Skip to content

April 2000 arXiv papers — page 5

Showing 401–500 of 2,147 papers

  1. Youngman Kim, Mannque Rho

    We study the competition between induced symmetry breaking (ISB), Cooper pairing (superconductivity) and chiral condensation at finite non-asymptotic density. Using a quantum mechanical model studied recently by Ilieva and Thirring, we analyze the expectation value of the fermion number density $\la a^*a\ra$ in the presence of chemical potential and discuss

  2. Phung Ho Hai

    We show that, with some technical conditions, an abelian category can be embedded into the category of bimodules over a ring. The case of semisimple rigid monoidal categories is studied in more detail.

  3. Jim Bryan, Ron Donagi, Naichung Conan Leung

    We study the moduli space M(G,A) of flat G-bundles on an Abelian surface A, where G is a compact, simple, simply connected, connected Lie group. Equivalently, M(G,A) is the (coarse) moduli space of s-equivalence classes of holomorphic semi-stable G_C-bundles with trivial Chern classes where G_C is the complexified group. M(G,A) has the structure of a hyperka

  4. Razvan Gelca

    In previous joint work with Frohman and Lofaro a noncommutative generalization of the A-polynomial of a knot was introduced, consisting of a finitely generated ideal of polynomials (the noncommutative A-ideal) in the quantum plane. The present paper shows that the noncommutative A-ideal of a knot, together with finitely many of its colored Jones polynomials

  5. Dan Burns, Yi Hu, Tie Luo

    We show that any birational map between projective hyperKähler manifolds of dimension 4 is composed of a sequence of simple flops or elementary Mukai transformations under the assumption that each irreducible component of the indeterminacy of the birational map is normal.

  6. Branko Saric

    Analogously to the concept of a curvature of curve and surface, in the differential geometry, in the main part of this paper the concept of the curvature of the hyper-dimensional vector spaces of Riemannian metric is generally defined. The defined concept of the curvature of Riemannian spaces of higher dimensions M: M>1, in the further text of the paper, is

  7. Branko Saric

    In the introduction part of this paper, first of all, the concept of absolute integral sum of complex function is defined, as more general one with respect to the concept of integral as well as of integral sum of "ordinary'' integral calculus. In the main part of the paper, on the basis of redefined concepts of a spatial derivative as well as of

  8. Andrei Zelevinsky

    Double Bruhat cells in a semisimple group are intersections of cells in two Bruhat decompositions corresponding to two opposite Borel subgroups. They form a geometric framework for the study of total positivity in semisimple groups; they are also closely related to symplectic leaves in the corresponding Poisson-Lie groups. The term "cells" might be m

  9. Mauricio Cataldo, Alberto Garcia

    (2+1)-regular static black hole solutions with a nonlinear electric field are derived. The source to the Einstein equations is an energy momentum tensor of nonlinear electrodynamics, which satisfies the weak energy conditions and in the weak field limit becomes the (2+1)-Maxwell field tensor. The derived class of solutions is regular; the metric, curvature i

  10. Harald Grosse, Edwin Langmann

    We find a large class of quantum gauge models with massless fermions where the coupling to the gauge fields is not chirally symmetric and which nevertheless do not suffer from gauge anomalies. To be specific we study two dimensional Abelian models in the Hamiltonian framework which can be constructed and solved by standard techniques. The general model descr

  11. Alexander Turbiner

    A certain notion of canonical equivalence in quantum mechanics is proposed. It is used to relate quantal systems with discrete ones. Discrete systems canonically equivalent to the celebrated harmonic oscillator as well as the quartic and the quasi-exactly-solvable anharmonic oscillators are found. They can be viewed as a translation-covariant discretization

  12. Theodora Ioannidou

    Atiyah and Manton have outlined a scheme to obtain approximations to the SU(2) skyrmions from instantons in $\R^4$. In this paper we apply this scheme to construct, in an explicit form, approximations to static spherically symmetric SU(N) skyrmions with various baryon numbers. In particular we show how to obtain the skyrmions from instantons using harmonic m

  13. H. Ikemori, S. Kitakado, H. Otsu, T. Sato

    Quantum mechanics on sphere $S^{n}$ is studied from the viewpoint that the Berry's connection has to appear as a topological term in the effective action. Furthermore we show that this term is the Chern-Simons term of gauge variables that correspond to the extra degrees of freedom of the enlarged space.

  14. Nathan Berkovits, Brenno Carlini Vallilo

    Using pure spinors, the superstring was recently quantized in a manifestly ten-dimensional super-Poincaré covariant manner and a covariant prescription was given for tree-level scattering amplitudes. In this paper, we prove that this prescription is cyclically symmetric and, for the scattering of an arbitrary number of massless bosons and up to four massless

  15. A. V. Bratchikov

    We use the conformal Ward identities to study the structure of correlation functions in coset conformal field theories. For a large class of primary fields of arbitrary g/h theory a factorization anzatz is found.Corresponding correlation functions are explicitly expressed in terms of correlation functions of two independent WZNW theories for g and h.

  16. Kaushik Bhattacharya, Palash B. Pal

    We calculate the cross section of the inverse beta decay process, $ν_e+n\to p+e$, in a magnetic field which is much smaller than $m_p^2/e$. Using exact solutions of the Dirac equation in a constant magnetic field, we find that the cross section depends on the direction of the incident neutrino even when the initial neutron is assumed to be at rest. We discus

  17. M. M. Block, F. Halzen, T. Stanev

    We simultaneously fit a QCD-inspired parameterization of all accelerator data on forward proton-proton and antiproton-proton scattering amplitudes, together with cosmic ray data (using Glauber theory), to predict proton-air and proton-proton cross sections at energies near \sqrt s \approx 30 TeV. The p-air cosmic ray measurements provide a strong constraint

  18. A. Widom, Y. N. Srivastava

    The decay of the Higgs particle into two gravitons was previously calculated by us using a Born term from the Einstein field equations. Subsequently, others computed the same decay via one loop diagrams but omitting the Born terms. Here all of the diagrams up to one loop are discussed, and it is shown that the Born term is overwhelmingly dominant in agreemen

  19. A. Sornborger, M. Parry

    Systems that exhibit pattern formation are typically driven and dissipative. In the early universe, parametric resonance can drive explosive particle production called preheating. The fields that are populated then decay quantum mechanically if their particles are unstable. Thus, during preheating, a driven-dissipative system exists. We have shown previously

  20. Eric Braaten, Jungil Lee

    The short-distance coefficients for the color-octet 3S1 term in the fragmentation function for a gluon to split into heavy quarkonium states is calculated to order alpha_s^2. The gauge-invariant definition of the fragmentation function by Collins and Soper is employed. Ultraviolet divergences are removed using the MS-bar renormalization procedure. The longit

  21. H. Sazdjian

    Pionium lifetime corrections to the nonrelativistic formula are calculated in the framework of the quasipotential-constraint theory approach. The calculation extends an earlier evaluation, made in the scheme of standard chiral perturbation theory, to the scheme of generalized chiral perturbation theory, in which the quark condensate is left as a free paramet

  22. Christian Beck

    We generalize Hagedorn's statistical theory of momentum spectra of particles produced in high-energy collisions using Tsallis' formalism of non-extensive statistical mechanics. Suitable non-extensive grand canonical partition functions are introduced for both fermions and bosons. Average occupation numbers and moments of transverse momenta are evalua

  23. Peter Lichard, Julia Thompson

    The rate of the beta decay of neutral kaons is calculated within the meson dominance approach taking into account the relation between the KKρand ππρcoupling constants which follows from the vector meson dominance in electromagnetic interactions and isospin symmetry. The decay rate transforms into the following branching fraction summed over the charge state

  24. Wojciech Krolikowski

    An algebraic argument based on a series of generalized Dirac equations, truncated by an "intrinsic Pauli principle", shows that there should exist two sterile neutrinos as well as three families of leptons and quarks. Then, the influence of these additional neutrinos on neutrino oscillations is studied. As an example, a specific model of effective fi

  25. B. S. Zou, H. B. Li, representing BES Collaboration

    $J/Ψ$ particles are abundantly produced at the Beijing Electron Positron Collider (BEPC). The $J/Ψ$ decays provide an excellent place for studying $N^*$ resonances. For $J/Ψ\to\bar NNπ$ and $\bar NNππ$, the $πN$ and $ππN$ systems are limited to be pure isospin 1/2 due to isospin conservation. This is a big advantage in studying $N^*$ resonances from $J/Ψ$ de

  26. S. Chaturvedi, N. Mukunda

    A unified approach to parametrization of the mixing matrix for $N$ generations is developed. This approach not only has a clear geometrical underpinning but also has the advantage of being economical and recursive and leads in a natural way to the known phenomenologically useful parametrizations of the mixing matrix.

  27. Y. Iwasaki, K. Kanaya, S. Kaya, T. Yoshié

    We study the nature of the QCD vacuum at general number of flavors $N_F$ by numerical simulations on the lattice. Combining the results with those of the perturbation theory, we propose the following picture: 1) For $N_F \ge 17$, there exists only one IR fixed point at vanishing gauge coupling, i.e., the theory in the continuum limit is trivial. 2) For $16 \

  28. Hideo Nakajima, Sadataka Furui

    The first test of the Kugo-Ojima colour confinement criterion by the lattice Landau gauge QCD simulation is performed. The parameter u which is expected to be -1δ^a_b in the continuum theory was found to be -0.7δ^a_b in the strong coupling region. The data is analyzed in connection with the theory of Zwanziger. In the weak coupling region, the expectation va

  29. R. A. Briere, CLEO Collaboration

    A study of charm fragmentation into $D_s^{*+}$ and $D_s^+$ in $e^+e^-$ annihilations at $\sqrt{s}$=10.5 GeV is presented. This study using $4.72 \pm 0.05$ fb$^{-1}$ of CLEO II data reports measurements of the cross-sections $σ(D_s^{*+})$ and $σ(D_s^+)$ in momentum regions above $x=0.44$, where $x$ is the $D_s$ momentum divided by the maximum kinematically al

  30. SLD Collaboration

    We present a measurement of the left-right cross-section asymmetry (ALR) for Z boson production by e+e- collisions. The measurement includes the final data taken with the SLD detector at the SLAC Linear Collider (SLC) during the period 1996-1998. Using a sample of 383,487 Z decays collected during the 1996-1998 runs we measure the pole-value of the asymmetry

  31. I. G. Alekseev, P. E. Budkovsky, V. P. Kanavets, L. I. Koroleva

    The ITEP-PNPI collaboration presents the results of the measurements of the spin rotation parameter A in the elastic scattering of positive and negative pions on protons at P_beam = 1.62 GeV/c. The setup included a longitudinally-polarized proton target with superconductive magnet, multiwire spark chambers and a carbon polarimeter with thick filter. Results

  32. S. N. Coppersmith, Leo P. Kadanoff, Zhitong Zhang

    We consider a class of models describing the dynamics of $N$ Boolean variables, where the time evolution of each depends on the values of $K$ of the other variables. Previous work has considered models with dissipative dynamics. Here we consider time-reversible models, which necessarily have the property that every possible point in the state-space is an ele

  33. S. M. Badalyan

    Carrier interaction with phonons, photons, impurities, and electrons have been addressed in semiconductor nanoscale systems with carrier confinement in one and two dimensions subjected to a quantizing magnetic field and without it.

  34. V. A. Stephanovich

    We predict the existence of Griffith phase in the dielectrics with concentrational crossover between dipole glass (electric analog of spin glass) and ferroelectricity. The peculiar representatives of above substances are $KTaO_3:Li$, $Nb$, $Na$ or relaxor ferroelectrics like $Pb_{1-x}La_xZr_{0.65}Ti_{0.35}O_3$. Since this phase exists above ferroelectric pha

  35. N. Lecocq, N. Vandewalle

    The self-stratification of binary and ternary granular mixtures has been experimentally investigated. Ternary mixtures lead to a particular ordering of the strates which was not accounted for in former explanations. Bouncing grains are found to have an important effect on strate formation. A complementary mechanism for self-stratification of binary and terna

  36. Laurent Proville, Serge Aubry

    We study the effective mass of the bipolarons and essentially the possibility to get both light and strongly bound bipolarons in the Holstein-Hubbard model and some variations in the vicinity of the adiabatic limit. Several approaches to investigate the quantum mobility of polarons and bipolarons are proposed for this model. It is found that the bipolaron ma

  37. Laurent Proville, Serge Aubry

    The spatially localized bound states of two electrons in the adiabatic two-dimensional Holstein-Hubbard model on a square lattice are investigated both numerically and analytically. The interplay between the electron-phonon coupling g, which tends to form bipolarons and the repulsive Hubbard interaction $\upsilon \geq 0$, which tends to break them, generates

  38. S. Sasaki, S. De Franceschi, J. M. Elzerman, W. G. van der Wiel

    The Kondo effect is a key many-body phenomenon in condensed matter physics. It concerns the interaction between a localised spin and free electrons. Discovered in metals containing small amounts of magnetic impurities, it is now a fundamental mechanism in a wide class of correlated electron systems. Control over single, localised spins has become relevant al

  39. Patrik Henelius, A. V. Balatsky, J. R. Schrieffer

    We discuss the effects of magnetic impurities on d-wave superconductors. We calculate the electron mediated RKKY interaction between the impurity spins in a d-wave superconductor and find that it decays as $r^{-3}$ at large distances. We argue that this interaction leads to the formation of a spin glass at low temperature $T \ll T_c$. It was previously shown

  40. V. Yushankhai, M. Wolf, K. -H. Mueller, R. Hayn

    The antiferromagnetic insulating cuprate Ba$_3$Cu$_2$O$_4$Cl$_2$ contains folded CuO$_2$ chains with four magnetic copper ions ($S=1/2$) per unit cell. An underlying multiorbital Hubbard model is formulated and the superexchange theory is developed to derive an effective spin Hamiltonian for this cuprate. The resulting spin Hamiltonian involves a Dzyaloshins

  41. M. Ya. Amusia, V. R. Shaginyan

    In the context of the density functional theory we consider the single particle excitation spectra of electron systems. As a result, we have related the single particle excitations with the eigenvalues of the corresponding Kohn-Sham equations. In a case when the exchange correlation functional is approximated by the exchange functional the coupling equations

  42. Raul Donangelo, Alex Hansen, Kim Sneppen, Sergio R. Souza

    We consider a market where many agents trade many different types of products with each other. We model development of collective modes in this market, and quantify these by fluctuations that scale with time with a Hurst exponent of about 0.7. We demonstrate that individual products in the model occationally become globally accepted means of exchange, and si

  43. D. B. Saakian

    We calculate moments of free energy's finite size correction for the transition point between ferromagnetic and spin glass phases. We find, that those moments scale with the number of spins with different critical indices, characteristic for the multiscaling. This critical point corresponds to threshold of errorless coding for a gaussian noisy channel. W

  44. Claudius Gros, Roser Valenti, J. V. Alvarez, Kay Hamacher

    Recent experimental evidence suggest the existence of three distinct V-valence states (V^{+4}, V^{+4.5} and V^{+5}) in the low-temperature phase of NaV_2O_5 in apparent discrepancy with the observed spin-gap. We investigate a novel spin cluster model, consisting of weakly coupled, frustrated four-spin clusters aligned along the crystallographic b-axis that w

  45. Keith Slevin, Tomi Ohtsuki, Tohru Kawarabayashi

    The boundary condition dependence of the critical behavior for the three dimensional Anderson transition is investigated. A strong dependence of the scaling function and the critical conductance distribution on the boundary conditions is found, while the critical disorder and critical exponent are found to be independent of the boundary conditions.

  46. Karl D. Rakos, James M. Schombert, Andrew P. Odell, Susanna Steindling

    This paper presents four color narrow-band photometry of clusters A115 ($z=0.191$) and A2283 ($z=0.182$) in order to follow the star formation history of various galaxy types. Although located at similar redshifts, the two clusters display very different fractions of blue galaxies (i.e. the Butcher-Oemler effect, $f_B = 0.13$ for A115, $f_B = 0.30$ for A2283

  47. Ramiro de la Reza, Licio da Silva, Natalia A. Drake, Marco A. Terra

    First-ascent red giants with strong and very strong Li lines have just been discovered in globular clusters. Using the stellar internal prompt 7Li enrichment - mass loss scenario, we explore the possibility of 7Li enrichment in the interstellar matter of the globular cluster M3 produced by these Li-rich giants. We found that enrichment as large as 70% or mor

  48. William F. Welsh, Edward L. Robinson, Patrick Young

    We obtained R- and I-band CCD photometry of the soft X-ray transient/neutron- star binary Aql X-1 in 1998 June while it was at quiescence. We find that its light curve is dominated by ellipsoidal variations, although the ellipsoidal variations are severely distorted and have unequal maxima. After we correct for the contaminating flux from a field star locate

  49. Agnieszka Janiuk, Bozena Czerny, Aneta Siemiginowska, Marek A. Abramowicz

    We analyse the radiation pressure instability of the standard, optically thisc disc and propose it as an explanation of the obseved variability of the superluminal microquasar GRS 1915+105. The quantitave agreement with the observed outburst amplitudes is obtained under the assumption that substantial part of the energy is carried away by the jet.

  50. Esteban Roulet

    The evolution of the observational results of microlensing towards the LMC and some of the suggested interpretations to account for them are discussed. It is emphasized that the results at present are indicative of a lensing population of white dwarfs, possibly in the spheroid (not dark halo) of the Galaxy, together with the more standard backgrounds of stel

  51. Licia Verde

    Following the discovery of the CMB, the hot big-bang model has become the standard cosmological model. In this theory, small primordial fluctuations are subsequently amplified by gravity to form the large-scale structure seen today. Different theories for unified models of particle physics, lead to different predictions for the statistical properties of the

  52. Martha P. Haynes, Katherine P. Jore, Elizabeth A. Barrett, Adrick H. Broeils

    BVRI and H-alpha imaging and long-slit optical spectroscopic data are presented for four morphologically normal and relatively isolated Sa galaxies, NGC3626, NGC3900, NGC4772 and NGC5854. VLA HI synthesis imaging is presented for the first 3 objects. In all 4 galaxies, evidence of kinematic decoupling of ionized gas components is found; the degree and circum

  53. R. D. Jeffries, E. J. Totten, D. J. James

    We present high resolution spectroscopy of a sample of 24 solar-type stars in the young (15-40 Myr), open cluster, NGC 2547. We use our spectra to confirm cluster membership in 23 of these stars, determine projected equatorial velocities and chromospheric activity, and to search for the presence of accretion discs. We have found examples of both fast (vsini>

  54. G. Ostlin

    I present the first results from a HST/NICMOS imaging study of the most metal-poor blue compact dwarf galaxy IZw18. The near infrared color-magnitude diagram (CMD) is dominated by two populations, one 10-20 Myr population of red super giants and one 0.5-5 Gyr population of asymptotic giant branch stars. Stars older than 1 Gyr are required to explain the obse

  55. T. Idiart, F. Thevenin

    Abundances of alpha-elements such as Ca and Mg in disk and halo stars are usually derived from equivalent widths lines measured on high resolution spectra, and assuming Local Thermodynamic Equilibrium (LTE) . In this paper, we present non-LTE differential abundances derived by computing the statistical equilibrium of CaI and MgI atoms, using high resolution

  56. Andrei Gruzinov, Peter Meszaros

    MeV seed photons produced in shocks in a variable ultra-relativistic outflow gain energy by the Fermi mechanism, because the photons Compton scatter off relativistically colliding shells. The Fermi-modified high-energy photon spectrum has a non-universal slope and a universal cutoff. A significant increase in the total radiative efficiency is possible. In so

  57. H. M. Antia, Sarbani Basu

    The temporal variations of the rotation rate in the solar interior are studied using frequency splittings from Global Oscillations Network Group (GONG) data obtained during the period 1995-99. We find alternating latitudinal bands of faster and slower rotation which appear to move towards the equator with time - similar to the torsional oscillations seen at

  58. T. Matos, L. A. Urena-Lopez

    Continuing with previous works, we present a cosmological model in which dark matter and dark energy are modeled by scalar fields $Φ$ and $Ψ$, respectively, endowed with the scalar potentials $V(Φ)=V_{o}[ \cosh {(λ\sqrt{κ_{o}}Φ)}-1] $ and $\tilde{V}(Ψ)=\tilde{V_{o}}[ \sinh {(α\sqrt{κ_{o}}Ψ)}] ^β$. This model contains 95% of scalar field. We obtain that the s

  59. A. Sedrakian, I. Wasserman

    We study the perturbation modes of rotating superfluid ellipsoidal figures of equilibrium in the framework of the two-fluid superfluid hydrodynamics and Newtonian gravity. Our calculations focus on linear perturbations of background equilibria in which the two fluids move together, the total density is uniform, and the densities of the two components are pro

  60. Mary K. Gaillard, Brent Nelson

    We calculate the one-loop quantum contributions to soft supersymmetry breaking terms in the scalar potential in supergravity theories regulated à la Pauli-Villars. We find ``universal'' contributions, independent of the regulator masses and tree level soft supersymmetry breaking, that contribute gaugino masses and A-terms equal to the ``anomaly media

  61. Daniel Boer

    We investigate a helicity non-flip double transverse spin asymmetry in vector boson production in hadron-hadron scattering, which was first considered by Ralston and Soper at the tree level. It does not involve transversity functions and in principle also arises in W-boson production for which we present the expressions. The asymmetry requires observing the

  62. C. Knigge, K. S. Long, D. W. Hoard, P. Szkody

    We present the ultraviolet spectrum of the SW Sex star and nova-like variable DW UMa in an optical low state, as observed with the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope (HST). The data are well described by a synthetic white dwarf (WD) spectrum with T_eff = 46,000 +/- 1000 K, log g = 7.60 +/- 0.15, v*sin(i) = 370 +/- 100 km

  63. Roberto A. Monetti, Ezequiel V. Albano

    First- and second-order temperature driven transitions are studied, in a lattice gas driven by an oscillatory field. The short time dynamics study provides upper and lower bounds for the first-order transition points obtained using standard simulations. The difference between upper and lower bounds is a measure for the strength of the first-order transition

  64. Yi-hong Gao, Gang Tian

    We search for an abelian description of the Yang-Mills instantons on certain eight dimensional manifolds with the special holonomies $Spin(7)$ and SU(4). By mimicing the Seiberg-Witten theory in four dimensions, we propose a set of monopole-like equations governing the 8-dimensional U(1) connections and spinors, which are supposed to be the dual theory of th

  65. Roy Maartens

    In Randall-Sundrum-type brane-world cosmologies, the dynamical equations on the three-brane differ from the general relativity equations by terms that carry the effects of imbedding and of the free gravitational field in the five-dimensional bulk. We derive the covariant nonlinear dynamical equations for the gravitational and matter fields on the brane, and

  66. José S. Andrade,, Sergey V. Buldyrev, Nikolay V. Dokholyan, Shlomo Havlin

    We study the flow of fluid in porous media in dimensions $d=2$ and 3. The medium is modeled by bond percolation on a lattice of $L^d$ sites, while the flow front is modeled by tracer particles driven by a pressure difference between two fixed sites (``wells'') separated by Euclidean distance $r$. We investigate the distribution function of the shorte

  67. Sidney Bludman, Matts Roos

    For a flat universe presently dominated by smooth energy, either cosmological constant (LCDM) or quintessence (QCDM), we calculate the asymptotic collapsed mass fraction as function of the present ratio of smooth energy to matter energy $\mathcal R_0$. Identifying the normalized collapsed fraction as a conditional probability for habitable galaxies, we obser

  68. I. M. Dremin, J. W. Gary

    We review results on hadron multiplicities in high energy particle collisions. Both theory and experiment are discussed. The general procedures used to describe particle multiplicity in Quantum Chromodynamics (QCD) are summarized. The QCD equations for the generating functions of the multiplicity distributions are presented both for fixed and running couplin

  69. Takashi Tamaki, Takashi Torii

    We construct static and spherically symmetric particle-like and black hole solutions with magnetic or electric charge in the Einstein-Born-Infeld-dilaton system, which is a generalization of the Einstein-Maxwell-dilaton (EMD) system and of the Einstein-Born-Infeld (EBI) system. They have remarkable properties which are not seen for the corresponding solution

  70. Hideo Kodama, Akihiro Ishibashi, Osamu Seto

    In the present paper the gauge-invariant formalism is developed for perturbations of the brane-world model in which our universe is realized as a boundary of a higher-dimensional spacetime. For the background model in which the bulk spacetime is $(n+m)$-dimensional and has the spatial symmetry corresponding to the isometry group of a $n$-dimensional maximall

  71. L. Anton

    We show that a noncollapsing solution below r_c can be constructed for the dynamics of randomly forced particle interacting with a dissipative boundary. The scaling analysis predicts a divergent collision rate at the boundary for the noncollapsing solution. This prediction is tested numerically.

  72. I. Antoniadis, E. Kiritsis, T. Tomaras

    We propose a minimal embedding of the Standard Model spectrum in a D-brane configuration of type I string theory. The SU(3) color and SU(2) weak interactions arise from two different collections of branes. The model is neither grand unified nor supersymmetric but it naturally leads to the right prediction of the weak angle for a string scale of the order of

  73. C. D. Lu, K. Ukai, M. Z. Yang

    We calculate the branching ratios and CP asymmetries for B^0 to pi^+pi^-, B^+ to pi^+pi^0 and B^0 to pi^0pi^0 decays, in a perturbative QCD approach. In this approach, we calculate non-factorizable and annihilation type contributions, in addition to the usual factorizable contributions. We found that the annihilation diagram contributions are not very small

  74. K. -I. Kondo, T. Shinohara

    We show that off-diagonal gluons and off-diagonal ghosts acquire their masses dynamically in QCD if the maximal Abelian gauge is adopted. This result strongly supports the Abelian dominance in low-energy region of QCD. The mass generation is shown to occur due to ghost-anti-ghost condensation caused by attractive quartic ghost interactions within the Abelian

  75. Soon-Tae Hong, Won Tae Kim, Young-Jai Park, Myung Seok Yoon

    We study noncommutative geometry in the framework of the Batalin-Fradkin-Tyutin(BFT) scheme, which converts second class constraint system into first class one. In an open string theory noncommutative geometry appears due to the mixed boundary conditions having second class constraints, which arise in string theory with $D$-branes under a constant Neveu-Schw

  76. S. V. Molodtsov, A. M. Snigirev, G. M. Zinovjev

    The selfconsistent approach to the quark interactions in the instanton liquid is developed within the tadpole approximation calculating the basic functional integral. The effective Lagrangian obtained includes colourless scalar field interacting with quarks. The origin of this dynamical field as an interaction carrier in soft momentum region is discussed.

  77. Jerome Benoit, Rossen Dandoloff

    Using group theoretical methods we show for both the triangular and square lattices that in the continuum limit the antiferromagnetic order parameter lives on SO3 without respect of the initial lattice. For the antiferromagnetic chain we recover the Haldane decomposition. This order parameter interacts with a local gauge field rather than with a global one a

  78. S. Hashimoto, K-I. Ishikawa, T. Onogi, M. Sakamoto

    We calculate perturbative renormalization constants for the ΔB=2 four-quark operators in lattice NRQCD. Continuum operators \bar{b}γ_μ(1-γ_5)q~ \bar{b}γ_μ(1-γ_5)q and \bar{b}(1-γ_5)q~\bar{b}(1-γ_5)q, which are necessary in evaluating the mass and width differences in $B^0_{d(s)}-\bar{B}^0_{d(s)}$ systems, are matched at one-loop with corresponding lattice op

  79. Jin Young Kim

    We consider the cosmological evolution of the three-brane in the background of type IIB string theory. For two different backgrounds which give nontrivial dilaton profile we have derived the Friedman-like equations. These give the cosmological evolution which is similar to the one by matter density on the universe brane. The effective density blows up as we

  80. Louisa A. Nolan, James S. Dunlop, Raul Jimenez

    Given sufficiently deep optical spectroscopy, the age estimation of high-redshif t ($z > 1$) galaxies has been claimed to be a relatively robust process (e.g. Dunlop et al. 1996) due to the fact that, for ages $< 5$Gyr, the near-ultraviolet light of a stellar population is expected to be dominated by `well-understood&#39; main-sequence (MS) stars. Recently,

  81. Stephen A. Fenner

    We present new intuition behind Grover&#39;s quantum search algorithm by means of a Hamiltonian. Given a black-box Boolean function f mapping strings of length n into {0,1} such that f(w) = 1 for exactly one string w, L. K. Grover describes a quantum algorithm that finds w in O(2^{n/2}) time. Farhi & Gutmann show that w can also be found in the same amount t

  82. Richard MacKenzie

    These lectures are intended as an introduction to the technique of path integrals and their applications in physics. The audience is mainly first-year graduate students, and it is assumed that the reader has a good foundation in quantum mechanics. No prior exposure to path integrals is assumed, however. The path integral is a formulation of quantum mechanics

  83. C. S. Unnikrishnan

    The formalism employing local complex amplitudes that resolved the Einstein-Podolsky-Rosen puzzle (C. S. Unnikrishnan, quant-ph/0001112) is applied to the three-particle GHZ correlations. We show that the GHZ quantum correlations can be reproduced without nonlocality.

  84. M. Shurgalin, W. H. Parkinson, K. Yoshino, C. Schoene

    Experimental apparatus and measurement technique are described for precision absorption measurements in sodium - noble gas mixtures. The absolute absorption coefficient is measured in the wavelength range from 425 nm to 760 nm with 2% uncertainty and spectral resolution of 0.02 nm. The precision is achieved by using a specially designed absorption cell with

  85. Naftali Tishby, Fernando C. Pereira, William Bialek

    We define the relevant information in a signal $x\in X$ as being the information that this signal provides about another signal $y\in \Y$. Examples include the information that face images provide about the names of the people portrayed, or the information that speech sounds provide about the words spoken. Understanding the signal $x$ requires more than just

  86. Philip R. Page

    We discuss whether a low-lying hybrid baryon should be defined as a three quark - gluon bound state or as three quarks moving on an excited adiabatic potential. We show that the latter definition becomes exact, not only for very heavy quarks, but also for specific dynamics. We review the literature on the signatures of hybrid baryons, with specific reference

  87. Alex Kasman

    Recent interest in discrete, classical integrable systems has focused on their connection to quantum integrable systems via the Bethe equations. In this note, solutions to the rational nested Bethe ansatz (RNBA) equations are constructed using the ``completed Calogero-Moser phase space&#39;&#39; of matrices which satisfy a finite dimensional analogue of the

  88. Frederic Helein, Joseph Kouneiher

    We discuss in this paper the canonical structure of classical field theory in finite dimensions within the {\it{pataplectic}} hamiltonian formulation, where we put forward the role of Legendre correspondance. We define the Poisson $\mathfrak{p}$-brackets and $\mathfrakω$-brackets which are the analogues of the Poisson bracket on forms. We formulate the equat

  89. Francesco Mercuri, Paolo Piccione, Daniel V. Tausk

    We investigate the problem of the stability of the number of conjugate or focal points (counted with multiplicity) along a semi-Riemannian geodesic $γ$. For a Riemannian or a non spacelike Lorentzian geodesic, such number is equal to the intersection number (Maslov index) of a continuous curve with a subvariety of codimension one of the Lagrangian Grassmanni

  90. Feng Xu

    We formulate the unitary rational orbifold conformal field theories in the algebraic quantum field theory framework. Under general conditions, we show that the orbifold of a given unitary rational conformal field theories generates a unitary modular category. Many new unitary modular categories are obtained. We also show that the irreducible representations

  91. Daniel Goldston, C. Y. Yildirim

    Assuming the Generalized Riemann Hypothesis, we obtain a lower bound within a constant factor of the conjectured asymptotic result for the second moment for primes in an individual arithmetic progression in short intervals. Previous results were averaged over all progression of a given modulus. The method uses a short divisor sum approximation for the von Ma

  92. Diarmuid Crowley, Christine M. Escher

    We classify the total spaces of bundles over the four sphere with fiber a three sphere up to orientation preserving and reversing homotopy equivalence, homeomorphism and diffeomorphism. These total spaces have been of interest to both topologists and geometers. It has recently been shown by Grove and Ziller that each of these total spaces admits metrics with

  93. Narcisse Randrianantoanina

    Let $\M$ be a semi-finite von Neumann algebra equipped with a faithful normal trace $τ$. We study the subspace structures of non-commutative Lorentz spaces $L_{p,q}(\M, τ)$, extending results of Carothers and Dilworth to the non-commutative settings. In particular, we show that, under natural conditions on indices, $\ell_p$ can not be embedded into $L_{p,q}(

  94. Narcisse Randrianantoanina

    We prove that a Banach space $E$ has the compact range property (CRP) if and only if for any given $C^*$-algebra $\cal A$, every absolutely summing operator from $\cal A$ into $E$ is compact.

  95. Narcisse Randrianantoanina

    Let $\cal M$ be a semi-finite von Neumann algebra equipped with a distinguished faithful, normal, semi-finite trace $τ$. We introduce the notion of equi-integrability in non-commutative spaces and show that if a rearrangement invariant quasi-Banach function space $E$ on the positive semi-axis is $α$-convex with constant 1 and satisfies a non-trivial lower $q

  96. Micho Durdevich

    A general theory of quantum spinor structures on quantum spaces is presented, within the conceptual framework of the formalism of quantum principal bundles. Quantum analogs of all basic objects of the classical theory are constructed and analyzed. This includes Laplace and Dirac operators, quantum versions of Clifford and spinor bundles, a Hodge *-operator,

  97. V. Tarasov, A. Varchenko

    The trigonometric KZ equations associated with a Lie algebra $\g$ depend on a parameter $λ\in\h$ where $\h\subset\g$ is the Cartan subalgebra. We suggest a system of dynamical difference equations with respect to $λ$ compatible with the KZ equations. The dynamical equations are constructed in terms of intertwining operators of $\g$-modules.

  98. A. C. R. Mendes, W. Oliveira, F. I. Takakura

    Hydrodynamic turbulence is studied as a constrained system from the point of view of metafluid dynamics. We present a Lagrangian description for this new theory of turbulence inspired from the analogy with electromagnetism. Consequently it is a gauge theory. This new approach to the study of turbulence tends to renew the optimism to solve the difficult probl

  99. M. Gomes, L. C. Malacarne, A. J. da Silva

    We study the low energy regime of the scattering of two fermionic particles carrying isospin 1/2 and interacting through a non-Abelian Chern-Simons field. We calculate the one-loop scattering amplitude for both the nonrelativistic and also for the relativistic theory. In the relativistic case we introduce an intermediate cutoff, separating the regions with l

  100. E. Dudas, J. Mourad

    The tachyon-free nonsupersymmetric string theories in ten dimensions have dilaton tadpoles which forbid a Minkowski vacuum. We determine the maximally symmetric backgrounds for the $USp(32)$ Type I string and the $SO(16)\times SO(16)$ heterotic string. The static solutions exhibit nine dimensional Poincaré symmetry and have finite 9D Planck and Yang-Mills co