March 1995 arXiv papers — page 2

A. Yu. Alekseev, V. Schomerus

Recently we suggested a new quantum algebra, the moduli algebra, which was conjectured to be a quantum algebra of observables of the Hamiltonian Chern Simons theory. This algebra provides the quantization of the algebra of functions on the moduli space of flat connections on a 2-dimensional surface. In this paper we classify unitary representations of this n

Afsar Abbas

A lot of theoretical ideas have been floated to explain the so called cold fusion phenomenon. I look at a large subset of these and study further physical implications of the concepts involved. I suggest that these can be tested by other independent physical means. Because of the significance of these the experimentalists are urged to look for these signatur

Michael J. Love, Henri J. F. Jansen

The evaluation of Coulomb forces is a difficult task. The summations that are involved converge only conditionally and care has to be taken in selecting the appropriate procedure to define the limits. The Ewald method is a standard method for obtaining Coulomb forces, but this method is rather slow, since it depends on the square of the number of atoms in a

Alejandro Adem, R. James Milgram

In this paper we show that the mod 2 cohomology ring of any finite simple group of rank 3 or less (at the prime 2) must be Cohen-Macaulay.

Alejandro Adem, Nadim Naffah

In this paper we compute the integral cohomology of the discrete groups SL(2,Z[1/p]), where p is any prime.

Alejandro Adem, R. James Milgram

In this paper we compute the mod 2 cohomology of the McLaughlin group, which is one of the sporadic simple groups.

L. Dolan, S. Horvath

For the closed superstring, spin fields and bi-spinor states are defined directly in four spacetime dimensions. Explicit operator product expansions are given, including those for the internal superconformal field theory, which are consistent with locality and BRST invariance for the string vertices. The most general BRST picture changing for these fields is

Adel Bilal, Ian. I. Kogan

After giving a pedagogical review of the chiral gauge approach to 2D gravity, with particular emphasis on the derivation of the gravitational Ward identities, we discuss in some detail the interpretation of matter correlation functions coupled to gravity in chiral gauge. We argue that in chiral gauge no {\it explicit} gravitational dressing factor, analogue

Paul S. Aspinwall, David R. Morrison, Mark Gross

We study a topological obstruction of a very stringy nature concerned with deforming the target space of an $N=2$ non-linear \sm. This target space has a singularity which may be smoothed away according to the conventional rules of geometry but when one studies the associated conformal field theory one sees that such a deformation is not possible without a d

G. Pradisi, A. Sagnotti, Ya. S. Stanev

We show how to generalize the $SU(2)$ WZW models to allow for open and unoriented sectors. The construction exhibits some novel patterns of Chan-Paton charge assignments and projected spectra that reflect the underlying current algebra.

Parthasarathi Majumdar

Point particle scattering at Planckian centre-of-mass (cm) energies and low fixed momentum transfers, occurring due both to electromagnetic and gravitational interactions, is surveyed, with particular emphasis on the novel features occurring in electromagnetic charge-monopole scattering. The issue of possible mixing of the shock waves occurring due to both k

M. L. Mangano, A. Petrelli

We present a global fit of current available experimental results on $χ_c$ decays within next-to-leading-order perturbative QCD. The quality and reduced errors of recent data improve the agreement between theory and experiment.

J. Binnewies, B. A. Kniehl, G. Kramer

We present new sets of fragmentation functions for charged pions and kaons, both at leading and next-to-leading order. They are fitted to data on inclusive charged-hadron production in $e^+e^-$ annihilation taken by TPC at PEP ($\sqrt s=29$~GeV) and to similar data by ALEPH at LEP, who discriminated between events with charm, bottom, and light- flavour fragm

M. Hayakawa, T. Kinoshita, A. I. Sanda

The hadronic light-by-light scattering contribution to muon $g-2$ is examined using low energy effective theories of QCD, the Nambu-Jona-Lasinio model and hidden local chiral symmetry, as guides. Our result is $- 36 \times 10^{-11}$ with an uncertainty of $\pm 16 \times 10^{-11}$, which includes our best estimate of model dependence. This is within the expec

M. Jezabek

Polarization studies for heavy quarks can lead to important tests of the Standard Model. Top quark pair production in $e^+e^-$ annihilation is considered near energy threshold. It is shown that for longitudinally polarized electrons the produced top quarks and antiquarks are highly polarized. Dynamical effects originating from strong interactions in the $t-\

Samuel W. MacDowell, Ola Törnkvist

Vortex configurations in the electroweak gauge theory are investigated. Two gauge-inequivalent solutions of the field equations, the Z and W vortices, have previously been found. They correspond to embeddings of the abelian Nielsen-Olesen vortex solution into a U(1) subgroup of SU(2)xU(1). It is shown here that any electroweak vortex solution can be mapped i

Cayetano Di Bartolo, Rodolfo Gambini, Jorge Griego, Jorge Pullin

This article reviews the status of several solutions to all the constraints of quantum gravity that have been proposed in terms of loops and extended loops. We discuss pitfalls of several of the results and in particular discuss the issues of covariance and regularization of the constraints in terms of extended loops. We also propose a formalism for ``thicke

M. C. Bento, O. Bertolami

We study the effect of higher-curvature terms in the string low-energy effective actions on the cosmological solutions of the theory, up to corrections quartic in the curvatures, for the bosonic and heterotic strings as well as the type II superstring. We find that cosmological solutions exist for all string types but they always disappear when the dilaton f

Nenad Manojlovic, Guillermo A. Mena Marugan

We apply the algebraic quantization programme proposed by Ashtekar to the analysis of the Belinski\vı-Zakharov classical spacetimes, obtained from the Kasner metrics by means of a generalized soliton transformation. When the solitonic parameters associated with this transformation are frozen, the resulting Belinski\vı-Zakharov metrics provide the set of clas

Jeeva Anandan

An important limitation is shown in the analogy between the Aharonov-Bohm effect and the parallel transport on a cone. It illustrates a basic difference between gravity and gauge fields due to the existence of the solder form for the space-time geometry. This difference is further shown by the observability of the gravitational phase for open paths. This rei

Andras Csordas, Robert Graham

In this lecture supersymmetric minisuperspace models of any Bianchi type within class A of the classification of Ellis and McCallum are considered. The algebra of the supersymmetry generators, the Lorentz generators, the diffeomorphism generators and the Hamiltonian generator is determined explicitely and found to close. Different from earlier work it is est

Zlatko Tesanovic

Fluctuation behavior of high temperature superconductors in high magnetic field is studied within the Ginzburg-Landau theory. Landau level degeneracy of Cooper pairs enhances fluctuations which destroy the familiar Abrikosov vortex lattice for D=2,3. Instead, a charge-density wave of Cooper pairs (SCDW) is the new low-temperature phase of the theory. SCDW ha

T. Yildirim, A. B. Harris, Amnon Aharony, O. Entin-Wohlman

This paper contains the details of Phys. Rev. Lett. 73, 2919 (1994) and, to a lesser extent, Phys. Rev. Lett. 72, 3710 (1994). We treat a Hubbard model which includes all the 3d states of the Cu ions and the 2p states of the O ions. We also include spin-orbit interactions, hopping between ground and excited crystal field states of the Cu ions, and rather gen

M. P. López-Sancho, F. Guinea, J. A. Vergés, E. Louis

The low energy spin and charge excitations in the 2D Hubbard model near half filling are analyzed. The RPA spectra derived from inhomoheneous mean field textures are analyzed. Spin excitations show a commensurate peak at half filling, incommensurate peaks near half filling, and a broad background typical of a dilute Fermi liquid away from half filling. Charg

Tao Xiang

Localization lengths of superconducting quasiparticles $λ_s$ are evaluated and compared with the corresponding normal state values $λ_n$ in one and two dimensional lattices. The effect of superconducting correlation on the localization of quasiparticles is generally stronger in an off-site pairing state than in an on-site pairing state. The modification of s

Yinlong Sun, George Kirczenow, Andrew. S. Sachrajda, Yan Feng

We present a theoretical model of split-gate quantum wires that are fabricated from GaAs-AlGaAs heterostructures. The model is built on the physical properties of donors and of semiconductor surfaces, and considerations of equilibrium in such systems. Based on the features of this model, we have studied different ionization regimes of quantum wires, provided

Eyal Maoz

There is now dynamical evidence for massive dark objects at the center of several galaxies, but suggestions that these are supermassive black holes are based only on indirect astrophysical arguments. The recent unprecedented measurement of the rotation curve of maser emission sources at the center of NGC 4258, and the remarkable discovery that it is Kepleria

Neta A. Bahcall

The Sloan Digital Sky Survey (SDSS) will provide a complete imaging and spectroscopic survey of the high-latitude northern sky. The 2D survey will image the sky in five colors and will contain nearly 5 x 107 galaxies to g ~ 23m. The spectroscopic survey will obtain spectra of the brightest 106 galaxies, 105 quasars, and 103.5 rich clusters of galaxies (to g~

Neta A. Bahcall

Rich clusters of galaxies, the largest virialized systems known, provide a powerful tool for the study of cosmology. Some of the fundamental questions that can be addressed with clusters of galaxies include: how did galaxies and large-scale structure form and evolve? What is the amount, composition and distribution of matter in the universe? I review some of

Neta A. Bahcall

I summarize the successes and failures of the most popular current cosmological models in accounting for the available observations. This evaluation, presented as the summary of the 11th Potsdam Workshop on Large-Scale Structure, was discussed by all the participants. I present the ratings given to each model based on a confrontation with the data, and the f

R. De Propris, C. J. Pritchet, W. E. Harris, R. D. McClure

Luminosity Functions have been obtained for very faint dwarf galaxies in the cores of four rich clusters of galaxies (Abell 2052, 2107, 2199 and 2666). It is found that the luminosity function of dwarf galaxies rises very steeply in these clusters, with a power-law slope of α-2.2 (down to absolute limiting magnitudes M_I = -13 and M_B = -11 for H_0 = 75 km/s

Jacek Choloniewski

It is shown that the average magnitude - redshift diagram for a magnitude-limited sample of galaxies can be effectively used for mapping galaxy velocity field. This new approach is quantitatively introduced and applied to the CfA, ESO/LV and ZCAT samples of galaxies. Strong arguments are presented for infall velocities in the Virgo and Fornax superclusters a

J. Christensen-Dalsgaard, T. R. Bedding, G. Houdek, H. Kjeldsen

Following the report of solar-like oscillations in the G0 V star eta Boo (Kjeldsen et al. 1995, AJ 109, 1313), a first attempt to model the observed frequencies was made by Christensen-Dalsgaard et al. (1995, ApJ Letters, in press). This attempt succeeded in reproducing the observed frequency separations, although there remained a difference of about 10 micr

Heath M. Martin, Juan C. Migliore

For an arithmetically Cohen--Macaulay subscheme of projective space, there is a well-known bound for the highest degree of a minimal generator for the defining ideal of the subscheme, in terms of the Hilbert function. We prove a natural extension of this bound for arbitrary locally Cohen--Macaulay subschemes. We then specialize to curves in $\pthree$, and sh

L. Barbieri-Viale, C. Pedrini, C. Weibel

Let $X$ be a complex projective surface with arbitrary singularities. We construct a generalized Abel--Jacobi map $A_0(X)\to J^2(X)$ and show that it is an isomorphism on torsion subgroups. Here $A_0(X)$ is the appropriate Chow group of smooth 0-cycles of degree 0 on $X$, and $J^2(X)$ is the intermediate Jacobian associated with the mixed Hodge structure on

C. Adami, C. T. Brown, M. Haggerty

Using an artificial system of self-replicating strings, we show a correlation between the age of a genotype and its abundance that reflects a punctuated rather than gradual picture of evolution, as suggested long ago by Willis. In support of this correlation, we measure genotype abundance distributions and find universal coefficients. Finally, we propose a s

Frode Torvund, Jan Froyland

The coupled map lattice by Olami {\it et al.} [Phys. Rev. Lett. {\bf 68}, 1244 (1992)] is ``doped'' by letting just {\it one} site have a threshold, $T^{*}_{\rm max}$, bigger than the others. On an $L \times L$ lattice with periodic boundary conditions this leads to a transition from avalanche sizes of about one to exactly $L^2$, and after each avala

Nir J. Shaviv, Arnon Dar

We study a cosmological scenario for gamma ray bursts (GRBs) where relativistic flows interact with dense radiation fields. It is shown that this scenario is plausible in very dense stellar regions which are known to exist in collapsed cores of globular clusters or dense nuclei of galaxies. It yields a correct quantitative description of the temporal behavio

Takayuki Hori

We present a model in which a gauge symmetry of a field theory is intrinsic in the geometry of an extended space time itself. A consequence is that the dimension of our space time is restricted through the BRS cohomology. If the Hilbert space is a dense subspace of the space of all square integrable $C^{\infty}$ functions, the BRS cohomology classes are nont

Francois Englert, Laurent Houart, Paul Windey

The coupling of a Nambu-Goto string to gravity allows for Schwarzschild black holes whose entropy to area relation is $S=(A/4)(1-4μ)$, where $μ$ is the string tension.

Seungjoon Hyun, Jaemo Park, Jae-Suk Park

We study the twisted $N=2$ supersymmetric Yang-Mills theory coupled with the hypermultiplets (TQCD). We suggest that the family of TQCD can be served as a powerful tool for studying the quantum field theoretic properties of the underlying physical theories.

Amon Ilakovac, Bernd A. Kniehl, Apostolos Pilaftsis

Motivated by the recent investigation of neutrinoless $τ$-lepton decays by the CLEO collaboration, we perform a systematic analysis of such decays in a possible new-physics scenario with heavy Dirac/Majorana neutrinos, including heavy-neutrino nondecoupling effects, finite quark masses, and quark as well as meson mixings. We find that $τ$-lepton decays into

H. C. Kao, K. Lee

We investigate quantum nucleation of vortex string loops in the relativistic quantum field theory of a complex scalar field by using the Euclidean path integral. Our initial metastable homogeneous field dominated by the $O(3)$ symmetric bounce solution. The nucleation rate and the critical vortex loop size are obtained approximately. Gradually the initial cu

L. S. F. Olavo

In this continuation paper, we apply the general relativistic quantum theory for one particle systems, derived in paper II of this series, to a simple problem: the quantum Schwartzchild problem, where one particle of mass {\it m% } gravitates around a massive body. The results thus obtained reveal that, in the realm of such a theory, the negative mass conjec

L. S. F. Olavo

The following two papers form a natural development of a previous series of three articles on the foundations of quantum mechanics; they are intended to take the theory there developed to its utmost logical and epistemological consequences. We show in the first paper that relativistic quantum mechanics might accommodate without ambiguities the notion of nega

L. S. F. Olavo

The two previous papers developed quantum mechanical formalism from classical mechanics and two additional postulates. In the first paper it was also shown that the uncertainty relations possess no ontological validity and only reflect the formalism's limitations. In this paper, a Realist Interpretation of quantum mechanics based on these results is elab

L. S. F. Olavo

In this article, the axioms presented in the first one are reformulated according to the special theory of relativity. Using these axioms, quantum mechanic's relativistic equations are obtained in the presence of electromagnetic fields for both the density function and the probability amplitude. It is shown that, within the present theory's scope, Di

L. S. F. Olavo

The objective of this series of three papers is to axiomatically derive quantum mechanics from classical mechanics and two other basic axioms. In this first paper, Schreodinger's equation for the density matrix is fist obtained and from it Schroedinger's equation for the wave functions is derived. The momentum and position operators acting upon the d

H. J. Schulz

Contents I. Introduction II. Fermi Liquids III. Renormalization group for interacting fermions IV. Luttinger liquids V. Transport in a Luttinger liquid VI. The Bethe ansatz: a pedestrian introduction VII. Conclusion and outlook

W. -S. Chung, A. Shafiekhani

The free field realization of irreducible representations of $\os$ is constructed, by a unified and systematic scheme. The $q$-analog of this unified scheme is used to construct $q$-free field realization of irreducible representations of $\uos$. By using these realization, the two point function of $N=1$ superconformal (q-superconformal) model based on $\os

E. G. Floratos, G. K. Leontaris

In various unified extensions of the Minimal Supersymmetric Standard Model, the Yukawa couplings of the third generation are predicted to be of the same order. As a result, low energy measured mass ratios, require large ratios of the standard model Higgs vacuum expectation values, corresponding to a large value of the parameter $tanβ$. We present analytic so

F. H. L. Essler, H. Frahm, A. R. Its, V. E. K. Korepin

We consider the Ferromagnetic-String-Formation-Probability correlation function (FSFP) for the spin-$1\over 2$ Heisenberg XXZ chain. We construct a completely integrable system of integro-difference equations (IDE), which has the FSFP as a $τ$-function. We derive the associated Riemann-Hilbert problem and obtain the large distance asymptotics of the FSFP cor

José Luis Cortés, Elena Rivas, Luis Velázquez

The technique of extended dualization developed in this paper is used to bosonize quantized fermion systems in arbitrary dimension $D$ in the low energy regime. In its original (minimal) form, dualization is restricted to models wherein it is possible to define a dynamical quantized conserved charge. We generalize the usual dualization prescription to includ

Olivier Debarre

Let $G$ be the Grassmannian $G(d,n)$, let $X$ and $Y$ be complete irreducible varieties, and let $X\rightarrow G$ and $Y\rightarrow G$ be morphisms. Hansen proved that $X \times_G Y$ is connected when $codim f(X) + codim g(Y) < n$. We show that the conclusion holds under the often weaker hypothesis $f(X).g(Y).T\ne 0$, where $T$ is the class of $G(d,n-1)$ in

Salvatore De Martino, Silvio De Siena, Fabrizio Illuminati

We extend the definition of generalized coherent states to include the case of time-dependent dispersion. We introduce a suitable operator providing displacement and dynamical rescaling from an arbitrary ground state. As a consequence, squeezing is naturally embedded in this framework, and its dynamics is ruled by the evolution equation for the dispersion. O

Lajos Diosi

The mathematical possibility of coupling two quantum dynamic systems having two different Planck constants, respectively, is investigated. It turns out that such canonical dynamics are always irreversible. Semiclassical dynamics is obtained by letting one of the two Planck constants go to zero. This semiclassical dynamics will preserve positivity, as expecte

G. N. Parfionov, Yu. A. Romashev, R. R. Zapatrine

Following the guidelines of classical differential geometry the `building material&#39; for the tensor calculus in non-commutative geometry is suggested. The algebraic account of moduli of vectors and covectors is carried out.

C. R. Chinn, Ch. Elster, R. M. Thaler, S. P. Weppner

The theory of the elastic scattering of a nucleon from a nucleus is presented in the form of a Spectator Expansion of the optical potential. Particular attention is paid to the treatment of the free projectile$\,-\,$nucleus propagator when the coupling of the struck target nucleon to the residual target must be taken into consideration. First order calculati

Volker Koch

The E814-collaboration has found a component of very low $m_t$ $K^+$ mesons with a slope parameter of $T \sim 15 \, \rm MeV$. We will present a scenario which explains the observed slope parameter and which allows us to predict the expected slope parameter for kaons produced in heavier systems such as Au+Au. We also will discuss the effect of the coulomb int

A. Polls, H. Müther, W. H. Dickhoff

The effects of short-range correlations derived from a realistic meson-exchange potential on the single-particle density matrix in finite nuclei are investigated by analyzing the one-body density in terms of the natural orbits. Basic features of these natural orbits and their spectral distributions are discussed. For many observables it seems to be sufficien

Djordje Minic

We consider some curious aspects of single-species free Fock spaces, such as novel bosonization and fermionization formulae and relations to various physical properties of bosonic particles. We comment on generalizations of these properties to physically more interesting many-species free Fock spaces.

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

A simple connection between the universal $R$ matrix of $U_q(sl(2))$ (for spins $\demi$ and $J$) and the required form of the co-product action of the Hilbert space generators of the quantum group symmetry is put forward. This gives an explicit operator realization of the co-product action on the covariant operators. It allows us to derive the quantum group

P. M. Lavrov, P. Yu. Moshin, A. A. Reshetnyak

Irreducible gauge theories in both the Lagrangian and Hamiltonian versions of the Sp(2)-covariant quantization method are studied. Solutions to generating equations are obtained in the form of expansions in power series of ghost and auxiliary variables up to the 3d order inclusively.

P. M. Lavrov, A. A. Reshetnyak

The one-loop effective action for Einstein gravity in a special one-parameter background gauge is calculated up to first order in a gauge parameter. It is shown that the effective action does not depend upon the gauge parameter on shell.

S. Deser, M. Henneaux

We clarify the physical origin of the difference between gauge properties of conserved currents in abelian and nonabelian theories. In the latter, but not in the former, such currents can always be written on shell as gauge invariants modulo identically conserved, superpotential, terms. For the ``isotopic&#34; vector and the stress tensor currents of spins 1

S. Emery, O. Moritsch, M. Schweda, T. Sommer

We discuss the Chern-Simons theory in three-dimensional curved space-time in the vielbein formalism. Due to the additional presence of the local Lorentz symmetry, beside the diffeomorphisms, we will include a local gravitational supersymmetry (superdiffeomorphisms and super-Lorentz transformations), which allows us to show the perturbative finiteness at all

Ryuichi Nakayama, Toshiya Suzuki

We investigate the integrability of the Schwinger-Dyson equations in $c = 1 - \frac{6}{m(m+1)}$ string field theory which were proposed by Ikehara et al as the continuum limit of the Schwinger-Dyson equations of the matrix chain model. We show the continuum Schwinger-Dyson equations generate a closed algebra. This algebra contains Virasoro algebra but does n

C. C. Lassig, G. C. Joshi

The nonassociativity of the octonion algebra necessitates a bimodule representation, in which each element is represented by a left and a right multiplier. This representation can then be used to generate gauge transformations for the purpose of constructing a field theory symmetric under a gauged octonion algebra, the nonassociativity of which appears as a

Michael S. Chanowitz

Experiments at the LHC are sensitive to the presence or absence of matter quanta at mass scales far beyond the scales they can probe directly. The production of $Z$ boson pairs by gluon-gluon fusion is greatly enhanced if there are ultraheavy quanta that carry $SU(3)_{\rm Color}$ and get their mass from electroweak symmetry breaking. For example, a fourth ge

M. Goodband, M. Hindmarsh

We examine the spectrum of small perturbations around global and local (gauge) abelian vortices, using simple numerical matrix techniques. The results are of interest for both cosmic strings and for their condensed matter analogues, superfluid and superconducting vortices. We tabulate the instabilities of higher winding number vortices, and find several boun

A. H. Chamseddine, Herbi Dreiner

The supersymmetric extension of the standard model suffers from a problem of baryon-number violation. Discrete (and global) symmetries introduced to protect the proton are unstable under gravitational effects. We add a gauged $U(1)_X$ to the standard model gauge group $G_{SM}$ and require it to be anomaly-free. As new (chiral) superfields we only allow $G_{S

P. Agrawal, D. Bowser-Chao, J. Pumplin

We present an optimized and physically motivated method for separating top quark signal events from background events at the Tevatron. For the top quark signal $t\bar t \to e/μ+ 4$ jets, we show how to reject all but $25\%$ of the background in a data sample while retaining $80\%$ of the signal, without introducing bias into the subsequent mass measurement.

M. Heusler

We consider rotating black hole configurations of self-gravitating maps from spacetime into arbitrary Riemannian manifolds. We first establish the integrability conditions for the Killing fields generating the stationary and the axisymmetric isometry (circularity theorem). Restricting ourselves to mappings with harmonic action, we subsequently prove that the

Ulrich Bunke, Martin Olbrich

We provide a simple way to obtain the meromorphic extension of Eisenstein series and Scattering matrices under conditions which generalize the case of discrete groups acting convex cocompactly on hyperbolic spaces.

Alexander G. Reznikov

Main Theorem (3.3): Let $M$ be a compact four-dimensional manifold either with curvature, positive on complex isotropic two-planes, or self-dual of positive scalar curvature. If $π_1 (M)$ admits a nontrivial unitary representation, and $M$ is orientable, then there exists a surjective homomorphism from $π_1 (M)$ on $\bbz$. Corollary: If $π_1 (M)$ is finite,

Sergey A. Merkulov

A general theorem on the existence of natural torsion-free affine connections on a complete family of compact complex submanifolds in a complex manifold is proved. Applications to twistor theory are discussed.

Vladimir Pestov

We show that every complete metric space is homeomorphic to the precise locus of zeros of an entire analytic map from a Hilbert space to a Banach space. As a corollary, every complete separable metric space is homeomorphic to the precise locus of zeros of an entire analytic map between two separable complex Hilbert spaces. AmS TeX 2.1.

F. Dominguez-Adame, E. Macia, B. Mendez, C. L. Roy

We report theoretical electronic structure of Fibonacci superlattices of narrow-gap III-V semiconductors. Electron dynamics is accurately described within the envelope-function approximation in a two-band model. Quasiperiodicity is introduced by considering two different III-V semiconductor layers and arranging them according to the Fibonacci series along th

Leo Radzihovsky

I study the $H_{c2}$ transition within the Ginzburg-Landau model, with $m$-component order parameter $ψ_i$. I find a renormalized fixed point free energy, exact in $m\rightarrow\infty$ limit, suggestive of a $2$nd-order transition in contrast to a general belief of a $1$st-order transition. The thermal fluctuations for $H\neq 0$ force one to consider an infi

R. Podgornik

Arguments are presented to the effect that embedding semi-flexible (wormlike) ideal polymers into a fluctuating, flexible surface leads to an effective attractive orientational interaction between polymer segments that precipitates an orientational ordering transition of the polymer chains on the surface even in the case of otherwise ideal (non-interacting)

Nigel B. Wilding

Monte Carlo simulations within the grand canonical ensemble are used to explore the liquid-vapour coexistence curve and critical point properties of the Lennard-Jones fluid. Attention is focused on the joint distribution of density and energy fluctuations at coexistence. In the vicinity of the critical point, this distribution is analysed using mixed-field f

J. P. Bouchaud, M. Mezard, G. Parisi

We use the mapping between Burgers&#39; equation and the problem of a directed polymer in a random medium in order to study the fully developped turbulence in the $N$ dimensional forced Burgers&#39; equation. The stirring force corresponds to a quenched (spatio temporal) random potential for the polymer. The properties of the inertial regime are deduced from

N. Elstner, A. Sokol, R. R. P. Singh, M. Greven

We present a series expansion study of spin-S square-lattice Heisenberg antiferromagnets. The numerical data are in excellent agreement with recent neutron scattering measurements. Our key result is that the correlation length for S>1/2 strongly deviates from the exact T->0 (renormalized classical, or RC) scaling prediction for all experimentally and numeric

S. W. Allen, A. C. Fabian, A. C. Edge, H. Bohringer

We present the analysis of pointed ROSAT PSPC observations of five of the most luminous, intermediate redshift ($0.1 < z < 0.15$) clusters of galaxies detected in the ROSAT All-Sky Survey. The PSPC data are combined with optical CCD images and spectra to examine the relationship between clusters and their central cluster galaxies (CCGs). Abell 1068, Abell 13

D. Syer, S. Tremaine

We describe a technique for solving the combined collisionless Boltzmann and Poisson equations in a discretised, or lattice, phase space. The time and the positions and velocities of `particles&#39; take on integer values, and the forces are rounded to the nearest integer. The equations of motion are symplectic. In the limit of high resolution, the lattice e

J. C. N. de Araujo, J. A. de Freitas Pacheco, M. Cattani, J. E. Horvath

We have developed a numerical code to study the deformation ($\varepsilon = (I_{zz}-I_{xx})/I_{zz}$, where $I_{ii}$ are the moments of inertia) of neutron stars in rapidly rotation in a fully general relativistic calculation. We have found that the deformation is larger, depending on the angular velocity, than is generally assumed for gravitational wave esti

G. M. Bernstein, R. C. Nichol, J. A. Tyson, M. P. Ulmer

We determine the luminosity function (LF) of galaxies in the core of the Coma cluster for M_R<=-11.4 (assuming H_0=75 km/s/Mpc), a magnitude regime previously explored only in the Local Group. Objects are counted in a deep CCD image of Coma having RMS noise of 27.7 R mag~arcsec$^{-2}$. A correction for objects in the foreground or background of the Coma clus

Karl Glazebrook, Richard Ellis, Basilio Santiago, Richard Griffiths

The excess numbers of blue galaxies at faint magnitudes are a long-standing cosmological puzzle. We present new number-magnitude counts as a function of galactic morphology from the first deep fields of the Cycle 4 Hubble Space Telescope {\it Medium Deep Survey} project. From a sample of 301 galaxies we define counts for elliptical, spiral and irregular/pecu

Nitin Nitsure, Claude Sabbah

We construct a moduli scheme for semistable pre-$\D$-modules with prescribed singularities and numerical data on a smooth projective variety. These pre-$\D$-modules are to be viewed as regular holonomic $\D$-modules with `level structure&#39;. We also construct a moduli scheme for perverse sheaves on the variety with prescribed singularities and other numeri

Nick Evans, Stephen D. H. Hsu, Myckola Schwetz

We show how recent exact results in supersymmetric theories can be extended to models which include {\it explicit} soft supersymmetry breaking terms. We thus derive new exact results for non-supersymmetric models.

Miklos Gyulassy

Highlights of Quark Matter 95 are discussed.

Sumit R. Das, Spenta R. Wadia

We study the quark confinement problem in 2+1 dimensional pure Yang-Mills theory using euclidean instanton methods. The instantons are regularized and dressed Wu-Yang monopoles. The dressing of a monopole is due to the mean field of the rest of the monopoles. We argue that such configurations are stable to small perturbations unlike the case of singular, und

Nichol Brummer, Imperial College, London

Experimental data on the shape of hadronic momentum spectra are compared to theoretical predictions in the context of calculations in the Modified Leading Log Approximation (MLLA), under the assumption of Local Parton Hadron Duality (LPHD). Considered are experimental measurements at $e^+e^-$-colliders of $ξ_p^*$, the position of the maximum in the distribut

H. T. Cho, R. Kantowski

We evaluate zeta-functions $ζ(s)$ at $s=0$ for invariant non-minimal 2nd-order vector and tensor operators defined on maximally symmetric even dimensional spaces. We decompose the operators into their irreducible parts and obtain their corresponding eigenvalues. Using these eigenvalues, we are able to explicitly calculate $ζ(0)$ for the cases of Euclidean sp

H. T. Cho, R. Kantowski

We show that the trace anomaly for gravitons calculated using the usual effective action formalism depends on the choice of gauge when the background spacetime is not a solution of the classical equation of motion, that is, when off-shell. We then use the gauge independent Vilkovisky-DeWitt effective action to restore gauge independence to the off-shell case

Chris Kolda, Stephen P. Martin

We investigate how the predictions of the Minimal Supersymmetric Standard Model are modified by D-term contributions to soft scalar masses, which arise whenever the rank of the gauge group at very high energies is greater than four. We give a parameterization of the most general such contributions that can occur when the unbroken gauge symmetry is an arbitra

B. Alles, M. Beccaria

The O(n) non-linear $σ$-model is simulated on 2-dimensional regular and random lattices. We use two different levels of randomness in the construction of the random lattices and give a detailed explanation of the geometry of such lattices. In the simulations, we calculate the mass gap for $n=3, 4$ and 8, analysing the asymptotic scaling of the data and compu

B. Kaulakys

We investigate the effect of repeated measurement for quantum dynamics of the suppressed systems which classical counterparts exhibit chaos. The essential feature of such systems is the quantum localization phenomena strongly limiting motion in the energy space. Repeated frequent measurement of suppressed systems results to the delocalization. Time evolution

P. Kratzer, B. Hammer, J. K. Norskov

The energetics of H$_2$ interacting with the Si(100) surface is studied by means of {\em ab initio} total energy calculations within the framework of density functional theory. We find a direct desorption pathway from the mono-hydride phase which is compatible with experimental activation energies and demonstrate the importance of substrate relaxation for th

M. Honda, T. Kajita, S. Midorikawa, K. Kasahara

Atmospheric neutrino-fluxes are calculated over the wide energy range from 30 MeV to 3,000 GeV for the study of neutrino-physics using the data from underground neutrino-detectors. The atmospheric muon-flux at high altitude and at sea level is studied to calibrate the neutrino-fluxes at low energies and high energies respectively. The agreement of our calcul