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June 2009 arXiv papers — page 31

Showing 3,0013,100 of 5,471 papers

  1. Wei-Ping Li, Zhenbo Qin

    The Gieseker-Uhlenbeck morphism maps the Gieseker moduli space of stable rank-2 sheaves on a smooth projective surface to the Uhlenbeck compactification, and is a generalization of the Hilbert-Chow morphism for Hilbert schemes of points. When the surface is the complex projective plane, we determine all the 1-point genus-0 Gromov-Witten invariants extremal w

  2. Artur Ruuge, Fred Van Oystaeyen

    In the present paper we study the following problem: how to construct a coherent orthoalgebra which has only a finite number of elements, but at the same time does not admit a bivaluation (i.e. a morphism with a codomain being an orthoalgebra with just two elements). This problem is important in the perspective of Bell-Kochen-Specker theory, since one can as

  3. Luisa Arlotti, Bertrand Lods, Mustapha Mokhtar-Kharroubi

    The object of this paper is twofold: In the first part, we unify and extend the recent developments on honesty theory of perturbed substochastic semigroups (on $L^{1}(μ)$-spaces or noncommutative $L^{1}$ spaces) to general state spaces; this allows us to capture for instance a honesty theory in preduals of abstract von Neumann algebras or subspaces of duals

  4. R. Candelier, O. Dauchot

    We investigate experimentally the dynamics of an intruder dragged by a constant force in an assembly of horizontally vibrated grains close to jamming. At moderate packing fractions, the intruder moves rapidly as soon as the force is applied. Above some threshold value of the packing fraction which increases with the applied force, the intruder exhibits an in

  5. Amalendu Krishna

    The goal of this paper is to prove a version of the non-abelian localization theorem for the rational equivariant K-theory of a smooth variety $X$ with the action of a linear algebraic group $G$. We then use this to prove a Riemann-Roch theorem which represents the completion of the higher equivariant K-theory of $X$ at various maximal ideals of the represen

  6. Hongjuan Wang, Chengcai Shen, Jun Lin

    The origin of the Moreton wave observed in the chromosphere and the EIT wave observed in the corona during the eruption remains being an active research subject for a while. We investigate numerically in this work the evolutionary features of the magnetic configuration that includes a current-carrying flux rope, which is used to model the filament, after the

  7. Pedro Bicudo, Joao Seixas, Marco Cardoso

    We fit the lattice QCD data of Kaczmarek et al for the free energy F1 and internal energy U1 with a class of Coulomb, constant and linear potentials, both pure and screened, matching the large distance to the short distance parts of the lattice QCD finite temperature energies. We also include the hyperfine potential in F1 and U1. We detail the bottomonium (a

  8. I. Bouras, A. El, O. Fochler, J. Uphoff

    Fast thermalization and a strong buildup of elliptic flow of QCD matter as found at RHIC are understood as the consequence of perturbative QCD (pQCD) interactions within the 3+1 dimensional parton cascade BAMPS. The main contributions stem from pQCD bremsstrahlung $2 \leftrightarrow 3 $ processes. By comparing to Au+Au data of the flow parameter $v_2$ the sh

  9. Kalobaran Maiti, Jorg Fink, Sanne de Jong, Mihaela Gorgoi

    The electronic structure of YBa2Cu3O6+x and La2-xSrxCuO4 for various values of x has been investigated using hard x-ray photoemission spectroscopy. The experimental results establish that the cleaving of YBa2Cu3O6+x compounds occurs predominantly in the BaCuO3 complex leading to charged surfaces at higher x and to uncharged surfaces at lower x values. The bu

  10. François Mauger, Cristel Chandre, T. Uzer

    The uncorrelated (``sequential'') and correlated (``nonsequential'') double ionization of the H2 molecule in strong laser pulses is investigated using the tools of nonlinear dynamics. We focus on the phase-space dynamics of this system, specifically by finding the dynamical structures that regulate these ionization processes. The emerging picture complements

  11. Catherine Doss, Michèle Thieullen

    We consider a stochastic perturbation of a FitzHugh-Nagumo system. We show that it is possible to generate oscillations for values of parameters which do not allow oscillations for the deterministic system. We also study the appearance of a new equilibrium point and new bifurcation parameters due to the noisy component.

  12. B. A. Kniehl, A. Sirlin

    We review two recently proposed on-shell schemes for the renormalization of the Cabibbo-Kobayashi-Maskawa (CKM) quark mixing matrix in the Standard Model. One first constructs gauge-independent mass counterterm matrices for the up- and down-type quarks complying with the hermiticity of the complete mass matrices. Diagonalization of the latter then leads to e

  13. A. T. Avelar, D. Bazeia, W. B. Cardoso, L. Losano

    In this work we investigate the presence of lump-like solutions in models described by a single real scalar field. We take advantage of a procedure recently used to describe explicit analytical solutions and we study several distinct models, showing how the parameters can be used to control the specific features of the lump-like structures. The proposed mode

  14. B. G. Giraud, P. Moussa

    We generalize a "one eigenstate" theorem of Levy, Perdew and Sahni (LPS) to the case of densities coming from eigenmixture density operators. The generalization is of a special interest for the radial density functional theory (RDFT) for nuclei, a consequence of the rotational invariance of the nuclear Hamiltonian; when nuclear ground states (GSs) ha

  15. Tobias Kretz

    This contribution investigates situations in pedestrian dynamics, where trying to walk the shortest path leads to largely different results than trying to walk the quickest path. A heuristic one-shot method to model the influence of the will to walk the quickest path is introduced.

  16. Svitlana Mayboroda, Alexander Volberg

    Following a recent paper by X. Tolsa and A. Ruiz de Villa [Non existence of principal values of signed Riesz transforms of non integer dimension, preprint], we show that the finiteness of square function associated with the Riesz transforms with respect to Hausdorff measure $H^s$ implies that $s$ is integer.

  17. Ken'ichi Sekiya

    Let $S$ be a compact Sasakian manifold which does not admit non-trivial Hamiltonian holomorphic vector fields. If there exists an Einstein-Sasakian metric on $S$, then it is unique.

  18. Svitlana Mayboroda, Alexander Volberg

    Following a recent paper by X. Tolsa [JFA, 2008] we show that the finiteness of square function associated with the Riesz transforms with respect to Hausdorff measure $H^n$ ($n$ is interger) on a set $E$ implies that $E$ is rectifiable.

  19. B. Viticchié, D. Del Moro, F. Berrilli, L. Bellot Rubio

    We present the results from first spectropolarimetric observations of the solar photosphere acquired at the Dunn Solar Telescope with the Interferometric Bidimensional Spectrometer. Full Stokes profiles were measured in the Fe I 630.15 nm and Fe I 630.25 nm lines with high spatial and spectral resolutions for 53 minutes, with a Stokes V noise of 0.003 the co

  20. Alessandra Andreoni, Maria Bondani

    In a macroscopic realm, in which photons are too many for being counted by any photon counting detector, photon statistics can be measured by using detectors simply endowed with linear response. We insert one of such detectors in a conventional photon-counting apparatus, which returns a voltage every time the detector responds to light by generating a number

  21. Debra Meloy Elmegreen, Bruce G. Elmegreen, Max T. Marcus, Karlen Shahinyan

    Clumpy galaxies in the GEMS and GOODS fields are examined for clues to their evolution into modern spirals. The magnitudes of the clumps and the surface brightnesses of the interclump regions are measured and fitted to models of stellar age and mass. There is an evolutionary trend from clump clusters with no evident interclump emission to clump clusters with

  22. C. Merino, M. M. Ryzhinskiy, Yu. M. Shabelski

    We consider the possible contribution of Odderon (Reggeon with alpha_(Odd)(0) similar to 1 and negative signature) exchange to the differences in the total cross sections of particle and antiparticle, to the ratios of real/imaginary parts of the elastic pp amplitude, and to the differences in the inclusive spectra of particle and antiparticle in the central

  23. R. Pandharipande

    The subalgebra of the tautological ring of the moduli of curves of compact type generated by the kappa classes is studied. Relations, constructed via the virtual geometry of the moduli of stable maps, are used to prove universality results relating the kappa rings in genus 0 to higher genus. Predictions for kappa classes of the Gorenstein conjecture are prov

  24. R. Pandharipande

    The subalgebra of the tautological ring of the moduli of curves of compact type generated by the kappa classes is studied in all genera. Relations, constructed via the virtual geometry of the moduli of stable quotients, are used to obtain minimal sets of generators. Bases and Betti numbers of the kappa rings are computed. A universality property relating the

  25. I. L. Drichko, A. M. Diakonov, E. V. Lebedeva, I. Yu. Smirnov

    Measurement results of the acoustoelectric effects (surface acoustic waves (SAW) attenuation and velocity) in a high-mobility $p$-SiGe/Ge/SiGe structure are presented. The structure was LEPECVD grown with a two dimensional (2D) channel buried in the strained Ge layer. The measurements were performed as a function of temperature (1.5 - 4.2 K) and magnetic fie

  26. Maciej Przanowski

    Relativistic thermodynamics as result of some recent computer simulations is derived.

  27. Larry McLerran

    The large Nc limit provides a good phenomenology of meson spectra and interactions. I discuss some problems with applying the large Nc approximation to the description of baryons, and point out a number of apparent paradoxes and phenomenological difficulties.

  28. Stefan Dittmaier, Michael Krämer, Michael Spira, Manuel Walser

    The dominant production process for heavy charged Higgs bosons at the LHC is the associated production with heavy quarks. We have calculated the next-to-leading-order supersymmetric QCD corrections to charged-Higgs production through the parton processes $q\bar{q},gg \to tbH^{\pm}$ and present results for total cross sections and differential distributions.

  29. Neal Jackson, Eran O. Ofek, Masamune Oguri

    We present observations of a new double-image gravitational lens system, ULAS J082016.1+081216, of image separation 2.3" and high (~6) flux ratio. The system is selected from the Sloan Digital Sky Survey spectroscopic quasar list using new high-quality images from the UKIRT Deep Sky Survey (UKIDSS). The lensed quasar has a source redshift of 2.024, and w

  30. Andrea Meucci, J. A. Caballero, C. Giusti, F. D. Pacati

    An analysis of inclusive quasielastic electron scattering is presented using different descriptions of the final state interactions within the framework of the relativistic impulse approximation. The relativistic Green's function approach is compared with calculations based on the use of relativistic purely real mean field potentials in the final state.

  31. O. C. de Jager, S. E. S. Ferreira, A. Djannati-Ataï, M. Dalton

    In this paper we explore the evolution of a PWN while the pulsar is spinning down. An MHD approach is used to simulate the evolution of a composite remnant. Particular attention is given to the adiabatic loss rate and evolution of the nebular field strength with time. By normalising a two component particle injection spectrum (which can reproduce the radio a

  32. David Goldberg, Freydoon Shahidi

    We continue our study of the poles of local Langlands L-functions through the theory of induced from supercuspidal representations of quasi-split groups. Here we study the odd special orthogonal groups, and hence determine poles of Rankin product L-functions. The pole of the intertwining operator is determined in terms of the theory of orbital integrals. Thi

  33. Masashige Matsumoto, Mikito Koga, Hiroaki Kusunose

    A single impurity problem is investigated for multiband s-wave superconductors with different sign order parameters (+-s-wave superconductors) suggested in Fe-pnictide superconductors. Not only intraband but also interband scattering is considered at the impurity. The latter gives rise to impurity-induced local boundstates close to the impurity. We present a

  34. Antonio Alarcon, Jose A. Galvez

    Let $Σ$ be a compact Riemann surface and $D_1,...,D_n$ a finite number of pairwise disjoint closed disks of $Σ$. We prove the existence of a proper harmonic map into the Euclidean plane from a hyperbolic domain $Ω$ containing $Σ\backslash\cup_{j=1}^n D_j$ and of its topological type. Here, $Ω$ can be chosen as close as necessary to $Σ\backslash\cup_{j=1}^n D

  35. Lars Sonnenschein

    Photon plus jet production has been studied by the D0 experiment in Run II of the Fermilab Tevatron Collider at a centre of mass energy of sqrt{s}=1.96 TeV. Measurements of the inclusive photon, inclusive photon plus jet, photon plus heavy flavour jet cross sections and double parton interactions in photon plus three jet events are presented. They are based

  36. Tomáš Vinař, Broňa Brejová, Giltae Song, Adam Siepel

    Clusters of genes that have evolved by repeated segmental duplication present difficult challenges throughout genomic analysis, from sequence assembly to functional analysis. Improved understanding of these clusters is of utmost importance, since they have been shown to be the source of evolutionary innovation, and have been linked to multiple diseases, incl

  37. A. C. Aguilar, D. Binosi, J. Papavassiliou, J. Rodriguez-Quintero

    We study the non-perturbative behavior of two versions of the QCD effective charge, one obtained from the pinch technique gluon self-energy, and one from the ghost-gluon vertex. Despite their distinct theoretical origin, due to a fundamental identity relating various of the ingredients appearing in their respective definitions, the two effective charges are

  38. Vladimir G. Ivanov, Evgeny Yu. Korzinin, Savely G. Karshenboim

    Non-relativisitic second-order corrections to the wave function at origin in muonic and exotic atoms are considered. The corrections are due to the electronic vacuum polarization. Such corrections are of interest due to various effective approaches, which take into account QED and hadronic effects. The wave function at origin plays a key role in the calculat

  39. Christian Wyss

    For p-subordinate perturbations of unbounded normal operators, the change of the spectrum is studied and spectral criteria for the existence of a Riesz basis with parentheses of root vectors are established. A Riesz basis without parentheses is obtained under an additional a priori assumption on the spectrum of the perturbed operator. The results are applied

  40. J. R. Dawson, N. M. McClure-Griffiths, Y. Fukui

    We present new parsec-scale resolution data from a multi-phase study of the ISM in the walls of Galactic supershells. HI synthesis images and CO survey data reveal a wealth of substructure, including dense-tipped fingers and extended molecular clouds embedded in shell walls. We briefly consider formation scenarios for these features, and suggest that both th

  41. Lhoussain El fadil, Jesus Montes, Enric Nart

    Let p be a prime number. In this paper we use an old technique of Ore, based on Newton polygons, to construct in an efficient way p-integral bases of number fields defined by a p-regular equation. To illustrate the potential applications of this construction, we show how this result yields a computation of a p-integral basis of an arbitrary quartic field in

  42. E. Poretti, E. Michel, R. Garrido, L. Lefevre

    It has also been suggested that the detection of a wealth of very low amplitude modes in Delta Sct stars was only a matter of signal--to--noise ratio. Access to this treasure, impossible from the ground, is one of the scientific aims of the space mission CoRoT, a space mission developed and operated by CNES. This work presents the results obtained on HD 5084

  43. E. Schachinger, J. P. Carbotte, T. Timusk

    There is an ongoing debate about the nature of the bosonic excitations responsible for the quasiparticle self energy in high temperature superconductors -- are they phonons or spin fluctuations? We present a careful analysis of the bosonic excitations as revealed by the `kink' feature at 70 meV in angle resolved photoemission data using Eliashberg theory

  44. W. Fenz, I. M. Mryglod, O. Prytula, R. Folk

    Correlation functions and transport coefficients of self-diffusion and shear viscosity of a binary Lennard-Jones mixture with components differing only in their particle mass are studied up to high values of the mass ratio $μ$, including the limiting case $μ=\infty$, for different mole fractions $x$. Within a large range of $x$ and $μ$ the product of the dif

  45. Aranya B Bhattacherjee

    We consider the dynamics of a movable mirror (cantilever) of a cavity coupled through radiation pressure to the light scattered from ultracold atoms in an optical lattice. Scattering from different atomic quantum states creates different quantum states of the scattered light, which can be distinguished by measurements of the displacement spectrum of the cant

  46. Hatem Hamrouni

    Let $G$ be a connected and simply connected two-step nilpotent Lie group and $Γ$ a lattice subgroup of $G$. In this note, we give a new multiplicity formula, according to the sense of Moore, of irreducible unitary representations involved in the decomposition of the quasi-regular representation ${\rm Ind}_Γ^G(1)$. Extending then the Abelian case.

  47. Chao-Guang Huang, Meng-Sen Ma

    It is shown that all torsion-free vacuum solutions of the model of dS gauge theory of gravity are the vacuum solutions of Einstein field equations with the same positive cosmological constant. Furthermore, for the gravitational theories with more general quadratic gravitational Lagrangian ($F^2+T^2$), the torsion-free vacuum solutions are also the vacuum sol

  48. V. V. Bludov, A. M. W. Glass, V. M. Kopytov, N. Ya. Medvedev

    We provide a list of (mainly unsolved) problems in ordered and orderable groups. These were originally compiled 10 years ago by the last two authors. New problems have been added to the list. Progress on some of these is noted and references provided. A few have been solved and their solutions are noted and referenced. We hope that this submission will act a

  49. Ferdinando Patat

    The nature of the progenitor system[s] of Type Ia Supernovae is still unclear. In this contribution I review the projects that have been undertaken to answer this question and the results they have led to. The conclusion is that, as of today, we have reasonable guesses but none of them has yet been proven by direct observations.

  50. A. Ya. Bekshaev, A. I. Karamoch, M. V. Vasnetsov, V. A. Pas'ko

    Holographic gratings with topological defects (branching of one or more fringes) are widely used for generating light beams with optical vortices (OV). This work presents an analysis of OV beams produced by binary computer-generated holograms enlightened by Gaussian beams centered at the fringe bifurcation point. Usually such beams are considered as analogs

  51. Kazuya Fujio, Toshifumi Futamase

    We investigate the appearance of the classical anisotropic universe from the no-boundary quantum state according to the prescription proposed by Hartle, Hawking and Hertog. Our model is homogeneous, anisotropic, closed universes with a minimally coupled scalar field and cosmological constant. We found that there are an ensemble of classical Lorentzian histor

  52. Carl Graham, Philippe Robert, Maaike Verloop

    The equilibrium distributions of a Markovian model describing the interaction of several classes of permanent connections in a network are analyzed. It has been introduced by Graham and Robert. For this model each of the connections has a self-adaptive behavior in that its transmission rate along its route depends on the level of congestion of the nodes on i

  53. Hyoung Joon Choi, Steven G. Louie, Marvin L. Cohen

    Superconducting properties of hypothetical simple hexagonal CaB2 are studied using the fully anisotropic Eliashberg formalism based on electronic and phononic structures and electron-phonon interactions which are obtained from ab initio pseudopotential density functional calculations. The superconducting transition temperature Tc, the superconducting energy

  54. P. Guptaroy, Tarun K. Garain, Goutam Sau, S. K. Biswas

    We have attempted to develop here tentatively a model for $J/Ψ$ production in p+p, d+Au, Cu + Cu and Au + Au collisions at RHIC energies on the basic ansatz that the results of nucleus-nucleus collisions could be arrived at from the nucleon-nucleon (p + p)-interactions with induction of some additional specific features of high energy nuclear collisions. Bas

  55. S. Ihnatsenka, I. V. Zozoulenko, G. Kirczenow

    We calculate the band structure and the conductance of periodic corrugated graphene nanoribbons within the framework of the tight-binding $p$-orbital model. We consider corrugated structures based on host ribbons with armchair and zigzag edges and three different types of corrugations (armchair edges, zigzag edges as well as a rectangular corrugation). We de

  56. S. Goriely, N. Chamel, J. M. Pearson

    We present a new Skyrme-Hartree-Fock-Bogoliubov nuclear-mass model in which the contact-pairing force is constructed from microscopic pairing gaps of symmetric nuclear matter and neutron matter calculated from realistic two- and three-body forces, with medium-polarization effects included. With the pairing being treated more realistically than in any of our

  57. Benoît Claudon

    In this note, we show that the cohomology groups of (virtually) nilpotent Kähler groups are naturally endowed with a mixed Hodge structure. These structures make the Hopf morphisms into mixed Hodge structures morphisms. We illustrate this fact with the study of known examples of non-abelian nilpotent Kähler groups.

  58. Andres Navas, Bert Wiest

    We study the topological space of left-orderings of the braid group, and its subspace of Nielsen-Thurston orderings. Our main result is that no Nielsen-Thurston ordering is isolated in the space of braid orderings. In the course of the proof, we classify the convex subgroups and calculate the Conradian soul for any Nielsen-Thurston ordering of B_n. We also p

  59. Rajiv Soundararajan, Sriram Vishwanath

    This paper considers a degraded Gaussian broadcast channel over which Gaussian sources are to be communicated. When the sources are independent, this paper shows that hybrid coding achieves the optimal distortion region, the same as that of separate source and channel coding. It also shows that uncoded transmission is not optimal for this setting. For correl

  60. Soo-Chang Rey, Sangmo T. Sohn, Michael A. Beasley, Young-Wook Lee

    We explore the age distribution of the globular cluster (GC) system of the nearby elliptical galaxy NGC 5128 using ultraviolet (UV) photometry from Galaxy Evolution Explorer (GALEX) observations, with UV - optical colors used as the age indicator. Most GCs in NGC 5128 follow the general trends of GCs in M31 and Milky Way in UV - optical color-color diagram,

  61. M. Andrecut

    Computational time reversal imaging can be used to locate the position of multiple scatterers in a known background medium. The current methods for computational time reversal imaging are based on the null subspace projection operator, obtained through the singular value decomposition of the frequency response matrix. Here, we discuss the image recovery prob

  62. A. K. Kamra, Devendraa Siingha, Vimlesh Pant

    Measurements of the small,intermediate, and large ion concentrations and the airearth current density along with simultaneous measurements of the concentration and size-distribution of aerosol particles in the size ranges 4.4 to 163 nm and 0.5 to 20 micrometer diameters are reported for a drifting snow period after the occurrence of a blizzard at a coastal s

  63. Shigeyuki Kondo

    It is known that the moduli space of plane quartic curves is birational to an arithmetic quotient of a 6-dimensional complex ball. In this paper, we shall show that there exists a 15-dimensional space of meromorphic automorphic forms on the complex ball which gives a birational embedding of the moduli space of plane quartics with level 2 structure into 14-di

  64. C. A. Bertulani, H. F. Lu, H. Sagawa

    The neutron and proton odd-even mass differences are studied with Hartree-Fock+BCS (HFBCS) calculations with Skyrme interactions and an isospin dependent contact pairing interaction, which is recently derived from a microscopic nucleon-nucleon interaction. To this end, we perform HFBCS calculations for even and odd semi-magic Tin and Lead isotopes together w

  65. H. Zhang, Y. Wang, F. Yuan, F. Ding

    The temperature of hot accretion flows around black holes is sufficiently high for the ignition of nuclear reactions. This is potentially an important nucleosynthesis mechanism in the universe. As the first step in studying this problem, we need to measure physical quantities such as density and temperature of the accretion flow. In usual studies of the hot

  66. W. Wang

    The hard X-ray source 4U 2206+54 is a peculiar high mass X-ray binary with a main-sequence donor star. Recent X-ray observations suggested that the compact object in 4U 2206+54 may be a neutron star. The X-ray emission comes from the accretion of stellar winds from the massive donor stars, and variability of luminosity may be due to the changes of its orbit

  67. O. J. Lee, V. S. Pribiag, P. M. Braganca, P. G. Gowtham

    We report on spin valve devices that incorporate both an out-of-plane polarizer (OPP) to quickly excite spin torque (ST) switching and an in-plane polarizer/analyzer (IPP). For pulses < 200 ps we observe reliable precessional switching due largely to ST from the OPP. Compared to a conventional spin valve, for a given current in the short pulse regime the add

  68. Xin-Bing Huang

    Two kinds of Yang-Mills fields are found upon the concepts of mass eigenstate and nonmass eigenstate. The Yang-Mills fields of the first kind were proposed by Yang and Mills, which couple to the mass eigenstates with the same rest mass, whose gauge bosons are massless. I find that there are second kind of Yang-Mills fields, which are constructed on a five-di

  69. Armen E. Allahverdyan, Karen Hovhannisyan, Guenter Mahler

    We study a refrigerator model which consists of two $n$-level systems interacting via a pulsed external field. Each system couples to its own thermal bath at temperatures $T_h$ and $T_c$, respectively ($θ\equiv T_c/T_h<1$). The refrigerator functions in two steps: thermally isolated interaction between the systems driven by the external field and isothermal

  70. Mitiyasu Miyasita, Katsuhiko Higuchi, Masahiko Higuchi

    We present an alternative scheme for calculating the unrestricted Hartree-Fock equation. The scheme is based on the variational method utilizing the sophisticated basis functions that include no adjustable parameters. The validity and accuracy of the present scheme are confirmed by actual calculations of the boron and neon atoms. It is shown that the present

  71. Elena Gubankova

    We derived the low energy effective action for the collective modes in asymmetric fermionic systems with attractive interaction. We obtained the phase diagram in terms of the chemical potentials. It features a stable gapless superfluidity with one Fermi surface on the BEC side of the resonance. Also we predict a sharp increase in outer core of a vortex, i.e.

  72. Sucharit Sarkar

    This is the author&#39;s PhD thesis, as submitted to the Princeton University. The results of this paper have already appeared in arXiv:math/0607777v4, arXiv:math/0607691 and arXiv:0901.2156.

  73. John A. Tomsick, Sylvain Chaty, Jerome Rodriguez, Roland Walter

    We report on 0.3-10 keV X-ray observations by the Chandra X-ray Observatory of the fields of 22 sources that were discovered as hard X-ray (20-100 keV) sources by the INTEGRAL satellite (IGR sources). The purpose of the Chandra observations is to localize the sources and to measure their soft X-ray spectra in order to determine the nature of the sources. We

  74. Jan-Oliver Fröhlich, Theodor Müller

    The recent paper &#34;Linear Connectivity Forces Large Complete Bipartite Minors&#34; by Boehme et al. relies on a structure theorem for graphs with no H-minor. The sketch provided of how to deduce this theorem from the work of Robertson and Seymour appears to be incomplete. To fill this gap, we modify the main proof of that paper to work with a mere restate

  75. G. Kramer, H. Spiesberger

    We have calculated the next-to-leading order cross sections for the inclusive production of D*-mesons in ep collisions at HERA for finite, although very small Q2. In this Q2-range, the same approximations as for photoproduction can be used. Our calculation is performed in the general-mass variable-flavour-number scheme. In this approach, large logarithms of

  76. Runyao Duan

    We study various super-activation effects in the following zero-error communication scenario: One sender wants to send classical or quantum information through a noisy quantum channel to one receiver with zero probability of error. First we show that there are quantum channels of which a single use is not able to transmit classical information perfectly yet

  77. Neil D. Christensen, Priscila de Aquino, Celine Degrande, Claude Duhr

    We describe a framework to develop, implement and validate any perturbative Lagrangian-based particle physics model for further theoretical, phenomenological and experimental studies. The starting point is FeynRules, a Mathematica package that allows to generate Feynman rules for any Lagrangian and then, through dedicated interfaces, automatically pass the c

  78. Sergey Krivonos, Olaf Lechtenfeld

    We perform an su(2) Hamiltonian reduction of the general su(2)-invariant action for a self-coupled (4,4,0) supermultiplet. As a result, we elegantly recover the N=4 supersymmetric mechanics with spin degrees of freedom which was recently constructed in arXiv:0812.4276. This observation underscores the exceptional role played by the ``root&#39;&#39; supermult

  79. Robert G. Endres, Ned S. Wingreen

    Many types of cells are able to accurately sense shallow gradients of chemicals across their diameters, allowing the cells to move towards or away from chemical sources. This chemotactic ability relies on the remarkable capacity of cells to infer gradients from particles randomly arriving at cell-surface receptors by diffusion. Whereas the physical limits of

  80. Laurent Schoeffel

    Standard parton distribution functions contain neither information on the correlations between partons nor on their transverse motion, then a vital knowledge about the three dimensional structure of the nucleon is lost. Hard exclusive processes, in particular DVCS, are essential reactions to go beyond this standard picture. In the following, we examine the m

  81. Laurent Schoeffel

    A large collection of results for the diffractive dissociation of virtual photons, $γ^{\star}p \to Xp$, have been obtained with the H1 and ZEUS detectors at HERA. Different experimental techniques have been used, by requiring a large rapidity gap between $X$ and the outgoing proton, by analysing the mass distribution, $M_X$, of the hadronic final state, as w

  82. Dmitri Diakonov

    These lectures contain an introduction to instantons, calorons and dyons of the Yang--Mills gauge theory. Since we are interested in the mechanism of confinement and of the deconfinement phase transition at some critical temperature, the Yang--Mills theory is formulated and studied at nonzero temperatures. We introduce ``calorons with a nontrivial holonomy''

  83. M. Cappi, F. Tombesi, S. Bianchi, M. Dadina

    There is growing evidence for the presence of blueshifted Fe K absorption lines in a number of radio-quiet AGNs and QSOs. These may be fundamental to probe flow dynamics near supermassive black holes. Here we aim at verifying and better characterising the existence of such Fe K absorption at ~8-10 keV in the luminous Seyfert 1 galaxy Mrk509, one of the most

  84. Simone Marzani, Jeffrey Forshaw, James Keates

    We study the effect of soft gluon resummation on the gaps-between-jets cross-section at the LHC. We review the theoretical framework that enables one to sum logarithms of the hard scale over the veto scale to all orders in perturbation theory. We then present a study of the phenomenological impact of Coulomb gluon contributions and super-leading logarithms o

  85. Kiryung Lee, Yoram Bresler

    We address the inverse problem that arises in compressed sensing of a low-rank matrix. Our approach is to pose the inverse problem as an approximation problem with a specified target rank of the solution. A simple search over the target rank then provides the minimum rank solution satisfying a prescribed data approximation bound. We propose an atomic decompo

  86. Estanislao Herscovich, Andrea Solotar

    The aim of this article is to compute the Hochschild and cyclic homology groups of Yang-Mills algebras, that have been defined by A. Connes and M. Dubois-Violette. We proceed here the study of these algebras that we have initiated in a previous article. The computation involves the use of a spectral sequence associated to the natural filtration on the envelo

  87. P. Giannozzi, S. Baroni, N. Bonini, M. Calandra

    Quantum ESPRESSO is an integrated suite of computer codes for electronic-structure calculations and materials modeling, based on density-functional theory, plane waves, and pseudopotentials (norm-conserving, ultrasoft, and projector-augmented wave). Quantum ESPRESSO stands for &#34;opEn Source Package for Research in Electronic Structure, Simulation, and Opt

  88. Anže Slosar, Shirley Ho, Martin White, Thibaut Louis

    We present the first simulation of the signature of baryonic acoustic oscillations (BAO) in Lyman alpha forest data containing 180,000 mock quasar sight-lines. We use eight large dark-matter only simulations onto which we paint the Lyman alpha field using the fluctuating Gunn-Peterson approximation. We argue that this approach should be sufficient for the me

  89. Anders S. Sorensen, Ehud Altman, Michael Gullans, J. V. Porto

    We analyze a technique for the preparation of low entropy many body states of atoms in optical lattices based on adiabatic passage. In particular, we show that this method allows preparation of strongly correlated states as stable highest energy states of Hamiltonians that have trivial ground states. As an example, we analyze the generation of antiferromagne

  90. Vaibhav S Gadre

    A natural generalization of interval exchange maps are linear involutions, first introduced by Danthony and Nogueira. Recurrent train tracks with a single switch provide a subclass of linear involutions. We call such linear involutions non-classical interval exchanges. They are related to measured foliations on orientable flat surfaces. Non-classical interva

  91. Marc-André Laverdière, Serguei A. Mokhov, Djamel Benredjem

    The functions standardized as part of ISO C 1999 and their addendums improved very little the security options from the previously available library. The largest flaw remained that no function asked for the buffer size of destination buffers for any function copying data into a user-supplied buffer. According to earlier research we performed, we know that er

  92. Xavier Guitart, Santiago Molina

    We prove that the abelian $K$-surfaces whose endomorphism algebra is a quaternion algebra are parametrized, up to isogeny, by the $K$-rational points of the quotient of certain Shimura curves by the group of their Atkin-Lehner involutions.

  93. Razieh Annabestani, Vahid Karimipour

    A quantum protocol for sharing an arbitrary two-qubit state between N parties is introduced. Any of the members, can retrieve the state, only with collaboration of the other parties. We will show that in terms of resources, i.e. the number of classical bits, the number of Bell pairs shared, and also the type of measurements, our protocol is more efficient. F

  94. Wade Naylor, S. Matsuki, Tomoaki Nishimura, Yoshiaki Kido

    Parametric photon creation via the dynamical Casimir effect (DCE) is evaluated numerically, in a three-dimensional rectangular resonant cavity bisected by a semiconductor diaphragm (SD), which is irradiated by a pulsed laser with frequency of GHz order. The aim of this paper is to determine some of the optimum conditions required to detect DCE photons releva

  95. Alberto Pepe, Matthew Mayernik, Christine L. Borgman, Herbert Van de Sompel

    In the process of scientific research, many information objects are generated, all of which may remain valuable indefinitely. However, artifacts such as instrument data and associated calibration information may have little value in isolation; their meaning is derived from their relationships to each other. Individual artifacts are best represented as compon

  96. M. P. Kharlamov

    The general integrability cases in the rigid-body dynamics are the solutions of Lagrange, Euler, Kovalevskaya, and Goryachev-Chaplygin. The first two can be included in Smale&#39;s scheme for studying the phase topology of natural systems with symmetries. We modify Smale&#39;s program to suit the most complicated last two cases with non-linear first integral

  97. Arpad Hegedus

    Recently a set of functional equations defining the anomalous dimensions of arbitrary local single trace operators in planar N=4 supersymmetric Yang-Mills theory has been conjectured. These functional equations take the form of a Y-system defined on a special shaped domain. This Y-system can be equivalently reformulated as a T-system defined on a &#34;T-shap

  98. Hefeng Wang, Lian-Ao Wu, Yu-xi Liu, Franco Nori

    We propose a quantum algorithm for finding eigenvalues of non-unitary matrices. We show how to construct, through interactions in a quantum system and projective measurements, a non-Hermitian or non-unitary matrix and obtain its eigenvalues and eigenvectors. This proposal combines ideas of frequent measurement, measured quantum Fourier transform, and quantum

  99. Palle E. T. Jorgensen, Erin P. J. Pearse

    A resistance network is a connected graph $(G,c)$. The conductance function $c_{xy}$ weights the edges, which are then interpreted as conductors of possibly varying strengths. The Dirichlet energy form $\mathcal E$ produces a Hilbert space structure (which we call the energy space ${\mathcal H}_{\mathcal E}$) on the space of functions of finite energy. We us

  100. Eduardo I. Guendelman, Idan Shilon, Giovanni Cantatore, Konstantin Zioutas

    We calculate the total cross section for the production of photons from the scattering of axions by a strong inhomogeneous magnetic field in the form of a 2D delta-function, a cylindrical step function and a 2D Gaussian distribution, which can be approximately produced by a solenoidal current. The theoretical result is used to estimate the axion-photon conve