arXiv papers from February 1999

Gabriel H. Flores, Rudnei O. Ramos, N. F. Svaiter

We evaluate both the vacuum decay rate at zero temperature and the finite temperature nucleation rate for the $(\lambda\phi^4/4! + \sigma\phi^6/6!)_{3D}$ model. Using the thin-wall approximation, we obtain the bounce solution for the model and we were also able to give the approximate eigenvalue equations for the bounce.

G. Sereny

The fact that the famous Godel incompleteness theorem and the archetype of all logical paradoxes, that of the Liar, are related closely is, of course, not only well known, but is a part of the common knowledge of logician community. Actually, almost every more or less formal treatment of the theorem (including, for that matter, Godel's original paper as well

Tom Broadhurst, Rychard J. Bouwens

The optical-IR images of the Northern and Southern Hubble Deep Fields are used to measure the spectral and density evolution of early-type galaxies. The mean optical SED is found to evolve passively towards a mid F-star dominated spectrum by z ~ 2. We demonstrate with realistic simulations that hotter ellipticals would be readily visible if evolution progres

Tom Leinster

fc-multicategories are a very general kind of two-dimensional structure, encompassing bicategories, monoidal categories, double categories and ordinary multicategories. We define them and explain how they provide a natural setting for two familiar categorical ideas. The first is the bimodules construction, traditionally carried out on suitably cocomplete bic

Marco Mackaay

In this paper we define a class of state-sum invariants of compact closed oriented piece-wise linear 4-manifolds using finite groups. The definition of these state-sums follows from the general abstract construction of 4-manifold invariants using spherical 2-categories, as we defined in a previous paper, although it requires a slight generalization of that c

C. Correia da Silva, R. M. Williams

We generalize simplicial minisuperspace models associated with restricting the topology of the universe to be that of a cone over a closed connected combinatorial $3-$manifold by considering the presence of a massive scalar field. By restricting all the interior edge lengths and all the boundary edge lengths to be equivalent and the scalar field to be homoge

Stefano Foffa, Michele Maggiore, Riccardo Sturani

We examine the effect of perturbative string loops on the cosmological pre-big-bang evolution. We study loop corrections derived from heterotic string theory compactified on a $Z_N$ orbifold and we consider the effect of the all-order loop corrections to the Kahler potential and of the corrections to gravitational couplings, including both threshold correcti

M. Ladisa, G. Nardulli, P. Santorelli

In the framework of a QCD relativistic potential model we evaluate the form factors describing the exclusive decays B => \pi l nu and B => K l+ l-. The present calculation extends a previous analysis of B meson decays into light vector mesons. We find results in agreement with the data, when available, and with the theoretical constraints imposed by the Call

Paolo Di Vecchia

This is an introduction to the Maldacena conjecture on the equivalence between ${\cal{N}}=4$ super Yang-Mills in Minkowski space-time and type IIB string theory compactified on $AdS_5 \otimes S_5 $.

Abdelghani Zeghib

All the actions considered here are (real) analytic. Consider a subgroup of finite index of SL(n, Z). We prove, in particular, the (global) homotopical rigidity, for both its standard affine action on the torus of dimension n > 2, and its standard projective action on the sphere of dimesnion n-1>3.

P. E. Kornilovitch

A formula is derived that relates the ground-state dispersion of a many-body system with the end-to-end distribution of paths with open boundary conditions in imaginary time. The formula does not involve the energy estimator. It allows direct measurement of the ground-state dispersion by quantum Monte Carlo methods without analytical continuation or auxiliar

Uwe Grimm, Michael Schreiber

We briefly review the standard methods used to construct quasiperiodic tilings, such as the projection, the inflation, and the grid method. A number of sample Mathematica programs, implementing the different approaches for one- and two-dimensional examples, are discussed. Apart from small examples, the corresponding programs are not contained in the text, bu

M. J. E. Richardson, Y. Kafri

The effects of a boundary on reaction systems are examined in the framework of the general single-species reaction/coalescence process. The boundary naturally represents the reactants' container, but is applicable to exciton dynamics in a doped TMMC crystal. We show that a density excess, which extends into the system diffusively from the boundary, is formed

M. D. Albrow, J. -P. Beaulieu, J. A. R. Caldwell, D. L. DePoy

We present a method to analyze binary-lens microlensing light curves with one well-sampled fold caustic crossing. In general, the surface of chi^2 shows extremely complicated behavior over the 9-parameter space that characterizes binary lenses. This makes it difficult to systematically search the space and verify that a given local minimum is a global minimu

Eyal Neistein, Dan Maoz, Hans-Walter Rix, John L. Tonry

We present an I-band Tully-Fisher relation (TFR) for 18 nearby S0 galaxies using kinematics derived from long slit spectroscopy of stellar absorption lines. Our estimates of the circular velocity, V_c, at 2-3 exponential disk scale lengths account for line-of-sight projection and for the stellar random motions through an asymmetric drift correction. Uniform

S. Groot Nibbelink, J. W. van Holten

A consistent N=1 supersymmetric $\sigma$-model can be constructed, given a K\"ahler manifold by adding chiral matter multiplets. Their scalar components are covariant tensors on the underlying K\"ahler manifold. The K\"ahler U(1)-charges can be adjusted such that the anomalies cancel, using the holomorphic functions in which the K\"ahler potential transforms

Jacob D. Bekenstein, Avraham E. Mayo

Zaslavskii has suggested how to tighten Bekenstein's bound on entropy when the object is electrically charged. Recently Hod has provided a second tighter version of the bound applicable when the object is rotating. Here we derive Zaslavskii's optimized bound by considering the accretion of an ordinary charged object by a black hole. The force originating fro

Fabian H. L. Essler, Holger Frahm

We consider density-density correlations in the one-dimensional Hubbard model at half filling. On intuitive grounds one might expect them to exhibit an exponential decay. However, as has been noted recently, this is not obvious from the Bethe Ansatz/conformal field theory (BA/CFT) approach. We show that by supplementing the BA/CFT analysis with simple symmet

Y. -S. Dai, D. -S. Du, X. -Q. Li, Z. -T. Wei

It is believed that the production rate of $D^0\to K^0\bar K^0$ is almost solely determined by final state interactions (FSI) and hence provides an ideal place to test FSI models. Here we examine model calculations of the contributions from s-channel resonance $f_J(1710)$ and t-channel exchange to the FSI effects in $D^0\to K^0\bar K^0$. The contribution fro

Kohkichi Konno, Yasufumi Kojima

We discuss distortion in microlensing-induced light curves which are considered to be curves due to single-point-mass lenses at a first glance. As factors of the distortion, we consider close binary and planetary systems, which are the limiting cases of two-point-mass lenses, and the gravitational potential is regarded as the sum of the single point mass and

A. K. Mishra

An appropriate model Hamiltonian based formalism is proposed for a random adsorbate layer with arbitrary coverage and the ensuing two-dimensional band formation by metallic adsorbates in the monolayer regime. The coherent potential approximation is employed to handle the randomness. The adsorbate self-energy is evaluated explicitly using the density of state

Qing Wang, Yu-Ping Kuang, Xue-Lei Wang, Ming Xiao

We formally derive the chiral Lagrangian for low lying pseudoscalar mesons from the first principles of QCD considering the contributions from the normal part of the theory without taking approximations. The derivation is based on the standard generating functional of QCD in the path integral formalism. The gluon-field integration is formally carried out by

G. A. Tammann, A. Sandage

The absolute magnitude M* of the peak of the globular cluster luminosity function (GCLF), approximated by a Gaussian, can be calibrated independently in the Galaxy and M 31 through RR Lyr stars and Cepheids, respectively. They yield, in perfect agreement, M*_B = -6.93+-0.08 and M*_V = -7.62+-0.08. Application of these values to the GCLFs in the Leo Group (n=

Massimo Giovannini

A large class of quintessential inflationary models, recently proposed by Peebles and Vilenkin, leads to post-inflationary phases whose effective equation of state is stiffer than radiation. The expected gravitational waves logarithmic energy spectra are tilted towards high frequencies and characterized by two parameters: the inflationary curvature scale at

Reinoud J. Slagter

We investigated the stability of the spherically symmetric non-abelian (Bartnik-McKinnon) black hole solution of the SU(2) Einstein-Yang-Mills system using the multiple-scale analysis. It is found, in contrast with the vacuum situation, that a spherically symmetric oscillatory perturbation to second order cannot be constructed. The singular behavior of gravi

Edward Witten

In N=1 super Yang-Mills theory in three spacetime dimensions, with a simple gauge group $G$ and a Chern-Simons interaction of level $k$, the supersymmetric index $\Tr (-1)^F$ can be computed by making a relation to a pure Chern-Simons theory or microscopically by an explicit Born-Oppenheimer calculation on a two-torus. The result shows that supersymmetry is

O. M. Del Cima

We present some comments concerning the validity of the Nielsen identities for renormalizable theories quantized in general linear covariant gauges in a context of compact gauge Lie groups.

F. Wang

The two-proton correlation function at midrapidity from Pb+Pb central collisions at 158 AGeV has been measured by the NA49 experiment. The preliminary results are compared to model predictions from proton source distributions of static thermal Gaussian sources and the transport models of RQMD and VENUS. We obtain an effective proton source size 4.0 +-0.15(st

B. Noheda, D. E. Cox, G. Shirane, J. A. Gonzalo

A previously unreported ferroelectric phase has been revealed on a highly homogeneous sample of Pb(Zr0.52Ti0.48)O3 by high-resolution synchrotron x-ray powder diffraction measurements. At ambient temperature the sample has tetragonal symmetry (at= 4.037 A, ct= 4.138 A), and transforms below ~250 K into a phase which, unexpectedly, has monoclinic symmetry (am

M. -H. Julien, F. Borsa, P. Carretta, M. Horvatic

A 63Cu and 139La NMR/NQR study of superconducting (Tc=7 K) La1.94Sr0.06CuO4 single crystal is reported. Coexistence of spin-glass and superconducting phases is found below ~5 K from 139La NMR relaxation. 63Cu and 139La NMR spectra show that, upon cooling, CuO2 planes progressively separate into two magnetic phases, one of them having enhanced antiferromagnet

Edwin Lo, B. R. Judd

The symmetric group $S_6$ that permutes the six five-fold axes of an icosahedron is introduced to go beyond the simple rotations that constitute the icosahedral group $I$. Owing to the correspondence $h\leftrightarrow d$, the calculation of the Coulomb energies for the icosahedral configurations $h^N$ based on the sequence $O(5) \supset S_6 \supset S_5 \sups

J. Burki, C. A. Stafford, X. Zotos, D. Baeriswyl

The cohesion and conductance of a point contact in a two-dimensional metallic nanowire are investigated in an independent-electron model with hard-wall boundary conditions. All properties of the nanowire are related to the Green's function of the electronic scattering problem, which is solved exactly via a modified recursive Green's function algorithm. Our r

John Ellis

Arguments are given that the lightest supersymmetric particle should be a neutralino $\chi$. Minimizing the fine tuning of the gauge hierarchy favours $\Omega_{\chi} h^2 \sim 0.1$. There are important constraints on the parameter space of the MSSM from the stability of the electroweak vacuum. Co-annihilation with the next-to-lightest supersymmetric particle

E. O. Iltan

We study the differential Branching ratio and CP asymmetry for the exclusive decay B --> K^* l^+ l^- in the three Higgs doublet model with additional global O(2) symmetry in the Higgs sector. We analyse dilepton mass square q^2 dependency of the these quantities. Further, we study the effect of new parameter of the global symmetry in the Higgs sector on the

Jan Naudts, Frank Redig, Stefan Van Gulck

We study the relaxation properties of the voter model with i.i.d. random bias. We prove under mild condions that the disorder-averaged relaxation of this biased random voter model is faster than a stretched exponential with exponent $d/(d+\alpha)$, where $0<\alpha\le 2$ depends on the transition rates of the non-biased voter model. Under an additional assump

P. A. Horvathy, J. -C. Yera

The cubic non-linear Schr\"odinger equation where the coefficient of the nonlinear term is a function $F(t,x)$ only passes the Painlev\'e test of Weiss, Tabor, and Carnevale only for $F=(a+bt)^{-1}$, where $a$ and $b$ are constants. This is explained by transforming the time-dependent system into the constant-coefficient NLS by means of a time-dependent non-

Kostas Skenderis

We discuss the field theory limit of Dp-branes. In this limit, the black Dp-brane solution approaches a solution which is conformal to adS_{p+2} \times S^{8-p}. We argue that the frame in which the conformal factor is equal to one, the dual frame, is a `holographic' frame. The radial coordinate of adS_{p+2} provides a UV/IR connection as in the case of the D

George Chikenji, Macoto Kikuchi, Yukito Iba

Long chains of the HP lattice protein model are studied by the Multi-Self-Overlap Ensemble(MSOE) Monte Carlo method, which was developed recently by the authors. MSOE successfully finds the lowest energy states reported before for sequences of the chain length $N=42\sim 100$ in two and three dimensions. Moreover, MSOE realizes the lowest energy state that ev

Takashi Hamana, Hugo Martel, Toshifumi Futamase

We compute statistical properties of weak gravitational lensing by large-scale structure in three Cold Dark Matter models. We use a P$^3$M $N$-body code to simulate the formation and evolution of large-scale structure in the universe. We perform $1.1\times10^7$ ray-tracing experiments for each model using the multiple lens-plane algorithm. From the results o

Masashige Matsumoto, Manfred Sigrist

The chiral optical absorption by a single vortex in a p_x \pm i p_y-wave superconductor is studied theoretically. The p_x \pm i p_y-wave state was recently suggested as the symmetry of the order parameter of Sr_2 Ru O_4 superconductor. Due to the violation of time reversal symmetry, there are two types of vortices whose winding orientation is the same or opp

Denis V. Juriev

The note is devoted to an interactive game theoretic formalization of dialogues as psycholinguistic phenomena and the unraveling of a hidden dialogue structure of 2-person differential interactive games. In the field-theoretic description of interactive games the dialogues are defined naively as interactive games of discrete time with intention fields of con

Bidhan Chandra Bag, Deb Shankar Ray

A semiclassical theory of dissipative Henon-Heiles system is proposed. Based on $\hbar$-scaling of an equation for evolution of Wigner quasiprobability distribution function in presence of dissipation and thermal diffusion, we derive a semiclassical equation for quantum fluctuations, governed by the dissipation and the curvature of the classical potential. W

Tomoya Isoshima, Kazushige Machida

The instability condition of the non-vortex state toward vortex formation is exa mined within the Bogoliubov theory when a Bose-Einstein condensate is under exte rnally forced rotation. The obtained critical angular velocity combined with the previous stability cond itions for a votex yields a detailed phase diagram in the critical velocity vs t he system pa

Lucien Hardy

We consider the problem of how to manipulate the entanglement properties of a general two-particle pure state, shared between Alice and Bob, by using only local operations at each end and classical communication between Alice and Bob. A method is developed in which this type of problem is found to be equivalent to a problem involving the cutting and pasting

Alex Kamenev, Marc Mezard

We compute energy level correlations in weakly disordered metallic grains using the fermionic replica method. We use the standard sigma-model approach and show that non--trivial saddle points, which break replica symmetry, must be included in the calculation to reproduce the oscillatory behavior of the correlations. We calculate the correlation functions in

E. D'Hoker, D. H. Phong

We summarize recent results on the construction of Lax pairs with spectral parameter for the twisted and untwisted elliptic Calogero-Moser systems associated with arbitrary simple Lie algebras, their scaling limits to Toda systems, and their role in Seiberg-Witten theory. We extend part of this work by presenting a new parametrization for the spectral curves

J. Main, G. Wunner

A general technique for the periodic orbit quantization of systems with near-integrable to mixed regular-chaotic dynamics is introduced. A small set of periodic orbits is sufficient for the construction of the semiclassical recurrence function up to, in principle, infinite length. As in our recent work the recurrence signal is inverted by means of a high res

Nikolaos Kidonakis

We review the resummation of threshold logarithms for heavy quark, dijet, direct photon, and W boson production cross sections in hadronic collisions. Beyond leading logarithms the resummed cross section is sensitive to the color exchange in the hard scattering. The resummation is formulated at next-to-leading logarithmic or higher accuracy in terms of anoma

Reggie Brown, Ljupco Kocarev

We propose a unified definition for synchronization. By example we show that the synchronization phenomena discussed in the dynamical systems literature can be described within the framework of this definition.

Brooke P. Skelton, William H. Waller, Richard F. Gelderman, Larry Brown

We present a spectrophotometric imaging study of the emission bubble N70 (DEM 301) in the Large Magellanic Cloud. N70 is approximately 100 pc in size with a nearly circular shell-like morphology. The nebular emission is powered by an uncertain combination of EUV photons, intense winds, and supernova shock waves from the central population of high-mass stars

S. I. Blinnikov, A. V. Kozyreva, I. E. Panchenko

We argue that a nonthermally looking spectrum of a gamma-ray burst (GRB) can be formed as a superposition of a set of thermal blackbody spectra. This superposition may be done by time integration which is present even in `time resolved&#39; GRB spectroscopy. A nonthermal spectrum can be obtained also by the space integration which should take place unless al

Shauna Sallmen, D. C. Backer, T. H. Hankins, D. Moffett

Simultaneous measurements of giant pulses from the Crab pulsar were taken at two widely spaced frequencies using the real-time detection of a giant pulse at 1.4 GHz at the Very Large Array to trigger the observation of that same pulse at 0.6 GHz at a 25-m telescope in Green Bank, WV. Interstellar dispersion of the signals provided the necessary time to commu

W. F. Chen

The two-dimensional chiral anomaly is calculated using differential regularization. It is shown that the anomaly emerges naturally in the vector and axial Ward identities on the same footing as the four-dimensional case. The vector gauge symmetry can be achieved by an appropriate choice of the mass scales without introducing the seagull term. We have analyze

Vadim Kaloshin

Consider a compact manifold M of dimension at least 2 and the space of C^r-smooth diffeomorphisms Diff^r(M). The classical Artin-Mazur theorem says that for a dense subset D of Diff^r(M) the number of isolated periodic points grows at most exponentially fast (call it the A-M property). We extend this result and prove that diffeomorphisms having only hyperbol

Jason D. Fiege, Ralph E. Pudritz

In Paper I (Fiege & Pudritz, 1999), we constructed models of filamentary molecular clouds that are truncated by a realistic external pressure and contain a rather general helical magnetic field. We address the stability of our models to gravitational fragmentation and axisymmetric MHD-driven instabilities. By calculating the dominant modes of axisymmetric in

Gautam Rupak, Noam Shoresh

The effective field theory (EFT) for a toy model of nucleons interacting via a short range and a long range Yukawa potential is presented. The scattering amplitude in the 1S0 channel is calculated up to NNLO using KSW power counting scheme. A particular expansion of the amplitude about the pole at low (imaginary) momentum is used to derive matching condition

D. W. Hess, J. W. Serene

We compare the quasiparticle band structure for a model insulator obtained from the fluctuation exchange approximation (FEA) with the eigenvalues of the corresponding density functional theory (DFT) and local density approximation (LDA). The discontinuity in the exchange-correlation potential for this model is small and the FEA and DFT band structures are in

Adam Epstein

We prove a refinement of the Fatou-Shishikura Inequality - that the total count of nonrepelling cycles of a rational map is less than or equal to the number of independent infinite forward critical orbits - from a suitable application of Thurston's Rigidity Theorem - the injectivity of $I-f_*$ on spaces of meromorphic quadratic differentials.

Hiroshi Goda, Masakazu Teragaito

Let $K$ be a hyperbolic knot in the 3-sphere. If $r$-surgery on $K$ yields a lens space, then we show that the order of the fundamental group of the lens space is at most $12g-7$, where $g$ is the genus of $K$. If we specialize to genus one case, it will be proved that no lens space can be obtained from genus one, hyperbolic knots by Dehn surgery. Therefore,

Dierk Schleicher

We continue the description of Mandelbrot and Multibrot sets and of Julia sets in terms of fibers which was begun in IMS preprints 1998/12 and 1998/13a. The question of local connectivity of these sets is discussed in terms of fibers and becomes the question of triviality of fibers. In this paper, the focus is on the behavior of fibers under renormalization

Dierk Schleicher

We give new proofs that the Mandelbrot set is locally connected at every Misiurewicz point and at every point on the boundary of a hyperbolic component. The idea is to show ``shrinking of puzzle pieces'' without using specific puzzles. Instead, we introduce fibers of the Mandelbrot set and show that fibers of certain points are ``trivial'', i.e., they consis

Lajos Diosi

In the past ten-fifteen years, stochastic models of continuous wave function collapse were being proposed to describe the continuous emergence of classicality from quantum. We advocate that the hybrid dynamics of canonically coupled quantum and classical systems is a more basic concept. Continuous collapse formalisms are obtained as special cases. To illustr

A. Emperador, M. Barranco, E. Lipparini, M. Pi

We have studied the structure and dipole charge density response of nanorings as a function of the magnetic field using local-spin density functional theory. Two small rings consisting of 12 and 22 electrons confined by a positively charged background are used to represent the cases of a narrow and a wide ring. The results are qualitatively compared with exp

Dierk Schleicher

A frequent problem in holomorphic dynamics is to prove local connectivity of Julia sets and of many points of the Mandelbrot set; local connectivity has many interesting implications. The intention of this paper is to present a new point of view for this problem: we introduce fibers of these sets, and the goal becomes to show that fibers are ``trivial'', i.e

Arno R. Bohm, Raymond Scurek, Sujeewa Wikramasekara

Decaying states can be represented by Gamow vectors with an exponential, asymmetric time evolution. This asymmetric evolution is a manifestation of irreversibility on the microphysical level. The Rigged Hilbert Space provides a mathematical theory.

Ansar Fayyazuddin, Douglas J. Smith

We write supersymmetry preserving conditions for infinite M5-branes intersecting on a (3+1)-dimensional space. In contrast to previously known solutions, these intersections are completely localized. We solve the equations for a particular class of configurations which in the near-horizon decoupling limit are dual to N_f = 2N_c Seiberg-Witten superconformal

Giovanni Settanni, Cristian Micheletti, Jayanth Banavar, Amos Maritan

An optimization technique is used to determine the pairwise interactions between amino acids in globular proteins. A numerical strategy is applied to a set of proteins for maximizing the native fold stability with respect to alternative structures obtained by gapless threading. The extracted parameters are shown to be very reliable for identifying the native

Rudy Wijnands, Michiel van der Klis

We have studied the correlated X-ray spectral and X-ray timing behavior of the X-ray transient XTE J1806-246 using data obtained with the proportional counter array onboard the Rossi X-ray Timing Explorer. In the X-ray color-color diagram two distinct patterns are traced out. The first pattern is a curved branch, which is observed during the rise and the dec

A. J. Bray, A. J. Briant, D. K. Jervis

The approach to equilibrium, from a nonequilibrium initial state, in a system at its critical point is usually described by a scaling theory with a single growing length scale, $\xi(t) \sim t^{1/z}$, where z is the dynamic exponent that governs the equilibrium dynamics. We show that, for the 2D XY model, the rate of approach to equilibrium depends on the ini

J. Kaluzny, B. J. Mochejska, K. Z. Stanek, M. Krockenberger

We undertook a long term project, DIRECT, to obtain the direct distances to two important galaxies in the cosmological distance ladder -- M31 and M33 -- using detached eclipsing binaries (DEBs) and Cepheids. While rare and difficult to detect, DEBs provide us with the potential to determine these distances with an accuracy better than 5%. The extensive photo

H. W. Braden, A. Marshakov, A. Mironov, A. Morozov

The compactification of five dimensional N=2 SUSY Yang-Mills (YM) theory onto a circle provides a four dimensional YM model with N=4 SUSY. This supersymmetry can be broken down to N=2 if non-trivial boundary conditions in the compact dimension, \phi(x_5 +R) = e^{2\pi i\epsilon}\phi(x_5), are imposed on half of the fields. This two-parameter (R,\epsilon) fami

E. K. Kudinov

It is proposed to used, as a basic property specifying the difference between an insulator and a conductor, a static phenomenon, namely the field effect which absent in the former, but present in the latter. The absence or present of the field effect is closely associated with the nature of the homogenious linear response to a static electric field. For an i

Hung Cheng, S. P. Li

In this paper, we study the renormalizability of the Standard Model in the Landau gauge. On the basis of the Ward-Takahashi identities, we derive exact expressions for the physical masses of the W and Z as well as the renormalized coupling constants in the theory. We show that it is impossible to make all these renormalized quantities finite. Thus the quantu

S. James Gates,, Tristan Hubsch, Sergei M. Kuzenko

Continuing the investigation of CNM (chiral-nonminimal) hypermultiplet nonlinear sigma-models, we propose extensions of the concept of the c-map which relate holomorphic functions to hyper-Kahler geometries. In particular, we show that a whole series of hyper-Kahler potentials can be derived by replacing the role of the 4D, N = 1 tensor multiplet in the orig

I. V. Dobrovolska, R. S. Tutik

The explicit semiclassical treatment of logarithmic perturbation theory for the nonrelativistic bound states problem is developed. Based upon $\hbar$-expansions and suitable quantization conditions a new procedure for deriving perturbation expansions for the one-dimensional anharmonic oscillator is offered. Avoiding disadvantages of the standard approach, ne

Sofia Feltzing, Gerard Gilmore, Rosemary F. G. Wyse

Analyses of their internal stellar kinematics imply that the dwarf spheroidal (dSph) companion galaxies to the Milky Way are among the most dark-matter dominated systems known. Should there be significant dark matter in the form of faint stars in these systems, the stellar luminosity function must be very different from that of a similar metallicity globular

E. Garrido, E. Moya de Guerra

The formalism to describe electron scattering reactions on two-neutron halo nuclei is developed. The halo nucleus is described as a three-body system (core+n+n), and the wave function is obtained by solving the Faddeev equations in coordinate space. We discuss elastic and quasielastic scattering using the impulse approximation to describe the reaction mechan

X. -Z. Yan, C. -R. Hu

The magnetic field effect in the Josephson tunneling between two d-wave superconductors are investigated. When the crystal orientation of one (or each) superconductor relative to the interface normal is such that midgap states exist at the interface, there is a component of the tunneling current due to the midgap states. For a junction with a flat {001}|{110

C. Bennemann, J. Baschnagel, W. Paul, K. Binder

We report results of molecular-dynamics simulations for a glassy polymer melt consisting of short, linear bead-spring chains. It was shown in previous work that this onset of the glassy slowing down is compatible with the predictions of the mode coupling theory. The physical process of `caging' of a monomer by its spatial neighbors leads to a distinct two st

E. Gabrielli, A. Gonzalez-Arroyo, C. Pena

We study N=1 supersymmetric SU(N) Yang-Mills theory on the lattice at strong coupling. Our method is based on the hopping parameter expansion in terms of random walks, resummed for any value of the Wilson parameter r in the small hopping parameter region. Results are given for the mesonic (2-gluino) and fermionic (3-gluino) propagators and spectrum.

A. Mourachkine

We use Ni and Zn impurities doped into Bi2212 to test the MS (Magnetic polaron - Spinon) model proposed earlier. We present electron-tunneling spectroscopy of pure, Ni- and Zn-doped Bi2212 single crystals below Tc using a break-junction technique. We show that the magnetic (Ni) and nonmagnetic (Zn) impurities doped into CuO2 planes affect both Tc and the den

Indranil Biswas, Mahan Mitra, Subhashis Nag

If $p : Y \to X$ is an unramified covering map between two compact oriented surfaces of genus at least two, then it is proved that the embedding map, corresponding to $p$, from the Teichm\"uller space ${\cal T}(X)$, for $X$, to ${\cal T}(Y)$ actually extends to an embedding between the Thurston compactification of the two Teichm\"uller spaces. Using this res

Donam Youm

We present the explicit forms of supergravity solutions for the various intersecting two BPS branes in eleven and ten dimensions, where one brane is localized at the delocalized other brane. Our partially localized supergravity solutions describe brane configurations in the near horizon region of the delocalized branes, where the two constituent branes meet

Christopher W. Churchill, Donald P. Schneider, Maarten Schmidt, James E. Gunn

The z=4.591 quasar PC 1415+3408 exhibits very strong associated metal-line absorption from the N V (1238,1242), Si IV (1393,1402), and C IV (1548,1550) doublets spanning the velocity interval -1700 < v < 0 km/s. Also present, are detached absorption troughs in N V and C IV spanning -5000 < v < -3000 km/s; this is characteristic of broad absorption line (BAL)

A. Emperador, M. Barranco, E. Lipparini, M. Pi

We have employed time-dependent local-spin density theory to analyze the multipole spin and charge density excitations recently found in GaAs-AlGaAs quatum dots [C. Sch\"uller et al, Phys. Rev. Lett {\bf 80}, 2673 (1998)]. The overall agreement between theory and experiment is good, identifying the angular momentum of the modes observed in the experiment. We

D. de Florian, M. Grazzini, Z. Kunszt

Inclusive associated production of a light Higgs boson (m_H < m_t) with one jet in pp collisions is studied in next-to-leading order QCD. Transverse momentum (p_T < 30 GeV) and rapidity distributions of the Higgs boson are calculated for the LHC in the large top-quark mass limit. It is pointed out that, as much as in the case of inclusive Higgs production, t

G. Risaliti, R. Maiolino, M. Salvati

We use hard X-ray data for an "optimal" sample of Seyfert 2 galaxies to derive the distribution of the gaseous absorbing column densities among obscured active nuclei in the local Universe. Of all Seyfert 2 galaxies in the sample, 75% are heavily obscured (N_H > 10^23 cm^-2) and about half are Compton thick (N_H > 10^24 cm^-2). Intermediate type 1.8-1.9 Seyf

M. Villar-Martin, C. Tadhunter, R. Morganti, D. Axon

We present high resolution, long-slit spectra of the jet-cloud interaction in the powerful southern radio galaxy PKS2250-41. We have resolved the emission lines into two main kinematic components: a broad component (FWHM \geq 900 km/s) and a narrow component (FWHM \leq 150 km/s). While the broad component is characterized by a low ionization level (with part

A. G. Moreira, M. M. Telo da Gama, M. E. Fisher

Criticality in a fluid of dielectric constant D that exhibits Ising-type behavior is studied as additional electrostatic (i.e., ionic) interactions are turned on. An exploratory perturbative calculation is performed for small ionicity as measured by the ratio of the electrostatic energy to the strength of the short-range nonionic (i.e., van der Waals) intera

P. C. Stichel

Gauging of space translations for nonrelativistic point particles in one dimension leads to general coordinate transformations with fixed Newtonian time. The minimal gauge invariant extension of the particle velocity requires the introduction of two gauge fields whose minimal self interaction leads to a Maxwellian term in the Lagrangean. No dilaton field is

Michael Gronau, Dan Pirjol

Three ways are compared of dealing with rescattering effects in $B^{\pm}\to K^0\pi^{\pm}$, in order to determine the weak phase $\gamma$ from these processes and $B^{\pm}\to K^{\pm}\pi^0$. We find that neglecting these contributions altogether may involve sizable errors in $\gamma$, depending on the rescattering amplitude and on the value of a certain measur

N. G. Evanson, J. R. Forshaw

We study the diffractive production of photons in gamma-p and gamma-gamma collisions. We specifically compute the rates for gamma*-p -> gamma-X and for gamma*-gamma* -> gamma-gamma, where X denotes the proton dissociation. We focus on the rates at large momentum transfers, -t >> Lambda^2, where we are most confident in the use of QCD perturbation theory. How

Daniel H. Lenz

This article is concerned with crossed products and their applications to random operators. We study the von Neumann algebra of a dynamical system using the underlying Hilbert algebra structure. This gives a particularly easy way to introduce a trace on this von Neumann algebra. We review several formulas for this trace, show how it comes as an application o

K. G. Chetyrkin, M. Steinhauser

The partial decay rate of the $Z$ boson into bottom quarks constitutes an important decay channel. This is mainly due to the virtual presence of the top quark in the loop diagrams giving rise to correction factors which are quadratic in the top quark mass. At one- and two-loop order it turned out that the leading term in the heavy-top expansion leads to very

V. A. Kudryavtsev, M. J. Lehner, C. D. Peak, T. B. Lawson

Measurements of the shapes of scintillation pulses produced by nuclear recoils, alpha particles and photons in NaI(Tl) crystals at visible energies of 10-100 keV have been performed in order to investigate possible sources of background in NaI(Tl) dark matter experiments and, in particular, the possible origin of the anomalous fast time constant events obser

Eduardo Eyras, Yolanda Lozano

We review the construction of the Kaluza-Klein monopole of the Type IIA theory in the most general case of a massive background, as well as its relation via T-duality with the Type IIB NS-5-brane. This last effective action is shown to be related by S-duality to the D5-brane effective action.

M. Beyer, W. Schadow, C. Kuhrts, G. Roepke

We derive three-body equations valid at finite densities and temperatures. These are based on the cluster mean field approach consistently including proper self energy corrections and the Pauli blocking. As an application we investigate the binding energies of triton and determine the Mott densities and momenta relevant for a many particle description of nuc

Reimer Kuehn, Ion-Olimpiu Stamatescu

We study a simple learning model based on the Hebb rule to cope with "delayed", unspecific reinforcement. In spite of the unspecific nature of the information-feedback, convergence to asymptotically perfect generalization is observed, with a rate depending, however, in a non- universal way on learning parameters. Asymptotic convergence can be as fast as that

Andrew Gould

Zaritsky & Lin have claimed detection of an intervening population of stars toward the Large Magellanic Cloud (LMC) which, they believe, could account for a substantial fraction of the observed microlensing events. I show that the observed time scales of these events imply that if such an intervening population were composed of ordinary stars that gave rise

G. Calucci, D. Treleani

The observation of double parton collisions by CDF has provided the first direct information on the structure of the proton in transverse space. The actual quantity which has been measured is the `effective cross section' $\sigma_{eff}$, which is related to the transverse size of the region where hard interactions are localized. The actual value which has be