November 1998 arXiv papers — page 4

Craig A. Tracy, Harold Widom

This paper is concerned with certain connections between the ensemble of n x n unitary matrices -- specifically the characteristic function of the random variable tr(U) -- and combinatorics -- specifically Ulam's problem concerning the distribution of the length of the longest increasing subsequence in permutation groups -- and the appearance of Painleve

A. Fotopoulos, T. R. Taylor

The strong coupling behavior of finite temperature free energy in N=4 supersymmetric SU(N) Yang-Mills theory has been recently discussed by Gubser, Klebanov and Tseytlin in the context of AdS-SYM correspondence. In this note, we focus on the weak coupling behavior. As a result of a two-loop computation we obtain, in the large N 't Hooft limit, $F(g^2N\to 0)\

Tad Hogg, Carlos Mochon, Wolfgang Polak, Eleanor Rieffel

We present efficient implementations of a number of operations for quantum computers. These include controlled phase adjustments of the amplitudes in a superposition, permutations, approximations of transformations and generalizations of the phase adjustments to block matrix transformations. These operations generalize those used in proposed quantum search a

V. A. Soroka

A linear degenerate odd Poisson bracket (antibracket) realized solely on Grassmann variables is presented. It is revealed that this bracket has at once three nilpotent $Δ$-like differential operators of the first, the second and the third orders with respect to the Grassmann derivatives. It is shown that these $Δ$-like operators together with the Grassmann-o

C. G. Torre, M. Varadarajan

We consider the problem of evolving a quantum field between any two (in general, curved) Cauchy surfaces. Classically, this dynamical evolution is represented by a canonical transformation on the phase space for the field theory. We show that this canonical transformation cannot, in general, be unitarily implemented on the Fock space for free quantum fields

Qaisar Shafi, Zurab Tavartkiladze

We show how a unified description of the various two-flavor neutrino oscillation solutions, allowed by the atmospheric and solar neutrino experiments, are naturally realized within the framework of $ν$MSSM (MSSM augmented with the seesaw mechanism) and beyond, especially grand unified theories. A general mechanism for achieving maximal mixing to resolve the

O. Bertolami, D. F. Mota

Spontaneous breaking of Lorentz invariance compatible with observational limits may realistically take place in the context of string theories, possibly endowing the photon with a mass. In this process the conformal symmetry of the electromagnetic action is broken allowing for the possibility of generating large scale ($\sim Mpc$) magnetic fields within infl

E. Pazy, B. Laikhtman

The transition probability for a one dimensional tunneling electron coupled to acoustical phonons is calculated, with the Feynman path-integral method for zero temperature. We considered a realistic electron phonon interaction (deformation potential, piezoelectric), making use of slowness of the phonon system compared to electron tunneling. We show that the

Johan Bijnens, Joaquim Prades

We discuss the matching between long-distance and short-distance at next-to-leading in $1/N_c$ and show how the scheme-dependence from the two-loop renormalization group running can be treated. We then use this method to study the three $O(p^2)$ terms contributing to non-leptonic kaon decays, namely the usual octet and 27-plet derivative terms as well as the

H. Razmi

Using the Clauser-Horne model of Bell's theorem, the locality condition is examined and it is shown the corresponding formulation is equivalent to a factorization process consisting of three stages. The first stage is introduced based on the conditional probability definition in classical theory of probability and the other two stages are based on previo

P. Gambino, P. A. Grassi, F. Madricardo

We study the renormalization of the fermion mixing matrix in the Standard Model and derive the constraints that must be satisfied to respect gauge invariance to all orders. We demonstrate that the prescription based on the {\it on-shell} renormalization conditions is not consistent with the Ward-Takahashi Identities and leads to gauge dependent physical ampl

Ulrich Heinz

This contains the Proceedings of the 5th International Workshop on Thermal Field Theories and Their Applications (TFT98) which took place on 10-14 August 1998 in Regensburg, Germany. The contents are in html and postscript format. The html files contain clickable links to the postscript files of the papers on the LANL e-print archive. All contributions under

Marcos Marino, Gregory Moore

We consider Donaldson-Witten theory on four-manifolds of the form $X=Y \times {\bf S}^1$ where $Y$ is a compact three-manifold. We show that there are interesting relations between the four-dimensional Donaldson invariants of $X$ and certain topological invariants of $Y$. In particular, we reinterpret a result of Meng-Taubes relating the Seiberg-Witten invar

Tomohiro Hotta, Jun Nishimura, Asato Tsuchiya

We study the large N reduced model of D-dimensional Yang-Mills theory with special attention to dynamical aspects related to the eigenvalues of the N by N matrices, which correspond to the space-time coordinates in the IIB matrix model. We first put an upper bound on the extent of space time by perturbative arguments. We perform a Monte Carlo simulation and

Martin Lüscher

It is shown that U(1) chiral gauge theories with anomaly-free multiplets of Weyl fermions can be put on the lattice without breaking the gauge invariance or violating any other fundamental principle. The Ginsparg-Wilson relation plays a key role in this construction, which is non-perturbative and includes all topological sectors of the theory in finite volum

Uwe Grimm, Rudolf A. Roemer, Gudrun Schliecker

Networks generated from Voronoi tessellations of space are prototypes for topologically disordered systems. In order to assess the effects of random coordination on the statistical properties of energy spectra, we analyze tight-binding models for planar topologically disordered systems. To this end, the networks are generated by a simple topological model co

Mikhail Bilenky, German Rodrigo, Arcadi Santamaria

Next-to-leading order calculation for three jet heavy quark production in e^+e^- collisions, including complete quark mass effects, is reviewed. Its applications at LEP/SLC are also discussed.

Vladimir Lyakhovsky, Mariano A. del Olmo

The properties of the set L of extended jordanian twists are studied. It is shown that the boundaries of L contain twists whose characteristics differ considerably from those of internal points. The extension multipliers of these "peripheric" twists are factorizable. This leads to simplifications in the twisted algebra relations and helps to find the

Klaus Morawetz, Pavel Lipavský, Václav Špička, Nai-Hang Kwong

For a set of realistic nucleon-nucleon potentials we evaluate microscopic parameters of binary collisions: a time duration of the scattering state, a mean distance and a rotation of nucleons during a collision. These parameters enter the kinetic equation as non-instantaneous and non-local corrections of the scattering integral, i.e., they can be experimental

Atsuhiro Kitazawa, Kiyohide Nomura

We study the S=1 quantum spin chains with bilinear, biquadratic, plus bond alternation in the vicinity of the S=1 Takhtajan-Babujian model. Transition line between the Haldane and the dimer phases are determined numerically. To see the crossover behavior from c=3/2 (k=2 SU(2) WZW model) at the Takhtajan-Babujian point to c=1 (k=1 SU(2) WZW model), we calcula

Gabrielle Bonnet, Francois David

We develop a method to obtain the large N renormalization group flows for matrix models of 2 dimensional gravity plus branched polymers. This method gives precise results for the critical points and exponents for one matrix models. We show that it can be generalized to two matrices models and we recover the Ising critical points.

R. Mallik, E. S. Reddy, P. L. Paulose, Subham Mazumdar

We present results of electrical resistivity, magnetoresistance and ac and dc magnetic susceptibility on polycrystalline samples of the type La(0.5)Ca(0.5-x)Ba(x)MnO(3) synthesized under identical heat treatment conditions. The substitution of larger Ba ions for Ca results in a non- monotonic variation of the curie temperature as the system evolves from a ch

Motohico Mulase, Michael Penkava

It is well known that there is a bijective correspondence between metric ribbon graphs and compact Riemann surfaces with meromorphic Strebel differentials. In this article, it is proved that Grothendieck's correspondence between dessins d'enfants and Belyi morphisms is a special case of this correspondence. For a metric ribbon graph with edge length

Nicos Pelavas, Kayll Lake

We examine the possibility that the gravitational contribution to the entropy of a system can be identified with some measure of the Weyl curvature. In this paper we consider homothetically self-similar spacetimes. These are believed to play an important role in describing the asymptotic properties of more general models. By exploiting their symmetry propert

C. C. Steidel, K. L. Adelberger, M. Giavalisco, M. Dickinson

We present initial results of a survey for star-forming galaxies in the redshift range 3.8 < z < 4.5. This sample consists of a photometric catalog of 244 galaxies culled from a total solid angle of 0.23 square degrees to an apparent magnitude of I_{AB}=25.0. Spectroscopic redshifts in the range 3.61 < z < 4.81 have been obtained for 48 of these galaxies; th

H. Razmi

It seems that the problem of finding a suitable position operator for photon has been solved in a recently published work which is based on a new commutation relation between position and momentum operators of massless particles[1]. Although the authors of [1] have presented a classical reasoning in favour of the new commutator,here we are going to find this

Stefan Weigert

Quantum mechanics of a particle in an infinite square well under the influence of a time-dependent electric field is reconsidered. In some gauge, the Hamiltonian depends linearly on the momentum operator which is symmetric but not self-adjoint when defined on a finite interval. In spite of this symmetric part, the Hamiltonian operator is shown to be self-adj

Ralf Kemkemer, Dieter Kling, Dieter Kaufmann, Hans Gruler

In culture migrating and interacting amoeboid cells can form nematic liquid crystal phases. A polar nematic liquid crystal is formed if the interaction has a polar symmetry. One type of white blood cells (granulocytes) form clusters where the cells are oriented towards the center. The core of such an orientational defect (disclination) is either a granulocyt

Arata Hayashigaki

We calculate the spin-averaged $J/ψ$-nucleon scattering length $a_{J/ψ}$ by directly applying QCD sum rule to $J/ψ$-$N$ forward scattering amplitude. Our result $a_{J/ψ} = - 0.10 \pm 0.02$ fm, predicts the possibility of bound states with nuclei, though the force is weaker than that of the light vector mesons ($ρ,ω,ϕ$)-$N$ cases. Up to dimension-4 gluonic op

Klaus Morawetz, Pavel Lipavský, Václav Špička

A kinetic equation which combines the quasiparticle drift of Landau&#39;s equation with a dissipation governed by a nonlocal and noninstantaneous scattering integral in the spirit of Enskog corrections is discussed. Numerical values of the off-shell contribution to the Wigner distribution, of the collision duration and of the collision nonlocality are presen

Z. S. Wang, Amand Faessler, C. Fuchs, T. Waindzoch

Collective flow of Lambda hyperons in heavy ion reactions at SIS energies is investigated. It is found that a $Λ$ mean field constructed on the basis of the quark model leads to a good description of the experimental data of the in-plane transverse flow of $Λ$&#39;s. The attractive mean field can also give rise to an additional &#34;virtual&#34; $Λ$ radial f

K. Saito

We review the quark-meson coupling model, in which the quark degrees of freedom are explicitly involved to describe the properties of not only nuclear matter but also finite nuclei. Then, we present the electric and magnetic form factors for the proton bound in specific orbits for several closed-shell nuclei.

Martin J. Savage

Physics beyond the standard model of electroweak interactions that violates lepton number will, in general, induce operators involving the quark and lepton fields that violate lepton number. I point out that some matrix elements of particular operators are known. In the limit of exact SU(3) flavor symmetry the operator overline{u} gamma_mu (1-gamma_5)d overl

Motohico Mulase

In these lectures three different methods of computing the asymptotic expansion of a Hermitian matrix integral is presented. The first one is a combinatorial method using Feynman diagrams. This leads us to the generating function of the reciprocal of the order of the automorphism group of a tiling of a Riemann surface. The second method is based on the class

Bernard Shiffman, Mikhail Zaidenberg

We construct two classes of singular Kobayashi hyperbolic surfaces in $P^3$. The first consists of generic projections of the cartesian square $V = C \times C$ of a generic genus $g \ge 2$ curve $C$ smoothly embedded in $P^5$. These surfaces have C-hyperbolic normalizations; we give some lower bounds for their degrees and provide an example of degree 32. The

Louis H. Kauffman

This paper is an exposition of heuristics related to Witten&#39;s functional integral, relating it to Vassiliev invariants and to the Kontsevich integrals that can be used to produce Vassiliev invariants of knots and links.In particular, we give a simplified version of the appearance of the Kontsevich integrals in the perturbation expansion of the functional

Paolo Cea, Luigi Tedesco

The spontaneous generation of uniform magnetic condensate in $QED_3$ gives rise to ferromagnetic domain walls at the electroweak phase transition. These ferromagnetic domain walls are caracterized by vanishing effective surface energy density avoiding, thus, the domain wall problem. Moreover we find that the domain walls generate a magnetic field $B \simeq 1

I. Brevik

The Casimir energy for the transverse oscillations of a piecewise uniform closed string is calculated. The string is relativistic in the sense that the velocity of transverse waves is always equal to c. The great adaptibility of this string model with respect to various regularization methods is pointed out. We survey several regularization methods: the cuto

Brian P. Dolan

An analytic form for the crossover of the conductivity tensor between two Hall plateaux, as a function of the external magnetic field, is proposed. The form of the crossover is obtained from the action of a symmetry group, a particular subgroup of the modular group, on the upper-half complex conductivity plane, by assuming that the beta-function describing t

G. Delfino

We use the exact scattering description of the scaling Ashkin-Teller model in two dimensions to compute the two-particle form factors of the relevant operators. These provide an approximation for the correlation functions whose accuracy is tested against exact sum rules.

Daniel Brace, Bogdan Morariu, Bruno Zumino

We investigate T-duality of toroidally compactified Matrix model with arbitrary Ramond-Ramond backgrounds in the framework of noncommutative super Yang-Mills gauge theory.

A. I. Mudrov, K. B. Varnashev

A new approach to summation of divergent field-theoretical series is suggested. It is based on the Borel transformation combined with a conformal mapping and does not imply the knowledge of the exact asymptotic parameters. The method is tested on functions expanded in their asymptotic power series and applied to estimating the ground state energy of simple q

Thomas Schaefer, Frank Wilczek

We review, clarify, and extend the notion of color-flavor locking. We present evidence that for three degenerate flavors the qualitative features of the color-flavor locked state, reliably predicted for high density, match the expected features of hadronic matter at low density. This provides, in particular, a controlled, weak-coupling realization of confine

Andrzej J. Buras, Luca Silvestrini

We analyze rare kaon decays in models in which the dominant new effect is an enhanced $\bar s d Z$ vertex $Z_{ds}$. We point out that in spite of large theoretical uncertainties the CP-violating ratio $ε^\prime/ε$ provides at present the strongest constraint on $\Im Z_{ds}$. Assuming $0 \le ε^\prime/ε\le 2 \cdot 10^{-3}$ and Standard Model values for the CKM

P. Nason

I review recent developements in the theory of heavy flavour production. In particular, I dicuss the next-to-leading resummation of soft gluon effects in heavy flavour hadroproduction, and the next-to-leading resummation of collinear radiation in the production of heavy flavour at large transverse momenta.

A. Sirlin

Developments in the analysis of W and quark propagators in the resonance region, and recent considerations concerning the mass and width of the Higgs boson are reviewed. Particular emphasis is placed on the instability of these fundamental particles, and on related issues of gauge dependence.

B. A. Kniehl

If QCD is renormalized by minimal subtraction (MS), at higher orders, the strong coupling constant alpha_s and the quark masses m_q exhibit discontinuities at the flavour thresholds, which are controlled by so-called decoupling constants, zeta_g and zeta_m, respectively. Adopting the modified MS (MS-bar) scheme, we derive simple formulae which reduce the cal

X. Song

Quark spin and orbital angular momentum in the nucleon are calculated in symmetry-breaking chiral quark model. The results are compared with data and other models.

E. -M. Ilgenfritz, S. V. Molodtsov, M. Müller-Preussker, A. I. Veselov

Finite temperature SU(2) lattice gauge theory is investigated in a 3D cubic box with fixed boundary conditions provided by a discretized, static BPS monopole solution with varying core scale $μ$. Using heating and cooling techniques we establish that for discrete $μ$-values stable classical solutions either of self-dual or of pure magnetic type exist inside

Alan J. Weinstein

I very briefly review the highlights of the fifth workshop on the physics of the tau lepton and its neutrino. There has been much progress in many sub-fields, which I touch upon in this review: the couplings of the tau to the $Z^0$ and $W^\pm$; the leptonic branching fractions, lifetime, and tests of universality; the Lorentz structure of tau decays; searche

Alan J. Weinstein

We present measurements of the tau Michel Parameters made by the CLEO experiment. Three different analyses are performed: a spin-independent lepton spectrum analysis and a second spin-dependent analysis using $\ell^\pm$ \vs\ $π^\mpπ^0$ events, and a third spin-dependent analysis using $π^+$ \vs\ $π^-$ events. the results are used to derive limits on the gene

J. Bartelt

Using a sample of 3.3 million B-meson decays collected with the CLEO detector at the Cornell Electron Storage Ring, we have studied $B^- \to D^0 \ellν$ and $\bar{B}^0 \to D^+ \ellν$ decays, where $\ell$ can be either an electron or muon. We distinguish $B \to D \ellν$ from other B semileptonic decays by examining the net momentum and energy of the particles

M. Pepe-Altarelli

A summary of the W-boson properties measured by the four LEP collaborations is presented here. These properties are updated to take into account the most recent results presented at the ICHEP98 conference.

J. Demaret, L. Querella, C. Scheen

We develop a Hamiltonian formulation of the Bianchi type I space-time in conformal gravity, i.e. the theory described by a Lagrangian that is defined by the contracted quadratic product of the Weyl tensor, in a four-dimensional space-time. We derive the explicit forms of the super-Hamiltonian and of the constraint expressing the conformal invariance of the t

Alessandro Chessa, Alessandro Vespignani, Stefano Zapperi

We present large scale simulations of a stochastic sandpile model in two dimensions. We use moments analysis to evaluate critical exponents and finite size scaling method to consistently test the obtained results. The general picture resulting from our analysis allows us to characterize the large scale behavior of the present model with great accuracy.

C. Bergemann, S. R. Julian, A. P. Mackenzie, A. W. Tyler

Sr2RuO4 is the only known layered perovskite oxide superconductor without copper; there is strong evidence for an unconventional (&#34;p-wave&#34;) pairing mechanism, and it has recently been shown to possess a cylindrical, &#34;quasi-two-dimensional&#34; Fermi surface. Using Sr2RuO4 as a test case for the detection of quantum oscillations with piezoresistiv

D. Sanchez-Portal, E. Artacho, J. M. Soler, A. Rubio

A study based on ab initio calculations is presented on the estructural, elastic, and vibrational properties of single-wall carbon nanotubes with different radii and chiralities. We use SIESTA, an implementation of pseudopotential-density-functional theory which allows calculations on systems with a large number of atoms per cell. Different quantities like b

Adriana G. Dickman, Bartira C. S. Grandi, Wagner Figueiredo, Ronald Dickman

We derive a pair approximation (PA) for the NO+CO model with instantaneous reactions. For both the triangular and square lattices, the PA, derived here using a simpler approach, yields a phase diagram with an active state for CO-fractions y in the interval y_1 < y < y_2, with a continuous (discontinuous) phase transition to a poisoned state at y_1 (y_2). Thi

Michael Schreiber, Uwe Grimm, Rudolf A. Roemer, Jian-Xin Zhong

We consider a tight-binding Hamiltonian defined on the quasiperiodic Ammann-Beenker tiling. Although the density of states (DOS) is rather spiky, the integrated DOS is quite smooth and can be used to perform spectral unfolding. The effect of unfolding on the integrated level-spacing distribution is investigated for various parts of the spectrum which show di

M. A. Odnoblyudov, I. N. Yassievich, M. S. Kagan, Yu. M. Galperin

We present a theoretical prediction of a new mechanism for carrier population inversion in semiconductors under an applied electric field. The mechanism is originated from a coherent capture-emission type inelastic scattering of resonant states. We support our theory with concrete calculations for shallow acceptor resonant states in strained p-Ge where a las

A. Cuccoli, A. Fubini, A. Rossi, V. Tognetti

We consider quantum nonlinear systems with dissipation described within the Caldeira-Leggett model, i.e., by a nonlocal action in the path integral for the density matrix. Approximate classical-like formulas are derived in order to evaluate thermal averages of observables: the cases of linear and nonlinear dissipation are considered, and the framework is ext

S. Schafroth, J. J. Rodríguez-Núñez

We evaluate the one-particle and double-occupied Green functions for the Hubbard model at half-filling using the moment approach of Nolting. Our starting point is a self-energy, $Σ(\vec{k},ω)$, which has a single pole, $Ω(\vec{k})$, with {\it spectral} weight, $α(\vec{k})$, and quasi-particle lifetime, $γ(\vec{k})$. In our approach, $Σ(\vec{k},ω)$ becomes th

R. A. Broglia, G. Tiana, H. E. Roman

Making use of a simplified model for protein folding, it can be shown that conformations which are particularly stable when their energy is minimized with respect to amino acid sequence (in the sense that they display a large energy gap to the lowest structrally dissimilar conformation), aside from leading to fast folding, are highly designable (in the sense

Kicheon Kang

We study the coherent transport in multi-terminal mesoscopic Aharonov-Bohm ring with a quantum dot embedded in an arm. Employing the Friedel sum rule for the effective single-particle levels in the quantum dot, we explain some anomalous features which have been observed in the experiment. We attribute these anomalies to the result of nontrivial quantum inter

Prabhat K Thakur, Parthapratim Biswas

We present here a detailed multifractal scaling study for the electronic transmission resonances with the system size for an infinitely large one dimensional perfect and imperfect quasiperiodic system represented by a sequence of $δ$-function potentials. The electronic transmission resonances in the energy minibands manifest more and more fragmented nature o

J. C. Campuzano, H. Ding, H. Fretwell, J. Mesot

In contrast with the recent photoemission observations by Shen et al. of anomalous temperature-induced momentum-dependent spectral weight transfer in Bi_2Sr_2CaCu_2O_{8+delta}, we find that in the same material, in spite of the unusual spectral lineshape change between superconducting and normal states, the integrated spectral weight displays minimum variati

J. E. Hirsch

In the band theory of ferromagnetism there is a relative shift in the position of majority and minority spin bands due to the self-consistent field due to opposite spin electrons. In the simplest realization, the Stoner model, the majority and minority spin bands are rigidly shifted with respect to each other. Here we consider models at the opposite extreme,

Tin-Lun Ho, Gordon Baym

Paper temporarily withdrawn for remodeling

Leonid P. Pryadko, Assa Auerbach

The longstanding problem of the Hall resistivity rho(x,y) in the Hall insulator phase is addressed using four-lead Chalker-Coddington networks. Electron interaction effects are introduced via a finite dephasing length. In the quantum coherent regime, we find that rho(x,y) scales with the longitudinal resistivity rho(x,x), and they both diverge exponentially

David Daems, Siegfried Grossmann, Victor S. L&#39;vov, Itamar Procaccia

It was shown recently that the anomalous scaling of simultaneous correlation functions in turbulence is intimately related to the breaking of temporal scale invariance, which is equivalent to the appearance of infinitely many times scales in the time dependence of time-correlation functions. In this paper we derive a continued fraction representation of turb

R. Rebolo, M. R. Zapatero Osorio, S. Madruga, V. J. S. Bejar

A substellar-mass object in orbit at about 300 astronomical units (AU) from the young low-mass star G196-3 was detected by direct imaging. Optical and infrared photometry and low- and intermediate-resolution spectroscopy of the faint companion, hereafter referred to as G196-3B, confirms its cool atmosphere and allows its mass to be estimated at 25^{+15}_{-10

Ramesh Narayan, John Raymond

We present model X-ray spectra of accreting black holes with advection-dominated accretion flows, paying attention to thermal emission lines from the hot plasma. We show that the Advanced X-ray Astrophysical Facility (AXAF) might be able to observe lines from X-ray binaries such as V404 Cyg in quiescence, the Galactic Center black hole Sagittarius A*, and th

K. Hurley, C. Kouveliotou, P. Woods, T. Cline

In 1998 May, the soft gamma repeater SGR1900+14 emerged from several years of quiescence and emitted a series of intense bursts, one with a time history unlike any previously observed from this source. Triangulation using Ulysses, BATSE, and KONUS data give a 1.6 square arcminute error box near the galactic supernova remnant G42.8+0.6. This error box contain

Rien van de Weygaert, Yehuda Hoffman

Several studies have indicated that the local cosmic velocity field is rather cold, in particular in the regions outside the massive, virialized clusters of galaxies. If our local cosmic environment is taken to be a representative volume of the Universe, the repercussion of this finding is that either we live in a low-$Ω$ Universe and/or that the galaxy dist

D. Thomas

The relevance of galaxies of different luminosity and mass for the chemical enrichment of the intracluster medium (ICM) is analysed. For this purpose, I adopt the composite luminosity function of cluster galaxies from Trentham (1998), which exhibits a significant rise at the very faint end. The model - adopting a universal Salpeter IMF - is calibrated on rep

D. Palle

We study cosmological density fluctuations within a covariant and gauge-invariant fluid-flow approach for a perfect fluid in the Einstein-Cartan gravity and derive the corresponding Raychaudhuri type of inhomogeneous coupled differential evolution equations of the second order. It appears that the quantum fluctuations of spin trigger primordial density inhom

Alessandro Capetti, Annalisa Celotti

Hubble Space Telescope (HST) observations provide a novel way of testing unified models for FR I radio sources and BL Lac objects. The detection of extended dust discs in some radio galaxies provides information on their jet orientation. Given this, the strength of the compact nuclear sources of FR I and BL Lacs can be compared with model predictions. As a p

Dong-Woo Kim, Martin Elvis

We have performed a successful targetted search for a population of red radio-quiet, and probably absorbed, quasars. Radio-quiet, optically-red ROSAT PSPC X-ray sources brighter than 10^{-13} erg cm^{-2} s^{-1} were searched for red (O-E > 2.0, O < 20) counterparts in the APM catalog of Palomar Sky Survey objects. Of 45 objects for which we obtained adequate

Andrzej M. Soltan, Jozef Juchniewicz

Contribution to the gamma-ray background (GRB) by galaxies bright in the far-IR (FIR) is discussed. Using observational correlations between the FIR and synchrotron emission in radio wavelengths, it is shown that the concentration of cosmic ray electrons in FIR luminous galaxies is substantially higher than in the general population of galaxies. Microwave ba

Peter G. Jonker, Michiel van der Klis, Rudy Wijnands

We have discovered a ~1 Hz quasi-periodic oscillation (QPO) in the persistent-emission, the dips, and the type I X-ray bursts of the low-mass X-ray binary 4U 1323-62. The rms amplitude of the QPO is approximately 9%, only weakly depending on photon energy. The amplitude is consistent with being constant throughout the persistent-emission, the dips and the bu

Andi Kronawitter, Ortwin E. Gerhard, R. P. Saglia, Ralf Bender

We describe a non-parametric method for determining both the anisotropy and mass profiles of elliptical galaxies from velocity dispersions and velocity profile shapes along the line of sight. In this way, mass-to-light ratios out to 2-3 effective radii can be derived from stellar absorption line spectroscopy. We discuss two illustrative cases, NGC 1399 and N

Abhas Mitra

We derive here the expression for the accretion luminosity, $L(\infty)$, as seen by a distant inertial observer $S_\infty$, for the case of spherical accretion onto a static compact object having a surface gravitational red-shift $z_x$. It is found that the ``efficiency&#39;&#39; for conversion of mass energy into accretion energy is given by $ε= z_x/(1+z_x)

J. H. Huang, Y. Chen, L. Ji, Q. S. Gu

We report our preliminary results on the role of starbursts in LINERs by use of WR galaxies as a tool. The essence of this approach lies in the different FIR-radio relation of WR galaxies from the pure AGN&#39;s.

C. C. Steidel

This paper reviews the current status of measurements of galaxy clustering at high redshifts (z > 0.3). The focus is on the inherent limitations in the observation and interpretation of the ``evolution of clustering&#39;&#39;. It is likely that results from the first attempts to characterize galaxy clustering beyond the ``local&#39;&#39; universe have been s

M. Toscano, J. S. Sandhu, M. Bailes, R. N. Manchester

We present improved timing parameters for 13 millisecond pulsars (MSPs) including 9 new proper motion measurements. These new proper motions bring to 23 the number of MSPs with measured transverse velocities. In light of these new results we present and compare the kinematic properties of MSPs with those of ordinary pulsars. The mean transverse velocity of M

Mareki Honma

Caustic crossing microlensing events provide us a unique opportunity to measure the relative proper motion of the lens to the source, and so those caused by binary MACHOs are of great importance for understanding the structure of the Galactic halo and the nature of MACHOs. The microlensing event 98-SMC-01, occurred in June 1998, is the first event for which

Zoltan Haiman, Marco Spaans

We present models for dusty high-redshift Lyman alpha emitting galaxies by combining the Press-Schechter formalism with a treatment of inhomogeneous dust distribution inside galaxies. These models reproduce the surface density of emitters inferred from recent observations, and also agree with previous non-detections. Although a detailed determination of the

Zoltan Haiman, Avi Loeb

Empirical studies of the first generation of stars and quasars in the Universe will likely become feasible over the next decade. The Next Generation Space Telescope will provide direct imaging and photometry of sub-galactic objects at redshifts above z=10, while microwave anisotropy experiments, such as MAP or Planck, will set constraints on the ionization h

Wolfgang Rhode, Torsten A. Ensslin, Peter L. Biermann

EGRET data on the Gamma ray emission from the inner Galaxy have shown a rather flat spectrum, extending to about 50 GeV. It is usually assumed that these gamma-rays arise from the interactions of cosmic ray nuclei with ambient matter. Cosmic Ray particles have been observed up to 3 10^20 eV, with many arguments suggesting, that up to about 3 10^18 eV they ar

Debbie Leung, Lieven Vandersypen, Xinlan Zhou, Mark Sherwood

Using nuclear magnetic resonance techniques, we experimentally investigated the effects of applying a two bit phase error detection code to preserve quantum information in nuclear spin systems. Input states were stored with and without coding, and the resulting output states were compared with the originals and with each other. The theoretically expected res

Sabino José Ferreira, Alan D. Sokal

We study the antiferromagnetic q-state Potts model on the square lattice for q=3 and q=4, using the Wang-Swendsen-Kotecky (WSK) Monte Carlo algorithm and a powerful finite-size-scaling extrapolation method. For q=3 we obtain good control up to correlation length $\xi \sim 5000$; the data are consistent with $\xi(\beta) = A e^{2\beta} \beta^p (1 + a_1 e^{-\be

Shoichi Sasaki, Osamu Miyamura

We show that the hypothesis of abelian dominance allows QCD-monopoles to preserve the topological feature of the QCD vacuum within SU(2) lattice gauge theory. An analytical study is made to find the relationship between the topological charge and QCD-monopoles in the lattice formulation. The topological charge is explicitly represented in terms of the monopo

Yakov Itin

We have shown recently that the gravity field phenomena can be described by a traceless part of the wave-type field equation. This is an essentially non-Einsteinian gravity model. It has an exact spherically-symmetric static solution, that yields to the Yilmaz-Rosen metric. This metric is very close to the Schwarzchild metric. The wave-type field equation ca

A. B. Peck, G. B. Taylor, J. E. Conway

We present results of VLA and VLBA observations of the 1.420 GHz neutral hydrogen absorption associated with the Compact Symmetric Object 1946+708 (z=0.101). We find significant structure in the gas on parsec scales. The peak column density in the HI (N_HI~2.2x10^23 cm^-2 (T_s/8000K)) occurs toward the center of activity of the source, as does the highest ve

Gabriele Ferretti, Dario Martelli

We investigate Polyakov&#39;s proposal of constructing Yang-Mills theories by using non critical type 0 strings. We break conformal invariance by putting the system at finite temperature and find that the entropy of the cosmological solutions for these theories matches that of a gas of weakly interacting Yang-Mills bosons, up to a numerical constant. The com

Johanna Erdmenger, Christian Rupp

Superconformal Ward identities for N=1 supersymmetric quantum field theories in four dimensions are convenienty obtained in the superfield formalism by combining diffeomorphisms and Weyl transformations on curved superspace. Using this approach we study the superconformal transformation properties of Green functions with one or more insertions of the supercu

Martin G. Harris, John F. Wheater

We calculate the Hausdorff dimension, $d_H$, and the correlation function exponent, $η$, for polymerized two dimensional quantum gravity models. If the non-polymerized model has correlation function exponent $η_0 >3$ then $d_H=γ^{-1}$ where $γ$ is the susceptibility exponent. This suggests that these models may be in the same universality class as certain no

Wolfgang Lucha, F. F. Schoberl

Using Mathematica 3.0, the Schroedinger equation for bound states is solved. The method of solution is based on a numerical integration procedure together with convexity arguments and the nodal theorem for wave functions. The interaction potential has to be spherically symmetric. The solving procedure is simply defined as some Mathematica function. The outpu

T. D. Palev, N. I. Stoilova

A description of the quantum superalgebra $U_q[sl(n+1|m)]$ and in particular of the special linear superalgebra $sl(n+1|m)$ via creation and annihilation generators (CAGs) is given. It provides an alternative to the canonical description of $U_q[sl(n+1|m)]$ in terms of Chevalley generators. A conjecture that the Fock representations of the CAGs provide micro

Erik Luijten

Accurate numerical results are presented for the three-dimensional equivalent-neighbor model on a cubic lattice, for twelve different interaction ranges (coordination number between 18 and 250). These results allow the determination of the range dependences of the critical temperature and various critical amplitudes, which are compared to renormalization-gro