April 2001 arXiv papers — page 6

Takayuki Hirayama, Gungwon Kang

In the five-dimensional Einstein gravity with negative cosmological constant in the presence/absence of a {\it non-fine-tuned} 3-brane, we have investigated the classical stability of black string solutions which are foliations of four-dimensional $AdS/dS$-Schwarzschild black holes. Such black strings are generically unstable as in the well-known Gregory-Laf

A. Rathgeber, C. Strobl, H. -J. Kutschera, A. Wixforth

The miniaturization and integration of electronic circuitry has not only made the enormous increase in performance of semiconductor devices possible but also spawned a myriad of new products and applications ranging from a cellular phone to a personal computer. Similarly, the miniaturization and integration of chemical and biological processes will revolutio

N. J. MacKay, B. J. Short

We investigate integrable boundary conditions (BCs) for the principal chiral model on the half-line, and rational solutions of the boundary Yang-Baxter equation (BYBE). In each case we find a connection with (type I, Riemannian, globally) symmetric spaces G/H: there is a class of integrable BCs in which the boundary field is restricted to lie in a coset of H

Victor M. Eguiluz, Mogens T. Levinsen, Preben Alstrom

We examine the applicability of the weak wave turbulence theory in explaining experimental scaling results obtained for the diffusion and relative diffusion of particles moving on turbulent surface waves. For capillary waves our theoretical results are shown to be in good agreement with experimental results, where a distinct crossover in diffusive behavior i

Indrajit Mitra, Jose F. Nieves, Palash B. Pal

We calculate the leading order matter-induced corrections to the gravitational interactions of charged leptons and their antiparticles in a medium that contains electrons but not the other charged leptons, such as normal matter. The gravitational coupling, which is universal at the tree level, is found to be flavor-dependent, and also different for the corre

Eric van der Swaluw, Yanqin Wu

We propose a method to infer the initial spin period of pulsars residing in composite supernova remnants. Such a remnant consists of both a plerionic and a shell type component, corresponding respectively to the pulsar wind nebula driven by the spindown luminosity of the central pulsar, and the blastwave bounding the supernova remnant. Theoretical investigat

Carl E. Dolby, Stephen F. Gull

In this paper we apply the concept of radar time (popularised by Bondi in his work on k-calculus) to the well-known relativistic twin `paradox'. Radar time is used to define hypersurfaces of simultaneity for a class of travelling twins, from the `Immediate Turn-around' case, through the `Gradual Turn-around' case, to the `Uniformly Accelerating&#

Amir H. Fatollahi

We consider the dynamics of a charged particle in a space whose coordinates are $N\times N$ hermitian matrices. Putting things in the framework of D0-branes of String Theory, we mention that the transformations of the matrix coordinates induce non-Abelian transformations on the gauge potentials. The Lorentz equations of motion for matrix coordinates are deri

Igor A. Bandos, Jose A. de Azcarraga, Jose M. Izquierdo, Jerzy Lukierski

We describe the coupled system of supergravity and a superbrane source by the sum of the group manifold action for D--dimensional supergravity and the action for a super--$p$--brane. We derive the generalized Einstein equation with the source and discuss the local fermionic symmetries of the coupled action. Our scheme could be especially relevant in $D=11, 1

H. Shen, H. Toki

We extend the quark mean field model to the study of $Λ$ hypernuclei. Without adjusting parameters, the properties of $Λ$ hypernuclei can be described reasonably well. The small spin-orbit splittings for $Λ$ in hypernuclei are achieved, while the $Λ$ single particle energies in the present model are slightly underestimated as compared with the experimental v

Y. Konishi, M. Naka

We study Ricci-flat metrics on non-compact manifolds with the exceptional holonomy $Spin(7), G_2$. We concentrate on the metrics which are defined on ${\bf R} \times G/H$. If the homogeneous coset spaces $G/H$ have weak $G_2$, SU(3) holonomy, the manifold ${\bf R} \times G/H$ may have $Spin(7), G_2$ holonomy metrics. Using the formulation with vector fields,

A. G. Akeroyd, A. Arhrib, M. Capdequi Peyranère

We study the associated production of the A^0 neutral CP-odd Higgs boson with a neutral gauge boson Z in high energy e^+ e^- collisions at the one loop level. We present a detailed discussion for the total cross-section predicted in the context of the Minimal Supersymmetric Standard Model (MSSM) and make a comparison with the non-SUSY Two Higgs Doublet Model

Tanguy Rivoal

We prove that there is at least one irrationnal among the nine numbers zeta(5), zeta(7),..., zeta(21).

Hans Fangohr, Simon J. Cox, Peter A. J. de Groot

We study numerically the dynamics of two-dimensional vortex systems at zero temperature. In addition to pinned states and turbulent plastic flow, we find motion of vortices in rough channels along the direction of the driving force. In this decoupled channel regime we demonstrate how topological defects mediate the phase slip of different channels moving wit

D. G. Cerdeno, E. Gabrielli, S. Khalil, C. Munoz

We analyze the anomalous magnetic moment of the muon (a_μ) in supersymmetric scenarios. First we concentrate on scenarios with universal soft terms. We find that a moderate increase of a_μ can be obtained by lowering the unification scale M_{GUT} to intermediate values 10^{10-12} GeV. However, large values of \tan βare still favored. Then we study the case o

Dirk H. Rischke

I review the extraction of kinetic and chemical freeze-out parameters from experimental data, with particular emphasis on the underlying assumptions and the validity of the conclusions.

Philippe Brax, Jerome Martin, Alain Riazuelo

We study quintessence models using low energy supergravity inspired from string theory. We consider effective supergravity with two scales m_S, the string scale, and m_PL, the Planck scale and show that quintessence naturally arises from a supersymmetry breaking hidden sector. As long as supersymmetry is broken by the $F$-term of a Polonyi-like field coupled

Roberto Emparan, Edward Teo

We study configurations consisting of a pair of non-extremal black holes in four dimensions, both with the same mass, and with charges of the same magnitude but opposite sign---diholes, for short. We present such exact solutions for Einstein-Maxwell theory with arbitrary dilaton coupling, and also solutions to the U(1)^4 theories that arise from compactified

Z. F. Ezawa, K. Hasebe

The Coulomb exchange interaction is the driving force for quantum coherence in quantum Hall systems. We construct a microscopic Landau-site Hamiltonian for the exchange interaction in bilayer quantum Hall ferromagnets, which is characterized by the SU(4) isospin structure. By taking a continuous limit, the Hamiltonian gives rise to the SU(4) nonlinear sigma

Wen-Fa Lu, Chul Koo Kim

For a class of system, the potential of whose Bosonic Hamiltonian has a Fourier representation in the sense of tempered distributions, we calculate the Gaussian effective potential within the framework of functional integral formalism. We show that the Coleman's normal-ordering prescription can be formally generalized to the functional integral formalism

S. Lubeck

We analyse numerically the critical behavior of a conserved lattice gas which was recently introduced as an example of the new universality class of absorbing phase transitions with a conserved field [Phys. Rev. Lett. 85, 1803 (2000)]. We determine the critical exponent of the order parameter as well as the critical exponent of the order parameter fluctuatio

Taichi Itoh, Phillial Oh, Cheol Ryou

We investigate the enlarged CP(N) model in 2+1 dimensions. This is a hybrid of two CP(N) models coupled with each other in a dual symmetric fashion, and it exhibits the gauge symmetry enhancement and radiative induction of the finite off-diagonal gauge boson mass as in the 1+1 dimensional case. We solve the mass gap equations and study the fixed point struct

Andrzej J. Buras, Robert Fleischer

We present a general discussion of the unitarity triangle from $ε_K$, $ΔM_{d,s}$ and $K \to πν\overlineν$ in models with minimal flavour violation (MFV), allowing for arbitrary signs of the generalized Inami--Lim functions $F_{tt}$ and $X$ relevant for $(ε_K,ΔM_{d,s})$ and $K \to πν\overlineν$, respectively. In the models in which $F_{tt}$ has a sign opposit

S. Fajfer, P. Singer, J. Zupan

We present a calculation of the rare decay mode D^0 -> gamma gamma, in which the long distance contributions are expected to be dominant. Using the Heavy Quark Chiral Perturbation Theory Lagrangian with a strong g coupling as recently determined by CLEO from the D^* -> D pi width, we consider both the anomaly contribution which relates to the annihilation pa

Yongseok Oh, H. C. Bhang

We study the vector meson density matrix and the associated polarization asymmetries in $ϕ$ photoproduction near threshold. In order to study the OZI violating processes, we consider the direct $ϕNN$ coupling as well as the knockout processes arising from the non-vanishing $s\bar{s}$ sea quarks in the nucleon. The polarization asymmetries in $ϕ$ meson decays

D. B. Leinweber, A. W. Thomas, K. Tsushima, S. V. Wright

In order to guide the extrapolation of the mass of the rho meson calculated in lattice QCD with dynamical fermions, we study the contributions to its self-energy which vary most rapidly as the quark mass approaches zero; from the processes $ρ\to ωπ$ and $ρ\to ππ$. It turns out that in analysing the most recent data from CP-PACS it is crucial to estimate the

Kentaro Hori, Anton Kapustin

We prove the equivalence of the SL(2,R)/U(1) Kazama-Suzuki model, which is a fermionic generalization of the 2d Black Hole, and N=2 Liouville theory. We show that this duality is an example of mirror symmetry. The essential part of the derivation is to realize the fermionic 2d Black Hole as the low energy limit of a gauged linear sigma-model. Liouville theor

Minfeng Gu, Xinwu Cao, D. R. Jiang

The central black-hole masses of a sample of radio-loud quasars are estimated by using the data of $H_β$ line-width and the optical continuum luminosity. The vast majority of the quasars in this sample have black-hole masses larger than $10^{8} M_{\odot}$, while a few quasars may contain relatively smaller black-holes. We found a significant anti-correlation

Maxim Raginsky, Prem Kumar

We analyze a fiber-optic component which could find multiple uses in novel information-processing systems utilizing squeezed states of light. Our approach is based on the phenomenon of photon-number squeezing of soliton noise after the soliton has propagated through a nonlinear optical fiber. Applications of this component in optical networks for quantum com

L. Accardi, K. Imafuku, S. V. Kozyrev

The stimulated emission from an atom interacting with radiation in non-equilibrium state is considered. The stochastic limit, applied to the non-relativistic Hamiltonian describing the interaction, shows that the state of atoms, driven by some non-equilibrium state of the field approaches a stationary state which can continuously emit photon, unlike the case

L. Accardi, K. Imafuku, S. V. Kozyrev

The interaction of 3-level system with a quantum field in a non-equilibrium state is considered. We describe a class of states of the quantum field for wich a stationary state drives the system to inverse populated state. We find that the quotient of the population of the energy levels in the simplest case is described by the double Einstein formula which in

Simon C. Benjamin

If the interaction between qubits in a quantum computer has a non-diagonal form (e.g. the Heisenberg interaction), then one must be able to "switch it off" in order to prevent uncontrolled propagation of states. Therefore, such QC schemes typically demand local control of the interaction strength between each pair of neighboring qubits. Here we demon

F. Verstraete, A. C. Doherty, H. Mabuchi

We present a general framework for sensitivity optimization in quantum parameter estimation schemes based on continuous (indirect) observation of a dynamical system. As an illustrative example, we analyze the canonical scenario of monitoring the position of a free mass or harmonic oscillator to detect weak classical forces. We show that our framework allows

Gyula Bene

An example is presented when decoherence and quantum interference gives rise to narrow eigenstates (in coordinate representation) for the reduced density matrix of macroscopic quantum systems. On the basis of modal interpretations this means the emergence of classical properties.

Gyula Bene

The relational version of the modal interpretation offers both a consistent quantum ontology and solution for quantum paradoxes within the framework of nonrelativistic quantum mechanics. In the present paper this approach is generalized for the case of relativistic quantum field theories. Physical systems are defined as Hilbert spaces. The concept of the red

Bei Zeng, Xiao Shu Liu, Yan Song Li, Gui Lu Long

Two kinds of $M$-particle d-dimensional cat-like state teleportation protocols are present. In the first protocol, the teleportation is achieved by d-dimensional Bell-basis measurements, while in the second protocol it is realized by d-dimensional GHZ-basis measurement. It is also shown that the second protocol has a simple mathematical formulation that is i

H. C. Rosu

This is the first Internet course on elementary quantum mechanics written in Spanish ("castellano") for the benefit of Spanish speaking students. I thank my eight Mexican students at the Institute of Physics, University of Guanajuato, Leon, (IFUG), for the collaboration that made this possible. The topics included refer to the postulates of quantum m

Raoul Nakhmanson

The examples of "classical teleportation" are done and discussed. Like "quantum ones" they are far away from the science-fiction prototype.

Claudia P. Ferreira, J. F. Fontanari

The requisites for the persistence of small colonies of self-replicating molecules living in a two-dimensional lattice are investigated analytically in the infinite diffusion or mean-field limit and through Monte Carlo simulations in the position-fixed or contact process limit. The molecules are modeled by hipercyclic replicators A which are capable of repli

E. S. Avdeeva

The Lie group of symmetry of the one-dimensional differential equation of electron magnetohydrodynamics with effect of electron inertia and finite conducting is found. It's indicated that this group is group of shift of independent variables and non single-valuety of a potential. Therefore thee no automodel solution except for running vawes.

Laurent Meignin, Patricia Ern, Philippe Gondret, Marc Rabaud

We report experimental results for the Kelvin-Helmholtz instability between two immiscible fluids in parallel flow in a Hele-Shaw cell. We focus our interest on the influence of the gap size between the walls on the instability characteristics. Experimental results show that the instability threshold, the critical wavelength, the phase velocity and the spati

The Cloud Collaboration

This report is the second of two addenda to the CLOUD proposal at CERN (physics/0104048), which aims to test experimentally the existence a link between cosmic rays and cloud formation, and to understand the microphysical mechanism. The document places CLOUD in the framework of a CERN facility for atmospheric research, and provides further details on the par

R. Jauregui

We study the quantum description of parametric heating in harmonic potentials both nonperturbatively and perturbatively, having in mind atom traps. The first approach establishes an explicit connection between classical and quantum descriptions; it also gives analytic expressions for properties such as the width of fractional frequency parametric resonances.

C. Tannous, R. Lahlou, M. Amram

The dispersion relation and mode amplitudes of oblique surface waves propagating on an acoustic double comb filter are obtained with a method based on the calculus of residues. We obtain a better agreement (below 480 Hz) between theoretical predictions and measurements reported previously when the filter was being supposed to be made of a single comb structu

R. Beck, S. N. Cherepnya, L. V. Fil'kov, V. L. Kashevarov

We discuss different interpretations of peaks observed a few years ago by Tatischeff et al. in missing mass spectra of the reaction $pp->pi^+pX$, which were declared as new exited nucleon states with small masses. A study of the possible production of such states in the process $γp->pi^+N^*->pi^+ +γγn$ by analyzing the invariant mass spectrum of $γγn$ is pro

R. Shyam, R. Chatterjee

We review the current status of obtaining the spectroscopic information on the one-neutron halo nuclei from the Coulomb breakup reactions. The theory of these reactions formulated in the framework of the Distorted Wave Born Approximation, allows the use of the realistic wave functions corresponding to any orbital angular momentum structure for the core-valen

H. R. Dullin, M. Horányi, J. E. Howard

We consider the generalized Störmer Problem that includes the electromagnetic and gravitational forces on a charged dust grain near a planet. For dust grains a typical charge to mass ratio is such that neither force can be neglected. Including the gravitational force gives rise to stable circular orbits that encircle that plane entirely above/below the equat

Giuseppe Marmo, Wodzimierz M. Tulczyjew, Pawel Urbanski

We consider a geometric framework for analytical mechanics with external forces. Four versions of this framework are considered. A variational principle with boundary terms and external forces.The second and the third versions are the Lagrangian and Hamiltonian formulations,respectively. The last one is the Poisson formulation. An extensive introductory sect

Sylwia Kondej

We investigate the eigengenvalues problem for self-adjoint operators with the singular perturbations. The general results presented here includes weakly as well as strongly singular cases. We illustrate these results on two models which correspond to so-called additive strongly singular perturbations.

Diogo Aguiar Gomes

In this paper we discuss a stochastic analog of Aubry-Mather theory in which a deterministic control problem is replaced by a controlled diffusion. We prove the existence of a minimizing measure (Mather measure) and discuss its main properties using viscosity solutions of Hamilton-Jacobi equations. Then we prove regularity estimates on viscosity solutions of

Alexander Barvinok, Tamon Stephen

We obtain a number of results regarding the distribution of values of a quadratic function f on the set of nxn permutation matrices (identified with the symmetric group S_n) around its optimum (minimum or maximum). In particular, we estimate the fraction of permutations sigma such that f(sigma) lies within a given neighborhood of the optimal value of f. We i

Masaki Izumi

We extend the notion of the canonical extension of automorphisms of type III factors to the case of endomorphisms with finite statistical dimensions. Following the automorphism case, we introduce two notions for endomorphisms of type III factors: modular endomorphisms and Connes-Takesaki modules. Several applications to compact groups of automorphisms and su

Haisheng Li

A higher dimensional analogue of the notion of vertex algebra is formulated in terms of formal variable language with Borcherds' notion of $G$-vertex algebra as a motivation. Some examples are given and certain analogous duality properties are proved. Furthermore, it is proved that for any vector space $W$, any set of mutually local multi-variable vertex

Michele Mulazzani

In this paper we show that periodic Takahashi 3-manifolds are cyclic coverings of the connected sum of two lens spaces (possibly cyclic coverings of the 3-sphere), branched over knots. When the base space is a 3-sphere, we prove that the associated branching set is a two-bridge knot of genus one, and we determine its type. Moreover, a geometric cyclic presen

H. Lange, E. Sernesi

Let (A,L) be a principally polarized abelian surface of type (1,3). The linear system |L| defines a 6:1 covering of A onto P2, branched along a curve B of degree 18 in P2. The main result of the paper is that for general (A,L) the curve B irreducible, admits 72 cusps, 36 nodes or tacnodes, each tacnode counting as two nodes, 72 flexes and 36 bitangents. The

Ryutaroh Matsumoto, Masakuni Oishi

We propose a decoding method for the generalized algebraic geometry codes proposed by Xing et al. To show its practical usefulness, we give an example of generalized algebraic geometry codes of length 567 over F_8 whose numbers of correctable errors by the proposed method are larger than the shortened codes of the primitive BCH codes of length 4095 in the mo

Makoto Ozawa

We show that any closed incompressible surface in the complement of a positive knot is algebraically non-split from the knot, positive knots cannot bound non-free incompressible Seifert surfaces and that the splitability and the primeness of positive knots and links can be seen from their positive diagrams.

Makoto Ozawa

We show that if a split link is obtained from a split link $L$ in $S^3$ by $1/n$-Dehn surgery along a trivial knot $C$, then the link $L\cup C$ is splittable. That is to say, it is impossible to obtain a split link from a split link via a non-trivial twisting. As its corollary, we completely determine when a trivial link is obtained from a trivial link via a

Thomas Eckl

The existence of a vector field on a compact Kaehler manifold with nonempty zero locus and the properties of this zero locus strongly influence the geometry of the manifold. For example, J. Wahl proved that the existence of a vector field vanishing on an ample divisor of a projective normal variety X implies that X is a cone over this divisor. If X is smooth

Y. Hirata, K. Imai

Lie symmetries for ordinary differential equations are studied. In systems of ordinary differential equations, there do not always exist non-trivial Lie symmetries around equilibrium points. We present a necessary condition for existence of Lie symmetries analytic in the neighbourhood of an equilibrium point. In addition, this result can be applied to a nece

Cristian D. Gonzalez-Aviles

Let X_K be a proper, smooth and geometrically connected curve over a global field K. In this paper we generalize a formula of Milne relating the order of the Tate-Shafarevich group of the Jacobian of X_K to the order of the Brauer group of a proper regular model of X_K. We thereby partially answer a question of Grothendieck.

A. Zabrodin

The integrable structure, recently revealed in some classical problems of the theory of functions in one complex variable, is discussed. Given a simply connected domain in the complex plane, bounded by a simple analytic curve, we consider the conformal mapping problem, the Dirichlet boundary problem, and to the 2D inverse potential problem associated with th

Henrik Thys

Using the quantum double method, we construct a universal R-matrix for the quantization of the Lie superalgebra D(2,1,x). We use this result to construct a link invariant and show it coincides with a specialization of Kauffman's Dubrovnik polynomial.

Bernard de Wit, Martin Rocek, Stefan Vandoren

We extend our previous results on the relation between quaternion-Kahler manifolds and hyperkahler cones and we describe how isometries, moment maps and scalar potentials descend from the cone to the quaternion-Kahler space. As an example of the general construction, we discuss the gauging and the corresponding scalar potential of hypermultiplets with the un

Cesar Gomez

Based on the recently discovered K-theory description of D-branes in string theory a K-theory interpretation of the topology of gauge conditions for four dimensional gauge theories, in particular 't Hooft abelian projection, is presented. The interpretation of the dyon effect in terms of K^{-1} is also discussed. In the context of type IIA strings, D-p b

D. B. Ali, J. A. Gracey

We compute the anomalous dimension of the fermion field with N_f flavours in the fundamental representation of a general Lie colour group in the non-abelian Thirring model at four loops. The implications on the renormalization of the two point Green's function through the loss of multiplicative renormalizability of the model in dimensional regularization

P. Bantay

The theory of permutation orbifolds is reviewed and applied to the study of symmetric product orbifolds and the congruence subgroup problem. The issue of discrete torsion, the combinatorics of symmetric products, the Galois action and questions related to the classification of RCFTs are also discussed.

Cedric Deffayet, Gia Dvali, Gregory Gabadadze, Arthur Lue

We present a model with an infinite volume bulk in which a braneworld with a cosmological constant evolves to a static, 4-dimensional Minkowski spacetime. This evolution occurs for a generic class of initial conditions with positive energy densities. The metric everywhere outside the brane is that of a 5-dimensional Minkowski spacetime, where the effect of t

L. Frankfurt, V. Guzey, M. McDermott, M. Strikman

The nuclear option at THERA provides an ideal and unique opportunity to investigate the black body limit (BBL) of high energy Deep Inelastic Scattering of highly virtual photons off heavy nuclear targets and thereby probe QCD in a new regime. At high enough energies, whichever hadronic configuration the photon fluctuates into, the interaction at a given impa

S. D. Katz

In this thesis two signals pointing beyond the Standard Model are discussed. The first signal is the presence of baryonic matter around us. The possibility of baryogenesis in the Minimal Supersymmetric Standard Model (MSSM) was studied. The bosonic part of the MSSM Lagrangian was put on the lattice. Finite temperature and zero temperature simulations were pe

Kingman Cheung

We study the sensitivity reach of $0.5-2$ TeV $e^+ e^-$ linear colliders in the context of the ADD model, in which gravity becomes strong at TeV scale. We include the real emission channel $e^+ e^- \to γG$, as well as the virtual-graviton-exchange channels $e^+ e^- \to γγ, q\bar q, μ^+μ^-, τ^+ τ^-, e^+ e^-$. Assuming no excess of events over the standard mod

Edward V. Shuryak

Lectures discuss applications of semiclassical methods based on instantons to vacuum structure (chiral symmetry breaking), hadronic structure (various correlation functions), and high energy collisions of hadrons and heavy ions. We discuss phase diagram of hot/dense hadronic matter, and in the last lecture review current puzzles/lesons from the first RHIC ru

A. G. M. Pickering, J. A. Gracey, D. R. T. Jones

We calculate the three loop contribution to the beta-function of the gauge coupling constant in a general, anomaly-free, renormalisable gauge field theory involving a single gauge coupling using the background field method in the MSbar scheme.

Guido Altarelli, Richard D. Ball, Stefano Forte

We review small $x$ contributions to perturbative evolution equations for parton distributions, and their resummation. We emphasize in particular the resummation technique recently developed in order to deal with the apparent instability of naive small $x$ evolution kernels and understand the empirical sucess of fixed--order perturbation theory. We give pred

M. Beccaria, S. Prelovsek, F. M. Renard, C. Verzegnassi

We consider the process of top-antitop production from electron-positron annihilation, for c. m. energies in the few TeV regime, in the MSSM theoretical framework. We show that, at the one loop level, the \underline{slopes} of a number of observable quantities in an energy region around 3 TeV are only dependent on $\tanβ$. Under optimal experimental conditio

M. Buysse

We establish the potential existence of natural relations between the Cabibbo angle and the quark mass ratios, in a Standard Model with one Higgs doublet and two quark generations. The argument is based on the calculation of the divergent one-loop radiative corrections to the quark mass matrices.

A. K. Chaudhuri

We have investigated the effect of viscosity on the gluonic dissociation of $J/ψ$ in an equilibrating plasma. Suppression of $J/ψ$ due to gluonic dissociation depend on the temperature and also on the chemical equilibration rate. In an equilibrating plasma, viscosity affects the temperature evolution and also the chemical equilibration rate, requiring both o

M. Consoli

Quite independently of the Goldstone phenomenon, recent lattice data suggest the existence of gap-less modes in the spontaneously broken phase of a $λΦ^4$ theory. This result is a direct consequence of the quantum nature of the `Higgs condensate' that cannot be treated as a purely classical c-number field.

K. Sato, S. Tsuno, J. Fujimoto, T. Ishikawa

We have successfully developed a technique to integrate an automatic event-generator generation system GRACE and a general-purpose event generator framework PYTHIA. The codes generated by GRACE are embedded in PYTHIA in the created event generator program. The embedded codes give information on parton-level hard interactions directly to PYTHIA. The choice of

Enrico Piotto

The LEP centre of mass energy has been increased since 1996 in the aim of producing the Higgs boson. The SM Higgs boson search has been pursued in the four LEP collaborations exploiting final states with higher branching ratios. In the following we discuss the search in final states with two jets and missing energy or charged leptons.

The KTeV Collaboration, A. Alavi-Harati

We observe 441 K_{L} -> e^{+} e^{-} e^{+} e^{-} candidate events with a background of 4.2 events and measure B(K_{L} -> e^{+} e^{-} e^{+} e^{-}) = (3.72 \pm 0.18(stat) \pm 0.23(syst)) \times 10^{-8} in the KTeV/E799II experiment at Fermilab. Using the distribution of the angle between the planes of the e^{+} e^{-} pairs, we measure the CP parameters beta_{CP

Ernesto Eiroa, Gustavo E. Romero, Diego F. Torres

Chromaticity effects introduced by the finite source size in microlensing events by presumed natural wormholes are studied. It is shown that these effects provide a specific signature that allow to discriminate between ordinary and negative mass lenses through the spectral analysis of the microlensing events. Both galactic and extragalactic situations are di

S. Q. Wu, X. Cai

Source-less wave equations are derived for massless scalar, neutrino and electromagnetic perturbations of a radiating Kerr space-time, and the Hawking radiation of massless particles with spin $s =0, 1/2$ and 1 in this geometry is investigated by using a method of the generalized tortoise coordinate transformation. An extra interaction between the spin of pa

Newton C. A. da Costa, Adonai S. Sant'Anna

We use Padoa's principle of independence of primitive symbols in axiomatic systems in order to discuss the mathematical role of time and space-time in some classical physical theories. We show that time is eliminable in Newtonian mechanics and that space-time is also dispensable in Hamiltonian mechanics, Maxwell's electromagnetic theory, the Dirac el

Z. Y. Zeng, Y. Xiang, L. D. Zhang

We studied theoretically ballistic electronic transport in a proposed mesoscopic structure - Quantum Cable. Our results demonstrated that Qauntum Cable is a unique structure for the study of mesoscopic transport. As a function of Fermi energy, Ballistic conductance exhibits interesting stepwise features. Besides the steps of one or two quantum conductance un

R. Mansilla

A new approach to the understanding of complex behavior of financial markets index using tools from thermodynamics and statistical physics is developed. Physical complexity, a magnitude rooted in Kolmogorov-Chaitin theory is applied to binary sequences built up from real time series of financial markets indexes. The study is based on NASDAQ and Mexican IPC d

Ronald Dickman, Daniel ben-Avraham

We study a one-dimensional lattice random walk with an absorbing boundary at the origin and a movable partial reflector. On encountering the reflector, at site x, the walker is reflected (with probability r) to x-1 and the reflector is simultaneously pushed to x+1. Iteration of the transition matrix, and asymptotic analysis of the probability generating func

Nikolay V. Dokholyan, Eugene I. Shakhnovich

We propose a model that explains the hierarchical organization of proteins in fold families. The model, which is based on the evolutionary selection of proteins by their native state stability, reproduces patterns of amino acids conserved across protein families. Due to its dynamic nature, the model sheds light on the evolutionary time scales. By studying th

D. A. Ryndyk, V. I. Pozdnjakova, I. A. Shereshevskii, N. K. Vdovicheva

We consider dynamics of Josephson vortex lattice in layered superconductors with magnetic, charge (electrostatic) and charge-imbalance (quasiparticle) interactions between interlayer Josephson junctions taken into account. The macroscopic dynamical equations for interlayer Josephson phase differences, intralayer charge and electron-hole imbalance are obtaine

Viviane M. de Oliveira, J. F. Fontanari

The statistical properties of an ecosystem composed of species interacting via pairwise, random interactions and deterministic, concentration limiting self-interaction are studied analytically with tools of equilibrium statistical mechanics of disordered systems. Emphasis is given to the effects of externally induced extinction of a fixed fraction of species

Christoph Jurecka, Verena Gruetzun, Andreas Friedrich, Wolfram Brenig

We demonstrate that a two-triplet resonance strongly renormalizes the Raman spectrum of two-leg spin ladders and moreover suggest this to be the origin of the asymmetry of the magnetic Raman continuum observed in CaV2O5.

Jaroslav Fabian

It is demonstrated on a realistic model of amorphous alloy Si$_{0.9}$Ge$_{0.1}$ with 1000 atoms, that short-range spectral fluctuations of propagons and diffusons are universal and in agreement with random matrix theory. The universality ceases at distances greater than Thouless number $N_T$, where propagons obey the Altshuler-Shklovskii power law, $Σ_2\sim

Z. Y. Zeng, Y. Xiang, L. D. Zhang

We considered the proposed Quantum Cable as a kind of transport spectroscopy of one-dimensional (1D) density of states (DOS) of cylindrical quantum wires. By simultaneously detecting the direct current through the cylindrical quantum wire and the leaked tunneling current into the neighboring wire at desired temperatures, one can obtain detailed information a

Z. Y. Zeng, Y. Xiang, L. D. Zhang

We proposed a model of Quantum Cable in analogy to the recently synthesized coaxial nanocable structure [Suenaga et al. Science, 278, 653 (1997); Zhang et al. ibid, 281, 973 (1998)], and studied its single-electron subband structure. Our results show that the subband spectrum of Quantum Cable is different from either double-quantum-wire (DQW) structure in tw

D. K. Sunko

The parameter regime in which a Brinkmann-Rice (BR) transition appears near half-filling is investigated for a model of of one kind of electrons traversing a plane randomly tiled with CuO_4 molecules, simulating the copper-oxide planes of high-T_c superconductors. As the hole doping is increased, the BR transition evolves continuously into a state characteri

B. Guizal, D. Felbacq, R. Smaali

We study electromagnetic waves scattering by a 2D photonic crystal made of a stack of diffraction gratings. In case where there are only two propagative modes in the crystal, we derive an explicit expression for the superior (resp. inferior) envelope of the reflected (resp. transmitted) energy.

L. Pitaevskii, S. Stringari

The quantum and thermal fluctuations of the phase are investigated in a cold Bose gas confined by a double well trap. The coherence of the system is discussed in terms of the visibility of interference fringes in both momentum and coordinate space. The visibility is calculated at zero as well as at finite temperature. The thermal fluctuations are shown to af

E. Cappelluti, C. Grimaldi, L. Pietronero, S. Strässler

In this paper, through an exhaustive analysis within the Migdal-Eliashberg theory, we show the incompatibility of experimental data of Rb$_3$C$_{60}$ with the basic assumptions of the standard theory of superconductivity. For different models of the electron-phonon spectral function $α^2F(Ω)$ we solve numerically the Eliashberg equations to find which values

Kestutis Staliunas

Statistic dynamics of financial systems is investigated, basing on a model of randomly coupled equation system driven by stochastic Langevin force. It is found that in stable regime the noise power spectrum of the system is of 1/f^alpha form, with the exponent alpha=3/2 in case of Hermitian coupling matrices, or slightly larger (up to 5/3) in nonhermitian ca

E. S. Choi, W. Kang, J. Y. Kim, Min-Seok Park

We have measured temperature dependence of thermoelectric power (TEP) on MgB$_2$ superconductor under hydrostatic pressure. The sign and temperature dependence of TEP shows metallic hole carriers are dominant with activation type contribution at higher temperature. TEP increases with pressure while $T_c$ decrease with ratio -0.136 K/kbar. The data are discus