August 1999 arXiv papers — page 3

T. Brandes, J. Inoue, A. Shimizu

We present theoretical results for superradiance, i.e. the collective coherent decay of a radiating system, in semiconductor structures. An optically active region can become superradiant if a strong magnetic field is applied. Pumping of electrons and holes at a rate T through coupling to external `reservoirs' leads to a novel kind of oscillations with f

K. Haule, J. Bonca, P. Prelovsek

Using recently developed Lanczos technique we study finite-temperature properties of the 2D Kondo lattice model at various fillings of the conduction band. At half filling the quasiparticle gap governs physical properties of the chemical potential and the charge susceptibility at small temperatures. In the intermediate coupling regime quasiparticle gap scale

M. Annunziato, P. Grigolini, J. Riccardi

We study the influence of a dissipation process on diffusion dynamics triggered by fluctuations with long-range correlations. We make the assumption that the perturbation process involved is of the same kind as those recently studied numerically and theoretically, with a good agreement between theory and numerical treatment. As a result of this assumption th

A. Maciolek, R. Evans, N. B. Wilding

The adsorption of a near-critical fluid confined in a slit pore is investigated by means of density functional theory and by Monte Carlo simulation for a Lennard-Jones fluid. Our work was stimulated by recent experiments for SF_6 adsorbed in a mesoporous glass which showed the striking phenomenon of critical depletion, i.e. the adsorption excess "Gamma&#

Satya N. Majumdar, Supriya Krishnamurthy, Mustansir Barma

We study the nonequilibrium phase transition in a model of aggregation of masses allowing for diffusion, aggregation on contact and fragmentation. The model undergoes a dynamical phase transition in all dimensions. The steady state mass distribution decays exponentially for large mass in one phase. On the contrary, in the other phase it has a power law tail

H. Wilhelm, S. Raymond, D. Jaccard, O. Stockert

The electrical resistivity rho(T) of single crystalline CeCu_5Au under pressure was measured in the temperature range 30mK<T<300K. Pressure suppresses the antiferromagnetic order (T_N=2.35K at ambient pressure) and drives the system into a non-magnetic heavy-fermion state above P_c=4.1(3)GPa. The electrical resistivity shows a deviation from a T^2 dependence

G. Jackeli, G. Japaridze

The one-dimensional Hubbard model with different on-site interactions is investigated by renormalization group technique. In the case of a 1/4-filled band the dynamical nonequivalence of sites leads to the appearance of Umklapp processes in the system and to the dynamical generation of a gap in the charge excitation spectrum for $U_{a}\not=U_{b}$, $U_{a}>0$

Shiro Kawabata

A novel quantum interference effect in disordered quasi-one-dimensional rings in the inhomogeneous magnetic field is reported. We calculate the canonical disorder averaged persistent current using the diagrammatic perturbation theory. It is shown that within the adiabatic regime the average current oscillates as a function of the geometric flux which is rela

Viviane M. de Oliveira, J. F. Fontanari, Peter F. Stadler

The mean number <N> of metastable states in higher order short-range spin glasses is estimated analytically using a variational method introduced by Tanaka and Edwards for very large coordination numbers. For lattices with small connectivities, numerical simulations do not show any significant dependence on the relative positions of the interacting spins on

V. A. Malyshev, A. Rodirguez, F. Dominguez-Adame

We analyze the effects of intersite energy correlations on the linear optical properties of one-dimensional disordered Frenkel exciton systems. The absorption line width and the factor of radiative rate enhancement are studied as a function of the correlation length of the disorder. The absorption line width monotonously approaches the seeding degree of diso

V. A. Malyshev, F. Dominguez-Adame

We analyze the peculiarities of the motional narrowing effect in disordered one-dimensional Frenkel chains with off-diagonal disorder, induced by uncorrelated Gaussian fluctuations in the positions of the host units. A clear difference in the scaling laws with respect to the magnitude of the positional disorder and the chain size is found, as compared to tho

A. Sawa, S. Kashiwaya, H. Obara, H. Yamasaki

The transport properties between ferromagnets and high-Tc superconductors are investigated in La0.67Sr0.33MnO3/YBa2Cu3O7-d (LSMO/YBCO)junctions in the geometry of cross-strip lines. The conductance spectra show zero-bias conductance peaks (ZBCP), reflecting the charge transport in the ab-plane. When an external magnetic field is applied to the junctions, the

D. J. Scalapino

The organizers of the Memorial Session for Herman Rietschel asked that I review some of the history of the interplay of superconductivity and spin fluctuations. Initially, Berk and Schrieffer showed how paramagnon spin fluctuations could suppress superconductivity in nearly-ferromagnetic materials. Following this, Rietschel and various co-workers wrote a num

M. J. Ledlow, F. N. Owen, J. A. Eilek

We present a comparison of the optical and radio properties of radio sources inside and outside the cores of rich clusters from combined samples of more than 380 radio sources. We also examine the nature of FR I and FR II host galaxies, and in particular, we illustrate the importance of selection effects in propagating the misconception that FR I&#39;s and F

Slavek M. Rucinski

Two sub-samples of blue, luminous contact systems from among 86 systems discovered in LMC by the MACHO project and classified as EB3 have been analyzed: a sub-sample of 29 extremely-blue systems (XB) with the observed colours V-R_C<-0.1 and a sub-sample of 36 moderately-blue (MB) systems with -0.1<V-R_C<0. To be so blue, the XB systems must be intrinsically

Long-long Feng, Zu-Gan Deng, Li-Zhi Fang

Recently, scale-scale correlations have been detected in the distributions of quasar&#39;s Ly$α$ absorption lines and the maps of cosmic temperature fluctuations. In this paper, we investigate the scale-scale correlations in galaxy distributions. Using samples of mass field given by N-body simulation, we first show that the scale-scale correlation of 2-D and

Stephane Rauzy, Martin Hendry

We present a new method for fitting peculiar velocity models to complete flux limited magnitude-redshifts catalogues, using the luminosity function of the sources as a distance indicator. The method is characterized by its robustness. In particular, no assumptions are made concerning the spatial distribution of sources and their luminosity function. Moreover

R. A. Méndez, D. Minniti

Using data derived from the deepest and finest angular resolution images of the universe yet acquired by astronomers at optical wavelengths using the Hubble Space Telescope (HST) in two postage-stamp sections of the sky (Williams et al. 1996a,b), plus simple geometrical and scaling arguments, we demonstrate that the faint blue population of point-source obje

David Burstein

The recent re-evaulation of the peculiar velocity field outside the Local Supercluster (Dekel et al. 1999, ApJ 522) has permitted a re-examination of the origins of the peculiar velocity field within the Local Supercluster using the Mark III Catalog of Galaxy Peculiar Velocities for spiral galaxies. It is shown that the large-scale coherent pattern of peculi

Matthew G. Baring, Frank C. Jones, Donald C. Ellison

There has recently been interest in the role of inverse bremsstrahlung, the emission of photons by fast suprathermal ions in collisions with ambient electrons possessing relatively low velocities, in tenuous plasmas in various astrophysical contexts. This follows a long hiatus in the application of suprathermal ion bremsstrahlung to astrophysical models sinc

L. Portinari, C. Chiosi

The abundance gradients and the radial gas profile of the Galactic disc are analysed by means of a model for the chemical evolution of galaxies. As one of the major uncertainties in models for galaxy evolution is the star formation (SF) process, various SF laws are considered,to assess the response of model predictions to the different assumptions. Only some

Michael A. Strauss

This introductory talk to the 1999 Victoria Conference on Large-Scale Flows will present the ``big questions&#39;&#39; which will be discussed in the conference: (a) Does the velocity field converge on the largest scales? (b) Why can&#39;t we agree on the value of beta? (c) How can we properly measure the small-scale velocity dispersion? (d) Just how complic

H. Hirashita

We discuss the time variation of dust-to-gas mass ratio in spiral galaxies using the multi-phase model of interstellar medium. The typical timescale of the phase change of an interstellar gas is $\sim 10^7$--$10^8$ yr in spiral galaxies. Since the phase transition changes the filling factor of the cold gas where the dust growth occurs, the dust growth rate v

A. Vecchi, S. Molendi, M. Guainazzi, F. Fiore

The spectrum of the 1.0-8.0 keV cosmic X-ray background (CXB) at galactic latitudes > 25 degrees has been measured using the BeppoSAX LECS and MECS instruments. The spectrum is consistent with a power-law of photon index 1.40 +/- 0.04 and normalization 11.7 +/- 0.5 photon cm^{-2} s^{-1} keV^{-1} sr^{-1} at 1 keV. Our results are in good agreement with previo

A. D. Karnik, S. K. Ghosh

Mid and far infrared maps of many Galactic star forming regions show multiple peaks in close proximity, implying more than one embedded energy sources. With the aim of understanding such interstellar clouds better, the present study models the case of two embedded sources. A radiative transfer scheme has been developed to deal with an uniform density dust cl

Antoinette Songaila, Esther M. Hu, Lennox L. Cowie, Richard G. McMahon

We report new limits on the Gunn-Peterson effect at a redshift near 5 using spectroscopic observations of the z = 5 Sloan Digital Sky Survey quasar, J033829.31+002156.3, made with the LRIS and HIRES spectrographs on the Keck telescopes. Lower resolution spectrophotometrically calibrated observations made with LRIS over the wavelength region 4500-9600 angstro

S. -H. Lee, C. Broholm, T. H. Kim, W. Ratcliff

Using inelastic magnetic neutron scattering we have discovered a localized spin resonance at 4.5 meV in the ordered phase of the geometrically frustrated cubic antiferromagnet $\rm ZnCr_2O_4$. The resonance develops abruptly from quantum critical fluctuations upon cooling through a first order transition to a co-planar antiferromagnet at $T_c=12.5(5)$ K. We

A. Udalski, I. Soszynski, M. Szymanski, M. Kubiak

We present the Catalog of Cepheids from the LMC. The Catalog contains 1333 objects detected in the 4.5 square degree area of central parts of the LMC. About 3.4*10^5 BVI measurements of these stars were collected during the OGLE-II microlensing survey. The Catalog data include period, BVI photometry, astrometry, and R_21, \phi_21 parameters of the Fourier de

A. R. Tumanyan, N. Z. Akopov, Z. G. Guiragossian, Z. N. Akopov

The concept of large-radius multistage coaxial cyclotrons having separated orbits is described, to generate proton beams of 120-2000 MeV energy at tens of GW pulsed and hundreds of MW in continuous beam power operation. Accelerated beam losses must be less than 0.1 W/m for the intercepted average beam power linear density. The concept is inherently configure

Marcelo Gleiser, Andrew Sornborger

Long-lived localized field configurations such as breathers, oscillons, or more complex objects naturally arise in the context of a wide range of nonlinear models in different numbers of spatial dimensions. We present a numerical method, which we call the {\it adiabatic damping method}, designed to study such configurations in small lattices. Using 3-dimensi

Andrey A. Sukhorukov

We study quadratic solitons supported by two- and three-wave parametric interactions in chi-2 nonlinear media. Both planar and two-dimensional cases are considered. We obtain very accurate, &#39;almost exact&#39;, explicit analytical solutions, matching the actual bright soliton profiles, with the help of a specially-developed approach, based on analysis of

Saharon Shelah

Here we deal with some problems posed by Matet. The first section deals with the existence of stationary subsets of [lambda]^{<kappa} with no unbounded subsets which are not stationary, where, of course, kappa is regular uncountable less or equal than lambda. In the second section we deal with the existence of such clubs. The proofs are easy but the result s

Ziv Shami, Saharon Shelah

In a countable superstable NDOP theory, the existence of a rigid aleph_epsilon-saturated model implies the existence of 2^lambda rigid aleph_epsilon-saturated models of power lambda for every lambda>2^{aleph_0}.

Paul C. Eklof, Saharon Shelah

We prove that it is consistent that there is a non-reflexive Whitehead group, in fact one whose dual group is free. We also prove that it is consistent that there is a group A such that Ext(A,Z) is torsion and Hom(A,Z)=0. As an application we show the consistency of the existence of new co-Moore spaces.

Wilderich Tuschmann

Our main result asserts that for any given numbers C and D the class of simply connected closed smooth manifolds of dimension m<7 which admit a Riemannian metric with sectional curvature bounded in absolute value by C and diameter uniformly bounded from above by D contains only finitely many diffeomorphism types. Thus in these dimensions the lower positive b

R. Myrzakulov

A connection between differential geometry and soliton equations is discussed

Matthias Burkardt

In these notes, the transverse ($\perp$) lattice approach is presented as a means to control the $k^+\to 0$ divergences in light-front QCD. Technical difficulties of both the canonical compact formulation as well as the non-compact formulation of the $\perp$ lattice motivate the color-dielectric formulation, where the link fields are linearized.

Bahniman Ghosh, Sunil Mukhi

We examine the behaviour of Killing spinors on AdS5 under various discrete symmetries of the spacetime. In this way we discover a number of supersymmetric orbifolds, reproducing the known ones and adding a few novel ones to the list. These orbifolds break the SO(4,2) invariance of AdS5 down to subgroups. We also make some comments on the non-compact Stiefel

Nikolay V. Dokholyan, Youngki Lee, Sergey V. Buldyrev, Shlomo Havlin

We present a scaling hypothesis for the distribution function of the shortest paths connecting any two points on a percolating cluster which accounts for {\it (i)} the effect of the finite size of the system, and {\it (ii)} the dependence of this distribution on the site occupancy probability $p$. We test the hypothesis for the case of two-dimensional percol

N. Zekri, K. Bennabi, S. Maarouf

We investigate the localization observed recently for locally non-hermitian Hamiltonians by studying the effect of the amplification on the scaling behavior of the transmission and reflection phases in 1D periodic chains of $δ$-potentials. The amplification here is represented by an imaginary term added to the on-site potential. It is found that both phases

S. M. Soskin

The main subject of the paper is an escape from a multi-well metastable potential on a time-scale of a formation of the quasi-equilibrium between the wells. The main attention is devoted to such ranges of friction in which an external saddle does not belong to a basin of attraction of an initial attractor. A complete rigorous analysis of the problem for the

Y. Jiang, T. Lookman, A. Saxena

Within a coupled-field Ginzburg-Landau model we study analytically phase separation and accompanying shape deformation on a two-phase elastic membrane in simple geometries such as cylinders, spheres and tori. Using an exact periodic domain wall solution we solve for the shape and phase ordering field, and estimate the degree of deformation of the membrane. T

X. S. Rao, C. K. Ong, B. B. Jin, C. Y. Tan

We have studied an anomalous microwave (mw) response of superconducting YBa_{2}Cu_{3}O_{7-delta} (YBCO) microstrip resonators in the presence of a weak dc magnetic field, H_{dc}. The surface resistance (R_{s}) and reactance (X_{s}) show a correlated non-monotonic behaviour as a function of H_{dc}. R_{s} and X_{s} were found to initially decrease with elevate

Noam Soker

We examine the flow from asymptotic giant branch (AGB) stars when along a small solid angle the optical depth due to dust is very large. We consider two types of flows. In the first, small cool spots are formed on the surface of slowly rotating AGB stars. During the last AGB phase when mass loss rate is high, the dust shields the region above it from the ste

T. T. Nguyen, I. Rouzina, B. I. Shklovskii

A theory of condensation and resolubilization of a dilute DNA solution with growing concentration of multivalent cations, N is suggested. It is based on a new theory of screening of a macroion by multivalent cations, which shows that due to strong cation correlations at the surface of DNA the net charge of DNA changes sign at some small concentration of cati

J. L. Boldo, L. P. Colatto, M. A. De Andrade, O. M. Del Cima

A systematic algorithm to derive superpropagators in the case of either explicitly or spontaneously broken supersymmetric three-dimensional theories is presented. We discuss how the explicit breaking terms that are introduced at tree-level induce 1-loop radiative corrections to the effective action. We also point out that the renormalisation effects and the

Liliya L. R. Williams

Several recent studies show that bright, intermediate and high redshift optically and radio selected QSOs are positively correlated with nearby galaxies on a range of angular scales up to a degree. Obscuration by unevenly distributed Galactic dust can be ruled out as the cause, leaving weak statistical lensing as the physical process responsible. However the

J. A. Oller

We have studied the strongly interacting $W_L W_L \to W_L W_L$ I=L=0 partial wave amplitude making use of effective chiral Lagrangians. The Higgs boson is explicitly included and the N/D method is used to unitarize the amplitude. We recover the chiral perturbative expansion at next to leading order for low energies. The cases $m_H<< 4πv$ and $m_H>> 4 πv$ are

J. de Boer, J. Evslin, M. B. Halpern, J. E. Wang

We find new duality transformations which allow us to construct the stress tensors of all the twisted sectors of any orbifold A(H)/H, where A(H) is the set of all current-algebraic conformal field theories with a finite symmetry group H \subset Aut(g). The permutation orbifolds with H = Z_λand H = S_3 are worked out in full as illustrations but the general f

Csaba Csaki, Yuri Shirman

We present static solutions to Einstein&#39;s equations corresponding to branes at various angles intersecting in a single 3-brane. Such configurations may be useful for building models with localized gravity via the Randall-Sundrum mechanism. We find that such solutions may exist only if the mechanical forces acting on the junction exactly cancel. In additi

N. D. Hari Dass

Techniques of Atom trapping and laser cooling have proved to be very important tools in probing many aspects of fundamental physics. In this talk I wish to present ideas on how they may used to settle certain issues in the foundational aspects of quantum mechanics on the one hand and about some quantum gravitational interactions of matter that violate parity

Daniel S. Abrams, Colin P. Williams

We discuss quantum algorithms that calculate numerical integrals and descriptive statistics of stochastic processes. With either of two distinct approaches, one obtains an exponential speed increase in comparison to the fastest known classical deterministic algorithms and a quadratic speed increase in comparison to classical Monte Carlo (probabilistic) metho

Frank Julicher

We review the properties of biological motor proteins which move along linear filaments that are polar and periodic. The physics of the operation of such motors can be described by simple stochastic models which are coupled to a chemical reaction. We analyze the essential features of force and motion generation and discuss the general properties of single mo

Dmitry Khavinson, John E. McCarthy, Harold S. Shapiro

We consider the problem of finding the best harmonic or analytic approximant to a given function. We discuss when the best approximant is unique, and what regularity properties the best approximant inherits from the original function. All our approximations are done in the mean with respect to Lebesgue measure in the plane or higher dimensions.

Wen-Ching Li, Hiren Maharaj

The number A(q) is the upper limit of the ratio of the maximum number of points of a curve defined over $\Fq$ to the genus. By constructing class field towers with good parameters we present improvements of lower bounds of A(q) for q an odd power of a prime.

Alan Hopenwasser, Justin R. Peters, Stephen C. Power

A nest representation of a strongly maximal TAF algebra $A$ is a representation $π$ for which $\operatorname{Lat} π(A) is totally ordered. We prove that if the spectrum of $A$ is totally ordered, or if $\operatorname{Lat} π(A)$ contains an atom, then $\operatorname{ker} π$ is a meet irreducible ideal.

Roland Auer

A general type of ray class fields of global function fields is investigated. The systematic computation of their genera leads to new examples of curves over finite fields with comparatively many rational points.

E. Minguzzi

We show how to use the method of orthogonal polynomials for integrating, in the planar approximation, the partition function of one-matrix models with a potential with even or odd vertices, or any combination of them.

Pietro Antonio Grassi

We study the renormalization of non-semisimple gauge models quantized in the `t Hooft-background gauge to all orders. We analyze the normalization conditions for masses and couplings compatible with the Slavnov-Taylor and Ward-Takahashi Identities and with the IR constraints. We take into account both the problem of renormalization of CKM matrix elements and

H. Jung

A solution of the CCFM equation for a description of both the structure function $F_2$ and the cross section of forward jet production as measured by the HERA experiments is obtained on the basis of the parton level Monte Carlo program SMALLX. The treatment of the non - Sudakov form factor and the so - called &#34;consistency constraint&#34; are discussed. F

E. Oset, A. Hosaka, J. C. Nacher, M. Oka

We report on recent progress on the chiral unitary approach, which is shown to have a much larger convergence radius than ordinary chiral perturbation theory, allowing one to reproduce data for meson meson interaction up to 1.2 GeV and meson baryon interaction up to the first baryonic resonances. Applications to physical processes so far unsuited for a stand

J. A. Oller, E. Oset

We study the vector and scalar meson-meson amplitudes up to \sqrt{s}\lesssim 1.4 GeV and their associated spectroscopy. The study has been done considering jointly the N/D method, Chiral Symmetry and implications from large N_c QCD. The N/D method provides us with the way to unitarize the tree level amplitudes constructed in agreement with Chiral Symmetry an

J. A. Oller, F. Guerrero, E. Oset, J. R. Pelaez

A non-perturbative method which combines constraints from chiral symmetry breaking and coupled channel unitarity is used to describe meson-meson interactions up to \sqrt{s}\lesssim 1.2 GeV, extending in this way the range of applicability of the information contained in Chiral Perturbation Theory (χPT), since this perturbative series is typically restricted

Prem P. Srivastava

Some basic topics in the light-front (LF) quantization of relativistic field theory are reviewed. It is argued that the LF quantization is equally appropriate as the conventional one and that they lead, assuming the micro- causality principle, to the same physical content. This is confirmed in the studies on the LF of the spontaneous symmetry breaking (SSB),

N. D. Hari Dass

We have developed the techniques necessary for a numerical simulation of d=3 SU(2) Lattice Gauge theories in the dual formulation as originally developed by Anishetty et al . These include updating techniques that preserve the constrained configuration space, efficient evaluation of 6-j symbols and a certain problem associated with the positive indefinitenes

Robert A Smith, Beccy S Handy, Vinay Ambegaokar

We present calculations of the upper critical field in superconducting films as a function of increasing disorder (as measured by the normal state resistance per square). In contradiction to previous work, we find that there is no anomalous low-temperature positive curvature in the upper critical field as disorder is increased. We show that the previous pred

K. Kiran Kumar, K. L. Sebastian

We analyze the free energy for translocation of a polymer from the outside of a spherical vesicle to the inside. The process is assumed to be driven by the adsorption of the polymer on the inner surface of the vesicle. We argue that in the case where the polymer is adsorbed on the outer surface too, the entropic barrier for translocation is absent. We analyz

O. Derzhko, J. Richter, V. Derzhko

The spin-1/2 transverse XY chain with correlated disorder may exhibit the nonzero averaged transverse magnetization at zero averaged transverse field. We discuss this peculiarity connected with asymmetry in the density of states and induced by the correlated disorder analysing the moments of the density of states.

M. Dube, P. C. E. Stamp

The low-energy behaviour of 2 coupled nanomagnets or 2 coupled SQUIDs, interacting with their environment, can be described by the model of a ``Pair or Interacting Spins Coupled to an Environmental Sea&#39;&#39; (PISCES). These physical systems can then be used for a measurement operation in which system, apparatus and environment are all treated quantum mec

M. Dube, P. C. E. Stamp

We investigate the motion of a domain wall in the presence of a dynamical hyperfine field. At temperature T high compared to the hyperfine coupling, the nuclear spins create a spatially random potential landscape, with dynamics dictated by the nuclear relaxation time $T_2$. The distribution of the domain wall relaxation times (both in the thermal and quantum

David M. Sedrakian, Ashot Zh. Khachatrian

Recurrent representations for an electron transmission and reflection amplitudes for a one-dimensional chain are obtained. The linear differential equations for scattering amplitudes of an arbitrary potential are found.

D. P. Kirilova, M. V. Chizhov

We discuss a mechanism for producing baryon density perturbations during inflationary stage and study the evolution of the baryon charge density distribution in the framework of the low temperature baryogenesis scenario. This mechanism may be important for the large scale structure formation of the Universe and particularly, may be essential for understandin

Sorin Solomon, Gerard Weisbuch

We introduce the simplest model which relates the emergence of collective social/economic phenomena to the existence of a (possibly self-organized) percolation transition. We suggest a series of extensions to financial, economic, political systems.

H. S. Egawa, S. Horata, N. Tsuda, T. Yukawa

The phase transition of 4D simplicial quantum gravity coupled to U(1) gauge fields is studied using Monte-Carlo simulations. The phase transition of the dynamical triangulation model with vector field ($N_{V}=1$) is smooth as compared with the pure gravity($N_{V}=0$). The node susceptibility ($χ$) is studied in the finite size scaling method. At the critical

Peter Mattsson

We note that S-matrix/conserved charge identities in affine Toda field theories of the type recently noted by Khastgir can be put on a more systematic footing. This makes use of a result first found by Ravanini, Tateo and Valleriani for theories based on the simply-laced Lie algebras (A,D and E) which we extend to the nonsimply-laced case. We also present th

The E864 Collaboration, L. Evan Finch

We present measurements of the production of stable light nuclei for mass number A<=7, of strongly decaying states He(5) and Li(5) and of the hypernucleus H(3,lambda). We also examine trends in the production of these multibaryon states as a function of kinematic variables and properties of these states including strangeness content.

Gregorio Malajovich, Jorge P. Zubelli

Graeffe iteration was the choice algorithm for solving univariate polynomials in the XIX-th and early XX-th century. In this paper, a new variation of Graeffe iteration is given, suitable to IEEE floating-point arithmetics of modern digital computers. We prove that under a certain generic assumption the proposed algorithm converges. We also estimate the erro

Thomas L. Clarke

A attempt at a quantum algorithm for solving NP problems is presented. Now withdrawn because some crucial operators were not unitary.

Gregorio Malajovich, Jorge P. Zubelli

A new version of the Graeffe algorithm for finding all the roots of univariate complex polynomials is proposed. It is obtained from the classical algorithm by a process analogous to renormalization of dynamical systems. This iteration is called Renormalized Graeffe Iteration. It is globally convergent, with probability 1. All quantities involved in the compu

Mauri Miettinen, Antti J. Niemi, Yuri Stroganov

We inspect the excitation energy spectrum of a confining string in terms of solitons in an effective field theory model. The spectrum can be characterized by a spectral function, and twisting and bending of the string is manifested by the invariance of this function under a duality transformation. Both general considerations and numerical simulations reveal

Elisa Di Pietro, Jacques Demaret

Quintessence is often invoked to explain the universe acceleration suggested by the type Ia supernovae observations. The aim of this letter is to study the validity of using a constant equation of state for quintessence models. We shall show that this hypothesis strongly constraint the form of the scalar potential.

Donam Youm

We obtain various solutions for D=4 dipoles and their bound states whose U(1) fields originate from various form fields in the effective string theories. We oxidize such dipole solutions to D=10 to obtain delocalized supergravity solutions for the brane/anti-brane pairs and their bound states. We speculate on generalized harmonic superposition rules for supe

M. V. Moskalets, P. Singha Deo

We predict a non-monotonous temperature dependence of the persistent currents in a ballistic ring coupled strongly to a stub in the grand canonical as well as in the canonical case. We also show that such a non-monotonous temperature dependence can naturally lead to a $ϕ_0/2$ periodicity of the persistent currents, where $ϕ_0$=h/e. There is a crossover tempe

M. J. Coe, J. A. Orosz

This paper presents analysis and interpretation of OGLE photometric data of four X-ray binary pulsar systems in the Small Magellanic Cloud: 1WGA J0054.9-7226, RX J0050.7-7316, RX J0049.1-7250, and 1SAX J0103.2-7209. In each case, the probable optical counterpart is identified on the basis of its optical colours. In the case of RX J0050.7-7316 the regular mod

Y. Kurihara, M. Kuroda, D. Schildknecht

A recently suggested high-energy Born-form representation of the one-loop helicity amplitudes for e^+e^- to W^+W^- is supplemented by including W^+- decay and hard-photon radiation. Results for the differential and the total cross section for e^+e^- to W^+W^- to 4 fermions + gamma are given for the high-energy region of sqrt(s) > 500 GeV.

Martin Bojowald, Thomas Strobl

The group theoretical quantization scheme is reconsidered by means of elementary systems. Already the quantization of a particle on a circle shows that the standard procedure has to be supplemented by an additional condition on the admissibility of group actions. A systematic strategy for finding admissible group actions for particular subbundles of cotangen

Herbert Schoeller, Jürgen König

We develop a perturbative renormalization-group method in real time to describe nonequilibrium properties of discrete quantum systems coupled linearly to an environment. We include energy broadening and dissipation and develop a cutoff-independent formalism. We present quantitatively reliable results for the nonlinear conductance in the mixed-valence and emp

M. Effenberger, U. Mosel

In a transport model that combines initial state interactions of the photon with final state interactions of the produced particles we present a calculation of inclusive photoproduction of mesons in nuclei in the energy range from 1 to 7 GeV. We give predictions for the photoproduction cross sections of pions, etas, kaons, antikaons, and $π^+π^-$ invariant m

T. A. Lahde, C. Nyfalt, D. O. Riska

The M1 decay widths of charm and bottom mesons and their excited states are sensitive to the relativistic aspect of the quark current operators and obtain a significant contribution from the interaction current that is associated with the scalar confining interaction between heavy quarks ($Q$) and light antiquarks ($\bar q$). Consequently they provide direct

D. C. Cabra, A. De Martino, A. Honecker, P. Pujol

We study zero-temperature Hubbard chains with periodically modulated hopping at arbitrary filling n and magnetization m. We show that the magnetization curves have plateaux at certain values of m which depend on the periodicity p and the filling. At commensurate filling n a charge gap opens and then magnetization plateaux correspond to fully gapped situation

V. A. Sablikov, S. V. Polyakov, M. Buttiker

We investigate the distribution of the electron density and the potential in a quantum wire coupled to reservoirs, treating this structure as a unified quantum system and taking into account the Coulomb interaction of electrons. The chemical potential difference that exists between a decoupled, isolated quantum wire and the reservoirs gives rise to charge tr

Tatiana A. Ivanova, Alexander D. Popov

We describe constructing solutions of the field equations of Chern-Simons and topological BF theories in terms of deformation theory of locally constant (flat) bundles. Maps of flat connections into one another (dressing transformations) are considered. A method of calculating (nonlocal) dressing symmetries in Chern-Simons and topological BF theories is form

Xiao-Gang Wen

Continuous transitions between states with the {\em same} symmetry but different topological orders are studied. Clean quantum Hall (QH) liquids with neutral quasiparticles are shown to have such transitions. For clean bilayer (nnm) states, a continous transition to other QH states (including non-Abelian states) can be driven by increasing interlayer repulsi

B. J. Mochejska, L. M. Macri, D. D. Sasselov, K. Z. Stanek

We investigate the influence of blending on the Cepheid distance scale. Blending is the close association of a Cepheid with one or more intrinsically luminous stars. High-resolution HST images are compared to our ground-based data, obtained as part of the DIRECT project, for a sample of 22 Cepheids in the M31 galaxy. The average (median) V-band flux contribu

S. J. van Enk, H. J. Kimble

We calculate exact 3-D solutions of Maxwell equations corresponding to strongly focused light beams, and study their interaction with a single atom in free space. We show how the naive picture of the atom as an absorber with a size given by its radiative cross section $σ=3λ^{2}/2π$ must be modified. The implications of these results for quantum information p

Andrew G. White, Daniel F. V. James, Philippe H. Eberhard, Paul G. Kwiat

Using a spontaneous-downconversion photon source, we produce true non-maximally entangled states, i.e., without the need for post-selection. The degree and phase of entanglement are readily tunable, and are characterized both by a standard analysis using coincidence minima, and by quantum state tomography of the two-photon state. Using the latter, we experim

Oscar Bolina

You will find here a number of (mostly) elementary physics problems dealing mainly with uniform motion kinematics. In preparing this collection I have tried to create original situations that could help bring motivation to an introductory course. You are welcome to suggest improvements and ... provide solutions!

Jin-Hee Yoon, Cheuk-Yin Wong

In processes involving Coulomb-type initial- and final-state interactions, the Gamow factor has been traditionally used to take into account these additional interactions. The Gamow factor needs to be modified when the magnitude of the effective coupling constant increases or when the velocity increases. For the production of a pair of particles under their

K. Nakayama, H. F. Arellano, J. W. Durso, J. Speth

The pp -> pp eta&#39; reaction is investigated within a relativistic meson-exchange model of hadronic interactions. We explore the role of nucleonic and mesonic, as well as the N* resonance currents, in producing eta&#39; mesons. In order to learn more about the production mechanisms, new measurements in the energy region far from the threshold are required.

Agata Olariu

In this paper we have analyzed samples of Neolithic ceramics from Cucuteni-Scanteia - Vaslui county and Neolithic and Dacian ceramics from Magurele - Bucharest, by the method of neutron activation analysis. The following elements have been observed: Fe, K, La, Mn, Na, Sc and Sm. It has been noticed a relative and a slight clusterization of the analyzed items