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October 2010 arXiv papers — page 55

Showing 5,4015,500 of 6,460 papers

  1. Ahmet Kara, Thomas Schwentick, Thomas Zeume

    The paper proposes and studies temporal logics for attributed words, that is, data words with a (finite) set of (attribute,value)-pairs at each position. It considers a basic logic which is a semantical fragment of the logic $LTL^\downarrow_1$ of Demri and Lazic with operators for navigation into the future and the past. By reduction to the emptiness problem

  2. Carlo Ewerz, Konrad Schade

    We use the gauge/gravity correspondence to study the screening of a heavy quark-antiquark pair in various strongly coupled plasmas. Besides N=4 super Yang-Mills theory and the corresponding AdS_5 space we also study theories obtained as deformations of AdS_5, among them in particular a class of deformations solving supergravity equations of motion. We consid

  3. Rogério Riffel, Charles Bonatto, Roberto Cid Fernandes, Miriani G. Pastoriza

    We study how the spectral fitting of galaxies, in terms of light fractions derived in one spectral region translates into another region, by using results from evolutionary synthesis models. In particular, we examine propagation dependencies on Evolutionary Population Synthesis (EPS, {\sc grasil}, {\sc galev}, Maraston and {\sc galaxev}) models, age, metalli

  4. F. Marocco, R. L. Smart, H. R. A. Jones, B. Burningham

    We present parallaxes of 11 mid-to-late T dwarfs observed in the UKIRT Infrared Deep Sky Survey. We use these results to test the reliability of model predictions in magnitude-color space, determine a magnitude-spectral type calibration, and, estimate a bolometric luminosity and effective temperature range for the targets. We used observations from the UKIRT

  5. F. Romeo, R. Citro

    We analyze the charge and spin pumping in an interacting dot within the almost adiabatic limit. By using a non-equilibrium Green's function technique within the time-dependent slave boson approximation, we analyze the pumped current in terms of the dynamical constraints in the infinite-U regime. The results show the presence of parasitic pumping currents

  6. Gian Paolo Leonardi, Severine Rigot, Davide Vittone

    In the sub-Riemannian Heisenberg group equipped with its Carnot-Caratheodory metric and with a Haar measure, we consider isodiametric sets, i.e. sets maximizing the measure among all sets with a given diameter. In particular, given an isodiametric set, and up to negligible sets, we prove that its boundary is given by the graphs of two locally Lipschitz funct

  7. I. A. Nekrasov, E. E. Kokorina, V. A. ~Galkin, Y. I. Kuz'min

    In this paper we present theoretical investigation of optical conductivity for intermetallic TbNi_{5-x}Cu_x series. In the frame of LSDA+U calculations electronic structure for x=0,1,2 and on top of that optical conductivities were calculated. Disorder effects of Ni for Cu substitution on a level of LSDA+U densities of states (DOS) were taken into account vi

  8. Claire Amiot, Steffen Oppermann

    Cluster categories of hereditary algebras have been introduced as orbit categories of their derived categories. Keller has pointed out that for non-hereditary algebras orbit categories need not be triangulated, and he introduced the notion of triangulated hull to overcome this problem. In this paper we study the image if the natural functor from the bounded

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

    Mature neutron stars are expected to contain various kinds of superfluids in their interiors. Modeling such stars requires the knowledge of the mutual entrainment couplings between the different condensates. We present a unified equation of state describing the different regions of a neutron star with superfluid neutrons and superconducting protons in its co

  10. Harsh Singhal, George Michailidis

    We examine the problem of optimal design in the context of filtering multiple random walks. Specifically, we define the steady state E-optimal design criterion and show that the underlying optimization problem leads to a second order cone program. The developed methodology is applied to tracking network flow volumes using sampled data, where the design varia

  11. Igor A. Bandos

    We present the equations of motion for multiple M0-brane (mM0) system in an arbitrary curved supergravity superspace which generalizes the M(atrix) model equations for the case of arbitrary supergravity background. Although these were obtained in the frame of superembedding approach to mM0, we do not make a review of this approach in this contribution but co

  12. Farid Khalili, Stefan Danilishin, Helge Mueller-Ebhardt, Haixing Miao

    We consider enhancing the sensitivity of future gravitational-wave detectors by using double optical spring. When the power, detuning and bandwidth of the two carriers are chosen appropriately, the effect of the double optical spring can be described as a "negative inertia", which cancels the positive inertia of the test masses and thus increases the

  13. Joan J. Ferrando, Juan A. Sáez

    The algebraic study of the Bel-Robinson tensor proposed and initiated in a previous work (Gen. Relativ. Gravit. {\bf 41}, see ref [11]) is achieved. The canonical form of the different algebraic types is obtained in terms of Bel-Robinson eigen-tensors. An algorithmic determination of the Weyl tensor from the Bel-Robinson tensor is presented.

  14. F. E. Becerra, R. T. Willis, S. L. Rolston, H. J. Carmichael

    We investigate the transient response of the generated light from Four-Wave Mixing (FWM) in the diamond configuration using a step-down field excitation. The transients show fast decay times and oscillations that depend on the detunings and intensities of the fields. A simplified model taking into account the thermal motion of the atoms, propagation, absorpt

  15. Anirudh Pradhan, H. Amirhashchi, Bijan Saha

    New dark energy models in anisotropic Bianchi type-I (B-I) space-time with variable EoS parameter and constant deceleration parameter have been investigated in the present paper. The Einstein's field equations have been solved by applying a variation law for generalized Hubble's parameter in B-I space-time. The variation law for Hubble's paramete

  16. J. Jurcsik, B. Szeidl, C. Clement, Zs. Hurta

    The light curves of 50 RRab (RR0) stars in M5 collected in Paper I are investigated to detect Blazhko modulation. 18 Blazhko stars are identified, and modulation is suspected in two additional cases. The mean pulsation period of Blazhko stars is 0.04 d shorter than the mean period of the entire RRab sample in M5. Among the RRab stars with period shorter than

  17. B. Szafran, M. R. Poniedziałek

    We consider electron transport in a quantum wire with a side-coupled quantum ring in a two-dimensional model that accounts for a finite width of the channels. We use the finite difference technique to solve the scattering problem as well as to determine the ring-localized states of the energy continuum. The backscattering probability exhibits Fano peaks for

  18. Isaku Hasegawa, Hiroyuki Shima

    We investigate energetically favorable configurations of point disclinations in nematic films having a bump geometry. Gradual expansion in the bump width Δ gives rise to a sudden shift in the stable position of the disclinations from the top to the skirt of the bump. The positional shift observed across a threshold Δth obeys a power law function of |Δ-Δth|,

  19. B. Szeid, Zs. Hurta, J. Jurcsik, C. Clement

    The period changes of 86 M5 RR Lyrae stars have been investigated on a one-hundred-year time base. The published observations have been supplemented by archival Asiago, Konkoly and Las Campanas photographic observations obtained between 1952 and 1993. About two thirds of the O-C diagrams could be fitted by a straight line or a parabola. 21 RR Lyrae stars hav

  20. Heping Zhang, Wei Li

    The permanental polynomial of a graph $G$ is $π(G,x)\triangleq\mathrm{per}(xI-A(G))$. From the result that a bipartite graph $G$ admits an orientation $G^e$ such that every cycle is oddly oriented if and only if it contains no even subdivision of $K_{2,3}$, Yan and Zhang showed that the permanental polynomial of such a bipartite graph $G$ can be expressed as

  21. Leonid Barenboim, Shlomi Dolev, Rafail Ostrovsky

    We consider the problem of clock synchronization in a wireless setting where processors must power-down their radios in order to save energy. Energy efficiency is a central goal in wireless networks, especially if energy resources are severely limited. In the current setting, the problem is to synchronize clocks of $m$ processors that wake up in arbitrary ti

  22. C. Echeverría-Arrondo, J. Pérez-Conde, A. Ayuela

    For nanostructured materials, strain is of fundamental importance in stabilizing a specific crystallographic phase, modifying electronic properties, and in consequence their magnetism when it applies. Here we describe a magnetic shape memory alloy in which nanostructure confinement strain influences the crystallographic phase and the electronic and magnetic

  23. Bum-Hoon Lee, Chanyong Park, Sunyoung Shin

    We investigate a gravity solution containing the gravitational backreaction of the massive scalar field dual to the chiral condensate, which corresponds to $1/N_c$ correction. In general, condensation changes the vacuum structure, so the present dual geometry is appropriate to describe the chiral condensate vacuum in the gauge theory side. After constructing

  24. Cheolwoo Park, Felix Hernández-Campos, J. S. Marron, Kevin Jeffay

    In this paper we examine rigorously the evidence for dependence among data size, transfer rate and duration in Internet flows. We emphasize two statistical approaches for studying dependence, including Pearson's correlation coefficient and the extremal dependence analysis method. We apply these methods to large data sets of packet traces from three netwo

  25. Nicolas Ginoux, Georges Habib

    We give a new upper bound for the smallest eigenvalues of the Dirac operator on a Riemannian flow carrying transversal Killing spinors. We derive an estimate on Sasakian and on 3-dimensional manifolds and partially classify those satisfying the limiting case. Finally, we compare our estimate with a lower bound in terms of a natural tensor depending on the ei

  26. Florian Bauer

    We study the role of the cosmological constant (CC) as a component of dark energy (DE). It is argued that the cosmological term is in general unavoidable and it should not be ignored even when dynamical DE sources are considered. From the theoretical point of view quantum zero-point energy and phase transitions suggest a CC of large magnitude in contrast to

  27. J. A. Gracey

    The three dimensional Gribov-Zwanziger Lagrangian is analysed at one and two loops. Specifically, the two loop gap equation is evaluated and the Gribov mass is expressed in terms of the coupling constant. The one loop corrections to the propagators of all the fields are determined. It is shown that when the gap equation is satisfied the Faddeev-Popov ghost a

  28. Mofreh R. Zaghloul

    The problem of the calculation of equilibrium thermodynamic properties and the establishment of statistical-thermodynamically-consistent finite bound-state partition functions in nonideal multi-component plasma systems is revised within the chemical picture. The present exploration accompanied by the introduction of a generalized accurate formulation, in ter

  29. Alexey Pospelov

    We study the complexity of polynomial multiplication over arbitrary fields. We present a unified approach that generalizes all known asymptotically fastest algorithms for this problem. In particular, the well-known algorithm for multiplication of polynomials over fields supporting DFTs of large smooth orders, Schönhage-Strassen's algorithm over arbitrary

  30. Junbai Wang

    By integrating heterogeneous functional genomic datasets, we have developed a new framework for detecting combinatorial control of gene expression, which includes estimating transcription factor activities using a singular value decomposition method and reducing high-dimensional input gene space by considering genomic properties of gene clusters. The predict

  31. Junbai Wang, Leo Wang-Kit Cheung, Jan Delabie

    This paper introduces two new probabilistic graphical models for reconstruction of genetic regulatory networks using DNA microarray data. One is an Independence Graph (IG) model with either a forward or a backward search algorithm and the other one is a Gaussian Network (GN) model with a novel greedy search method. The performances of both models were evalua

  32. Mukul S. Laad, Luis Craco

    We consider the effects of the non-local Ising-like "core spin" correlations on the order-parameter fluctuation contribution to the resistivity and thermodynamics of metals showing Ising-like order at finite temperature. We employ the well-known cluster-variation method, and present explicit results in the pair approximation for short-range order. Ou

  33. H Hosseinkhani, M Modarres

    To overcome the complexity of generalized two hard scale ($k_t$,$μ$) evolution equation, well known as the $Ciafaloni$, $Catani$, $Fiorani$ and $Marchsini$ ($CCFM$) evolution equations, and calculate the unintegrated parton distribution functions ($UPDF$), $Kimber$, $Martin$ and $Ryskin$ ($KMR$) proposed a procedure based on ($i$) the inclusion of single-sca

  34. Bjoern Malte Schaefer, Angelos Fotios Kalovidouris, Lavinia Heisenberg

    The subject of this paper is an investigation of the nonlinear contributions to the spectrum of the integrated Sachs-Wolfe (iSW) effect. We derive the corrections to the iSW-auto spectrum and the iSW-tracer cross-spectrum consistently to third order in perturbation theory and analyse the cumulative signal-to-noise ratio for a cross-correlation between the PL

  35. A. N. Panov

    We study finite dimensional algebras that appear as fibers of quantum orders over a given point of variety of center. We present the formula for the number of irreducible representations and check it for it for the algebra of twisted polynomials, the quantum Weyl algebra and the algebra of regular functions on quantum group.

  36. K. P. Khemchandani, Eef van Beveren, George Rupp

    We study meson-meson scattering in a soluble model which describes asymptotically free mesons and confined quark-antiquark pairs via coupled channels. Concretely, the two scattered mesons are assumed to interact through s-channel meson-exchange diagrams. Furthermore, we develop a perturbative expansion of the model, and show that the thus found resonance pol

  37. Sergei V. Karpov, Ivan L. Isaev

    The effect of optical radiation on the rate of aggregation of nanoscopic particles is studied in metal aerosols. It has been shown that under light exposure, polydisperse metal aerosols can aggregate up to two orders faster due to the size dependent photoelectron effect from nanoparticles. Different size nanoparticles undergo mutual heteropolar charging when

  38. Keith A. Baggerly, Kevin R. Coombes

    High-throughput biological assays such as microarrays let us ask very detailed questions about how diseases operate, and promise to let us personalize therapy. Data processing, however, is often not described well enough to allow for exact reproduction of the results, leading to exercises in "forensic bioinformatics" where aspects of raw data and rep

  39. Matthias Degroote, Dimitri Van Neck, Carlo Barbieri

    The Faddeev Random Phase Approximation is a Green's function technique that makes use of Faddeev-equations to couple the motion of a single electron to the two-particle--one-hole and two-hole--one-particle excitations. This method goes beyond the frequently used third-order Algebraic Diagrammatic Construction method: all diagrams involving the exchange o

  40. S. Osone

    We design a GeV gamma ray detector based on an electron-positron pair measurement by using the BESS-polar magnet and study it with the GEANT4 simulation code. We consider an additional counter to select an electron-positron pair for which the energy loss by bremsstrahlung is less than 100 MeV against AMS. We obtain a significantly low detector efficiency of

  41. Claudia Weber, Shincy John, Nicolas Spethmann, Dieter Meschede

    We study cold inter-species collisions of Caesium and Rubidium in a strongly imbalanced system with single and few Cs atoms. Observation of the single atom fuorescence dynamics yields insight into light-induced loss mechanisms, while both subsystems can remain in steady-state. This significantly simplifies the analysis of the dynamics, as Cs-Cs collisions ar

  42. Olivier Bodini, Thomas Fernique, Damien Regnault

    This paper introduces a simple Markov process inspired by the problem of quasicrystal growth. It acts over two-letter words by randomly performing \emph{flips}, a local transformation which exchanges two consecutive different letters. More precisely, only the flips which do not increase the number of pairs of consecutive identical letters are allowed. Fixed-

  43. Rafael López, Marian Ioan Munteanu

    In the homogeneous space Sol$_3$, a translation surface is parameterized by $x(s,t)=α(s)\astβ(t)$, where $α$ and $β$ are curves contained in coordinate planes and $\ast$ denotes the group operation of Sol$_3$. In this paper we study translation surfaces in Sol$_3$ whose mean curvature vanishes.

  44. François Dahmani, Vincent Guirardel

    Consider a relatively hyperbolic group G. We prove that if G is finitely presented, so are its parabolic subgroups. Moreover, a presentation of the parabolic subgroups can be found algorithmically from a presentation of G, a solution of its word problem, and generating sets of the parabolic subgroups. We also give an algorithm that finds parabolic subgroups

  45. Olivier Chesneau

    The recent high angular resolution observations have shown that the transition between a globally symmetrical giant and a source surrounded by a spatially complex environment occurs relatively early, as soon as the external layers of the stars are not tightly bound to the core of the star anymore. In this review, the emphasis will be put on the delineating t

  46. James E. Owen, Barbara Ercolano, Cathie J. Clarke

    We have performed hydrodynamic and radiative transfer calculations of a photoevaporating disc around a Herbig Ae/Be star to determine the evolution and observational impact of dust entrained in the wind. We find that the wind selectively entrains grains of different sizes at different radii resulting in a dust population that varies spatially and increases w

  47. Tristan Guillot, Mathieu Havel

    Context: CoRoT-2b is one of the most anomalously large exoplanet known. Given its large mass, its large radius cannot be explained by standard evolution models. Interestingly, the planet's parent star is an active, rapidly rotating solar-like star with a large fraction (7 to 20%) of spots. Aims: We want to provide constraints on the properties of the sta

  48. S. Paudel, T. Lisker, J. Janz

    To address the question of whether the so-called ultra compact dwarf galaxies (UCDs) are the remnant nuclei of destroyed early-type dwarf galaxies (dEs), we analyze the stellar population parameters of the nuclei of 34 Virgo dEs, as well as ten Virgo UCDs, including one that we discovered and which we report on here. Based on absorption line strength (Lick i

  49. Masashi Yasunaga, Makoto Tsubota

    We used the Gross--Pitaevskii equations to investigate ferromagnetic resonance in spin-1 Bose--Einstein condensates with a magnetic dipole-dipole interaction. By introducing the dipole interaction, we obtained equations similar to the Kittel equations used to represent ferromagnetic resonance in condensed matter physics. These equations indicated that the fe

  50. Otakar Frank, Georgia Tsoukleri, Ibtsam Riaz, Konstantinos Papagelis

    Carbon fibres (CF) represent a significant volume fraction of modern structural airframes. Embedded into polymer matrices, they provide significant strength and stiffness gains over unit weight as compared to other competing structural materials. Nevertheless, no conclusive structural model yet exists to account for their extraordinary properties. In particu

  51. Raj Kumar, Raj K Gupta

    we use the nuclear proximity potential obtained recently for the Skyrme nucleus-nucleus interaction in the semiclassical extended Thomas Fermi (ETF) approach using Skyrme energy density formalism (SEDF) under frozen-density (sudden-without-exchange) approximation, and $Φ$=0$^0$. This method allows the barrier modifications by using different Skyrme forces, s

  52. Charles L. H. Hull, Geoffrey C. Bower, Steve Croft, Peter K. G. Williams

    Image quality in mosaicked observations from interferometric radio telescopes is strongly dependent on the accuracy with which the antenna primary beam is calibrated. The next generation of radio telescope arrays such as the Allen Telescope Array (ATA) and the Square Kilometer Array (SKA) have key science goals that involve making large mosaicked observation

  53. Ian M. Aberbach, Aline Hosry

    The Briançon-Skoda theorem in its many versions has been studied by algebraists for several decades. In this paper, under some assumptions on an F-rational local ring $(R,\m)$, and an ideal $I$ of $R$ of analytic spread $\ell$ and height $g < \ell$, we improve on two theorems by Aberbach and Huneke. Let $J$ be a reduction of $I$. We first give results on whe

  54. Karo Michaelian

    The homochirality of the molecules of life has been a vexing problem with no generally accepted solution to date. Since a racemic mixture of chiral nucleotides frustrates the extension and replication of RNA and DNA, understanding the origin of homochirality has important implications to the investigation of the origin of life. Here we suggest a novel soluti

  55. T. Jinno, T. Mori, T. Ohshima, Y. Arita

    In order to develop a long-lifetime MCP-PMT under high rates of circumstance, we investigated the degradation of the quantum efficiency (QE) of PMT&#39;s with a multialkali photocathode. We found that not only positive ions, but also neutral residual gases would damage the photocathode resulting in an enhancement of the work function; their countermeasures w

  56. John M. Neuberger, Nandor Sieben, James W. Swift

    We apply the Gradient-Newton-Galerkin-Algorithm (GNGA) of Neuberger & Swift to find solutions to a semilinear elliptic Dirichlet problem on the region whose boundary is the Koch snowflake. In a recent paper, we described an accurate and efficient method for generating a basis of eigenfunctions of the Laplacian on this region. In that work, we used the symmet

  57. J. -W. He, B. Torrecillas, F. Van Oystaeyen, Y. Zhang

    A duality theorem of the bounded derived category of quasi-finite comodules over an artinian coalgebra is established. Let $A$ be a noetherian complete basic semiperfect algebra over an algebraically closed field, and $C$ be its dual coalgebra. If $A$ is Artin-Schelter regular, then the local cohomology of $A$ is isomorphic to a shift of twisted bimodule ${}

  58. Peiliang Xu, Elizabeth Cannon, Gerard Lachapelle

    This arXiv upload is to clarify that the now well-known sorted QR MIMO decoder was first presented in the 1995 IUGG General Assembly. We clearly go much further in the sense that we directly incorporated reduction into this one step, non-exact suboptimal integer solution. Except for these first few lines up to this point, this paper is an unaltered version o

  59. Sanghyuk Kim, Soojong Pak, Seunghyuk Chang, Geon Hee Kim

    We develop a proto-model of an off-axis reflective telescope for infrared wide-field observations based on the design of Schwarzschild-Chang type telescope. With only two mirrors, this design achieves an entrance pupil diameter of 50 mm and an effective focal length of 100 mm. We can apply this design to a mid-infrared telescope with a field of view of 8 deg

  60. Yuao Hu

    We consider heteroscedastic nonparametric regression models, when both the mean function and variance function are unknown and to be estimated with nonparametric approaches. We derive convergence rates of posterior distributions for this model with different priors, including splines and Gaussian process priors. The results are based on the general ones on t

  61. Anand Louis

    We give O(log^2 n)-approximation algorithm based on the cut-matching framework of [10, 13, 14] for computing the sparsest cut on directed graphs. Our algorithm uses only O(log^2 n) single commodity max-flow computations and thus breaks the multicommodity-flow barrier for computing the sparsest cut on directed graphs

  62. Jeroen Hazewinkel, Leo R. M. Maas, Stuart B. Dalziel

    This paper gives background information for the fluid dynamics video on internal wave motion in a trapezoidal tank.

  63. Esteban Andruchow, Gabriel Larotonda

    Let A be a von Neumann algebra with a finite trace $τ$, represented in $H=L^2(A,τ)$, and let $B_t\subset A$ be sub-algebras, for $t$ in an interval $I$. Let $E_t:A\to B_t$ be the unique $τ$-preserving conditional expectation. We say that the path $t\mapsto E_t$ is smooth if for every $a\in A$ and $v \in H$, the map $$ I\ni t\mapsto E_t(a)v\in H $$ is continu

  64. Rodrigo Treviño

    We prove the non-uniform hyperbolicity of the Kontsevich-Zorich cocycle for a measure supported on abelian differentials which come from non-orientable quadratic differentials through a standard orientating, double cover construction. The proof uses Forni's criterion for non-uniform hyperbolicity of the cocycle for SL(2,R)-invariant measures. We apply these

  65. Victor Chua, Hong Yao, Gregory A. Fiete

    We study an exactly solvable quantum spin model of Kitaev type on the kagome lattice. We find a rich phase diagram which includes a topological (gapped) chiral spin liquid with gapless chiral edge states, and a gapless chiral spin liquid phase with a spin Fermi surface. The ground state of the current model contains an odd number of electrons per unit cell w

  66. Nuno Cardoso, Marco Cardoso, Pedro Bicudo

    The colour fields, created by a static gluon-quark-antiquark system, are computed in quenched SU(3) lattice QCD, in a $24^3\times 48$ lattice at $β=6.2$ and $a=0.07261(85)\,fm$. We study two geometries, one with a U shape and another with an L shape. The particular cases of the two gluon glueball and quark-antiquark are also studied, and the Casimir scaling

  67. Nicolai T A Haydn, Yannis Psiloyenis

    In this paper we prove two results. First we show that dynamical systems with a $ϕ$-mixing measure have in the limit Poisson distributed return times almost everywhere. We use the Chen-Stein method to also obtain rates of convergence. Our theorem improves on previous results by allowing for infinite partitions and dropping the requirement that the invariant

  68. Todd C. Hillwig

    A number of efforts are underway to detect close binary stars in planetary nebulae. The primary goal of these studies is to determine the binary fraction of central stars. The next stage is a detailed analysis of the binaries to determine physical parameters for the systems. These analyses can be combined with population synthesis models, common envelope evo

  69. Aldo L. Cotrone, Anatoly Dymarsky, Stanislav Kuperstein

    We study probe flavor branes supersymmetrically embedded in the Klebanov-Strassler background. The embedding is controlled by a single complex parameter mu related to the quark mass. We study the spectrum of the vector mesons as a function of mu and compare it with the experimental data. Assuming that the rho(2150) meson is a 3S mode we find a remarkable agr

  70. Brett Hern, Krishna Narayanan

    We investigate techniques for designing modulation/coding schemes for the wireless two-way relaying channel. The relay is assumed to have perfect channel state information, but the transmitters are assumed to have no channel state information. We consider physical layer network coding based on multilevel coding techniques. Our multilevel coding framework is

  71. James F. Steiner, Rubens C. Reis, Jeffrey E. McClintock, Ramesh Narayan

    We measure the spin of XTE J1550-564 in two ways: by modelling the thermal continuum spectrum of the accretion disc, and independently by modeling the broad red wing of the reflection fluorescence Fe-K line. We find that the spin measurements conducted independently using both leading methods are in agreement with one another. For the continuum-fitting analy

  72. Dubi Kelmer, Lior Silberman

    Let $G$ be $\SO(n,1)$ or $\SU(n,1)$ and let $Γ\subset G$ denote an arithmetic lattice. The hyperbolic manifold $Γ\backslash \calH$ comes with a natural family of covers, coming from the congruence subgroups of $Γ$. In many applications, it is useful to have a bound for the spectral gap that is uniform for this family. When $Γ$ is itself a congruence lattice,

  73. C. Tortora, N. R. Napolitano, V. F. Cardone, M. Capaccioli

    We discuss the colour, age and metallicity gradients in a wide sample of local SDSS early- and late-type galaxies. From the fitting of stellar population models we find that metallicity is the main driver of colour gradients and the age in the central regions is a dominant parameter which rules the scatter in both metallicity and age gradients. We find a con

  74. James Newling, Melvin Varughese, Bruce A. Bassett, Heather Campbell

    Future photometric supernova surveys will produce vastly more candidates than can be followed up spectroscopically, highlighting the need for effective classification methods based on lightcurves alone. Here we introduce boosting and kernel density estimation techniques which have minimal astrophysical input, and compare their performance on 20,000 simulated

  75. C. B. Brook, F. Governato, R. Roskar, G. Stinson

    Using high resolution, fully cosmological smoothed particle hydro-dynamical simulations of dwarf galaxies in a Lambda cold dark matter Universe, we show how baryons attain a final angular momentum distribution which allows pure disc galaxies to form. Blowing out substantial amounts of gas through supernovae and stellar winds, which is well supported observat

  76. Hsiao-Wen Chen, Daniel A. Perley, Christine D. Wilson, S. Bradley Cenko

    We report the discovery of the host galaxy of dark burst GRB080607 at z_GRB=3.036. GRB080607 is a unique case of a highly extinguished (A_V~3 mag) afterglow that was yet sufficiently bright for high-quality absorption-line spectroscopy. The host galaxy is clearly resolved in deep HST WF3/IR F160W images and well detected in the Spitzer IRAC 3.5 micron and 4.

  77. Tim Johannsen, Dimitrios Psaltis

    According to the no-hair theorem, astrophysical black holes are uniquely described by their masses and spins. An observational test of the no-hair theorem can be performed by measuring at least three different multipole moments of the spacetime of a black hole and verifying whether their values are consistent with the unique combinations of the Kerr solution

  78. Yulia Kuznetsova

    Let G be a locally compact group, and let U be its unitary representation on a Hilbert space H. Endow the space L(H) of linear bounded operators on H with weak operator topology. We prove that if U is a measurable map from G to L(H) then it is continuous. This result was known before for separable H. To prove this, we generalize a known theorem on nonmeasura

  79. Yashar D. Hezaveh, Gilbert P. Holder

    We study the effects of strong lensing on the observed number counts of mm sources using a ray tracing simulation and two number count models of unlensed sources. We employ a quantitative treatment of maximum attainable magnification factor depending on the physical size of the sources, also accounting for effects of lens halo ellipticity. We calculate predi

  80. Athena Stacy, Volker Bromm, Abraham Loeb

    We estimate the rotation speed of Population III (Pop III) stars within a minihalo at z ~ 20 using a smoothed particle hydrodynamics (SPH) simulation, beginning from cosmological initial conditions. We follow the evolution of the primordial gas up to densities of 10^12 cm^-3. Representing the growing hydrostatic cores with accreting sink particles, we measur

  81. F. T. Hioe, David Kuebel

    Some features of a parametrized space of orbits in the Schwarzschild geometry are described.

  82. M. A. Dantas, J. S. Alcaniz, D. Mania, Bharat Ratra

    The absence of guidance from fundamental physics about the mechanism behind cosmic acceleration has given rise to a number of alternative cosmological scenarios. These are based either on modifications of general relativistic gravitation theory on large scales or on the existence of new fields in Nature. In this paper we investigate the observational viabili

  83. Matthias Ihl, Marcus A. C. Torres, Henrique Boschi-Filho, C. A. Ballon Bayona

    Recently, Dymarsky, Kuperstein and Sonnenschein constructed an embedding of flavor D7- and anti-D7-branes in the Klebanov-Strassler geometry that breaks the supersymmetry of the background, yet is stable. In this article, we study in detail the spectrum of vector mesons in this new model of flavor chiral symmetry breaking and commence an analytical analysis

  84. Vestislav Apostolov, David M. J. Calderbank, Paul Gauduchon

    We give an explicit local classification of conformally equivalent but oppositely oriented Kaehler metrics on a 4-manifold which are toric with respect to a common 2-torus action. In the generic case, these structures have an intriguing local geometry depending on a quadratic polynomial and two arbitrary functions of one variable, these two functions being e

  85. D. M. Webber, V. Tishchenko, Q. ~Peng, S. Battu

    We report a measurement of the positive muon lifetime to a precision of 1.0 parts per million (ppm); it is the most precise particle lifetime ever measured. The experiment used a time-structured, low-energy muon beam and a segmented plastic scintillator array to record more than 2 x 10^{12} decays. Two different stopping target configurations were employed i

  86. C. -C. Lee, G. Acosta, J. S. Bunch, T. R. Schibli

    Pulses as short as 260 fs have been generated in a diode-pumped low-gain Er:Yb:glass laser by exploiting the nonlinear optical response of single-layer graphene. The application of this novel material to solid-state bulk lasers opens up a way to compact and robust lasers with ultrahigh repetition rates.

  87. The BABAR Collaboration, P. del Amo Sanchez etal

    We report the results of a study of the exclusive charmless semileptonic decays, $B^{+} \rightarrow η^{(\prime)} \ell^{+} ν$ and $B^{0} \rightarrow π^{-} \ell^{+} ν$, undertaken with approximately 464 million $\ensuremath{B\kern 0.18em\bar{\kern -0.18em B}}$ pairs collected at the $Υ(4S)$ resonance with the ${{\slshape B\kern-0.1em{\smaller A}\kern-0.1em B\k

  88. Markus J. Aschwanden

    The observed powerlaw distributions of solar flare parameters can be interpreted in terms of a nonlinear dissipative system in the state of self-organized criticality (SOC). We present a universal analytical model of a SOC process that is governed by three conditions: (i) a multiplicative or exponential growth phase, (ii) a randomly interrupted termination o

  89. Damien Calaque, Andrei Caldararu, Junwu Tu

    Let h \subset g be an inclusion of Lie algebras with quotient h-module n. There is a natural degree filtration on the h-module U(g)/U(g)h whose associated graded h-module is isomorphic to S(n). We give a necessary and sufficient condition for the existence of a splitting of this filtration. In turn such a splitting yields an isomorphism between the h-modules

  90. Saurabh Maiti, Andrey V. Chubukov

    We perform an analytical renormalization group (RG) study to address the role of Coulomb repulsion, the competition between extended s-wave superconducting order (s+-) and the spin-density wave (SDW) order and the angular dependence of the superconducting gap in multi-pocket models of Iron based superconductors. Previous analytic RG studies considered a toy

  91. Russ Thompson

    We use subgroup distortion to determine the rate of escape of a simple random walk on a class of polycyclic groups, and we show that the rate of escape is invariant under changes of generating set for these groups. For metabelian groups, we define a stronger form of subgroup distortion, which applies to non-finitely generated subgroups. Under this hypothesis

  92. Alexander Polishchuk, Leonid Positselski

    We define and study the Hochschild (co)homology of the second kind (known also as the Borel-Moore Hochschild homology and the compactly supported Hochschild cohomology) for curved DG-categories. An isomorphism between the Hochschild (co)homology of the second kind of a CDG-category B and the same of the DG-category C of right CDG-modules over B, projective a

  93. Murad Alim, Michael Hecht, Hans Jockers, Peter Mayr

    We present a detailed study of D-brane superpotentials depending on several open and closed-string deformations. The relative cohomology group associated with the brane defines a generalized hypergeometric GKZ system which determines the off-shell superpotential and its analytic properties under deformation. Explicit expressions for the N=1 superpotential fo

  94. Madhu Thalakulam, C. B. Simmons, B. J. Van Bael, B. M. Rosemeyer

    We investigate the tunnel rates and energies of excited states of small numbers of electrons in a quantum dot fabricated in a Si/SiGe heterostructure. Tunnel rates for loading and unloading electrons are found to be strongly energy dependent, and they vary significantly between different excited states. We show that this phenomenon enables charge sensing mea

  95. Jose R. Alonso

    Neutrino physics focuses on huge detectors deep underground. The Sanford Lab in South Dakota will build a 300 kiloton water-Cherenkov detector 1500 meters deep for muon neutrino oscillation studies of the mass hierarchy and CP violation. This will be used by the Long Baseline experiment (LBNE) detecting few GeV neutrinos from Fermilab, 1300 km away. The DAE{

  96. Giuliano Boava, Ruy Exel

    Recently, Cuntz and Li introduced the C^*-algebra A[R] associated to an integral domain R with finite quotients. In this paper, we show that A[R] is a partial group algebra of the group $K \rtimes K^x$ with suitable relations, where K is the field of fractions of R. We identify the spectrum of this relations and we show that it is homeomorphic to the profini

  97. Kai E. Wunderle, Rainer Dick

    We present the derivation of a supersymmetric model for fermionic fields with integer valued mass dimension based on a general superfield with one free spinor index. First, we demonstrate that it is impossible to formulate such a model based on a general scalar superfield. This is due to problems constructing a Lagrangian containing a kinetic term for the fe

  98. Tomohiro Harada, Masashi Kimura

    We derive a general formula for the center-of-mass (CM) energy for the near-horizon collision of two particles of the same rest mass on the equatorial plane around a Kerr black hole. We then apply this formula to a particle which plunges from the innermost stable circular orbit (ISCO) and collides with another particle near the horizon. It is found that the

  99. Klaus Thomsen

    It is shown that the crossed product of a unital AH-algebra with slow dimension growth by an endomorphism is purely infinite when it is simple, provided the endomorphism does not leave a trace state invariant and maps the unit to a full projection.

  100. Haizhong Li, Xianfeng Wang

    Let $x:M\to\mathbb{S}^{n+1}(1)$ be an n-dimensional compact hypersurface with constant scalar curvature $n(n-1)r,~r\geq 1$, in a unit sphere $\mathbb{S}^{n+1}(1),~n\geq 5$. We know that such hypersurfaces can be characterized as critical points for a variational problem of the integral $\int_MH dv$ of the mean curvature $H$. In this paper, we derive an optim