November 1998 arXiv papers — page 19

Jarmo Hietarinta, Petri Salo

We have studied numerically Faddeev-Hopf knots, which are defined as those unit-vector fields in $R^3$ that have a nontrivial Hopf charge and minimize Faddeev's Lagrangian. A given initial configuration was allowed to relax into a (local) minimum using the first order dissipative dynamics corresponding to the steepest descent method. A linked combination

A. J. M. Medved, G. Kunstatter

We consider the most general diffeomorphism invariant action in 1+1 spacetime dimensions that contains a metric, dilaton and Abelian gauge field, and has at most second derivatives of the fields. Our action contains a topological term (linear in the Abelian field strength) that has not been considered in previous work. We impose boundary conditions appropria

A. K. Biswas, J. Maharana, R. K. Pradhan

The consequences of holography hypothesis are investigated for the Pre-big-bang string cosmological models. The evolution equations are obtained from the tree level string effective action. It is shown that $S/A$ is bounded by a constant in each case, $S$ being the entropy within the volume bounded by the horizon of area $A$.

L. Griguolo

The instanton contributions to the partition function and to homologically trivial Wilson loops for a U(N) Yang-Mills theory on a torus $T^2$ are analyzed. An exact expression for the partition function is obtained as a sum of contributions localized around the classical solutions of Yang-Mills equations, that appear according to the general classification o

Jin-Ho Cho

We study the effect of the gravitational Chern-Simons term (GCST) in the (2+1)-dimensional anti-de Sitter (AdS$_{2+1}$) geometry. In the context of the gauge gravity, we obtain black hole solution and its boundary WZW theory. The BTZ black hole solution can still be retrieved but its gravitational mass and angular momentum become different from their inheren

Takeo Moroi

The SUSY CP problem in the framework of gauge mediated SUSY breaking model is considered. We first discuss the electric dipole moments of the electron and neutron, which are likely to be larger than the experimental upper bound if all the phases in the Lagrangian are O(1). We derive a constraint on the phases in the so-called $μ$- and $B_μ$-parameters and ga

Anjan S. Joshipura, Saurabh D. Rindani

We discuss an extended SU(2)XU(1) model which naturally leads to mass scales and mixing angles relevant for understanding both the solar and atmospheric neutrino anomalies in terms of the vacuum oscillations of the three known neutrinos. The model uses a softly broken L_e-L_μ-L_τ symmetry and contains a heavy scale M_H\sim 10^{15} GeV. The L_e-L_μ-L_τ symmet

Mayumi Aoki, Gi-Chol Cho, Noriyuki Oshimo

In the supersymmetric standard model, the radiative $B$-meson decay $B \to X_s γ$ could receive a large contribution from a new source of flavor-changing neutral current, which also violates CP invariance. The CP-conjugate processes then may sizably differ in decay width. If a new CP-violating phase is not suppressed, this decay rate asymmetry can be signifi

André Peshier

The extrapolation of truncated perturbative series to the large coupling regime is not reliable since the accuracy of the calculations cannot be improved systematically by a finite set of higher order terms. Instead, a nonperturbative approach is proposed here to describe the thermodynamics of strongly coupled plasmas. Within the $ϕ^4$ theory, it is derived

G. C. Rossi

We discuss a number of old and new methods for computing $K\toππ$ amplitudes on the lattice. They all involve a non-perturbative determination of matching coefficients. We show how problems related to operator mixing can be greatly reduced by using point-split hadronic currents.

Michael Kobel, representing the LEP collaborations

Recent LEP results on single and pair production of neutral electroweak gauge bosons are reviewed. QED and Electroweak gamma-e Compton scattering at LEP covers gamma-e center-of-mass energies sqrt{shat} in the range from about 20 GeV to 170 GeV, and leads to single production of on-shell gamma, off-shell gamma*, and Z bosons, also known as ``Zee'' pr

J. M. Conrad

This article reviews the many new results from neutrino oscillation searches which were presented at ICHEP '98. Exciting indications of neutrino oscillations have been seen in the solar neutrino deficit, atmospheric neutrino deficit and LSND excess. These indications and reported limits on oscillations are considered. Attempts to develop a theory which a

J. M. LoSecco

A reanalysis of identified muon neutrino interactions from IMB 3 yields bounds on $\sin^{2}(2 θ)$ and $Δm^{2}$. The limit $\sin^{2}(2 θ) < 0.72$ is in conflict with the recent announcement of a neutrino mass.

L. C. Garcia de Andrade

A technique for generating spherically symmetric dislocation solutions of a direct Poincaré gauge theory of gravity based on homogeneous functions which makes Cartan torsion to vanish is presented.Static space supported dislocation and time dependent solutions are supplied.Photons move along geodesics in analogy to geodesics described by electrons around dis

L. C. Garcia de Andrade

An exact solution of Einstein-Cartan-Maxwell (ECM) field equations representing a charged domain wall given by the jump on the electric charge and spin density across the wall is obtained from the Riemannian theory of distributions. The Gauss-Coddazzi equations are used to show that spin, charge and Cartan torsion increases the repulsive character of the dom

Sudip Chakravarty, Hae-Young Kee, Elihu Abrahams

The theory that the change of the electronic kinetic energy in a direction perpendicular to the CuO-planes in high-temperature superconductors is a substantial fraction of the condensation energy is examined. It is argued that the consequences of this theory based on a rigorous $c$-axis conductivity sum rule are consistent with recent optical and penetration

Hemant Bokil, A. J. Bray, Barbara Drossel, M. A. Moore

In a recent letter Marinari et al [Phys. Rev. Lett. 81, 1698 (1998)] introduced a new method to study spin glass transitions and argued that by probing replica symmetry (RS) as opposed to time reversal symmetry (TRS), their method unambiguously shows that replica symmetry breaking (RSB) occurs in short-range spin glasses. In this comment we show that while t

J. Zaanen

An elementary phenomenological consideration is presented regarding the long wavelength quantum dynamics in cuprate superconductors. The emphasis is on the interplay of the charge- and spin order associated with the stripe phenomenon on the one hand, and superconductivity on the other hand.

A. Amici, M. Montuori

An important problem in the analysis of experimental data showing fractal properties, is that such samples are composed by a set of points limited by an upper and a lower cut off. We study how finite size effect due to the discreteness of the sets may influence self similar properties even far from these cut-offs. Estimations of these effects are provided on

J. Zaanen, L. F. Feiner, A. M. Oles

The most elementary of all physical spin-orbital models is the Kugel-Khomskii model describing a S=1/2, $e_g$ degenerate Mott-insulator. Recent theoretical work is reviewed revealing that the classical limit is characterized by a point of perfect dynamical frustration. It is suggested that this might give rise to a quantum disordered ground state.

Johann Kroha, Peter W&#34;olfle

The question of Fermi liquid vs. non-Fermi liquid behavior induced by strong correlations is one of the prominent problems in metallic local moment systems. As standard models for such systems, the SU(N)xSU(M) Anderson impurity models exhibit both Fermi liquid and non-Fermi liquid behavior, depending on their symmetry. Taking the Anderson model as an example

Dmitry N. Chigrin, Andrei V. Lavrinenko, Dmitry A. Yarotsky, Sergey V. Gaponenko

We show that under certain conditions one-dimensional dielectric lattice possesses total omnidirectional reflection of incident light. The predictions are verified experimentally using Na3AlF6/ZnSe multilayer structure developed by means of standard optical technology. The structure was found to exhibit reflection coefficient more then 99% in the range of in

R. Cafiero, A. Gabrielli, M. Marsili, M. A. Muñoz

We propose a generalized version of the Dielectric Breakdown Model (DBM) for generic breakdown processes. It interpolates between the standard DBM and its analog with quenched disorder, as a temperature like parameter is varied. The physics of other well known fractal growth phenomena as Invasion Percolation and the Eden model are also recovered for some par

S. Consta, N. B. Wilding, D. Frenkel, Z. Alexandrowicz

We present a new Monte Carlo scheme for the efficient simulation of multi-polymer systems. The method permits chains to be inserted into the system using a biased growth technique. The growth proceeds via the use of a retractable feeler, which probes possible pathways ahead of the growing chain. By recoiling from traps and excessively dense regions, the grow

T. Gonzalez, J. Mateos, D. Pardo, O. M. Bulashenko

We present a theoretical investigation of shot-noise suppression due to long-range Coulomb interaction in nondegenerate diffusive conductors. Calculations make use of an ensemble Monte Carlo simulator self-consistently coupled with a one-dimensional Poisson solver. We analyze the noise in a lightly doped active region surrounded by two contacts acting as the

Y. Shibata, T. Tohyama, S. Maekawa

We examine the effect of the magnetic frustration J&#39; on the single-hole spectral function in the t-t&#39;-t&#39;&#39;-J model. At zero temperature, the exact diagonalization (ED) and the self-consistent Born approximation (SCBA) methods are used. We find that the frustration suppresses the quasiparticle (QP) weight at small momentum k, whereas the QP pea

Anders Johansen, Didier Sornette

We propose that the minimal requirements for a model of stock market price fluctuations should comprise time asymmetry, robustness with respect to connectivity between agents, ``bounded rationality&#39;&#39; and a probabilistic description. We also compare extensively two previously proposed models of log-periodic behavior of the stock market index prior to

E. Menendez-Proupin, C. Trallero-Giner, A. Garcia-Cristobal

A theoretical model of resonant hyper-Raman scattering by an ensemble of spherical semiconductor quantum dots has been developed. The electronic intermediate states are described as Wannier-Mott excitons in the framework of the envelope function approximation. The optical polar vibrational modes of the nanocrystallites (vibrons) and their interaction with th

Mincheol Shin, Seongjae Lee, Kyoung Wan Park, El-Hang Lee

In the ring-shaped tunnel-junction array with four islands, the secondary Coulomb blockade gap in a low bias-voltage range is observed in the I-V characteristics. We attribute its appearance to the unique topology of the array which induces up to two electrons to get trapped inside. We have analyzed the formation and destruction of the gap in terms of detail

Robert C. Elson, Allen I. Selverston, Ramon Huerta, Nikolai F. Rulkov

We report experimental studies of synchronization phenomena in a pair of biological neurons that interact through naturally occurring, electrical coupling. When these neurons generate irregular bursts of spikes, the natural coupling synchronizes slow oscillations of membrane potential, but not the fast spikes. By adding artificial electrical coupling we stud

D. Calzetti, T. M. Heckman

(Abridged) We investigate the evolution of the opacity of galaxies as a function of redshift, using simple assumptions about the metal and dust enrichment of the gas and the distribution of dust in galaxies. We use an iterative procedure to reconstruct the intrinsic Star Formation Rate (SFR) density of galaxies with redshift, by applying dust obscuration cor

B. M. Gaensler, B. W. Stappers, D. A. Frail, S. Johnston

Previous searches for radio pulsar wind nebulae (PWN) suggest that only the youngest and most energetic pulsars power PWN. However the selection effects associated with such searches are severe, in that emission from a faint compact PWN will be masked by that from its associated pulsar. This has motivated us to search for radio PWN using the technique of pul

R. C. Kraan-Korteweg, W. van Driel, F. Briggs, B. Binggeli

A radio spectroscopic driftscan survey in the 21cm line with the Nancay Radio Telescope of 0.08 steradians of sky in the direction of the constellation Canes Venatici covering a heliocentric velocity range of -350 < V_hel < 2350 km/s produced 53 spectral features, which was further reduced to a sample of 33 reliably detected galaxies by extensive follow-up o

G. L. Hoffman, N. Y. Lu, E. E. Salpeter, B. M. Connell

Neutral hydrogen synthesis mapping of NGC 4532 and DDO 137, a pair of Sm galaxies on the edge of the Virgo cluster, is used to determine rotation curves for each of the galaxies and to resolve the structure and kinematics of three distinct HI concentrations embedded in an extended envelope of diffuse HI discovered in earlier Arecibo studies of the system. Th

P. Andreani, H. Boehringer, G. Dall&#39;Oglio, L. Martinis

We report simultaneous observations at 1.2 and 2 mm, with a double channel photometer on the SEST Telescope, of the X-ray cluster RXJ0658-5557 in search for the Sunyaev-Zel&#39;dovich (S-Z). The S-Z data were analyzed using the relativistically correct expression for the Comptonization parameter and we find from the detected decrement (2.60 +/- 0.79) ~ 10^{-

Joshua E. Barnes

Interacting galaxies are a natural arena for studies of non-equilibrium stellar dynamics, gas dynamics, and thermodynamics. Only galaxy formation itself is as deeply concerned with as many different aspects of dynamics, and the connection between interactions and the formation of galaxies is probably no coincidence. This review discusses tidal interactions,

Joshua E. Barnes

This review focus on some issues which seem relevant to recent discussions: (1) how halo structure influences tail length, (2) the fate of power-law density cusps, (3) the results of unequal-mass disk galaxy mergers, and (4) the behavior of hot and cold gas in merging disk galaxies.

Mark Wardle, Farhad Yusef-Zadeh, T. R. Geballe

OH(1720 MHz) masers permit direct measurements of the magnetic field strength at the Galactic Centre, and their angular broadening constrains models for the medium that scatters radio waves in the central 100 pc of the Galaxy. As the 1720 MHz masers are unaccompanied by the main-line masers at 1665 and 1667 MHz, they must be pumped by collisions in molecular

Matthew Colless, David Burstein, Roger L. Davies, Robert K. McMahan

We examine the Mg-sigma relation for early-type galaxies in the EFAR sample and its dependence on cluster properties. A maximum likelihood fit gives global Mg-sigma relations of Mgb&#39;=0.131log(sigma)-0.131 and Mg2=0.257log(sigma)-0.305, with intrinsic scatter of 0.016 mag in Mgb&#39; and 0.023 mag in Mg2. The zeropoint for cD galaxies is higher than for E

M. S. Brotherton, Paul J. Francis

Statistical investigations of samples of quasars have established that clusters of properties are correlated. The strongest trends among the ultraviolet emission-line properties are characterized by the object-to-object variation of emission from low-velocity gas, the so-called ``intermediate-line region&#39;&#39; or ILR. The strongest trends among the optic

John Bally, Bo Reipurth, Charles J. Lada, Youssef Billawala

We present a millimeter wave study of a cluster of bipolar CO outflows embedded in the western end of the Circinus molecular cloud complex, G317-4, that is traced by very high optical extinction. For an assumed distance of 700 pc, the entire Circinus cloud is estimated to have a mass of about 5E4 solar masses. The opaque western portion that was mapped in th

Ziv Ran

We consider normal projective n-dimensional varieties X whose anticanonical divisor class -K is ample and where every Weil divisor is a rational multiple of K. The index i is the largest integer such that K/i exists as a Weil divisor. We show (i) if X has log-terminal singularities, and in addition 1-forms on the smooth part of X are holomorphic on a resolut

D. A. Dimitrov, D. Louca, H. Röder

The spherically averaged structure function $\soq$ obtained from pulsed neutron powder diffraction contains both elastic and inelastic scattering via an integral over energy. The Fourier transformation of $\soq$ to real space, as is done in the pair density function (PDF) analysis, regularizes the data, i.e. it accentuates the diffuse scattering. We present

Wouter-Jan Rappel, Alastair Nicol, Armand Sarkissian, Herbert Levine

We present results of experiments on the dynamics of Dictyostelium discoideum in a novel set-up which constraints cell motion to a plane. After aggregation, the amoebae collect into round &#39;&#39;pancake&#34; structures in which the cells rotate around the center of the pancake. This vortex state persists for many hours and we have explicitly verified that

Chuan Liu

We study aspects concerning numerical simulations of Lattice QCD with two flavors of dynamical Ginsparg-Wilson quarks with degenerate masses. A Hybrid Monte Carlo algorithm is described and the formula for the fermionic force is derived for two specific implementations. The implementation with optimal rational approximation method is favored both in CPU time

B. F. L. Ward, S. Jadach, M. Melles, S. A. Yost

We consider the error budget for the calculation of the LEP/SLC luminosity in the Monte Carlo event generator BHLUMI4.04 from the standpoint of new calculations of the exact result for the O(alpha) correction to the process e+ e- -> e+ e- + gamma in the low angle luminosity regime at SLC/LEP energies, for the double bremsstrahlung effect e+ e- -> e+ e- + gam

Hyok-Jon Kwon

We study order parameter fluctuation effects in the superconducting state as a possible precursor to the pseudogap phenomena. Using a low-energy effective theory in the d-wave BCS model, we self-consistently calculate the single-particle properties. We find that the fluctuations reduce the spectral gap, and the shape of the gap is deformed, showing reduced s

J. Wildeshaus

Let (P,X) be Shimura data, M=M(P,X,K) the Shimura variety of level K. To an algebraic representation of P, one can associate a mixed sheaf (variation of Hodge structure, l-adic sheaf) on M. In the paper, we study the degeneration of such sheaves along strata in toroidal compactifications of M. The main result (2.8 in the Hodge setting, 3.9 in the l-adic sett

Mario Castagnino, Susana Landau, Fernando C. Lombardo

We consider a simple cosmological model in order to show the importance of unstable particle creation for the validity of the semiclassical approximation. Using the mathematical structure of rigged Hilbert spaces we show that particle creation is the seed of decoherence which enables the quantum to classical transition.

S. Bronoff, C. P. Korthals Altes

Thermally reduced QCD leads to three dimensional SU(3) gaugefields coupled to an adjoint scalar field $A_0$. We compute the effective potential in the one-loop approximation and evaluate the VEV&#39;s of $TrA_0^2$ and $TrA_0^3$. In the Higgs phase not only the former, but also the latter has a VEV. This happens where the SU(3) gauge symmetry is broken minima

Christoph Stadler, Harald Lange, Friederike Schmid

We present Monte Carlo simulations of a coarse-grained model for Langmuir monolayers of amphiphile molecules on a polar substrate. The molecules are modelled as chains of Lennard-Jones beads, with one slightly larger end bead confined in a planar surface. They are simulated in continuous space under conditions of constant pressure, using a simulation box of

Burkhard Seif, Tilo Wettig, Thomas Guhr

We use the graded eigenvalue method, a variant of the supersymmetry technique, to compute the universal spectral correlations of the QCD Dirac operator in the presence of massive dynamical quarks. The calculation is done for the chiral Gaussian unitary ensemble of random matrix theory with an arbitrary Hermitian matrix added to the Dirac matrix. This case is

J. Dennett-Thorpe, A. H. Bridle, R. A. Laing, P. A. G. Scheuer

We investigate the correlations between spectral index, jet side and extent of the radio lobes for a sample of nearby FRII radio galaxies. In Dennett-Thorpe et al. (1997) we studied a sample of quasars and found that the high surface brightness regions had flatter spectra on the jet side (explicable as a result of Doppler beaming) whilst the extended regions

T. A. Armstrong

We present results from Experiment 864 for antiproton production and antideuteron limits in Au + Pb collisions at 11.5 GeV/c per nucleon. We have measured invariant multiplicities for antiprotons for rapidities 1.4<y<2.4 at low transverse momentum as a function of collision geometry. When compared with the results from Experiment 878 our measurements suggest

L. Bassani, M. Dadina, R. Maiolino, M. Salvati

We present and discuss a "3-dimensional" diagnostic diagram for Seyfert2 galaxies obtained by means of X-ray and [OIII] data on a large sample of objects (reported in the Appendix). The diagram shows the Kalpha iron line equivalent width as a function of both the column density derived from the photoelectric cutoff and the 2-10 keV flux normalized to the [OI

R. Cowsik, B. V. Sreekantan

Recently Coleman and Glashow [1] have developed a model which allows the introduction of a small violation of Lorentz invariance. Observational signatures arise because this interaction also violates flavor conservation and allows the radiative decay of the muon, $μ\to e + γ$, whose branching ratio increases as b $γ^4$ where $γ$ is the Lorentz factor of the

John D. Barrow, Joao Magueijo

Big Bang models of the Universe predict rapid domination by curvature, a paradox known as the flatness problem. Solutions to this problem usually leave the Universe exactly flat for every practical purpose. Explaining a nearly but not exactly flat current Universe is a new problem, which we label the quasi-flatness problem. We show how theories incorporating

Hongsu Kim

Existence check of non-trivial, stationary axisymmetric black hole solutions in Brans-Dicke theory of gravity in different direction from those of Penrose, Thorne and Dykla, and Hawking is performed. Namely, working directly with the known explicit spacetime solutions in Brans-Dicke theory, it is found that non-trivial Kerr-Newman-type black hole solutions d

W. Lee, D. Weingarten

We evaluate the continuum limit of the valence approximation to the mass of scalar quarkonium and to the scalar quarkonium-glueball mixing energy for a range of different quark masses. Our results answer several questions raised by the proposed identification of $f_0(1710)$ as composed primarily of the lightest scalar glueball.

Joachim Kupsch

Superselection rules induced by the interaction with the environment are a basis to understand the emergence of classical observables within quantum theory. The aim of this article is to investigate the decoherence effects, which lead to superselection sectors, with the help of exactly soluble Hamiltonian models. Starting from the examples of Araki and of Zu

Giampiero Esposito

The Schrodinger equation for stationary states in a central potential is studied in an arbitrary number of spatial dimensions, say q. After transformation into an equivalent equation, where the coefficient of the first derivative vanishes, it is shown that in such equation the coefficient of the second inverse power of r is an even function of a parameter, s

J. A. Morgan

An exotic spacecraft propulsion technology is described which exploits parity violation in weak interactions. Anisotropic neutrino emission from a polarized assembly of weakly interacting particles converts rest mass directly to spacecraft impulse.

U. Vietze, O. Krauß, F. Laeri, G. Ihlein

We present a new class of micro lasers based on nanoporous molecular sieve host-guest systems. Organic dye guest molecules of 1-Ethyl-4-(4-(p-Dimethylaminophenyl)-1,3-butadienyl)-pyridinium Perchlorat were inserted into the 0.73-nm-wide channel pores of a zeolite AlPO$_4$-5 host. The zeolitic micro crystal compounds where hydrothermally synthesized according

E. Garrido, D. V. Fedorov, A. S. Jensen

We use a three-body model to investigate breakup reactions of 11Li (n+n+9Li) on a light target. The interaction parameters are constrained by known properties of the two-body subsystems, the 11Li binding energy and fragmentation data. The remaining degrees of freedom are discussed. The projectile-target interactions are described by phenomenological optical

C. Hartnack, Rajeev K. Puri, J. Aichelin, J. Konopka

Basic problems of the semiclassical microscopic modelling of strongly interactingsystems are discussed within the framework of Quantum Molecular Dynamics (QMD). This model allows to study the influence of several types of nucleonic interactions on a large variety of observables and phenomena occurring in heavy ion collisions at relativistic energies.It is sh

J. E. Garcia--Ramos, P. Van Isacker

The isospin-invariant interacting boson model IBM-3 is analyzed in situations where $SU_T(3)$ charge symmetry [or, equivalently, $U_L(6)$ $sd$ symmetry] is conserved. Analytic expressions for energies, electromagnetic transitions, two-nucleon transfer probabilities, and boson-number expectation values are obtained for the three possible dynamical symmetry li

R. Simon, S. Chaturvedi, V. Srinivasan

It is shown that a $N\times N$ real symmetric [complex hermitian] positive definite matrix $V$ is congruent to a diagonal matrix modulo a pseudo-orthogonal [pseudo-unitary] matrix in $SO(m,n)$ [ $SU(m,n)$], for any choice of partition $N=m+n$. It is further shown that the method of proof in this context can easily be adapted to obtain a rather simple proof o

M Krishna, J Obermeit

In this paper we consider sparsely random potentials in 5 or more dimensional cubic lattice and exhibit localized and extended states. We identify also the mobility edge for a class of potentials going to infinity at infinity. Our treatment includes a large class of unperturbed selfadjoint opeartors commuting with the usual Laplacian on the lattice.

Stavros Garoufalidis

Recently, Mullins calculated the Casson-Walker invariant of the 2-fold cyclic branched cover of an oriented link in S^3 in terms of its Jones polynomial and its signature, under the assumption that the 2-fold branched cover is a rational homology 3-sphere. Using elementary principles, we provide a similar calculation for the general case. In addition, we cal

Alexander Dynin

Our rigorous path integrals costruction for the evolution operators is extended to metric-affine manifolds.

K. Erdmann, R. M. Green

We study some non-semisimple representations of affine Temperley--Lieb algebras and related cellular algebras. In particular, we classify extensions between simple standard modules. Moreover, we construct a completion which is an infinite dimensional cellular algebra.

J. Van der Jeugt, R. B. Zhang

The multiplicities a_{lambda,mu} of simple modules L(mu) in the composition series of Kac modules V(lambda) for the Lie superalgebra gl(m/n) were described by Serganova, leading to her solution of the character problem for gl(m/n). In Serganova&#39;s algorithm all mu with nonzero a_{lambda,mu} are determined for a given lambda; this algorithm turns out to be

Klaus Mohnke

We use an estimate on the Thurston--Bennequin invariant of a Legendrian link in terms of its Kauffman-polynomial to show that links of topological unknots, e.g. the Borromean rings or the Whithead link, may not be represented by Legendrian links of Legendrian unknots.

D. Nikshych, L. Vainerman

We characterize finite index depth 2 inclusions of type II_1 factors in terms of actions of weak Kac algebras and weak C*-Hopf algebras. If N\subset M \subset M_1 \subset M_2 \subset ... is the Jones tower constructed from such an inclusion N\subset M, then B=M^\prime \cap M_2 has a natural structure of a weak C*-Hopf algebra and there is a minimal action of

D. Nikshych, L. Vainerman

We establish the equivalence of three versions of a finite dimensional quantum groupoid: a generalized Kac algebra introduced by T. Yamanouchi, a weak $C^*$-Hopf algebra introduced by G. Bohm, F. Nill and K. Szlachanyi (with an involutive antipode), and a Kac bimodule -- an algebraic version of a Hopf bimodule, the notion introduced by J.-M. Vallin. We also

M. De Francia, H. Falomir, M. Loewe

We introduce the chemical potential in a system of two-flavored massless fermions in a chiral bag by imposing boundary conditions in the Euclidean time direction. We express the fermionic mean number in terms of a functional trace involving the Green function of the boundary value problem, which is studied analytically. Numerical evaluations for the fermioni

G. W. Gibbons, P. Rychenkova

We describe some single-sided BPS domain wall configurations in M-theory. These are smooth non-singular resolutions of Calabi--Yau orbifolds obtained by identifying the two sides of the wall under reflection. They may thus be thought of as domain walls at the end of the universe. We also describe related domain wall type solutions with a negative cosmologica

Ian D. Lawrie

A complete set of Feynman rules is derived, which permits a perturbative description of the nonequilibrium dynamics of a symmetry-breaking phase transition in $λϕ^4$ theory in an expanding universe. In contrast to a naive expansion in powers of the coupling constant, this approximation scheme provides for (a) a description of the nonequilibrium state in term

Mohsen Alishahiha

In this article we consider some properties of the (0,2) theory using AdS/ CFT correspondence. We also consider the &#34;string baryonic state&#34; of the theory. We will show that stable baryon states for $k$ string exist provided $2/3 N \leq k \leq N$. The (0,2) theory in the finite temperature is also considered using Schwarzshild geometry, giving informa

A. Gonzalez-Arroyo

Following two different tracks, we arrive at a definition of Nahm&#39;s transformation valid for self-dual fields on the 4-dimensional torus with non-zero twist tensor.The transform is again a self-dual gauge field defined on a new torus and with non-zero twist tensor. It preserves the property of being an involution.

Takao Koikawa

We connect the discrete and continuous Bogomolny equations. There exists one-parameter algebra relating two equations which is the deformation of the extended conformal algebra. This shows that the deformed algebra plays the role of the link between the matrix valued model and the model with one more space dimension higher.

D. J. Muller, S. Nandi

We consider the phenomenology of GMSB models where the lighter stau is the next to lightest supersymmetric particle. In this situation, the dominant signals for supersymmetry are events with two or three high p_T tau leptons accompanied by large missing transverse energy. We find that the inclusive two tau jets signature could be observable at the Tevatron&#

L. E. Gordon, G. P. Ramsey

QCD motivated polarized parton distributions, evolved directly in x-space, are used to predict rates for prompt photon and Jet production at RHIC and HERA-N center of mass energies. Various scenarios for the polarized gluon distributions are considered and compared, and the possibility of using large p_T processes in polarized pp collision experients to choo

Fred Cooper

jWe review recent research on Initial Value Problems in Quantum Field Theory. We pay special attention to the chiral phase transition in the linear sigma model. We discuss conditions for the development of Disoriented Chiral Condensates and show how their presence affects both the pion inclusive distribution and the dilepton distribution. We discuss the use

L. E. Gordon

QCD motivated polarized parton distributions, evolved directly in $x$-space, are used to predict rates for prompt photon production at RHIC centre of mass energies. Various scenarios for the polarized gluon distributions are considered and compared, and the possibility of using large $p_T$ processes in polarized $pp$ collision experiments to choose between t

N. Hammon, H. Stöcker, W. Greiner

We calculate the shadowing of sea quarks and gluons and show that the shadowing of gluons is {\it not} simply given by the sea quark shadowing, especially at small $x$. The calculations are done in the lab frame approach by using the generalized vector meson dominance model. Here the virtual photon turns into a hadronic fluctuation long before the nucleus. T

Ernest Ma, Martti Raidal, Utpal Sarkar

We show that if a baryon asymmetry of the universe is generated through the out-of-equilibrium decays of heavy scalar bilinears coupling to two fermions of the minimal standard model, it is necessarily an asymmetry conserving $(B-L)$ which cannot survive past the electroweak phase transition because of sphalerons. We then show that a surviving $(B-L)$ asymme

Andre H. Hoang, Zoltan Ligeti, Aneesh V. Manohar

Theoretical predictions for B decay rates are rewritten in terms of the Upsilon(1S) meson mass instead of the b quark mass, using a modified perturbation expansion. The theoretical consistency of this expansion is shown both at low and high orders. Our method improves the behavior of the perturbation series for semileptonic and nonleptonic inclusive decay mo

S. Jaimungal, G. W. Semenoff, K. Zarembo

We demonstrate that, due to the finite thickness of domain walls, and the consequent ambiguity in defining their locations, the effective string description obtained by integrating out bulk degrees of freedom contains ambiguities in the coefficients of the various geometric terms. The only term with unambiguous coefficient is the zeroth order Nambu-Goto term

Tao Han, JoAnne L. Hewett

The possibility of exploring the flavor changing neutral current $tcZ/tcγ$ couplings in the production vertex for the reaction $\epem\to t\bar c + \bar tc$ is examined. Using a model independent parameterization for the effective Lagrangian to describe the most general three-point interactions, production cross sections are found to be relatively small at LE

Sinya Aoki, Yusuke Taniguchi

We calculate one-loop correction to the axial Ward-Takahashi identity given by Furman and Shamir in domain-wall QCD. It is shown perturbatively that the renormalized axial Ward-Takahashi identity is satisfied without fine tuning and the ``conserved&#39;&#39; axial current receives no renormalization, giving $Z_A=1$. This fact will simplify the calculation of

J. A. Font, M. Miller, W. Suen, M. Tobias

This is the first in a series of papers on the construction and validation of a three-dimensional code for general relativistic hydrodynamics, and its application to general relativistic astrophysics. This paper studies the consistency and convergence of our general relativistic hydrodynamic treatment and its coupling to the spacetime evolutions described by

T. A. Jacobson, G. E. Volovik

An event horizon for &#34;relativistic&#34; fermionic quasiparticles can be constructed in a thin film of superfluid 3He-A. The quasiparticles see an effective &#34;gravitational&#34; field which is induced by a topological soliton of the order parameter. Within the soliton the &#34;speed of light&#34; crosses zero and changes sign. When the soliton moves, t

H. Noh, J. Hwang

We present a set of equations describing the evolution of the scalar-type cosmological perturbation in a gravity with general quadratic order curvature coupling terms. Equations are presented in a gauge ready form, thus are ready to implement various temporal gauge conditions depending on the problems. The Ricci-curvature square term leads to a fourth-order

Robert Ellison, Rick Linger, Thomas Longstaff, Nancy Mead

This paper presents a method for analyzing the survivability of distributed network systems and an example of its application.

E. S. Rodrigues, E. V. Anda, P. Orellana, F. Claro

We study non-linear phenomena in double barrier heterostructures. Systems in 3D under the effect of an external magnetic field along the current and 1D systems are analyzed. Non-linearities are reflected in the I-V characteristic curve as bistabilities, instabilities and time dependent oscillations of the currents. The nature of the non-linear behavior depen

Mikhail V. Velikanov, Raymond Kapral

A Markov chain model for spatially distributed autocatalytic systems with a quadratic reaction rate is considered. An approximate solution for the local probability distribution is obtained in the form of a perturbation expansion for the regimes where diffusion is relatively fast. Using this approximate distribution, properties of the chemical wave fronts fo

J. L. Cohn, C. P. Popoviciu, Q. M. Lin, C. W. Chu

Measurements of thermal conductivity versus temperature over a broad range of doping in YBa$_2$Cu$_3$O$_{6+x}$ and HgBa$_2$Ca$_{n-1}$Cu$_n$O$_{2n+2+δ}$ ($n$=1,2,3) suggest that small domains of localized holes develop for hole concentrations near $p$=1/8. The data imply a mechanism for localization that is intrinsic to the CuO$_2$-planes and is enhanced via

D. Belitz, T. R. Kirkpatrick

These are notes for lectures delivered at the NATO ASI on Dynamics in Leiden, The Netherlands, in July 1998. The main concepts relating to quantum phase transitions are explained, using the paramagnet-to-ferromagnet transition of itinerant electrons as the primary example. Some aspects of metal-insulator transitions are also briefly discussed. The exposition

G. T. Barkema, A. Baumgaertner

We report on Monte Carlo results of diffusion coefficients of lattice star polymers trapped inside a fixed network (de Gennes model). It is found that our data are in agreement with the Helfand-Pearson exponential factor α=0.29. For the pre-exponential power law exponent we find β=2. In contrast to existing theoretical predictions, we find that the number of