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June 2009 arXiv papers — page 25

Showing 2,4012,500 of 5,471 papers

  1. Ivan Gatica Araus

    In this paper we develop a theory called $σ$-Set Theory, in which we present an axiom system developed from the study of Set Theories of Zermelo-Fraenkel, Neumann-Bernays-Godel and Morse-Kelley. In $σ$-Set Theory, we present the proper existence of objects called $σ$-antielement, $σ$-antiset, natural numbers, antinatural numbers and generated $σ$-set by two

  2. Johan Bijnens, Ilaria Jemos

    We report on a search of relations valid at order $p^6$ in Chiral Perturbation Theory. We have found relations between $ππ$, $πK$ scattering, $K_{\ell4}$ decays, masses and decay constants and scalar and vector form factors. In this paper we give the relations and a first numerical check of them.

  3. E. Paladino, A. Mastellone, A. D'Arrigo, G. Falci

    We present a general route to reduce inhomogeneous broadening in nanodevices due to 1/f noise. We apply this method to a universal two-qubit gate and demonstrate that for selected optimal couplings, a high-efficient gate can be implemented even in the presence of 1/f noise. Entanglement degradation due to interplay of 1/f and quantum noise is quantified via

  4. Michael Gabler, Ulrich Sperhake, Nils Andersson

    The effects of nonlinear oscillations in compact stars are attracting considerable current interest. In order to study such phenomena in the framework of fully nonlinear general relativity, highly accurate numerical studies are required. We present a numerical scheme specifically tailored for studies, based on formulating the time evolution in terms of devia

  5. Pirin Erdogdu, Ofer Lahav

    We predict the acceleration of the Local Group generated by the 2MASS Redshift Survey within the framework of LambdaCDM and the halo model of galaxies. We show that as the galaxy fluctuations derived from the halo model have more power on small scales compared with the mass fluctuations, the misalignment angle between the CMB velocity vector and the 2MRS dip

  6. Amalendu Krishna

    For a smooth quasi-projective scheme $X$ over a field $k$ with an action of a reductive group, we establish a spectral sequence connecting the equivariant and the ordinary higher Chow groups of $X$. For $X$ smooth and projective, we show that this spectral sequence degenerates, leading to an explicit relation between the equivariant and the ordinary higher C

  7. Selman Akbulut

    Starting with the Dolgachev surface E(1)_{2,3} we construct an infinite family of distinct exotic copies of the rational surface E(1), each of which admits a handlebody decomposition without 1- and 3- handles, and we draw these handlebodies.

  8. Nathalie Ysard, Laurent Verstraete

    The emission of cold dust grains at long wavelengths will soon be observed by the Planck and Herschel satellites and provide new constraints on the nature of interstellar dust. The microwave anomalous emission, proposed to be due to spinning PAHs, should help to better define these species. Moreover, understanding the fluctuations of the anomalous emission o

  9. Fabien Buisseret, Vincent Mathieu, Claude Semay

    The relativistic flux tube model is an effective description of confined quarks and gluons in which the confining interaction is carried by the flux tube, a Nambu-Goto string. We first show that the relativistic flux tube model can be applied to glueballs seen as bound states of transverse constituent gluons. After a comparison of that approach with usual sp

  10. Patrick O. Perry, Patrick J. Wolfe

    Rank estimation is a classical model order selection problem that arises in a variety of important statistical signal and array processing systems, yet is addressed relatively infrequently in the extant literature. Here we present sample covariance asymptotics stemming from random matrix theory, and bring them to bear on the problem of optimal rank estimatio

  11. J. A. Bergstra, C. A. Middelburg

    This paper concerns instruction sequences that contain probabilistic instructions, i.e. instructions that are themselves probabilistic by nature. We propose several kinds of probabilistic instructions, provide an informal operational meaning for each of them, and discuss related work. On purpose, we refrain from providing an ad hoc formal meaning for the pro

  12. S. Sridhar, Kandaswamy Subramanian

    We study large-scale dynamo action due to turbulence in the presence of a linear shear flow. Our treatment is quasilinear and equivalent to the standard `first order smoothing approximation'. However it is non perturbative in the shear strength. We first derive an integro-differential equation for the evolution of the mean magnetic field, by systematic use o

  13. Alok C. Gupta, Paul J. Wiita, Jeewan C. Pandey, A. K. Srivastava

    We withdraw our claim that a component in an XMM-Newton satellite light curve of the BL Lacertae object S5 0716 + 714 shows quasi-periodic oscillations (QPOs) of $\sim$30 minutes. Although both our original periodogram and wavelet analyses gave consistent results, the data do not lead to a statistically significant result once red-noise at low frequencies is

  14. Yaozhong Hu, David Nualart, Jian Song

    We establish a version of the Feynman-Kac formula for the multidimensional stochastic heat equation with a multiplicative fractional Brownian sheet. We use the techniques of Malliavin calculus to prove that the process defined by the Feynman-Kac formula is a weak solution of the stochastic heat equation. From the Feynman-Kac formula, we establish the smoothn

  15. Terence Tao

    Let $d \geq 3$. We consider the global Cauchy problem for the generalised Navier-Stokes system \partial_t u + (u \cdot \nabla) u &= - D^2 u - \nabla p \nabla \cdot u &= 0 u(0,x) &= u_0(x) for $u: \R^+ \times \R^d \to \R^d$ and $p: \R^+ \times \R^d \to \R$, where $u_0: \R^d \to \R^d$ is smooth and divergence free, and $D$ is a Fourier multiplier whose symbol

  16. Claude Cibils, Maria Julia Redondo, Andrea Solotar

    The main purpose of this paper is to provide explicit computations of the fundamental group of several algebras. For this purpose, given a $k$-algebra $A$, we consider the category of all connected gradings of $A$ by a group $G$ and we study the relation between gradings and Galois coverings. This theoretical tool gives information about the fundamental grou

  17. Seokcheon Lee

    We investigate the exact analytic solutions for the growths of the dark matter and the baryon in sub-horizon scale. The growth of the dark matter $δ_{\DM}$ is related to that of the halos. Thus, the exact solution for the growth of the dark matter is important to obtain the proper properties of dark matter halos. However, the dark energy model dependence of

  18. Tianshu Luo, Yimu Guo

    In this paper an approach is proposed to represent a class of dissipative mechanical systems by corresponding infinite-dimensional Hamiltonian systems. This approach is based upon the following structure: for any non-conservative classical mechanical system and arbitrary initial conditions, there exists a conservative system; both systems share one and only

  19. Markku P. V. Stenberg, Rogerio de Sousa

    We propose a model for the pair of electromagnon excitations observed in the class of multiferroic materials {\it R}MnO$_3$ ({\it R} is a rare-earth ion). The model is based on a harmonic cycloid ground state interacting with a zone-edge magnon and its twin excitation separated in momentum space by two times the cycloid wave vector. The pair of electromagnon

  20. S. J. Seltzer, M. V. Romalis

    Antirelaxation surface coatings allow long spin relaxation times in alkali-metal cells without buffer gas, enabling faster diffusion of the alkali atoms throughout the cell and giving larger signals due to narrower optical linewidths. Effective coatings were previously unavailable for operation at temperatures above 80 C. We demonstrate that octadecyltrichlo

  21. P. M. Chesler, A. Gynther, A. Vuorinen

    We study thermal corrections to the dispersion relations of massive fundamental particles immersed in weakly coupled non-Abelian plasmas. The cases covered include quarks in the QCD (quark-gluon) plasma, as well as N=2 quarks and scalars in an N=4 Super Yang-Mills plasma. We perform the calculations to leading order in a weak coupling expansion, and consider

  22. Marcelo Botta Cantcheff

    We study the entanglement of closed strings degrees of freedom in order to investigate the microscopic structure and statistics of objects as D-branes. By considering the macroscopic pure state (MPS) limit, whenever the entanglement entropy goes to zero (in such a way that the macroscopic properties of the state are preserved), we show that boundary states m

  23. Andriy Myronenko, Xubo Song

    We introduce an adaptive regularization approach. In contrast to conventional Tikhonov regularization, which specifies a fixed regularization operator, we estimate it simultaneously with parameters. From a Bayesian perspective we estimate the prior distribution on parameters assuming that it is close to some given model distribution. We constrain the prior d

  24. Nicholas Scott, Michele Cappellari, Roger L. Davies, R. Bacon

    We present the results of an investigation of the local escape velocity (Vesc) - line strength index relationship for 48 early type galaxies from the SAURON sample, the first such study based on a large sample of galaxies with both detailed integral field observations and extensive dynamical modelling. Values of Vesc are computed using Multi Gaussian Expansi

  25. C A Holmes, G J Milburn

    We describe an opto-mechanical system in which the coupling between optical and mechanical degrees of freedom takes the form of a fully quantised third-order parametric interaction. Two physical realisations are proposed: a harmonically trapped atom in a standing wave and the `membrane in the middle' model. The dominant resonant interaction corresponds t

  26. R. Navarro, R. Carretero-Gonzalez, P. G. Kevrekidis

    We study the interactions between two atomic species in a binary Bose-Einstein condensate to revisit the conditions for miscibility, oscillatory dynamics between the species, steady state solutions and their stability. By employing a variational approach for a quasi one-dimensional, two-atomic species, condensate we obtain equations of motion for the paramet

  27. L. L. Samojeden, G. M. Kremer, F. P. Devecchi

    In this work we analyze the effects produced by bosonic and fermionic constituents, including quantum corrections, in two-dimensional (2D) cosmological models. We focus on a gravitational theory related to the Callan-Giddings-Harvey-Strominger model, to simulate the dynamics of a young, spatially-lineal, universe. The cosmic substratum is formed by an {\it i

  28. Olivier Lardiere, Rodolphe Conan, Colin Bradley, Kate Jackson

    Sodium Laser Guide Stars (LGSs) are elongated sources due to the thickness and the finite distance of the sodium layer. The fluctuations of the sodium layer altitude and atom density profile induce errors on centroid measurements of elongated spots, and generate spurious optical aberrations in closed--loop adaptive optics (AO) systems. According to an analyt

  29. Salvador Barraza-Lopez, Peter M. Albrecht, Joseph W. Lyding

    We present a study on the mechanical configuration and the electronic properties of semiconducting carbon nanotubes supported by partially depassivated silicon substrates, as inferred from topographic and spectroscopic data acquired with a room-temperature ultrahigh vacuum scanning tunneling microscope and density-functional theory calculations. A mechanical

  30. Toru Okuda, Galina V. Lipunova, Diego Molteni

    We examine the jets and the disc of SS 433 at super-Eddington luminosities with 600 times Eddington critical accretion rate by time-dependent two-dimensional radiation hydrodynamical calculations, assuming alpha-model for the viscosity. One-dimensional supercritical accretion disc models with mass loss or advection are used as the initial configurations of t

  31. B. Sibthorpe, P. Chanial, M. Griffin

    Instrument simulators are becoming ever more useful for planning and analysing large astronomy survey data. In this paper we present a simulator for the Herschel-SPIRE photometer. We describe the models it uses and the form of the input and output data. The SPIRE photometer simulator is a software package which uses theoretical models, along with flight mode

  32. Matthew J. Patitz, Scott M. Summers

    We review some recent results related to the self-assembly of infinite structures in the Tile Assembly Model. These results include impossibility results, as well as novel tile assembly systems in which shapes and patterns that represent various notions of computation self-assemble. Several open questions are also presented and motivated.

  33. B. Shklyar

    The exact controllability to the origin for linear evolution control equation is considered.The problem is investigated by its transformation to infinite linear moment problem. Conditions for the existence of solution for infinite linear moment problem has been obtained. The obtained results are applied to the zero controllability for control evolution equat

  34. Rafael López

    In this paper we review some author's results about Weingarten surfaces in Euclidean space $\r^3$ and hyperbolic space $\h^3$. We stress here in the search of examples of linear Weingarten surfaces that satisfy a certain geometric property. First, we consider Weingarten surfaces in $\r^3$ that are foliated by circles, proving that the surface is rotation

  35. Zheng Gan, Helge Krueger

    We construct examples, that log Hölder continuity of the integrated density of states cannot be improved. Our examples are limit-periodic.

  36. Rafael López

    It is known that planar disks and small spherical caps are the only constant mean curvature graphs whose boundary is a round circle. Usually, the proof invokes the Maximum Principle for elliptic equations. This paper presents a new proof of this result motivated by an article due to Reilly. Our proof utilizes a flux formula for surfaces with constant mean cu

  37. Jeffrey A. Rich, Ann Merchant Boesgaard

    The abundance of beryllium in the oldest, most metal-poor stars acts as a probe of early star formation and Galactic chemical evolution. We have analyzed high-resolution, high signal-to-noise Keck/HIRES spectra of 24 stars with [Fe/H] from -2.3 to -3.5 in order to determine the history of Be abundances and explore the possibility of a Be plateau. We have det

  38. Andrey V. Kravtsov

    A decade ago cosmological simulations of increasingly higher resolution were used to demonstrate that virialized regions of Cold Dark Matter (CDM) halos are filled with a multitude of dense, gravitationally-bound clumps. These dark matter subhalos are central regions of halos that survived strong gravitational tidal forces and dynamical friction during the h

  39. Robert Roloff, Walter Pötz

    A process tomography based optimization scheme for open quantum systems is used to determine the performance limits of Josephson charge qubits within current experimental means. The qubit is modeled microscopically as an open quantum system taking into account state leakage, as well as environment-induced dephasing based on experimental noise spectra. Within

  40. Hsiao-Wen Chen, John S. Mulchaey

    (Abridged) We present an imaging and spectroscopic survey of galaxies in fields around QSOs HE0226-4110, PKS0405-123, and PG1216+069. The fields are selected to have ultraviolet echelle spectra available, which uncover 195 Lya absorbers and 13 OVI absorbers along the three sightlines. We obtain robust redshifts for 1104 galaxies of rest-frame absolute magnit

  41. Heidi Jo Newberg, Brian Yanny, Benjamin A. Willett

    We show that there is a low metallicity tidal stream that runs along l=143 deg. in the South Galactic Cap, about 34 kpc from the Sun, discovered from SEGUE stellar velocities. Since the most concentrated detections are in the Cetus constellation, and the orbital path is nearly polar, we name it the Cetus Polar Stream (CPS). Although it is spatially coinciden

  42. Rafael F. Lang, Wolfgang Seidel

    The search for direct interactions of dark matter particles remains one of the most pressing challenges of contemporary experimental physics. A variety of different approaches is required to probe the available parameter space and to meet the technological challenges. Here, we review the experimental efforts towards the detection of direct dark matter intera

  43. Steven P. Allanson, Michael J. Hudson, Russell J. Smith, John R. Lucey

    This paper addresses the challenge of understanding the typical star formation histories of red sequence galaxies, using linestrength indices and mass-to-light ratios as complementary constraints on their stellar age distribution. We construct simple parametric models of the star formation history that bracket a range of scenarios, and fit these models to th

  44. Fred Lunnon

    We review the concept of the number wall as an alternative to the traditional linear complexity profile (LCP), and sketch the relationship to other topics such as linear feedback shift-register (LFSR) and context-free Lindenmayer (D0L) sequences. A remarkable ternary analogue of the Thue-Morse sequence is introduced having deficiency 2 modulo 3, and this pro

  45. Eric Goles, Pierre-Etienne Meunier, Ivan Rapaport, Guillaume Theyssier

    The goal of this paper is to show why the framework of communication complexity seems suitable for the study of cellular automata. Researchers have tackled different algorithmic problems ranging from the complexity of predicting to the decidability of different dynamical properties of cellular automata. But the difference here is that we look for communicati

  46. Ai-Hua Fan, Lingmin Liao, Ji-Hua Ma

    We consider sets of real numbers in $[0,1)$ with prescribed frequencies of partial quotients in their regular continued fraction expansions. It is shown that the Hausdorff dimensions of these sets, always bounded from below by $1/2$, are given by a modified variational principle.

  47. A. Gomez-Marin, J. M. Sancho

    Here we study a pumping device capable of maintaining a density gradient and a flux of particles across a membrane. Its driving mechanism is based on the flashing ratchet effect powered by the random telegraph process in the presence of thermal fluctuations. Unlike Brownian motors, the concentrations at both reservoir boundaries need to be implemented as bou

  48. David Radnell, Eric Schippers

    We show that the infinite-dimensional Teichmueller space of a Riemann surface whose boundary consists of n closed curves is a holomorphic fiber space over the Teichmueller space of n-punctured surfaces. Each fiber is a complex Banach manifold modeled on a two-dimensional extension of the universal Teichmueller space. The local model of the fiber, together wi

  49. M. Daniel, W. J. de Wit, D. Dravins, D. Kieda

    The imminent availability of large arrays of large light collectors deployed to exploit atmospheric Cherenkov radiation for gamma-ray astronomy at more than 100GeV, motivates the growing interest in application of intensity interferometry in astronomy. Indeed, planned arrays numbering up to one hundred telescopes will offer close to 5,000 baselines, ranging

  50. D. S. L. Figueira, D. Mustafa, L. R. Tessler, N. C. Frateschi

    We present a resonant approach to enhance 1550nm emission efficiency of amorphous silicon sub-oxide doped with Er3+ (a-SiOx<Er>) layers with silicon nanoclusters (Si-NC). Two distinct techniques were combined to provide a structure that allowed increasing approximately 12x the 1550nm emission. First, layers of SiO2 were obtained by conventional wet oxidation

  51. M. V. Fedorov, Yu. M. Mikhailova, P. A. Volkov

    A double-Gaussian model and the Schmidt modes are found for the biphoton wave function characterizing spontaneous parametric down-conversion with the degenerate collinear phase-matching of the type I and with a pulsed pump. The obtained results are valid for all durations of the pump pulses, short, long and intermediately long.

  52. L. Fernández-Jambrina

    In this lecture a new formalism for constructing electromagnetic surface sources for static axisymmetric electrovacs is presented. The electrostatic and magnetostatic sources are derived from the discontinuities of the scalar potentials. This formalism allows the inclusion of two kinds of dipole sources: Sheets of dipoles and the dipole moment of a distribut

  53. Michael C. R. Johnson

    Let $(X,\mathcal{B},μ)$ be a probability space and let $T_1,..., T_l$ be $l$ commuting invertible measure preserving transformations \linebreak of $X$. We show that if $T_1^{c_1} ... T_l^{c_l}$ is ergodic for each $(c_1,...,c_l)\neq (0,...,0)$, then the averages $\frac{1}{|Φ_N|}\sum_{u\inΦ_N}\prod_{i=1}^r T_1^{p_{i1}(u)}... T_l^{p_{il}(u)}f_i$ converge in $L

  54. Tian-Jun Li, Yongbin Ruan

    This is a survey on symplectic birational geometry. In arbitrary dimension, this subject is centered around the notion of uniruledness. In low dimensions, we will also discuss Kodaira dimension and minimality.

  55. L. Fernández-Jambrina

    In this talk it is shown a way for constructing magnetic surface sources for stationary axisymmetric electrovac spacetimes possessing a non-smooth electromagnetic Ernst potential. The magnetic moment density is related to this lack of smoothness and its calculation involves solving a linear elliptic differential equation. As an application the results are us

  56. Byung-Yoon Park, Vicente Vento

    We review an approach, developed over the past few years, to describe hadronic matter at finite density and temperature, whose underlying theoretical framework is the Skyrme model, an effective low energy theory rooted in large $N_c$ QCD. In this approach matter is described by various crystal structures of skyrmions, classical topological solitons carrying

  57. Roberto Fontana, Giovanni Pistone

    The joint use of counting functions, Hilbert basis and Markov basis allows to define a procedure to generate all the fractions that satisfy a given set of constraints in terms of orthogonality. The general case of mixed level designs, without restrictions on the number of levels of each factor (like primes or power of primes) is studied. This new methodology

  58. Vassilios G. Papageorgiou, Anastasios G. Tongas

    We present Yang-Baxter maps associated to elliptic curves. They are related to discrete versions of the Krichever-Novikov and the Landau-Lifshits equations. A lifting of scalar integrable quad-graph equations to two-field equations is also shown.

  59. Grégory Lafitte

    We show some incompleteness results a la Chaitin using the busy beaver functions. Then, with the help of ordinal logics, we show how to obtain a theory in which the values of the busy beaver functions can be provably established and use this to reveal a structure on the provability of the values of these functions.

  60. Olivier Bournez, Jérémie Chalopin, Johanne Cohen, Xavier Koegler

    Population protocols have been introduced as a model of sensor networks consisting of very limited mobile agents with no control over their own movement: A collection of anonymous agents, modeled by finite automata, interact in pairs according to some rules. Predicates on the initial configurations that can be computed by such protocols have been characteriz

  61. Nick Ramsey

    We construct a rigid-analytic map from the the author&#39;s half-integral weight cuspidal eigencurve to its integral weight counterpart that interpolates the classical Shimura lifting.

  62. Miljenko Cemeljic, Jose Gracia, Nektarios Vlahakis, Kanaris Tsinganos

    Axisymmetric resistive MHD simulations for radially self-similar initial conditions are performed, using the NIRVANA code. The magnetic diffusivity could occur in outflows above an accretion disk, being transferred from the underlying disk into the disk corona by MHD turbulence (anomalous turbulent diffusivity), or as a result of ambipolar diffusion in parti

  63. Andre Nathan, Valmir C. Barbosa

    When a neuron fires and the resulting action potential travels down its axon toward other neurons' dendrites, the effect on each of those neurons is mediated by the weight of the synapse that separates it from the firing neuron. This weight, in turn, is affected by the postsynaptic neuron's response through a mechanism that is thought to underlie important p

  64. David Doty, Matthew J. Patitz, Scott M. Summers

    We prove that if a subset X of the integer Cartesian plane weakly self-assembles at temperature 1 in a deterministic (Winfree) tile assembly system satisfying a natural condition known as *pumpability*, then X is a finite union of doubly periodic sets. This shows that only the most simple of infinite shapes and patterns can be constructed using pumpable temp

  65. Nick Ramsey

    In this paper we define Banach spaces of overconvergent half-integral weight $p$-adic modular forms and Banach modules of families of overconvergent half-integral weight $p$-adic modular forms over admissible open subsets of weight space. Both spaces are equipped with a continuous Hecke action for which $U_{p^2}$ is moreover compact. The modules of families

  66. Matthew Cook

    Rule 110 is a cellular automaton that performs repeated simultaneous updates of an infinite row of binary values. The values are updated in the following way: 0s are changed to 1s at all positions where the value to the right is a 1, while 1s are changed to 0s at all positions where the values to the left and right are both 1. Though trivial to define, the b

  67. Leonid Berezansky, Elena Braverman, Sandra Pinelas

    For a mixed (advanced--delay) differential equation with variable delays and coefficients $$ \dot{x}(t) \pm a(t)x(g(t)) \mp b(t)x(h(t)) = 0, t\geq t_0 $$ where $$ a(t)\geq 0, b(t)\geq 0, g(t)\leq t, h(t)\geq t $$ explicit nonoscillation conditions are obtained.

  68. Cristina Cachero, Jesús Pardillo

    Requirements engineering is known to be a key factor for the success of software projects. Inside this discipline, goal-oriented requirements engineering approaches have shown specially suitable to deal with projects where it is necessary to capture the alignment between system requirements and stakeholders&#39; needs, as is the case of data-warehousing proj

  69. M. R. Calvo, M. J. Caturla, D. Jacob, C. Untiedt

    The dynamic deformation upon stretching of Ni nanowires as those formed with mechanically controllable break junctions or with a scanning tunneling microscope is studied both experimentally and theoretically. Molecular dynamics simulations of the breaking process are performed. In addition, and in order to compare with experiments, we also compute the transp

  70. Gaetano Zimbardo

    We propose a new model for explaining the observations of more than mass proportional heating of heavy ions in the polar solar corona. We point out that a large number of small scale intermittent shock waves can be present in the solar corona. The energization mechanism is, essentially, the ion reflection off supercritical quasi-perpendicular collisionless s

  71. Yuri Bozhkov

    We establish a generalization to Riemannian manifolds of the Caffarelli-Kohn-Nirenberg inequality. The applied method is based on the use of conformal Killing vector fields and Enzo Mitidieri&#39;s approach to Hardy inequalities.

  72. Efi Fogel

    We present two exact implementations of efficient output-sensitive algorithms that compute Minkowski sums of two convex polyhedra in 3D. We do not assume general position. Namely, we handle degenerate input, and produce exact results. We provide a tight bound on the exact maximum complexity of Minkowski sums of polytopes in 3D in terms of the number of facet

  73. Leonid Berezansky, Elena Braverman

    The Bohl-Perron result on exponential dichotomy for a linear difference equation $$ x(n+1)-x(n) + \sum_{l=1}^m a_l(n)x(h_l(n))=0, h_l(n)\leq n, $$ states (under some natural conditions) that if all solutions of the non-homogeneous equation with a bounded right hand side are bounded, then the relevant homogeneous equation is exponentially stable. According to

  74. Nick Ramsey

    We introduce a geometric formalism for studying modular forms of half-integral weight and explore some of its basic properties. Geometric Hecke operators are constructed and some basic spaces of $p$-adic forms are introduced. The $p$-adic theory is greatly expanded in subsequent papers, making that part of this paper largely obsolete.

  75. Cristian S. Calude

    Universality is one of the most important ideas in computability theory. There are various criteria of simplicity for universal Turing machines. Probably the most popular one is to count the number of states/symbols. This criterion is more complex than it may appear at a first glance. In this note we review recent results in Algorithmic Information Theory an

  76. Thomas Jagemann

    The absolute magnitude of the brightest galaxy of clusters varies remarkably little and is nearly independent of all other physical properties of the cluster as, e.g., its spatial extension or its richness. The question arises whether the observed small scatter is compatible with the assumption of dynamical evolution of the cluster. This is investigated with

  77. Sergey Verlan, Yurii Rogozhin

    Symport/antiport P systems provide a very simple machinery inspired by corresponding operations in the living cell. It turns out that systems of small descriptional complexity are needed to achieve the universality by these systems. This makes them a good candidate for small universal devices replacing register machines for different simulations, especially

  78. Felix Ali Mehmeti, Robert Haller-Dintelmann, Virginie Régnier

    We consider the Klein-Gordon equation on a star-shaped network composed of n half-axes connected at their origins. We add a potential which is constant but different on each branch. The corresponding spatial operator is self-adjoint and we state explicit expressions for its resolvent and its resolution of the identity in terms of generalized eigenfunctions.

  79. V. P. Konchakovski, M. Hauer, M. I. Gorenstein, E. L. Bratkovskaya

    Particle number fluctuations and correlations in nucleus-nucleus collisions at SPS and RHIC energies are studied within the statistical hadron-resonance gas model in different statistical ensembles and in the Hadron-String-Dynamics (HSD) transport approach. Event-by-event fluctuations of the proton to pion and kaon to proton number ratios are calculated in t

  80. Klaus Sutner

    We introduce a formal definition of Wolfram&#39;s notion of computational process based on cellular automata, a physics-like model of computation. There is a natural classification of these processes into decidable, intermediate and complete. It is shown that in the context of standard finite injury priority arguments one cannot establish the existence of an

  81. Nicolas Ollinger, Gaétan Richard

    Signals are a classical tool used in cellular automata constructions that proved to be useful for language recognition or firing-squad synchronisation. Particles and collisions formalize this idea one step further, describing regular nets of colliding signals. In the present paper, we investigate the use of particles and collisions for constructions involvin

  82. H. Witala, R. Skibinski, J. Golak, W. Glockle

    We extend our approach to incorporate the proton-proton (pp) Coulomb force into the three-nucleon (3N) Faddeev calculations from elastic proton-deuteron (pd) scattering to the breakup process. The main new ingredient is a 3-dimensional screened pp Coulomb t-matrix obtained by a numerical solution of the 3-dimensional Lippmann-Schwinger equation. We demonstra

  83. Jérôme Durand-Lose

    This article aims at providing signal machines as small as possible able to perform any computation (in the classical understanding). After presenting signal machines, it is shown how to get universal ones from Turing machines, cellular-automata and cyclic tag systems. Finally a halting universal signal machine with 13 meta-signals and 21 collision rules is

  84. Sergey Andreyev

    All the modern day applications have the interface, absolutely defined by the developers. The use of adaptive interface or dynamic layout allows some variations, but even all of them are predetermined on the design stage, because the best reaction (from designer&#39;s view) on any possible users&#39; movement was hardcoded. But there is a different world of

  85. F. R. Ford, J. A. Gracey

    We compute the two loop MSbar correction to the Gribov mass gap equation in the Landau gauge using the Gribov-Zwanziger Lagrangian with massive quarks included. The computation involves dilogarithms of complex arguments and reproduces the known gap equation when the quark mass tends to zero.

  86. E. Bellingeri, R. Buzio, A. Gerbi, D. Marre&#39;

    Superconducting epitaxial FeSe0.5Te0.5 thin films were prepared on SrTiO3 (001) substrates by pulsed laser deposition. The high purity of the phase, the quality of the growth and the epitaxy were studied with different experimental techniques: X-rays diffraction, reflection high energy electron diffraction, scanning tunnelling microscopy and atomic force mic

  87. Narad Rampersad, Jeffrey Shallit

    We consider variations on the following problem: given an NFA M and a pattern p, does there exist an x in L(M) such that p matches x? We consider the restricted problem where M only accepts a finite language. We also consider the variation where the pattern p is required only to match a factor of x. We show that both of these problems are NP-complete. We als

  88. S. L. Skornyakov, A. V. Efremov, N. A. Skorikov, M. A. Korotin

    Electronic correlations in the Fe-pnictide BaFe2As2 are explored within LDA+DMFT, the combination of density functional theory with dynamical mean-field theory. While the correlated band structure is substantially renormalized there is only little transfer of spectral weight. The computed k-integrated and k-resolved spectral functions are in good agreement w

  89. Marloes H. Maathuis

    We study computational aspects of the nonparametric maximum likelihood estimator (NPMLE) for the distribution function of bivariate interval censored data. The computation of the NPMLE consists of two steps: a parameter reduction step and an optimization step. In this paper we focus on the reduction step. We introduce two new reduction algorithms: the Tree a

  90. A. G. Ramm

    The governing equation is $[\nabla^2+k^2-q(x)]u=0$ in $\R^3$. It is shown that any desired potential $q(x)$, vanishing outside a bounded domain $D$, can be obtained if one embeds into D many small scatterers $q_m(x)$, vanishing outside balls $B_m:=\{x: |x-x_m|<a\}$, such that $q_m=A_m$ in $B_m$, $q_m=0$ outside $B_m$, $1\leq m \leq M$, $M=M(a)$. It is proved

  91. Nicolas Ollinger

    This talk advocates intrinsic universality as a notion to identify simple cellular automata with complex computational behavior. After an historical introduction and proper definitions of intrinsic universality, which is discussed with respect to Turing and circuit universality, we discuss construction methods for small intrinsically universal cellular autom

  92. Belen Garcia, Hector Giacomini, Jesus Perez del Rio

    We consider in this work planar polynomial differential systems having a polynomial first integral. We prove that these systems can be obtained from a linear system through a polynomial change of variables.

  93. B. P. Xie, L. F. Zhu, K. Yang, B. Zhou

    The state-resolved differential cross sections for both the 1s2 1S0 - 1s2s 1S0 monopolar transition and the 1s2 1S0 - 1s2p 1P1 dipolar transition of atomic helium have been measured over a large momentum transfer region by the high-resolution inelastic X-ray scattering (IXS) for the first time. The almost perfect match of the present measurement with the the

  94. Alexander Okhotin

    A restricted case of the Circuit Value Problem known as the Sequential NOR Circuit Value Problem was recently used to obtain very succinct examples of conjunctive grammars, Boolean grammars and language equations representing P-complete languages (Okhotin, http://dx.doi.org/10.1007/978-3-540-74593-8_23 &#34;A simple P-complete problem and its representations

  95. Laura A. Golick, Karen E. Daniels

    The size-segregation of granular materials, a process colloquially known as the Brazil Nut Effect, has generally been thought to proceed faster the greater the size difference of the particles. We experimentally investigate sheared bidisperse granular materials as a function of the size ratio of the two species, and find that the mixing rate at low confining

  96. P. Kazemi, M. Eckart

    In the first part of this contribution we prove the global existence and uniqueness of a trajectory that globally converges to the minimizer of the Gross-Pitaevskii energy functional for a large class of external potentials. Using the method of Sobolev gradients we can provide an explicit construction of this minimizing sequence. In the second part we numeri

  97. Viktor V. Begun, Mark I. Gorenstein, Walter Greiner

    We study a smooth crossover transition in the gas of quark-gluon bags. The equation of state at high temperature is that of the quark-gluon plasma. However, the system consists of the bags with finite volumes which are defined by the model parameters of the mass-volume bag spectrum. Possible structures in this {\it cluster} quark-gluon plasma are classified.

  98. L. Palova, P. Chandra, K. M. Rabe

    Using first principles calculations, we present a magnetostructural effect in the BiFeO3-BiMnO3 nanocheckerboard that is not found in either bulk parent compound or in BiFeO3-BiMnO3 superlattices. We also demonstrate that the atomic-scale checkerboard has a multiferroic ground state with the desired properties of each constitutent material: polar and ferrima

  99. Mari Kobayashi, Yingbin Liang, Shlomo Shamai, Merouane Debbah

    We study the compound multi-input multi-output (MIMO) broadcast channel with confidential messages (BCC), where one transmitter sends a common message to two receivers and two confidential messages respectively to each receiver. The channel state may take one of a finite set of states, and the transmitter knows the state set but does not know the realization

  100. Manfred Kudlek

    The paper puts into discussion the concept of universality, in particular for structures not of the power of Turing computability. The question arises if for such structures a universal structure of the same kind exists or not. For that the construction of universal Turing machines and those with some constraints are presented in some detail.