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July 2006 arXiv papers — page 15

Showing 1,4011,500 of 4,443 papers

  1. G Ambika, K Ambika

    We discuss the possibility of simultaneous and sequential synchronisation in vertical and horizontal arrays of unidirectionally coupled discrete systems. This is realized for the specific case of two dimensional Gumowski-Mira maps. The synchronised state can be periodic,thereby bringing in control of chaos, or chaotic for carefully chosen parameters of the p

  2. Jonathan C. Mattingly, Toufic Suidan, Eric Vanden-Eijnden

    We analyze a class of linear shell models subject to stochastic forcing in finitely many degrees of freedom. The unforced systems considered formally conserve energy. Despite being formally conservative, we show that these dynamical systems support dissipative solutions (suitably defined) and, as a result, may admit unique (statistical) steady states when th

  3. Erick Herbin, Ely Merzbach

    We prove that a set-indexed process is a set-indexed fractional Brownian motion if and only if its projections on all the increasing paths are one-parameter time changed fractional Brownian motions. As an application, we present an integral representation for such processes.

  4. T. Bloom, N. Levenberg, Yu. Lyubarskii

    For a regular, compact, polynomially convex circled set K in C^2, we construct a sequence of pairs {P_n,Q_n} of homogeneous polynomials in two variables with deg P_n = deg Q_n = n such that the sets K_n: = {(z,w) \in C^2 : |P_n(z,w)| \leq 1, |Q_n(z,w)| \leq 1} approximate K and the normalized counting measures {μ_n} associated to the finite set {P_n = Q_n =

  5. Francis Filbet, Clément Mouhot, Lorenzo Pareschi

    In [C. Mouhot and L. Pareschi, "Fast algorithms for computing the Boltzmann collision operator," Math. Comp., to appear; C. Mouhot and L. Pareschi, C. R. Math. Acad. Sci. Paris, 339 (2004), pp. 71-76], fast deterministic algorithms based on spectral methods were derived for the Boltzmann collision operator for a class of interactions including the ha

  6. Aly A. Tamim, Nabil L. Youssef

    By a Randers' structure on a manifold $M$ we mean a Finsler structure $L^*=L+α$, where $L$ is a Riemannian structure and $α$ is a 1-form on $M$. This structure was first introduced by Randers ~\cite{[8]} from the standpoint of general relativity. In this paper, we replace $L$ by a Finsler structure, calling the resulting manifold a generalized Randers ma

  7. J. S. Milne

    In April, 2006, Kontsevich asked me whether the category of motives over F_p (p prime) has a fibre functor over a number field of finite degree since he had a conjecture that more-or-less implied this. This article is my response. Unfortunately, since the results are generally negative or inconclusive, they are of little interest except perhaps for the quest

  8. N. Brodskiy, J. Dydak, A. Mitra

    The main results of the paper are: \begin{Prop}\label{GenSvarc-Milnor} A group $G$ acting coarsely on a coarse space $(X,\CC)$ induces a coarse equivalence $g\to g\cdot x_0$ from $G$ to $X$ for any $x_0\in X$. \end{Prop} Theorem: \label{GenGromovThm} Two coarse structures $\CC_1$ and $\CC_2$ on the same set $X$ are equivalent if the following conditions are

  9. Vikram Mehta, Christian Pauly

    Let $X$ be a smooth projective curve of genus $g \geq 2$ defined over an algebraically closed field $k$ of characteristic $p>0$. Given a semistable vector bundle $E$ over $X$, we show that its direct image $F\_*E$ under the Frobenius map $F$ of $X$ is again semistable. We deduce a numerical characterization of the stable rank-$p$ vector bundles $F\_*L$, wher

  10. Benjamin Steinberg

    We give a partial solution a question of Grigorchuk, Nekrashevych, Sushchanskii and Šunik by giving an algorithm to test whether a finite state element of an infinite iterated (permutational) wreath product $\hat G = \mathbb Z/k\mathbb Z\wr \mathbb Z/k\mathbb Z\wr \mathbb Z/k\mathbb Z\wr >...$ of cyclic groups of order $n$ acts spherically transitively. We c

  11. Georg Hofmann

    We investigate which Weyl groups have a Coxeter presentation and which of them at least have the presentation by conjugation with respect to their root system. For most concepts of root systems the Weyl group has both. In the context of extended affine root systems (EARS) there is a small subclass allowing a Coxeter presentation of the Weyl group and a large

  12. H. Lamba, J. C. Mattingly, A. M. Stuart

    The understanding of adaptive algorithms for SDEs is an open area where many issues related to both convergence and stability (long time behaviour) of algorithms are unresolved. This paper considers a very simple adaptive algorithm, based on controlling only the drift component of a time-step. Both convergence and stability are studied. The primary issue in

  13. Carlos Castano-Bernard

    Let C be the image of a canonical embedding C of the Atkin-Lehner quotient X+0(N) associated to the Fricke involution wN. In this note we exhibit some relations among the rational points of C. For each g = 3 (resp. the first g = 4) curve C we found that there are one or more lines (resp. planes) in projectie space whose intersection with C consists entirely

  14. Andrey O. Matveev

    Antichains of a finite bounded poset are assigned antichains playing a role analogous to that played by blockers in the Boolean lattice of all subsets of a finite set. Some properties of lattices of generalized blockers are discussed.

  15. C. Villavicencio, C. A. A. de Carvalho

    We describe the Feynman rules for the construction of the Dimensionally Reduced Action (DRA) for a phi^4 field theory, as well as rules for the construction of the connected Green functions and the Dimensionally Reduced Effective Action (DREA), the effective action obtained from the DRA. Two and four-point connected Green functions are calculated to illustra

  16. J. Charles, A. Hocker, H. Lacker, F. R. Le Diberder

    In Bayesian statistics, one's prior beliefs about underlying model parameters are revised with the information content of observed data from which, using Bayes' rule, a posterior belief is obtained. A non-trivial example taken from the isospin analysis of B-->PP (P = pi or rho) decays in heavy-flavor physics is chosen to illustrate the effect of the

  17. Ulrich Nierste

    I first discuss the phenomenology of a^q_fs (q=d,s), which is the CP asymmetry in flavour-specific B_q decays such as B_d -> X l^+ nu-bar_l or B_s -> D_s^- pi^+. a^q_fs can be obtained from the time evolution of any untagged B_q decay. Then I present recently calculated next-to-leading-order QCD corrections to a_fs^q, which reduce the renormalisation scheme

  18. Huey-Wen Lin, Shigemi Ohta, Amarjit Soni, Norikazu Yamada

    We report a study describing the charm quark by a domain-wall fermion (DWF) in lattice quantum chromodynamics (QCD). Our study uses a quenched gauge ensemble with the DBW2 rectangle-improved gauge action at a lattice cutoff of $a^{-1} \sim 3$ GeV. We calculate masses of heavy-light (charmed) and heavy-heavy (charmonium) mesons with spin-parity $J^P = 0^\mp$

  19. The BABAR Collaboration, B. Aubert

    We present a study of two states decaying to Lambda_c^+K^-pi^+ using the BaBar detector at the SLAC PEP-II asymmetric-energy e^+e^- storage rings. We use an integrated luminosity of 288.5 fb^{-1} collected at the center-of-mass energy sqrt{s} = 10.58 GeV, near the peak of the Upsilon(4S) resonance, plus 27.2 fb^{-1} collected approximately 40 MeV below this

  20. Johannes M. Bauer

    Rare B decays permit stringent tests of the Standard Model and allow searches for new physics. Several rare radiative-decay studies of the B meson from the BaBar collaboration are described. So far no sign for new physics was discovered.

  21. Kazuhiro Yamamoto, Shinji Miyoki, Takashi Uchiyama, Hideki Ishitsuka

    We have measured the mechanical loss of a dielectric multilayer reflective coating (ion-beam sputtered SiO$_2$ and Ta$_2$O$_5$) in cooled mirrors. The loss was nearly independent of the temperature (4 K $\sim$ 300 K), frequency, optical loss, and stress caused by the coating, and the details of the manufacturing processes. The loss angle was $(4 \sim 6) \tim

  22. Xin Han, Kazuo Iwama, Guochuan Zhang

    In this paper, we study the 3D strip packing problem in which we are given a list of 3-dimensional boxes and required to pack all of them into a 3-dimensional strip with length 1 and width 1 and unlimited height to minimize the height used. Our results are below: i) we give an approximation algorithm with asymptotic worst-case ratio 1.69103, which improves t

  23. A. E. Allahverdyan, Th. M. Nieuwenhuizen

    The minimal work principle asserts that work done on a thermally isolated equilibrium system, is minimal for the slowest (adiabatic) realization of a given process. This principle, one of the formulations of the second law, is operationally well-defined for any finite (few particle) Hamiltonian system. Within classical Hamiltonian mechanics, we show that the

  24. B Lorenz, O Perner, J Eckert, C W Chu

    Nanocrystalline MgB$_2$ produced by mechanical alloying has been shown to exhibit enhanced superconducting properties such as increased pinning and higher critical currents. However, the effects of the synthesis process on the intrinsic superconducting properties have not been addressed yet. We have investigated the superconducting gap structure of nanocryst

  25. Hyun-Tak Kim, Bong-Jun Kim, Yong Wook Lee, Byung-Gyu Chae

    For inhomogeneous high-T_c superconductors, hole-driven metal-insulator transition (MIT) theory explains that the gradual increase of conductivity with increasing hole doping is due to inhomogeneity with the local Mott system undergoing the first-order MIT and the local non-Mott system. For VO_2, a monoclinic and correlated metal (MCM) phase showing the line

  26. P. Zubko, D. J. Jung, J. F. Scott

    The effects of space charges on hysteresis loops and field distributions in ferroelectrics have been investigated numerically using the phenomenological Landau-Ginzburg-Devonshire theory. Cases with the ferroelectric fully and partially depleted have been considered. In general, increasing the number of charged impurities results in a lowering of the polariz

  27. C. H. Wang, X. H. Chen, G. Wu, T. Wu

    Angular-dependent in-plane magnetoresistance (AMR) for single crystal $Na_{0.34}(H_3O)_{0.15}CoO_2$ with charge ordering is studied systematically. The anisotropic magnetoresistance shows a twofold symmetry at high temperature with rotating H in the Co-O plane, while a sixfold symmetry below a certain temperature ($T_ρ$). At $T_ρ$, the symmetry of AMR change

  28. L. -X. Zhang, D. V. Melnikov, J. -P. Leburton

    The charge stability diagram for two coupled quantum dots containing up to two electrons is computed in magnetic fields. One- and two-particle Schroedinger equations are solved by exact diagonalization to obtain the chemical potentials and exchange energy in these systems. By analyzing the chemical potentials variation with external biases and magnetic field

  29. John Ray, Gerry Gilmore

    We reconsider the description of a solar eclipse in the Coptic ostracon in the Egyptian museum, Turin, confirming its identification with the solar eclipse of 10 march 601. This provides one of very few fixed dates in Coptic chronology. We comment on the rarity of such descriptions.

  30. Robert A. Gruendl, Martin A. Guerrero, You-Hua Chu, Rosa M. Williams

    We have obtained X-ray observations of the bipolar planetary nebulae (PNe) NGC 2346 and NGC 7026 with XMM-Newton. These observations detected diffuse X-ray emission from NGC 7026 but not from NGC 2346. The X-ray emission from NGC 7026 appears to be confined within the bipolar lobes of the PN and has spectral properties suggesting a thermal plasma emitting at

  31. Wei Zhu

    In this paper, we show that the metric space Q is a positively-curved space (PC-space) in the sense of Alexandrov. We also discuss some issues like metric tangent cone and exponential map of Q. Then we give a stratification of this metric space according to the signature of points in Q. Some properties of this stratification are shown. The second part of thi

  32. M. A. Betemps, M. B. Gay Ducati, E. G. de Oliveira, 1 High Energy Physics Phenomenology Group

    The dilepton production at backward rapidities in $pAu$ and $pp$ collisions at RHIC and LHC energies is investigated in the dipole approach. The results are shown through the nuclear modification ratio $R_{pA}$ considering transverse momentum and rapidity spectra. The dilepton modification ratio presents interesting behavior at the backward rapidities when c

  33. Matthew T. Glossop, Kevin Ingersent

    The quantum phase transition between paramagnetic and antiferromagnetic phases of the Kondo lattice model with Ising anisotropy in the intersite exchange is studied within the framework of extended dynamical mean-field theory. Nonperturbative numerical solutions at zero temperature point to a continuous transition for both two- and three-dimensional magnetis

  34. S. S. Kancharla, E. Dagotto

    We investigate the ground state phase diagram of the half-filled repulsive Hubbard model in two dimensions in the presence of a staggered potential $Δ$, the so-called ionic Hubbard model, using cluster dynamical mean field theory. We find that for large Coulomb repulsion, $U\gg Δ$, the system is a Mott insulator (MI). For weak to intermediate values of $Δ$,

  35. Benson Farb, Michael Handel

    Let $\Out(F_n)$ denote the outer automorphism group of the free group $F_n$ with $n>3$. We prove that for any finite index subgroup $Γ<\Out(F_n)$, the group $\Aut(Γ)$ is isomorphic to the normalizer of $Γ$ in $\Out(F_n)$. We prove that $Γ$ is {\em co-Hopfian} : every injective homomorphism $Γ\to Γ$ is surjective. Finally, we prove that the abstract commensur

  36. Alioscia Hamma, Daniel A. Lidar

    Topological order characterizes those phases of matter that defy a description in terms of symmetry and cannot be distinguished in terms local order parameters. This type of order plays a key role in the theory of the fractional quantum Hall effect, as well as in topological quantum information processing. Here we show that a system of n spins forming a latt

  37. Jingshan Zhang, B. I. Shklovskii

    Translocation of a single stranded DNA (ssDNA) through an alpha-hemolysin channel in a lipid membrane driven by applied transmembrane voltage V was extensively studied recently. While the bare charge of the ssDNA piece inside the channel is approximately 12 (in units of electron charge) measurements of different effective charges resulted in values between o

  38. Ilya A. Gruzberg

    Conformally-invariant curves that appear at critical points in two-dimensional statistical mechanics systems, and their fractal geometry have received a lot of attention in recent years. On the one hand, Schramm has invented a new rigorous as well as practical calculational approach to critical curves, based on a beautiful unification of conformal maps and s

  39. W. Liu, C. M. Ko, B. W. Zhang

    Quark and gluon jets traversing through a quark-gluon plasma not only lose their energies but also can undergo flavor conversions. The conversion rates via the elastic $q(\bar q)g\to gq(\bar q)$ and the inelastic $q\bar q\leftrightarrow gg$ scatterings are evaluated in the lowest order in QCD. Including both jet energy loss and conversions in the expanding q

  40. David Milovich

    We construct a path-connected homogenous compactum with cellularity 2^omega that is not homeomorphic to any product of dyadic compacta and first countable compacta. We also prove some closure properties for classes of spaces defined by various connectifiability conditions. One application is that every infinite product of infinite topological sums of T_i spa

  41. Edward Lyman, Daniel M. Zuckerman

    Although atomistic simulations of proteins and other biological systems are approaching microsecond timescales, the quality of trajectories has remained difficult to assess. Such assessment is critical not only for establishing the relevance of any individual simulation but also in the extremely active field of developing computational methods. Here we map t

  42. J. M. Drummond, J. Henn, V. A. Smirnov, E. Sokatchev

    We propose an iterative procedure for constructing classes of off-shell four-point conformal integrals which are identical. The proof of the identity is based on the conformal properties of a subintegral common for the whole class. The simplest example are the so-called `triple scalar box&#39; and `tennis court&#39; integrals. In this case we also give an in

  43. Eduardo R. Mucciolo, Caio H. Lewenkopf, Leonid I. Glazman

    We establish relations between the statistics of g factors and the fluctuations of energy in metallic nanoparticles where spin-orbit coupling is present. These relations assume that the electron dynamics in the grain is chaotic. The expressions we provide connect the second moment of the g factor to the root-mean square ``level velocity&#39;&#39; (the deriva

  44. G. W. Bruhn

    This note corrects an erroneous article by M.W. Evans on his GCUFT theory which he took over in his GCUFT book. Due to Evans&#39; bad habit of suppressing seemingly unimportant indices type match errors occur that cannot be removed. In addition some further errors of that article/book chapter are pointed out.

  45. Manjari Bagchi, Rachid Ouyed, Jan Staff, Subharthi Ray

    The effects of temperature on strange stars are studied and it is found that the maximum mass of the star decreases with the increase of temperature since at high temperatures the equations of state become softer. Moreover, if the temperature of a strange star increases, keeping its baryon number fixed, its gravitational mass increases and radius decreases.

  46. D. Boyanovsky, H. J. de Vega, N. G. Sanchez

    We investigate the issue of initial conditions of curvature and tensor perturba- tions at the beginning of slow roll inflation and their effect on the power spectra. Renormalizability and small back reaction constrain the high k behavior of the Bogoliubov coefficients that define these initial conditions.We introduce a transfer function D(k) which encodes th

  47. D. Boyanovsky, H. J. de Vega, N. G. Sanchez

    Within the effective field theory of inflation, an initialization of the classical dynamics of the inflaton with approximate equipartition between the kinetic and potential energy of the inflaton leads to a brief fast roll stage that precedes the slow roll regime. The fast roll stage leads to an attractive potential in the wave equations for the mode functio

  48. Manolo Eminenti, Gabriele La Nave, Carlo Mantegazza

    We discuss some classification results for Ricci solitons, that is, self similar solutions of the Ricci Flow. Some simple proofs of known results will be presented. In detail, we will take the equation point of view, trying to avoid the tools provided by considering the dynamic properties of the Ricci flow.

  49. Matteo Luca Ruggiero, Lorenzo Iorio

    In this paper we study the effects of $f(R)$ Theories of Gravity on Solar System gravitational tests. In particular, starting from an exact solution of the field equation in vacuum, in the Palatini formalism, we work out the effects that the modifications to the Newtonian potential would induce on the Keplerian orbital elements of the Solar System planets, a

  50. P. Colangelo, F. De Fazio, S. Nicotri

    We analyze the recently discovered $D_{sJ}(2860)$ meson using arguments based on the heavy quark expansion together with the experimental observations. We consider the possible quantum number assignments, arguing that the interpretation of the meson as the $J^P=3^-$ $c \bar s$ state is favoured.

  51. Kwabena Doku-Amponsah, Peter Mörters

    For any finite colored graph we define the empirical neighborhood measure, which counts the number of vertices of a given color connected to a given number of vertices of each color, and the empirical pair measure, which counts the number of edges connecting each pair of colors. For a class of models of sparse colored random graphs, we prove large deviation

  52. Jacob Rasmussen

    We study the relationship between the HOMFLY and sl(N) knot homologies introduced by Khovanov and Rozansky. For each N>0, we show there is a spectral sequence which starts at the HOMFLY homology and converges to the sl(N) homology. As an application, we determine the KR-homology of knots with 9 crossings or fewer.

  53. H. Bea, M. Bibes, S. Cherifi, F. Nolting

    We report on the functionalization of multiferroic BiFeO3 epitaxial films for spintronics. A first example is provided by the use of ultrathin layers of BiFeO3 as tunnel barriers in magnetic tunnel junctions with La2/3Sr1/3MnO3 and Co electrodes. In such structures, a positive tunnel magnetoresistance up to 30% is obtained at low temperature. A second exampl

  54. Giuseppe Burgio, Marcel Fuhrmann, Werner Kerler, Michael Mueller-Preussker

    We study the continuum limit of adjoint SU(2) LGT by means of a suppression term for Z2 monopoles. High barriers for tunnelling among different twist sectors are overcome through parallel tempering. Monopole condensation is used to study the deconfinement transition and the properties of the confined phase. Ergodicity in summing over all twist sectors allows

  55. T. Abete, E. Del Gado, D. Hellio Serughetti, L. de Arcangelis

    In chemical crosslinking of gelatin solutions, two different time scales affect the kinetics of the gel formation in the experiments. We complement the experimental study with Monte Carlo numerical simulations of a lattice model. This approach shows that the two characteristic time scales are related to the formation of single bonds crosslinker-chain and of

  56. Masaki Kawamura, Masato Okada

    We investigate dynamics of recurrent neural networks with correlated noise to analyze the noise&#39;s effect. The mechanism of correlated firing has been analyzed in various models, but its functional roles have not been discussed in sufficient detail. Aoyagi and Aoki have shown that the state transition of a network is invoked by synchronous spikes. We intr

  57. N. Chatillon, A. Pinzul

    We study the low-energy effects of space-time non-commutativity on light propagation in a background electromagnetic field. Contrary to some of the previous claims, we find no polarization rotation for vanishing time-space commutator $[\hat{x}^i,\hat{x}^0]= 0$, although dispersion relation is modified, allowing for propagation faster than the vacuum speed of

  58. S. Vogel, M. Bleicher

    In these proceedings we concentrate on the refeeding and rescattering probability of hadronic resonances. We discuss the probability to form resonances in binary baryon-meson or meson-meson collisions as a function of time for various resonances using a transport model approach (UrQMD). We give an estimate of the re-feeding probability using a simplified the

  59. L. S. Cederbaum, A. I. Streltsov, Y. B. Band, O. E. Alon

    It is shown that the density of two {\it initially independent} condensates which are allowed to expand and overlap can show interferences as a function of time due to interparticle interaction. Using many-body theory, explicit expressions for the density are given which are exact in the weak interaction limit. General working equations are discussed which r

  60. Michael A. Schmidt, Alexei Yu. Smirnov

    We consider a scenario for the Quark-Lepton Complementarity relations between mixing angles in which the bi-maximal mixing follows from the neutrino mass matrix. According to this scenario in the lowest order the angle θ_{12} is \sim 1σ(1.5 - 2^\circ) above the best fit point coinciding practically with the tri-bimaximal mixing prediction. Realization of thi

  61. Duiliu-Emanuel Diaconescu, Ron Donagi, Tony Pantev

    Let $Σ$ be a smooth projective complex curve and $\mathfrak{g}$ a simple Lie algebra of type ${\sf ADE}$ with associated adjoint group $G$. For a fixed pair $(Σ, \mathfrak{g})$, we construct a family of quasi-projective Calabi-Yau threefolds parameterized by the base of the Hitchin integrable system associated to $(Σ,\mathfrak{g})$. Our main result establish

  62. G Seregin

    A class of sufficient conditions of local regularity for suitable weak solutions to the nonstationary three-dimensional Navier-Stokes equations are discussed. The corresponding results are formulated in terms of functionals which are invariant with respect to the Navier-Stokes equations scaling. The famous Caffarelli-Kohn-Nirenberg condition is contained in

  63. David Hernandez

    In this paper we study minimal affinizations of representations of quantum groups (generalizations of Kirillov-Reshetikhin modules of quantum affine algebras introduced by Chari). We prove that all minimal affinizations in types A, B, G are special in the sense of monomials. Although this property is not satisfied in general, we also prove an analog property

  64. G Seregin

    We prove some estimates for suitable weak solutions to the non-stationary three-dimensional Navier-Stokes equations under assumptions that certain invariant functionals of the velocity are bounded.

  65. Marcus Ansorg, David Petroff

    We study two types of axially symmetric, stationary and asymptotically flat spacetimes using highly accurate numerical methods. The one type contains a black hole surrounded by a perfect fluid ring and the other a rigidly rotating disc of dust surrounded by such a ring. Both types of spacetime are regular everywhere (outside of the horizon in the case of the

  66. Natalia Kopteva, Gerald Williams

    Pride groups, or ``groups given by presentations in which each defining relator involves at most two types of generators&#39;&#39;, include Coxeter groups, Artin groups, triangles of groups, and Vinberg&#39;s groups defined by periodic paired relations. We show that every non-spherical Pride group that is not a triangle of groups satisfies the Tits alternati

  67. G. Miniutti, G. Ponti, M. Dadina, M. Cappi

    We report the XMM-Newton detection of a moderately bright X-ray source superimposed on the outer arms of the inactive spiral galaxy MCG-03-34-63 (z=0.0213). It is clearly offset from the nucleus (by about 19&#39;&#39;) but well within the D25 ellipse of the galaxy, just along its bar axis. The field has also been observed with the HST enabling us to compute

  68. Elisabetta Di Grezia, Giampiero Esposito, Gennaro Miele

    Recent work in the literature has studied the quantum-mechanical decay of a Schwarzschild-like black hole, formed by gravitational collapse, into almost-flat space-time and weak radiation at a very late time. The relevant quantum amplitudes have been evaluated for bosonic and fermionic fields, showing that no information is lost in collapse to a black hole.

  69. R. Harlander, P. Kant, L. Mihaila, M. Steinhauser

    Dimensional Reduction is applied to \qcd{} in order to compute various renormalization constants in the \drbar{} scheme at higher orders in perturbation theory. In particular, the $β$ function and the anomalous dimension of the quark masses are derived to three-loop order. Special emphasis is put on the proper treatment of the so-called $ε$-scalars and the a

  70. A. E. Shabad, V. V. Usov

    We describe the potential produced by a point electric charge placed into a constant magnetic field, so strong that the electron Larmour length is much shorter than its Compton length. The standard Coulomb law is modified due to the vacuum polarization by the external magnetic field. Only mode-2 photons mediate the static interaction. The corresponding vacuu

  71. Gabriella Böhm, Tomasz Brzezinski

    Properties of (most general) non-commutative torsors or A-B torsors are analysed. Starting with pre-torsors it is shown that they are equivalent to a certain class of Galois extensions of algebras by corings. It is shown that a class of faithfully flat pre-torsors induces equivalences between categories of comodules of associated corings. It is then proven t

  72. Chris Van Den Broeck, Anand S. Sengupta

    We study the phenomenological consequences of amplitude-corrected post-Newtonian (PN) gravitational waveforms, as opposed to the more commonly used restricted PN waveforms, for the quasi-circular, adiabatic inspiral of compact binary objects. In the case of initial detectors it has been shown that the use of amplitude-corrected waveforms for detection templa

  73. P. S. Howe, U. Lindstrom, L. Wulff

    A covariant version of the non-abelian Dirac-Born-Infeld-Myers action is presented. The non-abelian degrees of freedom are incorporated by adjoining to the (bosonic) worldvolume of the brane a number of anticommuting fermionic directions corresponding to boundary fermions in the string picture. The proposed action treats these variables as classical but can

  74. Daisuke Matsubayashi, Mikio Eto

    We study the Kondo effect in a quantum dot coupled to two noncollinear ferromagnetic leads. First, we study the spin splitting $δε=ε_{\downarrow}-ε_{\uparrow}$ of an energy level in the quantum dot by tunnel couplings to the ferromagnetic leads, using the Poor man&#39;s scaling method. The spin splitting takes place in an intermediate direction between magne

  75. Patrick Navez, Axel Pelster, Robert Graham

    We study the properties of a dilute Bose condensed gas at zero temperature in the presence of a strong random potential with arbitrary correlation length. Starting from the underlying Gross-Pitaevskii equation, we use the random phase approximation in order to get a closed integral equation for the averaged density distribution which allows to determine both

  76. David Hernandez

    The geometric small property (Borho-MacPherson) of projective morphisms implies a description of their singularities in terms of intersection homology. In this paper we solve the smallness problem raised by Nakajima (math.QA/0105173) for certain resolutions of quiver varieties (analogs of the Springer resolution) : for Kirillov-Reshetikhin modules of simply-

  77. UKQCD Collaboration, C. McNeile, C. Michael

    We review the theory that predicts that the decay constant of the excited light pseudo-scalar mesons are suppressed in the chiral limit relative to the pion decay constant. We compute the decay constant of the first excited pion ($π^\prime$) using unquenched QCD at a fixed lattice spacing with sea quarks of mass as low as a third the mass of the strange quar

  78. George Lazarides

    Supersymmetric Peccei-Quinn models which provide a suitable candidate for the curvaton field are studied. These models also solve the mu problem, while generating the Peccei-Quinn scale dynamically. The curvaton is a pseudo Nambu-Goldstone boson corresponding to an angular degree of freedom orthogonal to the axion. Its order parameter increases substantially

  79. Yutaka Sakamura, Yutaka Hosotani

    In the dynamical gauge-Higgs unification in the Randall-Sundrum warped spacetime, where the 4D Higgs field is unified with gauge fields and the electroweak symmetry is dynamically broken by the Hosotani mechanism, the trilinear couplings for WWZ, WWH, and ZZH, where H stands for the Higgs field, are evaluated. The latter two couplings are suppressed by a fac

  80. Laurent Baratchart, Jean-Baptiste Pomet

    We consider the problem of topological linearization of smooth (C infinity or real analytic) control systems, i.e. of their local equivalence to a linear controllable system via point-wise transformations on the state and the control (static feedback transformations) that are topological but not necessarily differentiable. We prove that local topological lin

  81. Gerhard W Bruhn

    Correcting a former proof of M.W. Evans it is shown that his O(3) hypothesis is not Lorentz invariant and hence no law of Physics.

  82. Henri-Hugues Fliche, Roland Triay

    The dynamical effect of the cosmological constant $Λ$ on a single spherical void evolving in a the universe is investigated within a non linear perturbation of Newton-Friedmann models. The void expands with a huge initial burst which freezes asymptotically with time up to matching Hubble flow. For $Ω_{\circ}\sim 0.3$, $Λ$-effect on the kinematics intervenes

  83. Sergio Mendes, Roger Plymen

    We investigate base change $C/R$ at the level of $K$-theory for the general linear group $GL(n,R)$. In the course of this study, we compute in detail the $C*$-algebra $K$-theory of this disconnected group. We investigate the interaction of base change with the Baum-Connes correspondence for $GL(n,R)$ and $GL(n,C)$. This article is the archimedean companion o

  84. Claudio Conti, Luca Angelani, Giancarlo Ruocco

    Using a 3D Finite-Difference Time-Domain parallel code, we report on the linear and nonlinear propagation of light pulses in a disordered assembly of scatterers, whose spatial distribution is generated by a Molecular Dynamics code; refractive index dispersion is also taken into account. We calculate the static and dynamical diffusion constant of light, while

  85. Abhas Mitra

    It is known that, for a static fluid sphere, the GeneralRelativistic (GR) Effective Mass Energy Density (EMD) appears to be (rho + 3 p), where rho is the bare mass density, p is the isotropic pressure, from a purely localized view point. But since there is no truly local definition of ``gravitational field&#39;&#39;, such a notion could actually be misleadin

  86. Mohammed Larbi Labbi

    The Weitzenböck curvature operators are the curvature terms of order zero that appear in the well known classical Weitzenböck formula. In this paper, we use the formalism of double forms to prove a simple formula for this operators and to study their geometric properties.

  87. Sezgin Aygun, Ismail Tarhan, Husnu Baysal

    This paper has been removed by arXiv administrators because it plagiarizes gr-qc/0603075 and others. This paper has excessive overlap with the following papers also written by the authors or their collaborators: gr-qc/0606080, gr-qc/0607126, gr-qc/0607109, gr-qc/0607110, and others.

  88. Syed A. Jafar, Shlomo Shamai

    We provide achievability as well as converse results for the degrees of freedom region of a MIMO $X$ channel, i.e., a system with two transmitters, two receivers, each equipped with multiple antennas, where independent messages need to be conveyed over fixed channels from each transmitter to each receiver. With M=1 antennas at each node, we find that the tot

  89. Cheng Li, Guinevere Kauffmann, Lan Wang, Simon D. M. White

    We have analyzed the clustering of ~ 90,000 narrow-line AGN drawn from the Data Release 4 (DR4) of the SDSS. We compute the cross-correlation between AGN and a reference sample of galaxies, and compare this to results for control samples of inactive galaxies matched simultaneously in redshift,stellar mass,concentration, velocity dispersion and the 4000A brea

  90. P. J. Forrester, N. E. Frankel, M. I. Makin

    An intensive study for both the weak coupling and strong coupling limits of the ground state properties of this classic system is presented. Detailed results for specific values of finite $N$ are given and from them results for general $N$ are determined. We focus on the density matrix and concomitantly its Fourier transform, the occupation numbers, along wi

  91. P. S. Bourdon, H. T. Williams

    Let N be a (large positive integer, let b > 1 be an integer relatively prime to N, and let r be the order of b modulo N. Finally, let QC be a quantum computer whose input register has the size specified in Shor&#39;s original description of his order-finding algorithm. We prove that when Shor&#39;s algorithm is implemented on QC, then the probability P of ob

  92. D. E. Feldman, Alexei Kitaev

    Fractionally charged quasiparticles in the quantum Hall state with filling factor $ν=5/2$ are expected to obey non-Abelian statistics. We demonstrate that their statistics can be probed by transport measurements in an electronic Mach-Zehnder interferometer. The tunneling current through the interferometer exhibits a characteristic dependence on the magnetic

  93. Chao Li, Tristan L. Smith, Asantha Cooray

    The B-mode polarization lensing signal is a useful probe of the neutrino mass and to a lesser extent the dark energy equation of state as the signal depends on the integrated mass power spectrum between us and the last scattering surface. This lensing B-mode signal, however, is non-Gaussian and the resulting non-Gaussian covariance to the power spectrum cann

  94. Justin R. David, Dileep P. Jatkar, Ashoke Sen

    We compute the spectrum of quarter BPS dyons in freely acting Z_2 and Z_3 orbifolds of type II string theory compactified on a six dimensional torus. For large charges the result for statistical entropy computed from the degeneracy formula agrees with the corresponding black hole entropy to first non-leading order after taking into account corrections due to

  95. Kengo Matsumoto

    We first observe that the relations of the canonical generating isometries of the Cuntz algebra ${\cal O}_N$ are naturally related to the $N$-colored Catalan numbers. For a directed graph $G$, we generalize the Catalan numbers by using the canonical generating partial isometries of the Cuntz-Krieger algebra ${\cal O}_{A^G}$ for the transition matrix $A^G$ of

  96. J. P. Ma, Q. Wang

    With a consistent definition of transverse-momentum dependent (TMD) light-cone wave function, we show that the amplitude for the process $γ^* π^0 \toγ$ can be factorized when the virtuality of the initial photon is large. In contrast to the collinear factorization in which the amplitude is factorized as a convolution of the standard light-cone wave function

  97. Charles Santori, Philippe Tamarat, Philipp Neumann, Jorg Wrachtrup

    Coherent population trapping is demonstrated in single nitrogen-vacancy centers in diamond under optical excitation. For sufficient excitation power, the fluorescence intensity drops almost to the background level when the laser modulation frequency matches the 2.88 GHz splitting of the ground states. The results are well described theoretically by a four-le

  98. Everett W. Howe, Enric Nart, Christophe Ritzenthaler

    We give a complete answer to the question of which polynomials occur as the characteristic polynomials of Frobenius for genus-2 curves over finite fields.

  99. Ben Rudiak-Gould

    Since Deutsch (1985), quantum computers have been modeled exclusively in the language of state vectors and the Schroedinger equation. We present a complementary view of quantum circuits inspired by the path integral formalism of quantum mechanics, and examine its application to some simple textbook problems.

  100. Jürgen Kästel, Michael Fleischhauer

    We discuss the recent proposal by Thommen and Mandel (Phys. Rev. Lett. {\bf 96}, 053601 (2006)) for electromagnetically induced negative refraction. Although the main conclusion of the paper -- the possibility to achieve negative refraction in an experimentally accessible atomic scheme -- remains valid, we show that the weak-excitation approximation used is