December 2005 arXiv papers — page 23

Taras Radul, Dusan Repovs

We investigate some topological properties of a normal functor $H$ introduced earlier by Radul which is some functorial compactification of the Hartman--Mycielski construction HM. We prove that the pair ($HX$, HM$Y$) is homeomorphic to the pair $(Q,σ)$ for each nondegenerated metrizable compactum $X$ and each dense $σ$-compact subset $Y$.

Ali Ghaffari

Let $M(S)$ be the Banach algebra of all bounded regular Borel measures on a locally compact Hausdorff semitopological semigroup $S$ with variation norm and convolution as multiplication. We obtain necessary and sufficient conditions for $M(S)^{*}$ to have a topologically left invariant mean.

Usha N Bhosle

Let $M$ be the moduli space of generalized parabolic bundles (GPBs) of rank $r$ and degree $d$ on a smooth curve $X$. Let $M_{\bar L}$ be the closure of its subset consisting of GPBs with fixed determinant ${\bar L}$. We define a moduli functor for which $M_{\bar L}$ is the coarse moduli scheme. Using the correspondence between GPBs on $X$ and torsion-free s

S J Bhatt, H V Dedania

For a compactly generated LCA group $G$, it is shown that the set $H(G)$ of all generalized characters on $G$ equipped with the compact-open topology is a LCA group and $H(G) = \dg$ (the dual group of $G$) if and only if $G$ is compact. Both results fail for arbitrary LCA groups. Further, if $G$ is second countable, then the Gel'fand space of the commuta

Ramji Lal, R P Shukla

The concept of `topological right transversal' is introduced to study right transversals in topological groups. Given any right quasigroup $S$ with a Tychonoff topology $T$, it is proved that there exists a Hausdorff topological group in which $S$ can be embedded algebraically and topologically as a right transversal of a subgroup (not necessarily closed

Pu Zhang, Kai Zhao

Let $\T (0\leq α<n)$ be the singular and fractional integrals with variable kernel $Ω(x,z)$, and $[b,\T]$ be the commutator generated by $\T$ and a Lipschitz function $b$. In this paper, the authors study the boundedness of $[b,\T]$ on the Hardy spaces, under some assumptions such as the $L^r$-Dini condition. Similar results and the weak type estimates at th

ArtŪras Dubickas

Suppose that $\al>1$ is an algebraic number and $ξ>0$ is a real number. We prove that the sequence of fractional parts $\{ξ\al^n\},$ $n =1,2,3,...,$ has infinitely many limit points except when $\al$ is a PV-number and $ξ\in \Q(\al).$ For $ξ=1$ and $\al$ being a rational non-integer number, this result was proved by Vijayaraghavan.

Savita Bhatnagar

The aim of this paper is to study the algebra $AC_{p}$ of absolutely continuous functions $f$ on [0,1] satisfying $f(0) = 0, f&#39;\in L^{p} [0, 1]$ and the multipliers of $AC_{p}$.

Sebastien Foulle

Let K be an algebraically closed field of characteristic p>0 and let Sp(2m) be the symplectic group of rank m over K. The main theorem of this article gives the character of the rational simple Sp(2m)-modules with fundamental highest weight as an explicit alternating sum of characters of Weyl modules. One obtains several formulae for the dimensions of these

Necdet Batir

In this paper we investigate the series $\sum_{k = 1}^\infty \binom{3k}{k}^{-1}k^{-n}x^k$. Obtaining some integral representations of them, we evaluated the sum of them explicitly for $n = 0, 1, 2$.

Atsushi Fujioka, Jun-ichi Inoguchi

In this paper we introduce the notion of timelike surface with harmonic inverse mean curvature in 3-dimensional Lorentzian space forms, and study their fundamental properties.

Roumen Anguelov

The LULU operators, well known in the nonlinear multiresolution analysis of sequences, are extended to functions defined on continuous domain, namely, a real interval $Ω\subseteq\mathbb{R}$. Similar to their discrete counterparts, for a given $δ>0$ the operators $L_δ$ and $U_δ$ form a fully ordered semi-group of four elements. It is shown that the compositio

Stefan Adams, Jean-Bernard Bru, Wolfgang Koenig

We study a model of $ N $ mutually repellent Brownian motions under confinement to stay in some bounded region of space. Our model is defined in terms of a transformed path measure under a trap Hamiltonian, which prevents the motions from escaping to infinity, and a pair-interaction Hamiltonian, which imposes a repellency of the $N$ paths. In fact, this inte

Patrick McLean

A problem of linear surface waves discussed by Forbes(1984) initially gave rise to a singular integrodifferential equation over the real line. We have been able to transform this integrodifferential equation into a linear second order differential equation whose solution has been found explicitly in terms of the sine and cosine integral functions. Furthermor

Ryoichi Kobayashi

A new proof of the Second Main Theorem with truncation level 1 for Zariski-dense holomorphic curves into Abelian varieties, which has just been proved by Yamanoi [Y2], is presented. Our proof is based on the idea of the &#34;Radon transform&#34; introduced in [K2] combined with consideration on certain singular perturbation of the probability measures on the

Roberta Di Gennaro, Uwe Nagel

The homogenous ideals of curves in a double plane have been studied by Chiarli, Greco, Nagel. Completing this work we describe the equations of any curve that is contained in some quadric. As a consequence, we classify the Hartshorne-Rao modules of such curves.

Nadia Chiarli, Silvio Greco, Uwe Nagel

We investigate space curves with large cohomology. To this end we introduce curves of subextremal type. This class includes all subextremal curves. Based on geometric and numerical characterizations of curves of subextremal type, we show that, if the cohomology is ``not too small,&#39;&#39; then they can be parameterized by the union of two generically smoot

Uwe Nagel

The conjecture of Kalai, Kleinschmidt, and Lee on the number of empty simplices of a simplicial polytope is established by relating it to the first graded Betti numbers of the polytope. The proof allows us to derive explicit optimal bounds on the number of empty simplices of any given dimension. As a key result, we prove optimal bounds for the graded Betti n

Michael Eastwood, Petr Somberg, Vladimir Soucek

The Joseph ideal is a special ideal in the universal enveloping algebra of a simple Lie algebra. For the classical groups, its uniqueness is equivalent to the existence of tensors with special properties. The existence of these tensors is usually concluded abstractly but here we present explicit formulae. This allows a rather direct computation of a paramete

Bozhidar Z. Iliev, Sawa S. Manoff

Connections between Lie derivatives and the deviation equation has been investigated in spaces with affine connection. The deviation equations of the geodesics as well as deviation equations of non-geodesics trajectories have been obtained on this base. This is done via imposing certain conditions on the Lie derivatives with respect to the tangential vector

Jan Schepers

The stringy E-function for normal irreducible complex varieties with at worst log terminal singularities was introduced by Batyrev. It is defined by data from a log resolution. If the variety is projective and Gorenstein and the stringy E-function is a polynomial, Batyrev also defined the stringy Hodge numbers as a generalization of the Hodge numbers of nons

Jakub Duda

We generalize some results of Borwein, Burke, Lewis, and Wang to mappings with values in metric (resp. ordered normed linear) spaces. We define two classes of monotone mappings between an ordered linear space and a metric space (resp. ordered linear space): $K$-monotone dominated and cone-to-cone monotone mappings. First we show some relationships between th

Hidenori Katsurada, Rainer Schulze-Pillot

We derive explicit formulas for the action of the Hecke operator $T(p)$ on the genus theta series of a positive definite integral quadratic form and prove a theorem on the generation of spaces of Eisenstein series by genus theta series. We also discuss connections of our results with Kudla&#39;s matching principle for theta integrals.

Thomas Peternell

This paper continues the study of non-general type subvarieties begun in a joint paper with M.Schneider and A.Sommese (Int.L.Math. 10, 1999). We prove uniruledness of a projective manifold containing a submanifold not of general type whose normal bundle has positivity properties and moreover study the rational quotient. We also relate the fundamental groups

Ramon van Handel

We develop a method to prove almost global stability of stochastic differential equations in the sense that almost every initial point (with respect to the Lebesgue measure) is asymptotically attracted to the origin with unit probability. The method can be viewed as a dual to Lyapunov&#39;s second method for stochastic differential equations and extends the

Wee Liang Gan, Victor Ginzburg

We study a scheme M closely related to the set of pairs of n by n-matrices with rank 1 commutator. We show that M is a reduced complete intersection with n+1 irreducible components, which we describe. There is a distinguished Lagrangian subvariety Nil in M. We introduce a category, C, of D-modules whose characteristic variety is contained in Nil. Simple obje

Kim Dang Phung

We study the dissipative linear wave equation in a bounded domain. The exponential decay rate of the energy was established by Bardos, Lebeau and Rauch under a geometrical hypothesis linked with the geodesics. Furthermore such condition called geometric control condition is almost necessary to get a uniform exponential decay. In another hand, Lebeau proved a

Horatiu Nastase

We analyze the high energy scattering of hadrons in QCD in an effective theory model inspired from a gravity dual description. The nucleons are skyrmion-like solutions of a DBI action, and boosted nucleons give pions field shockwaves necessary for the saturation of the Froissart bound. Nuclei are analogs of BIon crystals, with the DBI skyrmions forming a flu

Rafael Hernandez, Konstadinos Sfetsos, Dimitrios Zoakos

We summarize our recent work on supergravity backgrounds dual to part of the Coulomb branch of N=1 theories constructed as marginal deformations of N=4 Yang-Mills. In particular, we present a summary of the behaviour of the heavy quark-antiquark potential which shows confining behaviour in the IR as well as of the spectrum of the wave equation. The reduced s

Iosif Bena, Chih-Wei Wang, Nicholas P. Warner

We construct smooth supergravity solutions describing a BPS black ring with a BPS black hole centered at an arbitrary distance above the ring. We find that as one moves the black hole the entropy of the ring remains constant, but the angular momentum coming from the supergravity fluxes changes. Our solutions also show that in order to merge a BPS black ring

Sachiko Oshima, Seiji Kanemaki, Takehisa Fujita

We examine the negative energy solution in Klein-Gordon equation in terms of the number of field components. A scalar field has only one component, and there is no freedom left for an anti-particle since the Klein-Gordon equation failed to take the negative energy solution into account. This is in contrast to the Dirac equation which has four components of f

S. Odake, R. Sasaki

The equilibrium positions of the multi-particle classical Calogero-Sutherland-Moser (CSM) systems with rational/trigonometric potentials associated with the classical root systems are described by the classical orthogonal polynomials; the Hermite, Laguerre and Jacobi polynomials. The eigenfunctions of the corresponding single-particle quantum CSM systems are

Vincent Bouchard, Ron Donagi

We introduce a new heterotic Standard Model which has precisely the spectrum of the Minimal Supersymmetric Standard Model (MSSM), with no exotic matter. The observable sector has gauge group SU(3) x SU(2) x U(1). Our model is obtained from a compactification of heterotic strings on a Calabi-Yau threefold with Z_2 fundamental group, coupled with an invariant

Duiliu-Emanuel Diaconescu, Bogdan Florea

We study geometric transitions for topological strings on compact Calabi-Yau hypersurfaces in toric varieties. Large N duality predicts an equivalence between topological open and closed string theories connected by an extremal transition. We develop new open string enumerative techniques and perform a high precision genus zero test of this conjecture for a

Nima Arkani-Hamed, Gordon L. Kane, Jesse Thaler, Lian-Tao Wang

Given experimental evidence at the LHC for physics beyond the standard model, how can we determine the nature of the underlying theory? We initiate an approach to studying the &#34;inverse map&#34; from the space of LHC signatures to the parameter space of theoretical models within the context of low-energy supersymmetry, using 1808 LHC observables including

Hooman Davoudiasl, Lisa L. Everett

We consider the possibility that the quark condensate formed by QCD confinement generates Majorana neutrino masses m_νvia dimension seven operators. No degrees of freedom beyond the Standard Model are necessary, below the electroweak scale. Obtaining experimentally acceptable neutrino masses requires the new physics scale Λ~ TeV, providing a new motivation f

G. A. Kozlov

We derive new features of Bose-Einstein correlations by means of Quantum Field Theory at finite temperature, supplemented by operator-field evolution approach. The origin of the dependence of the measured two-particle correlation function (as well as the so-called correlation radius) on the particle mass has received its correct explanation. The lower bound

R. Baldini Ferroli

BaBar has measured with unprecedented accuracy the e+e- --> ppbar cross section from the threshold up to Q^2 ~ 20 GeV^2/c^4, finding out an unexpected cross section, with plateaux and negative steps. Evidence for a ratio |G_E/G_M|>1 has also been found as well as a sudden variation in |G_M| just above the threshold.

I. Antoniadis

Lowering the string scale in the TeV region provides a theoretical framework for solving the mass hierarchy problem and unifying all interactions. The apparent weakness of gravity can then be accounted by the existence of large internal dimensions, in the submillimeter region, and transverse to a braneworld where our universe must be confined. I review the m

M. L. Nekrasov

The method of the top quark mass measurement from $M_{b l}$ distribution in $t \to b l ν$ decays can be considerably improved if applying the technique of moments and proceeding to moments of high degree. At the LHC this allows one to reduce the systematic and statistical errors of the top mass by more than a factor of two.

S. Dev, Sanjeev Kumar, Surender Verma

We perform the most general model independent analysis of the latest 391-Day Salt Phase SNO Data Set incorporating the Super-Kamiokande ES flux measurement and obtain bounds on the antineutrino and sterile neutrino flux in the solar $^{8}$B neutrino flux reaching the detectors on the earth. The muon/ tauon antineutrino flux is found to be disallowed at 1.4$σ

A. N. Ivanov, A. Ya. Berdnikov, Ya. A. Berdnikov, M. Faber

We analyse the angular distributions of the Sigma^0 --> Lambda^0 + gamma decay rate in the laboratory and in the rest frame of the Sigma^0 - hyperon in the dependence on baryon polarizations. We calculate the dynamical polarization vector of the Lambda^0 - hyperon. Within the Effective quark model with chiral U(3) x U(3) symmetry (PRC 59, 451 (1999)) we calc

I. F. Ginzburg, I. P. Ivanov

We suggest to measure Pomeron phase and discover odderon via the measurement of charge asymmetry of pions in the diffractive processes $ep\to eπ^+π^- p$, $eA\to eπ^+π^- A$ and in the processes $AA\to AAπ^+π^-$ with two rapidity gaps.

Aneesh V. Manohar

Effective field theory methods are used to study factorization of the deep inelastic scattering cross-section. The cross-section is shown to factor in QCD, even though it does not factor in perturbation theory for some choices of the infrared regulator. Messenger modes are not required in soft-collinear effective theory for deep inelastic scattering as x ->

Jonathan L. Feng, Arvind Rajaraman, Bryan T. Smith

We extend the parameter space of minimal supergravity to negative values of m_0^2, the universal scalar mass parameter defined at the grand unified scale. After evolving to the weak scale, all scalars can be non-tachyonic with masses consistent with collider constraints. This region of parameter space is typically considered excluded by searches for charged

Jay Hubisz, Seung J. Lee, Gil Paz

We analyze flavor constraints in the littlest Higgs model with T-parity. In particular, we focus on neutral meson mixing in the K, B, and D systems due to one loop contributions from T-parity odd fermions and gauge bosons. We calculate the short distance contributions to mixing for a general choice of T-odd fermion Yukawa couplings. We find that for a generi

V. K. Petrov

odel for studying coupling dependence on lattice spacing a in gluodynamics is suggested. The model predicts $g-> g_{0}>0 with a->0. Free energy density in the model does not depend on temperature.

Gunnar S Bali, Thomas Dussel, Thomas Lippert, Hartmut Neff

We numerically investigate the transition of the static quark-antiquark string into a static-light meson-antimeson system. Improving noise reduction techniques, we are able to resolve the signature of string breaking dynamics for Nf=2 lattice QCD at zero temperature. We discuss the lattice techniques used and present results on energy levels and mixing angle

Belle Collaboration

A study of transitions between $Υ$ states with the emission of charged pions using 398 fb$^{-1}$ of data collected with the Belle detector at the KEKB asymmetric energy $e^+e^-$ collider is presented. A clear peak from the decay $Υ(1S)\toμ^+μ^-$ is observed in the invariant mass distribution of $(μ^+ μ^-)$ pairs from the $(μ^+ μ^- π^+ π^- X)$ event sample. T

The GEM Collaboration, M. Lesiak, M. Abdel-Bary, A. Budzanowski

Measurement of the d + d -> 4He + eta reaction using vector and tensor polarised beam has been performed at COSY using Big Karl magnetic spectrograph. The beam polarisation necessary for obtaining the vector and tensor analysing power for this reaction was measured. The method and the results of the tensor polarisation measurement of the deuteron beam are pr

Ghulam Shabbir

A study of conformally flat but non flat Bianchi type I and cylindrically symmetric static space-times according to proper projective symmetry is given by using some algebraic and direct integration techniques. It is shown that the special class of the above space-times admit proper projective vector fields.

Yi Ling, Xiang Li, Hongbao Zhang

We study the thermodynamics of modified black holes proposed in the context of gravity&#39;s rainbow. A notion of intrinsic temperature and entropy for these black holes is introduced. In particular for a specific class of modified Schwarzschild solutions, their temperature and entropy are obtained and compared with those previously obtained from modified di

S. P. Dawson

Fewster and Mistry have given an explicit, non-optimal quantum weak energy inequality that constrains the smeared energy density of Dirac fields in Minkowski spacetime. Here, their argument is adapted to the case of flat, two-dimensional spacetime. The non-optimal bound thereby obtained has the same order of magnitude, in the limit of zero mass, as the optim

Chiranjeeb Buragohain, Divyakant Agrawal, Subhash Suri

We propose efficient distributed algorithms to aid navigation of a user through a geographic area covered by sensors. The sensors sense the level of danger at their locations and we use this information to find a safe path for the user through the sensor field. Traditional distributed navigation algorithms rely upon flooding the whole network with packets to

Roberto Amadio, Gerard Boudol, Ilaria Castellani, Frederic Boussinot

In this note we revisit the so-called reactive programming style, which evolves from the synchronous programming model of the Esterel language by weakening the assumption that the absence of an event can be detected instantaneously. We review some research directions that have been explored since the emergence of the reactive model ten years ago. We shall al

Roberto Amadio, Silvano Dal Zilio

We develop new methods to statically bound the resources needed for the execution of systems of concurrent, interactive threads. Our study is concerned with a \emph{synchronous} model of interaction based on cooperative threads whose execution proceeds in synchronous rounds called instants. Our contribution is a system of compositional static analyses to gua

Roberto Bagnara, Andrea Pescetti, Alessandro Zaccagnini, Enea Zaffanella

Fully automatic worst-case complexity analysis has a number of applications in computer-assisted program manipulation. A classical and powerful approach to complexity analysis consists in formally deriving, from the program syntax, a set of constraints expressing bounds on the resources required by the program, which are then solved, possibly applying safe a

Yi-Dong Shen, Danny De Schreye

The termination problem of a logic program can be addressed in either a static or a dynamic way. A static approach performs termination analysis at compile time, while a dynamic approach characterizes and tests termination of a logic program by applying a loop checking technique. In this paper, we present a novel dynamic approach to termination analysis for

Ion I. Mandoiu, Claudia Prajescu

Despite much progress over the past decade, current Single Nucleotide Polymorphism (SNP) genotyping technologies still offer an insufficient degree of multiplexing when required to handle user-selected sets of SNPs. In this paper we propose a new genotyping assay architecture combining multiplexed solution-phase single-base extension (SBE) reactions with seq

M. V. Cheremisin, G. G. Samsonidze

Taking into account both the scattering and the velocity saturation of carriers, we examine the &#34;shallow-water&#34; instability of the two-dimensional electron gas in a field effect transistor. It is shown that both the scattering (which is analogous to friction in a shallow-water channel) and the carrier velocity saturation lead to damping of the plasma

S. Khlebnikov

We show that the piezoelectric coupling to three-dimensional phonons in GaAs renormalizes the current-voltage exponent for tunneling of electrons into an incompressible quantum Hall edge. The leading correction is always negative, in agreement with experiments on the $ν= 1/3$ state and, depending on the precise value of the edge plasmon speed, can be as larg

J. Sugiyama, H. Nozaki, Y. Ikedo, K. Mukai

By means of muon spin spectroscopy, we have found that K$_{0.49}$CoO$_2$ crystals undergo successive magnetic transitions from a high-T paramagnetic state to a magnetic ordered state below 60 K and then to a second ordered state below 16 K, even though K_{0.49}CoO_2 is metallic at least down to 4 K. An isotropic magnetic behavior and wide internal-field dist

B. H. Hamadani, H. Ding, Y. Hao, D. Natelson

We have studied metal/organic semiconductor charge injection in poly(3-hexylthiophene) (P3HT) field-effect transistors with Pt and Au electrodes as a function of annealing in vacuum. At low impurity dopant densities, Au/P3HT contact resistances increase and become nonohmic. In contrast, Pt/P3HT contacts remain ohmic even at far lower doping. Ultraviolet phot

P. V. Prudnikov, V. V. Prudnikov

The field-theoretic description of dynamical critical effects of the influence of disorder on acoustic anomalies near the temperature of the second-order phase transition is considered for three-dimensional Ising-like systems. Calculations of the sound attenuation in pure and dilute Ising-like systems near the critical point are presented. The dynamical scal

A. Robledo

An account is given of the features, of the kind pertaining to q-statistics, of the dynamics at the one-dimensional critical attractors associated to the three familiar routes to chaos, intermittency, period doubling and quasiperiodicity. Connections between the properties of these attractors and those of systems with many degrees of freedom at extremal or t

Cristian V. Ciobanu, Ryan M. Briggs

We report atomic scale studies of the effect of applied strain and hydrogen environment on the reconstructions of the (105) Si and Ge surfaces. Surface energy calculations for monohydride-terminated (001) and (105) reconstructions reveal that the recently established single-height rebonded model is unstable not only with respect to (001), but also in compari

Rafi Bistritzer, Ady Stern

We consider the oscillating sign of the drag resistivity and its anomalous temperature dependence discovered experimentally in a bi-layer system in the regime of the integer quantum Hall effect. We attribute the oscillating sign to the effect of disorder on the relation between an adiabatic momentum transfer to an electron and the displacement of its positio

C. W. M. Castleton, A. Hoglund, S. Mirbt

The errors arising in ab initio density functional theory studies of semiconductor point defects using the supercell approximation are analyzed. It is demonstrated that a) the leading finite size errors are inverse linear and inverse cubic in the supercell size, and b) finite size scaling over a series of supercells gives reliable isolated charged defect for

Y. Ohta, T. Nakaegawa, S. Ejima

Quantum Monte Carlo and density-matrix renormalization group methods are used to study the coupled spin-pseudospin Hamiltonian in one-dimension (1D) that models the charge-ordering instability of the anisotropic Hubbard ladder at quarter filling. We calculate the temperature dependence of the uniform spin susceptibility and specific heat as well as the spin

David Sherrington

A brief review is given of the minority game, an idealized model stimulated by a market of speculative agents, and its complex many-body behaviour. Particular consideration is given to analytic results for the model rather than discussions of its relevance in real-world situations.

C. W. M. Castleton, S. Mirbt

The relaxed and unrelaxed formation energies of neutral antisites and interstitial defects in InP are calculated using ab initio density functional theory and simple cubic supercells of up to 512 atoms. The finite size errors in the formation energies of all the neutral defects arising from the supercell approximation are examined and corrected for using fin

D. Senff, F. Krueger, S. Scheidl, M. Benomar

The magnon dispersion in the charge, orbital and spin ordered phase in La(0.5)Sr(1.5)MnO(4) has been studied by means of inelastic neutron scattering. We find an excellent agreement with a magnetic interaction model basing on the CE-type superstructure. The magnetic excitations are dominated by ferromagnetic exchange parameters revealing a nearly-one dimensi

Francisco-Jose Perez-Reche, Felix Casanova, Eduard Vives, Lluis Manosa

We report on the existence of acoustic emission during the paramagnetic-monoclinic to ferromagnetic-orthorhombic magnetostructural phase transition in the giant magnetocaloric Gd5Si2Ge2 compound. The transition kinetics have been analyzed from the detected acoustic signals. It is shown that this transition proceeds by avalanches between metastable states.

Bogdana Borca, Olivier Fruchart, Claire Meyer

We report the fabrication of self-organized arrays of Fe nanostripes with a period of 3.5 nm, by sequential deposition of Fe and Ag on Mo(110). The wires display a strong in-plane uniaxial anisotropy along their length, and are superparamagnetic above Tb=185+/-15K. The large value of nucleation volumes, inferred from the analysis of the thermal dependence of

Thiebaud Richeton, Patrik Dobron, Frantisek Chmelik, Jerome Weiss

Previous acoustic emission (AE) experiments on ice single crystals, as well as numerical simulations, called for the possible occurrence of self-organized criticality (SOC) in collective dislocation dynamics during plastic deformation. Here, we report AE experiments on hcp metallic single crystals. Dislocation avalanches in relation with slip and twinning ar

Kartick Tarafder, Abhijit Mookerjee

We present here a calculation of the configuration averaged optical conductivity of random binary alloys CuAu and AgAu. Our formulation is based on the augmented space formalism proposed by Mookerjee [J. Phys. C : Solid State Phys. {\bf 6} 1340 (1973)] and the optical conductivity is obtained directly through a recursive procedure suggested by Viswanath and

Christian Flindt, Niels Asger Mortensen, Antti-Pekka Jauho

We propose a new structure suitable for quantum computing in a solid state environment: designed defect states in antidot lattices superimposed on a two-dimensional electron gas at a semiconductor heterostructure. State manipulation can be obtained with gate control. Model calculations indicate that it is feasible to fabricate structures whose energy level s

J. F. Fernandez, J. J. Alonso

We study systems of classical magnetic dipoles on simple cubic lattices with dipolar and antiferromagnetic exchange interactions. By analysis and Monte Carlo (MC) simulations, we find how the antiferromagnetic phases vary with uniaxial and fourfold anisotropy constants, C and D, as well as with exchange strength J. We pay special attention to the spin reorie

Andrea Montanari

These are the notes for two lectures delivered at the Les Houches summer school Mathematical Statistical Mechanics, held in July 2005. I review some basic notions on sparse graph error correcting codes with emphasis on `modern&#39; aspects, such as, iterative belief propagation decoding. Relations with statistical mechanics, inference and random combinatoria

Marc Mezard, Andrea Montanari

Consider an information source generating a symbol at the root of a tree network whose links correspond to noisy communication channels, and broadcasting it through the network. We study the problem of reconstructing the transmitted symbol from the information received at the leaves. In the large system limit, reconstruction is possible when the channel nois

C. L. Huang, C. C. Chou, C. J. Ho, C. P. Sun

The RMn2O5 (R=Pr, Nd, Sm, and Eu) oxides showing magnetoelectric (ME) behavior have been prepared in polycrystalline form by a standard citrate route. The lattice parameters, obtained from the powder XRD analysis, follow the rare-earth contraction indicating the trivalent character of the R ions. Cusp-like anomalies in the magnetic susceptibility curve and s

C. L. Huang, J. Y. Lin, C. P. Sun, T. K. Lee

The magnetic field dependence of low temperature specific heat in YNi2B2C was measured and analyzed using various pairing order parameters. At zero magnetic field, the two-gap model which has been successfully applied to MgB2 and the point-node model, appear to describe the superconducting gap function of YNi2B2C better than other models based on the isotrop

M. Bal, Jonathan R. Friedman, M. T. Tuominen, E. M. Rumberger

We describe an experiment aimed at measuring the spin dynamics of the Fe8 single-molecule magnet in the presence of pulsed microwave radiation. In earlier work, heating was observed after a 0.2-ms pulse of intense radiation, indicating that the spin system and the lattice were out of thermal equilibrium at millisecond time scale [Bal et al., Europhys. Lett.

J. Schnack, M. Brueger, M. Luban, P. Koegerler

We investigate the bulk magnetic, electron paramagnetic resonance, and magneto-optical properties of {Ni4Mo12}, a magnetic molecule with antiferromagnetically coupled tetrahedral {Ni4Mo12} in a diamagnetic molybdenum matrix. The low-temperature magnetization exhibits steps at irregular field intervals, a result that cannot be explained using a Heisenberg mod

Benjamin K. Cooper, Victor M. Yakovenko

Different types of angular magnetoresistance oscillations in quasi-one-dimensional layered materials, such as organic conductors (TMTSF)2X, are explained in terms of Aharonov-Bohm interference in interlayer electron tunneling. A two-parameter pattern of oscillations for generic orientations of a magnetic field is visualized and compared with the experimental

L. H. Yu, Z. K. Keane, J. W. Ciszek, L. Cheng

We report Kondo resonances in the conduction of single-molecule transistors based on transition metal coordination complexes. We find Kondo temperatures in excess of 50 K, comparable to those in purely metallic systems. The observed gate dependence of the Kondo temperature is inconsistent with observations in semiconductor quantum dots and a simple single-do

N. A. Buznikov, C. G. Kim, C. O. Kim, L. Jin

The off-diagonal magnetoimpedance in field-annealed CoFeSiB amorphous ribbons was measured in the low-frequency range using a pick-up coil wound around the sample. The asymmetric two-peak behavior of the field dependence of the off-diagonal impedance was observed. The asymmetry is attributed to the formation of a hard magnetic crystalline phase at the ribbon

Rupert A. C. Croft, A. J. Banday, Lars Hernquist

The intergalactic neutral hydrogen which is responsible for the Lyman alpha forest of quasar absorption is a tracer of much larger amounts of ionised hydrogen. The ionised component has yet to be detected directly, but is expected to scatter CMB photons via the Sunyaev-Zel&#39;dovich (SZ) effect. We use hydrodynamic simulations of a LambdaCDM universe to cre

S. P. Reynolds, K. J. Borkowski, B. M. Gaensler, N. Rea

We present the discovery of the first X-ray counterpart to a Rotating RAdio Transient (RRAT) source. RRAT J1819--1458 is a relatively highly magnetized (B $\sim 5\times10^{13}$ G) member of a new class of unusual pulsar-like objects discovered by their bursting activity at radio wavelengths. The position of RRAT J1819--1458 was serendipitously observed by th

J. B. Juin, D. Yvon, A. Refregier, C. Yeche

The cosmological potential of large-scale structure observations for cosmology have been extensively discussed in the litterature. In particular, it has recently been shown how Sunyaev-Zel&#39;dovich (SZ) cluster surveys can be used to constrain dark energy parameters. In this paper, we study whether selection and systematics effects will limit future wide-f

Stanislav Boldyrev, Farhad Yusef-Zadeh

A great deal of study has been carried out over the last twenty years on the origin of the magnetic activity in the Galactic center. One of the most popular hypotheses assumes milli-Gauss magnetic field with poloidal geometry, pervading the inner few hundred parsecs of the Galactic-center region. However, there is a growing observational evidence for the lar

J. H. Groh, D. J. Hillier, A. Damineli

We report the detection of broad absorptions due to Si IV 4088-4116 A in the Luminous Blue Variable (LBV) AG Carinae during its last hot phase (2001-2003). Our NLTE spectral analysis, with the radiative transfer code CMFGEN, revealed the photospheric nature of these lines predicting, however, much narrower and deeper absorption profiles than observed. Using

M. Jura, J. Bohac, B. Sargent, W. J. Forrest

We report spectra obtained with the Spitzer Space Telescope in the 5 to 35 micron range of HD 233517, an evolved K2 III giant with circumstellar dust. At wavelengths longer than 13 microns, the flux is a smooth continuum that varies approximately as frequency to the -5/3 power. For wavelengths shorter than 13 microns, although the star is oxygen-rich, PAH fe

Lifan Wang, Mark Strovink, Alexander Conley, Gerson Goldhaber

Published B and V fluxes from nearby Type Ia supernovae are fitted to light-curve templates with 4-6 adjustable parameters. Separately, B magnitudes from the same sample are fitted to a linear dependence on B-V color within a post-maximum time window prescribed by the CMAGIC method. These fits yield two independent SN magnitude estimates B_max and B_BV. Thei

Dipak Munshi, Patrick Valageas

We study the possibility of using the entire probability distribution function (PDF) of the aperture mass Map and its related cumulative probability distribution function (CPDF) to obtain meaningful constraints on cosmological parameters. Deriving completely analytic expressions for the associated covariance matrices, we construct the Fisher matrix and use i

M. Rejkuba, G. S. Da Costa, H. Jerjen, M. Zoccali

We study the red giant populations of two dE galaxies, AM 1339-445 and AM 1343-452, with the aim of investigating the number and luminosity of any upper asymptotic giant branch (AGB) stars present. The galaxies are members of the Centaurus A group (D~3.8 Mpc) and are classified as outlying (R~350 kpc) satellites of Cen A. The analysis is based on near-IR pho

E. Roediger, M. Brueggen

We present 3D hydrodynamical simulations of ram pressure stripping of massive disc galaxies in clusters. Studies of galaxies that move face-on have predicted that in such a geometry the galaxy can lose a substantial amount of its interstellar medium. But only a small fraction of galaxies is moving face-on. Therefore, in this work we focus on a systematic stu

G. J. Harris, J. Tennyson, B. M. Kaminsky, Ya. V. Pavlenko

We build an accurate database of 5200 HCN and HNC rotation-vibration energy levels, determined from existing laboratory data. 20~000 energy levels in the Harris et al. (2002) linelist are assigned approximate quantum numbers. These assignments, lab determined energy levels and Harris et al (2002) energy levels are incorporated in to a new energy level list.

M. Maercker, M. G. Burton, C. M. Wright

We present a JHKL survey of the massive star forming region RCW 57 (NGC 3576) based on L-band data at 3.5 micron taken with SPIREX (South Pole Infrared Explorer), and 2MASS JHK data at 1.25-2.2 micron. This is the second of two papers, the first one concerning a similar JHKL survey of 30 Doradus. Colour-colour and colour-magnitude diagrams are used to detect

M. Gilfanov, M. Revnivtsev

We show that aperiodic and quasiperiodic variability of bright LMXBs - atoll and Z- sources, on ~sec - msec time scales is caused primarily by variations of the boundary layer luminosity. The accretion disk emission is less variable on these time scales and its power density follows 1/f law, contributing to observed flux variation at low frequencies and low