March 2002 arXiv papers — page 21

A. S. Kapoyannis

The evolution of a hadronic system after its chemical decomposition is described through a model that conserves the hadronic multiplicities to their values at chemical freeze-out. The state of the system is found as function of temperature and the corresponding baryon density is evaluated. The baryon density at thermal decoupling is also computed.

G. Bonvicini, A. Schreiner

A Time Projection Chamber (TPC) is one of the promising candidates to perform unique measurements in solar neutrino physics. Its features will enable it to work at depths of the order of 2000 mwe. This paper describes an estimation of the expected cosmogenic background at different depths including also the background due to fission activation of the TPC mat

M. Baylac, E. Burtin, C. Cavata, S. Escoffier

A Compton polarimeter has been installed in Hall A at Jefferson Laboratory. This letter reports on the first electron beam polarization measurements performed during the HAPPEX experiment at an electron energy of 3.3 GeV and an average current of 40 $μ$A. The heart of this device is a Fabry-Perot cavity which increased the luminosity for Compton scattering i

H1 Collaboration, C. Adloff

Dijet events in photon-proton collisions in which there is a large pseudorapidity separation Delta eta > 2.5 between the two highest E_T jets are studied with the H1 detector at HERA. The inclusive dijet cross sections are measured as functions of the longitudinal momentum fractions of the proton and photon which participate in the production of the jets, x_

S. E. Middleton, D. C. De Roure, N. R. Shadbolt

Tools for filtering the World Wide Web exist, but they are hampered by the difficulty of capturing user preferences in such a dynamic environment. We explore the acquisition of user profiles by unobtrusive monitoring of browsing behaviour and application of supervised machine-learning techniques coupled with an ontological representation to extract user pref

Chinlin Guo, Herbert Levine, David A. Kessler

Protein amyloidosis is a cytopathological process characterized by the formation of highly beta-sheet-rich fibrils. How this process occurs and how to prevent/treat the associated diseases are not completely understood. Here, we carry out a theoretical investigation of sequence-independent beta-sheet formation, based on recent findings regarding the cooperat

Marvin D. Girardeau, Kunal K. Das, Ewan M. Wright

The dynamics of an atom waveguide X-junction beam splitter becomes truly 1D in a regime of low temperatures and densities and large positive scattering lengths where the transverse mode becomes frozen and the many-body Schrodinger dynamics becomes exactly soluble via a generalized Fermi-Bose mapping theorem. We analyze the interferometric response of a doubl

Sudhansu S. Mandal, T. V. Ramakrishnan

We show in a realistic $d_{x^{2}-y^{2}}$ symmetry gap model for a cuprate superconductor that the clean vortex lattice has discontinuous structural transitions (at and near T=0), as a function of the magnetic field $B$ along the c-axis. The transitions arise from the singular nonlocal and anisotropic susceptibility of the $d_{x^{2}-y^{2}}$ superconductor to

C. L. Zhang, X. J. Chen, C. C. Almasan, J. S. Gardner

The temperature $T$ and magnetic field $H$ dependence of anisotropic in-plane $ρ_{ab}$ and out-of-plane $ρ_{c}$ resistivities have been investigated in single crystals of the bilayer manganite La$_{1.2}$Sr$_{1.8}$Mn$_{2}$O$_{7}$. Below the Curie transition temperature $T_c=$ 125 K, $ρ_{ab}$ and $ρ_{c}$ display almost the same temperature dependence with an u

X. J. Chen, S. Soltan, H. Zhang, H. -U. Habermeier

We report on a systematic study of strain effects on the transport properties and the ferromagnetic transition temperature $T_{c}$ of high-quality La$_{0.9}$Sr$_{0.1}$MnO$_{3}$ thin films epitaxially grown on (100) SrTiO$_{3}$ substrates. Both the magnetization and the resistivity are critically dependent on the film thickness. $T_{c}$ is enhanced with decre

X. J. Chen, H. Zhang, H. -U. Habermeier

We discuss the effects of hydrostatic pressure on the superconducting properties of MgB$_{2}$ within the framework of Eliashberg theory. By considering the pressure dependences of all parameters appearing in the McMillan formula, we show that the calculated pressure derivative of $T_{c}$ as well as the variation of $T_{c}$ with pressure are in good agreement

R. Dobrin, J. H. Meinke, P. M. Duxbury

We present exact results for the critical behavior of the RFIM on complete graphs and trees, both at equilibrium and away from equilibrium, i.e., models for hysteresis and Barkhausen noise. We show that for stretched exponential and power law distributions of random fields the behavior on complete graphs is non-universal, while the behavior on Cayley trees i

J. Stockburger, H. Grabert

The reduced dynamics of a quantum system interacting with a linear heat bath finds an exact representation in terms of a stochastic Schr{ö}dinger equation. All memory effects of the reservoir are transformed into noise correlations and mean-field friction. The classical limit of the resulting stochastic dynamics is shown to be a generalized Langevin equation

Young C. Kim, Mikhail A. Anisimov, Jan V. Sengers, Erik Luijten

The character of critical behavior in physical systems depends on the range of interactions. In the limit of infinite range of the interactions, systems will exhibit mean-field critical behavior, i.e., critical behavior not affected by fluctuations of the order parameter. If the interaction range is finite, the critical behavior asymptotically close to the c

Igor S. Aranson, Lev S. Tsimring

In the framework of the theory of partially fluidized granular flows we study the formation of longitudinal structures observed experimentally by Forterre and Pouliquen in a flow down a rough inclined plane. We show that the formation of longitudinal structures is related to the positive feedback between the fluidization rate and the lateral stress (side pre

P. Samuelsson, M. Buttiker

As an electrical analog of the optical Hanbury Brown Twiss effect, we study current cross-correlations in a chaotic quantum dot-superconductor junction. One superconducting and two normal reservoirs are connected via point contacts to a chaotic quantum dot. For a wide range of contact widths and transparencies, we find large positive current correlations. Th

P. Bourges, Y. Sidis, M. Braden, K. Nakajima

We have mapped out the spin dynamics in a stripe-ordered nickelate, La$_{2-x}$Sr$_{x}$NiO$_{4}$ with $x \simeq 0.31$, using inelastic neutron scattering. We observe spin-wave excitations up to 80 meV emerging from the incommensurate magnetic peaks with an almost isotropic spin-velocity: $\hbar c_s\sim 0.32$ eV Å, very similar to the velocity in the undoped,

S. Anantha Ramakrishna, A. M. Jayannavar

We derive an expression for the conditional time for the reflection of a wave from an arbitrary potential barrier using the WKB wavefunction in the barrier region. Our result indicates that the conditional times for transmission and reflection are equal for a symmetric barrier within the validity of the WKB approach.

I. Spagnolatti, M. Bernasconi, G. Benedek

The electron-phonon coupling of a theoretically devised carbon phase made by assembling the smallest fullerenes C$_{20}$ is calculated from first principles. The structure consists of C$_{20}$ cages in an {\it fcc} lattice interlinked by two bridging carbon atoms in the interstitial tetrahedral sites ({\it fcc}-C$_{22}$). The crystal is insulating but can be

M. Krawiec, B. L. Gyorffy, J. F. Annett

We study a simple microscopic model for thin, ferromagnetic, metallic layers on semi-infinite bulk superconductor. We find that for certain values of the exchange spliting, on the ferromagnetic side, the ground states of such structures feature spontaneously induced spin polarized currents. Using a mean-field theory, which is selfconsistent with respect to t

Eva Majernikova, J. Riedel, S. Shpyrko

The ground state polaron potential of 1D lattice of two-level molecules with spinless electrons and two Einstein phonon modes with quantum phonon-assisted transitions between the levels is found anharmonic in phonon displacements. The potential shows a crossover from two nonequivalent broad minima to a single narrow minimum corresponding to the level positio

Zenji Hiroi, Jun-Ichi Yamaura, Yuji Muraoka, Masafumi Hanawa

Evidence for another phase transition at 120 K in the metallic pyrochlore oxide Cd2Re2O7, following the structural transition at 200 K and followed by the superconducting transition at 1.0 K, is given through resistivity, magnetoresistance, specific heat, and X-ray diffraction measurements. The results indicate unique successive structural and electronic tra

H. Hong, M. Y. Choi, Beom Jun Kim

We investigate global phase coherence in a system of coupled oscillators on a small-world networks constructed from a ring with nearest-neighbor edges. The effects of both thermal noise and quenched randomness on phase ordering are examined and compared with the global coherence in the corresponding \xy model without quenched randomness. It is found that in

Boris Kastening

We considerably simplify Kaufman's solution of the two-dimensional Ising model by introducing two commuting representations of the complex rotation group SO(2n,C). All eigenvalues of the transfer matrix and therefore the partition function are found in a straightforward way.

Silvia Torres-Peimbert, Manuel Peimbert

It is argued that an important fraction of PNe present large temperature variations that are not due to observational errors nor to incomplete atomic physics. Seven possible causes for these variations are reviewed, one of them is presented for the first time.

Travis S. Barman, Peter H. Hauschildt, Andreas Schweitzer, Phillip C. Stancil

The recent announcement that sodium absorption has been observed in the atmosphere of HD209458b, the only EGP observed to transit its parent star, is the first direct detection of an EGP atmosphere. We explore the possibility that neutral sodium is {\em not} in local thermodynamic equilibrium (LTE) in the outer atmosphere of irradiated EGPs and that the sodi

James D. Neill, Michael M. Shara, Adeline Caulet, David A. H. Buckley

We report the first orbital period determination for a Dwarf Nova (DN) in a glubular cluster: V101 in M5 has a period of 5.796 +- 0.036 hours. We derived this period from I-band photometry acquired with the Calypso Observatory High Resolution Camera operating with tip-tilt adaptive optics correction. Observations from the South African Astronomical Observato

Orsola De Marco, Geoffrey C. Clayton, F. Herwig, D. L. Pollacco

We investigate the evolutionary status of four stars: V348 Sgr, DY Cen and MV Sgr in the Galaxy and HV 2671 in the LMC. These stars have in common random deep declines in visual brightness which are characteristic for R Coronae Borealis (RCB) stars. RCB stars are typically cool, hydrogen deficient supergiants. The four stars studied in this paper are hotter

J. M. Stil, F. P. Israel

This paper is the second in a series presenting a sample of 29 late-type dwarf galaxies observed with the Westerbork Synthesis Radio Telescope in the 21-cm line of neutral hydrogen (HI). Here we present rotation curves, maps of the velocity field and maps of the velocity dispersion across the sample galaxies.

M. Cervino

In this contribution I present my current work in a new generation of evolutionary synthesis models that compute the multiwavelength energy distribution (from gamma-rays to radio) as well as the associated dispersion for young stellar systems. I will also show some statistical effects that may appear in the analysis of surveys, like bimodal or multi-modal di

Tyler E. Nordgren, B. F. Lane, R. B. Hindsley, P. Kervella

Direct diameter observations of Cepheid variables are used to calibrate the Barnes-Evans Cepheid surface brightness relation. Fifty-nine separate Cepheid diameter measurements from four different optical interferometers are used to calculate surface brightnesses as a function of magnitude and color. The linear fit to Cepheid surface brightness versus color i

J. M. Stil, F. P. Israel

This paper is the first in a series presenting a sample of 29 late-type dwarf galaxies, observed with the Westerbork Synthesis Radio Telescope (WSRT) in the 21-cm line of neutral atomic hydrogen (HI). The sample itself, the HI content of and the HI distribution in the sample galaxies are briefly discussed. Four sample galaxies were also detected in the conti

M. Steffen, H. Holweger

In an effort to estimate the largely unknown effects of photospheric temperature fluctuations on spectroscopic abundance determinations, we have studied the problem of LTE line formation in the inhomogeneous solar photosphere based on detailed 2-dimensional radiation hydrodynamics simulations of the convective surface layers of the Sun. By means of a strictl

M. Kramer, S. Johnston, W. van Straten

We present high-resolution multi-frequency single-pulse observations of the Vela pulsar, PSR B0833-45, aimed at studying micro-structure, phase-resolved intensity fluctuations and energy distributions at 1.41 and 2.30 GHz. We show that the micro-pulse width in pulsars has a period dependence. Like individual pulses, Vela's micro-pulses are highly ellipti

Malcolm P. Kennett, Mona Berciu, R. N. Bhatt

We report the results of a Monte Carlo study of a model of (III,Mn)V diluted magnetic semiconductors which uses an impurity band description of carriers coupled to localized Mn spins and is applicable for carrier densities below and around the metal-insulator transition. In agreement with mean field studies, we find a transition to a ferromagnetic phase at l

Christopher T. Hill, Elizabeth H. Simmons

The breaking of the electroweak symmetry, and origin of the associated ``weak scale,'' may be due to a new strong interaction. Theoretical developments over the past decade have led to viable models and mechanisms that are consistent with current experimental data. Many of these schemes feature a privileged role for the top quark, and third generatio

Artur B. Adib, Marcelo Gleiser, Carlos A. S. Almeida

The possibility that extremely long-lived, time-dependent, and localized field configurations (``oscillons'') arise during the collapse of asymmetrical bubbles in 2+1 dimensional phi^4 models is investigated. It is found that oscillons can develop from a large spectrum of elliptically deformed bubbles. Moreover, we provide numerical evidence that suc

Stuart Wyithe, Abraham Loeb

Exceptionally bright quasars with redshifts up to z=6.28 have recently been discovered. Quasars are thought to be powered by the accretion of gas onto supermassive black holes at the centres of galaxies. Their maximum (Eddington) luminosity is proportional to the mass of the black hole, and so these bright quasars are inferred to have black holes with masses

P. Matlock, R. C. Rashkov, K. S. Viswanathan, Y. Yang

We consider tachyonic string-field fluctuations about a Dp-brane background in the geometrical (CFT) formulation of Vacuum String Field Theory. We then extend this analysis to the case of a background B-field. We find that the standard results for D-brane tension are reproduced in both cases.

Pierre Henry-Labordere, Bernard Julia, Louis Paulot

It is well known but rather mysterious that root spaces of the $E_k$ Lie groups appear in the second integral cohomology of regular, complex, compact, del Pezzo surfaces. The corresponding groups act on the scalar fields (0-forms) of toroidal compactifications of M theory. Their Borel subgroups are actually subgroups of supergroups of finite dimension over t

Vivien M Kendon, Karol Zyczkowski, William J Munro

The entanglement in a pure state of N qudits (d-dimensional distinguishable quantum particles) can be characterised by specifying how entangled its subsystems are. A generally mixed subsystem of m qudits is obtained by tracing over the other N-m qudits. We examine the entanglement in the space of mixed states of m qudits. We show that for a typical pure stat

M. Cristina Marchetti, Karin A. Dahmen

We study the dynamics of a viscoelastic medium driven through quenched disorder by expanding about mean field theory in $6-ε$ dimensions. The model exhibits a critical point separating a region where the dynamics is hysteretic with a macroscopic jump between strongly pinned and weakly pinned states, from a region where the sliding state is unique and no jump

Christopher J. Fewster, Rainer Verch

Quantum weak energy inequalities have recently been extensively discussed as a condition on the dynamical stability of quantum field states, particularly on curved spacetimes. We formulate the notion of a quantum weak energy inequality for general dynamical systems on static background spacetimes and establish a connection between quantum weak energy inequal

Shyamoli Chaudhuri

An ensemble of short open strings in equilibrium with the heat bath provided by the Euclidean worldvolume of a stack of Dbranes undergoes a thermal phase transition to a long string phase. The transition temperature is just below the string scale. We point out that this phenomenon provides a simple mechanism within open and closed string theories for alterin

J. Kim, P. L. Krapivsky, B. Kahng, S. Redner

We investigate a model protein interaction network whose links represent interactions between individual proteins. This network evolves by the functional duplication of proteins, supplemented by random link addition to account for mutations. When link addition is dominant, an infinite-order percolation transition arises as a function of the addition rate. In

G. Ecker, R. Unterdorfer

We calculate the processes e+ e- -> 4 pions and tau -> nu_tau + 4 pions to O(p^4) in the low-energy expansion of the standard model. The chiral amplitudes of O(p^4) can be extended via resonance exchange to energies around 1 GeV. Higher-order effects have been included in the form of omega, a_1 and double rho exchange and by performing a resummation of the p

G. Kälbermann

We depict and analyze a new effect for wavepackets falling freely under a barrier or well. The effect appears for wavepackets whose initial spread is smaller than the combination $\ds \sqrt{\frac{l_g^3}{|z_0|}}$, between the gravitational length scale $\ds l_g = \frac{1}{(2 m^2 g)^{1/3}}$ and the initial location of the packet $z_0$. It consists of a diffrac

E. A. De Wolf

We discuss basic concepts and properties of diffractive phenomena in soft hadron collisions and in deep-inelastic scattering at low Bjorken-x. The paper is not a review of the rapidly developing field but presents an attempt to show in simple terms the close inter-relationship between the dynamics of high-energy hadronic and deep-inelastic diffraction. Using

M. Bertolini, T. Harmark, N. A. Obers, A. Westerberg

We construct non-extremal fractional D-brane solutions of type-II string theory at the Z_2 orbifold point of K3. These solutions generalize known extremal fractional-brane solutions and provide further insights into N=2 supersymmetric gauge theories and dual descriptions thereof. In particular, we find that for these solutions the horizon radius cannot excee

V. L. Gurevich, D. A. Parshin, H. R. Schober

We show that a {\em vibrational instability} of the spectrum of weakly interacting quasi-local harmonic modes creates the maximum in the inelastic scattering intensity in glasses, the Boson peak. The instability, limited by anharmonicity, causes a complete reconstruction of the vibrational density of states (DOS) below some frequency $ω_c$, proportional to t

N. Aghanim, P. G. Castro, A. Melchiorri, J. Silk

Forthcoming CMB experiments will allow us to accurately investigate the power spectrum at very small scales ($\ell > 1000$). We predict the level of the primary anisotropies, given the actual CMB measurements. The secondary anisotropies generated after matter-radiation decoupling contribute additional power in the tail of the CMB power spectrum. Together wit

Eric A. Minassian

The effects of spacetime quantization on black hole and big bang/big crunch singularities can be studied using new tools from (2+1)-dimensional quantum gravity. I investigate effects of spacetime quantization on singularities of the (2+1)-dimensional BTZ black hole and the (2+1)-dimensional torus universe. Hosoya has considered the BTZ black hole, and using

Andrew Das Arulsamy

The nature of normal state charge-carriers' dynamics and the transition in conduction and gap dimensionalities between 2D and 3D for YBa_2 Cu_3 O_{7-delta} and Bi_2 Sr_2 Ca_{1-x} Y_x Cu_2 O_8 high-T_c superconductors were described by computing and fitting the resistivity curves, rho(T,delta,x). These were carried out by utilizing the 2D and 3D Fermi liq

J. Lukierski, A. Nowicki

We argue that recently proposed by Amelino-Camelia et all [1,2] so-called doubly special relativity (DSR), with deformed boost transformations identical with the formulae for $κ$-deformed kinematics in bicrossproduct basis is a classical special relativity in nonlinear disguise. The choice of symmetric composition law for deformed fourmomenta as advocated in

Izabela Szlufarska, Arkadiusz Wojs, John J. Quinn

We report on the numerical study of the relaxation rates of nuclear spins coupled through the hyperfine interaction to a two dimensional electron gas (2DEG) at magnetic fields corresponding to both fractional and integral Landau level (LL) fillings nu. The Hamiltonians of up to 20 interacting electrons are diagonalized exactly in the spherical geometry, negl

Adam Doliwa

We introduce the Koenigs lattice, which is a new integrable reduction of the quadrilateral lattice (discrete conjugate net) and provides natural integrable discrete analogue of the Koenigs net. We construct the Darboux-type transformations of the Koenigs lattice and we show permutability of superpositions of such transformations, thus proving integrability o

M. Bordag, A. S. Goldhaber, P. van Nieuwenhuizen, D. Vassilevich

We apply zeta-function regularization to the kink and susy kink and compute its quantum mass. We fix ambiguities by the renormalization condition that the quantum mass vanishes as one lets the mass gap tend to infinity while keeping scattering data fixed. As an alternative we write the regulated sum over zero point energies in terms of the heat kernel and ap

Chen Gang, Liu Lianshou

Different methods in the study of anomalous scaling of factorial moments in high energy e+e- collisions are examined in some detail. It is shown that the horizontal and vertical factorial moments are equivalent only when they are used in combination with the cummulant variables. The influence of different reference frames and that of phase space restrictions

S. Fajfer, R. J. Oakes, T. N. Pham

Motivated by recent Belle measurement of the branching ratios $B^- \to π^+ π^- K^-$ and $B^- \to K^+ K^- K^-$ and $B^\pm \to χ_{c0} K^\pm$, we investigate the CP violating asymmetry in the partial widths for the decays $B^- \to π^+ π^- K^-$ and $B^- \to K^+ K^- K^-$, which results from the interference of the nonresonant decay amplitude with the resonant amp

Tien D. Kieu

We explore in the framework of Quantum Computation the notion of computability, which holds a central position in Mathematics and Theoretical Computer Science. A quantum algorithm that exploits the quantum adiabatic processes is considered for the Hilbert's tenth problem, which is equivalent to the Turing halting problem and known to be mathematically no

Markus Rampp, H. -Thomas Janka

Neutrino transport and neutrino interactions in dense matter play a crucial role in stellar core collapse, supernova explosions and neutron star formation. Here we present a detailed description of a new numerical code for treating the time and energy dependent neutrino transport in hydrodynamical simulations of such events. The code is based on a variable E

Asher Peres, Petra F. Scudo, Daniel R. Terno

We consider a single free spin 1/2 particle. The reduced density matrix for its spin is not covariant under Lorentz transformations. The spin entropy is not a relativistic scalar and has no invariant meaning.

Chris Beasley, Edward Witten

We consider the breaking of N=1 supersymmetry by non-zero G-flux when M-theory is compactified on a smooth manifold X of G_2 holonomy. Gukov has proposed a superpotential W to describe this breaking in the low-energy effective theory. We check this proposal by comparing the bosonic potential implied by W with the corresponding potential deduced from the elev

Xuan P. A. Gao, Allen P. Mills,, Arthur P. Ramirez, Steven H. Simon

We present measurements of the Joule heating of a 2D hole gas (2DHG) formed in a 30nm GaAs quantum well. The hole density is in the range (4.6-18.9)*10^9cm^-2 and exhibits an apparent metal-to-insulator transition (MIT) with a critical density 6*10^9 cm^-2. In the limit of zero heating power density P, the GaAs lattice is within 2 mK of the 6 mK base tempera

Annapurni Subramaniam, G. C. Anupama

This study aims at identifying and understanding the parent population of novae in the Large Magellanic Cloud (LMC) by studying the local, projected, stellar population. The star formation history of the local environment around novae is studied based on photometric data of stars and star clusters in the nova neighbourhood, available in the OGLE II survey an

Heon-Young Chang

The principal aim of observational helioseismology is to determine mode parameters of the solar oscillations as accurately as possible. Yet estimates of the mode parameters are subject to many sources of noise, including inevitable gaps in data, stochastic nature of excitation processes, interferences among modes. Another uncertainty in frequency determinati

Pavel Etingof, Dmitri Nikshych, Viktor Ostrik

Using a variety of methods developed in the literature (in particular, the theory of weak Hopf algebras), we prove a number of general results about fusion categories in characteristic zero. We show that the global dimension of a fusion category is always positive, and that the S-matrix of any modular category (not necessarily hermitian) is unitary. We also

Riccardo Capovilla, Jemal Guven

The stresses in a closed lipid membrane described by the Helfrich hamiltonian, quadratic in the extrinsic curvature, are identified using Noether's theorem. Three equations describe the conservation of the stress tensor: the normal projection is identified as the shape equation describing equilibrium configurations; the tangential projections are consist

R. Arnowitt, B. Dutta, T. Kamon, M. Tanaka

A measurement of the branching ratio for the rare decay mode B_s->mu mu at the Tevatron is an opportunity to test various supersymmetric scenarios. We investigate the prospects for studying this mode in Run II and estimate that CDF would be sensitive to this decay for a branching ratio > 1.2 \times 10^{-8} with 15 \invfb (or, if a similar analysis holds for

A. de la Macorra, G. German

We present a particle physics quintessence model which agrees well with existing cosmological data, including the position of the acoustic peaks. This model has an inverse power law potential (IPL) with $n=18/7\sim 2.57$ and it gives $\weff=-0.75$, an acoustic scale $l_A=307$ and a density contrast $\s8=0.95$. Models with $n>1$ have been said to be disfavore

P. C. Frisch, L. Grodnicki, D. E. Welty

The bulk flow velocity for the cluster of interstellar cloudlets within about 30 pc of the Sun is determined from optical and ultraviolet absorption line data, after omitting from the sample stars with circumstellar disks or variable emission lines and the active variable HR 1099. Ninety-six velocity components towards the remaining 60 stars yield a streamin

V. K. Vlasko-Vlasov, A. Koshelev, U. Welp, G. W. Crabtree

Josephson vortices are imaged magneto-optically due to their decoration with pancake vortices in $Bi_{2}Sr_{2}CaCu_{2}O_{8+d}$ single crystals. Peculiarities of interaction between the pancake and Josephson vortices (JV) depending on the values of crossing fields and temperature are studied based on the observations of these decoration patterns. Evidences of

Dorje C. Brody, Lane P. Hughston

The energy-based stochastic extension of the Schrodinger equation is a rather special nonlinear stochastic differential equation on Hilbert space, involving a single free parameter, that has been shown to be very useful for modelling the phenomenon of quantum state reduction. Here we construct a general closed form solution to this equation, for any given in

Karl Gustafson

I describe the early (1974--75) work I did on what is now called the Zeno problem in quantum mechanics. Then I propose a new formulation which may obviate a vexing problem of operator limits and which also may be more measurement-compatible.

Roland Faller

Solutions of {\it trans}$-$polyisoprene in cyclohexane are investigated in atomistic detail at different compositions at two different temperatures. We investigate the influence of polymer concentration on the dynamics of the solvent molecules and the structure of the solvation shell. The double bonds along the polymer backbone are preferentially approached

Michael Meyer-Hermann

During germinal center reactions the appearance of two specific zones is observed: the dark and the light zone. Up to now, the origin and function of these zones are poorly understood. In the framework of a stochastic and discrete model several possible pathways of zone development during germinal center reactions are investigated. The importance of the zone

P. -G. Reinhard, V. O. Nesterenko, E. Suraud, S. El Gammal

We study the scissors mode (orbital M1 excitations) in small Na clusters, triaxial metal clusters ${\rm Na}_{12}$ and ${\rm Na}_{16}$ and the close-to-spherical ${{\rm Na}_9}^+$, all described in DFT with detailed ionic background. The scissors modes built on spin-saturated ground and spin-polarized isomeric states are analyzed in virtue of both macroscopic

The MACRO Collaboration

Muon energy measurement represents an important issue for any experiment addressing neutrino induced upgoing muon studies. Since the neutrino oscillation probability depends on the neutrino energy, a measurement of the muon energy adds an important piece of information concerning the neutrino system. We show in this paper how the MACRO limited streamer tube

D. Yu. Tsipenyuk

A run of preliminary experiments was carried out to check the prediction of possible gravitational field generation process arising by stopping of charged massive particles in a substance predicted by the recently developed Extended Space Model (ESM).

David H. Douglass, Drew R. Abrams, David M. Baranson, B. David Clader

We propose a scenario that explains many of the Pacific Ocean climate phenomena that are called El Nino/ La Nina. This scenario requires an event, which we call a Super-Nino Event. It dominates other phenomena when it occurs. A template of this event has been constructed giving the time evolution, which is an alternating sequence of 'El Ninos' and &#

Jie Liang, Jinfeng Zhang, Rong Chen

Voids exist in proteins as packing defects and are often associated with protein functions. We study the statistical geometry of voids in two-dimensional lattice chain polymers. We define voids as topological features and develop a simple algorithm for their detection. For short chains, void geometry is examined by enumerating all conformations. For long cha

Rainer E. Zimmermann

With a view to the ongoing Bologna project (www.arXiv.org/pdf/nlin.AO/0109025) general organizing principles of emergent structures in social systems are being discussed with a view to the meaning of decentralization. It is proposed to introduce decentralization as a principle for organizing emergent structures in a generic way utilizing aspects of the insig

Carlos R. Fadragas, Juan V. Lorenzo-Ginori, Ruben Orozco-Morales

This paper is devoted to a discussion of the Discrete Fourier Transform (DFT) representation of a chaotic finite-duration sequence. This representation has the advantage that is itself a finite-duration sequence corresponding to samples equally spaced in the frequency domain. The Fast Fourier Transform (FFT) algoritm allows us an effective computation, and i

Pierre Collet, Jean-Pierre Eckmann

We give upper and lower bounds on the number of graphs of fixed degree which have a positive density of triangles. In particular, we show that there are very few such graphs, when compared to the number of graphs without this restriction. We also show that in this case the triangles seem to cluster even at low density.

Jack Allen, Sukanto Bhattacharya, Florentin Smarandache

Each individual investor is different, with different financial goals, different levels of risk tolerance and different personal preferences. From the point of view of investment management, these characteristics are often defined as objectives and constraints. Objectives can be the type of return being sought, while constraints include factors such as time

Karl Petersen, Anthony Quas, Sujin Shin

Given an irreducible subshift of finite type X, a subshift Y, a factor map π: X \to Y, and an ergodic invariant measure νon Y, there can exist more than one ergodic measure on X which projects to νand has maximal entropy among all measures in the fiber, but there is an explicit bound on the number of such maximal entropy preimages.

David P. Blecher, Roger R. Smith, Vrej Zarikian

In [BEZ] the notion of a complete one-sided M-ideal for an operator space X was introduced as a generalization of Alfsen and Effros' notion of an M-ideal for a Banach space [AE72]. In particular, various equivalent formulations of complete one-sided M-projections were given. In this paper, some sharper equivalent formulations are given in the special sit

Mikhail Kogan, Andrei Zelevinsky

We provide an explicit description of symplectic leaves of a simply connected connected semisimple complex Lie group equipped with the standard Poisson-Lie structure. This sharpens previously known descriptions of the symplectic leaves as connected components of certain varieties. Our main tool is the machinery of twisted generalized minors. They also allow

P. Collet, S. Martinez, J. San Martin

Using a new inequality relating the heat kernel and the probability of survival, we prove asymptotic ratio limit theorems for the heat kernel (and survival probability) in general Benedicks domains. In particular, the dimension of the cone of positive harmonic measures with Dirichlet boundary condition can be derived from the rate of convergence to zero of t

Dmitri V. Millionschikov

We study the cohomology $H^*_{λω}(G/Γ, {\mathbb C})$ of the deRham complex $Λ^*(G/Γ)\otimes{\mathbb C}$ of a compact solvmanifold $G/Γ$ with a deformed differential $d_{λω}=d + λω$, where $ω$ is a closed 1-form. This cohomology naturally arises in the Morse-Novikov theory. We show that for a solvable Lie group $G$ with a completely solvable Lie algebra $\mat

Armen Edigarian, Jan Wiegerinck

Let D_1 be a subdomain of D_2 in the complex plane CC. Under very mild conditions on D_2 we show that there exist holomorphic functions f, defined on D_1 with the property that $f$ is nowhere extendible across the boundary of D_1, while the graph of f over D_1 is NOT complete pluripolar in D_2 times CC. This refutes a conjecture of Levenberg, Martin and Pole

Stancho Dimiev, Krassimir Markov

In this paper Gauss integers are used for to develop some geometry of full Erdoes graphs which vertics are points with integer coordinates. These graphs are called Diophantine figures.

Ruth Charney, John Meier, Kim Whittlesey

A Garside group is a group admitting a finite lattice generating set D. Using techniques developed by Bestvina for Artin groups of finite type, we construct K(π,1)s for Garside groups. This construction shows that the (co)homology of any Garside group G is easily computed given the lattice D, and there is a simple sufficient condition that implies G is a dua

Orlin Stoytchev

A class of representations is described for the central extensions, found by Etingof and Frenkel, of current algebras over Riemann surfaces. Their irreducibility is proved. The possibility/impossibility to obtain integrable representations within that class is discussed briefly.

Leonid Polterovich, Mikhail Sodin

The paper is withdrawn.

Sergio Ferrara, Emery Sokatchev

We obtain by superfield methods the exceptional representations of the OSp(2N/4,R) and SU(2,2/1) superalgebras which extend to supersingletons of SU(2,2/2N) and F(4), respectively. These representations describe superconformally coupled multiplets and appear in three- and four-dimensional superconformal field theories which are holographic descriptions of ce

Arvind Narayan Vaidya, Rafael de Lima Rodrigues

We do not think that the relativistic Morse potential problem has been correctly formulated and solved by Alhaidari (Phys. Rev. Lett. 87, 210405 (2001)).

G. Delfino, P. Grinza, G. Mussardo

When a quantum field theory possesses topological excitations in a phase with spontaneously broken symmetry, these are created by operators which are non-local with respect to the order parameter. Due to non-locality, such disorder operators have non-trivial correlation functions even in free massive theories. In two dimensions, these correlators can be expr

G. Grensing

The path integral for ghost fermions, which is heuristically made use of in the Batalin- Fradkin-Vilkovisky approach to quantization of constrained systems, is derived from first principles. The derivation turns out to be rather different from that of physical fermions since the definition of Dirac states for ghost fermions is subtle. With these results at h

M. Cvetic, G. W. Gibbons, H. Lu, C. N. Pope

We consider spaces M_7 and M_8 of G_2 holonomy and Spin(7) holonomy in seven and eight dimensions, with a U(1) isometry. For metrics where the length of the associated circle is everywhere finite and non-zero, one can perform a Kaluza-Klein reduction of supersymmetric M-theory solutions (Minkowksi)_4\times M_7 or (Minkowksi)_3\times M_8, to give supersymmetr