December 2001 arXiv papers — page 22

E. A. Jagla

We have performed molecular dynamics simulations of solid-solid contacts lubricated by a model fluid displaying many of the properties of water, particularly its expansive freezing. Near the region where expansive freezing occurs, the lubricating film remains fluid, and the friction force decreases linearly as the shear velocity is reduced. No sign of stick-

Licia Verde, Alan F. Heavens, Will J. Percival, Sabino Matarrese

We compute the bispectrum of the 2dF Galaxy Redshift Survey (2dFGRS) and use it to measure the bias parameter of the galaxies. This parameter quantifies the strength of clustering of the galaxies relative to the mass in the Universe. By analysing 80 million triangle configurations in the wavenumber range 0.1 < k < 0.5 h/Mpc (i.e. on scales roughly between 5

Amit P. Mehta, Andrea C. Mills, Karin Dahmen, James P. Sethna

In order to test if the universal aspects of Barkhausen noise in magnetic materials can be predicted from recent variants of the non-equilibrium zero temperature Random Field Ising Model (RFIM), we perform a quantitative study of the universal scaling function derived from the Barkhausen pulse shape in simulations and experiment. Through data collapses and s

H. A. Fertig

The unbinding of vortex-antivortex pairs for the classical two-dimensional XY model in a magnetic field is studied. A single such pair is connected by a string of overturned spins, leading to linear confinement. We show that this system supports two phase transitions, one in which closed strings proliferate, and a second in which vortices unbind. The transit

Joao Pulido

A statistical analysis of the solar neutrino data is presented assuming the solar neutrino deficit to be resolved by the resonant interaction of the neutrino magnetic moment with the solar magnetic field. Four field profiles are investigated, all exhibiting a rapid increase across the bottom of the convective zone, one of them closely following the requireme

M. Maltoni, T. Schwetz, J. W. F. Valle

We present a unified global analysis of neutrino oscillation data within the framework of the four-neutrino mass schemes (3+1) and (2+2). We include all data from solar and atmospheric neutrino experiments, as well as information from short-baseline experiments including LSND. If we combine only solar and atmospheric neutrino data, (3+1) schemes are clearly

Masashi Hayakawa, Toichiro Kinoshita

We correct the error in the sign of the pseudoscalar pole contribution to the muon g-2, which dominates the O(alpha^3) hadronic light-by-light scattering effect. The error originates from our oversight of a feature of the algebraic manipulation program FORM which defines the epsilon-tensor in such a way that it satisfies the relation epsilon_{mu_1 mu_2 mu_3

J. M. Drummond

We discuss the relation between the superembedding method for deriving worldvolume actions for D-branes and the method of Partially Broken Global Supersymmetry based upon linear and non-linear realisations of SUSY. We give the explicit relation for the cases of space filling branes in 3 and 4 dimensions and show that the standard F-constraint of the superemb

Chao-Shang Huang, Jing Jiang, Tianjun Li, Wei Liao

We study the $N=2$ supersymmetric $E_6$ models on the 6-dimensional space-time where the supersymmetry and gauge symmetry can be broken by the discrete symmetry. On the space-time $M^4\times S^1/(Z_2\times Z_2&#39;) \times S^1/(Z_2\times Z_2&#39;)$, for the zero modes, we obtain the 4-dimensional $N=1$ supersymmetric models with gauge groups $SU(3)\times SU(

M. Cvetic, S. Nojiri, S. D. Odintsov

We investigate the charged Schwarzschild-Anti-deSitter (SAdS) BH thermodynamics in 5d Einstein-Gauss-Bonnet gravity with electromagnetic field. The Hawking-Page phase transitions between SAdS BH and pure AdS space are studied. The corresponding phase diagrams (with critical line defined by GB term coefficient and electric charge) are drawn. The possibility t

R. R. Metsaev

We construct the covariant $κ$-symmetric superstring action for type $IIB$ superstring on plane wave space supported by Ramond-Ramond background. The action is defined as a 2d sigma-model on the coset superspace. We fix the fermionic and bosonic light-cone gauges in the covariant Green-Schwarz superstring action and find the light-cone string Lagrangian and

S Teber, B P Stojkovic, S A Brazovskii, A R Bishop

The 2-fold degeneracy of the ground state of a quasi-one-dimensional system allows it to support topological excitations such as solitons. We study the combined effects of Coulomb interactions and confinement due to interchain coupling on the statistics of such defects. We concentrate on a 2D case which may correspond to monolayers of polyacetylene or other

Christian Hainzl, Vitali Vougalter, Semjon A. Vugalter

We consider a spinless particle coupled to a photon field and prove that even if the Schrödinger operator $p^2 + V$ does not have eigenvalues the system can have a ground state. We describe the coupling by means of the Pauli-Fierz Hamiltonian and our result holds in the case where the coupling constant $α$ is small.

F. Guinea

The amplitude of the Bohm-Aharonov oscillations of a particle moving around a ring threaded by a magnetic flux and coupled to different dissipative environments is studied. The decay of the oscillations when increasing the radius of the ring is shown to depend on the spatial features of the coupling. When the environment is modelled by the Caldeira-Leggett b

Stanislaw Mrowczynski

We study the collective quark excitations in an extremely anisotropic system of two interpenetrating streams of the quark-gluon plasma. In contrast to the gluon modes, all quark ones appear to be stable in such a system. Even more, the quark modes in the two-stream system are very similar to those in the isotropic plasma.

Nikolai M. Chtchelkatchev, Gianni Blatter, Gordey B. Lesovik, Thierry Martin

Bell-inequality checks constitute a probe of entanglement -- given a source of entangled particles, their violation are a signature of the non-local nature of quantum mechanics. Here, we study a solid state device producing pairs of entangled electrons, a superconductor emitting Cooper pairs properly split into the two arms of a normal-metallic fork with the

Mang Feng, Xiaoguang Wang

We propose a scheme to perform basic gates of quantum computing and prepare entangled states in a system with cold trapped ions located in a single mode optical cavity. General quantum computing can be made with both motional state of the trapped ion and cavity state being qubits. We can also generate different kinds of entangled states in such a system with

Rachael M. Hawkins, James E. Lidsey

It is shown that the dynamics of cosmologies sourced by a mixture of perfect fluids and self-interacting scalar fields are described by the non-linear, Ermakov-Pinney equation. The general solution of this equation can be expressed in terms of particular solutions to a related, linear differential equation. This characteristic is employed to derive exact cos

G. G. Varzugin, A. S. Chistyakov

Axially symmetric, stationary solutions of the Einstein-Maxwell equations with disconnected event horizon are studied by developing a method of explicit integration of the corresponding boundary-value problem. This problem is reduced to non-leaner system of algebraic equations which gives relations between the masses, the angular momenta, the angular velocit

G. Golse, J. -P. Kneib

We introduce analytical expressions for a pseudo fully analytical elliptical projected Navarro, Frenk & White (NFW) mass profile to be used in lensing equations. We propose a formalism that incorporates the ellipticity into the expression for the lens potential, producing a pseudo-elliptical mass distribution. This approach can be implemented to any circular

H. Caps, N. Vandewalle

An experimental study of a binary granular mixture submitted to a transient shear flow in a cylindrical container is reported. The formation of ripples with a spiral shape is observed. The appearance of phase segregation in those spiral patterns is shown. The relative grain size bewteen sand species is found to be a relevant parameter leading to phase segreg

Hyung Do Kim, Jihn E. Kim, Hyun Min Lee

A supersymmetric 5D SU(5) grand unification is considered. The SU(5) is broken down to $G_{SM}=SU(3)\times SU(2)\times U(1)$ by the $Z_2\times Z_2&#39;$ assignment of the bulk field(s). The matter fields are located at the fixed point(s). In the bulk, a Higgs multiplet $\bar 5_H$(containing the bottom doublet $H_1$) and the SU(5) gauge multiplet are located.

Kumar S. Gupta, Siddhartha Sen

We study the excitations of a massive Schwarzschild black hole of mass M resulting from the capture of infalling matter described by a massless scalar field. The near-horizon dynamics of this system is governed by a Hamiltonian which is related to the Virasoro algebra and admits a one-parameter family of self-adjoint extensions described by a parameter z \in

M. Kawasaki, Masahide Yamaguchi

We propose a topological inflation model in supergravity. In this model, the vacuum expectation value (VEV) of a scalar field takes a value much larger than the gravitational scale $M_{G} \simeq 2.4 \times 10^{18}$ GeV, which is large enough to cause topological inflation. On the other hand, expansions of the Kähler potential and the superpotential beyond th

Gang Chen, Yuan Hu, Lianshou Liu, W. Kittel

Both three- and one-dimensional studies of local multiplicity fluctuations in hadronic Z decay are performed using data of the L3 experiment at LEP. The normalized factorial moments in three dimensions exhibit power-law scaling, indicating that the fluctuations are isotropic, which correspends to a self-similar fractal. A detailed study of the corresponding

Naoki Watanabe, Masaru Tsukada

A numerical scheme for solving the time-evolution of wave functions under the time dependent Kohn-Sham equation has been developed. Since the effective Hamiltonian depends on the wave functions, the wave functions and the effective Hamiltonian should evolve consistently with each other. For this purpose, a self-consistent loop is required at every time-step

Sergey Pankov, Gabriel Kotliar, Yukitoshi Motome

The extended Dynamical Mean Field Equations (EDMFT) are analyzed using semiclassical methods for a model describing an interacting fermi-bose system. We compare the semiclassical approach with the exact QMC (Quantum Montecarlo) method. We found the transition to an ordered state to be of the first order for any dimension below four.

Ernest C. Y. Ho, Harold W. Fearing, Wolfgang Schadow

The rate of the nuclear reaction $^3He+μ^- \to ^3H+γ+ν_μ$ has been calculated using both the elementary particle model (EPM) approach and the impulse approximation (IA) approach. Using the EPM approach, the exclusive statistical radiative muon capture (RMC) rate for photon energy greater than 57 MeV is found to be $0.245 s^{-1}$ and the ordinary muon capture

Seth Lloyd

All communication channels are at bottom quantum mechanical. Quantum mechanics contributes both obstacles to communication in the form of noise, and opportunities in the use of intrinsically quantum representations for information. This paper investigates the trade-off between power and communication rate for coupled quantum channels. By exploiting quantum c

J. G. Gilson

It is shown that the fine structure constant alpha has the same value that &#34;characterises&#34; a relation, denoted by alpha_137(29*137), between a representation of the cyclic group of order 29*137 and the induced representation for the cyclic subgroup of order 137. The value of this characteristic is alpha_137(29*137) = 0.007297352532... . The complemen

Thomas Gorin, Thomas H. Seligman

In order to analyze the effect of chaos or order on the rate of decoherence in a subsystem, we aim to distinguish effects of the two types of dynamics by choosing initial states as random product states from two factor spaces representing two subsystems. We introduce a random matrix model that permits to vary the coupling strength between the subsystems. The

B. Deb, G. S. Agarwal

We show that it is possible to entangle three different many-particle states by Bragg spectroscopy with nonclassical light in a Bose condensate of weakly interacting atomic gases. Among these three states, two are of atoms corresponding to two opposite momentum side-modes of the condensate; and the other is of single-mode photons of the output probe beam. We

Massimo Coraddu, Marcello Lissia, Giuseppe Mezzorani, Piero Quarati

We show that moderate deviations from the Maxwell-Boltzmann energy distribution can increase deuterium reaction rates enough to contribute to the heating of Jupiter. These deviations are compatible with the violation of extensivity expected from temperature and density conditions inside Jupiter.

A. V. Rykov

Vacuum, where matter exists is an objective reality of Nature. It has a structure consists of electrical massless dipoles. This structure is responsible for gravitation, inertia and propagation of light. The structure can be influenced by the electrical, magnetic forces and by radiation and thus control the gravitation and inertia.

H. A. Yamani, A. D. Alhaidari, M. S. Abdelmonem

The restriction imposed on the J-matrix method of using specific L2 bases is lifted without compromising any of the advantages that it offers. This opens the door to a wider range of application of the method to physical problems beyond the restrictive SO(2,1) dynamical symmetry. The numerical scheme developed to achieve this objective projects the J-matrix

D. G. Aronson, S. I. Betelu, I. G. Kevrekidis

We present a systematic computational approach to the study of self-similar dynamics. The approach, through the use of what can be thought of as a ``dynamic pinning condition&#34; factors out self-similarity, and yields a transformed, non-local evolution equation. The approach, which is capable of treating both first and second kind self-similar solutions, y

Zbigniew Peradzynski, Hanna E. Makaruk, Robert M. Owczarek

Structure constants of the $su(N)$ ($N$ odd) Lie algebras converge when N goes to infinity to the structure constants of the Lie algebra {\it sdiff}$(T^2)$ of the group of area-preserving diffeomorphisms of a 2D torus. Thus Zeitlin and others hypothesized that solutions of the Euler equations associated with $su(N)$ algebras converge to solutions of the Eule

Dariush Ehsani

We study the solution of the d-bar-Neumann problem on (0,1)-forms on the product of two half-planes in C^2. In, particular, we show the solution can be decomposed into functions smooth up to the boundary and functions which are singular at the singular points of the boundary. Furthermore, we show the singular functions are log and arctan terms.

Kiumars Kaveh

A theorem due to D. Bernstein states that Euler characteristic of a hypersurface defined by a polynomial f in (C\{0})^n is equal (upto a sign) to n! times volume of the Newton polyhedron of f. This result is related to algebaric torus actions and toric varieties. In this thesis, I prove that one can generalize the above result to actions of reductive groups

Salih Celik

We show that the algebra of functions on the Grassmann supergroup Gr$_q(1| 1)$ has a (graded) Hopf algebra structure related to GL$_q(1| 1)$.

Salih Celik

Hopf algebra structures on the extended q-superplane and its differential algebra are defined. An algebra of forms which are obtained from the generators of the extended q-superplane is introduced and its Hopf algebra structure is given

Salih Celik

The two-parametric quantum deformation of the algebra of coordinate functions on the supergroup GL$(1| 1)$ via a contraction of GL$_{p,q}(1| 1)$ is presented. Related differential calculus on the quantum superplane is introduced.

Salih Celik

We introduce a construction of the differential calculus on the quantum supergroup GL$_{p,q}(1| 1)$. We obtain two differential calculi, respectively, associated with the left and right Cartan-Maurer one-forms. We also obtain the quantum superalgebra of GL$_{p,q}(1| 1)$. Although all of the structures we obtain are derived without an R matrix, they neverthle

Chris A. J. Klaassen, J. Theo Runnenburg

Consider a string of $n$ positions, i.e. a discrete string of length $n$. Units of length $k$ are placed at random on this string in such a way that they do not overlap, and as often as possible, i.e. until all spacings between neighboring units have length less than $k$. When centered and scaled by $n^{-1/2}$ the resulting numbers of spacings of length $1,

Vladlen Timorin

We classify all Kahler metrics in an open subset of $C^2$ whose real geodesics are circles. All such metrics are equivalent (via complex projective transformations) to Fubini metrics (i.e. to Fubini-Study metric on $CP^2$ restricted to an affine chart, to the complex hyperbolic metric in the unit ball model or to the Euclidean metric).

Howard Kleiman

In math.CO/0111309, we used admissible permutations and a variant of the Floyd-Warshall Algorithm to obtain an optimal solution to the Assignment Problem and an approximate solution to the Traveling Salesman Problem. Here we give a large, detailed illustration of how the algorithms are applied.

Jonathan Holland, George Sparling

This paper constructs a family of conformally invariant differential operators acting on spinor densities with leading part a power of the Dirac operator. The construction applies for all powers in odd dimensions, and only for finitely many powers in even dimensions. These operators arise naturally as obstructions to formal solution of the Dirac equation on

J. Colliander, C. Kenig, G. Staffilani

Oscillatory integral techniques are used to study the well-posedness of the KP-I equation for initial data that are small with respect to the norm of a weighted Sobolev space involving derivatives of total order no larger than 2.

A. R. Fazio, S. P. Sorella

A possible mechanism accounting for monopole configurations in continuum Yang-Mills theories is discussed. The presence of the gauge fixing term is taken into account.

C. P. Burgess, J. M. Cline, N. R. Constable, H. Firouzjahi

We study a generalization of the Randall-Sundrum mechanism for generating the weak/Planck hierarchy, which uses two rather than one warped extra dimension, and which requires no negative tension branes. A 4-brane with one exponentially large compact dimension plays the role of the Planck brane. We investigate the dynamical stability with respect to graviton,

Gordon W. Semenoff

In this lecture I will review some results about the discrete light-cone quantization (DLCQ) of strings and some connections of the results with matrix string theory. I will review arguments which show that, in the path integral representation of the thermal free energy of a string, the compactifications which are necessary to obtain discrete light-cone quan

G. Bonelli

An on-shell model for the supersymmetric index counting multiplicities of BPS states of the M5-brane theory is reviewed. In particular we explicitly study the tensionless Little String states appearing at intersections in a bound state of $N$ 5-branes wrapped on a six-manifold with product topology $M_4\times T^2$.

Saul Youssef

Probability theory can be modified in essentially one way while maintaining consistency with the basic Bayesian framework. This modification results in copies of standard probability theory for real, complex or quaternion probabilities. These copies, in turn, allow one to derive quantum theory while restoring standard probability theory in the classical limi

Gabriel H. Flores, N. F. Svaiter

In this paper we review how to reconstruct scalar field theories in two dimensional spacetime starting from solvable Schrodinger equations. Three different Schrodinger potentials are analyzed. We obtained two new models starting from the Morse and Scarf II hyperbolic potentials, {\it i.e}, the $U(ϕ)=ϕ^2\ln^2(ϕ^2)$ model and $U(ϕ)=ϕ^2\cos^2(\ln(ϕ^2))$ model r

P. Aliani, V. Antonelli, M. Picariello, E. Torrente-Lujan

We present an updated analysis of all the data available about solar neutrinos, including the charged current SNO results. The best fit of the data is obtained in the Large Mixing Angle region, but different solutions are still possible. We also study the perspectives of Borexino and conclude that this experiment, with a parallel analysis of total rate and d

W. Schweiger

We consider various relativistic models for the valence Fock-state wave function of the pion. These models are obtained from simple instant-form wave functions by applying a Melosh rotation to the spin part and by imposing physical constraints on the parameters. We discuss how the soft and the hard (perturbative) parts of the electromagnetic form factor are

T. S. Jensen, V. E. Markushin

The differential and total cross sections for the scattering of muonic, pionic, kaonic and antiprotonic hydrogen in excited states from atomic hydrogen have been calculated for the purpose of atomic cascade calculations. The scattering problem is treated in a fully quantum mechanical framework which takes the energy shifts and, in the case of the hadronic at

F. Pisano, N. O. Reis

Defined by Lord Kelvin as the science of measurement it is described a fundamental fact of physics. The so called `natural&#39; units represent the unique system of units conveniently used in the realm of High Energy Physics. The system of natural units is defined by the consistent providing of the adimensional unit value to the velocity c of the eletromagne

M. Burkardt, S. K. Seal

We present results from a first study of $B$-mesons that is based on a transverse lattice formulation of light-front QCD. The shape of the Isgur-Wise form factor is in very good agreement with experimental data. However, the calculations yield rather large values for $f_B$ and $\barΛ$ compared to contemporary calculations based on other techniques.

Kjell Prytz

The pomeron structure function is extracted from the latest H1 data and are subject to a QCD analysis. The result shows evidence for gluon recombination.

Kazuyuki Kanaya

Numerical simulation of lattice QCD is now an indispensable tool for investigating non-perturbative properties of quarks at low energies. In this paper, I introduce a recent lattice QCD calculation of light hadron spectrum and quark masses performed on a dedicated parallel computer, CP-PACS. From a simulation of QCD with two flavors of dynamical quarks, we f

Ralph Engel

A brief introduction to the theory and phenomenology of soft interactions is given, focusing on total and elastic cross sections and multiparticle production.

S. Kim, John B. Kogut, Maria-Paola Lombardo

By adding a small, irrelevant four fermi interaction to the action of noncompact lattice Quantum Electrodynamics (QED), the theory can be simulated with massless quarks in a vacuum free of lattice monopoles. The lattice theory possesses a second order chiral phase transition which we show is logarithmically trivial, with the same systematics as the Nambu-Jon

I. Montvay

Recent development in numerical simulations of supersymmetric Yang-Mills (SYM) theories on the lattice is reviewed.

Sinya Aoki

We investigate chiral properties of the domain-wall fermion (DWF) system. After a brief introduction for the DWF, we summarize the recent numerical results on the chiral properties of the domain-wall QCD (DWQCD), which seem mutually inconsistent. We next derive a formula which connects a chiral symmetry breaking term in the five dimensional DWF Ward-Takahash

PACS Collaboration, S. Aoki, Y. Aoki, S. Ejiri

We formulate and numerically test the Schrödinger functional scheme for domain-wall QCD. We then apply it to a non-perturbative calculation of the renormalization factors for vector and axial-vector currents in quenched domain-wall QCD with plaquette and renormalization group improved gauge actions at $a^{-1}\simeq 2$ GeV.

G. Giacomelli, L. Patrizii

We discuss the experimental situation of direct searches at accelerators for Dirac magnetic monopoles, and in the penetrating cosmic radiation for the superheavy magnetic monopoles predicted by GUT theories. We also discuss the searches for intermediate mass monopoles (wich are predicted by theories in extra dimensions), and for nuclearites and Q-balls.

A. G. Afonin, V. M. Biryukov, V. T. Baranov, V. N. Chepegin

Silicon crystal was channeling and extracting 70-GeV protons from the U-70 accelerator with efficiency of 85.3+-2.8% as measured for a beam of 10^12 protons directed towards crystals of 2 mm length in spills of 1-2 s duration. The experimental data follow very well the prediction of Monte Carlo simulations. This success is important to devise a more efficien

G. Mazzitelli, F. Murtas, P. Valente

The KLOE experiment at the Frascati phi-factory DAPHNE, designed to measure $\Re(ε^\prime/ε)$, began preliminary data taking in the Fall of 1999. A large database structure, which logs information coming from the DAPHNE control system and the KLOE slow control and data acquisition systems, has been developed. Data from detector monitoring, online event proce

D. Astefanesei, E. Radu

Some properties of an exact solution due to Vaidya, describing the gravitational field produced by a point particle in the background of the static Einstein universe are examined. The maximal analytic extension and the nature of the singularities of the model are discussed. By using the Euclidean approach, some quantum aspects are analysed and the thermodyna

Sascha Husa

This talk reports on recent progress toward the semiglobal study of asymptotically flat spacetimes within numerical relativity. The development of a 3D solver for asymptotically Minkowski-like hyperboloidal initial data has rendered possible the application of Friedrich&#39;s conformal field equations to astrophysically interesting spacetimes. As a first app

R W Tucker, C Wang

This paper explores the interaction of weak gravitational fields with slender elastic materials in space and estimates their sensitivities for the detection of gravitational waves with frequencies between $10^{-4}$ and 1 Hz. The dynamic behaviour of such slender structures is ideally suited to analysis by the simple theory of Cosserat rods. Such a descriptio

T. Tmmalm

There are many models relating an accretion disk of Black Hole to jet outflow. The herein heuristic model describes the continuation of an external accretion disk to an internal accretion disk for less than Black Hole horizon, and subsequent polar jet outflow along polar axis out of polar vortex wherein the event horizon is no longer descriptive.

Sudip Chakravarty, Hae-Young Kee, Chetan Nayak

The pseudogap phase of the cuprate superconductors is argued to be characterized by a hidden broken symmetry of d-wave character in the particle-hole channel that leads to staggered orbital magnetism. This proposal has many striking phenomenological consequences, but the most direct signature of this order should be visible in the neutron scattering experime

Miriam A. Forman

This paper presents calculations of the Castaing (Physica D, 46, 177, 1990) cascade kernels for five well-known models of the turbulent cascade and demonstrates that these kernels provide conceptually simple and direct descriptions of turbulence models equivalent to their multifractal spectra. The problem with a log-normal model seems to be that its Castaing

G. M. Zhao

In a recent paper, Nagaev cited the unpublished paper by Franck et al.to support his theoretical model for the mechanism of the giant isotope effect observed in La_{1-x}Ca_{x}MnO_{3+y} (x = 0.20, y > 0). His model suggests that the off-stoichiometric oxygen content depends strongly on the oxygen isotope mass, which leads to a giant oxygen-isotope effect. Her

G. Korniss, M. A. Novotny, P. A. Rikvold, H. Guclu

Efficient and faithful parallel simulation of large asynchronous systems is a challenging computational problem. It requires using the concept of local simulated times and a synchronization scheme. We study the scalability of massively parallel algorithms for discrete-event simulations which employ conservative synchronization to enforce causality. We do thi

M. E. Larraga, J. A. del Rio, Anita Mehta

We present a model of traffic flow, with rules that describe the behaviour of automated vehicles in an open system. We show first of all that the fundamental diagram of this system collapses to a point, where states of free and jammed traffic can coexist in phase space. This leads us to consider separately the roles of average velocities and densities as bet

Ya. M. Blanter, V. M. Vinokur

We develop an instanton technique for calculations of correlation functions characterizing statistical behavior of the elastic string in disordered media and apply the proposed approach to correlations of string free energies corresponding to different low-lying metastable positions. We find high-energy tails of correlation functions for the case of long-ran

A. M. Gabovich, A. I. Voitenko, Mai Suan Li, H. Szymczak

Electronic heat capacity was calculated for a mesoscopically disordered s-wave superconductor treated as a spatial ensemble of domains with a continuously varying superconducting properties. The domains are assumed to have sizes larger than the coherence length. Each domain is characterized by a certain critical temperature. The averaging over the supercondu

Andreas Klemm, Ralf Metzler, Rainer Kimmich

Quasi two-dimensional random site percolation model objects were fabricate based on computer generated templates. Samples consisting of two compartments, a reservoir of H$_2$O gel attached to a percolation model object which was initially filled with D$_2$O, were examined with NMR (nuclear magnetic resonance) microscopy for rendering proton spin density maps

Przemyslaw Repetowicz

Low-temperature series are calculated for the free energy, magnetisation, susceptibility and field-derivatives of the susceptibility in the Ising model on the quasiperiodic Penrose lattice. The series are computed to order 20 and estimates of the critical exponents alpha, beta and gamma are obtained from Pade approximants.

Markus Deserno, Christian Holm

The cell-model and its treatment on the Poisson-Boltzmann level are two important concepts in the theoretical description of charged macromolecules. In this brief contribution to the Proceedings of the NATO-ASI on ``Electrostatic Effects in Soft Matter and Biophysics&#39;&#39;, which took place in Les Houches from Oct. 1-13, 2000, we provide an introduction

T. C. Lubensky, Ranjan Mukhopadhyay, Leo Radzihovsky, Xiangjun Xing

A nematic liquid-crystal gel is a macroscopically homogeneous elastic medium with the rotational symmetry of a nematic liquid crystal. In this paper, we develop a general approach to the study of these gels that incorporates all underlying symmetries. After reviewing traditional elasticity and clarifying the role of broken rotational symmetries in both the r

D. Bolle, T. Verbeiren

Starting from the mutual information we present a method in order to find a hamiltonian for a fully connected neural network model with an arbitrary, finite number of neuron states, Q. For small initial correlations between the neurons and the patterns it leads to optimal retrieval performance. For binary neurons, Q=2, and biased patterns we recover the Hopf

Detlef Lehmann

For a gaussian interaction V(x,y)=λe^{-(x^2+y^2)/r^2} with long range r>>l_B, l_B the magnetic length, we rigorously prove that the eigenvalues of the finite volume Hamiltonian H_{N,LL}=P_{LL} H_N P_{LL}, H_N=\sum_{i=1}^N [-i\hbar \nabla_{x_i}-eA(x_i)]^2+\sum_{i,j; i\ne j} V(x_i-x_j), \rotA=(0,0,B), and P_{LL} the projection onto the lowest Landau level, are

A. A. Louis, P. G. Bolhuis, R. Finken, V. Krakoviack

We show how to coarse grain polymers in a good solvent as single particles, interacting with density-independent or density-dependent interactions. These interactions can be between the centres of mass, the mid-points or end-points of the polymers. We also show how to extend these methods to polymers in poor solvents and mixtures of polymers. Treating polyme

E. V. Deviatov, A. A. Shashkin, V. T. Dolgopolov, H. -J. Kutschera

We study the plateaux of the integer quantum Hall resistance in a bilayer electron system in tilted magnetic fields. In a narrow range of tilt angles and at certain magnetic fields, the plateau level deviates appreciably from the quantized value with no dissipative transport emerging. A qualitative account of the effect is given in terms of decoupling of the

M. Vicari, A. Braggio, E. Galleani d&#39;Agliano, M. Sassetti

The ac-transport properties of a one-dimensional quantum dot with non-Fermi liquid correlations are investigated. It is found that the linear photoconductance is drastically influenced by the interaction. Temperature and voltage dependences of the sideband peaks are treated in detail. Characteristic Luttinger liquid power laws are founded.

J. H. Park, S. K. Kwon, B. I. Min

Based on the theoretical exploration of electronic structures, we propose that the ordered double perovskites LaAVRuO$_6$ and LaVO$_3$/ARuO$_3$ (001) superlattice (A = Ca, Sr and Ba) are strong candidates for half-metallic (HM) antiferromagnets (AFMs). %LaAVRuO$_6$ and LaVO$_3$/ARuO$_3$ have the %100% spin polarizations at the Fermi level but with zero %tota

Ar. Abanov, Andrey V. Chubukov

Motivated by recent experiments by Basov {\it et al}, we study the differential sum rule for the effective scattering rate $1/τ(ω)$. We show that in a dirty BCS superconductor, the area under $1/τ(ω)$ does not change between the normal and the superconducting states. For magnetically mediated pairing, similar result holds between $T<T_c$ and $T \geq T_c$, wh

Jian-Miin Liu

The relativistic equilibrium velocity distribution coincides with the Maxwellian distribution for small velocities and vanishes at c, the velocity of light. Based on the decay pattern of high-energy tail in the relativistic equilibrium velocity distribution, it is predicted for velocity and velocity rate distributions of astrophysical plasma particles that t

Michael Efroimsky

When a solid body is freely rotating at an angular velocity ${\bf Ω}$, the ellipsoid of constant angular momentum, in the space $Ω_1, Ω_2, Ω_3$, has poles corresponding to spinning about the minimal-inertia and maximal-inertia axes. The first pole may be considered stable if we neglect the inner dissipation, but becomes unstable if the dissipation is taken i

V. M. Kaspi, E. V. Gotthelf, B. M. Gaensler, M. Lyutikov

We report the first X-ray detection of the radio pulsar PSR B1757-24 using the Chandra X-ray Observatory. The image reveals point-source emission at the pulsar position, consistent with being magnetospheric emission from the pulsar. In addition, we detect a faint tail extending nearly 20&#34; east of the pulsar, in the same direction and with comparable morp

A. C. A. Boogert, M. R. Hogerheijde, G. A. Blake

We explore the infrared M band (4.7 um) spectrum of the class I protostar L1489 IRS in the Taurus Molecular Cloud. This is the highest resolution wide coverage spectrum at this wavelength of a low mass protostar observed to date (R=25,000; Dv=12 km/s). Many narrow absorption lines of gas phase 12CO, 13CO, and C18O are detected, as well as a prominent band of

Y. X. Feng, Wei Cui

We observed Cyg X-1 with {\em RXTE} contiguously over its 5.6-day binary orbit. The source was found to be in the hard state throughout the observation. Many intensity dips were detected in the X-ray light curves. We found that the dips fell into two distinct categories based on their spectral properties. One type exhibits strong energy-dependent attenuation

J. E. Horvath, G. Lugones, J. A. de Freitas Pacheco

We discuss the role of diquarks in constructing models of compact stars. These approaches are compared to recent claims of highly compact X-ray and isolated sources.

Arthur D. Chernin

Recent measurements of the cosmological constant or cosmic vacuum in Type Ia SN observations (Riess et al.1998, Perlmutter et al. 1999) imply that $Ω(t)$ is exactly unity or nearly unity at any epoch of cosmic evolution. No fine tuning is needed to describe this phenomenon with the standard cosmological model based on the Type Ia SN data. A time-independent

Douglas C. -J. Bock, Robert J. Sault, Douglas K. Milne, Anne J. Green

We present high-resolution 1.4 GHz Australia Telescope Compact Array polarimetric observations of Vela X, the pulsar wind nebula of the Vela SNR. We find that the linearly polarized emission is only partially correlated with total intensity. There are many depolarization features, some of which are coincident with foreground H-alpha filaments. Further study

Enrico Ramirez-Ruiz, Davide Lazzati, Andrew W. Blain

The physics of gamma-ray bursts (GRBs) and their offsets from the centers of their host galaxies are used to investigate the evolutionary state of their progenitors, motivated by the popular idea that GRBs are linked with the cataclysmic collapse of massive stars. We suggest that GRB progenitors in the inner and outer regions of hosts may be intrinsically di