June 2000 arXiv papers — page 14

D. Queloz, A. Eggenberger, M. Mayor, C. Perrier

We report the first detection of a planetary transit by spectroscopic measurements. We have detected the distortion of the stellar line profiles during a planetary transit. With the ELODIE spectrograph we took a sequence of high precision radial velocities of the star HD209458 at time of a transit of its planet. We detected an anomaly in the residuals of the

M. Micono, G. Bodo, S. Massaglia, P. Rossi

The analysis of the stability properties of astrophysical jets against Kelvin-Helmholtz (or shear-layer) instabilities plays a basic role in the understanding the origin and physical characteristics of these objects. Numerical simulations by Bodo et al. (1998) have shown that the three-dimensional non-linear evolution of KH instabilities in supersonic jets i

L. Testi, P. Hofner, S. Kurtz, M. Rupen

We present new high resolution and high sensitivity multi-frequency VLA radio continuum observations of the G9.62+0.19-F hot molecular core. We detect for the first time faint centimetric radio continuum emission at the position of the core. The centimetric continuum spectrum of the source is consistent with thermal emission from ionised gas. This is the fir

Giovanni Imponente, Costantino Sigismondi

The intense activity of cratering on the Moon and in the inner regions of the solar system was accomplished during the first 10^9 years [1]. Occasionally, some impact events occur even nowadays. In Section 1, we treat, from a historical point of view, the Earth-based observation of lunar impacts. In Section 2, we consider the visibility conditions of such ev

Harald Krüger, Alexander V. Krivov, Eberhard Grün

A dust cloud of Ganymede has been detected by in-situ measurements with the dust detector onboard the Galileo spacecraft. The dust grains have been sensed at altitudes below five Ganymede radii (Ganymede radius = $\rm 2,635 km$). Our analysis identifies the particles in the dust cloud surrounding Ganymede by their impact direction, impact velocity, and mass

Valerio Bozza

The cusps of the caustics of any gravitational lens model can be classified into positive and negative ones. This distinction lies on the parity of the images involved in the creation/destruction of pairs occurring when a source crosses a caustic in a cusp. In this paper, we generalize the former definition of the sign of the cusps. Then we apply it to the b

J. P. Halpern, R. Uglesich, N. Mirabal, S. Kassin

The optical light curve of the energetic gamma-ray burst GRB 991216 is consistent with jet-like behavior in which a power-law decay steepens from t**(-1.22 +/- 0.04) at early times to t**(-1.53 +/- 0.05) in a gradual transition at around 2 d. The derivation of the late-time decay slope takes into account the constant contribution of a host or intervening gal

F. A. Rasio

We have developed a new parallel supercomputer code based on Henon's Monte Carlo method for simulating the dynamical evolution of globular clusters. This new code allows us to calculate the evolution of a cluster containing a realistic number of stars (N ~ 10^5 - 10^6) in about a day of computing time. The discrete, star-by-star representation of the clu

Pawan Kumar, Sarbani Basu

Theoretically calculated power spectra are compares with observed solar p-mode velocity power spectra over a range of mode degree and frequency. The depth for the sources responsible for exciting p-modes of frequency 2.0 mHz is determined from the asymmetry of their power spectra and found to be about 800 km below the photosphere for quadrupole sources and 1

S. Moehler, A. V. Sweigart, W. B. Landsman, U. Heber

Atmospheric parameters (effective temperature Teff, surface gravity log g), masses and helium abundances are derived for 42 hot horizontal branch (HB) stars in the globular cluster NGC 6752. For 19 stars we derive magnesium and iron abundances as well and find that iron is enriched by a factor of 50 on average with respect to the cluster abundance whereas th

C. M. Maekawa, U. van Kolck

The anapole form factor of the nucleon is calculated in chiral perturbation theory in leading order. To this order, the form factor originates from the pion cloud, and is proportional to the non-derivative parity-violating pion-nucleon coupling. The momentum dependence of the form factor - and in particular, its radius - is completely determined by the pion

E. D'Hoker, B. Pioline

We present conjectures for the space-time form and leading large N dependence of extremal and near-extremal correlation functions in the \N=8 superconformal Yang-Mills theory in d=3 as well as in the (0,2) superconformal theory in d=6, using their gravity duals with M-theory on $AdS_4\times §^7$ and $AdS_7 \times §^4$ respectively. As a key part of the conje

Gabriela González

We present a calculation of the maximum sensitivity achievable by the LIGO Gravitational wave detector in construction, due to limiting thermal noise of its suspensions. We present a method to calculate thermal noise that allows the prediction of the suspension thermal noise in all its 6 degrees of freedom, from the energy dissipation due to the elasticity o

A. Fasso`, J. Poirier

The FLUKA Monte Carlo program is used to calculate the effects of hadroproduction by primary gamma rays incident upon the earth's atmosphere; for the results presented in this paper, only primary angles at 0 degrees from zenith are considered. The FLUKA code is believed to be quite accurate in reproducing experimental photon hadroproduction data in the 1

Marc Sher

In the most general two-Higgs doublet model (generally referred to as Model III), tree level flavor changing neutral couplings exist. It has been noted that the most natural value for such a coupling is of the order of the geometric mean of the Yukawa couplings of the two fermions. Bounds on those couplings that involve the second and third generations, from

F. Kassubek, C. A. Stafford, Hermann Grabert, Raymond E. Goldstein

A linear stability analysis of metallic nanowires is performed in the free-electron model using quantum chaos techniques. It is found that the classical instability of a long wire under surface tension can be completely suppressed by electronic shell effects, leading to stable cylindrical configurations whose electrical conductance is a magic number 1, 3, 5,

Thomas Dent

We calculate the scalar potential of supersymmetric QCD (in the regime N_f < N_c) coupled to N=1 supergravity with moduli-dependent gauge kinetic function and masses. The gauge dynamics are described by the Taylor-Veneziano-Yankielowicz superpotential for composite effective fields. The potential can be expanded about the ``truncated&#39;&#39; point in the g

Marek Kus, Karol Zyczkowski

Geometric properties of the set of quantum entangled states are investigated. We propose an explicit method to compute the dimension of local orbits for any mixed state of the general K x M problem and characterize the set of effectively different states (which cannot be related by local transformations). Thus we generalize earlier results obtained for the s

Gerald A. Goldin, Vladimir Shtelen

Recent experimental results on slow light heighten interest in nonlinear Maxwell theories. We obtain Galilei covariant equations for electromagnetism by allowing special nonlinearities in the constitutive equations only, keeping Maxwell&#39;s equations unchanged. Combining these with linear or nonlinear Schroedinger equations, e.g. as proposed by Doebner and

A. Cavaliere, V. Vittorini

We derive quantitative predictions of the optical and X-ray luminosity functions (LF) for QSs in the redshift range $z<3$. Based on BH paradigm, we investigate how the accretion is controlled by the surrounding structures, as these grow hierarchically. We argue that for $z < 3$ efficient black hole fueling is triggered by the encounters of a gas-rich host wi

O. Lauscher, M. Reuter, C. Wetterich

Motivated by an analogy with the conformal factor problem in gravitational theories of the $R+R^2$-type we investigate a $d$-dimensional Euclidean field theory containing a complex scalar field with a quartic self interaction and with a nonstandard inverse propagator of the form $-p^2+p^4$. Nonconstant spin-wave configurations minimize the classical action a

Karyn Le Hur

We study two (very) weakly-coupled Hubbard chains in the half-filled case, and especially the situation where the intrachain Mott scale $m$ is much larger than the bare single-electron interchain hopping $t_{\perp}$. First, we find that the divergence of the intrachain Umklapp channel at the Mott transition results in the complete vanishing of the single-ele

F Dolan, H Osborn

The requirements of N=1 superconformal invariance for the correlation functions of chiral superfields are analysed. Complete expressions are found for the three point function for the general spin case and for the four point function for scalar superfields for \sum q_i=3 where q_i is the scale dimension for the i&#39;th superfield and is related to the U(1)

M. N. Chernodub

The interaction of electrically charged particles in a dilute gas of point--like magnetic dipoles is studied. We show that the interaction potential at small distances has a linear piece due to overlap of the dipole clouds gathered near electric sources. At large distances the potential becomes of the Coulomb type with non-perturbatively renormalized charge

M. Lewenstein, D. Bruss, J. I. Cirac, B. Kraus

Quantum mechanics is already 100 years old, but remains alive and full of challenging open problems. On one hand, the problems encountered at the frontiers of modern theoretical physics like Quantum Gravity, String Theories, etc. concern Quantum Theory, and are at the same time related to open problems of modern mathematics. But even within non-relativistic

S. Cheybani, J. Kertesz, M. Schreckenberg

We consider open systems where cars move according to the deterministic Nagel-Schreckenberg rules and with maximum velocity ${v}_{max} > 1$, what is an extension of the Asymmetric Exclusion Process (ASEP). It turns out that the behaviour of the system is dominated by two features: a) the competition between the left and the right boundary b) the development

Kazunori Wakatsuki

We construct a multiple star product method and by using this method, show that integral forms of some star products can be written in terms of the path-integral. This method can be applied to some examples. Especially, the associativity of the skew-symmetrized Berezin star product proposed in \cite{SW}, is recovered in large $N$ limit of the multiple star p

Arvind, N. Mukunda

The phenomenon of quantum entanglement is fundamental to the implementation of quantum computation, and requires at least two qubits for its demonstration. However, both Deutsch algorithm and Grover&#39;s search algorithm for two bits do not use entanglement. We develop a Deutsch-like problem, where we consider all possible binary functions for two bit input

E. Alfinito, G. Vitiello

The mechanism of memory localization in extended domains is described in the framework of the parametric dissipative quantum model of brain. The size of the domains and the capability in memorizing depend on the number of links the system is able to establish with the external world.

E. Alfinito, G. Vitiello

We shortly review the dissipative quantum model of brain and its parametric extension.

Alex Granik, H. Ralph Lewis

An apparent paradox is resolved that concerns the existence of time operators which have been derived for the quantum harmonic oscillator. There is an apparent paradox because, although a time operator is canonically conjugate to the Hamiltonian, it has been asserted that no operator exists that is canonically conjugate to the Hamiltonian. In order to resolv

Victor M. Urbina

Two experiments were made using a microwave generator, which sent a narrow beam, through a metallic plate with horizontal movement. At the other end a horn antenna coupled to a field-strength detector. In linear polarization double cycloids paths were found and in circular polarization spiral paths were found. These experiments suggested that the photon is c

R. Schiavilla

The status of &#34;ab initio&#34; microscopic calculations of the 2H(p,gamma)3He and 3He(p,e+nu_e)4He reactions is reviewed. The methods used to generate accurate nuclear ground- and scattering-state wave functions, and to construct realistic electro-weak transition operators are described. The uncertainties in the theoretical predictions, particularly those

Thomas Peitzmann

Earlier attempts to extract parameters of kinetic freeze-out in Pb+Pb collisions at 158$A$GeV are critically reviewed. Many of these analyses have used approximations which have significant impact on the extracted parameters. Simple estimates are obtained which attempt to avoid the most critical approximations. It is pointed out that constraints based on pio

A. V. Avdeenkov, S. P. Kamerdzhiev

A method based on the consistent use of the Green function formalism has been developed to calculate the distribution of the single-particle strength in odd nuclei with pairing. The method takes into account the quasiparticle-phonon interaction, ground state correlations and a &#34;refinement&#34; of phenomenological single-particle energies and pairing gap

M. Gadella, A. R. Ordoniez

We discuss the validity of a formula concerning a relation between functionals in quantum resonance scattering, which is often used in the current literature.

Max Karoubi, Thierry Lambre

Let A be an arbitrary ring. We introduce a Dennis trace map mod n, from K_1(A;Z/n) to the Hochschild homology group with coefficients HH_1(A;Z/n). If A is the ring of integers in a number field, explicit elements of K_1(A,Z/n) are constructed and the values of their Dennis trace mod n are computed. If F is a quadratic field, we obtain this way non trivial el

Daqing Wan

By restricting the variables running over various (possibly different) subfields, we introduce the notion of a partial zeta function. We prove that the partial zeta function is rational in an interesting case, generalizing Dwork&#39;s well known rationality theorem. In general, the partial zeta function is probably not rational. But a theorem of Faltings say

Daqing Wan

This is an expository paper which gives a simple arithmetic introduction to the conjectures of Weil and Dwork concerning zeta functions of algebraic varieties over finite fields. A number of further open questions are raised.

Donu Arapura, Sviatoslav Archava

In this short note, we determine the Kodaira dimension and some of the plurigenera of (a desingularization of) a symmetric power of a smooth projective variety. We use it to obtain bounds on the genus of curve passing through a fixed number of general points.

Leonard M. Smiley

The exponential generating functions of {n^(n+m)} for arbitrary integer m are expressed as rational functions of the e.g.f. of {n^(n-1)} [the tree function] and then of the e.g.f. of {n^n} [the endofunction function]. The coefficients in these rational functions include 2nd-order Eulerian numbers (a result of L. Carlitz), 2nd-order Stirling numbers, and Stir

Yongcun Gao, Haisheng Li

It is proved that for a vector space W, any set of parafermion-like vertex operators on W in a certain canonical way generates a generalized vertex algebra in the sense of [DL2] with W as a natural module. This result generalizes a result of [Li2]. As an application, generalized vertex algebras are constructed from Lepowsky-Wilson&#39;s Z-algebras of any non

Simone Secchi

We prove the existence of multiple closed geodesics on non-compact cylindrica manifolds.

Toshiyuki Abe

We completely determine the fusion rules for the vertex operator algebra $V_L^+$ for a rank one even lattice $L$.

Palle E. T. Jorgensen

We show that compactly supported wavelets in L^2(R) of scale N may be effectively parameterized with a finite set of spin vectors in C^N, and conversely that every set of spin vectors corresponds to a wavelet. The characterization is given in terms of irreducible representations of orthogonality relations defined from multiresolution wavelet filters.

Zinovy Reichstein, Boris Youssin

We prove an equivariant version of Hironaka&#39;s theorem on elimination of points of indeterminacy. Our arguments rely on canonical resolution of singularities.

Iosif Bena, Aleksey Nudelman

We investigate the oblique vacua in the perturbed 2+1 dimensional gauge theory living on D2 branes. The string theory dual of these vacua is expected to correspond to polarizations of the D2 branes into NS5 branes with D4 brane charge. We perturb the gauge theory by adding fermions masses. In the nonsupersymmetric case, we also consider the effect of slight

J. Berges, J. Cox

We study the time evolution of correlation functions in closed quantum systems for nonequilibrium ensembles of initial conditions. For a scalar quantum field theory we show that generic time-reversal invariant evolutions approach equilibrium at large times. The calculation provides a first principles justification of Boltzmann's conjecture that the large-tim

V. N. Gribov

This is a classical paper by Vladimir Gribov (1930-97) which has influenced the understanding of high energy hadron collisions and deep inelastic scattering for several decades, and is still important today. Gribov&#39;s main assumption - that partons have limited transverse momenta - was later proved to be satisfied in QCD, modulo logarithmic corrections. H

Andre de Gouvea

In this paper, I address the oscillation probability of O(GeV) neutrinos of all active flavours produced inside the Sun and detected at the Earth. Flavours other than electron-type neutrinos may be produced, for example, by the annihilation of WIMPs which may be trapped inside the Sun. In the GeV energy regime, matter effects are important both for the ``1-3

Dmitri Antonov

The bilocal electric field strength correlators in Abelian-projected SU(2)- and SU(3)-theories are derived with accounting for the contributions to these quantities brought about by the virtual vortex loops, built out of the dual Nielsen-Olesen strings. Owing to the screening of magnetic charge of the dual vector bosons in the gas of such loops, these bosons

M. Garcia Perez, T. G. Kovacs, P. van Baal

Overlapping instantons have an action density profile that significantly deviates from the simple addition of the density profiles of single instantons. This turns out to have important consequences for identifying the proper instanton content of a given configuration. Most dramatic is the case where the instantons are parallel in group space, leading to the

W. L. van Neerven, A. Vogt

We study the next-to-next-to-leading order (NNLO) evolution of flavour singlet parton densities and structure functions in massless perturbative QCD. Present information on the corresponding three-loop splitting functions is used to derive parametrizations of these quantities, including Bjorken-x dependent estimates of their residual uncertainties. Compact e

D. Schildknecht

We briefly summarize the equivalence of off-diagonal generalized vector dominance and the colour-dipole approach to deep-inelastic scattering (DIS) in the diffraction region of values of $x \simeq Q^2/W^2 << 1$.

Marc Bertini, Leif Lonnblad, Torbjorn Sjostrand

This document describes the first proof-of-concept version of the Pythia7 program. Pythia7 is a complete re-write of the Pythia program in C++. It is mainly intended to be a replacement for the `Lund&#39; family of event generators, but is also a toolkit with a structure suitable for implementing any event generator model. In this document, the structure of

P. Kocian

It is shown that the definition of the photon field in the broken-symmetry phase of the electroweak theory proposed recently by O.T(ornkvist is equivalent to that proposed previously by Vlasov et al.

Ulrich Heinz, Pierre Scotto, Qing-Hui Zhang

Multi-boson symmetrization effects on two-particle Bose-Einstein interferometry are studied for ensembles with arbitrary multiplicity distributions. This generalizes the previously studied case of a Poissonian input multiplicity distribution. In the general case we find interesting residual correlations which require a modified framework for extracting infor

J. -M. Frere, M. V. Libanov, S. V. Troitsky

In realistic supersymmetric models, very small hard supersymmetry breaking terms generally appear. Some of them violate baryon and/or lepton number. We discuss their possible applications to proton decay and generation of neutrino masses.

R. Brock, D. Casey, J. Huston, J. Kalk

We describe preliminary results from an effort to quantify the uncertainties in parton distribution functions and the resulting uncertainties in predicted physical quantities. The production cross section of the $W$ boson is given as a first example. Constraints due to the full data sets of the CTEQ global analysis are used in this study. Two complementary a

Ze-sen Yang, Xianhui Li, Weizhen Deng, Xiaolin Chen

This paper has been withdrawn by the authors due to some errors.

The SLD Collaboration

We have made the first direct measurement of the parity-violating coupling of the Z^0 boson to the strange quark, A_s, using ~550,000 e^+e^- ->Z^0->hadrons events produced with a polarized electron beam and recorded by the SLD experiment. Z^0 -> s-sbar events were tagged by the absence of B or D hadrons and the presence in each hemisphere of a high-momentum

CLEO Collaboration, M. Artuso

We report on the observation of B->D{*}pi+pi-pi-pio decays. The branching ratios for D*+ and D*o are (1.72+/-0.14+/-0.24)% and (1.80+/-0.24+/-0.25)%, respectively. Each final state has a D{*} omega pi- component, with branching ratios (0.29+/-0.03+/-0.04)% and (0.45+/-0.10+/-0.07)% for the D*+ and D*o modes, respectively. We also observe B->D omega pi- decay

H1 Collaboration, C. Adloff

The inclusive cross section for the photoproduction of neutral pions has been measured as a function of the transverse momentum, rapidity, and Feynman x of the pizero mesons at an average photon--proton centre-of-mass energy of 208 GeV and for photon virtualities below Q^2=0.01 GeV^2. The pizero measurement extends the range covered by previous charged parti

F. Gianotti, M. Pepe-Altarelli

A large number of precision measurements will be possible with the ATLAS and CMS experiments at the CERN Large Hadron Collider (LHC). Examples from W physics, Drell-Yan production of lepton pairs, Triple-Gauge Couplings,top physics, Higgs and Supersymmetry are discussed.

F. Brandi, M. Bregant, G. Cantatore, F. Della Valle

The PVLAS collaboration is at present running, at the Laboratori Nazionali di Legnaro of I.N.F.N., Padova, Italy, a very sensitive optical ellipsometer capable of measuring the small rotations or ellipticities which can be acquired by a linearly polarized laser beam propagating in vacuum through a transverse magnetic feld (vacuum magnetic birefringence). The

Daniel Sudarsky

In this comment we point out some problems with the approach used in the paper &#34;Scalar fields as dark matter in spiral galaxies&#34; in the attempt to explain the flatness of the rotation curves of galaxies.

Alexander Yu. Dobin, Wenhui Duan, Renata M. Wentzcovitch

We have successfully calculated the electronic and structural properties of chromia (Cr_2O_3) in the Local Spin Density Approximation (LSDA). We predict a transformation from the corundum to the Rh_2O_3(II) structure around 15 GPa in the anti-ferromagnetic (AFM) phase as well as in the paramagnetic (PM) insulating state which occurs above the Neel temperatur

S. G. Bompadre, C. Biagini, D. Maslov, A. F. Hebard

Magnetotransport has been investigated in high purity bismuth crystals in static magnetic fields as high as 20 T and temperatures as low as 25 mK. This high B/T ratio permits observation of pronounced Shubnikov-de Haas oscillations over a wide field range and up to fields where most of the carriers are in the lowest Landau level. For transport currents in th

N. Priezjev, Robert A. Pelcovits

We report the results of Monte Carlo simulations of the Lebwohl--Lasher model of nematic liquid crystals confined to cylindrical cavities with homeotropic anchoring. We show that the ratio of the bulk to surface couplings is not in general equal to the corresponding parameter K/W used in elastic theory (where K is the Frank elastic constant in the one consta

Thomas L. Beck

This review discusses progress in efficient solvers which have as their foundation a representation in real space, either through finite-difference or finite-element formulations. The relationship of real-space approaches to linear-scaling electrostatics and electronic structure methods is first discussed. Then the basic aspects of real-space representations

E. M. F. Curado, M. A. Rego-Monteiro

We show that the infinite-dimensional representation of the recently introduced Logistic algebra can be interpreted as a non-trivial generalization of the Heisenberg or oscillator algebra. This allow us to construct a quantum Hamiltonian having the energy spectrum given by the logistic map. We analyze the Hamiltonian of a solid whose collective modes of vibr

Satya N. Majumdar, P. L. Krapivsky

We investigate the statistics of extremal path(s) (both the shortest and the longest) from the root to the bottom of a Cayley tree. The lengths of the edges are assumed to be independent identically distributed random variables drawn from a distribution ρ(l). Besides, the number of branches from any node is also random. Exact results are derived for arbitrar

A. Widom, M. S. Tomassone, Y. N. Srivastava, M. Hannout

Adsorbed noble gas atoms donate (on the average) a fraction of an electronic charge to the substrate metal. The effect has been experimentally observed as an adsorptive change in the electronic work function. The connection between the effective net atomic charge and the binding energy of the atom to the metal is theoretically explored.

Erik S. Sorensen

Using the mapping of the partition function of the two-dimensional Ising model onto a pfaffian we evaluate the domain wall free energy difference for the pure and disordered Ising model close to the pure fixed point. Using this method very large lattices can be studied exactly and we confirm that disorder even including frustrating interactions indeed are ir

Davide Stelitano, Daniel H. Rothman

We study the dynamics of elastic interfaces-membranes-immersed in thermally excited fluids. The work contains three components: the development of a numerical method, a purely theoretical approach, and numerical simulation. In developing a numerical method, we first discuss the dynamical coupling between the interface and the surrounding fluids. An argument

Z. Ropka, R. J. Radwanski

We argue that the Jahn-Teller theorem, if applied to 3d-ion compounds, has to be considered in the orbital+spin space. It is despite of the weakness of the intraatomic spin-orbit coupling.

E. Hernandez, P. Ordejon, I. Boustani, A. Rubio

In this paper we report a theoretical study of the effects of the presence of boron in growing carbon nanotubes. We employ a well established Tight Binding model to describe the interactions responsible for the energetics of these systems, combined with the Molecular Dynamics simulation technique and Structural Relaxation calculations. We find, in agreement

A. Díaz-Sánchez, A. Möbius, M. Ortuño, A. Neklioudov

We present a numerical method for the investigation of non-ergodic effects in the Coulomb glass. For that, an almost complete set of low-energy many-particle states is obtained by a new algorithm. The dynamics of the sample is mapped to the graph formed by the relevant transitions between these states, that means by transitions with rates larger than the inv

Paolo De Los Rios, Oscar Pla

Repetitions within a given genealogical tree provides some information about the degree of consanguineity of a population. They can be analyzed with techniques usually employed in statistical physics when dealing with fixed point transformations. In particular we show that the tree features strongly depend on the fractions of males and females in the populat

K. Shizuya

A numerical study is made of current distribution in small Hall bars with disorder. It is observed, in particular, that in the Hall-plateau regime the Hall current tends to concentrate near the sample edges while it diminishes on average in the sample interior as a consequence of localization. Also reported is another numerical experiment on a related, but r

E. E. Takhtamirov, V. A. Volkov

In ultra-clean 2D electron systems on (001) GaAs/AlGaAs upon filling high Landau levels, it was recently observed a new class of collective states, which can be related to the spontaneous formation of a charge density wave (``striped phase&#39;&#39;). We address to the following unsolved problem: what is the reason for stripe pinning along the crystallograph

A. Bednorz, M. Napiorkowski

We propose a method to describe the short-distance behavior of an interface fluctuating in the presence of the wedge-shaped substrate near the critical filling transition. Two different length scales determined by the average height of the interface at the wedge center can be identified. On one length scale the one-dimensional approximation of Parry et al. \

S. Cheybani, J. Kertesz, M. Schreckenberg

We study the phases of the Nagel-Schreckenberg traffic model with open boundary conditions as a function of the randomization probability p > 0 and the maximum velocity ${v}_{max} > 1$. Due to the existence of &#34;buffer sites&#34; which enhance the free flow region, the behaviour is much richer than that of the related asymmetric exclusion process (ASEP, {

S. Pilgram, W. Belzig, C. Bruder

We investigate one aspect of the proximity effect, viz., the local density of states of a superconductor-normal metal sandwich. In contrast to earlier work, we allow for the presence of an arbitrary concentration of impurities in the structure. The superconductor induces a gap in the normal metal spectrum that is proportional to the inverse of the elastic me

Ross H. McKenzie, Perez Moses

The interlayer magnetoresistance of a quasi-one-dimensional Fermi liquid is considered for the case of a magnetic field that is rotated within the plane perpendicular to the most-conducting direction. Within semi-classical transport theory dips in the magnetoresistance occur at integer amgic angles only when the electronic dispersion parallel to the chains i

R. G. Mints, Ilya Papiashvili

Grain boundaries in YBa$_2$Cu$_3$O$_{7-x}$ superconducting films are considered as Josephson junctions with a critical current density $j_c(x)$ alternating along the junction. A self-generated magnetic flux is treated both analytically and numerically for an almost periodic distribution of $j_c(x)$. We obtained a magnetic flux-pattern similar to the one whic

Kazuhiko Kuroki, Ryotaro Arita, Hideo Aoki

By examining how the spin- and/or charge-fluctuation exchange can contribute to pairing instabilities, we propose that a spin-triplet f-wave-like pairing with a d-vector perpendicular to the b-axis may be realized in (TMTSF)_2 PF_6 due to (i) a quasi-one-dimensional Fermi surface, (ii) a coexistence of 2k_F charge fluctuations and spin fluctuations, and (iii

Kwan-tai Leung

We present an approximate and heuristic scheme for the derivation of continuum kinetic equations from microscopic dynamics for stochastic, interacting systems. The method consists of a mean-field type, decoupled approximation of the master equation followed by the `naive&#39; continuum limit. The Ising model and driven diffusive systems are used as illustrat

Marcelo Alvarez, Paul R. Shapiro, Hugo Martel

Adaptive SPH and N-body simulations were carried out to study the effect of gasdynamics on the structure of dark matter halos that result from the gravitational instability and fragmentation of cosmological pancakes. Such halos resemble those formed in a hierarchically clustering CDM universe and serve as a test-bed model for studying halo dynamics. With no

Azita Valinia, Vincent Tatischeff, Keith Arnaud, Ken Ebisawa

We propose a mechanism for the origin of the Galactic ridge X-ray background that naturally explains the properties of the Fe K line, specifically the detection of the centroid line energy below 6.7 keV and the apparent broadness of the line. Motivated by recent evidence of nonthermal components in the spectrum of the Galactic X-ray/gamma-ray background, we

T. J. Galama, M. Bremer, F. Bertoldi, K. M. Menten

The millimeter wavelength emission from GRB 991208 is the second brightest ever detected, yielding a unique data set. We present here well-sampled spectra and light curves over more than two decades in frequency for a two-week period. This data set has allowed us for the first time to trace the evolution of the characteristic synchrotron self-absorption freq

S. C. Chapman, P. McCarthy, S. E. Persson

Galaxy clusters at high redshift present a superb opportunity to study galaxy evolution, with large galaxy samples at fixed distances. Several lines of evidence point towards large formation redshifts and passive evolution for cluster ellipticals. At redshifts larger than z~0.8, this picture rests on data from only a handful of rich clusters. We have observe

Renee C. Kraan-Korteweg

Dust and stars in the plane of the Milky Way create a &#34;Zone of Avoidance&#34; in the extragalactic sky. Galaxies are distributed in gigantic labyrinth formations, filaments and great walls with occasional dense clusters. They can be traced all over the sky, except where the dust within our own galaxy becomes too thick - leaving about 25% of the extragala

J A Sellwood, N W Evans

We confirm that a high rate of shear at the center is able to stabilize an entire stellar disk against bar-forming (m=2) modes, irrespective of the dark halo density. Our simulations of unstable power-law disks also yield the growth rate and pattern speed of the dominant lop-sided (m=1) mode in close agreement with that predicted by linear theory in our clea

Christophe Mayen, Genevieve Soucail

We present a detailed study of the depletion effect (the radial manifestation of the magnification bias) in the cluster MS1008-1224. Following our results concerning the simulations of depletion curves (see Mayen and Soucail, 2000 (astro-ph/0003332) for a complete description of the code), we propose to constrain the mass profile of the cluster and the main

C. Tanihata, T. Takahashi, J. Kataoka, G. M. Madejski

We report the variable X-ray emission from BL Lacertae detected in the ASCA ToO observation conducted during the EGRET and RXTE pointings, coincident with the 1997 July outburst. The source showed a historically high state of X-ray, optical, and gamma-ray emission, with its 2-10 keV flux peaking at ~3.3 E-11 erg/cm2/s. This is more than 3 times higher than t

Angeles I. Diaz, Marcelo Castellanos, Elena Terlevich, Maria L. Garcia-Vargas

We present long-slit observations in the optical and near infrared of eight HII regions in the spiral galaxy NGC 4258. Six of the observed regions are located in the SE inner spiral arms and the other two are isolated in the northern outer arms. A detailed analysis of the physical conditions of the gas has been performed. For two of the regions, an electron

Peter Watts, Andrew Taylor

We present a new analytic calculation for the redshift-space evolution of the 1-point galaxy Probability Distribution Function (PDF). The nonlinear evolution of the matter density field is treated by second-order Eulerian perturbation theory and transformed to the galaxy density field via a second-order local biasing scheme. We then transform the galaxy dens

P. Royer, J. Manfroid, E. Gosset, J. -M. Vreux

This paper addresses the question of the observations to be performed with the Optical Monitor (OM) of the X-ray Multi-Mirror Satellite (XMM) under several aspects. First, we discuss XMM-OM&#39;s photometric system and its colour transformations towards the standard UBV system. Second, we establish a set of procedures to determine the temperature and the amo

Ryoichi Nishi, Motomichi Tashiro

We investigate the process of self-regulated star formation via photodissociation of hydrogen molecules in low metallicity clouds. We evaluate the influence region&#39;s scale of a massive star in low metallicity gas clouds whose temperatures are between 100 and 10000 Kelvin. A single O star can photodissociate hydrogen molecules in the whole of the host clo