arXiv papers from June 1999

S. Carlip

On a manifold with boundary, the constraint algebra of general relativity may acquire a central extension, which can be computed using covariant phase space techniques. When the boundary is a (local) Killing horizon, a natural set of boundary conditions leads to a Virasoro subalgebra with a calculable central charge. Conformal field theory methods may then b

Re'em Sari

We investigate the polarization and proper motion expected in a beamed Gamma-Ray Burst's ejecta. We find that even if the magnetic field has well defined orientation relative to the direction of motion of the shock, the polarization is not likely to exceed 20%. Taking into account the dynamics of beamed ejecta we find that the polarization rises and decays w

Davide Turcato, Paul McFetridge, Fred Popowich, Janine Toole

We present an approach to Machine Translation that combines the ideas and methodologies of the Example-Based and Lexicalist theoretical frameworks. The approach has been implemented in a multilingual Machine Translation system.

Luis P. Chimento, Alejandro S. Jakubi, Diego Pavon

Starting from the inhomogeneous shear--free Nariai metric we show, by solving the Einstein--Klein--Gordon field equations, how a self--interacting scalar field plus a material fluid, a variable cosmological term and a heat flux can drive the universe to its currently observed state of homogeneous accelerated expansion. A quintessence scenario where power-law

Duiliu-Emanuel Diaconescu, Jaume Gomis

We study the D-brane spectrum of N=2 string orbifold theories using the boundary state formalism. The construction is carried out for orbifolds with isolated singularities, non-isolated singularities and orbifolds with discrete torsion. Our results agree with the corresponding K-theoretic predictions when they are available and generalize them when they are

A. J. Baltz

Some recent theoretical results on coherent electromagnetic processes in ultrarelativistic heavy ion reactions are surveyed.

Chris Simpson, Peter Eisenhardt, Lee Armus, Arati Chokshi

We present ground-based images of the z=1.824 radio galaxy 3C 256 in the standard BVRIJHK filters and an interference filter centered at 8800A, a Hubble Space Telescope image in a filter dominated by Ly-alpha emission (F336W), and spectra covering rest-frame wavelengths from Ly-alpha to [O III] 5007. Together with published polarimetry observations, we use t

Toshihiko Ono

This paper proposes a basic theory on physical reality, and a new foundation for quantum mechanics and classical mechanics. It does not only solve the problem of the arbitrariness on the operator ordering for the quantization procedure, but also clarifies how the classical-limit occurs. It further compares the new theory with the known quantization methods,

B. Lake, G. Aeppli, T. E. Mason, A. Schroder

A notable aspect of high-temperature superconductivity in the copper oxides is the unconventional nature of the underlying paired-electron state. A direct manifestation of the unconventional state is a pairing energy - that is, the energy required to remove one electron from the superconductor - that varies (between zero and a maximum value) as a function of

J. Ricardo G. de Mendonça

We calculated some of the critical exponents of the directed percolation universality class through exact numerical diagonalisations of the master operator of the one-dimensional basic contact process. Perusal of the power method together with finite-size scaling allowed us to achieve a high degree of accuracy in our estimates with relatively little computat

A. Ashikhmin, A. Barg, E. Knill, S. Litsyn

In Part II we show that there exist quantum codes whose probability of undetected error falls exponentially with the length of the code and derive bounds on this exponent.The lower (existence) bound for stabilizer codes is proved by a counting argument for classical self-orthogonal quaternary codes. Upper bounds for any quantum codes are proved by linear pro

Deog Ki Hong, Mannque Rho, Ismail Zahed

In the color-flavor-locked (CFL) phase of the QCD superconductor we show that baryons behave as qualitons (called "superqualitons") with quantum numbers $B=(1 {\rm mod} 2)/3$, S=1/2 and Y=B. An intriguing possibility implied by this identification is that light baryonic modes in the form of superqualitons could be excited below the (color) superconducting ga

NA49 Collaboration, A. M. Poskanzer, S. A. Voloshin

New data with a minimum bias trigger for 158 GeV/nucleon Pb + Pb have been analyzed. Directed and elliptic flow as a function of rapidity of the particles and centrality of the collision are presented. The centrality dependence of the ratio of elliptic flow to the initial space elliptic anisotropy is compared to models.

N. Read, Dmitry Green

We analyze pairing of fermions in two dimensions for fully-gapped cases with broken parity (P) and time-reversal (T), especially cases in which the gap function is an orbital angular momentum ($l$) eigenstate, in particular $l=-1$ (p-wave, spinless or spin-triplet) and $l=-2$ (d-wave, spin-singlet). For $l\neq0$, these fall into two phases, weak and strong p

Aaron K. Grant, Zurab Kakushadze

In theories with TeV scale quantum gravity there is a logical possibility where the electroweak Higgs can be a fourth generation slepton. Despite maximal supersymmetry breaking such a scenario turns out to be tightly constrained, and might be testable already at present collider experiments. Also, a light Higgs is no longer a prediction of supersymmetry.

C. Gundlach

Continuously self-similar (CSS) solutions for the gravitational collapse of a spherically symmetric perfect fluid, with the equation of state p=kappa rho, with 0<kappa<1 a constant, are constructed numerically and their linear perturbations, both spherical and nonspherical, are investigated. The l=1 axial perturbations admit an analytical treatment. All othe

E. I. Sorokina, S. I. Blinnikov, O. S. Bartunov

The calculations of the light curves of thermonuclear supernovae are carried out by a method of multi-group radiation hydrodynamics. The effects of spectral lines and expansion opacity are taken into account. The predictions for UBVI fluxes are given. The values of rise time for B and V bands found in our calculations are in good agreement with the observed

T. Appelquist, P. S. Rodrigues da Silva, F. Sannino

We examine the possibility that the physical spectrum of a vector-like gauge field theory exhibits an enhanced global symmetry near a chiral phase transition. A transition from the Goldstone phase to the symmetric phase is expected as the number of fermions N_f is increased to some critical value. Various investigations have suggested that a parity-doubled s

Michael Catanese, Trevor C. Weekes

We present a review of the current status of very high energy gamma-ray astronomy. The development of the atmospheric Cherenkov imaging technique for ground-based gamma-ray astronomy has led to a rapid growth in the number of observatories. The detection of TeV gamma rays from Active Galactic Nuclei was unexpected and is providing new insights into the emiss

J. A. Eilek, J. C. Weatherall

In situ particle acceleration is probably occuring in cluster radio haloes. This is suggested by the uniformity and extent of the haloes, given that spatial diffusion is slow and that radiative losses limit particle lifetimes. Stochastic acceleration by plasma turbulence is the most likely mechanism. Alfven wave turbulence has been suggested as the means of

Karl Gebhardt, Markus Kissler-Patig

We have compiled data for the globular cluster systems of 50 galaxies from the HST WFPC2 archive, of which 43 are type S0 or earlier. In this paper, we present the data set and derive the V-I color distributions. We derive the first four moments of the color distributions, as well as a measure for their non--unimodality. The number of globular clusters in ea

T. Mart, C. Bennhold

New SAPHIR p(gamma,K+)Lambda total cross section data show a resonance structure at a total c.m. energy around 1900 MeV. We investigate this feature with an isobar model and find that the structure can be well explained by including a new D_{13} resonance at 1895 MeV. Such a state has been predicted by a relativistic quark model at 1960 MeV with significant

Michael Dine, Yuri Shirman

There are only a small number of ideas for stabilizing the moduli of string theory. One of the most appealing of these is the racetrack mechanism, in which a delicate interplay between two strongly interacting gauge groups fixes the value of the coupling constant. In this note, we explore this scenario. We find that quite generally, some number of discrete t

C. Destri, E. Manfredini

The $\lambda \phi^4$ model in a finite volume is studied in the infinite $N$ limit and within a non-gaussian Hartree-Fock approximation both at equilibrium and out of equilibrium, with particular attention to certain fundamental features of the broken symmetry phase. The numerical solution of the dynamical evolution equations show that the zero-mode quantum

Q. Y. Liu

The solar neutrino spectrum measured by the Super-Kamiokande shows an excess in high energy bins, which may be explained by vacuum oscillation solution or $hep$ neutrino effect. Here we reconsider an uncertainty of the data caused by the tail of the energy resolution function. Events observed at energy higher than 13.5 MeV are induced by the tail of the reso

Bartolo Luque, Ricard V. Sole

A new order parameter approximation to Random Boolean Networks (RBN) is introduced, based on the concept of Boolean derivative. A statistical argument involving an annealed approximation is used, allowing to measure the order parameter in terms of the statistical properties of a random matrix. Using the same formalism, a Lyapunov exponent is calculated, allo

Hidetoshi Awata, Miao Li, Djordje Minic, Tamiaki Yoneya

We present several non-trivial examples of the three-dimensional quantum Nambu bracket which involve square matrices or three-index objects. Our examples satisfy two fundamental properties of the classical Nambu bracket: they are skew-symmetric and they obey the Fundamental Identity. We contrast our approach to the existing literature on the quantum deformat

H. C. Rosu

First Internet graduate course on Classical Mechanics in Spanish (Castellano). This is about 80% of the material I covered during the January-June 1999 semester at IFUG in the Mexican city of Leon. English and Romanian versions are in (slow) progress and hopefully will be arXived. For a similar course on Quantum Mechanics, see physics/9808031

Fermilab Experiment E791 Collaboration, E. M. Aitala

We report the results of a search for flavor-changing neutral current, lepton-flavor violating, and lepton-number violating decays of D+, Ds, and D0 mesons (and their antiparticles) into modes containing muons and electrons. Using data from Fermilab charm hadroproduction experiment E791, we examine the pi,l,l and K,l,l decay modes of D+ and Ds and the l+l- d

P. Ramadevi

Three-String junctions are allowed configurations in II B string theory which preserve one-fourth supersymmetry. We obtain the 11-dimensional supergravity solution for curved membranes corresponding to these three-string junctions.

Krzysztof Kurdyka, Tadeusz Mostowski, Adam Parusinski

Let x(t) be a trajectory of the gradient of a real analytic function and suppose that x_0 is a limit point of x(t). We prove the gradient conjecture of R. Thom which states that the secants of x(t) at x_0 have a limit. Actually we show a stronger statement: the radial projection of x(t) from x_0 onto the unit sphere has finite length.

Juan Garcia-Bellido

Cosmology is nowadays going through a true revolution in the quantity and quality of observations that are capable of providing crucial information about the origin and evolution of the universe. In the first years of the next millenium we will have, for the first time in the history of cosmology, a precise knowledge about a handful of parameters that determ

Sergei A. Klioner, Michael H. Soffel

Starting from the global parametrized post-Newtonian (PPN) reference system with two PPN parameters $\gamma$ and $\beta$ we consider a space-bounded subsystem of matter and construct a local reference system for that subsystem in which the influence of external masses reduces to tidal effects. Both the metric tensor of the local PPN reference system in the f

Paul Federbush

Some generalized BRS transformations are developed for the pure Yang-Mills theory, and a form of quantum gravity. Unlike the usual BRS transformations: these are nonlocal; may be infinite formal power series in the gauge fields; and do not leave the action invariant, but only the product exp(-S) with the Jacobian. Similar constructions should exist for many

Ziqiang Wang, Matthew P. A. Fisher, S. M. Girvin, J. T. Chalker

We study the influence of short-range electron-electron interactions on scaling behavior near the integer quantum Hall plateau transitions. Short-range interactions are known to be irrelevant at the renormalization group fixed point which represents the transition in the non-interacting system. We find, nevertheless, that transport properties change disconti

M. Bureau, K. C. Freeman, D. W. Pfitzner, G. R. Meurer

NGC 2915 is a blue compact dwarf galaxy with a very extended HI disk showing a short central bar and extended spiral arms, both reaching far beyond the optical component. We use Tremaine & Weinberg (1984) method to measure the pattern speed of the bar from HI radio synthesis data. Our measurements yield a pattern speed of 0.21+/-0.06 km/s/arcsec (8.0+/-2.4 k

Andrea D'Agnolo, Pierre Schapira

The micro-support of sheaves is a tool to describe local propagation results. A natural problem is then to give sufficient conditions to get global propagation results from the knowledge of the micro-support. This is the aim of this paper. As an application, we consider the problem of global existence for solutions to hyperbolic systems (in the hyperfunction

J. Millard, D. Branch, E. Baron, K. Hatano

Synthetic spectra generated with the parameterized supernova synthetic-spectrum code SYNOW are compared to observed photospheric-phase spectra of the Type Ic supernova 1994I. The observed optical spectra can be well matched by synthetic spectra that are based on the assumption of spherical symmetry. We consider the identification of the infrared absorption f

Fabio Cardarelli, Silvano Simula

The neutron charge form factor GEn(Q**2) is investigated within a constituent quark model formulated on the light-front. It is shown that, if the quark initial motion is neglected in the Melosh rotations, the Dirac neutron form factor F1n(Q**2)$ receives a relativistic correction which cancels exactly against the Foldy term in GEn(Q**2), as it has been recen

Jiri Chyla, Marek Tasevsky

Interactions of virtual photons are analyzed in terms of their parton distribution functions. It is shown that the concept of parton distribution functions is phenomenologically very useful even for highly virtual photonds involved in hard collisions. The role of the longitudinal photons for proper interpretation of the data on jet cross--sections in the reg

O. Benichou, A. M. Cazabat, M. Moreau, G. Oshanin

We study the dynamics of a tracer particle, which performs a totally directed random walk in an adsorbed monolayer composed of mobile hard-core particles undergoing continuous exchanges with a vapour phase. In terms of a mean-field-type approach, based on the decoupling of the tracer-particle-particle correlation functions into the product of pairwise, trace

J. E. Sonier, J. H. Brewer, R. F. Kiefl, D. A. Bonn

Muon spin rotation measurements of the magnetic field distribution in the vortex state of the oxygen deficient high-Tc superconductor YBa{2}Cu{3}O{6.60} reveal a vortex-lattice melting transition at much lower temperature than that in the fully oxygenated material. The transition is best described by a model in which adjacent layers of ``pancake'' vortices d

J. E. Sonier, J. H. Brewer, R. F. Kiefl, G. D. Morris

A novel high magnetic field (8 T) spectrometer for muon spin rotation has been used to measure the temperature dependence of the in-plane magnetic penetration depth in YBa2Cu3O6.95. At low H and low T, the penetration depth exhibits the characteristic linear T dependence associated with the energy gap of a d_x^2-y^2-wave superconductor. However, at higher fi

L. Baudis, H. V. Klapdor-Kleingrothaus

The potential of the GENIUS proposal to measure the spectrum of low energy solar neutrinos in real time is studied. The detection reaction is elastic neutrino-electron scattering. The energy resolution for detecting the recoil electrons is about 0.3 %, the energy threshold is a few keV. The expected number of events for a target of one ton of natural germani

Bodo Huckestein

The temperature and scale dependence of resistivities in the standard scaling theory of the integer quantum Hall effect is discussed. It is shown that recent experiments, claiming to observe a discrepancy with the global phase diagram of the quantum Hall effect, are in fact in agreement with the standard theory. The apparent low-field transition observed in

Florin P. Boca, Paul Goldstein

It is shown that Voiculescu's toplogical entropy for the canonical endomorphism of a simple Cuntz-Krieger algebra O_A equals the logarithm of the spectral radius of A.

Matthias Opel, Francesca Venturini, Rudi Hackl, Helmuth Berger

We present results of Raman scattering experiments in differently doped Bi-2212 single crystals. Below Tc the spectra show pair-breaking features in the whole doping range. The low frequency power laws confirm the existence of a $d_{x^2-y^2}$-wave order parameter. In the normal state between Tc and T* = 200K we find evidence for a pseudogap in B2g symmetry.

Dorit Aharonov, Michael Ben-Or

This paper proves the threshold result, which asserts that quantum computation can be made robust against errors and inaccuracies, when the error rate, $\eta$, is smaller than a constant threshold, $\eta_c$. The result holds for a very general, not necessarily probabilistic noise model, for quantum particles with any number of states, and is also generalized

N. Grandi, R. L. Pakman, F. A. Schaposnik, G. Silva

We present dyon solutions to an SU(2) Dirac-Born-Infeld (DBI) gauge theory coupled to a Higgs triplet. We consider different non-Abelian extensions of the DBI action and study the resulting solutions numerically, comparing them with the standard Julia-Zee dyons. We discuss the existence of a critical value of $\beta$, the Born-Infeld absolute field parameter

Robin Hartshorne, Enrico Schlesinger

We study locally Cohen-Macaulay curves in projective three-space which are contained in a double plane 2H, thus completing the classification of curves lying on surfaces of degree two. We describe the irreducible components of the Hilbert schemes of locally Cohen-Macaulay curves in 2H of given degree and arithmetic genus. We show that these Hilbert schemes a

H. Voss, M. J. Bünner, M. Abel

We present a method for the identification of continuous, spatiotemporal dynamics from experimental data. We use a model in the form of a partial differential equation and formulate an optimization problem for its estimation from data. The solution is found as a multivariate nonlinear regression problem using the ACE-algorithm. The procedure is successfully

M. J. Bünner, Th. Meyer, A. Kittel, J. Parisi

We present a method for time series analysis of both, scalar and nonscalar time-delay systems. If the dynamics of the system investigated is governed by a time-delay induced instability, the method allows to determine the delay time. In a second step, the time-delay differential equation can be recovered from the time series. The method is a generalization o

M. E. Fouladvand, H. -W. Lee

Within the formalism of matrix product ansatz, we study a two-species asymmetric exclusion process with backward and forward site-ordered sequential update. This model, which was originally introduced with the random sequential update, describes a two-way traffic flow with a dynamic impurity and shows a phase transition between the free flow and traffic jam.

S. Griffiths, D. A. Ross

We consider the flavour non-singlet Reggeon within the context of perturbative QCD. This consists of ladders built out of ``reggeized'' quarks. We propose a method for the numerical solution of the integro-differential equation for the amplitude describing the exchange of such a Reggeon. The solution is known to have a sharp rise at low values of Bjorken-x w

C. P. Constantinidis, J. C. Fabris, R. G. Furtado, M. Picco

We study cosmological scenarios resulting from effective actions in four dimensions which are, under some assumptions, connected with multidimensional, supergravity and string theories. These effective actions are labeled by the parameters $\omega$, the dilaton coupling constant, and $n$ which establishes the coupling between the dilaton and a scalar field o

M. Bando, T. Kugo, T. Noguchi, K. Yoshioka

In higher dimensional models where the gauge and gravity fields live in the bulk and the matter fields only in a brane, we point out the importance of the brane (transverse) coordinate modes, which are the Nambu-Goldstone bosons appearing as a result of spontaneous breaking of the translation symmetry. The brane recoil effect suppresses the couplings of high

The OPAL Collaboration, G. Abbiendi et al

The helicity density matrix elements rho[00] of rho(770)+- and omega(782) mesons produced in Z decays have been measured using the OPAL detector at LEP. Over the measured meson energy range, the values are compatible with 1/3, corresponding to a statistical mix of helicity -1, 0 and +1 states. For the highest accessible scaled energy range 0.3 < x_E < 0.6, t

Matthias Opel, Martin Götzinger, Christian Hoffmann, Ralf Nemetschek

We present results of electronic Raman-scattering experiments in differently doped Y-123. In B2g symmetry, an analysis of the data in terms of a memory function approach is presented and dynamical relaxation rates $\Gamma(\omega,T)$ and mass-enhancement factors $1+\lambda(\omega,T)$ for the carriers are obtained. Starting from temperatures T > 180K, $\Gamma(

Alexei Yung

We study the mechanism of confinement via formation of Abrikosov-Nielsen-Olesen vortices on the Higgs branch of N=2 supersymmetric SU(2) gauge theory with massive fundamental matter. Higgs branch represents a limiting case of superconductor of type I with vanishing Higgs mass. We show that in this limit vortices still exist although they become logarithmical

T. Dudok de Wit, V. V. Krasnosel'skikh, M. Dunlop, H. Luehr

A framework is described for estimating Linear growth rates and spectral energy transfers in turbulent wave-fields using two-point measurements. This approach, which is based on Volterra series, is applied to dual satellite data gathered in the vicinity of the Earth's bow shock, where Short Large Amplitude Magnetic Structures (SLAMS) supposedly play a leadin

Atalay Karasu

The bi-Hamiltonian structure of original Hirota-Satsuma system proposed by Roy based on a modification of the bi-Hamiltonian structure of Ito system is incorrect.

T. Dudok de Wit

An expression is proposed for determining the error caused on entropy estimates by finite sample effects. This expression is based on the Ansatz that the ranked distribution of probabilities tends to follow an empirical Zipf law.

R. S. Furuya, Y. Kitamura, M. Saito, R. Kawabe

We conducted VLA observations at 0".06 resolution of the 22 GHz water masers toward the Class 0 source S106 FIR (d=600 pc; 15" west of S106-IRS4) on two epochs separated by ~3 months. Two compact clusters of the maser spots were found in the center of the submillimeter core of S106 FIR. The separation of the clusters was ~80 mas (48 AU) along P. A. = 70 degr

Tamar Kustanovich, Zeev Olami

The interrelations between short range structural and elastic aspects in glasses and glass forming liquids pose important and yet unresolved questions. In this paper these relations are analyzed for mono-atomic glasses and stressed liquids with a short range repulsive-attractive pair potentials. Strong variations of the local pressure are found even in a zer

Yoshiaki Mizuno, Takami Tohyama, Sadamichi Maekawa

We examine two-spin (2S) and cyclic four-spin (4S) magnetic interactions in insulating ladder and two-dimensional (2D) cuprates. By a comparison of eigenstates between d-p and Heisenberg models, we evaluate magnitudes of these interactions. We find that the 4S interaction is $\sim$10% of nearest neighboring 2S interaction, and a diagonal 2S interaction is co

C. Grupen

In this review the basic interaction mechanisms of charged and neutral particles are presented. The ionization energy loss of charged particles is fundamental to most particle detectors and is therefore described in more detail. The production of electromagnetic radiation in various spectral ranges leads to the detection of charged particles in scintillation

W. Buchmüller

The large rapidity gap events, observed at HERA, have changed considerably our physical picture of deep inelastic scattering during the past years. We review the present theoretical understanding of diffractive DIS with emphasis on the close relation to inclusive DIS. This includes success and limitations of the leading twist description, the connection betw

L. V. Bravina, E. E. Zabrodin, M. I. Gorenstein, S. A. Bass

The assumption of local equilibrium in relativistic heavy ion collisions at energies from 10.7 AGeV (AGS) up to 160 AGeV (SPS) is checked in the microscopic transport model. Dynamical calculations performed for a central cell in the reaction are compared to the predictions of the thermal statistical model. We find that kinetic, thermal and chemical equilibra

A. Gehrmann-De Ridder

We present the results of a calculation of deep inelastic electron-photon scattering at a linear collider for very high virtuality of the intermediate gauge boson up to NLO in perturbative QCD. The real photon is produced unpolarized via the Compton back scattering of laser light of the incoming beam. For $Q^2$ values close to the masses squared of the Z and

L. Pietronero, R. Cafiero, A. Gabrielli

In this lecture we present an overview of the physics of irreversible fractal growth process, with particular emphasis on a class of models characterized by {\em quenched disorder}. These models exhibit self-organization, with critical properties developing spontaneously, without the fine tuning of external parameters. This situation is different from the us

R. Crespo, R. C. Johnson

This work addresses the question of precisely what features of few body models of halo nuclei are probed by elastic scattering on protons at high centre-of-mass energies. Our treatment is based on a multiple scattering expansion of the proton-projectile transition amplitude in a form which is well adapted to the weakly bound cluster picture of halo nuclei. I

Francesc Planas-Vilanova

For two ideals $I$ and $J$ of a noetherian ring, we characterize, in terms of the vanishing of Tor modules, when the associated graded ring of the sum $I+J$ is isomorphic to the tensor product of the associated graded ring of $I$ and the associated graded ring of $J$. It is shown that the relation type of the tensor product of two standard algebras is bounde

Guinevere Kauffmann, Martin Haehnelt

We incorporate a simple scheme for the growth of supermassive black holes into semi-analytic models that follow the formation and evolution of galaxies in a cold dark matter dominated Universe. We assume that supermassive black holes are formed and fuelled during major mergers. If two galaxies of comparable mass merge, their central black holes coalesce and

Carsten Henkel, Sierk Poetting, Martin Wilkens

We derive the life time and loss rate for a trapped particle that is coupled to fluctuating fields in the vicinity of a room-temperature metallic and/or dielectric surface. Our results indicate a clear predominance of near field effects over ordinary blackbody radiation. We develop a theoretical framework for both charged and neutral particles with and witho

Benoit Gremaud, Dominique Delande

The harmonic inversion method is applied in the case of the hydrogen atom in a magnetic field to extract classical information from the quantum photo-ionization cross-section. The study is made close to a saddle-node bifurcation for which the usual semi-classical formulas give diverging contributions. All quantities (actions, stabilities and Maslov indices)

J. H. Kühn, A. A. Penin

The dominant electroweak double logarithmic corrections to the process $e^+e^-\to f\bar f$ at high energy are found in all orders of perturbation theory. In contrast to results in simple Yang-Mills theories these corrections do not exponentiate.

A. Ts. Amatuni

Interaction of external monochromatic, linearly polorized plane EM-wave with nonlinear one-dimensional wake wave, generated by relativistic electron bunch moving in cold plasma, is considered. At definite conditions on parameters of plasma and bunch, nonlinear wake wave can have a pronounced spikes, where plasma electron density has its maximum value and pla

G. Bilalbegovic

The current miniaturization of electronic devices raises many questions about the properties of various materials at nanometre-scales. Recent molecular dynamics computer simulations have shown that small finite nanowires of gold exist as multishelled structures of lasting stability. These classical simulations are based on a well-tested embedded atom potenti

X. Zotos, F. Naef, P. Prelovsek

Recent developments in the analysis of finite temperature dissipationless transport in integrable quantum many body problems are presented. In particular, we will discuss: (i) the role played by the conservation laws in systems as the spin 1/2 Heisenberg chain and the one-dimensional Hubbard model, (ii) exact results obtained using the Bethe ansatz method on

G. H. Arakelyan

In the framework of Quark-Gluon-String Model (QGSM) we calculate the inclusive spectra of meson and baryons with open charm in hadron-hadron collisions, obtained by SELEX and BEATRICE collaborations, taking into account the decays of corresponding S-wave resonances.

Linda S. Geux, Arne Brataas, Gerrit E. W. Bauer

We discuss a simple, semiclassical scattering theory for spin-dependent transport in a many-terminal formulation, with special attention to the four terminal device of Johnson referred to as spin transistor

L. I. Podloubny, P. P. J. M. Schram, S. A. Trigger

Real dusty crystals are inhomogeneous due to the presence of external forces. We suggest approximations for calculations of different types of inhomogeneous DC (chain and DC with a few slabs) in the equilibrium state. The results are in a good agreement with experimental results and can be used as an effective diagnostic method for many dusty systems.

J. Gasser

After a short summary of my talk, I discuss $K_{l3}$ decays and elastic $\pi\pi$ scattering in the framework of chiral perturbation theory.

A. Omont, S. Ganesh, C. Alard, J. A. D. L. Blommaert

The ISOGAL project is a survey of the stellar populations, structure, and recent star formation history of the inner disk and bulge of the Galaxy. ISOGAL combines 15 and 7micron ISOCAM observations with DENIS IJKs data to determine the nature of a source and the interstellar extinction. In this paper we report an ISOGAL study of a small field in the inner Ga

V. Pravda

The results of paper [1] are generalized for vacuum type-III solutions with, in general, a non-vanishing cosmological constant Lambda. It is shown that all curvature invariants containing derivatives of the Weyl tensor vanish if a type-III spacetime admits a non-expanding and non-twisting null geodesic congruence. A non-vanishing curvature invariant containi

Charles Francis

This is one of a number of papers in which the metric for space-time is defined on the subatomic level by means of the interchange of photons, and constrained to be consistent with radar. It is shown that the discrete nature of particle interactions necessitates a small inherent delay in the radar method, and hence that the resulting geometry is non- Euclide

P. E. Hardee, A. Rosen

Three-dimensional magnetohydrodynamical simulations of strongly magnetized ``light'' conical jets have been performed. An investigation of the transition from sub-Alfv\'enic to super-Alfv\'enic flow has been made for nearly poloidal and for helical magnetic fields. The jets are stable to asymmetric modes of jet distortion provided they are sub-Alfv\'enic ove

M. B. Weissman

Counting outcomes is the obvious algorithm for generating probabilities in quantum mechanics without state-vector reduction (i.e. many-worlds). This procedure has usually been rejected because for purely linear dynamics it gives results in disagreement with experiment. Here it is shown that if non-linear decoherence effects (previously proposed by other auth

R. Ibanez, M. de Leon, J. C. Marrero, E. Padron

The notion of Leibniz algebroid is introduced, and it is shown that each Nambu-Poisson manifold has associated a canonical Leibniz algebroid. This fact permits to define the modular class of a Nambu-Poisson manifold as an appropiate cohomology class, extending the well-known modular class of Poisson manifolds.

Salman Habib, Carmen Molina-Paris, Emil Mottola

We present a general formulation of the time-dependent initial value problem for a quantum scalar field of arbitrary mass and curvature coupling in a FRW cosmological model. We introduce an adiabatic number basis which has the virtue that the divergent parts of the quantum expectation value of the energy-momentum tensor <T_ab> are isolated in the vacuum piec

Alexei Ashikhmin, Alexander Barg, Emanuel Knill, Simon Litsyn

I. This paper is devoted to the problem of error detection with quantum codes. In the first part we examine possible problem settings for quantum error detection. Our goal is to derive a functional that describes the probability of undetected error under natural physical assumptions concerning transmission with error detection over the depolarizing channel.

G. A. Vilkovisky

Solution is presented to the simplest problem about the vacuum backreaction on a pair creating source. The backreaction effect is nonanalytic in the coupling constant and restores completely the energy conservation law. The vacuum changes the kinematics of motion like relativity theory does and imposes a new upper bound on the velocity of the source.

K. Saito, S. Takesue, S. Miyashita

We study how energy transport in an integrable system is affected by the spectral densities of heat reservoirs. The model investigated here is the quantum harmonic chain whose both ends are in contact with two heat reservoirs at different temperatures. The master equation for the reduced density matrix is derived on the assumption that the reservoirs are com

P. W. Gorham, K. M. Liewer, C. J. Naudet

Using the NASA Goldstone 70m antenna DSS 14 both singly and in coincidence with the 34 m antenna DSS 13 (21.7 km to the southeast), we have acquired approximately 12 hrs of livetime in a search for predicted pulsed radio emission from extremely-high energy cascades induced by neutrinos or cosmic rays in the lunar regolith. In about 4 hrs of single antenna ob

J. A. Garcia-Barreto, F. Combes, B. Koribalski, J. Franco

We have mapped the emission from atomic hydrogen at 21 cm from the galaxy NGC 3783 with the Australia Telescope Compact Array. Our main results are: a) the HI morphology is irregular and perturbed, gathered in three blobs apparently unrelated to the optical morphology; b) the observed HI velocity distribution indicates a normal disk in differential rotation

P. E. Hardee, A. Rosen, P. A. Hughes, G. C. Duncan

The amplitude of jet distortions and accompanying pressure and velocity fluctuations resulting from Kelvin-Helmholtz instability of three dimensional relativistic jets are explored. The effect of instability on jets as they accelerate from sub- to super-Alfvénic speeds is explored and a relativistic stabilization mechanism for trans-Alfvénic jets is proposed

Daniel J. H. Chung, Katherine Freese

We consider the cosmology that results if our observable universe is a 3-brane in a higher dimensional universe. In particular, we focus on the case where our 3-brane is located at the $Z_2$ symmetry fixed plane of a $Z_2$ symmetric five-dimensional spacetime, as in the Ho\v{r}ava-Witten model compactified on a Calabi-Yau manifold. As our first result, we fi

Alexander N. Korotkov

We consider the continuous quantum measurement of a two-level system, for example, a single-Cooper-pair box measured by a single-electron transistor or a double-quantum dot measured by a quantum point contact. While the approach most commonly used describes the gradual decoherence of the system due to the measurement, we show that when taking into account th

Owen G. Jepps, Gary Ayton, Denis J. Evans

We show that arbitrary phase space vector fields can be used to generate phase functions whose ensemble averages give the thermodynamic temperature. We describe conditions for the validity of these functions in periodic boundary systems and the Molecular Dynamics (MD) ensemble, and test them with a short-ranged potential MD simulation.

Charles F. Prosser, Robert C. Kennicutt,, Fabio Bresolin, Abhijit Saha

We report on the detection of Cepheids and the first distance measurement to the spiral galaxy NGC 1326-A, a member of the Fornax cluster of galaxies. We have employed data obtained with the Wide Field and Planetary Camera 2 on board the Hubble Space Telescope. Over a 49 day interval, a total of twelve V-band (F555W) and eight I-band (F814W) epochs of observ