April 1996 arXiv papers — page 4

Carlos Frontera, Eduard Vives, Teresa Castán, Antoni Planes

A Monte Carlo study of the late time growth of $L1_2$ ordered domains on a fcc $A_3B$ binary alloy is presented. The energy of the alloy has been modeled by a nearest neighbor interaction Ising hamiltonian. The system exhibits a fourfold degenerated ground-state and two kinds of interfaces separating ordered domains: flat and curved antiphase boundaries. Two

Vladimir I. Fal'ko, K. B. Efetov

We study correlations of the amplitudes of wave functions of a chaotic system at large distances. For this purpose, a joint distribution function of the amplitudes at two distant points in a sample is calculated analytically using the supersymmetry technique. The result shows that, although in the limit of the orthogonal and unitary symmetry classes the corr

Adriana G. Moreira, Ronald Dickman

We study critical spreading dynamics in the two-dimensional contact process (CP) with quenched disorder in the form of random dilution. In the pure model, spreading from a single particle at the critical point $λ_c$ is characterized by the critical exponents of directed percolation: in $2+1$ dimensions, $δ= 0.46$, $η= 0.214$, and $z = 1.13$. Disorder causes

Miriaam Butt, Christian Fortman, Christian Rohrer

This paper focuses on two disparate aspects of German syntax from the perspective of parallel grammar development. As part of a cooperative project, we present an innovative approach to auxiliaries and multiple genitive NPs in German. The LFG-based implementation presented here avoids unnessary structural complexity in the representation of auxiliaries by ch

George Anton Kiraz

This paper presents a generalised two-level implementation which can handle linear and non-linear morphological operations. An algorithm for the interpretation of multi-tape two-level rules is described. In addition, a number of issues which arise when developing non-linear grammars are discussed with examples from Syriac.

Geunbae Lee, Jong-Hyeok Lee, JinHee Yoo

Most of the post-processing methods for character recognition rely on contextual information of character and word-fragment levels. However, due to linguistic characteristics of Korean, such low-level information alone is not sufficient for high-quality character-recognition applications, and we need much higher-level contextual information to improve the re

Michael D. Gregg, Robert H. Becker, Richard L. White, David J. Helfand

The FIRST Radio Survey provides a new resource for constructing a large quasar sample. With source positions accurate to better than 1\arcsec\ and a point source sensitivity limit of 1 mJy, it reaches 50 times deeper than previous radio catalogs. We report here on the results of the pilot phase for a FIRST Bright Quasar Survey (FBQS). Based on matching the r

Petri Vaisanen

Several models which have been constructed to explain the faint galaxy excess in observed number counts are used to predict the intensity of the extragalactic background light (EBL). Special attention is given to irregular and dwarf galaxies, which seem to be more common in the universe than once thought, and to low surface brightness galaxies (LSB), which c

Duncan A. Forbes, Marijn Franx, Garth D. Illingworth, C. M. Carollo

Here we present HST WFPC2 imaging of 14 kinematically--distinct core ellipticals to examine their globular cluster systems. In particular, we probe the galaxy central regions, for which we might expect to see the strongest signatures of some formation and destruction processes. These data substantially increase the number of extragalactic globular cluster sy

Rachel A. Pildis, August E. Evrard, Joel N. Bregman

We analyze compact groups of galaxies appearing in a galaxy formation simulation dominated by cold dark matter (omega_0=1, omega_{baryon}=0.1). The simulation uses an N-body code to model the behavior of the non-baryonic matter and smoothed particle hydrodynamics to model the baryons. One run includes gas dynamics alone, and the other incorporates star forma

Ari Buchalter, Marc Kamionkowski

The parallax effect in ground-based microlensing (ML) observations consists of a distortion to the standard ML light curve arising from the Earth's orbital motion. In most cases, the resolution in current ML surveys is not accurate enough to observe this effect, but parallax could conceivably be detected with frequent followup observations of ML events i

Adam Riess, William Press, Robert Kirshner

We present an empirical method that uses multicolor light curve shapes (MLCS) to estimate the luminosity, distance, and total line-of-sight extinction of Type Ia supernovae (SN Ia). The empirical correlation between the MLCS and the luminosity is derived from a ``training set'' of nine SN Ia light curves with independent distance and reddening estima

D. Schade, R. G. Carlberg, H. K. C. Yee, O. Lopez-Cruz

Two-dimensional surface photometry is presented for a sample of 351 late-type galaxies with $0.12 < z < 0.65$. These objects are drawn from the Canadian Network for Observational Cosmology (CNOC) cluster survey and are either spectroscopically confirmed members of clusters at $z=0.23$ (64 galaxies), $0.43$ (45), and $0.55$ (36) or field galaxies with similar

Gerd Müller

The automorphism group ${\rm Aut}\: X$ of a weighted homogeneous normal surface singularity $X$ has a maximal reductive algebraic subgroup $G$ which contains every reductive algebraic subgroup of ${\rm Aut}\: X$ up to conjugation. In all cases except the cyclic quotient singularities the connected component $G_1$ of the unit equals ${\Bbb C}^*$. The induced

Eduard Looijenga, Valery L. Lunts

Each choice of a Kähler class on a compact complex manifold defines an action of the Lie algebra $\slt$ on its total complex cohomology. If a nonempty set of such Kähler classes is given, then we prove that the corresponding $\slt$-copies generate a semisimple Lie algebra. We investigate the formal properties of the resulting representation and we work thing

F. Gabbiani, E. Gabrielli, A. Masiero, L. Silvestrini

We analyze the full set of constraints on gluino- and photino-mediated SUSY contributions to FCNC and CP violating phenomena. We use the mass insertion method, hence providing a model-independent parameterization which can be readily applied in testing extensions of the MSSM. In addition to clarifying controversial points in the literature, we provide a more

Austin Pickering, Peter West

We calculate the Kahlerian and the lowest order non-Kahlerian contributions to the one loop effective superpotential using super-Feynman graphs in the massless Wess-Zumino Model, the massive Wess-Zumino Model and N=1, U(1) gauge theory. We also calculate the Kahlerian term in Yang-Mills Theory for a general gauge group. Using this latter result we find the o

H. J. Schulz

Static and dynamical properties of weakly coupled antiferromagnetic spin chains are treated using a mean--field approximation for the interchain coupling and exact results for the resulting effective one--dimensional problem. Results for staggered magnetization, Néel temperature and spin wave excitations are in agreement with experiments on $\rm KCuF_3$. The

I. A. B. Strachan

A deformed differential calculus is developed based on an associative star-product. In two dimensions the Hamiltonian vector fields model the algebra of pseudo-differential operator, as used in the theory of integrable systems. Thus one obtains a geometric description of the operators. A dual theory is also possible, based on a deformation of differential fo

Sergei V. Ketov

The most general four-dimensional non-linear sigma-model, having the second-order derivatives only and interacting with a background metric and an antisymmetric tensor field, is constructed. Despite its apparent non-renormalizability, just imposing the one-loop UV-finiteness conditions determines the unique model, which may be finite to all orders of the qua

A. Y. Potekhin, D. G. Yakovlev

Practical expressions are derived for a rapid and accurate evaluation of electric and thermal conductivities and thermopower of degenerate relativistic electrons along quantizing magnetic fields in outer neutron star crusts. The electron Coulomb scattering on ions is considered in liquid matter, and on high-temperature phonons or charged impurities in solid

Charles H. Bennett, David P. DiVincenzo, John A. Smolin, William K. Wootters

Entanglement purification protocols (EPP) and quantum error-correcting codes (QECC) provide two ways of protecting quantum states from interaction with the environment. In an EPP, perfectly entangled pure states are extracted, with some yield D, from a mixed state M shared by two parties; with a QECC, an arbi- trary quantum state $|ξ\rangle$ can be transmitt

Itzhak Bars

A global superalgebra with 32 supercharges and all possible central extensions is studied in order to extract some general properties of duality and hidden dimensions in a theory that treats $p$-branes democratically. The maximal number of dimensions is 12, with signature (10,2), containing one space and one time dimensions that are hidden from the point of

Hong Liu, Tanmay Vachaspati

We find the spectrum of magnetic monopoles produced in the symmetry breaking SU(5) to [SU(3)\times SU(2)\times U(1)&#39;]/Z_6 by constructing classical bound states of the fundamental monopoles. The spectrum of monopoles is found to correspond to the spectrum of one family of standard model fermions and hence, is a starting point for constructing the dual st

Richard J. Hughes, Daniel F. V. James, Emanuel H. Knill, Raymond Laflamme

Using simple physical arguments we investigate the capabilities of a quantum computer based on cold trapped ions. From the limitations imposed on such a device by spontaneous decay, laser phase coherence, ion heating and other sources of error, we derive a bound between the number of laser interactions and the number of ions that may be used. The largest num

Bindu A. Bambah, G. S. Agarwal

We introduce and study the properties of a class of coherent states for the group SU(1,1) X SU(1,1) and derive explicit expressions for these using the Clebsch-Gordan algebra for the SU(1,1) group. We restrict ourselves to the discrete series representations of SU(1,1). These are the generalization of the `Barut Girardello&#39; coherent states to the Kroneck

Scott Pratt, Kevin Haglin

The degree to which a nucleus can act as a source for coherent pion pairs is investigated for intermediate-energy heavy-ion collisions. Creation through both isovector and isoscalar channels is considered. Two experimental signals are proposed for evidence of two-pion coherent production, two-pion enhancement and the focusing of outgoing pions along the beam

J. S. Al-Khalili, J. A. Tostevin

We re-examine the matter radii of diffuse halo nuclei, as deduced from reaction cross section measurements at high energy. Careful consideration is given to the intrinsic few-body structure of these projectiles and the adiabatic nature of the projectile-target interaction. Using $^{11}$Li, $^{11}$Be and $^{8}$B as examples we show that data require significa

Oe. Elgaroey, L. Engvik, M. Hjorth-Jensen, E. Osnes

$^{3}P_{2}$ pairing in neutron matter is investigated using the Bonn potential models. We find pairing energy gaps in pure neutron matter comparable to the results of previous investigators when the attractive tensor coupling is included. However, taking into account that in a neutron star we have matter at $β$ equilibrium, we find that the $^{3}P_{2}$-$^{3}

Robert Osserman, Min Ru

We give an estimate of the Gauss curvature for minimal surfaces in ${\mathbb R}^m$ whose Gauss map omits more than $m(m+1)/2$ hyperplanes in ${\mathbb P}^{m-1}({\mathbb C})$.

Valeri V. Dvoeglazov

It has long been claimed that antisymmetric tensor field of the second rank is longitudinal after quantization. Such a situation is quite unacceptable from a viewpoint of the Correspondence Principle. On the basis of the Lagrangian formalism we calculate the Pauli-Lyuban&#39;sky vector of relativistic spin for this field. Even at the classical level it can b

W. Kalau, M. Walze

The purpose of this article is to apply the concept of the spectral triple, the starting point for the analysis of noncommutative spaces in the sense of A.~Connes, to the case where the algebra $\cA$ contains both bosonic and fermionic degrees of freedom. The operator $\cD$ of the spectral triple under consideration is the square root of the Dirac operator u

A. A. Andrianov, F. Cannata, J. -P. Dedonder, M. V. Ioffe

Representations of the quantum q-oscillator algebra are studied with particular attention to local Hamiltonian representations of the Schroedinger type. In contrast to the standard harmonic oscillators such systems exhibit a continuous spectrum. The general scheme of realization of the q-oscillator algebra on the space of wave functions for a one-dimensional

Markus J. Pflaum

In this work we give a deformation theoretical approach to the problem of quantization. First the notion of a deformation of a noncommutative ringed space over a commutative locally ringed space is introduced within a language coming from Algebraic Geometry and Complex Analysis. Then we define what a Dirac quantization of a commutative ringed space with a Po

Yu. A. Sitenko

The method of self-adjoint extensions is employed to determine the vacuum quantum numbers induced by a singular static magnetic vortex in $2+1$-dimensional spinor electrodynamics. The results obtained are gauge-invariant and, for certain values of the extension parameter, both periodic in the value of the vortex flux and possessing definite parity with respe

Ralph Blumenhagen, Andreas Wisskirchen

We use an exactly solvable (0,2) supersymmetric conformal field theory with gauge group SO(10) to investigate the superpotential of the corresponding classical string vacuum. We provide evidence that the rational point lies in the Landau-Ginzburg phase of the linear sigma-model and calculate exactly all three- and four-point functions of the gauge singlets.

Jan Sladkowski

Short introduction to exotic differential structures on manifolds is given. The possible physical context of this mathematical curiosity is discussed. The topic is very interesting although speculative.

S. J. Brodsky, B. -Q. Ma

Although the distributions of sea quarks and antiquarks generated by leading-twist QCD evolution through gluon splitting $g \rightarrow \bar q q$ are necessarily CP symmetric, the distributions of nonvalence quarks and antiquarks which are intrinsic to the nucleon&#39;s bound state wavefunction need not be identical. In this paper we investigate the sea quar

C. Ford, C. Wiesendanger

To resum large logarithms in multi-scale problems a generalization of $\MS$ is introduced allowing for as many renormalization scales as there are generic scales in the problem. In the new \lq\lq minimal multi-scale subtraction scheme&#39;&#39; standard perturbative boundary conditions become applicable. However, the multi-loop beta functions depend on the v

S. J. Brodsky

In this talk, I review the use of the light-cone Fock expansion as a tractable and consistent description of relativistic many-body systems and bound states in quantum field theory and as a frame-independent representation of the physics of the QCD parton model. Nonperturbative methods for computing the spectrum and LC wavefunctions are briefly discussed. Th

J. Matias

The formalism of the matching conditions between transverse connected Green functions is extended to include the two next to leading corrections, namely the two-loop $M_{H}^{2}$ and the one-loop $1/M_{H}^{2}$ contributions to the coefficients of the electroweak chiral lagrangian which are relevant to the LEP1 physics: $a_{0}$, ${\hat a}_{1}$ and ${\hat a}_{8

Lincoln Wolfenstein

The symmetry between quarks and leptons suggests that neutrinos should have mass. As embodied in the grand unified theory SO(10) this yields masses that can only be detected by neutrino oscillations. Such oscillations could be very important for supernova physics. Present observations of solar neutrinos when combined with standard solar model calculations im

M. Dasgupta, B. R. Webber

We study the power corrections (infrared renormalon contributions) to the coefficient functions for non-singlet deep inelastic structure functions due to gluon vacuum polarization insertions in one-loop graphs. Remarkably, for all the structure functions $F_1$, $F_2$, $F_3$ and $g_1$, there are only two such contributions, corresponding to $1/Q^2$ and $1/Q^4

S. Aid

At the electron-proton collider HERA the inclusive $D^{*\pm}$ meson photoproduction cross section has been measured with the H1 detector in two different, but partly overlapping, kinematical regions. For the first, where $<W_{γp}> \approx 200$ GeV and $Q^2 < 0.01 \gev^2$, the result is $σ(γp \to c \bar{c} X) = (13.2 \pm 2.2 ^{+2.1}_{-1.7} ^{+9.9}_{-4.8}) μb$

C. Wiesendanger

The conventional role of spacetime geometry in the description of gravity is pointed out. Global Poincar$\acute{\mbox{e}}$ symmetry as an inner symmetry of field theories defined on a fixed Minkowski spacetime is discussed. Its extension to local {\bf P\/} gauge symmetry and the corresponding {\bf P\/} gauge fields are introduced. Their minimal coupling to m

Ruy Exel

Given a Fell bundle $\B$, over a discrete group $Γ$, we construct its reduced cross sectional algebra $C^*_r(\B)$, in analogy with the reduced crossed products defined for C*-dynamical systems. When the reduced and full cross sectional algebras of $\B$ are isomorphic, we say that the bundle is amenable. We then formulate an approximation property which we pr

Man Chun Leung

We study a second order ordinary differential equation corresponding to rotationally symmetric $p$-harmonic maps. We show unique continuation and Liouville&#39;s type theorems for positive solutions. We discuss the existence of bounded positive entire solutions. Asymptotic properties of the positive solutions are investigated.

Vijay S. Pande, Alexander Yu. Grosberg, Chris Joerg, Toyoichi Tanaka

It is widely held that the Random Energy Model (REM) describes the freezing transition of a variety of types of heteropolymers. We demonstrate that the hallmark property of REM, statistical independence of the energies of states over disorder, is violated in different ways for models commonly employed in heteropolymer freezing studies. The implications for p

Patrick A. Lee, Eduardo R. Mucciolo, Henrik Smith

We study the dephasing of fermions interacting with a fluctuating transverse gauge field. The divergence of the imaginary part of the fermion self energy at finite temperatures is shown to result from a breakdown of Fermi&#39;s golden rule due to a faster than exponential decay in time. The strong dephasing affects experiments where phase coherence is probed

S. V. Meshkov, D. Foerster

We consider a simplified model of the magnetic structure of the two-dimensional compound $CaV_4O_9$ in terms of interacting square plaquettes of spins with two distinct antiferromagnetic exchange constants. We analyze the competition between two types of singlet ground states and the Neel ordered one in terms of respectively, numerical cluster expansion and

T. Fukui, N. Kawakami

The exact solution of the spin chain model with $1/r^2$ exchange is found for twisted boundary conditions. The spectrum thus obtained can be reproduced by the asymptotic Bethe ansatz. The spectral flow of each eigenstate is determined exactly as a function of the twist angle. We find that the period $4π$ for the ground state nicely fits in with the notion of

Walt Detmar Meurers, Guido Minnen

We investigate the use of a technique developed in the constraint programming community called constraint propagation to automatically make a HPSG theory more specific at those places where linguistically motivated underspecification would lead to inefficient processing. We discuss two concrete HPSG examples showing how off-line constraint propagation helps

Pierre Boullier

In this paper we present a new parsing algorithm for linear indexed grammars (LIGs) in the same spirit as the one described in (Vijay-Shanker and Weir, 1993) for tree adjoining grammars. For a LIG $L$ and an input string $x$ of length $n$, we build a non ambiguous context-free grammar whose sentences are all (and exclusively) valid derivation sequences in $L

L. D. Carlos, A. L. L. Videira

Representing polyether-salt systems by chains of interacting coordination shells, defined by the cation and by its nearest ligands, we derive the interaction potential between closest shells -- the inter-shells potential -- in terms of two-electron polarization effects. Values are presented for monovalent-based crystalline poly(ethylene oxide), PEO, electrol

Charles C. Steidel, Mauro Giavalisco, Mark Dickinson, Kurt L. Adelberger

We report on the initial results of a spectroscopic investigation of galaxies in the Hubble Deep Field which exhibit spectral discontinuities between the F450W and F300W passbands, indicative of the presence of the Lyman continuum break in the redshift range 2.4 < z < 3.4. We have employed color selection criteria similar to those we have used for selecting

S. Ghigna, S. A. Bonometto, J. Retzlaff, S. Gottloeber

We use the void probability function to compare the redshift--space galaxy distribution in the Perseus--Pisces survey with artificial samples from N-body simulations of standard cold dark matter (CDM) and broken scale invariance (BSI) models. Galaxies are identified as residing in peaks of the evolved density field in such a way as to reproduce both the obse

L. Van Waerbeke, Y. Mellier, P. Schneider, B. Fort

A new method for measuring the shear induced by gravitational light deflection is proposed. It is based on analyzing the anisotropy induced in the auto-correlation function (ACF) of the extragalactic background light which is produced by very faint distant galaxies. The ACF can be measured `locally&#39;, and its anisotropy is caused by the tidal gravitationa

R. van Dijk, K. Bennett, H. Bloemen, W. Collmar

We present an analysis of COMPTEL observations made between November 1991 and May 1994 of 2CG 135+01, a bright gamma-ray source located near the Galactic plane. At energies above 1 MeV, an excess consistent with the position of 2CG 135+01 is detected in the sum of the observations, at flux levels which are a factor of 10-100 below those published in the past

E. Egami, F. Iwamuro, T. Maihara, S. Oya

Using the OH-airglow suppressor spectrograph at the University of Hawaii 2.2m telescope and the CGS4 spectrometer at the United Kingdom Infrared Telescope, we have found exceptionally large Balmer decrements in two unusual high-z QSOs, Hawaii 167 (z=2.36, Ha/Hb = 13) and Q0059-2735 (z=1.59, Ha/Hb = 7.6), the latter being a so-called low-ionization broad abso

E. Romero-Colmenero, G. Branduardi-Raymont, F. J. Carrera, L. R. Jones

We analyse the ROSAT PSPC spectrum of 19 X-ray selected Narrow Emission Line Galaxies (NELGs) discovered during the optical identification of sources in the ROSAT UK Deep Survey. Their properties are compared to those of broad line Active Galactic Nuclei (AGN) in the same sample. Counts in three spectral bands have been extracted for all the sources, and hav

S. Frink, B. Fuchs, S. Roeser, R. Wielen

We present rotation curves of the Galaxy based on the space-velocities of 197 OB stars and 144 classical cepheids, respectively, which range over a galactocentric distance interval of about 6 to 12 kpc. No significant differences between these rotation curves and rotation curves based solely on radial velocities assuming circular rotation are found. We deriv

P. Jablonka, P. Martin, N. Arimoto

Optical integrated spectra of bulges have been obtained for 28 spiral galaxies. By applying an appropriate aperture size for each galaxy, the unavoidable contamination of disk starlight has been carefully minimized and set to $\sim$ 1/7 of the total stellar light. The sample covers a wide range in bulge luminosity and morphology. The Mg$_2$ index shows a tig

Jean Schneider

The discovery of an increasing number of Jupiter-like planets in orbit around other stars (or extra-solar planets) is a promising first step toward the search for Life in the Universe. We review all aspects of the question: - definition of Life - definition and characterization of the `habitable zone&#39; around a star - overview of detection methods of plan

Finn Larsen, Frank Wilczek

We discuss why classical hair is desirable for the description of black holes, and show that it arises generically in a wide class of field theories involving extra dimensions. We develop the canonical formalism for theories with the matter content that arises in string theory. General covariance and duality are used to determine the form of surface terms. W

Ya. M. Blanter, A. D. Mirlin

Correlations of eigenfunctions, $\langle|ψ_k(r_1)|^2|ψ_l(r_2)|^2\rangle$, in a disordered system are investigated. We derive general formulae expressing these correlation functions in terms of the supermatrix sigma-model. In particular case of weak localization regime we find that the correlations of the same eigenfunction are proportional to $g^{-1}$ for la

Andreas Knaebchen, Yehoshua Levinson, Ora Entin-Wohlman

The propagation of a surface acoustic wave (SAW) on GaAs/AlGaAs heterostructures is studied in the case where the two-dimensional electron gas (2DEG) is subject to a strong magnetic field and a smooth random potential with correlation length Lambda and amplitude Delta. The electron wave functions are described in a quasiclassical picture using results of per

Behnam Farid

We propose a self-consistent scheme for the determination of the ground-state (GS) properties of interacting electrons in a magnetic field, and of systems whose GS&#39;s time-reversal-symmetry (TRS) is spontaneously broken. It is based on a newly-developed many-body perturbation theory that is valid, irrespective of the strength of correlation, provided the

L. Mankiewicz, T. Weigl

It has been suggested that parton distributions in coordinate space, so called Ioffe-time distributions, provide a more natural object for non-perturbative methods compared to the usual momentum distributions. In this paper we argue that the shape of experimentally determined Ioffe-time distributions of quarks in a nucleon target clearly indicates separation

Subir Sachdev, N. Read

We discuss the quantum paramagnetic phases of Heisenberg antiferromagnets on the 1/5-depleted square lattice found in $Ca V_4 O_9$. The possible phases of the quantum dimer model on this lattice are obtained by a mapping to a quantum-mechanical height model. In addition to the ``decoupled&#39;&#39; phases found earlier, we find a possible intermediate spin-P

M. Beccaria, B. Alles, F. Farchioni

The coherent state path integral formulation of certain many particle systems allows for their non perturbative study by the techniques of lattice field theory. In this paper we exploit this strategy by simulating the explicit example of the diffusion controlled reaction $A+A\to 0$. Our results are consistent with some renormalization group-based predictions

Eric G. Gimon, Clifford V. Johnson

We study string theory propagating on R^6 times K3 by constructing orientifolds of Type IIB string theory compactified on the T^4/Z_N orbifold limits of the K3 surface. This generalises the Z_2 case studied previously. The orientifold models studied may be divided into two broad categories, sometimes related by T-duality. Models in category A require either

V. V. Flambaum, D. W. Murray

A radial magnetic field can induce a time invariance violating electric dipole moment (EDM) in quantum systems. The EDMs of the Tl, Cs, Xe and Hg atoms and the neutron that are produced by such a field are estimated. The contributions of such a field to the constants, $χ$ of the T,P-odd interactions $χ_e {\bf N} \cdot {\bf s}/s$ and $χ_N {\bf N} \cdot {\bf I

Sen-Ben Liao, Michael Strickland

We investigate the critical behavior of the lambda phi^4 theory defined on S^1 x R^d having two finite length scales beta, the circumference of S^1, and k^{-1}, the blocking scale introduced by the renormalization group transformation. By numerically solving the coupled differential RG equations for the finite-temperature blocked potential U_{beta,k}(Phi) an

K. Behnia, H. Aubin, L. Taillefer, R. Gagnon

The thermal conductivity of Zn-doped YBCO crystals was studied at low temperature (0.15 < T < 0.8 K) for different concentrations of Zn impurities. A small amount of Zn induces a dramatic decrease in the non-linear component of the low-temperature thermal conductivity. Moreover, the magnitude of the linear component (obtained by extrapolating the data to T=0

W. X. Ma, B. Fuchssteiner

An integrable theory is developed for the perturbation equations engendered from small disturbances of solutions. It includes various integrable properties of the perturbation equations: hereditary recursion operators, master symmetries, linear representations (Lax and zero curvature representations) and Hamiltonian structures etc. and provides us a method t

Benjamin Schumacher

This paper addresses some general questions of quantum information theory arising from the transmission of quantum entanglement through (possibly noisy) quantum channels. A pure entangled state is prepared of a pair of systems $R$ and $Q$, after which $Q$ is subjected to a dynamical evolution given by the superoperator $\superop^{Q}$. Two interesting quantit

Benjamin Schumacher, M. A. Nielsen

This paper investigates properties of noisy quantum information channels. We define a new quantity called {\em coherent information} which measures the amount of quantum information conveyed in the noisy channel. This quantity can never be increased by quantum information processing, and it yields a simple necessary and sufficient condition for the existence

E. Biham, B Huttner, T Mor

Quantum correlations between two particles show non-classical properties which can be used for providing secure transmission of information. We present a quantum cryptographic system, in which users store particles in quantum memories kept in a transmission center. Correlations between the particles stored by two users are created upon request by projecting

T. Opatrny, D. -G. Welsch, W. Vogel

A new method is described for determining the quantum state of correlated multimode radiation by interfering the modes and measuring the statistics of the superimposed fields in four-port balanced homodyne detection. The full information on the $N$-mode quantum state is obtained by controlling both the relative amplitudes and the phases of the modes, which s

C. Beck, D. Mahboub, R. Nouicer, T. Matsuse

The fully energy-damped yields from the $^{35}$Cl+$^{12}$C reaction have been systematically investigated using particle-particle coincidence techniques at a $^{35}$Cl bombarding energy of $\sim$ 8 MeV/nucleon. The fragment-fragment correlation data show that the majority of events arises from a binary-decay process with rather large numbers of secondary lig

Michael Jakobson, Sheldon Newhouse

We prove the existence of Sinai-Ruelle-Bowen measures for a class of $C^2$ self-mappings of a rectangle with unbounded derivatives. The results can be regarded as a generalization of a well-known one dimensional Folklore Theorem on the existence of absolutely continuous invariant measures. In an earlier paper analogous results were stated and the proofs were

Peter E. Haagensen

Target space duality transformations are considered for bosonic sigma models and strings away from RG fixed points. A set of consistency conditions are derived, and are seen to be nontrivially satisfied at one-loop order for arbitrary running metric, antisymmetric tensor and dilaton backgrounds. Such conditions are sufficiently stringent to enable an indepen

Arne L. Larsen, Minos Axenides

We consider general properties of charged circular cosmic strings in a general family of world-sheet string models. We then specialize to a model recently proposed by Carter and Peter. This model was shown to give a good description of the features of the superconducting cosmic strings originally discovered by Witten. We derive an explicit expression for the

B. S. Acharya

It is argued that $M$-theory compactified on {\it any} of Joyce&#39;s $Spin(7)$ holonomy 8-manifolds are dual to compactifications of heterotic string theory on Joyce 7-manifolds of $G_2$ holonomy.

J. Beckers, N. Debergh, C. Quesne

A superposition of bosons and generalized deformed parafermions corresponding to an arbitrary paraquantization order $p$ is considered to provide deformations of parasupersymmetric quantum mechanics. New families of parasupersymmetric Hamiltonians are constructed in connection with two examples of su(2) nonlinear deformations such as introduced by Polychrona

E. Cremmer, J. -L. Gervais, J. Schnittger

In a previous paper, we proposed a construction of $U_q(sl(2))$ quantum group symmetry generators for 2d gravity, where we took the chiral vertex operators of the theory to be the quantum group covariant ones established in earlier works. The basic idea was that the covariant fields in the spin $1/2$ representation themselves can be viewed as generators, as

Min-Ho Lee, Jae Kwan Kim

By using the brick wall method we calculate the thermodynamic potential of the complex scalar field in a charged Kerr black hole. Using it we show that in the Hartle-Hawking state the leading term of the entropy is proportional to $\frac{ A _H}{ε^2}$, which becomes divergent as the system approaches the black hole horizon. The origin of the divergence is tha

D. J. Broadhurst

A generating function is given for the number, $E(l,k)$, of irreducible $k$-fold Euler sums, with all possible alternations of sign, and exponents summing to $l$. Its form is remarkably simple: $\sum_n E(k+2n,k) x^n = \sum_{d|k}μ(d) (1-x^d)^{-k/d}/k$, where $μ$ is the Möbius function. Equivalently, the size of the search space in which $k$-fold Euler sums of

Martina Brisudova

We present a QCD bound-state calculation based on a renormalization group-improved light-front Hamiltonian formalism. The QCD Hamiltonian is determined to second order in the coupling, and it includes two-body confining interactions. We make a momentum expansion, obtaining an equal-time-like Schrodinger equation. This is solved for quark-antiquark constituen

L. Magnea, E. Maina

We present complete results for the $O(α_s)$ corrections to the production of a heavy quark pair plus a hard photon, in $e^+ e^-$ annihilation, including both photon and $Z$ intermediate states. Virtual corrections are calculated analytically in $4 - 2 ε$ dimensions, together with the soft approximation to the real emission diagrams. After cancellation of in

Patrick J. O&#39;Donnell, Q. P. Xu, Humphrey K. K. Tung

Corrections to the exact heavy--quark symmetry results are expected to follow the $1/m_{Q}$ mass effect of the heavy--quark. We show, by an explicit calculation, that there is something other than the mass effect that suppresses the breaking of the spin symmetry.

A. L. Ayala, M. B. Gay Ducati, E. M. Levin

The Glauber approach to the gluon density in a nucleus, suggested by A. Mueller, is developed and studied in detail. Using the GRV parameterization for the gluon density in a nucleon, the value as well as energy and $Q^2$ dependence of the gluon density in a nucleus is calculated. It is shown that the shadowing corrections are under theoretical control and a

S. Kanemura, T. Kubota, H. -A. Tohyama

The radiative corrections to the decay processes of the neutral ($CP$-even) Higgs boson ($H$) into a longitudinal gauge boson pair, {\it i.e.}, $H \rightarrow Z_{L}Z_{L}$ and $H \rightarrow W_{L}^{+}W_{L}^{-}$ are analyzed in the two-Higgs doublet model by assuming that all of the Higgs boson masses are much greater than the $W$ and $Z$ bosons&#39;. These ca

Uma Mahanta

CP violating dipole moments of leptons vanish at least to three loop order and are estimated to be $({m_l\over Mev})\times 1.6\times 10^{- 40}$ e-cm in the standard model (SM), where $m_l$ is the mass of the lepton. However they can receive potentially large contributions in some beyond SM scenarios and this makes them very sensitive probes of new physics. I

A. Bottino, G. Mignola, M. Olechowski, S. Scopel

We examine the properties of relic neutralinos in the regions of the parameter space selected by recent fits to all the electroweak observables within the Minimal Supersymmetric Standard Model. We discuss the relic neutralino cosmic abundance and the direct detection rates for these most likely supersymmetric configurations. We employ the relevant experiment

Cai-Dian Lu, Da-Xin Zhang

We study the loop induced rare decays $B_s(B_d)\toγν\barν$ within the standard model. Both constituent quark model and pole model are used and the branching ratios turn out to be of the orders of $10^{-8}$ for $B_s\to γν\bar ν$ and $10^{-9}$ for $B_d \to γν\bar ν$. These processes can be served to determine the decay constants of $B_s$ and $B_d$.

G. Z. Machabeli, A. D. Rogava

A recently proposed &#34;gedanken experiment&#34; [G.Z. Machabeli and A.D. Rogava. Phys. Rev. A {\bf 50}, 98 (1994)], exhibiting surprising behavior, is reexamined. A description of this behavior in terms of the laboratory inertial frame is presented, avoiding uncertainties arising due to a definition of a centrifugal force in relativity. The surprising anal

A. D. Rogava, G. R. Khujadze

The general scheme for the construction of the general-relativistic model of the magnetically driven jet is suggested. The method is based on the usage of the 3+1 MHD formalism. It is shown that the critical points of the flow and the explicit radial behavior of the physical variables may be derived through the jet ``profile function.&#34;

R. Beig, Piotr T. Chrusciel

We study space-time Killing vectors in terms of their &#34;lapse and shift&#34; relative to some spacelike slice. We give a necessary and sufficient condition in order for these lapse-shift pairs, which we call Killing initial data (KID&#39;S), to form a Lie algebra under the bracket operation induced by the Lie commutator of vector fields on space-time. Thi

T Dereli, M Önder, J Schray, R W Tucker

We argue that all Einstein-Maxwell or Einstein-Proca solutions to general relativity may be used to construct a large class of solutions (involving torsion and non-metricity) to theories of non-Riemannian gravitation that have been recently discussed in the literature.