April 2002 arXiv papers — page 18

Mohammad Kohandel, Michel J. P. Gingras, Josh P. Kemp

Simple symmetry considerations would suggest that the transition from the smectic-A phase to the long-range bond orientationally ordered hexatic smectic-B phase should belong to the XY universality class. However, a number of experimental studies have constantly reported over the past twenty years "novel" critical behavior with non-XY critical expone

R. Gilardi, J. Mesot, A. Drew, U. Divakar

We report here the first direct observations of a well ordered vortex lattice in the bulk of a La(2-x)Sr(x)CuO(4+d) (La214) single crystal (slightly overdoped, x=0.17). Our small angle neutron scattering investigation of the mixed phase reveals a crossover from triangular to square coordination with increasing magnetic field. The existence of an intrinsic sq

Jacco H. Snoeijer, Martin van Hecke, Ellak Somfai, Wim van Saarloos

The effect of boundaries on the force distributions in granular media is illustrated by simulations of 2D packings of frictionless, Hertzian spheres. To elucidate discrepancies between experimental observations and theoretical predictions, we distinguish between the weight distribution {\cal P} (w) measured in experiments and analyzed in the q-model, and the

Sang Koo You, Noboru Fukushima

The efficiency of the variational perturbation theory [Phys. Rev. C {\bf 62}, 045503 (2000)] formulated recently for many-particle systems is examined by calculating the ground state correlation energy of the 3D electron gas with the Coulomb interaction. The perturbation beyond a variational result can be carried out systematically by the modified Wick's

Devaraj van der Meer, Ko van der Weele, Detlef Lohse

Single clusters in a vibro-fluidized granular gas in N connected compartments become unstable at strong shaking. They are experimentally shown to collapse very abruptly. The observed cluster lifetime (as a function of the driving intensity) is analytically calculated within a flux model, making use of the self-similarity of the process. After collapse, the c

S. Denisov, S. Flach, A. A. Ovchinnikov, O. Yevtushenko

We consider low-dimensional dynamical systems exposed to a heat bath and to additional ac fields. The presence of these ac fields may lead to a breaking of certain spatial or temporal symmetries which in turn cause nonzero averages of relevant observables. Nonlinear (non)adiabatic response is employed to explain the effect. We consider a case of a particle i

V. N. Krivoruchko, R. V. Petryuk

The spin-orbit scattering effect on critical current through superconductor/ferromagnet (SF) bilayers separated by an insulator (SFIFS tunnel junction) have been investigated for the case of absence of the superconducting order parameter oscillations (thin F layers). The analysis is based on a microscopic theory for proximity coupled SF bilayer for different

M. H. Szymanska, P. B. Littlewood

We study a model of a photon mode dipole-coupled to a medium of two-level oscillators in a microcavity in the presence of dephasing processes introduced by coupling to external baths. Decoherence processes can be classified as pair-breaking or non-pair-breaking in analogy with magnetic or non-magnetic impurities in superconductors. In the absence of dephasin

P. D. Grigoriev

The Shubnikov - de Haas effect in quasi-two-dimensional normal metals is studied. The interlayer conductivity is calculated using the Kubo formula. The electron scattering on short-range is considered in the self-consistent Born approximation. The result obtained differs from that derived from the Boltzmann transport equation. This difference is shown to be

J. Hemberger, A. Krimmel, T. Kurz, H. -A. Krug von Nidda

We report on structural, magnetic and electrical properties of Sr-doped LaMnO_3 single crystals for doping levels 0.4 < x < 0.85. The complex structural and magnetic phase diagram can only be explained assuming significant contributions from the orbital degrees of freedom. Close to x = 0.6 a ferromagnetic metal is followed by an antiferromagnetic metallic ph

H. W. Diehl, M. Shpot

A two-loop renormalization group analysis of the critical behaviour at an isotropic Lifshitz point is presented. Using dimensional regularization and minimal subtraction of poles, we obtain the expansions of the critical exponents $ν$ and $η$, the crossover exponent $ϕ$, as well as the (related) wave-vector exponent $β_q$, and the correction-to-scaling expon

Eli Livne, Baruch Meerson, Pavel V. Sasorov

Granular hydrodynamics predicts symmetry-breaking instability in a two-dimensional (2D) ensemble of nearly elastically colliding smooth hard spheres driven, at zero gravity, by a rapidly vibrating sidewall. Super- and subcritical symmetry-breaking bifurcations of the simple clustered state are identified, and the supercritical bifurcation curve is computed.

V. Yu. Irkhin, M. I. Katsnelson

Peculiarities of transport properties of three- and two-dimensional half-metallic ferromagnets are investigated, which are connected with the absence of spin-flip scattering processes. The temperature and magnetic field dependences of resistivity in various regimes are calculated. The resistivity is proportional to T^{9/2} for T<T* and to T^{7/2} for T>T*, T

I. Claus, P. Gaspard

In chaotic reaction-diffusion systems with two degrees of freedom, the modes governing the exponential relaxation to the thermodynamic equilibrium present a fractal structure which can be characterized by a Hausdorff dimension. For long wavelength modes, this dimension is related to the Lyapunov exponent and to a reactive diffusion coefficient. This relation

M. Virgilio, P. Grigolini

The aim of this paper is to shed light on the analysis of non-stationary time series by means of the method of diffusion entropy. For this purpose, we first study the case when infinitely many time series, as different realizations of the same dynamic process, are available, so as to adopt the Gibbs ensemble perspective. We solve the problem of establishing

Peter Sheridan Dodds, Joshua S. Weitz

We consider growing spheres seeded by random injection in time and space. Growth stops when two spheres meet leading eventually to a jammed state. We study the statistics of growth limited by packing theoretically in d dimensions and via simulation in d=2, 3, and 4. We show how a broad class of such models exhibit distributions of sphere radii with a univers

Ariel R. Zhitnitsky

We discuss a novel cold dark matter candidate which is formed from the ordinary quarks during the QCD phase transition when the axion domain wall undergoes an unchecked collapse due to the tension in the wall. If a large number of quarks is trapped inside the bulk of a closed axion domain wall, the collapse stops due to the internal Fermi pressure. In this c

Diane B. Paulson, Steven H. Saar, William D. Cochran, Artie P. Hatzes

The Hyades constitute a homogeneous sample of stars ideal for investigating the dependence of planet formation on the mass of the central star. Due to their youth, Hyades members are much more chromospherically active than stars traditionally surveyed for planets using high precision radial velocity (RV) techniques. Therefore, we have conducted a detailed in

William D. Cochran, Artie P. Hatzes, Diane B. Paulson

We describe a high-precision radial velocity search for jovian-mass companions to main sequence stars in the Hyades star cluster. The Hyades provides an extremely well controlled sample of stars of the same age, the same metallicity, and a common birth and early dynamical environment. This sample allows us to explore the dependence of the process of planet f

A. Renzini, C. Cesarsky, S. Cristiani, L. da Costa

Currently public ESO data sets pertinent to the CDFS/GOODS field are briefly illustrated along with an indication on how to get access to them. Future ESO plans for complementing the GOODS database with optical/IR imaging and optical spectroscopy are also described.

Mark Dickinson, Mauro Giavalisco

The Great Observatories Origins Deep Survey (GOODS) is designed to gather the best and deepest multiwavelength data for studying the formation and evolution of galaxies and active galactic nuclei, the distribution of dark and luminous matter at high redshift, the cosmological parameters from distant supernovae, and the extragalactic background light. The pro

J. M. Pittard, I. R. Stevens, P. M. Williams, A. M. T. Pollock

We analyze new high-resolution Chandra X-ray images of the Wolf-Rayet binary system WR147. This system contains a WN8 star with an early-type companion located 0.6&#39;&#39; to its north, and is the only known early-type binary with a separation on the sky large enough for the wind-wind collision between the stars to currently be resolved at X-ray energies.

Janusz A. Gil, George I. Melikidze, Dipanjan Mitra

PSR B0943+10 is known to show remarkably stable drifting subpulses, which can be interpreted in terms of a circumferential motion of 20 sparks, each completing one circulation around the periphery of the polar cap in 37 pulsar periods. We use this observational constraint and argue that the vacuum gap model can adequately describe the observed drift patterns

M. R. Villamariz, A. Herrero, S. R. Becker, K. Butler

We present NLTE abundances of CNO for a sample of four O9 stars in the Galaxy, together with new determinations of their stellar parameters, $T_{\rm eff}$, $\log g$, $ε$(He) and microturbulence. These new analyses take into account the effect of {\it line--blocking} in the spectral synthesis with our classical NLTE, plane--parallel and hydrostatic model atmo

J. M. Diego, E. Martinez-Gonzalez, J. L. Sanz, N. Benitez

The CMB Planck satellite (ESA) will provide a catalogue of nearly 30000 galaxy clusters (Sunyaev-Zel&#39;dovich effect) between redshift 0 and approx. 2-3 (depending on the cosmological model). This hughe catalogue of clusters will allow detailed studies of the evolution of the cluster population with redshift which will constrain the cosmological model. The

N. W. Evans, C. Hunter

A method is developed to evaluate the magnifications of the images of galaxies with lensing potentials stratified on similar concentric ellipses. A simple contour integral is provided which enables the sums of the magnifications of even parity or odd parity or the central image to be easily calculated. The sums for pairs of images vary considerably with sour

K. -H. Kampert, KASCADE-Collaboration

Recent results from the KASCADE extensive air shower experiment are presented. After briefly reviewing the status of the experiment we report on tests of hadronic interaction models and emphasize the progress being made in understanding the properties and origin of the knee at $E_{knee} ~ 4.10^{15} eV. Analysing the muon- and hadron trigger rates in the KASC

Mary K. Gaillard, Joel Giedt

We describe the effective supergravity theory present below the scale of spontaneous gauge symmetry breaking due to an anomalous U(1), obtained by integrating out tree-level interactions of massive modes. A simple case is examined in some detail. We find that the effective theory can be expressed in the linear multiplet formulation, with some interesting con

R. Skip Garibaldi

The Rost invariant associated with a simple simply connected algebraic group G is used to define an invariant of strongly inner forms of G. This invariant takes values in a quotient of H^3(k, Q/Z(2)). It is used to prove a generalization of Gille&#39;s splitting criterion for groups of type E_6 and E_7.

T. M. Tripp, E. B. Jenkins, G. M. Williger, S. R. Heap

Using high S/N STIS echelle spectra (FWHM=7 km/s) of 3C 273, we constrain the metallicities of two Lya clouds in the vicinity of the Virgo cluster. We detect C II, Si II, and Si III absorption lines in the Lya absorber at z = 0.00530. Previous observations with FUSE have revealed Ly beta - Ly theta lines at this redshift, thereby accurately constraining N(H

Ehud Nakar, Tsvi Piran, Jonathan Granot

The realization that GRBs release a constant amount of energy implies that the post jet-break afterglow evolution would be largely universal. For a given redshift all afterglows should be detected up to a fixed observer angle. We estimate the observed magnitude and the implied detectability of orphan afterglows. We show that for reasonable limiting magnitude

Igor A. Shovkovy, Paul J. Ellis

The thermal conductivity of the color-flavor locked phase of dense quark matter is calculated. The dominant contribution to the conductivity comes from photons and Nambu-Goldstone bosons associated with breaking of baryon number which are trapped in the quark core. Because of their very large mean free path the conductivity is also very large. The cooling of

Fredrick Michael, M. D. Johnson

We recently showed that the S&P500 stock market index is well described by Tsallis non-extensive statistics and nonlinear Fokker-Planck time evolution. We argued that these results should be applicable to a broad range of markets and exchanges where anomalous diffusion and `heavy&#39; tails of the distribution are present. In the present work we examine how

Yu Shi

The entanglement between occupation-numbers of different single particle basis states depends on coupling between different single particle basis states in the second-quantized Hamiltonian. Thus in principle, interaction is not necessary for occupation-number entanglement to appear. However, in order to characterize quantum correlation caused by interaction,

Ch. Silberhorn, T. C. Ralph, N. Lütkenhaus, G. Leuchs

We demonstrate that secure quantum key distribution systems based on continuous variables implementations can operate beyond the apparent 3 dB loss limit that is implied by the beam splitting attack . The loss limit was established for standard minimum uncertainty states such as coherent states. We show that by an appropriate postselection mechanism we can e

S. Heinz, R. A. Sunyaev

We propose that relativistic Galactic jets like those observed in GRS 1915+105 and GRO J1655-40 may produce small but measurable contributions to the cosmic ray (CR) spectrum. If these jets contain cold protons and heavy ions (as in SS433), it is plausible that this component will consist of a narrow spectral feature, with a mean particle energy correspondin

S. Sazonov, R. Sunyaev, C. Cramphorn

Only a small fraction of galactic nuclei in the nearby universe are luminous; most of them are currently dim. We investigate the feasibility of constraining the X-ray luminosity in the recent past (up to ~10^6 years ago) of the nucleus of a cluster dominant galaxy by measuring the contribution of scattered radiation from the central source to the surface bri

Daniele Binosi, Joannis Papavassiliou

In this paper we take the first step towards a non-diagrammatic formulation of the Pinch Technique. In particular we proceed into a systematic identification of the parts of the one-loop and two-loop Feynman diagrams that are exchanged during the pinching process in terms of unphysical ghost Green&#39;s functions; the latter appear in the standard Slavnov-Ta

John C. Collins, Xiaomin Zu

In the usual factorization theorems, which give predictions only for inclusive cross sections, there is considerable freedom in the choice of the scheme to define the parton distribution functions. These theorems do not directly apply to Monte-Carlo event generators, and more general factorization theorems which give predictions for fully exclusive cross sec

R. Bennewitz, J. N. Crain, A. Kirakosian, J. -L. Lin

The limits of pushing storage density to the atomic scale are explored with a memory that stores a bit by the presence or absence of one silicon atom. These atoms are positioned at lattice sites along self-assembled tracks with a pitch of 5 atom rows. The writing process involves removal of Si atoms with the tip of a scanning tunneling microscope. The memory

H. Babujian, M. Karowski

Using the results of previous investigations on sine-Gordon form factors exact expressions of all breather matrix elements are obtained for several operators: all powers of the fundamental bose field, general exponentials of it, the energy momentum tensor and all higher currents. Formulae for the asymptotic behavior of bosonic form factors are presented whic

Letizia Stanghellini, Eva Villaver, Arturo Manchado, Martin A. Guerrero

Northern Galactic Planetary nebulae (PNs) are studied to disclose possible correlations between the morphology of the nebulae and the evolution of the central stars (CSs). To this end, we have built the best database available to date, accounting for homogeneity and completeness. We use updated statistical distances, an updated morphological classification s

J. Cannellos, E. J. Ferrer, V. de la Incera

The dispersion relations for leptons in the symmetric phase of the electroweak model in the presence of a constant hypermagnetic field are investigated. The one-loop fermion self-energies are calculated in the lowest Landau level approximation and used to show that the hypermagnetic field forbids the generation of the &#39;&#39;effective mass&#39;&#39; found

Bergfinnur Durhuus, Thordur Jonsson

We prove that there do not exist multisoliton solutions of noncommutative scalar field theory in the Moyal plane which interpolate smoothly between $n$ overlapping solitons and $n$ solitons with an infinite separation.

V. Orlyanchik, A. Vaknin, Z. Ovadyahu, M. Pollak

We study the influence of various excitations on the anomalous field effect observed in insulating indium-oxide films. In conductance G versus gate-voltage Vg measurements one observes a characteristic cusp around the Vg at which the system has equilibrated. In the absence of any disturbance this cusp may persist for a long time after a new gate voltage was

R. M. Serra, C. J. Villas-Boas, N. G. de Almeida, M. H. Y. Moussa

We describe a scheme for the teleportation of entanglements of zero- and one-photon running-wave field states. In addition to linear optical elements, Kerr nonlinearity is also employed so as to achieve a 100% probability of success in the ideal case. A comprehensive phenomenological treatment of errors in the domain of running-wave physics, for linear and n

G. Giachetta, L. Mangiarotti, G. Sardanashvily

A time-dependent completely integrable Hamiltonian system is proved to admit the action-angle coordinates around any regular instantly compact invariant manifold. Written relative to these coordinates, its Hamiltonian and first integrals are functions only of action coordinates.

Ugo Aglietti, Giulia Ricciardi

We present an approximate NNLO evaluation of the QCD form factor resumming large logarithmic perturbative contributions in semi-inclusive heavy flavour decays.

Eric Jeckelmann

The density-matrix renormalization group is used to study the phase diagram of the one-dimensional half-filled Hubbard model with on-site (U) and nearest-neighbor (V) repulsion, and hopping t. A critical line V_c(U) approximately equal to U/2 separates a Mott insulating phase from a charge-density-wave phase. The formation of bound charge excitations for V >

Chai-Yu Lin, Chin-Kun Hu

One important step in the renormalization group (RG) approach to a lattice sandpile model is the exact enumeration of all possible toppling processes of sandpile dynamics inside a cell for RG transformations. Here we propose a computer algorithm to carry out such exact enumeration for cells of planar lattices in RG approach to Bak-Tang-Wiesenfeld sandpile mo

D. M. Ghilencea, S. Groot Nibbelink

A field theory approach to summing threshold effects to the gauge couplings in a two-torus compactification is presented and the link with the (heterotic) string calculation is carefully investigated. We analyse whether the complete UV behaviour of the theory may be described on pure field theory grounds, as due to momentum modes only, and address the role o

Mikhail Z. Iofa

Dyonic black holes with string-loop corrections are studied in the near-horizon region. In perturbative heterotic string theory compactified to four dimensions with N=2 supersymmetry, in the first order in string-loop expansion parameter, we solve the system of Maxwell and Killing spinor equations for dyonic black hole. At the horizon, the string-loop-correc

Yuri Shtanov, Varun Sahni

Higher-dimensional braneworld models which contain both bulk and brane curvature terms in the action admit cosmological singularities of rather unusual form and nature. These `quiescent&#39; singularities, which can occur both during the contracting as well as the expanding phase, are characterised by the fact that while the matter density and Hubble paramet

Bryan Mendez, Marc Davis, John Moustakas, Jeffrey Newman

The properties of the velocity field in the local volume (cz < 550 km/s) have been difficult to constrain due to a lack of a consistent set of galaxy distances. The sparse observations available to date suggest a remarkably quiet flow, with little deviation from a pure Hubble law. However, velocity field models based on the distribution of galaxies in the 1.

Saeed M. Alamoudi, Daniel Boyanovsky, Shang-Yung Wang

We present a field-theoretical method to obtain consistently the equations of motion for small amplitude fluctuations of the order parameter directly in real time for a homogeneous, neutral BCS superconductor. This method allows to study the nonequilibrium relaxation of the order parameter as an initial value problem. We obtain the Ward identities and the ef

O. Miyamura, S. Choe, Y. Liu, T. Takaishi

The responses of quark condensates to the chemical potential, as a function of temperature T and chemical potential μ, are calculated within the Nambu--Jona-Lasinio (NJL) model. We compare our results with those from the recent lattice QCD simulations [QCD-TARO Collaboration, Nucl. Phys. B (Proc. Suppl.) 106, 462 (2002)]. The NJL model and lattice calculatio

Andris Ambainis

We study the class of protocols for weak quantum coin flipping introduced by Spekkens and Rudolph (quant-ph/0202118). We show that, for any protocol in this class, one party can win the coin flip with probability at least $1/\sqrt{2}$.

M. C. de Oliveira, G. J. Milburn

A discrete protocol for teleportation of superpositions of coherent states of optical cavity fields is presented. Displacement and parity operators are unconventionally used in Bell-like measurement for field states.

M. C. de Oliveira, L. F. da Silva, S. S. Mizrahi

We present a protocol to generate and control quantum entanglement between the states of two subsystems (the system ${\cal S}$) by making measurements on a third subsystem (the monitor ${\cal M}$), interacting with ${\cal S}$. For the sake of comparison we consider first an ideal, or instantaneous projective measurement, as postulated by von Neumann. Then we

C. L. Garrido Alzar, L. S. Cruz, J. G. Aguirre Gomez, M. Franca Santos

We have measured the photon statistics of pump and probe beams after interaction with Rb atoms in a situation of Electromagnetically Induced Transparency. Both fields present super-poissonian statistics and their intensities become correlated, in good qualitative agreement with theoretical predictions in which both fields are treated quantum-mechanically. Th

Sahin Kaya Ozdemir, Adam Miranowicz, Masato Koashi, Nobuyuki Imoto

Generation of arbitrary superposition of vacuum and one-photon states using quantum scissors device (QSD) is studied. The device allows the preparation of states by truncating an input coherent light. Optimum values of the intensity of the coherent light for the generation of any desired state using the experimentally feasible QSD scheme are found.

R. C. Woods

This is a discussion of two recent papers by De Aquino [physics/0112081 (2001) and physics/0201058 (2002)] that put forward an explanation of observations of gravity shielding originally reported by Podkletnov and Nieminen [Physica C 203 441 (1992)].

D. F. Escande, Y. Elskens

The rigorous analytical calculation of the diffusion coefficient is performed for the chaotic motion of a particle in a set of longitudinal waves with random phases and large amplitudes (~ A). A first step proves the existence of a quasilinear diffusion on a time scale ~ A^{-2/3} \ln A. A second step uses this property to extend the result to asymptotic time

Philip R. Page

We review the status of hybrid baryons. The only known way to study hybrids rigorously is via excited adiabatic potentials. Hybrids can be modelled by both the bag and flux-tube models. The low-lying hybrid baryon is N 1/2^+ with a mass of 1.5-1.8 GeV. Hybrid baryons can be produced in the glue-rich processes of diffractive gamma N and pi N production, Psi d

Jerome Margueron, Jesus Navarro, Van Giai Nguyen

The stability of the equation of state predicted by Skyrme-type interactions is examined. We consider simultaneously symmetric nuclear matter and pure neutron matter. The stability is defined by the inequalities that the Landau parameters must satisfy simultaneously. A systematic study is carried out to define interaction parameter domains where the inequali

Pasi Huovinen

The hydrodynamical models used to describe the evolution of heavy-ion collisions are briefly reviewed and their results compared with recent RHIC data.

K. Adcox, PHENIX Collaboration

Two particle azimuthal correlation functions are presented for charged hadrons produced in Au + Au collisions at RHIC sqrt(s_NN) = 130 GeV. The measurements permit determination of elliptic flow without event-by-event estimation of the reaction plane. The extracted elliptic flow values v_2 show significant sensitivity to both the collision centrality and the

R. Festa, A. Mazzino, D. Vincenzi

The Lorenz 1963 dynamical system is known to reduce in the steady state to a one-dimensional motion of a classical particle subjected to viscous damping in a past history-dependent potential field. If the potential field is substituted by a periodic function of the position, the resulting system shows a rich dynamics where (standard) diffusive behaviours, ba

Ricardo Lopez-Ruiz, Amalio F. Pacheco

We analyze the frictionless motion of a point-like particle that slides under gravity on an inverted conical surface. This motion is studied for arbitrary initial conditions and a general relation, valid within 13%, between the periods of radial and angular oscillations, that holds for both small and high energy trajectories, is obtained. This relation allow

Heng Chun Hu, Q. P. Liu

A new Darboux transformation is presented for the Hirota-Satsuma coupled KdV system. It is shown that this Darboux transformation can be constructed by means of two methods: Painlevé analysis and reduction of a binary Darboux transformation. By iteration of the Darboux transformation, the Grammian type solutions are found for the coupled KdV system.

Asish Ganguly

We propose a new approach based on the algebraization of the Associated Lamé equation \[-ψ&#39;&#39;(x) + [ m(m+1)k^{2}sn^{2}x + \ell(\ell+1)k^{2}(cn^{2}x/dn^{2}x)]ψ(x) = Eψ(x)\] within sl(2,R) to derive the corresponding periodic potentials. The band edge eigenfunctions and energy spectra are explicitly obtained for integers m,$\ell$. We also obtain the exp

Wifredo Garcia Fuertes, Askold Perelomov

We compute the generating function for the characters of the irreducible representations of SU(n) whose associated Young diagrams have only two rows with the same number of boxes. The result is a rational determinantal expression in which both the numerator and the denominator have a simple structure when expressed in terms of Schur polynomials.

J. Coussement, A. B. J. Kuijlaars, W. Van Assche

We introduce a spectral transform for the finite relativistic Toda lattice (RTL) in generalized form. In the nonrelativistic case, Moser constructed a spectral transform from the spectral theory of symmetric Jacobi matrices. Here we use a non-symmetric generalized eigenvalue problem for a pair of bidiagonal matrices (L,M) to define the spectral transform for

Juan-Pablo Ortega

During the last thirty years, symplectic or Marsden--Weinstein reduction has been a major tool in the construction of new symplectic manifolds and in the study of mechanical systems with symmetry. This procedure has been traditionally associated to the canonical action of a Lie group on a symplectic manifold, in the presence of a momentum map. In this note w

Yves Felix, Jean-Claude Thomas

Let M be a simply-connected closed oriented N-dimensional manifold. We prove that for any field of coefficients there exists a natural homomorphism of commutative graded algebras $Ψ: H_\ast (Ω{aut}_1 M) \to H_{\ast +N}(M^{S^1})$ where $H_\ast (M^{S^1})$ is the loop algebra defined by Chas-Sullivan. As usual ${aut}_1 X$ (resp. $ΩX$) denotes the monoid of the

Michael Farber

In this paper we study a new topological invariant $\Cat(X,ξ)$, where $X$ is a finite polyhedron and $ξ\in H^1(X;\R)$ is a real cohomology class. $\Cat(X,ξ)$ is defined using open covers of $X$ with certain geometric properties; it is a generalization of the classical Lusternik -- Schnirelman category. We show that $\Cat(X,ξ)$ depends only on the homotopy ty

M. Ahmed, J. De Loera, R. Hemmecke

Using computational algebraic geometry techniques and Hilbert bases of polyhedral cones we derive explicit formulas and generating functions for the number of magic squares and magic cubes.

D. Kotschick, T. Vogel

We generalise the average asymptotic linking number of a pair of divergence-free vector fields on homology three-spheres by considering the linking of a divergence-free vector field on a manifold of arbitrary dimension with a codimension two foliation endowed with an invariant transverse measure. We prove that the average asymptotic linking number is given b

Marco Manetti

We prove that for every compact Kähler manifold $X$ there exists an $L$-infinity morphism, lifting the usual cup product in cohomology, from the Kodaira-Spencer differential graded Lie algebra to the suspension of the space of linear endomorphisms of the singular cohomology of $X$. As a consequence we get an algebraic proof of the principle ``obstructions to

Annette Werner

Inspired by Manin&#39;s approach towards a geometric interpretation of Arakelov theory at infinity, we interpret in this paper non-Archimedean local intersection numbers of linear cycles in $P^{n-1}$ with the combinatorial geometry of the Bruhat-Tits building associated to PGL(n).

A. D. Alhaidari

This combines a reply to the Comment [hep-th/0203067 v1] by A. N. Vaidya and R. de L. Rodrigues with an erratum to our Letter [Phys. Rev. Lett. 87, 210405 (2001)]

Anna S. Kotanjyan, Aram A. Saharian

The emitted power of the radiation from a charged particle moving uniformly on a circle inside a cylindrical waveguide is considered. The expressions for the energy flux of the radiation passing through the waveguide cross-section are derived for both TE and TM waves. The results of the numerical evaluation are presented for the number of emitted quanta depe

J. Fernando Barbero, Eduardo J. S. Villaseñor

We study the physical content of quadratic diff-invariant Lagrangians in arbitrary dimensions by using covariant symplectic techniques. This paper extends previous results in dimension four. We discuss the difference between the even and odd dimensional cases.

R. Rapp

The consequences of hadro-chemical freezeout for the subsequent hadron gas evolution in central heavy-ion collisions at RHIC and LHC energies are discussed with special emphasis on effects due to antibaryons. Contrary to naive expectations, their individual conservation, as implied by experimental data, has significant impact on the chemical off-equilibrium

E. O. Iltan

We study the new structures appearing due to noncommutative effects in the inclusive decay b -> s γ^*, in the standard model. We present the corresponding coefficients which carries the space-space and space-time noncommutativity.

Kei Iida, Gordon Baym

We study, within Ginzburg-Landau theory, the responses of three-flavor superfluid quark-gluon plasmas to external magnetic fields and rotation, in both the color-flavor locked and isoscalar color-antitriplet diquark phases near the critical temperature. Fields are incorporated in the gradient energy arising from long wavelength distortions of the condensate,

S. Moretti, K. Odagiri, P. Richardson, M. H. Seymour

We describe the implementation of supersymmetric processes in the HERWIG Monte Carlo event generator. We define relevant parameter and mixing conventions and list the hard scattering matrix elements. Our implementation is based on the Minimum Supersymmetric Standard Model, with the option of R-parity violation. The sparticle spectrum is completely general. B

N. Nakajima, H. Matsufuru, Y. Nemoto, H. Suganuma

The spectra of octet and decuplet baryons are studied using SU(3) lattice QCD at the quenched level. As an implementation to reduce the statistical fluctuation, we employ the anisotropic lattice with $O(a)$ improved quark action. In relation to $Λ(1405)$, we measure also the mass of the SU(3) flavor-singlet negative-parity baryon, which is described as a thr

Sabine W Lammers

Asymmetric jet transverse energy cuts are now commonly used for dijet analyses currently performed in the Breit Frame at ZEUS. I will discuss the motivation for these cuts and present the results of studies identifying unphysical behavior in the theroretically calculated dijet cross section when purely symmetric cuts are used.

Eneko Agirre, David Martinez

Selectional preference learning methods have usually focused on word-to-class relations, e.g., a verb selects as its subject a given nominal class. This paper extends previous statistical models to class-to-class preferences, and presents a model that learns selectional preferences for classes of verbs, together with an algorithm to integrate the learned pre

Steve Cassidy, Steven Bird

Annotated speech corpora are databases consisting of signal data along with time-aligned symbolic `transcriptions&#39;. Such databases are typically multidimensional, heterogeneous and dynamic. These properties present a number of tough challenges for representation and query. The temporal nature of the data adds an additional layer of complexity. This paper

Steven Bird

Phonology is the systematic study of the sounds used in language, their internal structure, and their composition into syllables, words and phrases. Computational phonology is the application of formal and computational techniques to the representation and processing of phonological information. This chapter will present the fundamentals of descriptive phono

Nguyen Quoc Hung, Dinh Quoc Vuong, Nguyen Quang Bau

Based on the quantum transport equation for the electron-phonon system, the absorption coefficient of sound (acoustic phonons) by absorption of a laser radiation in quantum wires with parabolic potential is calculated for the case of monophoton absorption and the case of multiphoton absorption. Analytical expressions and conditions for the absorption coeffic

E. Tutuc, E. P. De Poortere, S. J. Papadakis, M. Shayegan

We have made quantitative measurements of the spin polarization of two-dimensional (2D) GaAs (100) electrons and GaAs (311)A holes, as a function of an in-plane magnetic field. The functional form of the in-plane magnetoresistance is shown to be intimately related to the spin polarization. Moreover, for three different 2D systems, namely GaAs (100) electrons

A. Tanguy, J. P. Wittmer, F. Leonforte, J. -L. Barrat

The approach of the elastic continuum limit in small amorphous bodies formed by weakly polydisperse Lennard-Jones beads is investigated in a systematic finite-size study. We show that classical continuum elasticity breaks down when the wavelength of the sollicitation is smaller than a characteristic length of approximately 30 molecular sizes. Due to this sur

M. A. H. Vozmediano, J. Gonzalez, F. Guinea, J. V. Alvarez

The Fermi surface of most hole-doped cuprates is close to a Van Hove singularity at the M point. A two-dimensional electronic system, whose Fermi surface is close to a Van Hove singularity shows a variety of weak coupling instabilities. It is a convenient model to study the interplay between antiferromagnetism and anisotropic superconductivity. The renormali

Manuel Valin-Rodriguez, Antonio Puente, Llorens Serra

We investigate the relevance of the spin-orit coupling to the far-infrared absorption of two-dimensional semiconductor dots. Varying the strength of the Dresselhaus term, a mechanism feasible in experiment by changing the dot width, distinctive splittings of the Kohn peak as well as additional low energy modes are predicted in a non-interacting model. Each m

F. Leyvraz, M. -C. Firpo, S. Ruffo

The system of N particles moving on a circle and interacting via a global repulsive cosine interaction is well known to display spatially inhomogeneous structures of extraordinary stability starting from certain low energy initial conditions. The object of this paper is to show in a detailed manner how these structures arise and to explain their stability. B

P. Wiegmann

The shape of an electronic droplet in the quantum Hall effect is sensitive to gradients of the magnetic field, even if they are placed outside the droplet. Magnetic impurities cause a fingering instability of the edge of the droplet, similar to the Saffman-Taylor fingering instability of an interface between two immiscible phases. We discuss the fingering in

B. M. T. Goncalves, J. F. F. Mendes

We have studied the island size distribution and spatial correlation function of an island growth model under the effect of an elastic interaction of the form $1/r^{3}$. The mass distribution $P_n(t)$ that was obtained presents a pronounced peak that widens with the increase of the total coverage of the system, $θ$. The presence of this peak is an indication