January 2002 arXiv papers — page 3

Volker Enss, Vadim Kostrykin, Robert Schrader

Quantum mechanical scattering theory is studied for time-dependent Schroedinger operators, in particular for particles in a rotating potential. Under various assumptions about the decay rate at infinity we show uniform boundedness in time for the kinetic energy of scattering states, existence and completeness of wave operators, and existence of a conserved q

Jesper L. Jacobsen, Paul Zinn-Justin

We propose a new method to enumerate alternating knots using a transfer matrix approach. We apply it to count numerically various objects, including prime alternating tangles with two connected components, up to order 18--22, and comment on the large-order behavior in connection with one of the authors' conjecture.

Atsushi Katsuda, Yaroslav Kurylev, Matti Lassas

We consider stability and approximate reconstruction of Riemannian manifold when the finite number of eigenvalues of the Laplace-Beltrami operator and the boundary values of the corresponding eigenfunctions are given. The reconstruction can be done in stable way when manifold is a priori known to satisfy natural geometrical conditions related to curvature an

Darryl Whitlow

Two finite volume methods are derived and applied to the solution of problems of incompressible flow. In particular, external inviscid flows and boundary-layer flows are examined. The firstmethod analyzed is a cell-centered finite volume scheme. It is shown to be formally first order accurate on equilateral triangles and used to calculate inviscid flow over

Mikhail Khovanov

Cohomology theory of links, introduced by the author, is combinatorial. Dror Bar-Natan recently wrote a program that found ranks of cohomology groups of all prime knots with up to 11 crossings. His surprising experimental data is discussed in this note.

Steven Lillywhite

We prove a result concerning formality of the pull-back of a fibration. Our approach is to use bar complexes in the category of commutative differential graded algebras. As an application, we generalize an old result of Baum and Smith.

Samuel S. Holland

We study the ring generated over a field of characteristic 0 by noncommuting indeterminates {x_1,x_2,...,x_n} subject only to the relations x_iσ_k=σ_k x_i, for i,k=1,2,...,n, and their consequences, where σ_k =σ_k(x_1,x_2,...,x_n) is the k-th elementary polynomial in the noncommuting variables x_i. We assume n\geq 3 throughout.

P. Auscher, E. Russ

Let $Ω$ be a strongly Lipschitz domain of $\reel^n$. Consider an elliptic second order divergence operator $L$ (including a boundary condition on $\partialΩ$) and define a Hardy space by imposing the non-tangential maximal function of the extension of a function $f$ via the Poisson semigroup for $L$ to be in$L^1$. Under suitable assumptions on $L$, we identi

Jobst Heitzig

Different types of two- and three-dimensional representations of a finite metric space are studied that focus on the accurate representation of the linear order among the distances rather than their actual values. Lower and upper bounds for representability probabilities are produced by experiments including random generation, a rubber-band algorithm for acc

Carlo Mantegazza, Andrea Carlo Mennucci

The paper is concerned with the properties of the distance function from a closed subset of a Riemannian manifold, with particular attention to the set of singularities.

Marco Kuehnel

We prove the rationality of the Kähler cone and the positivity of $c_2(X)$, if $X$ is a Calabi-Yau-threefold with $ρ(X)=2$ and has an embedding into a ${\bb P}^n$-bundle over ${\bb P}^m$ in the cases $(n,m)=(1,3),(3,1)$. The case $(n,m)=(2,2)$ has been done in the first part of this paper. Moreover, if $(n,m)=(3,1)$, we describe the 'other' contracti

Gianni Arioli

This paper concerns the restricted 3-body problem. By applying topological methods we give a computer assisted proof of the existence of some classes of periodic orbits, the existence of symbolic dynamics and we give a rigorous lower estimate for the topological entropy.

Fedor Duzhin

A lower bound for the number of 3-periodical billiard trajectories in a manifold embedded in Euclidean space is obtained.

Fabrizio M. E. Catanese

The Leit-Faden of the article (which is partially a survey) is a negative answer to the question whether, for a compact complex manifold which is a $K(π, 1)$ the diffeomorphism type determines the deformation type. We show that a deformation in the large of complex tori is again a complex torus, and then that the same holds for products of a torus with a cur

Massimo Porrati, Andrei Starinets

We consider Einstein gravity coupled to a CFT made of a single free conformal scalar in 4-d Anti de Sitter space. This simple case is rich enough to explain an unexpected gravitational Higgs phenomenon that has no flat-space counterpart, yet simple enough that many calculations can be carried on exactly. Specifically, in this paper we compute the graviton se

B. Pioline

Just as non-commutative gauge theories arise from quantising open strings in a large magnetic field, non-Abelian two-form gauge theories may conceivably be constructed by quantising open membranes in a large three-form magnetic background. We make some observations that arise in following this strategy, with an emphasis on the relation to the quantisation of

Kirill A. Kazakov

The question of general covariance in quantum gravity is considered in the first post-Newtonian approximation. Transformation properties of observable quantities under deformations of a reference frame, induced by variations of the gauge conditions fixing general invariance, are determined. It is found that the one-loop contributions violate the principle of

Horacio E. Camblong, Carlos R. Ordonez

A path-integral approach for the computation of quantum-mechanical propagators and energy Green's functions is presented. Its effectiveness is demonstrated through its application to singular interactions, with particular emphasis on the inverse square potential--possibly combined with a delta-function interaction. The emergence of these singular potenti

Kimmo Kainulainen, Tomislav Prokopec, Michael G. Schmidt, Steffen Weinstock

We review and extend to include the gauge fields our derivation of the semiclassical limit of the collisionless quantum transport equations for the fermions in presence of a CP-violating bubble wall at a first order electroweak phase transition. We show how the (gradient correction modified) Lorenz-force appears both in the Schwinger-Keldysh approach and in

S. R. Slabospitsky, L. Sonnenschein

This is the manual of the specialized event generator TopReX 3.25. The generator provides the simulation of several important processes in pp and p pbar collisions, not implemented in PYTHIA (yet). Some of these processes include t-quarks whose spin polarizations are taken into account in the subsequent decay of the t-quarks. Several non-SM top quark decay c

G. L. Fogli, E. Lisi, A. Marrone, D. Montanino

We review the status of several phenomenological topics of current interest in neutrino oscillations: (i) Solar neutrino oscillations after the first Sudbury Neutrino Observatory measurements, including both model-independent and model-dependent results; (ii) Dominant nu_mu-->nu_tau oscillations of atmospheric and K2K neutrinos, and possible subdominant osci

N. Beisert, B. Borasoy

The dominant decay mode of the eta-prime, eta-prime -> eta pi pi, is investigated within the framework of infrared regularized U(3) chiral perturbation theory up to fourth chiral order and including one-loop corrections. We find reasonable agreement with experimental data and observe convergence of the chiral series.

W. Detmold, W. Melnitchouk, A. W. Thomas

We examine the extraction of moments of parton distributions from lattice data, focusing in particular on the chiral extrapolation as a function of the quark mass. Inclusion of the correct chiral behavior of the spin-averaged isovector distribution resolves a long-standing discrepancy between the lattice moments and experiment. We extract the x-dependence of

W. Porod, W. Majerotto

We study lepton flavor violating signals at a future e+ e- linear collider within the general MSSM, allowing for the most general flavor structure. We demonstrate that there is a large region in parameter space with large signals, while being consistent with present experimental bounds on rare lepton decays such as mu -> e gamma. In our analysis, we include

A. Belkov, S. Shulga

We present the SIMUB package developed at Dubna for MC generation of B meson production and decays. The starting version of the package includes lepton modes of B decays, in particular, semileptonic decays B->D^*lνand "golden" mode B->J/ψ(μμ)ϕ(KK) with taking into account all theoretical refinements including B^0-Bbar^0 oscillations and angular corre

S. Frixione, P. Nason

We present predictions for single inclusive distributions of charmed mesons, relevant to the HERA experiments. Our results are based upon a computation that correctly incorporates mass effects up to the next-to-leading order level, and the resummation of transverse momentum logarithms up to next-to-leading-logarithmic level. We apply the same acceptance cuts

Jean El Bachir Mendy, Jan Govaerts

Given the eventuality of neutrino and muon factories in the foreseeable future, all possible 2-to-2 processes involving two neutrinos, whether Dirac or Majorana ones, and two charged fermions are considered on the basis of the most general Lorentz invariant four-fermion effective interaction possible, in the limit of massless particles. Such a parametrizatio

Joanna Kiryluk

The STAR collaboration aims to study polarized proton-proton collisions at RHIC. The emphasis of the spin run this year is on transverse single spin asymmetries. Beyond 2001, we aim to determine directly and precisely the gluon polarization, as well as the polarizations of the u, $\bar{u}$, d and $\bar{d}$ quarks in the proton by measuring in addition longit

Kimmo Kainulainen, Tomislav Prokopec, Michael G. Schmidt, Steffen Weinstock

We consider the dynamics of fermions with a spatially varying mass which couple to bosons through a Yukawa interaction term and perform a consistent weak coupling truncation of the relevant kinetic equations. We then use a gradient expansion and derive the CP-violating source in the collision term for fermions which appears at first order in gradients. The c

K. K. Gan

We present new results on the optical link for the pixel detector of the ATLAS experiment. An optical package of novel design has been developed for the opto-link. The design is based on a simple connector-type concept and is made of radiation-hard material. The receiver (DORIC) and transmitter (VDC) chips have been designed. The prototype results using the

Z. Zhao, G. Eigen, G. Burdman, W. Marciano

We report on the status and plans of experiments now running or proposed for electron-positron colliders at energies between the $ϕ$ and the Z. The $e^{+}e^{-}$ B and charm factories we considered were PEP-II/BABAR, KEKB/Belle, superKEK, SuperBABAR, and CESR-c/CLEO-c. We reviewed the programs at the $ϕ$ factory at Frascati and the proposed PEP-N facility at

Thomas Kress

Particle correlations are extensively studied to obtain information about the dynamics of hadron production. From 1989 to 2000 the four LEP collaborations recorded more than 16 million hadronic Z0 decays and several thousand W+W- events. In Z0 decays, two-particle correlations were analysed in detail to study Bose-Einstein and Fermi-Dirac correlations for va

D. E. Diaz, J. Stephany

We examine the excitation of a uniformly accelerated DeWitt-Takagi detector coupled quadratically to a Majorana-Dirac field. We obtain the transition probability from the ground state of the detector and the vacuum state of the field to an excited state with the emission of a Minkowski pair of quanta, in terms of elementary processes of absorption and scatte

Christoph Schmid

The axes of gyroscopes experimentally define non-rotating frames. But what physical cause governs the time-evolution of gyroscope axes? Starting from an unperturbed, spatially flat FRW cosmology, we consider cosmological vorticity perturbations (i.e. vector perturbations, rotational perturbations) at the linear level. We ask: Will cosmological rotational per

W. B. Bonnor

I obtain an exact, axially symmetric, stationary solution of Einstein's equations for two massless spinning particles. The term representing the spin-spin interaction agrees with recently published approximate work. The spin-spin force appears to be proportional to the inverse fourth power of the coordinate distance between the particles.

Jorge Castineiras, Luis C. B. Crispino, George E. A. Matsas, Daniel A. T. Vanzella

We analyze free elementary particles with rest mass $m$ and total energy $E < m c^2$ in the Rindler wedge, outside Reissner-Nordstrom black holes and in the spacetime of relativistic (and non-relativistic) stars, and use Unruh-DeWitt-like detectors to calculate the associated particle detection rate in each case. The (mean) particle position is identified wi

Raimondas Lencevicius, Edu Metz, Alexander Ran

The validation of modern software systems incorporates both functional and quality requirements. This paper proposes a validation approach for software quality requirement - its power consumption. This approach validates whether the software produces the desired results with a minimum expenditure of energy. We present energy requirements and an approach for

David Fulker, Greg Janee

We describe work leading toward specification of a technical architecture for the National Science, Mathematics, Engineering, and Technology Education Digital Library (NSDL). This includes a technical scope and a functional model, with some elaboration on the particularly rich set of library services that NSDL is expected eventually to encompass.

S. Martinez, F. Pennini, C. Tessone, A. Plastino

We give an exact information-theory treatment of the $n$-dimensional black-body radiation process in a non-extensive scenario. We develop a $q$ generalization of the laws of i) Stefan Boltzmann, ii) Planck, and iii) Wien, and show that conventional, canonical results are obtained at temperatures above $1 K$. Classical relationships between radiation, pressur

D. Y. Vodolazov, F. M. Peeters

The stable and metastable states of different configurations of a loop in the form of an eight is studied in the presence of a magnetic field. We find that for certain configurations the current is equal to zero for any value of the magnetic field leading to a magnetic field independent superconducting state. The state with fixed phase circulation becomes un

D. M. Jezek, P. Capuzzi, H. M. Cataldo

We develop a three-dimensional analysis of the phase separation of two-species Bose-Einstein condensates in the presence of vorticity within the Thomas-Fermi approximation. We find different segregation features according to whether the more repulsive component is in a vortex or in a vortex-free state. An application of this study is aimed at describing syst

Dieter W. Heermann, Claudette E. Cordeiro

In mean-field theory, i.e. infinite-range interactions, the transition between metastable and unstable states of a thermodynamic system is sharp. The metastable and the unstable states are separated by a spinodal curve. For systems with short-range interaction the transition between metastable and unstable states has been thought of as gradual. We show evide

R. Claessen, M. Sing, U. Schwingenschloegl, P. Blaha

The electronic structure of the quasi-one-dimensional organic conductor TTF-TCNQ is studied by angle-resolved photoelectron spectroscopy (ARPES). The experimental spectra reveal significant discrepancies to band theory. We demonstrate that the measured dispersions can be consistently mapped onto the one-dimensional Hubbard model at finite doping. This interp

Miguel A. Ramos, Cesar Talon, Sebastian Vieira

We review in this work specific-heat experiments, that we have conducted on different hydrogen-bonded glasses during last years. Specifically, we have measured the low-temperature specific heat Cp for a set of glassy alcohols: normal and fully-deuterated ethanol, 1- and 2- propanol, and glycerol. Ethanol exhibits a very interesting polymorphism presenting th

Susanna C. Manrubia, Damian H. Zanette

Surnames and nonrecombining alleles are inherited from a single parent in a highly similar way. A simple birth-death model with mutations can accurately describe this process. Exponentially growing and constant populations are investigated, and we study how different compositions of the founder populations can be observed in present-day diversity distributio

D. M. Edwards

The physics of ferromagnetic doped manganites, such as \chem{La_{1-x}Ca_xMnO_3} with $x\approx0.2$--0.4, is reviewed. The concept of double exchange is discussed within the general framework of itinerant electron magnetism. The new feature in this context is the coupling of electrons to local phonon modes. Emphasis is placed on the quantum nature of the phon

O. Rodriguez de la Fuente, J. A. Zimmerman, M. A. Gonzalez, J. de la Figuera

We present a combined study by Scanning Tunneling Microscopy and atomistic simulations of the emission of dissociated dislocation loops by nanoindentation on a (001) fcc surface. The latter consist of two stacking-fault ribbons bounded by Shockley partials and a stair-rod dislocation. These dissociated loops, which intersect the surface, are shown to origina

L. Capogna, E. M. Forgan, S. M. Hayden, A. Wildes

We report the first observation of two-dimensional incommensurate magnetic fluctuations in the layered metallic perovskite Sr3Ru2O7. The wavevectors where the magnetic fluctuations are strongest are different from those observed in the superconducting single layer ruthenate Sr2RuO4 and appear to be determined by Fermi surface nesting. No antiferromagnetic or

Marco Pretti

In this paper we consider the variational approach to cactus trees (Husimi trees) and the more common recursive approach, that are in principle equivalent for finite systems. We discuss in detail the conditions under which the two methods are equivalent also in the analysis of infinite (self-similar) cactus trees, usually investigated to the purpose of appro

M. Combescot, O. Betbeder-Matibet

Excitons, being made of two fermions, may appear from far as bosons. Their close-to-boson character is however quite tricky to handle properly. Using our commutation technique especially designed to deal with interacting close-to-boson particles, we here calculate the exact expansion in Coulomb interaction of theexciton-exciton correlations, and show that a

X. Leyronas, M. Combescot

From a careful study of the transcendental equations fulfilled by the bound state energies of a free particle in a quantum well, cylindrical wire or spherical dot with finite potential barrier, we have derived analytical expressions of these energies which reproduce impressively well the numerical solutions of the corresponding transcendental equations for a

V. F. Pisarenko, D. Sornette

We present a quantitative statistical test for the presence of a crossover c0 in the Gutenberg-Richter distribution of earthquake seismic moments, separating the usual power law regime for seismic moments less than c0 from another faster decaying regime beyond c0. Our method is based on the transformation of the ordered sample of seismic moments into a serie

E. A. Yuzbashyan, B. L. Altshuler, B. S. Shastry

The paper is devoted to the connection between integrability of a finite quantum system and degeneracies of its energy levels. In particular, we analyze in detail the energy spectra of finite Hubbard chains. Heilmann and Lieb demonstrated that in these systems there are crossings of levels of the same parameter independent symmetry. We show that this apparen

T. Schenkel, J. P. Holder, J. W. McDonald, J. Meijer

Several solid state quantum computer schemes are based on the manipulation of electron and nuclear spins of single donor atoms in a solid matrix. The fabrication of qubit arrays requires the placement of individual atoms with nanometer precision and high efficieny. In this article we describe first results from low dose, low energy implantations and our deve

W. J. Padilla, D. N. Basov, D. Mandrus

Infrared reflectance measurements were made on the single crystal pyrochlore Cd$_{2}$Os$_{2}$O$_{7}$ in order to examine the transformations of the electronic structure and crystal lattice across the boundary of the metal insulator transition at $T_{MIT}=226K$. All predicted IR active phonons are observed in the conductivity over all temperatures and the osc

Wei Bao, S. F. Trevino, J. W. Lynn, P. G. Pagliuso

The effect of hydrostatic pressure on the incommensurate antiferromagnetic structure of CeRhIn5 is investigated with neutron diffraction using a He pressure cell. At 3.8 kbar, the staggered magnetic moment is 0.37(4) Bohr magneton per Ce at 1.6 K, which is the same as the ambient-pressure value. The Neel temperature T_N=3.8(1) K is also the same as the ambie

Henning Arendt Knudsen, Alex Hansen

We study average flow properties in porous media using a two-dimensional network simulator. It models the dynamics of two-phase immiscible bulk flow where film flow can be neglected. The boundary conditions are biperiodic which provide a means of studying steady state flow where complex bubble dynamics dominate the flow picture. We find fractional flow curve

Sumithra Sankararaman, R. Shankar

We investigate the existence of spiral ordering in the planar spin orientation of skyrmions localised on a face centered rectangular lattice (FCRL). We use the non-linear sigma model (NLSM) to numerically calculate the minimum energy configurations of this lattice around the $ν=1$ quantum Hall ground state. Our variational ansatz contains an angle $θ$, chara

Subhanjoy Mohanty, Gibor Basri, Frank Shu, France Allard

Recent observations show that chromospheric activity in late-M and L dwarfs is much lower than in the earlier M types, in spite of comparatively rapid rotation. We investigate the possibility that this drop-off in activity results from the very high electrical resistivities in the dense, cool and predominantly neutral atmospheres of late-M and L dwarfs. We c

S. Peng Oh

Recent observations of high redshift quasars at z~6 have finally revealed complete Gunn-Peterson absorption. However, this at best constrains the volume-weighted and mass-weighted hydrogen neutral fractions to be greater than 10^-3 and 10^-2 respectively; stronger constraints are not possible due to the high optical depth for hydrogen Lyman transitions. Here

Inseok Song, M. S. Bessell, B. Zuckerman

We present spectroscopic measurements of the 23 new candidate members of the TW Hydrae Association from Makarov & Fabricius (2000). Based on Halpha and Li 6708 A strengths together with location on a color-magnitude diagram for Hipparcos TWA candidates, we found only three possible new members (TYC 7760-0835-1, TYC 8238-1462-1, and TYC 8234-2856-1) in additi

T. D. Willis

An Isotropic Diffuse Gamma-Ray Background (IDGRB) in the spectral range 30-10,000 MeV was first reported in the early 1970&#39;s using measurements made by the SAS-2 instrument. Data recorded by the Energetic Gamma Ray Experiment Telescope (EGRET) on board the Compton Gamma Ray Observatory (CGRO) over the last 4 years are analysed in order to extract the bes

Tom Theuns, Joop Schaye, Saleem Zaroubi, Tae-Sun Kim

The temperature of the diffuse, photo-heated intergalactic medium (IGM) depends on its reionization history because the thermal time scales are long. The widths of the hydrogen Lyman-alpha absorption lines seen in the spectra of distant quasars that arise in the IGM can be used to determine its temperature. We use a wavelet analysis of the Lyman-alpha forest

P. D. Morley, Ivan Schmidt

We employ an effective gravitational stellar final collapse model which contains the relevant physics involved in this complex phenomena: spherical radical infall in the Schwarzschild metric of the homogeneous core of an advanced star, giant magnetic dipole moment, magnetohydrodynamic material response and realistic equations of state (EOS). The electromagne

Jens C. Niemeyer

Inflation can act as a space-time microscope for Planck or string scale effects, leaving potentially observable traces in the primordial perturbation spectrum. I discuss two frameworks that were used recently to study this phenomenon: nonlinear dispersion and short distance uncertainty.

M. Blazejowski, M. Sikora, R. Moderski, G. Madejski

We demonstrate that the spectral differences between Flat Spectrum Radio Quasars (FSRQ) with steep gamma-ray spectra (MeV-blazars) and FSRQ with flat gamma-ray spectra (GeV-blazars) can be explained by assuming that in the MeV-blazars, the production of gamma-rays is dominated by Comptonization of infrared radiation of hot dust, whereas in the GeV-blazars --

Kathleen E. Kraemer, G. C. Sloan, Stephan D. Price, Helen J. Walker

The Infrared Space Observatory observed over 900 objects with the Short Wavelength Spectrometer in full-grating-scan mode (2.4-45.2 micron). We have developed a comprehensive system of spectral classification using these data. Sources are assigned to groups based on the overall shape of the spectral energy distribution (SED). The groups include naked stars,

Mercedes E. Filho, Peter D. Barthel, Luis C. Ho

The LINER galaxies NGC 2911, NGC 3079, NGC 3998, and NGC 6500 were observed at 5 GHz with the European VLBI Network at a resolution of 5 milliarcsecond and found to possess flat-spectrum, variable, high-brightness temperature ($T_{\rm B} > 10^8$ K) radio cores. These radio characteristics reinforce the view that these LINERs host central engines associated w

Alessandro Marconi

It has long been suspected that Active Galactic Nuclei are powered by accretion of matter onto massive black holes and this belief implies their presence in the nuclei of most nearby galaxies as &#34;relics&#34; of past activity. Just a few years ago this was considered a paradigm but, recently, new ground-based and Hubble Space Telescope observations are pr

Jay P. Norris

Spectral lags are deduced for 1437 long GRBs with peak fluxes extending to near the BATSE trigger threshold. The lags are modeled to approximate the observed distribution in the peak flux-lag plane, realizing a noise-free representation. Assuming a two-branch lag-luminosity relationship, the lags are self- consistently corrected for cosmological effects to y

C. Dominik, H. Nuebold

Focussing on preplanetary grains growth, we discuss the properties of dust aggregation driven by magnetic dipole forces. While there is no direct evidence for the existence of magnetic grains present in the solar nebula, there are reasons to assume they may have been present. We derive analytical expressions for the cross-section of two interacting dipoles.

A. Chrysostomou, D. K. Aitken, T. Jenness, C. J. Davis

We present 850 micron imaging polarimetry of the W51A massive star forming region performed with SCUBA on the JCMT. From the polarimetry we infer the column-averaged magnetic field direction, projected onto the plane of the sky. We find that the magnetic field geometry in the region is complicated. We compare the field geometry with 6 cm and CS J=7-6 emissio

Fumitaka Nakamura, Masayuki Umemura

In the context of star formation through fragmentation of an extremely metal-deficient protogalactic cloud, the gravitational collapse of filamentary gas clouds is explored with 1D numerical hydrodynamics coupled with non-equilibrium chemistry of H$_2$ and HD. It is found that the cloud evolution is governed mainly by the initial central density ($n_{\rm c,0

M. G. Burton

The 2.12 micron v=1-0 S(1) line of molecular hydrogen has been imaged in the Hourglass region of M8. The line is emitted from a roughly bipolar region, centred around the O7 star Herschel 36. The peak H2 1-0 S(1) line intensity is 8.2 x 10E-15 erg s-1 cm-2 arcsec-2. The line centre emission velocity varies from -25 kms in the SE lobe to +45 kms in the NW lob

Masayuki Akiyama, Yoshihiro Ueda, Kouji Ohta

To understand luminous AGNs in the z<1 universe, the ASCA AGN samples are the best at present. Combining the identified sample of AGNs from ASCA Large Sky Survey and Medium Sensitivity Survey, the sample of hard X-ray selected AGNs have been expanded up to 108 AGNs above the flux limit of 10^{-13} erg s^{-1} cm^{-2} in the 2-10 keV hard X-ray band. We discus

C. G. Tinney, Chris McCarthy, Hugh R. A. Jones, R. Paul Butler

We present the results of ultraviolet echelle spectroscopy of a sample of fifty nine F,G,K and M stars from the Anglo-Australian Planet Search target list. Ca II activity indices, which are essential in the interpretation of planet detection claims, have been determined for these stars and placed on the Mount Wilson Rhk system.

M. Kontsevich, A. Zorich

Consider the moduli space of pairs (C,w) where C is a smooth compact complex curve of a given genus and w is a holomorphic 1-form on C with a given list of multiplicities of zeroes. We describe connected components of this space. This classification is important in the study of dynamics of interval exchange transformations and billiards in rational polygons,

M. Romero-Bastida, E. Braun

The problem of relating microscopic chaos to macroscopic behavior in a many-degrees-of-freedom system is numerically investigated by analyzing statistical properties associated to the position and momentum of a heavy impurity embedded in a chain of nearest-neighbor anharmonic Fermi-Pasta-Ulam oscillators. For this model we have found that the behavior of the

Rennan Barkana

Recently, Lanzetta et al. (2002) have measured the distribution of star formation rate intensity in galaxies at various redshifts. This data set has a number of advantages relative to galaxy luminosity functions; the effect of surface-brightness dimming on the selection function is simpler to understand, and this data set also probes the size distribution of

M. C. B. Abdalla, E. L. Graca, I. V. Vancea

The entropy of the states associated to the solutions of the equations of motion of the bosonic open string with combinations of Neumann and Dirichlet boundary conditions is given. Also, the entropy of the string in the states $| A^i > = α^{i}_{-1} |0>$ and $| ϕ^a > = α^{a}_{-1} |0>$ that describe the massless fields on the world-volume of the Dp-brane is co

Alexander Knebe, Alvaro Dominguez

We present the study of ten random realizations of a density field characterized by a cosmological power spectrum P(k) at redshift z=50. The reliability of such initial conditions for n-body simulations are tested with respect to their correlation properties. The power spectrum P(k), and the mass variance sigmaM(r) do not show detectable deviations from the

John R. Thorstensen, William H. Fenton, Joseph O. Patterson, Jonathan Kemp

We present spectroscopy and time-series photometry of the newly discovered dwarf nova 1RXS J232953.9+062814. Photometry in superoutburst reveals a superhump with a period of 66.06(6) minutes. The low state spectrum shows Balmer and HeI emission on a blue continuum, and in addition shows a rich absorption spectrum of type K4 +- 2. The absorption velocity is m

Gary T. Horowitz, Kengo Maeda

It has recently been shown that there exist stable inhomogeneous neutral black strings in higher dimensional gravity. These solutions were motivated by the fact that the corresponding homogeneous solutions are unstable. We show that there exist new inhomogeneous black string and black p-brane solutions even when the corresponding translationally invariant so

Edward Anderson, Julian Barbour

Barbour, Foster and Ó Murchadha have recently developed a new framework, called here {\it{the 3-space approach}}, for the formulation of classical bosonic dynamics. Neither time nor a locally Minkowskian structure of spacetime are presupposed. Both arise as emergent features of the world from geodesic-type dynamics on a space of 3-dimensional metric--matter

Arnd Bäcker, Achim Manze, Bodo Huckestein, Roland Ketzmerick

We study the isolated resonances occurring in conductance fluctuations of quantum systems with a classically mixed phase space. We demonstrate that the isolated resonances and their scattering states can be associated to eigenstates of the closed system. They can all be categorized as hierarchical or regular, depending on where the corresponding eigenstates

I. E. Smolyarenko, F. M. Marchetti, B. D. Simons

We explore the influence of external perturbations on the energy levels of a Hamiltonian drawn at random from the Gaussian unitary distribution of Hermitian matrices. By deriving the joint distribution function of eigenvalues, we obtain the (n,m)-point parametric correlation function of the initial and final density of states for perturbations of arbitrary r

M. Murgia, A. Crapsi, L. Moscadelli, L. Gregorini

We combine the radio continuum images from the NRAO VLA Sky Survey with the CO-line observations from the extragalactic CO survey of the Five College Radio Astronomy Observatory to study the relationship between molecular gas and the star formation rate within the disks of 180 spiral galaxies at 45&#34; resolution. We find a tight correlation between these q

N. Read

Recent papers by Finkelstein, Galiautdinov, and coworkers {[J. Math. Phys. 42, 1489, 3299 (2001)]} discuss a suggestion by Wilczek that nonabelian projective representations of the permutation group can be used as a new type of particle statistics, valid in any dimension. Wilczek&#39;s suggestion was based in part on an analysis by Nayak and Wilczek (NW) of

J. Duflo, A. P. Zuker

A gross estimate of the neutron skin [0.80(5)$(N-Z)/A$ fm] is extracted from experimental proton radii, represented by a four parameter fit, and observed mirror displacement energies (CDE). The calculation of the latter relies on an accurately derived Coulomb energy and smooth averages of the charge symmetry breaking potentials constrained to state of the ar

C. Alcock, R. A. Allsman, D. R. Alves, A. C. Becker

We present a method for solving the lightcurve of an eclipsing binary system which contains a Cepheid variable as one of its components as well as the solutions for three eclipsing Cepheids in the Large Magellanic Cloud (LMC). A geometric model is constructed in which the component stars are assumed to be spherical and on circular orbits. The emergent system

L. R. Penny, D. R. Gies, J. H. Wise, D. J. Stickland

We present the first orbital elements for the massive close binary, HD 115071, a double-lined spectroscopic binary in a circular orbit with a period of 2.73135 +/- 0.00003 days. The orbital semiamplitudes indicate a mass ratio of M_2/M_1 = 0.58 +/- 0.02 and yet the stars have similar luminosities. We used a Doppler tomography algorithm to reconstruct the ind

The ZEUS Collaboration

The exclusive photoproduction of J/psi mesons, gamma p->J/psi p, has been studied in ep collisions with the ZEUS detector at HERA, in the kinematic range 20<W<290 GeV, where W is the photon-proton centre-of-mass energy. The J/psi mesons were reconstructed in the muon and the electron decay channels using integrated luminosities of 38 pb^-1 and 55 pb^-1, resp

Paul Jefferies, David Lamper, Neil F. Johnson

We provide an analytic, microscopic analysis of extreme events in an adaptive population comprising competing agents (e.g. species, cells, traders, data-packets). Such large changes tend to dictate the long-term dynamical behaviour of many real-world systems in both the natural and social sciences. Our results reveal a taxonomy of extreme events, and provide

K. Urbanowski

We show that the diagonal matrix elements of the effective Hamiltonian governing the time evolution in the subspace of states of an unstable particle and its antiparticle need not be equal at $t > t_{0}$ ($t_{0}$ is the instant of creation of the pair) when the total system under consideration is CPT invariant but CP noninvariant. To achieve this we use the

Stefano Arnone, Antonio Gatti, Tim R. Morris

The requirement that the quantum partition function be invariant under a renormalization group transformation results in a wide class of exact renormalization group equations, differing in the form of the kernel. Physical quantities should not be sensitive to the particular choice of the kernel. We demonstrate this scheme independence in four dimensional sca

Roberto Onofrio, Carlo Presilla

We propose the use of a combined optical dipole trap to achieve Fermi degeneracy by sympathetic cooling with a different bosonic species. Two far-detuned pairs of laser beams focused on the atomic clouds are used to confine the two atomic species with different trapping strengths. We show that a deep Fermi degeneracy regime can be potentially achieved earlie

I. Brevik, J. B. Aarseth, J. S. Høye

The Casimir mutual free energy F for a system of two dielectric concentric nonmagnetic spherical bodies is calculated, at arbitrary temperatures. The present paper is a continuation of an earlier investigation [Phys. Rev. E {\bf 63}, 051101 (2001)], in which F was evaluated in full only for the case of ideal metals (refractive index n=infinity). Here, analog

V. N. Krivoruchko, E. A. Koshina

We study a magnetic proximity effect at superconductor (S) - ferromagnet (F) interface. It is shown that due to an exchange of electrons between the F and S metals ferromagnetic correlations extend into the superconductor, being dependent on interface parameters. We show that ferromagnetic exchange field pair breaking effect leads to a formation of subgap ba

S. M. Troshin, N. E. Tyurin

We provide a brief topical outline of the persisting problem of the hyperon polarization and consider some future experimental prospects. The predictions which deserve experimental verification are proposed.

Sebastien Gurrieri, Annamaria Kiss

We consider the geometrical formulation in central charge superspace of the N=4 supergravity containing an antisymmetric tensor gauge field. The theory is on-shell, so clearly, the constraints used for the identification of the multiplet together with the superspace Bianchi identities imply equations of motion for the component fields. We deduce these equati