November 1999 arXiv papers — page 12

Grigori Litvinov, Viktor Maslov, Andrei Sobolevskii

A brief introduction into Idempotent Mathematics and an idempotent version of Interval Analysis are presented. Some applications are discussed.

C. Dembowski, H. -D. Graef, A. Heine, R. Hofferbert

We report on first experimental signatures for chaos-assisted tunneling in a two-dimensional annular billiard. Measurements of microwave spectra from a superconducting cavity with high frequency resolution are combined with electromagnetic field distributions experimentally determined from a normal conducting twin cavity with high spatial resolution to resol

Jounghun Lee, Ue-Li Pen

We discuss the origin of galactic angular momentum, and the statistics of the present day spin distribution. It is expected that the galaxy spin axes are correlated with the intermediate principal axis of the gravitational shear tensor. This allows one to reconstruct the shear field and thereby the full gravitational potential from the observed galaxy spin f

Frederick Green, Mukunda P Das

Coulomb screening, together with degeneracy, is characteristic of the metallic electron gas. While there is little trace of its effects in transport and noise in the bulk, at mesoscopic scales the electronic fluctuations start to show appreciable Coulomb correlations. Within a strictly standard Boltzmann and Fermi-liquid framework, we analyze these phenomena

Jose D. Edelstein, Marta Gomez-Reino, Marcos Marino, Javier Mas

We embed the Seiberg-Witten solution for the low energy dynamics of N=2 super Yang-Mills theory with an even number of massive hypermultiplets into the Whitham hierarchy. Expressions for the first and second derivatives of the prepotential in terms of the Riemann theta function are provided which extend previous results obtained by Gorsky, Marshakov, Mironov

Yunbo Zeng, Wen-Xiu Ma

Binary constrained flows of soliton equations admitting $2\times 2$ Lax matrices have 2N degrees of freedom, which is twice as many as degrees of freedom in the case of mono-constrained flows. For their separation of variables only N pairs of canonical separated variables can be introduced via their Lax matrices by using the normal method. A new method to in

L. Accardi, S. V. Kozyrev

The stochastic limit for the system of spins interacting with a boson field is investigated. In the finite volume an application of the stochastic golden rule shows that in the limit the dynamics of a quantum system is described by a quantum white noise equation that after taking of normal order is equivalent to quantum stochastic differential equation (QSDE

Stuart Mirell, Daniel Mirell

A new method for high efficiency interaction-free measurement is presented. Selective transmission of multiple beam interference is used to generate a continuous wave target beam with an irradiance level ~1% that of a reference beam. When the target beam is unobstructed by a potentially interposed object, the resultant measured interference visibility of 0.8

C. Silva, I. R. Pimentel, A. Andrade, J. P. Foreid

Purpose: The understanding of brain activity, and in particular events such as epileptic seizures, lies on the characterisation of the dynamics of the neural networks. The theory of non-linear dynamics provides signal analysis techniques which may give new information on the behaviour of such networks. Methods: We calculated correlation dimension maps for 19

G. Getz, E. Levine, E. Domany, M. Q. Zhang

High-density DNA arrays, used to monitor gene expression at a genomic scale, have produced vast amounts of information which require the development of efficient computational methods to analyze them. The important first step is to extract the fundamental patterns of gene expression inherent in the data. This paper describes the application of a novel cluste

Brian K. Davis

DNA dependent RNA polymerase core subunits abb' conserved residues at frequencies most closely matched with codons at stage 10.4-11.1 in code evolution. An excess of acidic residues (stage 2 additions) lowered this estimate, but not by more than 2.3 stages. With 1 tryptophan (stage 14 addition) in 529 conserved residues, abb' significantly under-repr

Claus O. Wilke, Christopher Ronnewinkel, Thomas Martinetz

The quasispecies theory is studied for dynamic replication landscapes. A meaningful asymptotic quasispecies is defined for periodic time dependencies. The quasispecies' composition is constantly changing over the oscillation period. The error threshold moves towards the position of the time averaged landscape for high oscillation frequencies and follows

S. Jeschonnek, J. W. Van Orden

In a series of recent publications, a new approach to the non-relativistic reduction of the electromagnetic current operator in calculations of electro-nuclear reactions has been introduced. In one of these papers, the conjecture that at energies of a few GeV, the bulk of the relativistic effects comes from the current and not from the nuclear dynamics was m

S. Mizutori, J. Dobaczewski, G. A. Lalazissis, W. Nazarewicz

Nuclei with large neutron-to-proton ratios have neutron skins, which manifest themselves in an excess of neutrons at distances greater than the radius of the proton distribution. In addition, some drip-line nuclei develop very extended halo structures. The neutron halo is a threshold effect; it appears when the valence neutrons occupy weakly bound orbits. In

R. Barbier, M. Kibler

A rotor system, having the symmetry afforded by the two-parameter quantum algebra Uqp(u(2)), is investigated in this communication. This system is useful in rotational spectroscopy of molecules and nuclei. In particular, it is shown to lead to a model (viz., the qp-rotor model) for describing (via an energy formula and a qp-deformation of E2 reduced transiti

P. Amore, R. Cenni, P. Saracco

The presence of a resonant structure corresponding to the $Δ$ excitation in the longitudinal response to an e.m. probe is investigated. It is shown that many-body effects could significantly increase the relativistic contribution suggested by M.Ericson and coworkers

K. Sümmerer, B. Blank

New experimental data obtained mainly at the GSI/FRS facility allow to modify the empirical parametrization of fragmentation cross sections, EPAX. It will be shown that minor modifications of the parameters lead to a much better reproduction of measured cross sections. The most significant changes refer to the description of fragmentation yields close to the

Alexander Strohmaier

We prove the Reeh-Schlieder property for the ground- and KMS-states states of the massive Dirac Quantum field on a static globally hyperbolic 4 dimensional spacetime.

V. I. Inozemtsev

The eigenvectors of the Hamiltonian ${\cal H}_{N}$ of $N$-sites quantum spin chains with elliptic exchange are connected with the double Bloch meromorphic solutions of the quantum continuous elliptic Calogero-Moser problem. This fact allows one to find the eigenvectors via the solutions to the system of highly transcendental equations of Bethe-ansatz type wh

Hansjorg Geiges, Charles B. Thomas

A free action of a finite group on an odd-dimensional sphere is said to be almost linear if the action restricted to each cyclic or 2-hyperelementary subgroup is conjugate to a free linear action. We begin this survey paper by reviewing the status of almost linear actions on the 3-sphere. We then discuss almost linear actions on higher-dimensional spheres, p

David Gauld

In this paper we give a brief introduction to criteria for metrisability of a manifold and to some aspects of non-metrisable manifolds. Bias towards work currently being done by the author and his colleagues at the University of Auckland will be very evident.

S. K. Donaldson

The goal of this paper is to give a new proof of a theorem of Meng and Taubes that identifies the Seiberg-Witten invariants of 3-manifolds with Milnor torsion. The point of view here will be that of topological quantum field theory. In particular, we relate the Seiberg-Witten equations on a 3-manifold with the Abelian vortex equations on a Riemann surface. T

Steven A. Bleiler, Craig D. Hodgson, Jeffrey R. Weeks

This paper concerns the Dehn surgery construction, especially those Dehn surgeries leaving the manifold unchanged. In particular, we describe an oriented 1-cusped hyperbolic 3-manifold X with a pair of slopes r_1, r_2 such that the Dehn filled manifolds X(r_1), X(r_2) are oppositely oriented copies of the lens space L(49,18), and there is no homeomorphism h

I. K. Babenko, I. A. Taimanov

The paper is devoted to study of Massey products in symplectic manifolds. Theory of generalized and classical Massey products and a general construction of symplectic manifolds with nontrivial Massey products of arbitrary large order are exposed. The construction uses the symplectic blow-up and is based on the author results, which describe conditions under

Genkai Zhang

We realize the relative discrete series of a weighted $L^2$-space on a bounded symmetric doamin as kernels of invariant Cauchy-Riemann operator, and thus as the spaces of nearly holomorphic functions.

M. Havlicek, A. Klimyk, S. Posta

The aim of this paper is to give a set of central elements of the algebras $U'_q({\rm so}_m)$ and $U_q({\rm iso}_m)$ when q is a root of unity. They are surprisingly arise from a single polynomial Casimir element of the algebra $U'_q({\rm so}_3)$. It is conjectured that the Casimir elements of these algebras under any values of q (not only for q a ro

N. Z. Iorgov, A. U. Klimyk

The nonstandard q-deformation $U'_q({\rm so}_n)$ of the universal enveloping algebra $U({\rm so}_n)$ has irreducible finite dimensional representations which are a q-deformation of the well-known irreducible finite dimensional representations of $U({\rm so}_n)$. But $U'_q({\rm so}_n)$ also has irreducible finite dimensional representations which have

Alex Chigogidze, M. M. Zarichnyi

We give a topological characterization of the n-dimensional pseudo-boundary of the (2n+1)-dimensional Euclidean space.

E. Andruchow, A. Varela

Let M be a von Neumann algebra, f a faithful normal state and denote by M^f the fixed point algebra of the modular group of f. Let U_M and U_{M^f} be the unitary groups of M and M^f. In this paper we study the quotient U_M/U_{M^f} endowed with two natural topologies: the one induced by the usual norm of M (called here usual topology), and the one induced by

M. V. Movshev

We introduce a formalism which allows us to formulate a version of Fukaya category in presence of curves of higher genus.

Ignasi Mundet i Riera

Let $X$ be a compact Kaehler manifold and $E\to X$ a principal $K$ bundle, where $K$ is a compact connected Lie group. Let ${\cal A}^{1,1}$ be the set of connections on $E$ whose curvature lies in $Ω^{1,1}(E\times_{Ad} {\frak k})$, where ${\frak k}$ is the Lie algebra of $K$. Endow $\frak k$ with a nondegenerate biinvariant bilinear pairing. This allows to i

Alexander Polishchuk

We construct an $A_{\infty}$-structure on the Ext-groups of hermitian holomorphic vector bundles on a compact complex manifold. We propose a generalization of the homological mirror conjecture due to Kontsevich. Namely, we conjecture that for mirror dual Calabi-Yau manifolds $M$ and $X$ there exists an $A_{\infty}$-functor from Fukaya's symplectic $A_{\i

Ronald Fintushel, Ronald J. Stern

The goal of this paper is to demonstrate that, at least for nonsimply connected 4-manifolds, the Seiberg-Witten invariant alone does not determine diffeomorphism type within the same homeomorphism type.

C. Fronsdal, A. Galindo

We consider the free ${\bf C}$-algebra ${\cal B}_q$ with $N$ generators $\{ξ_i\}_{i = 1,...,N}$, together with a set of $N$ differential operators $\{\partial_i\}_{i = 1,...,N}$ that act as twisted derivations on ${\cal B}_q$ according to the rule $\partial_iξ_j = δ_{ij} + q_{ij}ξ_j\partial_i$; that is, $\forall x \in {\cal B}_q, \partial_i(ξ_jx) = δ_{ij}x +

Michael H. Freedman

We give the first example of systolic freedom over torsion coefficients. The phenomenon is a bit unexpected (contrary to a conjecture of Gromov's) and more delicate than systolic freedom over the integers.

A. Kehagias

The possibility of neutral, brane-like solutions in a higher dimensional setting is discussed. In particular, we describe a supersymmetric solution in six dimensions which can be interpreted as a "three-brane" with a non-compact transverse space of finite volume. The construction can be generalized to n+4-dimensions and the result is a n+3-brane comp

Lorenzo Leal

We consider the Non-Abelian Chern-Simons term coupled to external particles, in a gauge and diffeomorphism invariant form. The classical equations of motion are perturbativelly studied, and the on-shell action is shown to produce knot-invariants associated with the sources. The first contributions are explicitly calculated, and the corresponding knot-invaria

Peter C. Stichel

We develop in a systematic fashion the idea of gauging 1d-space translations with fixed Newtonian time for nonrelativistic matter (particles and fields). By starting with a nonrelativistic free theory we obtain its minimal gauge invariant extension by introducing two gauge fields with a Maxwellian self interaction. We fix the gauge so that the residual symme

J. Rant, M. Schweda, H. Zerrouki

We show the existence of a renormalizable local supersymmetry for the gauge fixed action of the four dimensional antisymmetric tensor field model in a curved background quantized in a generalized axial gauge. By using the technique of the algebraic renormalization procedure, we prove the ultraviolet finiteness of the model to all orders of perturbation theor

B. Ponsot, J. Teschner

The purpose of this short note is to announce results that amount to a verification of the bootstrap for Liouville theory in the generic case under certain assumptions concerning existence and properties of fusion transformations. Under these assumptions one may characterize the fusion and braiding coefficients as solutions of a system of functional equation

B. B. Deo

A string in four dimensions is constructed by supplementing it with forty four Majorana fermions. The central charge is 26. The fermions are grouped in such a way that the resulting action is supersymmetric. The super-Virasoro algebra is constructed and closed by the use of Jacobi identity. The tachyonic ground state decouples from the physical states. GSO p

R. N. Mohapatra, A. Pérez-Lorenzana, C. A. de S. Pires

We present a gauge model for the bimaximal mixing pattern among the neutrinos that explains both the atmospheric and solar neutrino data via large angle vacuum oscillation among the three known neutrinos. The model does not include righthanded neutrinos but additional Higgs triplets which acquire naturally small vev's due to the type II seesaw mechanism.

Ralph Engel, T. K. Gaisser, Todor Stanev

Differences among calculations of the atmospheric neutrino beam can be traced in large part to differences in the representation of pion production by protons interacting with nuclei in the atmosphere. In this paper we review the existing data with the goal of determining the regions of phase space in which new measurements could help to improve the input to

Mrinal Dasgupta

We estimate the power corrections (infrared renormalon contributions) to the coefficient functions for the differential Drell-Yan cross-section $d^2\sigma/dQ^2dy$, where $Q^2$ is the mass squared and $y$ the rapidity of the produced lepton pair. We employ the dispersive method based on the analysis of one-loop Feynman graphs containing a massive gluon.

Matthias Jamin

The present theoretical status of the parameter for direct CP violation epsilon'/epsilon in the Standard Model is reviewed and compared with most recent experimental measurements of the same quantity. After collecting the basic expressions for epsilon'/epsilon, the situation of hadronic matrix element calculations is summarised. The matrix elements c

S. Fajfer, S. Prelovsek, P. Singer

We propose the $B_c\to B_u^*γ$ decay as the most suitable probe for the flavour changing neutral transition $c\to uγ$. We estimate the short and long distance contributions to this decay within the standard model and we find them to be comparable; this is in contrast to radiative decays of $D$ mesons, that are completely dominated by the long distance contri

Robert J. Oakes, Jin Min Yang, Bing-Lin Young

The combined LEP/SLD data on the b\bar b forward-backward asymmetry from the Z-pole measurements may imply the presence of new physics in the $Zb\bar b$ couplings. In general, the effect of new physics can be parameterized by $SU_C(3)\times SU_L(2)\times U_Y(1)$ invariant higher dimensional operators. By fitting the recently announced LEP/SLD data on A_b and

Deirdre Black, Amir H. Fariborz, Joseph Schechter

We review how a certain effective chiral Lagrangian approach to pi pi scattering, pi K scattering and eta-prime decay to eta pi pi provides evidence for the existence of light scalars sigma(550) and kappa(900) as well as describing the f0(980) and the a0(980). An attempt to fit these into a nonet suggests that their structure is closer to a dual quark-dual a

Nima Arkani-Hamed, Savas Dimopoulos, Gia Dvali, Nemanja Kaloper

We propose that our world is a brane folded many times inside the sub-millimeter extra dimensions. The folding produces many connected parallel branes or folds with identical microphysics - a Manyfold. Nearby matter on other folds can be detected gravitationally as dark matter since the light it emits takes a long time to reach us traveling around the fold.

S. Kretzer

In this note we formulate and investigate theoretical uncertainties for high Q^2 deep inelastic heavy quark (charm, etc.) production rates which arise within collinear resummation techniques from variations of the a priori unknown charm input scale Q_0 of O(alpha_s) variable flavour number schemes. We show that Q_0 variations constitute a source of considera

Hyun-Chul Kim, Michal Praszalowicz, Klaus Goeke

%auto-ignore The paper has been withdrawn by authors. The completely revised version can be found under the following preprint-no: hep-ph/9910282.

Alexei Safonov

Presented are the most recent jet fragmentation results from CDF: inclusive distributions of charged particle momenta and their kT in jets; average track multiplicities, as well as angular distributions of multiplicity flow, for a wide range of jet energies with ET from 40 to 300 GeV. The results are compared with Monte-Carlo and, when possible, analytical c

ALEPH Collaboration

Data taken with the ALEPH detector at LEP1 have been used to search for gamma gamma production of the glueball candidates f0(1500) and fJ(1710) via their decay to pi+pi-. No signal is observed and upper limits to the product of gamma gamma width and pi+pi- branching ratio of the f0(1500) and the fJ(1710) have been measured to be Gamma_(gamma gamma -> f0(1500

Victor Varela

We discuss new Majumdar-Papapetrou solutions for the 3+1 Einstein-Maxwell equations, with charged dust acting as the external source of the fields. The solutions satisfy non-linear potential equations which are related to well-known wave equations of 1+1 soliton physics. Although the matter distributions are not localised, they present central structures whi

M. Alimohammadi, A. shariati

In the context of the Einstein-Cartan-Dirac model, where the torsion of the space-time couples to the axial currents of the fermions, we study the effects of this quantum-gravitational interaction on a massless neutrino beam crossing through a medium with high number density of fermions at rest. We calculate the reflection amplitude and show that a specific

Hitoshi Kitada

The a priori time in conventional quantum mechanics is shown to contradict the uncertainty principle. A possible solution is given.

Hitoshi Kitada

A possible solution for the problem of non-existence of universal time is given by utilizing Goedel's incompleteness theorem.

Michael J. O'Donnell

In his Discourse on the Method of Rightly Conducting the Reason, and Seeking Truth in the Sciences, Rene Descartes sought ``clear and certain knowledge of all that is useful in life.'' Almost three centuries later, in ``The foundations of mathematics,'' David Hilbert tried to ``recast mathematical definitions and inferences in such a way that

Alejandro D. Sanchez

We analyze a trapping reaction with a single penetrable trap, in a one dimensional lattice, where both species (particles and trap) are mobile and have a drift velocity. We obtain the density as seen from a reference system attached to the trap and from the laboratory frame. In addition we study the nearest neighbor distance to the trap. We exploit a stochas

J. Hammann, E. Vincent, V. Dupuis, M. Alba

Aging phenomena have been studied in very different materials like polymers, supercooled liquids or disordered orientational crystals. We recall here the main features of aging in spin glasses, and use this example of magnetic systems as a guideline for the description of the others. A particular attention is put on the sensitivity of aging to the cooling ra

S. Curnoe, K. A. Kikoin

SmB6 exhibits intermediate valence in the ground state and unusual behaviour at low temperatures. The resistivity and the Hall effect cannot be explained either by conventional sf-hybridization or by hopping transport in an impurity band. At least three different energy scales determine three temperature regimes of electron transport in this system. We consi

Ziqiang Wang

We study the stability of spin-resolved Landau levels at electron filling factor $ν=n+1/2$, where n is a positive integer. Representing the half-filled topmost Landau level by fermions and the n filled inner Landau levels by n bosons, coupled to the Chern-Simons gauge fields, we show that the ground states exhibit charge density wave order for $n(n+1/2)>15.5

Hans Kroha

Numerous experimental indications suggest that the Hume-Rothery mechanism plays an important role in stabilizing quasicrystalline and amorphous phases. However, the exponential damping of the conventional Friedel oscillations at the relevant, elevated temperatures $T$ poses a severe challenge to the HR stabilization. In order to resolve this problem it is sh

A. Polls, A. Fabrocini

The description of the properties of liquid Helium is a challenge for any microscopic many-body theory. In this context, we study the ground state and the excitation spectrum of one $^3$He impurity in liquid $^4$He at T=0 with the aim of illustrating the power of the correlated basis function formalism in describing heavily correlated systems. The strong int

M. Meneghetti

Electron-phonon and electron-electron interactions are in competition in determining the properties of molecular charge transfer conductors and superconductors. The direct influence of phonons on the electron-electron interaction was not before considered and in the present work the coupling of intramolecular modes to electron-electron interaction (U-vib int

Eduardo Gagliano, Fabian Lema, Silvia Bacci, Juan José Vicente

We use a high-statistic quantum Monte Carlo and Maximum Entropy regularization method to compute the dynamical energy correlation function (DECF) of the one-dimensional (1D) $S=1/2$ antiferromagnetic Heisenberg model at finite temperatures. We also present a finite temperature analytical ansatz for the DECF which is in very good agreement with the numerical

D. H. E. Gross, E. Votyakov

Traditionally, phase transitions are defined in the thermodynamic limit only. We discuss how phase transitions of first order (with phase separation and surface tension), continuous transitions and (multi)-critical points can be seen and classified for small systems. Boltzmann defines the entropy as the logarithm of the area W(E,N)=e^S(E,N) of the surface in

G. Kießlich, A. Wacker, E. Schöll

The transmission through quantum wires is studied within a noninteracting model taking into account the geometry of cleaved edge overgrowth devices. We show that the junction between wide contact and narrow wire has almost no influence on the transmission through these devices while a potential step between contact and wire strongly effects the conduction. O

M. Yu. Kagan, M. A. Baranov, Yu. Kagan, D. S. Petrov

We predict a possibility of triplet Cooper pairing in a Fermi-gas of neutral particles in a confined geometry of magnetic traps at ultra-low temperatures. We evaluate a superfluid transition temperature and analyze the difference between pairing in free space and in confined geometry. We also consider in details a case of fermionic 6Li.

U. S. Schwarz, G. Gompper

We study the phase behavior of ternary amphiphilic systems in the framework of a curvature model with non-vanishing spontaneous curvature. The amphiphilic monolayers can arrange in different ways to form micellar, hexagonal, lamellar and various bicontinuous cubic phases. For the latter case we consider both single structures (one monolayer) and double struc

Jutta Luettmer-Strathmann

Processes on different length scales affect the dynamics of chain molecules. In this work, we focus on structures on the scale of a monomer and investigate polyolefins, i.e. hydrocarbon chains with different small scale architectures. We present an exact enumeration scheme for the simulation of interactions and relative motion of two short chain sections on

Christopher Manderfeld, Henning Schomerus

We study how the singular behaviour of classical systems at bifurcations is reflected by their quantum counterpart. The semiclassical contributions of individual periodic orbits to trace formulae of Gutzwiller type are known to diverge when orbits bifurcate, a situation characteristic for systems with a mixed phase space. This singular behaviour is reflected

Koichi Fujimoto, Kunihiko Kaneko

Sensitive boundary condition dependence (BCD) is reported in a convectively unstable system with noise, where the amplitude of generated oscillatory dynamics in the downstream depends sensitively on the boundary value. This BCD is explained in terms of the manner in which the co-moving Lyapunov exponent (characterizing the convective instability) decreases f

H. Grigorian, G. Poghosyan, E. Chubarian, D. Blaschke

The occurence of a quark matter core in rotating compact stars has been investigated within general relativity as a function of both the rotational frequency and the total baryon number. We demonstrate that the deviation of the braking index from $n=3$ signals not only the occurence but also the size of a quark matter core in a pulsar. We suggest that in sys

Y. Terashima, L. C. Ho, A. F. Ptak, R. F. Mushotzky

We present ASCA observations of LINERs without broad H$α$ emission in their optical spectra. The sample of "type 2" LINERs consists of NGC 404, 4111, 4192, 4457, and 4569. We have detected X-ray emission from all the objects except for NGC 404; among the detected objects are two so-called transition objects (NGC 4192 and NGC 4569), which have been po

Jason Tumlinson, J. Michael Shull

We present stellar structure and atmosphere models of metal-free stars and examine them from a cosmological point of view. Metal-free stars exhibit high effective temperatures and small sizes relative to metal-enriched stars of equal mass. These unique physical characteristics enhance the ionizing photon production by metal-free stars, particularly in the He

Luciano Mantegazza, Filippo M. Zerbi, Alberto Sacchi

The delta Scuti star X Caeli has been the target of a simultaneous photometric (14 consecutive nights) and spectroscopic campaign (8 consecutive nigths). From the analysis of light curves we were able to pick up 17 frequency components, most of which were already detected in two previous campaigns. The comparison with the results of the previous campaigns sh

Craig L. Sarazin, Joshua C. Kempner

We have calculated nonthermal bremsstrahlung (NTB) models for the hard X-ray (HXR) tails recently observed by BeppoSAX in clusters of galaxies. In these models, the HXR emission is due to suprathermal electrons with energies of about 10-200 keV. Under the assumption that the suprathermal electrons form part of a continuous spectrum of electrons including hig

G. Bodo, W. Kalkofen, S. Massaglia, P. Rossi

We investigate analytically the propagation of linear waves in a three-dimensional, nonmagnetic, isothermal atmosphere stratified in plane-parallel layers. The motivation is to study oscillations in the non-magnetic chromosphere and to assess the limitations of one-dimensional simulations of the Kv bright point phenomenon. We consider an impulsively excited

Steen Hannestad

The reconstruction of the CMBR power spectrum from a map represents a major computational challenge to which much effort has been applied. However, once the power spectrum has been recovered there still remains the problem of extracting cosmological parameters from it. Doing this involves optimizing a complicated function in a many dimensional parameter spac

S. Andreon, R. Pello'

We present the near-infrared H band luminosity function (hereafter LF) of the Coma cluster of galaxies. It is the deepest ever computed in the near-infrared, for any type of environment, extending over 7 magnitudes, down to ~M_H*+6. The LF was computed on a near-infrared selected sample of galaxies which photometry, complete down to the typical dwarf luminos

X. Kong, F. Z. Cheng

Blue compact galaxies (BCGs) are compact galaxies that are dominated by intense star formation. Comparing the observational properties with the predictions of stellar population synthesis model, we have analyzed the nuclear stellar population and emission line spectra in a sample of 10 BCGs. The results indicate that the continuum flux fractions at 5870Å due

Matthew Colless

Redshift surveys are one of the prime tools of observational cosmology. Imaging surveys of the whole sky are now available at a wide range of wavelengths, and provide a basis for the new generation of massive redshift surveys currently in progress. The very large datasets produced by these surveys call for new and sophisticated approaches to the analysis of

Douglas Scott

I review the present status of the Cosmic Microwave Background, with some emphasis on the current and future implications for particle physics. Conclusions are: gravitational instability in a dark matter dominated universe grew today&#39;s structure; the Universe remained neutral until z<~50; the CMB power spectrum peaks at 150<~l<~350; the large-scale struc

Una Hwang, Robert Petre, John P. Hughes

The Galactic supernova remnant W49B has one of the most impressive X-ray emission line spectra obtained with the Advanced Satellite for Cosmology and Astronomy (ASCA). We use both plasma line diagnostics and broadband model fits to show that the Si and S emission lines require multiple spectral components. The spectral data do not necessarily require individ

Ming Sun, Zhenru Wang

Based on the data from the \asca observation of SNRs Kes79 and W49B, we present here the analysis of their X-ray spectra and morphologies. The Kes79 spectrum can be well fitted by a single NEI component, and the narrow-band images of that source show an inhomogeneous distribution of heavy elements. The heavy elements are richest in the positions S, SE and SW

J. Bell, R. Manchester, F. Crawford, A. Lyne

The Parkes multibeam pulsar survey began in 1997 and is now about 50% complete. It has discovered more than 400 new pulsars so far, including a number of young, high magnetic field, and relativistic binary pulsars. Early results, descriptions of the survey and follow up timing programs can be found in papers by Lyne et al. (1999 MNRAS in press, astro-ph/9911

Brian D. Fields, Keith A. Olive, Elisabeth Vangioni-Flam, Michel Casse

The nucleosynthesis of Be and B by spallation processes provides unique insight into the origin of cosmic rays. Namely, different spallation schemes predict sharply different trends for the growth of LiBeB abundances with respect to oxygen. ``Primary&#39;&#39; mechanisms predict BeB $\propto$ O, and are well motivated by the data if O/Fe is constant at low m

R. N. Manchester, A. G. Lyne, F. Camilo, V. M. Kaspi

Measurement of accurate positions, pulse periods and period derivatives is an essential follow-up to any pulsar survey. The procedures being used to obtain timing parameters for the pulsars discovered in the Parkes multibeam pulsar survey are described. Completed solutions have been obtained so far for about 80 pulsars. They show that the survey is preferent

D. R. Lorimer

A look back at the recent IAU meeting &#34;Pulsar Astronomy 2000 and beyond&#34; held in Bonn.

P. Sriganesh, R. Bursill, C. J. Hamer

A new finite lattice calculation of the low lying bound state energies in the massive Schwinger model is presented, using a Hamiltonian lattice formulation. The results are compared with recent analytic series calculations in the low mass limit, and with a new higher order non-relativistic series which we calculate for the high mass limit. The results are ge

Kenneth Wood, Abraham Loeb

We use a three-dimensional radiation transfer code to calculate the steady-state escape fraction of ionizing photons from disk galaxies as a function of redshift and galaxy mass. The gaseous disks are assumed to be isothermal (with a sound speed $c_s\sim 10~{\rm km~s^{-1}}$) and radially exponential. Their scale-radius is related to the characteristic spin p

A. Scala, M. R. Sadr-Lahijany, N. Giovambattista, S. V. Buldyrev

We consider the novel properties of the Stell-Hemmer core-softened potentials. First we explore how the theoretically predicted second critical point for these potentials is related to the occurrence of the experimentally observed solid-solid isostructural critical point. We then discuss how this class of potentials can generate anomalies analogous to those

S. Tomsovic, Mikkel B. Johnson, A. Hayes, J. D. Bowman

We present the first application of statistical spectroscopy to study the root-mean-square value of the parity nonconserving (PNC) interaction matrix element M determined experimentally by scattering longitudinally polarized neutrons from compound nuclei. Our effective PNC interaction consists of a standard two-body meson-exchange piece and a doorway term to

L. Canton, W. Schadow

We test the presence of pion-nucleon isoscalar off-shell effects in the $pd\to π^+ t$ reaction around the threshold region. We find that these effects significantly modify the production cross section and that they may provide the missing strength needed to reproduce the data at threshold.

Agapitos Hatzinikitas

We search for a real bosonic and fermionic action in four dimensions which both remain invariant under local Weyl transformations in the presence of non-metricity and contortion tensor. In the presence of the non-metricity tensor the investigation is extended to Weyl $(W_n, g)$ space-time while when the torsion is encountered we are restricted to the Riemann

T. Plehn, D. Rainwater, D. Zeppenfeld

Weak boson fusion promises to be a copious source of intermediate mass Higgs bosons at the LHC. The additional very energetic forward jets in these events provide for powerful background suppression tools. We analyze the subsequent H -> tau tau -> e mu pTmiss decay for Higgs boson masses in the 100-150 GeV range. A parton level analysis of the dominant backg

K. Landsteiner, E. Lopez

String or M-theory in the background of Kerr-AdS black holes is thought to be dual to the large n limit of certain conformal field theories on a rotating sphere at finite temperature. The five dimensional black hole is associated to N=4 supersymmetric Yang-Mills theory on a rotating three-sphere and the four dimensional one to the superconformal field theory

Andrew Collier Cameron, Keith Horne, Alan Penny, David James

Giant planets orbiting stars other than the Sun are clearly detectable through precise radial-velocity measurements of the orbital reflex motion of the parent star. In the four years since the discovery of the companion to the star 51 Peg, similar low-amplitude ``Doppler star wobbles&#39;&#39; have revealed the presence of some 20 planets orbiting nearby sol

Arun K. Pati

For any bipartite quantum system the Schmidt decomposition allows us to express the state vector in terms of a single sum instead of double sums. We show the existence of the Schmidt decomposition for tripartite system under certain condition. If the partial inner product of a basis (belonging to a Hilbert space of smaller dimension) with the state of the co