November 2005 arXiv papers — page 21

G. Caliskan, C. Hyeon, U. Perez-Salas, R. M. Briber

We determine the persistence length, $l_p$, for a bacterial group I ribozyme as a function of concentration of monovalent and divalent cations by fitting the distance distribution functions $P(r)$ obtained from small angle X-ray scattering intensity data to the asymptotic form of the calculated $P_{WLC}(r)$ for a worm-like chain (WLC). The $l_p$ values chang

Sandra Kanani, Alain Pumir, Valentine Krinsky

Artificial biological pacemakers were developed and tested in canine ventricles. Next steps will require obtaining oscillations sensitive to external regulations, and robust with respect to long term drifts of expression levels of pacemaker currents and gap junctions. We introduce mathematical models intended to be used in parallel with the experiments. The

Sandy Yang, Takeshi Yamamoto, William H. Miller

The quantum instanton approximation is a type of quantum transition state theory that calculates the chemical reaction rate using the reactive flux correlation function and its low order derivatives at time zero. Here we present several path-integral estimators for the latter quantities, which characterize the initial decay profile of the flux correlation fu

Gordon Chalmers

A compression algorithm is presented that uses the set of prime numbers. Sequences of numbers are correlated with the prime numbers, and labeled with the integers. The algorithm can be iterated on data sets, generating factors of doubles on the compression.

Vasily E. Tarasov, George M. Zaslavsky

We derive the fractional generalization of the Ginzburg-Landau equation from the variational Euler-Lagrange equation for fractal media. To describe fractal media we use the fractional integrals considered as approximations of integrals on fractals. Some simple solutions of the Ginzburg-Landau equation for fractal media are considered and different forms of t

R. Annou, B. Ferhat

A bifurcation of strong shock waves front for xenon in a shock tube has been noted. We propose a model which explains the effect and gives a variation-law of the front shape with respect to the Mach number M and the unperturbed gas pressure p1.

M. Ebrahim Fouladvand, M. Reza Shaebani, Zeinab Sadjadi

We propose a two dimensional probabilistic cellular automata for the description of traffic flow in a small city network composed of two intersections. The traffic in the network is controlled by a set of traffic lights which can be operated both in fixed-time and a traffic responsive manner. Vehicular dynamics is simulated and the total delay experienced by

L. Pal, M. Makai

Alerting experience with a well-acknowledged safety analysis code initiated the authors to pay attention to safety issues of complex systems. Their first concern was the statistical characteristics of such a code. We point out a remarkable weakness of the so called 0.95/0.95 methodology: when repeating the search for the tolerance limit, we get a higher valu

Vasily E. Tarasov, George M. Zaslavsky

The notion of fractional dynamics is related to equations of motion with one or a few terms with derivatives of a fractional order. This type of equation appears in the description of chaotic dynamics, wave propagation in fractal media, and field theory. For the fractional linear oscillator the physical meaning of the derivative of order $α<2$ is dissipation

Andre Gsponer

The paper addresses some major implications of microelectromechanical systems (MEMS) engineering and nanotechnology for the improvement of existing types of nuclear weapons, and the development of more robust versions of these weapons, as well as for the development of fourth generations nuclear weapons in which nanotechnology will play an essential role.

N. Paar, P. Papakonstantinou, R. Roth, H. Hergert

The fully self-consistent Random Phase Approximation (RPA) is constructed within the Unitary Correlation Operator Method (UCOM), which describes the dominant interaction-induced short-range central and tensor correlations by a unitary transformation. Based on the correlated Argonne V18 interaction, the RPA is employed in studies of multipole response in clos

E. N. E. van Dalen, C. Fuchs, Amand Faessler

Properties of symmetric and asymmetric nuclear matter have been investigated in the relativistic Dirac-Brueckner-Hartree-Fock approach based on projection techniques using the Bonn A potential. The momentum, density, and isospin dependence of the optical potentials and nucleon effective masses are studied. It turns out that the isovector optical potential de

Harald W. Griesshammer

For systems with only short-range forces and shallow 2-body bound states, the typical strength of any 3-body force in all partial-waves, including external currents, is systematically estimated by renormalisation-group arguments in the Effective Field Theory of Point-Like Interactions. The underlying principle and some consequences in particular in Nuclear P

S. De Monte, F. d&#39;Ovidio, E. Mosekilde, H. Chate&#39;

We characterize the macroscopic attractor of infinite populations of noisy maps subjected to global and strong coupling by using an expansion in order parameters. We show that for any noise amplitude there exists a large region of strong coupling where the macroscopic dynamics exhibits low-dimensional chaos embedded in a hierarchically-organized, folded, inf

U. Bruzzo, A. Ricco

We prove a conjecture by F. Ferrari. Let X be the total space of a nonlinear deformation of a rank 2 holomorphic vector bundle on a smooth rational curve, such that X has trivial canonical bundle and has sections. Then the normal bundle to such sections is computed in terms of the rank of the Hessian of a suitably defined superpotential at its critical point

James Currie, Narad Rampersad, Jeffrey Shallit

We characterize the squares occurring in infinite overlap-free binary words and construct various alpha power-free binary words containing infinitely many overlaps.

Nicoletta Cantarini, Victor Kac

We classify open maximal subalgebras of all infinite-dimensional linearly compact simple Lie superalgebras. This is applied to the classification of infinite-dimensional Lie superalgebras of vector fields, acting transitively and primitively in a formal neighborhood of a point of a finite-dimensional supermanifold.

Xavier Caruso

Let O\_K be a complete discrete valuation ring. Denote by K its fractions field and by k its residue field. Assume that k is of characteristic p>0 and perfect. Breuil gives an anti-equivalence between the category of finite flat O\_K-group schemes killed by a power of p and a category of linear algebra objects which is called (Mod/S). The aim of this article

Carlos Cabrelli, Sigrid Heineken, Ursula Molter

Let $ϕ: \R^d \longrightarrow \C$ be a compactly supported function which satisfies a refinement equation of the form $ϕ(x) = \sum_{k\inΛ} c_k ϕ(Ax - k),\quad c_k\in\C$, where $Γ\subset\R^d$ is a lattice, $Λ$ is a finite subset of $Γ$, and $A$ is a dilation matrix. We prove, under the hypothesis of linear independence of the $Γ$-translates of $ϕ$, that there

Margaret A. Readdy

We show how a simplicial complex arising from the WDVV (Witten-Dijkgraaf-Verlinde-Verlinde) equations of string theory is the Whitehouse complex. Using discrete Morse theory, we give an elementary proof that the Whitehouse complex $Δ_n$ is homotopy equivalent to a wedge of $(n-2)!$ spheres of dimension $n-4$. We also verify the Cohen-Macaulay property. Addit

Richard P. Stanley

The length is(w) of the longest increasing subsequence of a permutation w in the symmetric group S_n has been the object of much investigation. We develop comparable results for the length as(w) of the longest alternating subsequence of w, where a sequence a,b,c,d,... is alternating if a>b<c>d<.... For instance, the expected value (mean) of as(w) for w in S_

Sandro Mattarei

We investigate when the sequence of binomial coefficients \binom{k}{i} modulo a prime p, for a fixed positive integer k, satisfies a linear recurrence relation of (positive) degree h in the finite range 0\le i\le k. In particular, we prove that this cannot occur if 2h\le k<p-h. This hypothesis can be weakened to 2h\le k<p if we assume, in addition, that the

Henry Wilton

Elementarily free groups are the finitely generated groups with the same elementary theory as free groups. We prove that elementarily free groups are subgroup separable, answering a question of Zlil Sela.

Javier J. Gutiérrez

We discuss the Bousfield localization $L_E X$ for any spectrum $E$ and any $HR$-module $X$, where $R$ is a ring with unit. Due to the splitting property of $HR$-modules, it is enough to study the localization of Eilenberg-Mac Lane spectra. Using general results about stable $f$-localizations, we give a method to compute the localization of an Eilenberg-Mac L

Christopher J Hillar, Charles R Johnson

The question of whether all words in two real positive definite letters have only positive eigenvalues is addressed and settled (negatively). This question was raised some time ago in connection with a long-standing problem in theoretical physics. A large class of words that do guarantee positive eigenvalues is identified, and considerable evidence is given

S Launois, T H Lenagan

Let q be a nonzero complex number that is not a root of unity. We give a criterion for (0) to be a primitive ideal of the algebra O_q(M_{m,n}) of quantum matrices. Next, we describe all height one primes of O_q(M_{m,n}); these two problems are actually interlinked since it turns out that (0) is a primitive ideal of O_q(M_{m,n}) whenever O_q(M_{m,n}) has only

Corina Baciu

A concrete description of all graded maximal Cohen-Macaulay modules of rank one and two over the affine cone of the simple node (a non-isolated singularity) is given. For this purpose we construct an alghoritm that provides extensions of MCM modules over an arbitrary hypersurface.

Pavol Severa

Motivated by the problem of transverse deformation quantization of foliated manifolds, we describe a quantization of Dirac structures (more precisely, of those that are formal deformations of regular ones) to stacks of algebroids in the sense of Kontsevich.

Nathanael Enriquez

An invariance principle for Azéma martingales is presented as well as a new device to construct solutions of Emery&#39;s structure equations.

Bruce Ikenaga

A group G is almost cyclic if there is an element x in G, such that for all g in G, there is an element y in G and an integer n with ygy^{-1} = x^n (that is, every element is conjugate to some power of x). W. Ziller asked whether there are finitely-presented almost cyclic groups which are not cyclic in connection with work on closed geodesics. V. Guba constr

Yuguang Shi, Luen-Fai Tam

In this paper, we obtain lower bounds for the Brown-York quasilocal mass and the Bartnik quasilocal mass for compact three manifolds with smooth boundaries. As a consequence, we derive sufficient conditions for the existence of horizons for a certain class of compact manifolds with boundary and some asymptotically flat complete manifolds.The method is based

Nedelec Laurence

we obtain the asympotics for the counting function of resonances for a matrix valued schrodinger operator in dimension one.

Houman Owhadi, Lei Zhang

We consider divergence form elliptic operators in dimension $n\geq 2$ with $L^\infty$ coefficients. Although solutions of these operators are only Hölder continuous, we show that they are differentiable ($C^{1,α}$) with respect to harmonic coordinates. It follows that numerical homogenization can be extended to situations where the medium has no ergodicity a

Terence Tao

Szemerédi&#39;s regularity lemma is a basic tool in graph theory, and also plays an important role in additive combinatorics, most notably in proving Szemerédi&#39;s theorem on arithmetic progressions . In this note we revisit this lemma from the perspective of probability theory and information theory instead of graph theory, and observe a variant of this l

Terence Tao

Recent work of Gowers and Nagle, Rödl, Schacht, and Skokan has established a hypergraph removal lemma, which in turn implies some results of Szemerédi and Furstenberg-Katznelson concerning one-dimensional and multi-dimensional arithmetic progressions respectively. In this paper we shall give a self-contained proof of this hypergraph removal lemma. In fact we

Chongsheng Cao, Edriss S. Titi

In this paper we prove the global existence and uniqueness (regularity) of strong solutions to the three-dimensional viscous primitive equations, which model large scale ocean and atmosphere dynamics.

Robert E. Gompf

A topological condition is given, characterizing which closed manifolds in dimensions < 8 (and conjecturally in general) admit symplectic structures. The condition is the existence of a certain fibration-like structure called a hyperpencil. A deformation class of hyperpencils on a manifold X of any even dimension is shown to determine an isotopy class of sym

E. R. Bezerra de Mello

In this paper we present, in a integral form, the Euclidean Green function associated with a massless scalar field in the five-dimensional Kaluza-Klein magnetic monopole superposed to a global monopole, admitting a non-trivial coupling between the field with the geometry. This Green function is expressed as the sum of two contributions: the first one related

M. Caselle, G. Delfino, P. Grinza, O. Jahn

We discuss the two- and three-point correlators in the two-dimensional three-state Potts model in the high-temperature phase of the model. By using the form factor approach and perturbed conformal field theory methods we are able to describe both the large distance and the short distance behaviours of the correlators. We compare our predictions with a set of

M. Casals, P. Kanti, E. Winstanley

The present works complements and expands a previous one, focused on the emission of scalar fields by a (4+n)-dimensional rotating black hole on the brane, by studying the emission of gauge fields on the brane from a similar black hole. A comprehensive analysis of the particle, energy and angular momentum emission rates is undertaken, for arbitrary angular m

Mihail Mintchev, Paul Sorba

The method of bosonization is extended to the case when a dissipationless point-like defect is present in space-time. Introducing the chiral components of a massless scalar field, interacting with the defect in two dimensions, we construct the associated vertex operators. The main features of the corresponding vertex algebra are established. As an applicatio

D. Bashkirov, G. Giachetta, L. Mangiarotti, G. Sardanashvily

We address the problem of extending an original field Lagrangian to ghosts and antifields in order to satisfy the master equation in the framework of the BV quantization of Lagrangian field systems. This extension essentially depends on the degeneracy of an original Lagrangian whose Euler-Lagrange operator generally obeys the Noether identities which need no

Renata Kallosh

We derive algebraic attractor equations describing supersymmetric flux vacua of type IIB string theory in terms of the doublet of the 3-form fluxes, F and H. These equations are similar to the attractor equations for moduli fixed by the charges near the horizon of the supersymmetric black holes.

D. de Florian, A. Kulesza, W. Vogelsang

We study the resummation of large logarithmic QCD corrections for the process pp ->H+ X when the Higgs boson H is produced at high transverse momentum. The corrections arise near the threshold for partonic reaction and originate from soft gluon emission. We perform the all-order resummation at next-to-leading logarithmic accuracy and match the resummed resul

Guy D. Moore

Because the initial shape of the QGP in a heavy ion collision is anisotropic, the momentum distribution becomes anisotropic after a short time. This leads to plasma instabilities, which may help explain how the plasma isotropizes. We explain the physics of instabilities and give the latest results of numerical simulations into their evolution. Nonabelian int

Steven A. Abel, Joerg Jaeckel, Valentin V. Khoze, Andreas Ringwald

We investigate the running gauge couplings of U(N) noncommutative gauge theories with compact extra dimensions. Power law running of the trace-U(1) gauge coupling in the ultraviolet is communicated to the infrared by ultraviolet/infrared mixing, whereas the SU(N) factors run exactly as in the commutative theory. This results in theories where the experimenta

Carlo Ewerz

I review the theoretical and experimental status of the Odderon with emphasis on recent developments.

I. K. Bensafa, F. Iddir, L. Semlala

In this paper, we study the nucleon energy spectrum in the ground-state (with orbital momentum L=0) and the first excited state (L=1). The aim of this study is to find the mass and mixing angles of excited nucleons using a potential model describing QCD. This potential is of the &#34;Coulombian + linear&#34; type and we take into account some relativistic ef

M. I. Levchuk, A. I. L&#39;vov, A. I. Milstein, M. Schumacher

The structure of the $σ$ meson and the diamagnetism of the nucleon are shown to be topics which are closely related to each other. Arguments are found that the $σ$ meson couples to two photons via its non-strange $q\bar{q}$ structure component. This ansatz leads to a quantitative explanation of the $t$-channel component of the difference of electromagnetic p

Thomas D. Cohen

This comment discusses a recent paper by Walliser and Weigel on the quantization of chiral soliton models in the context of exotic baryons. Claims made in that work are misleading due to unfortunate nomenclature. Moreover, attempts in that paper to go beyond the leading order calculations of the phase shifts are ad hoc and never justified. This comment also

R. Frezzotti, G. C. Rossi

In this review we discuss the general features of maximally twisted lattice QCD. In particular, we illustrate how automatic O(a) improvement can be achieved and how it is possible to set up a lattice regularization scheme where the problem of wrong chirality mixing (be it finite or infinite) affecting the computation of the matrix elements of the CP-conservi

Stefan Sint

Using orbifold techniques I construct the Schrodinger functional (SF) for a doublet of Wilson quarks with chirally rotated boundary conditions. This allows to perform checks of universality: for instance, the renormalized SF coupling constant, defined with either boundary conditions, must have a unique continuum limit. Similarly, SF correlation functions in

Z. Fodor, C. Guse, S. Katz, K. Szabo

The grand canonical potential for a static quark-antiquark pair at non-vanishing chemical potential was determined at several temperatures. The dynamical staggered simulations were carried out with 2+1 physical quarks along the Lines of Constant Physiscs (LCP).

Z. Fodor, C. Hoelbling, M. Mechtel, K. Szabo

We perform an investigation of the static quark-quark-potential both in the confined and the deconfined phase. We discuss conceptual and technical problems and present first results of an exploratory numerical investigation.

Falk Bruckmann, Ernst-Michael Ilgenfritz

We compute low-lying eigenmodes of the gauge covariant Laplace operator on the lattice at finite temperature. For classical configurations we show how the lowest mode localizes the monopole constituents inside calorons and that it hops upon changing the boundary conditions. The latter effect we observe for thermalized backgrounds, too, analogously to what is

M. P. Lombardo

We discuss the analytic continuation beyond $μ/T \simeq 1$ in QCD at nonzero T and $μ$ by use of the Pade&#39; approximants. The slope of the critical line obtained in this way increases at large $μ$ with respect to the second order Taylor result.In the hot phase Pade&#39; and Taylor approximants coincide, suggesting a very large, and possibly infinite, radi

Valerio Faraoni, Shahn Nadeau

Conditions for the existence and stability of de Sitter space in modified gravity are derived by considering inhomogeneous perturbations in a gauge-invariant formalism. The stability condition coincides with the corresponding condition for stability with respect to homogeneous perturbations, while this is not the case in scalar-tensor gravity. The stability

J. B. Griffiths, J. Podolsky

The Plebanski-Demianski metric, and those that can be obtained from it by taking coordinate transformations in certain limits, include the complete family of space-times of type D with an aligned electromagnetic field and a possibly non-zero cosmological constant. Starting with a new form of the line element which is better suited both for physical interpret

G. Ruffini

I study the canonical formulation and quantization of some simple parametrized systems, including the non-relativistic parametrized particle and the relativistic parametrized particle. Using Dirac&#39;s formalism I construct for each case the classical reduced phase space and study the dependence on the gauge fixing used. Two separate features of these syste

Sergio Dain

We prove that for any vacuum, maximal, asymptotically flat, axisymmetric initial data for Einstein equations close to extreme Kerr data, the inequality $\sqrt{J} \leq m$ is satisfied, where $m$ and $J$ are the total mass and angular momentum of the data. The proof consists in showing that extreme Kerr is a local minimum of the mass.

Songbai Chen, Jiliang Jing

Using the third-order WKB approximation, we evaluate the quasinormal frequencies of massless scalar field perturbation around the black hole which is surrounded by the static and spherically symmetric quintessence. Our result shows that due to the presence of quintessence, the scalar field damps more rapidly. Moreover, we also note that the quintessential st

David Garfinkle

The detection of gravitational radiation raises some subtle issues having to do with the coordinate invariance of general relativity. This paper explains these issues and their resolution by using an analogy with the Aharonov-Bohm effect of quantum mechanics.

Alexander V. Evako

This paper considers conditions, which allow to preserve important topological and geometric properties in the process of digitization. For this purpose, we introduce a triplet {C,M,D} consisting of a continuous object C, an intermediate model M, which is a collection of subregions whose union is C, a digital model D, which is the intersection graph of M, an

Michele Finelli

Many computer-based authentication schemata are based on pass- words. Logging on a computer, reading email, accessing content on a web server are all examples of applications where the identification of the user is usually accomplished matching the data provided by the user with data known by the application. Such a widespread approach relies on some assumpt

Gerd Bumiller, Liping Lu, Yeqiong Song

In the wide area master-slave PLC (powerline communication) system, the source node cannot reach the destination node without packet relay. Due to the time-variable attenuation in the powerline, the communication distance cannot be defined. Two kind of dynamic repeater algorithms are developed, dynamic source routing and flooding based routing. In this paper

Moritz Hammer, Alexander Knapp, Stephan Merz

We propose a novel algorithm for automata-based LTL model checking that interleaves the construction of the generalized Büchi automaton for the negation of the formula and the emptiness check. Our algorithm first converts the LTL formula into a linear weak alternating automaton; configurations of the alternating automaton correspond to the locations of a gen

Jonghoon Ryu, Oscar Y. Takeshita

An interleaver is a critical component for the channel coding performance of turbo codes. Algebraic constructions are of particular interest because they admit analytical designs and simple, practical hardware implementation. Sun and Takeshita have recently shown that the class of quadratic permutation polynomials over integer rings provides excellent perfor

M. C. Troparevsky, A. Franceschetti

We report semi-empirical pseudopotential calculations of emission spectra of charged excitons and biexcitons in CdSe nanocrystals. We find that the main emission peak of charged multiexcitons - originating from the recombination of an electron in an s-like state with a hole in an s-like state - is blue shifted with respect to the neutral mono exciton. In the

Mathias Rousset, Gabriel Stoltz

We present some applications of an Interacting Particle System (IPS) methodology to the field of Molecular Dynamics. This IPS method allows several simulations of a switched random process to keep closer to equilibrium at each time, thanks to a selection mechanism based on the relative virtual work induced on the system. It is therefore an efficient improvem

Chenggang Zhou, T. C. Schulthess, D. P. Landau

We use Monte Carlo simulations to study ${\rm Ni Fe_2O_4}$ nanoparticles. Finite size and surface effects differentiate them from their bulk counterparts. A continuous version of the Wang-Landau algorithm is used to calculate the joint density of states $g(M_z, E)$ efficiently. From $g(M_z, E)$, we obtain the Bragg-Williams free energy of the particle, and o

H. -J. Grafe, N. J. Curro, M. Hücker, B. Büchner

We report ^{17}O Nuclear Magnetic Resonance (NMR) results in the stripe ordered La_{1.8-x}Eu_{0.2}Sr_{x}CuO_4 system. Below a temperature T_q ~ 80K, the local electric field gradient (EFG) and the absolute intensity of the NMR signal of the planar O site exhibit a dramatic decrease. We interpret these results as microscopic evidence for a spatially inhomogen

David R. Reichman, Patrick Charbonneau

In this set of lecture notes we review the mode-coupling theory of the glass transition from several perspectives. First, we derive mode-coupling equations for the description of density fluctuations from microscopic considerations with the use the Mori-Zwanzig projection operator technique. We also derive schematic mode-coupling equations of a similar form

Aleksandra Vojvodic, Carlo Ruberto, Bengt I. Lundqvist

Extensive density-functional calculations on atomic chemisorption of H, B, C, N, O, F, Al, Si, P, S, and Cl on the polar TiC(111) and TiN(111) yield similar adsorption trends for the two surfaces: (i) pyramid-like adsorption-energy trends along the adatom periods; (ii) strongest adsorption for O, C, N, S, and F; (iii) large adsorption variety; (iv) record-hi

Carlo Ruberto, Bengt I. Lundqvist

Extensive density-functional calculations are performed for chemisorption of atoms in the three first periods (H, B, C, N, O, F, Al, Si, P, S, and Cl) on the polar TiC(111) surface. Calculations are also performed for O on TiC(001), for full O(1x1) monolayer on TiC(111), as well as for bulk TiC and for the clean TiC(111) and (001) surfaces. Detailed results

Simon Trebst, Hartmut Monien, Axel Grzesik, Manfred Sigrist

We study spectral properties of quasiparticles in the Kondo lattice model in one and two dimensions including the coherent quasiparticle dispersions, their spectral weights and the full two-quasiparticle spectrum using a cluster expansion scheme. We investigate the evolution of the quasiparticle band as antiferromagnetic correlations are enhanced towards the

Engin Durgun, Sefa Dag, Salim Ciraci

Gallium displays physical properties which can make it a potential element to produce metallic nanowires and high-conducting interconnects in nanoelectronics. Using first-principles pseudopotential plane method we showed that Ga can form stable metallic linear and zigzag monatomic chain structures. The interaction between individual Ga atom and single-wall c

P. M. Kowalski, S. Mazevet, D. Saumon

We investigate the ionization and the opacity of warm, dense helium under conditions found in the atmospheres of cool white dwarf stars. Our particular interest is in densities up to $\rm 3 g/cm^{3}$ and temperatures from 1000K to 10000K. For these physical conditions various approaches for modeling the ionization equilibrium predict ionization fractions tha

Daniel Greenbaum

It is shown that the diagrammatic cluster expansion technique for equilibrium averages of spin operators may be straightforwardly extended to the calculation of time-dependent correlation functions of spin operators. We use this technique to calculate exactly the first two non-vanishing moments of the spin-spin and energy-energy correlation functions of the

M. Moskalets, M. Buttiker

Using multi-particle distribution functions we calculate the correlations produced by a periodically driven scatterer in a system of noninteracting electrons at zero temperature. The multi-particle correlations due to a quantum exchange effect are expressed in terms of photon-assisted scattering amplitudes. The results we obtain are valid for slow but arbitr

R. J. Radwanski Z. Ropka

We have shown the existence of localized crystal-field states in conducting magnetic materials coexisting with conduction electrons in CeAl3, UPd2Al3 and YbRh2Si2. We point out that the magnetism is strongly correlated with the very detailed local atomic-scale crystal structure.

Z. Ropka R. J. Radwanski

We have calculated the electronic structure of V2O3 associated with the V3+ ions taking into account strong on-site electron correlations and the spin-orbit coupling. Closely lying 9 states of the subterm 3T1g are a physical reason for exotic phenomena of V2O3. Electronic structure and magnetism of V3+ ions in the octahedral surroundings are strongly suscept

Jun He, Yingli Qu, Heping Li, Jun Mi

We report a systematic investigation of both three-photon absorption (3PA)spectra and wavelength dispersions of Kerr-type nonlinear refraction in wide-gap semiconductors. The Z-scan measurements are recorded for both ZnO and ZnS with femtosecond laser pulses. While the wavelength dispersions of the Kerr nonlinearity are in agreement with a two-band model, th

L. Craco, M. S. Laad, E. Müller-Hartmann

Motivated by recent structural data questioning the adequacy of the charge order (CO)/disorder picture for the Verwey transition (at T=T_V) in magnetite, we re-investigate this issue within a new theoretical picture. Using the state-of-the-art LDA+DMFT method, we show that the non-trivial interplay between the B-site octahedral distortions and strong, multi-

J. K. Bhattacharya, Dipanjan Chakraborty, Himadri Shekar Samanta

We discuss Brownian Motion from a more elementary viewpoint presented by Einstein in 1908. Later developments and applications are briefly reviewed.

M. Crisan, I. Tifrea, D Bodea, I. Grosu

We use the Renormalization Group method to study the magnetic field influence on the Bose-Einstein condensation of interacting dilute magnons in three dimensional spin systems. We first considered a model with SU(2) symmetry (universality class $z=1$) and we obtain for the critical magnetic field a power law dependence on the critical temperature, $[H_c(T)-H

V. N. Krivoruchko, V. Yu. Tarenkov, A. I. D&#39;yachenko, V. N. Varyukhin

The Andreev reflection (AR) spectroscopy has been used to probe mutual influence of superconducting pairing and ferromagnetic correlations in contacts of low-temperature superconductor (S), Pb, and half-metallic ferromagnetic, La0.65Ca0.35MnO3(LCMO). Two different AR spectra have been observed. In the contacts without proximity effect, the AR spectra reveal

N. A. Buznikov, A. S. Antonov, A. B. Granovsky, C. G. Kim

A method for calculation of the magnetoimpedance in composite wires having an insulator layer between non-magnetic core and soft magnetic shell is described. It is assumed that the magnetic shell has a helical anisotropy and the driving current flows through the core only. The distribution of eddy currents and expressions for the impedance are found by means

Nicolas Douarche, Simona Cocco

This paper focuses on the probability that a portion of DNA closes on itself through thermal fluctuations. We investigate the dependence of this probability upon the size r of a protein bridge and/or the presence of a kink at half DNA length. The DNA is modeled by the Worm-Like Chain model, and the probability of loop formation is calculated in two ways: exa

L. Chevillard, N. Mazellier, C. Poulain, Y. Gagne

We perform a statistical analysis of experimental fully developed turbulence longitudinal velocity data in the Fourier space. We address the controversial issue of statistical intermittency of spatial Fourier modes by acting on the finite spectral resolution. We derive a link between velocity structure functions and the flatness of Fourier modes thanks to ca

Jaebeom Yoo, Shailesh Chandrasekharan, Ribhu K. Kaul, Denis Ullmo

We show that there is no fermion sign problem in the Hirsch and Fye algorithm for the single-impurity Anderson model. Beyond the particle-hole symmetric case for which a simple proof exists, this has been known only empirically. Here we prove the nonexistence of a sign problem for the general case by showing that each spin trace for a given Ising configurati

Yan Li, Slava V. Rotkin, Umberto Ravaioli

The electronic band structure of armchair carbon nanotubes may be considerably modified by potentials with angular dependence. Different angular modes V_q ~ cos(q*theta) have been studied within a tight-binding scheme. Using symmetry arguments, we demonstrate a bandgap opening in these metallic nanotubes when certain selection rules are satisfied for both po

Asaf Pe&#39;er, Ralph A. M. J. Wijers

Explosions of massive stars are believed to be the source of a significant fraction of gamma-ray bursts (GRBs). If this is indeed the case, then the explosion blast wave propagates into a complex density structure, composed of a stellar wind bounded by two shock waves - a wind reverse shock and a forward shock. As the explosion blast wave reaches R_0, the ra

A. Alonso-Herrero, P. G. Perez-Gonzalez, D. M. Alexander, G. H. Rieke

We investigate the nature of a sample of 92 Spitzer/MIPS 24 micron selected galaxies in the CDFS, showing power law-like emission in the Spitzer/IRAC 3.6-8 micron bands. The main goal is to determine whether the galaxies not detected in X-rays (47% of the sample) are part of the hypothetical population of obscured AGN not detected even in deep X-ray surveys.

Rosalba Perna, Philip J. Armitage, Bing Zhang

Early-time X-ray observations of GRBs with the Swift satellite have revealed a more complicated phenomenology than was known before. In particular, the presence of flaring activity on a wide range of time scales probably requires late-time energy production within the GRB engine. Since the flaring activity is observed in both long and short GRBs, its origin

Dana S. Balser, W. M. Goss, T. M. Bania, Robert T. Rood

We used the VLA to search for 3He+ emission from two Galactic planetary nebulae (PNe): NGC6572 and J320}. Standard stellar models predict that the 3He/H abundance ratios for PNe should be 1-2 orders of magnitude higher than the primordial value (3He/H ~ 1e-5 by number) determined from Galactic HII region abundances and confirmed by WMAP cosmic microwave back

L. A. Nolan, M. O. Harva, A Kaban, S. Raychaudhury

We present the results of a novel application of Bayesian modelling techniques, which, although purely data driven, have a physically interpretable result, and will be useful as an efficient data mining tool. We base our studies on the UV-to-optical spectra (observed and synthetic) of early-type galaxies. A probabilistic latent variable architecture is formu

Andrew W. Stephens, Marcio Catelan, Roxana P. Contreras

Globular clusters have long been known for presenting (at times) significant deviations from spherical symmetry. While rotation has been the main proposed explanation, other complicating factors such as their constant interaction with the strong gravitational potential of their host galaxy have made it difficult for a consensus to be reached. To address this

L. Nava, G. Ghisellini, G. Ghirlanda, F. Tavecchio

Recently, Liang & Zhang (2005) found a tight correlation involving only observable quantities, namely the isotropic emitted energy $E_{γ,iso}$, the energy of the peak of the prompt spectrum $E^\prime_{p}$, and the jet break time $t^\prime_{j}$. This phenomenological correlation can have a first explanation in the framework of jetted fireballs, whose semiaper

E. Berger, B. E. Penprase, S. B. Cenko, S. R. Kulkarni

We present the discovery of the optical afterglow of GRB 050505 and an optical absorption spectrum obtained with the Keck I 10-m telescope. The spectrum exhibits three redshifted absorption systems with the highest, at z=4.2748, arising in the GRB host galaxy. The host absorption system is marked by a damped Ly-alpha (DLA) feature with a neutral hydrogen col

Orsola De Marco, Michael M. Shara, D. Zurek, John A. Ouellette

We present a spectroscopic analysis of HST/STIS and FOS low- and intermediate-resolution spectroscopy of 55 stars (turn-off stars, horizontal branch stars and blue stragglers) in four globular clusters (47 Tucanae, M3, NGC6752, and NGC6397). Stars were analyzed with non-Local Thermodynamic Equilibrium model atmospheres, and values for their effective tempera