arXiv papers from February 1997

M. B. Hastings

The two-dimensional one-component logarithmic Coulomb gas is mapped onto a non-hermitian fermionic field theory. At $\beta=2$, the field theory is free. Correlation functions are calculated and a perturbation theory is discussed for extending to other $\beta$. A phase transition is found at the mean-field level at large $\beta$. Some results are extended to

Matt Visser

Building on a series of earlier papers [gr-qc/9604007, gr-qc/9604008, gr-qc/9604009], I investigate the various point-wise and averaged energy conditions in the Unruh vacuum. I consider the quantum stress-energy tensor corresponding to a conformally coupled massless scalar field, work in the test-field limit, restrict attention to the Schwarzschild geometry,

M. Maris S. T. Petcov

Day - Night asymmetries and electronic spectra distortions for the Super - Kamiokande detector are computed for the transition nu_e -> nu_mu(tau) and for a set of neutrino parameters. The results show the possibility to enhance up to a factor six the Day - Night asymmetry selecting neutrino events induced by neutrinos which cross the Earth core. This should

Yuly Billig

In this paper we present the principal construction of the vertex operator representation for toroidal Lie algebras.

A. Pashnev, M. Tsulaia

The local free field theory for Regge trajectory is described in the framework of the BRST - quantization method. The corresponding BRST - charge is constructed with the help of the method of dimensional reduction.

Jnanadeva Maharana

The SL(2,R) invaraint ten dimensional type IIB superstring effective action is compactified on a torus to D spacetime dimensions. The transformation properties of scalar, vector and tensor fields, appearing after the dimensional reduction, are obtained in order to maintain the SL(2,R)} invariance of the reduced effective action. The symmetry of the action en

M. Joyce, M. Shaposhnikov

In the standard model there are charges with abelian anomaly only (e.g. right-handed electron number) which are effectively conserved in the early universe until some time shortly before the electroweak scale. A state at finite chemical potential of such a charge, possibly arising due to asymmetries produced at the GUT scale, is unstable to the generation of

Masayuki Tanimoto

The null surface formalism of GR in three dimensions is presented, and the gauge freedom thereof, which is not just diffeomorphism, is discussed briefly.

J. J. Rodriguez-Nunez, M. Argollo de Menezes

We have postulated a single pole for the self-energy looking for the consequences on the one-particle Green function, G(k,w), in the Hubbard model. We find that G(k,w) satisfies the first two sum rules or moments of Nolting (Z. Physik 225, 25 (1972)) for any values of the two unknown parameters of the self-energy. In order to find these two parameters we hav

G. Curio, D. Lust

We compare the N=1 F-theory compactification of Donagi, Grassi and Witten with modular superpotential - and some closely related models - to dual heterotic models. We read of the F-theory spectrum from the cohomology of the fourfold and discuss on the heterotic side the gauge bundle moduli sector (including the spectral surface) and the necessary fivebranes.

R. S. Chivukula, E. H. Simmons, B. A. Dobrescu

The triviality of the scalar sector of the standard one-doublet Higgs model implies that this model is only an effective low-energy theory valid below some cut-off scale Lambda. We show that the experimental constraint on the amount of custodial symmetry violation implies that the scale Lambda must be greater than of order 7.5 TeV. The underlying high-energy

Nantel Bergeron, Frank Sottile

We illuminate the relation between the Bruhat order on the symmetric group and structure constants (Littlewood-Richardson coefficients) for the cohomology of the flag manifold in terms of its basis of Schubert classes. Equivalently, the structure constants for the ring of polynomials in variables $x_1,x_2,...$ in terms of its basis of Schubert polynomials. W

A. Fix, H. Arenhoevel

Coherent $\eta$ meson photoproduction on $^4$He and $^{12}$C is considered in the near-threshold region. The elementary $\eta$ photoproduction operator includes contributions from the $S_{11}(1535)$ and $D_{13}(1520)$ resonances as well as $t$-channel vector meson exchange and the nucleon pole terms. Due to the suppression of the dominant $S_{11}(1535)$ reso

T. Gorin, F. --M. Dittes, M. Müller, I. Rotter

The distortion of the regular motion in a quantum system by its coupling to the continuum of decay channels is investigated. The regular motion is described by means of a Poissonian ensemble. We focus on the case of only few channels K<10. The coupling to the continuum induces two main effects, due to which the distorted system differs from a chaotic system

Uwe Ritschel, Markus Gerwinski

Using field-theoretical methods and exploiting conformal invariance, we study Casimir forces at tricritical points exerted by long-range fluctuations of the order-parameter field. Special attention is paid to the situation where the symmetry is broken by the boundary conditions (extraordinary transition). Besides the parallel-plate configuration, we also dis

M. E. Pietrzyk

A numerical study of the properties of Gaussian pulses propagating in planar waveguide under the combined effect of positive Kerr-type nonlinearity, diffraction in planar waveguides and anomalous or normal dispersion, is presented. It is demonstrated how the relative strength of dispersion and diffraction, the strength of nonlinearity and the initial spatial

H. Falomir, M. A. Muschietti, E. M. Santangelo, J. Solomin

We explore the use of bi-orthogonal basis for continuous wavelet transformations, thus relaxing the so-called admissibility condition on the analyzing wavelet. As an application, we determine the eigenvalues and corresponding radial eigenfunctions of the Hamiltonian of relativistic Hydrogen-like atoms.

T. Tikkanen, J. Huovelin

The ultrathin X-ray entrance window for the spaceborne spectrometer SIXA was characterised using synchrotron radiation. X-ray absorption fine structure near the absorption edges of the constituting elements (aluminium, carbon, oxygen and nitrogen) was measured. Large scale positional variations were also studied. In addition, the opacity of the window was te

Gilles Montambaux

The form factor for spectral correlations in a diffusive metal is calculated in the presence of several Aharonov-Bohm fluxes. When the fluxes $\phi$ are equal, the correlations are universal functions of $n g^2 \phi$ where $g$ is the dimensionless conductance and $n$ is the number of applied fluxes. This explains recent flux dependence of the correlations fo

M. Dominik

For observed galactic microlensing events only one fit is usually presented, though, especially for a binary lens, several fits may be possible. This has been shown for the MACHO LMC#1 event (Dominik & Hirshfeld 1996). Here I discuss the strong binary lens events OGLE#7 and DUO#2. It is shown that several models with a large variety of parameters are in acco

C. Wetterich

The time development of equal-time correlation functions in quantum mechanics and quantum field theory is described by an exact evolution equation for generating functionals. This permits a comparison between classical and quantum evolution in non-equilibrium systems.

Makoto Kuwabara, Shuji Abe, Yoshiyuki Ono

Interchain hopping of solitons and polarons in polyacetylene is studied by numerical simulation of their motion under an electric field. Use is made of the Su-Schrieffer-Heeger model supplemented with intrachain electron-electron interactions and dopant potentials. We find that charged solitons can hop to the opposite chain by forming bound pairs (bipolarons

V. B. Kopeliovich

The phenomenological consequences of the existence of different local minima in SU(3) configuration space of B=2 skyrmions are discussed.

I. Montvay

The lattice regularization of the Higgs sector of the standard model is summarized. The triviality bound and vacuum instability bound are described. The question of chiral gauge theories is discussed. Some aspects of the numerical simulations of the electroweak phase transition are considered.

Karol Życzkowski

Scattering matrices with block symmetry, which corresponds to scattering process on cavities with geometrical symmetry, are analyzed. The distribution of transmission coefficient is computed for different number of channels in the case of a system with or without the time reversal invariance. An interpolating formula for the case of gradual time reversal sym

Ivan G. Avramidi

The structure of diagonal singularities of Green functions of partial differential operators of even order acting on smooth sections of a vector bundle over a Riemannian man ifold is studied. A special class of operators formed by the products of second-order operators of Laplace type defined with the help of a unique Riemannian metric and a unique bundle co

Oleg A. Soloviev

We discuss two types of deformations of a 2D black hole carrying an electric charge. Type I gives rise to a space-time configuration similar to the one described by McGuigan, Nappi and Yost. Whereas type II results in a space-time configuration which has a rather peculiar geometry.

A. Kull, R. A. Treumann, Hans Böhringer

The statistical mechanical investigation of Violent Relaxation of phase space elements of different densities first derived by Lynden-Bell (1967) is re-examined. It is found that the mass independence of the equations of motion of Violent Relaxation calls for a constraint on the volume of the phase space elements used to formulate the statistical mechanical

N. V. Krasnikov, V. A. Matveev

We review the physics to be investigated at LHC. We also describe the main parameters of CMS and ATLAS detectors.

A. C. Avram, M. Kreuzer, M. Mandelberg, H. Skarke

Recent results on duality between string theories and connectedness of their moduli spaces seem to go a long way toward establishing the uniqueness of an underlying theory. For the large class of Calabi-Yau 3-folds that can be embedded as hypersurfaces in toric varieties the proof of mathematical connectedness via singular limits is greatly simplified by usi

B. Preziosi, G. M. Tino

We analyze the possibility of detecting, with optical methods, particle and photon trajectories predicted by general relativity for a weak spherically-symmetric gravitational field. We discuss the required sensitivities and the possibility of performing specific experiments on the Earth.

Osamu Tsuchiya, Takashi Yamamoto

The boundary effects in the open Hubbard chain with boundary fields are studied. The boundary string solutions of the Bethe ansatz equations that give rise to a wave functions localized at the boundary and exponentially decreasing away from the boundary are provided. In particular, it is shown that the correct ground state of the model at half-filling contai

N. Minkov, S. B. Drenska, P. P. Raychev, R. P. Roussev

A collective vector-boson model with broken SU(3) symmetry, in which the ground state band and the lowest $\gamma$ band belong to the same irreducible representation but are non-degenerate, is applied to several deformed even-even nuclei. The model description of ground and $\gamma$ bands together with the corresponding B(E2) transition probabilities is inve

Hans - Juergen Schmidt

We prove that for non-linear L = L(R), the Lagrangians L and \hat L give conformally equivalent fourth-order field equations being dual to each other. The proof represents a new application of the fact that the operator <D'Alembertian minus R/6> is conformally invariant.

J. F. Gunion

A brief review of muon-collider $s$-channel Higgs physics in the Standard Model and its minimal supersymmetric extension is presented.

D. D. Dixon, P. Kaus, J. Wudka

An effective field approximation, similar to the atomic Thomas-Fermi approach, is proposed for studying non-Abelian gauge theories which includes finite-volume effects. As applications of the formalism the equation of state for an SU(2) gauge theory with massless fermions is obtained. The extensions to realistic situations are briefly discussed.

R. J. Porter, S. Beedoe, R. Bossingham, M. Bougteb

We present measured dielectron production cross sections for Ca+Ca, C+C, He+Ca, and d+Ca reactions at 1.0 A GeV. Statistical uncertainties and systematic effects are smaller than in previous DLS nucleus-nucleus data. For pair mass < 0.35 GeV/c2 : 1) the Ca+Ca cross section is larger than the previous DLS measurement and current model results, 2) the mass spe

I. A. Shushpanov, A. V. Smilga

We study the dependence of quark condensate $\Sigma$ on an external magnetic field. For weak fields, it rises linearly with the field. Pion mass and residue are also shifted so that the Gell-Mann - Oakes - Renner relation is satisfied. In the strong field region, $\Sigma(H) \propto (eH)^{3/2}$.

Klaus Behrndt, Mirjam Cvetic

We found BPS-saturated solutions of M-theory and Type II string theory which correspond to (non-marginally) bound states of p-branes intersecting at angles different from pi/2. These solutions are obtained by starting with a BPS marginally bound (orthogonally) intersecting configurations of two p-branes (e.g, two four-branes of Type II string theory), perfor

I. V. Musatov, A. V. Radyushkin

We analyze effects due to transverse degrees of freedom in QCD calculations of the fundamental hard exclusive amplitude of $\gamma^*\gamma \to \pi^0$ transition. A detailed discussion is given of the relation between the modified factorization approach (MFA) of Sterman et al. and standard factorization (SFA). Working in Feynman gauge, we construct basic buil

Lennox L. Cowie, Esther M. Hu, Antoinette Songaila, Eiichi Egami

A large deep and nearly complete B<24.5 redshift sample is used to measure the change in distribution function of the stellar mass production rate in individual galaxies with redshift. The evolution of the star formation rate distribution with redshift is interpreted in terms of the history of spiral galaxy formation, with the disk component modelled as a si

Christopher D. Carone, Lawrence J. Hall

We consider the neutrino physics of models with a sequentially broken U(2) flavor symmetry. Such theories yield the observed pattern of quark and lepton masses, while maintaining sufficient degeneracies between superparticles of the first two generations to solve the supersymmetric flavor problem. Neutrino mass ratios and mixing angles in these models may di

F. Halzen

This is the summary of a week of very informative presentations on new ways to probe the Universe using gravitational detectors, space and ground based gamma ray telescopes, EeV air shower detectors and neutrino telescopes. Gamma ray bursts and active galaxies were hot theoretical themes in the multi-wavelength discussions.

Ruth Durrer

An introduction to topological defects in cosmology is given. We discuss their possible relevance for structure formation. Especial emphasis is given on the signature of topological defects in the spectrum of anisotropies in the cosmic microwave background. We present simple analytic estimates for the CMB spectrum on large and intermediate scales and compare

H. J. Lubatti, I. J. Muzinich

We consider Higgs-Higgs scattering in a minimal Higgs model with strong coupling which leads to the Higgs as a bound state. The partial wave amplitude is unitarized using general principles of analyticity. We find lambda(m_H)/16pi is approximately 1/2. A Higgs mass of approximately 1 TeV follows from m_H = sqrt{lambda/2} * v (spontaneous symmetry breaking).

K. Intriligator, D. R. Morrison, N. Seiberg

We discuss five-dimensional supersymmetric gauge theories. An anomaly renders some theories inconsistent and others consistent only upon including a Wess-Zumino type Chern-Simons term. We discuss some necessary conditions for existence of nontrivial renormalization group fixed points and find all possible gauge groups and matter content which satisfy them. I

Peter E. Haagensen, Kenneth Johnson

In an abelian gauge theory, the Coulombic potential between two static charges is obtained most directly when a correct separation between gauge-invariant and gauge degrees of freedom is made. This motivates a similar separation in the nonabelian theory. When a careful identification of the Hilbert space is made, along with the proper analyticity requirement

Tarakeshwar Dasgupta, Pran Nath

An analysis of supersymmetric contributions to R_b in supergravity grand unification with non-universal boundary conditions on soft SUSY breaking in the scalar sector is given. Effects on R_b of Planck scale corrections on gaugino masses are also analysed. It is found that there exist regions of the parameter space where positive corrections to R_b of size $

H. Balasin

We generalize previous work on the energy-momentum tensor-distribution of the Kerr geometry by extending the manifold structure into the negative mass region. Since the extension of the flat part of the Kerr-Schild decomposition from one sheet to the double cover develops a singularity at the branch surface we have to take its non-smoothness into account. It

Cristian F. Moukarzel, Phillip M. Duxbury

Using a recently developed algorithm for generic rigidity of two-dimensional graphs, we analyze rigidity and connectivity percolation transitions in two dimensions on lattices of linear size up to L=4096. We compare three different universality classes: The generic rigidity class; the connectivity class and; the generic ``braced square net''(GBSN). We analyz

Jiri Hoogland, Geert Jan van Oldenborgh

We investigated the effect of the light fermion masses on cross sections for e^+e^- into 4 fermions in the Fermion Loop scheme defined in hep-ph/9612260, and approximations to it. The effects are found to be very small, except of course in the collinear region of single W-boson production where the electron mass acts as the cut-off.

Janna J. Levin, John D. Barrow, Emory F. Bunn, Joseph Silk

We investigate the behaviour of light rays in an open universe with a partly periodic horn topology. The geodesics can be solved exactly and the periodic topology creates characteristic new effects in temperature maps of the microwave background. Large flat regions appear in COBE sky maps even when multiple images of astronomical sources are unobservable.

Michael R. Douglas, Hirosi Ooguri, Stephen H. Shenker

We discuss issues concerning M(atrix) theory compactifications on curved spaces. We argue from the form of the graviton propagator on curved space that excited string states do not decouple from the annulus D0-brane $v^4$ amplitude, unlike the flat space case. This argument shows that a large class of quantum mechanical systems with a finite number of degree

J. Adam,, Alfred Stadler, M. T. Peña, Franz Gross

The cross-section for threshold $\pi^0$ production in proton-proton collisions is evaluated in the framework of the covariant spectator description. The negative energy intermediate states are included non-perturbatively and seen to yield a considerably smaller contribution, when compared to perturbative treatments. A family of OBE-models with different off-

S. R. Ignjatovic, L. C. R. Wijewardhana, T. Takeuchi

The analytic continuation by duality (ACD) technique has been used to estimate the electroweak S parameter in technicolor models. In this letter, we investigate the reliability of this method by applying it to some toy models with known spectra. We find that in most instances the technique cannot be trusted to give a reliable result.

T. Takeuchi, L. C. Goonetileke, S. R. Ignjatovic, L. C. R. Wijewardhana

In Nucl. Phys. B391 (1993) 127, the value of the oblique correction parameter S for walking technicolor theories was estimated using a technique called Analytic Continuation by Duality (ACD). We apply the ACD technique to the perturbative vacuum polarization function and find that it fails to reproduce the well known result S=1/6\pi. This brings into questio

M. Valiev, G. W. Fernando

We present a rigorous formulation of generalized Kohn-Sham density-functional theory. This provides a straightforward Kohn-Sham description of many-body systems based not only on particle-density but also on any other observable. We illustrate the formalism for the case of a particle-density based description of a nonrelativistic many-electron system. We obt

Alan H. Durfee

This survey paper discusses five equivalent ways of defining a ``critical point at infinity'' for a complex polynomial of two variables.

Lev N. Shchur, Sergey S. Kosyakov

The probability of simultaneous occurence of at least k spanning clusters has been studied by Monte Carlo simulations on the 2D square lattice at the bond percolation threshold $p_c=1/2$. It is found that the probability of k and more Incipient Spanning Clusters (ISC) has the values $P(k>1) \approx 0.00658(3)$ and $P(k>2) \approx 0.00000148(21)$ provided tha

W. Satuła, D. J. Dean, J. Gary, S. Mizutori

Surfaces of experimental masses of even-even and odd-odd nuclei exhibit a sharp slope discontinuity at N=Z. This cusp (Wigner energy), reflecting an additional binding in nuclei with neutrons and protons occupying the same shell model orbitals, is usually attributed to neutron-proton pairing correlations. A method is developed to extract the Wigner term from

Tom O'Hara, Janyce Wiebe, Karen Payne

Human annotation of natural language facilitates standardized evaluation of natural language processing systems and supports automated feature extraction. This document consists of instructions for annotating the temporal information in scheduling dialogs, dialogs in which the participants schedule a meeting with one another. Task-oriented dialogs, such as t

Unal Goktas, Willy Hereman

A new algorithm for the symbolic computation of polynomial conserved densities for systems of nonlinear evolution equations is presented. The algorithm is implemented in Mathematica. The program condens.m automatically carries out the lengthy symbolic computations for the construction of conserved densities. The code is tested on several well-known partial d

David W. Hogg, Michael A. Pahre, James K. McCarthy, Judith G. Cohen

Ground-based counts and colors of faint galaxies in the U and R bands in one field at high Galactic latitude are presented. Integrated over flux, a total of 1.2x10^5 sources per square degree are found to U=25.5 mag and 6.3x10^5 sources per square degree to R=27 mag, with d log N/dm ~ 0.5 in the U band and d log N/dm ~ 0.3 in the R band. Consistent with thes

Sergio M. C. V. Goncalves, Ian G. Moss

It is shown that there exists a range of parameters in which gravitational collapse with a spherically symmetric massive scalar field can be treated as if it were collapsing dust. This implies a criterion for the formation of black holes depending on the size and mass of the initial field configuration and the mass of the scalar field.

J. P. Gauntlett, G. W. Gibbons, G. Papadopoulos, P. K. Townsend

Generalized membrane solutions of D=11 supergravity, for which the transverse space is a toric hyper-K{\" a}hler manifold, are shown to have IIB duals representing the intersection of parallel 3-branes with 5-branes whose orientations are determined by their $Sl(2;\bZ)$ charge vectors. These IIB solutions, which generically preserve 3/16 of the supersymmetry

Kimyeong Lee

We review our recent work on the BPS magnetic monopoles and its relation to the electromagnetic duality in the N=4 supersymmetric Yang-Mills systems with an arbitrary gauge group. The gauge group can be maximally or partially broken. The low energy dynamics of the massive and massless magnetic monopoles are approximated by the moduli space metric. We emphasi

Cumrun Vafa

In this set of lectures I review recent developments in string theory emphasizing their non-perturbative aspects and their recently discovered duality symmetries. The goal of the lectures is to make the recent exciting developments in string theory accessible to those with no previous background in string theory who wish to join the research effort in this a

Ralph Blumenhagen, Michael Flohr

We study orbifolds of (0,2) models and their relation to (0,2) mirror symmetry. In the Landau-Ginzburg phase of a (0,2) model the superpotential features a whole bunch of discrete symmetries, which by quotient action lead to a variety of consistent (0,2) vacua. We study a few examples in very much detail. Furthermore, we comment on the application of (0,2) m

A. B. Henriques, L. E. Mendes, R. G. Moorhouse

This paper evaluates and compares the gravitational wave and density perturbation contributions to the cosmic microwave background radiation, on the basis of the same power law inflationary model. The inflation to radiation transition is treated as instantaneous, but a model is constructed to allow for a smooth transition from the radiation to the matter dom

H. S. Park, E. Ables, D. L. Band, S. D. Barthelmy

The Gamma-Ray Optical Counterpart Search Experiment (GROCSE) presents new experimental upper limits on the optical flux from gamma-ray bursts (GRBs). Our experiment consisted of a fully-automated very wide-field opto-electronic detection system that imaged locations of GRBs within a few seconds of receiving trigger signals provided by BATSE's real-time burst

Gabor Takacs

The R-matrix of the U_q(d_4(3)) algebra is constructed in the 8-dimensional fundamental representation. Using this result an exact S-matrix is conjectured for the imaginary coupled g_2(1) affine Toda field theory, the structure of which is found to be very similar to the previously investigated S-matrix of d_4(3) Toda theory. It is shown that this S-matrix i

M. Svec

The paper has been withdrawn

M. Svec

The paper has been withdrawn

Yan Chen, Shi-Jie Xiong, S. N. Evangelou

We obtain exact analytical expressions for the electronic transport through a multi-channel system, also with an applied magnetic field. The geometrical structure of the electrodes is found to cause a splitting of the conduction band into many subbands, depending on the number and the length of the chains and the conductance approaches zero when the chain nu

Grant Bazán, David Arnett

By direct hydrodynamic simulation, using the Piecewise Parabolic Method (PPM) code PROMETHEUS, we study the properties of a convective oxygen burning shell in a SN 1987A progenitor star prior to collapse. The convection is too heterogeneous and dynamic to be well approximated by one-dimensional diffusion-like algorithms which have previously been used for th

Rudolf A. Roemer, Michael Schreiber

In response to a recent Comment by Frahm et al. regarding our Letter [Phys. Rev. Lett. {\bf 78}, 515 (1997)], we point out that no ``consistent picture'' exists for the enhancement of the localization length $\lambda_2$ for two interacting particles (TIP) proposed previously by Shepelyansky. In fact there are at least 3 different proposals for the dependence

E. Kh. Akhmedov, A. Lanza, D. W. Sciama

Young pulsars are known to exhibit large space velocities, up to $10^3$ km/s. We propose a new mechanism for the generation of these large velocities based on an asymmetric emission of neutrinos during the supernova explosion. The mechanism involves the resonant spin-flavour precession of neutrinos with a transition magnetic moment in the magnetic field of t

S. A. Larin, T. van Ritbergen, J. A. M. Vermaseren

We present the analytical calculation in perturbative Quantum Chromodynamics of the (alpha_s)^3 contribution to the Ellis-Jaffe sum rule for the structure function g1 of polarized deep inelastic lepton-nucleon scattering.

C. D. D. Neumann

This paper investigates the algebraic structure that exists on perturbative BPS-states in the superstring, compactified on the product of a circle and a Calabi-Yau fourfold. This structure was defined in a recent article by Harvey and Moore. It shown that for a toroidal compactification this algebra is related to a generalized Kac-Moody algebra. The BPS-alge

Alexander M. Chebotarev

We show a new remarkable connection between the symmetric form of a quantum stochastic differential equation (QSDE) and the strong resolvent limit of Schr\"odinger equations in Fock space: the strong resolvent limit is unitary equivalent to QSDE in the adapted (or Ito) form, and the weak limit is unitary equivalent to the symmetric (or Stratonovich) form of

M. Novello, V. A. De Lorenci, E. Elbaz

In this paper we present a new model for a gauge field theory such that self-interacting spin-one particles can be confined in a compact domain. The necessary conditions to produce the confinement appear already in the properties of the eikonal structure generated by the particular choice of the dynamics. The gluons do not follow along Minkowski null cone an

Alexander A. Vlasov

The instability of "physical" preaccelerative solution of the Lorentz-Dirac equation is explicitly shown

F. Manghi, V. Bellini, C. Arcangeli

We present a method which allows to include narrow-band correlation effects into the description of both valence and core states and we apply it to the prototypical case of nickel. The results of an ab-initio band calculation are used as input mean-field eigenstates for the calculation of self-energy corrections and spectral functions according to a three-bo

J. Fuchs

We construct a vertex operator realization for the simple current primary fields of WZW theories which are based on simply laced affine Lie algebras g. This is achieved by employing an embedding of the integrable highest weight modules of g into the Fock space for a bosonic string compactified on the weight lattice of g. Our vertex operators are universal in

J. Fuchs

This is an introduction to the basic ideas and to a few further selected topics in conformal quantum field theory and in the theory of Kac-Moody algebras.

R. D. Blum, T. M. Ramond, P. S. Conti, D. F. Figer

We present a new spectroscopic classification for OB stars based on H-band (1.5 micron to 1.8 micron) observations of a sample of stars with optical spectral types. Our initial sample of nine stars demonstrates that the combination of He I 1.7002 micron and H Brackett series absorption can be used to determine spectral types for stars between about O4 and B7

Fernando Atrio-Barandela, Sacha Davidson

We discuss the viability of a light particle ($\sim 30$ eV neutrino) with strong self-interactions as a dark matter candidate. The interaction prevents the neutrinos from free-streaming during the radiation dominated regime so galaxy sized density perturbations can survive. Smaller scale perturbations are damped due to neutrino diffusion. We calculate the po

Andrew J. Bordner

We consider a 1+1 dimensional field theory which contains both a complex fermion field and a real scalar field. We then construct a unitary operator that, by a similarity transformation, gives a continuum of equivalent theories which smoothly interpolate between the massive Thirring model and the sine-Gordon model. This provides an implementation of smooth b

Takeshi Nakanishi, Tomi Ohtsuki, Tohru Kawarabayashi

Diffusion of electrons in a two-dimensional system with time-dependent random potentials is investigated numerically. The correction to the conductivity due to inelastic scatterings by oscillating potentials is shown to be a universal function of the frequency $\omega$, which is consistent with the weak localization prediction $(e^2)/(3\pi^2 \hbar) log \omeg

Parongama Sen

We investigate phase transitions in the Ising model and the ANNNI model in transverse field using the interface approach. The exact result of the Ising chain in a transverse field is reproduced. We find that apart from the interfacial energy, there are two other response functions which show simple scaling behaviour. For the ANNNI model in a transverse field

Georg Goeppert, Xiaohui Wang, Hermann Grabert

The linear conductance of a tunnel junction in series with an ohmic resistor is determined in the high temperature limit. The tunneling current is treated nonperturbatively by means of path integral techniques. Due to quantum effects the conductance is smaller than the classical series conductance. The reduction factor is found to be nonanalytic in the envir

Thomas Vojta, Rudolf A. Roemer, Michael Schreiber

We reinvestigate the validity of mapping the problem of two onsite interacting particles in a random potential onto an effective random matrix model. To this end we first study numerically how the non-interacting basis is coupled by the interaction. Our results indicate that the typical coupling matrix element decreases significantly faster with increasing s

M. Franco, L. Brey

We study the electric and magnetic properties of the edge of a two-dimensional electron gas in presence of a magnetic field and at filling factor unity. The existence of a spin textured edge is proved as a function of the Zeeman coupling and of the smoothness of the confining potential. We also calculate the low energy excitation of the spin textured phase.

C. Panagiotakopoulos

We construct a hybrid inflationary model associated with the superheavy scale of supersymmetric grand unified theories in which the inflaton potential is provided entirely by canonical supergravity. We find that the spectrum of adiabatic density perturbations is characterized by a strongly varying spectral index which is considerably larger than unity. Moreo

P. H. Chankowski, Pokorski

After reviewing briefly the upper bounds on the mass of the lightest Higgs boson in the most general unconstrained minimal supersymmetric extension of the Standard Model, we discuss various arguments which reduce the parameter space of the model and give stronger predictions for $M_{h^0}$. First, the constraints from the presently available experimental data

Silvia Mollerach, Sabino Matarrese

This paper presents a complete analysis of the effects of second order gravitational perturbations on Cosmic Microwave Background anisotropies, taking explicitly into account scalar, vector and tensor modes. We also consider the second order perturbations of the metric itself obtaining them, for a universe dominated by a collision-less fluid, in the Poisson

M. Toller

This paper gives a representation of the most general positive operator valued measure in Minkowski space-time, covariant with respect to the Poincare' group. It provides the correct mathematical description of the space-time coordinates of a quantum event, described by a quantum object with suitable properties. It is known that these coordinates cannot be r

W. Cassing

The production and propagation of mesons ($\pi, \eta, \rho, \omega, \Phi, K, \bar{K}, J/\Psi$) in proton-nucleus and nucleus-nucleus collisions from 1 - 200 GeV/u is studied within the covariant transport approach HSD, which explicitly allows to investigate selfenergy effects of the hadrons at finite baryon density. Whereas the experimental pion and $K^+$ sp

Frederic Mila, Karlo Penc

The interpretation of the k dependent spectral functions of the one-dimensional, infinite U Hubbard model obtained by using the factorized wave-function of Ogata and Shiba is revisited. The well defined feature which appears in addition to low energy features typical of Luttinger liquids, and which, close to the Fermi energy, can be interpreted as the shadow

Andrei Komnik, Reinhold Egger, Alexander O. Gogolin

We report the exact calculation of the Fermi-edge singularity exponent for correlated electrons in one dimension (Luttinger liquid). Focusing on the special interaction parameter g=1/2, the asymptotic long-time behavior can be obtained using the Wiener-Hopf method. The result confirms the previous assumption of an open boundary fixed point. In addition, a dy