March 2003 arXiv papers — page 10

Bo Söderberg

We propose and investigate a unifying class of sparse random graph models, based on a hidden coloring of edge-vertex incidences, extending an existing approach, Random graphs with a given degree distribution, in a way that admits a nontrivial correlation structure in the resulting graphs. The approach unifies a number of existing random graph ensembles withi

Anna Carbone, Giuliano Castelli

The Hurst coefficient $H$ of a stochastic fractal signal is estimated using the function $σ_{MA}^2=\frac{1}{N_{max}-n}\sum_{i=n}^{N_{max}} [y(i)-\widetilde{y}_n(i)]^2$, where $\widetilde{y}_n(i)$ is defined as $1/n \sum_{k=0}^{n-1} y(i-k)$, $n$ is the dimension of moving average box and $N_{max}$ is the dimension of the stochastic series. The ability to capt

J. Navarro, J. Fontcuberta, M. Izquierdo, J. Avila

We report here on the electronic structure of electron-doped half-metallic ferromagnetic perovskites such Sr$_{2-x}$La$_x$FeMoO$_6$ ($x$=0-0.6) as obtained from high-resolved valence-band photoemission spectroscopy (PES). By comparing the PES spectra with band structure calculations, a distinctive peak at the Fermi level (E$_F$) with predominantly (Fe+Mo) t$

J. Schlesner, A. Amann, N. B. Janson, W. Just

We present a novel scheme to stabilize high-frequency domain oscillations in semiconductor superlattices by a time-delayed feedback loop. Applying concepts from chaos control theory we propose to control the spatio-temporal dynamics of fronts of accumulation and depletion layers which are generated at the emitter and may collide and annihilate during their t

E. Johnston-Halperin, J. A. Schuller, C. S. Gallinat, T. C. Kreutz

Ferromagnetic semiconductors promise the extension of metal-based spintronics into a material system that combines widely tunable electronic, optical, and magnetic properties. Here, we take steps towards realizing that promise by achieving independent control of electronic doping in the ferromagnetic semiconductor (Ga,Mn)As. Samples are comprised of superlat

A. Löfgren, I. Shorubalko, P. Omling, A. M. Song

Low-temperature experiments are performed on novel nanoscale nonlinear devices (ballistic rectifiers) as well as nano-structured artificial materials, fabricated from an InP/InGaAs quantum well wafer. A DC output is generated between the lower and upper contacts of these devices, when an AC voltage is applied between the left and right contacts. As the tempe

Gen Tatara, N. Garcia

Quantum devices and computers will need operational units in different architectural configurations for their functioning. The unit should be a simple ``quantum toy'', easy to handle superposition states. Here a novel such unit of quantum mechanical flux state (or persistent current) in a conducting ring with three ferromagnetic quantum dots is prese

Heribert Wilhelm

Recent developments of the AC-calorimetric technique adapted for the needs of high pressure experiments are discussed. A semi-quantitative measurement of the specific heat with a Bridgman-type of pressure cell as well as a diamond anvil cell is possible in the temperature range 0.1 K < T < 10 K. The pressure transmitting medium used to ensure good pressure c

Helmut Schiessel

Recent progress has been made in the understanding of the physical properties of chromatin -- the dense complex of DNA and histone proteins that occupies the nuclei of plant and animal cells. Here I will focus on the two lowest levels of the hierarchy of DNA folding into the chromatin complex: (i) the nucleosome, the chromatin repeating unit consisting of a

Dmitri Volchenkov, Philippe Blanchard, Serge Sharoff

We present the new empirical parameter $f_c$, the most probable usage frequency of a word in a language, computed via the distribution of documents over frequency $x$ of the word. This parameter allows for filtering the core lexicon of a language from the content words, which tend to be extremely frequent in some texts written in specific genres or by certai

Ludovic Berthier

The existence of a generalized fluctuation-dissipation theorem observed in simulations and experiments performed in various glassy materials is related to the concepts of local equilibration and heterogeneity in space. Assuming the existence of a dynamic coherence length scale up to which the system is locally equilibrated, we extend previous generalizations

Ludovic Berthier

We show that finite size scaling techniques can be employed to study the glass transition. Our results follow from the postulate of a diverging correlation length at the glass transition whose physical manifestation is the presence of dynamical heterogeneities. We introduce a parameter B(T,L) whose temperature, T, and system size, L, dependences permit a pre

Ludovic Berthier, Juan P. Garrahan

We show that the dynamics between inherent structures in glass forming systems can be understood in purely dynamical terms, without any reference to ``topographic&#39;&#39; features of the potential energy landscape. This ``non-topographic&#39;&#39; interpretation is based instead on the existence of dynamical heterogeneities and on their statistical propert

Sumedha, Deepak Dhar

We relate $ϕ(\bf{x},s)$, the average number of sites at a transverse distance $\bf{x}$ in the directed animals with $s$ sites in $d$ transverse dimensions, to the two-point correlation function of a lattice gas with nearest neighbor exclusion in $d$ dimensions. For large $s$, $ϕ(\bf{x},s)$ has the scaling form $\frac{s}{R_s^d} f(|\bf{x}|/R_s)$, where $R_s$ i

J. Stephens, R. K. Kawakami, J. Berezovsky, M. Hanson

We exploit ferromagnetic imprinting to create complex laterally defined regions of nuclear spin polarization in lithographically patterned MnAs/GaAs epilayers grown by molecular beam epitaxy (MBE). A time-resolved Kerr rotation microscope with approximately 1 micron spatial resolution uses electron spin precession to directly image the GaAs nuclear polarizat

Yunkyu Bang, A. V. Balatsky

We study the anomalously large specific heat jump and its systematic change with pressure in CeCoIn$_5$ superconductor. Starting with the general free energy functional of the superconductor for a coupled electron boson system, we derived the analytic result of the specific heat jump of the strong coupling superconductivity occurring in the coupled electron

Alexander A. Zharov, Ilya V. Shadrivov, Yuri S. Kivshar

We analyze nonlinear properties of microstructured materials with negative refraction, the so-called left-handed metamaterials. We consider a two-dimensional periodic structure created by arrays of wires and split-ring resonators embedded into a nonlinear dielectric, and calculate the effective nonlinear electric permittivity and magnetic permeability. We de

Hyun-Tak Kim, Hidetoshi Minami, Hiromoto Uwe

We have studied the temperature dependence of the optical spectra for the CDW gap and optical phonons in a single crystal of BaBiO_3 and a film deposited by laser ablation. The integrated optical conductivity for optical phonons decreases rapidly with increasing temperature above 150 K, while the single-particle excitation across the CDW gap remains constant

Prabal K. Maiti, Yves Lansac, Matthew A. Glaser, Noel A. Clark

We have carried out Monte Carlo simulations of zig-zag shaped molecules where the the molecules is composed of three rigidly linked hard spherocylinder arranged in a zigzag fashion. By varying zigzag angle we have mapped out the whole phase diagram as a function of pressure, molecular density and zigzag angle $Ψ$. For $Ψ$ between $35^0$ and $80^0$ our model

Alejandro Gangui

The potential role of cosmic topological defects has raised interest in the astrophysical community for many years now. In this set of notes, we give an introduction to the subject of cosmic topological defects and some of their possible observable signatures. We begin with a review of the basics of general defect formation and evolution, we briefly comment

D. A. Boboltz, A. L. Fey, K. J. Johnston, M. J. Claussen

We have used the Very Large Array, linked with the Pie Town Very Long Baseline Array antenna, to determine astrometric positions of 19 radio stars in the International Celestial Reference Frame (ICRF). The positions of these stars were directly linked to the positions of distant quasars through phase referencing observations. The positions of the ICRF quasar

J. Garcia-Sanchez, J. M. Paredes, M. Ribo

We present multiepoch Very Large Array (VLA) observations at 1.4 GHz, 4.9 GHz, 8.5 GHz and 14.9 GHz for a sample of eight RS CVn binary systems. Circular polarization measurements of these systems are also reported. Most of the fluxes observed are consistent with incoherent emission from mildly relativistic electrons. Several systems show an increase of the

Sasa Ratkovic, Sharada Iyer Dutta, Madappa Prakash

The differential rates and emissivities of neutrino pairs from an equilibrium plasma are calculated for the wide range of density and temperature encountered in astrophysical systems. New analytical expressions are derived for the differential emissivities which yield total emissivities in full agreement with those previously calculated. The photon and plasm

Mario Livio

The Hubble Space Telescope (HST), in its thirteen years of operation, has allowed us to observe properties of the universe humans have been able, until very recently, to probe only with their thoughts. This review presents a brief summary of a few of the highlights of HST discoveries, discusses their physical implications, and identifies unsolved problems. A

I. A. Grenier

Identifying gamma-ray sources in the Galaxy is hampered by their poor localization, source confusion, and the large variety of potential emitters. Neutron stars and their environment offer various ways to power gamma-ray sources: pulsed emission from the open magnetosphere and unpulsed gamma rays from the wind nebula and from the cosmic rays accelerated in t

I. M. van Bemmel, C. P. Dullemond

Two-dimensional radiative transfer is employed to obtain the broad-band infrared spectrum of active galaxies. In the models we vary the geometry and size of the obscuring medium, the surface density, the opacity and the grain size distribution. Resulting spectral energy distributions are constructed for different orientations of the toroid. Colour-colour com

H. Hirashita, A. Ferrara, K. Wada, P. Richter

To interpret H_2 quasar absorption line observations in Damped Ly-alpha clouds (DLAs), we model the H_2 spatial distribution within a DLA. Based on numerical simulations of disk structures with parameters similar to those derived for such absorbers, we calculate the H_2 distribution as a function of ultraviolet background (UVB) intensity and dust-to-gas rati

Manami Sasaki, Wolfgang Pietsch, Frank Haberl

Based on XMM-Newton EPIC data of four pointings towards the Small Magellanic Cloud (SMC), results on timing and spectral analyses of 16 known high mass X-ray binaries (HMXBs) and HMXB candidates in the SMC are presented. We confirm the pulse periods of four sources which were known to show pulsations. In addition, two new X-ray pulsars are discovered: XMMU J

M. Monelli, L. Pulone, C. E. Corsi, M. Castellani

We present a new (V,B-V) Color-Magnitude Diagram (CMD) of the Carina dwarf spheroidal (dSph) that extends from the tip of the Red Giant Branch (RGB) down to about V=25 mag. Data were collected with the Wide Field Imager (WFI) available at 2.2m ESO/MPI telescope and cover an area of about 0.3 square degrees around the center of the galaxy. We confirm the occu

Marc Audard, Manuel Guedel, Stephen L. Skinner

We present the first spatially separated X-ray observation of the active UV Ceti binary with \textit{Chandra}, providing important new information on the relative X-ray activity levels of its nearly identical dM5.5e components. The two components had similar X-ray luminosities during low-level periods and emission measure loci derived from Low Energy Transmi

N. Bucciantini, J. M. Blondin, L. Del Zanna, E. Amato

Pulsars, formed during supernova explosions, are known to be sources of relativistic magnetized winds whose interaction with the expanding supernova remnants (SNRs) gives rise to a pulsar wind nebula (PWN). We present spherically symmetric relativistic magnetohydrodynamics (RMHD) simulations of the interaction of a pulsar wind with the surrounding SNR, both

Giuseppe Bono

We present recent results concerning distance determinations based on the two most popular primary distance indicators, namely classical Cepheids and RR Lyrae. We discuss the problems affecting the Cepheid distance scale, and in particular the dependence of fundamental Period-Luminosity (PL) and Period-Luminosity-Color (PLC) relations on the metal content. T

A. R. King, D. J. Rolfe, K. Schenker

We show that long-period dwarf novae offer a promising route for making Type Ia supernovae. For typical dwarf nova duty cycles d ~ 0.1 - 0.01, mass is accreted by the white dwarf mainly during dwarf nova outbursts at rates allowing steady nuclear burning of most of the accreted matter. Mass gains up to ~ 0.4 Msun are possible in this way. Although these are

Jesús Falcón-Barroso, Reynier F. Peletier, Alexandre Vazdekis, Marc Balcells

We present measurements of the near-infrared Calcium II triplet (CaT, CaT*), Paschen (PaT) and Magnesium (MgI) indices for a well-studied sample of 19 bulges of early to intermediate spiral galaxies. We find that both the CaT* and CaT indices decrease with central velocity dispersion (sigma) with small scatter. This dependence is similar to that recently fou

F. Durret, G. B. Lima Neto, W. Forman, E. Churazov

We have observed with XMM-Newton the extended 4 Mpc filament detected by the ROSAT PSPC in the neighbourhood of the cluster of galaxies Abell 85. We confirm that there is an extended feature, aligned at the same position angle as the major axis of the central cD, the bright cluster galaxies, and nearby groups and clusters. We find that the X-ray emission fro

Todd Adams, Eugene C. Loh, Segev BenZvi, Stefan Westerhoff

For our understanding of the origin of ultra high energy cosmic rays, the energy region between 10^17 and 10^19 eV is of crucial importance. Previous experiments have found indirect evidence that at these energies, the origin of cosmic rays changes from predominantly Galactic to extragalactic. In addition, weak evidence for an excess of cosmic rays from the

Nektarios Vlahakis, Arieh Konigl

We present exact radially self-similar solutions of special-relativistic magnetohydrodynamics representing ``hot&#39;&#39; super-Alfvenic outflows from strongly magnetized, rotating compact objects. We argue that such outflows can plausibly arise in gamma-ray burst (GRB) sources and demonstrate that, just as in the case of the trans-Alfvenic flows considered

Nektarios Vlahakis, Arieh Konigl

We present a general formulation of special-relativistic magnetohydrodynamics and derive exact radially self-similar solutions for axisymmetric outflows from strongly magnetized, rotating compact objects. We generalize previous work by including thermal effects and analyze in detail the various forces that guide, accelerate, and collimate the flow. We demons

Rachel S. Somerville, James S. Bullock, Mario Livio

Reducing the power on small scales relative to the `standard&#39; LCDM model alleviates a number of possible discrepancies with observations, and is favored by the recent analysis of WMAP plus galaxy and Lyman-alpha forest data. Here, we investigate the epoch of reionization in several models normalized to WMAP on large scales, and with sufficiently reduced

Barbara A. Whitney, Kenneth Wood, J. E. Bjorkman, Michael J. Wolff

We present 2-D radiation transfer models of Class I Protostars and show the effect of including more realistic geometries on the resulting spectral energy distributions and images. We begin with a rotationally flattened infalling envelope as our comparison model, and add a flared disk and bipolar cavity. The disk affects the spectral energy distribution most

J. R. Soto, J. J. Castro, E. Yépez, A. Calles

We present a density functional theory (DFT) calculation in the generalized gradient approximation to study the possibility for the existence of Jahn-Teller (JT) or pseudo Jahn-Teller (PJT) type local distortions in the La-Ba-Cu-O superconducting system. We performed the calculation and correspondingly group theory classification of the electronic ground sta

Richard L. White, Robert H. Becker, Xiaohui Fan, Michael A. Strauss

We present high signal-to-noise ratio Keck ESI spectra of the two quasars known to have Gunn-Peterson absorption troughs, SDSS J1030+0524 (z=6.28) and SDSS J1148+5251 (z=6.37). The Ly alpha and Ly beta troughs for SDSS J1030+0524 are very black and show no evidence for any emission over a redshift interval of ~0.2 starting at z=6. On the other hand, SDSS J11

G. German, A. de la Macorra

We construct a two-stage inflationary model which can accommodate early inflation at a scale $Λ_1$ as well as a second stage of inflation at $Λ_2$ with a single scalar field $ϕ$. We use a symmetric potential, valid in a frictionless world, in which the two inflationary periods have exactly the same scale, i.e. $Λ_1=Λ_2$. However, we see today $Λ_1 \gg Λ_2$ d

E. Il&#39;ichev, N. Oukhanski, A. Izmalkov, Th. Wagner

Under resonant irradiation, a quantum system can undergo coherent (Rabi) oscillations in time. We report evidence for such oscillations in a _continuously_ observed three-Josephson-junction flux qubit, coupled to a high-quality tank circuit tuned to the Rabi frequency. In addition to simplicity, this method of_Rabi spectroscopy_ enabled a long coherence time

L. F. Santos, M. I. Dykman

We show that, in a system with defects, two-particle states may experience destructive quantum interference, or antiresonance. It prevents an excitation localized on a defect from decaying even where the decay is allowed by energy conservation. The system studied is a qubit chain or an equivalent spin chain with an anisotropic ($XXZ$) exchange coupling in a

V. P. Goncalves, M. V. T. Machado

The double meson production in ultraperipheral heavy ions collisions is addressed, focusing on the particular case of rho-J/Psi from two-photon reactions. The cross section at photon level is obtained using distinct parameterizations for the gluon distribution on the light meson. The resulting estimates for the nuclear case are presented and discussed. As a

P. Facchi, D. A. Lidar, S. Pascazio

We unify the quantum Zeno effect (QZE) and the &#34;bang-bang&#34; (BB) decoupling method for suppressing decoherence in open quantum systems: in both cases strong coupling to an external system or apparatus induces a dynamical superselection rule that partitions the open system&#39;s Hilbert space into quantum Zeno subspaces. Our unification makes use of vo

E. V. Bezuglyi, V. S. Shumeiko, G. Wendin

We study non-equilibrium Josephson effect and phase-dependent conductance in three-terminal diffusive interferometers with short arms. We consider strong proximity effect and investigate an interplay of dissipative and Josephson currents co-existing within the same proximity region. In junctions with transparent interfaces, the suppression of the Josephson c

Antonio S. de Castro

The Dirac equation is solved for a pseudoscalar Coulomb potential in a two-dimensional world. An infinite sequence of bounded solutions are obtained. These results are in sharp contrast with those ones obtained in 3+1 dimensions where no bound-state solutions are found. Next the general two-dimensional problem for pseudoscalar power-law potentials is address

Kamal L. Panigrahi, Sanjay

We find classical solutions of D-branes in pp-wave spacetime with nonconstant NS-NS flux. We also present Dp-Dp&#39; bound state solutions in this background. We further analyze the supersymmetric properties of these brane solutions by solving the type IIB killing spinor equations explicitly.

Antonio Padilla

We derive the gravitational Hamiltonian starting from the Gauss-Bonnet action, keeping track of all surface terms. This is done using the language of orthonormal frames and forms to keep things as tidy as possible. The surface terms in the Hamiltonian give a remarkably simple expression for the total energy of a spacetime. This expression is consistent with

S. Boettcher

A new approach to exploring low-temperature excitations in finite-dimensional lattice spin glasses is proposed. By focusing on bond-diluted lattices just above the percolation threshold, large system sizes $L$ can be obtained which lead to enhanced scaling regimes and more accurate exponents. Furthermore, this method in principle remains practical for any di

Christian Bonatti, Boris Kolev

We prove that if f is an orientation-preserving homeomorphism of a closed orientable surface M whose singular set is totally disconnected, then f is topologically conjugate to a conformal transformation.

Krzysztof M. Graczyk, Jan T. Sobczyk

The algebraic solution of RPA equations nucleon re-interactions in the case of quasi elastic charged current neutrino - nucleus scattering is presented. Abelian algebra of matrices allows to extract four independent corrections to cross section separatly.Results of numerical computations are shown.

Patrick Valageas, Andrew J. Barber, Dipak Munshi

Weak gravitational lensing surveys are rapidly becoming important tools to probe directly the mass density fluctuations in the universe and its background dynamics. Earlier studies have shown that it is possible to model the statistics of the convergence field on small angular scales by suitably modeling the statistics of the underlying density field in the

Boris Kolev, Marie-Christine Peroueme

An orientation-preserving recurrent homeomorphism of the two-sphere which is not the identity is shown to admit exactly two fixed points. A recurrent homeomorphism of a compact surface with negative Euler characteristic is periodic.

Bruce Gendre, Didier Barret, Natalie A. Webb

We have discovered with XMM-Newton an X-ray source in the core of the globular cluster M13, whose X-ray spectral properties suggest that it is a quiescent neutron star X-ray binary. The spectrum can be well fitted with a pure hydrogen atmosphere model, with T=76 +/- 3 eV, R=12.8 +/- 0.4 km and an X-ray luminosity of 7.3 +/- 0.6 x 10^{32} erg/s. In the light

G. B. Crew, D. Q. Lamb, G. R. Ricker, J. -L. Atteia

A bright, x-ray-rich GRB was detected by HETE-2 at 11:18:34.03 UT on 11 Dec 2002. The WXM localization was to 14&#39; and relayed to the GCN 22 s after the start of the burst. The ground SXC localization was within 2&#39; of R.A. 08h 09m 00s, Dec 06d 44&#39; 20&#34; (J2000). GRB021211 consists of a single, FRED-like pulse with t90s of 2.3 s (85-400 keV) and

Toru Sasaki

We try to determine the partition function of ${\cal N}=4$ super Yang-Mills theoy for ADE gauge group on K3 by self-dualizing our previous ADE partition function. The resulting partition function satisfies gap condition.

L. -A. Wu, D. A. Lidar

Inherent gate errors can arise in quantum computation when the actual system Hamiltonian or Hilbert space deviates from the desired one. Two important examples we address are spin-coupled quantum dots in the presence of spin-orbit perturbations to the Heisenberg exchange interaction, and off-resonant transitions of a qubit embedded in a multilevel Hilbert sp

Jonathan L. DuBois, Henry R. Glyde

We investigate the properties of hard core Bosons in harmonic traps over a wide range of densities. Bose-Einstein condensation is formulated using the one-body Density Matrix (OBDM) which is equally valid at low and high densities. The OBDM is calculated using diffusion Monte Carlo methods and it is diagonalized to obtain the &#34;natural&#34; single particl

Gergely Szirmai, Peter Szepfalusy, Krisztian Kis-Szabo

Finite temperature Green&#39;s function technique is used to calculate the energies and damping rates of elementary excitations of the homogeneous, dilute, spin-1 Bose gases below the Bose-Einstein condensation temperature both in the density and spin channels. For this purpose the self-consistent dynamical Hartree-Fock model is formulated, which takes into

S. A. Paston, E. V. Prokhvatilov, V. A. Franke

Gauge invariant regularization of quantum field theory in the framework of Light-Front (LF) Hamiltonian formalism via introducing a lattice in transverse coordinates and imposing boundary conditions in LF coordinate $x^-$ for gauge fields on the interval $|x^-|\le L$ is considered. The remaining ultraviolet divergences in the longitudinal momentum $p_-$ are

M. Adak, T. Dereli, L. H. Ryder

The contribution of gravitational neutrino oscillations to the solar neutrino problem is studied by constructing the Dirac Hamiltonian and calculating the corresponding dynamical phase in the vicinity of the Sun in a non-Riemann background Kerr space-time with torsion and non-metricity. We show that certain components of non-metricity and the axial as well a

V. K. Dobrev

The present paper contains two interrelated developments. First, are proposed new generalized Verma modules. They are called k-Verma modules, k\in N, and coincide with the usual Verma modules for k=1. As a vector space a k-Verma module is isomorphic to the symmetric tensor product of k copies of the universal enveloping algebra U(g^-), where g^- is the subal

I. M. Khalatnikov, A. Yu. Kamenshchik

This paper is withdrawn by the authors

I. S. Elfimov, T. Saha-Dasgupta, M. A. Korotin

The common interpretation of the LDA band structure of V$_{2}$O$_{3}$ is that the apparent splitting of the $a_{1g}$ band into a low intensity structure deep below the Fermi energy and a high intensity feature above it, is due to the bonding-antibonding coupling of the vertical V-V pair. Using tight-binding fitting to --as well as first-principles NMTO downf

Yuval Grossman, Zoltan Ligeti, Yosef Nir, Helen Quinn

We consider CP asymmetries in neutral $B$ meson decays to $η&#39; K_S$, $ϕK_S$, and $K^+ K^- K_S$. We use SU(3) relations to estimate or bound the contributions to these amplitudes proportional to $V_{ub}^*V_{us}$. Such contributions induce a deviation of the $S_f$ terms measured in these time dependent CP asymmetries from that measured for $ψK_S$. For the $

M. Sasaki, O. C. Martin

We use simulations within the Migdal-Kadanoff real space renormalization approach to probe the scales relevant for rejuvenation and memory in spin glasses. One of the central questions concerns the role of temperature chaos. First we investigate scaling laws of equilibrium temperature chaos, finding super-exponential decay of correlations but no chaos for th

Argelia Bernal, Tonatiuh Matos, Dario Nunez

The scalar field endowed with a cosh scalar field potential, behaves exactly in the same way as cold dark matter (CDM) in the region where the scalar field oscillates around its minimum. Also, in the linear regime, the scalar field dark matter (SFDM) hypothesis predicts the same structure formation as the cold dark matter one. This means that CDM and SFDM ar

T. Hirayama, B. Holdom

The search for regular black hole solutions in classical gravity leads us to consider a core of Euclidean signature in the interior of a black hole. Solutions of Lorentzian and Euclidean general relativity match in such a way that energy densities and pressures of an isotropic perfect fluid form are everywhere finite and continuous. Although the weak energy

S. Q. Wu, M. L. Yan

The Newman-Penrose formalism is used to derive the Teukolsky master equations controlling massless scalar, neutrino, electromagnetic, gravitino, and gravitational field perturbations of the Kerr-de Sitter spacetime. Then the quantum entropy of a non-extreme Kerr-de Sitter black hole due to arbitrary spin fields is calculated by the improved thin-layer brick

Alison Farmer, Eric Agol

We make predictions for the rate of discovery of eclipsing white dwarf-main sequence (WD-MS) binaries in terrestrial-planet transit searches, taking the planned Kepler and Eddington missions as examples. We use a population synthesis model to characterize the Galactic WD-MS population, and we find that, despite increased noise due to stellar variability comp

M. Kirchbach

I make the case that the nucleon excitations do not exist as isolated higher spin states but are fully absorbed by (K/2,K/2)*[(1/2,0)+ (0,1/2)] multiplets taking their origin from the rotational and vibrational excitations of an underlying quark--diquark string. The Δ(1232) spectrum presents itself as the exact replica (up to Δ(1600)) of the nucleon spectrum

David A. Lowe, Horatiu Nastase, Sanjaye Ramgoolam

We propose a Matrix Theory approach to Romans&#39; massive Type IIA supergravity. It is obtained by applying the procedure of Matrix Theory compactifications to Hull&#39;s proposal of the Massive Type IIA String Theory as M-Theory on a twisted torus. The resulting Matrix Theory is a super-Yang Mills theory on large N three-branes with a space dependent non-c

Michael D. Hartl

We discuss several numerical methods for calculating Lyapunov exponents (a quantitative measure of chaos) in systems of ordinary differential equations. We pay particular attention to constrained systems, and we introduce a variety of techniques to address the complications introduced by constraints. For all cases considered, we develop both deviation vector

Ian G. McCarthy, Gilbert P. Holder, Arif Babul, Michael L. Balogh

Studies of cluster X-ray scaling relations have led to suggestions that non-gravitational processes, e.g., radiative cooling and/or &#34;preheating&#34;, have significantly modified the entropy of the intracluster medium (ICM). For the first time, we test this hypothesis through a comparison of predicted thermal Sunyaev-Zeldovich (SZ) effect scaling relation

Mark Heiligman

Quantum algorithms for several problems in graph theory are considered. Classical algorithms for finding the lowest weight path between two points in a graph and for finding a minimal weight spanning tree involve searching over some space. Modification of classical algorithms due to Dijkstra and Prim allows quantum search to replace classical search and lead

Hide Akisato

We show that a superconducting circuit containing two loops, when treated with Macroscopic Quantum Coherence (MQC) theory, constitutes a complete two-bit quantum computer. The manipulation of the system is easily implemented with alternating magnetic fields. A \textit{universal} set of quantum gates is deemed available by means of all unitary single bit oper

Yuri I. Ozhigov

Limitation of computational resources is considered as a universal principle that for simulation is as fundamental as physical laws are. It claims that all experimentally verifiable implications of physical laws can be simulated by the effective classical algorithms. It is demonstrated through a completely deterministic approach proposed for the simulation o

F. A. Bovino, P. Varisco, A. M. Colla, G. Castagnoli

We report on theoretical and experimental demonstration of high-efficiency coupling of two-photon entangled states produced in the nonlinear process of spontaneous parametric down conversion into a single-mode fiber. We determine constraints for the optimal coupling parameters. This result is crucial for practical implementation of quantum key distribution p

Cyriaque Genet, Astrid Lambrecht, Paulo Maia Neto, Serge Reynaud

The Casimir force between two metallic plates is affected by their roughness state. This effect is usually calculated through the so-called `proximity force approximation&#39; which is only valid for small enough wavevectors in the spectrum of the roughness profile. We introduce here a more general description with a wavevector-dependent roughness sensitivit

Z. Idziaszek, L. Santos, M. Baranov, M. Lewenstein

The collective Raman cooling of trapped one- and two-component Fermi gases is considered. We obtain the quantum master equation that describes the laser cooling in the festina lente regime, for which the heating due to photon reabsorption can be neglected. For the two-component case the collisional processes are described within the formalism of quantum Bolt

L. H. Ford

The possible normal modes of vibration of a nearly spherical virus particle are discussed. Two simple models for the particle are treated, a liquid drop model and an elastic sphere model. Some estimates for the lowest vibrational frequency are given for each model. It is concluded that this frequency is likely to be of the order of a few GHz for particles wi

Lei Liu, C. S. Jayanthi, Shi-Yu Wu

A flexible scheme for decomposing the vibrational density of states in terms of pair vibrational density of states is presented. This scheme provides the linkage between the site vibrational density of states and pair vibrational density of states so that vibrational modes, in particular localized modes, can be conveniently examined in terms of the correlati

Andrej Vilfan, Thomas Duke

We investigate the isometric transient response of muscle using a quantitative stochastic model of the actomyosin cycle based on the swinging lever-arm hypothesis. We first consider a single pair of filaments, and show that when values of parameters such as the lever-arm displacement and the crossbridge elasticity are chosen to provide effective energy trans

E. R. Tracy, A. N. Kaufman

For a multicomponent wave field propagating into a multidimensional conversion region, the rays are shown to be helical, in general. For a ray-based quantity to have a fundamental physical meaning it must be invariant under two groups of transformations: congruence transformations (which shuffle components of the multi-component wave field) and canonical tra

M. A. Manna, A. Neveu

From a columnar approximation of the Euler equations of an incompressible fluid with surface tension, we derive in the short-wave approximation a new integrable classical 1+1 dimensional field theory for the motion of the surface. Together with a Lorentz invariance,this system has the novel feature of solutions which become multiple valued in finite time.

F. Gomez, A. Iglesias, R. Lobato, J. Mosquera

We have constructed and tested a 2d position sensitive parallel-plate gas ionization chamber with scanned charge transfer readout. The scan readout method described here is based on the development of a new position dependent charge transfer technique. It has been implemented by using gate strips perpendicularly oriented to the collector strips. This solutio

P. Di Trapani, G. Valiulis, A. Piskarskas, O. Jedrkiewicz

We observe the formation of an intense optical wavepacket fully localized in all dimensions, i.e. both longitudinally (in time) and in the transverse plane, with an extension of a few tens of fsec and microns, respectively. Our measurements show that the self-trapped wave is a X-shaped light bullet spontaneously generated from a standard laser wavepacket via

V. F. Tamari

The field of an electromagnetic (E) dipole has been examined using general relativistic (R) and quantum mechanical (Q) points of view, and an E=Q=R equivalence principle presented whereas the curvature of the electromagnetic streamlines of the field are taken to be evidence of the distortion of spacetime, and hence of the presence of a gravitational field su

Vladislav E. Chernov, Boris A. Zon

An explicit analytic description is given for dipole-bound anion (DBA) as an excess electron bound to the molecular neutral due to its dipole moment. The calculated DBA photodetachment cross-section displays $\proptoω^{-2}$ behavior for large $ω$, in complete accordance with the experimental data [Bailey \textit{et al.}, J. Chem. Phys \textbf{104}, 6976 (199

V. Kumarappan, M. Krishnamurthy, D. Mathur

Energetic, highly-charged oxygen ions, $O^{q+}$ ($q\leq 6$), are copiously produced upon laser field-induced disassembly of highly-charged water clusters, $(H_2O)_n$ and $(D_2O)_n$, $n\sim$ 60, that are formed by seeding high-pressure helium or argon with water vapor. $Ar_n$ clusters (n$\sim$40000) formed under similar experimental conditions are found under

M. Krishnamurthy, D. Mathur, V. Kumarappan

The disassembly of molecular clusters $(N_2)_n$ ($n$=50-3000) in strong optical fields is investigated using two-dimensional time-of-flight spectrometry. Very highly charged ions are formed with a two-component energy distribution. A low-energy, isotropic component correlates with Coulomb explosion. A high-energy, anisotropic component, that results from a `

Mario Rabinowitz

Although he was the recipient of a Nobel Prize and despite the greatness of his accomplishments, Julian Schwinger is almost an unsung hero of our age . He is relatively unknown to the general population, even though in the physics community he was a renowned theoretician and teacher of physics. He shared the 1965 Nobel Prize in physics with Richard P. Feynma

A. Capella, D. Sousa

New data on the $J/ψ$ suppression both in proton-nucleus and in lead-lead interactions have been presented recently by the NA50 collaboration. We show that these data, together with the final ones on sulfur-uranium interactions, can be described in the framework of the comovers interaction model with a unique set of three parameters : the nuclear absorption

P. Sarriguren, E. Moya de Guerra, L. Pacearescu, Amand Faessler

We study Gamow-Teller strength distributions of 76Ge and 76Se within a deformed QRPA formalism, which includes residual spin-isospin forces in the particle-hole and particle-particle channels. We consider two different methods to construct the quasiparticle basis, a selfconsistent approach based on a deformed Hartree-Fock calculation with density-dependent S

J. -M. Laget

Twenty years after P. Sauer released the state of the art Faddeev solution of the bound state three nucleon systems, I revisit photo and electrodisengration of few body systems with a special emphasis on the prospects opened at Jefferson Laboratory.

Vincent Regnard

Ce papier presente la notion de signal de transition de phase pour un systeme de taille finie. Il se concentre sur le role des contraintes physiques sur ces signaux et la robustesse quant au changement d&#39;ensemble statistique. Des resultats obtenus avec un modele de gaz sur reseau sont presentes en analogie avec les observations effectuees en collisions d

T. Sato, D. Uno, T. -S. H. Lee

The dynamical model of pion electroproduction has been extended to investigate the weak pion production reactions. The predicted cross sections of neutrino-induced pion production reactions are in good agreement with the existing data. We show that the renormalized(dressed) axial N-$Δ$ form factor contains large dynamical pion cloud effects and this renormal