Research archive

arXiv papers from October 2002

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

  1. E. Brion, G. Harel, N. Kebaili, V. M. Akulin

    We show that multidimensional Zeno effect combined with non-holonomic control allows to efficiently protect quantum systems from decoherence by a method similar to classical coding. Contrary to the conventional approach, our method is applicable to arbitrary error-inducing Hamiltonians and general quantum systems. We also propose algorithms of finding encodi

  2. J. C. Yoon

    Quantum field theory has been established on symmetries, but their fundamentality could be limited as practical calculations of physical observations are not based on interacting Lagrangian. The requirement of Lorentz invariance on vacuum expectation values is contradicted by parity violation with massive fermions and Lorentz violation of the approximation i

  3. Byung-Jay Kahng

    In this paper, as a generalization of Kirillov's orbit theory, we explore the relationship between the dressing orbits and irreducible *-representations of the Hopf C*-algebras (A,\Delta) and (\tilde{A}, \tilde{\Delta}) we constructed earlier. We discuss the one-to-one correspondence between them, including their topological aspects. On each dressing orbit (

  4. Byung-Jay Kahng

    In the general theory of locally compact quantum groups, the notion of Haar measure (Haar weight) plays the most significant role. The aim of this paper is to carry out a careful analysis regarding Haar weight, in relation to general theory, for the specific non-compact quantum group (A,\Delta) constructed earlier by the author. In this way, one can show tha

  5. Nicolas Yunes, Matt Visser

    We present a self-contained formalism for analyzing scale invariant differential equations. We first cast the scale invariant model into its equidimensional and autonomous forms, find its fixed points, and then obtain power-law background solutions. After linearizing about these fixed points, we find a second linearized solution, which provides a distinct co

  6. B Talin, E Dufour, A Calisti, M A Gigosos

    The ion-electron coupling properties for a ion impurity in an electron gas and for a two component plasma are carried out on the basis of a regularized electron-ion potential removing the short-range Coulomb divergence. This work is largely motivated by the study of radiator dipole relaxation in plasmas which makes a real link between models and experiments.

  7. Stephen S. Bullock, Igor L. Markov

    Quantum circuits currently constitute a dominant model for quantum computation. Our work addresses the problem of constructing quantum circuits to implement an arbitrary given quantum computation, in the special case of two qubits. We pursue circuits without ancilla qubits and as small a number of elementary quantum gates as possible. Our lower bound for wor

  8. Joshua N. Cooper

    Chung and Graham define quasirandom subsets of $\mathbb{Z}_n$ to be those with any one of a large collection of equivalent random-like properties. We weaken their definition and call a subset of $\mathbb{Z}_n$ $\epsilon$-balanced if its discrepancy on each interval is bounded by $\epsilon n$. A quasirandom permutation, then, is one which maps each interval t

  9. BNL Neutrino Working Group, M. Diwan

    The possibility of making a low cost, very intense (1MW) high energy proton source at the Brookhaven Alternating Gradient Synchrotron (BNL-AGS) along with the forthcoming new large underground detectors (approaching 1 MT in mass) at the National Underground Science and Engineering Laboratory (NUSEL) in Homestake, South Dakota or at the Waste Isolation Pilot

  10. Y. Jack Ng, H. van Dam

    We give a geometrical derivation of the Dirac equation by considering a spin-1/2 particle travelling with the speed of light in a cubic spacetime lattice. The mass of the particle acts to flip the multi-component wavefunction at the lattice sites. Starting with a difference equation for the case of one spatial and one time dimensions, we generalize the appro

  11. Gordon P. Ramsey

    Many of the present and planned polarization experiments are focusing on determination of the polarized glue. There is a comparable set of spin experiments which can help to extract information on the separate flavor-dependent polarized distributions. This talk will discuss possible sets of experiments, some of which are planned at BNL, CERN, DESY and JHF, w

  12. Morrel H. Cohen

    We propose a scheme for extending the model Hamiltonian method developed originally for studying the equilibrium properties of complex perovskite systems to include Langevin dynamics. The extension is based on Zwanzig's treatment of nonlinear generalized Langevin's equations. The parameters entering the equations of motion are to be determined by mapping fro

  13. V. A. Yurovsky, A. Ben-Reuven

    The loss of ultracold trapped atoms in the vicinity of a Feshbach resonance is treated as a two-stage reaction, using the Breit-Wigner theory. The first stage is the formation of a resonant diatomic molecule, and the second one is its deactivation by inelastic collisions with other atoms. This model is applied to the analysis of recent experiments on $^{87}$

  14. O. Leitner, X. -H. Guo, A. W. Thomas

    Direct CP violation in the hadronic decays $\Bar{B}^{0} \to \pi^{+}\pi^{-} \pi^{0}$ is investigated near the peak of the $\rho^{0}$ taking into account the effect of $\rho - \omega$ mixing. Branching ratios for processes $B^{\pm,0} \to \rho^{\pm,0}\pi^{\pm,0}$ and $B^{-} \to \omega \pi^{-}$ are calculated as well. We find that the CP violating asymmetry is s

  15. Victor Pervushin

    Astrophysical data reformulated in the units of the relative Paris meter and running Planck mass are used for restoration of a conformal version of the unified theory where the absolute Planck mass belongs to ordinary initial data (like the absolute Ptolemaeus position of the earth belongs to the initial data of Newton's mechanics). In the conformal unified

  16. Sonja Daffer, Krzysztof Wodkiewicz, John K. McIver

    We examine stochastic maps in the context of quantum optics. Making use of the master equation, the damping basis, and the Bloch picture we calculate a non-unital, completely positive, trace-preserving map with unequal damping eigenvalues. This results in what we call the squeezed vacuum channel. A geometrical picture of the effect of stochastic noise on the

  17. P. Fachini

    Preliminary results on $\rho(770)^0 \to \pi^{+}\pi^{-}$, K$^{*}(892)^{0} \to \pi$K and $f_{0}(980) \to \pi^{+}\pi^{-}$ production using the mixed-event technique are presented. The measurements are performed at mid-rapidity by the STAR detector in $\sqrt{s_{NN}}$= 200 GeV Au-Au and pp interactions at RHIC. The results are compared to different measurements a

  18. Thomas B. Bahder, Chris Fazi

    When a high voltage (~30 kV) is applied to a capacitor whose electrodes have different physical dimensions, the capacitor experiences a net force toward the smaller electrode (Biefeld-Brown effect). We have verified this effect by building four capacitors of different shapes. The effect may have applications to vehicle propulsion and dielectric pumps. We rev

  19. J. J. Palacios, A. J. Perez-Jimenez, E. Louis, E. SanFabian

    We present first-principles calculations of phase coherent electron transport in a carbon nanotube (CNT) with realistic contacts. We focus on the zero-bias response of open metallic CNT's considering two archetypal contact geometries (end and side) and three commonly used metals as electrodes (Al, Au, and Ti). Our ab-initio electrical transport calculations

  20. Gary Shiu

    We discuss the cosmological implications of some recent advances in understanding the dynamics of tachyon condensation in string theory.

  21. Keith R. Dienes, Emilian Dudas, Tony Gherghetta

    Within the context of traditional logarithmic grand unification at M_GUT = 10^(16) GeV, we show that it is nevertheless possible to observe certain GUT states such as X and Y gauge bosons at lower scales, perhaps even in the TeV range. We refer to such states as ``GUT precursors.'' Such states offer an interesting alternative possibility for new physics at t

  22. Wayne Hu

    The tremendous experimental progress in cosmic microwave background (CMB) temperature and polarization anisotropy studies over the last few years has helped establish a standard paradigm for cosmology at intermediate epochs and has simultaneously raised questions regarding the physical processes at the two opposite ends of time. What is the physics behind th

  23. James Dufty, Ilya Pogorelov, Bernard Talin, Annette Calisti

    Electric field dynamics at a positive ion imbedded in an electron gas is considered using a semiclassical description. The dependence of the field autocorrelation function on charge number is studied for strong ion-electron coupling via MD simulation. The qualitative features for larger charge numbers are a decreasing correlation time followed by an increasi

  24. Sabine Hossenfelder, Dominik J. Schwarz, Walter Greiner

    We compute the production of particles from the gravitational field of an expanding mass shell. Contrary to the situation of Hawking radiation and the production of cosmological perturbations during cosmological inflation, the example of an expanding mass shell has no horizon and no singularity. We apply the method of `ray-tracing', first introduced by Hawki

  25. Shufang Su

    We briefly review the single heavy Higgs production at high energy e+e- linear collider, \gamma\gamma collider and e-\gamma collider. We present the recent results for e+e- --> W^{\pm}H^{\mp} in the Minimal Supersymmetric Standard Model and preliminary results for e+e- --> \nu \bar\nu A^0.

  26. Henriette Elvang, Gary T. Horowitz

    We explore the physical consequences of a recently discovered class of exact solutions to five dimensional Kaluza-Klein theory. We find a number of surprising features including: (1) In the presence of a Kaluza-Klein bubble, there are arbitrarily large black holes with topology S^3. (2) In the presence of a black hole or a black string, there are expanding b

  27. George Marinescu, Tien-Cuong Dinh

    We show that the pseudoconcave holes of some naturally arising class of manifolds, called hyperconcave ends, can be filled in, including the case of complex dimension 2 . As a consequence we obtain a stronger version of the compactification theorem of Siu-Yau and extend Nadel's theorems to dimension 2.

  28. S. P. Gavrilov, D. M. Gitman, A. A. Smirnov

    We consider the Dirac equation in the magnetic-solenoid field (the field of a solenoid and a collinear uniform magnetic field). For the case of Aharonov-Bohm solenoid, we construct self-adjoint extensions of the Dirac Hamiltonian using von Neumann's theory of deficiency indices. We find self-adjoint extensions of the Dirac Hamiltonian in both above dimension

  29. A. Pich

    Precise measurements of the lepton properties provide stringent tests of the Standard Model structure and accurate determinations of its parameters. We overview the present status of a few selected topics: lepton universality, QCD tests and the determination of alpha_s and m_s from hadronic tau decays, the anomalous lepton magnetic moments and neutrino oscil

  30. Paul Benioff

    Some aspects of the physical nature of language are discussed. In particular, physical models of language must exist that are efficiently implementable. The existence requirement is essential because without physical models no communication or thinking would be possible. Efficient implementability for creating and reading language expressions is discussed an

  31. J. Wirstam, J. T. Lenaghan, K. Splittorff

    We use a Landau theory and the epsilon expansion to study the superfluid phase transition of two-color QCD at nonzero temperature, T, and baryonic chemical potential, mu. At low T, and for N_f flavors of massless quarks, the global SU(N_f) \times SU(N_f) \times U(1) symmetry is spontaneously broken by a diquark condensate down to Sp(N_f) \times Sp(N_f) for a

  32. D. Monet, S. Levine, B. Canzian, H. Ables

    USNO-B is an all-sky catalog that presents positions, proper motions, magnitudes in various optical passbands, and star/galaxy estimators for 1,042,618,261 objects derived from 3,643,201,733 separate observations. The data were obtained from scans of 7,435 Schmidt plates taken for the various sky surveys during the last 50 years. USNO-B1.0 is believed to pro

  33. D. Brecher, J. P. Gregory, P. M. Saffin

    The presence of fields with negative mass-squared typically leads to some form of instability in standard field theories. The observation that, at least in the light-cone gauge, strings propagating in plane wave spacetimes can have worldsheet scalars with such tachyon-like masses suggests that the supergravity background may itself be unstable. To address th

  34. Risto Raitio

    The model is not satisfactory.

  35. D. Bazeia, R. Menezes, J. R. Nascimento, R. F. Ribeiro

    We introduce a class of higher-order derivative models in (2,1) space-time dimensions. The models are described by a vector field, and contain a Proca-like mass term which prevents gauge invariance. We use the gauge embedding procedure to generate another class of higher-order derivative models, gauge-invariant and dual to the former class. We show that the

  36. Maxim Mostovoy, Nikolai Prokof'ev, Daniel Khomskii, Jasper Knoester

    We show that one-dimensional topological objects (kinks) are natural degrees of freedom for an antiferromagnetic Ising model on a triangular lattice. Its ground states and the coexistence of spin ordering with an extensive zero-temperature entropy can be easily understood in terms of kinks forming a hard-sphere liquid. Using this picture we explain effects o

  37. H. Baer, M. A. Diaz, M. A. Rivera, D. A. Ross

    We use the quantum corrected chargino production cross section, including information on the beam polarization and chargino helicities, to estimate the precision achievable at a 1 TeV, 500 ${\mathrm fb}^{-1}$ Linear Collider on the determination of fundamental supersymmetric parameters from measurements of light chargino mass and production cross sections. W

  38. Giancarlo Ghirlanda, Annalisa Celotti, Gabriele Ghisellini

    We consider the evidence for very hard low energy spectra during the prompt phase of Gamma-Ray Bursts (GRB). In particular we examine the spectral evolution of GRB 980306 together with the detailed analysis of some other bursts already presented in the literature (GRB 911118, GRB 910807, GRB 910927 and GRB 970111), and check for the significance of their har

  39. V. Bozza

    Spherically symmetric black holes produce, by strong field lensing, two infinite series of relativistic images, formed by light rays winding around the black hole at distances comparable to the gravitational radius. In this paper, we address the relevance of the black hole spin for the strong field lensing phenomenology, focusing on trajectories close to the

  40. A. M. Teixeira, G. C. Branco, M. E. Gomez, S. Khalil

    We analyse the CP problem in the context of a supersymmetric extension of the standard model with universal strength of Yukawa couplings. In these models we find a small amount of CP violation from the usual CKM mechanism and therefore a significant contribution from supersymmetry is required. The electric dipole moments impose severe constraints on the para

  41. Francesco De Martini, Andrea Mazzei, Marco Ricci, Giacomo Mauro D'Ariano

    We present the first full experimental quantum tomographic characterization of a single-qubit device achieved with a single entangled input state. The entangled input state plays the role of all possible input states in quantum parallel on the tested device. The method can be trivially extended to any n-qubits device by just replicating the whole experimenta

  42. Jing Jiang, Tianjun Li, Wei Liao

    We propose low energy 6-dimensional N=2 supersymmetric SU(6) models on $M^4\times T^2/(Z_2)^3$ and $M^4\times T^2/(Z_2)^4$, where the orbifold $SU(3)_C\times SU(3)$ model can be embedded on the boundary 4-brane. For the zero modes, the 6-dimensional N=2 supersymmetry and the SU(6) gauge symmetry are broken down to the 4-dimensional N=1 supersymmetry and the

  43. Ting-Wai Chiu, Tung-Han Hsieh, Chao-Hsi Huang, Tsung-Ren Huang

    We outline the essential features of a Linux PC cluster which is now being developed at National Taiwan University, and discuss how to optimize its hardware and software for lattice QCD with overlap Dirac quarks. At present, the cluster constitutes of 30 nodes, with each node consisting of one Pentium 4 processor (1.6/2.0 GHz), one Gbyte of PC800 RDRAM, one

  44. S. Typel, T. v. Chossy, H. H. Wolter

    The quantum hadrodynamics (QHD) model with minimal nucleon-meson couplings is generalized by introducing couplings of mesons to derivatives of the nucleon field in the Lagrangian density. This approach allows an effective description of a state-dependent in-medium interaction in the mean-field approximation. Various parametrizations for the generalized coupl

  45. V. B. Bezerra, G. L. Klimchitskaya, V. M. Mostepanenko

    The energy of fluctuating electromagnetic field is investigated for the thermal Casimir force acting between parallel plates made of real metal. It is proved that for nondissipative media with temperature independent dielectric permittivity the energy at nonzero temperature comprises of the (renormalized) energies of the zero-point and thermal photons. In th

  46. Raphael Bousso

    From the covariant bound on the entropy of partial light-sheets, we derive a version of Bekenstein's bound: S/M \leq pi x/hbar, where S, M, and x are the entropy, total mass, and width of any isolated, weakly gravitating system. Because x can be measured along any spatial direction, the bound becomes unexpectedly tight in thin systems. Our result completes t

  47. Rubina Kotak, Marten H. van Kerkwijk, J. C. Clemens, Detlev Koester

    We report on our findings of the bright, pulsating, helium atmosphere white dwarf GD 358, based on time-resolved optical spectrophotometry. We identify 5 real pulsation modes and at least 6 combination modes at frequencies consistent with those found in previous observations. The measured Doppler shifts from our spectra show variations with amplitudes of up

  48. C. Pernechele, S. Berta, A. Marconi, C. Bonoli

    We report on a spectro-polarimetric analysis of four southern Ultra-Luminous Infrared Galaxies (ULIRGs), aimed at constraining the presence of hidden broad AGN lines. For IRAS 19254--7245 ({\sl The Superantennae}) we find evidence for a significant level of polarized light in the H$\alpha$ line with FWHM$>$2300 km/s. Some degree of polarization is also detec

  49. Jeffrey F. Brock, Kenneth W. Bromberg

    We give an expository account of our proof that each cusp-free hyperbolic 3-manifold M with finitely generated fundamental group and incompressible ends is an algebraic limit of geometrically finite hyperbolic 3-manifolds.

  50. Alessia Moretti, Enrico V. Held, Luca Rizzi, Vincenzo Testa

    We present preliminary results of a wide field study of the globular cluster system of NGC4594, the Sombrero galaxy. The galaxy was observed in B, V, and R using the Wide Field Imager on the ESO 2.2m telescope. Using color and shape criteria to select a sample of highly probable globular cluster candidates, we measured the radial density profile of clusters

  51. William G. McCallum, Pavlos Tzermias

    We extend the results of the first author on nontrivial elements in the Shafarevich-Tate group of the jacobian of a quotient of a Fermat curve of prime degree, and use the methods of the second author to derive a result bounding the quadratic points on the Fermat curve of degree 19.

  52. Daniel de Florian

    We calculate the next-to-leading order QCD corrections to the spin-dependent cross section for single-inclusive hadron production in hadronic collisions. This process will be soon studied experimentally at RHIC, providing a tool to unveil the polarized gluon distribution $\Delta g$. We observe a considerably improvement in the perturbative stability for both

  53. Marc Potters, Jean-Philippe Bouchaud

    We investigate present some new statistical properties of order books. We analyse data from the Nasdaq and investigate (a) the statistics of incoming limit order prices, (b) the shape of the average order book, and (c) the typical life time of a limit order as a function of the distance from the best price. We also determine the `price impact' function using

  54. Matt Mackie, Andrew Carmichael, Marijan Kostrun, Rory J. Perkins

    We examine collective magnetoassociation of a Bose-Einstein condensate (BEC), focusing on rapid adiabatic passage from atoms to molecules induced by a sweep of the magnetic field across a wide (>~ 10 G) Feshbach resonance in 85Rb. This problem raises an interest because strong magnetoassociation is expected to favor the creation of molecular-dissociated atom

  55. Enrico V. Held, Alessia Moretti, Luciana Federici, Carla Cacciari

    We have obtained intermediate-resolution VLT spectroscopy of 75 globular cluster candidates around the Sa galaxy M104 (NGC4594). Fifty-seven candidates out to ~ 40 kpc in the halo of the galaxy were confirmed to be bona-fide globular clusters, 27 of which are new. A first analysis of the velocities provides only marginal evidence for rotation of the cluster

  56. Merritt S. Cook, H. Rudolf Fiebig

    We study mass spectra of a meson-meson system involving two light and two heavy quarks on an anisotropic lattice. The heavy quarks are treated in the static approximation. The dependence of the spectrum on the relative distance of the heavy quarks is extracted from the lattice simulation using the maximum entropy method (MEM). A correlation matrix of meson-m

  57. Olga R. Beaver, Thomas Garrity

    A one-to-one continuous function from a triangle to itself is defined that has both interesting number theoretic and analytic properties. This function is shown to be a natural generalization of the classical Minkowski ?(x) function. It is shown there exists a natural class of pairs of cubic irrational numbers in the same cubic number field that are mapped t

  58. H. Baer, C. Balazs, A. Belyaev, J. Mizukoshi

    Recently, refinements have been made on both the theoretical and experimental determinations of the i.) mass of the lightest Higgs scalar, ii.) relic density of cold dark matter in the universe, iii.) branching fraction for radiative B decay BF(b \to s \gamma), iv.) muon anomalous magnetic moment, and v.) flavor violating decay B_s \to \mu^+\mu^-. In this wo

  59. Sergio R. Fenley

    We analyse the existence question for essential laminations in 3-manifolds. The purpose is to prove that there are infinitely many closed hyperbolic 3-manifolds which do not admit essential laminations. This answers in the negative a question posed by Gabai and Oertel. The proof is obtained by analysing certain group actions on trees and showing that certain

  60. Remi Carles

    We study the Cauchy problem for Schrodinger equations with repulsive quadratic potential and power-like nonlinearity. The local problem is well-posed in the same space as that used when a confining harmonic potential is involved. For a defocusing nonlinearity, it is globally well-posed, and a scattering theory is available, with no long range effect for any

  61. O. Ujsaghy, A. Zawadowski

    Two-level systems (TLS) interacting with conduction electrons are possibly described by the two-channel Kondo Hamiltonian. In this case the channel degeneracy is due to the real spin of the electrons. The possibility of breaking that degeneracy has interest on his own. In fact, we show that the interaction of the conduction electrons with a spin-orbit scatte

  62. M. Kotulla, J. Ahrens, J. R. M. Annand, R. Beck

    The reaction $\gamma p \to \pi^\circ \gamma^\prime p$ has been measured with the TAPS calorimeter at the Mainz Microtron accelerator facility MAMI for energies between $\sqrt{s}$ = 1221--1331 MeV. Cross sections differential in angle and energy have been determined for all particles in the final state in three bins of the excitation energy. This reaction cha

  63. E. Josselin, R. Bachiller

    We report high-sensitivity millimetre observations of several molecular species (13CO, HCN, HNC, CN, HCO+ and N2H+) in a sample of compact planetary nebulae. Some species such as HCO+ and CN are particularly abundant compared to envelopes around AGB stars or even interstellar clouds. We have estimated the following average values for the column densities rat

  64. Guy Katriel

    We prove that, for generic systems of polynomial differential equations, the dependence of the solution on the initial conditions is not differentially algebraic. This answers, in the negative, a question posed by L.A. Rubel.

  65. A. H. Hoang

    A generalization of Wilson's local OPE for the short-distance expansion of Euclidean current correlators, called delocalized operator expansion (DOE), which has been proposed recently, is discussed. The DOE has better convergence properties than the OPE and can account for non-local non-perturbative QCD effects.

  66. Steffen Krusch

    The Skyrme model is a classical field theory which models the strong interaction between atomic nuclei. It has to be quantized in order to compare it to nuclear physics. When the Skyrme model is semi-classically quantized it is important to take the Finkelstein-Rubinstein constraints into account. The aim of this paper is to show how to calculate these FR co

  67. Donald Marolf, Leopoldo A. Pando Zayas

    We describe various aspects of plane wave backgrounds. In particular, we make explicit a simple criterion for singularity by establishing a relation between Brinkmann metric entries and diffeomorphism-invariant curvature information. We also address the stability of plane wave backgrounds by analyzing the fluctuations of generic scalar modes. We focus our at

  68. I. M. Suslov

    The Gell-Mann - Low function \beta(g) in QCD (g=g0^2/16\pi^2 where g0 is the coupling constant in the Lagrangian) is shown to behave in the strong-coupling region as \beta_\infty g^\alpha with \alpha\approx -13, \beta_\infty\sim 10^5.

  69. G. Bertin, M. Trenti

    We examine the thermodynamical properties of a family of partially relaxed, anisotropic stellar systems, derived earlier from the Boltzmann entropy under the assumption that a third quantity Q is conserved in addition to the total energy and the total number of stars. We now show that the family of models conforms to the paradigm of the gravothermal catastro

  70. J. S. Kaastra, R. Lieu, T. Tamura, F. B. S. Paerels

    We investigate a sample of 14 clusters of galaxies observed with XMM-Newton in a search for soft X-ray excess emission. In five of these clusters a significant soft excess is evident. This soft X-ray excess is compared with the thermal emission from both the hot intracluster gas and any cooling (flow) gas that may be present. A warm (kT=0.2 keV), extended (s

  71. Istvan Zoltan Kiss, J. H. Merkin, S. K. Scott, P. L. Simon

    The structure of flame filaments resulting from chaotic mixing within a combustion reaction is considered. The transverse profile of the filaments is investigated numerically and analytically based on a one-dimensional model that represents the effect of stirring as a convergent flow. The dependence of the steady solutions on the Damkohler number and Lewis n

  72. Daniele Dominici

    A brief overview of the production at future colliders of two new triplets of spin one resonances from a strong electroweak breaking is presented.

  73. R. J. Wilman, H. J. A. Rottgering, R. A. Overzier, M. J. Jarvis

    We measure the angular clustering of ~2000 radio sources in The Bootes Deep Field, covering 5.3 deg^2 down to S(1.4 GHz)=0.2 mJy. With reference to work by Blake & Wall, we show that the size distribution of multi-component radio galaxies dominates the overall clustering signal, and that its amplitude extrapolates smoothly from their measurements above 5 mJy

  74. T. Vogt, J. A. Hriljac, N. C. Hyatt, P. Woodward

    Synchrotron X-ray powder diffraction experiments reveal that the transition from a magnetic intermediate spin (IS) state to a nonmagnetic low-spin (LS) ground state in LaCoO3 normally observed when cooling, manifests itself under pressure by an anomalously low bulk compressibility of 150(2) GPa and an initially very large bond compressibility of 4.8e-3 GPa-1

  75. Ken Ebisawa, R. Fujimoto, Y. Ueda

    We are systematically analyzing ASCA GIS data taken during the satellite attitude maneuver operation. Our motivation is to search for serendipitous hard X-ray sources and make the ASCA Slew Survey catalog. During its operational life from 1993 February to 2000 July, ASCA carried out more than 2,500 maneuver operations, and total exposure time during the mane

  76. Wladyslaw Marcinek

    An algebraic model for the relation between a certain classical particle system and the quantum environment is proposed. The quantum environment is described by the category of possible quantum states. The initial particle system is represented by an associative algebra in the category of states. The key new observation is that particle interactions with the

  77. Ken Ebisawa, V. Beckmann, T. J. -L. Courvoisier, P. Dubath

    We have carried out a deep X-ray observation on a typical Galactic plane region with the Chandra ACIS-I instrument with unprecedented sensitivity and spatial resolution, and detected 274 unidentified X-ray point sources in the \~500 arcmin2 region. In order to identify these new X-ray sources, we have carried out a near infrared follow-up observation using E

  78. Ariel Kaplan, Nir Friedman, Mikkel Andersen, Nir Davidson

    We present numerical and experimental results for the development of islands of stability in atom-optics billiards with soft walls. As the walls are soften, stable regions appear near singular periodic trajectories in converging (focusing) and dispersing billiards, and are surrounded by areas of "stickiness" in phase-space. The size of these islands depends

  79. K. Langanke, J. Terasaki, F. Nowacki, D. J. Dean

    We calculate the B(E2) strength in 68Ni and other nickel isotopes using several theoretical approaches. We find that in 68Ni the gamma transition to the first 2+ state exhausts only a fraction of the total B(E2) strength, which is mainly collected in excited states around 5 MeV. This effect is sensitive to the energy splitting between the fp shell and the g_

  80. F. Bouquet, Y. Wang, I. Sheikin, P. Toulemonde

    The two-gap structure in the superconducting state of MgB_2 gives rise to unusual thermodynamic properties which depart markedly from the isotropic single-band BCS model, both in their temperature- and field dependence. We report and discuss measurements of the specific heat up to 16 T on ceramic, and up to 14 T on single crystal samples, which demonstrate t

  81. H. Nikolic

    Since any fermionic operator \psi can be written as \psi=q+ip, where q and p are hermitian operators, we use the eigenvalues of q and p to construct a functional formalism for calculating matrix elements that involve fermionic fields. The formalism is similar to that for bosonic fields and does not involve Grassmann numbers. This makes possible to perform nu

  82. K. Ebisawa, S. Yamauchi, A. Bamba, M. Ueno

    We review highlights of the results obtained from recent Galactic X-ray survey observations, in particular ASCA Galactic center and plane survey and our Chandra deep survey on the (l,b)=(28.5,0) region. Strong hard X-ray diffuse components are observed from Galactic ridge, center and bulge, and they have both thermal and non-thermal spectral components. Doze

  83. J. K. Dewhurst, S. Sharma, C. Ambrosch-Draxl, B. Johansson

    The lattice dynamical properties of Li$_x$BC are calculated for several values of $x$ using density functional perturbation theory. We find that the electron-phonon coupling parameter $\lambda$ increases monotonically with decreasing $x$ to a maximum value of 1.4 for $x=0.125$ owing to the increasing radius of multiply-nested Fermi surface cylinders. The B-C

  84. Kei Tokita, Ayumu Yasutomi

    We propose a minimal model of the dynamics of diversity -- replicator equations with extinction, invasion and mutation. We numerically study the behavior of this simple model and show that it displays completely different behavior from the conventional replicator equation and the generalized Lotka-Volterra equation. We reach several significant conclusions a

  85. A K Pandey, K Upadhyay, Y Nakada, K Ogura

    In this paper we present a detailed study of the intra-cluster reddening material in the young open clusters located around $l \sim 130^o$ using colour-excess diagrams and two-colour diagrams. The study supports the universality of the extinction curves for $\lambda \geq \lambda_J$, whereas for shorter wavelengths the curve depends upon the value of the $R_{

  86. D. K. Park, S. Tamaryan, H. J. W. Müller-Kirsten

    The spherical D2-brane solution is obtained without RR external background. The solution is shown to preserve $(1/4)$ supersymmetries. The configurations obtained depend on the integration constant $R_0$. For $R_0 \neq 0$ the shape of the solution is a deformed sphere. When, however, $R_0 = 0$, the D2-brane system seems to exhibit a brane-anti-brane configur

  87. HERMES Collaboration, A. Airapetian

    Cross section ratios for deep-inelastic scattering from $^3$He, $^{14}$N and $^{84}$Kr with respect to $^2$H have been measured by the HERMES collaboration at DESY using a 27.5 GeV positron beam. The data cover a range in the Bjorken scaling variable $x$ between 0.010 and 0.65, the negative squared four-momentum transfer $Q^2$ varies from 0.5 to 15 GeV$^2$,

  88. HERMES Collaboration, A. Airapetian

    This erratum revokes the main conclusion of a Letter that reported measurements of cross sections for deep-inelastic scattering (DIS) of leptons on $^3$He and $^{14}$N targets, expressed as ratios of $\sigma_A / \sigma_D$ to the cross section on the deuterium target.

  89. S. A. Merkulov

    It is shown that every algebra over the chain operad of the little disks operad gives naturally rise to a Hertling-Manin's F-manifold, that is a smooth manifold equipped with an integrable graded commutative associative product on the tangent sheaf. In particular, moduli spaces of extended deformations of complex/symplectic structures are shown to have a can

  90. Andrea Gabrielli, Michael Joyce, Francesco Sylos Labini

    After reviewing some basic relevant properties of stationary stochastic processes (SSP), we discuss the properties of the so-called Harrison-Zeldovich like spectra of mass density perturbations. These correlations are a fundamental feature of all current standard cosmological models. Examining them in real space we note they imply a "sub-poissonian" normalis

  91. M. Angst, R. Puzniak, A. Wisniewski, J. Roos

    The angular and temperature dependence of the upper critical field Hc2 in MgB2 was determined from torque magnetometry measurements on single crystals. The Hc2 anisotropy gamma_H was found to decrease with increasing temperature, in disagreement with the anisotropic Ginzburg-Landau theory, which predicts that the gamma_H is temperature independent. This beha

  92. Belle collaboration, K. Inami

    We have searched for a CP violation signature arising from an electric dipole moment (d_tau) of the tau lepton in the e+e- -> tau+tau- reaction. Using an optimal observable method and 29.5 fb^{-1} of data collected with the Belle detector at the KEKB collider at sqrt{s} = 10.58 GeV, we find Re(d_tau) = (1.15 +- 1.70) x 10^{-17} ecm and Im(d_tau) = (-0.83 +-

  93. M. d'Astuto, P. K. Mang, P. Giura, A. Shukla

    Inelastic x-ray scattering (IXS) with very high (meV) energy resolution has become a valuable spectroscopic tool, complementing the well established coherent inelastic neutron scattering (INS) technique for phonon dispersion investigations. In the study of crystalline systems IXS is a viable alternative to INS, especially in cases where only small samples ar

  94. M. M. Islam, R. J. Luddy, A. V. Prokudin

    High energy elastic $p p$ scattering at the Large Hadron Collider (LHC) at c.m. energy 14 TeV is predicted using the asymptotic behavior of $\sigma_{tot}(s)$ and $\rho(s)$ known from dispersion relation calculations and the measured elastic $\bar p p$ differential cross section at $\sqrt{s} = 546 {\rm GeV}$. The effective field theory model underlying the ph

  95. T. Schneider

    We show that in anisotropic superconductors, falling at finite temperature into the 3D-XY- and at zero temperature into the 2D-XY-QSI universality class, the isotope effects on transition temperature, specific heat and magnetic penetration depths are not independent, but related by universal relations. The corresponding experimental data for cuprate supercon

  96. A. L. Owczarek, T. Prellberg

    Monte Carlo simulations, using the PERM algorithm, of interacting self-avoiding walks (ISAW) and interacting self-avoiding trails (ISAT) in five dimensions are presented which locate the collapse phase transition in those models. It is argued that the appearance of a transition (at least) as strong as a pseudo-first-order transition occurs in both models. Th

  97. Marc Bocquet, J. T. Chalker

    We consider localisation problems belonging to the chiral symmetry classes, in which sublattice symmetry is responsible for singular behaviour at a band centre. We formulate models which have the relevant symmetries and which are generalisations of the network model introduced previously in the context of the integer quantum Hall plateau transition. We show

  98. Jens Bicker, U. Fritze-v. Alvensleben, K. J. Fricke

    The galaxy population in rich local galaxy clusters shows a ratio of one quarter elliptical galaxies, two quarters S0 galaxies, and one quarter spiral galaxies. Observations of clusters at redshift 0.5 show a perspicuously different ratio, the dominant galaxy type are spiral galaxies with a fraction of two quarters while the number of S0 galaxies decreases t

  99. Yasuaki Hikida

    Liouville field theory on an unoriented surface is investigated, in particular, the one point function on a RP^2 is calculated. The constraint of the one point function is obtained by using the crossing symmetry of the two point function. There are many solutions of the constraint and we can choose one of them by considering the modular bootstrap.

  100. Jean-Claude Hausmann

    For a m-tuple a=(a_1,...,a_m) of positive real numbers, the robot arm of type a in R^d is the map f^a:(S^{d-1})^m -> R^d defined by f^a(z_1,...,z_m) to be the sum of the a_jz_j's. Our aim is to attack the inverse problem via the horizontal liftings for the distribution Delta^a orthogonal to the fibers of f^a. One shows that the connected components by horizo