May 2000 arXiv papers — page 6

L. A. Kuzmichev

During the last few years deep underwater neutrino telescopes of a new generation with dimensions close to 100 m or more were taken into operation. For the correct track reconstruction and for the interpretation of light pulses from calibration lasers one has to use the group velocity for light signals. The difference between group velocity leads to an addit

Alan D. Rendall, Claes Uggla

The dynamics of the Einstein-Vlasov equations for a class of cosmological models with four Killing vectors is discussed in the case of massive particles. It is shown that in all models analysed the solutions with massive particles are asymptotic to solutions with massless particles at early times. It is also shown that in Bianchi types I and II the solutions

Abel Camacho

In this work the possibility of detecting the presence of a Yukawa term, as an additional contribution to the usual Newtonian gravitational potential, is introduced. The central idea is to analyze the effects at quantum level employing interference patterns (at this respect the present proposal resembles the Colella, Overhauser and Werner experiment), and de

John Ellis, N. E. Mavromatos, D. V. Nanopoulos

Classical superstring vacua have zero vacuum energy and are supersymmetric and Lorentz-invariant. We argue that all these properties may be destroyed when quantum aspects of the interactions between particles and non-perturbative vacuum fluctuations are considered. A toy calculation of string/D-brane interactions using a world-sheet approach indicates that q

Sadhan K. Adhikari, A. Gammal

We reinvestigate the Bose-Einstein condensation (BEC) thermodynamics of a weakly interacting dilute Bose gas under the action of a trap using a semiclassical two-fluid mean-field model in order to find the domain of applicability of the model. Such a model is expected to break down once the condition of diluteness and weak interaction is violated. We find th

Z. Racz

Using the XXZ model for the description of one-dimensional magnetic materials we show that an energy flux, j_E, produces a shift, dk (j_E)^0.5, in the characteristic wavenumber of the spin-spin correlations. We estimate dk for a realistic experimental setup and find that it is measurable in inelastic neutron scattering experiments.

Angela Foerster, Jon Links, Arlei Prestes Tonel

We present two new integrable spin ladder models which posses three general free parameters besides the rung coupling J. Wang's systems based on the SU(4) and SU(3/1) symmetries can be obtained as special cases. The models are exactly solvable by means of the Bethe ansatz method.

O. A. Vasilyev

We present study of finite-size scaling and universality of crossing probabilities for the $q$-state Potts model. Crossing probabilities of the Potts model are similar ones in percolation problem. We numerically investigated scaling of $π_{s}$ - the probability of a system to percolate only in one direction for two-dimensional site percolation, the Ising mod

I. Mihalek, H. A. Fertig

We present a Hartree-Fock study that incorporates the effects of Landau level mixing and screening due to filled levels into the computation of energies and states of quasiparticles in quantum Hall ferromagnets. We use it to construct a phase diagram for skyrmion stability as a function of magnetic field and Zeeman coupling strengths. We find that Landau lev

Sadhan K. Adhikari

We present a numerical study of the time-dependent and time-independent Gross-Pitaevskii (GP) equation in two space dimensions, which describes the Bose-Einstein condensate of trapped bosons at ultralow temperature with both attractive and repulsive interatomic interactions. Both time-dependent and time-independent GP equations are used to study the stationa

Lev N. Shchur, Oleg A. Vasilyev

We have calculated analytically the mean value and the variance of the number of bonds on the lattices of dimension $d$ for the given occupation of sites. We consider both kinds of site occupation: with the fixed concentration $n_s$ of occupied sites and with the probability $p$ for a site to be occupied. We found that the variance are smaller in the former

Z. Garncarek, R. Piasecki

A linear transformation f(S) of configurational entropy with length scale dependent coefficients as a measure of spatial inhomogeneity is considered. When a final pattern is formed with periodically repeated initial arrangement of point objects the value of the measure is conserved. This property allows for computation of the measure at every length scale. I

Gilson F. Lima, Alexandre S. Martinez, Osame Kinouchi

Deterministic walks over a random set of points in one and two dimensions (d=1,2) are considered. Points (``cities'') are randomly scattered in R^d following a uniform distribution. A walker (a ``tourist''), at each time step, goes to the nearest neighbor city that has not been visited in the past τsteps. Each initial city leads to a trajecto

F. Kh. Abdullaev, R. A. Kraenkel

We study the macroscopic quantum tunneling, self-trapping phenomena in two weakly coupled Bose-Einstein condensates with periodically time-varying atomic scattering length. The resonances in the oscillations of the atomic populations are investigated. We consider oscillations in the cases of macroscopic quantum tunneling and the self-trapping regimes. The ex

Benjamin P. Vollmayr-Lee, Erik Luijten

In their recent Letter [Phys. Rev. Lett. 83, 4233 (1999)], Salazar and Toral (ST) study numerically a finite Ising chain with non-integrable interactions decaying like 1/r^(d+sigma) where -d <= sigma <= 0 (like ST, we discuss general dimensionality d). In particular, they explore a presumed connection between non-integrable interactions and Tsallis&#39;s non

Lorenzo Giada, Matteo Marsili

We introduce a simple continuous model for nonequilibrium surface growth. The dynamics of the system is defined by the KPZ equation with a Morse-like potential representing a short range interaction between the surface and the substrate. The mean field solution displays a non trivial phase diagram with a first order transition between a growing and a bound s

Ricardo Mansilla

A new approach to the understanding of the complex behavior of financial markets index using tools from thermodynamics and statistical physics is developed. Physical complexity, a magnitude rooted in the Kolmogorov-Chaitin theory is applied to binary sequences built up from real time series of financial markets indices. The study is based on NASDAQ and Mexic

Alexey V. Pan, Pablo Esquinazi

We have investigated the influence of a driving force on the elastic coupling (Labusch parameter) of the field-cooled state of the flux line lattice (FLL) in 400 nm thick YBa$_2$Cu$_3$O$_7$ superconducting films. We found that the FLL of a field-cooled state without driving forces is not in an equilibrium state. Results obtained for magnetic fields applied a

H. Kempa, Y. Kopelevich, F. Mrowka, A. Setzer

A magnetic-field-driven transition from metallic- to semiconducting-type behavior in the basal-plane resistance takes place in highly oriented pyrolytic graphite at a field $H_c \sim 1~$kOe applied along the hexagonal c-axis. The analysis of the data reveals a striking similarity between this transition and that measured in thin-film superconductors and Si M

Michael R. Geller, David J. Thouless, Sung-Wu Rhee, W. F. Vinen

It has been known since the pioneering work of Onsager and Feynman that the statistical mechanics and dynamics of vortices play an essential role in the behavior of superfluids and superconductors. However, the theory of vortices in quantum fluids remains in a most unsatisfactory state, with many conflicting results in the literature. In this paper we review

V. T. Petrashov, I. A. Sosnin, C. Troadec, I. Cox

We observe large amplitude changes in the resistance of ferromagnetic (F) wires at the onset of superconductivity of adjacent superconductors (S). New sharp peaks of large amplitude are found in the magnetoresistance of the F-wires. We discuss a new mechanism for the long-range superconducting proximity effect in F/S nanostructures based on the analysis of t

Efrat Shimshoni

The critical resistivity measured along the quantum Hall liquid--insulator transition line indicates a pronounced peak at a critical filling factor close to 1, which marks the crossover from the high to low magnetic field regime in the phase diagram. The origin of this behavior is explained in the framework of classical transport in a puddle network model. T

G. Bastian, H. Takayanagi

We have fabricated a sub-micron-sized structure consisting of an InAs-based 2DEG, two narrow Nb leads and a gate, where the indirect ballistic transport between the non-oppositely superconducting contacts can be controlled by the voltage applied to the gate. This new kind of tuneable junction can be used for applications and allows several fundamental questi

Takao Watanabe, Takenori Fujii, Azusa Matsuda

We find in the Bi2Sr2CaCu2O8+d system that the characteristic temperatures T*_chi [below which the uniform susceptibilities chi_ab(T) (H perpendicular to c) and chi_c(T)(H parallel to c) decrease] and T*_rho_c (below which the out-of-plane resistivity rho_c(T) shows typical upturn) coincide for all doping levels. We attribute the T dependence of chi&#39;s an

Roland Faller, Florian Müller-Plathe, Andreas Heuer

The reorientation dynamics of local tangent vectors of chains in isotropic amorphous melts containing semiflexible model polymers was studied by molecular dynamics simulations. The reorientation is strongly influenced both by the local chain stiffness and by the overall chain length. It takes place by two different subsequent processes: A short-time non-expo

M. Shatner, L. Muchnik, M. Leshno, S. Solomon

In order to simulate the complex phenomena manifested in stock markets, we introduce a continuous asynchronous model in which millions of individual traders interact through a central orders matching mechanism, just as it happens in real stock markets. Each trader has a unique decision function, which allows him/ her to trade at any time, to react to externa

Subir Sachdev, Matthias Vojta

The two-dimensional d-wave superconducting state of the high temperature superconductors has a number of different elementary excitations: the spin-singlet Cooper pairs, the spin S=1/2 fermionic quasiparticles, and a bosonic S=1 resonant collective mode, phi_{alpha}, at the antiferromagnetic wavevector. Although the phi_{alpha} quanta are strongly coupled to

D. A. Leahy, H. Marshall, D. Scott

Observations of Hercules X-1 by the Extreme Ultraviolet Explorer (EUVE) covering low state and the early part of the Short High state are reported here. This is the first EUV observation of this part of the 35-day cycle of Her X-1. The low state portion of the EUV light curve (prior to the start of the Short High state) has similar properties as that followi

D. J. Sahnow, H. W. Moos, T. Ake, J. Andersen

Launch of the Far Ultraviolet Spectroscopic Explorer (FUSE) has been followed by an extensive period of calibration and characterization as part of the preparation for normal satellite operations. Major tasks carried out during this period include initial coalignment, focusing and characterization of the four instrument channels, and a preliminary measuremen

H. W. Moos

The Far Ultraviolet Spectroscopic Explorer satellite observes light in the far-ultraviolet spectral region, 905 - 1187 A with high spectral resolution. The instrument consists of four coaligned prime-focus telescopes and Rowland spectrographs with microchannel plate detectors. Two of the telescope channels use Al:LiF coatings for optimum reflectivity from ap

Letizia Stanghellini, Alvio Renzini

We explore the realm of post-Asymptotic Giant Branch (post-AGB) stars from a theoretical viewpoint, by constructing synthetic population of transition objects, proto-Planetary Nebulae, Planetary Nebulae Nuclei, and post-Planetary Nebulae objects. We use the Montecarlo procedure to filter out the populations accordingly to a given set of assumptions. We explo

M. Tafalla, P. C. Myers, D. Mardones, R. Bachiller

We present molecular-line observations toward the dense core in L483 and its bipolar outflow powered by the Class 0 object IRAS 18148-0440. CO (carbon monoxide) maps show that the outflow is well collimated and asymmetric, and that its gas is warmer than the surrounding cloud by at least a factor of 2. H2CO (formaldehyde) lines toward the outflow show promin

L. Pentericci, W. Van Reeven, C. L. Carilli, H. J. A. Rottgering

We present new deep multi-frequency radio-polarimetric images of a sample of high redshift radio galaxies (HzRGs), having redshift between 1.7 and 4.1. The radio data at 4.7 and 8.2 GHz were taken with the Very Large Array in the A configuration and provide a highest angular resolution of 0.2&#39;&#39;. Maps of total intensity, radio spectral index, radio po

Julien Malzac, Elisabeth Jourdain

Using a non-linear Monte-Carlo code we investigate the radiative response of an accretion disk corona system to static homogeneous flares. We model a flare by a rapid (comparable to the light crossing time) energy dissipation in the corona or the disk. If the flares originate from the disk, the coronal response to the soft photon shots produces a strongly no

L. Testi, A. I. Sargent, L. Olmi, J. S. Onello

We present high resolution interferometric and single dish observations of molecular gas in the Serpens cluster-forming core. Star formation does not appear to be homogeneous throughout the core, but is localised in spatially- and kinematically-separated sub-clusters. The stellar (or proto-stellar) density in each of the sub-clusters is much higher than the

David S. Graff

I discuss two hypotheses that might explain LMC microlensing: the Halo stellar remnant lensing hypothesis and the unvirialized LMC lensing hypothesis. I show that white dwarfs cannot contribute substantially to the cosmic baryon budget; they are strongly constrained by chemical evolution and background light measurements. Although there have been some claims

J. Christopher Howk, Kenneth R. Sembach, Blair D. Savage

We use new Space Telescope Imaging Spectrograph (STIS) and archival Goddard High Resolution Spectrograph (GHRS) observations to study interstellar B II 1362 and O I 1355 absorption along seven sightlines. Our new column density measurements, combined with measurements of four sightlines from the literature, allow us to study the relative B/O abundances over

L. C. Garcia de Andrade

The evolution equation of linear cosmic density perturbations in the realm of Einstein-Cartan theory of gravity is obtained.The de Sitter metric fluctuation is computed in terms of the spin-torsion background density.

J. M. Paredes, J. Marti, M. Peracaula, G. Pooley

We report millimetre-wave continuum observations of the X-ray binaries Cygnus X-3, SS 433, LSI+61 303, Cygnus X-1 and GRS 1915+105. The observations were carried out with the IRAM 30 m-antenna at 250 GHz (1.25 mm) from 1998 March 14 to March 20. These millimetre measurements are complemented with centimetre observations from the Ryle Telescope, at 15 GHz (2.

T. Di Matteo, C. L. Carilli, A. C. Fabian

The radio emission from supermassive black holes in nearby early-type galaxies can be used to test possible explanations for their low luminosities. We calculate the expected contribution from thermal synchrotron emission from hot accretion flows to the high radio frequency observations of NGC 2300, NGC 1399, NGC 4278 and NGC 4594. We find that, in all cases

Roland Lehoucq, Jean-Philippe Uzan, Jean-Pierre Luminet

We investigate to what extent the cosmic crystallographic methods aimed to detect the topology of the universe using catalogues of cosmic objects would be damaged by various observational uncertainties. We find that the topological signature is robust in the case of Euclidean spaces, but is very fragile in the case of compact hyperbolic spaces. Comparing our

A. C. Davis, T. W. B. Kibble, M. Pickles, D. A. Steer

Chiral cosmic strings are produced naturally at the end of inflation in supersymmetric models where the symmetry is broken via a D-term. Consequently in such theories, where both inflation and cosmic strings contribute to the density and CMBR (microwave background) perturbations, it is necessary to understand the evolution of chiral cosmic string networks. W

V. Costa, M. Rayet, R. A. Zappalà, M. Arnould

The most detailed calculations of the p-process call for its development in the O/Ne layers of Type II supernovae. In spite of their overall success in reproducing the solar system content of p-nuclides, they suggest a significant underproduction of the light Mo and Ru isotopes. On grounds of a model for the explosion of a 25 solar mass star with solar metal

E. Carretti, A. Messina

Although poor for small dynamic scales, the Particle-Mesh (PM) model allows in astrophysics good insight for large dynamic scales at low computational cost. Furthermore, it is possible to employ a very high number of particles to get high mass resolution. These properties could be exploited by suitable parallelization of the algorithm. In PM there are two ty

Shinji Sato, Fumie Akimoto, Akihiro Furuzawa, Yasuki Kumai

We have determined the mass profiles of dark halos in 83 objects observed by ASCA. The point spread function of X-ray telescope was deconvoled by the Richardson-Lucy algorithm and the temperature profiles were calculated to obtain the mass profiles. The derived mass profiles are consistent with the NFW model in 0.01-1.0 r_virial. We found a good correlation

M. Juvela, K. Mattila, D. Lemke

As a part of the ISOPHOT CIRB (Cosmic Infrared Background Radiation) project we have searched for point-like sources in eight fields mapped at two or three wavelengths between 90 and 180um. Most sources are previously unknown and based on the far-infrared (FIR) spectral energy distributions dust-enshrouded, distant galaxies form a significant fraction of the

Jozef Klacka

Criteria for the membership of individual meteors in meteor streams are discussed from the point of view of their mathematical and also physical properties. Discussion is also devoted to the motivation. It is shown that standardly used criteria (mainly D-criterion of Southworth and Hawkins, 1963) have unusual mathematical properties in the sense of a term ``

Aldo Treves, Roberto Turolla, S. B. Popov

In some models of $γ$-ray bursts super-strong electric fields ($E\sim 10^{14} {\rm statvolt cm}^{-1}$) have been surmized. Such large fields may provide copious pair production through vacuum polarization. Here we examine various astrophysical scenarios where huge electric field can be present. It is shown that when the conditions for quantistic vacuum break

G. Contardo, B. Leibundgut, W. D. Vacca

We present empirical fits to the UBVRI light curves of type Ia supernovae. These fits are used to objectively evaluate light curve parameters. We find that the relative times of maximum light in the filter passbands are very similar for most objects. Surprisingly the maximum at longer wavelengths is reached earlier than in the B and V light curves. This clea

S. J. O&#39;Toole, T. R. Bedding, H. Kjeldsen, T. C. Teixeira

We report the detection of velocity variations in the pulsating sdB star, PG 1605+072. Oscillations are detected at the same frequencies found from photometry and have amplitudes of up to 14 km/s for H$β$. The strongest oscillation found in previous photometric observations is not evident in our spectroscopy or photometry, and may be absent due to beating of

Jean Swank

Recent measurements of young accreting binary neutron stars are determining more precise magnetic field and accretion parameters. A low magnetic field accreting, millisecond pulsar has finally been found in a binary burster. At least 20 low-mass binaries have exhibited high frequency oscillations, 300--1200 Hertz. The majority have, for some range of luminos

Anatoly Klypin

Properties of dark matter halos are reviewed. Taken from different publications, we present results on (1) the mass and velocity functions, (2) density and velocity profiles, and (3) concentration of halos. In the range of radii r=(0.005-1)rvir the density profile for a quiet isolated halo is very accurately approximated by a fit suggested by Moore etal (199

Anatoly Klypin

We give a summary of recent results on spatial and velocity biases in cosmological models. Progress in numerical techniques made it possible to simulate halos in large volumes with a such accuracy that halos survive in dense environments of groups and clusters of galaxies. Halos in simulations look like real galaxies, and, thus, can be used to study the bias

Anatoly Klypin

This lecture gives a short introduction to different methods used in cosmology. The focus is on major features of N-body simulations: equations, main numerical techniques, effects of resolution, and methods of halo identification.

Philip D. Mannheim

In this paper we explore some general aspects of the embeddings associated with brane-localized gravity. In particular we show that the consistency of such embeddings can require (or impose) very specific relations between all the involved bulk and brane matter source parameters. We specifically explore the embeddings of 3-branes with non-zero spatial 3-curv

M. S. Berger, Kim Siyeon

We show how introducing discrete Abelian flavor symmetries can produce texture zeros in the fermion mass matrices, while preserving the correct relationships with the low-energy data on quark and lepton masses. We outline a procedure for defining texture zeros as suppressed entries in Yukawa matrices. These texture zeros can account for the coexistence of th

C. Ford, J. M. Pawlowski, T. Tok, A. Wipf

We apply the ADHM instanton construction to SU(2) gauge theory on T^n x R^(4-n)for n=1,2,3,4. To do this we regard instantons on T^n x R^(4-n) as periodic (modulo gauge transformations) instantons on R^4. Since the R^4 topological charge of such instantons is infinite the ADHM algebra takes place on an infinite dimensional linear space. The ADHM matrix M is

Li-Xin Li

In this paper we present a model for making clean energy with a Kerr black hole. Consider a Kerr black hole with a dense plasma torus spinning around it. A toroidal electric current flows on the surface of the torus, which generates a poloidal magnetic field outside the torus. On the surface of the tours the magnetic field is parallel to the surface. The clo

S. N. Evangelou, Shi-Jie Xiong, P. Markov, D. E. Katsanos

The Anderson delocalization-localization transition is studied in multilayered systems with randomly placed interlayer bonds of density $p$ and strength $t$. In the absence of diagonal disorder (W=0), following an appropriate perturbation expansion, we estimate the mean free paths in the main directions and verify by scaling of the conductance that the state

J. M. Cordes, T. Joseph W. Lazio

This paper considers scattering screens that have arbitrary spatial variations of scattering strength transverse to the line of sight, including screens that are spatially well confined, such as disks and filaments. We calculate the scattered image of a point source and the observed pulse shape of a scattered impulse. The consequences of screen confinement i

Bachir Moussallam

Previous work relating the flavour variation of the chiral order parameters $F_π$, $<\bar u u>$ and S-wave scattering data, based on chiral sum rules and chiral perturbation theory at order $p^4$, is extended to include $O(p^6)$ corrections. The finding of a significant decrease of these order parameters, particularly $<\bar u u>$, with the number of flavour

Paul Mansfield, David Nolland

We test the Maldacena conjecture for type IIB String Theory/ N=4 Yang-Mills by calculating the one-loop corrections in the bulk theory to the Weyl anomaly of the boundary CFT when the latter is coupled to a Ricci-flat metric. The contributions cancel within each supermultiplet, in agreement with the conjecture.

Jurgen Schaffner-Bielich, Matthias Hanauske, Horst Stocker, Walter Greiner

Recent progress in the understanding of the high density phase of neutron stars advances the view that a substantial fraction of the matter consists of hyperons. The possible impacts of a highly attractive interaction between hyperons on the properties of compact stars are investigated. We find that a hadronic equation of state with hyperons allows for a fir

A. S. Alexandrov, V. V. Kabanov

Applying the canonical transformation with the 1/λperturbation expansion in the nonadiabatic and intermediate regime and the discrete generalisation of Pekar&#39;s continuous nonlinear equation in the extreme adiabatic regime we show that there are no strings in narrow-band ionic insulators due to the Frohlich electron-phonon interaction alone. The multi-pol

J. Wilms, M. A. Nowak, K. Pottschmidt, W. A. Heindl

We present the analysis of an RXTE monitoring campaign of the canonical soft state black hole candidates LMC X-1 and LMC X-3. In contrast to LMC X-1, which does not exhibit any periodic spectral changes, we find that LMC X-3 exhibits stron spectral variability on time scales of days to weeks. For typical RXTE ASM count rates, the luminosity variations of LMC

Flavio S. Nogueira

The anomalous scaling in the Ginzburg-Landau model for the superconducting phase transition is studied. It is argued that the negative sign of the $η$ exponent is a consequence of a special singular behavior in momentum space. The negative sign of $η$ comes from the divergence of the critical correlation function at finite distances. This behavior implies th

M. A. Nowak, J. Wilms, W. A. Heindl, K. Pottschmidt

We present results from 170ksec long RXTE observations of LMC X-1 and LMC X-3, taken in 1996 December, where their spectra can be described by a disc black body plus an additional soft (Gamma~2.8) high-energy power-law (detected up to 50keV in LMC X-3). These observations, as well as archival ASCA observations, constrain any narrow Fe line present in the spe

D. R. Bowler, A. J. Fisher

From electronic structure calculations, we find that carriers injected into dangling-bond atomic wires on the Si(001) surface will self-trap to form localised polaron states. The self-trapping distortion takes the form of a local suppression of the buckling of the dimers in the wire, and is qualitatively different for the electron and hole polarons. This res

J. Eisert, K. Jacobs, P. Papadopoulos, M. B. Plenio

We investigate the minimal resources that are required in the local implementation of non-local quantum gates in a distributed quantum computer. Both classical communication requirements and entanglement consumption are investigated. We present general statements on the minimal resource requirements and present optimal procedures for a number of important ga

Valery Gusynin, Anthony Hams, Manuel Reenders

A non-linear Schwinger-Dyson (SD) equation for the gauge boson propagator of massless QED in one time and two spatial dimensions is studied. It is shown that the nonperturbative solution leads to a nontrivial renormalization-group infrared fixed point quantitatively close to the one found in the leading order of the 1/N expansion, with N the number of fermio

Ali H. Chamseddine

The presence of a constant background antisymmetric tensor for open strings or D-branes forces the space-time coordinates to be noncommutative. This effect is equivalent to replacing ordinary products in the effective theory by the deformed star product. An immediate consequence of this is that all fields get complexified. The only possible noncommutative Ya

A. A. Sen, Indrajit Chakrabarty, T. R. Seshadri

We have investigated cosmological models with a self-interacting scalar field and a dissipative matter fluid as the sources of matter. Different variables are expressed in terms of a {\it generating function}. Exact solutions are obtained for one particular choice of the {\it generating function} The potential corresponding to this generating function is a s

Niels Asger Mortensen, Georg Bastian

We study the normal state conductance and the Josephson current in a superconductor-2DEG-superconductor structure where the size/shape of the 2DEG-region can be modified by an additional side-gate electrode. The considered transport properties follow from the retarded Green function which we compute by employing a tight-binding-like representation of the Ham

Lyudmila Turowska

Bounded Hilbert space *-representations are studied for a q-analogue of the *-algebra Pol(Mat_{2,2}) of polynomials on the space Mat_{2,2} of complex 2\times 2 matrices.

H. Takahashi, A. Ogura

We study an ambiguity of the current regularization in the Thirring model. We find a new current definition which enables to make a comprehensive treatment of the current. Our formulation is simpler than Klaiber&#39;s formulation. We compare our result with other formulations and find a very good agreement with their result. We also obtain the Schwinger term

Zurab Kakushadze

We consider localization of gravity in domain wall solutions of Einstein&#39;s gravity coupled to a scalar field with a generic potential. We discuss conditions on the scalar potential such that domain wall solutions are non-singular. Such solutions even exist for appropriate potentials which have no minima at all and are unbounded below. Domain walls of thi

Jiliang Jing, Mu-Lin Yan

With Carlip&#39;s boundary conditions, a standard Virasoro subalgebra with corresponding central charge for stationary dilaton black hole obtained in the low-energy effective field theory describing string is constructed at a Killing horizon. The statistical entropy of stationary dilaton black hole yielded by standard Cardy formula agree with its Bekenstein-

A. Honecker, A. Läuchli

Recent magnetization and susceptibility measurements on Cu3Cl6(H2O)2 2H8C4SO2 by Ishii et.al. [J. Phys. Soc. Jpn. 69, 340 (2000)] have demonstrated the existence of a spin gap. In order to explain the opening of a spin gap in this copper-trimer system, Ishii et.al. have proposed a frustrated trimer chain model. Since the exchange constants for this model hav

A. Yu. Ignatiev, R. R. Volkas

The Mirror Matter or Exact Parity Model sees every standard particle, including the physical neutral Higgs boson, paired with a parity partner. The unbroken parity symmetry forces the mass eigenstate Higgs bosons to be maximal mixtures of the ordinary and mirror Higgs bosons. Each of these mass eigenstates will therefore decay 50% of the time into invisible

D. Chruscinski

We study the strong field limit of p-form Born-Infeld theory. It turns out that this limiting theory is a unique theory displaying the full symmetry group of the underlying canonical structure. Moreover, being a nonlinear theory, it possesses an infinite hierarchy of conservation laws.

L. R. U. Manssur, A. L. M. A. Nogueira, M. A. Santos

The Symplectic Projector Method is applied to discuss quantisation aspects of an extended Abelian model with a pair of gauge potentials coupled by means of a mixed Chern-Simons term. We focuss on a field content that spans an N=2-D=3 supersymmetric theory whenever scalar and fermionic matter is suitably coupled to the family of gauge potentials.

P. V. Bogdanov, A. Lanzara, X. J. Zhou, S. A. Kellar

High resolution angle resolved photoemission data from Pb doped Bi_2Sr_2CaCu_2O_8 (Bi2212) with suppressed superstructure is presented. Improved resolution and very high momentum space sampling at various photon energies reveal the presence of two Fermi surface pieces. One has the hole-like topology, while the other one has its van Hove singularity very clos

Lay Nam Chang, Oleg Lebedev, Will Loinaz, Tatsu Takeuchi

We consider the Kaluza-Klein (KK) scenario in which only gravity exists in the bulk. Without the assumption of symmetric connection, the presence of brane fermions induces torsion. The result is a universal axial contact interaction that dominates those induced by KK gravitons. This enhancement arises from a large spin density on the brane. Using a global fi

Paolo Catelan, Marc Kamionkowski, Roger D. Blandford

We show with analytic models that the assumption of uncorrelated intrinsic ellipticities of target sources that is usually made in searches for weak gravitational lensing due to large-scale mass inhomogeneities (``field lensing'') is unwarranted. If the orientation of the galaxy image is determined either by the angular momentum or the shape of the halo in w

C. S. Unnikrishnan

The Einstein-Podolsky-Rosen nonlocality puzzle has been recognized as one of the most important unresolved issues in the foundational aspects of quantum mechanics. We show that the problem is resolved if the quantum correlations are calculated directly from local quantities which preserve the phase information in the quantum system. We assume strict locality

Daniel Collins, Noah Linden, Sandu Popescu

We show that quantum operations on multi-particle systems have a non-local content; this mirrors the non-local content of quantum states. We introduce a general framework for discussing the non-local content of quantum operations, and give a number of examples. Quantitative relations between quantum actions and the entanglement and classical communication re

Michael Bachmann, Hagen Kleinert, Axel Pelster

By an extension of the Feynman-Kleinert variational approach, we calculate the temperature-dependent effective classical potential governing the quantum statistical properties of a hydrogen atom in a uniform magnetic field. In the zero-temperature limit, we obtain ground state energies which are accurate for all magnetic field strengths from weak to strong f

Mario Castagnino, Roberto Laura

For a wide set of quantum systems it is demonstrated that the quantum regime can be considered as the transient phase while the final classical statistical regime is a permanent state. A basis where exact matrix decoherence appears for these final states is found. The relation with the decoherence of histories formalism is studied. A set of final intrinsical

Mario Castagnino, Roberto Laura

Using a functional method it is demonstrated that a generic quantum system evolves to a decohered state in a final pointer basis.

M. Lewenstein, J. I. Cirac, L. Santos

A system of bosons in a harmonic trap is cooled via their interactions with a thermal reservoir. We derive the master equation that governs the evolution of the system and may describe diverse physical situations: laser cooling, symphatetic cooling, etc. We investigate in detail the dynamics of the gas in the Lamb-Dicke limit, whereby the size of the trap is

Len M. Pismen, Yves Pomeau

The hydrodynamic phase field model is applied to the problem of film spreading on a solid surface. The disjoining potential, responsible for modification of the fluid properties near a three-phase contact line, is computed from the solvability conditions of the density field equation with appropriate boundary conditions imposed on the solid support. The equa

Len M. Pismen, Boris Y. Rubinstein

The profiles of a spreading wetting film are computed taking into account intermolecular forces and introducing a kinetic slip condition at a molecular cut-off distance. This eliminates the stress singularity, so that both &#34;true&#34; and &#34;visible&#34; contact angles are defined unequivocally. The &#34;true&#34; contact angle at the cut-off distance d

Victor M. Urbina

The trajectories of light are demostrated with experiments made with a microwave oscilator coupled to a horn antenna and a movable metalic plate along the radar beam. Two polarizations were made: Linear polarization that produced double cycloids paths and circular polarization that produced helical paths. Both trajectories filled the empty space around the t

C. D. Roberts, S. M. Schmidt

Continuum strong QCD is the application of models and continuum quantum field theory to the study of phenomena in hadronic physics, which includes; e.g., the spectrum of QCD bound states and their interactions; and the transition to, and properties of, a quark gluon plasma. We provide a contemporary perspective, couched primarily in terms of the Dyson-Schwin

H. W. Barz, B. Kampfer

The amplitude of subthreshold phi-meson production is calculated using dominant tree-level diagrams for three-body collisions. It is shown that the production can overwhelmingly be described by two-step processes. The effect of the genuine three-body contribution (i.e. the contribution which cannot be factorized) is discussed. The production rate of phi-meso

F. Hayot, C. Jayaprakash

We present results for the 1 dimensional stochastically forced Burgers equation when the spatial range of the forcing varies. As the range of forcing moves from small scales to large scales, the system goes from a chaotic, structureless state to a structured state dominated by shocks. This transition takes place through an intermediate region where the syste

L. M. Pismen

The boundary integral method is extended to derive closed integro-differential equations applicable to computation of the shape and propagation speed of a steadily moving spot and to the analysis of dynamic instabilities in the sharp boundary limit. Expansion of the boundary integral near the locus of traveling instability in a standard reaction-diffusion mo

Michael Lacey

The paper has been withdrawn by the author.

Jih-Hsin Cheng, I-Hsun Tsai

We study deformation of spherical $CR$ circle bundles over Riemann surfaces of genus > 1. There is a one to one correspondence between such deformation space and the so-called universal Picard variety. Our differential-geometric proof of the structure and dimension of the unramified universal Picard variety has its own interest, and our theory has its counte

Jih-Hsin Cheng

We establish Bochner-type formulas for operators related to $CR$ automorphisms and spherical $CR$ structures. From such formulas, we draw conclusions about rigidity by making assumptions on the Tanaka-Webster curvature and torsion.