June 2006 arXiv papers — page 17

V. V. Begun, M. I. Gorenstein, M. Hauer, V. P. Konchakovski

The charged hadron multiplicity fluctuations are considered in the canonical ensemble. The microscopic correlator method is extended to include three conserved charges: baryon number, electric charge and strangeness. The analytical formulae are presented that allow to include resonance decay contributions to correlations and fluctuations. We make the predict

Thomas J. Buervenich, Joerg Evers, Christoph H. Keitel

The direct interaction of super-intense laser fields in the optical frequency domain with nuclei is studied. As main observable, we consider the nuclear AC-Stark shift of low-lying nuclear states due to the off-resonant excitation by the laser field. We include the case of accelerated nuclei to be able to control the frequency and the intensity of the laser

Mark J. Horner

We present the centrality dependence of the azimuthal angle correlation shapes between a trigger and associated charged hadrons in Au+Au collisions at $\sqrt{s_{NN}}=200$ GeV from the STAR experiment. The away-side structure is significantly modified in central collisions and is characterised in terms of a doubly-peaked yield. A minimum in the <$p_T$> of had

Patrick Achenbach, John H Cobb

A Monte Carlo simulation has been performed to track light rays in cylindrical multimode fibres by ray optics. The trapping efficiencies for skew and meridional rays in active fibres and distributions of characteristic quantities for all trapped light rays have been calculated. The simulation provides new results for curved fibres, where the analytical expre

Ingo Piepers

In this paper I propose a &#39;mechanism&#39; for the explanation of power-law characteristics of casualty dynamics in inter-state wars, intra-state wars and terrorist attacks: the scale-free physical organization of social systems. Other explanations - self-organized criticality (Cederman, 2003) and the redistribution of total attack capabilities (Johnson e

Norbert Marwan, Juergen Kurths, Peter Saparin

Recurrence plot based methods are highly efficient and widely accepted tools for the investigation of time series or one-dimensional data. We present an extension of the recurrence plots and their quantifications in order to study recurrent structures in higher-dimensional spatial data. The capability of this extension is illustrated on prototypical 2D model

Alexander Sakhnovich

Harmonic maps from $\BR^2$ or one-connected domain $Ø\subset \BR^2$ into $GL(m, \BC)$ and $U(m)$ are treated. The GBDT version of the Bäcklund-Darboux transformation is applied to the case of the harmonic maps. A new general formula on the GBDT transformations of the Sym-Tafel immersions is derived. A class of the harmonic maps similar in certain ways to lin

Victor J. Sanchez-Morcillo, J. Redondo, J. Martinez-Mora

We report a nonlinear acoustic system displaying excitability. The considered system is a magnetostrictive material where acoustic waves are parametrically generated. For a set of parameters, the system presents homoclinic and heteroclinic dynamics, whose boundaries define a excitability domain. The excitable behaviour is characterized by analyzing the respo

A. E. Hramov, A. A. Koronovskii, O. I. Moskalenko

This paper deals with two types of synchronous behavior of chaotic oscillators -- generalized synchronization and noise--induced synchronization. It has been shown that both these types of synchronization are caused by similar mechanisms and should be considered as the same type of the chaotic oscillator behavior. The mechanisms resulting in the generalized

Nikos I. Karachalios

Pointing out the difference between the Discrete Nonlinear Schrödinger equation with the classical power law nonlinearity-for which solutions exist globally, independently of the sign and the degree of the nonlinearity, the size of the initial data and the dimension of the lattice-we prove either global existence or nonexistence in time, for the Discrete Kle

Jacques H. H. Perk, Helen Au-Yang

Preprint of an Encyclopedia article (Encyclopedia of Mathematical Physics, eds. J.-P. Françoise, G.L. Naber and Tsou S.T., Oxford: Elsevier, 2006 (ISBN 978-0-1251-2666-3), volume 5, pages 465-473) extended with an appendix on relations of electric networks and solvable models. We welcome comments, especially on the added appendix. Please, note that the refer

Mohammed Daoud

We investigate a generalization of $A_r$ statistics discussed recently in the literature. The explicit complete set of state vectors for the $A_r$ statistics system is given. We consider a Bargmann or an analytic function description of the Fock space corresponding to $A_r$ statistics of bosonic kind. This brings, in a natural way, the so-called Gazeau-Klaud

Mohammed Daoud

The generalization of $A_r$ statistics, including bosonic and fermionic sectors, is performed by means of the so-called Jacobson generators. The corresponding Fock spaces are constructed. The Bargmann representations are also considered. For the bosonic $A_r$ statistics, two inequivalent Bargmann realizations are developed. The first (resp. second) realizati

Mohammed Daoud

A generalization of $A_r$ statistics is proposed and developed. The generalized $A_r$ quantum statistics is completely specified by a set of Jacobson generators satisfying a set of triple algebraic relations. Fock-Hilbert representations and Bargmann-Fock realizations are derived.

Vasily E. Tarasov

Fractional generalization of an exterior derivative for calculus of variations is defined. The Hamilton and Lagrange approaches are considered. Fractional Hamilton and Euler-Lagrange equations are derived. Fractional equations of motion are obtained by fractional variation of Lagrangian and Hamiltonian that have only integer derivatives.

Mitsuo Abe, Katsunori Kawamura

Previously, we have shown that the CAR algebra for fermions is embedded in the Cuntz algebra ${\cal O}_{2}$ in such a way that the generators are expressed in terms of polynomials in the canonical generators of the latter, and it coincides with the U(1)-fixed point subalgebra ${\cal A}\equiv {\cal O}_{2}^{U(1)}$ of ${\cal O}_{2}$ for the canonical gauge acti

Antonio Ramirez

Given a smooth closed manifold M with a family {L_i} of closed submanifolds, we consider the free loop space LM and the spaces PM(L_i,L_j) of open strings (paths g:[0,1]->M with g(0) in L_i, and g(1) in L_j). We construct string topology operations resulting in an open-closed TQFT on the family (h_*(LM),h_*(PM(L_i,L_j)) which extends the known string topolog

Andrew R. Kustin, Adela N. Vraciu

Let $k$ be a field of positive characteristic $p$, $R$ be a Gorenstein graded $k$-algebra, and $S=R/J$ be an artinian quotient of $R$ by a homogeneous ideal. We ask how the socle degrees of $S$ are related to the socle degrees of $F_R^e(S)=R/J^{[q]}$. If $S$ has finite projective dimension as an $R$-module, then the socles of $S$ and $F_R^e(S)$ have the same

M. Kwasnicki

A lower bound estimate λ_2 - λ_1 \ge c λ_1^{-d / α} (\diam D)^{-d - α} for the spectral gap of the Dirichlet fractional Laplacian on arbitrary bounded domain D is proved. This follows from a variational formula for the spectral gap and an upper bound estimate for the supremum norm of the ground state eigenfunction.

Michael P. Lamoureux, James A. Mingo

Let theta = p/q with p and q relatively prime and u and v a pair of unitaries such that u v = e^{i theta} v u, where u and v generate the rotation C*-algebra A_theta. Let h_{theta, lambda} = u + u^{-1} + lambda/2(v + v^{-1}) be the almost Mathieu operator. By proving an identity of rational functions we show that for q even, the constant term in the characte

Wei-Ping Li, Zhenbo Qin

Given a projetive surface $S$, using correspondences, we construct an infinite dimensional Lie algebra that acts on the direct sum $\Wfock$ of the cohomology groups of the incidence Hilbert schemes $S^{[n,n+1]}$ over all $n$. The algebra is related to an extension of an infinite dimensional Heisenberg algebra. The space $\Wfock$ is a highest weight represent

Metod Saniga, Michel Planat, Petr Pracna

A list of different types of a projective line over non-commutative rings with unity of order up to thirty-one inclusive is given. Eight different types of such a line are found. With a single exception, the basic characteristics of the lines are identical to those of their commutative counterparts. The exceptional projective line is that defined over the no

Ivy Jansen, Caroline Beunckens, Geert Molenberghs, Geert Verbeke

Commonly used methods to analyze incomplete longitudinal clinical trial data include complete case analysis (CC) and last observation carried forward (LOCF). However, such methods rest on strong assumptions, including missing completely at random (MCAR) for CC and unchanging profile after dropout for LOCF. Such assumptions are too strong to generally hold. O

Andrea Sorbi, Sebastiaan A. Terwijn

We investigate the initial segments of the Medvedev lattice as Brouwer algebras, and study the propositional logics connected to them.

Y. Zhao, J. Staudenmayer, B. A. Coull, M. P. Wand

Linear mixed models are able to handle an extraordinary range of complications in regression-type analyses. Their most common use is to account for within-subject correlation in longitudinal data analysis. They are also the standard vehicle for smoothing spatial count data. However, when treated in full generality, mixed models can also handle spline-type sm

Xavier Massaneda, Pascal J. Thomas

We propose a definition of sampling set for the Nevanlinna class in the disk, i.e. a subset of the disk such that the analogue of the norm of a function in the Nevanlinna class can be recovered only from its values on the subset. We show it is equivalent with the notion of determination set for the same class, that is, subsets such that any function in the c

Genady Ya. Grabarnik, Larisa Shwartz

Classical Banach principle is an essential tool for the investigation of the ergodic properties of Cesaro subsequences. The aim of this work is to extend Banach principle to the case of the stochastic convergence in the operator algebras. We start by establishing a sufficient condition for the stochastic convergence (stochastic Banach principle). Then we for

A. A. Lopatin

The least upper bound on degrees of elements of a minimal system of generators of the algebra of invariants of 3x3 matrices is found, and the nilpotency degree of a relatively free finitely generated algebra with the identity x^3=0 is established.

Le Anh Vinh

In this paper we study random walks on the hypergroup of conics in finite fields. We investigate the behavior of random walks on this hypergroup, the equilibrium distribution and the mixing times. We use the coupling method to show that the mixing time of random walks on hypergroup of conics is only linear.

Christine Vespa

In this paper, we define the functor category Fquad associated to vector spaces over the field with two elements, F\_2, equipped with a quadratic form. We show the existence of a fully-faithful, exact functor ι: \F \to Fquad, which preserves simple objects, where \F is the category of functors from the category of finite dimensional F\_2-vector spaces to the

Le Anh Vinh

A divisor graph $G$ is an ordered pair $(V, E)$ where $V \subset \mathbbm{Z}$ and for all $u \neq v \in V$, $u v \in E$ if and only if $u \mid v$ or $v \mid u$. A graph which is isomorphic to a divisor graph is also called a divisor graph. In this note, we will prove that for any $n \geqslant 1$ and $0 \leqslant m \leqslant \binom{n}{2}$ then there exists a

Le Anh Vinh

The quadrance between two points $A_1 = (x_1, y_1)$ and $A_2 = (x_2, y_2)$ is the number $Q (A_1, A_2) = (x_1 - x_2)^2 + (y_1 - y_2)^2$. Let $q$ be an odd prime power and $F_q$ be the finite field with $q$ elements. The unit-quadrance graph $D_q$ has the vertex set $F_q^2$, and $X, Y \in F_q^2$ are adjacent if and only if $Q (A_1, A_2) = 1$. In this paper, w

William Y. C. Chen, Deheng Xu

By a re-examination of MacMahon&#39;s original proof of his celebrated theorem on the distribution of the major indices over permutations, we give a reformulation of his argument in terms of the structure of labeled partitions. In this framework, we are able to establish a decomposition theorem for labeled partitions that leads to a simple bijective proof of

Wei Zhu

By the method of discrete Morse flows, we construct an energy reducing multiple-valued function flow. The flow we get is Holder continuous with respect to the L-2 norm. We also give another way of constructing flows in some special cases, where the flow we get behaves like ordinary heat flow.

Toshiaki Maeno

This paper has been withdrawn.

Michael Baake, Uwe Grimm

Planar coincidence site lattices and modules with N-fold symmetry are well understood in a formulation based on cyclotomic fields, in particular for the class number one case, where they appear as certain principal ideals in the corresponding ring of integers. We extend this approach to multiple coincidences, which apply to triple or multiple junctions. In p

Aicke Hinrichs, Erich Novak

We study cubature formulas for d-dimensional integrals with an arbitrary symmetric weight function of tensor product form. We present a construction that yields a high polynomial exactness: for fixed degree l=5 or l=7 and large dimension, the number of knots is only slightly larger than the lower bound of Möller and much smaller compared to the known constru

P. M. H. Wilson

Given a real cubic form f(x,y,z), there is a pseudo-Riemannian metric given by its Hessian matrix, defined on the open subset of R^3 where the Hessian determinant h is non-zero. We determine the full curvature tensor of this metric in terms of h and the S-invariant of f, obtaining in the process various different characterizations of S. Motivated by the case

C-Y. Jean Chan, I-Chiau Huang

Let A be the ring obtained by localizing the polynomial ring k[X,Y,Z,W] over a field k at the maximal ideal (X,Y,Z,W) and modulo the ideal (XW-YZ). Let p be the ideal of A generated by X and Y. We study the module structure of a minimal injective resolution of A/p in details using local cohomology. Applications include the description of Ext^i(M,A/p), where

M. Ishikawa, F. Jouhet, J. Zeng

An infinite summation formula of Hall-Littlewood polynomials due to Kawanaka is generalized to a finite summation formula, which implies, as applications, twelve multiple q-identities of Rogers-Ramanujan type.

V H Satheesh Kumar, P K Suresh

The idea that quantum gravity can be realized at the TeV scale is extremely attractive to theorists and experimentalists alike. This proposal leads to extra spacial dimensions large compared to the electroweak scale. Here we give a very systematic view of the foundations of the theories with large extra dimensions and their physical consequences.

Davide Astolfi, Valentina Forini, Gianluca Grignani, Gordon W. Semenoff

We compute the planar finite size corrections to the spectrum of the dilatation operator acting on two-impurity states of a certain limit of conformal $\mathcal{N}=2$ quiver gauge field theory which is a $Z_M$-orbifold of $\mathcal{N}=4$ supersymmetric Yang-Mills theory. We match the result to the string dual, IIB superstrings propagating on a pp-wave backgr

S. Lievens, N. I. Stoilova, J. Van der Jeugt

We consider a quantum system consisting of a one-dimensional chain of M identical harmonic oscillators with natural frequency $ω$, coupled by means of springs. Such systems have been studied before, and appear in various models. In this paper, we approach the system as a Wigner Quantum System, not imposing the canonical commutation relations, but using inste

Tim R. Morris, Oliver J. Rosten

Building on recent work in SU(N) Yang-Mills theory, we construct a manifestly gauge invariant exact renormalization group for QCD. A gauge invariant cutoff is constructed by embedding the physical gauge theory in a spontaneously broken SU(N|N) gauge theory, regularized by covariant higher derivatives. Intriguingly, the construction is most efficient if the n

G. W. Gibbons, M. J. Perry, C. N. Pope

We reformulate the Bekenstein bound as the requirement of positivity of the Helmholtz free energy at the minimum value of the function L=E- S/(2πR), where R is some measure of the size of the system. The minimum of L occurs at the temperature T=1/(2πR). In the case of n-dimensional anti-de Sitter spacetime, the rather poorly defined size R acquires a precise

Waldemar Berej, Jerzy Matyjasek, Dariusz Tryniecki, Mariusz Woronowicz

The first-order correction of the perturbative solution of the coupled equations of the quadratic gravity and nonlinear electrodynamics is constructed, with the zeroth-order solution coinciding with the ones given by Ayón-Beato and Garc{\&#39;ı}a and by Bronnikov. It is shown that a simple generalization of the Bronnikov&#39;s electromagnetic Lagrangian lead

Noriaki Kitazawa

The possibility of radiative gauge symmetry breaking on D3-branes at non-supersymmetric orbifold singularities is examined. As an example, a simple model of D3-branes at non-supersymmetric C^3/Z_6 singularity with some D7-branes for the cancellations of R-R tadpoles in twisted sectors is analyzed in detail. We find that there are no tachyon modes in twisted

Kentaro Hori, Johannes Walcher

We construct and classify categories of D-branes in orientifolds based on Landau-Ginzburg models and their orbifolds. Consistency of the worldsheet parity action on the matrix factorizations plays the key role. This provides all the requisite data for an orientifold construction after embedding in string theory. One of our main results is a computation of to

V. P. Efrosinin

With usage of the Low theorem the general expression for amplitude of radiative kaon decay \k+ \to π+\pi0γis determined.

A. R. Haghpayma

Although the Theta has been listed as a three star resonance in the 2004 PDG,its existence is still not completely established. Now it is still of interest to see what QCD has to say on the subject, In this paper we review briefly the pentaquark Theta properties.

V. A. Khoze, A. D. Martin, M. G. Ryskin

In principle, leading neutrons produced in photoproduction and deep-inelastic scattering at HERA have the potential to determine the pion structure function, the neutron absorptive cross section and the form of the pion flux. To explore this potential we compare theoretical predictions for the x_L and p_t spectra of leading neutrons, and the Q^2 dependence o

Christiana Athanasiou, Christopher G. Lester, Jennifer M. Smillie, Bryan R. Webber

We extend our earlier study of spin correlations in the decay chain $D\to C q$, $C\to B l^{near}$, $B\to A l^{far}$, where $A,B,C,D$ are new particles with known masses but undetermined spins, $l^{near}$ and $l^{far}$ are opposite-sign same-flavour charged leptons and $A$ is invisible. Instead of looking at the observable 2- and 3-particle invariant mass dis

George Sterman, Werner Vogelsang

We show that certain general properties of threshold and joint resummations in Drell-Yan cross sections hold as well for their crossed analogs in semi-inclusive deep-inelastic scattering and double-inclusive leptonic annihilation. We show that all plus-distribution corrections near threshold show the same structure, and are determined to all logarithmic orde

Xavier Calmet, Josep F. Oliver

In this letter we revisit the seesaw Higgs mechanism. We show how a seesaw mechanism in a two Higgs doublets model can trigger the electroweak symmetry breaking if at least one of the eigenvalues of the squared mass matrix is negative. We then consider two special cases of interest. In the decoupling scenario, there is only one scalar degree of freedom in th

BES Collaboration, M. Ablikim

A broad peak is observed at low K^+K^- invariant mass in J/psi --> K^+K^-pi^0 decays found in a sample of 5.8\times 10^7 J/psi events collected with the BESII detector. A partial wave analysis shows that the J^PC of this structure is 1^--. Its pole position is determined to be (1576^{+49}_{-55}(stat)^{+98}_{-91}(syst)) MeV/c^2 - i(409^{+11}_{-12}$(stat)^{+32

Stefan Kluth

Experimental studies of power corrections with e+e- data are reviewed. An overview of the available data for jet and event shape observables is given and recent analyses based on the Dokshitzer-Marchesini-Webber (DMW) model of power corrections are summarised. The studies involve both distributions of the observables and their mean values. The agreement betw

M. J. Wilking

We present recent preliminary results from five decay channels. From the $K_L\toπ^+π^-γ$ channel, we extract form factors for the CP violating M1 direct photon emission amplitude and the fraction of the total decay amplitude that is due to direct emission. We have placed an upper limit on the $K_L\toπ^0π^0γ$ branching ratio, and preliminary measurements of t

Mikhail V. Gorbatenko, Taras M. Gorbatenko

The paper presents equations determining the particle spin evolution in the post-Newtonian approximation in the problem of motion of two mass and spin possessing particles. The equations are derived with the Einstein-Infeld-Hoffmann method from the condition of metric tensor symmetry. The consideration uses the condition of coordinate harmonicity and the met

Chris Snow, Lutz Lampe, Robert Schober

Several recent standards such as IEEE 802.11a/g, IEEE 802.16, and ECMA Multiband Orthogonal Frequency Division Multiplexing (MB-OFDM) for high data-rate Ultra-Wideband (UWB), employ bit-interleaved convolutionally-coded multicarrier modulation over quasi-static fading channels. Motivated by the lack of appropriate error rate analysis techniques for this popu

Charis Ermopoulos, William Yurcik

In the UNIX/Linux environment the kernel can log every command process created by every user with process accounting. Thus process accounting logs have many potential uses, particularly the monitoring and forensic investigation of security events. Previous work successfully leveraged the use of process accounting logs to identify a difficult to detect and da

Paulo A. Condado, Fernando G. Lobo

Text-to-speech technology has been broadly used to help people with voice disabilities to overcome their difficulties. With text-to-speech, a person types at a keyboard, the text is synthesized, and the sound comes out through the computer speakers. In recent years, Voice over IP (VoIP) applications have become very popular and have been used by people world

Alain Denise, Marie-Claude Gaudel, Sandrine-Dominique Gouraud, Richard Lasseigne

This paper presents some first results on how to perform uniform random walks (where every trace has the same probability to occur) in very large models. The models considered here are described in a succinct way as a set of communicating reactive modules. The method relies upon techniques for counting and drawing uniformly at random words in regular languag

Boris Ryabko, Daniil Ryabko

We propose a simple universal (that is, distribution--free) steganographic system in which covertexts with and without hidden texts are statistically indistinguishable. The stegosystem can be applied to any source generating i.i.d. covertexts with unknown distribution, and the hidden text is transmitted exactly, with zero probability of error. Moreover, the

T. Kroll, A. A. Aligia, G. A. Sawatzky

In order to shed light on the electronic structure of Na_xCoO_2, and motivated by recent Co L-edge X-ray absorption spectra (XAS) experiments with polarized light, we calculate the electronic spectrum of a CoO_6 cluster including all interactions between 3d orbitals. We obtain the ground state for two electronic occupations in the cluster that correspond nom

Wan Kyu Park, Laura H. Greene, John L. Sarrao, Joe D. Thompson

Andreev reflection spectroscopy has been performed on the heavy-fermion superconductor (HFS) CeCoIn$_5$ single crystals along three different crystallographic orientations, (001), (110), and (100), using Au tips as counter-electrodes. Dynamic conductance spectra are reproducible over wide temperature ranges and consistent with each other, ensuring the spectr

Meta van Faassen, Kieron Burke

Time-dependent density functional theory is thought to work well for the test cases of He and Be atoms. We perform a quantum defect analysis of the s, p, and d Rydberg states of Be with accurate ground state Kohn-Sham potentials. The s- and p-quantum defects are well described by the ALDA, but fails badly for the d-quantum defect. The same failure is observe

Rodrigo Yoshikawa Oeiras, Marcos Veríssimo-Alves, Fernando M. Araújo-Moreira, Ricardo Faccio

We present ab initio calculations for single-atom vacancies in graphene. In agreement with earlier work, we find that vacancies are responsible for the magnetism recently observed experimentally, creating a center with net spin. For small supercells, there is a strong symmetry breaking in the supercell with respect to the perfect graphene structure, and this

V. V. Prudnikov, P. V. Prudnikov, A. S. Krinitsyn

We consider how the Pad&#39;e-Borel, Pad&#39;e-Borel-Leroy, and conformal mapping summation methods for asymptotic series can be used to calculate the dynamical critical exponent for homogeneous and disordered Ising-like systems.

E. Morosan, H. W. Zandbergen, B. S. Dennis, J. W. G. Bos

Charge density waves (CDWs) are periodic modulations of the conduction electron density in solids. They are collective states that arise from intrinsic instabilities often present in low dimensional electronic systems. The layered dichalcogenides are the most well-studied examples, with TiSe_2 one of the first CDW-bearing materials known. The competition bet

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

In the paper &#34; Superconducting decay length in a ferromagnetic metal&#34; by Gusakova, Kupriyanov and Golubov [Pis&#39;ma v ZhETF 83, 487 (2006); cond-mat/0605137], the authors claim that they solved the linearized Eilenberger equation in the ferromagnetic region of an S/F heterostructure at arbitrary mean free path. In this comment we show that the solu

Tony S. Yu, Eric Lauga, A. E. Hosoi

A simple way to generate propulsion at low Reynolds number is to periodically oscillate a passive flexible filament. Here we present a macroscopic experimental investigation of such a propulsive mechanism. A robotic swimmer is constructed and both tail shape and propulsive force are measured. Filament characteristics and the actuation are varied and resultin

Andrea Puglisi, Lamberto Rondoni, Angelo Vulpiani

Numerical observations on a Markov chain and on the continuous Markov process performed by a granular tracer show that the ``usual&#39;&#39; fluctuation relation for a given observable is not verified for finite (but arbitrarily large) times. This suggests that some terms which are usually expected to be negligible, i.e. ``border terms&#39;&#39; dependent on

Georges ~Bouzerar, Timothy Ziman, Josef Kudrnovský

We present a quantitative theory for ferromagnetism in diluted III-V ferromagnetic semi-conductors in the presence of the two types of defects commonly supposed to be responsible for compensation: As anti-sites and Mn interstitials. In each case we reduce the description to that of an effective random Heisenberg model with exchange integrals between active m

M. S. da Luz, C. A. M. dos Santos, B. Ferreira, A. J. S. Machado

In this work we have investigated the orthorhombic to tetragonal phase transition in the Ba2Cu3O4Cl2 compound. This transition was observed by X-ray powder diffractometry carried out in samples heat treated between 700 and 750OC and also in samples with Ba2ZnCu2O4Cl2 composition. Results of X-ray diffractograms simulation confirm the phase transition. dc-Mag

Georges ~Bouzerar, Richard Bouzerar, Josef ~Kudrnovský, Timothy Ziman

Using a recently developed semi-analytical method (Self-Consistent Local RPA or SC-LRPA) we study the stability of the ferromagnetic phase in diluted magnetic systems where the exchange coupling between magnetic impurities are of RKKY form. A short discussion of the relevance of these calculations with respect to the ferromagnetism observed in diluted ferrom

M. Sztyren

The present paper is an extension of &#39;cond-mat/0312673&#39;. The construction of a hybrid discrete-continuous model of layered superconductors is presented. The model bases on the classic Lawrence-Doniach scenario with admitting, however, long-range interactions between atomic planes. Moreover, apart from Josephson couplings they involve the proximity ef

S. H. Naqib, J. R. Cooper, R. S. Islam

We have studied the magnetic field dependence of the temperature derivative of the resistivity, dr(H,T)/dT, of a number of Y1-xCaxBa2(Cu1-yZny)3O7-d crystalline thin films over a wide range of sample compositions. From the analysis of the temperature derivative data we have been able to distinguish quite clearly between two characteristic temperature scales,

S. H. Naqib, J. R. Cooper

The effects of planar hole content, p, on the temperature-dependent uniform (q = 0) magnetic susceptibility, c(T), of polycrystalline Y1-xCaxBa2Cu3O7-d compounds with 0.0 </= x </= 0.20 were investigated over a wide range of oxygen deficiency (d). Systematic variations in c(T) were found with changing p. The characteristic pseudogap temperature scale, Eg(p)/

T. Kroll, M. Knupfer, J. Geck, C. Hess

Measurements of polarization and temperature dependent soft x-ray absorption have been performed on Na_xCoO_2 single crystals with x=0.4 and x=0.6. They show a deviation of the local trigonal symmetry of the CoO_6 octahedra, which is temperature independent in a temperature range between 25 K and 372 K. This deviation was found to be different for Co^{3+} an

R. G. Mani, W. B. Johnson, V. Umansky, V. Narayanamurti

An experimental study of the high mobility GaAs/AlGaAs system at large-$ν$ indicates several distinct phase relations between the oscillatory diagonal- and Hall- resistances, and suggests a new class of integral quantum Hall effect, which is characterized by &#34;anti-phase&#34; Hall- and diagonal- resistance oscillations.

I. Ali, D. Marenduzzo, J. M. Yeomans

We use a mesoscale simulation approach to explore the impact of different capsid geometries on the packaging and ejection dynamics of polymers of different flexibility. We find that both packing and ejection times are faster for flexible polymers. For such polymers a sphere packs more quickly and ejects more slowly than an ellipsoid. For semiflexible polymer

T. Hanney, R. B. Stinchcombe

We introduce a real-space renormalisation group procedure for driven diffusive systems which predicts both steady state and dynamic properties. We apply the method to the boundary driven asymmetric simple exclusion process and recover exact results for the steady state phase diagram, as well as the crossovers in the relaxation dynamics for each phase.

B. Szafran, S. Bednarek, F. M. Peeters

Binding of few-electron systems in two-dimensional potential cavities in the presence of an external magnetic field is studied with the exact diagonalization approach. We demonstrate that for shallow cavities the few-electron system becomes bound only under the application of a strong magnetic field. The critical value of the depth of the cavity allowing the

O. Vavra, S. Gazi, D. S. Golubovic, I. Vavra

We have studied temperature and field dependencies of the critical current $I_{C}$ in the Nb-Fe$_{0.1}$Si$_{0.9}$-Nb Josephson junction with tunneling barrier formed by paramagnetic insulator. We demonstrate that in these junctions the co-existence of both the 0 and the $π$ states within one tunnel junction takes place which leads to the appearance of a shar

Michael P. Allen, Friederike Schmid

A thermostat of the Nose-Hoover type, based on relative velocities and a local definition of the temperature, is presented. The thermostat is momentum-conserving and Galilean-invariant, which should make it suitable for use in Dissipative Particle Dynamics simulations, as well as nonequilibrium molecular dynamics simulations.

Dario F. Martinez, Rafael A. Molina

We generalize the definition of localization length to disordered systems driven by a time-periodic potential using a Floquet-Green function formalism. We study its dependence on the amplitude and frequency of the driving field in a one-dimensional tight-binding model with different amounts of disorder in the lattice. As compared to the autonomous system, th

M. R. Ghadimi, M. Fecioru-Morariu, B. Beschoten, G. Guentherodt

In epitaxially grown CoO(111)/Co(111) bilayers we have determined the blocking temperature distribution f(Tb), which is correlated with the antiferromagnetic domain size (z) distribution f(z). The latter is probed by reversing antiferromagnetic domains at successively higher temperatures in the reversed cooling field. The implementation of nonmagnetic defect

V. Kaufman, B. Drossel

Random Boolean networks were introduced in 1969 by Kauffman as a model for gene regulation. By combining analytical arguments and efficient numerical simulations, we evaluate the properties of relevant components of critical random Boolean networks independently of update scheme. As known from previous work, the number of relevant components grows logarithmi

Young Min Lee, Jun Hayakawa, Shoji Ikeda, Fumihiro Matsukura

We investigated the relationship between tunnel magnetoresistance (TMR) ratio and the crystallization of CoFeB layers through annealing in magnetic tunnel junctions (MTJs) with MgO barriers that had CoFe/Ru/CoFeB synthetic ferrimagnet pinned layers with varying Ru spacer thickness (tRu). The TMR ratio increased with increasing annealing temperature (Ta) and

Manabu Kiguchi, Kei Murakoshi

We have mechanically fabricated a Pd nanowire in solution under electrochemical potential control. A clear feature appeared in the conductance histogram when the electrochemical potential of the Pd wire was kept at the hydrogen evolution potential. Conductance traces showed the Pd wire was stretched 0.4 nm in length just before breaking, suggesting that at l

Xia-Ji Liu, Hui Hu

We discuss the superfluid phase transition of a strongly interacting Fermi gas with unequal (asymmetric) chemical potentials in two pairing hyperfine states, and map out its phase diagram near the BCS-BEC crossover. Our approach includes the fluctuation contributions of {}``preformed Cooper pairs&#39;&#39; to the thermodynamic potential at finite temperature

T. A. Sedrakyan, E. G. Mishchenko, M. E. Raikh

We develop an analytical theory of polarization of a vertically aligned array of carbon nanotubes (NTs) in external electric field. Such arrays are commonly utilized in field-emission devices, due to the known electrostatic effect of strong field enhancement near the tip of an individual NT. A small ratio of the NT radius to the separation between neighborin

S. Nordhagen, W. Herbst, E. C. Williams, E. Semkov

The recurrence of a previously documented eclipse of a solar-like pre--main-sequence star in the young cluster IC 348 has been observed. The recurrence interval is 4.7 $\pm 0.1$ yr and portions of 4 cycles have now been seen. The duration of each eclipse is at least 3.5 years, or $\sim 75$% of a cycle, verifying that this is not an eclipse by a stellar compa

The Nearby Supernova Factory Collaboration, G. Aldering, P. Antilogus, S. Bailey

We report Nearby Supernova Factory observations of SN 2005gj, the second confirmed case of a &#34;hybrid&#34; Type Ia/IIn supernova. Our early-phase photometry of SN 2005gj shows that the interaction is much stronger than for the prototype, SN 2002ic. Our first spectrum shows a hot continuum with broad and narrow H-alpha emission. Later spectra, spanning ove

J. H. Groh, A. Damineli, M. Teodoro, C. L. Barbosa

We report the detection of 3 additional Wolf-Rayet stars in the young cluster Westerlund 1. They were selected as emission-line star candidates based on 1 micron narrow-band imaging of the cluster carried out at OPD/LNA (Brazil), and then confirmed as Wolf-Rayet stars by K-band spectroscopy performed at the 4.1 m SOAR telescope (Chile). Together with previou

Alon Retter, Bing Zhang, Lionel Siess, Amir Levinson

The planets capture model for the eruption of V838 Mon is discussed. We used three methods to estimate the location where the planets were consumed. There is a nice consistency for the results of the three different methods, and we find that the typical stopping / slowing radius for the planets is about 1Ro. The three peaks in the optical light curve of V838

Vincent L. Fish

A recent submillimeter line survey of Orion KL claimed detection of SiH. This paper reports on GBT observations of the 5.7 GHz Lambda-doubling transitions of SiH in Orion. Many recombination lines, including C164-delta, are seen, but SiH is not detected. The nondetection corresponds to an upper limit of 1.5 x 10^15 cm^-2 (4 sigma) for the beam-averaged colum

Louis-Benoit Desroches, Alexei V. Filippenko, Shai Kaspi, Ari Laor

We present optical observations of the low-luminosity Seyfert 1 nucleus of NGC 4395, as part of a multiwavelength reverberation-mapping program. Observations were carried out over two nights in 2004 April at Lick, Wise, and Kitt Peak Observatories. We obtained V-band and B-band photometry, and spectra over the range 3500-6800 Angstroms. Simultaneous Hubble S

Tomotsugu Goto

We report a discovery of a new high redshift quasar at $z=5.96$, observed with the FOCAS long-slit spectrograph on board the Subaru telescope. The spectrum shows strong and broad Ly$α$+NV emission lines with a sharp discontinuity to the blue side. A Ly$β$+OVI emission line is also detected, providing a consistent redshift measurement with the Ly$α$+NV emissi

Michael P. Muno, Casey Law, J. Simon Clark, Sean M. Dougherty

We present the diffuse X-ray emission identified in Chandra observations of the young, massive Galactic star cluster Westerlund 1. After removing point-like X-ray sources down to a completeness limit of 2e31 erg/s, we identify 3e34 erg/s (2--8 keV) of diffuse emission. The spatial distribution of the emission can be described as a slightly-elliptical Lorentz