March 2001 arXiv papers — page 12

S. Sakhi

We examine theoretically the effects caused by a periodic external potential on the correlated motion of a two-dimensional electron system under strong magnetic fields corresponding to a filling factor 1/2. To describe the resulting complex dynamics, we adopt a composite fermion approach and we determine in a two loop approximation the density-response funct

F. Mazzanti, A. Polls

A detailed calculation of the real part of the finite temperature dynamic susceptibility of the free Bose gas is presented. After a short discussion on the different ways in which it can be calculated for temperatures above and below the Bose--Einstein transition temperature, its main properties and its evolution with $q$ and $T$ are analyzed. Finally, expre

Upendra Harbola, Shankar P. Das

We have studied the relation between the structural relaxation and the frequency dependent thermal response or the specific heat, $c_p(ω)$, in a supercooled liquid. The Mode Coupling Theory (MCT) results are used to obtain $c_p(ω)$ corresponding to different wavevectors. Due to the two-step relaxation process present in the MCT, an extra peak, in addition to

Sudha Srivastava, Shankar P. Das

In the present work we compute the enhancement in the long time transport coefficients due to correlated motion of fluid particles at high density. The fully wave vecor dependent extended mode coupling model is studied with the inclusion of an additional slow variable of the defect density for the amorphous system. We use the extremely slow relaxation of the

M. Y. Choi, J. Choi

We consider the conductivity quantization in two-dimensional arrays of mesoscopic Josephson junctions, and examine the associated degeneracy in various regimes of the system. The filling factor of the system may be controlled by the gate voltage as well as the magnetic field, and its appropriate values for quantization is obtained by employing the Jain hiera

Michael Galperin, Abraham Nitzan, Uri Peskin

The traversal time for tunneling is a measure of the time during which the transmitted particle can be affected by interactions localized in the barrier. The Buttiker-Landauer approach, which estimates this time by imposing an internal clock on the system, has been applied so far for relatively simple 1-dimensional models. Here we apply this approach to esti

A. Nitzan

This note discusses the relationship between a given intramolecular bridge assisted electron transfer rate and the corresponding zero bias molecular conduction of the same molecular species.

R. Moessner, S. L. Sondhi, Eduardo Fradkin

Quantum dimer models are believed to capture the essential physics of antiferromagnetic phases dominated by short-ranged valence bond configurations. We show that these models arise as particular limits of Ising (Z_2) gauge theories, but that in these limits the system develops a larger local U(1) invariance that has different consequences on different latti

Martin Zwaan

Five galaxy groups with properties similar to those of the Local Group have been surveyed for HI clouds with the Arecibo Telescope. In total 300 pointings have been observed on grids of approximately 2.5 x 1.5 Mpc centred on the groups. The 4.5 sigma detection limit on the minimal detectable HI masses is approximately 7 x 10^6 M_sun (H_0=65). All detections

A. Del Popolo, M. Gambera, E. Nihal Ercan

Planets orbiting a planetesimal circumstellar disc can migrate inward from their initial positions because of dynamical friction between planets and planetesimals. The migration rate depends on the disc mass and on its time evolution. Planets that are embedded in long-lived planetesimal discs, having total mass of $10^{-4}-0.01 M_{\odot}$, can migrate inward

Henry E. Kandrup, Ioannis V. Sideris

This paper summarises a numerical investigation of the statistical properties of orbits evolved in `frozen,&#39; time-independent N-body realisations of smooth, time-independent density distributions, allowing for 10^(2.5)<N<10^(5.5). Two principal conclusions were reached: (1) In the limit of a nearly `unsoftened&#39; two-body kernel, the value of the large

C. J. Virtue

The Sudbury Neutrino Observatory (SNO) has unique capabilities as a supernova detector. In the event of a galactic supernova there are opportunities, with the data that SNO would collect, to constrain certain intrinsic neutrino properties significantly, to test details of the various models of supernova dynamics, and to provide prompt notification to the ast

C. D. Dermer

Simple arguments concerning power and acceleration efficiency show that ultra-high energy cosmic rays (UHECRS) with energies >~ 10^{19} eV could originate from GRBs. Neutrons formed through photo-pion production processes in GRB blast waves leave the acceleration site and travel through intergalactic space, where they decay and inject a very energetic proton

Patricia T. Boyd, Alan P. Smale, Joseph F. Dolan

The black-hole binary LMC X-3 is known to be variable on time scales of days to years. We investigate X-ray and ultraviolet variability in the system as a function of the 1.7 day binary phase using a 6.4 day observation with the Rossi X-ray Timing Explorer (RXTE) from December 1998. An abrupt 14% flux decrease, lasting nearly an entire orbit, is followed by

Andrei M. Beloborodov

Models of X-ray production in black-hole sources are reviewed and compared with recent observations. Possible diagnostics of the hot-disk and disk-corona models are discussed in the light of spectral and temporal data. A new model of a small-scale inviscid accretion disk is presented.

G. S. Bisnovatyi-Kogan

The present common view about GRB origin is related to cosmology. There are two evidences in favour of this interpretation. The first is connected with statistics, the second is based on measurements of the redshifts in the GRB optical afterglows. Red shifts in optical afterglows had been observed only in long GRB. Statistical errors, and possibility of gala

E. Carretti, R. Tascone, S. Cortiglioni, J. Monari

An extended analysis of some instrumental polarisation sources has been done, as a consequence of the renewed interest in extremely sensitive polarisation measurements stimulated by Cosmic Microwave Background experiments. The case of correlation polarimeters, being them more suitable than other configurations, has been studied in detail and the algorithm ha

Anne-Marie Dumont, Suzy Collin

We describe a code designed for hot media {(T $\ge$} a few 10$^4$ K), optically thick to Compton scattering. It computes the structure of a plane-parallel slab of gas in thermal and ionization equilibrium, illuminated on one side or on both sides by a given spectrum. This code has been presented in a previous paper (Dumont, Abrassart & Collin 2000), where se

M. Salaris, S. Cassisi, E. Garcia-Berro, J. Isern

We analyze in detail various possible sources of systematic errors on the distances of globular clusters derived by fitting a local template DA white dwarf sequence to the cluster counterpart (the so-called WD-fitting technique). We find that the unknown thickness of the hydrogen layer of white dwarfs in clusters plays a non negligible role. For reasonable a

Jose A. Gonzalez, Hernando Quevedo, Marcelo Salgado, Daniel Sudarsky

We analyze the observational constraints on the effective Brans-Dicke parameter and on the temporal variation of the effective gravitational constant within the context of the oscillating G model, a cosmological model based on a massive scalar field non-minimally coupled to gravity. We show that these local constraints cannot be satisfied simultaneously once

T. A. Lozinskaya, A. V. Moiseev, V. L. Afanasiev, E. Wilcots

Observations of the nebula S3 associated with the WO star in the galaxy IC 1613 and of an extended region surrounding S3 are reported. The star and bright core of the nebula were observed with a multipupil fiber spectrograph mounted on the 6-m telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences. Images in the principle spect

M. Takami, J. Bailey, T. M. Gledhill, A. Chrysostomou

We have used the technique of spectro-astrometry to study the milli-arcsecond scale structure of the emission lines in the T Tauri star RU Lupi. The wings of the H-alpha emission are found to be displaced from the star towards the south-west (blue wing) and north-east (red wing) with angular scales of 20-30 milli-arcsecs. This structure is consistent with a

I. Baraffe, Y. Alibert

We present theoretical period - magnitude relationships for Cepheids in different filters for fundamental and first overtone pulsators, completing the work by Alibert et al. (1999). The results are provided for different metallicities characteristic of the Magellanic Clouds and the Milky Way. In contrast to the fundamental mode, we find a small metallicity e

L. B. Leinson, A. Perez

We present a method to calculate $ν\barν$ energy losses from neutron star crusts, which automatically takes into account for collective effects, and allows to calculate the total emissivity without a separate consideration of particular processes. We show that the formula we obtain describe the known results for the emissivity due to plasmon decay and Bremss

L. B. Leinson, A. Perez

We have investigated the bound states of an electron and positron in superstrong magnetic fields typical for neutron stars. The complete relativistic problem of positronium in a strong magnetic field has not been succesfully solved up to now. In particular, we have studied the positronium when it moves relativistically across the magnetic field. A number of

Davide Lazzati, Gabriele Ghisellini, Francesco Haardt, Alberto Fernandez-Soto

The nature of Gamma-Ray Burst progenitors is still a debated issue, but consensus is growing on the association of GRBs with massive stars. Furthermore, current models for the reionization of the universe consider massive Pop--III stars as the sources of the ionizing photons. There could then be a natural link between GRBs and reionization. The reionization

David Kirkman, David Tytler, John M. O&#39;Meara, Scott Burles

The z ~ 0.701 absorption system towards the QSO PG1718+4807 is the only example of a QSO absorption system which might have a deuterium/hydrogen ratio approximately ten times the value found towards other QSOs. We have obtained new STIS spectra from the Hubble Space Telescope of the Lyman alpha and Lyman limit regions of the system. These spectra give the re

Suzy Collin, Jean-Marc Hure

We address the question of the relations between the black hole&#39;s mass, the accretion rate, the bolometric luminosity, the optical luminosity and the size of the Broad Line Region (BLR) in Active Galactic Nuclei, using recent observational data obtained from monitoring campaigns. We show that a standard accretion disc cannot account for the observed opti

M. S. Oey, C. J. Clarke, P. Massey

The current understanding of mechanical feedback is reviewed by evaluating the standard, adiabatic model for shell formation and evolution. This model is relevant to phenomena ranging from individual stellar-wind bubbles to galactic superwinds, forming the basis for our understanding of the multiphase ISM, IGM, and galactic evolutionary processes. Although s

Edmund Bertschinger

This paper describes the generation of initial conditions for numerical simulations in cosmology with multiple levels of resolution, or multiscale simulations. We present the theory of adaptive mesh refinement of Gaussian random fields followed by the implementation and testing of a computer code package performing this refinement called GRAFIC2. This packag

B. J. Carr

We discuss recent developments in the study of primordial black holes, focussing particularly on their formation and quantum evaporation. Such studies can place important constraints on models of the early Universe. An especially interesting development has been the realization that such constraints may be severely modified if the value of the gravitational

B. J. Carr

Cosmological nucleosynthesis calculations imply that many of the baryons in the Universe must be dark. We discuss the likelihood that some of these dark baryons may reside in galaxies as Massive Compact Halo Objects (MACHOs), the remnants of a first generation of pregalactic or protogalactic stars. Various candidates have been proposed for such remnants and

L. G. Balazs, P. Meszaros, Z. Bagoly, I. Horvath

We argue that the distributions of both the intrinsic fluence and the intrinsic duration of the gamma-ray emission in gamma-ray bursts from the BATSE sample are well represented by log-normal distributions, in which the intrinsic dispersion is much larger than the cosmological time dilatation and redshift effects. We perform separate bivariate log-normal dis

V. Berezinsky, B. Hnatyk, A. Vilenkin

Cusps of superconducting strings can serve as GRB engines. A powerful beamed pulse of electromagnetic radiation from a cusp produces a jet of accelerated particles, whose propagation is terminated by the shock responsible for GRB. A single free parameter, the string scale of symmetry breaking $η\sim 10^{14} GeV$, together with reasonable assumptions about th

Dongsu Bak, Kimyeong Lee

We investigate supersymmetric tubular configurations in the matrix theory. We construct a host of BPS configurations of eight supersymmetries. They can be regarded as cylindrical D2 branes carrying nonvanishing angular momentum. For the simplest tube, the world volume can be described as noncommutative tube and the world volume dynamics can be identified as

Steven Weinberg

General asymptotic formulas are given for the coefficient $C_\ell$ of the term of multipole number $\ell$ in the temperature correlation function of the cosmic microwave background, in terms of scalar and dipole form factors introduced in a companion paper. The formulas apply in two overlapping limits: for $\ell\gg 1$ and for $\ell d/d_A\ll 1$ (where $d_A$ i

C. M. Newman, D. L. Stein

We present a detailed proof of a previously announced result (C.M. Newman and D.L. Stein, Phys. Rev. Lett. v. 84, pp. 3966--3969 (2000)) supporting the absence of multiple (incongruent) ground state pairs for 2D Edwards-Anderson spin glasses (with zero external field and, e.g., Gaussian couplings): if two ground state pairs (chosen from metastates with, e.g.

Steven Weinberg

It is shown that the fluctuation in the temperature of the cosmic microwave background in any direction may be evaluated as an integral involving scalar and dipole form factors, which incorporate all relevant information about acoustic oscillations before the time of last scattering. A companion paper gives asymptotic expressions for the multipole coefficien

Duane A. Dicus, Stefan Kretzer, Wayne W. Repko, Carl Schmidt

Unitarity relates the total cross section for neutrino-nucleon scattering to the neutrino-nucleon forward scattering amplitude. Assuming the validity of the perturbative expansion of the forward amplitude in the {\em weak} coupling constant, we derive a unitarity bound on the inelastic cross section. The inelastic cross section saturates this bound at a typi

David Atwood, Amarjit Soni

Recent experimental observations of CP asymmetry in B0 -> psi K0 constitute the first significant signal of CP violation outside the neutral kaon system; thus they represent an important milestone to test the CKM paradigm. We, therefore, undertake a critical appraisal of the existing experimental and theoretical inputs used to deduce constraints on sin(2 bet

N. Masetti

The GRB010222 optical and near-infrared (NIR) afterglow was monitored at the TNG and other Italian telescopes starting ~1 day after the high-energy prompt event. The optical BVR light curves, which are the best sampled, are continuously steepening, and can be described by two power laws, f(t) = t^(-alpha), of indices alpha_1 ~ 0.7 and alpha_2 ~ 1.3 before an

Claudio Arezzo, Andrea Loi

In this paper we prove that, under natural assumptions, the scalar curvature of a Kaehler-Einstein metric on a compactification of C^n is strictly positive.

Igor Bandos, Paolo Pasti, Andrey Pokotilov, Dmitri Sorokin

We discuss a four-dimensional Volkov-Akulov supersymmetric theory on a D3-brane with N=2 supersymmetry broken down to N=1.

P. Di Bari, R. Foot

It is well established that active-sterile neutrino oscillations generate large neutrino asymmetries for very small mixing angles ($\sin^2 2θ_0\lesssim 10^{-4}$), negative values of $δm^2$ and provided that $|δm^2|\gtrsim 10^{-4} {\rm eV^2}$. By numerically solving the quantum kinetic equations, we show that the generation still occurs at much lower values o

S. Bellucci, E. Ivanov, S. Krivonos

We describe, on a few instructive examples, a systematic way of deducing the superfield equations of motion of superbranes in the approach of partial breaking of global supersymmetry (PBGS) from the nonlinear-realizations formalism. For D-branes these equations simultaneously represent the appropriate supersymmetric Born-Infeld theories. We also discuss how

Paolo Cea, Leonardo Cosmai

We study Abelian monopole and vortex condensation in lattice pure gauge theories. Condensation is detected by means of a disorder parameter defined in terms of a gauge-invariant effective action introduced using the lattice Schrödinger functional. Dirac monopoles condense in the confined phase of U(1) lattice gauge theory. Abelian monopoles and Abelian vorti

P. Bozhilov

We show how the classical string dynamics in $D$-dimensional gravity background can be reduced to the dynamics of a massless particle constrained on a certain surface whenever there exists at least one Killing vector for the background metric. We obtain a number of sufficient conditions, which ensure the existence of exact solutions to the equations of motio

R. D&#39;Auria, S. Ferrara

In any low energy effective supergravity theory general formulae exist which allow one to discuss fermion masses, the scalar potential and breaking of symmetries in a model independent set up. A particular role in this discussion is played by Killing vectors and Killing prepotentials. We outline these relations in general and specify then in the context of N

PACS Collaboration, A. Ali Khan, S. Aoki, R. Burkhalter

We present a study of leptonic $B$ meson decay constants in lattice QCD with two flavors ($N_f=2$) of light dynamical quarks using NRQCD for the heavy quark. Gauge configurations are generated with a renormalization-group improved gauge action and a meanfield-improved clover light quark action. Measurements are carried out at two values of $β=6/g^2$, each fo

A. Dumitru, L. Frankfurt, L. Gerland, H. Stöcker

We calculate prompt photon production in high-energy nuclear collisions. We focus on the broadening of the intrinsic transverse momenta of the partons in the initial state from nuclear effects, and their influence on the prompt photon p_t distribution. Comparing to WA98 data from Pb+Pb collisions at SPS energy we find evidence for the presence of nuclear bro

Eiichi Mitsuda, Ken Sasaki

The virtual effects of the Zee charged scalar boson on the lepton-family-number (LFN) violating processes are studied. We obtain the constraints on the individual Yukawa coupling constants of the Zee boson to leptons. Using these constraints, we predict the upper bounds on the muonium-antimuonium conversion probability, the branching fractions of the LFN vio

Steen Hannestad, Georg Raffelt

If large extra dimensions exist in nature, supernova (SN) cores will emit large fluxes of Kaluza-Klein gravitons, producing a cosmic background of these particles with energies and masses up to about 100 MeV. Radiative decays then give rise to a diffuse cosmic gamma-ray background with E_gamma < 100 MeV which is well in excess of the observations if more tha

R. Horvat

Recently, it has been shown that cosmic neutrino flux at the GRB/AGN source, $F_{ν_e}^0 : F_{ν_μ}^0 : F_{ν_τ}^0 \simeq 1 :2 :0 $, inevitably oscillates (in the three neutrino framework) to 1 : 1: 1, irrespective of the mixing angle relevant to the solar data. It has also been pointed out that the intrinsic flux of the cosmic high-energy neutrinos may not hav

J. Klos, S. Kobe

Using the zero-temperature Metropolis dynamics, the time decay of the remanent magnetization in the $\pm J$ Edward-Anderson spin glass model with a uniform random distribution of ferromagnetic and antiferromagnetic interactions has been investigated. Starting from the saturation, the magnetization per spin $m$ reveals a slow decrease with time, which can be

Stephan Narison

We present a new independent evaluation of the hadronic vacuum polarization contributions a_l{had}(l.o)=(1/2)(g-2)_l{had}(l.o) to the anomalous magnetic moment (anomaly) of the muon and tau leptons using tau-decays and e+e- data. The alone theoretical input used for describing the high-energy region not accessible experimentally is perturbative QCD plus (neg

Y. Tanuma, K. Kuroki, Y. Tanaka, S. Kashiwaya

Quasiparticle states near the surface of a quasi-one-dimensional organic superconductor $({TMTSF})_{2}{PF}_6$ are studied based on an extended Hubbard model on a quasi-one dimensional lattice at quarter-filling. Three types of pairing symmetries, (i) p-wave, (ii) d-wave, or (iii) $f$-wave are assumed. The resulting surface density of states has characteristi

S. E. Parkhomenko

BRST construction of $D$-branes in SU(2) WZW model is proposed.

Da Qing Liu, Ji Min Wu, Ying Chen

We develop a new approach to construct the operator on lattice for the calculation of glueball mass, which is based on the connection between the continuum limit of the chosen operator and the quantum number $J^{PC}$ of the state studied. The spin of the state studied is then determined uniquely and directly in numerical simulation. Furthermore, the approach

Won Tae Kim, John J. Oh, Young-Jai Park

We calculate the entropy of the brane-world black hole in the Randall-Sundrum(RS) model by using the brick-wall method. The modes along the extra dimension are semi-classically quantized on the extra dimension. The number of modes in the extra dimension is given as a simple form with the help of the RS mass relation, and then the entropy for the scalar modes

Yoshifumi Hyakutake

We find new solutions corresponding to torus-like generalization of dielectric D2-brane from the viewpoint of D2-brane action and N D0-branes one. These are meta-stable and would decay to the spherical dielectric D2-brane.

Yutaka Hosotani

Scaling behavior in the moduli space of monopole and dyon solutions in the Einstein-Yang-Mills theory in the asymptotically anti-de Sitter space is derived. The mass of monopoles and dyons scales with respect to their magnetic and electric charges, independent of the values of the cosmological constant and gauge coupling constant. The stable monopole and dyo

Kenichi Kasamatsu, Yukinori Yasui, Makoto Tsubota

We show theoretically the existence of a metastable state and the possibility of decay to the ground state through macroscopic quantum tunneling in two-component Bose-Einstein condensates with repulsive interactions. Numerical analysis of the coupled Gross-Pitaevskii equations clarifies the metastable states whose configuration preserves or breaks the symmet

M. B. Plenio

In recent years a significant amount of research in quantum optics has been devoted to the analysis of atomic three-level systems and for many physical quantities the same effects have been predicted for different configurations. These configurations can be split into essentially two classes. One for which the system contains a metastable state and another w

M. B. Plenio, V. Vitelli

This article discusses the concept of information and its intimate relationship with physics. After an introduction of all the necessary quantum mechanical and information theoretical concepts we analyze Landauer&#39;s principle that states that the erasure of information is inevitably accompanied by the generation of heat. We employ this principle to rederi

Holger F. Hofmann, Takayoshi Kobayashi, Akira Furusawa

In conventional quantum nondemolition measurements, the interaction between signal and probe preserves the measured variable. Alternatively, it is possible to restore the original value of the variable by feedback. In this paper, we describe a quantum nondemolition measurement of a quadrature component of the light field using a feedback compensated beam spl

Wim van Dam

In this article we investigate how we can employ the structure of combinatorial objects like Hadamard matrices and weighing matrices to device new quantum algorithms. We show how the properties of a weighing matrix can be used to construct a problem for which the quantum query complexity is ignificantly lower than the classical one. It is pointed out that th

P. Fonte, V. Peskov

In this work we describe some recent results concerning the application of Resistive Plate Chambers operated in avalanche mode at atmospheric pressure for high-resolution time-of-flight measurements. A combination of multiple, mechanically accurate, thin gas gaps and state-of-the-art electronics yielded an overall (detector plus electronics) timing accuracy

T. Dudas

This paper deals with QED-particles and the interaction between them on a classical level. The Maxwell-equations are used mainly. (Proofs are not used in a mathematical but intuitive sense.) In the first step the main statements are presented. The corresponding proofs are given in the second and final step. Main statements: I. An electron/positron is a sink/

G. Dattoli, A. Doria, G. P. Gallerano, L. Giannessi

The study presented here was initiated by a discussion to investigate the possibility of using synchrotron radiation as a source for the Next Generation Lithography (NGL) based on the EUV-concept (Extreme Ultra-Violet; here 13.5 nm or 11.3 nm radiation, respectively). The requirements are: 50 W, 2% bandwidth and minimal power outside this bandwidth. Three op

Peeter Saari

Presented is an overview of electromagnetic versions of the so-called X-type waves intensively studied since their invention in early 1990.-ies in ultrasonics. These waves may be extremely localized both laterally and longitudinally and - what has been considered as most startling - propagate superluminally without apparent spread. Spotlighted are the issues

R. Milot, A. W. Kleyn, A. P. J. Jansen

We present classical trajectory calculations of the rotational vibrational scattering of a non-rigid methane molecule from a Ni(111) surface. Energy dissipation and scattering angles have been studied as a function of the translational kinetic energy, the incidence angle, the (rotational) nozzle temperature, and the surface temperature. Scattering angles are

V. E. Cachorro, L. L. Salcedo

New improvements to compute Mie scattering quantities are presented. They are based on a detailed analysis of the various sources of error in Mie computations and on mathematical justifications. The algorithm developed on these improvements proves to be reliable and efficient, without size ($x=2πR/λ$) nor refractive index ($m=m_R-{\rm i}m_I$) limitations, an

R. I. Khrapko

Does the mass of bodies depend on their velocity? Is the mass additive if separate bodies are joined together to form a composite system? Is the mass of an isolated system conserved? Different teachers of physics and specialists give different answers to these questions because there is no general agreement on the definition of mass..We shall show that the n

Michael K. Rivera

This thesis presents an experimental study of the inverse energy cascade as it occurs in an electromagnetically forced soap film. It focuses on characterizing important features of the inverse cascade such as it&#39;s range, how energy is distributed over the range and how energy flows through the range. The thesis also probes the assumption of scale invaria

R. Surman, J. Engel

We explore changes in abundance patterns that occur late in the r process. As the neutrons available for capture begin to disappear, a quasiequilibrium funnel shifts material into the large peaks at A=130 and A=195, and into the rare-earth &#34;bump&#34; at A=160. A bit later, after the free-neutron abundance has dropped and beta-decay has begun to compete s

Andrey A. Sukhorukov, Nail N. Akhmediev

We obtain an accurate estimate for the peak intensities of multi-soliton complexes for a Kerr-type nonlinearity in the (1+1) - dimension problem. Using exact analytical solutions of the integrable set of nonlinear Schrodinger equations, we establish a rigorous relationship between the eigenvalues of incoherently-coupled fundamental solitons and the range of

B. Feigin, R. Kedem, S. Loktev, T. Miwa

We consider two types of quotients of the integrable modules of $\hat{sl}_2$. These spaces of coinvariants have dimensions described in terms of the Verlinde algebra of level-$k$. We describe monomial bases for the spaces of coinvariants, which leads to a fermionic description of these spaces. For $k=1$, we give the explicit formulas for the characters. We a

Nikolai Dokuchaev

We consider strategies of investments into options and diffusion market model. It is shown that there exists a correct proportion between &#34;put&#34; and &#34;call&#34; in the portfolio such that the average gain is almost always positive for a generic Black and Scholes model. This gain is zero if and only if the market price of risk is zero. It is discuss

Petrequin Denis

In this paper, I construct Chern classes in the rigid cohomology of P. Berthelot. We start by constructing Chern classes for proper varieties. To prove all the properties we have to reinterpret the construction in a crystalline way. Then we can deal with open varieties using a compactification theorem.

Aaron Bertram

An analogy is drawn between recent work with Kley (math.AG/0007082) and the WDVV equations. That is, both are regarded as symmetries of generating functions with coefficients that &#34;count&#34; rational curves on a complex projective manifold. It is shown how to obtain the string, dilaton and divisor equations from the new symmetries, as well as an analogu

Peter Brinkmann, Saul Schleimer

We present the mathematical background of a software package that computes triangulations of mapping tori of surface homeomorphisms, suitable for Jeff Weeks&#39;s program SnapPea. It consists of two programs. jmt computes triangulations and prints them in a human-readable format. jsnap converts this format into SnapPea&#39;s triangulation file format and may

Emil M. Prodanov

Two classical scalar fields are minimally coupled to gravity in the Kachru-Shulz-Silverstein scenario with a rolling fifth radius. A Tolman wormhole solution is found for a R x S^3 brane with Lorentz metric and for a R x AdS_3 brane with positive definite metric.

Paolo Aschieri

We study electric-magnetic duality rotations for noncommutative electromagnetism (NCEM). We express NCEM as a nonlinear commutative U(1) gauge theory and show that it is self-dual when the noncommutativity parameter θis light-like (e.g. θ^{0i}=θ^{1i}). This implies, in the slowly varying field approximation, self-duality of NCEM to all orders in θ.

S. F. Hassan

We describe a systematic method of studying the action of the T-duality group O(d,d) on space-time fermions and R-R field strengths and potentials in type-II string theories, based on space-time supersymmetry. The formalism is then used to show that the couplings of non-Abelian D-brane charges to R-R potentials can be described by an appropriate Clifford mul

Shijong Ryang

Using the nonabelian Dirac-Born-Infeld action with the Wess-Zumino term that is constructed in consistent with T duality we examine the Myers dielectric effect for multiple D0-branes in the near-horizon geometry of D4-branes. The effect in the curved spacetime is also confirmed by the dual formulation based on the abelian Dirac-Born-Infeld action of a D2-bra

Cumrun Vafa

We show that in the context of topological string theories N branes and M anti-branes give rise to Chern-Simons gauge theory with the gauge supergroup $U(N|M)$. We also identify a deformation of the theory which corresponds to brane/anti-brane annihilation. Furthermore we show that when $N=M$ all open string states are BRST trivial in the deformed theory.

E. J. Ferrer, V. de la Incera, A. Romeo

Symmetry breaking induced by untwisted fermions in QED in a nonsimply connected spacetime with topology $S^{1}\times R^{3}$ is investigated. It is found that the discrete CPT symmetry of the theory is spontaneously broken by the appearance of a constant vacuum expectation value of the electromagnetic potential along the direction of space periodicity. The co

H. Forkel

We investigate the impact of instantons on scalar glueball properties in a largely model-independent analytical approach based on the instanton-improved operator product expansion (IOPE) of the $0^{++}$ glueball correlator. The instanton contributions turn out to be dominant, to substantially improve the consistency of the correponding QCD sum rules, and to

A. Gomez Nicola

We apply the formalism of Chiral Perturbation Theory out of thermal equilibrium to describe explosive production of pions via the parametric resonance mechanism. To lowest order the lagrangian is that of the Nonlinear Sigma Model where the pion decay constant becomes a time-dependent function. This model alows for a consistent nonequilibrium formulation with

Alfred Tang

This paper derives most of the formulas in the MKN (Maung-Kahana-Norbury) Theory of bound states which incorporates the Lande Subtraction method to remove the singularities of the Cornell potential.

F. J. Yndurain

In a recent experimental paper reporting a precise measurement of the muon anomalous magnetic moment, Brown et al. claim disagreement of their result with evaluations based on the standard model. This claim is based on comparison with a single theoretical evaluation. It is pointed out that other equally legitimate theoretical evaluations exist in the literat

Robert R. Caldwell, David Langlois

If our Universe is a three-brane embedded in a five-dimensional anti-deSitter spacetime, in which matter is confined to the brane and gravity inhabits an infinite bulk space, then the causal propagation of luminous and gravitational signals is in general different. A gravitational signal traveling between two points on the brane can take a ``shortcut&#39;&#3

Th. Busch, J. R. Anglin, W. H. Zurek

Superfluid phenomena can be explained in terms of the topologies of the order parameter and of the confining vessel. For example, currents in a toroidal vessel can be characterized by a discrete and conserved quantity, the winding number. In trapped Bose-Einstein condensates, the topology of the trap can be characterized by the topology of the Thomas-Fermi s

C. M. Varma, Z. Nussinov, W. van Saarloos

An introductory survey of the theoretical ideas and calculations and the experimental results which depart from Landau Fermi-liquids is presented. Common themes and possible routes to the singularities leading to the breakdown of Landau Fermi liquids are categorized following an elementary discussion of the theory. Soluble examples of Singular Fermi liquids

R. Chitra, T. Giamarchi, P. Le Doussal

We study the effects of weak disorder on a Wigner crystal in a magnetic field. We show that an elastic description of the pinned Wigner crystal provides an excellent framework to obtain most of the physically relevant observables. Using such a description, we compute the static and dynamical properties. We find that, akin to the Bragg glass phase, a good deg

Rita Claudia Iotti, Fausto Rossi

The first global simulation of semiconductor-based quantum-cascade lasers is presented; Our fully three-dimensional approach allows to study in a purely microscopic way -without resorting to phenomenological parameters- the current-voltage characteristics of state-of-the-art unipolar nanostructures. Based on the proposed theoretical scheme, we are able to gi

C. E. Cunningham, C. Petrovic, G. Lapertot, S. L. Bud&#39;ko

Sintered powders and wires of superconducting $MgB_2$ have been fabricated under a variety of conditions in order to determine details of the diffusion of the $Mg$ into $B$ and to study the types of defects that arise during growth. For samples prepared by exposure of boron to $Mg$ vapor at $950^{\circ}C$, the conversion of particles of less than $100μm$ siz

A. I. Lichtenstein, M. I. Katsnelson

A novel approach to electronic correlations in magnetic crystals which takes into account a dynamical many-body effects is present. In order to to find a frequency dependence of the electron self energy, an effective quantum-impurity many-particle problem need to be solved within the dynamical mean-field theory. The numerically exact QMC-scheme and the spin-

O. A. Yeshchenko, M. M. Biliy, Z. Z. Yanchuk

Low-temperature (1.8 K) excitonic absorption, reflection and photoluminescence spectra of mixed $Zn(P_{1 - x}As_{x})_{2}$ crystals were studied at $x = $0.01, 0.02, 0.03 and 0.05. Energy gap and rydbergs of excitonic B, C and A-series decrease monotonically at the increase of $x$. Spectral half-widths of absorption $n = 1$ lines of B and A-series increase mo

Franck Jedrzejewski

Based on the Tsallis entropy, the nonextensive thermodynamic properties are studied as a q-deformation of classical statistical results using only probabilistic methods and straightforward calculations. It is shown that the constant in the Tsallis entropy depends on the deformation parameter and must be redefined to recover the usual thermodynamic relations.