May 2003 arXiv papers — page 17

J. C. Berengut, V. A. Dzuba, V. V. Flambaum

This work presents a method for the ab initio calculation of isotope shift in atoms and ions with one valence electron above closed shells. As a zero approximation we use relativistic Hartree-Fock and then calculate correlation corrections. The main motivation for developing the method comes from the need to analyse whether different isotope abundances in ea

D. Sornette, A. Helmstetter, J. V. Andersen, S. Gluzman

In a previous work [Helmstetter, 2003], we have proposed a simple physical model to explain the accelerating displacements preceding some catastrophic landslides, based on a slider-block model with a state and velocity dependent friction law. This model predicts two regimes of sliding, stable and unstable leading to a critical finite-time singularity. This m

Hugo Touchette, Seth Lloyd

We propose an information-theoretic framework for analyzing control systems based on the close relationship of controllers to communication channels. A communication channel takes an input state and transforms it into an output state. A controller, similarly, takes the initial state of a system to be controlled and transforms it into a target state. In this

A. Majumder, V. Koch

We address the issue of the degree of equilibrium achieved in a high energy heavy-ion collision. Specifically, we explore the consequences of incomplete strangeness chemical equilibrium. This is achieved over a volume V of the order of the strangeness correlation length and is assumed to be smaller than the freeze-out volume. Probability distributions of str

Hiroyuki Sako

Measurements of HBT correlations and event-by-event fluctuations of mean pT and the net charge in Pb-Au collisions at 40, 80, and 158 AGeV/c are presented. From comparisons of HBT radii measured from AGS to RHIC energies, a universal mean free path of pions at the thermal freeze-out of about 1 fm is derived. Non-statistical mean pT fluctuations of about 0.7

E. S. Mchedlova, L. V. Krasichkov

The electronic model of Van der Pol oscillator with piecewise linear V-I--characteristics of nonlinear element is proposed. It is carried out the experimental investigations of behaviour of the Van der Pol oscillator under external periodic force. The parameter plane "the amplitude of external force -- the frequency of external force" for the dynamic

Nero Budur

We give a Hodge-theoretic interpretation of the multiplier ideal of an effective divisor on a smooth complex variety. More precisely, we show that the associated graded coherent sheaf with respect to the jumping-number filtration can be recovered from the smallest piece of M. Saito's Hodge filtration of the D-module of vanishing cycles.

Lei Ni

In this paper, we prove a general maximum principle for the time dependent Lichnerowicz heat equation on symmetric tensors coupled with the Ricci flow on complete Riemannian manifolds. As an application we construct complete manifolds with bounded nonnegative sectional curvature of dimension greater than or equal to four such that the Ricci flow does not pre

Matthieu Romagny

We give the basic definitions of group actions on (algebraic) stacks, and prove the existence of fixed points and quotients as (algebraic) stacks.

Sergey Yuzvinsky

In the paper, we study special configurations of lines and points in the complex projective plane, so called k-nets. We describe the role of these configurations in studies of cohomology on arrangement complements. Our most general result is the restriction on k - it can be only 3,4, or 5. The most interesting class of nets is formed by 3-nets that relate to

Stephen Doty, Karin Erdmann, Anne Henke

We initiate the systematic study of endomorphism algebras of permutation modules and show they are obtainable by a descent from a certain "generic" Hecke algebra, infinite-dimensional in general, coming from the universal enveloping algebra of gl_n (or sl_n). The endomorphism algebras and the generic algebras are cellular. We give several equivalent

Franc Forstneric, Jasna Prezelj

We give a proof of the following theorem of M. Gromov (Oka's principle for holomorphic sections of elliptic bundles, J. Amer. Math. Soc., 2 (1989), 851-897). Let Z be a holomorphic fiber bundle over a Stein manifold. If the fiber of Z admits a dominating holomorphic spray then the inclusion of the space of global holomorphic sections of Z into the space

Franc Forstneric, Jernej Kozak

We give an explicit construction of special strongly pseudoconvex domains in C^n of handlebody type, i.e., domains which are small tubes surrounding the union of a quadratic strongly pseudoconvex domain with an attached totally real handle. Among other results, we give another proof of Lemma 3.4.3. from the paper of Y. Eliashberg, "Topological characteri

Christophe Mourougane

We compute the Bott-Chern classes of the metric Euler sequence describing the relative tangent bundle of the variety P(E) of hyperplans of a holomorphic hermitian vector bundle (E,h) on a complex manifold. We give applications to the construction of the arithmetic characteristic classes of an arithmetic vector bundle and to the computation of the height of P

Dirk Segers, Willem Veys

We study the local topological zeta function associated to a complex function that is holomorphic at the origin of C^2 (respectively C^3). We determine all possible poles less than -1/2 (respectively -1). On C^2 our result is a generalization of the fact that the log canonical threshold is never in ]5/6,1[. Similar statements are true for the motivic zeta fu

Chris A. J. Klaassen, Philip J. Mokveld, Bert van Es

Consider estimation of the regression parameter in the accelerated failure time model, when data are obtained by cross sectional sampling. It is shown that it is possible under regularity of the model to construct an efficient estimator of the unknown Euclidean regression parameter if the distribution of the covariate vector is known and also if it is unknow

Sever Silvestru Dragomir

An inequality providing some bounds for the integral mean via Pompeiu's mean value theorem and applications for quadrature rules and special means are given.

Sever Silvestru Dragomir

Some Ostrowski type inequalities via Cauchy's mean value theorem and applications for certain particular instances of functions are given.

Sever Silvestru Dragomir

A counterpart of the famous Bessel's inequality for orthornormal families in real or complex inner product spaces is given. Applications for some Gruss type inequalities are also provided.

Boris Y. Rubinstein, Leonid G. Fel

Explicit expressions for restricted partition function $W(s,{\bf d}^m)$ and its quasiperiodic components $W_j(s,{\bf d}^m)$ (called {\em Sylvester waves}) for a set of positive integers ${\bf d}^m = \{d_1, d_2, ..., d_m\}$ are derived. The formulas are represented in a form of a finite sum over Bernoulli and Euler polynomials of higher order with periodic co

Meng Chen

We study the canonical stability of a smooth projective 3-fold $V$ of general type. We prove that (1) $|5K_V|$ gives a birational map onto its image provided the geometric genus $p_g\geq 4$; (2) $|6K_V|$ gives a birational map provided $p_g=3$. Known examples show that both are optimal. This fact can be viewed as parallel to surface case, though people know

Nero Budur

We describe a relation between two invariants that measure the complexity of a hypersurface singularity. One is the Hodge spectrum which is related to the monodromy and the Hodge filtration on the cohomology of the Milnor fiber. The other is the multiplier ideal, having to do with log resolutions.

Franc Forstneric

The paper is related to the author's talk at the Hayama Symposium in Complex Analysis in December 2000. In section 1 we survey results on the Oka principle for sections of holomorphic submersions over Stein manifolds. In section 2 we apply these results to the lifting problem for holomorphic mappings from Stein manifolds, and in section 3 we apply them t

Miran Cerne, Franc Forstneric

We study the existence of proper holomorphic embeddings of bordered Riemann surfaces into the complex plane C^2. Denote by M(R) the moduli space consisting of all equivalence classes of complex structures J on a given smooth oriented bordered surface R. We introduce a class F(R) in M(R)with the following properties: (1) F(R) is nonempty and open (in a natura

Florin Constantinescu

We present supersymmetric positive definite scalar products together with natural Krein structures of supersymmetries.

J. Spinelly, E. R. Bezerra de Mello

In this paper we analyse the vacuum polarization effects due to a magnetic flux on massless fermionic fields in a cosmic string background. Three distinct configurations of magnetic fields are considered. In all of them the magnetic fluxes are confined in a long cylindrical tube of finite radius.

D. C. Rodrigues, C. Wotzasek

We have found a (classical) competition between duality and gauge symmetries when trying to obtain an explicit dual to the non-nonabelian version of the self-dual model proposed by Townsend, Pilch and van Nieuwenhuizen\cite{TPvN} (NASD) either through gauge embedding procedures or gauge invariant master approach. We found that the theory dual to NASD {\it is

R. Manvelyan, W. Ruehl

The multiplet of superconformal anomalous currents in the case $(1,0)$, $d=6$ is derived. The supersymmetric multiplet of anomalies contains the trace of the energy momentum tensor, the gamma trace of the supercurrent and some topological vector current with divergence equal to the $R$-current anomaly. The extension of this consideration to the $(2,0)$ case

Amit Giveon, Eliezer Rabinovici, Amit Sever

We review the construction of time-dependent backgrounds with space-like singularities. We mainly consider exact CFT backgrounds. The algebraic and geometric aspects of these backgrounds are discussed. Physical issues, results and difficulties associated with such systems are reviewed. Finally, we present some new results: a two dimensional cosmology in the

L. Bonora, C. Maccaferri, D. Mamone, M. Salizzoni

This review of bosonic string field theory is concentrated on two main subjects. In the first part we revisit the construction of the three string vertex and rederive the relevant Neumann coefficients both for the matter and the ghost part following a conformal field theory approach. We use this formulation to solve the VSFT equation of motion for the ghost

Diuliu-Emanuel Diaconescu, Gregory Moore, Edward Witten

We show how some aspects of the K-theory classification of RR fluxes follow from a careful analysis of the phase of the M-theory action. This is a shortened and simplified companion paper to ``E8 Gauge Theory, and a Derivation of K-Theory from M-Theory.''

B. C. Tiburzi, W. Detmold, G. A. Miller

We calculate parton and generalized parton distributions in Minkowski space using a scalar propagator with a pair of complex conjugate poles. Correct spectral and support properties are obtained only after careful analytic continuation from Euclidean space. Alternately the quark distribution function can be calculated from modified cutting rules, which put t

Peter Petreczky

I review recent progress in relating meson spectral function to imaginary time correlation function at finite temperature calculated on isotropic as well as on anisotropic lattices. Special attention is payed for the lattice artifacts present in calculation of meson spectral functions. Results in the case of light quarks as well as heavy quarks are reviewed

V. Elias

Using renormalization-group methods, differential equations can be obtained for the all-orders summation of leading and subsequent non-leading logarithmic corrections to QCD perturbative series for a number of processes and correlation functions. For a QCD perturbative series known to four orders, such as the e+ e- annihilation cross-section, explicit soluti

R. J. M. Covolan, M. S. Soares

A phenomenological description of diffractive dijet hadroproduction via double Pomeron exchange is presented. This description is based on a modified version of the Ingelman-Schlein model which includes the evolution of the Pomeron structure function and corrections regarding rapidity gap suppression effects. The same quark-dominant Pomeron structure functio

D. Autiero, G. De Lellis, A. Donini, M. Komatsu

We deepen the study of the so-called ``silver channel'' $ν_e \to ν_τ$ \cite{Donini:2002rm} and of its relevance to solve some of the ambiguities that can arise in the simultaneous measurement of $(θ_{13},δ)$ at the Neutrino Factory by presenting in full detail the characteristics of the considered OPERA-like detector and the experimental treatment of

Michael I. Eides, Valery A. Shelyuto

We calculate radiative corrections to the Lamb shift of order $α^3(Zα)^5m$ and radiative corrections to hyperfine splitting of order $α^3(Zα)E_F$ generated by the diagrams with insertions of radiative photons and electron polarization loops in the graphs with two external photons. We also obtain the radiative-recoil correction to hyperfine splitting in muoni

Lianyi He, Guang Bian, Jinfeng Liao, Pengfei Zhuang

Quark deconfinement phase transition at finite temperature and density is investigated in the frame of quantum mechanics. By solving the Schrödinger equation for a heavy quark in a thermal mean field, we calculate the quark probability distribution as a function of temperature and density. The confined wave function in the vacuum expands outward rapidly when

Tim Oliver Eynck, Eric Laenen, Lorenzo Magnea

It has been observed that in the DIS scheme the refactorization of the Drell-Yan cross section leading to exponentiation of threshold logarithms can also be used to organize a class of constant terms, most of which arise from the ratio of the timelike Sudakov form factor to its spacelike counterpart. We extend this exponentiation to include all constant term

R. Peschanski

Diffractive production of the Higgs boson at hadron colliders is discussed in the light of the observed rate of hard diffractive dijet events at the Tevatron. The Higgs predictions of models successful for dijets are compared. LHC seems promising for a diffractive light Higgs boson and its mass determination. Hard diffractive dijets, diphotons and dileptons

Jun Nishimura

We propose a new method for simulating QCD at finite density. The method is based on a general factorization property of distribution functions of observables, and it is therefore applicable to any system with a complex action. The so-called overlap problem is completely eliminated by the use of constrained simulations. We test this method in a Random Matrix

P. Chumney, S. Dasu, J. Lackey, M. Jaworski

The Compact Muon Solenoid (CMS) calorimeter regional trigger system is designed to detect signatures of isolated and non-isolated electrons/photons, jets, ?-leptons, and missing and total transverse energy using a deadtimeless pipelined architecture. This system contains 18 crates of custom-built electronics. The pre-production prototype backplane, boards, l

Doris Yangsoo Kim

The E831/FOCUS experiment at Fermilab is a photoproduction experiment which generated high quality charm particles. During its run, we obtained a large data set, including more than 1 million charm mesons in the Kpi/K2pi/K3pi mode decays. The current analysis efforts by the collaboration members are quite active and diverse. I will summarize the recent paper

Thomas E. Coan

Recent CLEO results on the observation of the $Υ(1D)$ state and a search for the $η_b(1S)$ state from a data sample of $4.7 \times 10^6\,Υ(3S)$ decays collected with the CLEO-III detector, and a measurement of the $η^{\prime}$ production spectrum using $1.9 \times 10^6\,Υ(1S)$ decays collected with the CLEO-II detector are described.

F. E. Gray

The muon (g-2) experiment at Brookhaven National Laboratory has measured the anomalous magnetic moment of the positive muon with a precision of 0.7 ppm. This paper presents that result, concentrating on some of the important experimental issues that arise in extracting the anomalous precession frequency from the data.

T. Tomura

Recent measurements of branching fractions and CP-violating partial-rate asymmetries for rare hadronic B-meson decays by the asymmetric-energy B-factory experiments, Belle and BaBar, are reviewed.

Subenoy Chakraborty, N. C. Chakraborty, Ujjal Debnath

It is shown that minimally coupled scalar field in Brans-Dicke theory with varying speed of light can solve the quintessence problem and it is possible to have a non-decelerated expansion of the present universe with BD-theory for anisotropic models without any matter.

Subenoy Chakraborty, N. C. Chakraborty, Ujjal Debnath

In this paper, we have studied Brans-Dicke Cosmology in anisotropic Kantowski-Sachs space-time model; considering variation of the velocity of light. We have addressed the flatness problem considering both the cases namely, (i) when the Brans-Dicke scale field $ϕ$ is constant (ii) when $ϕ$ varies, specially for radiation dominated era perturbatively and non-

Jeeva Anandan, Naresh Dadhich, Parampreet Singh

We present, for the first time, an action principle that gives the equations of motion of an extended body possessing multipole moments in an external gravitational field, in the weak field limit. From the action, the experimentally observable quantum phase shifts in the wavefunction of an extended object due to the coupling of its multipole moments with the

John Miritzis

We study the late time evolution of positively curved FRW models with a scalar field which arises in the conformal frame of the $R+αR^{2}$ theory. The resulted three-dimensional dynamical system has two equilibrium solutions corresponding to a de Sitter space and an ever expanding closed universe. We analyze the structure of the first equilibrium with the me

Carlos Barcelo, Stefano Liberati, Matt Visser

It is by now well known that various condensed matter systems may be used to mimic many of the kinematic aspects of general relativity, and in particular of curved-spacetime quantum field theory. In this essay we will take a look at what would be needed to mimic a cosmological spacetime -- to be precise a spatially flat FRW cosmology -- in one of these analo

Etera R. Livine, Alejandro Perez, Carlo Rovelli

A number of background independent quantizations procedures have recently been employed in 4d nonperturbative quantum gravity. We investigate and illustrate these techniques and their relation in the context of a simple 2d topological theory. We discuss canonical quantization, loop or spin network states, path integral quantization over a discretization of t

Ulla Bergsten, Johan Schubert, Per Svensson

Within the scope of the three-year ANTI-SUBMARINE WARFARE project of the National Defence Research Establishment, the INFORMATION SYSTEMS subproject has developed the demonstration prototype Dezzy for handling and analysis of intelligence reports concerning foreign underwater activities. ----- Inom ramen för FOA:s treåriga huvudprojekt UBÅTSSKYDD har delproj

Johan Schubert

In this paper we develop a method for report level tracking based on Dempster-Shafer clustering using Potts spin neural networks where clusters of incoming reports are gradually fused into existing tracks, one cluster for each track. Incoming reports are put into a cluster and continuous reclustering of older reports is made in order to obtain maximum associ

Johan Schubert

In this paper we develop a method for clustering belief functions based on attracting and conflicting metalevel evidence. Such clustering is done when the belief functions concern multiple events, and all belief functions are mixed up. The clustering process is used as the means for separating the belief functions into subsets that should be handled independ

Johan Schubert

In this paper we develop methods for selection of templates and use these templates to recluster an already performed Dempster-Shafer clustering taking into account intelligence to template fit during the reclustering phase. By this process the risk of erroneous force aggregation based on some misplace pieces of evidence from the first clustering process is

John Cantwell, Johan Schubert, Johan Walter

In this paper we present an application where we put together two methods for clustering and classification into a force aggregation method. Both methods are based on conflicts between elements. These methods work with different type of elements (intelligence reports, vehicles, military units) on different hierarchical levels using specific conflict assessme

Mats Bengtsson, Johan Schubert

In this article we investigate a problem within Dempster-Shafer theory where 2**q - 1 pieces of evidence are clustered into q clusters by minimizing a metaconflict function, or equivalently, by minimizing the sum of weight of conflict over all clusters. Previously one of us developed a method based on a Hopfield and Tank model. However, for very large proble

Johan Schubert

In this paper we demonstrate that it is possible to manage intelligence in constant time as a pre-process to information fusion through a series of processes dealing with issues such as clustering reports, ranking reports with respect to importance, extraction of prototypes from clusters and immediate classification of newly arriving intelligence reports. Th

Johan Schubert

In this article we study a problem within Dempster-Shafer theory where 2**n - 1 pieces of evidence are clustered by a neural structure into n clusters. The clustering is done by minimizing a metaconflict function. Previously we developed a method based on iterative optimization. However, for large scale problems we need a method with lower computational comp

Johan Schubert

In this paper we extend an earlier result within Dempster-Shafer theory ["Fast Dempster-Shafer Clustering Using a Neural Network Structure," in Proc. Seventh Int. Conf. Information Processing and Management of Uncertainty in Knowledge-Based Systems (IPMU'98)] where several pieces of evidence were clustered into a fixed number of clusters using a

Johan Schubert

In this paper we extend an earlier result within Dempster-Shafer theory ["Fast Dempster-Shafer Clustering Using a Neural Network Structure," in Proc. Seventh Int. Conf. Information Processing and Management of Uncertainty in Knowledge-Based Systems (IPMU 98)] where a large number of pieces of evidence are clustered into subsets by a neural network st

Johan Schubert

In this paper we study a problem within Dempster-Shafer theory where 2**n - 1 pieces of evidence are clustered by a neural structure into n clusters. The clustering is done by minimizing a metaconflict function. Previously we developed a method based on iterative optimization. However, for large scale problems we need a method with lower computational comple

Ulla Bergsten, Johan Schubert, Per Svensson

We describe how specialized database technology and data analysis methods were applied by the Swedish defense to help deal with the violation of Swedish marine territory by foreign submarine intruders during the Eighties and early Nineties. Among several approaches tried some yielded interesting information, although most of the key questions remain unanswer

Johan Schubert

We develop a classification method for incoming pieces of evidence in Dempster-Shafer theory. This methodology is based on previous work with clustering and specification of originally nonspecific evidence. This methodology is here put in order for fast classification of future incoming pieces of evidence by comparing them with prototypes representing the cl

Johan Schubert

In an earlier article [J. Schubert, On nonspecific evidence, Int. J. Intell. Syst. 8(6), 711-725 (1993)] we established within Dempster-Shafer theory a criterion function called the metaconflict function. With this criterion we can partition into subsets a set of several pieces of evidence with propositions that are weakly specified in the sense that it may

Johan Schubert

Thomas M. Strat has developed a decision-theoretic apparatus for Dempster-Shafer theory (Decision analysis using belief functions, Intern. J. Approx. Reason. 4(5/6), 391-417, 1990). In this apparatus, expected utility intervals are constructed for different choices. The choice with the highest expected utility is preferable to others. However, to find the pr

Johan Schubert

In Intelligence Analysis it is of vital importance to manage uncertainty. Intelligence data is almost always uncertain and incomplete, making it necessary to reason and taking decisions under uncertainty. One way to manage the uncertainty in Intelligence Analysis is Dempster-Shafer Theory. This thesis contains five results regarding multiple target tracks an

Johan Schubert

When reasoning with uncertainty there are many situations where evidences are not only uncertain but their propositions may also be weakly specified in the sense that it may not be certain to which event a proposition is referring. It is then crucial not to combine such evidences in the mistaken belief that they are referring to the same event. This situatio

Johan Schubert

This article is an extension of the results of two earlier articles. In [J. Schubert, On nonspecific evidence, Int. J. Intell. Syst. 8 (1993) 711-725] we established within Dempster-Shafer theory a criterion function called the metaconflict function. With this criterion we can partition into subsets a set of several pieces of evidence with propositions that

Ulla Bergsten, Johan Schubert

For the case of evidence ordered in a complete directed acyclic graph this paper presents a new algorithm with lower computational complexity for Dempster's rule than that of step-by-step application of Dempster's rule. In this problem, every original pair of evidences, has a corresponding evidence against the simultaneous belief in both propositions

Johan Schubert

When simultaneously reasoning with evidences about several different events it is necessary to separate the evidence according to event. These events should then be handled independently. However, when propositions of evidences are weakly specified in the sense that it may not be certain to which event they are referring, this may not be directly possible. I

Rhonald Lua, Alexander L. Borovinskiy, Alexander Yu. Grosberg

We propose a novel combinatorial algorithm for efficient generation of Hamiltonian walks and cycles on a cubic lattice, modeling the conformations of lattice toy proteins. Through extensive tests on small lattices (allowing complete enumeration of Hamiltonian paths), we establish that the new algorithm, although not perfect, is a significant improvement over

Sangwook Wu, Joerg Schmalian, Gabriel Kotliar, Peter G Wolynes

We present a self-consistent local approach to self generated glassiness which is based on the concept of the dynamical mean field theory to many body systems. Using a replica approach to self generated glassiness, we map the problem onto an effective local problem which can be solved exactly. Applying the approach to the Brazovskii-model, relevant to a larg

WL Vandoolaeghe

In this thesis the formation and properties of a polymer gel on and at a surface are investigated. The gel under investigation is defined as a three-dimensional network of "phantom" macromolecules that form permanent links with one another and also with confining planar surfaces. The precise location of the crosslinks on the wall or on another macrom

V. Y. Butko, X. Chi, D. V. Lang, A. P. Ramirez

We report on fabrication and characterization of field effect transistors (FETs) on single-crystal pentacene. These FETs exhibit hole conductivity with room temperature effective mobility up to 0.30 cm2/Vs and on/off ratios up to 5*10^6. A negative gate voltage of -50V significantly decreases the activation energy (Ea) down to 0.143 eV near room temperature.

A. Rebei, M. Simionato, G. J. Parker

We calculate the correlation functions of uniform magnetization in thin ferromagnetic films for small deviations from equilibrium, by using a functional formalism. To take account of dissipation and fluctuations consistently, the magnetization is coupled to a bosonic heat bath. The correlation functions show strong dependence on the nature of the coupling be

P. M. Shirage, D. D. Shivagan, L. A. Ekal, N. V. Desai

Junction between metal, superconductor and semiconductor materials seems to be promising for their applications as the electronic devices, microelectronic devices and high power transmission. E-mail shpawar_phy@unishivaji.ac.in.

O. Z. Karimov, G. H. John, R. T. Harley, W. H. Lau

Time-resolved optical measurements in (110)-oriented GaAs/AlGaAs quantum wells show a ten-fold increase of the spin-relaxation rate as a function of applied electric field from 20 to 80 kV cm-1 at 170 K and indicate a similar variation at 300 K, in agreement with calculations based on the Rashba effect. Spin relaxation is almost field-independent below 20 kV

P M Shirage, D D Shivagan, S H Pawar

Metal/superconductor/semiconductor (Ag/TlBaCaCuO/CdSe) heterostructures have been successfully fabricated using pulse-electrodeposition technique. The electrochemical parameters are optimized and diffusion free growth of CdSe onto Ag/TlBaCaCuO was obtained by employing under-potential deposition and by studying nucleation and growth mechanism during depositi

Helmut G. Katzgraber

Results from Monte Carlo simulations of the two-dimensional gauge glass supporting a zero-temperature transition are presented. A finite-size scaling analysis of the correlation length shows that the system does not exhibit spin-glass order at finite temperatures. These results are compared to earlier claims of a finite-temperature transition.

H. Gonzalez-Jorge, D. Gonzalez-Salgado, J. Peleteiro, E. Carballo

A procedure for avoiding the quenching associated to a previously reported method for inducing currents in superconducting rings [H. Gonzalez-Jorge et al., Appl. Phys. Lett. 81, 4207 (2002)] is proposed. High persistent currents are induced in two textured YBCO rings (1536 and 2870 A) using a modified version of the original procedure that consist on a strai

Jerome Leon, Frederic Geniet

A nonlinear system possessing a natural forbidden band gap can transmit energy of a signal with a frequency in the gap, as recently shown for the nonlinear chain of coupled pendula [Phys Rev Lett 89 (2002) 134102]. This process of nonlinear supratransmission, occurring at a threshold exactly predictable in many cases, is shown to have a simple experimental r

Virgile Viasnoff, Francois Lequeux

In this paper we analyze the changes in the microscopic dynamics of a colloidal glass submitted to an oscillatory shear. We use Multispeckle diffusing Wave Spectroscopy to monitor the transient dynamical regimes following a shear application. We show that the system displays a spontaneous aging that is amplified by a low amplitude oscillation (overaging) but

Satya N. Majumdar, Alan J. Bray

We calculate the survival probability P_S(t) up to time t of a tracer particle moving along a deterministic trajectory in a continuous d-dimensional space in the presence of diffusing but mutually noninteracting traps. In particular, for a tracer particle moving ballistically with a constant velocity c, we obtain an exact expression for P_S(t), valid for all

Ki-Seok Kim, Jae-Hyeon Eom, Young-Il Seo, Sung-Ho Suck Salk

We examine the roles of massless Dirac spinon and spin singlet pair excitations on the phase transition in $d-wave$ superconductors. Although the massless spinon excitations in the presence of the spin singlet pair excitations do not alter the nature of the phase transition at $T = 0$, that is, the XY universality class, they are seen to induce an additional

O. Pilla, A. Fontana, J. R. Goncalves, G. Viliani

The study of the effects of the density variations on the vibrational dynamics in vitreous silica is presented. A detailed analysis of the dynamical structure factor, as well as of the current spectra, allows the identification of a flattened transverse branch which is highly sensitive to the density variations. The experimental variations on the intensity a

T. Ochiai, K. Ohtaka

A fully relativistic description of the electron energy loss and the induced radiation emission in arbitrary arrays of non-overlapping metallic cylinders is presented in terms of the multiple scattering method on the basis of vector cylindrical waves. Numerical analysis is given for dilute and dense arrays of Aluminum cylinders with a nanoscale diameter. The

B. Arnaud, S. Lebègue, M. Alouani

The quasiparticle decays due to electron-electron interaction in silicon are studied by means of first-principles all-electron GW approximation. The spectral function as well as the dominant relaxation mechanisms giving rise to the finite life time of quasiparticles are analyzed. It is then shown that these life times and quasiparticle energies can be used t

Keshav N. Shrivastava

We have considered the response at two energies corresponding to two plateaus in the quantum Hall effect. Since the thermoelectric power involves the derivative of conductivity with respect to energy, we introduce the concept of a line width and hence an activation energy. We then use the Hall conductivity to define the thermoelectric power at the centre of

P. S. Clegg, R. J. Birgeneau, S. Park, C. W. Garland

The effects of dispersed aerosil nanoparticles on two of the phase transitions of the thermotropic liquid crystal material 4-n-pentylphenylthiol-4'-n-octyloxybenzoate 8barS5 have been studied using high-resolution x-ray diffraction techniques. The aerosils hydrogen bond together to form a gel which imposes a weak quenched disorder on the liquid crystal.

T Dutta, N I Lebovka, S Tarafdar

We study condensation and evaporation of particles which repel each other, using a simple set of rules on a square lattice. Different results are obtained for a mobile and an immobile surface layer.A two point limit cycle is observed for high temperature and low pressure in both cases. Here the coverage oscillates between a high and a low value without ever

Lev B. Zuev

The deBroglie relation is applied to the analysis of auto-wave processes of localized plastic flow in various materials and the results obtained are considered. It is found that the localization of plastic deformation can be conveniently addressed by invoking a hypothetical quasi-particle conjugated with the wave process of flow localization. The mass of the

S. A. Bonev, F. Gygi, T. Ogitsu, G. Galli

We present a theoretical study of solid carbon dioxide up to 50GPa and 1500K using first-principles calculations. In this pressure-temperature range, interpretations of recent experiments have suggested the existence of CO2 phases which are intermediate between molecular and covalent-bonded solids. We reexamine the concept of intermediate phases in the CO2 p

A. Daerr, P. Lee, J. Lanuza, E. Clement

We report here on a laboratory-scale experiment which reproduces a rich variety of natural patterns with few control parameters. In particular, we focus on intriguing rhomboid structures often found on sandy shores and flats. We show that the standard views based on water surface waves come short to explain the phenomenon and we evidence a new mechanism base

Jason X. Prochaska, Eric Gawiser, Arthur M. Wolfe, Sandro Castro

We present accurate metallicity measurements for 121 damped Lya systems at 0.5<z<5 including ~50 new measurements from our recently published Echellette Spectrograph and Imager surveys. This dataset is analysed to determine the age-metallicity relation of neutral gas in the universe. Contrary to previous datasets this sample shows statistically significant e

Jason X. Prochaska, Sandra Castro, S. G. Djorgovski

This paper presents chemical abundance measurements for 12 new z>3 damped Lya systems discovered toward five quasars from the Palomar Sky Survey. We determine HI column densities from profile fits to the observed damped Lya profiles and measure ionic column densities and limits for all observed metal-line transitions. This dataset, acquired with the Echellet

Jason X. Prochaska, Eric Gawiser, Arthur M. Wolfe, Jeff Cooke

This paper presents chemical abundance measurements for 37 damped Lya systems at z>2.5 observed with the Echellette Spectrograph and Imager on the KeckII telescope. We measure the HI column densities of these damped systems through Voigt profile fits to their Lya profiles and we implement the apparent optical depth method to determine ionic column densities.

R. Luscher

The Boulby Dark Matter Collaboration (BDMC) is running a WIMP Dark Matter research programme in the underground laboratory of Boulby Mine. The two axes of the programme are based on (1) liquid Xenon (LXe) as the WIMP target and (2) directional detection in low pressure gas detectors. ZEPLIN-1 is a 3.1kg of LXe scintillation detector with a background discrim

D. Grupe, S. Mathur, M. Elvis

We report on the results of XMM-Newton observations of two Broad Absorption Line Quasars (BAL QSOs), Q1246-057 and SBS 1542+541. Unprecedented sensitivity of XMM allows spectral analysis of these X-ray weak sources. The X-ray spectral data of these sources can be fitted by a power-law with alpha_X=1.0-1.2 and either a partially covering absorber or an ionize