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February 2002 arXiv papers — page 12

Showing 1,101–1,200 of 2,525 papers

  1. Henk Bearda, Wouter Hartmann, Ken Ebisawa, John Heise

    We present the X-ray spectrum of MR Vel/RXJ0925.7-4758 obtained with the Medium Energy Grating spectrometer of the Chandra X-ray Telescope. The simplest models used by earlier authors, stellar atmospheres in combination with a thermal plasma in collisional ionization equilibrium, cannot explain the spectrum. Neither does a photo-ionized plasma. We identify P

  2. Luigi Spinoglio, Paola Andreani, Matthew A. Malkan

    New far-infrared photometry with ISOPHOT, onboard the Infrared Space Observatory, is presented for 58 galaxies with homogeneous published data for another 32 galaxies all belonging to the 12 micron galaxy sample. In total 29 Seyfert 1's, 35 Seyfert 2's and 12 starburst galaxies, about half of the 12 micron active galaxy sample, plus 14 normal galaxie

  3. Jeremy Allington-Smith, Graham Murray, Robert Content, George Dodsworth

    The Gemini Multiobject Spectrograph (GMOS) installed on the Gemini-North telescope has a facility for integral field spectroscopy over the wavelength range 0.4-1.0um. GMOS is converted to this mode by the remote insertion of an integral field unit (IFU) into the beam in place of the masks used for multiobject spectroscopy. With the IFU deployed, integral fie

  4. D. Galli, F. Palla

    We review and update some aspects of deuterium chemistry in the post-recombination Universe with particular emphasis on the formation and destruction of HD. We examine in detail the available theoretical and experimental data for the leading reactions of deuterium chemistry and we highlight the areas where improvements in the determination of rate coefficien

  5. Javier Trujillo-Bueno

    This article presents an introduction to optical pumping, atomic polarization and the Hanle effect in weakly magnetized stellar atmospheres. Although the physical processes and the theoretical framework described here are of interest for applications in a variety of astrophysical contexts (e.g. scattering polarization in circumstellar envelopes and polarizat

  6. M. Takami, A. Chrysostomou, J. Bailey, T. M. Gledhill

    We present long-slit spectroscopy and spectro-astrometry of HeI 1.083 micron emission in the T Tauri star, DG Tau. We identify three components in the HeI feature: (1) a blueshifted emission component atv -200 km s^-1, (2) a bright emission component at zero-velocity with a FWZI of ~500 km s^-1, and (3) a blueshifted absorption feature at velocities between

  7. Massimo Ramella, Margaret J. Geller, Armando Pisani, Luiz N. da Costa

    We apply a friends-of-friends algorithm to the combined UZC and SSRS2 redshift surveys to construct a catalog of 1168 groups of galaxies; 411 of these groups have 5 or more members within the redshift survey. The group catalog covers 4.69 steradians and all groups exceed a number density contrast threshold of 80. We demonstrate that the groups catalog is hom

  8. Pasquale Mazzotta, Alexey Vikhlinin, Roberto Fusco-Femiano, Maxim Markevich

    A3667, a spectacular merger cluster, was observed by Chandra twice. In this paper we review the main results of the analysis of these observations. In particular we show evidence for the presence in the cluster of a 300 kpc Kelvin-Helmholtz hydrodynamic instability. We discuss the development of such instability and the structure of the intracluster magnetic

  9. R. Barrena, A. Biviano, M. Ramella, E. E. Falco

    We present the results of a new spectroscopic and photometric survey of the hot X-ray cluster 1E0657-56, at z=0.296. We determine the presence of a low velocity dispersion subcluster, which is offset from the main cluster position by 0.7 Mpc and about 600 km/s. We determine the virial masses and total luminosities of the cluster and its subcluster, and solve

  10. F. Palla, D. Galli, A. Marconi, L. Stanghellini

    We present high resolution HST ultraviolet spectroscopy of NGC3242, the only planetary nebula with a measured abundance of 3He. The Space Telescope Imaging Spectrograph (STIS) has been used to observe the CIII multiplet near 1908 A. The presence of 12C and 13C lines at these wavelengths allows a direct estimate of the carbon isotopic ratio in the ionized gas

  11. M. Contini, M. Radovich, P. Rafanelli, G. M. Richter

    Detailed modeling of the different regions of NGC 7130 is presented, accounting for its composite nature of AGN and starburst galaxy. Shock waves, created by stellar winds from hot massive stars and by supernova ejecta, are evident in the continuum and line spectra emitted from the clouds. The AGN starburst connection is discussed on the basis of model resul

  12. Alan R. White

    Infra-red properties of the triangle anomaly and the ``anomaly pole'' are elaborated and applied to the study of high-energy scattering in QCD, when the gauge symmetry is partially broken to SU(2). It is shown that the chiral flavor anomaly provides a wee-gluon component for Goldstone bosons that combines with interactions due to the U(1) anomaly to

  13. M. Gogberashvili

    Embedding of the brane metric into Euclidean (2+4)-space is found. Brane geometry can be visualized as the surface of the hyper-sphere in six dimensions which 'radius' is governed by the cosmological constant. Minkowski space in this picture is lied on the intersection of this surface with the plane formed by the extra space-like and time-like coordi

  14. Uri Keshet, Eli Waxman, Abraham Loeb, Volker Springel

    Structure formation in the intergalactic medium (IGM) produces large-scale, collisionless shock waves, where electrons can accelerate to highly relativistic energies. Such electrons can Compton scatter cosmic microwave background photons up to gamma-ray energies. We study the radiation emitted in this process using a hydrodynamic cosmological simulation of a

  15. William G. McCallum, Romyar T. Sharifi

    Let K be a number field containing the group of n-th roots of unity and S a set of primes of K including all those dividing n and all real archimedean places. We consider the cup product on the first Galois cohomology group of the maximal S-ramified extension of K with coefficients in n-th roots of unity, which yields a pairing on a subgroup of the multiplic

  16. Oleg Kupervasser, Alexsander Vardy

    Bayes Classifiers are widely used currently for recognition, identification and knowledge discovery. The fields of application are, for example, image processing, medicine, chemistry (QSAR). But by mysterious way the Naive Bayes Classifier usually gives a very nice and good presentation of a recognition. It can not be improved considerably by more complex mo

  17. Thomas Klose, Sorin Marculescu

    The bulk quantization method is used for regularizing a conventional four dimensional theory of massless fermions coupled to an external non-Abelian gauge field and for subsequently evaluating the associated Ward identity. As a result one obtains the well-known chiral anomaly.

  18. M. M. Kaufman Bernado, G. E. Romero, I. F. Mirabel

    The recent discovery by Paredes et al. (2000) of a persistent microquasar that is positionally coincident with an unidentified gamma-ray source has open the possibility that other sources in the Third EGRET Catalog could be interpreted as microquasars as well. In this letter we show that some variable unidentified EGRET sources in the galactic plane could be

  19. Sumiyoshi Abe, J. Zak

    Based on the recently introduced averaging procedure in phase space, a new type of entropy is defined on the von Neumann lattice. This quantity can be interpreted as a measure of uncertainty associated with simultaneous measurement of the position and momentum observables in the discrete subset of the phase space. Evaluating for a class of the coherent state

  20. B. Drossel, A. J. McKane

    We review theoretical approaches to the understanding of food webs. After an overview of the available food web data, we discuss three different classes of models. The first class comprise static models, which assign links between species according to some simple rule. The second class are dynamical models, which include the population dynamics of several in

  21. Naoto Kataoka, Kunihiko Kaneko

    As a first step toward realizing a dynamical system that evolves while spontaneously determining its own rule for time evolution, function dynamics (FD) is analyzed. FD consists of a functional equation with a self-referential term, given as a dynamical system of a 1-dimensional map. Through the time evolution of this system, a dynamical graph (a network) em

  22. T A Larsson

    Degenerate modules of the exceptional infinite-dimensional simple Lie superalgebras vle(3|6), ksle(5|10) and mb(3|8) have recently been constructed by Kac and Rudakov, and by Grozman, Leites and Shchepochkina. I rederive their results using a formalism which is contragredient to theirs; instead of finding singular vectors in induced modules, I build reducibl

  23. Long Wang, Wensheng Yu, Lin Zhang

    By using the complete discrimination system for polynomials, we study the number of positive solutions in {\small $C[0,1]$} to the integral equation {\small $ϕ(x)=\int_0^1k(x,y)ϕ^n(y)dy$}, where {\small $k(x,y)=ϕ_1(x)ϕ_1(y)+ϕ_2(x)ϕ_2(y), ϕ_i(x)>0, ϕ_i(y)>0, 0<x,y<1, i=1,2,$} are continuous functions on {\small $[0,1]$}, {\small $n$} is a positive integer. We

  24. Paul Fabel

    We construct an isotopy of a planar compactum that is not the restriction of an isotopy of any planar continuum.

  25. Sergei Buyalo

    Let M be a closed 3-dimensional graph manifold. We prove that h(g)>1 for each geometrization g of M, where h(g) is the topological entropy of geodesic flow of g.

  26. Wadim Zudilin

    We present a new `elementary' proof of the irrationality of $\zeta(3)$ based on some recent `hypergeometric' ideas of Yu.Nesterenko, T.Rivoal, and K.Ball, and on Zeilberger's algorithm of creative telescoping.

  27. Yuriy Drozd, Gert-Martin Greuel, Irina Kashuba

    A description of Cohen-Macaulay modules over cusp surface singularities and over unimodule hypersurface singularities of type T is given. It is proved that among minimally elliptic singularities and their quotients only simple elliptic and cusps are tame, all others are wild (with respect to the classification of Cohen-Macaulay modules).

  28. Yuriy Drozd

    We prove that the description of cubic functors is a wild problem in the sense of the representation theory. On the contrary, we describe several special classes of such functors (2-divisible, weakly alternative, vector spaces and torsion free ones). We also prove that cubic functors can be defined locally and obtain corollaries about their projective dimens

  29. Dan Mangoubi

    In this thesis we consider a way to construct a rich family of compact Riemann Surfaces in a combinatorial way. Given a 3-regualr graph with orientation, we construct a finite-area hyperbolic Riemann surface by gluing triangles according to the combinatorics of the graph. We then compactify this surface by adding finitely many points. We discuss this constru

  30. Long Wang

    This paper discusses the asymptotic periodic behavior of a class of switched discrete event systems, and shows how to evaluate the asymptotic performance of such systems.

  31. Jailton C. Ferreira

    This work presents theorems which state (i) Z is a proper subset for any bijection f between A and Z, where Z is contained in P(A), A is a non-finite set and |Z|=|A|, and (ii) being Z a proper subset of P(A) nothing affirms or denies that |P(A)|>|A|. Russell&#39;s paradox is examined and it is shown that the set of all the ordinary sets does not exist. A mis

  32. C. N. Ferreira

    We show that it is possible to build up a consistent model describing a superconducting cosmic string (SCS) endowed with torsion. A full string solution is obtained by matching the internal and the external solutions. We derive the deficit angle, the geodesics of and the gravitational force on a test-particle moving under the action of this screwed SCS. A co

  33. E. H Saidi

    Considering the complex n-dimension Calabi-Yau homogeneous hyper-surfaces ${\cal H}_{n}$ and using algebraic geometry methods, we develop the crossed product algebra method, introduced by Berenstein et Leigh in hep-th/0105229, and build the non commutative (NC) geometries for orbifolds ${\cal O}={\cal H}_{n}/{\bf Z}_{n+2}^{n}$ with a discrete torsion matrix

  34. Satish D. Joglekar

    Evaluation of variation of a Green&#39;s function in a gauge field theory with a gauge parameter theta involves field transformations that are (close to) singular. Recently, we had demonstrated {hep-th/0106264}some unusual results that follow from this fact for an interpolating gauge interpolating between the Feynman and the Coulomb gauge (formulated by Dous

  35. Robert H. Brandenberger, Brandon Carter, Anne-Christine Davis

    Embedded defects are predicted in a host of particle physics theories, in particular in the standard electroweak theory. They can be stabilized by interactions with the cosmological plasma, but will decay once the plasma falls out of equilibrium, emitting a substantial fraction of non-thermal photons. If the decay happens after a redshift of about $10^6$, th

  36. M. N. Chernodub, K. Ishiguro, T. Suzuki

    We propose to consider lattice monopoles in gluodynamics as continuum monopoles blocked to the lattice. In this approach the lattice is associated with a measuring device consisting of finite-sized detectors of monopoles (lattice cells). Thus a continuum monopole theory defines the dynamics of the lattice monopoles. We apply this idea to the static monopoles

  37. Delia Ionescu

    In this paper, I determine the electrogravitational field produced by a charged mass point according to the Relativistic Theory of Gravitation. The Causality Principle in the Relativistic Theory of Gravitation will play a very important part in finding this field. The analytical form and the domain of definition, i.e the gravitational radius of the obtained

  38. Marc Mars, Thomas Wolf

    We study the Einstein field equations for spacetimes admitting a maximal two-dimensional abelian group of isometries acting orthogonally transitively on spacelike surfaces and, in addition, with at least one conformal Killing vector. The three-dimensional conformal group is restricted to the case when the two-dimensional abelian isometry subalgebra is an ide

  39. Sean A. Hayward

    Traversible wormhole space-times are found as static, spherically symmetric solutions to the Einstein equations with ingoing and outgoing pure ghost radiation, i.e. pure radiation with negative energy density. Switching off the radiation causes the wormhole to collapse to a Schwarzschild black hole.

  40. Delia Ionescu

    The generalization of the concept of homogeneous gravitational field from Classical Mechanics was considered in the framework of Einstein&#39;s General Relativity by Bogorodskii. In this paper, I look for such a generalization in the framework of the Relativistic Theory of Gravitation. There exist a substantial difference between the solutions in these two t

  41. Oskar Vafek, Zlatko Tesanovic

    Presented is the theory of thermal Hall conductivity $κ_{xy}$ in the vortex state of high temperature cuprate superconductors in the clean limit. We show that $\lim_{T \to 0} κ_{xy}/T$ is a {\em staircase} function of 1/B with an envelope that scales as 1/B. The relation to the experiments is discussed.

  42. E. L. Ivchenko, B. Spivak

    We consider chirality related effects in optical, photogalvanic and electron-transport properties of carbon nanotubes. We show that these properties of chiral nanotubes are determined by terms in the electron effective Hamiltonian describing the coupling between the electron wavevector along the tube principal axis and the orbital momentum around the tube ci

  43. Prabhakar P. Singh, P. Jiji Thomas Joseph

    We have studied the electronic structure of 3d transition-metal- MgB_{2} alloys, Mg_{0.97}TM_{0.03}B_{2}, (TM\equiv Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn) using KKR-CPA method in the atomic-sphere approximation. For unpolarized calculations, our results for Mg_{0.97}TM_{0.03}B_{2} alloys are similar to that of 3d impurities in other s and s-p metals. In part

  44. N. Sh. Izmailian, K. B. Oganesyan, Chin-Kun Hu

    Finite-size scaling, finite-size corrections, and boundary effects for critical systems have attracted much attention in recent years. Here we derive exact finite-size corrections for the free energy F and the specific heat C of the critical ferromagnetic Ising model on the M x 2N square lattice with Brascamp-Kunz (BK) boundary conditions [J. Math. Phys. 15,

  45. L. E. Helseth, A. G. Solovyev, R. W. Hansen

    We have investigated the Faraday rotation of in-plane magnetized bismuth - substituted ferrite garnet films grown by liquid phase epitaxy on (100) oriented gadolinium gallium garnet substrates. The Faraday spectra were measured for photon energies between 1.7 - 2.6 eV. To interprete the spectra, we use a model based on two electric dipole transitions, one te

  46. A. S. Wilson, K. A. Arnaud, D. A. Smith, Y. Terashima

    We report Chandra imaging-spectroscopy and RXTE spectroscopy of the nearby, powerful radio galaxy Cygnus A. Various aspects of the results are discussed, including the X-ray properties of the nucleus, the radio hot spots, the cluster of galaxies, the prolate cavity in the ICM inflated by the radio jets and ``bands&#39;&#39; of thermal gas which encircle the

  47. Q. Daniel Wang

    I review our recent Chandra surveys of the center region of the Milky Way and other nearby edge-on galaxies. Our Galactic center survey provides an unprecedented high-resolution, broad-band X-ray panorama of a 0.8x2 square degree swath along the Galactic plane. Our preliminary analysis has led a detection of about 1000 discrete sources. We find that the diff

  48. N. J. Gunther

    Criticism of Gnutella network scalability has rested on the bandwidth attributes of the original interconnection topology: a Cayley tree. Trees, in general, are known to have lower aggregate bandwidth than higher dimensional topologies e.g., hypercubes, meshes and tori. Gnutella was intended to support thousands to millions of peers. Studies of interconnecti

  49. Anthony E. Scoville

    What is the role of the constants of nature in physical theory? I hypothesize that the observable universe, u0, constitutes a Universal Turing Machine (UTM) constrained by algorithmically random logical tape parameters defining its material properties (a physical UTM). The finite non-zero empirical values of Planck&#39;s constant, h, and other constants of n

  50. Q. Wang, K. Redlich, H. Stöcker, W. Greiner

    The non-equilibrium quantum field dynamics is usually described in the closed-time-path formalism. The initial state correlations are introduced into the generating functional by non-local source terms. We propose a functional approach to the Dyson-Schwinger equation, which treats the non-local and local source terms in the same way. In this approach, the ge

  51. Toshiaki Tanaka

    We construct a family of quasi-solvable quantum many-body systems by an algebraic method. The models contain up to two-body interactions and have permutation symmetry. We classify these models under the consideration of invariance property. It turns out that this family includes the rational, hyperbolic (trigonometric) and elliptic Inozemtsev models as the p

  52. Tomaz Zwitter

    Spectrograph aboard the GAIA satellite operates in the near-IR, in the 8490-- 8740 Åwindow accessible also from the ground. The most important parameter yet to be determined is the spectral resolution. Realistic estimates of the zodiacal light background are obtained and a total of $2\times 10^5$ correlation runs are used to study the accuracy of radial velo

  53. XuBo Zou, K. Pahlke, W. Mathis

    We present a scheme to produce an entangled four-photon W-state by using linear optical elements. The symmetrical setup of linear optical elements consists of four beam splitters, four polarization beam splitters and four mirrors. A photon EPR-pair and two single photons are required as the input modes. The projection on the W-state can be made by a four-pho

  54. Keiji Igi, Muneyuki Ishida

    We propose to use rich informations on pi p total cross sections below N= 10 GeV in addition to high-energy data in order to discriminate whether these cross sections increase like log nu or (log nu)^2 at high energies, since it is difficult to discriminate between asymptotic log nu and (log nu)^2 fits from high-energy data alone. A finite-energy sum rule (F

  55. Shin&#39;ichi Nojiri, Sergei D. Odintsov, Sachiko Ogushi

    We consider de Sitter brane-world motivated by dS/CFT correspondence where both bulk and brane are de Sitter spaces. The brane tension is fixed by holographic RG. The 4d effective action for metric perturbations and 4d graviton correlator are explicitly found. The induced values of cosmological and Newton constants are calculated. The short distance behaviou

  56. Sang-Jin Sin

    We discuss the localized tachyon condensation in the non-supersymmetric orbifold theories by taking the cosmological constant as the measure of degrees of freedom (d.o.f). We first show asymptotic density of state is not a proper quantity to count the &#39;localized&#39; d.o.f. We then show that localized d.o.f lead us a c-function given by the lightest tach

  57. J. Xu, J. J. Bock, K. M. Ganga, V. Gorjian

    We present a Monte-Carlo technique to probe the cosmic Infrared background radiation (CIB) with faint source confusion in deep, wide-field 4 micron images. We report a detection of surface brightness fluctuations using an ensemble of 5000 pixels. The brightness fluctuations do not show correlated structure and appear to be dominated by galaxies. We estimate

  58. Sidney A. Coon, Barry R. Holstein

    An anomaly is said to occur when a symmetry that is valid classically becomes broken as a result of quantization. Although most manifestations of this phenomenon are in the context of quantum field theory, there are at least two cases in quantum mechanics--the two dimensional delta function interaction and the 1/r^2 potential. The former has been treated in

  59. Ashfaq Hussain Khosa, M. Suhail Zubairy

    This paper has been withdrawn by the author(s)

  60. J. Patera, R. Twarock

    Unique affine extensions $H^{\aff}_2$, $H^{\aff}_3$ and $H^{\aff}_4$ are determined for the noncrystallographic Coxeter groups $H_2$, $H_3$ and $H_4$. They are used for the construction of new mathematical models for quasicrystal fragments with 10-fold symmetry. The case of $H^{\aff}_2$ corresponding to planar point sets is discussed in detail. In contrast t

  61. Long Wang

    In this paper, we study the frequency response of uncertain systems using Kharitonov stability theory on first order complex polynomial set. For an interval transfer function, we show that the minimal real part of the frequency response at any fixed frequency is attained at some prescribed vertex transfer functions. By further geometric and algebraic analysi

  62. Alexander S. Yessenin-Volpin, Christer Hennix

    This paper gives a counterexample to the impossibility, by Gödel&#39;s second incompleteness theorem, of proving a formula expressing the consistency of arithmetic in a fragment of arithmetic on the assumption that the latter is consistent. This counterexample gives rise to a new type of metamathematical paradox, to be called the Gödel-Wette paradox, which E

  63. Kiyoshi Shiraishi

    Noncommutative gravity in three dimensions with no cosmological constant is reviewed. We find a solution which describes the presence of a torsional source.

  64. M. Carena, S. Heinemeyer, C. E. M. Wagner, G. Weiglein

    The Higgs boson search has shifted from LEP2 to the Tevatron and will subsequently move to the LHC. Due to the different initial states, the Higgs production and decay channels relevant for Higgs boson searches were different at LEP2 to what they are at hadron colliders. We suggest new benchmark scenarios for the MSSM Higgs boson search at hadron colliders t

  65. M. Frank, S. Heinemeyer, W. Hollik, G. Weiglein

    An updated version is presented of the Fortran code FeynHiggs for the evaluation of the neutral CP-even Higgs sector masses and mixing angles. It differs from the previous version by a modification of the renormalization scheme concerning the treatment of subleading terms at the one-loop level; the two-loop corrections, for which the leading contributions of

  66. Zheng Xiaoping, Li Jiarong

    We compare the effective dynamics of soft fields, based on temperature field theory, with the mean field dynamics from non-Abelian kinetic theory. We derive the polarization tensor with the leading logarithmic factor $\log({gT\overμ})$ from the effective Boltzmann-Langevin equation given by Litim and Manuel. The tensor is identical with effective one-loop co

  67. Debajyoti Choudhury, Tim M. P. Tait, C. E. M. Wagner

    The last years have seen a great development in our understanding of particle physics at the weak scale. Precision electroweak observables have played a key role in this process and their values are consistent, within the Standard Model interpretation, with a light Higgs boson with mass lower than about 200 GeV. If new physics were responsible for the mechan

  68. C. Giunti, M. Laveder

    We propose an explanation of the NuTeV anomaly in terms of oscillations of electron neutrinos into sterile neutrinos. We derive an approximate average transition probability P(nu_e->nu_s) = 0.21 +- 0.07, which is compatible with other neutrino data if the mass-squared difference Delta m^2 that drives the oscillations is about 10 - 100 eV^2.

  69. C. Timm, D. Manske, K. H. Bennemann

    In underdoped cuprates fluctuations of the phase of the superconducting order parameter play a role due to the small superfluid density. We consider the effects of phase fluctuations assuming the exchange of spin fluctuations to be the predominant pairing interaction. Spin fluctuations are treated in the fluctuation-exchange approximation, while phase fluctu

  70. T. Geetha Kumary, J. Janaki, Awadhesh Mani, S. Mathi Jaya

    Results of our study on the superconducting and normal state properties of the recently discovered superconductor MgCNi_3, the effect of Fe and Co substitution at the Ni site and the effect of pressure are reported. It is shown that a two band model provides a consistent interpretation of the temperature dependence of the normal state resistance and the Hall

  71. A. I. Leonov, V. S. Volkov

    A nonlinear viscoelastic theory of nematodynamic type is developed for nematic liquid crystalline (LC) semi-flexible polymers. A measure of transient elastic strain due to the change in length of macromolecular strands under stress, and the director of unit length are employed in the theory as hidden variables. In the marked contrast to the common theoretica

  72. A. K. Aringazin, M. I. Mazhitov

    Assuming that the maximal allowed number of identical particles in state is an integer parameter, q, we derive the statistical weight and analyze the associated equation which defines the statistical distribution. The derived distribution covers Fermi-Dirac and Bose-Einstein ones in the particular cases q = 1 and q -> infinity (n_i/q -> 1), respectively. We

  73. J. D. Monnier, P. G. Tuthill, W. C. Danchi

    The eccentric WR+O binary system WR 140 produces dust for a few months at intervals of 7.94 yrs coincident with periastron passage. We present the first resolved images of this dust shell, at binary phases ~0.039 and ~0.055, using aperture masking techniques on the Keck-I telescope to achieve diffraction-limited resolution. Proper motions of approximately 1.

  74. Mats Carlsson, Robert F. Stein

    We investigate the ionization of hydrogen in a dynamic Solar atmosphere. We show that the time scale for ionization/recombination can be estimated from the eigenvalues of a modified rate matrix where the optically thick Lyman transitions that are in detailed balance have been excluded. We find that the time scale for ionization/recombination is dominated by

  75. W. N. Brandt, D. M. Alexander, F. E. Bauer, A. E. Hornschemeier

    Chandra has performed a 1.4 Ms survey centred on the Hubble Deep Field-North (HDF-N), probing the X-ray Universe 55-550 times deeper than was possible with pre-Chandra missions. We describe the detected point and extended X-ray sources and discuss their overall multiwavelength (optical, infrared, submillimeter, and radio) properties. Special attention is pai

  76. Neal Dalal, Christopher S. Kochanek

    We place limits on the linear power spectrum on small scales (k > 50 h/Mpc) using measurements of substructure in gravitational lens galaxies. We find excellent agreement with the simplest LambdaCDM models, and in conjunction with other cosmological probes, place constraints on the neutrino mass m_nu, tilt of the primordial power spectrum n, and mass of the

  77. Henning Heiselberg

    A review of current neutron star masses and radius measurements is given and the resulting constraints on modern equation of states for nuclear matter. Phase transitions in particular to quark matter is discussed and the novel color superconducting mixed phases.

  78. Ariel R. Zhitnitsky

    We discuss a novel cold dark matter candidate which is formed from the ordinary quarks during the QCD phase transition when the axion domain wall undergoes an unchecked collapse due to the tension in the wall. If a large number of quarks is trapped inside the bulk of a closed axion domain wall, the collapse stops due to the internal Fermi pressure. In this c

  79. Stephen T. Holland, I. Soszynski, Michael D. Gladders, L. F. Barrientos

    We present early-time optical photometry and spectroscopy of the optical afterglow of the gamma-ray burst GRB 011211. The spectrum of the optical afterglow contains several narrow metal lines which are consistent with the burst occurring at a redshift of 2.140 +/- 0.001. The optical afterglow decays as a power law with a slope of alpha = 0.83 +/- 0.04 for th

  80. Frederic Leblond, Donald Marolf, Robert C. Myers

    We study solutions of Einstein gravity coupled to a positive cosmological constant and matter, which are asymptotically de Sitter and homogeneous. Regarded as perturbations of de Sitter space, a theorem of Gao and Wald implies that generically these solutions are `tall,' meaning that the perturbed universe lives through enough conformal time for an entire sp

  81. J. M. Grimstrup, H. Grosse, L. Popp, V. Putz

    We analyse the IR-singularities that appear in a noncommutative scalar quantum field theory on $\mathcal{E}_4$. We demonstrate with the help of the quadratic one-loop effective action and an appropriate field redefinition that no IR-singularities exist. No new degrees of freedom are needed to describe the UV/IR-mixing.

  82. G. Annino, M. Cassettari, M. Fittipaldi, M. Martinelli

    A vectorial analysis of magnetic resonance spectrometers, based on traveling wave resonators and including the reference arm and the automatic control of frequency, has been developed. The proposed model, valid also for stationary wave resonators, gives the response function of the spectrometer for any working condition, including scalar detectors with arbit

  83. J. L. Hewett, T. G. Rizzo

    We examine how mixing between the Standard Model Higgs boson, $h$, and the radion present in the Randall-Sundrum model of localized gravity modifies the expected properties of the Higgs boson. In particular, we demonstrate that the total and partial decay widths of the Higgs, as well as the $h\to gg$ branching fraction, can be substantially altered from thei

  84. Stephen M. Barnett, Anthony Chefles, Igor Jex

    We investigate the extent to which we can establish whether or not two quantum systems have been prepared in the same state. We investigate the possibility of universal unambiguous state comparison. We show that it is impossible to conclusively identify two pure unknown states as being identical, and construct the optimal measurement for conclusively identif

  85. V. A. Baulin, A. Halperin

    The Flory chi parameter is typically assumed to depend only on the temperature, T. Experimental results often require the replacement of this chi(T) by chieff, that depends also on the monomer volume fraction, phi, chieff(phi,T). Such chieff(phi,T) can arise from two state-models, proposed for polyetheleneoxide (PEO) and other neutral water-soluble polymers.

  86. A. A. Kirillov, D. Turaev

    We discuss a Modified Field Theory (MOFT) in which the number of fields can vary. It is shown that when the number of fields is conserved MOFT reduces to the standard field theory but interaction constants undergo an additional renormalization and acquire a dependence on spatial scales. In particular, the renormalization of the gravitational constant leads t

  87. Miroslav Jezek

    Discrimination task is treated in the case of only partial prior information from measurements of unknown states. The construction of the optimal discrimination device and estimation of unknown states is performed simultaneously. A communication through a noisy quantum channel is formulated in terms of the proposed discrimination protocol.

  88. M. Ossendrijver, M. Stix, A. Brandenburg, G. Ruediger

    We study the pumping of magnetic flux in three-dimensional compressible magnetoconvection in the context of stellar dynamos. The simulation domain represents a rectangular section from the lower part of a stellar convection zone plus the underlying stably stratified layer, with a total depth of up to five pressure scale heights. Once convection has attained

  89. D. Lacoste, A. W. C. Lau, T. C. Lubensky

    In this paper, we discuss the equilibrium phases and collapse transitions of a lyotropic nematic gel immersed in an isotropic solvent. A nematic gel consists of a cross-linked polymer network with rod-like molecules embedded in it. Upon decreasing the quality of the solvent, we find that a lyotropic nematic gel undergoes a discontinuous volume change accompa

  90. Gautam Bhattacharyya, Srubabati Goswami, Amitava Raychaudhuri

    We study the renormalization of the $llHH$-type Majorana neutrino mass operator in a scenario where there is a compactified extra dimension and the fields involved correspond to only the standard model particles and their Kaluza-Klein excitations. We observe that in a two flavour scenario, where one of the neutrinos is necessarily $ν_τ$, it is indeed possibl

  91. Gebhard Gruebl, Klaus Rheinberger

    We develop a new conception for the quantum mechanical arrival time distribution from the perspective of Bohmian mechanics. A detection probability for detectors sensitive to quite arbitrary spacetime domains is formulated. Basic positivity and monotonicity properties are established. We show that our detection probability improves and generalises earlier pr

  92. Reuven Cohen, Daniel ben-Avraham, Shlomo Havlin

    We study the behavior of scale-free networks, having connectivity distribution P(k) k^-a, close to the percolation threshold. We show that for networks with 3<a<4, known to undergo a transition at a finite threshold of dilution, the critical exponents are different than the expected mean-field values of regular percolation in infinite dimensions. Networks wi

  93. Toshihiko Ota, Joe Sato

    In this letter we explore whether we have a chance to observe a flavor-changing effect in $τ$ appearance experiments ICARUS and OPERA.

  94. Hideshi Baba, Ken Sasaki, Tsuneo Uematsu

    We investigate the twist-3 effects in the polarized virtual photon structure. The structure functions $g_1^γ$ and $g_2^γ$ of polarized photon could be experimentally studied in the future polarized $ep$ or $e^+e^-$ colliders. The leading contributions to $g_1^γ$ are the twist-2 effects, while another structure function $g_2^γ$, which only exists for the virt

  95. H. Yoshioka

    Magnetic properties in a charge ordered state are examined for the extended Hubbard model at half-filling. Magnetic excitations, magnetic susceptibilities and a nuclear spin relaxation rate are calculated with taking account of fluctuations around the mean-field solution. The relevance of the present results to the observation in the 1:1 organic conductors,

  96. Kazuyuki Fujii

    Explicit forms are given of matrix elements of generalized coherent operators based on Lie algebras su(1,1) and su(2). We also give a kind of factorization formula of the associated Laguerre polynomials.

  97. Calin Buia, Alper Buldum, Jian Ping Lu

    Quantum interference has dramatic effects on electronic transport through nanotube contacts. In optimal configuration the intertube conductance can approach that of a perfect nanotube ($4e^2/h$). The maximum conductance increases rapidly with the contact length up to 10 nm, beyond which it exhibits long wavelength oscillations. This is attributed to the reso

  98. Luis Lehner

    We are entering an era where the numerical construction of generic spacetimes is becoming a reality. The use of computer simulations, in principle, allows us to solve Einstein equations in their full generality and unravel important messages so far hidden in the theory. Despite the problems still found in present applications, significant progress is being a

  99. Sang Pyo Kim, Ademir E. Santana, F. C. Khanna

    Quantum dissipation is studied within two model oscillators, the Caldirola-Kanai (CK) oscillator as an open system with one degree of freedom and the Bateman-Feshbach-Tikochinsky (BFT) oscillator as a closed system with two degrees of freedom. Though these oscillators describe the same classical damped motion, the CK oscillator retains the quantum coherence,

  100. Ayman F. Abouraddy, Kimani C. Toussaint,, Alexander V. Sergienko, Bahaa E. A. Saleh

    Performing reliable measurements in optical metrology, such as those needed in ellipsometry, requires a calibrated source and detector, or a well-characterized reference sample. We present a novel interferometric technique to perform reliable ellipsometric measurements. This technique relies on the use of a non-classical optical source, namely polarization-e