July 2003 arXiv papers — page 6

Maciej M. Duras

The random matrix ensembles (RME) of quantum statistical Hamiltonians, e.g. Gaussian random matrix ensembles (GRME) and Ginibre random matrix ensembles (Ginibre RME), are applied in literature to following quantum statistical systems: molecular systems, nuclear systems, disordered materials, random Ising spin systems, and two-dimensional electron systems (Wi

I. Schnell, G. Czycholl, R. C. Albers

Unscreened Hartree-Fock approximation (HFA) calculations for metallic Fe, Co, Ni, and Cu are presented, by using a quantum-chemical approach. We believe that these are the first HFA results to have been done for crystalline 3d transition metals. Our approach uses a linearized muffin-tin orbital calculation to determine Bloch functions for the Hartree one-par

Nurit Baytch, Robin L. B. Selinger, Jonathan V. Selinger, R. Shashidhar

In bulk ferroelectric liquid crystals, the molecular director twists in a helix. In narrow cells, this helix can be unwound by an applied electric field or by boundary effects. To describe helix unwinding as a function of both electric field and boundary effects, we develop a mesoscale simulation model based on a continuum free energy discretized on a two-di

Luciano Rezzolla, Shin'ichirou Yoshida, Olindo Zanotti

This is the first of a series of papers investigating the oscillation properties of relativistic, non-selfgravitating tori orbiting around a black hole. In this initial paper we consider the axisymmetric oscillation modes of a torus constructed in a Schwarzschild spacetime. To simplify the treatment and make it as analytical as possible, we build our tori wi

Luciano Rezzolla, Shin'ichirou Yoshida, Thomas J. Maccarone, Olindo Zanotti

Observations of X-ray emissions from binary systems have long since been considered important tools to test General Relativity in strong-field regimes. The high frequency quasi-periodic oscillations (HFQPOs) observed in binaries containing a black hole candidate, in particular, have been proposed as a means to measure more directly the black hole properties

Lev Titarchuk, Demos Kazanas, Peter A. Becker

We formulate and solve the diffusion problem of line photon propagation in a bulk outflow from a compact object (black hole or neutron star) using a generic assumption regarding the distribution of line photons within the outflow. Thomson scattering of the line photons within the expanding flow leads to a decrease of their energy which is of first order in v

D. Fargion

High Energy Neutrino Astronomy energy windows may be ruled by a new Upward and Horizontal Tau Air-Showers (UpTaus, HorTaus) detectors (scintillators and optical arrays) located a few kilometers beyond facing High Mountains Chains, or located above their top or flying on Planes, on Balloons and on Satellites facing downward to the Earth Crust Horizon. While l

Michiel R. Hogerheijde, Doug Johnstone, Isamu Matsuyama, Ray Jayawardhana

We report detection of continuum emission at 850 and 450 micron from disks around four Classical T Tauri stars in the MBM 12 (L1457) young association. Using a simple model we infer masses of 0.0014-0.012 M_sun for the disk of LkHa 263 ABC, 0.005-0.021 M_sun for S18 ABab, 0.03-0.18 M_sun for LkHa 264 A, and 0.023-0.23 M_sun for LkHa 262. The disk mass found

M. Odenkirchen, E. K. Grebel

The distribution of stars in the outer part of the sparse globular cluster NGC 5466 provides evidence for possible tidal mass loss after a recent disk-shock near the solar circle.

S. Andreon

We studied the homogeneity, across clusters, of the color of the red sequence (the intercept of the color--magnitude relation) of 158 clusters and groups detected in the Early Data Release of the Sloan Digital Sky Survey (EDR-SDSS) in the redshift range 0.06<z<0.34. We found a high degree of homogeneity: the color of the red sequence shows an intrinsic scatt

Spyridon Kitsionas

We have invented a new algorithm to use with self-gravitating SPH Star Formation codes. The new method is designed to enable SPH simulations to self-regulate their numerical resolution, i.e. the number of SPH particles; the latter is calculated using the Jeans condition (Bate & Burkert 1997) and the local hydrodynamic conditions of the gas. We apply our SPH

Hector De Vega

This is a pedagogical introduction to early cosmology and the host of fundamental physics involved in it (particle physics, grand unification and general relativity). Inflation and the inflaton field are the central theme of this review. The quantum field treatment of the inflaton is presented including its out of equilibrium evolution and the use of nonpert

B. Tingley

In Tingley (2003), all available transit detection algorithms were compared in a simple, rigorous test. However, the implementation of the Box-fitting Least Squares (BLS) approach of Kovacs et al. (2002) used in that paper was not ideal for those purposes. This letter revisits the comparison, using a version of the BLS better suited to the task at hand and m

Ralph Neuh&#34;auser, E. W. Guenther, J. Alves, N. Huelamo

We present deep high dynamic range infrared images of young nearby stars in the Tucana/Horologium and beta Pic associations, all ~ 10 to 35 Myrs young and at ~10 to 60 pc distance. Such young nearby stars are well-suited for direct imaging searches for brown dwarf and even planetary companions, because young sub-stellar objects are still self-luminous due to

A. N. Parmar, E. Kuulkers, T. Oosterbroek, P. Barr

INTEGRAL made 3 observations in 2003 April of the black hole candidate H 1743-322 during the rising part, and close to the maximum, of an outburst. H 1743-322 was previously observed in outburst in 1977-1978. The source is located in a crowded region of the sky (l = 357 deg, b = -2 deg) and at least 18 sources are clearly detected in the field of view of the

Patrick A. Woudt, Brian Warner

High speed photometry of the new AM CVn star in Hya (previously known as SN2003aw), spectroscopically identified by Chornock & Filippenko, shows it to have a superhump period of 2041.5 +/- 0.3 s. We find a range of brightness from V ~ 16.5 to 20.3, presumably caused by variations in the rate of mass transfer. In the intermediate state the system cycles in br

A. L. Longinotti, M. Cappi, K. Nandra, M. Dadina

The observation of the Narrow-Line Seyfert 1 galaxy IRAS13349+2438 performed by XMM-Newton European Photon Imaging Camera between 0.3-10 keV, is presented here. The broadband spectrum of the source is dominated at low energies (E < 2 keV) by a strong excess of emission and by complex emission/absorption features between 5.5-8.0 keV. The soft X-ray spectrum i

Jairo Sinova, Dimitrie Culcer, Q. Niu, N. A. Sinitsyn

We describe a new effect in semiconductor spintronics that leads to dissipationless spin-currents in paramagnetic spin-orbit coupled systems. We argue that in a high mobility two-dimensional electron system with substantial Rashba spin-orbit coupling, a spin-current that flows perpendicular to the charge current is intrinsic. In the usual case where both spi

Christian D. Ott, Adam Burrows, Eli Livne, Rolf Walder

We have carried out an extensive set of two-dimensional, axisymmetric, purely-hydrodynamic calculations of rotational stellar core collapse with a realistic, finite-temperature nuclear equation of state and realistic massive star progenitor models. For each of the total number of 72 different simulations we performed, the gravitational wave signature was ext

Henrik Omma, James Binney, Greg Bryan, Adrianne Slyz

Active galactic nuclei are clearly heating gas in `cooling flows&#39;. The effectiveness and spatial distribution of the heating are controversial. We use three-dimensional simulations on adaptive grids to study the impact on a cooling flow of weak, subrelativistic jets. The simulations show cavities and vortex rings as in the observations. The cavities are

Javid A. Sheikh, Yang Sun

The onset of chaos and the mechanism of rotational damping are studied in an exactly soluble particle-rotor model. It is shown that the degree of chaoticity as inferred from the statistical measures is closely related to the onset of rotational damping obtained using the model Hamiltonian.

G. H. Bordbar

We have studied the influences of isospin symmetry breaking of nucleon-nucleon interaction on the various properties of asymmetrical nuclear matter and $β$-stable matter. For asymmetrical nuclear matter, it is found that by including this isospin symmetry breaking, the changes of bulk properties increase by increasing both density and asymmetry parameter. Ho

Viacheslav V. Nikulin

Let X be a K3 surface with a polarization H with H^2=2rs. Assume that H.N(X)=Z for the Picard lattice N(X). The moduli space Y of sheaves over X with the Mukai vector (r,H,s) is again a K3 surface. We prove that Y\cong X, if there exists h_1\in N(X) with (h_1)^2=f(r,s), H.h_1\equiv 0\mod g(r,s), and h_1 satisfies some condition of primitivity. Existence of s

Chan-Gyung Park

We present results from a test for the Gaussianity of the whole sky sub-degree scale CMB temperature anisotropy measured by the Wilkinson Microwave Anisotropy Probe (WMAP). We calculate the genus from the foreground-subtracted and Kp0-masked WMAP maps and measure the genus shift parameters defined at negative and positive threshold levels and the asymmetry p

Yu Tian

The Drinfeld-Manin construction of U(N) instanton is reformulated in the ADHM formulism, which gives explicit general solutions of the ADHM constraints for U(N) (N>=2k-1) k-instantons. For the N<2k-1 case, implicit results are given systematically as further constraints, which can be used to the collective coordinate integral. We find that this formulism can

V. M. Bystritsky, V. F. Boreiko, M. Filipowicz, V. V. Gerasimov

The paper describes an experiment aimed at studying muon capture by ${}^{3}\mathrm{He}$ nuclei in pure ${}^{3}\mathrm{He}$ and $\mathrm{D}_2 + {}^{3}\mathrm{He}$ mixtures at various densities. Energy distributions of protons and deuterons produced via $μ^-+{}^{3}\mathrm{He}\to p+n+n + ν_{μ}$ and $μ^-+{}^{3} \mathrm{He} \to d+n + ν_μ$ are measured for the ene

J. Acacio de Barros, J. P. R. F. de Mendonca, N. Pinto-Neto

In this paper we study in details a system of two weakly coupled harmonic oscillators. This system may be viewed as a simple model for the interaction between a photon and a photodetector. We obtain exact solutions for the general case. We then compute approximate solutions for the case of a single photon (where one oscillator is initially in its first excit

M. V. Altaisky

The density matrix formalism which is widely used in the theory of measurements, quantum computing, quantum description of chemical and biological systems always imply the averaging over the states of the environment. In practice this is impossible because the environment $U\setminusS$ of the system $S$ is the complement of this system to the whole Universe

Seiichiro Honjo, Kunihiko Kaneko

Global diffusion of Hamiltonian dynamical systems is investigated by using a coupled standard maps. Arnold web is visualized in the frequency space, using local rotation numbers, while Arnold diffusion and resonance overlaps are distinguished by the residence time distributions at resonance layers. Global diffusion in the phase space is shown to be accelerat

Junho Lee

We explicitly compute family GW invariants of elliptic surfaces for primitive classes. That involves establishing a TRR formula and a symplectic sum formula for elliptic surfaces and then determining the GW invariants using an argument from \cite{ip3}. In particular, as in \cite{bl1}, these calculations also confirm the well-known Yau-Zaslow Conjecture \cite

Wendelin Werner

This paper is based on mini-courses given in July 2003. Its goal is to give a self-contained sketchy and heuristic survey of the recent results concerning conformal restriction, that were initiated in our joint work with Greg Lawler and Oded Schramm, and further investigated in the last year in joint work with Roland Friedrich, Greg Lawler, and by Julien Dub

Pieter Moree, Huib Hommersom

The Ramanujan sum c_n(k) and a_n(k), the kth coefficient of the nth cyclotomic polynomial, are completely symmetric expressions in terms of primitive nth roots of unity. For fixed k we study the value distribution of c_n(k) (following A. Wintner) and a_n(k) (partly following H. Moller). In particular we disprove a 1970 conjecture of H. Moller on the average

Raphael Yuster

Let ${\cal F}$ be a family of graphs. For a graph $G$, the {\em ${\cal F}$-packing number}, denoted $ν_{\cal F}(G)$, is the maximum number of pairwise edge-disjoint elements of ${\cal F}$ in $G$. A function $ψ$ from the set of elements of ${\cal F}$ in $G$ to $[0,1]$ is a {\em fractional ${\cal F}$-packing} of $G$ if $\sum_{e \in H \in {\cal F}} {ψ(H)} \leq

Junho Lee

The usual Gromov-Witten invariants are zero for Kähler surfaces with $p_g\geq 1$. In this paper we use analytic methods to define Family Gromov-Witten Invariants for Kähler surfaces. We prove that these are well-defined invariants of the deformation class of the Kähler structure.

A. T. Filippov

A new class of integrable theories of 0+1 and 1+1 dimensional dilaton gravity coupled to any number of scalar fields is introduced. These models are reducible to systems of independent Liouville equations whose solutions must satisfy the energy and momentum constraints. The constraints are solved thus giving the explicit analytic solution of the theory in te

Daniel Brace, Carlos A. R. Herdeiro, Shinji Hirano

We consider Neveu-Schwarz pp-waves with spacetime supersymmetry. Upon compactification of a spacelike direction, these backgrounds develop Closed Null Curves (CNCs) and Closed Timelike Curves (CTCs), and are U-dual to supersymmetric Godel type universes. We study classical and quantum strings in this background, with emphasis on the strings winding around th

J. Ambjorn, J. Jurkiewicz, R. Loll

Lorentzian simplicial quantum gravity is a non-perturbatively defined theory of quantum gravity which predicts a positive cosmological constant. Since the approach is based on a sum over space-time histories, it is perturbatively non-renormalizable even in three dimensions. By mapping the three-dimensional theory to a two-matrix model with ABAB interaction w

M. G. Ivanov

The generally adopted approach in theory of relativistic strings and membranes, is similar to use of Lagrange coordinates in continious media mechanics. One can use an alternative approach, which is similar to use of Euler coordinates. Under such approach the consideration of thick (delocalized) membranes is natural. Membrane kinematics, which coorespond to

Hitoshi Murayama

Technicolor achieves electroweak symmetry breaking (EWSB) in an elegant and natural way, while it suffers from severe model building difficulties. I propose to abandon its secondary goal to eliminate scalar bosons in exchange of solving numerous problems using supersymmetry. It helps to understand walking dynamics much better with certain exact results. In t

Vera G. Luth

A preliminary measurement of the second moments of the hadron mass in B --> X l nu decays by the BABAR Collaboration is reported. These measurements are performed as a function of the lepton momentum above a given threshold.

Nguyen Hong Quang, Tran The Trung, Johann See, Philippe Dollfus

We present an exact calculation of the single-electron energies and wave-functions for any bound state in a realistic Si-SiO2 spherical quantum dot, including the material dependence of the electron effective mass. The influence of dot radius, confinement barrier potential and barrier-to-dot electron mass ratio on the electronic structure is investigated in

M. Braden, P. Steffens, Y. Sidis, J. Kulda

The anisotropy of the magnetic incommensurate fluctuations in Sr2RuO4 has been studied by inelastic neutron scattering with polarized neutrons. We find a sizeable enhancement of the out of plane component by a factor of two for intermediate energy transfer which appears to decrease for higher energies. Our results qualitatively confirm calculations of the sp

Debangshu Chaudhuri, Ashwani Kumar, D. D. Sarma, M. Garcia-Hernandez

We show that newly found BF3-doped polyaniline, though highly conducting, remains amorphous. Magnetic studies reveal many unusual properties, while suggesting that the intrinsic conductivity of this system is significantly larger than all other known forms of conducting polyaniline, establishing it as an interesting class of highly conducting amorphous polym

Alberto Conti, Andrew J. Connolly, Andrew M. Hopkins, Tamas Budavari

We analyze the photometric information contained in individual pixels of galaxies in the Hubble Deep Field North (HDFN) using a new technique, _pixel-z_, that combines predictions of evolutionary synthesis models with photometric redshift template fitting. Each spectral energy distribution template is a result of modeling of the detailed physical processes a

M. Bailes, S. M. Ord, H. S. Knight, A. W. Hotan

Here we report timing measurements of the relativistic binary pulsar PSR J1141-6545 that constrain the component masses and demonstrate that the orbital period derivative \dot Pb = (-4+/-1)x10^-13 is consistent with gravitational wave emission as described by the general theory of relativity. The mass of the neutron star and its companion are 1.30+/-0.02 Mo

Ehud Behar, Andrew P. Rasmussen, Alexander J. Blustin, Masao Sako

A long 280 ks observation of the Seyfert 1 galaxy NGC 3783 with XMM-Newton is reported. We focus on the oxygen line complex between 17 and 24 A as measured with the RGS spectrometers. Accurate absorption column densities and emission line fluxes are obtained. We explore several options for the geometry and physical form of the emitting and absorbing gas. The

Yu-Qing Lou, Zhuhui Fan

Multi-wavelength observations from radio to soft X-ray bands of large-scale galactic spiral structures offer synthesized and comprehensive views of nearby disk galaxies. In the presence of a massive dark-matter halo, the density-wave dynamics on galactic scales involves the stellar disk, the gas disk of interstellar medium (ISM), the magnetic field, and the

Craig C. Wiegert

Cosmologically distributed compact dark matter objects with masses in the approximate range of 0.001 to 1 solar masses can amplify the continuum emission of a quasar through gravitational microlensing, without appreciably affecting its broad emission lines. This will produce a statistical excess of weak-lined quasars in the observed distribution of spectral

C. -T. Chen, N. -C. Yeh

The energy, momentum and temperature dependence of the quasiparticle local density of states (LDOS) of a two-dimensional $d_{x^2-y^2}$-wave superconductor with random disorder is investigated using the first-order T-matrix approximation. The results suggest that collective modes such as spin/charge density waves are relevant low-energy excitations of the cup

K. Desch, A. Imhof, Z. Was, M. Worek

The prospects for the measurement of the pseudoscalar admixture in the h-tau-tau coupling to a Standard Model Higgs boson of 120 GeV mass are discussed in a quantitative manner e+ e- collisions of 350 GeV centre-of-mass energy. Specific angular distributions in the h --> tau tau; tau --> rho nu decay chain can be used to probe mixing angles of scalar--pseudo

K. Thirulogasanthar, G. Honnouvo

The canonical coherent states are expressed as infinite series in powers of a complex number $z$ in their infinite series version. In this article we present classes of coherent states by replacing this complex number $z$ by other choices, namely, iterates of a complex function, higher functions and elementary functions. Further, we show that some of these c

N. C. Tsamis, R. P. Woodard

We recently derived exact solutions for the scalar, vector and tensor mode functions of a single, minimally coupled scalar plus gravity in an arbitrary homogeneous and isotropic background. These solutions are applied to obtain improved estimates for the primordial scalar and tensor power spectra of anisotropies in the cosmic microwave background.

J. Yoo

A search for periodic modulations of the solar neutrino flux was performed using the Super-Kamiokande-I data taken from May 31st, 1996 to July 15th, 2001. The detector&#39;s capability of measuring the exact time of events, combined with a relatively high yield of solar neutrino events, allows a search for short-time variations in the observed flux. We emplo

Lilia Anguelova, Pietro A. Grassi

Recently a new formalism has been developed for the covariant quantization of superstrings. We study properties of Dp-branes and p-branes in this new framework, focusing on two different topics: effective actions and boundary states for Dp-branes. We present a derivation of the Wess-Zumino terms for super (D)p-branes using BRST symmetry. To achieve this we d

Makoto Matsumiya, Kunihito Ioka

We investigate the circular polarization (CP) from Gamma-Ray Burst (GRB) afterglows. We show that a tangled magnetic field cannot generate CP without an ordered magnetic field because there is always an oppositely directed field, so that no handedness exists. This implies the observation of CP could be a useful probe of an ordered field, which carries valuab

O. E. Barndorff-Nielsen, R. D. Gill, P. E. Jupp

Interest in problems of statistical inference connected to measurements of quantum systems has recently increased substantially, in step with dramatic new developments in experimental techniques for studying small quantum systems. Furthermore, theoretical developments in the theory of quantum measurements have brought the basic mathematical framework for the

O. E. Barndorff-Nielsen, R. D. Gill, P. E. Jupp

Recent developments in the mathematical foundations of quantum mechanics have brought the theory closer to that of classical probability and statistics. On the other hand, the unique character of quantum physics sets many of the questions addressed apart from those met classically in stochastics. Furthermore, concurrent advances in experimental techniques an

J. Froehlich, M. Griesemer, B. Schlein

Scattering in a model of a massive quantum-mechanical particle, an ``electron&#39;&#39;, interacting with massless, relativistic bosons, ``photons&#39;&#39;, is studied. The interaction term in the Hamiltonian of our model describes emission and absorption of ``photons&#39;&#39; by the ``electron&#39;&#39;; but ``electron-positron&#39;&#39; pair production i

Jesus De Loera, David Haws, Raymond Hemmecke, Peter Huggins

We encode the binomials belonging to the toric ideal $I_A$ associated with an integral $d \times n$ matrix $A$ using a short sum of rational functions as introduced by Barvinok \cite{bar,newbar}. Under the assumption that $d,n$ are fixed, this representation allows us to compute the Graver basis and the reduced Gröbner basis of the ideal $I_A$, with respect

Konstanze Rietsch

These notes aim to give a first introduction to intersection cohomology and perverse sheaves with applications to representation theory or quantum groups in mind.

A. A. Saharian, E. R. Bezerra de Mello

We investigate the vacuum expectation values of the energy-momentum tensor and the fermionic condensate associated with a massive spinor field obeying the MIT bag boundary condition on a spherical shell in the global monopole spacetime. In order to do that it was used the generalized Abel-Plana summation formula. As we shall see, this procedure allows to ext

Michael J. W. Hall, Kailash Kumar, Marcel Reginatto

A Hamiltonian formalism is used to describe ensembles of fields in terms of two canonically conjugate functionals (one being the field probability density). The postulate that a classical ensemble is subject to nonclassical fluctuations of the field momentum density, of a strength determined solely by the field uncertainty, is shown to lead to a unique modif

H. V. Klapdor-Kleingrothaus

The first evidence for neutrinoless double beta decay has been observed in the HEIDELBERG-MOSCOW experiment, which is the most sensitive double beta decay experiment since ten years. This is the first evidence for lepton number violation and proves that the neutrino is a Majorana particle. It further shows that neutrino masses are degenerate. In addition it

Hans Volker Klapdor-Kleingrothaus

On May 5, 2003 in the GRAN SASSO Underground Laboratory the first naked high-purity Germanium detectors were installed successfully in liquid nitrogen in the GENIUS-Test-Facility (GENIUS-TF). This is the first time ever that this novel technique for extreme background reduction in searches for rare decays is going to be tested under realistic background cond

Qing-hua Xu, Zuo-tang Liang

We argue that spin alignment of the vector mesons observed in unpolarized hadron-hadron collisions is closely related to the single spin left-right asymmetry observed in transversely polarized hadron-hadron collisions. We present the numerical results obtained from the type of spin-correlation imposed by the existence of the single-spin left-right asymmetrie

V. Schatz

This thesis comprises two investigations, both connected with the attempt to understand Regge theory in the framework of QCD. The first is about how the odderon, a Reggeon carrying no charge which is odd under charge conjugation, couples to the proton. The second concerns unitarity corrections to the BFKL equation which describes the pomeron, a Reggeon with

P. J. Bussey

A brief survey is given of recent HERA results in jet production and prompt photon production, together with the evaluation of the QCD coupling constant alpha_s.

P. J. Bussey

An overview is given of the ongoing measurement at HERA of the parton structure of the photon, as a function of its virtuality. Preliminary ZEUS results show disagreement with an NLO QCD calculation.

Sergiu Vacaru, D. E. Goksel

The horizon and geodesic structure of static configurations generated by anisotropic conformal transforms of the Schwarzschild metric is analyzed. We construct the maximal analytic extension of such off--diagonal vacuum metrics and conclude that for small deformations there are different classes of vacuum solutions of the Einstein equations describing &#34;b

Scott B. Guthery

A group authentication protocol authenticates pre-defined groups of individuals such that: - No individual is identified - No knowledge of which groups can be successfully authenticated is known to the verifier - No sensitive data is exposed The paper presents a group authentication protocol based on splitting the private keys of the Naccache-Stern public-ke

W. Fenz, R. Folk, I. M. Mryglod, I. P. Omelyan

The influence of an external magnetic field on the liquid-gas phase transition in Ising, XY, and Heisenberg spin fluid models is studied using a modified mean field theory and Gibbs ensemble Monte Carlo simulations. It is demonstrated that the theory is able to reproduce quantitatively all characteristic features of the field dependence of the critical tempe

A. V. Shavrina, N. S. Polosukhina, Ya. V. Pavlenko, A. V. Yushchenko

We carried out a detailed analysis of spectra of the unique roAp star HD 101065 (Przybylski&#39;s star) near the resonance doublet Li I 6708 A, using a most complete line list including all possible transitions between REE levels of NIST database. Our model calculations were performed under two assumptions: blend of Li and REE lines, and blend of REE lines o

Hee-Jong Seo, Daniel J. Eisenstein

We show that the measurement of the baryonic acoustic oscillations in large high redshift galaxy surveys offers a precision route to the measurement of dark energy. The cosmic microwave background provides the scale of the oscillations as a standard ruler that can be measured in the clustering of galaxies, thereby yielding the Hubble parameter and angular di

Peter Arnold, Jonathan Lenaghan, Guy D. Moore

We study the role of QCD plasma instabilities in non-equilibrium quark-gluon plasmas. First, we argue that such instabilities must drastically modify the "bottom-up" thermalization scenario for heavy-ion collisions. Second, we discuss conditions for the existence of instabilities in a more general context than previously treated in the QCD literature. We als

John A. Tomsick, Emrah Kalemci, Philip Kaaret

Using the Chandra X-ray Observatory and the Rossi X-ray Timing Explorer, we have studied the black hole candidate (BHC) X-ray transient XTE J1650-500 near the end of its 2001-2002 outburst after its transition to the low-hard state at X-ray luminosities down to L = 1.5E34 erg/s (1-9 keV, assuming a source distance of 4 kpc). Our results include a characteriz

A. J. R. Sanderson, T. J. Ponman

We investigate the spatial distribution of the baryonic and non-baryonic mass components in a sample of 66 virialized systems. We have used X-ray measurements to determine the deprojected temperature and density structure of the intergalactic medium and have employed these to map the underlying gravitational potential. In addition, we have measured the depro

Jonathan C. Tan, Eric G. Blackman

Are magnetic fields important in primordial star formation? Assuming that star formation occurs via an accretion disk that is turbulent, initially because of local gravitational instability, we calculate the disk structure for realistic accretion rates. We predict that local gravitational viscosity is able to drive accretion, without the disk fragmenting. We

Veronika E. Hubeny, Mukund Rangamani, Simon F. Ross

We investigate the appearance of closed timelike curves in quotients of plane waves along spacelike isometries. First we formulate a necessary and sufficient condition for a quotient of a general spacetime to preserve stable causality. We explicitly show that the plane waves are stably causal; in passing, we observe that some pp-waves are not even distinguis

A. Nicolaidis, N. G. Sanchez

In TeV scale unification models, gravity propagates in 4+d dimensions while gauge and matter fields are confined to a four dimensional brane, with gravity becoming strong at the TeV scale. For a such scenario, we study strong gravitational interactions in a effective Schwarzschild geometry. Two regimes appear. For large impact parameters, the ratio rho=(Rs/r

G. Fritz Benedict, B. E. McArthur, L. W. Fredrick, T. E. Harrison

We present an absolute parallax and relative proper motion for the central star of the planetary nebula NGC 6853 (The Dumbell). We obtain these with astrometric data from FGS 3, a white-light interferometer on {\it HST}. Spectral classifications and VRIJHKT$_2$M and DDO51 photometry of the stars comprising the astrometric reference frame provide spectrophoto

Jaiyul Yoo, Julio Chaname, Andrew Gould

We simulate the evolution of halo wide binaries in the presence of MAssive Compact Halo Objects (MACHOs) and compare our results to the sample of wide binaries of Chaname & Gould (2003). The observed distribution is well fit by a single power law for angular separation, 3.5&#34; < theta < 900&#34;, whereas the simulated distributions show a break in the powe

Minos Axenides, Emmanuel Floratos, Christos Kokorelis

We discuss the first string theory examples of three generation non-supersymmetric SU(5) and {\em flipped} SU(5) GUTS, which break to the Standard model at low energy, without extra matter and/or gauge group factors. Our GUT examples are based on IIA $Z_3$ orientifolds with D6-branes intersecting at non-trivial angles. These theories necessarily satisfy RR t

Hans-Joachim Drescher, Marcus Bleicher, Sven Soff, Horst Stoecker

The influence of high and low energy hadronic models on lateral distribution functions of cosmic ray air showers for AUGER energies is explored. A large variety of presently used high and low energy hadron interaction models are analysed and the resulting lateral distribution functions are compared. We show that the slope as well as the signal at 1000 m dist

Piero Olla, Paolo Paradisi

We propose an alternative interpretation of Markovian transport models based on the well-mixedness condition, in terms of the properties of a random velocity field with second order structure functions scaling linearly in the space time increments. This interpretation allows direct association of the drift and noise terms entering the model, with the geometr

Carlo Angelantonj, Ignatios Antoniadis

We construct non-supersymmetric type I string models which correspond to consistent flat-space solutions of all classical equations of motion. Moreover, the one-loop vacuum energy is naturally fixed by the size of compact extra dimensions which, in the two-dimensional case, can be lowered to a fraction of a millimetre. This class of models has interesting no

A. U. B. Wolter, H. Rakoto, M. Costes, A. Honecker

We present a high-field magnetization study of the $S$ = 1/2 antiferromagnetic Heisenberg chain [PM Cu(NO$_3$)$_2$(H$_2$O)$_2$]$_n$. For this material, as result of the Dzyaloshinskii-Moriya interaction and a staggered $g$ tensor, the ground state is characterized by an anisotropic field-induced spin excitation gap and a staggered magnetization. Our data rev

Ting Gao, Fengli Yan, Zhixi Wang

We present an example of quantum computational tasks whose performance is enhanced if we distribute quantum information using quantum cloning. Furthermore we give achievable efficiencies for probabilistic cloning the quantum states used in implemented tasks for which cloning provides some enhancement in performance.

Aaron Sokasian, Naoki Yoshida, Tom Abel, Lars Hernquist

We combine fast radiative transfer calculations with high resolution hydrodynamical simulations to study an epoch of early hydrogen reionisation by primordial stellar sources at redshifts 15<z<30. With relatively conservative assumptions, population III star formation proceeds in a self-regulated manner both locally and globally and, for a conventional LCDM

E. Christova, E. Ginina, M. Stoilov

The CP violating asymmetry between the partial decay rates of $H^+ \to W^+ h^0$ and $H^- \to W^- h^0$ is calculated at one-loop level in MSSM with complex parameters. The dependence on the phases of $A_τ$ and $M_1$ is discussed. Different values of $\tan β$ are considered. The asymmetry is up to the order of $10^{-2} $.

S. M. Oliveira, R. Santos

Recent results from the DELPHI collaboration led us to review the present bounds on the b&#39; quark mass. We use all available experimental data for m_b&#39; > 96 GeV to constrain the b&#39; quark mass as a function of the Cabibbo-Kobayashi-Maskawa elements in a sequential four generations model. We find that there is still room for a b&#39; with a mass lar

Paolo Lisca, Andras I. Stipsicz

Using contact surgery we define families of contact structures on certain Seifert fibered three-manifolds. We prove that all these contact structures are tight using contact Ozsath-Szabo invariants. We use these examples to show that, given a natural number n, there exists a Seifert fibered three-manifold carrying at least n pairwise non-isomorphic tight, no

Miguel-Angel Sanchis-Lozano

In this work we examine the possible existence of new physics beyond the standard model which could modify the branching fractions of the leptonic (mainly tauonic) decays of bottomonium vector resonances below the $B\bar{B}$ threshold. The decay width is factorized as the product of two pieces: a) the probability of an intermediate pseudoscalar color-singlet

Paolo Ghiggini

In this article we classify up to isotopy tight contact structures on Seifert manifolds over the torus with one singular fibre.

Stefano Bellucci, Corneliu Sochichiu

We search for the possibility to have supersymmetric string bits at finite discretization $J$. From a general setup we find that the string bits can be made supersymmetric modulo a single defect mode which is not expected to have any sensible effect in the continuum limit.

G. Sambandamurthy, L. W. Engel, A. Johansson, D. Shahar

We present the results of an experimental study of superconducting, disordered, thin-films of amorphous Indium Oxide. These films can be driven from the superconducting phase to a reentrant insulating state by the application of a perpendicular magnetic field ($B$). We find that the high-$B$ insulator exhibits activated transport with a characteristic temper

M. Prester, A. Smontara, I. Zivkovic, A. Bilusic

High-resolution ac susceptibility and thermal conductivity measurement on Cu2Te2O5X2(X=Br,Cl) single crystals are reported. For Br-sample, sample dependence prevents to distinguish between possibilities of magnetically ordered and spin-singlet ground states. In Cl-sample a three-dimensional transition at 18.5 K is accompanied by almost isotropic behavior of

J. S. van Zon, F. C. MacKintosh

Motivated by recent experiments reporting non-Gaussian velocity distributions in driven dilute granular materials, we study by numerical simulation the properties of 2D inelastic gases. We find theoretically that the form of the observed velocity distribution is governed primarily by the coefficient of restitution $η$ and $q=N_H/N_C$, the ratio between the a

ZEUS Collaboration, S. Chekanov

Production of D*+/-(2010) mesons in diffractive deep inelastic scattering has been measured with the ZEUS detector at HERA using an integrated luminosity of 82 pb^{-1}. Diffractive events were identified by the presence of a large rapidity gap in the final state. Differential cross sections have been measured in the kinematic region 1.5 < Q^2 < 200 GeV^2, 0.

Shigeaki Yahikozawa

We study the information metric on instanton moduli spaces in two-dimensional nonlinear sigma models. In the CP^1 model, the information metric on the moduli space of one instanton with the topological charge Q=k which is any positive integer is a three-dimensional hyperbolic metric, which corresponds to Euclidean anti--de Sitter space-time metric in three d

Arnab K. Ray, J. K. Bhattacharjee

The inviscid and thin accretion disc is a simple and well understood model system in accretion studies. In this work, modelling such a disc like a dynamical system, we analyse the nature of the fixed points of the stationary solutions of the flow. We show that of the two fixed points, one is a saddle and the other is a centre type point. We then demonstrate,