Research archive

arXiv papers from August 2009

The most recent 100 records published that month. Open any paper for its original abstract, citation metadata, related research, and reading tools.

  1. Luiz C. L. Botelho

    We give a proof for the existence of a weak solution on the initial-value problem of a non-linear damped propagation

  2. José Luis Romero

    We prove a result about producing new frames for general spline-type spaces by piecing together portions of known frames. Using spline-type spaces as models for the range of certain integral transforms, we obtain results for time-frequency decompositions and sampling.

  3. Serguei Saavedra, David Smith, Felix Reed-Tsochas

    This paper has been withdrawn by the authors.

  4. M. K. Chan, Q. O. Hu, J. Zhang, T. Kondo

    Measurements and modeling of electron spin transport and dynamics are used to characterize hyperfine interactions in Fe/GaAs devices with $n$-GaAs channels. Ga and As nuclei are polarized by electrically injected electron spins, and the nuclear polarization is detected indirectly through the depolarization of electron spins in the hyperfine field. The depend

  5. Erik Nielsen, Ralph W. Young, Richard P. Muller, M. S. Carroll

    Achieving low-error, exchange-interaction operations in quantum dots for quantum computing imposes simultaneous requirements on the exchange energy's dependence on applied voltages. A double quantum dot (DQD) qubit, approximated with a quadratic potential, is solved using a full configuration interaction method. This method is more accurate than Heitler-Lond

  6. D. B. Hume, C. W. Chou, T. Rosenband, D. J. Wineland

    We have investigated theoretically and experimentally a method for preparing Dicke states in trapped atomic ions. We consider a linear chain of $N$ ion qubits that is prepared in a particular Fock state of motion, $|m>$. The $m$ phonons are removed by applying a laser pulse globally to the $N$ qubits, and converting the motional excitation to $m$ flipped spi

  7. N. A. Bond, Z. Ivezic, B. Sesar, M. Juric

    We study Milky Way kinematics using a sample of 18.8 million main-sequence stars with r<20 and proper-motion measurements derived from SDSS and POSS astrometry, including ~170,000 stars with radial-velocity measurements from the SDSS spectroscopic survey. Distances to stars are determined using a photometric parallax relation, covering a distance range from

  8. Chia-Chun Chou, Angel S. Sanz, Salvador Miret-Artes, Robert E. Wyatt

    Quantum interference is investigated within the complex quantum Hamilton-Jacobi formalism. As shown in a previous work [Phys. Rev. Lett. 102, 250401 (2009)], complex quantum trajectories display helical wrapping around stagnation tubes and hyperbolic deflection near vortical tubes, these structures being prominent features of quantum caves in space-time Arga

  9. J. Ochab, P. F. Góra

    A modified Kuramoto model of synchronization in a finite discrete system of locally coupled oscillators is studied. The model consists of N oscillators with random natural frequencies arranged on a ring. It is shown analytically and numerically that finite-size systems may have many different synchronized stable solutions which are characterised by different

  10. Anne Bauer, Charles Baltay, Paolo Coppi, Ciro Donalek

    We identify 3,113 highly variable objects in 7,200 square degrees of the Palomar-QUEST Survey, which each varied by more than 0.4 magnitudes simultaneously in two broadband optical filters on timescales from hours to roughly 3.5 years. The primary goal of the selection is to find blazars by their well-known violent optical variability. Because most known bla

  11. Oldrich Spacil

    Methods of parabolic geometries have been recently used to construct a class of elliptic complexes on quaternionic manifolds, the Salamon's complex being the simplest case. The purpose of this paper is to describe an algorithm how to compute their analytical indices in terms of characteristic classes. Using this, we are able to derive some topological obstru

  12. Yee Kao, Tatsu Takeuchi

    We discuss possible constraints on R-parity violation from recently announced Belle/Babar results on the B\to\tau\nu branching fraction, and the bounds on \tau^-\to\ell^- K_S^0 (\ell=e or \mu) from Babar.

  13. Indranil Biswas, Jacques Hurtubise

    Let X_R be a geometrically irreducible smooth projective curve, defined over R, such that X_R does not have any real points. Let X= X_R\times_R C be the complex curve. We show that there is a universal real algebraic line bundle over X_R x Pic^d(X_R)$ if and only if $\chi(L)$ is odd for L in Pic^d(X_R)$. There is a universal quaternionic algebraic line bundl

  14. Iraklis S Konstantopoulos

    Star clusters represent the most common 'mode' of star formation. They are found in all types of environments, cascading down from galaxy groups and merging pairs through starbursts to normal galaxies and dwarves and even isolated regions in extragalactic space. As they maintain a link to the overall star formation in a system, they can be used as tracers of

  15. Emmanuel Amiot

    Several musical scales, like the major scale, can be described as finite arithmetic sequences modulo octave, i.e. chunks of an arithmetic sequence in a cyclic group. Hence the question of how many different arithmetic sequences in a cyclic group will give the same support set. We prove that this number is always a totient number and characterize the differen

  16. Nikolaos Kidonakis

    I present the latest results on the theoretical cross section for top-antitop pair production as well as for single top production at the Tevatron and the LHC. The calculations include higher-order soft-gluon corrections which are dominant near threshold. The top quark transverse momentum distribution is also presented.

  17. Dumitru Astefanesei, Maria J. Rodriguez, Stefan Theisen

    We use the conservation of the renormalized boundary stress-energy tensor to obtain the equilibrium condition for a general (thin or fat) black ring solution. We also investigate the role of the spatial stress in the thermodynamics of deformation within the quasilocal formalism of Brown and York and discuss the relation with other methods. In particular, we

  18. L. L. Cowie, A. J. Barger, E. M. Hu

    We construct a sample of low-redshift Ly-alpha emission-line selected sources from GALEX grism spectroscopy of nine deep fields to study the role of Ly-alpha emission in galaxy populations with cosmic time. Our final sample consists of 119 (141) sources selected in the redshift interval z=0.195-0.44 (z=0.65-1.25) from the FUV (NUV) channel. We classify the L

  19. Vivian U, Miguel A. Urbaneja, Rolf-Peter Kudritzki, Bradley A. Jacobs

    The quantitative spectral analysis of medium resolution optical spectra of A and B supergiants obtained with DEIMOS and ESI at the Keck Telescopes is used to determine a distance modulus of 24.93 +/- 0.11 mag for the Triangulum Galaxy M33. The analysis yields stellar effective temperatures, gravities, interstellar reddening, and extinction, the combination o

  20. Jonathan Thornburg

    I consider techniques for Berger-Oliger adaptive mesh refinement (AMR) when numerically solving partial differential equations with wave-like solutions, using characteristic (double-null) grids. Such AMR algorithms are naturally recursive, and the best-known past Berger-Oliger characteristic AMR algorithm, that of Pretorius & Lehner (J. Comp. Phys. 198 (2004

  21. Dragoş-Victor Anghel

    I introduce an ansatz for the exclusion statistics parameters of fractional exclusion statistics (FES) systems and I apply it to calculate the statistical distribution of particles from both, bosonic and fermionic perspectives. Then, to check the applicability of the ansatz, I calculate the FES parameters in three well-known models: in a Fermi liquid type of

  22. Joshua N. Cooper, Robert B. Ellis

    We analyze a deterministic form of the random walk on the integer line called the {\em liar machine}, similar to the rotor-router model, finding asymptotically tight pointwise and interval discrepancy bounds versus random walk. This provides an improvement in the best-known winning strategies in the binary symmetric pathological liar game with a linear fract

  23. Alexander Tchekhovskoy, Ramesh Narayan, Jonathan C. McKinney

    Achromatic breaks in afterglow light curves of gamma-ray bursts (GRBs) arise naturally if the product of the jet's Lorentz factor \gamma and opening angle \Theta_j satisfies (\gamma \Theta_j) >> 1 at the onset of the afterglow phase, i.e., soon after the conclusion of the prompt emission. Magnetohydrodynamic (MHD) simulations of collimated GRB jets generally

  24. L. A. Barbosa, J. K. L. da Silva

    To analyze the transport of information or material from a source to every node of a network we use two quantities introduced in the study of river networks: the cost and the flow. For a network with $K$ nodes and $M$ levels, we show that an upper bound to the global cost is $C_{0,max}\propto KM$. From numerical simulations for spanning tree networks with sc

  25. Trent J. Dupuy, Michael C. Liu

    We present detailed simulations of the Pan-STARRS-1 (PS1) multi-epoch, multi-band 3-pi Survey in order to assess its potential yield of transiting planets and eclipsing binaries. This survey differs from dedicated transit surveys in that it will cover the entire Northern sky but provide only sparsely sampled light curves. Since most eclipses would be detecte

  26. De-Chang Dai, Sourish Dutta, Dejan Stojkovic

    We examine a dark energy model where a scalar unparticle degree of freedom plays the role of quintessence. In particular, we study a model where the unparticle degree of freedom has a standard kinetic term and a simple mass potential, the evolution is slowly rolling and the field value is of the order of the unparticle energy scale ($\lambda_u$). We study ho

  27. Jay M. Pasachoff, William A. Jacobson, Alphonse C. Sterling

    We amassed statistics for quiet-sun chromosphere spicules at the limb using ground-based observations from the Swedish 1-m Solar Telescope on La Palma and simultaneously from NASA's Transition Region and Coronal Explorer (TRACE) spacecraft. The observations were obtained in July 2006. With the 0.2 arcsecond resolution obtained after maximizing the ground-bas

  28. A. Salvio

    We investigate the massive graviton contributions to 4D gravity in a 6D brane world scenario, whose bulk field content can include that of 6D chiral gauged supergravity. We consider a general class of solutions having 3-branes, 4D Poincare symmetry and axisymmetry in the internal space. We show that these contributions, which we compute analytically, can be

  29. Domenico Sapone, Martin Kunz

    Dark energy perturbations are normally either neglected or else included in a purely numerical way, obscuring their dependence on underlying parameters like the equation of state or the sound speed. However, while many different explanations for the dark energy can have the same equation of state, they usually differ in their perturbations so that these prov

  30. Dragoş-Victor Anghel

    In Phys. Rev. Lett. 67, 937 (1991) [1], Haldane introduced the fruitful concept of fractional exclusion statistics (FES). One of the most influential papers in which the thermodynamics of FES systems was deduced is Y.-S. Wu, Phys. Rev. Lett. 73, 922 (1994). Unfortunately, some important, but eventually subtle, properties of the exclusion statistics parameter

  31. John F. Donoghue

    In this talk, I describe and defend four non-standard claims about four effective field theories, and try to extract some lessons about the limits of effective field theory. The four theses (and a capsule diagnosis given in parentheses) are: 1) Kaon loops are not a reliable part of chiral perturbation theory (dimensional regularization does not know about th

  32. Max Tegmark, Matias Zaldarriaga

    We show that the class of antenna layouts for telescope arrays allowing cheap analysis hardware (with correlator cost scaling as N log N rather than N^2 with the number of antennas N) is encouragingly large, including not only previously discussed rectangular grids but also arbitrary hierarchies of such grids, with arbitrary rotations and shears at each leve

  33. Young-Jun Yu, Yue Zhao, Sunmin Ryu, Louis E. Brus

    We report variation of the work function for single and bi-layer graphene devices measured by scanning Kelvin probe microscopy (SKPM). Using the electric field effect, the work function of graphene can be adjusted as the gate voltage tunes the Fermi level across the charge neutrality point. Upon biasing the device, the surface potential map obtained by SKPM

  34. A. Cano, I. Paul

    The scattering of electrons with inhomogeneities produces modulations in the local density of states of a metal. We show that electron interference contributions to these modulations are affected by the magnetic field via the Aharonov-Bohm effect. This can be exploited in a simple STM setup that serves as an Aharonov-Bohm interferometer at the nanometer scal

  35. M. Vivek, R. Srianand, P. Noterdaeme, V. Mohan

    We report long-slit spectroscopic observations of SDSS J092712+294344 carried-out at the recently commissioned 2m telescope in IUCAA Girawali Observatory, India. This AGN-like source is known to feature three sets of emission lines at zem = 0.6972, 0.7020 and 0.7128. Different scenarios such as a recoiling black hole after asymmetric emission of gravitationa

  36. K. Benakli, M. D. Goodsell

    We present formulae for the calculation of Dirac gaugino masses at leading order in the supersymmetry breaking scale using the methods of analytic continuation in superspace and demonstrate a link with kinetic mixing, even for non-abelian gauginos. We illustrate the result through examples in field and string theory. We discuss the possibility that the singl

  37. G. Ghirlanda, G. Ghisellini, L. Nava

    We study the emission of the short/hard GRB 090510 at energies > 0.1 GeV as observed by the Large Area Telescope (LAT) onboard the Fermi satellite. The GeV flux rises in time as t^2 and decays as t^-1.5 up to 200 s. The peak of the high energy flux is delayed by 0.2 s with respect to the main ~MeV pulse detected by the Fermi Gamma Burst Monitor (GBM). Its en

  38. Jui-yu Chiu, Andreas Fuhrer, Randall Kelley, Aneesh V. Manohar

    Previous work on electroweak radiative corrections to high energy scattering using soft-collinear effective theory (SCET) has been extended to include external transverse and longitudinal gauge bosons and Higgs bosons. This allows one to compute radiative corrections to all parton-level hard scattering amplitudes in the standard model to NLL order, including

  39. Eiichi Hirose, Keita Kawabe, Daniel Sigg, Rana Adhikari

    We observed the effect of radiation pressure on the angular sensing and control system of the Laser Interferometer Gravitational-Wave Observatory (LIGO) interferometer's core optics at LIGO Hanford Observatory. This is the first measurement of this effect in a complete gravitational wave interferometer. Only one of the two angular modes survives with feedbac

  40. Franz Elsner, Benjamin D. Wandelt

    We describe an algorithm to generate temperature and polarization maps of the cosmic microwave background radiation containing non-Gaussianity of arbitrary local type. We apply an optimized quadrature scheme that allows us to predict and control integration accuracy, speed up the calculations, and reduce memory consumption by an order of magnitude. We genera

  41. Veronika E. Hubeny, Donald Marolf, Mukund Rangamani

    We recently argued that the dynamics of strongly coupled field theories in black hole backgrounds is related via the AdS/CFT correspondence to two new classes of AdS black hole solutions: black funnels, and black droplets suspended above a second disconnected horizon. The funnel solutions are dual to black holes coupling strongly to a field theory plasma. In

  42. R. D. Alexander, P. J. Armitage

    We present models of giant planet migration in evolving protoplanetary disks. Our disks evolve subject to viscous transport of angular momentum and photoevaporation, while planets undergo Type II migration. We use a Monte Carlo approach, running large numbers of models with a range in initial conditions. We find that relatively simple models can reproduce bo

  43. A. Reiners, J. L. Bean, K. F. Huber, S. Dreizler

    The detection of planets around very low-mass stars with the radial velocity method is hampered by the fact that these stars are very faint at optical wavelengths where the most high-precision spectrometers operate. We investigate the precision that can be achieved in radial velocity measurements of low mass stars in the near infrared (nIR) Y-, J-, and H-ban

  44. Silvia Bonoli, Francesco Shankar, Simon White, Volker Springel

    We use the large catalogues of haloes available for the Millennium Simulation to test whether recently merged haloes exhibit stronger large-scale clustering than other haloes of the same mass. This effect could help to understand the very strong clustering of quasars at high redshift. However, we find no statistically significant excess bias for recently mer

  45. Qifan Li

    In Baraka's paper [2], he obtained the Littlewood-Paley characterization of Campanato spaces $L^{2,\lambda}$ and introduced $\mathcal {L}^{p,\lambda,s}$ spaces. He showed that $\mathcal {L}^{2,\lambda,s}=(-\triangle)^{-\frac{s}{2}}L^{2,\lambda}$ for $0\leq\lambda<n+2$. In [7], by using the properties of fractional Carleson measures, J Xiao proved that for $n

  46. Bruno Bauwens

    We show that there are infinitely many binary strings z, such that the sum of the on-line decision complexity of predicting the even bits of z given the previous uneven bits, and the decision complexity of predicting the uneven bits given the previous event bits, exceeds the Kolmogorov complexity of z by a linear term in the length of z.

  47. Allan Adams, Joshua M. Lapan

    We compute the massless spectra of a set of flux vacua of the heterotic string. The vacua we study include well-known non-Kahler T^2-fibrations over K3 with SU(3) structure and intrinsic torsion. Following gauged linear sigma models of these vacua into phases governed by asymmetric Landau-Ginzburg orbifolds allows us to compute the spectrum using generalizat

  48. Jacob R. West, Bryan H. Fong, Daniel A. Lidar

    We present a near-optimal quantum dynamical decoupling scheme that eliminates general decoherence of a qubit to order n using O(n^2) pulses, an exponential decrease in pulses over all previous decoupling methods. Numerical simulations of a qubit coupled to a spin bath demonstrate the superior performance of the new pulse sequences.

  49. Jianhua Xing, Kenneth S Kim

    Reconstruction of equations of motion from incomplete or noisy data and dimension reduction are two fundamental problems in the study of dynamical systems with many degrees of freedom. For the latter extensive efforts have been made but with limited success to generalize the Zwanzig-Mori projection formalism, originally developed for Hamiltonian systems clos

  50. Charles D. Hill, Adrian P. Flitney, Nicolas C. Menicucci

    While it is known that shared quantum entanglement can offer improved solutions to a number of purely cooperative tasks for groups of remote agents, controversy remains regarding the legitimacy of quantum games in a competitive setting--in particular, whether they offer any advantage beyond what is achievable using classical resources. We construct a competi

  51. Woo Kyun Kim, Michael L. Falk

    Molecular dynamics simulations of frictional sliding in an Atomic Force Microscope (AFM) show a clear dependence of superlubricity between incommensurate surfaces on tip compliance and applied normal force. While the kinetic friction vanishes for rigid tips and low normal force, superlubric behavior breaks down for softer tips and high normal force. The simu

  52. A. Romanelli, Guzmán Hernández

    We study the resonances of the quantum kicked rotor subjected to an excitation that follows a deterministic time-dependent prescription. For the primary resonances we find an analytical relation between the long-time behavior of the standard deviation and the external kick strength. For the secondary resonances we obtain essentially the same result numerical

  53. T. Iwashita, T. Kumagai, R. Yamamoto

    We report an extension of the smoothed profile method (SPM)[Y. Nakayama, K. Kim, and R. Yamamoto, Eur. Phys. J. E {\bf 26}, 361(2008)], a direct numerical simulation method for calculating the complex modulus of the dispersion of particles, in which we introduce a temporally oscillatory external force into the system. The validity of the method was examined

  54. Diana Battefeld, Thorsten Battefeld

    We compute analytic expressions for the non-linearity parameters characterizing the bi- and tri-spectrum of primordial curvature perturbations generated during an inflationary epoch of the early universe driven by an arbitrary number of fields. We assume neither slow roll nor a separable potential; instead, to compute Non-Gaussianities, we assume a separable

  55. Walter Bergweiler, Alexandre Eremenko

    The equation in the title describes the number of bright images of a point source under lensing by an elliptic object with isothermal density. We prove that this equation has at most 6 solutions. Any number of solutions from 1 to 6 can actually occur.

  56. Hilding Neilson, Chow-Choong Ngeow, Shashi Kanbur, John B. Lester

    Recent observations of Cepheids using infrared interferometry and Spitzer photometry have detected the presence of circumstellar envelopes (CSE) of dust and it has been hypothesized that the CSE's are due to dust forming in a Cepheid wind. Here we use a modified Castor, Abbott & Klein formalism to produce a Cepheid wind, and this is used to estimate the cont

  57. Carpentier Michael

    Physics from beyond the Standard Model can induce four fermion operators involving a quark, an anti-quark, a lepton and an anti-lepton. The coefficients of these operators can be constrained by various observations. We update the bounds arising from tree level processes (rare lepton and meson decays, atomic parity violation, contact interaction and mu-e conv

  58. Lado Samushia

    High precision cosmological observations in last decade suggest that about 70% of our universe's energy density is in so called "Dark Energy" (DE). Observations show that DE has negative effective pressure and therefore unlike conventional energy sources accelerates the cosmic expansion instead of decelerating it. DE is highly uniform and has become a domina

  59. Mikolaj Korzynski

    A new definition of coarse-grained quantities describing the dust flow in General Relativity is proposed. It assigns the coarse--grained expansion, shear and vorticity to finite-size comoving domains of fluid in a covariant, coordinate-independent manner. The coarse--grained quantities are all quasi-local functionals, depending only on the geometry of the bo

  60. Miguel A. Sanchez-Conde

    Axion Like Particles (ALPs), postulated to solve the strong-CP problem, are predicted to couple with photons in the presence of magnetic fields, which may lead to a significant change in the observed spectra of gamma-ray sources such as AGNs. Here we simultaneously consider in the same framework both the photon/axion mixing that takes place in the gamma-ray

  61. Shusa Deng, Gerardo Ortiz, Lorenza Viola

    We investigate non-equilibrium dynamical scaling in adiabatic quench processes across quantum multicritical points. Our analysis shows that the resulting power-law scaling depends sensitively on the control path, and that anomalous critical exponents may emerge depending on the universality class. We argue that the observed anomalous behavior originates in t

  62. M. Iskin, J. K. Freericks

    We theoretically analyze Fermi-Bose mixtures consisting of light fermions and heavy bosons that are loaded into optical lattices (ignoring the trapping potential). To describe such mixtures, we consider the Fermi-Bose version of the Falicov-Kimball model on a periodic lattice. This model can be exactly mapped onto the spinless Fermi-Fermi Falicov-Kimball mod

  63. Eike Lau

    Let p be an odd prime. We show that the classification of p-divisible groups by Breuil windows and the classification of finite flat group schemes of p-power order by Breuil modules hold over any complete regular local ring with perfect residue field of characteristic p. We use a formalism of frames and windows with an abstract deformation theory that applie

  64. Eulalia Nualart

    In this paper, we consider a system of $k$ second order non-linear stochastic partial differential equations with spatial dimension $d \geq 1$, driven by a $q$-dimensional Gaussian noise, which is white in time and with some spatially homogeneous covariance. The case of a single equation and a one-dimensional noise, has largely been studied in the literature

  65. Alessandro Spadoni, Chiara Daraio

    Acoustic lenses are employed in a variety of applications, from biomedical imaging and surgery, to defense systems, but their performance is limited by their linear operational envelope and complexity. Here we show a dramatic focusing effect and the generation of large amplitude, compact acoustic pulses (sound bullets) in solid and fluid media, enabled by a

  66. V. Sessi, K. Kuhnke, A. Enders, J. Zhang

    The growth dynamics of submonolayer coverages of Cobalt during buffer layer assisted growth on Ag(111) and Pt(111) substrates is investigated by variable temperature scanning tunneling microscopy in the temperature range between 80 and 150 Kelvin. It is found that attractive cluster-substrate interactions can govern the cluster formation on the Xe buffer lay

  67. Lasse Leskelä, Falk Unger

    This paper studies a spatial queueing system on a circle, polled at random locations by a myopic server that can only observe customers in a bounded neighborhood. The server operates according to a greedy policy, always serving the nearest customer in its neighborhood, and leaving the system unchanged at polling instants where the neighborhood is empty. This

  68. James Jenkins, Terry Goldman

    Low energy photon production is an important background to many current and future precision neutrino experiments. We present a phenomenological study of t-channel radiative corrections to neutral current neutrino nucleus scattering. After introducing the relevant processes and phenomenological coupling constants, we will explore the derived energy and angul

  69. KLOE Collaboration

    We present a precise measurement of the ratio R_K = \Gamma(Ke2(\gamma))/\Gamma(K\mu2(\gamma)) performed with the KLOE detector. The results are based on data collected at the Frascati e^+e^- collider DAFNE for an integrated luminosity of 2.2 fb^{-1}. We find R_K = (2.493\pm0.025_{stat}\pm0.019_{syst})\times 10^{-5}, in agreement with the Standard Model expec

  70. Aristeu R. P. Lima, Axel Pelster

    Recently, a seminal STIRAP experiment allowed the creation of 40K-87Rb molecules in the rovibrational ground state [K.-K. Ni et al., Science 322, 231 (2008)]. In order to describe such a polarized dipolar Fermi gas in the hydrodynamic regime, we work out a variational time-dependent Hartree-Fock approach. With this we calculate dynamical properties of such a

  71. Bagmeet Behera, Stefan J. Wagner

    The Extragalactic Background Light (EBL) causes attenuation of the VHE spectra of extragalactic sources, via pair-production. The amount of attenuation depends on the distance of the source, i.e. on the integration over the line of sight path taken by the VHE photons. The line of sight path calculation, depends on the values of the cosmological parameters an

  72. G. Granger, A. Kam, S. A. Studenikin, A. S. Sachrajda

    The purpose of this work is to fabricate ribbon-like InGaAs and InAsP wires embedded in InP ridge structures and investigate their transport properties. The InP ridge structures that contain the wires are selectively grown by chemical beam epitaxy (CBE) on pre-patterned InP substrates. To optimize the growth and micro-fabrication processes for electronic tra

  73. Jasmina Hasanhodzic, Andrew W. Lo, Emanuele Viola

    We propose to study market efficiency from a computational viewpoint. Borrowing from theoretical computer science, we define a market to be \emph{efficient with respect to resources $S$} (e.g., time, memory) if no strategy using resources $S$ can make a profit. As a first step, we consider memory-$m$ strategies whose action at time $t$ depends only on the $m

  74. Bagmeet Behera, Marcus Hauser, Stefan J. Wagner

    To explore the correlation in the GeV band (i.e. the inverse-Compton component) with the optical band (i.e. the synchrotron component) of blazars that are bright in high energies, the light curves of a number of blazars monitored with the Fermi Gamma-ray Space Telescope (FGST), were compared to the corresponding light curves recorded with the Automatic Teles

  75. M. Davier, A. Hoecker, B. Malaescu, C. Z. Yuan

    Using recently published, high-precision pi+pi- cross section data by the BABAR experiment from the analysis of e+e- events with high-energy photon radiation in the initial state, we reevaluate the lowest order hadronic contribution a_mu[had,LO] to the anomalous magnetic moment of the muon. We employ newly developed software featuring improved data interpola

  76. N. Auerbach, S. Shlomo

    Experiments at the Relativistic Heavy Ion Collider (RHIC) suggest that the state of matter produced in the experiments has a low shear-viscosity to entropy-density ratio. We ask here the question what is this ratio in usual finite nuclei at low temperature. We use the experimental and theoretical results for the widths of giant vibrational states in nuclei i

  77. Bogdan Szal

    In the present paper we consider the trigonometric series with (b,r)-general monotone and (b,r)-rest bounded variation coefficients. Necessary and sufficien conditions of L-convergence for such series are obtained in terms of the coefficients.

  78. Ines Safi

    A general non-linear response theory is derived for an arbitrary time-dependent Hamiltonian, not necessarily obeying time-reversal symmetry. This allows us to obtain a greatly generalized Kubo type formula. Applied to a mesoscopic system with any type of interactions, and coupled to multiple probes and gates with arbitrarily time-dependent voltages, we deriv

  79. M. C. Larciprete, F. A. Bovino, A. Belardini, C. Sibilia

    We analyze the relationship between the bound and the free waves in the noncollinear SHG scheme, along with the vectorial conservation law for the different components arising when there are two pump beams impinging on the sample with two different incidence angles. The generated power is systematically investigated, by varying the polarization state of both

  80. Sivan Leviyang

    During an infection, HIV experiences strong selection by immune system T cells. Recent experimental work has shown that MHC escape mutations form an important pathway for HIV to avoid such selection. In this paper, we study a model of MHC escape mutation. The model is a predator-prey model with two prey, composed of two HIV variants, and one predator, the im

  81. Paulo R. F. Pinto, M. S. Baptista, Isabel S. Labouriau

    It is known that unstable periodic orbits of a given map give information about the natural measure of a chaotic attractor. In this work we show how these orbits can be used to calculate the density function of the first Poincar\'e returns. The close relation between periodic orbits and the Poincar\'e returns allows for estimates of relevant quantities in dy

  82. Bagmeet Behera, Stefan J. Wagner

    A new strategy to select candidate blazars for VHE observations, that gives an inherently complete sample from an all-sky compilation (excluding a narrow region around the galactic plane) of GeV-bright blazars is presented. The strategy is based on selecting candidate VHE blazars from a GeV-detected blazar sample, namely the LAT-bright-AGN-sample (LBAS) of t

  83. D. Okuyama, M. Nakamura, Y. Wakabayashi, H. Itoh

    Effect of growth orientation on charge- and orbital-ordering (CO-OO) phenomena has been studied for Pr0.5Ca0.5MnO3 epitaxial thin films fabricated on (LaAlO3)0.3-(SrAl0.5Ta0.5O3)0.7 (LSAT) substrates by means of resistivity, synchrotron x-ray diffraction, and polarized optical microscopy measurements. CO-OO transition is observed around 220 K for a film grow

  84. Demetres Christofides, Daniela Kühn, Deryk Osthus

    In this paper we give an approximate answer to a question of Nash-Williams from 1970: we show that for every \alpha > 0, every sufficiently large graph on n vertices with minimum degree at least (1/2 + \alpha)n contains at least n/8 edge-disjoint Hamilton cycles. More generally, we give an asymptotically best possible answer for the number of edge-disjoint H

  85. I. Ramirez, C. Allende Prieto, D. L. Lambert, L. Koesterke

    We have obtained ultra-high quality spectra (R=180,000; S/N>300) with unprecedented wavelength coverage (4400 to 7400 A) for a number of stars covering most of the HR diagram in order to test the predictions of models of stellar surface convection. Line bisectors and core wavelength shifts are both measured and modeled, allowing us to validate and/or reveal

  86. Jose F. Alves, Vilton Pinheiro

    We consider a partially hyperbolic set $K$ on a Riemannian manifold $M$ whose tangent space splits as $T_K M=E^{cu}\oplus E^{s}$, for which the centre-unstable direction $E^{cu}$ expands non-uniformly on some local unstable disk. We show that under these assumptions $f$ induces a Gibbs-Markov structure. Moreover, the decay of the return time function can be

  87. P. Massignan, A. Sanpera, M. Lewenstein

    We propose to realize a p-wave superfluid using bosons mixed with a single species of fermions in a deep optical lattice. We analyze with a self-consistent method its excitation spectrum in presence of a vortex, and we point out the range of interaction strengths in which the zero-energy mode with topological character exists on a finite optical lattice. Lat

  88. Rodanthy Tzani, Alexios P. Polychronakos

    The recent "correlation breakdown" in the modeling of credit default swaps, in which model correlations had to exceed 100% in order to reproduce market prices of supersenior tranches, is analyzed and argued to be a fundamental market inconsistency rather than an inadequacy of the specific model. As a consequence, markets under such conditions are exposed to

  89. Radomir Slavchov, Roumen Tsekov

    Electron gases in metals are described as quantum charged Newtonian viscous fluids experiencing Ohmic Darcy friction on the solid lattice ions as well. The dispersion relation of the electron acoustic waves is derived, which shows the existence of new quantum diffusion processes. The electric double layer near a metal surface is studied, which exhibits a qua

  90. Roland Knevel

    The super upper half plane, this is the ordinary upper half plane with additional odd (anticommuting) directions, admits a transitive super action of a certain super Lie group G . First we define the spaces of super automorphic and cusp forms on the super upper half plane for an ordinary lattice in G and give an asymptotic formula for their dimensions for hi

  91. David Sherman

    We demonstrate how virtually all common cardinal invariants associated to a von Neumann algebra M can be computed from the decomposability number, dec(M), and the minimal cardinality of a generating set, gen(M). Applications include the equivalence of the well-known generator problem, "Is every separably-acting von Neumann algebra singly-generated?", with th

  92. M Diaz-Aguilo, E Garcia-Berro, A Lobo

    The magnetic diagnostics subsystem of the LISA Technology Package (LTP) on board the LISA PathFinder (LPF) spacecraft includes a set of four tri-axial fluxgate magnetometers, intended to measure with high precision the magnetic field at their respective positions. However, their readouts do not provide a direct measurement of the magnetic field at the positi

  93. Nigel P. Byott, G. Griffith Elder

    This paper justifies an assertion in (Elder, Proc AMS 137 (2009), no 4, 1193--1203) that Galois scaffolds make the questions of Galois module structure tractable. Let $k$ be a perfect field of characteristic $p$ and let $K=k((T))$. For the class of characteristic $p$ elementary abelian $p$-extensions $L/K$ with Galois scaffolds described in mentioned paper,

  94. Chetana Jain, Biswajit Paul, Anjan Dutta

    We present the orbital X-ray modulation study of three high mass X- ray binary systems, IGR J18027-2016, IGR J18483-0311 and IGR J16318-4848 using data obtained with RXTE-ASM, Swift-BAT and INTEGRAL-ISGRI. Using the long term light curves of the eclipsing HMXB IGR J18027-2016, obtained with Swift-BAT in the energy range 15-50 keV and INTEGRAL-ISGRI in the en

  95. C. Payette, S. Amaha, T. Hatano, K. Ono

    We study level mixing in the single particle energy spectrum of one of the constituent quantum dots in a vertical double quantum dot by performing magneto-resonant-tunneling spectroscopy. The device used in this study differs from previous vertical double quantum dot devices in that the single side gate is now split into four separate gates. Because of the p

  96. Ş. G. Söyler, A. B. Kuklov, L. Pollet, N. V. Prokof'ev

    In the experiment on superfluid transport in solid He4 [PRL {\bf 100}, 235301 (2008)], Ray and Hallock observed an {\it anomalously large isochoric compressibility}: the supersolid samples demonstrated a significant and apparently spatially uniform response of density and pressure to chemical potential, applied locally through Vycor "electrodes". We propose

  97. Uffe Haagerup, Troels Steenstrup, Ryszard Szwarc

    Let X be a homogeneous tree of degree q+1 (for q between 2 and infinity) and let f be a complex function on X times X for which f(x,y) only depend on the distance between x and y in X. Our main result gives a necessary and sufficient condition for such a function to be a Schur multiplier on X times X. Moreover, we find a closed expression for the Schur norm

  98. Matyas Barczy, Marton Ispany, Gyula Pap

    In this paper the asymptotic behavior of an unstable integer-valued autoregressive model of order p (INAR(p)) is described. Under a natural assumption it is proved that the sequence of appropriately scaled random step functions formed from an unstable INAR(p) process converges weakly towards a squared Bessel process. We note that this limit behavior is quite

  99. J. -U. Ness

    For several novae, a bright X-ray source with a spectrum resembling the class of Super Soft X-ray Sources (SSS) has been observed a few weeks to months after outburst. Novae are powered by explosive nuclear burning on the surface of a white dwarf, and enough energy is produced to power a radiatively driven wind. Owing to the evolution of the opacity of the e

  100. John F. Donoghue, Daniel Wyler

    We discuss the kinematics of the particles that make up a Reggeon in field theory, using the terminology of the Soft Collinear Effective Theory (SCET). Reggeization sums a series of strongly-ordered collinear emissions resulting in an overall Reggeon exchange that falls in the Glauber or Coulomb kinematic region. This is an extremely multi-scale problem and