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April 1999 arXiv papers — page 17

Showing 1,6011,700 of 2,121 papers

  1. M. D. Maia

    The algebraic consistency of spin and isospin at the level of an unbroken SU(2) gauge theory suggests the existence of an additional angular momentum besides the spin and isospin and also produces a full quaternionic spinor operator. The latter corresponds to a vector boson in space-time, interpreted as a SU(2) gauge field. The existence of quaternionic spin

  2. Fedele Lizzi, Richard J. Szabo

    A review of the applications of noncommutative geometry to a systematic formulation of duality symmetries in string theory is presented. The spectral triples associated with a lattice vertex operator algebra and the corresponding Dirac-Ramond operators are constructed and shown to naturally incorporate target space and discrete worldsheet dualities as isomet

  3. I. Bars, C. Deliduman, D. Minic

    M-theory has different global supersymmetry structures in its various dual incarnations, as characterized by the M-algebra in 11D, the type IIA, type-IIB, heterotic, type-I extended supersymmetries in 10D, and non-Abelian supersymmetries in the AdS_n x S^m backgrounds. We show that all of these supersymmetries are unified within the supersymmetry OSp(1/64),

  4. G. Giachetta, L. Mangiarotti, G. Sardanashvily

    We study the relationship between the equations of first order Lagrangian field theory on fiber bundles and the covariant Hamilton equations on the finite-dimensional polysymplectic phase space of covariant Hamiltonian field theory. The main peculiarity of these Hamilton equations lies in the fact that, for degenerate systems, they contain additional gauge f

  5. A. Bassetto, R. Begliuomini, G. Nardelli

    We calculate in dimensions $D=2+ε$ and in light-cone gauge (LCG) the perturbative ${\cal O}(g^4)$ contribution to a rectangular Wilson loop in the (t,x)-plane coming from diagrams with a self-energy correction in the vector propagator. In the limit $ε\to 0$ the result is finite, in spite of the vanishing of the triple vector vertex in LCG, and provides the e

  6. Malgorzata Bakalarska, Boguslaw Broda

    A description of the one-loop approximation formula for the partition function of a three-dimensional abelian version of the Donaldson-Witten theory is proposed. The one-loop expression is shown to contain such topological invariants of a three-dimensional manifold M like the Reidemeister-Ray-Singer torsion and Betti numbers.

  7. Mitsuo Abe, Noboru Nakanishi

    In the conformal-gauge two-dimensional quantum gravity, the solution obtained by the perturbative or path-integral approach is compared with the one obtained by the operator-formalism approach. Treatments of the anomaly problem in both approaches are different. This difference is found to be essentially caused by the fact that the perturbative or path-integr

  8. P. Olesen

    We propose the principle that the scale of the glueball masses in the AdS/CFT approach to QCD should be set by the square root of the string tension. It then turns out that the strong bare coupling runs logarithmically with the ultraviolet cutoff T if first order world sheet fluctuations are included. We also point out that in the end, when all corrections a

  9. V. Barger, K. Whisnant

    When three Majorana neutrinos describe the solar and atmospheric neutrino data via oscillations, a nonzero measurement of neutrinoless double beta ($0νββ$) decay can determine the sum of neutrino masses $\sum m_ν$ if the solar solution has small-angle mixing, and place a lower bound on $\sum m_ν$ for large-angle solar mixing. If in addition a nonzero $\sum m

  10. E. Gotsman, E. Levin, U. Maor, E. Naftali

    This paper shows that the approach based on Gribov's ideas for the photon-proton interaction, is able to describe the experimental data over a wide range of photon virtualities $Q^2 = 0 - 100 GeV^2$ and energies $\sqrt{s} = W = 3 - 300 GeV$. A simple model is suggested which provides a quantitative way of describing the matching between short and long di

  11. I. G. Aznauryan

    Within fixed-t dispersion relations the results of new VPI partial-wave analysis for the multipole amplitudes $M_{1+}^{3/2},E_{1+}^{3/2}$ are successfuly described, and the resonance and nonresonance contributions into these amplitudes are separated in correspondence with the interpretation on the language of diagram approach, dynamical models and effective

  12. F. Krauss, R. Kuhn, G. Soff

    We propose a general approach for the description of multijet events in the framework of QCD event generators. We introduce a new algorithm to match parton showers and arbitrary matrix elements for the production of any number of jets via the strong or electroweak interaction. We developped a new parton cascade code capable to deal with multijet events at LE

  13. Yosef Nir

    In the near future, we will have the first significant experimental measurements of CP violation in B decays. These measurements will easily test crucial questions such as whether the Standard Model Kobayashi-Maskawa phase plays a dominant role in CP violation or whether CP is an approximate symmetry in nature. We explain the different types of CP violation

  14. A. Rajantie, M. Hindmarsh

    The time evolution of soft modes in a quantum gauge field theory is to first approximation classical, but the equations of motion are non-local. We show how they can be written in a local and Hamiltonian way in an Abelian theory, and that this formulation is particularly suitable for numerical simulations. This makes it possible to simulate numerically non-e

  15. A. K. Chaudhuri

    We investigate the effect of friction on domain formation in disoriented chiral condensate. Including a friction term, we solve the equation of motion of the linear sigma model fields, in the Hartree approximation. With boost-invariance and cylinderical symmetry, irrespective of friction, on average, we donot find any indication of domain like formation with

  16. R. Casalbuoni, A. Deandrea, S. De Curtis, D. Dominici

    The procedures for studying a single narrow s-channel resonance or nearly degenerate resonances at a lepton collider, especially a muon collider, are discussed. In particular, we examine four methods for determining the parameters of a narrow s-channel resonance: scanning the resonance, measuring the convoluted cross section, measuring the Breit-Wigner area,

  17. Olga Piskounova

    The asymmetries between the spectra of leading and nonleading charmed mesons measured in $Σ^-A$ interactions at $p_L$= 340 GeV/c in the WA89 experiment are described in the framework of Quark-Gluon String Model. There are two versions of the model under consideration: one of them includes the sea charm quark-antiquark pairs and the other one does not. It&#39

  18. Xavier Montes

    We compute the two-point function and the renormalized expectation value of the stress tensor of a quantum field interacting with a nucleating bubble. Two simple models are considered. One is the massless field in the Vilenkin-Ipser-Sikivie spacetime describing the gravitational field of a reflection symmetric domain wall. The other is vacuum decay in flat s

  19. W. Prellier, V. Smolyaninova, Amlan Biswas, C. Galley

    Ceramics of A_{2}FeReO_{6} double-perovskite have been prepared and studied for A=Ba and Ca. Ba_{2}FeReO_{6} has a cubic structure (Fm3m) with $a\approx $8.0854(1) Åwhereas Ca_{2}FeReO_{6} has a distorted monoclinic symmetry with $a\approx 5.396(1) Å, b\approx 5.522(1) Å, c\approx 7.688(2) Å$ and $β=90.4^{\circ} (P21/n)$. The barium compound is metallic from

  20. H. Boyaci, I. O. Kulik

    A generic Hamiltonian, which incorporates the effect of the orbital contraction on the hopping amplitude between the nearest sites, is studied both analytically at the weak coupling limit and numerically at the intermediate and strong coupling regimes for finite atomic cluster. The effect of the orbital contraction due to hole localization at atomic sites is

  21. Shouvik Datta, K. L. Narasimhan

    In this paper, we analyse the optical absorption in porous silicon . This is the first attempt to explicitly demonstrate that it is not possible to extract the band gap of such low dimensional nanostructures like porous silicon from a Tauc plot of Square Root(alpha h nu) vs (h nu) . These objections are also valid for other reduced dimensional systems like q

  22. Joshua L. Cohn

    Measurements of thermal conductivity ($κ$) versus temperature and doping for several cuprate superconductors are discussed. Suppressed values of the normal-state $κ$ and the slope change in $κ$ at $T_c$, observed near 1/8 doping in both YBa$_2$Cu$_3$O$_{6+x}$ and Hg cuprates, are attributed to local lattice distortions and the suppression of the superconduct

  23. Iaroslav Ispolatov

    A convergent approximation is proposed for a mean field density-density correlation function in a system with a two-phase interface. It is based on a fourth-order expansion of the Hamiltonian in terms of fluctuations around the equilibrium profile. The approach is illustrated by one and three dimensional calculations for systems characterized by the Ginzburg

  24. A. Diehl, M. N. Tamashiro, Marcia C. Barbosa, Yan Levin

    We study the interactions between two negatively charged macroscopic surfaces confining positive counterions. A density-functional approach is introduced which, besides the usual mean-field interactions, takes into account the correlations in the positions of counterions. The excess free energy is derived in the framework of the Debye-H{ü}ckel theory of the

  25. Arne Neumayr, Walter Metzner

    Fermion N-loops with an arbitrary number of density vertices N > d+1 in d spatial dimensions can be expressed as a linear combination of (d+1)-loops with coefficients that are rational functions of external momentum and energy variables. A theorem on symmetrized products then implies that divergencies of single loops for low energy and small momenta cancel e

  26. M. Pascaud, G. Montambaux

    We develop a method to calculate the persistent currents and their spatial distribution (and transport properties) on graphs made of quasi-1D diffusive wires. They are directly related to the field derivatives of the determinant of a matrix which describes the topology of the graph. In certain limits, they are obtained by simple counting of the nodes and the

  27. Craig Liu, D. F. Wang

    In this work, we consider the issue of pricing exchange options and spread options with stochastic interest rates. We provide the closed form solution for the exchange option price when interest rate is stochastic. Our result holds when interest rate is modeled with a stochastic term structure of general form, which includes Vasicek model, CIR term structure

  28. M. Dudzinski, G. Fath, J. Sznajd

    The zero temperature phase diagram of a one-dimensional S=2 Heisenberg ferromagnet with single-ion cubic anisotropy is studied numerically using the density-matrix renormalization group method. Evidence is found that although the model does not involve quadrupolar couplings, there is a purely quadrupolar phase for large values of the anisotropy. The phase tr

  29. B. V. Costa, P. Z. Coura, O. N. Mesquita

    We use molecular dynamic to simulate the directional growth of binary mixtures. our results compare very well with analitical and experimental results. This opens up the possibility to probe growth situations which are difficult to reach experimentally, being an important tool for further experimental and theoretical developments in the area of crystal growt

  30. Hiroki Saito, Masahito Ueda

    The second-order coherence of photons scattered from a trapped Bose-Einstein condensate is found to be enhanced for the scattering angles that are either the same or symmetrical with respect to the direction of laser propagation. The enhancement occurs periodically with respect to the time interval between photons, and becomes less and less pronounced with i

  31. Domenico M. Carlucci, Jun-ichi Inoue

    We report on the image reconstruction (IR) problem by making use of the random chiral q-state Potts model, whose Hamiltonian possesses the same gauge invariance as the usual Ising spin glass model. We show that the pixel representation by means of the Potts variables is suitable for the gray-scale level image which can not be represented by the Ising model.

  32. E. A. Kuznetsov, V. P. Ruban

    Vortex line and magnetic line representations are introduced for description of flows in ideal hydrodynamics and MHD, respectively. For incompressible fluids it is shown that the equations of motion for vorticity ${\bf Ω}$ and magnetic field with the help of this transformation follow from the variational principle. By means of this representation it is poss

  33. Gustavo E. Romero, Diego F. Torres, I. Andruchow, Luis A. Anchordoqui

    Based on the study of temporal asymmetry of 631 gamma ray bursts from the BATSE 3B catalog by Link and Epstein [Ap J 466, 764 (1996)], we identify the population of bursts whose rising times are longer than their decays, thus showing atypical profiles. We analyse their sky distribution, morphology, time-space clustering and other average properties and compa

  34. Matthew D. Lehnert, George K. Miley, William B. Sparks, Stefi A. Baum

    We present images taken with the Wide Field Planetary Camera (WFPC-2) on the Hubble Space Telescope of 43 quasars selected from the 3CR radio catalog. The redshift range of the targets is large --- 0.3 < z < 2. These data were taken in the course of a large program that imaged 267 3CR radio galaxies and quasars using the HST in &#34;snapshot mode&#34;. Each

  35. Andrew R. King, Mitchell C. Begelman

    Recent work on Cygnus X-2 suggests that neutron-star or black-hole binaries survive highly super-Eddington mass transfer rates without undergoing common-envelope evolution. We suggest here that the accretion flows in such cases are radiation pressure-dominated versions of the &#34;ADIOS&#34; picture proposed by Blandford and Begelman (1999), in which almost

  36. A. Goldwurm, P. Goldoni, P. Laurent, F. Lebrun

    In spite of increasing evidences of the presence of a massive Black Hole at the Galactic Center, its radio counterpart, Sgr A*, shows little activity at high energies, and recent models involving energy advection (ADAF) have been proposed to explain this difficulty. We present results on the hard X-ray emission from the galactic central square degree obtaine

  37. G. L. Israel, T. Oosterbroek, L. Angelini, S. Campana

    The 8.7s X-ray pulsar 4U 0142+61 was monitored by BeppoSAX between January 1997 and February 1998. This source belongs to the rapidly growing class of &#34;anomalous&#34; X-ray pulsars (AXPs) which have pulse periods in the 6-12s range and no plausible optical, infrared or radio counterparts. The BeppoSAX periods measurements show that 4U 0142+61 continues i

  38. Arthur Kosowsky

    Microwave background polarization, though presently undetected, is a fundamental prediction of any viable cosmological model. These lectures review the theoretical description of polarization, its physical interpretation, and potentially interesting polarization signals.

  39. A. Kurpiewski, M. Jaroszynski

    We study the formation of the spectra in advection dominated accretion flows (ADAFs) around Kerr black holes. We use a Monte Carlo approach and fully general relativistic treatment to follow the paths of individual photons and model their scattering with mildly relativistic, thermal electrons of the two temperature plasma present in the flow. We are mostly i

  40. Kee-Tae Kim, Jeong-Eun Lee, Bon-Chul Koo

    We have carried out high-resolution (~3&#39;) HI and CO line observations along one-dimensional cuts through the Galactic worm GW46.4+5.5. By comparing the HI data with IRAS data, we have derived the distributions of I_100 excess and tau_100 excess, which are respectively the 100 mum intensity and 100 mum optical depth in excess of what would be expected fro

  41. A. Rodriguez-Franco, J. Martin-Pintado, T. L. Wilson

    We present high sensitivity maps of the High Velocity (HV) CO emission toward the molecular outflows around IRc2 and Orion-S in the Orion A molecular cloud. The maps reveal the presence of HV bullets in both outflows with velocities between 40-80kms-1 from the ambient gas velocity. The blue and redshifted CO HV bullets associated with the IRc2 outflow are di

  42. John Richer, Debra Shepherd, Sylvie Cabrit, Rafael Bachiller

    We review some aspects of the bipolar molecular outflow phenomenon. In particular, we compare the morphological properties, energetics and velocity structures of outflows from high and low-mass protostars and investigate to what extent a common source model can explain outflows from sources of very different luminosities. Many flow properties, in particular

  43. Bernd Vollmer, Wolfgang J. Duschl

    We present the results of a re-examination of a [Ne II] line emission data cube (λ12.8 μm) and discuss the kinematic structure of the inner \sim 3 \times 4 pc of the Galaxy. The quality of [Ne II] as a tracer of ionized gas is examined by comparing it to radio data. A three dimensional representation of the data cube allows us to disentangle features which a

  44. S. Chapelon, V. Buat, D. Burgarella, M. Kissler-Patig

    We investigate the globular cluster system around the low-luminosity S0 galaxy NGC 7457 with deep B, V, I photometry. From the V photometry the total number of globular clusters around the galaxy is estimated to be 178 +- 75. The specific frequency is estimated to be S_N = 2.7 +- 1.1 adopting M_V = -19.55 mag for the galaxy. We select 89 globular cluster can

  45. M. Coleman Miller

    The discovery of nearly coherent brightness oscillations during thermonuclear X-ray bursts from six neutron-star low-mass X-ray binaries has opened up a new way to study the propagation of thermonuclear burning, and may ultimately lead to greater understanding of thermonuclear propagation in other astrophysical contexts, such as in Type Ia supernovae. Here w

  46. Peter G. Tuthill, John D. Monnier, William C. Danchi

    Wolf-Rayet (WR) stars are luminous massive blue stars thought to be immediate precursors to the supernova terminating their brief lives. The existence of dust shells around such stars has been enigmatic since their discovery some 30 years ago; the intense radiation field from the star should be inimical to dust survival. Although dust-creation models, includ

  47. Geoffrey C. Bower, Donald C. Backer, Jun-Hui Zhao, Miller Goss

    Synchrotron radiation from active galactic nuclei (AGN) is often highly polarized. We present a search for linear polarization with the Very Large Array (VLA) at 4.8 GHz and 8.4 GHz from the nearest AGN, Sagittarius A*. As a part of this study we used spectro-polarimetric data that were sensitive to a rotation measure (RM) as large as 3.5 x 10^6 rad m^-2 at

  48. Amanda T. Marlowe, Gerhardt R. Meurer, Timothy M. Heckman

    Dwarf galaxies play an important role in our understanding of galaxy formation and evolution, and starbursts are believed to strongly affect their structure and evolution. Here we present a study of 12 of the nearest dwarf galaxies thought to be undergoing starbursts as selected primarily by morphology. We show that these &#34;blue amorphous galaxies&#34; ar

  49. Amitabha Ghosh, Soumitro Banerjee

    The theory of inertial induction, which has been quite successful in explaining a number of hitherto unexplained astrophysical phenomena, predicts a redshift in light grazing massive objects. The total solar eclipse on 11 August 1999 offers an opportunity of testing the theory. In this paper we predict the additional redshift of a few stars during the eclips

  50. Ilaria Musella

    On the basis of new theoretical results useful predictions concerning the Period-Luminosity (PLR) and Period-Luminosity-Color (PLCR) relations both for optical and infrared magnitudes are presented. It is shown that, following the dependence of the instability strip on metallicity, there is a non negligible dependence of the PLRs and PLCRs on the metallicity

  51. Ron Donagi, Burt A. Ovrut, Daniel Waldram

    We present a general method for calculating the moduli spaces of fivebranes wrapped on holomorphic curves in elliptically fibered Calabi-Yau threefolds, in particular, in the context of heterotic M theory. The cases of fivebranes wrapped purely on a fiber curve, purely on a curve in the base and, generically, on a curve with components both in the fiber and

  52. T. Bastin, E. Solano

    We present a novel approach for solving numerically one-dimensional scattering problems and apply it for computing the emission probability of an ultracold atom interacting with an arbitrary field mode of a high-$Q$ cavity. Our method is efficient, stable and succeeds when other numerical integration methods fail. It also replaces and improves advantageously

  53. Gary Shiu, Robert Shrock, S. -H. Henry Tye

    We discuss some collider signatures of the brane world. In addition to the usual bulk (closed string) fields and brane (open string) fields in the Type I string picture, there are closed string fields, namely, twisted modes, which are not confined on the branes but nonetheless are localized in the extra compactified dimensions. While the coupling of the Stan

  54. Ugur Tirnakli, Diego F. Torres

    We develop an analytical technique to derive explicit forms of thermodynamical quantities within the asymptotic approach to non-extensive quantum distribution functions. Using it, we find an expression for the number of particles in a boson system which we compare with other approximate scheme (i.e. factorization approach), and with the recently obtained exa

  55. Victor Yakhot

    Numerical and physical experiments on the forced two-dimensional Navier-Stokes equations show that transverse velocity differences are described by ``normal&#39;&#39; Kolmogorov scaling $<(Δv)^{2n}> \propto r^{2n/3}$ and obey a gaussian statistics. Since the non-trivial scaling is a sign of a strong non-linearity of the problem, these two results seem to con

  56. Harald Dobler, Josef Sollfrank, Ulrich Heinz

    We study the kinetic freeze-out conditions of hadrons in Au+Au collisions at 11.6 A GeV/c using different parametrizations of an expanding thermal fireball. We take into account the available double differential momentum spectra of a variety of particle species, covering a large fraction of the total momentum space. The overall fit to the data is very good a

  57. P. J. Ellis, K. Torikoshi

    The baryon masses are examined in SU(3) chiral perturbation theory to third order using the recently proposed infrared regularization scheme. Fourth order is estimated by evaluating the dominant diagram. With this regularization the magnitude of the loop integrals is reduced so that the convergence of the series appears to be better than in the heavy baryon

  58. T. H. Koornwinder, B. J. Schroers, J. K. Slingerland, F. A. Bais

    A Fourier transform S is defined for the quantum double D(G) of a finite group G. Acting on characters of D(G), S and the central ribbon element of D(G) generate a unitary matrix representation of the group SL(2,Z). The characters form a ring over the integers under both the algebra multiplication and its dual, with the latter encoding the fusion rules of D(

  59. C. J. Villas-Bôas, N. G. de Almeida, M. H. Y. Moussa

    We show how to teleport a running wave superposition of zero- and one-photon field state through the projection synthesis technique. The fidelity of the scheme is computed taking into account the noise introduced by dissipation and the efficiency of the detectors. These error sources have been introduced through a single general relationship between input an

  60. L. Vanel, Ph. Claudin, J. -Ph. Bouchaud, M. E. Cates

    We present precise and reproducible mean pressure measurements at the bottom of a cylindrical granular column. If a constant overload is added, the pressure is linear in overload and nonmonotonic in the column height. The results are {\em quantitatively} consistent with a local, linear relation between stress components, as was recently proposed by some of u

  61. V. Berezinsky

    The current status of oscillation solutions to the Solar Neutrino Problem is reviewed. Four oscillation solutions are discussed in the light of 708d Superkamiokande data: MSW, Just-So VO, VO with Energy-Independent Suppression (EIS) and Resonant-Spin-Flavor-Precession (RSFP). Only EIS VO is strongly disfavoured by the global rates, mostly due to the Homestak

  62. Sandhya Choubey, Srubabati Goswami

    In this paper we do a detailed $χ^2$-analysis of the 848 days of Super-Kamiokande(SK) atmospheric neutrino data under the assumptions of $ν_μ- ν_τ$ oscillation and neutrino decay. For the latter we take the most general case of neutrinos with non-zero mixing and consider the possibilities of the unstable component in $ν_μ$ decaying to a state with which it m

  63. Xiao-Guang Wang, Shao-Hua Pan, Guo-Zhen Yang

    We study the nonclassical properties and algebraic characteristics of the negative binomial states introduced by Barnett recently. The ladder operator formalism and displacement operator formalism of the negative binomial states are found and the algebra involved turns out to be the SU(1,1) Lie algebra via the generalized Holstein-Primarkoff realization. The

  64. J. Fleischer, F. Jegerlehner, M. Tentyukov, O. Veretin

    We evaluate non factorizable $O(αα_s)$ corrections to the process $Z\to b\bar{b}$ due to the virtual t-quark. All two-loop vertex diagrams with $W$&#39;s and charged ghosts $Φ$&#39;s are included. They are evaluated in the large top-mass expansion up to the $10^{th}$ order. Gluon Bremsstrahlung is taken into account by integrating over the whole phase space.

  65. S. Komineas

    Solitons which have the form of a vortex-antivortex pair have recently been found in the Landau-Lifshitz equation which is the standard model for the ferromagnet. We simulate numerically head-on collisions of two vortex-antivortex pairs and observe a right angle scattering pattern. We offer a resolution of this highly nontrivial dynamical behavior by examini

  66. A. Sibirtsev, K. Tsushima, A. W. Thomas

    We examine the production of open charm in antiproton annihilation on finite nuclei. The enhancement of the subthreshold production cross section, even in a nucleus as light as carbon, should provide a clean signature of the reduction in the masses of these mesons in-medium. We also show that a careful analysis of the $D^+$ and $D^-$ spectra can yield import

  67. Christian Jaekel

    We show that the Reeh-Schlieder property w.r.t. the KMS-vector is a direct consequence of locality, additivity and the relativistic KMS-condition. The latter characterises the thermal equilibrium states of a relativistic quantum field theory. The statement remains vaild even if the given equilibrium state breaks spatial translation invariance.

  68. A. Sibirtsev, K. Tsushima, K. Saito, A. W. Thomas

    We make a detailed study of the effect that the recently predicted modification of the in-medium masses of charmed mesons would have on $J/\Psi$ dissociation on pion and $\rho$-meson comovers in relativistic heavy ion collisions. We find a substantial dependence of the $J/\Psi$ absorption rates on the density and temperature of the nuclear matter. This sugge

  69. X. Jehl, P. Payet-Burin, C. Baraduc, R. Calemczuk

    Current noise is measured with a SQUID in low impedance and transparent Nb-Al-Nb j unctions of length comparable to the phase breaking length and much longer than the thermal length. The shot noise amplitude is compared with theoretical predictions of doubled shot noise in diffusive normal/superconductor (NS) junctions due to the Andreev reflections. We disc

  70. Michael Baake, Moritz Hoeffe

    The diffraction of stochastic point sets, both Bernoulli and Markov, and of random tilings with crystallographic symmetries is investigated in rigorous terms. In particular, we derive the diffraction spectrum of 1D random tilings, of stochastic product tilings built from cuboids, and of planar random tilings based on solvable dimer models, augmented by a bri

  71. D. K. Park, Hungsoo Kim, Soo-Young Lee

    The winding number transition in the Mottola-Wipf model with and without Skyrme term is examined. For the model with Skyrme term the number of discrete modes of the fluctuation operator around sphaleron is shown to be dependent on the value of $λm^2$. Following Gorokhov and Blatter we derive a sufficient condition for the sharp first-order transition, which

  72. N. E. Mavromatos, J. Papavassiliou

    In this work we consider a coupled system of Schwinger-Dyson equations for self-energy and vertex functions in QED_3. Using the concept of a semi-amputated vertex function, we manage to decouple the vertex equation and transform it in the infrared into a non-linear differential equation of Emden-Fowler type. Its solution suggests the following picture: in th

  73. Joerg Schumacher, Bruno Eckhardt

    The scaling properties of the second order magnetic structure function D_2^{(B)}(r) and the corresponding magnetic correlation function C_2^{(B)}(r) are derived for two-dimensional magnetohydrodynamic turbulence in the kinematic regime where the ratio of kinetic energy to magnetic energy is much larger than one. In this regime the magnetic flux function $ψ$

  74. Kei-Ichi Kondo

    By making use of the background field method, we derive a novel reformulation of the Yang-Mills theory which was proposed recently by the author to derive quark confinement in QCD. This reformulation identifies the Yang-Mills theory with a deformation of a topological quantum field theory. The relevant background is given by the topologically non-trivial fie

  75. Hsien-chung Kao

    By taking into account the effect of the would be Chern-Simons term, we calculate the quantum correction to the Chern-Simons coefficient in supersymmetric Chern-Simons Higgs theories with matter fields in the fundamental representation of SU(n). Because of supersymmetry, the corrections in the symmetric and Higgs phases are identical. In particular, the corr

  76. Hiroyuki Hata, Sanefumi Moriyama

    We generalize the background gauge in the Matrix model to propose a new gauge which is useful for discussing the conformal symmetry. In this gauge, the special conformal transformation (SCT) as the isometry of the near-horizon geometry of the D-particle solution is directly reproduced with the correct coefficient as the quantum correction to the SCT in the M

  77. G. L. Litvinov, V. P. Maslov, A. Ya. Rodionov

    A unifying approach to software and hardware design generated by ideas of Idempotent Mathematics is discussed. The so-called idempotent correspondence principle for algorithms, programs and hardware units is described. A software project based on this approach is presented. Key words: universal algorithms, idempotent calculus, software design, hardware desig

  78. Vladimir Pestov

    The aim of this paper is to propose a geometric framework for modelling similarity search in large and multidimensional data spaces of general nature, which seems to be flexible enough to address such issues as analysis of complexity, indexability, and the `curse of dimensionality.&#39; Such a framework is provided by the concept of the so-called similarity

  79. Michael M. Kash, Vladimir A. Sautenkov, Alexander S. Zibrov, L. Hollberg

    We report the observation of small group velocities of order 90 meters per second, and large group delays of greater than 0.26 ms, in an optically dense hot rubidium gas (~360 K). Media of this kind yield strong nonlinear interactions between very weak optical fields, and very sharp spectral features. The result is in agreement with previous studies on nonli

  80. A. K. Rajagopal, Sumiyoshi Abe

    The form invariance of the statement of the maximum entropy principle and the metric structure in quantum density matrix theory, when generalized to nonextensive situations, is shown here to determine the structure of the nonextensive entropies. This limits the range of the nonextensivity parameter to so as to preserve the concavity of the entropies. The Tsa

  81. Ali Mostafazadeh

    We outline a method based on successive canonical transformations which yields a product expansion for the evolution operator of a general (possibly non-Hermitian) Hamiltonian. For a class of such Hamiltonians this expansion involves a finite number of terms, and our method gives the exact solution of the corresponding time-dependent Schroedinger equation. W

  82. S. Furuichi, M. Ohya

    Recently, it has been known that a quantum entangled state plays an important role in the field ofquantum information theory such as quantum teleportation and quantum computation. The research on quantifying entangled states has been done by several measures. In this letter, we will adopt the method using quantum mutual entropy to measure the degree of entan

  83. S. A. Markovskii, S. L. Skorokhodov

    Nonlinear evolution of a trans-Alfvenic shock wave (TASW), at which the flow velocity passes over the Alfven velocity, is computed in a magnetohydrodynamic approximation. The analytical theory suggests that an infinitesimal perturbation of a TASW results in its disintegration, i.e., finite variation of the flow, or transformation into some other unsteady con

  84. M. A. Ivanov, Yu. L. Kalinovsky, C. D. Roberts

    An accurate and unified description of the non-hadronic electroweak interactions of light- and heavy-mesons is possible when the dressing of quark propagators and the finite size of hadronic bound states is explicitly accounted for.

  85. Firooz Arash, Shahin Atashbar-Tehrani

    We have used the notion of the constituent quark model of nucleon, where a constituent quark carries its own internal structure, and applied it to determine nuclear structure functions ratios. It is found that the description of experimental data require the inclusion of strong shadowing effect for $x<0.01$. Using the idea of vector meson dominance model and

  86. A. M. Shirokov, N. A. Smirnova, Yu. F. Smirnov, O. Castaños

    A symmetry of the parameter space of interacting boson models IBM-1 and IBM-2 is studied. The symmetry is associated with linear canonical transformations of boson operators, or, equivalently, with the existence of different realizations of the symmetry algebras of the models. The relevance of the parameter symmetry to physical observables is discussed.

  87. R. Bijker, A. Leviatan

    We present a simultaneous analysis of elastic and transition form factors of the nucleon. The calculations are performed in the framework of an algebraic model of baryons. Effects of meson cloud couplings are considered.

  88. Maria Gorelik, Emmanuel Lanzmann

    A well known theorem of Duflo claims that the annihilator of a Verma module in the enveloping algebra of a complex semisimple Lie algebra is generated by its intersection with the centre. For a Lie superalgebra this result fails to be true. For instance, in the case of the orthosymplectic Lie superalgebra osp(1,2), Pinczon gave in [Pi] an example of a Verma

  89. Michael Baake, Robert V. Moody

    Lattices and Z-modules in Euclidean space possess an infinitude of subsets that are images of the original set under similarity transformation. We classify such self-similar images according to their indices for certain 4D examples that are related to 4D root systems, both crystallographic and non-crystallographic. We encapsulate their statistics in terms of

  90. Norbert A&#39;Campo

    Starting from a divide, i.e. a generic immersion of finitely many copies of the interval [0,1] in the disk, we construct a classical link in the 3-sphere. We prove that the link&#39;s complement fibers over the circle, if the divide is connected. Moreover, we compute the monodromy diffeomorphism from the combinatorics of the divide. We added to this version

  91. A. Bohm, H. Kaldass

    The velocity basis of the Poincare group is used in the direct product space of two irreducible unitary representations of the Poincare group. The velocity basis with total angular momentum j will be used for the definition of relativistic Gamow vectors.

  92. R. Dutt, A. Gangopadhyaya, C. Rasinariu, U. Sukhatme

    Differential realizations in coordinate space for deformed Lie algebras with three generators are obtained using bosonic creation and annihilation operators satisfying Heisenberg commutation relations. The unified treatment presented here contains as special cases all previously given coordinate realizations of $so(2,1),so(3)$ and their deformations. Applica

  93. HoSeong La

    Generalizing the geometry of the gauge covariant variables in Yang-Mills theory proposed by Johnson and Haagensen, the 4-d geometry associated with a monopole is defined for SU(2). There are three relevant geometries: AdS$_2\times S^2$, $R^2\times S^2$ and $H_+\times S^2$, depending on the asymptotic behavior of the torsion. Using this geometry, the Wilson l

  94. Martin Gremm, Anton Kapustin

    We construct an N=1 superconformal field theory using branes of type IIA string theory. The IIA construction is related via T-duality to a IIB configuration with 3-branes in a background generated by two intersecting O7-planes and 7-branes. The IIB background can be viewed as a local piece of an F-theory compactification previously studied by Sen in connecti

  95. B. Kleihaus, D. H. Tchrakian, F. Zimmerschied

    The Abelian Higgs model and the Georgi-Glashow model in 2 and 3 Euclidean dimensions respectively, support both finite size instantons and sphalerons. The instantons are the familiar Nielsen-Oleson vortices and the &#39;t Hooft-Polyakov monopole solutions respectively. We have constructed the sphaleron solutions and calculated the Chern-Simons charges N_cs f

  96. Christian Jaekel

    The basic ingredients of Tomita-Takesaki modular theory are used to establish cluster estimates. Applications to thermal quantum field theory are discussed.

  97. Kingman Cheung

    Gravity can become strong at the TeV scale in the theory of extra dimensions. An effective Lagrangian can be used to describe the gravitational interactions below a cut-off scale. In this work, we study the diphoton production in $γγ$, $p\bar p$, and $e^+ e^-$ collisions in the model of low scale gravity. Since in the standard model photon-photon scattering

  98. Peter Lichard

    We investigate the mechanism of K+ -> pi+ l+ l- (l= e, mu) decays in which a virtual photon is emitted either from the incoming K+ or the outgoing pi+. We point out some inconsistencies with and between two previous calculations, discuss the possible experimental inputs, and estimate the branching fractions. This mechanism alone fails to explain the existing

  99. Firooz Arash, Ali Naghi Khorramia

    We have improved and examined the applicability of the valon model where the structure of any hadron is determined by the structure of its constituent quarks. Nucleon structure functions are calculated within this model in the Next-to-Leading order. The results compare well with the experimental data. The model handles the bound state problem and the calcula

  100. V. Dmitrašinović

    Starting from the historical Fermi four-fermion low-energy effective electroweak interactions Lagrangian for the third generation of quarks, augmented by an NJL type interaction responsible for dynamical symmetry breaking and heavy quark mass generation, and fixing the scalar (Higgs) field v.e.v. at v = 247 GeV, we show that: (1) heavy quark bound states Q\b