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December 2010 arXiv papers — page 29

Showing 2,8012,900 of 6,281 papers

  1. G. Anagnostopoulos, V. Rigas, E. Vassiliadis

    In this article we present examples of a wider study of space-time correlation of electron precipitation event of the Van Allen belts with the position and time of occurrence of strong (M>6.5) earthquakes. The study is based on the analysis of observations of electron bursts (EBs) with energies 70 - 2350 keV at middle geographic latitudes, which were detecte

  2. J. -S. Caux, J. Mossel

    We discuss the notion of integrability in quantum mechanics. Starting from a review of some definitions commonly used in the literature, we propose a different set of criteria, leading to a classification of models in terms of different integrability classes. We end by highlighting some of the expected physical properties associated to models fulfilling the

  3. Yoshikazu Tanaka, Noriki Terada, Taro Nakajima, Taro Kojima

    CuFeO_2 is one of the multiferroic materials and is the first case that the electric polarization is not explained by the magnetostriction model or the spin-current model. We have studied this material using soft x-ray resonant diffraction and found that superlattice reflection 0, 1 - 2q, 0 appears in the ferroelectric and incommensurate magnetic ordered pha

  4. G. Anagnostopoulos, A. Papandreou, P. Antoniou

    This paper brings space weather prediction close to earthquake (EQ) prediction research. The results of this paper support conclusions of previously presented statistical studies that solar activity influences the seismic activity, this influence is mediated through rapid geomagnetic disturbances and the geomagnetic disturbances are related with increases of

  5. Matthias W. Seeger, Hannes Nickisch

    We propose a novel algorithm to solve the expectation propagation relaxation of Bayesian inference for continuous-variable graphical models. In contrast to most previous algorithms, our method is provably convergent. By marrying convergent EP ideas from (Opper&Winther 05) with covariance decoupling techniques (Wipf&Nagarajan 08, Nickisch&Seeger 09), it runs

  6. Francesca Tria, Animesh Mukherjee, Andrea Baronchelli, Andrea Puglisi

    The Category Game is a multi-agent model that accounts for the emergence of shared categorization patterns in a population of interacting individuals. In the framework of the model, linguistic categories appear as long lived consensus states that are constantly reshaped and re-negotiated by the communicating individuals. It is therefore crucial to investigat

  7. Laura Desideri

    We apply Garnier's method to solve the Plateau problem for maximal surfaces in Minkowski 3-space. Our study relies on the improved version we gave of R. Garnier's resolution of the Plateau problem for polygonal boundary curves in Euclidean 3-space. Since in Minkowski space the method does not allow us to avoid the existence of singularities, the appr

  8. Rebecca N. Palmer, Jiannis K. Pachos

    We consider the bosonic fractional quantum Hall effect in the presence of a non-Abelian gauge field in addition to the usual Abelian magnetic field. The non-Abelian field breaks the twofold internal state degeneracy, but preserves the Landau level degeneracy. Using exact diagonalization, we find that for moderate non-Abelian field strengths the system's

  9. R. S. Schmidt, A. J. Bell, E. Castro, R. Hall-Wilton

    The Beam Conditions and Radiation Monitoring System, BRM, is implemented in CMS to protect the detector and provide an interface to the LHC. Seven sub-systems monitor beam conditions and the radiation level inside the detector on different time scales. They detect adverse beam conditions, facilitate beam tuning close to CMS, and measure the doses accumulated

  10. Dmitry Khlopin

    The extension of a conflict control problem with infinite horizon is constructed. This extension is the projective limit of restricted games. Relations between "sensitivity to target set" and the existence of the optimal control are studied. Special attention is paid to the pursuit-evasion game with "joint control/relaxed control".

  11. Z. Osmanov

    For active galactic nuclei (AGNs) we study the role of the mechanism of quasi-linear diffusion (QLD) in producing the high energy emission in the MeV-GeV domains strongly connected with the submillimeter/infrared radiation. Considering the kinetic equation governing the stationary regime of the QLD we investigate the feedback of the diffusion on electrons. W

  12. M. Marthaler, J. Leppäkangas, J. H. Cole

    We study a superconducting single-electron transistor (SSET) which is coupled to a LC-oscillator via the phase difference across one of the Josephson junctions. This leads to a strongly anharmonic coupling between the SSET and the oscillator. The coupling can oscillate with the number of photons which makes this system very similar to the single-atom injecti

  13. Paul Wenk, Stefan Kettemann

    The spin dynamics and spin relaxation of itinerant electrons in quantum wires with spin-orbit coupling is reviewed. We give an introduction to spin dynamics, and review spin-orbit coupling mechanisms in semiconductors. The spin diffusion equation with spin-orbit coupling is derived, using only intuitive, classical random walk arguments. We give an overview o

  14. Roman Ya. Kezerashvili, Justin F. Vazquez-Poritz

    We consider a special relativistic effect, known as the Poynting-Robertson effect, on various types of trajectories of solar sails. Since this effect occurs at order $v^ϕ/c$, where $v^ϕ$ is the tangential speed relative to the sun, it can dominate over other special relativistic effects, which occur at order $v^2/c^2$. While solar radiation can be used to pr

  15. V. Lubicz, F. Mescia, L. Orifici, S. Simula

    We investigate the vector and scalar form factors relevant for K_{\ell 3} semileptonic decays using maximally twisted-mass fermions with two flavors of dynamical quarks (N_f = 2). The simulations cover pion masses as light as 260 MeV and four values of the lattice spacing, ranging from ~0.05 up to ~0.1 fm, which allow to compute directly, for the first time,

  16. Zhaoshun Gao, Xianping Zhang, Dongliang Wang, Yanpeng Qi

    We fabricated the c axis and ab-plane biaxially aligned Sr0.6K0.4Fe2As2 superconductor using a two-step magnetic field procedure. The effect of magnetic fields on the structure and superconducting properties of Sr0.6K0.4Fe2As2 has been investigated by using X-ray diffraction and magnetic measurements. The degree of orientation of the samples was about 0.39 f

  17. Robert Clancy

    We find new examples of compact Spin(7)-manifolds using a construction of Joyce. The essential ingredient in Joyce's construction is a Calabi-Yau 4-orbifold with particular singularities admitting an antiholomorphic involution, which fixes the singularities. We search the class of well-formed quasismooth hypersurfaces in weighted projective spaces for su

  18. G. Gopkumar, T. E. Girish

    The cumulative contribution of odd (Bo) and even (BE) parity zonal magnetic multipoles to the solar magnetic fields is calculated using spherical harmonic coefficients of the photospheric magnetic field for the years 1959-1985. The dominant parity of the solar magnetic field is shown to change from odd to even during every sunspot cycle. The association of v

  19. Veronika E. Hubeny

    We propose a new and simple method of estimating the radiation due to an accelerated quark in a strongly coupled medium, within the framework of the AdS/CFT correspondence. In particular, we offer a heuristic explanation of the collimated nature of synchrotron radiation produced by a circling quark, which was recently studied in Phys.Rev.D81 (2010) 126001. T

  20. Radha Kessar, Markus Linckelmann

    We show that for any block algebra B of a finite group over an algebraically closed field of prime characteristic the dimension of HH^n(B) is bounded by a function depending only on the nonnegative integer n and the defect of B. The proof uses in particular a theorem of Brauer and Feit which implies the result for n=0.

  21. M. Marthaler, Y. Utsumi, D. S. Golubev, A. Shnirman

    We study the photon generation in a transmission line oscillator coupled to a driven qubit in the presence of a dissipative electromagnetic environment. It has been demonstrated previously that a population inversion in the qubit may lead to a lasing state of the oscillator. Here we show that the circuit can also exhibit the effect of "lasing without inv

  22. M. Bridges, E. A. Heron, C. O'Dushlaine, R. Segurado

    There are many instances in genetics in which we wish to determine whether two candidate populations are distinguishable on the basis of their genetic structure. Examples include populations which are geographically separated, case--control studies and quality control (when participants in a study have been genotyped at different laboratories). This latter a

  23. Radha Kessar, Shigeo Koshitani, Markus Linckelmann

    Using the classification of finite simple groups we prove Alperin's weight conjecture and the character theoretic version of Broue's abelian defect group conjecture for 2-blocks of finite groups with an elementary abelian defect group of order 8.

  24. Lars Hofer, Dominik Scherer, Leonardo Vernazza

    The 2.5 sigma discrepancy between theory and experiment observed in the difference Delta ACP = ACP(B- --> pi0 K-) - ACP(Bb0 --> pi+ K-) can be explained by a new electroweak (EW) penguin amplitude. Motivated by this result, we have analyzed the purely isospin-violating decays B_s --> phi pi0 and B_s phi rho0, which are dominated by EW penguins. Our results e

  25. Michael A. Soloviev

    In this paper, we establish an analog of Wightman's reconstruction theorem for nonlocal quantum field theory with a fundamental length. In our setting, the Wightman generalized functions are defined on test functions analytic in a complex l-neighborhood of the real space and are localizable at scales large compared to l. The causality condition is formul

  26. Juan Jesus Donaire, Jose G. Llorente, Artur Nicolau

    We prove that the Hausdorff dimension of the set of points where a function in the Zygmund class in the euclidean space has bounded divided differences, is bigger or equal to 1. A similar result for functions in the Small Zygmund class is also proved and an example is constructed to show that these results are sharp.

  27. Yaakov S. Kupitz, Horst Martini, Micha A. Perles

    We give a tight upper bound on the polygonal diameter of the interior, resp. exterior, of a simple $n$-gon, $n \ge 3$, in the plane as a function of $n$, and describe an $n$-gon $(n \ge 3)$ for which both upper bounds (for the interior and the exterior) are attained \emph{simultaneously}.

  28. Abed Abedelfatah

    We prove constructively that for any finite-dimensional commu- tative ring R, every stably free module over R[X;X^{1}] of rank > dim R is free, i.e., R[X;X^{-1}] is (dimR)-Hermite.

  29. C. Hartnack, A. Sood, H. Oeschler, J. Aichelin

    Comparing K+ spectra at low transverse momenta for different symmetric collision systems at beam energies around 1 AGeV allows for a direct determination of both the strength of the K+ nucleus potential as well as of the K+N rescattering cross section in a hadronic environment. Other little known or unknown quantities which enter the K+ dynamics, like the pr

  30. Marco Gersabeck

    LHCb has started its charm physics programme using the data taken at the LHC. The first measurements of open charm production cross-sections for proton proton collisions at $\sqrt{s}=7 \tev$ are presented. The cross-sections of the \PDzero, $\PDstar^+$, \PDplus, and \PDsplus mesons are found to be in broad agreement with theory predictions. The prospects for

  31. Alexander Croy, Ulf Saalmann

    The coherent time evolution of electrons in double quantum dots induced by fast bias-voltage switches is studied theoretically. As it was shown experimentally, such driven double quantum dots are potential devices for controlled manipulation of charge qubits. By numerically solving a quantum master equation we obtain the energy- and time-resolved electron tr

  32. Michael A. Soloviev

    We investigate noncommutative deformations of quantum field theories for different star products, particularly emphasizing the locality properties and the regularity of the deformed fields. Using functional analysis methods, we describe the basic structural features of the vacuum expectation values of star-modified products of fields and field commutators. A

  33. J. A. Vaccaro

    We generalize Bohr's complementarity principle for wave and particle properties to arbitrary quantum systems. We begin by noting that a particle-like state is represented by a spatially-localized wave function and its narrow probability density is displaced by spatial translations. In contrast a wave-like state is represented by a spatially-delocalized w

  34. Ferdinand Peper, Laszlo B. Kish

    Noise-based logic, by utilizing its multidimensional logic hyperspace, has significant potential for low-power parallel operations in beyond-Moore-chips. However universal gates for Boolean logic thus far had to rely on either time averaging to distinguish signals from each other or, alternatively, on squeezed logic signals, where the logic-high was represen

  35. Colin Ingalls, Alexander Kuznetsov

    We consider the class of singular double coverings $X \to \PP^3$ ramified in the degeneration locus $D$ of a family of 2-dimensional quadrics. These are precisely the quartic double solids constructed by Artin and Mumford as examples of unirational but nonrational conic bundles. With such quartic surface $D$ one can associate an Enriques surface $S$ which is

  36. Grigori Rozenblum

    We consider Toeplitz operators in different Bergman type spaces, having radial symbols with variable sign. We show that if the symbol has compact support or decays rapidly, the eigenvalues of such operators cannot decay too fast, essentially faster than for a sign-definite symbol with the same kind. On the other hand, if the symbol decays not sufficiently ra

  37. Edmond Iancu

    I review the parton picture at strong coupling emerging from the gauge/gravity duality together with its consequences for the energy loss and momentum broadening of a heavy quark moving through a strongly coupled plasma.

  38. R. N. Karasev

    We prove a result about partitioning an absolute continuous measure in $\mathbb R^d$ into 2d equal parts by a system of cones with common vertex, where $d$ is an odd prime power. The proof is topological and based on the calculation of the equivariant Euler class of a certain vector bundle.

  39. Vadim Vereschagin

    Nonlinear integrable models with two spatial and one temporal variables: Kadomtsev-Petviashvili equation and two-dimensional Toda lattice are investigated on the subject of correct formulation for boundary problem that can be solved within the framework of the Inverse Scattering Problem method. It is shown that there exists a large set of integrable boundary

  40. Plamen Fiziev

    This rather technical paper presents some generalization of the results of recent publications \cite{Shirkov2010, DVPF2010, PFDV2010} where toy models of dimensional reduction of space-time were considered. Here we introduce and consider a specific type of multidimensional space-times with nontrivial topology and nontrivial Riemannian metric, which admit a r

  41. I. Yigitoglu, Dennis Bonatsos

    A solution of the Bohr Hamiltonian appropriate for triaxial shapes, involving a Davidson potential in beta and a steep harmonic oscillator in gamma, centered around gamma=30 degrees, is developed. Analytical expressions for spectra and B(E2) transition rates ranging from a triaxial vibrator to the rigid triaxial rotator are obtained and compared to experimen

  42. Toshikazu Miyashita

    For the simply connected compact exceptional Lie group $E_8$, we determine the structure of subgroup $(E_8)^{σ, σ'}$ of $E_8$ which is the intersection $(E_8)^σ\cap (E_8)^{σ'}$. Then the space $E_8/(E_8)^{σ, σ'}$ is the exceptional $\mathbb{Z}_2 \times \mathbb{Z}_2$- symmetric space of type EVIII-VIII-VIII, and that we give two involutions $σ, σ&

  43. Sanjib Sharma, Kathryn V Johnston, Steven R. Majewski, James Bullock

    The ubiquity of substructure in the stellar halo has already been demonstrated by the SDSS and 2MASS and future surveys promise to explore the halo in ever more detail. This paper examines what can be learnt from current and future photometric-databases using group-finding techniques. We compare groups recovered from a sample of M-giants from 2MASS with thos

  44. Toshikazu Miyashita

    For simply connected compact exceptional Lie groups $G = F_4, E_6$ and $E_7$, we consider two involutions $σ, γ$ and determine the group structure of subgroups $G^{σ,γ}$ of $G$ which are the intersection $G^σ\cap G^γ$ of the fixed points subgroups of $G^σ$ and $G^γ$. The motivation is as follows. In [1](see the References of this paper), we determine the gro

  45. Oliver Lorscheid

    Let $X$ be a curve over $\F_q$ with function field $F$. In this paper, we define a graph for each Hecke operator with fixed ramification. A priori, these graphs can be seen as a convenient language to organize formulas for the action of Hecke operators on automorphic forms. However, they will prove to be a powerful tool for explicit calculations and proofs o

  46. Oren Ofer, Amit Keren, Jess H. Brewer, Tianheng H. Han

    We present transverse field muon spin rotation/relaxation measurements on single crystals of the spin-1/2 kagome antiferromagnet Herbertsmithite. We find that the spins are more easily polarized when the field is perpendicular to the kagome plane. We demonstrate that the difference in magnetization between the different directions cannot be accounted for by

  47. BESIII Collaboration

    With a sample of (225.2\pm2.8)*10^{6} J/psi events registered in the BESIII detector, J/psi->gamma pi^+ pi^- eta' is studied using two eta' decay modes: eta'->pi^+ pi^- eta and eta' -> gamma rho^0. The X(1835), which was previously observed by BESII, is confirmed with a statistical significance that is larger than 20σ. In addition, in the pi^

  48. I. H. Stairs, M. J. Keith, Z. Arzoumanian, W. Becker

    The Australian Square Kilometre Array Pathfinder (ASKAP) is a 36-element array with a 30-square-degree field of view being built at the proposed SKA site in Western Australia. We are conducting a Design Study for pulsar observations with ASKAP, planning both timing and search observations. We provide an overview of the ASKAP telescope and an update on pulsar

  49. Widad Machmouchi

    We prove that q-ary sparse codes with small bias are self-correctable and locally testable. We generalize a result of Kaufman and Sudan that proves the local testability and correctability of binary sparse codes with small bias. We use properties of q-ary Krawtchouk polynomials and the McWilliams identity -that relates the weight distribution of a code to th

  50. Suzanne L. Hawley, John J. Bochanski, Andrew A. West

    We report on the analysis of ~22,000 M dwarfs using a statistical parallax method. This technique employs a maximum-likelihood formulation to simultaneously solve for the absolute magnitude, velocity ellipsoid parameters and reflex solar motion of a homogeneous stellar sample, and has previously been applied to Galactic RR Lyrae and Cepheid populations and t

  51. Xueliang Li, Yongtang Shi

    A vertex-colored graph is {\it rainbow vertex-connected} if any two vertices are connected by a path whose internal vertices have distinct colors, which was introduced by Krivelevich and Yuster. The {\it rainbow vertex-connection} of a connected graph $G$, denoted by $rvc(G)$, is the smallest number of colors that are needed in order to make $G$ rainbow vert

  52. M. S. Wheatland, K. D. Leka

    A nonlinear force-free solution is constructed for the coronal magnetic field in NOAA solar active region AR 10953 based on a photospheric vector magnetogram derived from Hinode satellite observations on 30 April 2007, taking into account uncertainties in the boundary data and using improved methods for merging multiple-instrument data. The solution demonstr

  53. Wolfgang Gatterbauer

    We develop an abstract model of information acquisition from redundant data. We assume a random sampling process from data which provide information with bias and are interested in the fraction of information we expect to learn as function of (i) the sampled fraction (recall) and (ii) varying bias of information (redundancy distributions). We develop two rul

  54. Er-Cheng Tsai

    It is known that the $γ_{5}$ scheme of Breitenlohner and Maison (BM) in dimensional regularization requires finite counter-term renormalization to restore gauge symmetry and implementing this finite renormalization in practical calculation is a daunting task even at 1-loop order. In this paper, we show that there is a simple and straightforward method to obt

  55. C. Espaillat, E. Furlan, P. D'Alessio, B. Sargent

    We present a Spitzer IRS study of variability in 14 T Tauri stars in the Taurus and Chamaeleon star-forming regions. The sample is composed of transitional and pre-transitional objects which contain holes and gaps in their disks. We detect variability between 5-38 microns in all but two of our objects on timescales of 2-3 years. Most of the variability obser

  56. K. Hagino, A. Vitturi, F. Perez-Bernal, H. Sagawa

    We propose a simple schematic model for two-neutron halo nuclei. In this model, the two valence neutrons move in a one-dimensional mean field, interacting with each other via a density-dependent contact interaction. We first investigate the ground state properties, and demonstrate that the dineutron correlation can be realized with this simple model due to t

  57. Daisuke Jido

    Recent theoretical developments of hadrons in nuclei are briefly reviewed in the aspect of chiral symmetry in nuclei. We show a general sum rule connecting in-medium hadronic quantities and quark condensate, emphasizing that both pionic mode and particle-hole excitations in the nuclear medium are responsible for reduction of the chiral condensate in nuclear

  58. F. Jonietz, S. Mühlbauer, C. Pfleiderer, A. Neubauer

    Spin manipulation using electric currents is one of the most promising directions in the field of spintronics. We used neutron scattering to observe the influence of an electric current on the magnetic structure in a bulk material. In the skyrmion lattice of MnSi, where the spins form a lattice of magnetic vortices similar to the vortex lattice in type II su

  59. Thomas Hangelbroek, Fran J Narcowich, Xingping Sun, Joe D Ward

    This article addresses two topics of significant mathematical and practical interest in the theory of kernel approximation: the existence of local and stable bases and the L_p--boundedness of the least squares operator. The latter is an analogue of the classical problem in univariate spline theory, known there as the "de Boor conjecture". A corollary

  60. Justin Farischon, Larry Zamick

    We have compiled some sections of works by L. Zamick and collaborators which we hope will be of interest to the reader.

  61. Jeffrey A. Appel

    The CHARM 2010 meeting had over 30 presentations of experimental results, plus additional future facilities talks just before this summary talk. Since there is not enough time even to summarize all that has been shown from experiments and to recognize all the memorable plots and results, this summary will give a few personal observations, an overview at a fa

  62. Valeri N. Kotov, Bruno Uchoa, Vitor M. Pereira, F. Guinea

    We review the problem of electron-electron interactions in graphene. Starting from the screening of long range interactions in these systems, we discuss the existence of an emerging Dirac liquid of Lorentz invariant quasi-particles in the weak coupling regime, and strongly correlated electronic states in the strong coupling regime. We also analyze the analog

  63. M. Jasperse, L. D. Turner, R. E. Scholten

    Four-wave mixing near resonance in an atomic vapor can produce relative intensity squeezed light suitable for precision measurements beyond the shot-noise limit. We develop an analytic distributed gain/loss model to describe the competition of mixing and absorption through the non-linear medium. Using a novel matrix calculus, we present closed-form expressio

  64. M. Hossein Partovi

    Heisenberg's uncertainty principle is formulated for a set of generalized measurements within the framework of majorization theory, resulting in a partial uncertainty order on probability vectors that is stronger than those based on quasi-entropic measures. The theorem that results from this formulation guarantees that the uncertainty of the results of a

  65. Rachel Kuzio de Naray, Tobias Kaufmann

    We present mock DensePak Integral Field Unit (IFU) velocity fields, rotation curves, and halo fits for disc galaxies formed in spherical and triaxial cuspy dark matter haloes, and spherical cored dark matter haloes. The simulated galaxies are "observed" under a variety of realistic conditions to determine how well the underlying dark matter halo can

  66. David G. Gilbank, M. D. Gladders, H. K. C. Yee, B. C. Hsieh

    The second Red-sequence Cluster Survey (RCS-2) is a ~1000 square degree, multi-color imaging survey using the square-degree imager, MegaCam, on the Canada-France-Hawaii Telescope (CFHT). It is designed to detect clusters of galaxies over the redshift range 0.1<~z<~1. The primary aim is to build a statistically complete, large (~10^4) sample of clusters, cove

  67. P. S. Corasaniti, I. Achitouv

    We compute the dark matter halo mass function using the excursion set formalism for a diffusive barrier with linearly drifting average which captures the main features of the ellipsoidal collapse model. We evaluate the non-Markovian corrections due to the sharp filtering of the linear density field in real space with a path-integral method. We find an unprec

  68. Luis A. Anchordoqui, Wan-Zhe Feng, Haim Goldberg, Xing Huang

    If the fundamental mass scale of superstring theory is as low as few TeVs, the massive modes of vibrating strings, Regge excitations, will be copiously produced at the Large Hadron Collider (LHC). We discuss the complementary signals of low mass superstrings at the proposed electron-positron facility (CLIC), in e^+e^- and γγcollisions. We examine all relevan

  69. A. V. Belitsky, Richard F. Lebed, Van E. Mayes

    We construct a four-generation MSSM with rank-4 Yukawa matrices from intersecting D6 branes on a T^6/(Z_2 x Z_2) orientifold. The Yukawa matrices obtained provide an example of Flavor Democracy (FD), where the Yukawa couplings are all nearly equal. Mass hierarchies may then be generated by slight perturbations away from FD. We find that it is possible to obt

  70. Bom Soo Kim, Elias Kiritsis, Christos Panagopoulos

    A holographic model of a quantum critical theory at a finite but low temperature, and finite density is studied. The model exhibits non-relativistic z=2 Schrödinger symmetry and is realized by the Anti-de-Sitter-Schwarzschild black hole in light-cone coordinates. Our approach addresses the electrical conductivities in the presence or absence of an applied ma

  71. R. Stoll, J. L. Prieto, K. Z. Stanek, R. W. Pogge

    We present ASAS data starting 25 days before the discovery of the recent type IIn SN 2010jl, and we compare its light curve to other luminous IIn SNe, showing that it is a luminous (M_I ~ -20.5) event. Its host galaxy, UGC 5189, has a low gas-phase oxygen abundance (12 + log(O/H) = 8.2), which reinforces the emerging trend that over-luminous core-collapse su

  72. Seshadri Nadathur, Subir Sarkar

    In the standard cosmological model, the dimming of distant Type Ia supernovae is explained by invoking the existence of repulsive `dark energy&#39; which is causing the Hubble expansion to accelerate. However this may be an artifact of interpreting the data in an (oversimplified) homogeneous model universe. In the simplest inhomogeneous model which fits the

  73. Dimitrie Culcer, S. Das Sarma

    The anomalous Hall effect due to the surface conduction band of 3D topological insulators with an out-of-plane magnetization is \textit{always} dominated by an intrinsic topological term of the order of the conductivity quantum. We determine the contributions due to the band structure, skew scattering, side jump and magnetic impurities on the same footing, d

  74. Miguel Pato, Laura Baudis, Gianfranco Bertone, Roberto Ruiz de Austri

    We investigate the reconstruction capabilities of Dark Matter mass and spin-independent cross-section from future ton-scale direct detection experiments using germanium, xenon or argon as targets. Adopting realistic values for the exposure, energy threshold and resolution of Dark Matter experiments which will come online within 5 to 10 years, the degree of c

  75. Rubab Khan, K. Z. Stanek, C. S. Kochanek, A. Z. Bonanos

    We discuss the nature of the brightest mid-IR point source (which we dub Object X) in the nearby galaxy M33. Although multi-wavelength data on this object have existed in the literature for some time, it has not previously been recognized as the most luminous mid-IR object in M33 because it is entirely unremarkable in both optical and near-IR light. In the L

  76. Dimitris Stamatellos, Anaelle Maury, Anthony Whitworth, Philippe Andre

    A large fraction of brown dwarfs and low-mass H-burning stars may form by gravitational fragmentation of protostellar discs. We explore the conditions for disc fragmentation and we find that they are satisfied when a disc is large enough (>100 AU) so that its outer regions can cool efficiently, and it has enough mass to be gravitationally unstable, at such r

  77. Dmytro Volin

    This paper is devoted to integrable gl(n|m) spin chains which allow for formulation of the string hypothesis. Considering the thermodynamic limit of such spin chains, we derive linear functional equations that symmetricaly treat holes and particles. The functional equations naturally organize different types of excitations into a pattern equivalent to the on

  78. David Jerison, Lionel Levine, Scott Sheffield

    Let A(t) denote the cluster produced by internal diffusion limited aggregation (internal DLA) with t particles in dimension d > 2. We show that A(t) is approximately spherical, up to an O(\sqrt{\log t}) error.

  79. Clara Rojas, Máximo García-Sucre, Germán Urbina-Villalba

    In a previous report [10] it was shown that emulsion stability simulations are able to reproduce the lifetime of micrometer-size drops of hexadecane pressed by buoyancy against a planar water-hexadecane interface. It was confirmed that small drops (ri<10 μm) stabilized with β-casein behave as nondeformable particles, moving with a combination of Stokes and T

  80. Trond S. Ingebrigtsen, Søren Toxvaerd, Thomas B. Schrøder, Jeppe C. Dyre

    In the companion paper [Ingebrigtsen et al., arXiv:1012.3447] an algorithm was developed for tracing out a geodesic curve on the constant-potential-energy hypersurface. Here simulations of this NVU dynamics are compared to results for four other dynamics, both deterministic and stochastic. First, NVU dynamics is compared to the standard energy-conserving New

  81. David Landriault, Jean-François Renaud, Xiaowen Zhou

    In this paper, we compute the Laplace transform of occupation times (of the negative half-line) of spectrally negative Lévy processes. Our results are extensions of known results for standard Brownian motion and jump-diffusion processes. The results are expressed in terms of the so-called scale functions of the spectrally negative Lévy process and its Laplac

  82. Trond S. Ingebrigtsen, Søren Toxvaerd, Ole J. Heilmann, Thomas B. Schrøder

    An algorithm is derived for computer simulation of geodesics on the constant potential-energy hypersurface of a system of N classical particles. First, a basic time-reversible geodesic algorithm is derived by discretizing the geodesic stationarity condition and implementing the constant potential energy constraint via standard Lagrangian multipliers. The bas

  83. Ariel Zandivarez, Hector J. Martinez

    We perform an analysis of the luminosities of galaxies in groups in the SDSS DR7. We analyse the luminosity function (LF) as a function of group mass for different photometric bands, galaxy populations, galaxy positions within the groups, and the group surrounding large scale density. We find that M* brightens and alpha becomes steeper as a function of mass

  84. Gilles Pagès, Benedikt Wilbertz

    In this paper we establish the sharp rate of the optimal dual quantization problem. The notion of dual quantization was recently introduced in the paper [8], where it was shown that, at least in an Euclidean setting, dual quantizers are based on a Delaunay triangulation, the dual counterpart of the Voronoi tessellation on which &#34;regular&#34; quantization

  85. Wei Han, Roland K. Kawakami

    We investigate spin relaxation in graphene spin valves and observe strongly contrasting behavior for single layer graphene (SLG) and bilayer graphene (BLG). In SLG, the spin lifetime (τs) varies linearly with the momentum scattering time (τp) as carrier concentration is varied, indicating the dominance of Elliot-Yafet (EY) spin relaxation at low temperatures

  86. Tadahiro Oh, Jeremy Quastel

    We construct a Gibbs measure for the nonlinear Schrodinger equation (NLS) on the circle, conditioned on prescribed mass and momentum: d μ_{a,b} = Z^{-1} 1_{\int_T |u|^2 = a} 1_{i \int_T u \bar{u}_x = b} exp (\pm1/p \int_T |u|^p - 1/2 \int_{\T} |u|^2) d P for a \in R^+ and b \in R, where P is the complex-valued Wiener measure on the circle. We also show that

  87. Sascha Zöllner, G. M. Bruun, C. J. Pethick, S. M. Reimann

    We show that dipolar bosons and fermions confined in a quasi-one-dimensional ring trap exhibit a rich variety of states because their interaction is inhomogeneous. For purely repulsive interactions, with increasing strength of the dipolar coupling there is a crossover from a gas-like state to an inhomogeneous crystal-like one. For small enough angles between

  88. Tewodros Amdeberhan, Christoph Koutschan, Victor H. Moll, Eric S. Rowland

    For a polynomial P, we consider the sequence of iterated integrals of ln P(x). This sequence is expressed in terms of the zeros of P(x). In the special case of ln(1 + x^2), arithmetic properties of certain coefficients arising are described. Similar observations are made for ln(1 + x^3).

  89. Peter M. Gerdes

    While much work has been done to characterize the Turing degrees computing members of various collections of fast growing functions, much less has been done to characterize the rate of growth necessary to compute particular degrees. Prior work has shown that every degree computed by all sufficiently fast growing functions is uniformly computed by all suffici

  90. Semyon Litvinov

    The notion of uniform equicontinuity in measure at zero for sequences of additive maps from a normed space into the space of measurable operators associated with a semifinite von Neumann algebra is discussed. It is shown that uniform equicontinuity in measure at zero on a dense subset implies the uniform equicontinuity on the entire space, which is then appl

  91. J. D. Burton, E. Y. Tsymbal

    A giant tunneling electroresistance effect may be achieved in a ferroelectric tunnel junction by exploiting the magnetoelectric effect at the interface between a ferroelectric barrier and magnetic La1-xSrxMnO3 electrode. Using first-principles density functional theory we demonstrate that a few magnetic monolayers of La1-xSrxMnO3 near the interface act, in r

  92. Atsushi Higuchi, Donald Marolf, Ian A. Morrison

    We study the relation between two sets of correlators in interacting quantum field theory on de Sitter space. The first are correlators computed using in-in perturbation theory in the expanding cosmological patch of de Sitter space (also known as the conformal patch, or the Poincaré patch), and for which the free propagators are taken to be those of the free

  93. Franziska Schubert, Yuriy Mokrousov, Paolo Ferriani, Stefan Heinze

    Using first-principles calculations, we study the occurrence of non-collinear magnetic order in monatomic Mn chains. First, we focus on freestanding Mn chains and demonstrate that they exhibit a pronounced non-collinear ground state in a large range of interatomic distances between atoms in the chain. By artificially varying the atomic number of Mn we invest

  94. David Scheinker

    For each n,N>0 we construct a set of points x_1,...,x_M in D^n with the following property: if f is a rational inner function on D^n of degree strictly less than N and g is an analytic function mapping D^n to D that satisfies g(x_i)=f(x_i) for each i=1,...,M, then g=f on D^n. In terms of the Pick problem on D^n, our result implies that for any rational inner

  95. J. N. Yates, N. Achilleos, P. Guio

    The coupling of Jupiter&#39;s magnetosphere and ionosphere plays a vital role in creating its auroral emissions. The strength of these emissions is dependent on the difference in speed of the rotational flows within Jupiter&#39;s high-latitude thermosphere and the planet&#39;s magnetodisc. Using an azimuthally symmetric global circulation model, we have simu

  96. Paul Expert, Tim Evans, Vincent D. Blondel, Renaud Lambiotte

    Many complex systems are organized in the form of a network embedded in space. Important examples include the physical Internet infrastucture, road networks, flight connections, brain functional networks and social networks. The effect of space on network topology has recently come under the spotlight because of the emergence of pervasive technologies based

  97. Henriette Elvang, Daniel Z. Freedman, Michael Kiermaier

    Ward identities of SUSY and R-symmetry relate n-point amplitudes in supersymmetric theories. We review recent work in which these Ward identities are solved in N=4 SYM and N=8 supergravity. The solution, valid at both tree and loop level, expresses any (Next-to)^K MHV superamplitude in terms of a basis of ordinary amplitudes. Basis amplitudes are classified

  98. Stephan Durr, Giannis Koutsou

    We present a parameter-free Wilson-type lattice Dirac operator with an 81-point stencil for the covariant derivative and the Laplacian which attempts to minimize the breaking of rotational symmetry near the boundary of the Brillouin zone. The usefulness of this &#34;Brillouin operator&#34; in practical applications is explored by studying the scaling of pseu

  99. M. Balbo, R. Walter, C. Ferrigno, P. Bordas

    Aims. The Crab nebula displayed a large gamma-ray flare on September 18, 2010. To more closely understand the origin of this phenomenon, we analyze the INTEGRAL (20-500 keV) and FERMI (0.1-300 GeV) data collected almost simultaneously during the flare. Methods. We divide the available data into three different sets, corresponding to the pre-flare period, the

  100. Francesc Fité, Joan-C. Lario

    Let C be a smooth projective curve defined over a number field and let C&#39; be a twist of C. In this article we relate the l-adic representations attached to the l-adic Tate modules of the Jacobians of C and C&#39; through an Artin representation. This representation induces global relations between the local factors of the respective Hasse-Weil L-function