March 2006 arXiv papers — page 31

Lu Li, Zaidong Li, Boris A. Malomed, Dumitru Mihalache

We find one-, two-, and three-component solitons of the polar and ferromagnetic (FM) types in the general (non-integrable) model of a spinor (three-component) model of the Bose-Einstein condensate (BEC), based on a system of three nonlinearly coupled Gross-Pitaevskii equations. The stability of the solitons is studied by means of direct simulations, and, in

Arthur W. Apter, James Cummings, Joel David Hamkins

We show, assuming the consistency of one measurable cardinal, that it is consistent for there to be exactly kappa+ many normal measures on the least measurable cardinal kappa. This answers a question of Stewart Baldwin. The methods generalize to higher cardinals, showing that the number of lambda strong compactness or lambda supercompactness measures on P_ka

Ron M. Adin, Yuval Roichman

For a permutation $π$ in the symmetric group $S_n$ let the {\it total degree} be its valency in the Hasse diagram of the strong Bruhat order on $S_n$, and let the {\it down degree} be the number of permutations which are covered by $π$ in the strong Bruhat order. The maxima of the total degree and the down degree and their values at a random permutation are

C. M. Hull, R. A. Reid-Edwards

We find the bosonic sector of the gauged supergravities that are obtained from 11-dimensional supergravity by Scherk-Schwarz dimensional reduction with flux to any dimension D. We show that, if certain obstructions are absent, the Scherk-Schwarz ansatz for a finite set of D-dimensional fields can be extended to a full compactification of M-theory, including

S. P. Baranov, V. L. Slad

The total and differential cross sections for the production of triply charmed $Ω_{ccc}$ baryons in $e^{+}e^{-}$ annihilation are calculated at the $Z$-boson pole.

I. I. Bigi

The Standard Model despite its well-known short comings is unlikely to yield without offering stubborn resistance. There are compelling arguments that New Physics lurks around the TeV scale. Continuing comprehensive studies of beauty, $τ$ and charm transitions can be instrumentalized to reveal it and shed light on it. They are thus complementary to findings

Tian Gui-hua, Shi-kun Wang, Shuquan Zhong

The Klein-Gordon equation in the Rindler space-time is studied carefully. It is shown that the stable properties depend on using what time coordinate to define the initial time. If we use the Rindler time, the scalar field is stable. Alternatively, if we use the Minkowski time, the scalar field may be regarded unstable to some extent. Furthermore, the comple

Miklós Csűrös

This paper describes a linear-time algorithm that finds the longest stretch in a sequence of real numbers (``scores'') in which the sum exceeds an input parameter. The algorithm also solves the problem of finding the longest interval in which the average of the scores is above a fixed threshold. The problem originates from molecular sequence analysis

J. C. Neu, L. L. Bonilla

Classical theory of nucleation based on Becker-Doering equations and coarsening for a binary alloy.

Diego Kienle, Jorge I. Cerda, Avik W. Ghosh

We describe a semi-empirical atomic basis Extended Hückel Theoretical (EHT) technique that can be used to calculate bulk bandstructure, surface density of states, electronic transmission and interfacial chemistry of various materials within the same computational platform. We apply this method to study multiple technologically important systems, starting wit

Anne Bernheim-Groswasser, Roman Shusterman, Oleg Krichevsky

We adapt Fluorescence Correlation spectroscopy (FCS) formalism to the studies of the dynamics of semi-flexible polymers and derive expressions relating FCS correlation function to the longitudinal and transverse mean square displacements of polymer segments. We use the derived expressions to measure the dynamics of actin filaments in two experimental situati

Forrest R. Bradbury, Alexei M. Tyryshkin, Guillaume Sabouret, Jeff Bokor

We report Stark shift measurements for 121Sb donor electron spins in silicon using pulsed electron spin resonance. Interdigitated metal gates on top of a Sb-implanted 28Si epi-layer are used to apply electric fields. Two Stark effects are resolved: a decrease of the hyperfine coupling between electron and nuclear spins of the donor and a decrease in electron

V. Sorkin, E. Polturak, Joan Adler

Using Path Integral Monte Carlo and the Maximum Entropy method, we calculate the dynamic structure factor of solid He-3 in the bcc phase at a finite temperature of T = 1.6 K and a molar volume of 21.5 cm^3. From the single phonon dynamic structure factor, we obtain both the longitudinal and transverse phonon branches along the main crystalline directions, [0

Yuki Kawaguchi, Hiroki Saito, Masahito Ueda

The general properties of the order parameter for a dipolar spinor Bose-Einstein condensate are discussed based on symmetries of interactions. An initially spin-polarized dipolar condensate is shown to dynamically generate a non-singular vortex via spin-orbit interactions -- a phenomenon reminiscent of the Einstein--de Haas effect in ferromagnets.

H. Andernach, K. Alamo-Martinez, R. Coziol, E. Tago

We identified Brightest Cluster Members (BCM) on DSS images of 1083 Abell clusters, derived their individual and host cluster redshifts from literature and determined the BCM ellipticity. Half the BCMs move at a speed higher than 37 % of the cluster velocity dispersion sigma_{cl}, suggesting that most BCMs are part of substructures falling into the main clus

Re'em Sari, Peter Goldreich

We compare different examples of spherical accretion onto a gravitating mass. Limiting cases include the accretion of a collisionally dominated fluid and the accretion of collisionless particles. We derive expressions for the accretion rate and density profile for semi-collisional accretion which bridges the gap between these limiting cases. Particle crossin

Elizabeth H. Wehner, John S. Gallagher, Gwen C. Rudie, Philip J. Cigan

II Zwicky 23 (UGC 3179) is a luminous, nearby compact narrow emission line starburst galaxy with blue optical colors and strong emission lines. We present a photometric and morphological study of II Zw 23 and its interacting companions using data obtained with the WIYN 3.5-m telescope in Kitt Peak, Arizona. II Zwicky 23 has a highly disturbed outer structure

G. A. Bakos, H. Knutson, F. Pont, C. Moutou

We report on the BVRI multi-band follow-up photometry of the transiting extrasolar planet HD 189733b. We revise the transit parameters and find planetary radius RP = 1.154+/- 0.032RJ and inclination i_P = 85.79+/-0.24deg. The new density (~ 1g cm-3) is significantly higher than the former estimate (~ 0.75g cm-3); this shows that from the current sample of 9

Sohei Kondo, Naoto Kobayashi, Yosuke Minowa, Takuji Tsujimoto

A Near-infrared (1.18-1.35 micron) high-resolution spectrum of the gravitationally-lensed QSO APM 08279+5255 was obtained with the IRCS mounted on the Subaru Telescope using the AO system. We detected strong NaI D 5891,5897 doublet absorption in high-redshift DLAs at z=1.062 and 1.181, confirming the presence of NaI, which was first reported for the rest-fra

M. Cignoni, Steven N. Shore

We present an application of the Richardson-Lucy algorithm to the analysis of color-magnitude diagrams by converting the CMD into an image and using a restoring point spread function function ({\it psf}) derived from the known, often complex, sources of error. We show numerical experiments that demonstrate good recovery of the original image and establish co

Alejandro D. Quintero, Andreas A. Berlind, Michael R. Blanton, David W. Hogg

We investigate the extent to which galaxies' star-formation histories and morphologies are determined by their clustocentric distance and their nearest cluster's richness. We look at three tracers of star-formation history (i-band absolute magnitude M_i, [g-r] color, and Halpha emission line equivalent width) and two indicators of galaxy morphology (

L. M. Oskinova, A. Feldmeier, W. -R. Hamann

Archival X-ray spectra of the four prominent single, non-magnetic O stars Zeta Pup, Zeta Ori, Ksi Per and Zeta Oph, obtained in high resolution with Chandra HETGS/MEG have been studied. The resolved X-ray emission line profiles provide information about the shocked, hot gas which emits the X-radiation, and about the bulk of comparably cool stellar wind mater

Arne Rau, Jochen Greiner, Robert Schwarz

Gamma-ray bursts are believed to be produced in highly-relativistic collimated outflows. Support for this comes among others from the association of the times of detected breaks in the decay of afterglow light curves with the collimation angle of the jets. An alternative approach to estimate a limit on the collimation angle uses GRB afterglows without detect

Olivera Miskovic, Rodrigo Olea

A finite action principle for three-dimensional gravity with negative cosmological constant, based on a boundary condition for the asymptotic extrinsic curvature, is considered. The bulk action appears naturally supplemented by a boundary term that is one half the Gibbons-Hawking term, that makes the Euclidean action and the Noether charges finite without ad

Krzysztof Pachucki

Improved theoretical predictions for the fine-structure splitting of $2^3P_J$ levels in helium are obtained by the calculation of contributions of order $α^5 Ry$. New results for transition frequencies, $ν_{01} = 29 616 943.01(17)$ kHz and $ν_{12} = 2 291 161.13(30)$ kHz disagree significantly with the experimental values, indicating an outstanding problem i

Pavel Etingof, Victor Ginzburg

We introduce a class of noncommutatative algebras called representation complete intersections (RCI). A graded associative algebra A is said to be RCI provided there exist arbitrarily large positive integers n such that the scheme Rep_n(A), of n-dimensional representations of A, is a complete intersection. We discuss examples of RCI algebras, including those

John F. Wambaugh

A remarkable feature of static granular matter is the distribution of force along intricate networks. Even regular inter-particle contact networks produce wildly inhomogeneous force networks where certain "chains" of particles carry forces far larger than the mean. In this paper, we briefly review past theoretical approaches to understanding the geom

Gerardo A. Paz-Silva, John H. Reina

Within the framework of constructions for quantifying entanglement, we build a natural scenario for the assembly of multipartite entanglement measures based on Hopf bundle-like mappings obtained through Clifford algebra representations. Then, given the non-factorizability of an arbitrary two-qubit density matrix, we give an alternate quantity that allows the

H. Belich, T. Costa-Soares, M. M. Ferreira, J. A. Helayel-Neto

Recently, a scheme to analyse topological phases in Quantum Mechanics by means of the non-relativistic limit of fermions non-minimally coupled to a Lorentz-breaking background has been proposed. In this letter, we show that the fixed background, responsible for the Lorentz-symmetry violation, may induce opposite Aharonov-Casher phases for a particle and its

J. T. Kosloski

Several simple yet secure protocols to authenticate the quantum channel of various QKD schemes, by coupling the photon sender's knowledge of a shared secret and the QBER Bob observes, are presented. It is shown that Alice can encrypt certain portions of the information needed for the QKD protocols, using a sequence whose security is based on computationa

Marc Freitag, Pau Amaro-Seoane, Vassiliki Kalogera

The study of how stars distribute themselves around a massive black hole (MBH) in the center of a galaxy is an important prerequisite for the understanding of many galactic-center processes. These include the observed overabundance of point X-ray sources at the Galactic center, the prediction of rates and characteristics of tidal disruptions of extended star

Nick Gill

A long-standing conjecture is that any transitive finite projective plane is Desarguesian. We make a contribution towards a proof of this conjecture by showing that a group acting transitively on the the points of a non-Desarguesianprojective plane must not contain any components.

G. Nenciu

We point out a general argument leading from the formula for currents through an open mesoscopic system given by the theory of non-equilibrium steady states (NESS) to the Landauer-Büttiker formula.

Masawo Nakane, Yoshiyuki Fukumoto, Akihide Oguchi

Using the bosonization and level spectroscopy methods, we study the ground-state phase diagram of a XXZ antiferromagnet on a railroad-trestle lattice with asymmetric leg interactions. It is shown that the asymmetry does not change the dimer/Neel transition line significantly, which agrees with the expectation based on a naive bosonization procedure, but it d

T. Shibauchi, L. Krusin-Elbaum, Y. Kasahara, Y. Shimono

The entire temperature dependence of the upper critical field $H_{\rm c2}$ in the $β$-pyrochlore KOs$_2$O$_6$ is obtained from high-field resistivity and magnetic measurements. Both techniques identically give $H_{\rm c2}(T \simeq 0 {\rm K})$ not only surprisingly high ($\sim 33$ T), but also the approach to it unusually temperature-\emph{linear} all the way

Chunhui Lai, Lili Hu

Let $K_k$, $C_k$, $T_k$, and $P_{k}$ denote a complete graph on $k$ vertices, a cycle on $k$ vertices, a tree on $k+1$ vertices, and a path on $k+1$ vertices, respectively. Let $K_{m}-H$ be the graph obtained from $K_{m}$ by removing the edges set $E(H)$ of the graph $H$ ($H$ is a subgraph of $K_{m}$). A sequence $S$ is potentially $K_{m}-H$-graphical if it

Alexander Kvinikhidze, Gerald A. Miller

Previously defined spin-dependent quark densities that are matrix elements of specific density operators in proton states of definite spin-polarization generally have an infinite variety of non-spherical shapes. The present application is concerned with both charge and matter densities. We show that the Gross & Agbakpe model nucleon harbors an interesting va

S. Campana, V. Mangano, A. J. Blustin, P. Brown

Although the link between long Gamma Ray Bursts (GRBs) and supernovae (SNe) has been established, hitherto there have been no observations of the beginning of a supernova explosion and its intimate link to a GRB. In particular, we do not know however how a GRB jet emerges from the star surface nor how a GRB progenitor explodes. Here we report on observations

Shao-Ming Fei, Xianqing Li-Jost, Bao-Zhi Sun

We construct a set of PPT (positive partial transpose) states and show that these PPT states are not separable, thus present a class of bound entangled quantum states.

Bao-Zhi Sun, Shao-Ming Fei, Xianqing Li-Jost, Zhi-Xi Wang

The equivalence of arbitrary dimensional bipartite states under local unitary transformations (LUT) is studied. A set of invariants and ancillary invariants under LUT is presented. We show that two states are equivalent under LUT if and only if they have the same values for all of these invariants.

Shao-Ming Fei, Naihuan Jing, Bao-Zhi Sun

The approximation of matrices to the sum of tensor products of Hermitian matrices is studied. A minimum decomposition of matrices on tensor space $H_1\otimes H_2$ in terms of the sum of tensor products of Hermitian matrices on $H_1$ and $H_2$ is presented. From this construction the separability of quantum states is discussed.

Jian Wang, Quan Zhang, Chao-jing Tang

Based on the ideal of order rearrangement and block transmission of photons, we present a quantum secure direct communication scheme using single photons. The security of the present scheme is ensured by quantum no-cloning theory and the secret transmitting order of photons. The present scheme is efficient in that all of the polarized photons are used to tra

Farhan Saif

We investigate the quantum recurrence phenomena in periodically driven systems. We calculate the classical period and the quantum recurrence time and develop their interdependence. We further predict the behavior of the recurrence phenomena for the power law potentials.

Karl Svozil

All experimental tests of Bell-type inequalities and Greenberger-Horne-Zeilinger setups rely on the separate and successive measurement of the terms involved. We discuss possibilities of experimental setups to measure all relevant terms simultaneously in a single experiment and find this to be impossible. One reason is the lack of multi-partite states which

Wei-Rong Zhong, Yuan-Zhi Shao, Zhen-Hui He

We report on a simple model of spatial extend anti-tumor system with a fluctuation in growth rate, which can undergo a nonequilibrium phase transition. Three states as excited, sub-excited and non-excited states of a tumor are defined to describe its growth. The multiplicative noise is found to be double-face: The positive effect on a non-excited tumor and t

Victor N. Pervushin

Possibilities for solution of the problem of creation of the Universe from a physical vacuum in the framework the General Relativity and modern quantum field theory are discussed in the context of the official doctrine accepted in Trinity College at the Newton time.

Jian You Guo, Xiang Zheng Fang

The relativistic mean field theory in combination with the analytic continuation in the coupling constant method is used to determine the energies and widths of single-particle resonant states in Sn isotopes. It is shown that there exists clear shell structure in the resonant levels as appearing in the bound levels. In particular, the isospin dependence of p

Madhekar Suneel

An electronic circuit realization of the logistic difference equation is presented using analog electronics. The behavior of the realized system is evaluated against computer simulations of the same. The circuit is found to exhibit the entire range of dynamics of the logistic equation: fixed points, periodicity, period doubling, chaos and intermittency. Quan

K. P. Harikrishnan, R. Misra, G. Ambika, A. K. Kembhavi

We present an adaptation of the standard Grassberger-Proccacia (GP) algorithm for estimating the Correlation Dimension of a time series in a non subjective manner. The validity and accuracy of this approach is tested using different types of time series, such as, those from standard chaotic systems, pure white and colored noise and chaotic systems added with

Nicolae Cotfas

A hypergeometric type equation satisfying certain conditions defines either a finite or an infinite system of orthogonal polynomials. The associated special functions are eigenfunctions of some shape invariant operators. These operators can be analysed together and the mathematical formalism we use can be extended in order to define other shape invariant ope

Jouko Mickelsson

The basic mechanism how gerbes arise in quantum field theory is explained; in particular the case of chiral fermions in background fields is treated. The role of of various gauge group extensions (central extensions of loop groups and their generalizations) is also explained, in relation to index theory computation of the Dixmier-Douady class of a gerbe.

Frederik J Simons, F. A. Dahlen

The estimation of potential fields such as the gravitational or magnetic potential at the surface of a spherical planet from noisy observations taken at an altitude over an incomplete portion of the globe is a classic example of an ill-posed inverse problem. Here we show that the geodetic estimation problem has deep-seated connections to Slepian's spatio

David E. Radford, Hans-Jürgen Schneider

Let $U$ and $A$ be algebras over a field $k$. We study algebra structures $H$ on the underlying tensor product $U{\otimes}A$ of vector spaces which satisfy $(u{\otimes}a)(u'{\otimes}a') = uu'{\otimes}aa'$ if $a = 1$ or $u' = 1$. For a pair of characters $ρ\in \Alg(U, k)$ and $χ\in \Alg(A, k)$ we define a left $H$-module $L(ρ, χ)$. Under r

David E. Radford, Hans-Jürgen Schneider

We parameterize the finite-dimensional irreducible representations of a class of pointed Hopf algebras over an algebraically closed field of characteristic zero by dominant characters. The Hopf algebras we are considering arise in the work of N. Andruskiewitsch and the second author. Special cases are the multiparameter deformations of the enveloping algebra

David E. Radford, Hans-Jürgen Schneider

Let $H$ be a Hopf algebra with bijective antipode over a field $k$ and suppose that $R{#}H$ is a bi-product. Then $R$ is a bialgebra in the Yetter--Drinfel'd category ${}_H^H{\mathcal YD}$. We describe the bialgebras $(R{#}H)^{op}$ and $(R{#}H)^o$ explicitly as bi-products $R^{\UOP}{#}H^{op}$ and $R^{\UO}{#}H^o$ respectively where $R^{\UOP}$ is a bialgeb

Régis Blache, Eric Férard

In this paper we consider the Newton polygons of $L$-functions coming from additive exponential sums associated to a polynomial over a finite field $\F_q$. These polygons define a stratification of the space of polynomials of fixed degree. We determine the open stratum: we give the generic Newton polygon for polynomials of degree $d\geq 2$ when the character

Jose A. Heras

We discuss the Kirchhoff gauge in classical electrodynamics. In this gauge the scalar potential satisfies an elliptical equation and the vector potential satisfies a wave equation with a nonlocal source. We find the solutions of both equations and show that, despite of the unphysical character of the scalar potential, the electric and magnetic fields obtaine

J. Lopez-Sarrion, E. F. Moreno, F. A. Schaposnik, D. Slobinsky

We study a d=2+1 dimensional Chern-Simons gauge theory coupled to a Higgs scalar and an axion field, finding the form of the potential that allows the existence of selfdual equations and the corresponding Bogomolny bound for the energy of static configurations. We show that the same conditions allow for the N=2 supersymmetric extension of the model, reobtain

Maria Laura Alciati, Ferruccio Feruglio, Yin Lin, Alvise Varagnolo

We propose a minimal SO(10) model in 5 space-time dimensions. The single extra spatial dimension is compactified on the orbifold S^1/(Z_2 x Z_2') reducing the gauge group to that of Pati-Salam. The breaking down to the standard model group is obtained through an ordinary Higgs mechanism taking place at the Pati-Salam brane, giving rise to a proper gauge

Parampreet Singh

The discrete quantum geometric effects play an important role in dynamical evolution in the loop quantum cosmology. These effects which are significant at the high energies lead to the quadratic energy density modifications to the Friedmann equation, as in the Randall-Sundrum braneworld scenarios but with a negative sign. We investigate the scalar field dyna

V. A. De Lorenci, R. Klippert, D. H. Teodoro

Light propagation is investigated in the context of local anisotropic nonlinear dielectric media at rest with the dielectric coefficients $ε^μ_ν= ε^μ_ν(\vec{E},\vec{B})$ and constant $μ$, in the limit of geometrical optics. Birefringence was examined and the general conditions for its occurrence were presented. A toy model is exhibited, in which uniaxial bir

Charles W. Misner

This preliminary report proposes integrating the Maxwell equations in Minkowski spacetime using coordinates where the spacelike surfaces are hyperboloids asymptotic to null cones at spatial infinity. The space coordinates are chosen so that Scri+ occurs at a finite coordinate and a smooth extension beyond Scri+ is obtained. The question addressed is whether

S. Torquato, F. H. Stillinger

We introduce a generalization of the well-known random sequential addition (RSA) process for hard spheres in $d$-dimensional Euclidean space $\mathbb{R}^d$. We show that all of the $n$-particle correlation functions of this nonequilibrium model, in a certain limit called the "ghost" RSA packing, can be obtained analytically for all allowable densitie

T. Jeong

The electronic structure of $β$-Ti$_{6}$Sn$_{5}$ has been studied based on the density functional theory within the local-density approximation. The calculation indicates that $β$-Ti$_{6}$Sn$_{5}$ is very close to ferromagnetic instability and shows ferromagnetic ordering after rare earth element doping. Large enhancement of the static susceptibility over it

Jinfeng Wang, P. Fraundorf, Yangchuan Xing

Carbon nanotubes are of potential interest as heterogeneous catalysis supports, in part because they offer a high surface area hexagonal array of carbon atoms for columnar or epitaxial attachment. Fringe visibility modeling of electron microscope lattice images allows one to investigate the relationship between individual nanoparticles and such nanotube supp

Shin-Tza Wu, S. -K. Yip

We study current fluctuations in a phase coherent Y-shaped conductor connected to external leads and voltage probes. The voltage probes are taken to have finite impedances and thus can cause voltage fluctuations in the circuit. Applying the Keldysh formulation and a saddle point approximation appropriate for slow fluctuations, we examine at zero temperature

Yng-Gwei Chen, John D. Weeks

Strong short ranged positional correlations involving counterions can induce a net attractive force between negatively charged strands of DNA, and lead to the formation of ion pairs in dilute ionic solutions. But the long range of the Coulomb interactions impedes the development of a simple local picture. We address this general problem by mapping the proper

J. Koda, Y. Sofue

We present CO interferometer observations of the barred galaxy NGC 4303 (M61). This galaxy has a gas concentration at the central region and offset ridges in the bar. Sharp velocity gradients are apparent across the ridges. Analyses of the CO data and the newborn stellar clusters revealed in HST images indicate the existence of unresolved molecular clouds wi

D. I. Nagirner S. L. Kirusheva

We have derived the radiative-transfer equation for a point source with a specified intensity and spectrum, originating in the early Universe between the epochs of annihilation and recombination, at redshifts $z_\s =10^8÷10^4$. The direct radiation of the source is separated from the diffuse radiation it produces. Optical distances from the source for Thomso

Joseph C. Weingartner

Several mechanisms have been proposed to explain the alignment of grains with the interstellar magnetic field, including paramagnetic dissipation, radiative torques, and supersonic gas-grain streaming. These must compete with disaligning processes, including randomly directed torques arising from collisions with gas atoms. I describe a novel disalignment mec

A. J. Levan, N. R. Tanvir, A. S. Fruchter, E. Rol

We present optical and X-ray observations of the afterglow and host galaxy of the short-hard GRB 060121. The faint R-band afterglow is seen to decline as t^(-0.66) while the X-ray falls as t^-1.18, indicating the presence of the cooling break between the two frequencies. However, the R-band afterglow is very faint compared to the predicted extrapolation of t

R. Misra, K. P. Harikrishnan, G. Ambika, A. K. Kembhavi

Using non-linear time series analysis, along with surrogate data analysis, it is shown that the various types of long term variability exhibited by the black hole system GRS 1915+105, can be explained in terms of a deterministic non-linear system with some inherent stochastic noise. Evidence is provided for a non-linear limit cycle origin of one of the low f

Hans-Andreas Engel, Emmanuel I. Rashba, Bertrand I. Halperin

Spin Hall effects are a collection of phenomena, resulting from spin-orbit coupling, in which an electrical current flowing through a sample can lead to spin transport in a perpendicular direction and spin accumulation at lateral boundaries. These effects, which do not require an applied magnetic field, can originate in a variety of intrinsic and extrinsic s

Anirban Basu, Linda I. Uruchurtu

We construct the gauge invariant part of the propagator for the massless gravitino in AdS(d+1) by coupling it to a conserved current. We also derive the propagator for the massive gravitino.

Saugata Basu

For any $\ell > 0$, we present an algorithm which takes as input a semi-algebraic set, $S$, defined by $P_1 \leq 0,...,P_s \leq 0$, where each $P_i \in \R[X_1,...,X_k]$ has degree $\leq 2,$ and computes the top $\ell$ Betti numbers of $S$, $b_{k-1}(S), ..., b_{k-\ell}(S),$ in polynomial time. The complexity of the algorithm, stated more precisely, is $ \sum_

Hendrik van Hees, Ralf Rapp

Employing thermal dilepton rates based on medium-modified electromagnetic correlation functions we show that recent dimuon spectra of the NA60 collaboration in central In-In collisions at the CERN-SPS can be understood in terms of radiation from a hot and dense hadronic medium. Earlier calculated ρ-meson spectral functions, as following from hadronic many-bo

L. Angers, E. Zakka-Bajjani, R. Deblock, S. Gueron

Fundamental Casimir-Onsager symmetry rules for linear response do not apply to non linear transport. This motivates the investigation of nonlinear dc conductance of mesoscopic GaAs/GaAlAs rings in a 2 wire configuration. The second order current response to a potential bias is of particular interest. It is related to the sensitivity of conductance fluctuatio

Daniel Hernández Ruipérez, Carlos Tejero Prieto

We determine all the Fourier-Mukai transforms for coherent systems consisting of a vector bundle over an elliptic curve and a subspace of its global sections, showing that these transforms are indexed by the positive integers. We prove that the natural stability condition for coherent systems, which depends on a parameter, is preserved by these transforms fo

Jon Yard, Patrick Hayden, Igor Devetak

We consider quantum channels with one sender and two receivers, used in several different ways for the simultaneous transmission of independent messages. We begin by extending the technique of superposition coding to quantum channels with a classical input to give a general achievable region. We also give outer bounds to the capacity regions for various spec

Eivind Eriksen

Let k be an algebraically closed field of characteristic 0, and let $A = k[x,y]/(f)$ be a quasi-homogeneous plane curve. We show that for any graded torsion free A-module M, there exists a natural graded integrable connection, i.e. a graded A-linear homomorphism $\nabla: \operatorname{Der}_k(A) \to \operatorname{End}_k(M)$ that satisfy the derivation propert

S. Moretti, M. R. Nolten, D. A. Ross

We calculate purely weak virtual one-loop corrections to the production cross section of top-antitop pairs at the Large Hadron Collider via the gluon-gluon fusion subprocess. We find very small negative corrections to the total cross section, of order -0.6%, but significantly larger effects to the differential one, particularly in the transverse momentum dis

Kristian Pedersen, Haakon Dahle

The main uncertainty in current determinations of the power spectrum normalization, sigma_8, from abundances of X-ray luminous galaxy clusters arises from the calibration of the mass-temperature relation. We use our weak lensing mass determinations of 30 clusters from the hitherto largest sample of clusters with lensing masses, combined with X-ray temperatur

Saugata Basu, Richard Pollack, Marie-Francoise Roy

We prove an asymptotically tight bound (asymptotic with respect to the number of polynomials for fixed degrees and number of variables) on the number of semi-algebraically connected components of the realizations of all realizable sign conditions of a family of real polynomials. More precisely, we prove that the number of semi-algebraically connected compone

Robert D. Bock

We present a solution to the time discontinuity paradox in rotating reference frames by postulating that time is periodic. A kinematic restriction is enforced that requires the discontinuity to be an integral number of the periodicity of time. Quantized radii emerge for which the associated tangential velocities are less than the speed of light. Using the de

Y. -Y. Zhang, H. Boehringer, A. Finoguenov, Y. Ikebe

We selected an unbiased, flux-limited and almost volume-complete sample of 13 distant, X-ray luminous (DXL, $z\sim 0.3$) clusters and one supplementary cluster at $z=0.2578$ from the REFLEX Survey (the REFLEX-DXL sample). We performed a detailed study to explore their X-ray properties using XMM-Newton observations. Based on the precise radial distributions o

Marshall Spight, Vadim Tropashko

Relational lattice reduces the set of six classic relational algebra operators to two binary lattice operations: natural join and inner union. We give an introduction to this theory with emphasis on formal algebraic laws. New results include Spight distributivity criteria and its applications to query transformations.

A. F. Ho

We study a model of an equal mixture of two species of fermions in a deep optical lattice at a filling of two fermions per site. At weak inter-species interaction, the system is a band insulator. When the inter-species interaction is tuned via a Feshbach resonance to be larger than an energy related to the energy separation of the first and second Bloch band

Hans Peter Nilles, Saul Ramos-Sanchez, Patrick K. S. Vaudrevange, Akin Wingerter

We give a complete classification of Z_N orbifold compactification of the heterotic SO(32) string theory and show its potential for realistic model building. The appearance of spinor representations of SO(2n) groups is analyzed in detail. We conclude that the heterotic SO(32) string constitutes an interesting part of the string landscape both in view of mode

Gerasim Kokarev

We explore a relationship between topological properties of orbits of 2-cycles in the symplectomorphism group Symp(M) and the existence of rational curves in M. Under the absence of rational curves hypothesis, we show that evaluation map vanishies on the second homotopy group and obtain a Gottlieb-type vanishing theorem for toroidal cycles in Symp(M).

A. C. Carciofi, A. S. Miroshnichenko, A. V. Kusakin, J. E. Bjorkman

We present optical $WBVR$ and infrared $JHKL$ photometric observations of the Be binary system $δ$ Sco, obtained in 2000--2005, mid-infrared (10 and $18 μ$m) photometry and optical ($λλ$ 3200--10500 Å) spectropolarimetry obtained in 2001. Our optical photometry confirms the results of much more frequent visual monitoring of $δ$ Sco. In 2005, we detected a si

Nicolas Ragache, Olivier Wintenberger

Assuming that $(X_t)_{t\in\Z}$ is a vector valued time series with a common marginal distribution admitting a density $f$, our aim is to provide a wide range of consistent estimators of $f$. We consider different methods of estimation of the density as kernel, projection or wavelets ones. Various cases of weakly dependent series are investigated including th

Hosein Cheraghchi

Validity of the single parameter scaling (SPS) in one dimensional Anderson model with purely off-diagonal disorder is being studied. It is shown that the localized region with standard symmetry is divided into two regimes: SPS and non-SPS. Scaling relations of the Lyapunov Exponent are proposed for these two regimes. In the non-SPS regime, in additional to t

Matthieu Wyart, Jean-Philippe Bouchaud, Julien Kockelkoren, Marc Potters

We show that the cost of market orders and the profit of infinitesimal market-making or -taking strategies can be expressed in terms of directly observable quantities, namely the spread and the lag-dependent impact function. Imposing that any market taking or liquidity providing strategies is at best marginally profitable, we obtain a linear relation between

Leah Jager, Jon A. Wellner

A unified family of goodness-of-fit tests based on $ϕ$-divergences is introduced and studied. The new family of test statistics $S_n(s)$ includes both the supremum version of the Anderson--Darling statistic and the test statistic of Berk and Jones [Z. Wahrsch. Verw. Gebiete 47 (1979) 47--59] as special cases ($s=2$ and $s=1$, resp.). We also introduce integr

Yoshihiko Nonomura, Xiao Hu

The ground state of interlayer Josephson vortex systems is investigated on the basis of a simplified Lawrence-Doniach model in which spatial dependence of the gauge field and the amplitude of superconducting order parameter is not taken into account. Energy landscape is drawn with respect to the in-plane field, the period of insulating layers including Josep

E. Perfetto, J. Gonzalez

We devise an approach to describe the electronic instabilities of doped multi-walled nanotubes, where each shell has in general a manifold of Fermi points. Our analysis relies on the scale dependence of the different scattering processes, showing that a pairing instability arises for a large enough number of Fermi points as a consequence of their particular

K. Eckert, L. Zawitkowski, M. J. Leskinen, A. Sanpera

We investigate magnetic properties of Mott-insulating phases of ultracold Bose and Fermi spinor gases in optical lattices. We consider in particular the F=2 Bose gas, and the F=3/2 and F=5/2 Fermi gases. We derive effective spin Hamiltonians for one and two atoms per site and discuss the possibilities of manipulating the magnetic properties of the system usi

Dongsu Bak

Starting from the Janus solution and its gauge theory dual, we obtain the dual gauge theory description of the cosmological solution by procedure of the double anaytic continuation. The coupling is driven either to zero or to infinity at the big-bang and big-crunch singularities, which are shown to be related by the S-duality symmetry. In the dual Yang-Mills

Roberto Emparan

We study the possibility that black hole entropy be identified as entropy of entanglement across the horizon of the vacuum of a quantum field in the presence of the black hole. We argue that a recent proposal for computing entanglement entropy using AdS/CFT holography implies that black hole entropy can be exactly equated with entanglement entropy. The imple

L. Foschini, G. Ghisellini, C. M. Raiteri, F. Tavecchio

(abridged) We performed a homogeneous and systematic analysis of simultaneous X-ray and optical/UV properties of a group of 15 gamma-ray loud AGN, using observations performed with XMM-Newton. The sample is composed of 13 blazars (6 BL Lac and 7 Flat-Spectrum Radio Quasar) and 2 radio galaxies, that are associated with detections at energies >100 MeV. The da