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January 2009 arXiv papers — page 21

Showing 2,0012,100 of 4,902 papers

  1. K. C. Steenbrugge, M. Fenovcik, J. S. Kaastra, E. Costantini

    Methods. We analyse two observations taken with the Low Energy Transmission Grating Spectrometer of Chandra. We investigated the spectral response to a sudden flux decrease by a factor of 5, which occurred during the second observation. Results. We detect a highly ionised absorption component with an outflow velocity of -4670 km/s, one of the highest outflow

  2. A. Silantyev

    The thesis was defended by the author in University of Angers (France). It consists of four parts. The fist part (in French) is introductory and is devoted to relation between quantum groups, integrable systems and statistical models. In the second part (in English) the transition function of the periodic Toda chain is interpreted in terms of the formalism o

  3. J. Vorberger, D. O. Gericke

    We investigate the effects of collective modes on the temperature relaxation rates in fully coupled electron-ion systems. Firstly, the well-understood limit of weakly coupled plasmas is considered and the coupled mode formula within the random phase approximation is derived starting from the Lenard-Balescu kinetic equation. We show how the frequency integrat

  4. Monica Vazquez Acosta

    The cross section measurements of the Higgs boson production in the vector boson fusion (VBF) process at the LHC followed by a Higgs boson decay into tautau, WW and gamma gamma will significantly extend the possibility of Higgs boson coupling measurements. Prospective analyses with the CMS experiment are discussed for the H-> gammagamma, WW and tautau decay

  5. Barry F. Madore, Wendy L. Freedman, J. Catanzarite, Mauricio Navarrete

    We report VRI CCD observations of nine Cepheids in the South Polar (Sculptor) Group spiral galaxy NGC 0247. Periods of these Cepheids range from 20 to 70 days. Over the past 20 years the very brightest Cepheid in our sample, NGC 0247:[MF09] C1, has decreased its period by 6%, faded by 0.8 mag in the V band, and become bluer by 0.23 mag in (V-I). A multi-wave

  6. G. Gaeta

    We consider generalized (possibly depending on fields as well as on space-time variables) gauge transformations and gauge symmetries in the context of general -- that is, possibly non variational nor covariant -- differential equations. In this case the relevant principal bundle admits the first jet bundle (of the phase manifold) as an associated bundle, at

  7. Gavin Ramsay, Simon Rosen, Pasi Hakala, Thomas Barclay

    We report the discovery of an eclipsing polar, 2XMMi J225036.9+573154, using XMM-Newton. It was discovered by searching the light curves in the 2XMMi catalogue for objects showing X-ray variability. Its X-ray light curve shows a total eclipse of the white dwarf by the secondary star every 174 mins. An extended pre-eclipse absorption dip is observed in soft X

  8. Silvia Penati, Alberto Romagnoni, Massimo Siani

    We consider nonanticommutative SYM theories with chiral matter in the adjoint representation of the SU(N) x U(1) gauge group. In a superspace setup and manifest background covariant approach we investigate the one-loop renormalization of the theory when a cubic superpotential is present. The structure of the divergent terms reveals that the theory simply obt

  9. Jia-An Yan, W. Y. Ruan, M. Y. Chou

    The phonon dispersions of monolayer and few-layer graphene (AB bilayer, ABA and ABC trilayers) are investigated using the density-functional perturbation theory (DFPT). Compared with the monolayer, the optical phonon $E_{2g}$ mode at $Γ$ splits into two and three doubly degenerate branches for bilayer and trilayer graphene, respectively, due to the weak inte

  10. T. Roscilde, M. Rodriguez, K. Eckert, O. Romero-Isart

    We show how spin-spin correlations, detected in a non-destructive way via spatially resolved quantum polarization spectroscopy, strongly characterize various phases realized in trapped ultracold fermionic atoms. Polarization degrees of freedom of the light couple to spatially resolved components of the atomic spin. In this way quantum fluctuations of matter

  11. Serge Bouc

    Let $k$ be a field of characteristic $p>0$. Call a finite group $G$ a poco group over $k$ if any finitely generated cohomological Mackey functor for $G$ over $k$ has polynomial growth. The main result of this paper is that $G$ is a poco group over $k$ if and only if the Sylow $p$-subgroups of $G$ are cyclic, when $p>2$, or have sectional rank at most 2, when

  12. Francois Gallet, Delphine Arcizet, Pierre Bohec, Alain Richert

    Living cells exhibit an important out-of-equilibrium mechanical activity, mainly due to the forces generated by molecular motors. These motor proteins, acting individually or collectively on the cytoskeleton, contribute to the violation of the fluctuation-dissipation theorem in living systems. In this work we probe the cytoskeletal out-of-equilibrium dynamic

  13. Jia-An Yan, W. Y. Ruan, M. Y. Chou

    We present a first-principles study of the electron-phonon (e-ph) interactions and their contributions to the linewidths for the optical phonon modes at $Γ$ and K in one to three-layer graphene. It is found that due to the interlayer coupling and the stacking geometry, the high-frequency optical phonon modes in few-layer graphene couple with different valenc

  14. Fressin Francois, Guillot Tristan, Nesta Lionel

    Each transiting planet discovered is characterized by 7 measurable quantities, that may or may not be linked together (planet mass, radius, orbital period, and star mass, radius, effective temperature, and metallicity). Correlations between planet mass and period, surface gravity and period, planet radius and star temperature have been previously observed am

  15. Nicolas Fournier

    We consider the problem of the simulation of Levy-driven stochastic differential equations. It is generally impossible to simulate the increments of a Levy-process. Thus in addition to an Euler scheme, we have to simulate approximately these increments. We use a method in which the large jumps are simulated exactly, while the small jumps are approximated by

  16. Ernest G. Kalnins, Jonathan M. Kress, Willard Miller, Sarah Post

    The structure theory for the quadratic algebra generated by first and second order constants of the motion for 2D second order superintegrable systems with nondegenerate (3-parameter) and or 2-parameter potentials is well understood, but the results for the strictly 1-parameter case have been incomplete. Here we work out this structure theory and prove that

  17. Peter J. Bickel, Elizaveta Levina

    This paper considers regularizing a covariance matrix of $p$ variables estimated from $n$ observations, by hard thresholding. We show that the thresholded estimate is consistent in the operator norm as long as the true covariance matrix is sparse in a suitable sense, the variables are Gaussian or sub-Gaussian, and $(\log p)/n\to0$, and obtain explicit rates.

  18. M. Anselmino, M. Boglione, U. D'Alesio, S. Melis

    The Sivers distributions recently extracted from semi-inclusive deep inelastic scattering data [1] are used to compute estimates for Sivers asymmetries in Drell-Yan processes which are being planned at several facilities (RHIC, COMPASS, J-PARC, PAX, PANDA, NICA (JINR) and SPASCHARM (IHEP)). Most of these asymmetries turn out to be large and could allow a cle

  19. B. Mehlig, M. Wilkinson, V. Bezuglyy, K. Gustavsson

    We consider the diffusion of independent particles experiencing random accelerations by a space- and time-dependent force as well as viscous damping. This model can exhibit several asymptotic behaviours, depending upon the limiting cases which are considered, some of which have been discussed in earlier work. Here we explore the full space of dimensionless p

  20. J. Horak, M. A. Abramowicz, W. Kluzniak, P. Rebusco

    We explore some properties of twin kilohertz quasiperiodic oscillations (QPOs) in a simple toy-model consisting of two oscillation modes coupled by a general nonlinear force. We examine resonant effects by slowly varying the values of the tunable, and nearly commensurable, eigenfrequencies. The behavior of the actual oscillation frequencies and amplitudes du

  21. Yu. Loiko, C. Serrat, R. Vilaseca, V. Ahufinger

    We demonstrate that a Doppler broadened two-level medium can be made transparent to a laser pulse by an appropriate adiabatic variation of the laser field amplitude and its nominal detuning. This new technique of adiabatic self-induced transparency (ASIT) is compared with the well known self-induced transparency (SIT) phenomenon, showing that the adiabatic m

  22. Terry G. McRae, Warwick P. Bowen

    The output fields of a pair of coherently coupled nonlinear optical cavities are found to exhibit strong optical entanglement. For sufficiently strong coupling the quantum correlations become asynchronous providing a resource for quantum information protocols such as all-optical quantum memories. A straightforward experimental implementation applicable to wh

  23. Daniel Barlet, H. -M. Maire

    Existence of oblique polar lines for the meromorphic extension of the current valued function $\int |f|^{2λ}|g|^{2μ}\square$ is given under the following hypotheses: $f$ and $g$ are holomorphic function germs in $\CC^{n+1}$ such that $g$ is non-singular, the germ $S:=\ens{\d f\wedge \d g =0}$ is one dimensional, and $g|_S$ is proper and finite. The main tool

  24. Paul Glendinning, Piotr Kowalczyk

    We demonstrate on a representative example of a planar hybrid system with digital sampling a sudden transition from a stable limit cycle to the onset of chaotic dynamics. We show that the scaling law in the size of the attractor is proportional to the digital sampling time $τ$ for sufficiently small values of $τ.$ Numerical and analytical results are given.

  25. Carlo Stanghellini, Daniele Dallacasa, Monica Orienti

    We present a sample of sources with convex radio spectra peaking at frequencies above a few GHz, known as "High Frequency Peakers" (HFPs). A "bright" sample with a flux density limit of 300 mJy at 5 GHz has been presented by Dallacasa et al. (2000). Here we present the "faint" sample with flux density between 50 and 300 mJy at 5GHz, r

  26. Tae-Suk Kim, J. Ieda, S. Maekawa

    We report on a quantum description of the domain wall (DW) motion under a spin current. A bound magnon, which is the zero mode of DW, is found to play a dominant role in DW dynamics. The bound magnon acquires its inertia by the hard axis anisotropy and is a free particle even under the spin current. The full transfer of spin angular momentum from the spin cu

  27. Carlo Stanghellini, Daniele Dallacasa, Tiziana Venturi, An Tao

    The measurement of proper motions in CSOs is a powerful tool to determine the dynamical evolution of the newly born extragalactic radio sources. We observed 3 CSOs with the VLBA in 2004 and in 2006 to monitor changes in their structure and measure the separation velocity of the hot spots. It is important to increase the size of the samples of CSOs with measu

  28. Laurent Charles, Julien Marche

    We consider the representation space of a compact surface, that is the space of morphisms from the fundamental group to SU(2) up to conjugation. We show that the trace functions associated to multicurves on the surface are linearly independent as functions on the representation space. The proof relies on the Fourier decomposition of the trace functions with

  29. Stefan Groot Nibbelink, Johannes Held, Fabian Ruehle, Michele Trapletti

    Heterotic orbifolds provide promising constructions of MSSM-like models in string theory. We investigate the connection of such orbifold models with smooth Calabi-Yau compactifications by examining resolutions of the T^6/Z6-II orbifold (which are far from unique) with Abelian gauge fluxes. These gauge backgrounds are topologically characterized by weight vec

  30. S. Scopetta

    The measurement of nuclear Generalized Parton Distributions (GPDs) will represent a valuable tool to understand the structure of bound nucleons in the nuclear medium, as well as the role of non-nucleonic degrees of freedom in the phenomenology of hard scattering off nuclei. By using a realistic microscopic approach for the evaluation of GPDs of 3He, it will

  31. V. Janis

    We discuss restrictions on the existence of the diffusion pole in the translationally invariant diagrammatic treatment of disordered electron systems. We use the Bethe-Salpeter equations for the two-particle vertex in the electron-hole and the electron-electron scattering channels and derive for systems with time reversal symmetry a nonlinear integral equati

  32. Ioannis Florakis, Costas Kounnas

    We investigate the existence of string vacua with Massive Spectrum Degeneracy Symmetry (MSDS) in Heterotic and Type II orbifold constructions. We present a classification of all possible Z_2^N-orbifolds with MSDS symmetry that can be constructed in the formalism of the 2d free fermionic construction. We explicitly construct several two-dimensional models who

  33. Carlos Lourenco, Ramona Vogt, Hermine K. Woehri

    Charmonium states are expected to be considerably suppressed in the case of quark-gluon plasma formation in high-energy heavy-ion collisions. However, a robust identification of suppression patterns as signatures of a deconfined QCD medium requires a detailed understanding of the "normal nuclear absorption" already present in proton-nucleus collision

  34. A. Gaudilliere

    These notes constitute the introduction to potential theory I exposed at the XIIth brazilian school of probability inside Elisabetta Scoppola's Introduction to Metastability.

  35. Holger Brenner

    We give a survey about some recent work on tight closure and Hilbert-Kunz theory from the viewpoint of vector bundles

  36. C. P. de Vries E. Costantini

    High quality, high resolution X-ray spectra were obtained of Sco X-1 with the Reflection Grating Spectrometer (RGS) on board the XMM-Newton satellite. The spectrum around the Oxygen K-edge is searched for signatures indicative for EXAFS. Analysis shows a clear indication for the existence of EXAFS with photo-electron scattering distances in the absorbing med

  37. Abderrazak Bouaziz

    We study the possibility of factoring a covariant distribution on reductive Lie algebras as finite sum of products of an invariant distribution by a covariant polynomial.

  38. Bert Van Schaeybroeck

    Motivated by the recent experiments on Bose-Einstein mixtures with tunable interactions we study repulsive weakly interacting Bose mixtures at finite temperature. We obtain phase diagrams using Hartree-Fock theory which are directly applicable to experimentally trapped systems. Almost all features of the diagrams can be characterized using simple physical in

  39. P. J. Koppinen, I. J. Maasilta

    We have investigated electronic cooling of suspended nanowires with SINIS tunnel junction coolers. The suspended samples consist of a free standing nanowire suspended by four narrow ($\sim$ 200 nm) bridges. We have compared two different cooler designs for cooling the suspended nanowire. We demonstrate that cooling of the nanowire is possible with a proper S

  40. Jamie Parsons, Simon F. Ross

    We study the spectrum of the worldsheet theory of the bosonic closed string in the massless and extremal rotating BTZ black holes. We use a hyperbolic Wakimoto representation of the SL(2,R) currents to construct vertex operators for the string modes on these backgrounds. We argue that there are tachyons in the twisted sector, but these are not localised near

  41. J. Jasche, F. S. Kitaura, T. A. Ensslin

    We address the problem of discretizing continuous cosmological signals such as a galaxy distribution for further processing with Fast Fourier techniques. Discretizing, in particular representing continuous signals by discrete sets of sample points, introduces an enormous loss of information, which has to be understood in detail if one wants to make inference

  42. J. R. Forshaw

    After a brief resume of the theory underpinning the central exclusive process (CEP) pp \to p+H+p, attention is focussed upon Higgs bosons produced in the Standard Model, the MSSM and the NMSSM. In all cases, CEP adds significantly to the physics potential of the LHC and in some scenarios it may be crucial.

  43. J. R. Forshaw, M. H. Seymour

    After a brief introduction to the physics of soft gluons in QCD we present a surprising prediction. Dijet production in hadron-hadron collisions provides the paradigm, i.e. h_1 +h_2 \to jj+X. In particular, we look at the case where there is a restriction placed on the emission of any further jets in the region in between the primary (highest p_T) dijets. Lo

  44. A. Kortyka, R. Puzniak, A. Wisniewski, H. W. Weber

    We report on measurements on Y1-xPrxBa2Cu3O7-delta single crystals, with x varying from 0 to 2.4%. The upper and the lower critical fields, Hc2 and Hc1, the Ginzburg-Landau parameter and the critical current density, Jc(B), were determined from magnetization measurements and the effective media approach scaling method. We present the influence of Pr substitu

  45. I. S. Glass, M. Schultheis, J. A. D. L. Blommaert, R. Sahai

    Asymptotic Giant Branch variables are found to obey period-luminosity relations in the mid-IR similar to those seen at K_S (2.14 microns), even at 24 microns where emission from circumstellar dust is expected to be dominant. Their loci in the M, logP diagrams are essentially the same for the LMC and for NGC6522 in spite of different ages and metallicities. T

  46. F. Fohr, A. A. Serga, T. Schneider, J. Hamrle

    A recently reported phase sensitive Brillouin light scattering technique is improved by use of a magnetic modulator. This modulator is based on Brillouin light scattering in a thin ferrite film. Using this magnetic modulator in time- and space Brillouin light scattering measurements we have increased phase contrast and excluded influence of optical inhomogen

  47. Viet-Anh Nguyen, Peter Pflug

    We establish extension theorems for separately holomorphic mappings defined on sets of the form W\setminus M with values in a complex analytic space which possesses the Hartogs extension property. Here W is a 2-fold cross of arbitrary complex manifolds and M is a set of singularities which is locally pluripolar (resp. thin) in fibers.

  48. Claudius Gros

    The human brain is autonomously active. To understand the functional role of this self-sustained neural activity, and its interplay with the sensory data input stream, is an important question in cognitive system research and we review here the present state of theoretical modelling. This review will start with a brief overview of the experimental efforts, t

  49. J. Robrade, J. H. M. M. Schmitt

    Methods: We analyse an XMM-Newton observation of 1RXS J115928.5-524717, an ultracool dwarf with spectral type M9 and compare its X-ray properties to those of other similar very late-type stars. Results: We clearly detected 1RXS J115928.5-524717 at soft X-ray energies in all EPIC detectors. Only minor variability was present during the observation and we attr

  50. Massimo Giovannini

    Stochastic backgrounds or relic gravitons, if ever detected, will constitute a prima facie evidence of physical processes taking place during the earliest stages of the evolution of the plasma. The essentials of the stochastic backgrounds of relic gravitons are hereby introduced and reviewed. The pivotal observables customarily employed to infer the properti

  51. Claudius Gros

    All self-active living beings need to solve the motivational problem: The question what to do at any moment of their live. For humans and non-human animals at least two distinct layers of motivational drives are known, the primary needs for survival and the emotional drives leading to a wide range of sophisticated strategies, such as explorative learning and

  52. F. Dutka, M. Napiorkowski

    We investigate liquid layers adsorbed at spherical and corrugated cylindrical substrates. The effective Hamiltonians for the liquid-gas interfaces fluctuating in the presence of such curved substrates are derived via the mean-field density functional theory. Their structure is compared with the Helfrich Hamiltonian which is parametrized by the bending and Ga

  53. H. -T. Ding, O. Kaczmarek, F. Karsch, H. Satz

    We present an operational approach to address the in-medium behavior of charmonium and analyze the reliability of maximum entropy method (MEM). We study the dependences of the ratio of correlators to the reconstructed one and the free one on the resonance's width and the continuum's threshold. Furthermore, we discuss the issue of the default model de

  54. Cafer Ay, Jean-Marc Richard, J. Hyam Rubinstein

    The linear potential binding a quark and an antiquark in mesons is generalized to baryons and multiquark configurations as the minimal length of flux tubes neutralizing the color, in units of the string tension. For tetraquark systems, i.e., two quarks and two antiquarks, this involves the two possible quark--antiquark pairings, and the Steiner tree linking

  55. Levente Tapaszto, Gergely Dobrik, Peter Nemes-Incze, Gabor Vertesy

    Mechanically exfoliated graphene layers deposited on SiO2 substrate were irradiated with Ar+ ions in order to experimentally study the effect of atomic scale defects and disorder on the low-energy electronic structure of graphene. The irradiated samples were investigated by scanning tunneling microscopy and spectroscopy measurements, which reveal that defect

  56. Nisha Yadav, Hrishikesh Joglekar, Rajesh P. N. Rao, M. N. Vahia

    The Indus script is one of the major undeciphered scripts of the ancient world. The small size of the corpus, the absence of bilingual texts, and the lack of definite knowledge of the underlying language has frustrated efforts at decipherment since the discovery of the remains of the Indus civilisation. Recently, some researchers have questioned the premise

  57. E. Voutier

    The Generalized Parton Distributions (GPDs) are the appropriate framework for a universal description of the partonic structure of the nucleon. They characterize the dynamics of quarks and gluons inside the nucleon and consequently contain information about the spin of the nucleon. The current experimental knowledge about GPDs is reviewed with the emphasis o

  58. Fatemeh Mohammadi, Somayeh Moradi

    For an unmixed bipartite graph $G$ we consider the lattice of vertex covers $\mathcal{L}_G$ and compute depth, projective dimension and extremal Betti-numbers of $R/I(G)$ in terms of this lattice.

  59. Walter Bergweiler, Janina Kotus

    The escaping set I(f) of a transcendental meromorphic function f consists of all points which tend to infinity under iteration. The Eremenko-Lyubich class B consists of all transcendental meromorphic functions for which the set of finite critical and asymptotic values of f is bounded. It is shown that if f is in B and of finite order of growth, if infinity i

  60. Eduardo Bravo, Domingo Garcia-Senz, Ruben M. Cabezon, Inmaculada Dominguez

    Observational evidences point to a common explosion mechanism of Type Ia supernovae based on a delayed detonation of a white dwarf. However, all attempts to find a convincing ignition mechanism based on a delayed detonation in a destabilized, expanding, white dwarf have been elusive so far. One of the possibilities that has been invoked is that an inefficien

  61. Guido Gentile

    We consider a class of ordinary differential equations describing one-dimensional systems with a quasi-periodic forcing term and in the presence of large damping. We discuss the conditions to be assumed on the mechanical force and the forcing term for the existence of quasi-periodic solutions which have the same frequency vector as the forcing.

  62. Eduardo Bravo, Domingo Garcia-Senz

    Observational evidences point to a common explosion mechanism of Type Ia supernovae based on a delayed detonation of a white dwarf. Although several scenarios have been proposed and explored by means of one, two, and three-dimensional simulations, the key point still is the understanding of the conditions under which a stable detonation can form in a destabi

  63. Wendell H. Fleming, Hidehiro Kaise, Shuenn-Jyi Sheu

    In the Maslov idempotent probability calculus, expectations of random variables are defined so as to be linear with respect to max-plus addition and scalar multiplication. This paper considers control problems in which the objective is to minimize the max-plus expectation of some max-plus additive running cost. Such problems arise naturally as limits of some

  64. N. Tsoneva, H. Lenske

    We present recent investigations on dipole and quadrupole excitations in spherical skin nuclei, particular exploring their connection to the thickness of the neutron skin. Our theoretical method relies on density functional theory, which provides us with a proper link between nuclear many-body theory of the nuclear ground state and its phenomenological descr

  65. Wilberd van der Kallen

    Friedrich Knop has given an example of a polynomial algebra A in characteristic two with an unusual SL_2 action. We exhibit a nontrivial class in H^1(SL_2,A), not detected by Frobenius kernels.

  66. Zhao-Ming Gan, Ding-Xiong Wang, Wei-Hua Lei

    We propose a model of magnetic connection (MC) of a black hole with its surrounding accretion disc based on large-scale magnetic field. The MC gives rise to transport of energy and angular momentum between the black hole and the disc, and the closed field lines pipe the hot matter evaporated from the disc, and shape it in the corona above the disc to form a

  67. Young-Sea Huang

    Based on the invariance of the phase of waves, plane waves was shown to propagate with negative frequencies in a medium which moves at superluminal speeds opposite to the propagation direction of plane waves. The validity of the invariance of the phase of plane waves was then called into question. A radical change of the conventional concept of plane waves i

  68. Tien-Cuong Dinh, Nessim Sibony

    Let f be a non-invertible holomorphic endomorphism of the complex projective space P^k, f^n its iterate of order n and μthe equilibrium measure of f. We estimate the speed of convergence in the following known result. If a is a Zariski generic point in P^k, the probability measures, equidistributed on the preimages of a under f^n, converge to μas n goes to i

  69. J. Buitrago

    By describing the dynamical evolution of a test charged particle in the presence of an electromagnetic field as a succession of infinitesimal Lorentz boosts and rotations it is possible to obtain the Lorentz Force of Electrodynamics. A consequence of this derivation at the classical level is that, given the existence of electric and magnetic fields, the form

  70. Wenzhuo Tang, Bin Luo, Yu Liu, Hong Guo

    The slow light effects of an amplitude modulated Gaussian (AMG) pulse in a cesium atomic vapor are presented. In a single-$Λ$ type electromagnetically induced transparency (EIT) medium, more severe distortion is observed for an AMG pulse than a Gaussian one. Using Fourier spectrum analysis, we find that the distortion, as well as the loss, is dominantly caus

  71. Pierre R. Bertrand, Gilles Teyssière, Gil Boudet, Alain Chamoux

    We propose a new method for estimating the change-points of heart rate in the orthosympathetic and parasympathetic bands, based on the wavelet transform in the complex domain and the study of the change-points in the moments of the modulus of these wavelet transforms. We observe change-points in the distribution for both bands.

  72. Ivana Agnolin, Jean-Noël Roux, Pascal Massaad, Xiaoping Jia

    Numerical simulations are used to investigate the origins of the different wave velocities measured in dense granular samples assembled with different methods. Glass bead packings are prepared in the lab either by pouring and vibrating the dry material in a container, or by mixing with a very small amount of a viscous lubricant. Lubricated samples, although

  73. Victor Guillemin, Thierry Paul

    In this paper we explore the connection between semi-classical and quantum Birkhoff canonical forms (BCF) for Schrodinger operators. In particular we give a "non-symbolic" operator theoretic derivation of the quantum Birkhoff canonical form and provide an explicit recipe for expressing the quantum BCF in terms of the semi-classical BCF.

  74. Thierry Paul

    We present several recent results concerning the transition between quantum and classical mechanics, in the situation where the underlying dynamical system has an hyperbolic behaviour. The special role of invariant manifolds will be emphasized, and the long time evolution will show how the quantum non-determinism and the classical chaotic sensitivity to init

  75. Christophe Cheverry, Isabelle Gallagher, Thierry Paul, Laure Saint-Raymond

    Waves associated to large scale oceanic motions are gravity waves (Poincaré waves which disperse fast) and quasigeostrophic waves (Rossby waves). In this Note, we show by semiclassical arguments, that Rossby waves can be trapped and we characterize the corresponding initial conditions.

  76. Victor Alexandrov

    We prove that the Dehn invariants of any Bricard octahedron remain constant during the flex and that the Strong Bellows Conjecture holds true for the Steffen flexible polyhedron.

  77. Adom Giffin

    In this thesis we start by providing some detail regarding how we arrived at our present understanding of probabilities and how we manipulate them - the product and addition rules by Cox. We also discuss the modern view of entropy and how it relates to known entropies such as the thermodynamic entropy and the information entropy. Next, we show that Skilling&

  78. Shijun Liao

    In this paper a new concept, namely the critical predictable time $T_c$, is introduced to give a more precise description of computed chaotic solutions of nonlinear differential equations: it is suggested that computed chaotic solutions are unreliable and doubtable when $ t > T_c$. This provides us a strategy to detect reliable solution from a given computed

  79. S. R. Souza, B. V. Carlson, R. Donangelo, W. G. Lynch

    The Statistical Multifragmentation Model is modified to incorporate the Helmholtz free energies calculated in the finite temperature Thomas-Fermi approximation using Skyrme effective interactions. In this formulation, the density of the fragments at the freeze-out configuration corresponds to the equilibrium value obtained in the Thomas-Fermi approximation a

  80. S. Albeverio, Sh. A. Ayupov, K. K. Kudaybergenov, B. O. Nurjanov

    The paper is devoted to local derivations on the algebra $S(\mathcal{M},τ)$ of $τ$-measurable operators affiliated with a von Neumann algebra $\mathcal{M}$ and a faithful normal semi-finite trace $τ.$ We prove that every local derivation on $S(\mathcal{M},τ)$ which is continuous in the measure topology, is in fact a derivation. In the particular case of type

  81. Yusuke Shuto, Shuu'ichirou Yamamoto, Satoshi Sugahara

    The authors proposed and computationally analyzed nonvolatile static random access memory (NV-SRAM) architecture using metal-oxide-semiconductor field-effect transistor (MOSFET) type of spin-transistors referred to as pseudo-spin-MOSFET (PS-MOSFET). PS-MOSFET is a new circuit approach to reproduce the functions of spin-transistors, based on recently progress

  82. Moira Chas, Anthony Phillips

    The minimum number of self-intersection points for members of a free homotopy class of curves on the punctured torus is bounded above in terms of the number L of letters required for a minimal description of the class in terms of the generators of the fundamental group and their inverses: it is less than or equal to (L-2)^2/4 if L is even, and (L-1)(L-3)/4 i

  83. Cesim K. Dumlu

    For Schwinger pair production with background electric fields varying only in time, it is shown that the quantum kinetic approach, based on the quantum Vlasov equation, and the quantum mechanical scattering approach, are completely equivalent. This different perspective on the quantum kinetic approach suggests new approximation methods, which are tested in d

  84. Yasushi Hotta, Teruo Kanki, Naoki Asakawa, Hitoshi Tabata

    We have investigated cooperative dynamics of an artificial stochastic resonant system, which is a recurrent ring connection of neuron-like signal transducers (NST) based on stochastic resonance (SR), using electronic circuit experiments. The ring showed quasi-periodic, tunable oscillation driven by only noise. An oscillation coherently amplified by noise dem

  85. Naoki Asakawa, Yasushi Hotta, Teruo Kanki, Hitoshi Tabata

    Problems with artificial neural networks originate from their deterministic nature and inevitable prior learnings, resulting in inadequate adaptability against unpredictable, abrupt environmental change. Here we show that a stochastically excitable threshold unit can be utilized by these systems to partially overcome the environmental change. Using an excita

  86. M. Kino, N. Kawakatu, H. Ito, H. Nagai

    Gamma-ray emission from cocoons of young radio galaxies is predicted. Considering the process of adiabatic injection of the shock dissipation energy and mass of the relativistic jet into the cocoon, we find that the thermal electron temperature of the cocoon is typically predicted to be of the order of $\sim$ MeV, and is determined only by the bulk Lorentz f

  87. F. Feng, J. P. Ma, Q. Wang

    The k_T-factorization has been widely used for exclusive decays of B-mesons. In this factorization the pertubative coefficients are extracted from scattering of off-shell partons. Because the off-shellness of partons the extracted pertubative coefficients in general are not gauge-invariant. We show that these perturbative coefficients contain gauge-dependent

  88. M. Baker

    We propose magnetic SU(N) pure gauge theory as an effective field theory describing the long distance nonperturbative magnetic response of the deconfined phase of Yang-Mills theory. The magnetic non-Abelian Lagrangian, unlike that of electrodynamics where there is exact electromagnetic duality, is not known explicitly, but here we regard the magnetic SU(N) Y

  89. David Reeb

    Newton's gravitational constant is shown to be a running coupling constant, much like the familiar running gauge couplings of the Standard Model. This implies that, in models with appropriate particle content, the true Planck scale, i.e. the scale at which quantum gravity effects become important, can have a value different from 10^19 GeV, which would be

  90. Slavik Jablan, Ljiljana Radovic

    For families of knots and links given in Conway notation we compute lower maximal and upper minimal bound of hyperbolic volume by using source links and augmented links.

  91. Robert Wagner

    Some models for quantum gravity (QG) violate Lorentz invariance and predict an energy dependence of the speed of light, leading to a dispersion of high-energy gamma-ray signals that travel over cosmological distances. Limits on the dispersion from short-duration substructures observed in gamma-rays emitted by gamma-ray bursts (GRBs) at cosmological distances

  92. Patrick Meade, Michele Papucci, Tomer Volansky

    We construct a Dark Matter (DM) annihilation module that can encompass the predictions from a wide array of models built to explain the recently reported PAMELA and ATIC/PPB-BETS excesses. We present a detailed analysis of the injection spectrums for DM annihilation and quantitatively demonstrate effects that have previously not been included from the partic

  93. Andrew Terekhov

    A parallel algorithm for solving a series of matrix equations with a constant tridiagonal matrix and different right-hand sides is proposed and studied. The process of solving the problem is represented in two steps. The first preliminary step is fixing some rows of the inverse matrix of SLAEs. The second step consists in calculating solutions for all right-

  94. F. E. Becerra, R. T. Willis, S. L. Rolston, L. A. Orozco

    We demonstrate a technique to lock the frequency of a laser to a transition between two excited states in Rb vapor in the presence of a weak magnetic field. We use a ladder configuration from specific hyperfine sublevels of the 5S 1/2, 5P 3/2, and 5D 5/2 levels. This atomic configuration can show Electromagnetically Induced Transparency and Absorption proces

  95. Tania Regimbau, Scott A. Hughes

    Increasing the sensitivity of a gravitational-wave (GW) detector improves our ability to measure the characteristics of detected sources. It also increases the number of weak signals that contribute to the data. Because GW detectors have nearly all-sky sensitivity, they can be subject to a confusion limit: Many sources which cannot be distinguished may be me

  96. Eiji Kaneshita, Tsuneyoshi Nakayama

    We present the quantitative interpretation for the glass-like behavior of thermal conductivities $\kappa(T)$ for type-I clathrate compounds involving off-centered guest ions. It is shown that the dipole-dipole interaction generated in cage/guest-ion systems is crucial to reproduce the characteristics of thermal conductivities for these symmetry-broken clathr

  97. Peter Orland, Jing Xiao

    Under a rescaling of longitudinal coordinates $x^{0,3}$ by a factor $λ$ which is taken to zero, the classical QCD action simplifies dramatically. This is the high-energy limit, as $λ$ is of order $s^{-1/2}$, where $s$ is the center-of-mass energy squared of a hadronic collision. We find the quantum corrections to the rescaled action at one loop, in particula

  98. B. Pittman-Polletta

    This paper deals with well-known higher-order generalizations of Hankel operators. We show that higher-order Hankel operators can be written explicitly as linear differential operators, and give the exact form of these differential operators. We also intoduce a novel Lie-theoretic perspective from which to study higher-order Hankel operators.

  99. Roberto Casadio, Sergio Fabi, Benjamin Harms

    In this paper we present the results of our analysis of the growth and decay of black holes possibly produced at the Large Hadron Collider, based on our previous study of black holes in the context of the warped brane-world scenario. The black hole mass accretion and decay is obtained as a function of time, and the maximum black hole mass is obtained as a fu

  100. Stefan K. Baur, Sourish Basu, Theja N. De Silva, Erich J. Mueller

    We present a series of theoretical studies of the boundary between a superfluid and normal region in a partially polarized gas of strongly interacting fermions. We present mean-field estimates of the surface energy in this boundary as a function of temperature and scattering length. We discuss the structure of the domain wall, and use a previously introduced