May 1999 arXiv papers — page 6

I. Aretxaga, S. Benetti, R. J. Terlevich, A. C. Fabian

We present a spectro-photometric catalogue of the evolution of supernova 1988Z which combines new and published observations in the radio, optical and X-ray bands, with the aim of offering a comprehensive view of the evolution of this object and deriving the total energy radiated since discovery. The major contribution to the total radiated energy comes at o

A. Haungs, A. K. Razdan, C. L. Bhat, R. C. Rannot

Based on Monte Carlo simulations using the CORSIKA code, it is shown that Cerenkov images produced by ultrahigh energy $γ$-rays and cosmic ray nuclei (proton, Neon and Iron) are fractal in nature. The resulting multifractal and wavelet moments when employed in association with the conventional Hillas parameters as inputs to a properly-trained artificial neur

A. R. Patnaik, A. J. Kemball, R. W. Porcas, M. A. Garrett

We present polarisation observations of the gravitational lens system B1422+231 made at 8.4 GHz using the VLBA and the 100m telescope at Effelsberg. All four images of the quasar show structure on the milliarcsec scale. The three bright images show tangential stretching as expected from lens models. Some basic properties of gravitational lensing are exhibite

Rumen Bachev

The broad line profiles from a nonplanar (warped) accretion disk as a result from reprocessing of central hard radiation are studied in this paper. The disk is warped because of the Bardeen-Petterson effect. Obtained profiles depend significantly on the line of sight - they are asymmetric as well as frequency-shifted in most cases. Since such frequency shift

D. Martinez-Delgado, C. Gallart, A. Aparicio

We present new deep $VI$ ground-based photometry of the Local Group dwarf galaxy Phoenix. Our results confirm that this galaxy is mainly dominated by red stars, with some blue plume stars indicating recent (100 Myr old) star formation in the central part of the galaxy. We have performed an analysis of the structural parameters of Phoenix based on an ESO/SRC

Sara L. Ellison, Geraint F. Lewis, Max Pettini, Wallace L. W. Sargent

With an optical R-band magnitude of 15.2, the recently discovered z=3.911 BAL quasar APM 08279+5255 is an exceptionally bright high redshift source. Its brightness has allowed us to acquire a high signal-to-noise ratio (~100), high resolution (~6 km/s) spectrum using the HIRES echelle spectrograph on the 10-m Keck I telescope. Given the quality of the data,

Martin D. Weinberg

A combination of analytic models and n-body simulations implies that the structural evolution of the Large Magellanic Cloud (LMC) is dominated by its dynamical interaction with the Milky Way. Although expected at some level, the scope of the involvement has significant observational consequences. First, LMC disk orbits are torqued out of the disk plane, thic

Raphael Bousso

We conjecture the following entropy bound to be valid in all space-times admitted by Einstein's equation: Let A be the area of any two-dimensional surface. Let L be a hypersurface generated by surface-orthogonal null geodesics with non-positive expansion. Let S be the entropy on L. Then S does not exceed A/4. We present evidence that the bound can be saturat

S. J. van Enk

Teleportation of continuous variables can be described in two different ways, one in terms of Wigner functions, the other in terms of discrete basis states. The latter formulation provides the connection between the theory of teleportation of continuous degrees of freedom of a light field and the standard description of teleportation of discrete variables.

Ted Jacobson

A perturbative analysis shows that black holes do not remember the value of the scalar field $ϕ$ at the time they formed if $ϕ$ changes in tensor-scalar cosmology. Moreover, even when the black hole mass in the Einstein frame is approximately unaffected by the changing of $ϕ$, in the Jordan-Fierz frame the mass increases. This mass increase requires a reanal

M. A. Bransford, P. N. Appleton, C. F. McCain, K. C. Freeman

We present observations of the distribution and kinematics of neutral and ionized gas in NGC 1144, a galaxy that forms part of the Arp 118 system. Ionized gas is present over a huge spread in velocity (1100 km/s) in the disk of NGC 1144, but HI emission is detected over only 1/3 of this velocity range, in an area that corresponds to the NW half of the disk.

David A. Meyer

Only finite precision measurements are experimentally reasonable, and they cannot distinguish a dense subset from its closure. We show that the rational vectors, which are dense in S^2, can be colored so that the contradiction with hidden variable theories provided by Kochen-Specker constructions does not obtain. Thus, in contrast to violation of the Bell in

Todd A. Brun, James B. Hartle

The origin of classical predictability is investigated for the one dimensional harmonic chain considered as a closed quantum mechanical system. By comparing the properties of a family of coarse-grained descriptions of the chain, we conclude that local coarse-grainings in this family are more useful for prediction than nonlocal ones. A quantum mechanical syst

Claudio M. Maekawa, Carlos A. da Rocha

We present the contributions of the non-linear chiral scalar field S to cross sections of $pp\to dπ^{+}, pp\to pnπ^{+}$ and $pp\to ppπ^0$ reactions at threshold. We compare our results with the meson $σ$ contribution from the $σ$-linear model. We show that the chiral scalar field S is almost 5 times bigger than the other contributions, which indicates that t

Damien A. Easson, Robert H. Brandenberger

We consider the theory obtained by adding to the usual string frame dilaton gravity action specially constructed higher derivative terms motivated by the limited curvature construction of [MukhanovET1992a] and determine the spatially homogeneous and isotropic solutions to the resulting equations of motion. All solutions of the resulting theory of gravity wit

Johanna Erdmenger

We construct the three point function involving an axial vector current and two energy-momentum tensors for four dimensional conformal field theories. Conformal symmetry determines the form of this three point function uniquely up to a constant factor if the necessary conservation conditions are imposed. The gravitational axial anomaly present on a curved sp

G. E. Volovik, A. Vilenkin

We discuss parity violating effects in relativistic quantum theory and their analogues in effective field theory of superfluid 3He-A. A mixed axial-gravitational Chern-Simons term in the relativistic effective action and its condensed matter analog are responsible for the chiral fermion flux along the rotation axis of the heat bath in relativistic system and

Michael Gutperle

D-instanton effects are studied for the IIB orientifold T^2/IΩ(-1)^{F_L} of Sen using type I/heterotic duality. An exact one loop threshold calculation of t_8 \tr F^4 and t_8(\tr F^2)^2 terms for the heterotic string on T^2 with Wilson lines breaking SO(32) to SO(8)^4 is related to D-instanton induced terms in the worldvolume of D7 branes in the orientifold.

M. E. Carrington, W. F. Chen, G. Kunstatter, J. Mottershead

We investigate two-loop quantum corrections to non-minimally coupled Maxwell-Chern-Simons theory. The non-minimal gauge interaction represents the magnetic moment interaction between the charged scalar and the electromagnetic field. We show that the one-loop renormalizability of the theory found in previous work does not survive to the two-loop level. Howeve

J. A. Espichan Carrillo, A. Maia

We study the behavior of bound energy levels for the case of two classical interacting fields $ϕ$ and $χ$ in a finite domain (box) in (1 + 1) dimension on which we impose Dirichlet boundary conditions (DBC). The total Lagrangian contain a $\fracλ{4}ϕ^4$ self-interaction and an interaction term given by $g ϕ^2 χ^2$. We calculate the energy eigenfunctions and

Gregory Brown, Per Arne Rikvold, Mark Sutton, Martin Grant

Time-dependent properties of the speckled intensity patterns created by scattering coherent radiation from materials undergoing spinodal decomposition are investigated by numerical integration of the Cahn-Hilliard-Cook equation. For binary systems which obey a local conservation law, the characteristic domain size is known to grow in time $τ$ as $R = [B τ]^n

H. K. Jassal, A. Mukherjee, R. P. Saxena

The dynamics of a string near a Kaluza-Klein black hole are studied. Solutions to the classical string equations of motion are obtained using the world sheet velocity of light as an expansion parameter. The electrically and magnetically charged cases are considered separately. Solutions for string coordinates are obtained in terms of the world-sheet coordina

Chao-Shang Huang, Shou Hua Zhu

The differential branching ratio, forward-backward asymmetry, CP asymmetry and lepton polarization for a B-meson to decay to strange hadronic final states and a $τ^+τ^-$ pair in a CP softly broken two Higgs doublet model are computed. It is shown that contributions of neutral Higgs bosons to the decay are quite significant when $\tanβ$ is large. And it is pr

I. F. Ginzburg, G. L. Kotkin

The luminosity distribution in the effective $γγ$ mass at photon collider has usually two peaks which are well separated: high energy peak with mean energy spread 5-7% and wide low energy peak.The low energy peak depends strongly on details of design it is unsuitablefor the study of New Physics phenomena. We find simple approximte form of spectra of collided

Shinichi Deguchi, Bhabani Prasad Mandal

We apply a superspace formulation to the four-dimensional gauge theory of a massless Abelian antisymmetric tensor field of rank 2. The theory is formulated in a six-dimensional superspace using rank-2 tensor, vector and scalar superfields and their associated supersources. It is shown that BRS transformation rules of fields are realized as Euler-Lagrange equ

R. M. Crocker, R. Foot, R. R. Volkas

We examine the maximal $ν_e \to ν_s$ solution to the solar neutrino problem. This solution can be motivated by the exact parity model and other theories. The $ν_e$ survival probability exhibits one of three qualitatively different behaviours depending on the value of $Δm^2$, viz. approximately energy independent, just-so or MSW. By the last of these we mean

S. Bruce

Quantum mechanics asserts that a wave packet must inevitably spread as time progresses since the dispersion relation for the quantum waves is assumed to be quadratic in the momentum k. However, this assumption does not consider the standard frequency Doppler shift formula of Galilean relativity. In this article a non-dispersive wave packet is constructed by

A Calogeracos, N Dombey

The early papers by Klein, Sauter and Hund which investigate scattering off a high step potential in the context of the Dirac equation are discussed to derive the 'paradox' first obtained by Klein. The explanation of this effect in terms of electron-positron production is reassessed. It is shown that a potential well or barrier in the Dirac equation

S. Bruce, L. Roa

We determine the (bound) ground state of a spin 1/2 chargless particle with anomalous magnetic moment in certain Aharonov-Casher configurations. We recast the description of the system in a supersymmetric form. Then the basic physical requirements for unbroken supersymmetry are established. We comment on the possibility of neutron trapping in these systems.

S. Bruce et. al

We consider the problem of the bound states of a spin 1/2 chargless particle in a given Aharonov-Casher configuration. To this end we recast the description of the system in a supersymmetric form. Then the basic physical requirements for unbroken supersymmetry are established. We comment on the possibility of neutron confinement in this system.

Wen-Fa Lu

In the coordinate representation of thermofield dynamics, we investigate the thermalized displaced squeezed thermal state which involves two temperatures successively. We give the wavefunction and the matrix element of the density operator at any time, and accordingly calculate some quantities related to the position, momentum and particle number operator, s

M. I. Rabinovich, R. Huerta, A. Volkovskii, Henry D. I. Abarbanel

Studies of insect olfactory processing indicate that odors are represented by rich spatio-temporal patterns of neural activity. These patterns are very difficult to predict a priori, yet they are stimulus specific and reliable upon repeated stimulation with the same input. We formulate here a theoretical framework in which we can interpret these experimental

Russell Lyons, Oded Schramm

Let $Γ$ act on a countable set V with only finitely many orbits. Given a $Γ$-invariant random environment for a Markov chain on V and a random scenery, we exhibit, under certain conditions, an equivalent stationary measure for the environment and scenery from the viewpoint of the random walker. Such theorems have been very useful in investigations of percola

Viacheslav V. Nikulin

See Parts I and II in alg-geom/9711032 and alg-geom/9712033. Here we classify maximal hyperbolic root systems of the rank three having restricted arithmetic type and a generalized lattice Weyl vector $ρ$ with $ρ^2<0$ (i. e. of the hyperbolic type). We give classification of all reflective of hyperbolic type elementary hyperbolic lattices of the rank three. F

Jason Fulman

The eigenvalue spacing of a uniformly chosen random finite unipotent matrix in its permutation action on lines is studied. We obtain bounds for the mean number of eigenvalues lying in a fixed arc of the unit circle and offer an approach toward other asymptotics. For the case of all unipotent matrices, the proof gives a probabilistic interpretation to identit

Philippe Ellia

It is proved that a smooth rational surface in projective four-space, which is ruled by cubics or quartics has degree at most 12. It is also proved that a smooth rational surface in projective four-space which is the image of Fn by a linear system with &#34;simple base points&#34; (see text) has degree at most 12.

Krzysztof Ciesielski, Saharon Shelah

A function F:R^2->R is sup-measurable if F_f:R->R given by F_f(x)=F(x,f(x)), x in R, is measurable for each measurable function f:R->R. It is known that under different set theoretical assumptions, including CH, there are sup-measurable non-measurable functions, as well as their category analog. In this paper we will show that the existence of category analo

Igor Klebanov, Washington Taylor, Mark Van Raamsdonk

We calculate the leading term in the low-energy absorption cross section for an arbitrary partial wave of the dilaton field by a stack of many coincident D3-branes. We find that it precisely reproduces the semiclassical absorption cross section of a 3-brane geometry, including all numerical factors. The crucial ingredient in making the correspondence is the

Theodora Ioannidou, Paul M. Sutcliffe

For N>2 we present static monopole solutions of the second order SU(N) BPS Yang-Mills-Higgs equations which are not solutions of the first order Bogomolny equations. These spherically symmetric solutions may be interpreted as monopole anti-monopole configurations and their construction involves harmonic maps into complex projective spaces.

A. A. Akhmetshin, I. M. Krichever, Y. S. Volvovski

Discrete analogs of the Darboux-Egoroff metrics are considered. It is shown that the corresponding lattices in the Euclidean space are described by discrete analogs of the Lame equations. It is proved that up to a gauge transformation these equations are necessary and sufficient for discrete analogs of rotation coefficients to exist. Explicit examples of the

Toyohiro Tsurumaru, Izumi Tsutsui

Topological terms in the O(3) nonlinear sigma model in (1+1) and (2+1) dimensions are re-examined based on the description of the SU(2)-valued field $g$. We first show that the topological soliton term in (1+1) dimensions arises from the unitary representations of the group characterizing the global structure of the symmetry inherent in the description, in a

B. de Carlos, J. M. Moreno

We consider domain walls that appear in supersymmetric QCD with Nf < Nc massive flavours. In particular, for 2 Nf < Nc we explicitly construct the domain walls that interpolate between vacua labeled by i and (i+ N_f). We show that these solutions are Bogomol&#39;nyi-Prasad-Sommerfield (BPS) saturated for any value of the mass of the matter fields. This fact

Marco Bochicchio

We show that, as a consequence of a physical interpretation based on the Abelian projection and on the QCD string, four-dimensional QCD confines the electric flux if and only if the functional integral in the fiberwise-dual variables admits a hyper-Kahler reduction under the action of the gauge group.

Marco Bochicchio

We point out that the concept of Abelian projection gives us a physical interpretation of the role that the Hitchin fibration of parabolic K(D) pairs plays in the large-N limit of four-dimensional QCD. This physical interpretation furnishes also a simple criterium for the confinement of electric fluxes in the large-N limit of QCD. There is also an alternativ

Alexander Belyaev, Rogerio Rosenfeld, Alfonso R. Zerwekh

We perform a detailed study of the process of single color octet isoscalar $η_T$ production at the Tevatron with $η_T \to γ+ g$ decay signature, including a complete simulation of signal and background processes. We determined a set of optimal cuts from an analysis of the various kinematical distributions for the signal and backgrounds. As a result we show t

T. Asaka, M. Kawasaki

In superstring theories, there exist various dilaton and modulus fields which masses are expected to be of the order of the gravitino mass $m_{3/2}$. These fields lead to serious cosmological difficulties, so called ``cosmological moduli problem&#39;&#39;, because a large number of moduli particles are produced as the coherent oscillations after the primordi

S. L. Dubovsky, D. S. Gorbunov, S. V. Troitsky

Most phenomenologically acceptable supersymmetric models imply breaking of supersymmetry in a separate sector of fields introduced just for this purpose. Supersymmetry breaking is transferred to the Standard Model due to a certain interaction with this additional sector. In this review we disuss one of the popular mechanisms of such mediation with the key ro

K. S. Babu, B. Dutta, R. N. Mohapatra

We analyze CP violation in the supersymmetric standard model (MSSM) embedded minimally into a left-right symmetric gauge structure with the seesaw mechanism for neutrino masses. With the plausible assumption of universal scalar masses it is shown that CP violation in the hadron sector of the MSSM is described by a single phase residing in the supersymmetry b

P. I. Krastev

The data from all solar neutrino experiments presented at the Neutrino 98 conference has been analyzed and a brief summary of the status of the two most popular neutrino solutions of the solar neutrino problem, the MSW mechanism and vacuum oscillations, is presented here. The inclusion of the recoil-electron data and of the zenith angle distribution of event

Melissa A. Lampert, Benjamin Svetitsky

We study plasma oscillations in a flux tube of the dual superconductor model of &#39;t Hooft and Mandelstam. A magnetic condensate is coupled to an electromagnetic field by its dual vector potential, and fixed electric charges set up a flux tube. An electrically charged fluid (a quark plasma) flows in the tube and screens the fixed charges via plasma oscilla

Luis Gonzalez-Mestres

Present low-energy bounds on Lorentz symmetry violation do not allow to exclude the possible existence of superluminal particles (superbradyons) with critical speed in vacuum $c_i \gg c$ (c = speed of light) whose kinematical properties would be close to of &#34;ordinary&#34; particles (bradyons) apart from the difference in critical speed. If they exist, su

Luis Gonzalez-Mestres

Lorentz symmetry violation (LSV) is often discussed using models of the $THεμ$ type which involve, basically, energy independent parameters. However, if LSV is generated at the Planck scale or at some other fundamental length scale, it can naturally preserve Lorentz symmetry as a low-energy limit (deformed Lorentz symmetry, DLS). Deformed relativistic kinema

Srinath Cheluvaraja

We study a three-dimensional abelian lattice model in which the analogue of a theta term can be defined. This term is defined by introducing a neutral scalar field and its effect is to couple magnetic monopoles to the scalar field and vortices to the gauge field. An interesting feature of this model is the presence of an exact duality symmetry that acts on a

Rajiv V. Gavai, Manu Mathur

We investigate the effect of $Z_2$ magnetic monopoles and vortices on the finite temperature deconfinement phase transition in the fundamental - adjoint SU(2) lattice gauge theory. In the limit of complete suppression of the $Z_2$ monopoles, the mixed action for the SU(2) theory in its Villain form is shown to be self-dual under the exchange of the fundament

J. Breitweg

The cross section for dijet photoproduction at high transverse energies is presented as a function of the transverse energies and the pseudorapidities of the jets. The measurement is performed using a sample of ep-interactions corresponding to an integrated luminosity of 6.3 pb^(-1), recorded by the ZEUS detector.Jets are defined by applying a k_T-clustering

Soudan 2 Collaboration

The Soudan 2 deep underground tracking calorimeter has recorded cosmic ray muon tracks from the direction of the galactic x-ray binary Cygnus X-3 on most transits during the interval 1989-1998. We analyze these events in the context of previous reports of Cygnus X-3-related muon flux during major radio flares of that source. We find some evidence for excess

Soudan 2 Collaboration

A shadow of the moon, with a statistical significance of $5σ$, has been observed in the underground muon flux at a depth of 2090 mwe using the Soudan 2 detector. The angular resolution of the detector is well described by a Gaussian with $σ\le 0.3^{\circ}$. The position of the shadow confirms the alignment of the detector to better than $0.15^{\circ}$. This

Soudan 2 Collaboration

The absorption of cosmic rays by the sun produces a shadow at the earth. The angular offset and broadening of the shadow are determined by the magnitude and structure of the interplanetary magnetic field (IPMF) in the inner solar system. We report the first measurement of the solar cosmic ray shadow by detection of deep underground muon flux in observations

Luis Gonzalez-Mestres

Direct detection of WIMP dark matter candidates has to face many difficult challenges. In particular, it requires an extremely high level of background rejection. The only way out seems to be particle identification which, for experiments based on nucleus recoil, is most efficiently performed by simultaneously detecting ionization or light and phonons. When

Mark Trodden, Tanmay Vachaspati

The universe we observe is homogeneous on super-horizon scales, leading to the ``cosmic homogeneity problem&#39;&#39;. Inflation alleviates this problem but cannot solve it within the realm of conservative extrapolations of classical physics. A probabilistic solution of the problem is possible but is subject to interpretational difficulties. A genuine determ

D. L. Wiltshire

We derive exact series solutions for the Wheeler-DeWitt equation corresponding to a spatially closed Friedmann-Robertson-Walker universe with cosmological constant for arbitrary operator ordering of the scale factor of the universe. The resulting wave functions are those relevant to the approximation which has been widely used in two-dimensional minisuperspa

Sergiu I. Vacaru

Thermodynamic properties of locally anisotropic (2+1)-black holes are studied by applying geometric methods. We consider a new class of black holes with a constant in time elliptical event horizon which is imbedded in a generalized Finsler like spacetime geometry induced from Einstein gravity. The corresponding thermodymanic systems are three dimensional wit

Jose-Luis Rosales

We compute the regularized temperature for a spacetime foam model, consisting on S^4 instantons, in quantum gravity. Assuming that thermal equilibrium takes place with some amount of radiation - with thermal fields in the SU(2)xU(1) gauge theory - we obtain the remarkable result that the squared value of this temperature exactly coincides with the electrowea

Jose-Luis Rosales, Jose-Luis Sanchez-Gomez

It is proposed that the recently reported anomalous acceleration acting on the Pioneers spacecrafts should be a consequence of the existence of some local curvature in light geodesics when using the coordinate speed of light in an expanding spacetime. This suggests taht this &#34;Pioneer effect&#34; is nothing else but the detection of cosmological expansion

M. E. Simon, C. M. Varma

We solve the problem of a magnetic impurity in a $d_{x^2-y^2}$-wave superconductor by a variational method. A moment is found to exist in the superconducting state only if the Kondo-temperature in the normal state is larger than the maximum in the superconducting gap-function. If a moment exists in the superconducting state, and provided spin-orbit coupling

Boris A. Ivanov, Vladimir M. Muravyov, Denis D. Sheka

It is studied the scattering of magnons by the 2d topological Belavin-Polyakov soliton in isotropic ferromagnet. Analytical solutions of the scattering problem are constructed: (i) exactly for any magnon wave vectors for the partial wave with the azimuthal number m=1 (translational mode), and (ii) in the long- and short-wave limits for the rest modes. The ma

Yu. E. Lozovik, A. V. Poushnov

Stimulated two-photon emission by Bose-condensed excitons accompanied by a coherent two-exciton recombination, i.e., by simultaneous recombination of two excitons with opposite momenta leaving unchanged the occupation numbers of excitonic states with nonzero momenta, is investigated. Raman light scattering accompanied by a similar two-exciton recombination (

M. -H. Julien, Z. H. Jang, A. Lascialfari, F. Borsa

The proton nuclear spin-lattice relaxation rate 1/T1 has been measured as a function of temperature and magnetic field (up to 15 T) in the molecular magnetic ring Fe10. Striking enhancement of 1/T1 is observed around magnetic field values corresponding to a crossing between the ground state and the excited states of the molecule. We propose that this is due

Alok Shukla

In this paper we present a fully ab initio Hartree-Fock approach aimed at calculating the static structure factor of crystalline insulators at arbitrary values of momentum transfer. In particular, we outline the computation of the incoherent scattering function, the component of the structure factor which governs the incoherent x-ray scattering from solids.

Sergei A. Sergeenkov

The role of dipole-dipole interaction between Josephson diamagnetic moments is considered within a model system of two clusters (each cluster contains three weakly connected superconducting grains). The sign of the resulting critical current is shown to depend on the orientation between clusters, allowing for both 0 and $π$ type junctions behavior. The possi

Sergei A. Sergeenkov

A possible scenario for electric-field induced critical current enhancement in screw dislocated YBCO thin films is proposed based on the converse piezoelectric effect originated from a heavily defected medium of the superconducting films in an applied electric field. The magnitude of the effect is found to depend concurrently on the film thickness and the nu

C. Stampfl, M. Scheffler

In recent years due to improvements in calculation methods and increased computer power, it has become possible to perform first-principles investigations for ``simple&#39;&#39; chemical reactions at surfaces. We have carried out such studies for the catalytic oxidation of CO at transition metal surfaces, in particular, at the ruthenium surface for which unu

A. Sherman, M. Schreiber

A spin-wave theory of short-range order in the square lattice Heisenberg antiferromagnet is formulated. With growing temperature from T=0 a gapless mode is shown to arise simultaneously with opening a gap in the conventional spin-wave mode. The spectral intensity is redistributed from the latter mode to the former. For low temperatures the theory reproduces

Tin-Lun Ho, Sung Kit Yip

We show that the ground state of a spin-1 Bose gas with an antiferro- magnetic interaction is a fragmented condensate in uniform magnetic fields. The number fluctuations in each spin component change rapidly from being enormous (order $N$) to exceedingly small (order 1) as the magnetization of the system increases. A fragmented condensate can be turned into

B. Partoens, A. Matulis, F. M. Peeters

The electronic structure of two vertically coupled quantum dots containing two electrons is investigated in the presence of interdot tunneling. Our approach also includes the interdot exchange and we find that the tunneling is affected by the Coulomb interaction. There is an interplay between direct tunneling, the interdot exchange and the Coulomb interactio

Saar Rahav, Oded Agam, Shmuel Fishman

The eigenvalues of the Hyperspherical billiard are calculated in the semiclassical approximation. The eigenvalues where this approximation fails are identified and found to be related to caustics that approach the wall of the billiard. The fraction of energy levels for which the semiclassical error is larger than some given value is calculated analytically (

K. Z. Stanek, P. M. Garnavich, J. Kaluzny, W. Pych

We present $BVRI$ observations of the optical counterpart to the Gamma-Ray Burst (GRB) 990510 obtained with the Las Campanas 1.0-m telescope between 15 and 48 hours after the burst. The temporal analysis of the data indicates steepening decay, independent of wavelength, approaching asymptotically $t^{-0.76\pm 0.01}$ at early times ($t\ll 1 day)$ and $t^{-2.4

Nelson Caldwell

CCD images of three newly discovered dwarf spheroidal companions to M31, And V, VI, and VII, are used to extract surface brightness profiles and total magnitudes. Using distance modulii provided by Armandroff et al. (1998 & 1999) and Grebel & Guhathakurta (1999), these galaxies are shown to have similar luminosities to other Local Group dwarf spheroidals; An

J. S. Bloom, S. R. Kulkarni, S. G. Djorgovski, A. C. Eichelberger

Cosmic gamma-ray bursts (GRBs) have been firmly established as one of the most powerful phenomena in the Universe, releasing electromagnetic energy approaching the rest-mass energy of a neutron star in a few seconds. The two currently popular models for GRB progenitors are the coalescence of two compact objects (such as neutron stars or black holes) or colla

P. M. Ogle, M. H. Cohen, J. S. Miller, H. D. Tran

We present a spectropolarimetric survey of 36 broad absorption line quasi-stellar objects (BAL QSOs). The continuum, absorption trough, and emission line polarization of BAL QSOs yield clues about their structure. We confirm that BAL QSOs are in general more highly polarized than non-BAL QSOs, consistent with a more equatorial viewing direction for the forme

S. Y. Panitkin, W. J. Llope, R. Mattiello, B. Monreal

We present predictions for the formation of (anti)nuclear bound states in Au+Au central collisions at $\sqrt{s}=200A$ GeV. The coalescence afterburner was applied to the freeze-out phase space distributions of nucleons provided by the transport model, RQMD version 2.4. We study the sensitivity of the deuteron spectra to space-momentum correlations. It is fou

A. Ashtekar, A. Corichi, K. Krasnov

A Hamiltonian framework is introduced to encompass non-rotating (but possibly charged) black holes that are ``isolated&#39;&#39; near future time-like infinity or for a finite time interval. The underlying space-times need not admit a stationary Killing field even in a neighborhood of the horizon; rather, the physical assumption is that neither matter fields

Anatoliy K. Prykarpatsky

A symplectic theory approach is devised for solving the problem of algebraic-analytical construction of integral submanifold imbeddings for integrable (via the nonabelian Liouville-Arnold theorem) Hamiltonian systems on canonically symplectic phase spaces.

N. Brosch, E. Almoznino, B. Wszolek, K. Rudnicki

We detected a ring-like distribution of far-infrared emission in the direction of the center of the Virgo cluster. We studied this feature in the FIR, radio, and optical domains, and deduced that the dust within the feature reddens the galaxies in the direction of the Virgo cluster but does not affect stars within the Milky Way. This is likely to be a dusty

Victor G. Zubko, Ari Laor

Spectropolarimetry from the near IR to the far UV of light scattered by dust provides a valuable diagnostic of the dust composition, grain size distribution and spatial distribution. To facilitate the use of this diagnostic, we present detailed calculations of the intensity and polarization spectral signature of light scattered by optically thin and opticall

Giorgio Parisi

In this note I present a simplified version of the recent computation (Mezard and Parisi 1998, 1999) of the properties of glasses in the low temperature phase in the framework of the replica theory, using an extension of the tools used in liquid theory. I will only consider here the case of the internal energy at T=0, which can be studied in a simple way wit

S. Y. Panitkin

First measurements of the beam energy dependence of the two proton correlation function in central Au+Au collisions are performed by the E895 Collaboration at the BNL AGS. No significant changes with beam energy were observed. The imaging technique of Brown-Danielewicz is used in order to extract information about the space-time content of the proton source

Alexander Schmitt

Let $X$ be a complex projective manifold. Fix two ample line bundles $H_0$ and $H_1$ on $X$. It is the aim of this note to study the variation of the moduli spaces of Gieseker semistable sheaves for polarizations lying in the cone spanned by $H_0$ and $H_1$. We attempt a new definition of walls which naturally describes the behaviour of Gieseker semistabilit

E. Baver, D. Gepner, U. Gursoy

Pseudo conformal field theories are theories with the same fusion rules, but with different modular matrix as some conventional field theory. One of the authors defined these and conjectured that, for bosonic systems, they can all be realized by some actual RCFT, which is of free bosons. We complete the proof here by treating the non diagonal automorphism ca

Jishnu Dey, Siddhartha Bhowmik, Kanad Ray, Subharthi Ray

The experimental hadronic density of states dN/dm, assumed to be a sum of normalized Breit- Wigner distributions and plotted as a function of the hadron mass m, fails to show a Hagedorn like growth beyond 2 GeV, probably due to a lack of data. Experimental hadronic states are fitted using $\ka$ -deformed Poincaré algebra and the fit is used to extrapolate fo

Jishnu Dey, Mira Dey, P. Leal Ferreira, Lauro Tomio

The exciting feature of recent times is the inflow of new experimental data. Fits to the $π, \r$ and f meson resonances found by the VES collaboration, along with those of the PDG 1998 compilation are reported using a non-linear model for Regge trajectories. There are only five parameters including the pion mass and the states come out as Regge -type excitat

S. Jadach, B. F. L. Ward, Z. Was

We present the first-order coherent exclusive exponentiation (CEEX) scheme, with the full control over spin polarization for all fermions. In particular it is applicable to difficult case of narrow resonances. The resulting spin amplitudes and the differential distributions are given in a form ready for their implementation in the Monte Carlo event generator

E. -M. Ilgenfritz, S. Thurner

We summarize recent attempts to extract characteristics of non-perturbative vacuum structure from lattice measurements of the gauge invariant field strength correlator. As an alternative to cooling, we propose to apply the renormalization group (RG) smoothing method in lattice studies. For pure SU(2) gauge theory we present magnetic and electric correlation

Y. C. Huang, B. L. Lin, S. Li, M. X. Shao

General Weitzenbock material manifolds of dislocations in crystals Are proposed, the reference, idealized and deformation states of the bodies in general case are generally described by the general manifolds, the topological gauge field theory of dislocations is given in general case,true distributions and evolution of dislocations in crystals are given by t

Ismael Tereno

It is shown that a timelike radial geodesic does not become null at the event horizon

P. Traat

We discuss on the basis of our evolutionary spectral models the impact of chemical composition on the spectrum of stellar population formed in the starburst. Their metallicity range Z=0.0001 - 0.05(0.1) fully covers the observable one; depending on age, wavelength region and IMF the UV-fluxes differ between extreme compositions at least tenfold, usually more

Leonardo Testi, Marcello Felli, Gregory B. Taylor

We present VLA radio continuum observations at 3.6 and 6 cm of a ~0.65 sq.deg. field in the galactic plane at l=+45deg . These observations are meant to be used in a comparison with ISO observations at 7 and 15 um of the same region. In this paper we compare the radio results with other radio surveys and with the IRAS-PSC. At 3.6 and/or 6 cm we detect a tota

Krzysztof M. Gorski, Benjamin D. Wandelt, Frode K. Hansen, Eric Hivon

HEALPix is a Hierarchical, Equal Area, and iso-Latitude Pixelisation of the sphere designed to support efficiently - local operations on the pixel set, - a hierarchical tree structure for multi-resolution applications, and - the global Fast Spherical Harmonic transform. The HEALPix concept and the mathematical software based on it introduced in this primer m

Daniel Jonathan, Martin B. Plenio

We demonstrate that local transformations on a composite quantum system can be enhanced in the presence of certain entangled states. These extra states act much like catalysts in a chemical reaction: they allow otherwise impossible local transformations to be realised, without being consumed in any way. In particular, we show that this effect can considerabl

Marco Frasca

A perturbative study of the Schrödinger equation in a strong electromagnetic field with dipole approximation is accomplished in the Kramers-Henneberger frame. A prove that just odd harmonics appear in the spectrum for a linear polarized laser field is given, assuming that the atomic radius is much lesser than the free-electron quiver motion amplitude. Within