September 2000 arXiv papers — page 2

Fernando Martinez-Vidal

Time-dependent B0-antiB0 flavor oscillations and B0 and B+ lifetimes are studied in a sample of fully reconstructed B mesons collected with the BaBar detector, running at the PEP-II asymmetric e+e- B Factory with center-of-mass energies near the Upsilon(4S) resonance. This is the first time that time-dependent mixing and lifetime measurements have been perfo

Volker Perlick

In a general-relativistic spacetime (Lorentzian manifold), gravitational lensing can be characterized by a lens map, in analogy to the lens map of the quasi-Newtonian approximation formalism. The lens map is defined on the celestial sphere of the observer (or on part of it) and it takes values in a two-dimensional manifold representing a two-parameter family

Therese Biedl, Erik Demaine, Martin Demaine, Sylvain Lazard

It has recently been shown that any simple (i.e. nonintersecting) polygonal chain in the plane can be reconfigured to lie on a straight line, and any simple polygon can be reconfigured to be convex. This result cannot be extended to tree linkages: we show that there are trees with two simple configurations that are not connected by a motion that preserves si

Lawrence C. Paulson

Manna and Waldinger's theory of substitutions and unification has been verified using the Cambridge LCF theorem prover. A proof of the monotonicity of substitution is presented in detail, as an example of interaction with LCF. Translating the theory into LCF's domain-theoretic logic is largely straightforward. Well-founded induction on a complex orde

Yong Xiao, Zena M. Ariola, Michel Mauny

Recent years have seen an increasing need of high-level specification languages and tools generating code from specifications. In this paper, we introduce a specification language, {\splname}, which is tailored to the writing of syntactic theories of language semantics. More specifically, the language supports specifying primitive notions such as dynamic con

Matthew Huntbach

Aldwych is proposed as the foundation of a general purpose language for parallel applications. It works on a rule-based principle, and has aspects variously of concurrent functional, logic and object-oriented languages, yet it forms an integrated whole. It is intended to be applicable both for small-scale parallel programming, and for large-scale open system

Wei Chen, Kazuo Hida, B. C. Sanctuary

The magnetization plateaus of $p$-merized $S=1/2$ XXZ chains are studied for general values of $p$. Two plateau-non-plateau critical lines and one plateau-plateau critical line are found for each value of $p$. The universality class of the plateau-non-plateau transition belongs to Brezinskii-Kosterlitz-Thouless (BKT) type and that of the plateau-plateau tran

Orion Ciftja, Siu A Chin, Francesco Pederiva

Many ground state studies of $^4$He using a shadow wave function with an inverse fifth power McMillan particle-particle correlation function have yielded radial distribution functions with misplaced peaks. It has been conjectured that this is due to the specific choice of the McMillan correlation function. However, beyond the use of fully optimized two-parti

Weiqun Peng, Paul M. Goldbart

Certain density correlators, measurable via various experimental techniques, are studied in the context of the vulcanization transition. It is shown that these correlators contain essential information about both the vulcanization transition and the emergent amorphous solid state. Contact is made with various physical ingredients that have featured in experi

Chang-Soo Park, Anupam Garg

We investigate the topological quenching of spin tunneling in Mn_12-acetate molecules with an applied magnetic field along the hard axis. The model Hamiltonian describing this system has a fourth-order term due to the tetragonal anisotropy. We treat this model using the discrete phase integral formalism in which the Schrodinger equation corresponding to the

Viktor A. Sverdlov, Daniel M. Kaplan, Alexander N. Korotkov, Konstantin K. Likharev

Numerical modeling of correlated single-electron tunneling in uniform 2D arrays of small conducting islands separated by tunnel junctions shows the possiblility of soliton-antisoliton avalanches. Though the time duration of any avalanche, and the total charge $ΔQ = ne$ transferred across the array during the avalanche, are always finite, in arrays with lengt

Yoshihiko Togawa, Ryuichi Abiru, Katsuya Iwaya, Haruhisa Kitano

We studied the conduction noise spectrum in the vortex state of a high-temperature superconductor, Bi2Sr2CaCu2Oy, subject to a uniform driving force. Two characteristic features, a broadband noise (BBN) and a narrow-band noise (NBN), were observed in the vortex-solid phase. The origin of the large BBN was determined to be plastic motion of the vortices, wher

Claudio Brangian, Walter Kob, Kurt Binder

We use Monte Carlo simulations to study the static and dynamical properties of a Potts glass with infinite range Gaussian distributed exchange interactions for a broad range of temperature and system size up to N=2560 spins. The results are compatible with a critical divergence of the relaxation time tau at the theoretically predicted dynamical transition te

M. A. Martin-Delgado, J. Rodriguez-Laguna, G. Sierra

We reformulate the density matrix renormalization group method (DMRG) in terms of a single block, instead of the standard left and right blocks used in the construction of the superblock. This version of the DMRG, which we call the puncture renormalization group (PRG), makes easy and natural the extension of the DMRG to higher dimensional lattices. To test n

P. Paci, C. Grimaldi, L. Pietronero, E. Cappelluti

High-$T_c$ superconductors have Fermi energies $E_F$ much smaller than conventional metals comparable to phonon frequencies. In such a situation nonadiabatic effects are important. A generalization of Eliashberg theory in the nonadiabatic regime has previously been shown to reproduce some anomalous features of the high-$T_c$ superconductors as for istance th

J. M. Zuo, J. Tao

Electron microdiffraction study of phase transition in La2/3Ca1/3MnO3 revealed temperature dependent (h+1/2,0,l) diffraction spots. Their intensity peaks at Tc. Quantitative electron diffraction intensity analysis shows that they come from nanometer-sized domains with modulated transverse atomic displacements in the orthorhombic a-c plane, which has two type

Shun-ichiro Koh

We calculate a grand partition function of the attractive Bose gas in the infinite space within some approximations. Using the idea of the Yang-Lee zeros, it is proved that the gas-liquid condensation occurs before the conventional condition of the Bose-Einstein condensation is satisfied. Further, it is pointed out that Bosons with a zero momentum play a rol

Shin-Ichi Ikeda, Naoki Shirakawa, Hiroshi Bando, Youiti Ootuka

We present the first systematic study on polycrystalline Sr2MoO4 as an electronic analogue to the spin-triplet superconductor Sr2RuO4. The Pauli paramagnetic susceptibility and metallic behaviors of specific heat and electrical resistivity have been observed. The density of states at the Fermi level D(EF) deduced from the results is about three times smaller

F. Milde, R. A. Roemer, M. Schreiber

We study the three-dimensional Anderson model of localization with anisotropic hopping, i.e., weakly coupled chains and weakly coupled planes. In our extensive numerical study we identify and characterize the metal-insulator transition by means of the transfer-matrix method and energy level statistics. Using high accuracy data for large system sizes we estim

B. Jackson, C. S. Adams

We utilize a two-gas model to simulate collective oscillations of a Bose-Einstein condensate at finite temperatures. The condensate is described using a generalized Gross-Pitaevskii equation, which is coupled to a thermal cloud modelled by a Monte Carlo algorithm. This allows us to include the collective dynamics of both the condensed and non-condensed compo

T. Antal, M. Droz, J. Magnin, A. Pekalski

A kinetic Ising model description of Liesegang phenomena is studied using Monte Carlo simulations. The model takes into account thermal fluctuations, contains noise in the chemical reactions, and its control parameters are experimentally accessible. We find that noisy, irregular precipitation takes place in dimension d=2 while, depending on the values of the

I. M. Sokolov

We discuss a problem of optimization of the energetic efficiency of a simple rocked ratchet. We concentrate on a low-temperature case in which the particle's motion in a ratchet potential is deterministic. We show that the energetic efficiency of a ratchet working adiabatically is bounded from above by a value depending on the form of ratchet potential.

Carlo M. Carbonaro, Vincenzo Fiorentini, Fabio Bernardini

The E' center is a paradigmatic radiation-induced defect in SiO2 whose peculiar EPR and hyperfine activity has been known since over 40 years. This center has been traditionally identified with a distorted, positively-charged oxygen vacancy V_O+. However, no direct proof of the stability of this defect has ever been provided, so that its identification i

M. V. Mostovoy, J. Knoester, D. I. Khomskii

We argue that in the quarter-filled ladder compound NaV_2O_5 the quasi-one-dimensional spin system is strongly coupled to a low-energy antiferroelectric mode of the excitonic type. This mode results from the interplay between the electron hopping along the rungs of the vanadium two-leg ladders and the Coulomb repulsion between electrons. The charge ordering

J. T. Chalker, N. Read, V. Kagalovsky, B. Horovitz

We study the universality class for localization which arises from models of non-interacting quasiparticles in disordered superconductors that have neither time-reversal nor spin-rotation symmetries. Two-dimensional systems in this category, which is known as class D, can display phases with three different types of quasiparticle dynamics: metallic, localize

G. George Batrouni, Alex Hansen, Jean Schmittbuhl

We model numerically the partial normal contact of two elastic rough surfaces with highly correlated asperities. Facing surfaces are unmated and described as self-affine with a Hurst exponent H. The numerical algorithm is based on Fourier acceleration and allows efficient simulation of very large systems. The force, F, versus contact area, A, characteristics

M. V. Eremin, S. I. Nikitin, S. Yu. Prosvirnin, N. I. Silkin

Optical absorption spectra of Cr$^{3+}$-Cr$^{2+}$ pair center in KZnF$_{3}$:Cr$^{3+}$,Cr$^{2+}$ crystal were investigated in wide temperature range. Broad band at 30800 cm$^{-1}$ is attributed to cation-cation (e_g)-electron transfer transition. Narrow lines with maxima at 16720 cm$^{-1}$ and 19880 cm$^{-1}$ have been assigned to purely electronic exchange-i

J. Camassel, L. A. Falkovsky, N. Planes

We report a detailed experimental and theoretical investigation of the effect of residual strain, and strain relaxation, which manifests itself at the Si/SiO$_{2}$ interfaces in commercial silicon-on-insulator (SOI) wafers. SOI material is made of a single-crystal silicon overlayer (SOL) on top of an insulator (buried SiO$_{2}$ layer) sitting on a handle sil

Yasuhiro Fujii

A correlation function of the XY spin chain is studied at zero temperature. This is called the Emptiness Formation Probability (EFP) and is expressed by the Fredholm determinant in the thermodynamic limit. We formulate the associated Riemann--Hilbert problem and solve it exactly. The EFP is shown to decay in Gaussian.

L. L. Goncalves, M. Lopez de Haro, J. Taguena-Martinez

A restricted dynamics, previously introduced in a kinetic model for relaxation phenomena in linear polymer chains, is used to study the dynamic critical exponent of one-dimensional Ising models. Both the alternating isotopic chain and the alternating-bond chain are considered. In contrast with what occurs for the Glauber dynamics, in these two models the dyn

Cecile Naud, Giancarlo Faini, Dominique Mailly

We report on magnetoresistance transport measurements performed on a bipartite tiling of rhombus in the GaAs/GaAlAs system. We observe for the first time large amplitude $h/e$ oscillations in this network as compared to the one measured in square lattices of similar size. These oscillations are the signature of a recently predicted localization phenomenon in

Gary Steigman

An introductory review of the early evolution of the Universe relevant to the primordial synthesis of the light nuclides deuterium, helium-3, helium-4 and lithium-7. The predictions of the element abundances in the "standard", hot, big bang cosmological model (SBBN) are described. After descriptions of the evolution of the primordial abundances from

Matthew Shetrone, Patrick Cote, W. L. W. Sargent

The Keck I telescope has been used to obtain HIRES spectra for red giants belonging to the Draco, Sextans and Ursa Minor dwarf spheroidal (dSph) galaxies. An analysis of these spectra is presented, along with abundance ratios for more than 20 elements. The resulting database of element abundances for 17 stars is the most extensive yet assembled for stars in

Mary M. Crone, Regina E. Schulte-Ladbeck, Ulrich Hopp, Laura Greggio

We present HST/WFPC2 single-star photometry for the blue dwarf galaxy UGCA 290, whose morphology is intermediate between classic iE Blue Compact Dwarfs and blue dwarfs which exhibit no red background sheet of older stars. The color-magnitude diagram of this galaxy in V and I, extending over six magnitudes, is remarkably similar to that of the star-forming re

C. S. Reynolds

After reviewing the basic physics of X-ray reflection in AGN, we present three case studies which illustrate the current state of X-ray reflection studies. For the low-luminosity AGN NGC4258, we find that the iron line is much narrower than is typically found in higher luminosity AGN. We argue that this is evidence for either a truncated cold accretion disk

C. I. Short, P. H. Hauschildt, S. Starrfield, E. Baron

We present a grid of nova models that have an extremely large number of species treated in non-LTE, and apply it to the analysis of an extensive time series of ultraviolet spectroscopic data for Nova Cygni 1992. We use ultraviolet colors to derive the time development of the effective temperature of the expanding atmosphere during the fireball phase and the

Xiaohu Wang, Abraham Loeb

Beamed gamma-ray burst (GRB) sources produce a bow shock in their gaseous environment. The emitted flux from this bow shock may dominate over the direct emission from the jet for lines of sight which are outside the angular radius of the jet emission, theta. The event rate for these lines of sight is increased by a factor of 260*(theta/5_degrees)^{-2}. For t

A. Merloni, A. C. Fabian

Most astrophysical sources powered by accretion onto a black hole, either of stellar mass or supermassive, when observed with hard X-rays show signs of a hot Comptonizing component in the flow, the so-called corona, with observed temperatures and optical depths lying in a narrow range (0.1 < τ< 1 and 1x10^9 K < T < 3x10^9 K). Here we argue that these facts c

Tyler E. Nordgren, J. T. Armstrong, M. E. Germain, R. B. Hindsley

We present mean angular diameters for two cepheid variables, alpha Ursae Minoris and zeta Geminorum, determined with the Navy Prototype Optical Interferometer (NPOI). We present linear radii for these cepheids and two additional cepheids, delta Cephei and eta Aquilae, previously observed at the NPOI. We find the limb-darkened angular diameter of alpha Ursae

J. C. Augereau, A. M. Lagrange, D. Mouillet, F. Menard

The close environment of four old Pre-Main Sequence stars has been observed thanks to the coronagraphic mode of the HST/NICMOS2 camera at lambda=1.6 micron. In the course of this program, the detection of a circumstellar annulus around HD 141569 has already been presented in Augereau et al.(1999b). In this paper, we report the detection of an elliptical stru

L. Schmidtobreick, M. Haas, D. Lemke

Discrete far-infrared (FIR) sources of M31 are identified in the ISO 175um map and characterized via their FIR colours, luminosities and masses. With a mean size of 800pc, they probably represent several clouds in chance projection or giant cloud complexes. The 175um data point provides crucial information in addition to the IRAS 60 and 100um data: At least

E. Ros, J. C. Guirado, J. M. Marcaide, M. A. Perez-Torres

We observed the quadruple gravitationally lensed image of MGJ0414+0534 on 23 November 1997 with a global VLBI array at 8.4 GHz. We report wide-field imaging results of its four components at submilliarcsecond resolution, displaying complex core-like and jet-like extended structures. A simple model combining a singular isothermal ellipsoid to represent the ma

Pedro Viana

A short introduction to structure formation is given, followed by a discussion of the possible characteristics of the initial perturbations assuming a generic inflationary origin. Observational data related to large-scale structure and the cosmic microwave background radiation is then used in an attempt to constrain the characteristics of such perturbations.

Andrew R Liddle

The cosmological model best capable of fitting current observational data features two separate epochs during which the Universe is accelerating. During the earliest stages of the Universe, such acceleration is known as cosmological inflation, believed to explain the global properties of the Universe and the origin of structure. Observations of the present s

Paolo A. Mazzali, Ken&#39;ichi Nomoto, Enrico Cappellaro, Takayoshi Nakamura

The use of Type Ia supernovae as distance indicators relies on the determination of their brightness. This is not constant, but it can be calibrated using an observed relation between the brightness and the properties of the optical light curve (decline rate, width, shape), which indicates that brighter SNe have broader, slower light curves. However, the phy

Anthony Brown

In the context of the luminosity calibration of the nearer stars I discuss the Hipparcos results on distances to nearby OB associations and open clusters. The shortcomings and assumptions in the analyses used to derive these results are pointed out and for the open clusters a comparison is made with results obtained from main sequence fitting. I conclude tha

Shai Kaspi

A 7.5 years spectrophotometric monitoring program of 28 Palomar-Green quasars to determine the size of their broad emission line region (BLR) is reviewed. We find both the continuum and the emission line fluxes of all quasars to vary during this period. Seventeen objects has adequate sampling for reverberation mapping and in all of them we find the Balmer li

Kouichi Hirotani

We investigate whether the parsec-scale jets of quasars 3C 345 and 3C 279 are dominated by a normal (proton-electron) plasma or a pair (electron-positron) plasma. We first present a new method to compute the kinetic luminosity of a conical jet by using the core size observed at a single very long baseline interferometry frequency. The deduced kinetic luminos

H. C. Bhatt

The Galactic distribution of the high-latitude molecular clouds is considered. It is suggested that the majority of these clouds are clustered in two large shells around the two closest OB associations, Per OB3/Cas-Tau and Sco OB2. The most prominent shell of high-latitude clouds is centred around the Per OB3/ Cas-Tau association which is also at the centre

B. Novosyadlyj, R. Durrer, S. Apunevych

The observational data on the large scale structure (LSS) of the Universe are used to determine cosmological parameters within the class of adiabatic inflationary models. We show that a mixed dark matter model with cosmological constant ($Λ$MDM model) and parameters $Ω_m=0.37^{+0.25}_{-0.15}$, $Ω_Λ=0.69^{+0.15}_{-0.20}$, $Ω_ν=0.03^{+0.07}_{-0.03}$, $N_ν=1$,

I. A. G. Snellen, K. -H. Mack, W. Tschager, R. T. Schilizzi

We report on the investigation of a complete sample of young radio-loud AGN at z<0.25, selected using the new comprehensive radio surveys and the optical APM/POSS-I catalog. This new sample will provide a unique opportunity for statistical studies of the early evolution of radio-loud AGN, free of cosmological evolution effects. In particular, their local lum

H. C. Bhatt, Manoj P

Optical linear polarization measurements are presented for about 30 Vega-like stars. These are then compared with the polarization observed for normal field stars. A significant fraction of the Vega-like stars are found to show polarization much in excess of that expected to be due to interstellar matter along the line of sight to the star. The excess polari

F. Primas, M. Asplund, P. E. Nissen, V. Hill

We report on a new spectroscopic analysis of the very metal deficient star G 64-12 ([Fe/H]=-3.3), aimed at determining, for the first time, its Be content. The spectra were observed during the Science Verification of UVES, the ESO VLT Ultraviolet and Visible Echelle Spectrograph. The high resolution (~48,000) and high S/N (~130 per pixel) achieved at the wav

A. Baykal, M. Stark, J. Swank

Using X-ray data from the Rossi X-Ray Timing Explorer (RXTE), we carried out pulse timing analysis of the transient X-ray pulsar SAX J2103.5+4545. An outburst was detected by All Sky Monitor (ASM) October 25 1999 and reached a peak X-ray brightness of 27 mCrab October 28. Between November 19 and December 27, the RXTE/PCA carried out pointed observations whic

A. Baykal, T. Strohmayer, J. Swank, A. Alpar

We analysed the RXTE archival data of 1E 1048.1-5937 covering a time span of more than one year. The spin down rate of this source decreases by 30 percent during the observation. We could not resolve the X-ray flux variations because of contamination by Eta Carinae. We find that the level of pulse frequency fluctuations of 1E 1048.1-5937 is consistent with t

M. E. Everett, M. E. Huber, S. B. Howell

We discuss the first results from the Faint Sky Variability Survey (Groot et al. 2000). The data consist of V-band light curves, BVI colours, astrometry, and morphology information on several hundred thousand point and extended sources in the magnitude range V=17-25. We discuss the first 30 survey fields covering an area of 8.4 square degrees towards moderat

P. J. Groot, P. M. Vreeswijk, M. E. Everett, S. B. Howell

The Faint Sky Variability Survey is aimed at finding variable objects in the brightness range between 17th and 25th magnitude on timescales between tens of minutes and years with photometric precisions ranging from 3 millimagnitudes for the brightest to 0.2 magnitudes for the faintest objects. An area of at least 50 square degrees, located at mid-galactic la

G. Parmentier, E. Jehin, P. Magain, A. Noels

Based on a model of globular cluster self-enrichment published in a previous paper, we present an explanation for the metallicity gradient observed throughout the galactic Old Halo. Our self-enrichment model is based on the ability of globular cluster progenitor clouds to retain the ejecta of a first generation of Type II Supernovae. The key point is that th

Keith A. Olive

The current status of big bang nucleosynthesis is summarized. Particular attention is paid to recent observations of He4 and Li7 and their systematic uncertainties. Be and B are also discussed in connection to recent Li7 observations and the primordial Li7 abundance.

V. P. Reshetnikov, N. Ya. Sotnikova

We review recent results on the tidal structures of spiral galaxies. Topics included are general characteristics of tails; kinematics of tidal structures and dark haloes of host galaxies; frequency of tidal distortions at z~1.

Raymundo Baptista

The eclipse mapping method is an inversion technique that makes use of the information contained in eclipse light curves to probe the structure, the spectrum and the time evolution of accretion discs. In this review I present the basics of the method and discuss its different implementations. I summarize the most important results obtained to date and discus

Jacco Th. van Loon

The DENIS/ISOGAL near/mid-IR survey of the Milky Way for the first time probes stellar populations in the innermost obscured regions of our galaxy. Ages, metallicities and extinction-corrected luminosities are derived for these stars individually by isochrone fitting to the preliminary IR photometry. A few hundred AGB stars with thick circumstellar dust enve

Josep Marti, I. Felix Mirabel, Sylvain Chaty, Luis F. Rodriguez

We report the results of our search for the near infrared counterpart of the microquasar 1E 1740.7-2942 using the VLT (Based on observations collected at the European Southern Observatory, Chile (ESO No 63.H-0261)). For the first time, several counterpart candidates have been found in our Ks-band images that may be consistent with the best radio and X-ray po

Jens Schmalzing, Masahiro Takada, Toshifumi Futamase

We investigate the non-Gaussian signatures in Cosmic Microwave Background (CMB) maps induced by the intervening large-scale structure through weak lensing. In order to measure the deviation from the Gaussian behavior of the intrinsic temperature anisotropies, we use a family of three morphological descriptors, the so-called Minkowski functionals. We show ana

Pushan Majumdar, Dong-Shin Shin

Recently Anishetty, Majumdar and Sharatchandra have proposed a way of characterizing topologically non-trivial configurations for 2+1 dimensional Yang-Mills theory in a local and manifestly gauge invariant manner. In this paper paper we develop criteria to locate such objects in lattice gauge theory and find them in numerical simulations.

Biao Wu, Qian Niu

The superfluidity of Bose-Einstein condensates in optical lattices are investigated. Apart from the usual Landau instability which occurs when a BEC flows faster than the speed of sound, the BEC can also suffer a dynamical instability, resulting in period doubling and other sorts of symmetry breaking of the system. Such an instability may play a crucial role

P. Kroupa, S. J. Aarseth, J. Hurley

(shortened) Direct N-body calculations are presented of the formation of Galactic clusters using GasEx, which is a variant of the code Nbody6. The calculations focus on the possible evolution of the Orion Nebula Cluster (ONC) by assuming that the embedded OB stars explosively drove out 2/3 of its mass in the form of gas about 0.4 Myr ago. A bound cluster for

G. Degrassi, P. Gambino, G. F. Giudice

We discuss possible large contributions to B -> X_s gamma, which can occur at the next-to-leading order in supersymmetric models. They can originate from terms enhanced by tan(beta) factors, when the ratio between the two Higgs vacuum expectation values is large, or by logarithm of M_{susy}/M_W, when the supersymmetric particles are considerably heavier than

S. A. Vitkalov, Hairong Zheng, K. M. Mertes, M. P. Sarachik

For a broad range of electron densities $n$ and temperatures $T$, the in-plane magnetoconductivity of the two-dimensional system of electrons in silicon MOSFET&#39;s can be scaled onto a universal curve with a single parameter $H_σ(n,T)$, where $H_σ$ obeys the empirical relation $H_σ=A (n) [Δ(n)^2 +T^2]^{1/2}$. The characteristic energy $k_B Δ$ associated wi

Patrik Recher, Eugene V. Sukhorukov, Daniel Loss

We propose and analyze a spin-entangler for electrons based on an s-wave superconductor coupled to two quantum dots each of which is tunnel-coupled to normal Fermi leads. We show that in the presence of a voltage bias and in the Coulomb blockade regime two correlated electrons provided by the Andreev process can coherently tunnel from the superconductor via

S. Nussinov, R. Shrock

We suggest the study of events in the SuperKamiokande neutrino data due to charged- and neutral-current neutrino reactions followed by weak and/or electromagnetic decays of struck nuclei and fragments thereof. This study could improve the prospects of obtaining evidence for $τ$ production from $ν_μ\to ν_τ$ oscillations and could augment the data sample used

Egor Babaev

In this brief report we consider a non-local Abelian Higgs model in the presence of a neutralizing uniform background charge. We show that such a system possesses vortices which key feature is a strong radial electric field. We estimate the basic properties of such an object and characteristic length scales in this model.

R. S. Bhalerao, R. K. Bhaduri

Considering the low-temperature ($T$) and high-baryon-number-density ($n_B$) region of the QCD phase diagram, we present a model for the first-order phase transition between the quark-gluon plasma (QGP) and the recently proposed colour superconducting phase. We study nucleation of a droplet of the superconducting phase within the metastable QGP gas. Numerica

T. Opatrny, G. Kurizki

We propose dissociation of cold diatomic molecules as a source of atom pairs with highly correlated (entangled) positions and momenta, approximating the original quantum state introduced by Einstein, Podolsky and Rosen (EPR) [Phys. Rev. 47, 777 (1935)]. Wavepacket teleportation is shown to be achievable by its collision with one of the EPR correlated atoms a

Richard J. Szabo

The microscopic spectral correlators of the Dirac operator in three-dimensional Yang-Mills theory coupled to fundamental fermions and with three or more colours are derived from the supersymmetric formulation of partially quenched effective Lagrangians. The flavour supersymmetry breaking patterns are appropriately identified and used to calculate the corresp

F. T. Brandt, Ashok Das, J. Frenkel

We extend the Coleman-Hill analysis to non-Abelian Chern-Simons theories containing a tree level topological mass term. We show, in the case of a pure Yang-Mills-Chern-Simons theory, that there are no corrections to the coefficient of the Chern-Simons term beyond one loop in the axial gauge. Our arguments use constraints coming only from small gauge Ward ide

J. I. Collar, Y. Giomataris

The MICROMEGAS detector concept, generally optimized for use in accelerator experiments, displays a peculiar combination of features that can be advantageous in several astroparticle and neutrino physics applications. Their sub-keV ionization energy threshold, excellent energy and space resolution, and a simplicity of design that allows the use of radioclean

Farhad Ardalan, Neda Sadooghi

Anomalies arising from nonplanar triangle diagrams of noncommutative gauge theory are studied. Local chiral gauge anomalies for both noncommutative U(1) and U(N) gauge theories with adjoint matter fields are shown to vanish. For noncommutative QED with fundamental matters, due to UV/IR mixing a finite anomaly emerges from the nonplanar contributions. It invo

G. L. Cardoso, B. de Wit, J. Käppeli, T. Mohaupt

We analyze a broad class of stationary solutions with residual N=1 supersymmetry of four-dimensional N=2 supergravity theories with terms quadratic in the Weyl tensor. These terms are encoded in a holomorphic function, which determines the most relevant part of the action and which plays a central role in our analysis. The solutions include extremal black ho

Matthias R. Gaberdiel, Andrew Neitzke

Some of the consequences that follow from the C_2 condition of Zhu are analysed. In particular it is shown that every conformal field theory satisfying the C_2 condition has only finitely many n-point functions, and this result is used to prove a version of a conjecture of Nahm, namely that every representation of such a conformal field theory is quasiration

J. M. Martinez Resco, M. A. Valle Basagoiti

The color conductivity is computed at leading logarithmic order using a Kubo formula. We show how to sum an infinite series of planar ladder diagrams, assuming some approximations based on the dominance of soft scattering processes between hard particles in the plasma. The result agrees with the one obtained previously from a kinetical approach.

Alfredo T. Suzuki, Alexandre G. M. Schmidt

The only calculations performed beyond one-loop level in the light-cone gauge make use of the Mandelstam-Leibbrandt (ML) prescription in order to circumvent the notorious gauge dependent poles. Recently we have shown that in the context of negative dimensional integration method (NDIM) such prescription can be altogether abandoned, at least in one-loop order

A. Garcia, R. Huerta, G. Sanchez-Colon

We consider the most favorable conditions to indirectly observe the mixing of ordinary and mirror hadrons in non-leptonic and weak radiative decays of hyperons. This allows us to set a lower bound on the masses of mirror baryons. This bound turns out to be impressively high, of the order of $10^6$GeV.

Murat Boratav, Alan A. Watson

We briefly review the status of cosmic ray studies between $10^{14}$ eV and the highest observed energies, namely a few times $10^{20}$ eV. Because of the rather low incident fluxes in this energy range, the studies mostly rely on ground based, large aperture detectors reconstructing the cosmic ray&#39;s properties through the detection of the air-showers th

F. Boniver, P. Mathonet

The elaboration of new quantization methods has recently developed the interest in the study of subalgebras of the Lie algebra of polynomial vector fields over a Euclidean space. In this framework, these subalgebras define maximal equivariance conditions that one can impose on a linear bijection between observables that are polynomial in the momenta and diff

Douglas J. Buettner, P. D. Morley, Ivan Schmidt

We investigate extra spatial dimensions ($D = 3+ε$) in the early universe using very high resolution molecular rotational spectroscopic data derived from a large molecular cloud containing moderately cold carbon monoxide gas at Z $\approx 6.42$. It turns out that the $ε$-dependent quantum mechanical wavelength transitions are solvable for a linear molecule a

Nobuo Sasaki

We investigate the equilibration and the equation of state of a hot hadron gas at finite baryon density using an event generator which is designed to approximately satisfy detailed balance at finite temperatures and finite baryon densities of the hadronic scale (80 MeV < T < 170 MeV and 0.157 fm^-3 < n_B < 0.315 fm^-3). Molecular-dynamical simulations were p

Holger Frahm, Martin Stahlsmeier

We construct a family of electronic ladder models with SO(5) symmetry which have exact ground states in the form of finitely correlated wave functions. Extensions for these models preserving this symmetry are studied using these states in a variational approach. Within this approach, the zero temperature phase diagram of these electronic ladders at half fill

Mohab Abou-Zeid, Harald Dorn

An equation for the quantum average of the gauge invariant Wilson loop in non-commutative Yang-Mills theory with gauge group U(N) is obtained. In the &#39;t Hooft limit, the equation reduces to the loop equation of ordinary Yang-Mills theory. At finite $N$, the equation involves the quantum averages of the additional gauge invariant observables of the non-co

Thomas Vojta, Rastko Sknepnek

We investigate the quantum phase transition of itinerant electrons from a paramagnet to a state which displays long-period helical structures due to a Dzyaloshinskii instability of the ferromagnetic state. In particular, we study how the self-generated effective long-range interaction recently identified in itinerant quantum ferromagnets is cut-off by the he

Satya N. Majumdar, Alan J. Bray

We show that the probability, P_0(l), that the height of a fluctuating (d+1)-dimensional interface in its steady state stays above its initial value up to a distance l, along any linear cut in the d-dimensional space, decays as P_0(l) \sim l^(-θ). Here θis a `spatial&#39; persistence exponent, and takes different values, θ_s or θ_0, depending on how the poin

Evgeny Sorkin, Tsvi Piran

We investigate the effects of pair creation on the internal geometry of a black hole, which forms during the gravitational collapse of a charged massless scalar field. Classically, strong central Schwarzschild-like singularity forms, and a null, weak, mass-inflation singularity arises along the Cauchy horizon, in such a collapse. We consider here the dischar

Michael Forger, Hartmann Römer

A new Poisson bracket for Hamiltonian forms on the full multisymplectic phase space is defined. At least for forms of degree n-1, where n is the dimension of space-time, Jacobi&#39;s identity is fulfilled.

D. W. Berry, H. M. Wiseman

We derive the optimal N-photon two-mode input state for obtaining an estimate ϕof the phase difference between two arms of an interferometer. For an optimal measurement [B. C. Sanders and G. J. Milburn, Phys. Rev. Lett. 75, 2944 (1995)], it yields a variance (Δϕ)^2 \simeq π^2/N^2, compared to O(N^{-1}) or O(N^{-1/2}) for states considered by previous authors

Joshua N. Winn, Jacqueline N. Hewitt, Alok R. Patnaik, Paul L. Schechter

We report the discovery of a new double-image gravitational lens resulting from our search for lenses in the southern sky. Radio source PMN J2004-1349 is composed of two compact components separated by 1.13 arcseconds in VLA, MERLIN and VLBA images. The components have a flux ratio of 1:1 at radio frequencies ranging from 5 GHz to 22 GHz. The I-band optical

A. L. Xavier

A semiclassical formula for the coherent-state propagator requires the determination of specific classical paths inhabiting a complex phase-space through a Hamiltonian flux. Such trajectories are constrained to special boundary conditions which render their determination difficult by common methods. In this paper we present a new method based on Runge-Kutta

P. H. Souto Ribeiro, S. Padua, C. H. Monken

We show that the first experiment with double-slits and twin photons detected in coincidence can be understood as a quantum eraser. The ``which path&#39;&#39; information is erased by transverse indistinguishability obtained by means of mode filtering in the twin conjugated beam. A delayed choice quantum eraser based on the same scheme is proposed.

M. Genovese, C. Novero

We discuss the possibility of synchronising two atomic clocks exchanging entangled photon pairs through a quantum channel. A proposal for implementing practically such a scheme is discussed.

R. F. Werner, M. M. Wolf

We discuss the entanglement properties of bipartite states with Gaussian Wigner functions. Separability and the positivity of the partial transpose are characterized in terms of the covariance matrix of the state, and it is shown that for systems composed of a single oscillator for Alice and an arbitrary number for Bob, positivity of the partial transpose im

Seth Lloyd, Jeffrey H. Shapiro, N. C. Wong

Two particles that are entangled with respect to continuous variables such as position and momentum exhibit a variety of nonclassical features. First, measurement of one particle projects the other particle into the state that is the complex conjugate of the state of the first particle, i.e., measurement of one particle projects the other particle into the t