January 2004 arXiv papers — page 17

Péter Bálint, Serge Troubetzkoy

Introducing the rotor interaction in the integrable system of the annulus billiard produces a variety of dynamical phenomena, from integrability to ergodicity.

Michael Aschbacher, Michael K. Kinyon, J. D. Phillips

A loop $(X,\circ)$ is said to be a Bruck loop if it satisfies the (right) Bol identity $((z\circ x)\circ y)\circ x = z\circ ((x\circ y)\circ x)$ and the automorphic inverse property $(x\circ y)^{-1}=x^{-1}\circ y^{-1}$. If $X$ is a finite Bruck loop and $G$ is the group generated by all right translations $R(x): y\mapsto y\circ x$, then we show that $X$ and

Stephane Zahnd

Let $k$ be a field of characteristic 0 and $G$ a linear algebraic $k$-group. When $G$ is abelian, it is well known that torsors under $G_{X}$ over a $k$-scheme $π:X\to \textup{Spec} k$ provide an obstruction to the existence of $k$-rational points on $X$, since Leray spectral sequence gives rise (when $X$ is 'nice', e.g. $X$ smooth and proper) to an

A. Knauf, I. A. Taimanov

It is shown that for generic configuration of the centres at high energy levels the n-centre problem is completely integrable by using $C^\infty$ integrals of the motion however it is not integrable in terms of real analytic functions

Gregory Buck, Jonathan Simon

We establish a new fundamental relationship between total curvature of knots and crossing number. If K is a smooth knot in 3-space, R the cross-section radius of a uniform tube neighborhood of K, L the arclength of K, and k the total curvature of K, then (up to a coefficient independent of K), crossing number of K < (k)(L/R). There are families of knots whos

Marcos Jardim

We review the construction known as the Nahm transform in a generalized context, which includes all the examples of this construction already described in the literature. The Nahm transform for translation invariant instantons on $\real^4$ is presented in an uniform manner. We also analyze two new examples, the first of which being the first example involvin

Pavel Andreev

We give positive answers for questions by Berestovskii. Namely, we prove that every bijection of locally compact geodesically complete and connected at infinity CAT(0)-space $X$ onto itself preserving some fixed distance or satellite relations is an isometry of this space. The proof of this theorem is based on another result stated by Berestovskii as a probl

Richard P. Stanley

Let P be a poset with elements 1,2,...,n. We say that P is sign-balanced if exactly half the linear extensions of P (regarded as permutations of 1,2,...,n) are even permutations, i.e., have an even number of inversions. This concept first arose in the work of Frank Ruskey, who was interested in the efficient generation of all linear extensions of P. We surve

R. W. R. Darling, J. R. Norris

The theme of this paper is the derivation of analytic formulae for certain large combinatorial structures. The formulae are obtained via fluid limits of pure jump type Markov processes, established under simple conditions on the Laplace transforms of their Levy kernels. Furthermore, a related Gaussian approximation allows us to describe the randomness which

Samir D. Mathur

We argue that bound states of branes have a size that is of the same order as the horizon radius of the corresponding black hole. Thus the interior of a black hole is not `empty space with a central singularity&#39;, and Hawking radiation can pick up information from the degrees of freedom of the hole.

M. Gasperini, M. Giovannini, G. Veneziano

String-inspired cosmologies, whereby a non-singular curvature bounce is induced by a general-covariant, $T$-duality-invariant, non-local dilaton potential, are used to study numerically how inhomogeneities evolve and to compare the outcome with analytic expressions obtained through different matching conditions across the bounce. Good agreement is found if c

M. Mansour, E. H. Zakkari

The splitting of a $Q$-deformed boson, in the $Q\to q=e^{\frac{\QTR{rm}{2πi}}{\QTR{rm}{k}}}$ limit, is discussed. The equivalence between a $Q$-fermion and an ordinary one is established. The properties of the quantum (super)Virasoro algebras when their deformation parameter $Q$ goes to a root of unity, are investigated. These properties are shown to be rela

T. Tsuneyama

As is well known, the universally accepted theory as quantum gravity (QG) doesn&#39;t exist. One of the main reasons for that is that quantized general relativity is perturbatively nonrenormalizable. But there are several theories whose low-energy effective action is general relativity such as super string theory, supergravity and so on. On the other hand th

Richard Shurtleff

Nontrivial translation matrices occur for spin (A,B)+(C,D) with |A-C| = |B-D| = 1/2, necessarily associating a (C,D) field with a spin (A,B) field. Including translation matrices in covariant non-unitary Poincare representations also introduces new gauge terms in the construction of massless particle fields from canonical unitary fields. In the usual procedu

Edi Halyo

We obtain models of chaotic, slow--roll, hybrid and D--term inflation from the Hanany--Witten brane configuration and its deformations. The deformations are given by the different orientations of the branes and control the parameters of the scalar potential such as the inflaton mass, Yukawa couplings and the anomalous D--term. The different inflationary mode

G. Azuelos, P. -H. Beauchemin, C. P. Burgess

We examine whether the ATLAS detector has sensitivity to extra-dimensional scalars (as opposed to components of higher-dimensional tensors which look like 4D scalars), in scenarios having the extra-dimensional Planck scale in the TeV range and $n \ge 2$ nonwarped extra dimensions. Such scalars appear as partners of the graviton in virtually all higher-dimens

Ralf Lehnert

Quantum-gravity effects are expected to be suppressed by the Planck mass. For experimental progress it is therefore important to identify potential signatures from Planck-scale physics that are amenable to ultrahigh-precision tests. It is argued that minuscule violations of Lorentz and CPT symmetry are candidate signals. In addition, theoretical and experime

M. E. Carrington

We work with $ϕ^4$ theory and study the 4PI effective action at 3-loop order. We discuss the relationship between the equations of motion obtained by taking functional derivatives of the effective action with respect to the variational parameters, and the Schwinger-Dyson (SD) equations. We show that the equation obtained by differentiating with respect to th

Erik Thomé

The transverse momentum of a colour-singlet massive particle in a hadronic collision is built up by two components, the perturbative effect of parton branchings and the nonperturbative effect of primordial kT. In previous studies of transverse momentum spectra for Z0 production at the Tevatron, the best fit to the experimental data are given when the primord

W. -W. Li, Y. -R. Liu, P. -Z. Huang, W. -Z. Deng

If the $J^P$ of $Θ_5^+$ and $Ξ_5^{--}$ pentaquarks is really found to be ${1\over 2}^+$ by future experiments, they will be accompanied by $J^P={3\over 2}^+$ partners in some models. It is reasonable to expect that these $J^P={3\over 2}^+$ states will also be discovered in the near future with the current intensive experimental and theoretical efforts. We es

V. N. Kornoukhov, A. S. Starostin

One of the main problems of neutrino physics is the measurement of mixing parameter sin2(2 teta 1 3). At present time several projects of reactor experiments with sensitivity of sin2(2 teta 1 3) ~ 0.01 are under discussion. Practically, all of them are based on the principle &#39;one reactor- two detectors&#39;. Such approach suppose to use NPP reactor with

B. Aubert, BABAR Collaboration

We report a measurement of the production ratio of charged and neutral B mesons from Upsilon(4S) decays based on the ratio of efficiency-corrected yields for the charmonium modes J/psi K^+ and J/psi K^{0}_{S} with 81.9 fb^-1 of data collected with the BABAR detector on the Upsilon(4S) resonance at 10.580 GeV. We find a value of 1.006 +/- 0.036 (stat) +/- 0.0

A. Lai

In data taken with the NA48 experiment at the CERN SPS in 1999, 730 candidates of the weak radiative hyperon decay Xi0 -> Lambda gamma have been found with an estimated background of 58+-8 events. From these events the Xi0 -> Lambda gamma decay asymmetry has been determined to alpha(Xi0 -> Lambda gamma) = -0.78 +- 0.18_stat +- 0.06_syst, which is the first e

The OPAL collaboration, G. Abbiendi

Approximately 438 pb-1 of e+e- data from the OPAL detector, taken with the LEP collider running at centre-of-mass energies of 192-209 Gev, are analyzed to search for evidence of chargino pair production, e+e- -> tilde chi^+_1 tilde chi^-_1, or neutralino associated production, e+e- -> tilde chi^0_2 tilde chi^0_1. Limits are set at the 95% confidence level on

The DELPHI Collaboration, J. Abdallah

Final results from the DELPHI Collaboration on the lifetime of B+ and B0 mesons and the mean b-hadron lifetime, are presented using the data collected at the Z0 peak in 1994 and 1995. Elaborate, inclusive, secondary vertexing methods have been employed to ensure a b-hadron reconstruction with good efficiency. To separate samples of B+ and B0 mesons, high per

The DELPHI Collaboration, J. Abdallah

Data from Z decays in DELPHI have been searched for anti-B0d -> D*+ l- anti-nu_l with the D*+ decaying to D0 pi+ and D0 -> K- pi+, K- pi+ pi+ pi- or K- pi+ (pi0). These events are used to measure the CKM matrix element |V_cb| and the form factor slope, rho_{A_1}^2: F_D*(1)|Vcb| = 0.0392 +/- 0.0018 +/- 0.0023; rho_{A_1}^2 = 1.32 +/- 0.15 +/- 0.33 correspondin

The DELPHI Collaboration, J. Abdallah

Searches for HZ production with the Higgs boson decaying into an invisible final state were performed using the data collected by the DELPHI experiment at centre-of-mass energies between 188 GeV and 209 GeV. Both hadronic and leptonic final states of the Z boson were analysed. In addition to the search for a heavy Higgs boson, a dedicated search for a light

Chunhui Chen

Using a subset of the current Run II data, the CDF and \D0 have performed several measurements on heavy flavor production. In this paper, we present a new measurement of prompt charm meson production by CDF. We also report the latest CDF II measurements of inclusive $J/Ψ$ production and $b$-production without requirement of minimum transverse momentum on $J/

Matthew D. Duez, Stuart L. Shapiro, Hwei-Jang Yo

We present a numerical code designed to study astrophysical phenomena involving dynamical spacetimes containing black holes in the presence of relativistic hydrodynamic matter. We present evolutions of the collapse of a fluid star from the onset of collapse to the settling of the resulting black hole to a final stationary state. In order to evolve stably aft

M. Sharif

We derive matter collineations for some static spherically symmetric spacetimes and compare the results with Killing, Ricci and Curvature symmetries. We conclude that matter and Ricci collineations are not, in general, the same.

M. Sharif

Two models are given by crossing the Friedmann metrics with Schwarzschild and Kerr metrics. In these evolving universes with a gravitational source, the force four-vector and the corresponding potentials are evaluated.

M. Sharif

We take an axisymmetric rotating universe model by crossing with a time dependent factor and evaluate its force and momentum in this evolving universe. It is concluded that it behaves exactly like a Friedmann model. We also extend this conclusion to the most general cosmological model.

M. Sharif

A new approach has been used to evaluate the momentum and angular momentum of the isotropic and homogeneous cosmological models. It is shown that the results obtained for momentum exactly coincide with those already available in the literature. However, the angular momentum expression coincides only for the closed Friedmann model.

T. Harko, M. K. Mak

The behavior near the initial singular state of the anisotropy parameter of the arbitrary type, homogeneous and anisotropic Bianchi models is considered in the framework of the brane world cosmological models. The matter content on the brane is assumed to be an isotropic perfect cosmological fluid, obeying a barotropic equation of state. To obtain the value

Laura Bozzelli

We consider the problem of model--checking for Process Rewrite Systems (PRSs) in normal form. In a PRS in normal form every rewrite rule either only deals with procedure calls and procedure termination, possibly with value return, (this kind of rules allows to capture Pushdown Processes), or only deals with dynamic activation of processes and synchronization

Alexandru Macridin, George. A. Sawatzky, Mark Jarrell

We present a diagrammatic Monte Carlo study of the properties of the Hubbard-Holstein bipolaron on a two-dimensional square lattice. With a small Coulomb repulsion, U, and with increasing electron-phonon interaction, and when reaching a value about two times smaller than the one corresponding to the transition of light polaron to heavy polaron, the system su

O. Waldmann, S. Carretta, P. Santini, R. Koch

The magnetic grid molecule Mn(II)-[3 x 3] has been studied by high-field torque magnetometry at 3He temperatures. At fields above 5 T, the torque vs. field curves exhibit an unprecedented oscillatory behavior. A model is proposed which describes these magneto oscillations well.

R. V. R. Pandya

An almost-Markovian model equation is proposed for Fourier modes of velocity field of isotropic turbulence whose statistical properties are identical to those governed by equations of Local Energy Transfer theory of turbulence [McComb et al., J. Fluid Mech. {\bf 245}, 279 (1992)] compatible with the Kolmogorov spectrum.

Michael Creutz

The Bak-Tang-Wiesenfeld sandpile model provdes a simple and elegant system with which to demonstate self-organized criticality. This model has rather remarkable mathematical properties first elucidated by Dhar. I demonstrate some of these properties graphically with a simple computer simulation.

T. Vekua, G. I. Japaridze, H. -J. Mikeska

We study the phase diagram of spin ladders with ferromagnetic legs under the influence of a symmetry breaking magnetic field in the weak coupling effective field theory by bosonization. For antiferromagnetic interleg coupling we identify two phase transitions introduced by the external magnetic field. In order to establish the universality of the phases we s

G. Bonanno, G. Caldarelli, F. Lillo, S. Micciche`

We review the recent approach of correlation based networks of financial equities. We investigate portfolio of stocks at different time horizons, financial indices and volatility time series and we show that meaningful economic information can be extracted from noise dressed correlation matrices. We show that the method can be used to falsify widespread mark

H. Bermudez, D. A. Hammer, D. E. Discher

The bending rigidity $k_c$ of bilayer vesicles self-assembled from amphiphilic diblock copolymers has been measured using single and dual-micropipet techniques. These copolymers are nearly a factor of 5 greater in hydrophobic membrane thickness $d$ than their lipid counterparts, and an order of magnitude larger in molecular weight $\bar{M}_n$. The macromolec

V. K. Thorsmolle, R. D. Averitt, X. Chi, D. J. Hilton

We present measurements of the transient photoconductivity in pentacene single crystals using optical-pump THz-probe spectroscopy. We have measured the temperature and fluence dependence of the mobility of the photoexcited charge carriers with picosecond resolution. The pentacene crystals were excited at 3.0 eV which is above the bandgap of ~2.2 eV and the i

J. M. D. Coey, A. P. Douvalis, C. B. Fitzgerald, M. Venkatesan

Thin films grown by pulsed-laser deposition from targets of Sn0.95Fe0.05O2 are transparent ferromagnets with Curie temperature and spontaneous magnetization of 610 K and 2.2 Am2kg-1, respectively. The 57Fe Mossbauer spectra show the iron is all high-spin Fe3+ but the films are magnetically inhomogeneous on an atomic scale, with only 23 % of the iron ordering

A. D. Jackson, G. M. Kavoulakis, E. Lundh

We examine an effectively repulsive Bose-Einstein condensate of atoms that rotates in a quadratic-plus-quartic potential. With use of a variational method we identify the three possible phases of the system (multiple quantization, single quantization, and a mixed phase) as a function of the rotational frequency of the gas and of the coupling constant. The de

J. E. Magee, J. Warwicker, L. Lue

We have performed parallel tempering Monte Carlo simulations using a simple continuum heteropolymer model for proteins. All ten heteropolymer sequences which we have studied have shown first-order transitions at low temperature to ordered states dominated by single chain conformations. These results are in contrast with the theoretical predictions of the ran

Sumiyoshi Abe, G. Kaniadakis, A. M. Scarfone

The generalized entropic measure, which is optimized by a given arbitrary distribution under the constraints on normalization of the distribution and the finite ordinary expectation value of a physical random quantity, is considered and its Lesche stability property (that is different from thermodynamic stability) is examined. A general condition, under whic

R. Asgari, B. Davoudi, B. Tanatar

Recent experiments on two-dimensional (2D) electron systems have found a sharp increase in the effective mass of electrons with decreasing electron density. In an effort to understand this behavior we employ the many-body theory to calculate the quasiparticle effective mass in 2D electron systems. Because the low density regime is explored in the experiments

Claire Loison, Michel Mareschal, Kurt Kremer, Friederike Schmid

We investigate thermal fluctuations in a smectic A phase of an amphiphile-solvent mixture with molecular dynamics simulations. We use an idealized model system, where solvent particles are represented by simple beads, and amphiphiles by bead-and-spring tetramers. At a solvent bead fraction of 20 % and sufficiently low temperature, the amphiphiles self-assemb

Jozsef Steger, Peter Vaderna, Gabor Vattay

Traffic modeling of communication networks such as Internet has become a very important field of research. A number of interesting phenomena are found in measurements and traffic simulations. One of them is the propagation of congestion waves opposite to the main packet flow direction. The purpose of this paper is to model and analyze packet congestion on a

O. Bleibaum, B. Sandow, W. Schirmacher

We present a theory for tunneling spectroscopy in a break-junction semiconductor device for materials in which the electronic conduction mechanism is hopping transport. Starting from the conventional expression for the hopping current we develop an expression for the break-junction tunnel current for the case in which the tunnel resistance is much larger tha

Uday Kumar Khan, Jimmy Sebastian, N. Kamaraju, Andal Narayanan

Unusually narrow fluorescence peaks are seen from Rubidium-85 atoms under the action of two driving laser fields that are in a three dimensional molasses configuration. One of the lasers is held at a fixed detuning from the &#34;cooling&#34; transition, while the other is scanned across the &#34;repumping&#34; transitions. The fluorescence peaks are split in

Andal Narayanan, R. Srinivasan, Ashok Vudayagiri, Uday Kumar Khan

The unusually narrow features in the fluorescence from Rubidium-85 driven by cooling and repumper laser fields, reported in an earlier experiment [1] are explained on the basis of a four-level density matrix calculation. Quantum effects alter the efficiency of atom transfer by the probe (repumper) laser to the levels connected by the pump (cooling) laser. Th

H. Caps, S. Dorbolo, S. Ponte, H. Croisier

We present an experimental study of the motion of a circular disk spun onto a table. With the help of a high speed video system, the temporal evolutions of (i) the inclination angle $α$, (ii) the angular velocity $ω$ and (iii) the precession rate $Ω$ are studied. The influence of the mass of the disk and the friction between the disk and the supporting surfa

N. I. Matskevich, A. I. Romanenko, L. V. Yakovkina, Th. Wolf

We studied thermochemical characteristics of the Sm1+xBa2-xCu3Oy single crystals by solution calorimetry. Dependences of formation enthalpies from samarium content were constructed. It was established that solid solutions on the bases of Sm123 could be decomposed both in inert and in oxygen atmosphere into different mixtures. We supposed that solid solutions

Michio Watanabe, Yasunobu Nakamura, Jaw-Shen Tsai

We have developed a fabrication process for nanoscale tunnel junctions which includes focused-ion-beam etching from different directions. By applying the process to a Nb/(Al-)Al_2O_3/Nb trilayer, we have fabricated a Nb single-electron transistor (SET), and characterized the SET at low temperatures, T=0.04-40 K. The superconducting gap energy and the transit

Noboru Fukushima, Andreas Honecker, Stefan Wessel, Wolfram Brenig

Using a combination of high-temperature series expansion, exact diagonalization and quantum Monte Carlo, we perform a complementary analysis of the thermodynamic properties of quasi-one-dimensional mixed-spin systems with alternating magnetic moments. In addition to explicit series expansions for small spin quantum numbers, we present an expansion that allow

Qiuping A. Wang

The necessary information for specifying a complex system may not be completely accessible to us, i.e., to mathematical treatments. This is not to be confounded with the incompleteness of our knowledge about whatever systems or nature, since here information is our ignorance. In conventional statistics and information theories, this information or ignorance

Ray Jayawardhana

Brown dwarfs, which occupy a fuzzy gap in mass between stars and planets, appear to be common both in the solar neighborhood and in star-forming regions. Their origin is a topic of significant current interest and debate. Some astronomers have suggested that brown dwarfs are stellar embryos, ejected from newborn multiple star systems. Others argue that they

Frank Wilczek

This is a broad and in places unconventional overview of the strengths and shortcomings of our standard models of fundamental physics and of cosmology. The emphasis is on ideas that have accessible experimental consequences. It becomes clear that the frontiers of these subjects share much ground in common.

Darrin Casebeer, Edward A. Baron, David Branch, Karen Leighly

We find that spectra of certain Iron Low Ionization Broad Absorption Line (FeLOBAL) QSOs, which are characterized by low--ionization emission and blue shifted absorption lines, can be well matched with the spectral synthesis code SYNOW. SYNOW is a resonance scattering code and assumes that line emission comes from a single line forming region. This interpret

V. Karas, J. -M. Hure, O. Semerak

Fluid discs and tori around black holes are discussed within different approaches and with the emphasis on the role of disc gravity. First reviewed are the prospects of investigating the gravitational field of a black hole--disc system by analytical solutions of stationary, axially symmetric Einstein&#39;s equations. Then, more detailed considerations are fo

Edward L. Fitzpatrick

I review the basic properties of interstellar extinction in the Milky Way galaxy, focusing primarily on the wavelength dependence within the IR through UV spectral region. My primary goal is to review the evidence supporting the idea that Galactic extinction curves can be considered a 1-parameter family characterized by their value of R(V) = A(V)/E(B-V). Bas

Scott J Kenyon, Benjamin C Bromley

We use a multiannulus accretion code to investigate debris disks in the terrestrial zone, at 0.7-1.3 AU around a 1 solar mass star. Terrestrial planet formation produces a bright dusty ring of debris with a lifetime of at least 1 Myr. The early phases of terrestrial planet formation are observable with current facilities; the late stages require more advance

J. Einasto

We generate the 2-dimensional high-resolution density field of galaxies of the Early Data Release of the Sloan Digital Sky Survey and the Las Campanas Redshift Survey with a smoothing length 0.8 Mpc/h to extract clusters and groups of galaxies, and a low-resolution field with a smoothing length 10 Mpc/h to extract superclusters of galaxies. We investigate pr

J. Einasto

A review of the study of dark matter is given, starting with earliest studies and finishing with the establishment of the standard Cold Dark Matter paradigm in mid 1980-s. Particular attention is given to the collision of the classical and new paradigms concerning the matter content of the Universe. Also the amount of baryonic matter, dark matter and dark en

Richard A. Battye, Rod D. Davies, Jochen Weller

We discuss the possibility of performing blind surveys to detect large-scale features of the universe using 21cm emission. Using instruments with approx. 5&#39;-10&#39; resolution currently in the planning stage, it should be possible to detect virialized galaxy clusters at intermediate redshifts using the combined emission from their constituent galaxies, a

M. E. van den Ancker, P. F. C. Blondel, H. R. E. Tjin A Djie, K. N. Grankin

We report on a recent event in which, after more than a decade of slowly fading, the visual brightness of the massive young binary Z CMa suddenly started to rise by about 1 magnitude in December 1999, followed by a rapid decline to its previous brightness over the next six months. This behaviour is similar to that exhibited by this system around its eruption

Torsten A. Ensslin, Steen H. Hansen

Populations of relativistic electrons in clusters of galaxies should imprint a characteristic spectral distortion signature on the Cosmic Microwave Background photons - the relativistic Sunyaev-Zeldovich (SZ) effect. We investigate how sensitive PLANCK and successor experiments will be in detecting or constraining the total optical depth tau of relativistic

Bodo L. Ziegler

An introduction is given to projects investigating galaxy evolution quantitatively by spectroscopic observations of very distant galaxies that have weak apparent brightnesses and small sizes as it is feasible with 10m-class telescopes like SALT. Such methods encompass scaling relations like the Tully-Fisher and Fundamental Plane relations that can be utilize

D. Mitra, J. H. Seiradakis

The linear polarization position angle (PPA) of pulsar emission shows a wide variety of structures, which deviates from the classical rotating vector model. In this study we investigate the effect on the PPA due to emission arising from a range of heights. We demonstrate that by appropriately choosing the emission height we can reconstruct the PPA sweep acro

Thomas J. Maccarone, Arunav Kundu, Stephen E. Zepf

We show that irradiation induced stellar winds can explain two important metallicity effects in X-ray binaries - the higher numbers and the softer spectra of the X-ray binaries in metal rich globular clusters compared to the metal poor ones. As has been previously noted by Iben, Tutukov and Fedorova, the winds should be stronger at lower metallicity due to l

M. Marconi, G. Fiorentino, F. Caputo

A theoretical investigation of the pulsation behavior of so-named ``anomalous&#39;&#39; Cepheids is presented. The study is based on nonlinear convective pulsation models with $Z$=0.0001 and 0.0004, mass in the range 1.3-2.2 Mo and various luminosity levels. Based on these computations, we derive period, bolometric light curves and the edges of the instabili

D. Stello, H. Kjeldsen, T. R. Bedding, J. De Ridder

The discovery of solar-like oscillations in the giant star xy Hya (G7III) was reported by Frandsen et al. (2002). Their frequency analysis was very limited due to alias problems in the data set (caused by single-site observations). The extent to which the aliasing affected their analysis was unclear due to the unknown damping time of the stellar oscillation

R. K. S. Yadav, Ram Sagar

In this paper we present UBVRI CCD photometry in the region of two young open star clusters Basel 4 and NGC 7067 for the first time. Our sample consists of ~ 4000 stars down to V ~ 21 mag. Stellar surface density profile indicates that radius of Basel 4 and NGC 7067 are about 1.8 and 3.0 arcmin respectively.The (U-B) versus (B-V) diagrams indicate that metal

M. H. Chan, M. C. Chu

Recent Strong lensing data and rotation curves of dwarf galaxies indicate that many galactic clusters may have a soft core instead of a central cusp in their density distribution. This result challenges the standard CDM (Cold Dark Matter) theory prediction based on N-body simulations. We find that the observed density profile is consistent with that of a sph

Christopher W. Mauche, Duane A. Liedahl, Benjamin F. Mathiesen, Mario A. Jimenez-Garate

By means of a Monte Carlo code that accounts for Compton scattering and photoabsorption followed by recombination, we have investigated the radiation transfer of Ly alpha, He alpha, and recombination continua photons of H- and He-like C, N, O, and Ne produced in the photoionized atmosphere of a relativistic black hole accretion disk. We find that photoelectr

Jacco Vink, Johan Bleeker, Jelle Kaastra, Andrew Rasmussen

We present a preliminary analysis of XMM-Newton observations of the oxygen-rich supernova remnant G292.0+1.8 (MSH 11-54). Although the spatial extent of the remnant is 8 arcmin the bright central bar is narrow (1&#39;-2&#39;) resulting in RGS spectra of a high spectral quality. This allows us to spectroscopically identify a cool, Te = 0.3 keV, and underioniz

David S. Meier, Jean L. Turner

We present high resolution (~5&#39;&#39;) maps of the J = 1 - 0 transitions of ^{13}CO and C^{18}O towards the nucleus of NGC 6946, made with the Owens Valley Millimeter Array. The images are compared with existing ^{12}CO(1-0) maps to investigate localized changes in gas properties across the nucleus. As compared to ^{12}CO, both ^{13}CO and C^{18}O are mor

Denis Gonta

The gravitational equations of the 5-dimensional analogue of the AdSS space-time, where all the matter fields are confined on the 3-brane are examined. The most general solutions are established in the generic case of a non-Z_2-symmetric bulk. Constraining these solutions we derive a number of remarkable metrics widely investigated in the literature. Finally

Rodrigo Olea

The thin shell collapse leading to the formation of charged rotating black holes in three dimensions is analyzed in the light of a recently developed Hamiltonian formalism for these systems. It is proposed to demand, as a way to reconcile the properties of an infinitely extended solenoid in flat space with a magnetic black hole in three dimensions, that the

Vyacheslav S. Rychkov

The problem of black hole production in transplanckian particle collisions is revisited, in the context of large extra dimensions scenarios of TeV-scale gravity. The validity of the standard description of this process (two colliding Aichelburg-Sexl shock waves in classical Einstein gravity) is questioned. It is observed that the classical spacetime has larg

Christoph Durr, Mark Heiligman, Peter Hoyer, Mehdi Mhalla

Quantum algorithms for graph problems are considered, both in the adjacency matrix model and in an adjacency list-like array model. We give almost tight lower and upper bounds for the bounded error quantum query complexity of Connectivity, Strong Connectivity, Minimum Spanning Tree, and Single Source Shortest Paths. For example we show that the query complex

Thomas E. Browder, Igor R. Klebanov, Daniel R. Marlow

Following Rosner [hep-ph/0312269], we consider B-decay production channels for the exotic I=0 and $I=3/2$ pentaquarks that have been recently reported. We also discuss new search channels for isovector pentaquarks, such as the $Θ^{*++} (\bar s duuu)$, that are generically present in chiral soliton models but were not observed in recent experiments. Futhermor

D. Lazzati, S. Covino, J. Gorosabel, E. Rossi

The polarization curve of GRB 020813 is discussed and compared to different models for the structure, evolution and magnetisation properties of the jet and the interstellar medium onto which the fireball impacts. GRB 020813 is best suited for this kind of analysis for the smoothness of its afterglow light curve, ensuring the applicability of current models.

A. L. Chudnovskiy

Phononless plasmon assisted thermally activated transport through a long disordered array of finite length quantum wires is investigated analytically. Generically strong electron plasmon interaction in quantum wires results in a qualitative change of the temperature dependence of thermally activated resistance in comparison to phonon assisted transport. At h

Aaron LaCluyze, Horace A. Smith, E. -M. Gill, A. Hedden

New CCD photometry has been obtained for the RR Lyrae variable star XZ Cygni. An analysis of old and new photometry confirms earlier results that XZ Cygni exhibits the Blazhko Effect and that its Blazhko period has changed over time. These changes in the Blazhko period are anticorrelated with observed changes in the primary period of XZ Cygni. During the fir

Steven Weinberg

It is shown that non-adiabatic cosmological perturbations cannot arise during the period of reheating following inflation with a single scalar inflaton field.

Louis H. Kauffman, Samuel J. Lomonaco

This paper explores of the role of unitary braiding operators in quantum computing. We show that a single specific solution R (the Bell basis change matrix) of the Yang-Baxter Equation is a universal gate for quantum computing, in the presence of local unitary transformations. We show that this same R generates a new non-trivial invariant of braids, knots, a

R. Vanderspek, T. Sakamoto, C. Barraud, T. Tamagawa

An exceptionally intense gamma-ray burst, GRB030329, was detected and localized by the instruments on board the High Energy Transient Explorer satellite (HETE) at 11:37:14 UT on 29 March 2003. The burst consisted of two \~10s pulses of roughly equal brightness and an X-ray tail lasting >100s. The energy fluence in the 30-400 keV energy band was 1.08e-4 erg/c

C. J. Milne, D. N. Argyriou, A. Chemseddine, N. Aliouane

We have studied the superconducting phase diagram of \NaH\space as a function of electronic doping, characterizing our samples both in terms of Na content $x$ and the Co valence state. Our findings are consistent with a recent report that intercalation of \oxp\space ions into Na$_{x}$CoO$_{2}$, together with water, act as an additional dopant indicating that

Veniamin S. Berezinsky, Vyacheslav I. Dokuchaev

We describe the formation of a seed massive black hole (MBH) inside a supermassive star (SMS) in a distant galactic nucleus. The short-lived SMS is naturally formed due to collision destructions of normal stars in the evolving galactic nucleus. The neutron stars (NSs) and stellar-mass black holes form a compact self-gravitating subsystem deep inside a SMS. T

A. S. Alexandrov, V. N. Zavaritsky

We calculate the Nernst signal in disordered conductors with the chemical potential near the mobility edge. The Nernst effect originates from interference of itinerant and localised-carrier contributions to the thermomagnetic transport. It reveals a strong temperature and magnetic field dependence, which describes quantitatively the anomalous Nernst signal i

J. E. Sonier, F. D. Callaghan, R. I. Miller, E. Boaknin

We report muon spin rotation measurements on the conventional type-II superconductor V3Si that provide clear evidence for changes to the inner structure of a vortex due to the delocalization of bound quasiparticle core states. The experimental findings described here confirm a key prediction of recent microscopic theories describing interacting vortices. The

Jesus Gomez-Gardenes, Yamir Moreno

The scale-free model of Barabasi and Albert gave rise to a burst of activity in the field of complex networks. In this paper, we revisit one of the main assumptions of the model, the preferential attachment rule. We study a model in which the PA rule is applied to a neighborhood of newly created nodes and thus no global knowledge of the network is assumed. W

David T. Gay, Robion Kirby

Given a smooth, closed, oriented 4-manifold X and alpha in H_2(X,Z) such that alpha.alpha > 0, a closed 2-form w is constructed, Poincare dual to alpha, which is symplectic on the complement of a finite set of unknotted circles. The number of circles, counted with sign, is given by d = (c_1(s)^2 -3sigma(X) -2chi(X))/4, where s is a certain spin^C structure n

Yamir Moreno, Amalio F. Pacheco

In this work, we study the synchronization of coupled phase oscillators on the underlying topology of scale-free networks. In particular, we assume that each network&#39;s component is an oscillator and that each interacts with the others following the Kuramoto model. We then study the onset of global phase synchronization and fully characterize the system&#

M. Mignoli, L. Pozzetti, A. Comastri, M. Brusa

We present the results of deep near-infrared observations of 11 hard X-ray selected sources in the Hellas2XMM survey, with faint optical magnitude (R>24) and high X-ray-to-optical flux ratio. All but one of the sources have been detected in the Ks band, with bright counterparts (Ks<19) and red colors (R-K>5), and therefore belong to the ERO population. A det

Gerard Duchamp, Hatem Hadj Kacem, Eric Laugerotte

We present here algebraic formulas associating a k-automaton to a k-epsilon-automaton. The existence depends on the definition of the star of matrices and of elements in the semiring k. For this reason, we present the theorem which allows the transformation of k-epsilon-automata into k-automata. The two automata have the same behaviour.

Yu. S. Surovtsev, T. D. Blokhintseva, P. Bydzovsky, M. Nagy

Methods are set forth for determining the hadron electromagnetic structure in the sub-$N\bar{N}$-threshold timelike region of the virtual-photon ``mass&#39;&#39; and for investigating the nucleon weak structure in the spacelike region from experimental data on the process $πN\to e^+e^- N$ at low energies. These methods are formulated using the unified descri