November 2001 arXiv papers — page 7

Manfred P. Leubner

Increasing inhomogeneity due to gravitational clumping reflects increasing gravitational entropy in a time evolving universe. Starting from an ensemble of uniformly distributed particles it is demonstrated that gravitational clustering is subject to a specific quantization rule for the amount of increase of gravitational entropy during the formation of inhom

Mairi Sakellariadou

In this talk, I will illustrate how one can use the cosmic microwave background anisotropy measurements, in order to test theoretical models aiming at describing the early universe.

Konstantinos Dimopoulos

A unified approach to quintessence and inflation is investigated with the use of a single scalar field. It is argued that successful potentials have to approximate a combination of exponential and inverse power-law decline in the limit of large values of the scalar field. A class of such potentials is studied analytically and it is found that quintessential

L. Ballo, L. Maraschi, F. Tavecchio, A. Celotti

We present the BeppoSAX observations of 3C 279 performed in 1997 January 13-23 simultaneously with gamma-ray pointings with EGRET on board CGRO and optical observations at the Torino Observatory (1997 January 11-18). ISO data close to this epoch are also available. We compare the derived Spectral Energy Distribution with those obtained at all other epochs wi

D. Dallacasa, R. Falomo, C. Stanghellini

We present CCD observations of 13 objects from a complete sample of 55 bright High Frequency Peaker (HFP) radio sources, and provide optical identification for 12 of them. Images in R and V filters have been used to derive some additional information concerning the host of the radio source. Three hosts are likely to be galaxies, one resulted slightly extende

C. Done, P. T. Zycki, D. A. Smith

The spectra of disc accreting neutron stars generally show complex curvature, and individual components from the disc, boundary layer and neutron star surface cannot be uniquely identified. Here we show that much of the confusion over the spectral form derives from inadequate approximations for comptonization and for the iron line. There is an intrinsic low

Sebastien Lepine, Debra Wallace, Michael M. Shara, Anthony F. J. Moffat

We present spatially resolved spectra of the visual WR+OB massive binaries WR86, WR146, and WR147, obtained with the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope. The systems are classified as follows: WR86 = WC7 + B0 III, WR146 = WC6 + O8 I-IIf, WR147 = WN8 + O5-7 I-II(f). Both WR146 and WR147 are known to have strong non-thermal

S. Ehlerova, J. Palous

We discuss fragmentation processes which induce star formation in dense walls of expanding shells. The influence of the energy input, the ISM scale-height and speed of sound in the ambient medium is tested. We formulate the condition for the gravitational fragmentation of expanding shells: if the total surface density of the disc is higher than a certain cri

L. J. Greenhill, S. P. Ellingsen, R. P. Norris, P. J. McGregor

We report the cumulative results of five surveys for water maser emission at 1.35 cm wavelength in 131 active galactic nuclei (AGNs) and star-forming galaxies, conducted at the Parkes Observatory between 1993 and 1998. We detected one new maser, in the edge-on galaxy IRASF01063-8034, which exhibits a single, about 0.1 Jy spectral feature at 4282+/-6 km/s (he

P. G. Ananthasubramanian, Satoshi Yamamoto, Tushar P. Prabhu

We present 220 GHz (1.36 mm) measurements of zenith optical depth obtained to characterise the Indian Astronomical Observatory, Hanle (Ladakh, India) during the period from late December 1999 to early May 2000 and early October 2000 to September 2001. The data were sampled at an interval of 10 minutes. We describe the automated 220 GHz tipping radiometer use

Shinpei Shibata

We solve the one-dimensional Poisson equation along a magnetic field line, both analytically and numerically, for a given current density incorporating effects of returning positrons. We find that the number of returning positrons per one primary electrons should be smaller than unity, and the returning of positrons occurs only in a very short braking distan

Jill Bechtold, Adam Dobrzycki, Brenda Wilden, Miwa Morita

We analyzed the absorption line spectra of all quasars observed with the high resolution gratings of the Faint Object Spectrograph on board the Hubble Space Telescope. We examined 788 spectra for 334 quasars, and present line lists and identifications of absorption lines in the spectra of 271 of them. Analysis of the statistics of the Ly-alpha and metal abso

Pawel Pietrukowicz

Observations of Cepheids in the Large Magellanic Cloud, made over the last several decades, allow us to search for evolutionary period changes. None of the Cepheid from our sample of 378 stars stopped pulsating. Also none of them showed a large period change which could indicate mode switching. However for Cepheids with log P > 0.9 we found significant perio

Danny Calegari

We study the large-scale geometry of 3-manifolds with nontrivial 2-dimensional bounded cohomology, with a view to proving a weak version of the geometrization conjecture for such manifolds.

Hiroshi Ishikawa

We construct various boundary states in the coset conformal field theory G/H. The G/H theory admits the twisted boundary condition if the G theory has an outer automorphism of the horizontal subalgebra that induces an automorphism of the H theory. By introducing the notion of the brane identification and the brane selection rule, we show that the twisted bou

Thomas Schucker

We try to give a pedagogical introduction to Connes' derivation of the standard model of electro-magnetic, weak and strong forces from gravity.

C. Bernard

Chiral logarithms in $m_π^2$ are calculated at one loop, taking into account the leading contributions to flavor symmetry breaking due to staggered fermions. I treat both the full QCD case (2+1 light dynamical flavors) and the quenched case; finite volume corrections are included. My starting point is the effective chiral Lagrangian introduced by Lee and Sha

Arthur Kosowsky, Andrew Mack, Tinatin Kahniashvili

An injection of energy into the early Universe on a given characteristic length scale will result in turbulent motions of the primordial plasma. We calculate the stochastic background of gravitational radiation arising from a period of cosmological turbulence, using a simple model of isotropic Kolmogoroff turbulence produced in a cosmological phase transitio

S. F. King, D. A. J. Rayner

We consider twisted moduli contributions to supersymmetry breaking in effective type I string constructions involving intersecting D5_i and D9-branes using Goldstino angles to parametrise the supersymmetry breaking. It is well known that twisted moduli enter at tree-level into the gauge kinetic functions, and can provide new sources of gaugino mass if they d

A. Acin, T. Durt, N. Gisin, J. I. Latorre

Recently a new Bell inequality has been introduced (CGLMP,KKCZO) that is strongly resistant to noise for maximally entangled states of two $d$-dimensional quantum systems. We prove that a larger violation, or equivalently a stronger resistance to noise, is found for a non-maximally entangled state. It is shown that the resistance to noise is not a good measu

F. R. Klinkhamer

It is argued that a fundamental time asymmetry could arise from the global structure of the space manifold. The proposed mechanism relies on the CPT anomaly of certain chiral gauge theories defined over a multiply connected space manifold. The resulting time asymmetry (microscopic arrow of time) is illustrated by a simple thought experiment. The effect could

Mark Auslender, Eugene Kogan

We formulate the Dynamical Mean Field Approximation equations for the double-exchange system with quenched disorder for arbitrary relation between Hund exchange coupling and electron band width. Close to the ferromagnetic-paramagnetic transition point the DMFA equations can be reduced to the ordinary mean field equation of Curie-Weiss type. We solve the equa

R. M. Cavalcanti, P. Giacconi, G. Pupillo, R. Soldati

The behavior of an ideal $D$-dimensional boson gas in the presence of a uniform gravitational field is analyzed. It is explicitly shown that, contrarily to an old standing folklore, the three-dimensional gas does not undergo Bose-Einstein condensation at finite temperature. On the other hand, Bose-Einstein condensation occurs at $T\neq 0$ for $D=1,2,3$ if th

A. Deppeler, A. J. Millis

We use a recently developed formalism (combining an adiabatic expansion and dynamical mean-field theory) to obtain expressions for isotope effects on electronic properties in correlated systems. As an example we calculate the isotope effect on electron effective mass for the Holstein model as a function of electron-phonon interaction strength and doping. Our

Stefan Grosskinsky, Marc Timme, Bjoern Naundorf

We analyze a general class of reversible aggregate-reorganization processes. These processes are shown to exhibit globally attracting equilibrium distributions, which are \textit{universal}, i.e. identical for large classes of models. Furthermore, the analysis implies that for studies of equilibrium properties of \textit{any} such process, computationally ex

Rodolfo Gambini, Jorge Pullin

Starting from Ooguri's construction for $BF$ theory in three (and four) dimensions, we show how to construct a well defined theory with an infinite number of degrees of freedom. The spin network states that are kept invariant by the evolution operators of the theory are exact solutions of the Hamiltonian constraint of quantum gravity proposed by Thiemann

Ingo Kirsch, Djordje Sijacki

A generalization of the Dirac equation to the case of affine symmetry, with SL(4,R) replacing SO(1,3), is considered. A detailed analysis of a Dirac-type Poincare-covariant equation for any spin j is carried out, and the related general interlocking scheme fulfilling all physical requirements is established. Embedding of the corresponding Lorentz fields into

Johannes Berg, Silvio Franz, Mauro Sellitto

The Edwards hypothesis of ergodicity of blocked configurations for gently tapped granular materials is tested for abstract models of spin systems on random graphs and spin chains with kinetic constraints. The tapping dynamics is modeled by considering two distinct mechanisms of energy injection: thermal and random tapping. We find that ergodicity depends upo

Belle Collaboration, K. Abe

We present a measurement of the branching fraction for the semileptonic B decay Bbar -> D+l-nubar, where l- can be either an electron or a muon. We find Gamma(Bbar -> D+l-nubar)= (13.79+/-0.76+/-2.51) ns^{-1}, and the resulting branching fraction Br(Bbar -> D+l-nubar)= (2.13 +/- 0.12 +/- 0.39)%, where the first error is statistical and the second systematic.

G. Lazarides

The big bang model and the history of the early universe according to the grand unified theories are introduced. The shortcomings of big bang are discussed together with their resolution by inflationary cosmology. Inflation, the subsequent oscillation and decay of the inflaton, and the resulting "reheating" of the universe are studied. The density pe

Lorenzo Iorio

In this work some aspects of the detection of certain general relativistic effects in the weak gravitational field of the Earth via laser-ranged data to some existing or proposed geodetic satellites are examined. The focus is on the Lense-Thirring drag of the orbit of a test body, the gravitomagnetic clock effect and the gravitoelectric perigee shift. The im

Lajos Diosi, Claus Kiefer

We discuss the case of a Markovian master equation for an open system, as it is frequently found from environmental decoherence. We prove two theorems for the evolution of the quantum state. The first one states that for a generic initial state the corresponding Wigner function becomes strictly positive after a finite time has elapsed. The second one states

Wei Li, Yu Zhu, Tsung-han Lin

We present an analytical result for the supercurrent across a superconductor/quantum-dot/superconductor junction. By converting the current integration into a special contour integral, we can express the current as a sum of the residues of poles. These poles are real and give a natural definition of the Andreev bound states. We also use the exact result to e

Masahiro Kubo, C. S. Lim, Hiroyuki Yamashita

We pursue the possibility of the scenario in which the Higgs field is identified with the extra-space component of a bulk gauge field. The space-time we take is M$^{4}$ $\otimes$ S$^1$/Z$_2$. We show that a non-trivial Z$_2$-parity assignment allows some of the extra-space component to have radiatively induced VEV, which strongly modifies the mass spectrum a

K. Furukawa, N. Kamikubota, T. Suwada, T. Obata

In order to double the positron injection rate into the KEKB ring, a two-bunch acceleration scheme has been studied at the linac, in which bunches separated by 96 ns are accelerated in 50 Hz. In this scheme the stabilization of energy and orbit of each bunch is indispensable. Thus the beam energy and orbit feedback systems have been upgraded. Since beam char

John Ellis, Junji Hisano, Martti Raidal, Yasuhiro Shimizu

In the context of supersymmetric seesaw models of neutrino masses with non-degenerate heavy neutrinos, we show that Dirac Yukawa interactions N^c_i (Y_nu)_{ij} L_j H_2 induce large threshold corrections to the slepton soft masses via renormalization. While still yielding rates for lepton-flavour-violating processes below the experimental bounds, these contri

T. Djama

We establish the quantum stationary Hamilton-Jacobi equation in 3-D and its solutions for three symmetrical potentials, Cartesian symmetry potential, spherical symmetry potential and cylindrical symmetry potential. For the two last potentials, a new interpretation of the Spin is proposed within the framework of trajectory representation.

Ayman F. Abouraddy, Magued B. Nasr, Bahaa E. A. Saleh, Alexander V. Sergienko

We propose a new technique, called quantum optical coherence tomography (QOCT), for carrying out tomographic measurements with dispersion-cancelled resolution. The technique can also be used to extract the frequency-dependent refractive index of the medium. QOCT makes use of a two-photon interferometer in which a swept delay permits a coincidence interferogr

J. Allard, O. Jonsson, F. Locci, G. Mornacchi

In the context of the general consolidation of the CERN ISOLDE facility, a project has been started to upgrade the ISOLDE control system. We describe the new ISOLDE control system, emphasizing the systematic use of industrial components such as PLCs and field buses, their integration with the existing, VME based, CERN PS control system and their potential ap

D. Cheever, X. Geng

The Bates Linear Accelerator uses six 4MW 2.856GHz RF transmitters. Phase drifts between the transmitters 12 klystrons of greater than 0.5 degree or any amplitude drifts compromise beam delivery and are a common occurrence. Machine operators in years previous to the Phase and Amplitude Monitoring system "PAM" were unable to tell which klystron was af

Nikolai V. Erkaev, Vladimir S. Semenov, Ilya V. Alexeev, Helfried K. Biernat

The reconnection rate is obtained for the simplest case of 2D symmetric reconnection in an incompressible plasma. In the short note (Erkaev et al., Phys. Rev. Lett.,84, 1455 (2000)), the reconnection rate is found by matching the outer Petschek solution and the inner diffusion region solution. Here the details of the numerical simulation of the diffusion reg

Igor Goychuk, Peter Hänggi

The opening rate of voltage-gated potassium ion channels exhibits a characteristic, knee-like turnover where the common exponential voltage-dependence changes suddenly into a linear one. An explanation of this puzzling crossover is put forward in terms of a stochastic first passage time analysis. The theory predicts that the exponential voltage-dependence co

Arindam Mitra

It is widely believed that one signal can carry maximum one bit of information, and minimum KTlog2 energy is required to transmit or to erase a bit. Here it is shown four bits of information can be transmitted by one signal in four dimensional space-time. It implies space-time cannot be ignored to determine the minimal energy cost of information processing.

D. Mugnai

The motion of an electromagnetic wave, through a classically-forbidden region, has recently attracted renewed interest because of its implication with regard to the theoretical and experimental problems of superluminality. From an experimental point of view, many papers provide an evidence of superluminality in different physical systems. Theoretically, the

Alexander M. Ilyanok

A great number of macroquantum laws connecting gravity and electromagnetism if found empirically. To describe them the model of anisotropic gravitational field is proposed. This field is build as a superposition of planes and force lines are changed by thin elastic discs. Interaction of gravitational objects is described by second order linear differential e

Alexander M. Ilyanok

Quantum relativistic probability description of continuous world is re-examined. The new conception of physical world is offered. It is based on deterministic description of elementary particles, on conception The standard probability quantum relativistic picture of world is reviewed. The new picture of world is proposed. It is based on deterministic approac

R. M. Bryant, R. W. Carey, R. V. Claybourn, G. Pavel

This paper describes the requirements, design, and analysis of the control network for the National Ignition Facility (NIF). The network uses Ethernet technology throughout and ATM is used for efficient digital video transport.

Simone Chiesa, Massimo Mella, Gabriele Morosi

Exploiting an approach similar to the R-matrix theory, the diffusion Monte Carlo method is employed to compute phase shifts and threshold cross sections for the elastic scattering of o-positronium off light atoms. Results are obtained for Ps-H and Ps-He as representative cases of open and closed shell targets. The method allows for an exact treatment of both

P. Bracken, P. P. Goldstein, A. M. Grundland

The connection between the complex Sine and Sinh-Gordon equations on the complex plane associated with a Weierstrass type system and the possibility of construction of several classes of multivortex solutions is discussed in detail. We perform the Painlevé test and analyse the possibility of deriving the Bäcklund transformation from the singularity analysis

K. Weibert, J. Main, G. Wunner

A method is proposed for the calculation of diffusion constants for one-dimensional maps exhibiting deterministic diffusion. The procedure is based on harmonic inversion and uses a known relation between the diffusion constant and the periodic orbits of a map. The method is tested on an example map for which results calculated by different other techniques a

F. J. Castro-Jiménez, M. A. Moreno-Frías

This paper deals with the notion of Gröbner $δ$-base for some rings of linear differential operators by adapting the works of W. Trinks, A. Assi, M. Insa and F. Pauer. We compare this notion with the one of Gröbner base for such rings. As an application, and following a previous work of A. Assi, we give some results on finiteness and on flatness of finitely

Claude LeBrun

New estimates are derived concerning the behavior of self-dual hamonic 2-forms on a compact Riemannian 4-manifold with non-trivial Seiberg-Witten invariants. Applications include a vanishing theorem for certain Seiberg-Witten invariants on compact 4-manifolds of constant negative sectional curvature.

Narcisse Randrianantoanina

We prove that non-commutative martingale transforms are of weak type $(1,1)$. More precisely, there is an absolute constant $C$ such that if $\M$ is a semi-finite von Neumann algebra and $(\M_n)_{n=1}^\infty$ is an increasing filtration of von Neumann subalgebras of $\M$ then for any non-commutative martingale $x=(x_n)_{n=1}^\infty$ in $L^1(\M)$, adapted to

Lucía Fernández-Suárez, Antonio Gómez-Tato, Jeffrey Strom, Daniel Tanré

We show that the Lusternik-Schnirelmann category of the symplectic group Sp(3) is 5. This L-S category coincides with the cone length and the stable weak category.

Tsachik Gelander

We formulate a conjecture that arithmetic locally symmetric manifolds have simple homotopy type, and prove it for the non-compact case. More precisely, we show that, for any symmetric space S of non-compact type without Euclidean de Rham factors, there are constants a=a(S) and d=d(S) such that any non-compact arithmetic manifold, locally isometric to S, is h

Igor Yu. Potemine

We show that (quantum) D-modules of Givental type on affine flag varieties are transformed to D-modules of Beilinson-Drinfeld type on $n$-reduced Sato Grassmannians via affine Miura transformation.

Omegar Calvo, Vicente Munoz, Francisco Presas

We define the concept of symplectic foliation on a symplectic manifold and provide a method of constructing many examples, by using asymptotically holomorphic techniques.

V. Gutev, V. Valov

A characterization of $n$-dimensional spaces via continuous selections avoiding $Z_n$-sets is given, and a selection theorem for strongly countable-dimensional spaces is established. We apply these results to prove a generalized Ostrand's theorem and to obtain a new alternative proof of the Hurewicz formula.

Randall L. Rathbun

The original tables of body cuboids by Maurice Kraitchik are corrected, restoring 159 missing cuboids. His table range is then extended for all odd sides less than 1,000,000 to a new limit of 4,294,967,295. Over this new range, 12,517 unique body cuboids are listed, from the original 416.

Matti Pitkanen

Paper has been withdrawn due to an error in the basic argument that the states corresponding to the zeros of Riemann Zeta with Re[s]<1/2 allow a Fourier expansion in the basis provided by the states having Re[s]>= 1/2.

M. J. Duff

Current attempts to find a unified theory that would reconcile Einstein&#39;s General Relativity and Quantum Mechanics, and explain all known physical phenomena, invoke the Kaluza-Klein idea of extra spacetime dimensions. The best candidate is M-theory, which lives in eleven dimensions, the maximum allowed by supersymmetry of the elementary particles. We giv

Alexey Anisimov, Michael Dine, Michael Graesser, Scott Thomas

In brane world models of nature, supersymmetry breaking is often isolated on a distant brane in a higher dimensional space. The form of the Kahler potential in generic string and M-theory brane world backgrounds is shown to give rise to tree-level non-universal squark and slepton masses. This results from the exchange of bulk supergravity fields and warping

Daniel Kastler, Thomas Schucker

Our 1992 remarks about Alain Connes&#39; interpretation of the standard model within his theory of non-commutative riemannian spin manifolds.

D. Arnaudon, D. Karakhanyan, M. Mirumyan, A. Sedrakyan

We apply to the XYZ model the technique of construction of integrable models with staggered parameters, presented recently for the XXZ case. The solution of modified Yang-Baxter equations is found and the corresponding integrable zig-zag ladder Hamiltonian is calculated. The result is coinciding with the XXZ case in the appropriate limit.

Markus Luty, Raman Sundrum

We present a simple four-dimensional model in which anomaly mediated supersymmetry breaking naturally dominates. The central ingredient is that the hidden sector is near a strongly-coupled infrared fixed-point for several decades of energy below the Planck scale. Strong renormalization effects then sequester the hidden sector from the visible sector. Supersy

Dimitri Polyakov

Brane-like states are defined by physical vertex operators in NSR superstring theory, existing at nonzero pictures only. These states exist both in open and closed string theories, in the NS and NS-NS sectors respectively. In this paper we present a detailed analysis of their BRST properties, giving a proof that these vertex operators are physical, i.e. BRST

M. Moriconi

We discuss the new integrable boundary conditions for the O(N) nonlinear $σ$ model and related solutions of the boundary Yang-Baxter equation, which were presented in our previous paper hep-th/0108039.

Alakabha Datta, Harry J. Lipkin, Patrick J. O&#39;Donnell

The two body decays of $B_d$ and $B_s$ decays into $J/ψM$, where $M$ is a light meson, is studied under the very simple assumptions that the spectator quark does not play a role in the decay of the weak heavy quark or antiquark. This hypothesis leads to interesting relations between decay amplitudes. The assumption of SU(3) symmetry leads to additional relat

Rula Tabbash

This article is based on papers discussing different aspects of extra dimensional environments. In addition to the results, we review some of the concepts on which models with large extra dimensions are based.

Asmaa Abada, Sacha Davidson, Marta Losada

We analyse a simple RPV extension of the MSSM, with bilinear R-parity violation in the soft terms and vevs, but not between the terms in the superpotential. The model gives two massive neutrinos, and can fit all constraints from neutrino data. We show analytically how to compute the lepton number violating Lagrangian parameters from neutrino masses and mixin

A. V. Afanasev, I. Akushevich, N. P. Merenkov

The electron structure function method is applied to calculate model-independent radiative corrections to an asymmetry of electron-proton scattering. The representations for both spin-independent and spin-dependent parts of the cross-section are derived. Master formulae take into account the leading corrections in all orders and the main contribution of the

G. Fiorentini, F. L. Villante

We provide a method for extracting information on the energy spectrum of solar neutrinos directly from the spectrum of scattered electrons. As an example, we apply it to the published Super-Kamiokande data. When combined with data from SNO on charged current interactions this method allows to derive separately the spectra of nu_e and of nu_mu plus nu_tau.

B. Moussallam

Results are reviewed, which provide relations between the response (and eventual instability) of the chiral QCD vacuum to an increase of the number of massless quarks in the theory and the observed violations of the large $N_c$ expansion in the scalar meson sector, by combining chiral perturbation theory expansions in $m_s$ with sum rule methods. An approach

Raymond R. Volkas

Model-building issues raised by the prospect of light sterile neutrinos are discussed in a pedagogical way. I first review the na\&#34;ıve proposal that sterile neutrinos be identified with ``right handed neutrinos&#39;&#39;. A critical discussion of the simple expedient of adding three gauge singlet fermions to the usual minimal standard model matter conten

W. Q. Chao, C. S. Ju

The newly developed single trajectory quadrature method is applied to solve the ground state quantum wave function for Coulomb plus linear potential. The general analytic expressions of the energy and wave function for the ground state are given. The convergence of the solution is also discussed. The method is applied to the ground state of the heavy quarkon

Jiunn-Wei Chen, Martin J. Savage

We include the lowest-lying octet- and decuplet-baryons into partially quenched chiral perturbation theory. Perturbing about the chiral limit of the graded SU(6|3)_L x SU(6|3)_R flavor group of partially quenched QCD, we compute the leading one-loop contributions to the octet-baryon masses, magnetic moments and matrix elements of isovector twist-2 operators.

Kevin Stenson

Recent hadronic charm decay results from fixed-target experiments are presented. New measurements of the D0 to K-K+K-pi+ branching ratio are shown as are recent results from Dalitz plot fits to D+ to K-K+pi+, pi+pi-pi+, K-pi+pi+, K+pi-pi+ and D_s+ to pi+pi-pi+, K+pi-pi+. These fits include measurements of the masses and widths of several light resonances as

Zoltan Albrecht, Michael Feindt, Markus Moch, the DELPHI Collaboration

Analysis of the data shows that hadron tags of the two standard DELPHI particle identification packages RIBMEAN and HADSIGN are weakly correlated. This led to the idea of constructing a neural network for both kaon and proton identification using as input the existing tags from RIBMEAN and HADSIGN, as well as preproccessed TPC and RICH detector measurements

M. D. Iftime

Here we describe a stationary cylindrically symmetric solution of Einstein&#39;s equation with matter consisting of a positive cosmological and rotating dust term. The solution approaches Einstein static universe solution.

Yakov Itin

The coframe (teleparallel) description of gravity is known as a viable alternative to GR. One of advantages of this model is the existence of a conserved energy-momentum current witch is covariant under all symmetries of the three-parameter Lagrangian. In this paper we study the relation between the covector valued current and the energy-momentum tensor. Alg

J. M. Bardeen, L. T. Buchman

We investigate how the accuracy and stability of numerical relativity simulations of 1D colliding plane waves depends on choices of equation formulations, gauge conditions, boundary conditions, and numerical methods, all in the context of a first-order 3+1 approach to the Einstein equations, with basic variables some combination of first derivatives of the s

Sanjoy K. Sarker

We study metallic behavior and superconductivity in C$_{60}$ materials in terms of a tight binding model characterized by an intramolecular, nonretarded attraction. It was shown previously that, at intermediate coupling, the model possesees a state in which s-wave superconductivity coexists with a charge density wave, the latter stabilized by intersite repul

Adam Lipowski, Michel Droz

We introduce an urn model which describes spatial separation of sand. In this dynamical model, in a certain range of parameters spontaneous symmetry breaking takes place and equipartitioning of sand into two compartments is broken. The steady-state equation for an order parameter, a critical line, and the tricritical point on the phase diagram are found exac

V. Ya. Kravchenko

The paper has been permanently removed due to copyright issues.

Adam C. Durst, R. N. Bhatt, P. A. Wolff

The magnetic behavior of insulating doped diluted magnetic semiconductors (DMS) is characterized by the interaction of large collective spins known as bound magnetic polarons. Experimental measurements of the susceptibility of these materials have suggested that the polaron-polaron interaction is ferromagnetic, in contrast to the antiferromagnetic carrier-ca

A. Hewson, D. Meyer

We present numerical renormalization group (NRG) calculations for a single-impurity Anderson model with a linear coupling to a local phonon mode. We calculate dynamical response functions, spectral densities, dynamic charge and spin susceptibilities. Being non-perturbative, the NRG is applicable for all parameter regimes. Our calculations cover both weak and

A. D. Bochevarov, K. Ilyenko

We investigate theoretically perturbations to the confining potential capable of lifting spin degeneracy in axially symmetric quasi-one-dimensional electron gases with the spin-orbit interaction. The role of two different types of perturbations breaking axial symmetry of the system: of non-electromagnetic and electromagnetic origin is analyzed. We found that

Gerard Weisbuch, Guillaume Deffuant, Frederic Amblard, Jean Pierre Nadal

We present a model of opinion dynamics in which agents adjust continuous opinions as a result of random binary encounters whenever their difference in opinion is below a given threshold. High thresholds yield convergence of opinions towards an average opinion, whereas low thresholds result in several opinion clusters. The model is further generalised to netw

D. Bolle&#39;, P. Kozlowski

We study supervised learning and generalisation in coupled perceptrons trained on-line using two learning scenarios. In the first scenario the teacher and the student are independent networks and both are represented by an Ashkin-Teller perceptron. In the second scenario the student and the teacher are simple perceptrons but are coupled by an Ashkin-Teller t

R. Chughtai, V. Zhitomirsky, R. J. Nicholas, M. Henini

Measurements of the reflectivity of a 2-D electron gas are used to deduce the polarization of the Composite Fermion hole system formed for Landau level occupancies in the regime 1<ν<2. The measurements are consistent with the formation of a mixed spin CF system and allow the density of states or `polarization&#39; effective mass of the CF holes to be determi

Gerd Steinle-Neumann, Lars Stixrude, R. E. Cohen, Boris Kiefer

Experimental measurements of Raman spectra for hcp iron at high pressure show two modes over a considerable pressure range in contrast to the prediction of one doubly degenerate mode for the hcp lattice. We use density functional theory to investigate the influence of magnetic order on the Raman active modes of hcp iron. We find an antiferromagnetic state th

S. De Palo, S. Moroni, S. Baroni

We present quantum Monte Carlo calculations of total energy derivatives, consistently performed in the fixed-node approximation. Contributions from nodal displacements, neglected or approximated in previous investigations, are properly taken into account. Their impact on the efficiency is discussed.

V. M. Genkin

Current distribution for a thin superconducting strip shielded by two ideally conducting plains has been calculated. It is shown that at microwave requencies the current density has maximum over the center of the strip in contrast to the dc current pattern, which exhibits crowding over the edges.

P. Samuely, P. Szabo, J. Kacmarcik, A. G. M. Jansen

The temperature and angular dependencies of the resistive upper critical magnetic field $B_{c2}$ reveal a dimensional crossover of the superconducting state in the highly anisotropic misfit-layer single crystal of (LaSe)$_{1.14}$(NbSe$_2$) with the critical temperature $T_c$ of 1.23 K. The temperature dependence of the upper critical field $B_{c2\parallel ab

Eugene Gregoryanz, Alexander Goncharov, Russell J. Hemley, Ho-kwang Mao

We report the discovery of a new class of molecular phases of solid nitrogen at high pressures and temperatures by Raman and infrared spectroscopy and powder x-ray diffraction. Unlike the molecular phases consisting of disk- and sphere-like molecular disorder ($δ$-, $ε$- and $ζ$-N$_2$) and reportedly stable over a wide P-T range, one of the new phases ($ι$)

I. S. Queiroz, F. A. da Costa, F. D. Nobre

A p-spin interaction Ashkin-Teller spin glass, with three independent Gaussian probability distributions for the exchange interactions, is studied by means of the replica method. A simple phase diagram is obtained within the replica-symmetric approximation, presenting an instability of the paramagnetic solution at low temperatures. The replica-symmetry-break

T. Sekitani, M. Naito, H. Sato, N. Miura

We performed high-field magnetotransport experiments up to 50 T on strained La1.85Sr0.15CuO4 films. Two films with different strain, one expansively strained with Tc ~ 26 K and the other compressively strained with Tc ~ 44 K, show a striking contrast in the normal-state transport: the former has a prominent low-temperature upturn while the latter has not. Id

A. Krzywicki

The problem of defining a statistical ensemble of random graphs with an arbitrary connectivity distribution is discussed. Introducing such an ensemble is a step towards uderstanding the geometry of wide classes of graphs independently of any specific model. This research was triggered by the recent interest in the so-called scale-free networks.

Norbert S. Schulz, Claude R. Canizares, Julia C. Lee, Masao Sako

We present a first analysis of a high resolution X-ray spectrum of the ionized stellar wind of Vela X-1 during eclipse. The data were obtained with the High Energy Transmission Grating Spectrometer onboard the Chandra X-ray Observatory. The spectrum is resolved into emission lines with fluxes between 0.02 and 1.04x10^4 ph/cm^2/s. We identify lines from a var

Ioannis V. Sideris, Henry E. Kandrup

This paper continues a numerical investigation of orbits evolved in `frozen,&#39; time-independent N-body realisations of smooth time-independent density distributions corresponding to both integrable and nonintegrable potentials, allowing for N as large as 300,000. The principal focus is on distinguishing between, and quantifying, the effects of graininess