January 2003 arXiv papers — page 11

Robert A. Wickham, An-Chang Shi, Zhen-Gang Wang

The nucleation of a droplet of stable cylinder phase from a metastable lamellar phase is examined within the single-mode approximation to the Brazovskii model for diblock copolymer melts. By employing a variational ansatz for the droplet interfacial profile, an analytic expression for the interfacial free-energy of an interface of arbitrary orientation betwe

S. Ostanin, V. Trubitsin, J. B. Staunton, S. Y. Savrasov

The stability of high-pressure phases of P has been studied using density functional theory and the local density approximation. Using a linear response technique, we have calculated the phonon spectrum and electron-phonon interaction for bcc P and predict it to be superconducting with $T_c$ of 19 K. We propose that this phase might be realized in epitaxial

A. Liebsch

Photoemission spectra of the perovskites Ca$_x$Sr$_{1-x}$VO$_3$, Ca$_x$La$_{1-x}$VO$_3$, and SrRuO$_3$ indicate that Coulomb correlations are more pronounced at the surface than in the bulk. To investigate this effect we use the dynamical mean field theory combined with the Quantum Monte Carlo technique and evaluate the multi-orbital self-energy. These syste

G. Sierra, J. M. Roman, J. Dukelsky

We summarize previous works on the exact ground state and the elementary excitations of the exactly solvable BCS model in the canonical ensemble. The BCS model is solved by Richardson equations, and, in the large coupling limit, by Gaudin equations. The relationship between this two kinds of solutions are used to classiffy the excitations.

Jurij Smakov, Kenji Harada, Naoki Kawashima

An efficient Quantum Monte Carlo algorithm for the simulation of bosonic systems on a lattice in a grand canonical ensemble is proposed. It is based on the mapping of bosonic models to the spin models in the limit of the infinite total spin quantum number. It is demonstrated, how this limit may be taken explicitly in the algorithm, eliminating the systematic

Y. Furukawa, K. Aizawa, K. Kumagai, R. Ullu

Measurements of proton NMR and the spin lattice relaxation rate 1/T1 in the octanuclear iron (III) cluster [Fe8(N3C6H15)6O2(OH)12][Br8 9H2O], in short Fe8, have been performed at 1.5 K in a powder sample aligned along the main anisotropy z axis, as a function of a transverse magnetic field (i.e., perpendicular to the main easy axis z). A big enhancement of 1

P. Lemmens, G. Guntherodt, C. Gros

An overview of one- and two-dimensional quantum spin systems based on transition-metal oxides and halides of current interest is given, such as spin-Peierls, spin-dimer, geometrically frustrated and ladder systems. The most significant and outstanding contributions of magnetic light scattering to the understanding of these materials are discussed and compare

S. D. Ganichev, I. N. Yassievich, W. Prettl

Experimental and theoretical work on the ionization of deep impurity centers in the alternating terahertz field of high-intensity far-infrared laser radiation, with photon energies tens of times lower than the impurity ionization energy, is reviewed. It is shown that impurity ionization is due to phonon-assisted tunneling which proceeds at high electric fiel

Jacopo Bellazzini, Giulia Menconi, Guido Buresti, Paolo Grigolini

We study the vortex dynamics in an evolutive flow. We carry out the statistical analysis of the resulting time series by means of the joint use of a compression and an entropy diffusion method. This approach to complexity makes it possible for us to establish that the time series emerging from the wavelet analysis of the vortex dynamics is a weakly chaotic p

Yves Lansac, Prabal K. Maiti, Matthew A. Glaser

The translocation of a macromolecule through a nanometer-sized pore is an interesting process with important applications in the development of biosensors for single--molecule analysis and in drug delivery and gene therapy. We have carried out a molecular dynamics simulation study of electrophoretic translocation of a charged polymer through an artificial na

Jairo Sinova, T. Jungwirth, J. Kucera, A. H. MacDonald

We present a theoretical study of the infrared magneto-optical properties of ferromagnetic (III,Mn)V semiconductors. Our analysis combines the kinetic exchange model for (III,Mn)V ferromagnetism with Kubo linear response theory and Born approximation estimates for the effect of disorder on the valence band quasiparticles. We predict a prominent feature in th

R. N. Gurzhi, A. N. Kalinenko, A. I. Kopeliovich, A. V. Yanovsky

We propose a ``spin-guide'' source for generation of electric currents with a high degree of spin polarization, allowing long-distance transmission of the spin-polarization. In the spin-guide scheme proposed here, a non-magnetic conducting channel is wrapped by a magnetic shell which preferentially transmits electrons with a particular spin polarizat

Peter B. Lee, Mark B. Wise, Vineer Bhansali

First passage models, where corporate assets undergo a random walk and default occurs if the assets fall below a threshold, provide an attractive framework for modeling the default process. Recently such models have been generalized to allow a fluctuating default threshold or equivalently a fluctuating total recovery fraction $R$. For a given company a parti

F. P. Mancini, P. Sodano, A. Trombettoni

We study the phase diagram at finite temperature of Josephson junction arrays with capacitive disorder (i.e., random offset charges and/or random charging energies): in the limit of large particle numbers per junction, this is a remarkable physical realization of the disordered boson Hubbard model. By using a mean-field approximation, we compute the average

N. B. Kopnin, V. M. Vinokur

We find that multiple Andreev reflections mediating the transport in superconducting point contacts are strongly affected by a small amount of impurities in the area of the contact. We also argue that the model based on Zener transitions within independent conducting channels is not suitable for kinetic processes in multichannel contacts.

Judith G. Cohen, Norbert Christlieb, Y. -Z. Qian, G. J. Wasserburg

Abundances for 27 elements in the very metal poor dwarf star HE2148-1247 are presented, including many of the neutron capture elements. We establish that HE2148-1247 is a very highly s-process enhanced star with anomalously high Eu as well, Eu/H about half Solar, demonstrating the large addition of heavy nuclei at [Fe/H] = -2.3 dex. Ba and La are enhanced by

Michael D. Gregg, Bradford P. Holden, Michael J. West

The galaxies NGC 4911 and 4921 in the Coma cluster provide spectacular examples of luminous, grand design spirals passing through the hot intracluster medium of a rich cluster of galaxies. Chandra ACIS-I imaging of their environment, coupled with CFHT, HST/WFPC2, and VLA radio imaging, reveal the interactions between the hot X-ray gas and the ISM of the spir

Michael D. Gregg, Michael J. Drinkwater, Michael J. Hilker, Steven Phillipps

We have discovered a new type of galaxy in the Fornax Cluster: ``ultra-compact'' dwarfs (UCDs). The UCDs are unresolved in ground-based imaging and have spectra typical of old stellar systems. Although the UCDs resemble overgrown globular clusters, based on VLT UVES echelle spectroscopy, they appear to be dynamically distinct systems with higher inte

Markos Georganopoulos, Demosthenes Kazanas

We review the broad band properties of X-ray detected hotspots in radio galaxies and quasars. We show that their collective properties can be unified in a framework involving frequency dependent relativistic beaming and varying orientations to the observer's line of sight. The simplest dynamic model consistent with this picture is a slowing-down relativi

Pasquale Temi, William G. Mathews, Fabrizio Brighenti, Jesse D. Bregman

We present far-IR ISO observations of three early-type galaxies in the Virgo cluster. The data were recorded using the ISOPHOT instrument in both the P32 oversampled maps and the P39/37 sparse maps. The maps reach the limiting sensitivity of the ISOPHOT instrument at 60, 90, and 180$μ$m. Two of the most prominent elliptical galaxies in Virgo -- NGC 4472 and

F. Martins, D. Schaerer, M. Heydari-Malayeri

We present the first results of a spectroscopic study of young massive stars in the SMC High Excitation Blob N81. These stars have Mv values which are ~ 2 mag smaller than those of nor mal dwarf stars. Their UV STIS spectra reveal features typical of O stars, but surprisingly weak wind components. The preliminary modelling of these spectr a with the code CMF

I. V. Moskalenko, A. W. Strong, J. F. Ormes, S. G. Mashnik

Recent measurements of the cosmic ray (CR) antiproton flux have been shown to challenge existing CR propagation models. It was shown that the reacceleration models designed to match secondary to primary nuclei ratios (e.g., B/C) produce too few antiprotons. In the present paper we discuss one possibility to overcome these difficulties. Using the measured ant

Jean A. Eilek

Clusters of galaxies are the largest self-gravitating structures in the universe. Each cluster is filled with a large-scale plasma atmosphere, in which primordial matter is mixed with matter that has been processed inside stars. This is a wonderful plasma physics laboratory. Our diagnostics are the data we obtain from X-ray and radio telescopes. The thermal

S. Mieske, M. Hilker, L. Infante

The potential of the Surface Brightness Fluctuation (SBF) method to determine distances to dwarf ellipticals in nearby clusters is investigated. We find that for the Fornax cluster, the SBF method yields reliable results down to very faint magnitudes, in our case down to M_V ~- 11 mag when observing for about 1 hour at good seeing with an 8m-class telescope

James M. De Buizer

The results of a survey searching for outflows using near-infrared imaging is presented. Targets were chosen from a compiled list of massive young stellar objects (YSOs) associated with methanol masers in linear distributions. Presently, it is a widely held belief that these methanol masers are found in (and delineate) circumstellar accretion disks around ma

H. Ritter, U. Kolb

The catalogue lists coordinates, apparent magnitudes, orbital parameters, and stellar parameters of the components and other characteristc properties of 472 cataclysmic binaries, 71 low-mass X-ray binaries and 113 related objects with known or suspected orbital periods together with a comprehensive selection of the relevant recent literature. In addition the

G. Stasinska, Y. Izotov

We consider 400 H II galaxies in which the oxygen abundances were obtained by electron temperature based methods. We split the sample in three metallicity bins. In each bin, a narrow sequence is found not only in pure emission line ratio diagrams but also in terms of Hbeta equivalent width, indicating the existence of an evolutionary sequence. Our diagrams s

Gary J. Hill, Steve Rawlings

The TexOx-1000 (TOOT) radio source redshift survey is designed to find and study typical radio-loud active galaxies to high redshift. They are typical in the same sense that L* galaxies are typical of galaxies in the optical. Previous surveys have only included the most luminous, rare objects at and beyond the peak of activity at z~2, but in going a factor o

Miroslaw Kozlowski, Janina Marciak-Kozlowska

In the paper the Planck, Yukawa and Bohr forces were defined and calculated. It was shown that the Planck force mediates the universe acceleration. The Yukawa and Bohr forces describe the gradients of attractive strong and Coulomb forces. It was shown that smallest, of the present day, value of Planck force in comparison to values of the Yukawa and Bohr forc

Andrea Biviano, Marisa Girardi

We analyze the internal dynamics of 43 non-interacting clusters which are selected from the 2dF Galaxy Redshift Survey 100k public release. We join together the 43 clusters into an ensemble cluster by appropriately scaling their galaxy velocities and clustercentric distances. We solve the Jeans equation for the hydrostatic equilibrium for the member galaxies

S. Esposito, G. Mangano, G. Miele, I. Picardi

We review the purely leptonic neutrino emission processes, contributing to the energy loss rate of the stellar plasma. We perform a complete analysis up to the first order in the electromagnetic coupling constant. In particular the radiative electromagnetic corrections, at order $α$, to the process $e^+ e^- -> ν\barν$ at finite density and temperature have b

HEGRA-Collaboration, F. Aharonian

The HEGRA system of imaging air Cherenkov telescopes has been used to observe the BL Lac object H1426+428 ($z=0.129$) for 217.5 hours in 2002. In this data set alone, the source is detected at a confidence level of $5.3~σ$, confirming this object as a TeV source. The overall flux level during the observations in 2002 is found to be a factor of $\approx 2.5$

S. Corbel, M. A. Nowak, R. P. Fender, A. K. Tzioumis

We present the results of a long-term study of the black hole candidate GX 339-4 using simultaneous radio (from the Australia Telescope Compact Array) and X-ray (from the Rossi X-ray Timing Explorer and BeppoSAX) observations performed between 1997 and 2000. We find strong evidence for a correlation between these two emission regimes that extends over more t

Pascal Borde, Guy Perrin, Thanh Nguyen, Anne Amy-Klein

Wavefront cleaning by single-mode fibers has proved to be efficient in optical-infrared interferometry to improve calibration quality. For instance, the FLUOR instrument has demonstrated the capability of fluoride glass single-mode fibers in this respect in the K and L bands. New interferometric instruments developped for the mid-infrared require the same ca

Pascal Borde, Vincent Coude du Foresto, Gilles Chagnon, Guy Perrin

The calibration process of long baseline stellar interferometers requires the use of reference stars with accurately determined angular diameters. We present a catalog of 374 carefully chosen stars among the all-sky network of infrared sources provided by Cohen et al. 1999. The catalog benefits from a very good sky coverage and a median formal error on the a

A. -C. Donea, R. J. Protheroe

Motivated by unification schemes of active galactic nuclei, we review evidence for the existence of a small-scale dust torus in M87, a Fanaroff-Riley Class I radio galaxy. Since there is no direct evidence of any thermal emission from its torus we consider indirect evidence, such as BLR activity and ageing arguments to model the cold dust structure of M87. I

R. J. Protheroe

I re-examine the brightness temperature problem in PKS 0405-385 which is an extreme intra-day variable radio quasar with an inferred brightness temperature of $\sim 5 \times 10^{14}$ K at 5 GHz, well above the Compton catastrophe limit of $\sim 10^{11}$ K reached when the synchrotron photon energy density exceeds the energy density of the magnetic field. If

P. Borde, A. Leger, D. Rouan, A. C. Cameron

For the Eddington mission, the intrinsic stellar variability can be a major source of noise in the detection of extrasolar planets by the transit method. We derive that most detections of terrestrial planets (1-2 R_Earth) will occur around G or K stars with 15-16th magnitude. When these stars are 7-12 times more variable than the Sun on a 10 hour timescale,

Mitsuhiko Honda, Hirokazu Kataza, Yoshiko K. Okamoto, Takashi Miyata

We have carried out mid-infrared N-band spectroscopic observations of the T Tauri star Hen 3-600A in the TW Hydra association with the COMICS on the 8.2m Subaru Telescope and found structured features in its spectrum. These structured features are well explained by a combination of crystalline forsterite, crystalline enstatite, silica and glassy olivine grai

Weidong Li, Alexei V. Filippenko, Ryan Chornock, Edo Berger

We present photometric and spectroscopic observations of supernova (SN) 2002cx, which reveal it to be unique among all observed type Ia supernovae (SNe Ia). SN 2002cx exhibits a SN 1991T-like premaximum spectrum, a SN 1991bg-like luminosity, and expansion velocities roughly half those of normal SNe Ia. Photometrically, SN 2002cx has a broad peak in the $R$ b

Kaspar von Braun

We report on the discovery and analysis of short-period (0.1 days $< P <$ 5 days), photometrically varying binary stars around and below the main-sequence turnoff of the globular clusters (GCs) NGC 3201, M10, & M12. These eclipsing binaries (EBs) may be used to determine directly the distances to GCs and constrain the Population II stellar main-sequence mass

Andrew I. MacFadyen

Winds blown from accretion disks formed inside massive rotating stars may result in stellar explosions observable as Type Ibc and Type II supernovae. A key feature of the winds is their ability to produce the radioactive Nickel-56 necessary to power a supernova light curve. The wind strength depends on accretion disk cooling by neutrino emission and photo-di

Diego F. Torres, Gustavo E. Romero, Thomas M. Dame, Jorge A. Combi

It might be thought that supernova remnants (SNRs) more distant than a few kiloparsec from Earth could not have been detected by the EGRET experiment. This work analyzes the observational status of this statement in the light of new CO studies of SNRs.

D. A. Frail, S. A. Yost, E. Berger, F. A. Harrison

We present radio observations of the afterglow of the bright gamma-ray burst GRB980703 made between one day and one year after the burst. These data are combined with published late-time radio measurements and existing optical, near-infrared (NIR) and X-ray observations to create a comprehensive broadband dataset for modeling the physical parameters of the o

V. S. Ptuskin, I. V. Moskalenko, F. C. Jones, A. W. Strong

In a recent paper (Moskalenko et al., 2002), it has been shown that the flux of secondary cosmic ray (CR) antiprotons appears to be contradictory to measurements of secondary to primary nuclei ratios in cosmic rays when calculated in the same Galactic propagation model. The contradiction appears as a value of the diffusion coefficient necessary to match the

Takenori Fujii, Ichiro Terasaki

A parent insulator of the Bi-based high-$T_c$ superconductor Bi$_2$Sr$_{2-x}$La$_x$CaCu$_2$O$_{8+δ}$ was successfully grown by a traveling solvent floating zone method. The in-plane resistivity $ρ_{ab}$ shows metallic behavior ($dρ_{ab}/dT >$ 0) near room temperature, although the magnitude of the resistivity is far above the Mott limit for metallic conducti

Katrin Becker, Melanie Becker, Keshav Dasgupta, Paul S. Green

We study new compactifications of the SO(32) heterotic string theory on compact complex non-Kahler manifolds. These manifolds have many interesting features like fewer moduli, torsional constraints, vanishing Euler character and vanishing first Chern class, which make the four-dimensional theory phenomenologically attractive. We take a particular compact exa

C. M. Newman, D. L. Stein

In this topical review we discuss the nature of the low-temperature phase in both infinite-ranged and short-ranged spin glasses. We analyze the meaning of pure states in spin glasses, and distinguish between physical, or ``observable&#39;&#39;, states and (probably) unphysical, ``invisible&#39;&#39; states. We review replica symmetry breaking, and describe w

Yong-Zhong Qian

There has been significant progress in the understanding of the r-process over the last ten years. The conditions required for this process have been examined in terms of the parameters for adiabatic expansion from high temperature and density. There have been many developments regarding core-collapse supernova and neutron star merger models of the r-process

Matthew R. Francis, Arthur Kosowsky

This paper was withdrawn by the authors because it has been supplanted by gr-qc/0311007 and gr-qc/0311038.

D. Yu. Grigoriev, E. Jankowski, F. V. Tkachov

In a simulated measurement of the $W$-boson mass, evaluation of Fisher&#39;s information shows the optimal jet definition to be physically equivalent to the $k_\mathrm{T}$ algorithm while being much faster at large multiplicities.

S. Maxson

The unitary Clifford algebras are described here for the first time, and arise from the intersection of the orthogonal and common symplectic (Weyl) Clifford algebras of the complexification of the canonical phase space. The convergence of the exponential map is possible in available topologies in our constructions, but it does not converge without additional

S. Maxson

In this third of a series of four articles, we continue the study of the representations of the hamiltonian dynamical transformations of systems of correlated quantized oscillators. By our use of generalized wave function solutions to Schr{ö}dinger&#39;s equation (belonging to a rigged Hilbert space), and by considering the algebra of observables as a whole,

S. Maxson

In this second in a series of four articles we create a mathematical formalism sufficient to represent nontrivial hamiltonian quantum dynamics, including resonances. Some parts of this construction are also mathematically necessary. The specific construction is the transforming of a pair of quantized free oscillators into a resonant system of coupled oscilla

S. Maxson

In this first of a series of four articles, it is shown how a hamiltonian quantum dynamics can be formulated based on a generalization of classical probability theory using the notion of quasi-invariant measures on the classical phase space for our description of dynamics. This is based on certain distributions rather than invariant Gibbs measures. The first

Rouzbeh Allahverdi, Bhaskar Dutta, Anupam mazumdar

We propose that the observed baryon asymmetry of the Universe can naturally arise from a net asymmetry generated in the sleptonic sector at fairly low reheat temperatures. The best candidate is indeed the right-handed sneutrino. The initial asymmetry in the sneutrino sector can be produced from the decay of the inflaton, and is subsequently transferred into

Michael Feigenson, Lior Klein, James W. Reiner, Malcolm R. Beasley

${\rm SrRuO_3}$ is a 4d itinerant ferromagnet (T$_{c}$ $\sim $150 K) with stripe domain structure. Using high-quality thin films of SrRuO$_{3}$ we study the resistivity induced by its very narrow ($\sim 3$ nm) Bloch domain walls, $ρ_{DW}$ (DWR), at temperatures between 2 K and T$_{c}$ as a function of the angle, $θ$, between the electric current and the ferr

Breno. R. Segatto, Julio S. Azevedo, Manoelito M. de Souza

Motivated by improving the understanding of the quantum-to-classical transition we use a simple model of classical discrete interactions for studying the discrete-to-continuous transition in the classical harmonic oscillator. A parallel is traced with gravity for stressing the relevance of such discrete interaction models.

A. Delgado, M. Redi

Stability of AdS space allows scalar fields to have negative mass squared as long as the Breitenlohner-Freedman bound is satisfied. In a compactification of AdS instead, to avoid instabilities, a tachyonic bulk mass must be supplemented by appropriate brane actions. In this paper we clarify the meaning of the lower bound in the Randall-Sundrum scenario with

Miguel D. Bustamante, Sergio A. Hojman

We present an approach to the construction of action principles for differential equations, and apply it to field theory in order to construct systematically, for integrable equations which are based on a Nijenhuis (or hereditary) operator, a ladder of action principles which is complementary to the well-known multi-Hamiltonian formulation. We work out resul

P. Korbel, W. Wójcik, A. Klejnberg, J. Spalek

We supplement (and critically overview) the existing extensive analysis of antiferromagnetic solution for the Hubbard model with a detailed discussion of two specific features, namely (i) the evolution of the magnetic (Slater) gap (here renormalized by the electronic correlations) into the Mott-Hubbard or atomic gap, and (ii) a rather weak renormalization of

R. Lisboa, M. Malheiro, P. Alberto

We investigate the role of the Coulomb and the vector-isovector $ρ$ potentials in the asymmetry of the neutron and proton pseudospin splittings in nuclei. To this end, we solve the Dirac equation for the nucleons using central vector and scalar potentials with Woods-Saxon shape and $Z$ and $N-Z$ dependent Coulomb and $ρ$ potentials added to the vector potent

M. Toller

Motivated by ultra-high-energy cosmic ray physics, we discuss all the possible alternatives to the familiar Lorentz transformations of the momentum and the energy of a particle. Starting from natural physical requirements, we exclude all the possibilities, apart from the ones which arise from the usual four-vector transformations by means of a change of coor

D. Toublan, J. B. Kogut

We use the Nambu--Jona-Lasinio model to study the effects of the isospin chemical potential on the QCD phase diagram at nonzero temperature and baryon chemical potential. We find that the phase diagram is qualitatively altered by a small isospin chemical potential. There are two first order phase transitions that end in two critical endpoints, and there are

Petr O. Fedichev, Uwe R. Fischer, Alessio Recati

We investigate vortex-antivortex pair creation in a supersonically expanding and contracting quasi-2D Bose-Einstein condensate at zero temperature. For sufficiently large amplitude condensate oscillations, pair production provides the leading dissipation mechanism. The condensate oscillations decay in a nonexponential fashion, and the dissipation rate depend

Oleg Yevtushenko, Vladimir Kravtsov

Energy level statistics of Hermitian random matrices $\hat H$ with Gaussian independent random entries $H_{i\geq j}$ is studied for a generic ensemble of almost diagonal random matrices with $ <|H_{ii}|^{2} > \sim 1$ and $<|H_{i\neq j}|^{2} >= b {\cal F}(|i-j|) \ll 1$. We perform a regular expansion of the spectral form-factor $K(τ) = 1 + b K_{1}(τ) + b^{2}

I. Garcia-Mata, M. Saraceno, M. E. Spina

We study the asymptotic long-time behavior of open quantum maps and relate the decays to the eigenvalues of a coarse-grained superoperator. In specific ranges of coarse graining, and for chaotic maps, these decay rates are given by the Ruelle-Pollicott resonances of the classical map.

Thomas Klose

We compute the anomalous dimensions of BMN operators with two covariant derivative impurities at the planar level up to first order in the effective coupling lambda&#39;. The result equals those for two scalar impurities as well as for mixed scalar and vector impurities given in the literature. Though the results are the same, the computation is very differe

Janusz Grabowski

Axioms of Lie algebroid are discussed in order to review some known aspects for non-experts. In particular, it is shown that a Lie QD-algebroid (i.e. a Lie algebra bracket on the Functions(M)-module F of sections of a vector bundle E over a manifold M which satisfies [X,fY]=f[X,Y]+A(X,f)Y for all X,Y from F, all f from Functions(M), and for certain A(X,f) fr

CLAS Collaboration, K. Joo, L. C. Smith

The polarized longitudinal-transverse structure function $σ_{LT^\prime}$ has been measured in the $Δ(1232)$ resonance region at $Q^2=0.40$ and 0.65 GeV$^2$. Data for the $p(\vec e,e&#39;p)π^o$ reaction were taken at Jefferson Lab with the CEBAF Large Acceptance Spectrometer (CLAS) using longitudinally polarized electrons at an energy of 1.515 GeV. For the fi

Jean-Marc Gerard, Christopher Smith

Search for patterns in the numerous B-decay modes now available is necessary in order to test the Cabibbo-Kobayashi-Maskawa theory of CP-violation. In particular, the well-structured pattern of B to PI K branching ratios may lead to a quantized spectrum for direct CP-asymmetries, providing in this way a rather unique opportunity to discriminate between stron

Elias C. Vagenas

We treat the two-dimensional Achucarro-Ortiz black hole (also known as (1+1) dilatonic black hole) as a Casimir-type system. The stress tensor of a massless scalar field satisfying Dirichlet boundary conditions on two one-dimensional &#34;walls&#34; (&#34;Dirichlet walls&#34;) is explicitly calculated in three different vacua. Without employing known regular

Vitor Cardoso, Jose&#39; P. S. Lemos

We present an exact expression for the quasinormal modes of scalar, electromagnetic and gravitational perturbations of a near extremal Scwarzschild-de Sitter black hole and we show why a previous approximation holds exactly in this near extremal regime. In particular, our results give the asymptotic behavior of the quasinormal frequencies for highly damped m

H. H. Wen, Z. Y. Liu, Z. A. Xu, Z. Y. Weng

Nernst effect has been measured for an underdoped and an optimally doped $La_{2-x}Sr_xCuO_4$ single crystal with the magnetic field applied along different directions. For both samples, when $H \|$ c, a significant Nernst voltage appears above $T_c$ and keeps measurable up to a high temperature (100 K) as reported by Xu et al.[ Nature 406, 486(2000) ]. Howev

Roman O. Popovych, Vyacheslav M. Boyko, Maryna O. Nesterenko, Maxim W. Lutfullin

Using a new powerful technique based on the notion of megaideal, we construct a complete set of inequivalent realizations of real Lie algebras of dimension no greater than four in vector fields on a space of an arbitrary (finite) number of variables. Our classification amends and essentially generalizes earlier works on the subject. Known results on classifi

Volker Bromm, Abraham Loeb

We review recent theoretical results on the formation of the first stars and quasars in the universe, and emphasize related open questions. In particular, we list important differences between the star formation process at high redshifts and in the present-day universe. We address the importance of heavy elements in bringing about the transition from an earl

K. Pozgajcic, C. Gros

We study the ionic Hubbard model at temperature T=0 within the mean-field approximation, and show that the charge gap does not close completely at the ionic-band insulator to antiferromagnetic insulator transition, contrary to previous expectations. Furthermore, we find an intermediate phase for on-site repulsions $U>U_c$ for different lattices, and calculat

R. Bonciani, P. Mastrolia, E. Remiddi

We carry out a systematic investigation of all the 2-loop integrals occurring in the electron vertex in QED in the continuous $D$-dimensional regularization scheme, for on-shell electrons, momentum transfer $t=-Q^2$ and finite squared electron mass $m_e^2=a$. We identify all the Master Integrals (MI&#39;s) of the problem and write the differential equations

F. Darabi

We study a $(4+D)$-dimensional Kaluza-Klein cosmology with a Robertson-Walker type metric having two scale factors $a$ and $R$, corresponding to $D$-dimensional internal space and 4-dimensional universe, respectively. By introducing an exotic matter as the space-time part of the higher dimensional energy-momentum tensor, a 4-dimensional decaying cosmological

Yoshiko Kanada-En&#39;yo, Hisashi Horiuchi

The structures of the ground and excited states of 12Be were studied with antisymmetrized molecular dynamics. The ground state was found to be a state with a developed 2-alpha core with two neutrons occupying the intruder orbits. The energy levels of the newly measured spin-assigned states were described well, except for the $1^-_1$ state. The calculations i

L. T. Buchman, J. M. Bardeen

The tetrad-based equations for vacuum gravity published by Estabrook, Robinson, and Wahlquist are simplified and adapted for numerical relativity. We show that the evolution equations as partial differential equations for the Ricci rotation coefficients constitute a rather simple first-order symmetrizable hyperbolic system, not only for the Nester gauge cond

Sung Ho Wang

Let $ l : Σ\to X$ be a weakly Lagrangian map of a compact orientable surface $ Σ$ in a Kähler surface $ X$ which is area minimizing in its homotopy class of maps in $ W^{1,2}(Σ, X)$, the Sobolev space of maps of square integrable first derivative. Schoen and Wolfson showed such $ l$ is Lipschitz, and it is smooth except at most at finitely many points of Mas

Igor V. Igumenshchev, Ramesh Narayan, Marek A. Abramowicz

We present three-dimensional MHD simulations of rotating radiatively inefficient accretion flows onto black holes. In the simulations, we continuously inject magnetized matter into the computational domain near the outer boundary, and we run the calculations long enough for the resulting accretion flow to reach a quasi-steady state. We have studied two limit

H. Moya-Cessa, M. Fernandez-Guasti

We study the time evolution for the quantum harmonic oscillator subjected to a sudden change of frequency. It is based on an approximate analytic solution to the time dependent Ermakov equation for a step function. This approach allows for a continuous treatment that differs from former studies that involve the matching of two time independent solutions at t

Boris F. Samsonov, A. A. Suzko

Using an isomorphism between Hilbert spaces $L^2$ and $\ell^{2}$ we consider Hamiltonians which have tridiagonal matrix representations (Jacobi matrices) in a discrete basis and an eigenvalue problem is reduced to solving a three term difference equation. Technique of intertwining operators is applied to creating new families of exactly solvable Jacobi matri

Aram W. Harrow, Michael A. Nielsen

We define several quantitative measures of the robustness of a quantum gate against noise. Exact analytic expressions for the robustness against depolarizing noise are obtained for all unitary quantum gates, and it is found that the controlled-not is the most robust two-qubit quantum gate, in the sense that it is the quantum gate which can tolerate the most

J. S. Kole

Three numerical algorithms are proposed to solve the time-dependent elastodynamic equations in elastic solids. All algorithms are based on approximating the solution of the equations, which can be written as a matrix exponential. By approximating the matrix exponential with a product formula, an unconditionally stable algorithm is derived that conserves the

Mark H. Milman, Slava G. Turyshev

The Space Interferometry Mission (SIM) is a space-based long-baseline optical interferometer for precision astrometry. One of the primary objectives of the SIM instrument is to accurately determine the directions to a grid of stars, together with their proper motions and parallaxes, improving a priori knowledge by nearly three orders of magnitude. The basic

R. Bijker

Three-body clusters are studied in the algebraic cluster model. Particular attention is paid to the case of three identical particles. It is shown in a geometrical analysis that the harmonic oscillator, the deformed oscillator and the oblate symmetric top are contained as special solutions. An application of the oblate top limit to the nucleus 12C suggests t

C. D. Roberts

Dynamical chiral symmetry breaking is a nonperturbative phenomenon that may be studied using QCD&#39;s gap equation. Model-independent results can be obtained with a nonperturbative and symmetry preserving truncation. The gap equation yields the massive dressed-quark propagator, which has a spectral representation when considered as a function of the current

A. P. Severyukhin, V. V. Voronov, Ch. Stoyanov, Nguyen Van Giai

A finite rank separable approximation for the quasiparticle RPA calculations with Skyrme interactions that was proposed in our previous work is extended to take into account the coupling between one- and two-phonon terms in the wave functions of excited states. It is shown that characteristics calculated within the suggested approach are in a good agreement

P. Chau Huu-Tai, A. Frank, N. A. Smirnova, P. Van Isacker

It is argued that spectral features of quantal systems with random interactions can be given a geometric interpretation. This conjecture is investigated in the context of two simple models: a system of randomly interacting d bosons and one of randomly interacting fermions in a j=7/2 shell. In both examples the probability for a given state to become the grou

F. H. Al-Khudair, G. L. Long

The low-energy level structure and electromagnetic transitions of $^{48,50}$Cr nuclei have been studied by using interacting boson model with isospin (IBM-3). A sequence of isospin excitation bands with isospin $(T= T_{z}$, $T_{z}+1$ and $ T_{z}+2) $ has been assigned, and compared with available data. According to this study, the $2^{+}_{3} $ and $2^{+}_{2}

Martin J. Savage

I review the current status of the application of effective field theory to nuclear physics, and its present implications for nuclear astrophysics.

R. Neubecker, E. Benkler, R. Martin, G. -L. Oppo

Defects play an important role in a number of fields dealing with ordered structures. They are often described in terms of their topology, mutual interaction and their statistical characteristics. We demonstrate theoretically and experimentally the possibility of an active manipulation and removal of defects. We focus on the spontaneous formation of two-dime

Dragomir Neshev, Elena Ostrovskaya, Yuri Kivshar, Wieslaw Krolikowski

We study experimentally nonlinear localization effects in optically-induced gratings created by interfering plane waves in a photorefractive crystal. We demonstrate the generation of spatial bright solitons similar to those observed in arrays of coupled optical waveguides. We also create pairs of out-of-phase solitons which resemble ``twisted&#39;&#39; local

Nils Dencker, Johannes Sjoestrand, Maciej Zworski

The purpose of this note is to show how some results from the theory of partial differential equations apply to the study of pseudo-spectra of non-self-adjoint operators, which is a topic of current interest in applied mathematics.

Igor Rivin

We define a class of multivariate Laurent polynomials closely related to Chebyshev polynomials, and prove the simple but somewhat surprising (in view of the fact that the signs of the coefficients of the Chebyshev polynomials themselves alternate) result that their coefficients are non-negative. We further show that a Central Limit Theorem holds for our poly

Kristin Lauter

The purpose of this note is to suggest an analogue for genus 2 curves of part of Gross and Zagier&#39;s work on elliptic curves. Experimentally, for genus 2 curves with CM by a quartic CM field K, it appears that primes dividing the denominators of the discriminants of the Igusa class polynomials all have the property 1) that they are bounded by d, the absol

Aobing Li, YanYan Li

We establish a general Liouville type theorem for conformally invariant fully nonlinear equations.