July 1996 arXiv papers — page 6

Anton Yu. Alekseev, Vadim V. Cheianov, Jürg Fröhlich

We propose a new calculation of the DC conductance of a 1-dimensional electron system described by the Luttinger model. Our approach is based on the ideas of Landauer and Büttiker and on the methods of current algebra. We analyse in detail the way in which the system can be coupled to external reservoirs. This determines whether the conductance is renormaliz

S. F. Burlatsky, A. M. Cazabat, M. Moreau, G. Oshanin

In this paper we study kinetics of spreading of thin liquid films on solid interfaces. We present an overview of current experimental picture and discuss available theoretical approaches and their limitations. We report some new experimental results on spreading of molecularly thin liquid films and propose an analytically solvable microscopic model, which re

S. Sridhar, S. Oxx, B. A. Willemsen, H. Srikanth

Recently, Mun et.al. (Phys. Rev. Lett., 76, 2790 (1996)) have published their results on single crystal YNi_2B_2C, claiming that their experimental observations can be explained in terms of formation of Vortex Glass and Lattice melting. Our experiments, carried out on samples obtained from the SAME source, reveal a much richer phase diagram and span wider re

Vladimir Buzek, Mark Hillery

We analyze to what extent it is possible to copy arbitrary states of a two-level quantum system. We show that there exists a "universal quantum copying machine", which approximately copies quantum mechanical states in such a way that the quality of its output does not depend on the input. We also examine a machine which combines a unitary transformat

Taco Nieuwenhuis, J. A. Tjon

The Bethe-Salpeter amplitude is expanded on a hyperspherical basis, thereby reducing the original 4-dimensional integral equation into an infinite set of coupled 1-dimensional ones. It is shown that this representation offers a highly accurate method to determine numerically the bound state solutions. For generic cases only a few hyperspherical waves are nee

G. Boyd, F. Karsch, E. Laermann, M. Oevers

Results on the phase transition in QCD with two flavours of light staggered fermions from an ongoing simulation are presented. We find the restoration of the chiral SU(2) x SU(2) symmetry, but not of the axial U_A(1) symmetry.

M. N. Chernodub, F. V. Gubarev, M. I. Polikarpov

We discuss the Aharonov--Bohm effect in three and four dimensional non--compact lattice Abelian Higgs model. We show analytically that this effect leads to the long--range Coulomb interaction of the charged particles, which is confining in three dimensions. The Aharonov--Bohm effect is found in numerical calculations in 3D Abelian Higgs model.

François Goy

In the last two decades, theories explaining the same experiments as well as special relativity does, were developed by using different synchronization procedures. All of them are ether-like theories. Most authors believe these theories to be equivalent to special relativity, but no general proof was ever brought. By means of a Gedankenexperiment on light ab

François Goy

The special relativistic test theory of Mansouri and Sexl is sketched. Theories based on different clock synchronisations are found to be equivalent to special relativity, as regards experimental results. The conventionality of clock synchronisation is shown not to hold, by means of an example, in a simple accelerated system and through the principle of equi

Victor Yakhot

A dynamic equation for velocity structure functions $S_{n}(r) = <(u(x)-u(x&#39;))^{n}>$ in strong turbulence is derived in the one-loop (eddy viscosity) approximation. This homogemeous differential equation yields scaling exponents $ξ_{n}$ in the relations $S_{n}(r)\propto r^{ξ_{n}}$ which are in a very good agreement with experimental data.

Victor S. L&#39;vov, Evgenii Podivilov, Itamar Procaccia

On the basis of the Navier-Stokes equations we develop the statistical theory of many space-time correlation functions of velocity differences. Their time dependence is {\em not} scale invariant: $n$-order correlations functions exhibit $n-1$ distinct decorrelation times that are characterized by $n-1$ anomalous dynamical scaling exponents. We derive exact s

David Clarke, Steven Strong

On the basis of a calculation of the exact interliquid hopping rate and an approximate single particle Green&#39;s function, we present new evidence for the existence of a phase of relevant but incoherent inter-Luttinger liquid transport. This phase of ``confined coherence&#39;&#39; occurs when the Luttinger liquid exponent alpha satisfies alpha_c<alpha<1/2.

Karsten Flensberg

We study cotunneling in a double junction Coulomb blockade device under the influence of time dependent potentials. It is shown that the ac-bias leads to photon assisted cotunneling which in some cases may dominate the transport. We derive a general non-perturbative expression for the tunneling current in the presence of oscillating potentials and give a per

P. Bressler, M. Saito, B. Youssin

We introduce the notion of filtered perversity of a filtered differential complex on a complex analytic manifold $X$, without any assumptions of coherence, with the purpose of studying the connection between the pure Hodge modules and the \lt-complexes. We show that if a filtered differential complex $(\cM^\bullet,F_\bullet)$ is filtered perverse then $\aDR(

L. V. Dung, T. N. Truong

It is explicitly shown that either the approximate solution of the integral equation for the inverse of the pion form factor, or the result of the Padé approximant method of resumming the one loop Chiral Perturbation Theory (CPTH) are equivalent to the standard vector meson dominance (VMD) models, using the vector meson coupling to two pseudoscalars given by

I. B. Khriplovich, A. I. Milstein, R. A. Sen'kov

The contact Darwin term is demonstrated to be of the same origin as the spin-orbit interaction. The $(Z\alpha)^4 m^3/M^2$ correction to the Lamb shift, generated by the Darwin term, is found for an arbitrary nonvanishing spin of the nucleus, both half-integer and integer. There is also a contribution of the same nature to the nuclear quadrupole moment.

T. Padmanabhan

The gravitational clustering of collisionless particles in an expanding universe is modelled using some simple physical ideas. I show that it is possible to understand the nonlinear clustering in terms of three well defined regimes: (1) linear regime; (2) quasilinear regime which is dominated by scale-invariant radial infall and (3) nonlinear regime dominate

M. Baig, J. Clua, A. Jaramillo

We study an ensemble of closed random paths, embedded in R^3, with a curvature dependent action. Previous analytical results indicate that there is no crumpling transition for any finite value of the curvature coupling. Nevertheless, in a high statistics numerical simulation, we observe two different regimes for the specific heat separated by a rather smooth

H. Lu, C. N. Pope, P. K. Townsend

We examine $(D-2)$-brane solutions in supergravities, showing that they fall into four categories depending on the details of the dilaton coupling. In general they describe domain walls, although in one of the four categories the metric describes anti-de Sitter spacetime. We study this case, and its $S^1$ dimensional reduction to a more conventional domain w

Yuri B. Suris

Unexpected relations are found between the Toda lattice, the relativistic Toda lattice and the Bruschi--Ragnisco lattice, as well as between their integrable discretizations.

Yuri Orlov

The most peculiar, specifically quantum, features of quantum mechanics --- quantum nonlocality, indeterminism, interference of probabilities, quantization, wave function collapse during measurement --- are explained on a logical-geometrical basis. It is shown that truths of logical statements about numerical values of quantum observables are quantum observab

Astrid Lambrecht, Marc-Thierry Jaekel, Serge Reynaud

We contest the recent claim by C. Eberlein (Physical Review Letters 76 (1996) 3842) that sonoluminescence may be explained in terms of quantum vacuum radiation. Due to fundamental physical limitations on bubble surface velocity, the predicted number of photons per flash is indeed much smaller than unity. Therefore, quantum vacuum radiation cannot be consider

Anatol N. Kirillov, Atsuo Kuniba, Tomoki Nakanishi

The spectral decomposition of the path space of the vertex model associated to the vector representation of the quantized affine algebra $U_q(\hat{sl}_n)$ is studied. We give a one-to-one correspondence between the spin configurations and the semi-standard tableaux of skew Young diagrams. As a result we obtain a formula of the characters for the degeneracy o

G. Bartnitzky, H. Clement, P. Czerski, H. Müther

An effective nucleon-nucleon interaction calculated in nuclear matter from the Bonn potential has been parametrized in terms of a local density- and energy-dependent two-body interaction. This allows to calculate the real part of the nucleus-nucleus scattering potential and to test this effective interaction over a wide region of densities ($ρ\leq 3ρ_0$) pro

G. A. Lalazissis, J. König, P. Ring

A new parameterization for an effective non-linear Lagrangian density of relativistic mean field (RMF) theory is proposed, which is able to provide an excellent description not only for the properties of stable nuclei but also for those far from the valley of beta-stability. In addition recently measured superdeformed mimima in the Hg-region are reproduced w

M. Bruno, P. F. Mastinu, M. Belkacem, M. D&#39;Agostino

The signals theoretically predicted for the occurrence of a critical behavior (conditional moments of charge distributions, Campi scatter plot, fluctuations of the size of the largest fragment, power law in the charge distribution, intermittency) have been found for peripheral events in the reaction Au+Au at 35 MeV/u. The same signals have been studied with

C. D. Keith, C. R. Gould, D. G. Haase, M. L. Seely

Measurements of polarized neutron--polarized $^3$He scattering are reported. The target consisted of cryogenically-polarized solid $^3$He, thickness 0.04 atom/b and polarization 40%. The longitudinal and transverse total cross-section differences $Δσ_L$ and $Δσ_T$ were measured for incident neutron energies 2-8 MeV. The results are compared to phase-shift pr

Eckhard Pehlke, Nikolaj Moll, Matthias Scheffler

The equilibrium shape of strained InAs quantum dots grown epitaxially on a GaAs(001) substrate is derived as a function of volume. InAs surface energies are calculated within density-functional theory, and a continuum approach is applied for the elastic relaxation energies.

Axel Gross, Michel Bockstedte, Matthias Scheffler

Ab initio molecular dynamics calculations of deuterium desorbing from Si(100) have been performed in order to monitor the energy redistribution among the hydrogen and silicon degrees of freedom during the desorption process. The calculations show that part of the potential energy at the transition state to desorption is transferred to the silicon lattice. Th

Axel Gross, Matthias Scheffler

Six-dimensional quantum dynamical calculations of the scattering of H_2 from a Pd(100) surface using a potential energy surface derived from density-functional theory calculations are presented. Due to the corrugation and anisotropy of the PES strong off-specular and rotationally inelastic diffraction is found. The dependence of the diffraction intensitities

J. Dai, J. F. Gunion, R. Vega

We update our earlier results regarding detection of $gg\to b\anti b h\to 4b$ ($h=h^0,H^0,A^0$) to incorporate the very high $b$-tagging efficiencies and purities that are now anticipated at the LHC. New results for the Tev$^*$ are given, and indicate substantial potential for these modes. The complementarity of the $H^0\to h^0h^0 \to 4b$ final state mode is

A Donnachie, P V Landshoff

Existing data for large-$t$ $pp$ elastic-scattering differential cross-sections are energy-independent and behave as $t^{-8}$. This has been explained in terms of triple-gluon exchange, or alternatively through triple-singlet exchange. A discussion is given of the problems raised by each of these explanations, and of the possibility that at RHIC or LHC energ

M. M. Boyce, M. A. Doncheski, H. König

The possibility of studying superstring inspired \mbox{${\rm E}_6$} phenomenology at high energy hadron colliders is investigated. A very simple low energy rank-5 Supersymmetric (N=1) model is considered, which consists of three scalar-Higgses, $H^0_{i=1,2,3}\,$, two charged-Higgses, $H^\pm\,$, one pseudo-scalar-Higgses, $P^0\,$, and an extra vector boson, t

C. D. Froggatt, H. B. Nielsen

We argue that some of the parameters in the laws of Nature would be well understood, under the assumption that there is an influence from the future as well as from the past, in the sense that the principle of locality is not valid at the fundamental level. However, locality is supposed to be broken only in the mild way that all the non-local influence comes

I. B. Khriplovich, A. I. Milstein

We rederive here in a simple and transparent way the master formula for the dominant part of large relativistic corrections to the positronium decay rate.

D. S. Henty, C. Parrinello, D. G. Richards, J. I. Skullerud

We discuss strategies for using lattice QCD to investigate some topics in strong interaction phenomenology which are usually related to soft pomeron exchange. These include hadronic cross-sections at high energies and diffractive scattering at HERA. Some numerical results are presented in the framework of the Landshoff-Nachtmann pomeron model.

S. M. Bilenky, C. Giunti, W. Grimus

All the possible schemes of neutrino mixing with four massive neutrinos inspired by the existing experimental indications in favor of neutrino mixing are considered in a model independent way. Assuming that in short-baseline experiments only one mass-squared difference is relevant, it is shown that the scheme with a neutrino mass hierarchy is not compatible

S. Esposito

We study, in the framework of the Standard Model, the propagation of (pure) Majorana neutrinos in a typical stellar medium and show that Majorana neutrino matter oscillations are completely indistinguishable from Dirac ones, even if in the case of no family mixing Majorana neutrinos can be distinguished from Dirac ones in the non-relativistic limit. Moreover

L. L. Salcedo

Let a ``complex probability&#39;&#39; be a normalizable complex distribution $P(x)$ defined on $\R^D$. A real and positive probability distribution $p(z)$, defined on the complex plane $\C^D$, is said to be a positive representation of $P(x)$ if $\langle Q(x)\rangle_P = \langle Q(z)\rangle_p$, where $Q(x)$ is any polynomial in $\R^D$ and $Q(z)$ its analytica

K. M. Bitar, R. G. Edwards, U. M. Heller, A. D. Kennedy

We study QCD with two flavors of dynamical Wilson fermions at $β= 5.5$ and three values of $κ$. The corresponding pion masses are 0.375, 0.324 and 0.262 in lattice units, with pion to rho mass ratios of 0.76, 0.71 and 0.62, respectively. We use the configurations to compute the heavy quark potential, leading to lattice spacings of 0.110, 0.105 and 0.099 fm,

M. A. Halasz, T. Kalkreuter, J. J. M. Verbaarschot

Recently, Kalkreuter obtained complete Dirac spectra for $SU(2)$ lattice gauge theory both for staggered fermions and for Wilson fermions. The lattice size was as large as $12^4$. We performed a statistical analysis of these data and found that the eigenvalue correlations can be described by the Gaussian Symplectic Ensemble for staggered fermions and by the

J. Engels, T. Scheideler

We investigate the pseudo specific heat of SU(2) gauge theory near the crossover point on $4^4$ to $16^4$ lattices. Several different methods are used to determine the specific heat. The curious finite size dependence of the peak maximum is explained from the interplay of the crossover phenomenon with the deconfinement transition occurring due to the finite

M. Baig, J. Clua

We present some results coming from a Monte Carlo simulation of a set of random paths with a curvature dependent action. This model can be considered as a toy model of the theory of random surfaces. The transition from free to rigid random paths has been analyzed and the similitude with the crumpling transition have been pointed out.

C. B. Lang, P. Petreczky

We have studied the U(1) gauge field theory with Villain (periodic Gaussian) action on spherelike lattices. The effective size of the systems studied ranges from 6 to 16. We do not observe any 2-state signal in the distribution function of the plaquette expectation value at the deconfining phase transition. The observed finite-size scaling behavior is consis

Matthias Lesch

This text is a revised version of the authors Habilitationsschrift which was submitted to the University of Augsburg, 1993. Fuchs type differential operators are used to model the analysis on manifolds with cone--like singularities, or more general, stratified spaces. This book provides a self--contained treatment of the analysis of the heat equation and ind

Deniz Ertas, David R. Nelson

We discuss the onset of irreversibility and entanglement of vortex lines in high Tc superconductors due to point disorder and thermal fluctuations using a simplified cage model. A combination of Flory arguments, known results from directed polymers in random media, and a Lindemann criterion are used to estimate the field and temperature dependence of irrever

J. Jaklic, P. Prelovsek

The single-particle spectral functions $A({\bf k},ω)$ and self-energies $Σ({\bf k},ω)$ are calculated within the $t-J$ model using the finite-temperature Lanczos method for small systems. A remarkable asymmetry between the electron and hole part is found. The hole (photoemission) spectra are overdamped, with ${\rm Im} Σ\propto ω$ in a wide energy range, cons

K. Flensberg, L. W. Molenkamp

We describe two experiments to study the influence of fluctuations in the electron charge on the transport properties of a quantum dot. First, we scan a device from single- to double quantum-dot behavior by varying the conductance of a connecting point contact. Second, we measure the dependence of the charging energy on the conductance of the barriers. The e

L. S. Levitov, H. -W. Lee, G. B. Lesovik

A theory of electron counting statistics in quantum transport is presented. It involves an idealized scheme of current measurement using a spin 1/2 coupled to the current so that it precesses at the rate proportional to the current. Within such an approach, counting charge without breaking the circuit is possible. As an application, we derive the counting st

L. S. Levitov, A. V. Shytov

We present an effective action approach for the problem of Coulomb blocking of tunneling. The method is applied to the ``strong coupling&#39;&#39; problem arising near zero bias, where perturbation theory diverges. By a semiclassical argument, we obtain electrodynamics in imaginary time, and express the anomaly through exact conductivity of the system $σ(ω,

Andrew R. Golding, Dan Roth

Multiplicative weight-updating algorithms such as Winnow have been studied extensively in the COLT literature, but only recently have people started to use them in applications. In this paper, we apply a Winnow-based algorithm to a task in natural language: context-sensitive spelling correction. This is the task of fixing spelling errors that happen to resul

Al Kogut

The Diffuse Microwave Emission Survey (DIMES) has been selected for a mission concept study for NASA&#39;s New Mission Concepts for Astrophysics program. DIMES will measure the frequency spectrum of the cosmic microwave background and diffuse Galactic foregrounds at centimeter wavelengths to 0.1% precision (0.1 mK), and will map the angular distribution to 2

Martin D. Weinberg

Evolution and disruption of galaxies orbiting in the gravitational field of a larger cluster galaxy are driven by three coupled mechanisms: 1) the heating due to its time dependent motion in the primary; 2) mass loss due to the tidal strain field; and 3) orbital decay. Previous work demonstrated that tidal heating is effective well inside the impulse approxi

D. A. Varshalovich, A. Y. Potekhin, A. V. Ivanchik, V. E. Panchuk

Contemporary multidimensional cosmological theories predict different variations of fundamental physical constants in course of the cosmological evolution. On the basis of the QSO spectra analysis, we show that the fine-structure constant α=e^2/(\hbar c) and the proton-to-electron mass ratio μ=m_p/m_e reveal no statistically significant variation over the la

Christoph Durr, Peter Hoyer

We give a quantum algorithm to find the index y in a table T of size N such that in time O(c sqrt N), T[y] is minimum with probability at least 1-1/2^c.

P. Grüter, F. Laloë, A. E. Meyerovich, W. Mullin

We study in more detail the properties of the generalized Beth Uhlenbeck formula obtained in a preceding article. This formula leads to a simple integral expression of the grand potential of the system, where the interaction potential appears only through the matrix elements of the second order Ursell operator $U_{2}$. Our results remain valid for significan

Jeremy Kepner, Frank Summers, Michael Strauss

We present a new statistic-the redshift dispersion-- which may prove useful for comparing next generation redshift surveys (e.g., the Sloan Digital Sky Survey) and cosmological simulations. Our statistic is specifically designed for the projection of phase space which is directly measured by redshift surveys. We find that the redshift dispersion of galaxies

Peter Schneider, Matthias Bartelmann

The projected mass of a gravitational lens inside (circular) apertures can be derived from the measured shear inside an annulus which is caused by the tidal field of the deflecting mass distribution. Here we show that also the multipoles of the two-dimensional mass distribution can be derived from the shear in annuli. We derive several expressions for these

H. Walliser, G. Holzwarth

Electro magnetic transition form factors for the excitation of the Delta33-resonance are evaluated in the Skyrme model. They crucially rely on rotationally induced deformations of the hedgehog soliton which are suppressed by two N_C-orders as compared to the leading parts of the isovector current. Partial photon coupling through vector mesons is included in

C. Barrabes, V. P. Frolov

A classical model for the interior structure of a Schwarzshild black hole which consists in creating multiple de Sitter universes with lightlike boundaries is proposed.The interaction of the boundaries is studied and a scenario leading to disconnected de Sitter universes is described.

A. V. Smilga

We derive exact analytical expressions for the critical amplitudes $A_ψ$, $A_{gap}$ in the scaling laws for the fermion condensate $<\bar ψψ> = A_ψm^{1/3} g^{2/3}$ and for the mass of the lightest state $M_{gap} = A_{gap} m^{2/3} g^{1/3}$ in the Schwinger model with two light flavors, $m \ll g$. $A_ψ$ and $A_{gap}$ are expressed via certain universal amplitu

Khaled Abdel-Khalek

Quaternion analysis is considered in full details where a new analyticity condition in complete analogy to complex analysis is found. The extension to octonions is also worked out.

Seiji Terashima, Sung-Kil Yang

Effective superpotentials for the phase with a confined photon are obtained in $N=1$ supersymmetric gauge theories. We use the results to derive the hyperelliptic curves which describe the Coulomb phase of $N=2$ theories with classical gauge groups, and thus extending the prior result for $SU(N_c)$ gauge theory by Elitzur et al. Moreover, adjusting the coupl

Shibaji Roy

We consider the compactification of type IIB superstring theory on K3 $\times$ K3. We obtain the massless spectrum of the resulting two dimensional theory and show that the model is free of gravitational anomaly. We then consider an orbifold and an orientifold projection of the above model and find that their spectrum match identically and are anomaly-free a

Sumit R. Das, Samir D. Mathur

We investigate some aspects of the spectrum of D-branes and their interactions with closed strings. As argued earlier, a collection of many D-strings behaves, at large dilaton values, as a single multiply wound string. We use this result and T-duality transformations to show that a similar phenomenon occurs for effective strings produced by wrapping p-branes

Jun&#39;ichi Shiraishi, Mahito Kohmoto

An effective Chern-Simons theory for the quantum Hall states with edges is studied by treating the edge and bulk properties in a unified fashion. An exact steady-state solution is obtained for a half-plane geometry using the Wiener-Hopf method. For a Hall bar with finite width, it is proved that the charge and current distributions do not have a diverging si

A. Niégawa

The production rate of a soft photon from a hot quark-gluon plasma is computed to leading order at logarithmic accuracy. The canonical hard-thermal-loop resummation scheme leads to logarithmically divergent production rate due to mass singularities. We show that these mass singularities are screened by employing the effective hard-quark propagator, which is

Victor M. Yakovenko, Hsi-Sheng Goan

This paper reviews recent developments in the theory of the quantum Hall effect (QHE) in the magnetic-field-induced spin-density-wave (FISDW) state of the quasi-one-dimensional organic conductors (TMTSF)$_2$X. The origin and the basic features of the FISDW are reviewed. The QHE in the pinned FISDW state is derived in several simple, transparent ways, includi

Adonai S. Sant&#39;Anna, Decio Krause

An axiomatics for indistinguishability of elementary particles in terms of hidden variables is presented in a manner which depart from the standard approaches usually given to hidden variables. Quantum distribution functions are also discussed and some related lines of work are suggested.

Luc Lapointe, Luc Vinet

The Macdonald polynomials can be obtained by acting on the constant 1 with creation operators. Three different expressions for these operators are derived, one from the other, in a rather succint way. When the last of these expressions is used, the formalism is seen to imply straightforwardly the integrality of the (q,t)-Kostka coefficients, that is of the e

Luc Lapointe, Luc Vinet

We present formulas of Rodrigues type giving the Macdonald polynomials for arbitrary partitions through the repeated application of creation operators on the constant 1. Three expressions for the creation operators are derived one from the other. When the last of these expressions is used, the associated Rodrigues formula readily implies the integrality of t

Luc Lapointe, Luc Vinet

Formulas of Rodrigues-type for the Macdonald polynomials are presented. They involve creation operators, certain properties of which are proved and other conjectured. The limiting case of the Jack polynomials is discussed.

L. Frappat, A. Sciarrino, S. Sciuto, P. Sorba

We give a realization of the quantum affine Lie algebras $\uqa$ and $\uqc$ in terms of anyons defined on a one-dimensional chain (or on a two-dimensional lattice), the deformation parameter $q$ being related to the statistical parameter $ν$ of the anyons by $q = e^{iπν}$. In the limit of the deformation parameter going to one we recover the Feingold-Frenkel

J. Ross Thomson, Jaume Casademunt, Francois Drolet, Jorge Vinals

Flow induced by a random acceleration field (g-jitter) is considered in two related situations that are of interest for microgravity fluid experiments: the random motion of an isolated buoyant particle and coarsening of a solid-liquid mixture. We start by analyzing in detail actual accelerometer data gathered during a recent microgravity mission, and obtain

D. H. E. Gross

Microcanonical thermodynamics (MT) is analysed for phase transitions of first and second order in finite systems. The transiton temperature, the latent heat and the surface tension of first order transitions can easily be determined by MT from the caloric equation of state T(E). The outstandig problem of the physical meaning of its backbending is clarified f

Wu Yuanfang, Ulrich Heinz

We study the reconstruction of the source function in space-time directly from the measured HBT correlation function using the Maximum Entropy Principle. We find that the problem is ill-defined without at least one additional theoretical constraint as input. Using the requirement of a finite source lifetime for the latter we find a new Gaussian parametrizati

D. H. E. Gross, A. S. Botvina

This comment on Moretto et al.PRL 76:372,1996 argues that the IMF-charge distribution may not be useful as signal for phase-transitions in nuclear multifragmentation. Fluctuations of different origin may corrupt this signal. Energy conservation is as important as charge conservation. The caloric equation of state is more safe.

H. Eckstein, W. Schattke, M. Reigrotzki, R. Redmer

Variational quantum Monte Carlo calculations are reported for the bulk GaAs semiconductor in order to present values for the ground-state energy, the lattice constant, the bulk modulus, and some derived properties. The statistical accuracy is significantly higher than the remaining differences to the experimental values, especially for the total-energy upper

Gideon Schechtman, Thomas Schlumprecht, Joel Zinn

The Gaussian Correlation Conjecture states that for any two symmetric, convex sets in n-dimensional space and for any centered, Gaussian measure on that space, the measure of the intersection is greater than or equal to the product of the measures. In this paper we obtain several results which substantiate this conjecture. For example, in the standard Gaussi

P. Hitczenko, Stanisław Kwapień, Wenbo V. Li, Gideon Schechtman

We provide necessary and sufficient conditions for hypercontractivity of the minima of nonnegative, i.i.d. random variables and of both the maxima of minima and the minima of maxima for such r.v.&#39;s. It turns out that the idea of hypercontractivity for minima is closely related to small ball probabilities and Gaussian correlation inequalities.

Nathan Seiberg, Edward Witten

We study four dimensional $N=2$ supersymmetric gauge theories on $R^3 \times S^1$ with a circle of radius $R$. They interpolate between four dimensional gauge theories ($R=\infty$) and $N=4$ supersymmetric gauge theories in three dimensions ($R=0$). The vacuum structure can be determined quite precisely as a function of $R$, agreeing with three and four-dime

A. V. Zabrodin

A brief non-technical review of the recent study of classical integrable structures in quantum integrable systems is given. It is explained how to identify the standard objects of quantum integrable systems (transfer matrices, Baxter&#39;s $Q$-operators, etc) with elements of classical non-linear integrable difference equations ($τ$-functions, Baker-Akhiezer

L. Frappat, A. Sciarrino, P. Sorba

The main definitions and properties of Lie superalgebras are proposed a la facon de a short dictionary, the different items following the alphabetical order. The main topics deal with the structure of simple Lie superalgebras and their finite dimensional representations; rather naturally, a few pages are devoted to supersymmetry. This modest booklet has two

M. B. Barbaro, A. Molinari, F. Palumbo

A new approach to bosonization in relativistic field theories and many-body systems, based on the use of fermionic composites as integration variables in the Berezin integral defining the partition function of the system, is tested. The method is applied to the study of a simplified version of the BCS model.

A. Marshakov

I review the appearence of integrable structures in the formulation of exact nonperturbative solutions to $4d$ supersymmetric quantum gauge theories. Various examples of ${\cal N}\geq 2$ SUSY Yang-Mills nonperturbative solutions are adequately described in terms of the (deformations of the) finite-gap solutions to integrable models: through the generating di

Bruno Iochum, Daniel Kastler, Thomas Schucker

We give the details of the computation of the Chamseddine-Connes action by combination of a Lichnerowicz formula with the heat kernel expension.

Paolo Cea, Luigi Tedesco

The perturbation theory with a variational basis is constructed and analyzed.The generalized Gaussian effective potential is introduced and evaluated up to the second order for selfinteracting scalar fields in one and two spatial dimensions. The problem of the renormalization of the mass is discussed in details. Thermal corrections are incorporated. The comp

J. Cruz, J. Navarro-Salas

We study the evaporation process of 2D black holes in thermal equilibrium when the incoming radiation is turned off. Our analysis is based on two different classes of 2D dilaton gravity models which are exactly solvable in the semiclassical aproximation including back-reaction. We consider a one parameter family of models interpolating between the Russo-Suss

H. W. Hamber, R. M Williams

The issue of local gauge invariance in the simplicial lattice formulation of gravity is examined. We exhibit explicitly, both in the weak field expansion about flat space, and subsequently for arbitrarily triangulated background manifolds, the exact local gauge invariance of the gravitational action, which includes in general both cosmological constant and c

Soo-Jong Rey

Implications of string-string dualities to cosmological string vacua are discussed. Cosmological vacua of classical string theories comprise of disjoint classses mapped one another by scale-factor T-duality. Each classes are, however, afflicted with initial/final cosmological singularities. It is argued that quantum string theories and string-string dualitie

L. E. Gordon, J. K. Storrow

We present new improved parton distributions for the photon. We fit {\bf all} available data on the photon structure function, $F^γ_{2}(x,Q^2)$, with $Q^2\ge 3$ GeV$^2$, in order to determine the quark distributions. We also pay particular attention to the gluon distribution in the photon, $g^γ(x,Q^2)$, which has been poorly constrained in earlier analyses w

A. Dobado, J. Morales, J. R. Pelaez, M. T. Urdiales

In this paper we study the large N limit of the Standard Model Higgs sector with $Nλ$, $Ng^2$ and $Ng&#39;^2$ constant and $N$ being the number of would-be Goldstone bosons. Despite the simplicity of this method at leading order, its results satisfy simultaneously important requirements such as unitarity and the low-energy theorems in contrast with other mor

C. Lucchesi

I present a criterion for all-order finiteness in N=1 SYM theories. Three applications are given; they yield all-order finite N=1 SYM models with global symmetries of the superpotential.

Andrey G. Grozin, Matthias Neubert

Using methods developed for hard exclusive QCD processes, we calculate the asymptotic behaviour of heavy-meson form factors at large recoil. It is determined by the leading- and subleading-twist meson wave functions. For $1\ll |v\cdot v&#39;|\ll m_Q/Λ$, the form factors are dominated by the Isgur--Wise function, which is determined by the interference betwee

A. V. Sidorov, M. V. Tokarev

The deep-inelastic deuteron structure function (SF) $F_2^D(x_D,Q^2)$ in the covariant approach in light-cone variables is considered. The $x_D$ and $Q^2$-dependences of SF are calculated. The QCD analysis of generated data both for non-cumulative $x_D<1$ and cumulative $x_D>1$ ranges was performed. It was shown that $Q^2$-evolution of SF is valid for ranges

Chengxing Zhai

We derive a formula for computing the transition rate for a process involving particles with momentum much higher than the temperature and chemical potentials in a plasma by using an effective field theory approach. We apply it to collision of charged particles with hard momentum inside a QED plasma. The Debye screening effect and the damping of a charged pa

Zurab Berezhiani

The concept of non-abelian horizontal symmetry $SU(3)_H$ can greatly help in understanding the fermion and sfermion flavour structures in supersymmetric grand unification. For the sake of demonstration the $SU(5)\times SU(3)_H$ model, suggested earlier in ref. \cite{PLB85}, is revisited. We show that under very simple and natural assumption it links the sfer

Ann E. Nelson, Matthew J. Strassler

We describe a realistic, renormalizable, supersymmetric ``quindecuplet&#39;&#39; model in which the top quark, left handed bottom quark, and up-type Higgs boson are composite, with a compositeness scale $\sim 1-3$ TeV. The top-Higgs Yukawa coupling is a dynamically generated strong interaction effect, and is naturally much larger than any other Yukawa coupli

M. Suzuki

Topologically nontrivial time-dependent solutions of the classical nonlinear sigma model are studied as candidates of the disoriented chiral condensate (DCC) in 3+1 dimensions. Unlike the analytic solutions so far discussed, these solutions cannot be transformed into isospin-uniform ones by chiral rotations. If they are produced as DCC's, they can be detecte

W. Franzki, J. Jersak, C. B. Lang, T. Neuhaus

Some interesting nonperturbative properties of the strongly coupled 4D compact U(1) lattice gauge theories, both without and with matter fields, are pointed out. We demonstrate that the pure gauge theory has a non-Gaussian fixed point with $ν= 0.365(8)$ at the second order confinement-Coulomb phase transition. Thus a non-asymptotic free and nontrivial contin