December 2001 arXiv papers — page 26

Ilia Gogoladze, Abdel Pérez-Lorenzana

We suggest that many of the free parameters in the supersymmetric extensions of the Standard Model can be all linked together to the existence of a non universal U(1) gauge symmetry, which has been spontaneously broken at very high scale. Such a symmetry can easily generate, via non-renormalizable operators, appropriate tree level fermion mass textures as we

Stanislaw Mrowczynski

Various measures of charge fluctuations in heavy-ion collisions are discussed. Advantages of the Phi-measure are demonstrated and its relation to other fluctuation measures is established. To get the relation, Phi is expressed through the moments of multiplicity distribution. We study how the measures act in the case of a `background' model which represe

P. Norberg, C. M. Baugh, E. Hawkins, S. Maddox

We investigate the dependence of galaxy clustering on luminosity and spectral type using the 2dF Galaxy Redshift Survey (2dFGRS). Spectral types are assigned using the principal component analysis of Madgwick et al. We divide the sample into two broad spectral classes: galaxies with strong emission lines (`late-types'), and more quiescent galaxies (`earl

M. Bradac, P. Schneider, M. Steinmetz, M. Lombardi

In this work we investigate the gravitationally lensed system B1422+231. High--quality VLBI image positions, fluxes and shapes as well as an optical HST lens galaxy position are used. First, two simple and smooth models for the lens galaxy are applied to fit observed image positions and fluxes; no even remotely acceptable model was found. Such models also do

F. La Barbera, G. Busarello, P. Merluzzi, M. Massarotti

Structural parameters (half-light radius $r_e$, mean effective surface brightness $<μ>_e$, and Sersic index n) are derived for a sample of galaxies in the rich cluster AC 118 at z=0.31: so far the largest (N=93) sample of galaxies at intermediate-redshift with structural parameters measured in the near-infrared. The parameters are obtained in two optical wav

Michael Nauenberg

We present a novel numerical method to calculate periodic orbits for dynamical systems by an iterative process which is based directly on the action integral in classical mechanics. New solutions are obtained for the planar motion of three equal mass particles on a common periodic orbit with finite total angular momentum, under the action of attractive pairw

Albert Reiner, Gerhard Kahl

Combining renormalization group theoretical ideas with the integral equation approach to fluid structure and thermodynamics, the Hierarchical Reference Theory is known to be successful even in the vicinity of the critical point and for sub-critical temperatures. We here present a software package independent of earlier programs for the application of this th

A. Bagrets, C. Lacroix, A. Vedyayev

We present a microscopic theory of proximity effect in the ferromagnet/superconductor/ferromagnet (F/S/F) nanostructures where S is s-wave low-T_c superconductor and F&#39;s are layers of 3d transition ferromagnetic metal. Our approach is based on the solution of Gor&#39;kov equations for the normal and anomalous Green&#39;s functions together with a self-co

J. Kempe, K. B. Whaley

In a previous publication [1] we showed that it is possible to implement universal quantum computation with the anisotropic XY-Heisenberg exchange acting as a single interaction. To achieve this we used encodings of the states of the computation into a larger Hilbert space. This proof is non- constructive, however, and did not explicitly give the trade-offs

Hagen Kleinert, Flavio S. Nogueira

We point out interesting effects of additional massless Dirac fermions with N_F colors upon the critical behavior of the Ginzburg-Landau model. For increasing N_F, the model is driven into the type II regime of superconductivity. The critical exponents are given as a function of N_F.

Wujun Huo, Xinmin Zhang, Tao Huang

Recently BES at BEPC found evidence for the existence of the $σ$ meson in the process of $J/Ψ\to σω\toππω$. In this paper we firstly discuss the relevant coupling $g_{σππ}$ and show that the linear $σ$ model gives rise to a reasonable description of the $σ$ decay into $π$&#39;s, then we calculate the coupling constant $g^{th}_{J/Ψσω}$ by using the perturbati

G. Giachetta, L. Mangiarotti, G. Sardanashvily

Quantum systems with adiabatic classical parameters are widely studied, e.g., in the modern holonomic quantum computation. We here provide complete geometric quantization of a Hamiltonian system with time-dependent parameters, without the adiabatic assumption. A Hamiltonian of such a system is affine in the temporal derivative of parameter functions. This le

Martin Rivas

We obtain by invariance arguments the relativistic and non-relativistic invariant dynamical equations of a classical model of a spinning electron. We apply the formalism to a particular classical model which satisfies Dirac&#39;s equation when quantised. It is shown that the dynamics can be described in terms of the evolution of the point charge which satisf

Ewa L. Lokas

We study the distribution of dark matter in dwarf spheroidal galaxies by modelling the moments of their line-of-sight velocity distributions. We discuss different dark matter density profiles, both cuspy and possessing flat density cores. The predictions are made in the framework of standard dynamical theory of two-component (stars and dark matter) spherical

Hideaki Kudoh, Takahiro Tanaka

The nonlinear gravitational interaction is investigated in the Randall-Sundrum two branes model with the radius stabilization mechanism. As the stabilization model, we assume a single scalar field that has a potential in the bulk and a potential on each brane. We develop a formulation of the second order gravitational perturbations under the assumption of a

A. K. Giri, R. Mohanta, M. P. Khanna

We note that it is possible to determine the weak phase γfrom the time dependent measurements of the decays $B_s^0(t) (\bar B_s^0 (t)) \to \bar D^0 ϕwithout any hadronic uncertainties. These decays are described by the color suppressed tree diagrams and hence are free from the penguin pollutions. We further demonstrate that γcan also be extracted with no had

Ashok Muthukrishnan, C. R. Stroud

We propose an implementation of the quantum fast Fourier transform algorithm in an entangled system of multilevel atoms. The Fourier transform occurs naturally in the unitary time evolution of energy eigenstates and is used to define an alternate wave-packet basis for quantum information in the atom. A change of basis from energy levels to wave packets amoun

V. G. Bagrov, J. C. A. Barata, D. M. Gitman, W. F. Wreszinski

The dynamics of two-level systems in time-dependent backgrounds is under consideration. We present some new exact solutions in special backgrounds decaying in time. On the other hand, following ideas of Feynman, Vernon and Hellwarth, we discuss in detail the possibility to reduce the quantum dynamics to a classical Hamiltonian system. This, in particular, op

Jan Bouda, Vladimir Buzek

We prove that all purifications of a non-factorable state (i.e., the state which cannot be expressed in a form $ρ_{AB}=ρ_A\otimesρ_B$) are entangled. We also show that for any bipartite state there exists a pair of measurements which are correlated on this state if and only if the state is non-factorable.

J. Kempe, D. Bacon, D. P. DiVincenzo, K. B. Whaley

We present a theoretical analysis of the paradigm of encoded universality, using a Lie algebraic analysis to derive specific conditions under which physical interactions can provide universality. We discuss the significance of the tensor product structure in the quantum circuit model and use this to define the conjoining of encoded qudits. The construction o

Frank Verstraete, Michael M. Wolf

We discuss the relations between the violation of the CHSH Bell inequality for systems of two qubits on the one side and entanglement of formation, local filtering operations, and the entropy and purity on the other. We calculate the extremal Bell violations for a given amount of entanglement of formation and characterize the respective states, which turn ou

T. Masuda, T. Fukui, R. Tanaka, A. Yamashita

The SPring-8 control system provides data acquisition software called Poller/Collector for periodic data taking. Its polling scheme does not support taking data synchronized with an event, and simultaneity in the data from the different VME systems is not guaranteed. Recently, requirement for fast and event-driven data acquisition has increased, and the sync

P. Danielewicz

Nuclear equation of state plays an important role in the evolution of the Universe, in supernova explosions and, thus, in the production of heavy elements, and in stability of neutron stars. The equation constrains the two- and three-nucleon interactions and the quantum chromodynamics in nonperturbative regime. Despite the importance of the equation, though,

V. A. Karmanov, J. Carbonell, M. Mangin-Brinet

We develop a general method to construct two relativistic fermions bound states with a given $J^π$, in the framework of the explicitly covariant light-front dynamics.

M. Baldo, U. Lombardo, E. E. Saperstein, M. V. Zverev

A realistic model is suggested based on the quasiparticle Lagrange version of the self-consistent Finite Fermi Systems theory supplemented with the microscopically calculated surface parameters of the Landau-Migdal interaction amplitude. The latter are expressed in terms of the off-shell T-matrix of free NN-scattering and show a strong dependence on the chem

Piotr Magierski, Aurel Bulgac, Paul-Henri Heenen

In the present study we investigate the static properties of nuclei in the inner crust of neutron stars. Using the Hartree-Fock method in coordinate space, together with the semiclassical approximation, we examine the patterns of phase transitions.

Piotr Magierski, Aurel Bulgac, Paul-Henri Heenen

The inner crust of neutron stars consists of nuclei of various shapes immersed in a neutron gas and stabilized by the Coulomb interaction in the form of a crystal lattice. The scattering of neutrons on nuclear inhomegeneities leads to the quantum correction to the total energy of the system. This correction resembles the Casimir energy and turns out to have

D. H. Lu, A. W. Thomas, K. Tsushima

We study the modification of the nucleon axial form factor in nuclear matter. The internal quark substructure of the nucleon is self-consistently described by the quark meson coupling model. We find that the axial form factor of the bound nucleon is quenched considerably from that of the free nucleon. The axial vector coupling constant is reduced by roughly

Gonzalo Izus, Maxi San Miguel, Daniel Walgraef

We study the role of a direct intracavity polarization coupling in the dynamics of transverse pattern formation in type-II optical parametric oscillators. Transverse intensity patterns are predicted from a stability analysis, numerically observed, and described in terms of amplitude equations. Standing wave intensity patterns for the two polarization compone

Yaoming Shi, W. M. McClain, J. E. Hearst

In previous work, the dynamics of the elastic rod was recast in a Lax pair formulation, with fiducial arc length s and time t as continuous independent variables. However, the solution of these equations cannot apply directly to a system where the fiducial arc length s is a discrete variable. In this paper, we show how to discretize the continuous s variable

F. Finkel, A. S. Fokas

A method for constructing evolution equations admitting a master symmetry is proposed. Several examples illustrating the method are presented. It is also noted that for certain evolution equations master symmetries can be useful for obtaining new conservation laws from a given one.

A. H. Vartanian

The methodology of the Riemann-Hilbert (RH) factorisation approach for Lax-pair isospectral deformations is used to derive, in the solitonless sector, the leading-order asymptotics as $t \to \pm \infty$ $(x/t \sim \mathcal{O}(1))$ of solutions to the Cauchy problem for the defocusing non-linear Schrödinger equation (D${}_{f}$NLSE), $\mi \partial_{t}u +\parti

Andre J. Starobin, Stephen W. Teitsworth

We report the first direct experimental observation of scarring phenomenon in transverse vibrational modes of a thin metal plate. The plate has the shape of a full stadium and clamped boundary conditions. Normal modes are imaged using time-averaged holographic interferometry, and modes corresponding to ``bouncing ball&#39;&#39; and higher order periodic traj

M. Shcherbina, B. Tirozzi

We prove rigorously the well-known result of Gardner about the typical fractional volume of interactions between N spins which solve the problem of storing a given set of random patterns. The Gardner formula for this volume in the limit N,p \to \infty, p/N \to αis proven for all values of α. Besides, we prove a useful criterion of the factorisation of all th

Evgueni Tevelev

This text is a draft of the review paper on projectively dual varieties. Topics include dual varieties, Pyasetskii pairing, discriminant complexes, resultants and schemes of zeros, secant and tangential varieties, Ein theorems, applications of projective differential geometry and Mori theory to dual varieties, degree and multiplicities of discriminants, self

J. Scott Carter, Masahico Saito

This paper is a survey of several papers in quandle homology theory and cocycle knot invariants that have been published recently. Here we describe cocycle knot invariants that are defined in a state-sum form, quandle homology, and methods of constructing non-trivial cohomology classes.

Konstanze Rietsch

We show that the set of totally positive unipotent lower-triangular Toeplitz matrices in $GL_n$ form a real semi-algebraic cell of dimension $n-1$. Furthermore we prove a natural cell decomposition for its closure. The proof uses properties of the quantum cohomology rings of the partial flag varieties of $GL_n(\C)$ relying in particular on the positivity of

Naichung Conan Leung, Tom Yau-heng Wan

We study the topology of a complete asymptotically hyperbolic Einstein manifold such that its conformal boundary has positive Yamabe invariant. We proved that all maps from such manifold into any nonpositively curved manifold are homotopically trivial. Our proof is based on a Bochner type argument on harmonic maps.

Konstanze Rietsch

We give a proof of a result of D. Peterson&#39;s identifying the quantum cohomology ring of a Grassmannian with the reduced coordinate ring of a certain subvariety of $GL_n$. The totally positive part of this subvariety is then constructed and we give closed formulas for the values of the Schubert basis elements on the totally positive points. We then use th

Eduardo D. Sontag

A notion of &#34;asymptotic Cauchy gain&#34; for input/output systems, and an associated small-gain principle, are introduced. A Lyapunov-like characterization allows the computation of these gains for state-space systems, and the formulation of sufficient conditions insuring the lack of oscillations and chaotic behaviors in a wide variety of cascades and fe

Daniel Azagra, Manuel Cepedello Boiso

We prove that every continuous function on a separable infinite-dimensional Hilbert space X can be uniformly approximated by smooth functions with no critical points. This kind of result can be regarded as a sort of very strong approximate version of the Morse-Sard theorem. Some consequences of the main theorem are as follows. Every two disjoint closed subse

Romuald Lenczewski

We introduce and study noncommutative extensions of the Fourier transform and its logarithm to the algebra of functions on the free semigroup FS(2) on two generators with the convolution multiplication. These extensions are new types of moment and cumulant generating functions, respectively, the latter corresponding to the cumulants which are additive under

T. Mansour

Following Mansour, let $S_n^{(r)}$ be the set of all coloured permutations on the symbols $1,2,...,n$ with colours $1,2,...,r$, which is the analogous of the symmetric group when r=1, and the hyperoctahedral group when r=2. Let $I\subseteq\{1,2,...,r\}$ be subset of d colours; we define $T_{k,r}^m(I)$ be the set of all coloured permutations $ϕ\in S_k^{(r)}$

Eitan Tadmor, Jared Tanner

We discuss the reconstruction of piecewise smooth data from its (pseudo-) spectral information. Spectral projections enjoy superior resolution provided the data is globally smooth, while the presence of jump discontinuities is responsible for spurious ${\cal O}(1)$ Gibbs oscillations in the neighborhood of edges and an overall deterioration to the unacceptab

Anne Gelb, Eitan Tadmor

We discuss a general framework for recovering edges in piecewise smooth functions with finitely many jump discontinuities, where $[f](x):=f(x+)-f(x-) \neq 0$. Our approach is based on two main aspects--localization using appropriate concentration kernels and separation of scales by nonlinear enhancement. To detect such edges, one employs concentration kernel

Hailiang Liu, Eitan Tadmor

We study the velocity gradients of the fundamental Eulerian equation, $\partial_t u +u\cdot \nabla u=F$, which shows up in different contexts dictated by the different modeling of $F$&#39;s. To this end we utilize a basic description for the spectral dynamics of $\nabla u$, expressed in terms of the (possibly complex) eigenvalues, $λ=λ(\nabla u)$, which are

Shlomo Engelberg, Hailiang Liu, Eitan Tadmor

We present a preliminary study of a new phenomena associated with the Euler-Poisson equations -- the so called critical threshold phenomena, where the answer to questions of global smoothness vs. finite time breakdown depends on whether the initial configuration crosses an intrinsic, ${O}(1)$ critical threshold. We investigate a class of Euler-Poisson equati

Eitan Tadmor

We introduce a new ladder of function spaces which is shown to fill in the gap between the weak $L^{p\infty}$ spaces and the larger Morrey spaces, $M^p$. Our motivation for introducing these new spaces, denoted $\V^{pq}$, is to gain a more accurate information on (compact) embeddings of Morrey spaces in appropriate Sobolev spaces. It is here that the seconda

Natalia Komarova, Igor Rivin

Motivated by a problem in learning theory, we are led to study the dominant eigenvalue of a class of random matrices. This turns out to be related to the roots of the derivative of random polynomials (generated by picking their roots uniformly at random in the interval [0, 1], although our results extend to other distributions). This, in turn, requires the s

Natalia Komarova, Igor Rivin

We study the convergence properties of a pair of learning algorithms (learning with and without memory). This leads us to study the dominant eigenvalue of a class of random matrices. This turns out to be related to the roots of the derivative of random polynomials (generated by picking their roots uniformly at random in the interval [0, 1], although our resu

Alexander Kirillov, Viktor Ostrik

The goal of this paper is to classify ``finite subgroups in U_q sl(2)&#39;&#39; where $q=e^{\piı/l}$ is a root of unity. We propose a definition of such a subgroup in terms of the category of representations of U_q sl(2); we show that this definition is a natural generalization of the notion of a subgroup in a reductive group, and that it is also related wit

Stanislaw D. Glazek

This contribution presents the running triple-gluon-vertex coupling constant, g_lambda, in Hamiltonians for the gluons that are characterized by the size 1/lambda. The coupling constant is obtained from renormalization group equations for effective particles in canonical light-front QCD in third order perturbation theory. lambda plays the role of a finite cu

M. Mangin-Brinet, J. Carbonell, V. A. Karmanov

The covariant light-front equations have been solved exactly for a two fermion system with different boson exchange ladder kernels. We present a method to study the cutoff dependence of these equations and to determine whether they need to be regularized or not. Results are presented for scalar and pseudo-scalar exchange. This latter furthermore exhibits som

F. T. Brandt, Ashok Das, J. Frenkel, J. C. Taylor

We discuss, using the imaginary time method, some aspects of the connection between the Ward identity, the non-analyticity of amplitudes and the causality relation in QED at finite temperature.

Ralph Blumenhagen, Boris Kors, Dieter Lust, Tassilo Ott

We review the construction and phenomenology of intersecting brane worlds. The breaking of chiral and supersymmetry together with a reduction of gauge symmetry by introducing D-branes at generic angles into type I or type II string compactifications is taken as a starting point for the engineering of phenomenologically appealing four-dimensional vacua. Examp

J. A. Gracey

We renormalize the Curci-Ferrari model at two loops in the MSbar scheme in an arbitrary covariant gauge.

Stefan Antusch

We propose a new approach for coupling the type II superstring to the Ramond-Ramond background of D-branes in the RNS formalism, alternative to introducing RR vertex operators. It is based on the mixing between Ramond-Ramond p-form excitations in the closed string spectrum and transversally polarized excitations in the open string spectrum.

G. W. Carter, D. M. Ostrovsky, E. V. Shuryak

We phenomenologically study whether partonic collisions responsible for the growth of hadron-hadron cross sections at high energy can be ascribed to instanton-induced processes. Although non-perturbative in nature, these interactions occur at the semi-hard scale $Q\sim 1-2$ GeV, and should therefore be described using information from deep inelastic leptonic

Cosmin Macesanu

We present a computation of QCD next-to-leading order corrections to the top production and decay process at linear colliders. The top quarks are allowed to be off-shell and the production and decay subprocesses are treated together, thus allowing for interference effects. Real gluon radiation effects as well as virtual corrections are evaluated. The framewo

D. G. Cerdeno, S. Khalil, C. Munoz

We study the direct detection of supersymmetric dark matter in the light of recent experimental results. In particular, we show that regions in the parameter space of several scenarios with a neutralino-nucleon cross section of the order of $10^{-6}$ pb, i.e., where current dark matter detectors are sensitive, can be obtained. These are supergravity scenario

L. B. Okun

Recollections about a few episodes from the history of physics of vacuum, connected with the names of Pomeranchuk, Landau, Zeldovich, Sakharov and Kirzhnits. The text of the talk will be published in the Proceedings of the International Conference ``From the Smallest to the Largest Distances&#39;&#39;, Tribute to Jean Tran-Thanh-Van, May 24-26, 2001 (``Surve

L. B. Okun

An extended text of the talk given at the conference ``2001: A Spacetime Odyssey&#39;&#39;, to be published in the Proceedings of the Inaugural Conference of the Michigan Center for Theoretical Physics, University of Michigan, Ann Arbor, 21-25 May 2001, M.J. Duff and J.T. Liu eds., World Scientific, Singapore, 2002; and of Historical Lecture ``Vacuum as seen

W. Beenakker, A. Werthenbach

We calculate the virtual electroweak Sudakov (double) logarithms at one- and two-loop level for arbitrary on-shell/on-resonance particles in the Standard Model. The associated Sudakov form factors apply in a universal way to arbitrary non-mass-suppressed electroweak processes at high energies, although this universality has to be interpreted with care. The a

Francesco Sannino

I briefly review the effective Lagrangians for three and two flavors QCD describing the relevant color superconductive light degrees of freedom and their electroweak interactions.

Deog Ki Hong

In this talk I discuss a recently proposed color superconducting phase of asymmetric quark matter where the up and down quark have different chemical potential, being in chemical equilibrium with electrons. Using Schwinger-Dyson equations derived from an effective theory of low-energy quasiparticles, a critical coupling for LOFF phase is estimated for both t

Johann Rafelski, Jean Letessier

We discuss properties of statistical QCD relevant in Fermi phase space model analysis of strange hadron production experimental data. We argue that the analysis results interpreted using established statistical QCD properties are demonstrating formation of the color deconfined state of matter in relativistic heavy ion collisions at highest CERN-SPS energies

Abdelhak Djouadi, Manuel Drees, Jean-Loic Kneur

We perform a complete analysis of the supersymmetric particle spectrum in the Minimal Supergravity (mSUGRA) model. We show that present constraints on the Higgs boson and superparticle masses from collider searches and precision measurements still allow for large regions of the mSUGRA parameter space where some sparticles as well as the heavier Higgs particl

S. Mohanty, U. A. Yajnik

The contributions made to the Working Group activities on neutrino and astroparticle physics are summarised in this article. The topics discussed were leptogenesis in Left-Right symmetric model, inflationary models in Raman-Sundrum scenarios, ultra high energy cosmic rays and neutrino oscillations in 4 flavour and decaying neutrino models.

Bernd A. Kniehl

The Higgs boson is the missing link of the Standard Model of elementary particle physics. We review its decay properties and production mechanisms at a future e^+ e^- linear collider and its e^- e^-, e^+- gamma, and gamma gamma modes, with special emphasis on the influence of quantum corrections. We also discuss how its quantum numbers and couplings can be e

Chuan-Hung Chen

We show that in the PQCD approach the $B\to ρ(ω) K$ decays display not only the dynamical penguin enhancement, the mechanism responsible for the large branching ratios (BRs) of $B\to ϕK$ decays, but also the importance of annihilation contributions. We find that the CP asymmetries (CPAs) of $B\to ρ^{\pm}K^{\mp}$, $B^{\mp}\to ρ^0(ω)K^{\mp}$ (class I) are all

Haruhiko Terao

First we give a review of the spurion formalism and the exact renormalization group equations for soft supersymmetry breaking parameters in general gauge theories. Next we discuss the minimal supersymmetric standard model coupled to superconformal theories leading to hierarchical Yukawa couplings by large anomalous dimensions of quarks and leptons. The soft

U. A. Yajnik

Developments in understanding of Baryogenesis are reviewed. We start with early motivations and the proposals in the context of GUTs. Next, the importance of the sphaleron solution and its implications are discussed. Studies of the Standard Model reveal that the latter has a Higgs structure incompatible with existence of observed \B asymmetry. We then discus

Yi Jin, Qubing Xie

In popular event generators of high energy reaction, the large Nc, the number of color approximation is implied, which reduces the possible interference effects, and the probability of color singlet chain reaches to about 100%. In $Nc=3$ real world, we show that not only the color interference decreases this probability to 83%, 77%, 72%, $...$, respectively

P. Belli, R. Bernabei, M. Amato, F. Cappella

DAMA is searching for rare processes by developing and using several kinds of radiopure scintillators: in particular, NaI(Tl), liquid Xenon and CaF$_2$(Eu). The main results are here summarized with particular attention to the investigation of the WIMP annual modulation signature.

Eugene T. Yamamoto

We present the first measurement of mid-rapidity $ϕ$ vector meson production in $Au+Au$ collisions at RHIC ($\sqrt{s_{_{NN}}} =130$ GeV) from the STAR detector. For the 11% most central collisions, the slope parameter from an exponential fit to the transverse mass distribution is $T=$~379$\pm$51(stat) $\pm$ 45(syst)~MeV, the yield $dN/dy$ $=5.73\pm$0.37(stat

Richard C. Brower

Strong coupling calculations for the glueball spectrum in an $AdS^7$ black hole are modified by introducing an UV cut-off at a Planck brane. A new normalizable state in the tensor spectrum is found which reproduces Einstein-Hilbert gravity up to exponentially small corrections due to off shell mixing with massive glueballs.

Peter Hasenfratz, Ferenc Niedermayer

We study the critical behaviour of the 2d dodecahedron spin model and investigate the conjecture that the discrete model describes the same continuum theory as the O(3) non-linear sigma model. In particular, we found that the anisotropy of the magnetization A(z) measured in a fixed physical volume decreases with increasing correlation length, at least up to

A. Di Giacomo

An updated review is presented of lattice investigations of colour confinement.

Monika Grothe

With 12.3 fb-1 collected by the BaBar experiment in 2001, the mixing parameter y = Delta(Gamma)/(2 Gamma) is determined from the ratio of the D0 lifetimes measured in the D0 --> K- pi+ and in the D0 --> K- K+ decay modes. The preliminary result y = (-1.0 +- 2.2(stat.) +- 1.7(syst.))% is obtained. Also presented is the status of measuring the mixing parameter

Klaus Moenig

As next generation e+e- linear collider the superconducting accelerator project TESLA has been proposed. In this note the physics potential goals of this project, which is highly complementary to LHC, are described.

Iain A. Stewart

We study a class of program schemes, NPSB, in which, aside from basic assignments, non-deterministic guessing and while loops, we have access to arrays; but where these arrays are binary write-once in that they are initialized to `zero&#39; and can only ever be set to `one&#39;. We show, amongst other results, that: NPSB can be realized as a vectorized Linds

S. V. Dordevic, E. J. Singley, D. N. Basov, Seiki Komiya

We report on generic trends in the behavior of the interlayer penetration depth $λ_c$ of several different classes of quasi two-dimensional superconductors including high-T$_c$ cuprates, Sr$_2$RuO$_4$, transition metal dichalcogenides and organic materials of the $(BEDT-TTF)_2X$ - series. Analysis of these trends reveals two distinct patterns in the scaling

Christopher L. Rogers, Andrew M. Rappe

We present a derivation of the stress field for an interacting quantum system within the framework of local density functional theory. The formulation is geometric in nature and exploits the relationship between the strain tensor field and Riemannian metric tensor field. Within this formulation, we demonstrate that the stress field is unique up to a single a

Nicholas Choly, Efthimios Kaxiras

Kinetic energy functionals of the electronic density are used to model large systems in the context of density functional theory, without the need to obtain electronic wavefunctions. We discuss the problems associated with the application of widely used kinetic energy functionals to non-periodic systems. We develop a method that circumvents this difficulty a

W. E. Bies, H. Ehrenreich, E. Runge

The techniques used previously to calculate the three-fold thermal conductivity reduction due to phonon dispersion in GaAs/AlAs superlattices (SLs) are applied to HgTe/CdTe SLs. The reduction factor is approximately the same, indicating that this SL may be applicable both as a photodetector and a thermoelectric cooler.

Pablo Pou, Fernando Flores, Jose Ortega, Ruben Perez

Electron correlation effects in Fe are analyzed using a first principles LCAO-scheme. In our approach, we first use a local orbital DFT-LDA solution to introduce a Hubbard Hamiltonian without fitting parameters. In a second step, we introduce a many-body solution to this Hamiltonian using a DMF approximation. Our analysis shows that magnetism in Fe is an eff

B. J. Schulz, K. Binder, M. Mueller

We present a method for estimating the density of states of a classical statistical model. The algorithm successfully combines the Wang-Landau flat histogram method with the N-fold way in order to improve efficiency of the original single spin flip version. We test our implementation of the Wang-Landau method with the two-dimensional nearest neighbor Ising m

Wolfhard Janke, Bernd A. Berg, Alain Billoire

We present results of recent high-statistics Monte Carlo simulations of the Edwards-Anderson Ising spin-glass model in three and four dimensions. The study is based on a non-Boltzmann sampling technique, the multi-overlap algorithm which is specifically tailored for sampling rare-event states. We thus concentrate on those properties which are difficult to ob

Josep Perello, Jaume Masoliver

Option pricing is mainly based on ideal market conditions which are well represented by the Geometric Brownian Motion (GBM) as market model. We study the effect of non-ideal market conditions on the price of the option. We focus our attention on two crucial aspects appearing in real markets: The influence of heavy tails and the effect of colored noise. We wi

M. Dimian, H. Kachkachi

We study the influence of surface anisotropy on the zero-temperature hysteretic properties of a small single-domain magnetic particle, and give an estimation of the anisotropy constant for which deviations from the Stoner-Wohlfarth model are observed. We consider a spherical particle with simple cubic crystalline structure, a uniaxial anisotropy for core spi

L. Pietronero, M. Bottaccio, R. Mohayaee, M. Montuori

The evolution and the statistical properties of an infinite gravitating system represent an interesting and widely investigated subject of research. In cosmology, the standard approach is based on equations of hydrodynamics. In the present paper, we analyze the problem from a different perspective, which is usually neglected. We focus our attention on the fa

N. Hasselmann, A. H. Castro Neto, C. Morais Smith

We calculate the influence of transverse fluctuations on the longitudinal dynamics in the striped phase of cuprates by using the bosonization technique. We find that a charge density wave instability can arise if the stripe is quarter filled and the underlying lattice potential has a zigzag symmetry. Our results explain why static stripes are experimentally

J. C. Phillips

With the discovery of Tc s over 100K, continuously biased hole-doped semiconductive C60+y has joined the family of high-temperature superconductors (HTSC) previously dominated by the ceramic cuprates. The phase diagrams of these two quite different materials are remarkably similar, despite the absence from undoped C60+y of magnetic order. This supports perco

B. J. Baelus, S. V. Yampolskii, F. M. Peeters

Using the nonlinear Ginzburg-Landau theory we investigated the dependence of the magnetic coupling between two concentric mesoscopic superconducting rings on their thickness. The size of this magnetic coupling increases with the thickness of the rings.

Jose A Cuesta, Angel Sanchez

We rigorously prove that a wide class of one-dimensional growth models with onsite periodic potential, such as the discrete sine-Gordon model, have no phase transition at any temperature $T>0$. The proof relies on the spectral analysis of the transfer operator associated to the models. We show that this operator is Hilbert-Schmidt and that its maximum eigenv

A. C. D. van Enter, H. G. Schaap

We study a Gaussian Potts-Hopfield model. Whereas for Ising spins and two disorder variables per site the chaotic pair scenario is realized, we find that for q-state Potts spins [{q(q-1} \over 2]-tuples occur. Beyond the breaking of a continous stochastic symmetry, we study the fluctuations and obtain the Newman-Stein metastate description for our model.

F. S. Bergeret, A. F. Volkov, K. B. Efetov

We study the dependence of the local density of states (LDOS) on coordinates for a superconductor-ferromagnet (S/F) bilayer and a S/F/S structure assuming that the exchange energy h in the ferromagnet is sufficiently large: $% hτ>>1,$ where $τ$ is the elastic relaxation time. This limit cannot be described by the Usadel equation and we solve the more general

Piotr Magierski, Aurel Bulgac

We discuss properties of the Fermi system which contain one or more spherical (or almost spherical) objects. The interplay between various effects, such as shell correction and chaotic behavior is considered. We briefly mention the role of the temperature, pairing, and effects associated with bubble dynamics.

A. P. Ramirez, B. S. Shastry, A. Hayashi, J. J. Krajewski

Field-driven phase transitions generally arise from competition between Zeeman energy and exchange or crystal-field anisotropy. Here we present the phase diagram of a frustrated pyrochlore magnet Gd2Ti2O7, where crystal field splitting is small compared to the dipolar energy. We find good agreement between zero-temperature critical fields and those obtained

Branislav K. Nikolic

The study explores perpendicular transport through macroscopically inhomogeneous three-dimensional disordered conductors using mesoscopic methods (real-space Green function technique in a two-probe measuring geometry). The nanoscale samples (containing $\sim1000$ atoms) are modeled by a tight-binding Hamiltonian on a simple cubic lattice where disorder is in