July 1999 arXiv papers — page 4

Yutaka Sakamura, Yasuo Hemmi, Hiroaki Matsuo, Hiroshi Sakai

A conceptual design work and a basic experimental study of a new beam profile monitor have been performed. The monitor will be used to measure emittance of an electron beam in the ATF damping ring at KEK, in which the transverse beam size of about 10 micron is expected. It utilizes a CW laser and an optical cavity, instead of a material wire, to minimize int

CDF Collaboration, T. Affolder

The oscillation frequency Delta-md of B0 anti-B0 mixing is measured using the partially reconstructed semileptonic decay anti-B0 -> l- nubar D*+ X. The data sample was collected with the CDF detector at the Fermilab Tevatron collider during 1992 - 1995 by triggering on the existence of two lepton candidates in an event, and corresponds to about 110 pb-1 of p

T. W. Baumgarte, S. A. Hughes, L. Rezzolla, S. L. Shapiro

We report on our numerical implementation of fully relativistic hydrodynamics coupled to Einstein's field equations in three spatial dimensions. We briefly review several steps in our code development, including our recasting of Einstein's equations and several tests which demonstrate its advantages for numerical integrations. We outline our implemen

J. A. Valiente-Kroon

A discussion of polyhomogeneity (asymptotic expansions in terms of $1/r$ and $\ln r$) for zero-rest-mass fields and gravity and its relation with the Newman-Penrose (NP) constants is given. It is shown that for spin-$s$ zero-rest-mass fields propagating on Minkowski spacetime, the logarithmic terms in the asymptotic expansion appear naturally if the field do

S. Yazadjiev

It's shown that the rotating dilaton-axion black hole solution can be obtained from GGHS static charged dilaton black hole solution via Newman-Janis method.

H. X. Tang, F. G. Monzon, Ron Lifshitz, M. C. Cross

We explore electrically injected, spin polarized transport in a ballistic two-dimensional electron gas. We augment the Buettiker-Landauer picture with a simple, but realistic model for spin-selective contacts to describe multimode reservoir-to-reservoir transport of ballistic spin 1/2 particles. Clear and unambiguous signatures of spin transport are establis

F. C. Montenegro, D. P. Belanger, Z. Slanic, J. A. Fernandez-Baca

The highly diluted antiferromagnet Mn(0.35)Zn(0.65)F2 has been investigated by neutron scattering in zero field. The Bragg peaks observed below the Neel temperature TN (approximately 10.9 K) indicate stable antiferromagnetic long-range ordering at low temperature. The critical behavior is governed by random-exchange Ising model critical exponents (nu approxi

S. Tsonchev, R. D. Coalson

Lattice-field calculations are performed on a Gaussian polymer chain confined to move within the region defined by two fused spheres. The results of the calculations are in accord with recent experimental measurements and computer simulations, and suggest that current theoretical understanding of polymer partitioning phenomena is not adequate when excluded v

A. A. Schmidt, J. J. Rodríguez-Núñez

We derive the superconductiong mean-field equations for an attractive interaction, V, in the s-wave channel when local Coulomb interactions are taken into account for any value of U. Our results show that the Coulomb repulsion is detrimental to the critical temperature, $T_c$, and the order parameter, $Δ(T)$, for values of $U \geq |V|$. Furthermore, our resu

S. N. Dorogovtsev, J. F. F. Mendes

We present an exact description of a crossover between two different regimes of simple analogies of small-world networks. Each of the sites chosen with a probability $p$ from $n$ sites of an ordered system defined on a circle is connected to all other sites selected in such a way. Every link is of a unit length. Thus, while $p$ changes from 0 to 1, an averag

Thomas C. Halsey, Deniz Ertas

We study the static equilibrium of an elastic sphere held in a rigid groove by gravity and frictional contacts, as determined by contact mechanics. As a function of the opening angle of the groove and the tilt of the groove with respect to the vertical, we identify two regimes of static equilibrium for the ball. In the first of these, at large opening angle

I. I. Mazin, D. A. Papaconstantopoulos, D. J. Singh

Accurate orthogonal tight-binding Hamiltonians are constructed for ferromagnetic SrRuO$_3$ and the layered perovskite superconductor, Sr$_2$RuO$_4$ by fitting to all-electron full-potential local density band structures obtained by the linearized augmented planewave method. These Hamiltonians allow the band structure to be computed on very fine meshes in the

E. Akkermans, K. Mallick

In these notes we discuss the topological nature of some problems in condensed matter physics. We adopt the language of differential geometry to present this subject and our aim is to develop some intuition towards concepts like curvature, fiber bundles, connexions, characteristic classes and topological invariants. The lectures end with a theoretical analys

G. L. Buchbinder, V. N. Shapov

In this work we first study the quantum diffusion in a volume of a crystalline solid at high interstitial concentrations when the effects of the short-range interactions between the diffusing particles are to be factors. Within the scope of the small-polaron formalism the transition rate depending on both the temperature and the interstitial concentration ha

Youngho Park

We compare the spectra of the new $π$ operator of the SO(5) theory and the conventional $Δ$ operator for the two-dimensional t-J model. We also calculate the weight transferred to the two-hole ground state from half-filling by these operators. We find that the spectra of these operators are quite similar and the weight for the $π$ operator is smaller than th

Konstantin Kladko, Jiri Malek, Alan R. Bishop

We report a theoretical analysis of intrinsic localized modes in a quasi-one-dimensional charge-transfer-solid $[Pt(en)_2][Pt(en)_2 Cl_2](ClO_4)_4$(PtCl). We discuss strongly nonlinear features of resonant Raman overtone scattering measurements on PtCl, arising from quantum intrinsic localized (multiphonon) modes (ILMs) and ILM-plus-phonon states. We show, t

T. Prellberg, A. L. Owczarek

In earlier work we provided the first evidence that the collapse, or coil-globule, transition of an isolated polymer in solution can be seen in a four-dimensional model. Here we investigate, via Monte Carlo simulations, the canonical lattice model of polymer collapse, namely interacting self-avoiding walks, to show that it not only has a distinct collapse tr

A. L. Owczarek, T. Prellberg

The coil-globule transition of an isolated polymer has been well established to be a second-order phase transition described by a standard tricritical O(0) field theory. We provide compelling evidence from Monte Carlo simulations in four dimensions, where mean-field theory should apply, that the approach to this (tri)critical point is dominated by the build-

K. Malarz, A. Z. Maksymowicz

In this work a simple solid-on-solid (SOS) model of inhomogeneous films epitaxial growth is presented. The results of the computer simulations based on the random deposition (RD) enriched by a local relaxation which tends to maximize the number of a particle-particle lateral bonds (PPLB) against barriers blocking diffusion are presented. The influence of str

K. Malarz, A. Z. Maksymowicz

In this paper we present a generalization of a simple solid-on-solid epitaxial model of thin films growth, when surface morphology anisotropy is provoked by anisotropy in model control parameters: binding energy and/or diffusion barrier. The anisotropy is discussed in terms of the height-height correlation function. It was experimentally confirmed that the d

K. Malarz, A. Z. Maksymowicz

The random deposition model must be enriched to reflect the variety of surface roughness due to some material characteristics of the film growing by vacuum deposition or sputtering. The essence of the computer simulation in this case is to account for possible surface migration of atoms just after the deposition, in connection with binding energy between ato

Takahiro Hatano

Jarzynski equality [Phys. Rev. E {\bf 56}, 5018 (1997)] is found to be valid with slight modefication for the transitions between nonequilibrium stationary states, as well as the one between equilibrium states. Also numerical results confirm its validity. Its relevance for nonequilibrium thermodynamics of the operational formalism is discussed.

Stacy S. McGaugh

Two hypothesized solutions of the mass discrepancy problem are cold dark matter (CDM) and modified Newtonian dynamics (MOND). The virtues and vices of these very different hypotheses are largely disjoint, making the process of distinguishing between them very dependent on how we weigh disparate lines of evidence. One clear difference is the nature of the pri

Milan M. Cirkovic

All gasdynamical models for the evolution of gaseous content of galaxies assume that cooling from the hot, virialized phase to the cold phase occured through some sort of thermal instability. Subsequent formation of colder clouds embedded in the hot, rarefied medium is a well-known process appearing in many astrophysical circumstances and environments. The c

Noam Soker, Amos Harpaz

We examine the envelope properties of asymptotic giant branch (AGB) stars as they evolve on the upper AGB and during the early post-AGB phase. Due to the high mass loss rate, the envelope mass decreases by more than an order of magnitude. This makes the density profile below the photosphere much shallower, and the entropy profile much steeper. We discuss the

Ravi Sankrit, Kenneth R. Sembach, Claude R. Canizares

The Faint Object Spectrograph on the Hubble Space Telescope was used to obtain spectra of the central region of M87. These spectra cover the wavelength range 1140 - 1606 Angstrom and have a resolution of about 1 Angstrom. The nuclear continuum is clearly visible in the spectra. The only strong line that is observed is Ly-alpha, which has a velocity width of

L. M. Lubin, R. J. Brunner

We present the first results of our application of photometric redshifts to the study of galaxy populations in high-redshift clusters. For this survey, we are examining a sample of galaxy clusters at z > 0.6 which have already been well-studied in the optical and infrared wavelengths (Oke, Postman & Lubin 1998). Our main goal is to use photometric redshifts

Robert J. Brunner, Andrew J. Connolly, Alex S. Szalay

Measuring the evolution in the clustering of galaxies over a large redshift range is a challenging problem. For a two-dimensional galaxy catalog, however, we can measure the galaxy-galaxy angular correlation function which provides information on the density distribution of galaxies. By utilizing photometric redshifts, we can measure the angular correlation

Tristan Guillot

Interior models of Jupiter and Saturn are calculated and compared in the framework of the three-layer assumption, which rely on the perception that both planets consist of three globally homogeneous regions: a dense core, a metallic hydrogen envelope, and a molecular hydrogen envelope. Within this framework, constraints on the core mass and abundance of heav

Michael M. Shara, Allan Sandage, David R. Zurek

Data obtained in the 1950-1955 Palomar campaign for the discovery of classical novae in M81 are set out in detail. Positions and apparent B magnitudes are listed for the 23 novae that were found. There is modest evidence that the spatial distribution of the novae does not track the B brightness distribution of either the total light or the light beyond an is

R. Michael Rich, Michael Shara, S. Michael Fall, David Zurek

We report new photometry of populous intermediate-age clusters in the SMC using the {\sl Hubble Space Telescope}. In contrast to the accepted picture, these clusters appear to have formed in two brief intervals, one $8\pm 2$ Gyr ago, and a more recent burst $2\pm 0.5$ Gyr ago. When the ridgelines of the four clusters (NGC 339, 361, 416, and Kron 3) in the 8

A. S. Evans, D. -C. Kim, J. M. Mazzarella, N. Z. Scoville

Millimeter CO(1-0) interferometry and high resolution, Hubble Space Telescope (HST) 1.1, 1.6, and 2.2 micron imaging of the radio compact galaxy PKS 1345+12 are presented. With an infrared luminosity of 2x10^{12} L_sun, PKS 1345+12 is a prime candidate for studying the link between the ultraluminous infrared galaxy phenomenon and radio galaxies. These new ob

U. Fritze-v. Alvensleben, U. Lindner, C. S. Möller

We describe the evolution of galaxies in a chemically consistent way accounting for the increasing initial metallicity of successive generations of stars. The enrichment of various types of model galaxies is compared with Damped Ly$α$ (= DLA) abundances over the redshift range from ${\rm z \sim 0}$ through ${\rm z > 4.4}$. We discuss properties and compositi

N. Dinshaw, A. S. Evans, H. Epps, N. Z. Scoville

High resolution, 1.1, 1.6, and 2.2 micron imaging of the luminous infrared galaxy NGC 6090 obtained with NICMOS of the Hubble Space Telescope are presented. These new observations are centered on the two nuclei of the merger, and reveal the spiral structure of the eastern galaxy and the amorphous nature of the western galaxy. The nuclear separation of 3.2 kp

A. Rosenberg, I. Saviane, G. Piotto, A. Aparicio

Based on a new large, homogeneous photometric database of 35 Galactic globular clusters (GGCs), a set of distance and reddening independent relative age indicators has been measured. The observed D(V-I)_2.5 and D(V)(HB-TO) vs. metallicity relations have been compared with the relations predicted by two recent updated libraries of isochrones. Using these mode

M. Kutschera

A model of the ferromagnetic origin of magnetic fields of neutron stars is considered. In this model, the magnetic phase transition occurs inside the core of neutron stars soon after formation. However, owing to the high electrical conductivity the core magnetic field is initially fully screened. We study how this magnetic field emerges for an outside observ

Tsvi Piran

For a few seconds a gamma-ray burst (GRB) becomes the brightest object in the Universe, over-shining the rest of the Universe combined! Clearly this reflects extreme conditions that are fascinating and worth exploring. The recent discovery of GRB afterglow have demonstrated that we are on the right track towards the resolution of this long standing puzzle. T

Reynier F. Peletier, Alexandre Vazdekis, Santiago Arribas, Carlos del Burgo

Integral field spectroscopy has been obtained for the nuclear regions of 3 large, well-studied, early-type galaxies. From these spectra we have obtained line strength maps for about 20 absorption lines, mostly belonging to the Lick system. An extensive comparison with multi-lenslet spectroscopy shows that accurate kinematic maps can be obtained, and also rep

U. Fritze-v. Alvensleben

Any stellar system with a star formation history (SFH) more extended than a massive star's lifetime will be composite in metallicity. Our method of chemically consistent evolutionary synthesis tries to account for the increasing initial metallicity of successive generations of stars. Using various sets of input physics for a range of metallicities $10^{-

Ara Ioannisian, Apostolos Pilaftsis

In Kaluza-Klein theories of low-scale quantum gravity, gravitons and isosinglet neutrinos may propagate in a higher-dimensional space with large compact dimensions, whereas all particles of the Standard Model are confined on a (1+3)-dimensional subspace. After compactification of the extra dimensions, the resulting Yukawa couplings of the Kaluza-Klein neutri

Z. H. Wang, H. C. Lee

We derive an expression with four adjustable parameters that reproduces well the 20x20 Miyazawa-Jernigan potential matrix extracted from known protein structures. The numerical values of the parameters can be approximately computed from the surface tension of water, water-screened dipole interactions between residues and water and among residues, and average

F. Garcia, O Rodriguez, F. Guzman, H. Dias

Microscopic Combinatorial approach is used to calculate the state and level densities with fixed exciton numbers, in some actinide nuclei. Deformed Saxon-Woods shell model was used as a basis from which all posible configurations were generated. The pairing interaction was taken into account by applying the BCS theory to each configurations. Both the spin an

Jeremy Michelson, Andrew Strominger

N-particle quantum mechanics described by a sigma model with an N-dimensional target space with torsion is considered. It is shown that an SL(2,R) conformal symmetry exists if and only if the geometry admits a homothetic Killing vector $D^a$ whose associated one-form $D_a$ is closed. Further, the SL(2,R) can always be extended to Osp(1|2) superconformal symm

T. K. Kuo, Sadek W. Mansour, Guo-Hong Wu

The hierarchical structure in the quark masses and mixings allows its ten physical parameters to be most conveniently encoded in mass matrices of the upper triangular form. We classify these matrices in the hierarchical, minimal parameter basis where the mismatch between the weak and mass eigenstates involves only small mixing angles. Ten such pairs are obta

Michael P. McCooey

If a (possibly finite) compact Lie group acts effectively, locally linearly, and homologically trivially on a closed, simply-connected four-manifold with second Betti number at least three, then it must be isomorphic to a subgroup of S^1 x S^1, and the action must have nonempty fixed-point set. Our results strengthen and complement recent work by Edmonds, Ha

M. Cvetic, H. Lu, C. N. Pope, K. S. Stelle

We derive a component-field expansion of the Green-Schwarz action for the type IIA string, in an arbitrary background of massless NS-NS and R-R bosonic fields, up to quadratic order in the fermionic coordinates θ. Using this action, we extend the usual derivation of Buscher T-duality rules to include not only NS-NS, but also R-R fields. Our implementation of

Alex Buchel, Gary Shiu, S. -H. Henry Tye

We consider anomaly cancelations in Type IIB orientifolds on T^4/Z_N with quantized NS-NS sector background B-flux. For a rank b B-flux on T^4 (b is always even) and when N is even, the cancelation requires a 2^{b/2} multiplicity of states in the 59-open string sector. We identify the twisted sector R-R scalars and tensor multiplets which are involved in the

S. B. Giddings, S. F. Ross

We use the AdS/CFT duality to study the special point on the Coulomb branch of ${\cal N}=4$ SU(N) gauge theory which corresponds to a spherically symmetric shell of D3-branes. This point is of interest both because the spacetime region inside the shell is flat, and because this configuration gives a very simple example of the transition between D-branes in t

R. N. Mohapatra, S. Nandi, A. Pérez-Lorenzana

We discuss the profile of neutrino masses and mixings in models with large extra dimensions when right handed neutrinos are present in the branes along with the usual standard model particles. In these models, string scale must be bigger than $10^{8}$ GeV to have desired properties for the neutrinos at low energies. The lightest neutrino mass is zero and the

L. F. Canto, B. V. Carlson, M. S. Hussein, A. F. R. de Toledo Piza

We discuss the origin of the difference between the harmonic value of the width of the multiphonon giant resonances and the smaller observed value. Analytical expressions are derived for both the effective width and the average cross-section. The contribution of the Brink-Axel mechanism in resolving the discrepancy is pointed out.

Yutaka Hosotani, Jefferson Bjoraker

Regular monopole and dyon solutions to the SU(2) Einstein Yang-Mills equations in asymptotically anti-de Sitter space are discussed. A class of monopole solutions are shown to be stable against spherically symmetric linear perturbations.

Ivo Sachs

We discuss AdS_{2+1} (BTZ) black holes arising in type 0 string theory corresponding to D1-D5 and F1-NS5 bound states. In particular we describe a new family of non-dilatonic solutions with only Dp_{+}, that is ``electric'' branes. These solutions are distinguished by the absence of fermions in the world volume theory which is an interacting CFT. The

N. Berkovits, M. Bershadsky, T. Hauer, S. Zhukov

We quantize the superstring on the AdS_2 x S^2 background with Ramond-Ramond flux using a PSU(1,1|2)/U(1) x U(1) sigma model with a WZ term. One-loop conformal invariance of the model is guaranteed by a general mechanism which holds for coset spaces G/H where G is Ricci-flat and H is the invariant locus of a Z_4 automorphism of G. This mechanism gives confor

Patrick Bruno

This paper presents a review of the phenomenon of interlayer exchange coupling in magnetic multilayers. The emphasis is put on a pedagogical presentation of the mechanism of the phenomenon, which has been successfully explained in terms of a spin-dependent quantum confinement effect. The theoretical predictions are discussed in connection with corresponding

Igor Frenkel, Naihuan Jing, Weiqiang Wang

We establish a $q$-analog of our recent work on vertex representations and the McKay correspondence. For each finite group $Γ$ we construct a Fock space and associated vertex operators in terms of wreath products of $Γ\times \mathbb C^{\times}$ and the symmetric groups. An important special case is obtained when $Γ$ is a finite subgroup of $SU_2$, where our

Eduard Schmidt, Ludwig Knoell, Dirk-Gunnar Welsch

The quantum statistics of damped higher-order optical solitons are analyzed numerically, using cumulant-expansion techniques in Gaussian approximation. A detailed analysis of nonclassical properties in both the time and the frequency domain is given, with special emphasis on the role of absorption. Highly nonclassical broadband spectral correlation is predic

Bojan Bistrovic, Dubravko Klabucar

The presently experimentally interesting form factor for the anomalous process gamma -> pi^+ pi^0 pi^- is calculated as the quark "box"-amplitude where the intermediate fermion loop is the one of constituent quarks with the pseudoscalar coupling to pions. This also corresponds to the form factor, in the lowest order in pion interactions, of the sigma

V. I. Yukalov, S. Gluzman

The self-similar analysis of time series is generalized by introducing the notion of scenario probabilities. This makes it possible to give a complete statistical description for the forecast spectrum by defining the average forecast as a weighted fixed point and by calculating the corresponding a priori standard deviation and variance coefficient. Several e

I. D. Karachentsev, D. I. Makarov, W. K. Huchtmeier

We consider global HI and optical properties of about three hundred nearby galaxies with V$_0 < 500$ km/s. The majority of them have individual photometric distance estimates. The galaxy sample parameters, e.g. their linear diameters, their HI mass-to-luminosity ratio, their total mass-to-luminosity ratio, their mean optical surface brightness show some know

K. Pinn

I explicitly work out closed form solutions for the optimal hedging strategies (in the sense of Bouchaud and Sornette) in the case of European call options, where the underlying is modeled by (unbiased) iid additive returns with Student-t distributions. The results may serve as illustrative examples for option pricing in the presence of fat tails.

A. Naji, S. Rouhani, A. R. Rastegar

This paper has been withdrawn

A. S. Holevo

In information theory the reliability function and its bounds, describing the exponential behavior of the error probability, are the most important quantitative characteristics of the channel performance. From a general point of view, these bounds provide certain measures of distinguishability of a given set of states. In an earlier paper we introduced quant

M. Laine, M. Shaposhnikov

We define a non-local gauge-invariant Green&#39;s function which can distinguish between the symmetric (confinement) and broken (Higgs) phases of the hot SU(2)xU(1) electroweak theory to all orders in the perturbative expansion. It is related to the coupling of the Chern-Simons number to a massless Abelian gauge field. The result implies either that there is

V. Dzhunushaliev

It is shown that the event horizon of 4D black hole or $ds^2 = 0$ surfaces of multidimensional wormhole-like solutions reduce the amount of information necessary for determining the whole spacetime and hence satisfy the Holography principle. This leads to the fact that by matching two metrics on a $ds^2 = 0$ surface (an event horizon for 4D black holes) we c

V. V. Nesterenko, I. G. Pirozhenko

The Casimir energy of an infinite compact cylinder placed in a uniform unbounded medium is investigated under the continuity condition for the light velocity when crossing the interface. As a characteristic parameter in the problem the ratio $ξ^2=(ε_1-ε_2)^2/ (ε_1+ε_2)^-2 = (μ_1-μ_2)^2/(μ_1+ μ_2)^2 \le 1$ is used, where $ε_1$ and $μ_1$ are, respectively, the

Leor Barack, Amos Ori

We study analytically, via the Newman-Penrose formalism, the late-time decay of linear electromagnetic and gravitational perturbations along the event horizon (EH) of black holes. We first analyze in detail the case of a Schwarzschild black hole. Using a straightforward local analysis near the EH, we show that, generically, the ``ingoing&#39;&#39; ($s>0$) co

P. Markos

Numerical studies of the Anderson transition are based on the finite-size scaling analysis of the smallest positive Lyapunov exponent. We prove numerically that the same scaling holds also for higher Lyapunov exponents. This scaling supports the hypothesis of the one-parameter scaling of the conductance distribution. From the collected numerical data for qua

V. Latora, M. Baranger, A. Rapisarda, C. Tsallis

Under certain conditions, the rate of increase of the statistical entropy of a simple, fully chaotic, conservative system is known to be given by a single number, characteristic of this system, the Kolmogorov-Sinai entropy rate. This connection is here generalized to a simple dissipative system, the logistic map, and especially to the chaos threshold of the

M. C. Bergère

We establish a one-to-one correspondance between the &#39;&#39;composite particles&#39;&#39; with $N$ particles and the Young tableaux with at most $N$ rows. We apply this correspondance to the models of Calogero-Sutherland and Ruijsenaars-Schneider and we obtain a momentum space representation of the &#39;&#39;composite particles&#39;&#39; in terms of creat

Stefanie Komossa, Janek Meerschweinchen

Narrow Line Seyfert 1 (NLSy1) galaxies have recently received a lot of attention due to their unusual optical--X-ray properties which are not yet well understood. Photoionization models of the circum-nuclear emission/absorption regions allow to investigate scenarios to explain the main characteristics of NLSy1s, i.e., (i) extremely steep X-ray spectra within

Osamu Takagi, Tetsuro Saso

Linear conductance through a quantum dot is calculated under a finite magnetic field using the modified perturbation theory. The method is based on the second-order perturbation theory with respect to the Coulomb repulsion, but the self-energy is modified to reproduce the correct atomic limit and to fulfill the Friedel sum rule exactly. Although this method

Hee Il Kim

Recently, it has been shown that the primordial black holes (PBHs) produced by near critical collapse in the expanding universe have a scaling mass relation similar to that of black holes produced in asymptotically flat spacetime. Distinct from PBHs formed with mass about the horizon mass (Type I), the PBHs with the scaling relation (Type II) can be created

Luc Berge, Tristram J. Alexander, Yuri S. Kivshar

A general stability criterion is derived for the D-dimensional ground states of the Gross-Pitaevskii equation, which describes attractive Bose-Einstein condensates confined in a magnetic trap. These ground states are shown to avoid the collapse in finite time and are proven to be stable in two and three spatial dimensions.

Goro Hatayama, Atsuo Kuniba, Taichiro Takagi

We introduce a class of cellular automata associated with crystals of irreducible finite dimensional representations of quantum affine algebras U&#39;_q(\hat{\geh}_n). They have solitons labeled by crystals of the smaller algebra U&#39;_q(\hat{\geh}_{n-1}). We prove stable propagation of one soliton for \hat{\geh}_n = A^{(2)}_{2n-1}, A^{(2)}_{2n}, B^{(1)}_n,

Stephan Roche

Generic quantum interference effects occuring in 1D-quasicrystals are reviewed with emphasis on the joint effect of phason disorder on electronic localization and propagation modes. In close conjunction with properties of real materials, the contributions of quantum interferences in several regimes close to the metal insulator transition are outlined.

Xiang-Bin Wang, C. H. Oh, L. C. Kwek

Fidelity plays a key role in quantum information and communication theory. Fidelity can be interpreted as the probability that a decoded message possesses the same information content as the message prior to coding and transmission. In this paper, we give a formula of Bures fidelity for displaced squeezed thermal states directly by the displacement and squee

J. P. Clemens, P. R. Rice, L. M. Pedrotti

We consider a laser composed of a single atom in a microcavity, with a coherent or incoherent pump. We consider both three- and four-level gain schemes, and examine the output spectrum of such lasers. We find that the linewidth generally scales as the inverse of the photon number. For large atom-field coupling, a vacuum-Rabi doublet structure is obtained. In

Friedrich W. Hehl, Yuri N. Obukhov, Guillermo F. Rubilar

We will display the fundamental structure of classical electrodynamics. Starting from the axioms of (1) electric charge conservation, (2) the existence of a Lorentz force density, and (3) magnetic flux conservation, we will derive Maxwell&#39;s equations. They are expressed in terms of the field strengths $(E,{\cal B})$, the excitations $({\cal D},H)$, and t

Tsung-Hsun Yang, Tsong-Hsin Lim, Jyh-Long Chern, Kenju Otsuka

Chaotic bursts are observed in a single-mode microchip Nd:YVO$_4$ laser with fiber feedback. The physical characteristic of the instability is a random switching between two different dynamical states, i.e., the noise-driven relaxation oscillation and the chaotic spiking oscillation. As the feedback strength varied, transition which features the strong inter

Filip Sain, Hermann Riecke

The dynamics of hexagon patterns in rotating systems are investigated within the framework of modified Swift-Hohenberg equations that can be considered as simple models for rotating convection with broken up-down symmetry, e.g. non-Boussinesq Rayleigh-Benard or Marangoni convection. In the weakly nonlinear regime a linear stability analysis of the hexagons r

J. -U. Nabi, H. V. Klapdor-Kleingrothaus

Allowed weak interaction rates for sd-shell nuclei in stellar environment are calculated using a generalized form of proton-neutron quasiparticle RPA model with separable Gamow-Teller forces. Twelve different weak rates are calculated for each nucleus as a function of temperature and density. This project consists of calculation of weak rates for a total of

Barry Simon

We prove a Feynman-Kac formula for Schrodinger operators with potentials V(x) that obey (for all ε> 0): V(x) \geq - ε|x|^2 - C_ε. Even though e^{-tH} is an unbounded operator, any ϕ, ψ\in L^2 with compact support lie in D(e^{-tH}) and <ϕ, e^{-tH}ψ> is given by a Feynman-Kac formula.

Ronald Fintushel, Ronald J. Stern

It is the purpose of this paper to construct families of examples of nonsymplectic 4-manifolds which (up to sign) have just one Seiberg-Witten basic class.

Ronald Fintushel, Ronald J. Stern

We describe a collection of constructions which illustrate a panoply of ``exotic&#39;&#39; smooth 4-manifolds.

Michael Kleber

We present a set of algebraic relations among Schur functions which are a multi-time generalization of the ``discrete Hirota relations&#39;&#39; known to hold among the Schur functions of rectangular partitions. We prove the relations as an application of a technique for turning Plucker relations into statements about Schur functions and other objects with s

C. Grunspan

Cet artice donne des formules explicites pour des densites d&#39;integrales de mouvement du systeme de sinus-Gordon sur reseau.

Aidan Schofield, Michel Van den Bergh

The representations of dimension vector $α$ of the quiver Q can be parametrised by a vector space $R(Q,α)$ on which an algebraic group $\Gl(α)$ acts so that the set of orbits is bijective with the set of isomorphism classes of representations of the quiver. We describe the semi--invariant polynomial functions on this vector space in terms of the category of

Michael E. Hoffman

Given a locally finite graded set A and a commutative, associative operation on A that adds degrees, we construct a commutative multiplication * on the set of noncommutative polynomials in A which we call a quasi-shuffle product; it can be viewed as a generalization of the shuffle product. The resulting commutative algebra can be given the structure of a Hop

Albert Fannjiang, Tomasz Komorowski

We establish diffusion and fractional Brownian motion approximations for motions in a Markovian Gaussian random field with a nonzero mean.

Sergey Finashin

I construct &#34;fake algebraic curves&#34; in $Cp^2$. More precisely, for any k>2, I construct infinitely many pairwise smoothly non-isotopic (and moreover not ambient diffeomorphic) smooth surfaces $F\subset Cp^2$ homeomorphic to a non-singular algebraic curve of degree 2k, realizing the same homology class as such a curve and having abelian fundamental gr

Igor Rivin

We show that the number of simple closed geodesics of length bounded by L on a hyperbolic surface of genus g with c cusps and b boundary components grows roughly like L^{6g+2b+2c-6}. This has been conjectured for some time.

Julian Barquin

A new approach which generalizes the Selective Modal Analyis (SMA) and algorithms based upon it for solving the generalized eigenvalue problem is described. This approach allows for the systematic consideration of physical properties of the system under study. Two small application cases demonstrate the capabilities of the proposed approach.

Naihuan Jing

We introduce a twisted quantum affine algebra associated to each simply laced finite dimensional simple Lie algebra. This new algebra is a Hopf algebra with a Drinfeld-type comultiplication. We obtain this algebra by considering its vertex representation. The vertex representation quantizes the twisted vertex operators of Lepowsky-Wilson and Frenkel-Lepowsky

Vladimir V. Kisil

We describe a construction of wavelets (coherent states) in Banach spaces generated by ``admissible&#39;&#39; group representations. Our main targets are applications in pure mathematics while connections with quantum mechanics are mentioned. As an example we consider operator valued Segal-Bargmann type spaces and the Weyl functional calculus. Keywords: Wave

R. L. Jaffe, L. R. Williamson

The Casimir energy is the first-order-in-\hbar correction to the energy of a time-independent field configuration in a quantum field theory. We study the Casimir energy in a toy model, where the classical field is replaced by a separable potential. In this model the exact answer is trivial to compute, making it a good place to examine subtleties of the probl

R. de Ritis, A. A. Marino, C. Rubano, P. Scudellaro

We extend the concept of quintessence to a flat nonminimally coupled scalar - tensor theories of gravity. By means of Noether&#39;s symmetries for the cosmological pointlike Lagrangian L, it is possible to exhibit exact solutions for a class of models depending on a free parameter s. This parameter comes out in the relationship existing between the coupling

A. E. Kudryavtsev, B. M. A. G. Piette, W. J. Zakrzewski

We study classical solutions of a particular version of the modified Skyrme model in (3+1) dimensions. The model possesses Skyrmion solutions as well as stable domain walls that connect different vacua of the theory. We show that there is an attractive interaction between Skyrmions and domain walls. Thus Skyrmions can be captured by the domain walls. We show

Igor Nikitin

A theory of closed bosonic string in time-like gauge, related in Lorentz-invariant way with the world sheet, is considered. Absence of quantum anomalies in this theory is shown.

S. A. Bulgadaev

Possible generalizations of the topological (or Berezinskii-Kosterlitz-Thouless) phase transition on multicomponent 2D systems with nontrivial vector homotopic group pi_1 are considered. Relations between Ginzburg-Landau like theories, non-linear sigma-models on maximal Cartan subgroups of simple compact Lie groups and generalized sine-Gordon type theories a

Bihn Zhou, Chuan-Jie Zhu

In this note we present an application of the Schwarzian derivative. By exploiting some properties of the Schwarzian derivative, we solve the equation appearing in the gravity-dilaton-antisymmetric tensor system. We also mention that this method can also be used to solve some other equations.