December 1993 arXiv papers — page 7

Qimiao Si, M. J. Rozenberg, G. Kotliar, A. E. Ruckenstein

We study a spinless two-band model at half-filling in the limit of infinite dimensions. The ground state of this model in the non-interacting limit is a band-insulator. We identify transitions to a metal and to a charge-Mott insulator, using a combination of analytical, Quantum Monte Carlo, and zero temperature recursion methods. The metallic phase is a non-

J. R. L. de Almeida, S. Coutinho

We construct a real space renormalization group (RG) approach for Ising spin glasses on hypercubic lattices within the scheme of the Migdal-Kadanoff approximation using replicas. Our replica symmetric solution yields results consistent with simple decimation previously obtained and the introduction of breaking of replica symmetry within the RG is discussed,

D. F. Wang, James T. Liu, P. Coleman

We derive the spectrum and the thermodynamics of the one-dimensional supersymmetric t-J model with long range hopping and spin exchange using a set of maximal-spin eigenstates. This spectrum confirms the recent conjecture that the asymptotic Bethe-ansatz spectrum is exact. By empirical determining the spinon degeneracies of each state, we are able to explici

P. Cvitanović, J. -P. Eckmann, P. Gaspard

We establish a formula relating global diffusion in a space periodic dynamical system to cycles in the elementary cell which tiles the space under translations.

Matthias Steinmetz, Ewald Mueller

We present first results concerning the metallicities and stellar populations of galaxies formed in a cosmologically motivated simulation. The calculations include dark matter, gas dynamics, radiation processes, star formation, supernovae feedback, and metal enrichment. A rotating, overdense sphere with a mass of $8\,10^{11}\,$\Msol\ serves as initial model.

Alain Bouquet, Jean Kaplan, Anne-Laure Melchior, Yannick Giraud-Héraud

We describe a project of brown dwarf detection in the dark halo of a galaxy using the microlensing effect. We argue that monitoring pixels instead of stars could provide an enhancement in the number of detectable events. We estimate the detection efficiency with a Monte-Carlo simulation. We expect a ten-fold increase with respect to current experiments. To a

J. M. Maillet

We show that solutions of Pentagon equations lead to solutions of the Tetrahedron equation. The result is obtained in the spectral parameter dependent case.

Masaru Siino

We present a compactified version of the 3-dimensional black hole recently found by considering extra identifications and determine the analytical continuation of the solution beyond its coordinate singularity by extending the identifications to the extended region of the spacetime. In the extended region of the spacetime, we find a topology change and non-t

Shin'ichi Nojiri, I. Oda

It is shown that the general solution of classical equations of motion in two dimensional dilaton gravity proposed by Callan, Giddings, Harvey and Strominger (CGHS) includes a Lorentzian wormhole solution in addition to a black hole solution. We also show that matter perturbation of the wormhole by a shock wave leads to the formation of a black hole where th

E. Nikolov, W. Broniowski, K. Goeke

The electric polarizability of the nucleon is calculated in the soliton approach to the Nambu--Jona-Lasinio model. We analyze the leading-$N_c$ contributions, as well as the effects of rotational $1/N_c$ corrections and $Δ$-$N$ mass splitting. Our model prediction is substantially reduced compared to other soliton calculations, and is closer to the experimen

Jeroen C. Vink

Straight foreward lattice descriptions of chiral fermions lead to actions that break gauge invariance. I describe a method to make such actions gauge invariant (up to global gauge transformations) with the aid of gauge fixing. To make this prescription unambiguous, Laplacian gauge fixing is used, which is free from Gribov ambiguities.

Subir Sachdev

The constraints on the scaling properties of conserved charge densities in the vicinity of a zero temperature ($T$), second-order quantum phase transition are studied. We introduce a generalized Wilson ratio, characterizing the non-linear response to an external field, $H$, coupling to any conserved charge, and argue that it is a completely universal functio

Evalyn Gates, Michael S. Turner

There is good evidence that most of the baryons in the Universe are dark and some evidence that most of the matter in the Universe is nonbaryonic with cold dark matter (cdm) being a promising possibility. We discuss expectations for the abundance of baryons and cdm in the halo of our galaxy and locally. We show that in plausible cdm models the local density

C. Gomez, G. Sierra

In this paper we propose a criteria to establish the integrability of N=2 supersymmetric massive theories.The basic data required are the vacua and the spectrum of Bogomolnyi solitons, which can be neatly encoded in a graph (nodes=vacua and links= Bogomolnyi solitons). Integrability is then equivalent to the existence of solutions of a generalized Yang-Baxte

I. Campos, A. Tarancon

We have numerically studied the trapping problem in a two-dimensional lattice where particles are continuously generated. We have introduced interaction between particles and directionality of their movement. This model presents a critical behaviour with a rich phase structure similar to spin systems. We interpret a change in the asymptotic density of partic

Piljin Yi

We study a vacuum polarization effect in the background of certain dilatonic extremal black hole, known as the cornucopion. Whenever the charged fermions are of any finite mass, the gravitational backreaction to a generic value of a $CP$ nonconserving vacuum angle $θ$ is shown to be important owing to a vacuum energy density which does not vanish deep inside

Xiaochun Luo

COBE has provided us with a whole-sky map of the CBR anisotropies. However, even if the noise level is negligible when the four year COBE data are available, the cosmic variance will prevent us from obtaining information about the Gaussian nature of the primordial fluctuations. This important issue is addressed here by studying the angular bispectrum of the

David A. Cox

A map Y -> P^n is determined by a line bundle quotient of (O_Y)^{n+1}. In this paper, we generalize this description to the case of maps from Y to an arbitrary smooth toric variety. The data needed to determine such a map consists of a collection of line bundles on Y together with a section of each line bundle. Further, the line bundles must satisfy certain

A. Strominger, L. Thorlacius

In certain two-dimensional models, collapsing matter forms a black hole if and only if the incoming energy flux exceeds the Hawking radiation rate. Near the critical threshold, the black hole mass is given by a universal formula in terms of the distance from criticality, and there exists a scaling solution describing the formation and evaporation of an arbit

Jiří Witzany

Let $U_0,U_1$ be two normal measures on $κ.$ We say that $U_0$ is in the Mitchell ordering less then $U_1,$ $U_0\vartriangleleft U_1,$ if $U_0 \in Ult(V,U_1) .$ The ordering is well-known to be transitive and well-founded. It has been an open problem to find a model where the Mitchell ordering embeds the four-element poset $|\; | .$ We show that in the Kunen

John Harnad, P. Winternitz

Classical integrable Hamiltonian systems generated by elements of the Poisson commuting ring of spectral invariants on rational coadjoint orbits of the loop algebra $\wt{\gr{gl}}^{+*}(2,{\bf R})$ are integrated by separation of variables in the Hamilton-Jacobi equation in hyperellipsoidal coordinates. The canonically quantized systems are then shown to also

A. Achucarro, R. Gregory, J. A. Harvey, K. Kuijken

We investigate recent claims concerning a new class of cosmic string solutions in the Weinberg-Salam model. They have the general form of previously discussed semi-local and electroweak strings, but are modified by the presence of a non-zero W-condensate in the core of the string. We explicitly construct such solutions for arbitrary values of the winding num

J. M. Figueroa-O'Farrill

It has been realised recently that there is no unique way to describe the physical states of a given string theory. In particular, it has been shown that any bosonic string theory can be embedded in a particular $N{=}1$ string background in such a way that the spectrum and the amplitudes of both theories agree. Similarly, it is also known that the amplitudes

H. W. Braden, Takashi Suzuki

The classical (dynamical) $R$-matrices for the 2- and 3-body Calogero-Moser models with elliptic potentials are given. The 3-body case has an interesting nontrivial structure that goes beyond the known ansatz for momentum independent $R$-matrices. The $R$-matrices presented include the dynamical $R$-matrices of Avan and Talon as degenerate cases of the ellip

J. Navarro-Salas, C. F. Talavera

We study the canonical quantization of the induced 2d-gravity and the pure gravity CGHS-model on a closed spatial section. The Wheeler-DeWitt equations are solved in (spatially homogeneous) choices of the internal time variable and the space of solutions is properly truncated to provide the physical Hilbert space. We establish the quantum equivalence of both

L. P. Horwitz

In a previous paper, it was shown that a soluble model can be constructed for the description of a decaying system in analogy to the Lee-Friedrichs model of complex quantum theory. It is shown here that this model also provides a soluble scattering theory, and therefore constitutes a model for a decay scattering system. Generalized second resolvent equations

L. P. Horwitz

The Lee-Friedrichs model has been very useful in the study of decay-scattering systems in the framework of complex quantum mechanics. Since it is exactly soluble, the analytic structure of the amplitudes can be explicitly studied. It is shown in this paper that a similar model, which is also exactly soluble, can be constructed in quaternionic quantum mechani

Antero Hietamäki

We review the derivation of the Atiyah-Singer and Callias index theorems using the recently developed localization method to calculate exactly the relevant supersymmetric path integrals. (Talk given at the III International Conference on Mathematical Physics, String Theory and Quantum Gravity, Alushta, Ukraine, June 13-24, 1993)

Jürgen Fuchs

The quantum symmetry of a rational quantum field theory is a finite- dimensional multi-matrix algebra. Its representation category, which determines the fusion rules and braid group representations of superselection sectors, is a braided monoidal C^*-category. Various properties of such algebraic structures are described, and some ideas concerning the classi

Dieter Luest

We construct new four-dimensional superstring vacua with extended superconformal symmetries. A non-trivial dilaton background implies the existence of Abelian killing symmetries. These are used to construct dual equivalent backgrounds in a way preserving the N=2 superconformal invariance.

Wojciech Mulak

The $SU(2,2)$-harmonic oscillator on the phase space ${\cal A}(2,2)= {SU(2,2)}/{S(U(2)\times U(2))}$ is quantized using the coherent states. The quantum Hamiltonian is the Toeplitz operator corresponding to the square of the distance with respect to the $SU(2,2)$-invariant Kähler metric on the phase space. Its spectrum, depending on the choice of representat

A. Borowiec, V. K. Kharchenko, Zbigniew Oziewicz

A free differential for an arbitrary associative algebra is defined as a differential with a uniqueness property. The existence problem for such a differential is posed. The notion of optimal calculi for given commutation rules is introduced and an explicit construction of it for a homogenous case is provided. Some examples are presented.

Zbigniew Oziewicz, Eugen Paal, Jerzy Różański

The (co)homology theory of n-ary (co)compositions is a functor associating to $n$-ary (co)composition a complex. We present unified approach to the cohomology theory of coassociative and Lie coalgebras and for $2n$-ary cocompositions. This approach points to a possible generalization.

Jens Hoppe, Q-Han Park

Using a formalism of minitwistors, we derive infinitely many conserved charges for the $sl(\infty )$-Toda equation which accounts for gravitational instantons with a rotational Killing symmetry. These charges are shown to form an infinite dimensional algebra through the Poisson bracket which is isomorphic to two dimensional area preserving diffeomorphism wit

H. -T. Sato

We find a quantum group structure in two-dimensional motion of nonrelativistic electrons in a uniform magnetic field on a torus. The representation basis of the quantum algebra is composed of the quantum Hall wavefunctions proposed by Haldane-Rezayi at the Landau-level filling factor $ν=1/m$ ($m$ odd). It is also shown that the quantum group symmetry is rele

Itzhak Bars

In two dimensions large N QCD with quarks, defined on the plane, is equivalent to a modified string theory with quarks at the ends and taken in the zero fold sector. The equivalence that was established in 1975 was expressed in the form of an interacting string action that reproduces the spectrum and the 1/N interactions of 2D QCD. This action may be a start

K. de Vos, P. van Driel

We study the representation theory of finite W-algebras. After introducing parabolic subalgebras to describe the structure of W-algebras, we define the Verma modules and give a conjecture for the Kac determinant. This allows us to find the completely degenerate representations of the finite W-algebras. To extract the irreducible representations we analyse th

Z. Bern, A. G. Morgan

We apply ideas motivated by string theory to improve the calculational efficiency of one-loop weak interaction processes with massive external gauge bosons. In certain cases ``supersymmetry'' relations between diagrams with a fermion loop and with a gauge boson loop hold. This is explicitly illustrated for a particular one-loop standard model process

T. S. Kosmas, G. K. Leontaris, J. D. Vergados

In the present work we review the most prominent lepton flavor violating processes ($μ\ra eγ$, $μ\ra 3e$, $(μ, e)$ conversion, $M-\bar M$ oscillations etc), in the context of unified gauge theories. Many currently fashionable extensions of the standard model are considered, such as: {\it i)} extensions of the fermion sector (right-handed neutrino); {\it ii)}

Takashi Inoue, Sachiko Takeuchi, Makoto Oka

The weak $\Lam N\to NN$ transition is studied in the valence quark model approach. The momentum transfer for this transition is so large that the short-distance two baryon dynamics must be taken into account. The two baryon system is described in the quark cluster model and the weak transition amplitude is calculated by evaluating the matrix elements of the

K. Farakos, K. Kajantie, K. Rummukainen, M. Shaposhnikov

We study the finite temperature transition of SU(2)-Higgs model with lattice Monte Carlo techniques. We use dimensional reduction to transform the original 4-dimensional SU(2)-gauge + fundamental Higgs theory to an effective 3-dimensional SU(2) + adjoint Higgs + fundamental Higgs model. The simulations were performed with Higgs masses of 35 and 80 GeV; in bo

C. T. H. Davies

Calculations of the heavy-heavy spectrum present a good opportunity for precision tests of QCD using lattice techniques. All methods make use of a non-relativistic expansion of the action and its systematic improvement to remove lattice artefacts. There was convincing demonstration this year that these methods work and that the associated perturbation theory

R. D. Kenway

After a brief introduction to the Heavy-Quark Effective Theory (HQET), I review the extraction of the Isgur-Wise function from lattice QCD calculations of the matrix elements for semi-leptonic decays of heavy-light pseudoscalar mesons both into pseudoscalar and into vector mesons. This work is beginning to test the heavy-quark spin-flavour symmetries around

UKQCD Collaboration

First results are obtained for B mesons using a heavy propagator calculated using NRQCD, and a light Wilson propagator. Results from 13 quenched configurations of size 16^3 x 48 at β= 6.0 give a value for f_{B} of less than 200 Mev and a B^{*}-B splitting of 32(8) MeV. Superior signal/noise behaviour is observed over static propagators on the same configurat

S. Olejnik, G. Schierholz

We examine the phase structure of the $CP^3$ model as a function of $θ$ in the weak coupling regime. It is shown that the model has a first order phase transition at small $θ$. We pay special attention to the extrapolation of the data to the infinite volume. It is found that the critical value of $θ$ decreases towards zero as $β$ is taken to infinity.

D. G. Richards

We present results for hadrons containing a strange quark in quenched lattice QCD. We calculate masses and decay constants using 60 gauge configurations with an O(a)-improved fermion action at beta = 6.2. Using the rho mass to set the scale, we find hadron masses within two to three standard deviations of experiment. Direct comparison with experiment for dec

Y. Kuramashi, M. Fukugita, H. Mino, M. Okawa

Method of calculating hadron multi-point functions and disconnected quark loop contributions which are not readily accessible through conventional techniques is proposed. Results are reported for pion-pion, pion-nucleon and nucleon-nucleon scattering lengths and the flavor singlet-non singlet meson mass splitting estimated in quenched QCD.

S. Tertychniy

The problem of the referring of space and time relationships between physical objects in a curved space-time is discussed. The basic notions of column and weak column that could constitute the basis for consistent general relativistic description of measurements of space and time relations are introduced and the corresponding equations are derived. A column

J. G. Russo

We show that absence of space-like boundaries in 1+1 dimensional dilaton gravity implies a catastrophic event at the end point of black hole evaporation. The proof is completely independent of the physics at Planck scales, which suggests that the same will occur in any theory of quantum gravity which only admits trivial space-time topologies.

Guido Magnano, Leszek M. Sokolowski

We argue that in a nonlinear gravity theory, which according to well-known results is dynamically equivalent to a self-gravitating scalar field in General Relativity, the true physical variables are exactly those which describe the equivalent general-relativistic model (these variables are known as Einstein frame). Whenever such variables cannot be defined,

Vu B Ho

A description of electromagnetism as four-dimensional spacetime structure leads to the dynamics of a charged particle being determined only by the four-vector potential and the existence of an electromagnetic field depending on the topological structure of the background spacetime. When the spacetime structure of electromagnetism is complex it is possible to

Robert Alicki, John R. Klauder, Jerzy Lewandowski

The quantum dynamics of a two-dimensional charged spin $1/2$ particle is studied for general, symmetry--free curved surfaces and general, nonuniform magnetic fields that are, when different from zero, orthogonal to the defining two surface. Although higher Landau levels generally lose their degeneracy under such general conditions, the lowest Landau level, t

K. Ziegler

The energy-energy correlation function of the two-dimensional Ising model with weakly fluctuating random bonds is evaluated in the large scale limit. Two correlation lengths exist in contrast to one correlation length in the pure 2D Ising model: one is finite whereas the other is divergent at the critical points. The corresponding exponent of the divergent c

Anirvan M. Sengupta, Antoine Georges

We consider the two channel Kondo model in the Emery-Kivelson approach, and calculate the total susceptibility enhancement due to the impurity $χ_{imp}=χ-χ_{bulk}$. We find that $χ_{imp}$ exactly vanishes at the solvable point, in a completely analogous way to the singular part of the specific heat $C_{imp}$. A perturbative calculation around the solvable po

T. Plefka

A simplified model is introduced and analysed to show, that for the Landau-Lifshitz equation stable, steady state solutions of domain type exist in ferromagnetic systems, strongly driven by external transverse fields. These dynamic domain states are able to describe the drastic reduction of the power absorption found experimentally above the instability of t

P. Focher, G. L. Chiarotti, M. Bernasconi, E. Tosatti

Available simulation methods, suitable to describe solid-solid phase transitions occurring upon increasing of presssure and/or temperature, are based on empirical interatomic potentials: this restriction reduces the predictive power, and thus the general usefulness of numeric simulations in this very relevant field. We present a new simulation scheme which a

M. Brack, R. K. Bhaduri, J. Law, Ch. Maier

The quantum density of states of the Hénon-Heiles potential displays a pronounced beating pattern. This has been explained by the interference of three isolated classical periodic orbits with nearby actions and periods. A singular magnetic flux line, passing through the origin, drastically alters the beats even though the classical Lagrangean equations of mo

Siegfried Grossmann, Detlef Lohse

We extend the numerical simulations of She et al. [Phys.\ Rev.\ Lett.\ 70, 3251 (1993)] of highly turbulent flow with $15 \le$ Taylor-Reynolds number $Re_λ\le 200$ up to $Re_λ\approx 45000$, employing a reduced wave vector set method (introduced earlier) to approximately solve the Navier-Stokes equation. First, also for these extremely high Reynolds numbers

F. R. Bouchet, R. Juszkiewicz

This paper covers the material of our two talks. We describe a series of projects based upon perturbative expansions to follow the gravitational evolution of the one point probability distribution functions (PDFs) for the density contrast field and for the divergence of the corresponding velocity field. The Edgeworth expansion greatly simplifies the problem.

George B. Rybicki, Ian P. Dell'Antonio

The time-dependent spectral profile of a resonance line in a homogeneous expanding medium is studied by numerically solving an improved Fokker-Planck diffusion equation. The solutions are used to determine the time required to reach a quasi-static solution near the line center. A simple scaling law for this relaxation time is derived and is fitted to the num

S. Borgani, P. Coles, L. Moscardini

We show how to simulate the clustering of rich clusters of galaxies using a technique based on the Zel'dovich approximation. This method well reproduces the spatial distribution of clusters obtainable from full N-body simulations at a fraction of the computational cost. We use an ensemble of large--scale simulations to assess the level and statistical si

Dean Alvis, Bernard Johnston, James Madden

This paper is about the local geometry of a real surfaces. It introduces machinery for studying families of subsets which are determined by conditions which are similar to base conditions, but also involve positivity/non-negativity. The methods used are the real spectrum and Zariski's theory of complete ideals.

Bruno Nachtergaele

I discuss the concept of quasi-state decompositions for ground states and equilibrium states of quantum spin systems. Some recent results on the ground states of a class of one-dimensional quantum spin models are summarized and new work in progress is presented. I also outline some challenging open problems and conjectures.

Andre Aeppli, Geert Jan van Oldenborgh, Daniel Wyler

We present a gauge invariant way to compute one loop corrections to processes involving the production and decay of unstable particles.

Michael Freeman, Peter West

We show how to relate the parafermions that occur in the $W_3$ string to the standard construction of parafermions. This result is then used to show that one of the screening charges that occurs in parafermionic theories is precisely the non-trivial part of the $W_3$ string BRST charge. A way of generalizing this pattern for a $W_N$ string is explained. This

Yu-Qi Chen, Yu-Ping Kuang

A set of general relations between the spin-independent and spin-dependent potentials of heavy quark and anti-quark interactions are derived from reparameterization invariance in the Heavy Quark Effective Theory. It covers the Gromes relation and includes some new interesting relations which are useful in understanding the spin-independent and spin-dependent

G. I. Poulis, Howard D. Trottier, R. M. Woloshyn

Extended Abelian monopoles are investigated in SU(2) lattice gauge theory in three dimensions. Monopoles are computed by Abelian projection in several gauges, including the maximal Abelian gauge. The number $N_m$ of extended monopoles in a cube of size $m^3$ (in lattice units) is defined as the number of elementary ($1^3$) monopoles minus antimonopoles in th

Leonid Dickey

A short proof is given to the fact that the additional symmetries of the KP hierarchy defined by their action on pseudodifferential operators, according to Fuchssteiner-Chen-Lee-Lin-Orlov-Shulman, coincide with those defined by their action on $τ$-functions as Sato's Bäcklund transformations. Also a new simple formula for the generator of additional symm

G. W. Gibbons, C. G. Wells

We study dilaton-electrodynamics in flat spacetime and exhibit a set of global cosmic string like solutions in which the magnetic flux is confined. These solutions continue to exist for a small enough dilaton mass but cease to do so above a critcal value depending on the magnetic flux. There also exist domain wall and Dirac monopole solutions. We discuss a m

Nathan Berkovits, Mike Freeman, Peter West

It has recently been shown that the ordinary bosonic string can be represented by a special background of N=1 or N=2 strings. In this paper, it will be shown that the bosonic string can also be represented by a special background of $W$-strings.

V. V. Dodonov, V. I. Man'ko

The effective formulas reducing the two-dimensional Hermite polynomials to the classical (one-dimensional) orthogonal polynomials are given. New one-parameter generating functions for these polynomials are derived. Asymptotical formulas for large values of indices are found. The applications to the squeezed one-mode states and to the time-dependent quantum h

Moshe Moshe

In the limit where $N\to\infty$ and the coupling constant $g \to g_{c}$ in a correlated manner, O(N) symmetric vector models represent filamentary surfaces. The purpose of these studies is to gain intuition for the long lasting search for a possible description of quantum field theory in terms of extended objects. It is shown here that a certain limiting pro

Z. Oziewicz

A bivertical classical field theory include the Newtonian mechanics and Maxwell's electromagnetic field theory as the special cases. This unification allows to recognize the formal analogies among the notions of Newtonian mechanics and Maxwell's electrodynamics.

M. Karowski, A. Zapletal

An $U_q(sl(n))$ invariant transfer matrix with periodic boundary conditions is analysed by means of the algebraic nested Bethe ansatz for the case of $q$ being a root of unity. The transfer matrix corresponds to a 2-dimensional vertex model on a torus with topological interaction w.r.t. the 3-dimensional interior of the torus. By means of finite size analysi

M. B. Gavela, P. Hernández, J. Orloff, O. Pène

Simply based on CP arguments, we argue against a Standard Model explanation of the baryon asymmetry of the universe in the presence of a first order phase transition. A CP-asymmetry is found in the reflection coefficients of quarks hitting the phase boundary created during the electroweak transition. The problem is analyzed both in an academic zero temperatu

Alon E. Faraggi

I discuss the suppression of the lightest generation fermion mass terms in realistic superstring standard--like models in the free fermionic formulation. The suppression of the mass terms is a consequence of horizontal symmetries that arise due to the $Z_2\times Z_2$ orbifold compactification. In a specific model I investigate the possibility of resolving th

M. Drees, M. M. Nojiri

In this paper we discuss possible signatures for the production of scalar \stst\ (stoponium) bound states \sigst\ at hadron colliders, where \st\ is the lighter scalar top eigenstate. We first study the decay of \sigst; explicit expressions are given for all potentially important decay modes. If \st\ has unsuppressed two--body decays, they will always overwh

S. M. Bilenky, C. Giunti

The main features of the observables in the SNO and Super-Kamiokande solar neutrino experiments in the case of neutrino spin and/or spin-flavour precession in the magnetic field of the sun are discussed. It is shown without any model dependent assumption that in the case of Majorana transition magnetic moments the NC event rate $N^{\mathrm{NC}}$ does not dep

W. Bernreuther, A. Brandenburg

We investigate the possibilities of searching for non-standard CP violation in $pp\to t\bar{t}X$ at multiple TeV collision energies. A general kinematic analysis of the underlying partonic production processes $gg\to t\bar{t}$ and $q\bar{q}\to t\bar{t}$ in terms of their density matrices is given. We evaluate the CP-violating parts of these matrices in two-H

NRQCD collaboration

We present the first set of results for Charmonium Spectroscopy using Non-Relativistic QCD (NRQCD). For the NRQCD action the leading order spin-dependent and next to leading order spin-independent interactions have been included. Clear signals for the s and p hyperfine splittings have been observed as well as various orbital states.

Wolfgang Bock, James E. Hetrick, Jan Smit

A nonperturbative regularization of the Standard Model may have a superficially undesirable exact global U(1) symmetry corresponding to exact fermion number conservation. We argue that such a formulation can still have the desired physics of fermion nonconservation, i.e. fermion particle creation and annihilation by sphaleron transitions. We illustrate our r

Jeffrey E. Mandula, Michael C. Ogilvie

A computation of the Isgur-Wise universal form factor using a lattice implementation of the heavy quark effective theory is described, and the results of a lattice simulation are presented.

James E. Hetrick

Gauge fixing in general is incomplete, such that one solves some of the gauge constraints, quantizes, then imposes any residual gauge symmetries (Gribov copies) on the wavefunctions. While the Fadeev-Popov determinant keeps track of the local metric on this gauge fixed surface, the global topology of the reduced configuration space can be different depending

J. Smit, W. H. Tang

We compute the sphaleron transition rate in the 1+1 dimensional abelian Higgs model at finite temperature, by real time simulation using the classical canonical ensemble.

Nick Stanford

We present a new set of QCD codes in both message passing and data parallel versions. The message passing package used is PARMACS, although other packages may be used. Data parallel software is written in High Performance fortran, an emerging standard based on Fortran 90. Software engineering methods have been applied to a physics application to create thoro

Stephen Sharpe

Improved results for $B_K$ are discussed. Scaling corrections are argued to be of $O(a^2)$, leading to a reduction in the systematic error. For a kaon composed of degenerate quarks, the quenched result is ${\widehat{B}_K} = 0.825 \pm 0.027 \pm 0.023$.

Nadja S. Magalhaes, Carlos O. Escobar

We determine the transfer functions of two kinds of filters that can be used in the detection of continuous gravitational radiation. The first one optimizes the signal-to-noise ratio, and the second reproduces the wave with minimum error. We analyse the behaviour of these filters in connection with actual detection schemes.

G. L. Rcheulishvili

The solutions of generalized Killing equation have been obtained for line element with initial $t^2 \oplus so(3)$ symmetry. The coefficients of the metric $g$ corresponding to these vector fields are written down.

Janusz Karkowski, Piotr Koc, Zdobyslaw Swierczynski

We investigate axially symmetric asymptotically flat vacuum self-gravitating system. A class of initial data with apparent horizon was numerically constructed. The examined solutions satisfy the Penrose inequality. The prior analysis of a massive system and the present results suggest that either massive or sourcefree configurations fulfill the Penrose inequ

H. W. Lee, L. S. Levitov

We consider quantum fluctuations of current in a metallic loop induced by varying magnetic flux. The dependence of the fluctuations on the flux change $Φ$ contains a logarithmically divergent term periodic in $Φ$ with the period $Φ_0=hc/e$. The fluctuation is smallest near $Φ=nΦ_0$. The divergence is explained by a comparison with the orthogonality catastrop

S. Sil, S. N. Karmakar, R. K. Moitra

We discuss a very simple model of a 1-d disordered lattice, in which {\em all} the electronic eigenstates are extended. The nature of these states is examined from several viewpoints, and it is found that the eigenfunctions are not Bloch functions although they extend throughout the chain. Some typical wavefunctions are plotted. This problem originated in ou

Shoucheng Zhang, Daniel Arovas

We construct a nonlinear $σ$ model to describe a system of non-interacting electrons propagating in the presence of random magnetic flux. We find a term describing the long ranged logarithmic interaction between the topological density of the non-linear sigma model, and argue that this could give rise to a Kosterlitz-Thouless transition from the localized ph

Gongwen Peng, Hans J Herrmann

Density waves of granular flow in a pipe using lattice gas automata Gongwen Peng and Hans J. Herrmann HLRZ, KFA Jülich, D--52425 Jülich, Germany We use a lattice gas automaton modelling the formation of density waves of granular flow through a vertical pipe. It is found that both the dissipation and the roughness of walls of the pipe are essential to the eme

Mads Brandbyge, Per Hedegård

We suggest a simple model to describe the reversible field-induced transfer of a single Xe-atom in a scanning tunneling microscope, --- the Eigler-switch. The inelasticly tunneling electrons give rise to fluctuating forces on and damping of the Xe-atom resulting in an effective current dependent temperature. The rate of transfer is controlled by the well-kno

T. Schork, P. Fulde

Recently, it has been shown that the ground-state energy of a quantum many-body system can be written in terms of cumulants. In this paper we show that the energies of excited states can be expressed similarly. These representations are suitable for various approximation schemes, e.g., projection techniques. The explicit use of cumulants ensures size consist

Robert J. Nemiroff

The visual distortion effects visible to an observer traveling around and descending to the surface of an extremely compact star are described. Specifically, trips to a ``normal" neutron star, a black hole, and an ultracompact neutron star with extremely high surface gravity, are described. Concepts such as multiple imaging, red- and blue-shifting, conse

John N. Bahcall

The four operating solar neutrino experiments confirm the hypothesis that the energy source for solar luminosity is hydrogen fusion. However, the measured rate for each of the four solar neutrino experiments differs significantly (by factors of 2.0 to 3.5) from the corresponding theoretical prediction that is based upon the standard solar model and the simpl

M. Golterman, K. Jansen, D. Petcher, J. Vink

We have investigated a proposal to construct chiral gauge theories on the lattice using domain wall fermions. The model contains two opposite chirality zeromodes, which live on two domain walls. We couple only one of them to a gauge field, but find that mirror fermions which also couple to the gauge field always seem to exist.

S. Carlip, C. Teitelboim

The standard (Euclidean) action principle for the gravitational field implies that for spacetimes with black hole topology, the opening angle at the horizon and the horizon area are canonical conjugates. It is shown that the opening angle bears the same relation to the horizon area that the time separation bears to the mass at infinity. The dependence of the

Palash B. Pal

The equivalence theorem, between the longitudinal gauge bosons and the states eaten up by them in the process of symmetry breaking, is shown to be valid in a class of models where the details of dynamical symmetry breaking makes it obscure.