April 1999 arXiv papers — page 4

S. J. Sanders, A. Szanto de Toledo, C. Beck

A review of the characteristic features found in fully energy-damped, binarydecay yields from light heavy-ion reactions with $20\leq A_{target} + A_{projectile}\leq 80$ is presented. The different aspects of these yields that have been used to support models of compound-nucleus (CN) fission and deep-inelastic dinucleus orbiting are highlighted. Cross section

O. M. Del Cima, D. H. T. Franco, J. A. Helayel-Neto, O. Piguet

A rigorous algebraic proof of the full finiteness in all orders of perturbation theory is given for the Yang-Mills-Chern-Simons theory in a general three-dimensional Riemannian manifold. We show the validity of a trace identity, playing the role of a local form of the Callan-Symanzik equation, in all loop orders, which yields the vanishing of the beta-functi

G. Giachetta, L. Mangiarotti, G. Sardanashvily

In Hamiltonian time-dependent mechanics, the Poisson bracket does not define dynamic equations, that implies the corresponding peculiarities of describing time-dependent holonomic constraints. As in conservative mechanics, one can consider the Poisson bracket of constraints, separate them in first and second class constraints, construct the Koszul-Tate resol

N. Ilieva, W. Thirring

We construct a Hamiltonian which in a scaling limit becomes equivalent to one that can be diagonalized by a Bogoliubov transformation. There may appear simultaneously a mean-field and a superconducting phase. They influence each other in a complicated way. For instance, an attractive mean field may stimulate the superconducting phase and a repulsive one may

Alain Connes, Henri Moscovici

We show by a direct computation that, for any Hopf algebra with a modulus-like character, the formulas first introduced in [CM] in the context of characteristic classes for actions of Hopf algebras, do define a cyclic module. This provides a natural generalization of Lie algebra cohomology to the general framework of Noncommutative Geometry, which covers the

Frank Sottile

We show that the Schubert calculus of enumerative geometry is real, for special Schubert conditions. That is, for any such enumerative problem, there exist real conditions for which all the a priori complex solutions are real.

D. V. Osipov

There exists the Krichever map from the set of quintets (C,p,F,t,e) (where C is an integral and complete algebraic curve, p a smooth rational point, F a rank 2 torsion free coherent sheaf on C, t a local formal parameter in p and e a formal trivialization of F around p) to the infinite Grassmanian of $k((z)) \oplus k((z))$. We describe the images of quintets

A. A. Glutsuk

For a generic deformation of a two-dimensional holomorphic vector field with elementary degenerate singular point (saddle-node) we express the Martinet - Ramis orbital analytic classification invariants of the nonperturbed field in terms of the limit transitions between the linearizing charts of singularities of the perturbed field. In the case, when the mul

Jinqiao Duan, Vincent Ervin

In this article we study the solution of the Kuramoto-Sivashinsky equation (for surface erosion or surface growth) on a bounded interval subject to a random forcing term. We show that a unique solution to the equation exists for all time and depends continuously on the initial data.

Thomas Friedrich

We estimate from below by geometric data the eigenvalues of the periodic Sturm-Liouville operator $- 4 d^2/ds^2 + κ^2 (s)$ with potential given by the curvature of a closed curve.

James Propp

This document is a brief summary of progress that has been made on the problems posed in the document "Twenty Open Problems in Enumeration of Matchings" (also available from this server as math.CO/9801060). NOTE: This article has now been superseded by math.CO/9904150.

James Propp

This document is an exposition of an assortment of open problems arising from the exact enumeration of (perfect) matchings of finite graphs. Roughly half have been solved at the time of this writing; see the document "Twenty Open Problems in Enumeration of Matchings: Progress Report" (also available from this server as math.CO/9801061). NOTE: This ar

Nadav Drukker, David J. Gross, Hirosi Ooguri

The AdS/CFT correspondence suggests that the Wilson loop of the large N gauge theory with N=4 supersymmetry in 4 dimensions is described by a minimal surface in AdS_5 x S^5. We examine various aspects of this proposal, comparing gauge theory expectations with computations of minimal surfaces. There is a distinguished class of loops, which we call BPS loops,

J. L. F. Barbon, A. Pasquinucci

We consider aspects of instanton dynamics in the large-N limit using the AdS/CFT duality for D0/D4 bound states. In the supergravity picture of wrapped D0-brane world-lines on D4-branes, we find the single-instanton measure and discuss its dependence on compactification finite-size effects, as well as its matching to perturbative results. In the non-supersym

C. Ekstrand, J. Mickelsson

In [Carey, A.L., J. Mickelsson, and M. K. Murray: Comm. Math. Phys. 183, 707 (1997)] Schwinger terms in hamiltonian quantization of chiral fermions coupled to vector potentials were computed, using some ideas from the theory of gerbes, with the help of the family index theorem for a manifold with boundary. Here, we generalize this method to include gravitati

Prasanta K. Tripathy

We find static spherically symmetric monopoles in Einstein-Born-Infeld-Higgs model in 3+1 dimensions. The solutions exist only when a parameter $\a $ (related to the strength of Gravitational interaction) does not exceed certain critical value. We also discuss magnetically charged non Abelian black holes in this model. We analyse these solutions numerically.

R. Leitgeb, J. Rant, M. Schweda, H. Zerrouki

We discuss the ultraviolet finiteness of the two-dimensional BF model coupled to topological matter quantized in the axial gauge. This noncovariant gauge fixing avoids the infrared problem in the two-dimensional space-time. The BF model together with the matter coupling is obtained by dimensional reduction of the ordinary three-dimensional BF model. This pro

O. B. Zaslavskii

Found is a general form of static solutions in exactly solvable models of 2d dilaton gravity at finite temperature. We reveal a possibility for the existence of everywhere regular solutions including black holes, semi-infinite throats and star-like configurations. In particular, we consider the Bose-Parker-Peleg (BPP) model which possesses a semi-infinite th

Dirk Prange

We give explicit and inductive formulas for the construction of a Lorentz covariant renormalization in the EG approach. This automatically provides for a covariant BPHZ subtraction at totally spacelike momentum useful for massless theories.

A. Bottino, N. Fornengo

In these lectures we first briefly review the main observational facts which imply that most part of matter in the Universe is not visible and some recent intriguing experimental data which would point to a significant contribution to Omega due to a cosmological constant. We subsequently discuss some particle candidates for dark matter, with particular empha

Alan Kostelecky

A general Lorentz-violating extension of the standard model of particle physics, allowing for both CPT-even and CPT-odd effects, is described. Some of its theoretical aspects and experimental implications are summarized.

M. Braun, V. Vechernin

In the framework of the recently proposed QCD based parton model for the cumulative phenomena in the interactions with nuclei the dependence of the cumulative pion production rates on the transverse momentum is studied. The mean value of the transverse momentum is found to grow with x in the cumulative region. The obtained results are in agreement with the a

G. L. Fogli, E. Lisi, A. Marrone, G. Scioscia

The recent observations of atmospheric nu events from the Super-Kamiokande experiment are compatible with three-flavor neutrino oscillations, occurring dominantly in the nu_mu<--->nu_tau channel and subdominantly in the nu_mu<--->nu_e channel. We present an updated analysis of the three-flavor mass-mixing parameters consistent with the present phenomenology,

J. Kwiecinski, L. Motyka

The contribution of the QCD pomeron to the processes: e+e- to e+e- J/psi J/psi and e+ e- to e+ e- hadrons (with tagged electrons) is discussed. We focus on reactions which occur via photon-photon collisions, with virtual photons coming from the Weizsaecker-Wiliams spectrum of the electrons. We stress the importance of the non-leading corrections to the BFKL

F. L. Villante

The energy spectrum of recoil electrons from solar neutrino scattering, as observed by Superkamiokande, is deformed with respect to that expected from SSM calculations. We considered ν-e scattering from neutrinos produced by the electron-capture on ^{8}B nuclei, e^{-}+^{8}B --> ^{8}Be^{*}+ν_{e}, as a possible explanation of the spectral deformation. A flux Φ

M. Strohmeier-Presicek, T. Gutsche, R. Vinh Mau, Amand Faessler

We investigate the hadronic two-body decay modes of the scalar-isoscalar $f_0(1370)$, $f_0(1500)$ and $f_0(1710)$ states as resulting from the mixture of the lowest lying scalar glueball with the isoscalar states of the ground state $^3P_0$ $Q\bar Q$ nonet. In the decay analysis we take into account the direct coupling of the quarkonia and glueball component

Zoltan Ligeti

Some recent theoretical work on inclusive B decays relevant for the model independent determination of |V_{ub}| and |V_{cb}| is summarized. The theoretical predictions and their reliability for several differential decay distributions in B -> X_{c,u}e nu and B -> X_s gamma are reviewed. These can be used to determine certain important HQET matrix elements. T

PACS Collaboration, S. Aoki, G. Boyd, R. Burkhalter

We present results of a large-scale simulation for the flavor non-singlet light hadron spectrum in quenched lattice QCD with the Wilson quark action. Hadron masses are calculated at four values of lattice spacing in the range $a \approx$ 0.1 - 0.05 fm on lattices with a physical extent of 3 fm at five quark masses corresponding to $m_π/m_ρ\approx 0.75$ - 0.4

Mauricio Bellini

The warm inflation scenario is an alternative mechanism which can explain the isotropic and homogeneous Universe which we are living in. In this work I extend a previously introduced formalism, without the restriction of slow - roll regime. Quantum to classical transition of the fluctuations is studied by means of the &#34;transition function&#34; here intro

Marc Mars

We obtain a characterization of the Kerr metric among stationary, asymptotically flat, vacuum spacetimes, which extends the characterization in terms of the Simon tensor (defined only in the manifold of trajectories) to the whole spacetime. More precisely, we define a three index tensor on any spacetime with a Killing field, which vanishes identically for Ke

S. Mayburov

The quantum space-time model which accounts material Reference Frames (RF) quantum effects considered for flat space-time and ADM canonical gravity. As was shown by Aharonov for RF - free material object its c.m. nonrelativistic motion in vacuum described by Schrodinger wave packet evolution which modify space coordinate operator of test particle in this RF

T. Deguchi, F. H. L. Essler, F. Göhmann, A. Klümper

We review fundamental issues arising in the exact solution of the one-dimensional Hubbard model. We perform a careful analysis of the Lieb-Wu equations, paying particular attention to so-called `string solutions&#39;. Two kinds of string solutions occur: $Λ$ strings, related to spin degrees of freedom and $k-Λ$ strings, describing spinless bound states of el

N. Lemke, I. A. Campbell

We show using extensive simulation results and physical arguments that an Ising system on a two dimensional square lattice, having interactions of random sign between first neighbors and ferromagnetic interactions between second neighbors, presents a phase transition at a non-zero temperature.

N. P. Rapapa, A. J. Bray

The dynamics of phase separation for a binary fluid subjected to a uniform shear are solved exactly for a model in which the order parameter is generalized to an n-component vector and the large-n limit taken. Characteristic length scales in directions parallel and perpendicular to the flow increase as (t^5/\ln t)^{1/4} and (t/\ln t)^{1/4} respectively. The

Arkadiusz Wojs, Izabela Szlufarska, Kyung-Soo Yi, John J. Quinn

Electron-hole systems on a Haldane sphere are studied by exact numerical diagonalization. Low lying states contain one or more types of bound charged excitonic complexes Xk-, interacting through appropriate pseudopotentials. Incompressible ground states of such multi-component plasmas are found. A generalized multi-component Laughlin wavefunction and composi

M. Grueninger, D. van der Marel, A. Damascelli, A. Erb

The optical conductivity sigma (omega) of undoped YBa2Cu3O6 is studied in detail in the mid-infrared range. Substitutions on all but the Ba site are used to identify the prominent absorption processes at 2800 and 3800 cm^-1. Experimental evidence for bimagnon-plus-phonon absorption is collected. A more critical analysis of the lineshape and the spectral weig

Junren Shi, Song He, X. C. Xie

According to the scaling theory of localization, all quantum electronic states are localized in two-dimensional (2D) systems. One consequence of the theory is that there is no quantum percolation transition in 2D. However, in a real system at a finite temperature, electron phase coherent length is finite and the system is between quantum and classical. We fi

David Hochberg, Carmen Molina-Paris, Juan Perez-Mercader, Matt Visser

In previous work we have developed a general method for casting a classical field theory subject to Gaussian noise (that is, a stochastic partial differential equation--SPDE) into a functional integral formalism that exhibits many of the properties more commonly associated with quantum field theories (QFTs). In particular, we demonstrated how to derive the o

G. Tellez, P. J. Forrester

An exact numerical study is undertaken into the finite $N$ calculation of the free energy and distribution functions for the two-dimensional one-component plasma. Both disk and sphere geometries are considered, with the coupling $Γ$ set equal to 4 and 6. Extrapolation of our data for the free energy is consistent with the existence of a universal term ${χ\ov

Goetz S. Uhrig

Lattice modulations in the high magnetic field phase and close to impurities in spin-Peierls systems are considered and compared to experiment. Necessary extensions of existing theories are proposed. The influence of zero-point fluctuations on magnetic amplitudes is shown.

N. V. Surovtsev, J. Wiedersich, V. N. Novikov, E. R&#34;ossler

Accurate measurements of the dependence of low-frequency Raman scattering on the scattering angle were performed in two silica glasses. By a comparison of spectra measured at a large scattering angle (close to back scattering) and a small one (close to forward scattering), we for the first time observed a q-dependence of the low-frequency light scattering in

Wan-Seon Kim, W. N. Kang, S. J. Oh, Mun-Seog Kim

The Hall conductivities of HgBa_{2}CaCu_{2}O_{6+δ}and HgBa_{2}Ca_{2}Cu_{3}O_{8+δ} thin films are investigated for a magnetic field parallel to the c axis. The mixed-state Hall conductivity for these compounds is well described by σ_{xy}=C_{1}/H+C_{2}+C_{3}H. The prefactor C_1 shows a temperature dependence of the form C_1 = A(1-t)^n near T_c, where t=T/T_c i

T. Niemoeller, N. Ichikawa, T. Frello, H. Huennefeld

Superstructure reflections due to the ordering of holes into stripes in La_(1.45)Nd_(0.4)Sr_(0.15)CuO_4 have been studied with high energy x-ray diffraction. These reflections have been observed clearly for the first time in a sample which is superconducting at low temperatures (T_c = 10 K). The stripe peaks vanish above 62(5) K whereas the magnetic signal o

E. H. Visscher, D. M. Schraven, P. Hadley, J. E. Mooij

Josephson oscillations generated by a SQUID were used to measure photon assisted tunneling in a superconducting single electron tunneling (SET) transistor. The SQUID was fabricated only a few microns from the SET transistor. The close proximity of the generator to the SET transistor allowed for a continuous sweep of the excitation frequency from 10 GHz to 19

Masaaki Nakamura, Atsuhiro Kitazawa, Kiyohide Nomura

We give the details of the analysis for critical properties of spin-gap phases in one-dimensional lattice electron models. In the Tomonaga-Luttinger (TL) liquid theory, the spin-gap instability occurs when the backward scattering changes from repulsive to attractive. This transition point is shown to be equivalent to that of the level-crossing of the singlet

G. Bertotti, I. D. Mayergoyz, V. Basso, A. Magni

A general formulation of scalar hysteresis is proposed. This formulation is based on two steps. First, a generating function g(x) is associated with an individual system, and a hysteresis evolution operator is defined by an appropriate envelope construction applied to g(x), inspired by the overdamped dynamics of systems evolving in multistable free energy la

P. Exner, D. Krejcirik

We consider a quantum particle in a waveguide which consists of an infinite straight Dirichlet strip divided by a thin semitransparent barrier on a line parallel to the walls which is modeled by a $δ$ potential. We show that if the coupling strength of the latter is modified locally, i.e. it reaches the same asymptotic value in both directions along the line

Malek Zareyan, Yu. A. Kolesnichenko, A. N. Omelyanchouk

The microscopic theory of current carrying states in the ballistic superconducting microchannel is presented. The effects of the contact length L on the Josephson current are investigated. For the temperatures T close to the critical temperature T_c the problem is treated selfconsistently, with taking into account the distribution of the order parameter $Δ(r

Edo L. Kussell, Eugene I. Shakhnovich

We present an analytical method for determining the designability of protein structures. We apply our method to the case of two-dimensional lattice structures, and give a systematic solution for the spectrum of any structure. Using this spectrum, the designability of a structure can be estimated. We outline a heirarchy of structures, from most to least desig

Rahul Siddharthan

A rare example of a two dimensional Heisenberg model with an exact dimerized ground state is presented. This model, which can be regarded as a variation on the kagome lattice, has several features of interest: it has a highly (but not macroscopically) degenerate ground state; it is closely related to spin chains studied by earlier authors; in particular, it

Alexander K. Hartmann

The genetic cluster-exact approximation algorithm is an efficient method to calculate ground states of EA spin glasses. The method can be used to study ground-state landscapes by calculating many independent ground states for each realization of the disorder. The algorithm is analyzed with respect to the statistics of the ground states and the valleys of the

P. Zinn-Justin

We present a new solution of the asymmetric two-matrix model in the large $N$ limit which only involves a saddle point analysis. The model can be interpreted as Ising in the presence of a magnetic field, on random dynamical lattices with the topology of the sphere (resp. the disk) for closed (resp. open) surfaces; we elaborate on the resulting phase diagram.

Beom Jun Kim, Petter Minnhagen, Peter Olsson

Two-dimensional XY models with resistively shunted junction (RSJ) dynamics and time dependent Ginzburg-Landau (TDGL) dynamics are simulated and it is verified that the vortex response is well described by the Minnhagen phenomenology for both types of dynamics. Evidence is presented supporting that the dynamical critical exponent $z$ in the low-temperature ph

M. Markevitch, A. Vikhlinin, W. R. Forman, C. L. Sarazin

We present maps and radial profiles of the gas temperature in the nearby galaxy clusters A2199 and A496, which have the most accurate ASCA spectral data for all hot clusters. These clusters are relaxed and can provide reliable X-ray mass measurements under the assumption of hydrostatic equilibrium. The cluster average temperatures corrected for the presence

F. Yusef-Zadeh, S. Stolovy, M. Burton, M. Wardle

We present a synthesis of a number of recent observations in the near-IR H_2 and [Fe II] lines, OH (1720 MHz) maser line and various radio continuum measurements using the NICMOS of the HST, UNSWIRF on the AAT and the VLA. These observations suggest that the outer edge of the CND is collisionally excited whereas the inner edge is likely to be heated predomin

C. R. Kerton, P. G. Martin

A mid-infrared atlas of part of the Galactic plane ($75^\circ < l < 148^\circ, b = \pm6^\circ$) has been constructed using HIRES processed infrared data to provide a mid-infrared data set for the Canadian Galactic Plane Survey (CGPS). The addition of this data set to the CGPS will enable the study of the emission from the smallest components of interstellar

S. Moehler, A. V. Sweigart, W. B. Landsman, U. Heber

Atmospheric parameters (Teff, log g and log(He/H)) are derived for 42 hot horizontal branch (HB) stars in the globular cluster NGC 6752. For 19 stars MgII and FeII lines are detected indicating an iron enrichment by a factor 50 on average with respect to the cluster abundance whereas the magnesium abundances are consistent with the cluster metallicity. This

N. Balakrishnan, M. Vieira, J. F. Babb, R. C. Forrey

We present quantum mechanical and quasiclassical trajectory calculations of cross sections for rovibrational transitions in ortho- and para-H_2 induced by collisions with He atoms. Cross sections were obtained for kinetic energies between 10^-4 and 3 eV, and the corresponding rate coefficients were calculated for the temperature range 100<T<4000 K. Compariso

Sergio Campana, Davide Lazzati, Maria Rosa Panzera, Gianpiero Tagliaferri

The wavelet detection algorithm (WDA) described in the accompanying paper by Lazzati et al. is made suited for a fast and efficient analysis of images taken with the High Resolution Imager (HRI) instrument on board the ROSAT satellite. An extensive testing is carried out on the detection pipeline: HRI fields with different exposure times are simulated and an

Davide Lazzati, Sergio Campana, Piero Rosati, Maria Rosa Panzera

We present a new detection algorithm based on the wavelet transform for the analysis of high energy astronomical images. The wavelet transform, due to its multi-scale structure, is suited for the optimal detection of point-like as well as extended sources, regardless of any loss of resolution with the off-axis angle. Sources are detected as significant enhan

YBJ collaboration

ARGO-YBJ ia a detector optimized to study small size air showers. It consists of a layer of Resistive Plate counters (RPCs) covering an area of about 6500 m^2 and will be located in the Yangbajing Laboratory (Tibet, China) at 4300 m above the sea level. ARGO-YBJ will be devoted to a wide range of fundamental issues in cosmic rays and astroparticle physics, i

T. Ekholm, P. Teerikorpi, G. Theureau, M. Hanski

We derive the value of H_0 using the inverse diameter and magnitude B-band Tully-Fisher relations and the large all-sky sample KLUN (5171 spiral galaxies). Our kinematical model was that of Peebles centered at Virgo. Our calibrator sample consisted of 15 field galaxies with cepheid distance moduli measured mostly with HST. A straightforward application of th

C. S. Crawford, I. Lehmann, A. C. Fabian, M. N. Bremer

We report the detection of extended X-ray emission around several powerful 3CR quasars with redshifts out to 0.73. The ROSAT HRI images of the quasars have been corrected for spacecraft wobble and compared with an empirical point-spread function. All the quasars examined show excess emission at radii of 15 arcsec and more; the evidence being strong for the m

Colin B. Roald

I will discuss an attempt at representing an interface dynamo in a simplified, essentially 1D framework. The operation of the dynamo is broken up into two 1D layers, one containing the $α$ effect and the other containing the $ω$ effect, and these two layers are allowed to communicate with each other by the simplest possible representation of diffusion, an an

Jeffrey A. Newman, Stephen E. Zepf, Marc Davis, Wendy L. Freedman

In an attempt to use Cepheid variables to determine the distance to the Centaurus cluster, we have obtained images of NGC 4603 with the Hubble Space Telescope on 9 epochs using WFPC2 and the F555W and F814W filters. This galaxy has been suggested to lie within the ``Cen30&#39;&#39; portion of the cluster and is the most distant object for which this method h

R. Balbinot, A. Fabbri, I. Shapiro

The characteristic features of $<T_{μν}>$ in the Boulware, Unruh and Hartle-Hawking states for a conformal massless scalar field propagating in the Schwarzschild space-time are obtained by means of effective actions deduced by the trace anomaly. The actions are made local by the introduction of auxiliary fields and boundary conditions are carefully imposed o

Yuri N. Obukhov, Friedrich W. Hehl

The Maxwell equations are formulated on an arbitrary (1+3)-dimensional manifold. Then, imposing a (constrained) linear constitutive relation between electromagnetic field $(E,B)$ and excitation $({\cal D},{\cal H})$, we derive the metric of spacetime therefrom.

Minghong G. Wu, Michael W. Deem

We present a new method, the analytical rebridging scheme, for Monte Carlo simulation of proline-containing, cyclic peptides. The cis/trans isomerization is accommodated by allowing for two states of the amide bond. We apply our method to five peptides that have been previously characterized by NMR methods. Our simulations achieve effective equilibration and

E. V. Gorbar

By using the Nambu-Jona-Lasinio model, we study dynamical symmetry breaking in spaces with constant negative curvature. We show that the physical reason for zero value of critical coupling value $g_c = 0$ in these spaces is connected with the effective reduction of dimension of spacetime $1 + D \to 1 + 1$ in the infrared region, which takes place for any dim

P. Eden, G. Gustafson, V. A. Khoze

A thorough verification of the distinct differences in the properties of quark and gluon jets is considered as one of the most instructive tests of the basic ideas of QCD. In the real life experiments such a comparison appears to be quite a delicate task and various subtle issues require further theoretical efforts. In this paper we discuss in detail the pos

Semyon Alesker, Maxim Braverman

Let $M$ be a compact symplectic manifold on which a compact torus $T$ acts Hamiltonialy with a moment map $μ$. Suppose there exists a symplectic involution $θ:M\to M$, such that $μ\circθ=-μ$. Assuming that 0 is a regular value of $μ$, we calculate the trace of the action of $θ$ on the cohomology of $M$ in terms of the trace of the action of $θ$ on the symple

Matthias Blau, Edi Gava, K. S. Narain

In the context of the AdS/CFT correspondence, we perform a direct computation in AdS_5 supergravity of the trace anomaly of a d=4, N=2 SCFT. We find agreement with the field theory result up to next to leading order in the 1/N expansion. In particular, the order N gravitational contribution to the anomaly is obtained from a Riemann tensor squared term in the

Dafne Guetta, Paul Singer

We study the novel decays $B^{*}\to Bγγ$ and $D^{*}\to Dγγ$ using the framework of the Heavy Meson Chiral Lagrangian (HM$χ$L) to leading order in chiral perturbation theory. The branching ratios of these decays are expressed in terms of the strong $g_{B^{*}(D^{*})B(D)π}$ and the electromagnetic $g_{B^{*}(D^*)B(D)γ}$ couplings, thus providing a possible tool

Ram Brustein

A classical and quantum mechanical generalized second law of thermodynamics in cosmology implies constraints on the effective equation of state of the universe in the form of energy conditions, obeyed by many known cosmological solutions, and is compatible with entropy bounds which forbid certain cosmological singularities. In string cosmology the second law

R. Citro, E. Orignac, N. Andrei, C. Itoi

We show that the low-energy physics of the spin-tube model in presence of a critical magnetic field can be described by a broken SU(3) spin chain. Using the Lieb-Schultz-Mattis Theorem we characterize the possible magnetization plateaus and study the critical behavior in the region of transition between the plateaus m=1/2 and m=3/2 by means of renormalizatio

J. S. B. Wyithe, R. L. Webster, E. L. Turner, D. J. Mortlock

Following the detection of a gravitational microlensing high magnification event (HME) in Q2237+0305A attempts have been made to place limits on the dimensions of the quasar continuum source. The analyses have studied either the observed event magnitude or the event duration. The latter approach has been hampered by lack of knowledge about the transverse vel

Patrick Bruno

The structure and properties of a geometrically constrained magnetic wall in a constriction separating two wider regions are investigated theoretically. They are shown to differconsiderably from those of an unconstrained wall, so that the geometrically constrained magnetic wall truly constitutes a new kind of magnetic wall, besides the well known Bloch and N

J. S. B. Wyithe, R. L. Webster, E. L. Turner

Gravitational microlensing at cosmological distances is potentially a powerful tool for probing the mass functions of stars and compact objects in other galaxies. In the case of multiply-imaged quasars, microlensing data has been used to determine the average microlens mass. However the measurements have relied on an assumed transverse velocity for the lensi

Björn Brinne, Svend E. Hjelmeland, Ulf Lindström

We derive manifestly locally supersymmetric extensions of the Born-Infeld action with $p=2$. The construction is based on a first order bosonic action for $Dp$-branes with a generalized Weyl invariance.

A. V. Kuznetsov, N. V. Mikheev

The total set of the neutrino - electron processes in a presence of both components of an active medium, hot dense plasma and strong magnetic field, is investigated for the first time. The contribution of the processes $νe^- \to νe^-$, $νe^+ \to νe^+$, $ν\to νe^- e^+$, $νe^- e^+ \to ν$ is shown to dominate and not to depend on the chemical potential of elect

Yuri Bespalov, Bernhard Drabant

This is the central article of a series of three papers on cross product bialgebras. We present a universal theory of bialgebra factorizations (or cross product bialgebras) with cocycles and dual cocycles. We also provide an equivalent (co-)modular co-cyclic formulation. All known examples as for instance bi- or smash, doublecross and bicross product bialgeb

G. S. Agarwal

We demonstrate in a very general fashion, considerable slowing down of decoherence and relaxation by fast frequency modulation of the system heat bath coupling. The slowing occurs as the decoherence rates are now determined by the spectral components of bath correlations which are shifted due to fast modulation. We present several examples including the slow

M. Hassaïne, P. A. Horváthy

As found by Bordemann and Hoppe and by Jevicki, a certain non-relativistic model of an irrotational and isentropic fluid, related to membranes and to partons, admits a Poincaré symmetry. Bazeia and Jackiw associate this dynamical symmetry to a novel type of ``field dependent&#39;&#39; action on space-time. The ``Kaluza-Klein type&#39;&#39; framework of Duval

S. Ulrych

A new relativistic description of quantum electrodynamics is presented. Guideline of the theory is the Klein-Gordon equation, which is reformulated to consider spin effects. This is achieved by a representation of relativistic vectors with a space-time algebra made up of Pauli matrices and hyperbolic numbers. The algebra is used to construct the differential

R. Horvat

An extremely light ($m_ϕ \ll 10^{-33} {\rm eV}$), slowly-varying scalar field $ϕ$ (quintessence) with a potential energy density as large as 60% of the critical density has been proposed as the origin of the accelerated expansion of the Universe at present. The interaction of this smoothly distributed component with another predominately smooth component, th

Martin Lüscher

Starting from the Ginsparg-Wilson relation, a general construction of chiral gauge theories on the lattice is described. Local and global anomalies are easily discussed in this framework and a closed expression for the effective action can be obtained. Particular attention is paid to the non-abelian gauge anomaly, which is shown to be related to a local topo

Hideo Iguchi, Tomohiro Harada, Ken-ichi Nakao

It has been suggested that a naked singularity may be a good candidate for a strong gravitational wave burster. The naked singularity occurs in the generic collapse of an inhomogeneous dust ball. We study odd-parity mode of gravitational waves from a naked singularity of the Lema\^ıtre-Tolman-Bondi space-time. The wave equation for gravitational waves are so

Sasanka Ghosh, Sudipta Nandy

We show the complete integrability and the existence of optical solitons of higher order nonlinear Schrodinger equation by inverse scattering method for a wide range of values of coefficients. This is achieved first by invoking a novel connection between the integrability of a nonlinear evolution equation and the dimensions of a family of matrix Lax pairs. I

Sumiyoshi Abe, A. K. Rajagopal

The problem of quantum state inference and the concept of quantum entanglement are studied using a non-additive measure in the form of Tsallis entropy indexed by the positive parameter q. The maximum entropy principle associated with this entropy along with its thermodynamic interpretation are discussed in detail for the Einstein-Podolosky-Rosen pair of two

P. Facchi, A. Mariano, S. Pascazio

We analyze the coherence properties of a cold or a thermal neutron by utilizing the Wigner quasidistribution function. We look in particular at a recent experiment performed by Badurek {\em et al.}, in which a polarized neutron crosses a magnetic field that is orthogonal to its spin, producing highly non-classical states. The quantal coherence is extremely s

A. F. Gomes, J. A. Roversi, A. Vidiella-Barranco

We propose a two-photon micromaser-based scheme for the generation of a nonclassical state from a mixed state. We conclude that a faster, as well as a higher degree of field purity is achieved in comparison to one-photon processes. We investigate the statistical properties of the resulting field states, for initial thermal and (phase-diffused) coherent state

L. Accardi, S. V. Kozyrev, I. V. Volovich

A model of particle interacting with quantum field is considered. The model includes as particular cases the polaron model and non-relativistic quantum electrodynamics. We compute matrix elements of the evolution operator in the stochastic approximation and show that depending on the state of the particle one can get the non-exponential decay with the rate t

Sayan Kar, Avinash Khare

The toy model of a particle on a vertical rotating circle in the presence of uniform gravitational/ magnetic fields is explored in detail. After an analysis of the classical mechanics of the problem we then discuss the quantum mechanics from both exact and semi--classical standpoints. Exact solutions of the Schrodinger equation are obtained in some cases by

Ulrich Mohrhoff

It is widely accepted that a Born probability of 1 is sufficient for the existence of a corresponding element of reality. Recently Vaidman has extended this idea to the ABL probabilities of the time-symmetrized version of quantum mechanics originated by Aharonov, Bergmann, and Lebowitz. Several authors have objected to Vaidman&#39;s time-symmetrized elements

H. C. Rosu

A simple version of the q-deformed calculus is used to generate a pair of q-nonlocal, second-order difference operators by means of deformed counterparts of Darboux intertwining operators for zero factorization energy. These deformed non-local operators may be considered as supersymmetric partners and their structure contains contributions originating in bot

U. A. Yajnik

A glorious achievement of twentieth century Physics is the identification of the building blocks of nature. A related triumph a deep understanding of the forces of interaction. In particular, it has been possible to understand the four fundamental forces of nature in an elegant and unified mathematical framework. The paradigm for this unification has been th

Franco Bassani, Valerio Lucarini

The nonlinear oscillator model is useful to basically understand the most important properties of nonlinear optical processes. It has been shown to give the correct asymptotic behaviour and to provide the general feature of harmonic generation to all orders, in particular dispersion relations and sum rules. We investigate the properties of Pump and Probe pro

B. R. Schlei

In 1996, D.H. Rischke and M. Gyulassy proposed to use the time-delay signal in Bose-Einstein correlations (BEC) as a signature for the possible formation of a quark-gluon plasma (QGP) in relativistic heavy-ion collisions. In particular, they suggested to measure the ratio of the transversal interferometry radii, $R_{out}/R_{side}$, which can be obtained by f

Michael Baake, Uwe Grimm, Dieter Joseph

Trace maps of two-letter substitution rules are investigated with special emphasis on the underlying algebraic structure and on the existence of invariants. We illustrate the results with the generalized Fibonacci chains and show that the well-known Fricke character I(x,y,z) = x^2 + y^2 + z^2 - 2 x y z - 1 is not the only type of invariant that can occur. We

C. Kuelske

We consider disordered lattice spin models with finite volume Gibbs measures $μ_Ł[η](d\s)$. Here $\s$ denotes a lattice spin-variable and $η$ a lattice random variable with product distribution $¶$ describing the disorder of the model. We ask: When will the joint measures $\lim_{Ł\uparrow\Z^d}¶(dη)μ_Ł[η](d\s)$ be [non-] Gibbsian measures on the product of sp