September 2002 arXiv papers — page 22

S. K. Roushon

In this paper we generalize the notion of strongly poly-free group to a larger class of groups, we call them strongly poly-surface groups and prove that the Fibered Isomorphism Conjecture of Farrell and Jones corresponding to the stable topological pseudoisotopy functor is true for any virtually strongly poly-surface group. A consequence is that the Whitehea

A. Yu. Voronin, J. Carbonell

Annihilation cross-section of ultra low-energy atomic antihydrogen ($% E\le10^{-5}$ a.u.) on atomic hydrogen are calculated within a quantum mechanical coupled channels approach. The results differ from the extrapolations of semiclassical models to low energies. The main features of the observables are found to be determined by a family of $H\bar{H}$ nearthr

Wung-Hong Huang

The effective action of a free scalar field propagating in the generalized Godel spacetime is evaluated by the zeta-function regularization method. From the result we show that the renormalized stress energy tensor may be divergent at the chronology horizon. This gives a support to the chronology protection conjecture.

N. R. Sibgatullin, A. Garcia, V. S. Manko

An efficient method is developed which allows the calculation of distributions of the surface density in the equilibrium disk configurations with an isolated point mass at the center corresponding to known distributions of the angular velocity. We demonstrate the existence of the upper limit for the ratio `mass of the galactic disk / mass of the central blac

Steffen A. Bass, Berndt Müller, Dinesh K. Srivastava

We calculate the production of high energy photons from Compton and annihilation processes as well as fragmentation off quarks in the parton cascade model. The multiple scattering of partons is seen to lead to a substantial production of high energy photons, which rises further when parton multiplication due to final state radiation is included. The photon y

L. Tessieri, J. Wilkie

A low temperature model system consisting of a central spin coupled to a spin-bath is studied to determine whether interaction among bath spins has an effect on central spin dynamics. In the absence of intra-environmental coupling, decoherence of the central spin is fast and irreversible. Strong intra-environmental interaction results in an effective decoupl

Patrick Navez

We propose an experimental set up allowing to convert an input light of wavelengths about $1-2 μm$ into an output light of a lower frequency. The basic principle of operating relies on the nonlinear optical properties exhibited by a microcavity filled with glass. The light inside this material behaves like a 2D interacting Bose gas susceptible to thermalise

G. Kaniadakis, A. M. Scarfone

We consider a wide class of nonlinear canonical quantum systems described by a one-particle Schroedinger equation containing a complex nonlinearity. We introduce a nonlinear unitary transformation which permits us to linearize the continuity equation. In this way we are able to obtain a new quantum system obeying to a nonlinear Schroedinger equation with a r

Koji Usami, Yoshihiro Nambu, Yoshiyuki Tsuda, Keiji Matsumoto

We experimentally analyzed the statistical errors in quantum-state estimation and examined whether their lower bound, which is derived from the Cramer-Rao inequality, can be truly attained or not. In the experiments, polarization states of bi-photons produced via spontaneous parametric down-conversion were estimated employing tomographic measurements. Using

A. Rivero

The level splitting formula of an asymmetric double well potential is calculated taking into account the multi-instanton contributions (dilute gas approximation). Results can be related with known semiclassical ones obtained with a truncated hamiltonian, and the symmetric case is easily recovered.

G. Gilbert, M. Hamrick

A number of questions associated with practical implementations of quantum cryptography systems having to do with unconditional secrecy, computational loads and effective secrecy rates in the presence of perfect and imperfect sources are discussed. The different types of unconditional secrecy, and their relationship to general communications security, are di

Juan Pablo Neirotti, Nestor Caticha

We study the evolution of artificial learning systems by means of selection. Genetic programming is used to generate a sequence of populations of algorithms which can be used by neural networks for supervised learning of a rule that generates examples. In opposition to concentrating on final results, which would be the natural aim while designing good learni

E. A. Kuznetsov

It is shown that the Euler hydrodynamics for vortical flows of an ideal fluid coincides with the equations of motion of a charged {\it compressible} fluid moving due to a self-consistent electromagnetic field. Transition to the Lagrangian description in a new hydrodynamics is equivalent for the original Euler equations to the mixed Lagrangian-Eulerian descri

J. S. Hunjan, S. Sarkar, R. Ramaswamy

Locating the global minimum of a complex potential energy surface is facilitated by considering a homotopy, namely a family of surfaces that interpolate continuously from an arbitrary initial potential to the system under consideration. Different strategies can be used to follow the evolving minima. It is possible to enhance the probability of locating the g

Mark P. Davidson

A description of an algorithm for a rather general modal grating calculation is presented. Arbitrary profiles, depth, and permittivity are allowed. Gratings built up from sub-gratings are allowed, as are coatings on the sidewalls of lines, and arbitrary complex structure. Conical angles and good conductors are supported.

Vincent Morin

Those articles (versions) explore a non conventional pregeometrical model encompassing quantics and geometrodynamics (a stochastic graph relational theory). Some key points are : 1) the use of simple boolean atom-like far subquantum entities connected with action links deriving from probabilistic laws (acteons). 2) the concept of structures as correlated net

Michail P. Rekalo, Egle Tomasi-Gustafsson

Polarization phenomena are essential for the understanding of elementary processes, and are typically large in the threshold region. The selection rules with respect to P-parity, angular momentum, isotopic spin and the Pauli principle allow to parametrize in a model independent way, the spin structure of the matrix elements for the near-threshold heavy meson

Alan Champneys, Jianke Yang

An explanation is given for previous numerical results which suggest a certain bifurcation of `vector solitons' from scalar (single-component) solitary waves in coupled nonlinear Schroedinger (NLS) systems. The bifurcation in question is nonlocal in the sense that the vector soliton does not have a small-amplitude component, but instead approaches a soli

Zoltan Neufeld, Cristobal Lopez, Emilio Hernandez-Garcia, Oreste Piro

We investigate the response of an excitable medium to a localized perturbation in the presence of a two-dimensional smooth chaotic flow. Two distinct types of flows are numerically considered: open and closed. For both of them three distinct regimes are found, depending on the relative strengths of the stirring and the rate of the excitable reaction. In orde

Dhurjati Prasad Datta

A new class of finitely differentiable scale free solutions to the simplest class of ordinary differential equations is presented. Consequently, the real number set gets replaced by an extended physical set, each element of which is endowed with an equivalence class of infinitesimally separated neighbours in the form of random fluctuations. We show how a sen

Ernie Croot, Christian Elsholtz

Suppose that P is an infinite set of primes such that P = A + B + C, where A,B,C are sets with at least two elements. We show that if P(x) > c x/log^d x (where P(x) = the number of elements of P that are <= x), and if A,B,C is a &#34;regular&#34; triple of sets, then either |A+B| <= d, or |B+C| <= d, or |A+C| <= d.

Arun Ram, Anne V. Shepler

The graded Hecke algebra for a finite Weyl group is intimately related to the geometry of the Springer correspondence. A construction of Drinfeld produces an analogue of a graded Hecke algebra for any finite subgroup of GL(V). This paper classifies all the algebras obtained by applying Drinfeld&#39;s construction to complex reflection groups. By giving expli

S. Paul Smith

We examine maps between noncommutative projective spaces. A surjection of graded rings A-->A/J induces a closed immersion Proj(A/J)-->Proj(A). A homomorphism f:A-->B between graded rings induces an affine map U --> Proj(A) from a non-empty open subspace U of Proj(B). If A^{(n)} is the n-th Veronese subalgebra of a graded ring A there is a map Proj(A)-->Proj(

Maxim Nazarov

The Yangian of the Lie algebra $gl_N$ has a distinguished family of irreducible finite-dimensional representations, called elementary representations. They are parametrized by pairs, consisting of a skew Young diagram and a complex number. Each of these representations has an explicit realization, it extends the classical realization of the irreducible polyn

A. H. Zemanian

An ordinal-valued metric taking its values in the set of all countable ordinals can be assigned to a metrizable set of nodes in a transfinite graph. Then, a variety of results concerning nodal eccentricities, radii, diameters, centers, peripheries, and blocks can be extended to transfinite graphs.

Robert O. Bauer

We study the horizontal Laplacian $Δ^H$ associated to the Hopf fibration $S^3\to S^2$ with arbitrary Chern number $k$. We use representation theory to calculate the spectrum, describe the heat kernel and obtain the complete heat trace asymptotics of $Δ^H$. We express the Green functions for associated Poisson semigroups and obtain bounds for their contractio

B. Feigin, M. Jimbo, T. Miwa, E. Mukhin

For a pair of positive integers (k,r) with r>1 such that k+1 and r-1 are relatively prime, we describe the space of symmetric polynomials in variables x_1,...,x_n which vanish at all diagonals of codimension k of the form x_i=tq^{s_i}x_{i-1}, i=2,...,k+1, where t and q are primitive roots of unity of orders k+1 and r-1.

Paul S. Muhly, Dana P. Williams

We give a formula for the Dixmier-Douady class of a continuous-trace groupoid crossed product that arises from an action of a locally trivial, proper, principal groupoid on a bundle of elementary $C^*$-algebras that satisfies Fell&#39;s condition.

A. N. W. Hone

We consider a fourth order partial differential equation in n-dimensional space introduced by Abreu in the context of Kähler metrics on toric orbifolds. Similarity solutions depending only on the radial coordinate in R^n are determined in terms of a second order ordinary differential equation. A local asymptotic analysis of solutions in the neighbourhood of

Michael G. Eastwood

Mather and Yau showed that an isolated complex hypersurface singularity is completely determined by its moduli algebra. It is shown, for the simple elliptic singularities, how to construct continuous invariants from the moduli algebras and, hence, associate invariants to the singularities themselves.

Annette Werner

We construct a compactification of the Bruhat-Tits building associated to the group PGL(V) which can be identified with the space of homothety classes of seminorms on V endowed with the topology of pointwise convergence. Then we define a continuous map from the projective space to this compactification which extends the reduction map from Drinfeld&#39;s p-ad

Amit Khetan

This paper gives an explicit method for computing the resultant of any sparse unmixed bivariate system with given support. We construct square matrices whose determinant is exactly the resultant. The matrices constructed are of hybrid Sylvester and Bézout type. We make use of the exterior algebra techniques of Eisenbud, Fløystad, and Schreyer.

E. Esteves, S. Kleiman

Let X be a variety over an algebraically closed field, η:Ω^1_X\to L a one-dimensional singular foliation, and C\subseteq X a projective leaf of η. We prove that 2p_a(C)-2=°(L|C)+λ(C)-°(C\cap S) where p_a(C) is the arithmetic genus, where λ(C) is the colength in the dualizing sheaf of the subsheaf generated by the Kähler differentials, and where S is the sing

Yan Soibelman

Classical Borsuk problem asks about the minimal number of closed subsets of smaller diameter necessary to partition every compact in the Euclidean space. Topological version of the Borsuk problem is discussed.

Eric Babson, Paul E. Gunnells, Richard Scott

Let X^{circ} be the space of all labeled tetrahedra in P^{3}. In [BGS] we constructed a smooth symmetric compactification X-tilde of X^{circ}. In this article we show that the complement X-tilde smallsetminus X^{circ} is a divisor with normal crossings, and we compute the cohomology ring H^*(X-tilde;Q).

Patrick Erik Bradley

Moduli spaces for Galois covers of p-adic Mumford curves by Mumford curves are constructed using Herrlich&#39;s Teichmuller spaces, Andre&#39;s orbifold fundamental groups, and Kato&#39;s graphs of groups encoding ramification data of charts for Mumford orbifolds.

Bernard Leclerc

Let $n$ be the maximal nilpotent subalgebra of a simple complex Lie algebra $g$. We introduce the notion of imaginary vector in the dual canonical basis of $U_q(n)$, and we give examples of such vectors for types $A_n (n\ge 5)$, $B_n (n\ge 3)$, $C_n (n\ge 3)$, $D_n (n\ge 4)$, and all exceptional types. This disproves a conjecture of Berenstein and Zelevinsky

Ronald Umble

Let H be a differential graded Hopf algebra over a field k. This paper gives an explicit construction of a triple cochain complex that defines the Hochschild-Cartier cohomology of H. A certain truncation of this complex is the appropriate setting for deforming H as an H(q)-structure. The direct limit of all such truncations is the appropriate setting for def

K. Kleidis, A. Kuiroukidis, D. B. Papadopoulos

A quadratic semiclassical theory, regarding the interaction of gravity with a massive scalar quantum field, is considered in view of the renormalizable energy-momentum tensor in a multi-dimensional curved spacetime. According to it, a self-consistent coupling between the square curvature term R^{2} and the quantum field Φshould be introduced in order to yiel

Wung-Hong Huang

We use a perturbative method to evaluate the effective action of a free scalar field propagating in the Bianchi type I spacetime with large space anisotropy. The zeta- function regularization method is used to evaluate the action to the second order in the Schwinger perturbative formula. As the quantum corrections contain fourth derivative in the metric we a

V. Dzhunushaliev

At present an algebra of strongly interacting fields is unknown. In this paper it is assumed that the operators of strongly nonlinear field can form a non-associative algebra. It is shown that such algebra can be described as an algebra of some pairs. The comparison of presented techniques with the Green&#39;s functions method in the superconductivity theory

Oliver Brein

We show some results in the minimal supersymmetric Standard Model (MSSM) and the two Higgs doublet model (THDM) for W+/- H-/+ production cross sections at e+ e- and hadron colliders. We demonstrate that the predictions for the cross sections in the two models can be vastly different. Observing these processes, once the existence of a charged Higgs is establi

N. Okamura

This is a contribution paper of the XXth International Conference on Neutrino Physics and Astrophysics (Neutrino2002) and YITP workshop.

Rodolfo A. Diaz, R. Martinez, Nicanor Poveda

We consider the process $μ\to ν_{e}e\barν_μ $in the framework of a two Higgs doublet model with flavor changing neutral currents (FCNC). Since FCNC generates in turn flavor changing charged currents in the lepton sector, this process appears at tree level mediated by a charged Higgs boson exchange. From the experimental upper limit for this decay, we obtain

D. N. Triantafyllopoulos

We study the energy dependence of the saturation momentum in the context of the collinearly improved Leading and Next to Leading BFKL evolution, and in the presence of saturation boundaries. We find that the logarithmic derivative of the saturation momentum is varying very slowly with Bjorken-x, and its value is in agreement with the Golec-Biernat and Wustho

Stephen M. H. Wong, Joseph I. Kapusta

Rare hyperon yields such as the Omega and AntiOmega in heavy ion collision experiments are hard to be reproduced by numerical models. This, in combination with the thermal fit to SPS data, seems to call for a new production mechanism beyond the usual ones. Small domain disoriented chiral condensates (DCC) were proposed to be such a source of rare hyperons th

Gabriela Barenboim, Andre de Gouvea

The neutrino community is convinced that if the LMA solution is indeed correct, the prospects for next-generation, long-baseline neutrino experiments are very exciting. In this work we will argue that the prospects are not less exiting if the answer to the solar neutrino puzzle lies in the LOW region. For this purpose we explore the oscillation probabilities

Kazuyuki Kanaya

I summarize recent lattice results on QCD at finite temperatures and densities. Studies on the nature of the QCD transition at the physical point, continuum extra polations of thermodynamic quantities, and new calculations of hadronic spectral functions applying the maximum entropy method are discussed. Recent advances in finite density QCD are also reviewed

Yutaka Hosotani, Hiroki Emoto, Takahiro Kubota

In the SU(2)_L x U(1)_Y standard electroweak theory coupled with the Einstein gravity, new topological configurations naturally emerge, if the spatial section of the universe is globally a three-sphere (S^3) with a small radius. The SU(2)_L gauge fields wrap the space nontrivially, producing homogeneous but anisotropic space. As the universe expands, large e

N. Ishizuka

Recent theoretical and numerical progresses of the lattice calculations of $K\toππ$ decay amplitude are reviewed.

C. J. D. Lin, G. Martinelli, E. Pallante, C. T. Sachrajda

We present the inconsistencies which arise in quenched QCD in $ΔI=1/2$ non-leptonic kaon decays using chiral perturbation theory (ChPT) to one loop. In particular we discuss how the lack of unitarity of the quenched theory invalidates the usual methods for the extraction of matrix elements from correlation functions.

J. Engelfried, P. S. Cooper, A. Morelos, I. Torres

We present the design of two velocity spectrometers, to be used in the recently approved CKM experiment. CKM&#39;s main goal is the measurement of the branching ratio of K+ -> pi+ nu nu with a precision of 10%, via decays in flight of the K+. The design of both RICH detectors is based on the SELEX Phototube RICH. We will discuss the design and the expected p

K. Eitel

We review the status of the search for neutrino oscillations in the short baseline regime with experiments at accelerators. The evidence for numubar->nuebar from the LSND experiment is compared with the negative results of the KARMEN numubar->nuebar search and with the results from NOMAD and NuTeV in the same flavor mixing channel. We describe the upcoming M

Philippe Droz-Vincent

We argue that quantum theory in curved spacetime should be invariant under the continuous spacetime symmetries thaat are connected with the identity. For typical warped-product spacetimes, we prove that such invariance can be actually implemented, at least at the level of first quantization. Our approach rests on a mode decomposition which is special to the

Daniel Murphy, Edgar Genio, Guenter Ahlers, Fengchuan Liu

We present measurements of the thermal resistivity $ρ(t,P,L)$ near the superfluid transition of $^4$He at saturated vapor pressure and confined in cylindrical geometries with radii $L=0.5$ and 1.0 $μ$m ($t\equiv T/T_λ(P) - 1$). For $L = 1.0 μ$m measurements at six pressures $P$ are presented. At and above $T_λ$ the data are consistent with a universal scalin

F. C. Zhang

Gutzwiller variational method is applied to an effective two-dimensional Hubbard model to examine the recently proposed gossamer superconductor by Laughlin. The ground state at half filled electron density is a gossamer superconductor for smaller intra-site Coulomb repulsion U and a Mott insulator for larger U. The gossamer superconducting state is similar t

A. A. Naidenov, S. K. Nechaev

The kinetics of the diffusion-controlled chemical reactions A+A+...+A->0 that occur at catalytic centers periodically arranged along a straight line is considered. Modes of the behavior of reaction probability W(t) were studied at different times and different densities of the catalyst. Within the Smoluchowski approximation, it was rigorously proved that at

S. Deemyad, T. Tomita, J. J. Hamlin, B. R. Beckett

The dependence of Tc for MgB2 on purely hydrostatic or nearly hydrostatic pressure has been determined to 23 GPa for single-crystalline and to 32 GPa for polycrystalline samples, and found to be in good agreement. Tc decreases from 39 K at ambient pressure to 15 K at 32 GPa with an initial slope dTc/dP = -1.11(2) K/GPa. Evidence is presented that the differi

R. B. Laughlin

An new superconducting hamiltonian is introduced for which the exact ground state is the Anderson resonating valence bond. It differs from the t-J and hubbard hamiltonians in possessing a powerful attractive force. Its superconducting state is characterized by a full and intact d-wave tunneling gap, quasiparticle photoemission intensities that are strongly s

Javier Hernandez-Rojas, David J. Wales

Properties of local minima as a function of density are studied in a binary Lennard-Jones system for kinetic equipartition temperatures $T=1.0$ (normal liquid), 0.5 (supercooled liquid), and 0.4 (glass), in reduced units. The number of different local minima sampled, energy, pressure, normal mode angular frequencies, mean distance between all pairs of local

A. Sartori, A. O. Parry

We investigate critical wetting transitions for fluids adsorbed in wedge-like geometries where the substrate height varies as a power-law, $z(x,y) \sim |x| ^γ$, in one direction. As $γ$ is increased from 0 to 1, the substrate shape is smoothly changed from a planar-wall to a linear wedge. The continuous wetting and filling transitions pertinent to these limi

K. E. Hibberd, J. R. Links

We present an electronic model with long range interactions. Through the quantum inverse scattering method, integrability of the model is established using a one-parameter family of typical irreducible representations of gl(2|1). The eigenvalues of the conserved operators are derived in terms of the Bethe ansatz, from which the energy eigenvalues of the Hami

G. Kontrym-Sznajd, M. Samsel, R. N. West

The advent of synchrotron sources has led to an increasing availability of high resolution Compton Profiles J(pz) and a consequent renewed interest in the reconstruction of the corresponding full momentum densities rho(p). We present results of applying a new method in which the radial parts of rho(p) and the measured profiles are expressed in terms of Jacob

F. M. Souza, J. C. Egues, A. P. Jauho

Using the Keldysh nonequilibrium technique we calculate current, noise and Fano factor in a ferromagnetic(FM)-quantum dot-ferromagnetic(FM) system with Coulomb interaction and spin-flip scattering in the dot. The lead polarizations are considered in both parallel P and antiparallel AP alignments. We show that spin-flip can increase both AP-current and AP-noi

D. Y. Vodolazov, F. M. Peeters, S. V. Dubonos, A. K. Geim

An experimental and theoretical investigation was made of flux jumps and irreversible magnetization curves of mesoscopic Al superconducting rings. In the small magnetic field region the change of vorticity with magnetic field can be larger than unity. This behavior is connected with the existence of several metastable states of different vorticity. The inten

G. Kontrym-Sznajd, A. Jura, M. Samsel-Czekala

Rules are given for determining special directions in the Brillouin zone which optimize the descrip-tion of various physical quantities with Gamma1 type symmetry. We consider the cubic, hexagonal, tetragonal and trigonal (e.g. Bi) lattice. These rules allow us to construct, in all of momentum space, quantities which have the full symmetry of the Brillouin zo

G. Simon, M. T. Levinsen

In this paper we present an experimental approach that allows to deduce the important dynamical parameters of single sonoluminescing bubbles (pressure amplitude, ambient radius, radius-time curve) The technique is based on a few previously confirmed theoretical assumptions and requires the knowledge of quantities such as the amplitude of the electric excitat

K. Westerholt, U. Geiersbach, A. Bergmann

We report structural and magnetic properties of multilayers composed of thin layers of the half metallic ferromagnetic Heusler compound Co2MnGe and layers of Au, Cr and the Heusler compound Cu2MnAl. The hysteresis loops measured at low temperatures reveal the existence of an exchange bias field HEB in all of these multilayers. For the [Co2MnGe/Au] multilayer

J. Deisenhofer, H. -A. Krug von Nidda, A. Loidl, M. V. Eremin

We report on Ferromagnetic-Resonance experiments in a single crystal of La_0.8Sr_0.2MnO_3 in the temperature range from 4 to 300 K. The observed anisotropy of the resonance line changes on crossing the transition from the orthorhombic O-phase to the rhombohedral R-phase at T~100 K and indicates a reorientation of the spins at about 130 K.

J. M. An, H. Rosner, S. Y. Savrasov, W. E. Pickett

The search for other superconductors in the MgB2 class currently is focussed on Li{1-x}BC, which when hole-doped (concentration x) should be a metal with the potential to be a better superconductor than MgB2. Here we present the calculated phonon spectrum of the parent semiconductor LiBC. The calculated Raman-active modes are in excellent agreement with a re

J. H. Shim, Kyoo Kim, B. I. Min, J. -S. Kang

We have investigated electronic structures of La$_3$S$_4$ and Ce$_3$S$_4$ using the LSDA and LSDA+$U$ methods. Calculated density of states (DOS) are compared with the experimental DOS obtained by the valence band photoemission spectroscopy. The DOS at $E_{\rm{F}}$ indicates the 5$d$ character in La$_3$S$_4$ and 4$f$ character in Ce$_3$S$_4$. It is found to

Y. L. Zhong, J. J. Lin, L. Y. Kao

Using the weak-localization method, we have measured the electron-phonon scattering times $τ_{ep}$ in Pd$_{60}$Ag$_{40}$ thick films prepared by DC- and RF-sputtering deposition techniques. In both series of samples, we find an anomalous $1/τ_{ep} \propto T^2\ell$ temperature and disorder dependence, where $\ell$ is the electron elastic mean free path. This

Min Sik Park, S. K. Kwon, B. I. Min

The effects of $n$-type carrier doping by Li intercalation on magnetism in undoped and Co-doped anatase TiO$_2$ are investigated. We have found that doped $n$-type carriers in TiO$_2$ are localized mainly at Ti sites near the intercalated Li. With increasing the intercalation, local spins are realized at Ti. In the case of Co-doped TiO$_2$, most of the added

J. J. Moreno, H. G. Katzgraber, Alexander K. Hartmann

Monte Carlo simulation techniques, like simulated annealing and parallel tempering, are often used to evaluate low-temperature properties and find ground states of disordered systems. Here we compare these methods using direct calculations of ground states for three-dimensional Ising diluted antiferromagnets in a field (DAFF) and three-dimensional Ising spin

Heinz-Juergen Schmidt, Marshall Luban

We investigate the ground states of classical Heisenberg spin systems which have point group symmetry. Examples are the regular polygons (spin rings) and the seven quasi-regular polyhedra including the five Platonic solids. For these examples, ground states with special properties, e.g. coplanarity or symmetry, can be completely enumerated using group-theore

Kirill N. Alekseev, Pekka Pietilainen, Alexander A. Zharov, Feodor V. Kusmartsev

We find the conditions for a rectification of electromagnetic wave in a lateral semiconductor superlattice with a high mobility of electrons. The rectification is assisted by a transition to a dissipative chaos at a very high mobility. We show that mechanism responsible for the rectification is a creation of warm electrons in the superlattice miniband caused

E. Giraud, G. Meylan, M. Sapinski, A. Falvard

The distant globular cluster Palomar 13 has been found to have a very high mass-to-light ratio and its profile can be well fitted either by a King model with a tail, or with a NFW model. This cluster may be the first case of the many clumps predicted by CDM simulations that would not be disrupted by the galactic halo potential. We make the hypothesis that Pa

Naomi Ota, Makoto Hattori, Etienne Pointecouteau, Kazuhisa Mitsuda

We present the X-ray analysis and the mass estimation of the lensing cluster of galaxies CL0024+17 with Chandra. We found that the temperature profile is consistent with being isothermal and the average X-ray temperature is 4.47 (+0.83, -0.54) keV. The X-ray surface brightness profile is represented by the sum of emissions associated with the central three b

K. E. Haisch, M. Barsony, T. P. Greene, M. E. Ressler

We present new near- and mid-infrared observations of 19 Class I/flat-spectrum young stellar objects in the nearby Rho Oph (d=125pc) and Serpens (d=310pc) dark clouds. These observations are part of a larger systematic infrared multiplicity survey of Class I/flat-spectrum objects in the nearest dark clouds. We find 7/19 (37% +/- 14%) of the sources surveyed

Je-An Gu

As indicated by Einstein&#39;s general relativity, matter and geometry are two faces of a single nature. In our point of view, extra dimensions, as a member of the {\em geometry face}, will be treated as a part of the {\em matter face} when they are beyond our poor vision, thereby providing dark energy sources effectively. The geometrical structure and the e

Eline Tolstoy

Here we report some results from an ESO-VLT programme to observe individual stars in nearby dwarf galaxies at high resolution with the UVES spectrograph (Tolstoy, Venn, Shetrone, Primas, Hill, Kaufer & Szeifert 2002, submitted to AJ). We mainly concentrate on illustrating the issues and uncertainties surrounding our efforts to determine the ages of stars for

K. Nandra, I. Georgantopoulos, A. Ptak, T. J. Turner

We present the SHEEP survey for serendipitously-detected hard X-ray sources in ASCA GIS images. In a survey area of $\sim 40$ deg$^{2}$, 69 sources were detected in the 5-10 keV band to a limiting flux of $\sim 10^{-13}$ erg cm$^{-2}$ s$^{-1}$. The number counts agree with those obtained by the similar BeppoSAX HELLAS survey, and both are in close agreement

E. P. Mazets, R. L. Aptekar, D. D. Frederiks, S. V. Golenetskii

Observational data on the short GRBs obtained with the GGS-Wind Konus experiment in the period from 1994 to 2002 are presented. The catalog currently includes 130 events, detailing their appearance rate, time histories, and energy spectra. Evidence of an early X-ray and gamma-ray afterglow for some of the short GRBs is discussed. The catalog is available ele

Torsten A. Ensslin, Huub Roettgering

A significant fraction of galaxy clusters exhibits cluster wide radio halos. We give a simple prediction of the local and higher redshift radio halo luminosity function (RHLF) on the basis of (i) an observed and a theoretical X-ray cluster luminosity function (XCLF) (ii) the observed radio--X-ray luminosity correlation (RXLC) of galaxy clusters with radio ha

Eija Laurikainen, Heikki Salo

Non-axisymmetric forces are presented for 107 spiral galaxies using the 2 Micron All Sky Survey (2MASS) images. We apply both Cartesian integration and a polar grid integration utilizing a limited number of azimuthal Fourier components of density. We found that bar strength is independent of the method used to evaluate the gravitational potential. However, t

Komissarov SS

Some of the parameters of the test problems for numerical relativistic MHD given in Table 1 in Komissarov(1999) are incorrect. Here we give the correct values.

G. Chauvin, T. Fusco, A-M. Lagrange, D. Mouillet

We present new, high angular resolution images of HD 199143 in the Capricornus association, obtained with the adaptive optics system ADONIS+SHARPII at the ESO 3.6m Telescope of La Silla Observatory. HD 199143 and its neighbour star HD 358623 (separation 5&#39;away) have previously been imaged with adaptive optics. For each star, a companion has been detected

M. Sereno

Observations of clusters of galaxies that gravitationally lens faint background galaxies can probe the amount and the equation of state, $\5$, of the dark energy (quintessence) in the universe. Provided that the mass profile and the mass normalization of the cluster are determined, it is possible to constrain the cosmological parameters that enter the lensin

Vicent J. Martinez, Enn Saar

The main tools in cosmology for comparing theoretical models with the observations of the galaxy distribution are statistical. We will review the applications of spatial statistics to the description of the large-scale structure of the universe. Special topics discussed in this talk will be: description of the galaxy samples, selection effects and biases, co

N. Delmotte, C. Loup, D. Egret, M. -R. Cioni

The Master Catalogue of stars towards the Magellanic Clouds (MC2) is a multi-wavelength reference catalogue. The current paper presents the first results of the MC2 project. We started with a massive cross-identification of the two recently released near-infrared surveys: the DENIS Catalogue towards the Magellanic Clouds (DCMC) with more than 1.3 million sou

M. Catelan, A. V. Sweigart, B. J. Pritzl, H. A. Smith

We discuss the Oosterhoff classification of the unusual, metal-rich globular clusters NGC 6388 and NGC 6441, on the basis of new evolutionary models computed for a range of metallicities. Our results confirm the difficulty in unambiguously classifying these clusters into either Oosterhoff group, and also question the view that RR Lyrae stars in Oosterhoff ty

Linhua Jiang, Jun Ma, Xu Zhou, Jiansheng Chen

This paper is the first in a series presenting CCD multicolor photometry for 145 HII regions, selected from 369 candidate regions from Boulesteix et al. (1974), in the nearby spiral galaxy M33. The observations, which covered the whole area of M33, were carried out by the Beijing Astronomical Observatory 60/90 cm Schmidt Telescope, in 13 intermediate-band fi

Peter P. Eggleton

We discuss the evolution of binaries with moderately high masses (about 10 - 30 solar masses), and with periods of about 3 - 300d, corresponding mostly to early Case B. These are usually thought to evolve either by reasonably conservative Roche-lobe overflow, if the initial mass ratio is fairly mild, or else by highly non-conservative common-envelope evoluti

F. P. Gavriil, V. M. Kaspi, P. M. Woods

Anomalous X-ray Pulsars (AXPs) are a class of rare X-ray pulsars whose energy source has been perplexing for some 20 years. Unlike other, better understood X-ray pulsars, AXPs cannot be powered by rotation or by accretion from a binary companion, hence the designation ``anomalous.&#39;&#39; AXP rotational and radiative properties are strikingly similar to th

Peter P. Eggleton, Ludmila Kiseleva-Eggleton

We apply a model of dynamo-driven mass loss, magnetic braking and tidal friction to the evolution of stars with cool convective envelopes; in particular we apply it to binary stars where the combination of magnetic braking and tidal friction can cause angular-momentum loss from the {\it orbit}. For the present we consider the simplification that only one com

Andrew Cumming, Geoffrey W. Marcy, R. Paul Butler, Steven S. Vogt

We present an analysis of precision radial velocity measurements for 580 stars from the Keck survey. We first discuss the detection threshold of the survey, and then describe a Bayesian approach to constrain the distribution of extrasolar planet orbital parameters using both detections and upper limits.

Andrew Cumming

I discuss the evolution of the magnetic field of an accreting white dwarf. I show that the ohmic decay time is 7-12 billion years for the lowest order decay mode, almost independent of core temperature or mass. I then show that the magnetic field structure is substantially altered by accretion if the white dwarf mass increases at a rate more than 1-5 x 10^(-

Gianfranco Bertone, Claudia Isola, Martin Lemoine, Guenter Sigl

We extend existing work on the propagation of ultra-high energy cosmic rays in extragalactic magnetic fields to a possible component of heavy nuclei, taking into account photodisintegration, pion production, and creation of e+e- pairs. We focus on the influence of the magnetic field on the spectrum and chemical composition of observed ultra-high energy cosmi

Juri Poutanen, Andrzej A. Zdziarski

Recent advances in the X-ray and soft gamma-ray observations of accreting black holes and microquasars, in particular, are reviewed. The radiative processes responsible for the emission are discussed briefly. The hybrid thermal/nonthermal Comptonization model is shown to describe well the observed broad-band spectra. We also comments on alternative phenomeno

Jeremy L. Tinker, Barbara S. Ryden

We investigate the effect of rotating, triaxial halos on disk galaxies through an extensive set of numerical N-body simulations. Our simulations use a rigid potential field for the halos and bulges and collisionless particles for the disks. The triaxiality and the rotation rate of the halo are varied, as well as the masses of all three galaxy components. We