. Kanno, I. M. Singer

We build nearly topological quantum field theories in various dimensions. We give special attention to the case of 8 dimensions for which we first consider theories depending only on Yang-Mills fields. Two classes of gauge functions exist which correspond to the choices of two different holonomy groups in SO(8), namely SU(4) and Spin(7). The choice of SU(4)

Priyamvada Natarajan, Steinn Sigurdsson

Sunyaev-Zeldovich decrements in the temperature of the Cosmic Microwave Background (CMB) are produced by Thomson scattering of the CMB photons by the confined hot electrons in the Intra-Cluster Medium encountered along the line-of-sight. In this paper, we propose an alternate physical process that can produce detectable thermal and kinematic Sunyaev-Zeldovic

Masahito Hayashi

The optimization of measurement for n samples of pure sates are studied. The error of the optimal measurement for n samples is asymptotically compared with the one of the maximum likelihood estimators from n data given by the optimal measurement for one sample.

Hou Defu, U. Heinz

We derive a set of relations among the thermal components of the 3-point function and its spectral representations at finite temperature in the real-time formalism. We then use these to explicitly calculate the 3-point spectral densities for $ϕ^3_6$ theory and relate the result to the case of hot QCD.

Masahito Hayashi

In this paper it was proved that the quantum relative entropy $D(σ\| ρ)$ can be asymptotically attained by Kullback Leibler divergences of probabilities given by a certain sequence of POVMs. The sequence of POVMs depends on $ρ$, but is independent of the choice of $σ$.

F. Hamann, T. Barlow, R. D. Cohen, V. Junkkarinen

We discuss two aspects of the ionization and abundances in QSO intrinsic absorbers. First, we use the high-ionization doublet Ne VIII 770,780 to test the relationship between the UV line absorbers and the ``warm&#39;&#39; absorbers detected in soft X-rays. In one well-measured QSO with intrinsic z_a ~ z_e lines, UM 675, we estimate that the UV absorber has a

Eric M. Rains

It is reasonable to expect the theory of quantum codes to be simplified in the case of codes of minimum distance 2; thus, it makes sense to examine such codes in the hopes that techniques that prove effective there will generalize. With this in mind, we present a number of results on codes of minimum distance 2. We first compute the linear programming bound

Eric M. Rains

The weight enumerators (quant-ph/9610040) of a quantum code are quite powerful tools for exploring its structure. As the weight enumerators are quadratic invariants of the code, this suggests the consideration of higher-degree polynomial invariants. We show that the space of degree k invariants of a code of length n is spanned by a set of basic invariants in

H. T. Koelink, J. Van der Jeugt

Using realisations of the positive discrete series representations of the Lie algebra su(1,1) in terms of Meixner-Pollaczek polynomials, the action of su(1,1) on Poisson kernels of these polynomials is considered. In the tensor product of two such representations, two sets of eigenfunctions of a certain operator can be considered and they are shown to be rel

W. C. Haxton

The opening of the meson factories twenty years ago provided nuclear physics with new beams, higher momentum transfers, and new opportunities for precision measurements. The resulting changes in nuclear physics were substantial, altering not only the range of physics issues identified with the field but also the manner and size of the collaborations that do

W. C. Haxton

I discuss in qualitative terms the implications of the recent measurement by C. S. Wood et al. of the hyperfine dependence of atomic parity violation in 133Cs. The derived anapole moment constrains the strength of hadronic parity violation.

W. R. Gibbs, Li Ai, W. B. Kaufmann

This paper contains the results of an analysis of recent low-energy pion-nucleon scattering experiments. Obtained are phase shifts, the pion-nucleon coupling constant and an estimate of the Sigma term.

G. Faeldt, C. Wilkin

The cross section and analyzing power of the pol{p}p -> pn pi+ reaction near threshold are estimated in terms of data obtained from the pol{p}p -> d pi+ and pp -> pp pi0 reactions. A simple final state interaction theory is developed which depends weakly upon the form of the pion-production operator and includes some Coulomb corrections. Within the uncertain

V. V. Sokolov, V. G. Zelevinsky

Simple states, such as isobaric analog states or giant resonances, embedded into continuum are typical for mesoscopic many-body quantum systems. Due to the coupling to compound states in the same energy range, a simple mode acquires a damping width (&#34;internal&#34; dynamics). When studied experimentally with the aid of various reactions, such states revea

D. Pelte, FOPI collaboration

Charged pions from Ni + Ni reactions at 1.05, 1.45 and 1.93 AGeV are measured with the FOPI detector. The mean $π^{\pm}$ multiplicities per mean number of participants increase with beam energy, in accordance with earlier studies of the Ar + KCl and La + La systems. The pion kinetic energy spectra have concave shape and are fitted by the superposition of two

Andre Lukas, Burt A. Ovrut

We study U-duality symmetries of toroidally compactified M theory from the membrane worldvolume point of view. This is done taking the most general set of bosonic background fields into account. Upon restriction to pure moduli backgrounds, we are able to find the correct U-duality groups and moduli coset parameterizations for dimensions D>6 as symmetries of

E. Dudas, C. Grojean

We investigate compactifications of M-theory from $11\to 5\to 4$ dimensions and discuss geometrical properties of 4-d moduli fields related to the structure of 5-d theory. We study supersymmetry breaking by compactification of the fifth dimension and find that an universal superpotential is generated for the axion-dilaton superfield $S$. The resulting theory

Sukanta Bose

We briefly review the status of the ``graceful exit&#39;&#39; problem in superstring cosmology and present a possible resolution. It is shown that there exists a solution to this problem in two-dimensional dilaton gravity provided quantum corrections are incorporated. This is similar to the recently proposed solution of Rey. However, unlike in his case, in o

Jose M. Isidro, Avijit Mukherjee, Joao P. Nunes, Howard J. Schnitzer

A new method to obtain the Picard-Fuchs equations of effective, N=2 supersymmetric gauge theories with massive matter hypermultiplets in the fundamental representation is presented. It generalises a previously described method to derive the Picard-Fuchs equations of both pure super Yang-Mills and supersymmetric gauge theories with massless matter hypermultip

Marika Taylor-Robinson

We calculate the absorption rates of fixed scalars by near extremal five dimensional black holes carrying general one-brane and five-brane charges by semi-classical and D-brane methods. We find that the absorption cross-sections do not in general agree for either fixed scalar and we discuss possible explanations of the discrepancy.

Ofer Aharony, Amihay Hanany

We analyze various brane configurations corresponding to field theories in three, four and five dimensions. We find brane configurations which correspond to three dimensional N=2 and four dimensional N=1 supersymmetric QCD theories with quartic superpotentials, in which what appear to be ``hidden parameters&#39;&#39; play an important role. We discuss the co

John Ellis, N. E. Mavromatos, D. V. Nanopoulos

Within the general framework of Liouville string theory, we construct a model for quantum D-brane fluctuations in the space-time background through which light closed-string states propagate. The model is based on monopole and vortex defects on the world sheet, which have been discussed previously in a treatment of 1+1-dimensional black-hole fluctuations in

J. Cruz, J. M. Izquierdo, D. J. Navarro, J. Navarro-Salas

It is shown that the 1+1-dimensional matter-coupled Jackiw-Teitelboim model and the model with an exponential potential can be converted by means of appropriate canonical transformations into a bosonic string theory propagating on a flat target space with an indefinite signature. This makes it possible to consistently quantize these models in the functional