March 2001 arXiv papers — page 23

Philip Foth

The purpose of this note is to define tri-moment maps for certain manifolds that carry closed non-degenerate 4-forms and an $Sp(1)^n$-action. Examples include quaternionic vector spaces and flag manifolds. We show how this map can be used ro reduce such manifolds to the ones with fewer symmetries. The images of such maps for quaternionic flag manifolds, whic

Branislav K. Nikolic

In both research and textbook literature one often finds two ``different'' Kubo formulas for the zero-temperature conductance of a non-interacting Fermi system. They contain a trace of the product of velocity operators and single-particle (retarded and advanced) Green operators: $\text{Tr} (\hat{v}_x \hat{G}^r \hat{v}_x \hat{G}^a)$ or $\text{Tr} (\ha

A. Stoimenow

Using the band representation of the 3-strand braid group, it is shown that the genus of 3-braid links can be read off their skein polynomial. Some applications are given, in particular a simple proof of Morton's conjectured inequality and a condition to decide that some polynomials, like the one of 9_{49}, are not admitted by 3-braid links. Finally, alt

D. Bazeia, J. Menezes, M. M. Santos

We investigate bosonic sectors of supersymmetric field theories. We consider superpotentials described by one and by two real scalar fields, and we show how the equations of motion can be factorized into a family of first order Bogomol'nyi equations, so that all the topological defects are of the Bogomol'nyi-Prasad-Sommerfield type. We examine explic

Aykutlu Dâna, Charles Santori, Yoshihisa Yamamoto

Electrostatic force microscopy at cryogenic temperatures was used to probe the electrostatic interaction between a conductive atomic force microscopy tip and electronic charges trapped in an InAs quantum dot. Measurement of the self-oscillation frequency shift of the cantilever as a function of tip-sample bias voltage revealed discrete jumps at certain volta

Mikhail S. Plyushchay

We discuss the origin of the effectively free dynamics of the charge in the magnetic monopole field to apply it for finding the alternative treatment of the charge-monopole as a particle with spin, for tracing out the relation of the charge-monopole to the free relativistic anyon and for clarifying the nature of the non-standard nonlinear supersymmetry of th

H. -Th. Elze, J. Rafelski, L. Turko

The entropy production occurring in relativistic hydrodynamical systems such as the quark-gluon plasma (QGP) formed in high-energy nuclear collisions is explored. We study mechanisms which change the composition of the fluid, i.e. particle production and/or chemical reactions, along with chemo- and thermo-diffusion. These effects complement the conventional

J. A. Casas, A. Ibarra

If neutrino masses and mixings are suitable to explain the atmospheric and solar neutrino fluxes, this amounts to contributions to FCNC processes, in particular mu --> e, gamma. If the theory is supersymmetric and the origin of the masses is a see-saw mechanism, we show that the prediction for BR(mu --> e, gamma) is in general larger than the experimental up

S. Wakimoto, J. M. Tranquada, T. Ono, K. M. Kojima

Elastic neutron scattering measurements have been performed on Nd, Sr co-doped La1.55Nd0.4Sr0.05CuO4, which exhibits a structural phase transition at Ts ~ 60K from the low temperature orthorhombic Bmab phase (labelled LTO1) to the low temperature orthorhombic Pccn phase (labelled LTO2). At low temperatures, well below Ts, elastic magnetic peaks are observed

W. Pan, H. L. Stormer, D. C. Tsui, L. N. Pfeiffer

We study the ν=5/2 even-denominator fractional quantum Hall effect (FQHE) over a wide range of magnetic (B) field in a heterojunction insulated gate field-effect transistor (HIGFET). The electron density can be tuned from n=0 to 7.6 \times 10^{11} cm^{-2} with a peak mobility μ= 5.5 \times 10^6 cm^2/Vs. The ν=5/2 state shows a strong minimum in diagonal resi

Mikhail S. Volkov

The coupling to gravity in D=5 spacetime dimensions is considered for the particle-like and vortex-type solutions obtained by uplifting the D=4 Yang-Mills instantons and D=3 Yang-Mills-Higgs monopoles. It turns out that the particles become completely destroyed by gravity, while the vortices admit a rich spectrum of gravitating generalizations. Such vortex d

Ole Moeller, A. W. Blain

We discuss strong gravitational lensing by multiple objects along any line of sight. The probability for strong gravitational lensing by more than one lens is small, but a number of strong lens systems in which more than one separate lens contribute significantly to the lensing potential will be detected in the large sample of lens systems compiled with new

Glenn Starkman, Dejan Stojkovic, Tanmay Vachaspati

We analyze zero energy solutions of the Dirac equation in the background of a string-like configuration in an extension of the standard model which accommodates the most general fermionic mass matrix for neutrinos. If either the left- or the right-handed Majorana mass vanishes, neutrino and electron zero modes are found to exist. If the harmonic mean of the

R. Voituriez

We study random walks on the three-strand braid group $B_3$, and in particular compute the drift, or average topological complexity of a random braid, as well as the probability of trivial entanglement. These results involve the study of magnetic random walks on hyperbolic graphs (hyperbolic Harper-Hofstadter problem), what enables to build a faithful repres

Andreas Gross, Guillermo F. Rubilar

In the framework of metric-free electrodynamics, we start with a {\em linear} spacetime relation between the excitation 2-form $H = ({\cal D}, {\cal H})$ and the field strength 2-form $F = ({E,B})$. This linear relation is constrained by the so-called closure relation. We solve this system algebraically and extend a previous analysis such as to include also

D. A. Ivanov

The supersymmetric technique is applied to computing the average spectral density near zero energy in the large-N limit of the random-matrix ensembles with zero eigenvalues: B, DIII-odd, and the chiral ensembles (classes AIII, BDI, and CII). The supersymmetric calculations reproduce the existing results obtained by other methods. The effect of zero eigenvalu

M. Bordag, D. Vassilevich, H. Falomir, E. M. Santangelo

We propose the multiple reflection expansion as a tool for the calculation of heat kernel coefficients. As an example, we give the coefficients for a sphere as a finite sum over reflections, obtaining as a byproduct a relation between the coefficients for Dirichlet and Neumann boundary conditions. Further, we calculate the heat kernel coefficients for the mo

A. Delgado, M. Quirós

A five dimensional N=1 supersymmetric theory compactified on the orbifold $S^1/\mathbb{Z}_2$ is constructed. Gauge fields and $SU(2)_L$ singlets propagate in the bulk ($U$-states) while $SU(2)_L$ doublets are localized at an orbifold fixed point brane ($T$-states). Zero bulk modes and localized states constitute the MSSM and massive modes are arranged into N

Jihn E. Kim, Bumseok Kyae, Hyun Min Lee

The effective supersymmetric theory (ESUSY) with R parity conservation cannot give a large anomalous magnetic moment of $μ$. It is pointed out that the flavor conservation and a large $(g-2)_μ$ within the experimental limits are achievable in the ESUSY with R parity violating couplings involving the third generation superparticles.

Alexander Knebe, Ranty Islam, Joseph Silk

The evolution of the abundance of galaxy clusters is not a reliable measure of Omega if there are features on scales of a few Mpc in the primordial power spectrum. Conversely, if we know the cosmological model parameters from other measurements, the cluster abundance evolution permits us to probe features in the power spectrum that are in the nonlinear regim

Joris Lauwers, Andre Verbeure

We discuss metastable states in the mean-field version of the strong coupling BCS-model and study the evolution of a superconducting equilibrium state subjected to a dynamical semi-group with Lindblad generator in detailed balance w.r.t. another equilibrium state. The intermediate states are explicitly constructed and their stability properties are derived.

Ignatios Antoniadis, Savas Dimopoulos, Amit Giveon

We propose a framework where the string scale as well as all compact dimensions are at the electroweak scale $\sim$ TeV$^{-1}$. The weakness of gravity is attributed to the small value of the string coupling $g_s \sim 10^{-16}$, presumably a remnant of the dilaton's runaway behavior, suggesting the possibility of a common solution to the hierarchy and dilato

H. Nicolai, H. Samtleben

We present the maximally supersymmetric three-dimensional gauged supergravities. Owing to the special properties of three dimensions -- especially the on-shell duality between vector and scalar fields, and the purely topological character of (super)gravity -- they exhibit an even richer structure than the gauged supergravities in higher dimensions. The allow

Olindo Corradini, Zurab Kakushadze

We construct a solitonic 3-brane solution in the 6-dimensional Einstein-Hilbert-Gauss-Bonnet theory with a (negative) cosmological term. This solitonic brane world is delta-function-like. Near the brane the metric is that for a product of the 4-dimensional flat Minkowski space with a 2-dimensional ``wedge'' with a deficit angle (which depends on the

O. J. P. Eboli, M. B. Magro, P. Mathews, P. G. Mercadante

We analyze the potentiality of the new generation of $e^+e^-$ linear colliders to search for large extra dimensions via the production of fermion pairs in association with Kaluza-Klein gravitons (G), i.e. $e^+e^- \leftarrow f\bar{f}G$. This process leads to a final state exhibiting a significant amount of missing energy in addition to acoplanar lepton or jet

Wyn Evans, Francesc Ferrer, Subir Sarkar

Ultra-high energy cosmic rays (UHECRs) may originate from the decay of massive relic particles in the dark halo of the Galaxy, or they may be produced by supermassive black holes in the nuclei of nearby galaxies. The anisotropy in the arrival directions is studied in four dark halo models (cusped, isothermal, triaxial and tilted) and in four galaxy samples (

Saurabh Jha, Michael A. Pahre, Peter M. Garnavich, Michael L. Calkins

The gamma-ray burst (GRB) 010222 is the brightest GRB detected to date by the BeppoSAX satellite. Prompt identification of the associated optical transient (OT) allowed for spectroscopy with the Tillinghast 1.5m telescope at F. L. Whipple Observatory while the source was still relatively bright (R ~ 18.6 mag), within five hours of the burst. The OT shows a b

A. Hutton, S. Bose

We show that the amount of entanglement needed as an initial resource to set up a certain final amount of entanglement between two ends of a noisy channel can be reduced in certain cases by using quantum repeaters. Our investigation (for various channels) considers cases when a large number of entangled pairs are transmitted through the channel using known a

Dominik Janzing, Frederik Armknecht, Robert Zeier, Thomas Beth

In our model a fixed Hamiltonian acts on the joint Hilbert space of a quantum system and its controller. We show under which conditions measurements, state preparations, and unitary implementations on the system can be performed by quantum operations on the controller only. It turns out that a measurement of the observable A and an implementation of the one-

Dominik Janzing, Thomas Beth

If an experimentalist wants to decide which one of n possible Hamiltonians acting on an n dimensional Hilbert space is present, he can conjugate the time evolution by an appropriate sequence of known unitary transformations in such a way that the different Hamiltonians result in mutual orthogonal final states. We present a general scheme providing such a seq

Andrew M. Childs, Edward Farhi, Sam Gutmann

In this note, we discuss a general definition of quantum random walks on graphs and illustrate with a simple graph the possibility of very different behavior between a classical random walk and its quantum analogue. In this graph, propagation between a particular pair of nodes is exponentially faster in the quantum case.

Oscar Bolina, J. Rodrigo Parreira

Proof of a simple mathematical inequality using elements of surface tension theory and ideal gas law to the formation and coalescence of bubbles.

A. G. Borisov, J. P. Gauyacq, S. V. Shabanov

The electron transfer between an $F^{-}$ ion and $Cu(111)$ and $Ag(111)$ surfaces is studied by the wave packet propagation method in order to determine specifics of the charge transfer interaction between the negative ion and the metal surface due to the projected band gap. A new modeling of the $F^{-}$ ion is developed that allows one to take into account

L. Ingber, C. Chen, R. P. Mondescu, D. Muzzall

Motivated by path-integral numerical solutions of diffusion processes, PATHINT, we present a new tree algorithm, PATHTREE, which permits extremely fast accurate computation of probability distributions of a large class of general nonlinear diffusion processes.

D. J. Millener

Empirical data on the spectra of light hypernuclei, especially the data from recent gamma-ray experiments, is used to constrain the parameters which govern the p(nucleon)s(Lambda) and p(nucleon)p(Lambda) two-body matrix elements that enter into shell-model calculations.

Kenichiro Aoki, Dimitri Kusnezov

We examine the interplay of surface and volume effects in systems undergoing heat flow. In particular, we compute the thermal conductivity in the FPU $β$ model as a function of temperature and lattice size, and scaling arguments are used to provide analytic guidance. From this we show that boundary temperature jumps can be quantitatively understood, and that

Armando D'Anna, Gaetano Fiore

We consider initial-boundary-value problems for a class of nonlinear third order equations having non-autonomous forcing terms and get new asymptotic stability results by means of the Liapunov second method. The class includes equations arising in Superconductor Theory, Quantum Mechanics and in the Theory of Viscoelastic Materials.

P. Dita

Factorization of an $n\times n$ unitary matrix as a product of $n$ diagonal matrices containing only phases interlaced with $n-1$ orthogonal matrices each one generated by a real vector as well as an explicit form for the Weyl factorization are found.

P. Constantin, D. Cordoba, J. Wu

The 2D quasi-geostrophic (QG) equation is a two dimensional model of the 3D incompressible Euler equations. When dissipation is included in the model then solutions always exist if the dissipation's wave number dependence is super-linear. Below this critical power the dissipation appears to be insufficient. For instance, it is not known if the critical d

Eric Bedford, John Smillie

In this paper we use complex techniques to study the structure of real Henon diffeomorphisms of maximal topological entropy.

Eric Bedford, John Smillie

This paper continues our investigation of the dynamics of polynomial diffeomorphisms of C^2. We introduce a dynamical property of polynomial diffeomorphisms that generalizes hyperbolicity in the way that semi-hyperbolicity generalizes hyperbolicity for polynomial maps of the complex plane.

D. Drinen, M. Tomforde

K-theory and Ext are computed for the C*-algebra C*(E) of any countable directed graph E. The results generalize the K-theory computations of Raeburn and Szymanski and the Ext computations of Tomforde for row-finite graphs. As a consequence, it is shown that if A is a countable {0,1} matrix and E_A is the graph obtained by viewing A as a vertex matrix, then

Romuald Lenczewski

We introduce the filtered *-bialgebra which is a noncommutative analog of the *-bialgebra of multivariate polynomials with the canonical coproduct and counit. We study the associated filtered convolutions, random walks and random variables. The GNS representations of the limit states lead to filtered fundamental operators which are the CCR fundamental operat

Romuald Lenczewski

By introducing a color filtration to the multiplicity space, we extend the quantum Ito calculus on multiple symmetric Fock space to the framework of filtered adapted biprocesses. In this new notion of adaptedness,``classical'' time filtration makes the integrands similar to adapted processes, whereas ``quantum'' color filtration produces thei

Uwe Franz, Romuald Lenczewski

The central limit theorem, the invariance principle and the Poisson limit theorem for the hierarchy of freeness are studied. We show that for given natural m the limit laws can be expressed in terms of non-crossing partitions of depth smaller or equal to m. For the algebra of polynomials in one variable we solve the associated moment problems and find explic

Romuald Lenczewski

For a family of unital free *-algebras with a family of states on them, we construct a sequence of noncommutative probability spaces, which are tensor product algebras with tensor product states and which approximate the free product of states in the sense of convergence of mixed moments to those of free random variables. The constructed sequence of noncommu

Anatol N. Kirillov, Nadejda Liskova

For any rational number $p_0\ge 1$ we prove an identity of Rogers-Ramanujan-Gordon-Andrews' type. Bijection between the space of states for XXZ model and that of XXX model is constructed.

Eugene Lerman

We show that the cone associated with a moment map for an action of a torus on a contact compact connected manifold is a convex polyhedral cone and that the moment map has connected fibers provided the dimension of the torus is bigger than 2 and that no orbit is tangent to the contact distribution. This may be considered as a version of the Atiyah - Guillemi

S. Arkhipov, D. Gaitsgory

Let $G$ be an algebraic group and let $\widetilde{\mathfrak g}$ be the corresponding affine algebra on some level. Consider the induced module $V:=Ind^{\widetilde{\mathfrak g}}_{{\mathfrak g}[[t]](O_{G[[t]]})$, where $O_{G[[t]]}$ is the ring of regular functions on the group $G[[t]]$. In this paper we show that $V$ is naturally a vertex operator algebra, whi

Soon-Tae Hong, Won Tae Kim, John J. Oh, Young-Jai Park

We obtain (3+1) and (3+2) dimensional global flat embeddings of (2+1) uncharged and charged black strings, respectively. In particular, the charged black string, which is the dual solution of the Banados-Teitelboim-Zanelli black holes, is shown to be embedded in the same global embedding Minkowski space structure as that of the (2+1) charged de Sitter black

O. I. Vasilenko

We consider linearized 5-d gravity in the Randall-Sundrum brane world. The class of static solutions for linearized Einstein equations is found. Also we obtaine wave solutions describing radiation from an imaginary point source located at the Planck distance from the brane. We analyze the fields asymptotic behavior and peculiarities of matter sources.

M. Wellmann

This work deals with the theory of a quantized spin-2 field in the framework of causal perturbation theory. It is divided into two parts. In the first part we analyze the gauge structure of a massless self-interacting quantum tensor field. We look at this theory from a pure field theoretical point of view without assuming any geometrical aspect from general

Y. S. Myung

We prove the no-go theorem that the gravivector $(h_{5μ})$ and graviscalar $(h_{55})$ cannot have any on-shell propagation on the Randall-Sundrum (RS) brane. For this purpose, we analyze all of their linearized equations with the de Donder gauge (5D transverse-tracefree gauge). But we do not introduce any matter source. We use the Z$_2$-symmetry argument and

L. P. Colatto, A. L. A. Penna, C. M. M. Polito

We introduce a basis for a bi-dimensional finite matrix calculus and a bi-dimensional finite matrix action principle. As an application, we analyze scalar and spinorial fields in $D=4n+2$ in this approach. We verify that to establish a bi-dimensional matrix action principle we have to define a Dirac-algebra-modified Lebniz rule. From the bi-dimensional equat

Stephen P. Martin, James D. Wells

We study the muon anomalous magnetic dipole moment in supersymmetric theories. The impact of the recent Brookhaven E821 experimental measurement on both model-independent and model-dependent supersymmetric parameter spaces is discussed in detail. We find that values of tanβas low as 3 can be obtained while remaining within the E821 one-sigma bound. This requ

Sin Kyu Kang, Kang Young Lee

In the light of the recent measurement of the muon anmalous magnetic moment $a_μ$ by the Muon $(g-2)$ Collaboration, we examine the contribution to $a_μ$ from the exchange of flavor changing scalars. Assuming that the heavier generations have larger flavor changing couplings, we obtain a bound on $μ- τ$ Yukawa coupling for a given scalar mass. Constraints on

G. Colangelo, J. Gasser, H. Leutwyler

We show that, independently of the size of the quark condensate, chiral symmetry correlates the two S-wave ππscattering lengths. In view of this constraint, the new precision data on K_{e_4} decay allow a remarkably accurate determination of these quantities. The result confirms the hypothesis that the quark condensate is the leading order parameter.

H. V. Klapdor-Kleingrothaus, A. Dietz, L. Baudis, G. Heusser

New results for the double beta decay of 76Ge are presented. They are extracted from Data obtained with the HEIDELBERG-MOSCOW, which operates five enriched 76Ge detectors in an extreme low-level environment in the GRAN SASSO. The two neutrino accompanied double beta decay is evaluated for the first time for all five detectors with a statistical significance

Yu. S. Surovtsev, D. Krupa, M. Nagy

On the basis of a simultaneous description of the isoscalar s-wave of $ππ$ scattering (from the threshold up to 1.9 GeV) and of $ππ\to K\bar{K}$ process (from the threshold to $\sim$ 1.4 GeV) in the model-independent approach, it is shown that there exists the $f_0(665)$ state with properies of the $σ$-meson, the glueball nature of $f_0(1500)$ is indicated,

N. S. Amelin, N. Armesto, C. Pajares, D. Sousa

A Monte Carlo model to simulate nuclear collisions in the energy range going from SPS to LHC, is presented. The model includes in its initial stage both soft and semihard components, which lead to the formation of color strings. Collectivity is taken into account considering the possibility of strings in color representations higher than triplet or antitripl

A. Gashi, G. Rasche, W. S. Woolcock

We give a compact expression for the unpolarised differential cross section for muon-proton scattering in the one photon exchange approximation. The effect of adding the vacuum polarisation amplitude to the no-spin-flip amplitude for one photon exchange is calculated at small energies and scattering angles and is found to be negligible for present experiment

A. P. Kostyuk, M. I. Gorenstein, W. Greiner

We argue that the color deconfinement in heavy ion collisions may lead to enhanced production of hadrons with open heavy flavor (charm or bottom). We estimate the upper bound of this enhancement.

M. Klasen, G. Kramer

Differential cross sections for inclusive dijet photoproduction on a virtual pion have been calculated in next-to-leading order QCD as a function of $E_T, η$, and $x_π$. The cross sections are compared with recent ZEUS data on photoproduction of dijets with a leading neutron in the final state.

K. Sridhar

Virtual effects of gravitons in the production of diphotons at the upgraded Tevatron and at the LHC are analysed with the idea of probing the parameter space of the Randall-Sundrum (RS) model. It is shown that this process yields stringent constraints on the parameter space of the RS model. We show that data on diphoton production from Tevatron Run II will b

V. Barger

We consider the nu_mu to nu_e oscillation measurements that would be possible at upgraded 1 GeV and multi-GeV conventional neutrino sources driven by future megawatt-scale proton drivers. If these neutrino superbeams are used together with detectors that are an order of magnitude larger than those presently foreseen, we find that the sensitivity to nu_mu to

Yu. G. Kudenko

The recent progress in search for T-violating transverse muon polarization in the decays K^+ --> pi^0 mu^+ nu and K^+ --> mu^+ nu gamma in the on-going experiment E246 at KEK is reported. Future prospects in polarization measurements are also discussed.

Yakov Itin

The obstruction for the existence of an energy momentum tensor for the gravitational field is connected with differential-geometric features of the Riemannian manifold. It has not to be valid for alternative geometrical structures. In this article a general 3-parameter class of teleparallel models is considered. The field equation turns out to have a form co

Thoralf Chrobok, Yuri N. Obukhov, Mike Scherfner

A new solution for the stationary closed world with rigid rotation is obtained for the spinning fluid source. It is found that the spin and vorticity are locally balanced. This model qualitatively shows that the local rotation of the cosmological matter can be indeed related to the global cosmic vorticity, provided the total angular momentum of the closed wo

Nikolay Prokof'ev, Boris Svistunov, V. A. Kashurnikov

With a high-performance Monte Carlo algorithm we study the interaction-induced shift of the critical point in weakly interacting three-dimensional $|ψ|^4$-theory (which includes quantum Bose gas). In terms of critical density, $n_c$, mass, $m$, interaction, $U$, and temperature, $T$, this shift is universal: $Δn_c(T) = - C m^3 T^2 U$, the constant $C$ found

Luca Leuzzi, Theo M. Nieuwenhuizen

An analysis of the dynamics is performed, of exactly solvable models for fragile and strong glasses, exploiting the partitioning of the free energy landscape in inherent structures. The results are compared with the exact solution of the dynamics, by employing the formulation of an effective temperature used in literature. Also a new formulation is introduce

Nikolay Prokof'ev, Boris Svistunov

We show that high-temperature expansions may serve as a basis for the novel approach to efficient Monte Carlo simulations. "Worm" algorithms utilize the idea of updating closed path configurations (produced by high-temperature expansions) through the motion of end points of a disconnected path. An amazing result is that local, Metropolis-type schemes

Andrey K. Sarychev, Vladimir M. Shalaev

A first-principle theory for the effective dielectric permittivity in metallic mesostructures is developed. This theory, in particular, takes into account the skin effect, which is important in practical applications of metal structures.

Guillaume Ovarlez, Evelyne Kolb, Eric Clément

We study the rheology of a granular material slowly driven in a confined geometry. The motion is characterized by a steady sliding with a resistance force increasing with the driving velocity and the surrounding relative humidity. For lower driving velocities a transition to stick-slip motion occurs, exhibiting a blocking enhancement whith decreasing velocit

D. Marenduzzo, S. M. Bhattacharjee, A. Maritan, E. Orlandini

We report studies of the equilibrium and the dynamics of a general set of lattice models which capture the essence of the force-induced or mechanical DNA unzipping transition. Besides yielding the whole equilibrium phase diagram in the force vs temperature plane, which reveals the presence of an interesting re-entrant unzipping transition for low T, these mo

Alexander Quandt, Amy Y. Liu, Ihsan Boustani

Nanotubular materials inspired by crystalline diborides such as AlB_2 are proposed. The atomic structure, in particular the basic chemical question of where to put Al atoms in order to stabilize nanotubular Al-B systems, is investigated using density-functional calculations for prototype systems. The optimized tubular prototypes are found to be competitive i

Z. Burda, J. Jurkiewicz, M. A. Nowak, G. Papp

We suggest that Free Random Variables, represented here by large random matrices with spectral Levy disorder, may be relevant for several problems related to the modeling of financial systems. In particular, we consider a financial covariance matrix composed of asymmetric and free random Levy matrices. We derive an algebraic equation for the resolvent and so

M. Ausloos

Experimental studies of the electric and heat currents in the normal, superconducting and mixed states of high T$_c$ superconductors (HTcS) lead to characterization, complementary to data obtained from equilibrium property based techniques. A magnetic field superimposed on the superconducting sample generates {\it magneto-transport phenomena}, from which an

M. Ausloos, K. Durczewski, J. Ulner

The electrical resistivity, thermoelectric power and electronic thermal conductivity of simple (isotropic) metals are studied in a uniform way. Starting from results of a variational solution of the Boltzmann equation, a generalized Matthiessen rule is used in order to superpose the inelastic (or not) electron-phonon and elastic electron-impurity scattering

B. Zheng, H. J. Luo

With Monte Carlo simulations, we investigate short-time critical dynamics of the three-dimensional anti-ferromagnetic Ising model with a globally conserved magnetization $m_s$ (not the order parameter). From the power law behavior of the staggered magnetization (the order parameter), its second moment and the auto-correlation, we determine all static and dyn

J. Sadowski, R. Mathieu, P. Svedlindh, J. Z. Domagala

We have grown the ferromagnetic semiconductor GaMnAs containing up to 10% Mn by migration enhanced epitaxy at a substrate temperature of 150^oC. The alternate supply of As2 molecules and Ga and Mn atoms made it possible to grow single crystalline GaMnAs layers at very low substrate temperature, at which conventional molecular beam epitaxial growth under exce

B. Zheng

Taking the two-dimensional Ising model for example, short-time behavior of critical dynamics with a conserved order parameter is investigated by Monte Carlo simulations. Scaling behavior is observed, but the dynamic exponent $z$ is updating schemes dependent.

H. Arodz, R. Pelka, L. Stepien

Certain dissipative Ginzburg-Landau models predict existence of planar interfaces moving with constant velocity. In most cases the interface solutions are hard to obtain because pertinent evolution equations are nonlinear. We present a systematic perturbative expansion which allows us to compute effects of small terms added to the free energy functional of a

S. Correia

The mean free path is an essential characteristic length in disordered systems. In microscopic calculations, it is usually approximated by the classical value of the elastic mean free path. It corresponds to the Boltzmann mean free path when only isotropic scattering is considered, but it is different for anisotropic scattering. In this paper, we work out th

Z. Q. Pan, H. P. Ying, D. W. Gu

We present Monte Carlo simulation results of random-bond Potts ferromagnet with the Olson-Young self-dual distribution of quenched disorders in two-dimensions. By exploring the short-time scaling dynamics, we find universal power-law critical behavior of the magnetization and Binder cumulant at the critical point, and thus obtain estimates of the dynamic exp

B. Zheng, V. Linke, S. Trimper

Phase ordering dynamics of the (2+1)- and (3+1)-dimensional $ϕ^4$ theory with Hamiltonian equations of motion is investigated numerically. Dynamic scaling is confirmed. The dynamic exponent $z$ is different from that of the Ising model with dynamics of model A, while the exponent $λ$ is the same.

E. Lutz

We investigate fractional Brownian motion with a microscopic random-matrix model and introduce a fractional Langevin equation. We use the latter to study both sub- and superdiffusion of a free particle coupled to a fractal heat bath. We further compare fractional Brownian motion with the fractal time process. The respective mean-square displacements of these

P. D. Ye, L. W. Engel, D. C. Tsui, J. A. Simmons

We measure the high magnetic field ($B$) microwave conductivity, Re$σ_{xx}$, of a high mobility 2D electron system containing an antidot array. Re$σ_{xx}$ vs frequency ($f$) increases strongly in the regime of the fractional quantum Hall effect series, with Landau filling $1/3<ν<2/3$. At microwave $f$, Re$σ_{xx}$ vs $B$ exhibits a broad peak centered around

Felipe Barra, Benny Davidovitch, Anders Levermann, Itamar Procaccia

It had been conjectured that Diffusion Limited Aggregates and Laplacian Growth patterns (with small surface tension) are in the same universality class. Using iterated conformal maps we construct a 1-parameter family of fractal growth patterns with a continuously varying fractal dimension. This family can be used to bound the dimension of Laplacian Growth pa

Yu-Liang Liu

Using eigen-functional bosonization method, we study quantum many-particle systems, and show that the quantum many-particle problems end in to solve the differential equation of the phase fields which represent the particle correlation strength. Thus, the physical properties of these systems are completely determined by the differential equation of the phase

Sudha Srivastava, Shankar P. Das

The dynamics of Lennard-Jones fluid is studied through extended mode coupling theory (MCT) with the inclusion of the slow mode of defect density. Inclusion of defect density facilitates the liquid like state for temperatures much lower than predicted from ideal MCT. From the present model the temperature dependence of the power law exponent is obtained at a

Gabriel Tellez

We consider two-dimensional Coulomb systems confined in a disk with ideal dielectric boundaries. In particular we study the two-component plasma in detail. When the coulombic coupling constant $Γ=2$ the model is exactly solvable. We compute the grand-potential, densities and correlations. We show that the grand-potential has a universal logarithmic finite-si

Gregory Levine, V. N. Muthukumar

We study the dynamical properties of the Mermin model, a simple quantum dissipative model with a monochromatic environment, using analytical and numerical methods. Our numerical results show that the model exhibits a second order phase transition to a localized state before which the system is effectively decoupled from the environment. In contrast to the sp

Subir Sachdev, Matthias Troyer, Matthias Vojta

We compute the spectral function of a spin S hole injected into a two-dimensional antiferromagnet or superconductor in the vicinity of a magnetic quantum critical point. We show that, near van Hove singularities, the problem maps onto that of a static vacancy carrying excess spin S. The hole creation operator is characterized by a new boundary anomalous dime

S. D. Ryder, B. Koribalski, L. Staveley-Smith, V. Kilborn

We report the discovery, from the HI Parkes All-Sky Survey (HIPASS), of a gas cloud associated with the asymmetric spiral galaxy NGC 2442. This object, designated HIPASS J0731-69, contains ~10^9 M_sun of HI, or nearly one-third as much atomic gas as NGC 2442 itself. No optical counterpart to any part of HIPASS J0731-69 has yet been identified, consistent wit

R. J. White, A. M. Ghez

We present a high spatial resolution UV to NIR survey of 44 young binary stars in Taurus with separations of 10-1000 AU. The primary results include: (1) The relative ages of binary star components are more similar than the relative ages of randomly paired single stars, supporting coeval formation. (2) Only one of the companion masses is substellar, and henc

E. Kalemci, J. L. Matteson

We have investigated charge sharing among the anode strips of a CdZnTe (CZT) detector using a 30 micrometer collimated gamma-ray beam. We compared the laboratory measurements with the predictions from our modeling of the charge transport within the detector. The results indicate that charge sharing is a function of the interaction depth and the energy of the

T. A. Gardiner, A. Frank

Recent studies have focused on the the role of initially weak toroidal magnetic fields embedded in a stellar wind as the agent for collimation in planetary nebulae. In these models the wind is assumed to be permeated by a helical magnetic field in which the poloidal component falls off faster than the toroidal component. The collimation only occurs after the

M. Prakash, J. M. Lattimer, R. F. Sawyer, R. R. Volkas

Even the elusive neutrinos are trapped in matter, albeit transiently, in several astrophysical circumstances. Their interactions with the ambient matter not only reveal the properties of such exotic matter itself, but also shed light on the fundamental properties of the neutrinos themselves. The physical sites of interest include the early universe, supernov

Ben Moore

The hierarchical cold dark matter (CDM) model for structure formation is a well defined and testable model. Direct detection is the best technique for confirming the model yet predictions for the energy and density distribution of particles on earth remain inadequate. Axially symmetric collapse of collisionless dark matter can leave observable caustic rings

A. J. Benson, C. S. Frenk, C. M. Baugh, S. Cole

We follow the evolution of the galaxy population in a Lambda-CDM cosmology by means of high-resolution N-body simulations in which the formation of galaxies and their observable properties are calculated using a semi-analytic model. We display images of the spatial distribution of galaxies in the simulations that illustrate its evolution and provide a qualit