December 1994 arXiv papers — page 8

M. Schreckenberg, A. Schadschneider, K. Nagel, N. Ito

We investigate a probabilistic cellular automaton model which has been introduced recently. This model describes single-lane traffic flow on a ring and generalizes the asymmetric exclusion process models. We study the equilibrium properties and calculate the so-called fundamental diagrams (flow vs.\ density) for parallel dynamics. This is done numerically by

Stephen Cornell, Zbigniew Koza, Michel Droz

We consider the reaction zone that grows between separated regions of diffusing species $A$ and $B$ that react according to $mA+nB\to 0$, within the framework of the mean-fieldlike reaction-diffusion equations. For distances from the centre of the reaction zone much smaller than the diffusion length $X_D\equiv \sqrt{Dt}$, the particle density profiles are de

Yasumasa Hasegawa

The quantum Hall effect in the three-dimensional anisotropic tight-binding electrons is investigated in the field-induced spin density wave phases with a magnetic field tilted to any direction. The Hall conductivity, $σ_{xy}$ and $σ_{xz}$, are shown to be quantized as a function of the wave vector of FISDW, while $σ_{yz}$ stays zero, where $x$ is the most co

Lin-Yuan Chen, Nigel Goldenfeld

We present a numerical implementation of the renormalization group (RG) for partial differential equations, constructing similarity solutions and travelling waves. We show that for a large class of well-localized initial conditions, successive iterations of an appropriately defined discrete RG transformation in space and time will drive the system towards a

A. A. Thoul

We have developed an accurate, one-dimensional, spherically symmetric, Lagrangian hydrodynamics/gravity code, designed to study the effects of radiative cooling and photo-ionization on the formation of protogalaxies. We examine the ability of collapsing perturbations to cool within the age of the universe. In contrast to some studies based on order-of-magnit

Riccardo Giovanelli, Marco Scodeggio, Jose` M. Solanes, Martha P. Haynes

We report the serendipitous discovery of a large HI cloud with an associated HI mass of $6(\pm1.5)\times 10^9 h^{-2}$ M$_\odot$ and a heliocentric velocity 8800 \kms, located near the periphery of the cluster of galaxies Abell 2634. Its velocity field appears to be very quiescent, as no gradients in the peak velocity are seen over its extent of 143$ h^{-1}$

Craig J. Hogan

The comparison of cosmic abundances of the light elements with the density of baryonic stars and gas in the universe today provides a critical test of big bang theory and a powerful probe of the nature of dark matter. A new technique allows determination of cosmic deuterium abundances in quasar absorption clouds at large redshift, allowing a new test of big

Boqi Wang

We present the calculations of steady, spherical gas outflows from galaxies in an effort to understand the effects of the galaxy mass on the flow properties such as the size of the outflow regions, the efficiency of radiative cooling, and the fate of the cooled gas. We show that there exist no transonic flows but either subsonic or supersonic flows are obtai

J. L. Cervantes-Cota, H. Dehnen

We investigate the cosmological consequences of a theory of induced gravity in which the scalar field is identified with the Higgs field of the first symmetry breaking of a mi\-ni\-mal SU(5) GUT. The mass of the X-boson determines a great value for the coupling constant of gravity-particle physics. Because of this fact, a "slow" rollover dynamics for

Albert Stebbins, R. R. Caldwell

We study the effects of negative spatial curvature on the statistics of inhomogeneities in open cosmological models. In particular we examine the suppression of large-separation correlations in density and gravitational potential fluctuations and the resulting suppression of large-angle correlations in the anisotropy of the microwave background radiation. We

D. Edidin, W. Graham

We construct Euler and Stiefel-Whitney classes of vector bundles with quadratic form by analyzing the intersection theory of the associated quadric bundles. We also compute the Chow rings of quadric and isotropic flag bundles. Along the way, we prove a conjecture of Fulton on top Chern classes of maximal isotropic sub-bundles of an even rank quadratic vector

Rulin Xiu

We propose that a modified version of string-inspired supersymmetry breaking schemes in \cite{wit2} and \cite{ross} may make affine level one SU(5) and SO(10) string models with intermediate gauge symmetry breaking scale $M_{GUT}=10^{16}GeV$ possible; doublet-triplet problem can also be solved. In particular, we propose that some charged gauge background VEV

Emil Martinec

An interpretation of spacelike singularities in string theory uses target space duality to relate the collapsing Schwarzschild geometry near the singularity to an inflationary cosmology in dual variables. An appealing picture thus results whereby gravitational collapse seeds the formation of a new universe.

Abhay Ashtekar, Jerzy Lewandowski

In a quantum mechanical treatment of gauge theories (including general relativity), one is led to consider a certain completion, $\agb$, of the space $\ag$ of gauge equivalent connections. This space serves as the quantum configuration space, or, as the space of all Euclidean histories over which one must integrate in the quantum theory. $\agb$ is a very lar

Ludger Hannibal

It is proven that the usual quadratic general-covariant Lagrangian for the Dirac field leads to a symmetric, divergence-free energy-momentum tensor in the standard Riemannian framework of space-time without torsion, provided the tetrad field components are the only quantities related to gravitation that are varied independently.

B. Dutta, S. Willenbrock

Withdrawn. We thank J. T. Liu for bringing an error in the manuscript to our attention.

V. P. Gusynin, V. A. Miransky, I. A. Shovkovy

It is shown that in $3+1$ dimensions, a constant magnetic field is a catalyst of dynamical chiral symmetry breaking, leading to generating a fermion mass even at the weakest attractive interaction between fermions. The essence of this effect is the dimensional reduction $D \rightarrow D-2$ ($3+1 \rightarrow 1+1$) in the dynamics of fermion pairing in a magne

F. de Jong, K. Nakayama, T. -S. H. Lee

The proton-proton bremsstrahlung is investigated within a coupled-channel model with the $Δ$ degree of freedom. The model is consistent with the $NN$ scattering up to 1 GeV and the $γNΔ$ vertex determined in the study of pion photoproduction reactions. It is found that the $Δ$ excitation can significantly improve the agreements with the $pp \rightarrow ppγ$

L. Mornas, U. Ornik

The influence of the dissipative terms on the conditions of formation and the characteristic parameters of shock waves in relativistic nuclear collisions is investigated for three types of equation of state (non linear QHD-1, resonance gas and lattice QCD). Energy and velocity profiles are obtained in a one-dimensional model; the duration of the shock phase

E. Bylaska, S. Khon, S. Baden, A. Edelman

A new method of solution to the local spin density approximation to the electronic Schr\"{o}dinger equation is presented. The method is based on an efficient, parallel, adaptive multigrid eigenvalue solver. It is shown that adaptivity is both necessary and sufficient to accurately solve the eigenvalue problem near the singularities at the atomic centers. Whi

E. Pehlke, M. Scheffler

While the small sticking coefficient for molecular hydrogen on the Si(001) surface apparently requires a large energy barrier of adsorption, no such barrier is observed in desorption experiments. We have calculated the potential-energy surface of an H_2 molecule in front of a Si(001) surface. If we relax the Si substrate, we find an optimum desorption path w

Mikhail Lyubich, Yair Minsky

We suggest a way to associate to a rational map of the Riemann sphere a three dimensional object called a hyperbolic orbifold 3-lamination. The relation of this object to the map is analogous to the relation of a hyperbolic 3-manifold to a Kleinian group. In order to construct the 3-lamination we analyze the natural extension of a rational map and the comple

P. Ramadevi, T. R. Govindarajan, R. K. Kaul

We show that any of the new knot invariants obtained from Chern-Simons theory based on an arbitrary non-abelian gauge group do not distinguish isotopically inequivalent mutant knots and links. In an attempt to distinguish these knots and links, we study Murakami (symmetrized version) $r$-strand composite braids. Salient features of the theory of such composi

D. Korotkin, H. Nicolai

It is shown that the vacuum Einstein equations for an arbitrary stationary axisymmetric space-time can be completely separated by re-formulating the Ernst equation and its associated linear system in terms of a non-autonomous Schlesinger-type dynamical system. The conformal factor of the metric coincides (up to some explicitly computable factor) with the $τ$

Gabriel Lopes Cardoso, Dieter Lust, Thomas Mohaupt

We discuss recent results on orbifold compactifications with (0,2) world sheet supersymmetry and continuous Wilson lines, emphasizing the role of modular symmetries. (This work is a contribution to the proceedings of the joint US Polish Workshop on Physics from the Planck scale to the Electro-Weak scale, Warsaw, 21.9. - 24.9.1994)

J. Mourad, H. Sazdjian

It is shown that, by an appropriate modification of the structure of the interaction potential, the Breit equation can be incorporated into a set of two compatible manifestly covariant wave equations, derived from the general rules of Constraint Theory. The complementary equation to the covariant Breit type equation determines the evolution law in the relati

Gautam Bhattacharyya, Debajyoti Choudhury, K. Sridhar

In the Standard Model (SM), dilepton production in hadron--hadron collisions proceeds through the conventional Drell--Yan mechanism $q \bar{q} \rightarrow l^+ l^-$ with the exchange of a gauge boson. Some extensions of the SM contain a quark--lepton contact interaction {\it via} a $q l ϕ$ Yukawa coupling, where $ϕ$ is a scalar. Theories with scalar leptoquar

M. Vysotsky, ITEP, Moscow, Russia

We present a simple method for considering radiative corrections. Precision data are well described by an adequate Born approximation and only the first evidence for deviations from the tree level formulas and the presence of the loop effects emerge.

A. Ali Khan, S. Collins, C. T. H. Davies, D. Henty

Preliminary results on spectrum and decay constant of $B$ mesons from a quenched simulation at $β= 6.0$ on an $16^3\times48$ lattice are discussed. The heavy quark has been implemented using both an NRQCD and the static formulation, the light one with a clover improved Wilson formulation. Both the NRQCD Hamiltonian and the heavy-light current consistently in

A. Ali Khan, I. Barbour

The lowest zeros of the lattice partition function for non-compact QED are found in the complex fermion mass plane on $6^4$, $8^4$ and $10^4$ lattices at intermediate values of the coupling. The scaling of the low lying zeros with lattice size is analysed.

Philippe de Forcrand, James E. Hetrick

We study gauge fixing via the standard local extremization algorithm for 2-dimensional $U(1)$. On a lattice with spherical topology $S^2$ where all copies are lattice artifacts, we find that the number of these 'Gribov' copies diverges in the continuum limit. On a torus, we show that lattice artifacts can lead to the wrong evaluation of the gauge-inv

Robert G. Edwards, Khalil Bitar, Urs M. Heller, A. D. Kennedy

We test the cooling algorithm with gluonic and staggered hadronic spectroscopy on $SU(3)$ gauge field configurations generated with two flavors of staggered dynamical fermions. We find cooling is not reliable as the basis for improved hadronic operators. We also find that performing cooling sweeps to reveal more clearly the topological properties of the gaug

J. Sexton, A. Vaccarino, D. Weingarten

We evaluate the coupling constant for the lightest scalar glueball to decay to pseudoscalar meson pairs. The calculation is done in the valence approximation on a $16^3 \times 24$ lattice at $β= 5.70$ for two different values of pseudoscalar meson mass.

Artan Borici, Philippe de Forcrand

We compare the quenched hadron spectrum on blocked and unblocked lattices for the Wilson quark action, the clover action and the tadpole-improved clover action. The latter gives a spectrum markedly closer to the original one, even though the cutoff is 1/a ~ 500 Mev.

Grigorios I. Poulis, Howard D. Trottier

We calculate the potential between adjoint sources in $SU(2)$ pure gauge theory in three dimensions. We investigate whether the potential saturates at large separations due to the creation of a pair of gluelumps, colour-singlet states formed when glue binds to an adjoint source.

R. Enomoto

In CP violation measurements in asymmetric B-factory experiments, a determination of the B flavor of the neutral B mesons is necessary. A new method to this purpose using only three vectors of charged particles has been developed. This method (weighted charge method) does not require either lepton identification or charged-kaon identification. The tagging ef

Eric Poisson, Misao Sasaki

A particle of mass $μ$ moves on a circular orbit of a nonrotating black hole of mass $M$. Under the restrictions $μ/M \ll 1$ and $v \ll 1$, where $v$ is the orbital velocity, we consider the gravitational waves emitted by such a binary system. We calculate $\dot{E}$, the rate at which the gravitational waves remove energy from the system. The total energy lo

Misao Sasaki, Takahiro Tanaka, Kazuhiro Yamamoto

Motivated by recent studies of the one-bubble inflationary universe scenario that predicts a low density, negative curvature universe, we investigate the Euclidean vacuum mode functions of a scalar field in a spatially open chart of de Sitter space which is foliated by hyperbolic time slices. When we consider the possibility of an open inflationary universe,

T. Damour

The confrontation between Einstein's theory of gravitation and experiment is summarized. Although all current experimental data are compatible with general relativity, the importance of pursuing the quest for possible deviations from Einstein's theory is emphasized.

Carson C. Chow, Terence Hwa

Spatiotemporal chaos (STC) exhibited by the Kuramoto-Sivashinsky (KS) equation is investigated analytically and numerically. An effective stochastic equation belonging to the KPZ universality class is constructed by incorporating the chaotic dynamics of the small KS system in a coarse-graining procedure. The bare parameters of the effective theory are comput

M. C. W. van Rossum, Th. M. Nieuwenhuizen, R. Vlaming

The optical conductance of a multiple scattering medium is the total transmitted light of a diffuse incoming beam. This quantity, very analogous to the electronic conductance, exhibits universal conductance fluctuations. We perform a detailed diagrammatic analysis of these fluctuations. With a Kadanoff-Baym technique all the leading diagrams are systematical

R. V. E. Lovelace, M. M. Romanova, G. S. Bisnovatyi-Kogan

An investigation is made of disk accretion of matter onto a rotating star with an aligned dipole magnetic field. A new aspect of this work is that when the angular velocity of the star and disk differ substantially we argue that the $\bf B$ field linking the star and disk rapidly inflates to give regions of open field lines extending from the polar caps of t

F. la Franca, A. Franceschini, S. Cristiani, R. Vio

The issue of the X-ray to optical luminosity relationship ($L_o-L_x$) is addressed for both optically and X-ray selected quasar samples. We have applied a generalized regression algorithm for the case of samples involving censored data, with errors on both the dependent and the independent variable. Contrary to some previous results, we find that such relati

The AMANDA collaboration

The optical properties of the ice at the geographical South Pole have been investigated at depths between 0.8 and 1 kilometers. The absorption and scattering lengths of visible light ($\sim$515 nm) have been measured {\it in situ } using the laser calibration setup of the AMANDA neutrino detector. The ice is intrinsically extremely transparent. The measured

O. Lahav, A. Naim, R. J. Buta, H. G. Corwin

Quantitative morphological classification of galaxies is important for understanding the origin of type frequency and correlations with environment. But galaxy morphological classification is still mainly done visually by dedicated individuals, in the spirit of Hubble's original scheme, and its modifications. The rapid increase in data on galaxy images at lo

S. J. Litchfield, J. A. Stevens, E. I. Robson, W. K. Gear

The infrared through millimetre light curve of 3C 279 is investigated for the period of 1986 until mid-1994, during which time several flares were observed. A quiescent spectrum (identified with emission from an underlying jet) is presented. Both the near-IR and 375-150 GHz regimes are shown to be well described by power laws, with no evidence for any therma

Martin Klein-Kreisler, Manuel Torres

We investigate the properties of quantum electrodynamics $(QED_3)$ in two spatial dimensions at finite temperature and density. The static as well as the dynamical properties of the planar plasma are calculated using the real time formalism of quantum field theory. It is shown, that due to the presence of the parity breaking Chern-Simons term, the propagatin

H. C. Baehr, A. Dimakis, F. Müller-Hoissen

A differential calculus on an associative algebra A is an algebraic analogue of the calculus of differential forms on a smooth manifold. It supplies A with a structure on which dynamics and field theory can be formulated to some extent in very much the same way we are used to from the geometrical arena underlying classical physical theories and models. In pr

Yoav Peleg, Alan Steif

The collapse of thin dust shells in 2+1 dimensional gravity with and without a cosmological constant in analyzed. A critical value of the shell's mass as a function of its radius and position is derived. For $\Lambda < 0$, a naked singularity or black hole forms depending on whether the shell's mass is below or just above this value. The solution space is di

Konstadinos Sfetsos

Starting with exact solutions to string theory on curved spacetimes we obtain deformations that represent gravitational shock waves. These may exist in the presence or absence of sources. Sources are effectively induced by a tachyon field that randomly fluctuates around a zero condensate value. It is shown that at the level of the underlying conformal field

C. W. Kim, A. Sinibaldi, J. Song

Based on the observed increase of $Ω_0$ as a function of cosmic scale, the Robertson--Walker metric and the Einstein equation are generalized so that $ Ω_0$, $H_0$, and the age of the Universe, $t_0$, all become functions of cosmic scales at which we observe them. The calculated local (within our galaxy) age of the Universe is about 18 Gyr, consistent with t

Naoshi Sugiyama

Cosmic microwave background (CMB) anisotropies and density fluctuations are calculated for flat cold dark matter (CDM) models with a wide range of parameters, i.e., $\Omega_0, h$ and $\Omega_B$ for both standard recombination and various epochs of reionization. Tables of the power spectrum of CMB anisotropies in the form of $C_\ell$'s as a function of $\ell$

Tchavdar D. Palev

The Lie algebra $so(2n+1)$ and the Lie superalgebra $osp(1/2n)$ are quantized in terms of $3n$ generators, called preoscillator generators. Apart from $n$ &#34;Cartan&#34; elements the preoscillator generators are deformed para-Fermi operators in the case of $so(2n+1)$ and deformed para-Bose operators in the case of $osp(1/2n)$. The corresponding deformed un

P. Podles, S. L. Woronowicz

Using the general theory of [10] ( hep-th 9412058 ), quantum Poincaré groups (without dilatations) are described and investigated. The description contains a set of numerical parameters which satisfy certain polynomial equations. For most cases we solve them and give the classification of quantum Poincaré groups. Each of them corresponds to exactly one quant

P. Podles, S. L. Woronowicz

We investigate inhomogeneous quantum groups G built from a quantum group H and translations. The corresponding commutation relations contain inhomogeneous terms. Under certain conditions (which are satisfied in our study of quantum Poincare groups [12]) we prove that our construction has correct `size&#39;, find the R-matrices and the analogues of Minkowski

S. W. Huang, K. Tsushima, A Faessler, E. Lehmann

In a resonance model the reactions pi N -> Y K and pi Delta -> Y K are studied. For the reactions pi N -> Lambda K and pi Delta -> Lambda K, the resonances N(1650)(J^P=1/2^-), N(1710)(1/2^+) and N(1720)(3/2^+) are included as intermediate states. For the reactions pi N -> Sigma K, the resonances N(1710)(1/2^+), N(1720)(3/2^+) and Delta(1920)(3/2^+) are consi

Hua-lin Shi, Bao-qiu Chen, Zhong-yu Ma

The self-energy of the Dirac Brueckner-Hartree-Fock calculation in nuclear matter is parametrized by introducing density-dependent coupling constants of isoscalar mesons in the relativistic Hartree-Fock (RHF) approach where isoscalar meson $σ$ , $ω$ and isovector meson $π$, $ρ$ contributions are included. The RHF calculations with density dependent coupling

Erik Koelink

For a two parameter family of Askey-Wilson polynomials, that can be regarded as basic analogues of the Legendre polynomials, an addition formula is derived. The addition formula is a two-parameter extension of Koornwinder&#39;s addition formula for the little $q$-Legendre polynomials. A corresponding product formula is derived. As the base tends to one, the

K. Kirsten, Yu. Kubyshin

In previous articles it was demonstrated that the total cross section of the scattering of two light particles (zero modes of the Kaluza-Klein tower) in the six-dimensional $λϕ^{4}$ model differs significantly from the cross section of the same process in the conventional $λϕ^{4}$ theory in four space-time dimensions even for the energies below the threshold

E. S. Fraga, C. A. A. De Carvalho

We present a study of the decay of metastable states of a scalar field via thermal activation, in the presence of a finite density of fermions. The process we consider is the nucleation of ``{\it droplets}&#39;&#39; of true vacuum inside the false one. We analyze a one-dimensional system of interacting bosons and fermions, considering the latter at finite te

V. V. Dodonov, S. Yu. Kalmykov, V. I. Man&#39;ko

We study the Photon statistics in the superpositions of coherent states $|α\rangle$ and $|α^*\rangle$ named ``Schrödinger real and imaginary cat states&#39;&#39;. The oscillatory character of photon distribution function (PDF) emerging due to the quantum interference between the two components is shown, and the phenomenon of the quadrature squeezing is obser

B. A. Faizullaev, M. M. Musakhanov

On the basis of a new approach proposed in our previous work we develope a formalism for calculating of the effective action for some models containing fermion fields. This method allows us to calculate the fermionic part of the effective action (up to two-loop level) properly. The two-loop contribution to the effective potential for the Nambu-Jona-Lasinio m

V. A. Smirnov

General prescriptions of differential renormalization are presented. It is shown that renormalization group functions are straightforwardly expressed through some constants that naturally arise within this approach. The status of the action principle in the framework of differential renormalization is discussed.

V. A. Smirnov

General results on asymptotic expansions of Feynman diagrams in momenta and/or masses are reviewed. It is shown how they are applied for calculation of massive diagrams.

Timothy J. Hollowood, J. Luis Miramontes, Q-Han Park

Massive integrable field theories in $1+1$ dimensions are defined at the Lagrangian level, whose classical equations of motion are related to the ``non-abelian&#39;&#39; Toda field equations. They can be thought of as generalizations of the sine-Gordon and complex sine-Gordon theories. The fields of the theories take values in a non-abelian Lie group and it

E. Elizalde, A. G. Jacksenaev, S. D. Odintsov, I. L. Shapiro

The most general version of a renormalizable $d=4$ theory corresponding to a dimensionless higher-derivative scalar field model in curved spacetime is explored. The classical action of the theory contains $12$ independent functions, which are the generalized coupling constants of the theory. We calculate the one-loop beta functions and then consider the cond

S. H. Park

I investigate the effects of the Chern-Simons coupling on high-energy behavior in $2+1$ dimensional U(1) gauged $η(ϕ^\daggerϕ)^3$ theory with a Chern-Simons term. The effective potential and the $β$ function for $η$ are calculated to the next-to-leading order of the $1/N$ expansion as functions of $θ$ (the Chern-Simons coupling). For all $θ$, the theory is f

D. de Florian, R. Sassot

The complete next to leading logarithmic (${\cal O}(α_{s})$) corrections to the spin dependent weak deep inelastic structure functions $g_{1},g_{3}$ and $g_{4}$, are calculated using dimensional regularization within the HVBM method. Analysing the quark and gluon initiated contributions to these corrections for different values for the quark masses, a consis

Darwin Chang, Xiao-Gang He, Sandip Pakvasa

We consider CP violation due to left-right mixing in a class of Left-Right symmetric models and show that it leads to observable effects in hyperon decays. For S-wave, the contribution to CP violating asymmetry A of the polarization in hyperon and anti-hyperon decays is proportional to $ε&#39;/ε$. While the tree level L-R operators contribution is constraine

Thomas D. Cohen, Wojciech Broniowski

We analyze the chiral limit in dense isospin-asymmetric nuclear matter. It is shown that the pseudo-Goldstone modes in this system are qualitatively different from the case of isospin-symmetric matter.

M. Sakuda, Y. Kurihara

If the neutrino has a finite mass and a magnetic moment it would produce transition radiation when crossing the interface between two media. We found that the probability of transition radiation is larger by an order of magnitude using the quantum theory than that recently reported by one of us using classical electrodynamics, and that the energy spectrum of

Weonjong Lee, Markus Klomfass

It has been known for some time that there are two methods to calculate $ B_K $ with staggered fermions: one is the two spin trace formalism and the other is the one spin trace formalism. Until now, the two spin trace formalism has been exclusively used for weak matrix element calculations with staggered fermions. Here, the one spin trace formalism to calcul

T. Blum, C. DeTar, Urs M. Heller, Leo Karkkainen

We study the thermal phase diagram of pure SU(3) lattice gauge theory with fundamental and adjoint couplings. We improve previous estimates of the position of the bulk transition line and determine the thermal deconfinement transition lines for $N_t=2,4,6,$ and 8. The endpoint of the bulk transition line $(β_f, β_a)=(4.00(7), 2.06(8))$ improves upon earlier

W. Beirl, B. A. Berg, B. Krishnan, H. Markum

We present investigations of the potential between static charges from a simulation of quantum gravity coupled to an SU(2) gauge field on $6^{3}\times 4$ and $8^{3}\times 4$ simplicial lattices. In the well-defined phase of the gravity sector where geometrical expectation values are stable, we study the correlations of Polyakov loops and extract the correspo

Harald F. Muller, Christoph Schmid

We analyze the non--Gaussian primordial fluctuations which are inescapably contributed by scalar fields $Φ$ with vanishing expectation values, $\langleΦ\rangle=0$, present during inflation in addition to the inflaton field. For simplicity we take $Φ$ to be non--interacting and minimally coupled to gravity. $Φ$ is a Gaussian variable, but the energy density f

Harald F. Muller, Christoph Schmid

We analyze the energy density fluctuations contributed by scalar fields $Φ$ with vanishing expectation values, $\langleΦ\rangle=0$, which are present in addition to the inflaton field. For simplicity we take $Φ$ to be non--interacting and minimally coupled to gravity. We use normal ordering to define the renormalized energy density operator $ρ$, and we show

Hans-Juergen Matschull

A new representation for canonical gravity and supergravity is presented, which combines advantages of Ashtekar&#39;s and the Wheeler~DeWitt representation: it has a nice geometric structure and the singular metric problem is absent. A formal state functional can be given, which has some typical features of a vacuum state in quantum field theory. It can be c

K. A. Park, Robert Joynt

The phase diagram of the unconventional superconductor UPt$_3$ is explained under the long-standing hypothesis that the pair wavefunction belongs to the $E_{1g}$ representation of the point group. The main objection to this theory has been that it disagrees with the experimental phase diagram when a field is applied along the c-axis. By a careful analysis of

T. Garel, Mehran Kardar, H. Orland

We study the adsorption of polymer chains on a fluctuating surface. Physical examples are provided by polymer adsorption at the rough interface between two non-miscible liquids, or on a membrane. In a mean-field approach, we find that the self--avoiding chains undergo an adsorption transition, accompanied by a stiffening of the fluctuating surface. In partic

D. F. B. ten Haaf, H. J. M. van Bemmel, J. M. J. van Leeuwen, W. van Saarloos

We justify a recently proposed prescription for performing Green Function Monte Carlo calculations on systems of lattice fermions, by which one is able to avoid the sign problem. We generalize the prescription such that it can also be used for problems with hopping terms of different signs. We prove that the effective Hamiltonian, used in this method, leads

H. J. Schulz

The low--energy excited states of a system of interacting one--dimensional fermions in a conducting state are collective charge and spin density oscillations. The unusual physical properties of such a system (called ``Luttinger liquid&#39;&#39;) are characterized by the velocities $u_ρ$ and $u_σ$ of the charge and spin excitations, as well as by a parameter

Stéphane OUVRY, Division de Physique Théorique, IPN, Orsay Fr-91406

A general introduction to the anyon model (braid group, Chern-Simons Lagrangian and Aharonov-Bohm Hamiltonian formulations) is given. A review follows on exact results and possible ways of getting additional information, as mean field approach, perturbation theory, and projection on the lowest Landau level of an external magnetic field. To be published in Me

Giorgio Parisi

We will review some of the theoretical progresses that have been recently done in the study of slow dynamics of glassy systems: the general techniques used for studying the dynamics in the mean field approximation and the emergence of a pure dynamical transition in some of these systems. We show how the results obtained for a random Hamiltonian may be also a

Steven A. Henck, Martin A. Mason, Wen - Bin Yan, Kevin K. Lehmann

Microwave detected, microwave-optical double resonance was used to record the A state electronic spectrum of NH3, NH2D, and NHD2 with both vibrational and rotational resolution. To investigate ND3 with the same resolution as we had with our hydrogen containing isotopomers, a strip-line cell was constructed allowing the simultaneous passage of radio-frequency

Rupert Croft, George Efstathiou

We investigate the feasibility of carrying out likelihood analysis on the velocities of galaxy clusters to determine power spectrum parameters. Using N-body simulations of cosmological density fields we show that the velocity field traced by clusters is highly non-linear on small scales (r < 10 h^-1 Mpc), mostly due to strong infall into superclusters. The t

W. N. Brandt, Ph. Podsiadlowski

We systematically investigate the effects of high supernova kick velocities on the orbital parameters of post-supernova neutron-star binaries. Using Monte- Carlo simulations, we determine the post-supernova distributions of orbital parameters for progeneitors of HMXBs and LMXBs. With the recent distribution of pulsar birth velocities by Lyne & Lorimer (1994)

I. -A. Yadigaroglu, Roger W. Romani

We compute the variation of the beaming fraction with the efficiency of high energy gamma-ray production in the outer gap pulsar model of Romani and Yadigaroglu. This allows us to correct the fluxes observed for pulsars in the EGRET band and to derive a simple estimate of the variation of efficiency with age. Integration of this model over the population of

P. M. Lubin

The Cosmic Background Radiation gives us one of the few probes into the density perturbations in the early universe that should later lead to the formation of structure we now observe. Recent advances in degree scale anisotropy measurements have allowed us to begin critically testing cosmological models. Combined with the larger scale measurements from COBE

J. Gundersen, M. Lim, J. Staren, C. Wuensche

We present results from 2 observations of the CMB performed from the South Pole during the 93-94 austral summer. Each observation employed a 3$^{\circ}$ peak to peak sinusoidal, single difference chop and consisted of a $20^{\circ}\times 1^{\circ}$ strip on the sky near our SP91 observations. The first observation used a Q-band receiver which operates in 3 b

R. Jeffrey Wilkes

The field of high energy neutrino astrophysics is entering an exciting new phase as two new large-scale observatories prepare to come on line. Both DUMAND (Deep Underwater Muon and Neutrino Detector) and AMANDA (Antarctic Muon and Neutrino Detector) had major deployment efforts in 12/93--1/94. Results were mixed, with both projects making substantial progres

Luca Barbieri-Viale

We are showing that the Deligne--Beilinson cohomology sheaves ${\cal H}^{q+1}({\bf Z}(q)_{\cal D})$ are torsion free by assuming Kato&#39;s conjectures hold true for function fields. This result is `effective&#39; for $q=2$; in this case, by dealing with `arithmetic properties&#39; of the presheaves of mixed Hodge structures defined by singular cohomology, w

A. P. Balachandran, L. Chandar, Arshad Momen

We show in the context of Einstein gravity that the removal of a spatial region leads to the appearance of an infinite set of observables and their associated edge states localized at its boundary. Such a boundary occurs in certain approaches to the physics of black holes like the one based on the membrane paradigm. The edge states can contribute to black ho

Galin Georgiev

This is the first of a series of papers studying combinatorial (with no ``subtractions&#39;&#39;) bases and characters of standard modules for affine Lie algebras, as well as various subspaces and ``coset spaces&#39;&#39; of these modules. In part I we consider certain standard modules for the affine Lie algebra $\ga,\;\g := sl(n+1,\C),\;n\geq 1,$ at any pos

Michael Flohr

We study the possible phase transitions between (2+1)-dimensional abelian Chern-Simons theories. We show that they may be described by non-unitary rational conformal field theories with c_eff = 1. As an example we choose the fractional quantum Hall effect and derive all its main features from the discrete fractal structure of the moduli space of these non-un

Christof Schmidhuber

The renormalization group flow in two--dimensional field theories is modified if they are coupled to gravity. Beta function coefficients are changed, the $c$--theorem is no longer strictly valid, and flows from fixed points with central charge $c>25$ to fixed points with $c<25$ are forbidden. This is discussed in general and at two examples, the Kosterlitz--

Dirk Kreimer

We investigate to what extent renormalization can be understood as an algebraic manipulation on concatenated one-loop integrals. We find that the resulting algebra indicates a useful connection to knot theory.

Apoorva Patel

The strong coupling lattice QCD solution \cite{APtifr} for the Isgur-Wise functions, parametrising the semileptonic decay form factors of hadrons containing a single heavy quark, is reviewed. Several useful features connected with the result are pointed out.

N. Read, S. Sachdev, J. Ye

We consider quantum rotors or Ising spins in a transverse field on a $d$-dimensional lattice, with random, frustrating, short-range, exchange interactions. The quantum dynamics are associated with a finite moment of inertia for the rotors, and with the transverse field for the Ising spins. For a suitable distribution of exchange constants, these models displ

M. Oleszczuk

I consider the dilute monopole gas expansion of the three dimensional Yang-Mills-Higgs system in the symmetry broken phase. The functional determinants which occur in such an expansion are computed in the heat kernel approximation for an arbitrary $SU(N)$ gauge group. Explicit expressions for the gauge boson mass in the unbroken gauge sector and the string t

B. P. Dolan

It is demonstrated that decimation of the one dimensional Ising model, with periodic boundary conditions, results in a non-linear renormalisation transformation for the couplings which can lead to chaotic behaviour when the couplings are complex. The recursion relation for the couplings under decimation is equivalent to the logistic map, or more generally th