November 2005 arXiv papers — page 17

X. F. Sun, S. Ono, Yasushi Abe, Seiki Komiya

We report systematic, high-precision measurements of the low-T (down to 70 mK) thermal conductivity κof YBa_{2}Cu_{3}O_{y}, La_{2-x}Sr_{x}CuO_{4} and Bi_{2}Sr_{2}CaCu_{2}O_{8+δ}. Careful examinations of the Zn- and hole-doping dependences of the residual thermal conductivity κ_{0}/T, as well as the in-plane anisotropy of κ_{0}/T in Bi_{2}Sr_{2}CaCu_{2}O_{8+δ

Tsutomu Kobayashi, Takahiro Tanaka

We study the generation and evolution of gravitational waves (tensor perturbations) in the context of Randall-Sundrum braneworld cosmology. We assume that the initial and final stages of the background cosmological model are given by de Sitter and Minkowski phases, respectively, and they are connected smoothly by a radiation-dominated phase. This setup allow

T. Tatsumi, E. Nakano

Taking into account pseudoscalar as well as scalar condensates, we reexamine the chiral restoration path on the chiral manifold. We shall see both condensates coherently produce a density wave at a certain density, which delays chiral restoration as density or temperature is increased.

Edward E. Boos, Yuri S. Mikhailov, Mikhail N. Smolyakov, Igor P. Volobuev

We consider brane world models with interbrane separation stabilized by the Goldberger-Wise scalar field. For arbitrary background, or vacuum configurations of the gravitational and scalar fields in such models, we construct the second variation Lagrangian, study its gauge invariance, find the corresponding equations of motion and decouple them in a suitable

J. C. Hayes, M. L. Norman, R. A. Fiedler, J. O. Bordner

This paper describes ZEUS-MP, a multi-physics, massively parallel, message- passing implementation of the ZEUS code. ZEUS-MP differs significantly from the ZEUS-2D code, the ZEUS-3D code, and an early "version 1" of ZEUS-MP distributed publicly in 1999. ZEUS-MP offers an MHD algorithm better suited for multidimensional flows than the ZEUS-2D module by virtue

Fabio Antonio Bovino, Giuseppe Castagnoli, Artur Ekert, Pawel Horodecki

Non-linear properties of quantum states, such as entropy or entanglement, quantify important physical resources and are frequently used in quantum information science. They are usually calculated from a full description of a quantum state, even though they depend only on a small number parameters that specify the state. Here we extract a non-local and a non-

Patrick Bruno

A topological theory of the diabolical points (degeneracies) of quantum magnets is presented. Diabolical points are characterized by their diabolicity index, for which topological sum rules are derived. The paradox of the the missing diabolical points for Fe8 molecular magnets is clarified. A new method is also developed to provide a simple interpretation, i

Milos V. Lokajicek

There are three upper limits (2, 2.sqrt{2}, 2.sqrt{3}) of the Bell operator corresponding to different physical concepts: classical, hidden-variable and quantum-mechanical. Only the classical concept corresponding to the lowest limit has been excluded by experimental data, while the other two should be regarded as acceptable for the interpretation of EPR exp

Juergen Volz, Markus Weber, Daniel Schlenk, Wenjamin Rosenfeld

We report the observation of entanglement between a single trapped atom and a single photon at a wavelength suitable for low-loss communication over large distances, thereby achieving a crucial step towards long range quantum networks. To verify the entanglement we introduce a single atom state analysis. This technique is used for full state tomography of th

Raymond Laagel, Olivier Haeberlé

Serial and parallel combinations of diodes are studied by first establishing approached equivalence formulae. Sorting diodes enlights the true dispersion of their characteristics. This simple exercice helps students to realize that "identical" components may have in fact slightly different behaviour, especially in analogic electronic. Using very comm

Ekkehard Peik, Tobias Schneider, Christian Tamm

A fundamental limit to the stability of a single-ion optical frequency standard is set by quantum noise in the measurement of the internal state of the ion. We discuss how the interrogation sequence and the processing of the atomic resonance signal can be optimized in order to obtain the highest possible stability under realistic experimental conditions. A s

Emmanuel Friot, Régine Guillermin, Muriel Winninger

This paper presents an active noise control experiment designed to validate a real-time control strategy for reduction of the noise scattered from a three-dimensional body. The control algorithm relies on estimating the scattered noise by linear filtering of the total noise measured around the body; suitable filters are identified from off-line measurements.

Emmanuel Friot

Active cancellation of broadband random noise requires the detection of the incoming noise with some time advance. In an duct for example this advance must be larger than the delays in the secondary path from the control source to the error sensor. In this paper it is shown that, in some cases, the advance required for perfect noise cancellation is theoretic

N. Kolachevsky, J. Alnis, S. D. Bergeson, T. W. Haensch

We demonstrate a novel compact solid-state laser source for high-resolution two-photon spectroscopy of the $1S-2S$ transition in atomic hydrogen. The source emits up to 20 mW at 243 nm and consists of a 972 nm diode laser, a tapered amplifier, and two doubling stages. The diode laser is actively stabilized to a high-finesse cavity. We compare the new source

Yong Sun

In this work, the particle size distribution measured using the dynamic light scattering (DLS) technique is compared with that obtained from the static light scattering (SLS) technique or provided by the supplier measured using the Transmission Electron Microscopy (TEM) technique for dilute Poly($N$-isopropylacrylamide) microgel and standard polystyrene late

Yong Sun

In this work, three different particle sizes: the static radius $R_{s}$, hydrodynamic radius $R_{h}$ and apparent hydrodynamic radius $ R_{h,app}$ obtained using the light scattering technique, are investigated for dilute poly-disperse homogenous spherical particles with a simple assumption that the hydrodynamic radius is in proportion to the static radius,

Yong Sun

The new method proposed in this work not only measures the particle size distribution and the average molar mass accurately using the static light scattering (SLS) technique when the Rayleigh-Gans-Debye approximation is valid for dilute poly-disperse homogenous spherical particles in dispersion, but also enables us to have insight into the theoretical analys

John L. Haller

A computer code is written that simulates the relaxation back to thermal equilibrium of an ensemble of particles after a pi/2 pulse. Beginning with Bloch's equations the exponential relaxation behavior is discussed and the transition into a step by step process (from the continuous process) is made such that it is possible for the computer code to simula

Wang Hong-Yu, Huang Zu-Qia

This paper describe a numerical simulation method for the interaction between laser pulses and low density plasmas based on hydrodynamic approximation. We investigate Backward Raman Amplifying (BRA) experiments and their variants. The numerical results are in good agreement with experiments.

O. Manuel, Michael Mozina, Hilton Ratcliffe

Repulsive interactions between neutrons in compact stellar cores cause luminosity and a steady outflow of hydrogen from stellar surfaces. Neutron repulsion in more massive compact objects made by gravitational collapse produces violent, energetic, cosmological events (quasars, gamma ray bursts, and active galactic centers) that had been attributed to black h

N. Schunck, P. Olbratowski, J. Dudek, J. Dobaczewski

The three-dimensional cranking model is used to investigate the microscopic aspects of the rotation of nuclei with the tetrahedral symmetry. Two classes of rotation axes are studied corresponding to two different discrete symmetries of the rotating hamiltonian. Self-consistent Hartree-Fock-Bogoliubov calculations show that the tetrahedral minimum remains rem

C. Providencia, J. da Providencia, Y. Tsue, M. Yamamura

Following the basic idea developed in (I), the su(3)-model presented by Elliott is investigated. A method for constructing the orthogonal set, in which the angular momenta are good quantum numbers, is discussed without using the angular momentum projection.

C. Providencia, J. da Providencia, Y. Tsue, M. Yamamura

On the basis of the Schwinger boson representation for the Elliott model developed in (III), the Holstein-Primakoff representation for the su(3)-algebra is presented. The basic idea is the same as that adopted in (II), and as an example, the case of the lowest approximation is shown.

V. Greco, C. M. Ko

Using models ranging from schematic one with a simple quark distribution to more realistic blast wave, we study the elliptic flow of hadrons produced from coalescence of quarks and antiquarks in the quark-gluon plasma that is formed in ultrarelativistic heavy ion collisions. In particular, we study effects due to azimuthal anisotropy in the local transverse

J. T. Mitchell

The PHENIX Experiment at the Relativistic Heavy Ion Collider has made measurements of event-by-event fluctuations in the net charge, the mean transverse momentum, and the charged particle multiplicity as a function of collision energy, centrality, and transverse momentum in heavy ion collisions. The results of these measurements will be reviewed and discusse

J. Benlliure, E. Casarejos, J. Pereira, K. -H. Schmidt

Isotopic cross sections of all projectile residues with Z above 23 produced in collisions induced by 238U at 1 A GeV on deuterium have been measured. The isotopic distributions reflect the role of evaporation and fission in the formation process of these nuclei. The comparison of the measured cross sections with Monte-Carlo de-excitation codes including an a

Pantelis A. Damianou, Franco Magri

In this paper we propose a new algorithm for obtaining the rational integrals of the full Kostant-Toda lattice. This new approach is based on a reduction of a bi-Hamiltonian system on gl(n,R). This system was obtained by reducing the space of maps from Z_n to GL(n,R) endowed with a structure of a pair of Lie-algebroids.

Olga Yu. Efimova, Nikolai A. Kudryashov, Mikhail A. Chmykhov

The Burgers-Huxley equation is studied. All power and power-logarithmic expansions for travelling-wave solutions of this equation are presented. Using the power expansions, some exact solutions of this equation are found.

S. De Monte, F. d'Ovidio, H. Chate', E. Mosekilde

This paper studies the effect of independent additive noise on the synchronous dynamics of large populations of globally coupled maps. Our analysis is complementary to the approach taken by Teramae and Kuramoto [Teramae and Kuramoto, Phys. Rev. E 63:036210, 2001] who pointed out the anomalous scaling properties preceding the loss of coherence. We focus on th

Adrian Alexandrescu, Victor M. Perez-Garcia

We show how novel types of long-lived self-localized matter waves can be constructed with Bose-Einstein condensates. The ingredients leading to such structures are a spatial phase generating a flux of atoms towards the condensate center and the dissipative mechanism provided by the inelastic three-body collisions in atomic Bose-Einstein condensates. The outc

A. M. Grundland, B. Huard

In this paper we employ a "direct method" in order to obtain rank-k solutions of any hyperbolic system of first order quasilinear differential equations in many dimensions. We discuss in detail the necessary and sufficient conditions for existence of these type of solutions written in terms of Riemann invariants. The most important characteristic of

K. Graham

In this note we consider the ansatz for Multiple Schramm-Loewner Evolutions (SLEs) proposed by Bauer, Bernard and Kytola from a more probabilistic point of view. Here we show their ansatz is a consequence of conformal invariance, reparameterisation invariance and a notion of absolute continuity. In so doing we demonstrate that it is only consistent to grow m

N. I. Stoilova, J. Van der Jeugt

Para-Bose and para-Fermi statistics are known to be associated with representations of the Lie (super)algebras of class B. We develop a framework for the generalization of quantum statistics based on the Lie superalgebras A(m|n), B(m|n), C(n) and D(m|n).

V. Hinich

We prove that the Drinfeld double of the category of sheaves on an orbifold is equivalent to the category of sheves on the corresponding inertia orbifold.

Jose Burillo, Victor Guba

Let $F(p)$, $p\ge2$ be the family of generalized Thompson's groups. Here F(2) is the famous Richard Thompson's group usually denoted by $F$. We find the growth rate of the monoid of positive words in $F(p)$ and show that it does not exceed $p+1/2$. Also we describe new normal forms for elements of $F(p)$ and, using these forms, we find a lower bound

Adela Vraciu

We prove tight closure analogues of results of Watanabe about chains and families of integrally closed ideals.

Szilard Szabo

In this work we are concerned with reduction of the ASD-equations to the Riemann sphere, that is integrable connections with a harmonic metric, or equivalently Higgs bundles with a Hermitian-Einstein metric. In the first chapter, we introduce the type of singularities we allow for the solutions to have, and announce the main results of the paper. In the seco

E. Daems, A. B. J. Kuijlaars

We present a generalization of multiple orthogonal polynomials of type I and type II, which we call multiple orthogonal polynomials of mixed type. Some basic properties are formulated, and a Riemann-Hilbert problem for the multiple orthogonal polynomials of mixed type is given. We derive a Christoffel-Darboux formula for these polynomials using the solution

Tobias H. Colding, William P. Minicozzi

We give a quick tour through many of the classical results in the field of minimal submanifolds, starting at the definition. The field of minimal submanifolds remains extremely active and has very recently seen major developments that have solved many longstanding open problems and conjectures; for more on this, see the expanded version of this survey as wel

Igor Frenkel, Mikhail Khovanov, Catharina Stroppel

The purpose of this paper is to study categorifications of tensor products of finite dimensional modules for the quantum group for sl(2). The main categorification is obtained using certain Harish-Chandra bimodules for the complex Lie algebra gl(n). For the special case of simple modules we naturally deduce a categorification via modules over the cohomology

Eric Fusy

We completely solve the problem of enumerating combinatorially inequivalent $d$-dimensional polytopes with $d+3$ vertices. A first solution of this problem, by Lloyd, was published in 1970. But the obtained counting formula was not correct, as pointed out in the new edition of Grünbaum's book. We both correct the mistake of Lloyd and propose a more detai

Anne Broise, Frédéric Paulin

Given a tree $T$ and a group $\Ga$ of automorphisms of $T$, we study the markovian properties of the geodesic flow on the quotient by $\Ga$ of the space of geodesics of $T$. For instance, when $T$ is the Bruhat-Tits tree of a semi-simple connected algebraic group $\underline{G}$ of rank one over a non archimedian local field $\wh K$, and $\Ga$ is a (possibly

J. C Naranjo, G. P Pirola

We give a bound for the number of rational maps between algebraic varieties of general type under mild hypothesis on the canonical map. We use an idea inspired by Tanabe's work. Instead of attaching a morphism of Hodge structures to a rational map we simply associate to it a piece of the integral Hodge lattice. This procedure does not give an injective m

Joerg Winkelmann

We study non-Kaehler manifolds with trivial logarithmic tangent bundle. We show that each such manifold arises as a fiber bundle with a compact complex parallelizable manifold as basis and a toric variety as fiber.

Hans Lindblad

We show that a general class of quasilinear wave equations have global solutions for small initial data as we conjectured in an earlier paper.

Henry Cohn, Robert Kleinberg, Balazs Szegedy, Christopher Umans

We further develop the group-theoretic approach to fast matrix multiplication introduced by Cohn and Umans, and for the first time use it to derive algorithms asymptotically faster than the standard algorithm. We describe several families of wreath product groups that achieve matrix multiplication exponent less than 3, the asymptotically fastest of which ach

Herbert S. Wilf

We show that the probability that two permutations of $n$ letters have the same number of cycles is \[\sim \frac{1}{2\sqrt{π\log{n}}}.\]

Anne-Laure Basdevant

The fragmentation processes of exchangeable partitions have already been studied by several authors. In this paper, we examine rather fragmentation of exchangeable compositions, that means partitions of $\mathbb{N}$ where the order of the blocks counts. We will prove that such a fragmentation is bijectively associated to an interval fragmentation. Using this

Gestur Olafsson, Henrik Schlichtkrull

We study the heat equation associated to a multiplicity function on a root system, where the corresponding Laplace operator has been defined by Heckman and Opdam. In particular, we describe the image of the associated Segal-Bargmann transform as a space of holomorphic functions. In the case where the multiplicity function corresponds to a Riemannian symmetri

A. G. Ramm

This paper is withdrawn.

Yang Han, Yunge Xu

The minimal projective bimodule resolutions of the exterior algebras are explicitly constructed. They are applied to calculate the Hochschild (co)homology of the exterior algebras. Thus the cyclic homology of the exterior algebras can be calculated in case the underlying field is of characteristic zero. Moreover, the Hochschild cohomology rings of the exteri

Lars Winther Christensen, Srikanth Iyengar

Given a homomorphism of commutative noetherian rings R --> S and an S-module N, it is proved that the Gorenstein flat dimension of N over R, when finite, may be computed locally over S. When, in addition, the homomorphism is local and N is finitely generated over S, the Gorenstein flat dimension equals sup{m | Tor^R_m(E,N) \noteq 0} where E is the injective

Tobias H. Colding, William P. Minicozzi

In what follows we give a quick tour through the field of minimal submanifolds, starting at the definition and the classical results and ending up with current areas of research.

Francesca Aicardi, Vladlen Timorin

A quadratic form f is said to have semigroup property if its values at points of the integer lattice form a semigroup under multiplication. A problem of V. Arnold is to describe all binary integer quadratic forms with semigroup property. If there is an integer bilinear map s such that f(s(x,y))=f(x)f(y) for all vectors x and y from the integer 2-dimensional

Nathan Geer

For every semi-simple Lie algebra one can construct the Drinfeld-Jimbo algebra U. This algebra is a deformation Hopf algebra defined by generators and relations. To study the representation theory of U, Drinfeld used the KZ-equations to construct a quasi-Hopf algebra A. He proved that particular categories of modules over the algebras U and A are tensor equi

Andrew Baker, Birgit Richter

We discuss some of the basic ideas of Galois theory for commutative S-algebras originally formulated by John Rognes. We restrict attention to the case of finite Galois groups and to global Galois extensions. We describe parts of the general framework developed by Rognes. Central roles are played by the notion of strong duality and a trace mapping constructed

A. V. Ershov

In the present paper we study some homotopy invariants which can be defined by means of bundles with fiber a matrix algebra. We also introduce some generalization of the Brauer group in the topological context and show that any its element can be represented as a locally trivial bundle with a group of invertible operators in a Hilbert space as the structure

M. C. Diamantini, P. Sodano, C. A. Trugenberger

We propose a mechanism of superconductivity in which the order of the ground state does not arise from the usual Landau mechanism of spontaneous symmetry breaking but is rather of topological origin. The low-energy effective theory is formulated in terms of emerging gauge fields rather than a local order parameter and the ground state is degenerate on topolo

Alfio Bonanno, Giampiero Esposito, Claudio Rubano

Models of gravity with variable G and Lambda have acquired greater relevance after the recent evidence in favour of the Einstein theory being non-perturbatively renormalizable in the Weinberg sense. The present paper builds a modified Arnowitt-Deser-Misner (ADM) action functional for such models which leads to a power-law growth of the scale factor for pure

Hyeonjoon Shin, Kentaroh Yoshida

We briefly review our works for graviton and spherical graviton potentials in a plane-wave matrix model. To compute them, it is necessary to devise a configuration of the graviton solutions, since the plane-wave matrix model includes mass terms and hence the gravitons are not free particles as in the BFSS matrix model but harmonic oscillators or rotating par

G. A. Vilkovisky

Black holes create a vacuum matter charge to protect themselves from the quantum evaporation. A spherically symmetric black hole having initially no matter charges radiates away about 10% of the initial mass and comes to a state in which the vacuum-induced charge equals the remaining mass.

G. A. Vilkovisky

It has been shown in the previous paper that the metric in the semiclassical region of the collapse spacetime is expressed purely kinematically through the Bondi charges. Here the Bondi charges are expressed through this metric by calculating the vacuum radiation against its background. The result is closed equations for the metric and the Bondi charges. Not

G. A. Vilkovisky

The correspondence principle and causality divide the spacetime of a macroscopic collapsing mass into three regions: classical, semiclassical, and ultraviolet. The semiclassical region covers the entire evolution of the black hole from the macroscopic to the microscopic scale if the latter is reached. It is shown that the metric in the semiclassical region i

Nikolaos Kidonakis

I present a calculation of higher-order radiative corrections to charged Higgs production in association with a top quark via the process bg -> tH-. Results for charged Higgs production at the LHC are presented, including the dependence of the cross section on the charged Higgs mass, the top quark mass, the factorization and renormalization scales, and tan b

Mary K. Gaillard, Brent D. Nelson

We examine the phenomenological consequences of quadratically divergent contributions to the scalar potential in supergravity effective Lagrangians. We focus specifically on the effect of these corrections on the vacuum configuration of scalar fields in softly-broken supersymmetric theories and the role these corrections play in generating non-diagonal soft

S. Reucroft, Y. N. Srivastava, J. Swain, A. Widom

A consequence of the Higgs mechanism is that high mass particles, such as the Z-boson, the W-boson and the t-quark, are predicted to have masses that depend on the process by which they are produced. Thus, for example, particles produced singly are predicted to have higher masses than those produced in a pair near threshold. Quantitative details of this pred

Riccardo Abbate, Stefano Forte

We provide a determination of the Gottfried sum from all available data, based on a neural network parametrization of the nonsinglet structure function F_2. We find S_G=0.244 +- 0.045, closer to the quark model expectation S_G=1/3 than previous results. We show that the uncertainty from the small x region is somewhat underestimated in previous determinations

T. Marrodan Undagoitia, F. von Feilitzsch, M. Goeger-Neff, C. Grieb

The LENA (Low Energy Neutrino Astronomy) detector is proposed to be a large-volume liquid-scintillator device which will be highly suitable for the investigation of a variety of topics in astrophysics, geophysics and particle physics. In this paper, the potential of such a detector concerning the search for proton decay in the SUSY favored decay channel p->K

J. Arvieux, B. Collin, H. Guler, M. Morlet

QED radiative corrections have been calculated for leptonic and hadronic variables in parity-violating elastic ep scattering. For the first time, the calculation of the asymmetry in the elastic radiative tail is performed without the peaking-approximation assumption in hadronic variables configuration. A comparison with the PV-A4 data validates our approach.

S. Albino, B. A. Kniehl, G. Kramer, W. Ochs

An approach which unifies the Double Logarithmic Approximation at small x and the leading order DGLAP evolution of fragmentation functions at large x is presented. This approach reproduces exactly the Modified Leading Logarithm Approximation, but is more complete due to the degrees of freedom given to the quark sector and the inclusion of the fixed order ter

D. N. Triantafyllopoulos

We discuss the QCD evolution equations governing the high energy behavior of scattering amplitudes at the leading logarithmic level. This hierarchy of equations accommodates normal BFKL dynamics, Pomeron mergings and Pomeron splittings. Pomeron loops are built in the course of evolution and the scattering amplitudes satisfy the unitarity bound.

A. Bessa, E. S. Fraga

Assuming a first-order chiral transition scenario, we study the process of phase conversion driven by homogeneous nucleation. We adopt a quasiparticle model whose parameters are fit to lattice QCD data to describe the pressure at high temperature in the deconfined sector, and a bag model equation of state for pions in the low-temperature sector. We compute t

C. S. An, B. S. Zou, D. O. Riska

The implications of the empirical signatures for the positivity of the strangeness magnetic moment $μ_s$, and the negativity of the strangeness contribution to the proton spin $Δ_s$, on the possible $uuds\bar s$ configurations of five quarks in the proton are analyzed. The empirical signs for the values of these two observables can only be obtained in config

F. Gliozzi

The open Wilson lines are gauge-invariant operators made with a gauge transporter along an open path saturated at the end-points with matter fields. Here it is shown that numerical experiments on 3D Z2 Higgs model provide useful guidance in addressing the problem of the functional form of their vacuum expectation values. It turns out they satisfy, as long as

K. A. Bronnikov, J. C. Fabris

For self-gravitating, static, spherically symmetric, minimally coupled scalar fields with arbitrary potentials and negative kinetic energy (favored by the cosmological observations), we give a classification of possible regular solutions to the field equations with flat, de Sitter and AdS asymptotic behavior. Among the 16 presented classes of regular rsoluti

Martin Bojowald, Rafal Swiderski

Variables adapted to the quantum dynamics of spherically symmetric models are introduced, which further simplify the spherically symmetric volume operator and allow an explicit computation of all matrix elements of the Euclidean and Lorentzian Hamiltonian constraints. The construction fits completely into the general scheme available in loop quantum gravity

Songbai Chen, Jiliang Jing

Adopting the monodromy technique devised by Motl and Neitzke, we investigate analytically the asymptotic quasinormal frequencies of a coupled scalar field in the Gibbons-Maeda dilaton spacetime. We find that it is described by $ e^{βω}=-[1+2\cos{(\frac{\sqrt{2ξ+1}}{2} π)}]-e^{-β_I ω}[2+2\cos{(\frac{\sqrt{2ξ+1}}{2}π)}]$, which depends on the structure paramet

Silke Weinfurtner, Stefano Liberati, Matt Visser

So called "analogue models" use condensed matter systems (typically hydrodynamic) to set up an "effective metric" and to model curved-space quantum field theory in a physical system where all the microscopic degrees of freedom are well understood. Known analogue models typically lead to massless minimally coupled scalar fields. We present an

R. Hedjar, P. Boucher

The approximate nonlinear receding-horizon control law is used to treat the trajectory tracking control problem of rigid link robot manipulators. The derived nonlinear predictive law uses a quadratic performance index of the predicted tracking error and the predicted control effort. A key feature of this control law is that, for their implementation, there i

S. Heinrich, H. Durr, T. Hanel, J. Lassig

The goal is the development of a simultaneous, dynamic, technological as well as logistical real-time planning and an organizational control of the production by the production units themselves, working in the production network under the use of Multi-Agent-Technology. The design of the multi-agent-based manufacturing management system, the models of the sin

Dongqing He, Peisun Ma

It is very important for quadruped walking machine to keep its stability in high speed walking. It has been indicated that moment around the supporting diagonal line of quadruped in trotting gait largely influences walking stability. In this paper, moment around the supporting diagonal line of quadruped in trotting gait is modeled and its effects on body att

M. E. Torio, K. Hallberg, C. R. Proetto

The electronic properties and spectroscopic features of a magnetic trimer with a Kondo-like coupling to a non-magnetic metallic substrate are analyzed at zero temperature. The substrate density of states is depressed in the trimer neighbourhood, being exactly zero at the substrate chemical potential. The size of the resonance strongly depends on the magnetic

Steven H. Simon, Aris L. Moustakas

In a quantum dot with three leads the transmission matrix t_{12} between two of these leads is a truncation of a unitary scattering matrix S, which we treat as random. As the number of channels in the third lead is increased, the constraints from the symmetry of S become less stringent and t_{12} becomes closer to a matrix of complex Gaussian random numbers

Vladimir V. Talanov, Andre Scherz, Robert L. Moreland, Andrew R. Schwartz

We have developed a near-field scanned microwave probe with a sampling volume of approximately 10 micron in diameter, which is the smallest one achieved in near-field microwave microscopy. This volume is defined to confine close to 100 percent of the probe net sampling reactive energy, thus making the response virtually independent on the sample properties o

O. Chichigina, D. Valenti, B. Spagnolo

A noise source model, consisting of a pulse sequence at random times with memory, is presented. By varying the memory we can obtain variable randomness of the stochastic process. The delay time between pulses, i. e. the noise memory, produces different kinds of correlated noise ranging from white noise, without delay, to quasi-periodical process, with delay

Ansgar Esztermann, Hendrik Reich, Matthias Schmidt

A geometry-based density functional theory is presented for mixtures of hard spheres, hard needles and hard platelets; both the needles and the platelets are taken to be of vanishing thickness. Geometrical weight functions that are characteristic for each species are given and it is shown how convolutions of pairs of weight functions recover each Mayer bond

Uli Haeberle, Gregor Diezemann

We propose a dynamic Kerr effect experiment for the distinction between dynamic heterogeneous and homogeneous relaxation in glassy systems. The possibility of this distinction is due to the inherent nonlinearity of the Kerr effect signal. We model the slow reorientational molecular motion in supercooled liquids in terms of non-inertial rotational diffusion.

Irene D'Amico

We propose a quantum computer architecture based on quantum dots both for short distance and for long distance communication/computation. Our scheme exploits the natural characteristics of self-assembled quantum dots and it is scalable. It is centered on the idea of a quantum bus based on semiconductor self-assembled quantum dots. This allows for transmissio

A. V. Galaktionov, A. D. Zaikin

We analyze the effect of electron-electron interactions on Andreev current and shot noise in diffusive hybrid structures composed of a normal metal attached to a superconductor via a weakly transmitting interface. We demonstrate that at voltages/temperatures below the Thouless energy of a normal metal Coulomb interaction yields a reduction of both Andreev cu

Jizhong Lou, Changfeng Chen, Jize Zhao, Xiaoqun Wang

We study low-energy excitations in antiferromagnetic Heisenberg chains with a staggered field which splits the spectrum into a longitudinal and a transverse branch. Bound states are found to exist inside the field induced gap in both branches. They originate from the edge effects and are inherent to spin-chain materials. The sine-Gordon scaling $h_s^{2/3}|\l

J. Peguiron, M. Grifoni

Quantum Brownian motion in ratchet potentials is investigated by means of an approach based on a duality relation. This relation links the long-time dynamics in a tilted ratchet potential in the presence of dissipation with the one in a driven dissipative tight-binding model. The application to quantum ratchet yields a simple expression for the ratchet curre

M. D. Haw

We analyse structure and dynamics in simulated high-concentration hard sphere colloidal suspensions by means of calculations based on the void space. We show that remoteness, a quantity measuring the scale of spaces, is useful in studying crystallization, since ordering of the particles involves a change in the way empty space is distributed. Calculation of

Sabine Wurmehl, Gerhard H. Fecher, Vadim Ksenofontov, Frederick Casper

Co$_2$FeSi crystallizes in the ordered L2$_1$ structure as proved by X-ray diffraction and Mößbauer spectroscopy. The magnetic moment of Co$_2$FeSi was measured to be about $6μ_B$ at 5K. Magnetic circular dichroism spectra excited by soft X-rays (XMCD) were taken to determine the element specific magnetic moments of Co and Fe. The Curie temperature was measu

Sabine Wurmehl, Gerhard H. Fecher, Hem Chandra Kandpal, Vadim Ksenofontov

This work reports on structural and magnetic investigations of the Heusler compound Co$_2$FeSi. X-Ray diffraction and Mößbauer spectrometry indicate an ordered $L2_1$ structure. Magnetic measurements by means of X-ray magnetic circular dichroism and magnetometry revealed that this compound is, currently, the material with the highest magnetic moment ($6 μ_B$

V. Spicka, Th. M. Nieuwenhuizen, P. D. Keefe

This paper summarizes the recent state of the art of the following topics presented at the FQMT'04 conference: Quantum, mesoscopic and (partly) classical thermodynamics; Quantum limits to the second law of thermodynamics; Quantum measurement; Quantum decoherence and dephasing; Mesoscopic and nano-electro-mechanical systems; Classical molecular motors, ra

F. Carvalho Dias, I. R. Pimentel

We calculate the spin correlation function and the magnetic longitudinal and transverse susceptibilities of a two-dimensional antiferromagnet doped with a small concentration of holes, in the t-J model. We find that the motion of holes generates spin fluctuations which add to the quantum fluctuations, the spin correlations decaying with the inverse of the sp

Siddhartha Lal, Mukul S. Laad

Motivated by the co-existing charge and spin order found in strongly correlated ladder systems, we study an effective pseudospin model on a coupled two-leg ladder. A bosonisation analysis yields a rich phase diagram showing Wigner/Peierls charge order and Neel/dimer spin order. In a broad parameter regime, the orbital antiferromagnetic phase is found to be s

Soumendu Datta, Debasish Chaudhuri, Tanusri Saha-Dasgupta, Surajit Sengupta

We calculate the electrical conductivity of a thin crystalline strip of atoms confined within a quasi one dimensional channel of fixed width. The conductivity shows anomalous behavior as the strip is deformed under tensile loading. Beyond a critical strain, the solid fails by the nucleation of alternating bands of solid and {\em smectic} like phases accompan

Léonie Canet

This paper is devoted to investigating non-equilibrium phase transitions to an absorbing state, which are generically encountered in reaction-diffusion processes. It is a review, based on [Phys. Rev. Lett. 92, 195703; Phys. Rev. Lett. 92, 255703; Phys. Rev. Lett. 95, 100601], of recent progress in this field that has been allowed by a non-perturbative renorm

M. P. Singh, W. Prellier, L. Mechin, W. Prellier

A series of superlattices composed of ferromagnetic La$_{0.7}$Ca$_{0.3}$MnO$_3$ (LCMO) and ferroelectric/paraelectric Ba$_{1-x}$Sr$_x$TiO$_3$ (0$\leq $x$\leq $1) were deposited on SrTiO$_3$ substrates using the pulsed laser deposition. Films of epitaxial nature comprised of spherical mounds having uniform size are obtained. Magnetotransport properties of the