March 2006 arXiv papers — page 37

Peter Bose, Juergen Henk, Ingrid Mertig

Spin-dependent ballistic transport through a tunnel barrier is treated within the one-dimensional nearly-free-electron model. The comparison with free electrons reveals significant effects of band gaps, in particular in the bias dependence. The results are qualitatively explained by the number of incident and transmitted states in the leads. With an extensio

T. Jeong

The electronic band structure of CeAgSb$_{2}$ has been calculated using the self-consistent full potential nonorthogonal local orbital minimum basis scheme based on the density functional theory. We investigated the electronic structure with the spin-orbit interaction and on-site Coulomb potential for the Ce-derived 4f orbitals to obtain the correctly ground

L. I. Plimak, C. Weiß, R. Walser, W. P. Schleich

We analyse and numerically simulate the full many-body quantum dynamics of a spin-1 condensate in the single spatial mode approximation. Initially, the condensate is in a ``ferromagnetic'' state with all spins aligned along the $y$ axis and the magnetic field pointing along the z axis. In the course of evolution the spinor condensate undergoes a char

T. Jeong

The electronic structure of HfZn$_{2}$ has been studied based on the density functional theory within the local-density approximation. The calculation indicates that HfZn$_{2}$ shows ferromagnetic instability. Large enhancement of the static susceptibility over its non-interacting value is found due to a peak in the density of states at the Fermi level.

T. Jeong

The electronic structure of Y$_{4}$Co$_{3}$ has been studied based on the density functional theory within the local-density approximation. The calculation indicates that Y$_{4}$Co$_{3}$ is very close to ferromagnetic instability. The Fermi surfaces are composed mainly of 3d electrons of Co and 4d electrons of Y.

E. Abad, J. J. Kozak

The efficiency of an encounter-controlled two-channel reaction between two independently-mobile reactants on a lattice is characterized by the mean number $\rt$ of steps to reaction. The two reactants are distinguished by their mass with the "light" walker performing a jump to a nearest-neighbor site in each time step, while the "heavy" walke

N. Barberan, M. Lewenstein, K. Osterloh, D. Dagnino

The characterization of small samples of cold bosonic atoms in rotating microtraps has recently attracted increasing interest due to the possibility to deal with a few number of particles per site in optical lattices. We analyze the evolution of ground state structures as the rotational frequency $Ω$ increases. Various kinds of ordered structures are observe

Simon Laird, Henrik Jeldtoft Jensen

Using a steady state process of node duplication and deletion we produce networks with 1/k scale-free degree distributions in the limit of vanishing connectance. This occurs even though there is no growth involved and inherent preferential attachment is counterbalanced by preferential detachment. The mean field evolution is considered and the 1/k law is veri

Holger Frahm, Guillaume Palacios

We consider an integrable model describing an Anderson-like impurity coupled to an open $t$--$J$ chain. Both the hybridization (i.e. its coupling to bulk chain) and the local spectrum can be controlled without breaking the integrability of the model. As the hybridization is varied, holon and spinon bound states appear in the many body ground state. Based on

V. A. Brazhnyi, V. V. Konotop, L. P. Pitaevskii

We present a theory of dark soliton dynamics in trapped quasi-one-dimensional Bose-Einstein condensates, which is based on the local density approximation. The approach is applicable for arbitrary polynomial nonlinearities of the mean-field equation governing the system as well as to arbitrary polynomial traps. In particular, we derive a general formula for

I. Kuryliszyn-Kudelska, W. Dobrowolski, M. Arciszewska, V. Domukhovski

We present the study of magnetic and transport properties of Pb(1-x-y-z)Mn(x)Sn(y)Eu(z)Te. AC magnetic susceptibility measurements as well as transport characterization were performed. The obtained results indicate that the presence of two types of magnetic ions influences magnetic properties of investigated IV-VI semimagnetic semiconductor. A qualitative an

Masanori Kohno, Xiangang Wan, Xiao Hu

Magnetic and electronic properties of the recently-discovered material Sr8CaRe3Cu4O24 were investigated by means of a quantum Monte Carlo simulation, the Green function method and the LSDA+U (local spin-density approximation plus the Hubbard-U term) method. The LSDA+U calculation shows that the ground state is an insulator with magnetic moment M=1.01\muB/f.u

Masanori Kohno, Xiao Hu

Significant decrease of spontaneous magnetization in frustrated one-dimensional ferro- and ferrimagnets due to non-magnetic impurities is predicted. Using the density-matrix renormalization group method and the exact diagonalization method, we confirm that the total spin can vanish due to a single impurity in finite chains. Introducing the picture of magneti

William Kung, A. W. C. Lau

We present an exact field-theoretic formulation for a fluctuating, generally asymmetric, salt density in the presence of a charged plate. The non-linear Poisson-Boltzmann equation is obtained as the saddle-point of our field theory action. Focusing on the case of symmetric salt, we systematically compute first-order corrections arising from electrolytes fluc

Violeta Iancu, Aparna Deshpande, Saw -Wai Hla

Two conformations of isolated single TBrPP-Co molecules on a Cu(111) surface are switched by applying +2.2 V voltage pulses from a scanning tunneling microscope tip at 4.6 K. The TBrPP-Co has a spin-active cobalt atom caged at its center and the interaction between the spin of this cobalt atom and free electrons from the Cu(111) substrate can cause a Kondo r

P. W. Brouwer, A. Furusaki, C. Mudry, S. Ryu

The Anderson metal-insulator transition is a continuous phase transition driven by disorder. It remains a challenging problem to theoretically determine universal critical properties at the transition. The Anderson transition in a model with a discrete sublattice or particle-hole symmetry belongs to one of seven universality classes which are different from

Huaiming Guo, Shiping Feng

Within the t-t'-J model, the asymmetry of the electron spectrum and quasiparticle dispersion in hole-doped and electron-doped cuprates is discussed. It is shown that the quasiparticle dispersions of both hole-doped and electron-doped cuprates exhibit the flat band around the (π,0) point below the Fermi energy. The lowest energy states are located at the

Alexandru Macridin, Mark Jarrell, Thomas Maier, P. R. C. Kent

Using the dynamical cluster approximation and quantum monte carlo we calculate the single-particle spectra of the Hubbard model with next-nearest neighbor hopping $t'$. In the underdoped region, we find that the pseudogap along the zone diagonal in the electron doped systems is due to long range antiferromagnetic correlations. The physics in the proximit

Viljo Petaja, Matti Sarjala, Mikko Alava, Heiko Rieger

We investigate by exact optimization method properties of two- and three-dimensional systems of elastic lines in presence of splayed columnar disorder. The ground state of many lines is separable both in 2d and 3d leading to a random walk -like roughening in 2d and ballistic behavior in 3d. Furthermore, we find that in the case of pure splayed columnar disor

R. G. Vishwakarma

A recent paper by Ahluwalia-Khalilova (astro-ph/0601489) is examined where he claims that the standard FRW cosmology with a $Λ$ predicts existence of dark matter without invoking the data on galactic rotation curves and gravitational lensing. However, we find that his claims are not correct. He has already assumed (without realizing) in the very outset what

T. Belloni, P. Soleri, P. Casella, M. Mendez

We report the results of a systematic timing analysis of RXTE observations of GRS 1915+105 when the source was in its variability class theta, characterized by alternating soft and hard states on a time scale of a few hundred seconds. The aim was to examine the high-frequency part of the power spectrum in order to confirm the hecto-Hertz Quasi-Periodic Oscil

Joseph Silk

The challenge of dark matter may be addressed in two ways; by studying the confrontation of structure formation with observation and by direct and indirect searches. In this review, I will focus on those aspects of dark matter that are relevant for understanding galaxy formation, and describe the outlook for detecting the most elusive component, non-baryonic

Herve Dole, Guilaine Lagache, Jean-Loup Puget, Karina I. Caputi

Aims. We quantify the contributions of 24um galaxies to the Far-Infrared (FIR) Background at 70 and 160um. We provide new estimates of the Cosmic Infrared Background (CIB), and compare it with the Cosmic Optical Background (COB). Methods. Using Spitzer data at 24, 70 and 160um in three deep fields, we stacked more than 19000 MIPS 24um sources with S24>60uJy

D. Nutter, D. Ward-Thompson, P. Andre

We present submillimetre data for the L1689 cloud in the rho-Ophiuchi molecular cloud complex. We detect a number of starless and prestellar cores and protostellar envelopes. We also detect a number of filaments for the first time in the submillimetre continuum that are parallel both to each other, and to filaments observed in the neighbouring L1688 cloud. T

D. A. Neufeld, P. Schilke, K. M. Menten, M. G. Wolfire

We discuss the first astronomical detection of the CF+ (fluoromethylidynium) ion, obtained by observations of the J=1-0 (102.6 GHz), J=2-1 (205.2 GHz) and J=3-2 (307.7 GHz) rotational transitions toward the Orion Bar region. Our search for CF+, carried out using the IRAM 30m and APEX 12m telescopes, was motivated by recent theoretical models that predict CF+

Ilian T. Iliev, Benedetta Ciardi, Marcelo A. Alvarez, Antonella Maselli

Radiative transfer simulations are now at the forefront of numerical astrophysics. They are becoming crucial for an increasing number of astrophysical and cosmological problems; at the same time their computational cost has come to the reach of currently available computational power. Further progress is retarded by the considerable number of different algor

M. F. Bietenholz

New 1.4 GHz VLA observations of the pulsar-powered supernova remnant 3C 58 have resulted in the highest-quality radio images of this object to date. The images show filamentary structure over the body of the nebula. The present observations were combined with earlier ones from 1984 and 1991 to investigate the variability of the radio emission on a variety of

J. C. B. Papaloizou, R. P. Nelson, W. Kley, F. S. Masset

The discovery of close orbiting extrasolar giant planets led to extensive studies of disk planet interactions and the forms of migration that can result as a means of accounting for their location. Early work established the type I and type II migration regimes for low mass embedded planets and high mass gap forming planets respectively. While providing an a

Joel C. Allred, Suzanne L. Hawley, William P. Abbett, Mats Carlsson

We report on radiative hydrodynamic simulations of M dwarf stellar flares and compare the model predictions to observations of several flares. The flares were simulated by calculating the hydrodynamic response of a model M dwarf atmosphere to a beam of non-thermal electrons. Radiative backwarming through numerous soft X-ray, extreme ultraviolet, and ultravio

B. Aschenbach

I report the discovery of a new effect of General Relativity which is important to understand very rapidly rotating (Kerr) black holes. The orbital velocity of a test particle is no longer a monotonic function of the orbit radius when the spin of the black hole is >0.9953, but displays a local minimum-maximum structure for radii smaller than 1.8 gravitationa

W. Boschin, M. Girardi, M. Spolaor, R. Barrena

We present a detailed dynamical analysis of the rich galaxy cluster A2744, containing a powerful diffuse radio halo.Our analysis is based on redshift data for 102 galaxies, part of them recovered from unexplored spectra in the ESO archive. We combine galaxy velocity and position information to select the cluster members and determine global dynamical propert

M. Mouhcine

We present an analysis of the metallicity distribution functions of fields projected along the minor axis for a sample of inclined spiral galaxies in order to search for evidence of the presence of multiple stellar populations. In all cases, the stellar populations appear to have asymmetric metallicity distributions with very high confidence levels. The mean

Donatella Romano, Monica Tosi, Cristina Chiappini, Francesca Matteucci

(Abridged) Estimates of the interstellar deuterium abundance span a wide range of values. Here we study the evolution of deuterium in the framework of successful models for the chemical evolution of the Milky Way able to reproduce the majority of the observational constraints for the solar neighbourhood and for the Galactic disc. We show that, in the framewo

Danica Kröger, Gerhard Hensler, Tim Freyer

It is clear from stellar evolution and from observations of WR stars that massive stars are releasing metal-enriched gas through their stellar winds in the Wolf-Rayet phase. Although HII region spectra serve as diagnostics to determine the present-day chemical composition of the interstellar medium, it is far from being understood to what extent the HII gas

John J. Eldridge, Jorick S. Vink

Aims: Recent theoretical predictions for the winds of Wolf-Rayet stars indicate that their mass-loss rates scale with the initial stellar metallicity in the local Universe.We aim to investigate how this predicted dependence affects the models of Wolf-Rayet stars and their progeny in different chemical environments. Methods: We compute models of stellar struc

F. Favata, R. Bonito, G. Micela, M. Fridlund

We have performed, in October 2005, a deep Chandra X-ray observation of HH 154. Comparison with the previous (2001) Chandra observation allows to detect proper motion down to the level predicted by models of X-ray emitting shocks in the jet. The 2005 Chandra observation of HH 154 shows unexpected morphological changes of the X-ray emission in comparison with

D. Koester, D. Wilken

We calculated diffusion timescales for Ca, Mg, Fe in hydrogen atmosphere white dwarfs with temperatures between 5000 and 25000 K. With these timescales we determined accretion rates for a sample of 38 DAZ white dwarfs from the recent studies of Zuckerman et al. (2003) and Koester et al. (2005). Assuming that the accretion rates can be calculated with the Bon

Masaomi Tanaka, Paolo A. Mazzali, Keiichi Maeda, Ken'ichi Nomoto

Spectral synthesis in 3-dimensional (3D) space for the earliest spectra of Type Ia supernovae (SNe Ia) is presented. In particular, the high velocity absorption features that are commonly seen at the earliest epochs ($\sim 10$ days before maximum light) are investigated by means of a 3D Monte Carlo spectral synthesis code. The increasing number of early spec

Craig S. Rudick, J. Christopher Mihos, Cameron McBride

Using N-body simulations, we have modeled the production and evolution of low surface brightness, diffuse intra-cluster light (ICL) in galaxy clusters. By creating simulated observations of the clusters we have measured the evolution of the ICL luminosity throughout the dynamical history of the clusters. We find that ICL production tends to occur in short, d

Sean M. Moran, Richard S. Ellis, Tommaso Treu, Samir Salim

We present new results from deep GALEX UV imaging of the cluster Cl 0024+17 at z~0.4. Rest-frame far UV emission is detected from a large fraction of so-called ``passive spiral galaxies'' -a significant population which exhibits spiral morphology with little or no spectroscopic evidence for ongoing star formation. This population is thought to repres

A. Monfardini, S. Kobayashi, C. Guidorzi, D. Carter

The 2-m robotic Liverpool Telescope (LT) reacted promptly to the high-redshift (z=4.048) gamma-ray burst GRB 060206. The afterglow was identified automatically and multicolor r'i'z' imaging was triggered without human intervention. Combining our data with those obtained from later follow-ups provides a well-sampled optical light-curve from 5 minu

Richard Durisen, Alan Boss, Lucio Mayer, Andy Nelson

Protoplanetary gas disks are likely to experience gravitational instabilites (GI's) during some phase of their evolution. Density perturbations in an unstable disk grow on a dynamic time scale into spiral arms that produce efficient outward transfer of angular momentum and inward transfer of mass through gravitational torques. In a cool disk with rapid e

S. A. Khan, D. V. Shulyak

The technique of model atmosphere calculation for magnetic Ap and Bp stars with polarized radiative transfer and magnetic line blanketing is presented. A grid of model atmospheres of A and B stars are computed. These calculations are based on direct treatment of the opacities due to the bound-bound transitions that ensures an accurate and detailed descriptio

Tyrrell B. McAllister

Given a partition l and a composition b, the stretched Kostka coefficient K_{l, b}(n) is the map sending each positive integer n to the Kostka coefficient indexed by nl and nb. Kirillov and Reshetikhin (1986) have shown that stretched Kostka coefficients are polynomial functions of n. King, Tollu, and Toumazet have conjectured that these polynomials always h

Alfredo Raya, Jose Edgar Madriz Aguilar, Mauricio Bellini

We propose a novel formalism for inflation from a 5D vacuum state which could explain both, seeds of matter and magnetic fields in the early universe.

W. A. Al-Saidi, Shiwei Zhang, Henry Krakauer

We extend the recently introduced phaseless auxiliary-field quantum Monte Carlo (QMC) approach to any single-particle basis, and apply it to molecular systems with Gaussian basis sets. QMC methods in general scale favorably with system size, as a low power. A QMC approach with auxiliary fields in principle allows an exact solution of the Schrodinger equation

M. J. Calderon, S. Das Sarma

We analyze the origin of ferromagnetism as a result of carrier mediation in diluted magnetic oxide semiconductors in the light of the experimental evidence reported in the literature. We propose that a combination of percolation of magnetic polarons at lower temperature and Ruderman-Kittel-Kasuya-Yosida ferromagnetism at higher temperature may be the reason

Philip Tillman, George Sparling

In this paper we construct the set of quantum mechanical observables in the Fedosov *-formalism (a coordinate invariant way to do quantum mechanics on any manifold M) of a single free particle that lives on a constant curvature manifold with metric signature (p,q). This was done for most but not all constant curvature manifolds. We show that the algebra of a

Eaman Eftekhary

We establish surgery formulas for filtration of the Heegaard Floer homology associated with p/q surgery on a null-homologous knot K in a three-manifold Y, induced by K_{p/q}. Here K_{p/q} is the core of the attached solid torus (which produces the surgery). This would generalize a result of Ozsvath and Szabo. We will re-prove that surgery on non-trivial knot

Deborah Freedman Woods, Margaret J. Geller, Elizabeth J. Barton

We study star formation in a sample of 345 galaxies in 167 pairs and compact groups drawn from the original CfA2 Redshift Survey and from a follow-up search for companions. We construct our sample with attention to including pairs with luminosity contrast |Δm_R| >= 2. These 57 galaxies with |Δm_R| >= 2 provide a set of nearby representative cases of minor in

Sebastian de Haro, Sanjaye Ramgoolam, Alessandro Torrielli

We derive the q-deformation of the chiral Gross-Taylor holomorphic string large N expansion of two dimensional SU(N) Yang-Mills theory. Delta functions on symmetric group algebras are replaced by the corresponding objects (canonical trace functions) for Hecke algebras. The role of the Schur-Weyl duality between unitary groups and symmetric groups is now play

Michael C. Cooper, Jeffrey A. Newman, Darren J. Croton, Benjamin J. Weiner

We study the mean environment of galaxies in the DEEP2 Galaxy Redshift Survey as a function of rest-frame color, luminosity, and [OII] equivalent width. The local galaxy overdensity for >14,000 galaxies at 0.75 < z < 1.35 is estimated using the projected 3rd-nearest-neighbor surface density. Of the galaxy properties studied, mean environment is found to depe

Yuri V. Kovchegov, Kirill Tuchin

We calculate production of quark-antiquark pairs in high energy proton-nucleus collisions both in the quasi-classical approximation of McLerran-Venugopalan model and including quantum small-$x$ evolution. The resulting production cross section is explicitly expressed in terms of Glauber-Mueller multiple rescatterings in the classical case and in terms of dip

Viktor T Toth, Slava G Turyshev

The Pioneer 10 and 11 spacecraft yielded very accurate navigation that was limited only by a small, anomalous frequency drift of their carrier signals received by the NASA Deep Space Network (DSN). This discrepancy, evident in the data for both spacecraft, was interpreted as an approximately constant acceleration and has become known as the Pioneer anomaly.

Mohsen Nejad-Asghar, Jamshid Ghanbari

A systematic study of the linear thermal instability of a self-gravitating magnetic molecular cloud is carried out for the case when the unperturbed background is subject to local expansion or contraction. We consider the ambipolar diffusion, or ion-neutral friction on the perturbed states. In this way, we obtain a non-dimensional characteristic equation tha

Phung Ho Hai, Martin Lorenz

We give a new proof of the quantum version of MacMahon&#39;s Master Theorem due to Garoufalidis, Le and Zeilberger (one-parameter case) and to Konvalinka and Pak (multiparameter case) by deriving it from known facts about Koszul algebras.

V. N. Yershov

The properties of cyclic structures (toroidal oscillators) based on classical tripolar (colour) fields are discussed, in particular, of a cyclic structure formed of three colour-singlets spinning around a ring-closed axis. It is shown that the helicity and handedness of this structure can be related to the quantum properties of the electron. The symmetry of

Matthew Britton

The effects of anisoplanatism on the adaptive optics point spread function are investigated. A model is derived that combines observations of the guide star with an analytic formulation of anisoplanatism to generate predictions for the adaptive optics point spread function at arbitrary locations within the field of view. The analytic formulation captures the

Daryl Cooper, Genevieve S Walsh

We apply representation theory to study the homology of equivariant Dehn-fillings of a given finite, regular cover of a compact 3-manifold with boundary a torus. This yields a polynomial which gives the rank of the part of the homology carried by the solid tori used for Dehn-filling. The polynomial is a symmetrized form of the group determinant studied by Fr

Martin Land

It is by now well-known that a Lorentz force law and the homogeneous Maxwell equations can be derived from commutation relations among Euclidean coordinates and velocities, without explicit reference to momentum, action or variational principle. This result was extended to the relativistic case and shown to correspond to a Stueckelberg-type quantum theory, i

Alexei Vazquez

Infectious diseases and computer malwares spread among humans and computers through the network of contacts among them. These networks are characterized by wide connectivity fluctuations, connectivity correlations and the small-world property. In a previous work [A. Vazquez, Phys. Rev. Lett. 96, 038702 (2006)] I have shown that the connectivity fluctuations

F. M. Paiva, A. F. F. Teixeira

The relativistic time is different from the Newtonian one. We revisit some of these differences in Doppler effect, twin paradox, rotation, rigid rod, and constant proper acceleration. ------- La relativeca tempo estas malsama ol la Newtona. Ni revidos iujn el tiuj malsamoj en Dopplera efiko, gxemel-paradokso, rotacio, rigida stango, kaj konstanta propra akce

H. Grosse, H. Steinacker

We study the quantization of the noncommutative selfdual ϕ^3 model in 4 dimensions, by mapping it to a Kontsevich model. The model is shown to be renormalizable, provided one additional counterterm is included compared to the 2-dimensional case which can be interpreted as divergent shift of the field ϕ. The known results for the Kontsevich model allow to obt

Wakako Nakai, Tomoki Nakanishi

We study the Jacobi-Trudi-type determinant which is conjectured to be the q-character of a certain, in many cases irreducible, finite-dimensional representation of the quantum affine algebra of type D_n. Unlike the A_n and B_n cases, a simple application of the Gessel-Viennot path method does not yield a positive sum expression of the determinant over a set

Michael Falk, Sergey Yuzvinsky

We show that a line arrangement in the complex projective plane supports a nontrivial resonance variety if and only if it is the underlying arrangement of a &#34;multinet,&#34; a multi-arrangement with a partition into three or more equinumerous classes which have equal multiplicities at each inter-class intersection point, and satisfy a connectivity conditi

E. M. Hankiewicz, G. Vignale, M. Flatte

A self-consistent treatment of the spin-Hall effect requires consideration of the spin-orbit coupling and electron-impurity scattering on equal footing. This is done here for the experimentally relevant case of a [110] GaAs quantum well [Sih {\it et al.}, Nature Physics 1, 31 (2005)]. Working within the framework of the exact linear response formalism we cal

Anders W. Sandvik

The S=1/2 Heisenberg model is considered on bilayer and single-layer square lattices with couplings J1, J2, and with each spin belonging to one J2-coupled dimer. A transition from a Neel to disordered ground state occurs at a critical value of g=J2/J1. The systems are here studied at their dimer-dilution percolation points p*. The multi-critical point (g*,p*

Stijn Heymans, Davy Van Nieuwenborgh, Dirk Vermeir

Open answer set programming (OASP) is an extension of answer set programming where one may ground a program with an arbitrary superset of the program&#39;s constants. We define a fixed point logic (FPL) extension of Clark&#39;s completion such that open answer sets correspond to models of FPL formulas and identify a syntactic subclass of programs, called (lo

M. Simon, C. Bender, L. Prato

We report the results of high spectral and angular resolution infrared observations of the multiple system GL 569 A and B that were intended to measure the dynamical masses of the brown dwarf binary believed to comprise GL 569 B. Our analysis did not yield this result but, instead, revealed two surprises. First, at age ~100 Myr, the system is younger than ha

Bing He, János A. Bergou

We present a general scheme to realize the POVMs for the unambiguous discrimination of quantum states. For any set of pure states it enables us to set up a feasible linear optical circuit to perform their optimal discrimination, if they are prepared as single-photon states. An example of unknown states discrimination is discussed as the illustration of the g

Bruce A. Campbell, David W. Maybury

For the D=5 Majorana neutrino mass operator to have a see-saw ultraviolet completion that is viable up to the Planck scale, the see-saw scale is bounded above due to triviality limits on the see-saw couplings. For supersymmetric see-saw models, with realistic neutrino mass textures, we compare constraints on the see-saw scale from triviality bounds, with tho

Zheng Ze Ma

Quantum field theories on noncommutative spacetime have many different properties from those on commutative spacetime. In this paper, we study the microcausality of free scalar field on noncommutative spacetime. We expand the scalar field in the form of usual Lorentz invariant measure in noncommutative spacetime. Then we calculate the expectation values of t

A. V. Efremov, K. Goeke, P. Schweitzer

The Collins fragmentation function is extracted from HERMES data on azimuthal single spin asymmetries in semi-inclusive deeply inelastic scattering, and BELLE data on azimuthal asymmetries in electron positron annihilations. A Gaussian model is assumed for the distribution of transverse parton momenta and predictions are used from the chiral quark-soliton mo

Vyacheslav Shatokhin, Cord A. Müller, Andreas Buchleitner

We give a detailed derivation of the master equation description of the coherent backscattering of laser light by cold atoms. In particular, our formalism accounts for the nonperturbative nonlinear response of the atoms when the injected intensity saturates the atomic transition. Explicit expressions are given for total and elastic backscattering intensities

Jernej Mravlje, Anton Ramsak, Tomaz Rejec

We investigate a symmetrical double quantum dot system serially attached to the leads. The emphasis is on the numerical analysis of finite inter-dot tunneling in the presence of inter-dot repulsive capacitive coupling. The results reveal the competition between extended Kondo phases and local singlet phases in spin and charge degrees of freedom. The correspo

Woong-Seob Jeong, Chris P. Pearson, Hyung Mok Lee, Soojong Pak

We present a comprehensive analysis for the determination of the confusion levels for the current and the next generation of far-infrared surveys assuming three different cosmological evolutionary scenarios. We include an extensive model for diffuse emission from infrared cirrus in order to derive absolute sensitivity levels taking into account the source co

Oyvind Gron, Oystein Elgaroy

The interpretation of the expanding universe as an expansion of space has recently been challenged. From the geodesic equation in Friedmann universe models and the empty Milne model, we argue that a Newtonian or special relativistic analysis is not applicable on large scales, and the general relativistic interpretation in terms of expanding space has the adv

O. Zagordi, A. Michelangeli

Appearance of energy bands and gaps in the dispersion relations of a periodic potential is a standard feature of Quantum Mechanics. We investigate the class of one-dimensional periodic potentials for which all gaps vanish at the center of the Brillouin zone. We characterize them through a necessary and sufficient condition. Potentials of the form we focus on

Giovanni Landi, Walter van Suijlekom

We present an introduction to the use of noncommutative geometry for gauge theories with emphasis on a construction of instantons for a class of four dimensional toric noncommutative manifolds. These instantons are solutions of self-duality equations and are critical points of an action functional. We explain the crucial role of twisted symmetries as well as

Vladimir P. Gerdt, Yuri A. Blinkov

We consider three modifications of our involutive algorithm for computing Janet bases. These modifications are related to degree compatible monomial orders and specify selection strategies for non-multiplicative prolongations. By using the standard data base of polynomial benchmarks for \Gr bases software we compare the modifications and confront them with M

Xia Chen

We study the upper tail behaviors of the local times of the additive stable processes. Let $X_1(t),...,X_p(t)$ be independent, d-dimensional symmetric stable processes with stable index $0<α\le 2$ and consider the additive stable process $\bar{X}(t_1,...,t_p)=X_1(t_1)+... +X_p(t_p)$. Under the condition $d<αp$, we obtain a precise form of the large deviation

Ali Ahanj, Pramod Joag, Sibasish Ghosh

We give a classical protocol to exactly simulate quantum correlations implied by a spin-$s$ singlet state for the infinite sequence of spins satisfying $(2s + 1) = 2^{n}$, in the worst-case scenario, where $n$ is a positive integer. The class of measurements we consider here are only those corresponding to spin observables. The required amount of communicati

Andrea Jimenez-Dalmaroni

We introduce a model for directed percolation with a long-range temporal diffusion, while the spatial diffusion is kept short ranged. In an interpretation of directed percolation as an epidemic process, this non-Markovian modification can be understood as incubation times, which are distributed accordingly to a Levy distribution. We argue that the best appro

A. Merloni, S. Nayakshin

Observational evidence accumulated over the past decade indicates that accretion discs in X-ray binaries are viscously stable unless they accrete very close to the Eddington limit. This is at odds with the most basic standard accretion disc theory, but could be explained by either having the discs to be much cooler whereby they are not radiation pressure dom

E. C. Marino, Lizardo H. C. M. Nunes

We present a theory describing the superconducting (SC) interaction of Dirac electrons in a quasi-two-dimensional system consisting of a stack of N planes. The occurrence of a SC phase is investigated both at T=0 and T\neq 0, in the case of a local interaction, when the theory must be renormalized and also in the situation where a natural physical cutoff is

Nariya Kawazumi

Let ${\mathbb M}_{g, 1}$, $g \geq 1$, be the moduli space of triples $(C, P_0, v)$ of genus $g$, where $C$ is a compact Riemann surface of genus $g$, $P_0 \in C$, and $v \in T_{P_0}C\setminus\{0\}$. Using Chen&#39;s iterated integrals we introduce a higher analogue of the period matrix for a triple $(C, P_0, v)$, {\it the harmonic Magnus expansion}. It induc

Victor H. Cardenas

We study the possibility to construct an observationally viable scenario where both early Inflation and the recently detected accelerated expansion of the universe can be explained by using a single scalar field associated with the Tachyon. The Reheating phase becomes crucial to enable us to have a consistent cosmology and also to get a second accelerated ex

Pierre Martinetti

We give an overview on the metric aspect of noncommutative geometry, especially the metric interpretation of gauge fields via the process of &#34;fluctuation of the metric&#34;. Connes&#39; distance formula associates to a gauge field on a bundle P equipped with a connection H a metric. When the holonomy is trivial, this distance coincides with the horizonta

K. Sengupta, N. Dupuis, P. Majumdar

We study an atomic Bose-Fermi mixture in an optical lattice which is confined using an optical trap. We obtain the Mott ground states of such a system in the limit of deep optical lattice and discuss the effect of quantum fluctuations on these states. We also study the superfluid-insulator transitions of bosons and metal-insulator transition of fermions in s

R. P. Malik

We provide an alternative to the gauge covariant horizontality condition which is responsible for the derivation of the nilpotent (anti-)BRST symmetry transformations for the gauge and (anti-)ghost fields of a (3 + 1)-dimensional (4D) interacting 1-form non-Abelian gauge theory in the framework of the usual superfield approach to Becchi-Rouet-Stora-Tyutin (B

K. S. Andrikopoulos, D. Christofilos, G. A. Kourouklis, S. N. Yannopoulos

A detailed pressure-dependence study of the low-energy excitations of glassy As2S3 is reported over a wide pressure range, up to 10 GPa. The spectral features of Boson peak are analysed as a function of pressure. Pressure effects on the Boson peak are manifested as an appreciable shift of its frequency to higher values, a suppression of its intensity, as wel

G. Wilk, Z. Wlodarczyk

Examples of joint probability distributions are studied in terms of Tsallis&#39; nonextensive statistics both for correlated and uncorrelated variables, in particular it is explicitely shown how correlations in the system can make Tsallis entropy additive and that the effective nonextensivity parameter $q_N$ decreases towards unity when the number of variabl

Ahmad Nawaz, A. H. Toor

We analyze quantum game with correlated noise through generalized quantization scheme. Four different combinations on the basis of entanglement of initial quantum state and the measurement basis are analyzed. It is shown that the advantage that a quantum player can get by exploiting quantum strategies is only valid when both the initial quantum state and the

Onder Aslan, Durmus A. Demir

We discuss effective interactions among brane matter induced by modifications of higher dimensional Einstein gravity through the replacement of Einstein-Hilbert term with a generic function f(R, R_AB R^AB, R_ABCD R^ABCD) of the curvature tensors. We determine gravi-particle spectrum of the theory, and perform a comparative analysis of its predictions with th

Mats Granath

We study a model of a stripe ordered doped antiferromagnet consisting of coupled Hubbard ladders which can be tuned from quasi-one-dimensional to two-dimensional. We solve for the magnetization and charge density on the ladders by Hartree-Fock theory and find a set of solutions with lightly doped ``spin-stripes&#39;&#39; which are antiferromagnetic and more

Sanjay K. Ghosh, Tamal K. Mukherjee, Munshi G. Mustafa, Rajarshi Ray

We present the Taylor expansion coefficients of the pressure in quark number chemical potential $μ_0=μ_B / 3=μ_u=μ_d$, for the strongly interacting matter as described by the PNJL model for two light degenerate flavours of quarks u and d. The expansion has been done upto eighth order in $μ_0$, and the results are consistent with recent estimates from Lattice

Metod Saniga, Michel Planat

The paper deals with the projective line over the finite factor ring $R\_{\clubsuit} \equiv$ GF(2)[$x$]/$<x^{3} - x>$. The line is endowed with 18 points, spanning the neighbourhoods of three pairwise distant points. As $R\_{\clubsuit}$ is not a local ring, the neighbour (or parallel) relation is not an equivalence relation so that the sets of neighbour poin

H. Kempa, P. Esquinazi, Y. Kopelevich

We present Hall effect measurements on highly oriented pyrolytic graphite that indicate the occurrence of the integer quantum-Hall-effect. The evidence is given by the observation of regular plateau-like structures in the field dependence of the transverse conductivity obtained in van der Pauw configuration. Measurements with the Corbino-disk configuration s

Anirban Saha, Anisur Rahaman, Pradip Mukherjee

The 1+1 dimensional bosonised Schwinger model has been studied in a noncommutative scenario. The theory in the reduced phase space exhibits a massive boson interacting with a background. The emergence of this background interaction is a novel feature due to noncommutativity. The structure of the theory ensures unitarity and causality.

Nicolas Chamel, Pawel Haensel

Hydrodynamical simulations of neutron star cores, based on a two fluid description in terms of a neutron-proton superfluid mixture, require the knowledge of the Andreev-Bashkin entrainment matrix which relates the momentum of one constituent to the currents of both constituents. This matrix is derived for arbitrary nuclear asymmetry at zero temperature and i