March 1998 arXiv papers — page 10

V. Sahni

We probe gravitational clustering in N-body simulations using geometrical descriptors sensitive to `connectedness': the genus curve, percolation and shape statistics. We find that both genus and percolation curves provide complementary probes of large scale structure topology and could be used to discriminate between models of structure formation and the

Andrei Gruzinov, Wayne Hu

In a universe reionized in patches, the Doppler effect from Thomson scattering off free electrons generates secondary cosmic microwave background (CMB) anisotropies. For a simple model with small patches and late reionization, we analytically calculate the anisotropy power spectrum. Patchy reionization can, in principle, be the main source of anisotropies on

E. Abdalla, N. Afshordi, K. Khodjasteh, R. Mohayaee

We write a non-relativistic Lagrangian for a hierarchical universe. The equations of motion are solved numerically and the evolution of the fractal dimension is obtained for different initial conditions. We show that our model is homogeneous at the time of the last scattering, but evolves into a self-similar universe with a remarkably constant fractal dimens

H. Burkhardt, J. Lowe, G. J. Stephenson, T. Goldman

Some consequences of the oscillations of neutral kaons and neutrinos are discussed, in particular, the possibility of oscillations of particles recoiling against kaons or neutrinos from the production process. We show that there are no stationary oscillations of these recoil particles in any order, and that the apparent long-wavelength oscillations, which mi

Edward Witten

The correspondence between supergravity (and string theory) on $AdS$ space and boundary conformal field theory relates the thermodynamics of ${\cal N}=4$ super Yang-Mills theory in four dimensions to the thermodynamics of Schwarzschild black holes in Anti-de Sitter space. In this description, quantum phenomena such as the spontaneous breaking of the center o

S. Marculescu, F. Ruiz Ruiz

A model for the diffusion of vector fields driven by external forces is proposed. Using the renormalization group and the $ε$-expansion, the dynamical critical properties of the model with gaussian noise for dimensions below the critical dimension are investigated and new transport universality classes are obtained.

A. A. Penin, A. A. Pivovarov

A correlator of the vector current of a heavy quark is computed analytically near threshold in the next-to-next-to-leading order in perturbative and relativistic expansion that includes $\al_s^2$, $\al_sv$ and $v^2$ corrections in the coupling constant and velocity of the heavy quark to the nonrelativistic Coulomb approximation. Based on this result, the num

A. Fierro, G. Franzese, A. de Candia, A. Coniglio

We numerically study the dynamical properties of fully frustrated models in 2 and 3 dimensions. The results obtained support the hypothesis that the percolation transition of the Kasteleyn-Fortuin clusters corresponds to the onset of stretched exponential autocorrelation functions in systems without disorder. This dynamical behavior may be due to the ``large

M. V. Simkin, E. G. D. Cohen

Three hyperfine states of Bose-condensed sodium atoms, recently optically trapped, can be described as a spin-1 Bose gas. We study the behaviour of this system in a magnetic field, and construct the phase diagram, where the temperature of the Bose condensation $T_{BEC}$ increases with magnetic field. In particular the system is ferromagnetic below $T_{BEC}$

G. Fiorentini, E. Lisi, Subir Sarkar, F. L. Villante

We present a simple method for determining the (correlated) uncertainties of the light element abundances expected from big bang nucleosynthesis, which avoids the need for lengthy Monte Carlo simulations. Our approach helps to clarify the role of the different nuclear reactions contributing to a particular elemental abundance and makes it easy to implement e

P. H. Damgaard, U. M. Heller, A. Krasnitz, T. Madsen

Three-dimensional lattice QCD is studied by Monte Carlo simulations within the quenched approximation. At zero temperature a quark-antiquark condensate is observed in the limit of vanishing quark masses. The condensate vanishes continuously at the finite-temperature deconfinement phase transition of the theory. A natural interpretation of this phenomenon in

J. Houdayer, J. H. Boutet de Monvel, O. C. Martin

Combinatorial optimization is a fertile testing ground for statistical physics methods developed in the context of disordered systems, allowing one to confront theoretical mean field predictions with actual properties of finite dimensional systems. Our focus here is on minimum matching problems, because they are computationally tractable while both frustrate

Enrico Carlon, Andrzej Drzewinski, Jos Rogiers

We consider an Ising model confined in an $L \times \infty$ geometry with identical surface fields at the boundaries. According to the Kelvin equation the bulk coexistence field scales as 1/L for large L; thermodynamics and scaling arguments predict higher order corrections of the type $1/L^2$ and $1/L^{5/3}$ at partial and complete wetting respectively. Our

Koji Hashimoto, Hiroyuki Hata, Naoki Sasakura

We construct BPS saturated regular configurations of N=4 SU(3) supersymmetric Yang-Mills theory carrying non-parallel electric and magnetic charges. These field theory BPS states correspond to the string theory BPS states of 3-string junctions connecting three different D3-branes by regarding the N=4 supersymmetric Yang-Mills theory as an effective field the

Katsushi Ito, Sung-Kil Yang

We present a simple proof of the WDVV equations for the prepotential of four-dimensional N=2 supersymmetric Yang-Mills theory with all ADE gauge groups. According to our proof it is clearly seen that the WDVV equations in four dimensions have their origin in the associativity of the chiral ring in two-dimensional topological Landau-Ginzburg models. The WDVV

F. Araki, M. Musakhanov, H. Toki

In this letter we focus on the calculation of $f_{η'}^{(c)},$ the amplitude of the $ (c\bar{c}) \to (gluons) \to η^{'}$ transition, which provides the magnitude of the contribution of the Cabbibo favored $b \to \bar c c s$ elementary process to $B \to η' K$ decay. It is found that $f_{η'}^{(c)} = - 12.3\sim -18.4 MeV$ on the scale of $m_{c}.$

John K. Webb, Victor V. Flambaum, Christopher W. Churchill, Michael J. Drinkwater

A method offering an order of magnitude sensitivity gain is described for using quasar spectra to investigate possible time or space variation in the fine structure constant, alpha. Applying the technique to a sample of 30 absorption systems, spanning redshifts 0.5 < z< 1.6, obtained with the Keck I telescope, we derive limits on variations in alpha over a w

Salman Habib, Kosuke Shizume, Wojciech Hubert Zurek

We present evidence that decoherence can produce a smooth quantum-to-classical transition in nonlinear dynamical systems. High-resolution tracking of quantum and classical evolutions reveals differences in expectation values of corresponding observables. Solutions of master equations demonstrate that decoherence destroys quantum interference in Wigner distri

M. Murao, P. L. Knight

The decoherence of nonclassical motional states of a trapped $^9 {\rm Be^+}$ ion in a recent experiment is investigated theoretically. Sources of decoherence considered here destroy the characteristic coherent quantum dynamics of the system but do not cause energy dissipation. Here they are first introduced phenomenologically and then described using a micro

Andreas Mielke

Continuous unitary transformations can be used to diagonalize or approximately diagonalize a given Hamiltonian. In the last four years, this method has been applied to a variety of models of condensed matter physics and field theory. With a new generator for the continuous unitary transformation proposed in this paper one can avoid some of the problems of fo

P. Fonte, R. Ferreira-Marques, Y. Ivaniouchenkov, V. Peskov

In this work we describe a parallel geometry gaseous detector constituted by a thin (0.6 mm) amplifying gap preceded by a drift region. The gap is delimited by a metal plate and by a wire mesh. The detector can count up to a rate of 10^7 Hz/mm2 at gain 1000 and retains at lower counting rates the high gains (close to 10^6) that are typical of parallel geomet

Victor V. Batyrev

Using non-Archimedian integration over spaces of arcs of algebraic varieties, we define stringy Euler numbers associated with arbitrary Kawamata log terminal pairs. There is a natural Kawamata log terminal pair corresponding to an algebraic variety V having a regular action of a finite group G. In this situation we show that the stringy Euler number of this

Cesar Bautista

A generalized Hopf algebra structure for the positive (negative) part of the Drinfeld-Jimbo quantum group of type A_n is established without make any use of the usual deformation of the abelian part of sl_{n+1}.

Druel Stephane

The aim of this paper is to find all algebraic threefolds admitting quasi-regular Poisson structure. There are three types of such varieties: abelian varieties, smooth flat conic bundles over abelian surfaces and quotients of the product of a curve and a symplectic surface by a finite group.

M. J. Hopkins, J. H. Palmieri, J. H. Smith

We show that in a generalized Adams spectral sequence, the presence of a vanishing line of fixed slope (at some term of the spectral sequence, with some intercept) is a generic property.

D. J. Broadhurst

We develop ladders that reduce $ζ(n):=\sum_{k>0}k^{-n}$, for $n=3,5,7,9,11$, and $β(n):=\sum_{k\ge0}(-1)^k(2k+1)^{-n}$, for $n=2,4,6$, to convergent polylogarithms and products of powers of $π$ and $\log2$. Rapid computability results because the required arguments of ${\rm Li}_n(z)=\sum_{k>0}z^k/k^n$ satisfy $z^8=1/16^p$, with $p=1,3,5$. We prove that $G:=β

Wolfgang Ebeling

We describe a relation between Arnold&#39;s strange duality and a polar duality between the Newton polytopes which is mostly due to M.~Kobayashi. We show that this relation continues to hold for the extension of Arnold&#39;s strange duality found by C.~T.~C.~Wall and the author. By a method of Ehlers-Varchenko, the characteristic polynomial of the monodromy

J. Grundberg, J. Wirstam

We calculate finite temperature effects on a correlation function in the two dimensional supersymmetric nonlinear O(3) sigma model. The correlation function violates chiral symmetry and at zero temperature it has been shown to be a constant, which gives rise to a double-valued condensate. Within the bilinear approximation we find an exact result in a one-ins

P. Ruelle, O. Verhoeven

We classify the possible discrete (finite) symmetries of two--dimensional critical models described by unitary minimal conformally invariant theories. We find that all but six models have the group Z_2 as maximal symmetry. Among the six exceptional theories, four have no symmetry at all, while the other two are the familiar critical and tricritical 3--Potts

G. Longhi, M. Materassi

A canonical realization of the BMS (Bondi-Metzner-Sachs) algebra is given on the phase space of the classical real Klein-Gordon field . By assuming the finiteness of the generators of the Poincaré group, it is shown that a countable set of conserved quantities exists (supertranslations); this set transforms under a particular Lorentz representation, which is

V. I. Shevchenko, Yu. A. Simonov

A contour gauge of general type is analysed where 1-form (vector potential) is expressed as a contour integral of the 2-form (field strength) along an arbitrary contour $C$. For a special class of contours the gauge condition reduces to $k_μ(x) A_μ(x) = 0 $ where $k_μ(x)$ is a tangent vector to the contour $C$. A simple proof of the nonabelian Stokes theorem

A. Makhlin, E. Surdutovich

We study the dynamics of quantum fluctuations which take place at the earliest stage of high-energy processes and the conditions under which the data from e-p deep-inelastic scattering may serve as an input for computing the initial data for heavy-ion collisions at high energies. Our method is essentially based on the space-time picture of these seemingly di

Marco A. Diaz, M. A. Garcia-Jareno, Diego A. Restrepo, J. W. F. Valle

We perform a careful study of the neutral scalar sector of a model which includes a singlet, a doublet, and a triplet scalar field under $SU(2)$. This model is motivated by neutrino physics, since it is simply the most general version of the seesaw model of neutrino mass generation through spontaneous violation of lepton number. The neutral Higgs sector cont

M. Casu, L. M. Sehgal

We have recently examined the static properties of the baryon octet (magnetic moments and axial vector coupling constants) in a generalized quark model in which the angular momentum of a polarized nucleon is partly spin $\langle S_z \rangle$ and partly orbital $\langle L_z \rangle$. The orbital momentum was represented by the rotation of a flux-tube connecti

Chia-Hung V. Chang, Darwin Chang, We-Fu Chang, Hsiang-nan Li

We calculate the semileptonic branching ratio and the charm counting of inclusive $B$ meson decays using the perturbative QCD formalism. For the nonleptonic decays, we employ the modified factorization theorem, in which Wilson coefficients evolve with the characteristic scales of the decay modes. It is found that the decay rate of the single-charm mode $b\to

S. Kumano, K. Umekawa

Nuclear parton distributions are studied in a parton model with rescaling and recombination mechanisms. Parton x distributions are first calculated at Q^2=1 GeV^2 by the model, and they are evolved to larger Q^2 in order to be compared with various F_2 data. The experimental shadowing is explained by the parton-recombination effects. Then, the modification o

Manuela Campanelli, Carlos O. Lousto, John Baker, Gaurav Khanna

We solve the problem of expressing the Weyl scalars $ψ$ that describe gravitational perturbations of a Kerr black hole in terms of Cauchy data. To do so we use geometrical identities (like the Gauss-Codazzi relations) as well as Einstein equations. We are able to explicitly express $ψ$ and $\partial _tψ$ as functions only of the extrinsic curvature and the t

Kristen Menou, Eliot Quataert, Ramesh Narayan

Astronomers have discovered many potential black holes in X-ray binaries and galactic nuclei. These black holes are usually identified by the fact that they are too massive to be neutron stars. Until recently, however, there was no convincing evidence that the objects identified as black hole candidates actually have event horizons. This has changed with ext

Dmitri Khokhlov

The quantum theory of gravity is considered based on the assumption that gravitational interaction occurs by means of the vector field of the Planck mass. Gravitational emission is considered as a process of the decay of proton into some matter fields at the Planck scale. Within the framework of grand unification vector field of the Planck mass may be though

Andrzej Królak

We present two statistical tests for periodicities in the time series. We apply the two tests to the data taken from Glasgow prototype interferometer in March 1996. We find that the data contain several very narrow spectral features. We investigate whether these features can be confused with gravitational wave signals from pulsars.

D. D. Bowman, G. Ouillon, C. G. Sammis, A. Sornette

We test the concept that seismicity prior to a large earthquake can be understood in terms of the statistical physics of a critical phase transition. In this model, the cumulative seismic strain release increases as a power-law time-to-failure before the final event. Furthermore, the region of correlated seismicity predicted by this model is much greater tha

M. Quijada, J. Cerne, J. R. Simpson, H. D. Drew

We report on the optical properties of the hole-doped manganites Nd_{0.7}Sr _{0.3}MnO_{3}, La_{0.7}Ca_{0.3}MnO_{3}, and La_{0.7}Sr_{0.3}MnO_{3}. The low-energy optical conductivity in the paramagnetic-insulating state of these materials is characterized by a broad maximum near 1 eV. This feature shifts to lower energy and grows in optical oscillator strength

E. A. Dorofeev, S. I. Matveenko

We consider two-dimensional system of particles localized on randomly distributed sites of squared lattice with anisotropic transfer matrix elements between localized sites. By summing of &#34;diffusion ladder&#34; and &#34;cooperon ladder&#34; type vertices we calculated the conductivity for various sites and particles densities.

S. Clarke, J. E. Inglesfield, M. Nekovee, P. K. de Boer

The charge on an atom at a metallic surface in an electric field is defined as the field-derivative of the force on the atom, and this is consistent with definitions of effective charge and screening charge. This charge can be found from the shift in the potential outside the surface when the atoms are moved. This is used to study forces and screening on sur

M. E. Cates, J. Wittmer, J. P. Bouchaud, P. Claudin

We consider materials whose mechanical integrity is the result of a jamming process. We argue that such media are generically &#34;fragile&#34;: unable to support certain types of incremental loading without plastic rearrangement. Fragility is linked to the marginal stability of force chain networks within the material. Such ideas may be relevant to jammed c

Paulo S. Kuhn, Yan Levin, Marcia C. Barbosa

We investigate the properties of rigid polyelectrolyte solutions in presence of monovalent salt. The free energy within the Debye-Hückel-Bjerrum (DHBj) theory [M. E. Fisher and Y. Levin, {\it Phys. Rev. Lett.} 71, 3826 (1993)] is constructed. It is found that at thermodynamic equilibrium the polyelectrolyte solution consists of clusters composed of one polyi

Stefan Albrecht, Lucia Reining, Rodolfo Del Sole, Giovanni Onida

An ab initio approach to the calculation of excitonic effects in the optical absorption spectra of semiconductors and insulators is formulated. It starts from a quasiparticle bandstructure calculation and is based on the relevant Bethe--Salpeter equation. An application to bulk silicon shows a substantial improvement with respect to previous calculations in

T. Kawarabayashi, B. Kramer, T. Ohtsuki

The Anderson transition in three dimensions in a randomly varying magnetic flux is investigated in detail by means of the transfer matrix method with high accuracy. Both, systems with and without an additional random scalar potential are considered. We find a critical exponent of $ν=1.45\pm0.09$ with random scalar potential. Without it, $ν$ is smaller but in

Gaurav Dar, Mahendra K. Verma, V. Eswaran

In this paper we study the effect of subtle changes in initial conditions on the evolution of global quantities in two-dimensional Magnetohydrodynamic (MHD) turbulence. We find that a change in the initial phases of complex Fourier modes of the Elsässer variables, while keeping the initial values of total energy, cross helicity and Alfvén ratio unchanged, ha

John J Cowan, Christopher Sneden, James W Truran, Debra L Burris

Ground- and space-based observations of stellar heavy element abundances are providing a clearer picture of the chemical evolution of the Galaxy. A large number of (r)apid and (s)low neutron capture process elements, including the first Hubble Space Telescope observations of Pt, Os, Pb and Ge, have been identified in metal-poor, galactic halo stars. In the v

Timothy M. Heckman, Carmelle Robert, Claus Leitherer, Donald R. Garnett

We report the results of a systematic study of the vacuum-ultraviolet spectra of 45 starburst and related galaxies observed with the IUE satellite. These span broad ranges in metallicity, bolometric luminosity, and galaxy properties. The projected size of the IUE spectroscopic aperture is typically one to several kpc and therefore usually encompasses the ent

Christian Knigge, Mario Livio

Blue- and red-shifted Hydrogen and Helium satellite recombination lines have recently been discovered in the optical spectra of at least two supersoft X-ray sources (SSSs), RX J0513-069 and RX J0019.8+2156, and tentatively also in one short-period cataclysmic variable star (CV), the recurrent nova T Pyx. These features are thought to provide evidence for the

R. Srianand, Gopal-Krishna

According to a currently popular paradigm, nuclear activity in quasars is sustained via accretion of material onto super-massive black holes located at the quasar nuclei. A useful tracer of the gravitational field in the vicinity of such central black holes is available in the form of extremely dense gas clouds within the broad emission-line region (BLR) on

N. Wex, S. Johnston, R. N. Manchester, A. G. Lyne

The pulsar PSR B1259-63 is in a highly eccentric 3.4-yr orbit with the Be star SS 2883. Timing observations of this pulsar, made over a 7-yr period using the Parkes 64-m radio telescope, cover two periastron passages, in 1990 August and 1994 January. The timing data cannot be fitted by the normal pulsar and Keplerian binary parameters. A timing solution incl

K. Z. Stanek, D. Zaritsky, J. Harris

Following an approach developed by Paczyński & Stanek, we derive a distance to the Large Magellanic Cloud (LMC) by comparing red clump stars from the Hipparcos catalog with the red clump stars observed in two fields in the LMC that were selected from the ongoing photometric survey of the Magellanic Clouds to lie in low extinction regions. The use of red clum

J. M. Solanes, P. Stein

We report radial velocities for 99 galaxies with projected positions within 30 arcmin of the center of the cluster A3733 obtained with the MEFOS multifiber spectrograph at the 3.6-m ESO telescope. These measurements are combined with 39 redshifts previously published by Stein (1996) to built a collection of 112 galaxy redshifts in the field of A3733, which i

C. P. Dullemond, R. Turolla

The existence of bimodal disks is investigated. Following a simple argument based on energetic considerations we show that stationary, bimodal accretion disk models in which a Shakura--Sunyaev disk (SSD) at large radii matches an advection dominated accretion flow (ADAF) at smaller radii are never possible using the standard slim disk approach, unless some e

Z. I. Tsvetanov, M. G. Allen, H. C. Ford, R. J. Harms

A deep, fuly sampled diffraction limited (FWHM ~ 70 mas) narrow-band image of the central region in M87 was obtained with the Wide Filed and Planetary Camera 2 of the Hubble Space Telescope using the dithering technique. The H-alpha+[NII] continuum subtracted image reveals a wealth of details in the gaseous disk structure described earlier by Ford et al. (19

K. T. S. Brazier, S. Johnston

We collate the evidence for rotation-powered neutron stars that are visible as X-ray sources and not as radio pulsars. Quantitative upper limits exist for the radio fluxes of eight objects, revealing a population at least an order of magnitude less luminous at radio wavelengths than known radio pulsars of similar power or age. These objects could have intrin

L. Metcalfe, B. Altieri, H. Aussel, A. Biviano

We report on the mid-IR imaging at 7 and 10 microns of the galaxy cluster Abell 370, obtained with the ISOCAM instrument onboard ESA&#39;s Infrared Space Observatory (ISO), as part of an ongoing program to image gravitational arcs and arclets in distant clusters. We have recorded initial detections of the A0 giant arc in both bandpasses, the two central domi

Xue-Bing Wu

The conventional thermal instability criterion can not be applied to the advection-dominated accretion disks around black holes where the radiative cooling is insufficient to balance the viscous heating. The surface density change associated with the temperature perturbations, which was usually neglected in deriving the conventional criterion, was recently s

L. R. Abramo, N. C. Tsamis, R. P. Woodard

We derive the implications for anisotropies in the cosmic microwave background following from a model of inflation in which a bare cosmological constant is gradually screened by an infrared process in quantum gravity. The model predicts that the amplitude of scalar perturbations is $A_S = (2.0 \pm .2) \times 10^{-5}$, that the tensor-to-scalar ratio is $r \a

R. Tantalo, C. Chiosi, A. Bressan

Systematic variations in the line strength indices H_beta, Mg2, and <Fe> are observed across elliptical galaxies and from one object to another. Furthermore arguments are given for an enhancement of Mg (\alfa in general) with respect to Fe toward the center of these galaxies. In this study we have investigated the ability of the H_beta, Mg2 and <Fe> diagnost

Victor V. Batyrev

We introduce the notion of stringy E-function for an arbitrary normal irreducible algebraic variety X with at worst log-terminal singularities. We prove some basic properties of stringy E-functions and compute them explicitly for arbitrary Q-Gorenstein toric varieties. Using stringy E-functions, we propose a general method to define stringy Hodge numbers for

Victor V. Batyrev

Let X and Y be two smooth projective n-dimensional algebraic varieties X and Y over C with trivial canonical line bundles. We use methods of p-adic analysis on algebraic varieties over local number fields to prove that if X and Y are birational, they have the same Betti numbers.

C. M. Hull

Limits of a system of N Dn-branes in which the bulk and string degrees of freedom decouple to leave a `matter&#39; theory are investigated and, for n>4, either give a free theory or require taking $N \to \infty$. The decoupled matter theory is described at low energies by the $N \to \infty$ limit of n+1 dimensional \sym, and at high energies by a free type I

Takashi Yokono

We consider brane configurations in elliptic models which represent softly broken N=4 USp(2 N_c) and SO(N_c) theory. We generalize the notion of the O4 plane, so that it is compatible with the symmetry in the covering space of the elliptic models. By using this notion of the O4 plane, we find the curve for softly broken N=4 USp(2 N_c) and that for SO(N_c) th

David P. DiVincenzo, Christopher A. Fuchs, Hideo Mabuchi, John A. Smolin

The newfound importance of ``entanglement as a resource&#39;&#39; in quantum computation and quantum communication compels us to quantify it in as many distinct ways as possible. Here we explore a new measure of entanglement for mixed quantum states of bipartite systems, which we name the Entanglement of Assistance. We show it to be the maximum average entan

Shahar Gov, Shmuel Shtrikman, Harry Thomas

In this paper we analyze the dynamic stability of the hovering magnetic top from first principles without using any preliminary assumptions. We write down the equations of motion for all six degrees of freedom and solve them analytically around the equilibrium solution. Using this solution we then find conditions which the height of the hovering top above th

Sa Ben-Hao, Tai An, Wang Hui, Liu Feng-He

The proposed hadronic and string cascade model, JPCIAE, for ultrarelativistic nucleus - nucleus collisions based on the LUND model and the PYTHIA event generator especially, is used to investigate the $J/ψ$ suppression due to the nuclear absorption of a $J/ψ$ in minimum bias pA and BA collisions at 200 A GeV energy. With the different sets of reasonable form

Zoltán Balogh, Sheldon W. Davis, Winfried Just, Saharon Shelah

A combinatorial principle CECA is formulated and its equivalence with GCH+ certain weakenings of Box_lambda for singular lambda is proved. CECA is used to show that certain ``almost point- < tau&#39;&#39; families can be refined to point- < tau families by removing a small set from each member of the family. This theorem in turn is used to show the consisten

A. Nowicki

We consider two realizations of the $κ$-deformed phase space obtained as a cross product algebra extension of $k$-Poincaré algebra. Two kinds of the kappa-deformed uncertainty relations are briefly discussed.

A. P. Balachandran, S. Vaidya

It is well-known that the winding number of the Skyrmion can be identified as the baryon number. We show in this paper that this result can also be established using the Atiyah-Singer index theorem and spectral flow arguments. We argue that this proof suggests that there are light quarks moving in the field of the Skyrmion. We then show that if these light d

Z. C. Wu

In the no-boundary univers e the universe is created from an instanton. However, there does not exist any instanton for the ``realistic&#39;&#39; $FRW$ universe with a scalar field. The ``instanton&#39;&#39; leading to its quantum creation may be modified and reinterpreted as a constrained gravitational instanton.

Tao Han

We study the possible experimental signatures resulting from a strongly-interacting electroweak sector at $e^-e^-$ colliders, emphasizing the signal enhancement by high beam polarization. We also discuss the unique role for operating the collider in $e^-γ$ mode to produce a heavy isosinglet vector state $ω_T$.

Antonio Riotto

We reanalyze the issue of generation of the baryon asymmetry at the electroweak phase transition in the MSSM and compute the baryon asymmetry assuming the presence of non-trivial CP-violating phases in the parameters associated with the left-right stop mixing term and the Higgsino mass $μ$. Making use of the closed time-path (CTP) formalism of nonequilibrium

M. Axenides, L. Perivolaropoulos, T. Tomaras

Global and local symmetries may or may not be restored inside topological defects depending upon the values of the parameters of the model. A detailed study of this parameter dependence of the core structure of strings and monopoles is presented in the context of simple models.

A. Johansen, D. Sornette

Discrete scale invariance, which corresponds to a partial breaking of the scaling symmetry, is reflected in the existence of a hierarchy of characteristic scales l0, c l0, c^2 l0,... where c is a preferred scaling ratio and l0 a microscopic cut-off. Signatures of discrete scale invariance have recently been found in a variety of systems ranging from rupture,

Omri Gat, Itamar Procaccia, Reuven Zeitak

We present a numerical method which is used to calculate anomalous scaling exponents of structure functions in the Kraichnan passive scalar advection model (R. H. Kraichnan, Phys. Fluids {\bf11}, 945 (1968)). This Monte-Carlo method, which is applicable in any space dimension, is based on the Lagrangian path interpretation of passive scalar dynamics, and use

Y. Akutsu, N. Akutsu, T. Yamamoto

Below the roughening temperature, the equilibrium crystal shape (ECS) is composed of both facets and a smoothly curved surface. As for the ``normal&#39;&#39; profile (perpendicular to the facet contour), the ECS has the exponent 3/2 which is characteristic of systems in the Gruber-Mullins-Pokrovsky-Talapov (GMPT) universality class. Quite recently,it was poi

Mahendra K. Verma

In this paper we construct a self-consistent renormalization group procedure for MHD turbulence in which small wavenumber modes are averaged out, and effective mean magnetic field at large wavenumbers is obtained. In this scheme the mean magnetic field scales as $k^{-1/3}$, while the energy spectrum scales as $k^{-5/3}$ similar to that in fluid turbulence. W

Ralf Klessen, Andreas Burkert

The isothermal gravitational collapse and fragmentation of a molecular cloud region and the subsequent formation of a protostellar cluster is investigated numerically. The clump mass spectrum which forms during the fragmentation phase can be well approximated by a power law distribution dN/dM ~ M^(-1.5). In contrast, the mass spectrum of protostellar cores t

I. V. Moskalenko, W. Collmar, V. Schoenfelder

We use recent data obtained by three (OSSE, BATSE, and COMPTEL) of four instruments on board the Compton Gamma Ray Observatory, to construct a model of Cyg X-1 which describes its emission in a broad energy range from soft X-rays to MeV gamma-rays self-consistently. The gamma-ray emission is interpreted to be the result of Comptonization, bremsstrahlung, and

Y. Ohyama Y. Taniguchi

We report results of $^{12}$CO ($J=1$-0) mapping observations of the Wolf-Rayet starburst galaxy Mrk 1259 which has optical evidence for the superwind seen from a nearly pole-on view. The CO emission is detected in the central 4 kpc region. The nuclear CO spectrum shows a blue-shifted ($ΔV \simeq -27$ km s$^{-1}$) broad (FWHM $\simeq$ 114 km s$^{-1}$) compon

Marc Kamionkowski

Forthcoming cosmic microwave background experiments (CMB) will provide precise new tests of structure-formation theories. The geometry of the Universe may be determined robustly, and the classical cosmological parameters, such as the cosmological constant, baryon density, and Hubble constant, may be determined as well. In addition, the ``inflationary observa

Alberto J. Castro-Tirado

Since their discovery in 1973, Gamma-Ray Bursts (GRBs) have remained for many years one of the most elusive mysteries in High Energy-Astrophysics. The main problem regarding the nature of GRBs has usually been the lack of knowledge of their distance scale. About 300 GRBs are detected annually by BATSE in the full sky, but only a few of them can be localized

Jacek Dziarmaga

A quench in an underdamped one dimensional $ϕ^4$ model is studied by analytical methods. The density of kinks just after the transition is proportional to the square root of the rate of the quench for slow quenches. If the quench is shorter that the relaxation time, then the density scales like the third root of the rate.

Daksh Lohiya, Meetu Sethi

A search for a problem free cosmology within the framework of an effective non - minimally coupled scalar tensor theory is suggested. With appropriate choice of couplings in variants of a Lee - Wick model [as also in a model supporting Q - ball solutions], non topological solutions [NTS&#39;s], varying in size upto 10 kpc to 1 Mpc can exist. We explore the p

K. Held, D. Vollhardt

The importance of Hund&#39;s rule coupling for the stabilization of itinerant ferromagnetism is investigated within a two-band Hubbard model. The magnetic phase diagram is calculated by finite-temperature quantum Monte Carlo simulations within the dynamical mean-field theory. Ferromagnetism is found in a broad range of electron fillings whereas antiferromagn

John W. Barrett

The evaluation of a relativistic spin network for the classical case of the Lie group SU(2) is given by an integral formula over copies of SU(2). For the graph determined by a 4-simplex this gives the evaluation as an integral over a space of geometries for a 4-simplex.

Anatoly Svidzinsky, Alexander Fetter

A hydrodynamic description is used to study the normal modes of a vortex in a zero-temperature Bose-Einstein condensate. In the Thomas-Fermi (TF) limit, the circulating superfluid velocity far from the vortex core provides a small perturbation that splits the originally degenerate normal modes of a vortex-free condensate. The relative frequency shifts are sm

Pankaj Jain, John P. Ralston

Radiation traversing the observable universe provides powerful ways to probe anisotropy of electromagnetic propagation. A controversial recent study claimed a signal of dipole character. Here we test a new and independent data set of 361 points under the null proposal of {\it statistical independence} of linear polarization alignments relative to galaxy axes

Joseph A. Minahan

We compute the quark-monopole potential for ${\cal N}=4$ super Yang-Mills in the large $N$ limit. We find an attractive potential that falls off as 1/L and is manifestly invariant under $g\to 1/g$. The strength of the potential is less than the quark-antiquark and monopole-antimonopole potentials.

James R. Graham, Mark Abrams, C. Bennett, J. Carr

We describe a concept for an imaging spectrograph for a large orbiting observatory such as NASA&#39;s proposed Next Generation Space Telescope (NGST) based on an imaging Fourier transform spectrograph (IFTS). An IFTS has several important advantages which make it an ideal instrument to pursue the scientific objectives of NGST. We review the operation of an I

David Bowser-Chao, Tom D. Imbo, B. Alex King, Eric C. Martell

We consider bound states of heavy leptoquark-antiquark pairs (lepto-mesons) as well as leptoquark-antileptoquark pairs (leptoquarkonium). Unlike the situation for top quarks, leptoquarks (if they exist) may live long enough for these hadrons to form. We study the spectra and decay widths of these states in the context of a nonrelativistic potential model whi

Lajos Diosi

The recently reported relativistic formulation of the well-known non-relativistic quantum state diffusion is seriously mistaken. It predicts, for instance, inconsistent measurement outcomes for the same system when seen by two different inertial observers.

Victor M. Perez-Garcia, H. Michinel, H. Herrero

We obtain analytic solutions to the Gross-Pitaevskii equation with negative scattering length in highly asymmetric traps. We find that in these traps the Bose--Einstein condensates behave like quasiparticles and do not expand when the trapping in one direction is eliminated. The results can be applicable to the control of the motion of Bose--Einstein condens

W. A. Rodrigues, Jayme Vaz, Erasmo Recami, G. Salesi

We start from the spinning electron theory by Barut and Zanghi, which has been recently translated into the Clifford algebra language. We &#34;complete&#34; such a translation, first of all, by expressing in the Clifford formalism a particular Barut-Zanghi (BZ) solution, which refers (at the classical limit) to an internal helical motion with a time-like spe

M. Pavsic, Erasmo Recami, W. A. Rodrigues

The recent literature shows a renewed interest, with various independent approaches, in the classical theories for spin. Considering the possible interest of those results, at least for the electron case, we purpose in this paper to explore their physical and mathematical meaning, by the natural and powerful language of Clifford algebras (which, incidentally

Alejandro Rivero

The complex exponential weighting of Feynman formalism is seen to happen at the classical level. (Finiteness of) Feynman path integral formula is suspected then to appear as a consistency condition for the existence of certain Dirac measures over functional spaces.