May 2002 arXiv papers — page 15

H. C. Huang

Recent results of rare B decay analyses based on 31.9 million $B\bar{B}$ collected with the Belle detector at the KEKB asymmetric $e^+e^-$ collider are presented. We have made the first observation of charmless baryonic decay $B^\pm \to p \bar{p} K^\pm$, the three-body $B^0 \to K^0 π^+ π^-$ and $B^0 \to K^0 K^+ K^-$. The measured branching fractions are $\ma

V. Ammosov, V. Gapienko, A. Ivanilov, A. Semak

Timing characteristics of two multigap RPCs were compared. One had four subgaps 0.3 mm wide and the other - two subgaps 0.6 mm wide. Specially developed electronics was used. Electronics resolution convoluted with measured charge spectra at operating point was estimated as about 65 ps. The best time resolutions obtained at low counting rate were 75 ps for th

K. Rabbertz

From 1996 up to 2000 the LEP collider at CERN has operated at center of mass energies above the production threshold for W boson pairs of approximately 160 GeV. The obtained data are used to extract a preliminary W mass value of (80.450 +- 0.039) GeV by direct reconstruction. To a large extent the uncertainty is due to systematic effects especially in the fu

Alberto A. Garcia, Cuauhtemoc Campuzano

It is shown that within conformally flat stationary axisymmetric spacetimes, besides of the static family, there exists a new class of metrics, which is always stationary and axisymmetric. All these spacetimes, the static and the stationary ones, are endowed with an arbitrary function depending on the two non--Killingian coordinates. The explicit form of thi

George E. A. Matsas, Daniel A. T. Vanzella

We discuss the decay of accelerated protons and illustrate how the Fulling-Davies-Unruh effect is indeed mandatory to maintain the consistency of standard Quantum Field Theory. The confidence level of the Fulling-Davies-Unruh effect must be the same as that of Quantum Field Theory itself.

S. Biswas, P. Misra, I. Chowdhury

In this paper we investigate the phenomenon of particle production of massles scalar field, in a model of spacetime where the chronology horizon could be formrd, using the method of complex time WKB approximation (CWKB). For the purpose, we take two examples in a model of spacetime, one already discussed by Sushkov, to show that the mode of particle producti

S. Biswas, P. Misra, I. Chowdhury

In this work we study the particle production in time dependent periodic potential using the method of complex time WKB (CWKB) approximation. In the inflationary cosmology at the end of inflationary stage, the potential becomes time dependent as well as periodic. Reheating occurs due to particle production by the oscillating inflaton field. Using CWKB we obt

Lars Andersson

In this report, which is an extended version of that appearing in the Proceedings of GR16, I will give a summary of the main topics covered in Session A.3. on mathematical relativity at GR16, Durban. The summary is mainly based on extended abstracts submitted by the speakers. I would like to thank all participants for their contributions and help with this s

Qin Zhang, John Danskin, Neal Young

Pattern-matching-based document-compression systems (e.g. for faxing) rely on finding a small set of patterns that can be used to represent all of the ink in the document. Finding an optimal set of patterns is NP-hard; previous compression schemes have resorted to heuristics. This paper describes an extension of the cross-entropy approach, used previously fo

Edward Loper, Steven Bird

NLTK, the Natural Language Toolkit, is a suite of open source program modules, tutorials and problem sets, providing ready-to-use computational linguistics courseware. NLTK covers symbolic and statistical natural language processing, and is interfaced to annotated corpora. Students augment and replace existing components, learn structured programming by exam

Chung-chieh Shan

I propose a variable-free treatment of dynamic semantics. By "dynamic semantics" I mean analyses of donkey sentences ("Every farmer who owns a donkey beats it") and other binding and anaphora phenomena in natural language where meanings of constituents are updates to information states, for instance as proposed by Groenendijk and Stokhof. By

Chung-chieh Shan

Accounts of semantic phenomena often involve extending types of meanings and revising composition rules at the same time. The concept of monads allows many such accounts -- for intensionality, variable binding, quantification and focus -- to be stated uniformly and compositionally.

A. D. Gromko, Y. -D. Chuang, A. V. Fedorov, Y. Aiura

A well-known peak-dip-hump structure exists near $(π, 0)$ in superconducting state ARPES spectra of $Bi_{2}Sr_{2}CaCu_{2}O_{8+δ}$ (Bi2212). Here we report results on optimal and overdoped Bi2212 samples indicating the traditional peak-dip-hump structure observed near $(π,0)$ is largely due to bilayer splitting. However a separate, much weaker peak-dip hump (

D. J. Watts, P. S. Dodds, M. E. J. Newman

Social networks have the surprising property of being "searchable": Ordinary people are capable of directing messages through their network of acquaintances to reach a specific but distant target person in only a few steps. We present a model that offers an explanation of social network searchability in terms of recognizable personal identities: sets

A. J. Rimberg, W. Lu

We have developed a novel system consisting of a superconducting single-electron transistor (S-SET) coupled to a two-dimensional electron gas (2DEG), for which the dissipation can be tuned in the immediate vicinity of the S-SET. To analyze our results, we have developed a model of the environment for S-SET/2DEG systems that includes electromagnetic fluctuati

Sergei Maslov, Kim Sneppen

Molecular networks guide the biochemistry of a living cell on multiple levels: its metabolic and signalling pathways are shaped by the network of interacting proteins, whose production, in turn, is controlled by the genetic regulatory network. To address topological properties of these two networks we quantify correlations between connectivities of interacti

L. Khaykovich, F. Schreck, G. Ferrari, T. Bourdel

We report the production of matter-wave solitons in an ultracold lithium 7 gas. The effective interaction between atoms in a Bose-Einstein condensate is tuned with a Feshbach resonance from repulsive to attractive before release in a one-dimensional optical waveguide. Propagation of the soliton without dispersion over a macroscopic distance of 1.1 mm is obse

Bernd A. Berg, Alain Billoire, Wolfhard Janke

We study the Parisi overlap probability density P_L(q) for the three-dimensional Ising ferromagnet by means of Monte Carlo (MC) simulations. At the critical point P_L(q) is peaked around q=0 in contrast with the double peaked magnetic probability density. We give particular attention to the tails of the overlap distribution at the critical point, which we co

G. Cuniberti, G. Fagas, K. Richter

The influence of contacts on linear transport through a molecular wire attached to mesoscopic tubule leads is studied. It is shown that low dimensional leads, such as carbon nanotubes, in contrast to bulky electrodes, strongly affect transport properties. By focusing on the specificity of the lead-wire contact, we show, in a fully analytical treatment, that

I. Varga

The distribution of the correlation dimension in a power law band random matrix model having critical, i.e. multifractal, eigenstates is numerically investigated. It is shown that their probability distribution function has a fixed point as the system size is varied exactly at a value obtained from the scaling properties of the typical value of the inverse p

L. E. Golub, S. Pedersen

We present calculations of the spin and phase relaxation rates in GaAs/AlGaAs $p$-type quantum wells. These rates are used to derive the temperature dependence of the weak-localization correction to the conductivity. In $p$-type quantum wells both weak localization and weak anti-localization are present due to the strong spin-orbit interaction. When determin

I. Avgin, D. L. Huber

we investigate the thermodynamic properties of weakly anisotropic disordered magnetic chains where the nearest-neighbor Heisenberg exchange coupling is the dominant spin-spin interaction. In addition to the exchange interaction, there is single-ion anisotropy with the direction of the easy axis being the same for all spins. The analysis is carried out in the

A. Micheli, D. Jaksch, J. I. Cirac, P. Zoller

We investigate schemes to dynamically create many particle entangled states of a two component Bose-Einstein condensate in a very short time proportional to 1/N where $N$ is the number of condensate particles. For small $N$ we compare exact numerical calculations with analytical semiclassical estimates and find very good agreement for $N \geq 50$. We also es

David Djajaputra, Bernard R. Cooper

We have examined a method of direct extraction of accurate tight-binding parameters from an ab-initio band-structure calculation. The linear muffin-tin potential method, in its full-potential implementation, has been used to provide the hamiltonian and overlap matrix elements in the momentum space. These matrix elements are Fourier transformed to real space

G. Cuniberti, L. Craco, D. Porath, C. Dekker

We propose a model Hamiltonian for describing charge transport through short homogeneous double stranded DNA molecules. We show that the hybridization of the overlapping pi orbitals in the base-pair stack coupled to the backbone is sufficient to predict the existence of a gap in the nonequilibrium current-voltage characteristics with a minimal number of para

James F. Lutsko, J. W. Dufty

The presence of long-ranged correlations in a fluid undergoing uniform shear flow is investigated. An exact relation between the density autocorrelation function and the density-mometum correlation function implies that the former must decay more rapidly than $1/r$, in contrast to predictions of simple mode coupling theory. Analytic and numerical evaluation

A. D. Drozdov, J. deC. Christiansen

A model is derived for the viscoelastic response of glasses at isothermal uniaxial deformation with small strains. A glass is treated as an ensemble of relaxing units with various activation energies for rearrangement. With reference to the energy-landscape concept, the rearrangement process is thought of as a series of hops of relaxing units (trapped in the

Emily Chattopadhyay, Indrani Bose

A spin-1/2 antiferromagnetic(AFM) generalised ladder model is constructed which consists of four-spin plaquettes, coupled through weaker exchange interactions, to two-spin rungs. In an extended parameter regime, the exact ground state of the ladder is determined. In this state, the four-spin plaquettes and the rungs are in their ground state spin configurati

I. V. Ponomarev, A. E. Meyerovich

The effect of random surface roughness on hydrodynamics of viscous incompressible liquid is discussed. Roughness-driven contributions to hydrodynamic flows, energy dissipation, and friction force are calculated in a wide range of parameters. When the hydrodynamic decay length (the viscous wave penetration depth) is larger than the size of random surface inho

A. D. Drozdov, J. deC. Christiansen

Four series of tensile loading-unloading tests are performed on isotactic polypropylene in the sub-yield domain of deformations at room temperature. In the first series, injection-molded specimens are used as produced, whereas in the other series the samples are annealed for 24 h at 120, 140 and 160 C, which covers the low-temperature region and an initial p

C. P. Search, S. Poetting, W. Zhang, P. Meystre

We generalize the quantum optical input-output theory developed for optical cavities to ultracold fermionic atoms confined in a trapping potential, which forms an "atom cavity". In order to account for the Pauli exclusion principle, quantum Langevin equations for all cavity modes are derived. The dissipative part of these multi-mode Langevin equation

Harald Willenberg, Gottfried H. Dohler, Jerome Faist

The link between the inversion gain of quantum cascade structures and the Bloch gain in periodic superlattices is presented. The proposed theoretical model based on the density matrix formalism is able to treat the gain mechanism of the Bloch oscillator and Quantum cascade laser on the same footing by taking into account in-plane momentum relaxation. The mod

Helmut G. Katzgraber, A. P. Young

We present results of Monte Carlo simulations, using parallel tempering, on the three- and four-dimensional Edwards-Anderson Ising spin glass with Gaussian couplings at low temperatures with free boundary conditions. Our results suggest that large-scale low-energy excitations may be space filling. The data implies that the energy of these excitations increas

Helmut G. Katzgraber, A. P. Young

We report results for simulations of the four-dimensional XY spin glass using the parallel tempering Monte Carlo method at low temperatures for moderate sizes. Our results are qualitatively consistent with earlier work on the three-dimensional gauge glass as well as three- and four-dimensional Edwards-Anderson Ising spin glass. An extrapolation of our result

J. S. Sá Martins, J. B. Rundle, M. Anghel, W. Klein

A precursory dynamics, motivated by the analysis of recent experiments on solid-on-solid friction, is introduced in a continuous cellular automaton that mimics the essential physical contents of earthquake source processes. The resulting system of equations for the inter-event cycle can be decoupled and yields an analytical solution in the mean-field limit,

G. E. Romero, S. A. Cellone, J. A. Combi, I. Andruchow

We present results of a photometric CCD study of the incidence of microvariability in the optical emission of a sample of 20 blazars detected at gamma-ray energies by the EGRET instrument of the Compton Gamma-Ray Observatory. We have observed strong outbursts in some sources, but many others displayed no significant variability on timescales of hours. The ty

S. I. Ipatov

The orbital evolution of asteroids from the 3:1 and 5:2 resonances with Jupiter under the gravitational influence of planets was investigated both by the Bulirsh-Stoer method and by a symplectic method. The probabilities of collisions of asteroids with the terrestrial planets were calculated for orbital elements obtained with a step of 500 yr. The ratio of a

S. I. Ipatov

We suppose that some large trans-Neptunian objects could be formed directly by the compression of rarefied dust condensations of the protoplanetary disk, but not by the accretion of smaller planetesimals. About 0.0015 of former Jupiter-crossing objects can get orbits with aphelia inside Jupiter's orbit (mainly less than 4.7 AU) during more than 1 Myr. A

Asantha Cooray

We discuss a possibility to directly reconstruct the CMB polarization field at the last scattering surface by accounting for modifications imposed by the gravitational lensing effect. The suggested method requires a tracer field of the large scale structure lensing potentials that deflected propagating CMB photons from the last scattering surface. This requi

Dusan Turcan, Shantanu Desai

Using the Super-Kamiokande neutrino observatory, a search was conducted for neutrinos produced in coincidence with gamma-ray bursts observed by the BATSE detector. Super-Kamiokande data in the neutrino energy range of 7 MeV ~ 100 TeV were analyzed. For gamma-ray bursts that occurred between 1996 April and 2000 May, no statistically significant signal in exce

S. C. Gallagher, W. N. Brandt, G. Chartas, R. M. Sambruna

We are in the process of obtaining a complete sample of exploratory X-ray observations of broad absorption line (BAL) QSOs from the Large Bright Quasar Survey (LBQS). This survey is composed of short (5-7 ks) Chandra ACIS-S3 observations designed to significantly constrain X-ray fluxes and hardness ratios. Our sample avoids the selection biases of some previ

Jaime Alvarez-Muñiz, Ralph Engel, T. K. Gaisser, Jeferson A. Ortiz

We present a fast one dimensional hybrid method to efficiently simulate extensive air showers up to the highest observed energies. Based on precalculated pion showers and a bootstrap technique, our method predicts the average shower profile, the number of muons at detector level above several energy thresholds as well as the fluctuations of the electromagnet

M. J. Richter, D. T. Jaffe, Geoffrey A. Blake, J. H. Lacy

We report on a limited search for pure-rotational molecular hydrogen emission associated with young, pre-main-sequence stars. We looked for H_2 v=0 J = 3->1 and J = 4->2 emission in the mid-infrared using the Texas Echelon-Cross-Echelle Spectrograph (TEXES) at NASA's 3m Infrared Telescope Facility. The high spectral and spatial resolution of our observat

Donald M. Terndrup, Marc Pinsonneault, Robin D. Jeffries, Alison Ford

We report new measures of radial velocities and rotation rates (v sin i) for 51 F and early-G stars in the open cluster NGC2516, and combine these with previously published data. From high signal-to-noise spectra of two stars, we show that NGC2516 has a relative iron abundance with respect to the Pleiades of delta([Fe/H])= +0.04 +/- 0.07 at the canonical red

Valentina D'Odorico, Patrick Petitjean, Stefano Cristiani

We study the transverse clustering properties of high matter density peaks as traced by high column density absorption systems (either Lyman limit systems characterized by N(HI)> 2 x 10^{17} cm^{-2} or CIV systems with W_{r}> 0.5 A) at redshifts between 2 and 3 with UVES spectra of two QSO pairs (UM680/UM681 at 56 arcsec angular separation and Q2344+1228/Q23

S. B. Popov, M. E. Prokhorov

In this paper we review present state of theoretical and observational exploration of isolated neutron stars. We mainly discuss objects which do not show usual radiopulsar activity. We include into our review the following types of objects: dim X-ray sources in the Galactic disk and in globular clusters; compact X-ray sources in supernova remnants; anomalous

C. O. Wright, T. G. Brainerd

We investigate the occurrence of multiple weak deflections in deep data sets which are used to detect galaxy-galaxy lensing. Using the galaxies in the HDF (North) for which both redshifts and rest-frame blue luminosities are known, we show that the probability for a given source galaxy to be lensed by two or more foreground galaxies exceeds 50% for z_s > 1,

N. Peixinho, A. Doressoundiram, J. Romon-Martin

We report on observations of two bright Trans-Neptunian Objects (TNOs) - 1999 TC36 and 1998 SN165}- during two observational campaigns, as part of the Meudon Multicolor Survey of Outer Solar System Objects. V-J color was measured for 1999 TC36 (V-J=2.34+/-0.18), which combined with previous measured colors in the visible, indicate a red reflectivity spectrum

S. D. Doty, E. F. van Dishoeck, F. F. S. van der Tak, A. M. S. Boonman

We present detailed thermal and gas-phase chemical models for the envelope of the massive star-forming region AFGL 2591. Time- and space-dependent chemistry are used to study the physical structure proposed by van der Tak et al. (1999; 2000), and the chemical evolution of this region. The model is compared with observations for 29 species covering a wide ran

I. Trujillo, J. A. L. Aguerri, C. M. Gutierrez, N. Caon

Using photometric and redshift data for the Virgo and Coma clusters, we present evidence for a correlation between the light concentration of elliptical galaxies (including dwarf ellipticals) and the local 3-D (i.e. non-projected) density of the clusters: more concentrated ellipticals are located in denser regions. The null hypothesis (i.e. the absence of an

L. Del Zanna, N. Bucciantini

Multidimensional shock-capturing numerical schemes for special relativistic hydrodynamics (RHD) are computationally more expensive than their correspondent Euler versions, due to the nonlinear relations between conservative and primitive variables and to the consequent complexity of the Jacobian matrices (needed for the spectral decomposition in most of the

I. Soszynski, K. Zebrun, A. Udalski, P. R. Wozniak

We present a Catalog of high proper motion (HPM) stars detected in the foreground of central parts of the Magellanic Clouds. The Catalog contains 2161 objects in the 4.5 square degree area towards the LMC, and 892 HPM stars in the 2.4 square degree area towards the SMC. The Catalog is based on observations collected during four years of the OGLE-II microlens

U. Munari, A. Henden, S. Kiyota, D. Laney

V838 Mon is marking one of the most mysterious stellar outbursts on record. The spectral energy distribution of the progenitor resembles an under-luminous F main sequence star (at V=15.6 mag), that erupted into a cool supergiant following a complex and multi-maxima lightcurve (peaking at V=6.7 mag). The outburst spectrum show BaII, LiI and lines of several s

Jungyeon Cho, A. Lazarian, Ethan Vishniac

Turbulence is the most common state of astrophysical flows. In typical astrophysical fluids, turbulence is accompanied by strong magnetic fields, which has a large impact on the dynamics of the turbulent cascade. Recently, there has been a significant breakthrough on the theory of magnetohydrodynamic (MHD) turbulence. For the first time we have a scaling mod

Jungyeon Cho, A. Lazarian

Measurements of intensity and polarization of diffuse Galactic synchrotron emission as well as starlight polarization reveal power law spectra of fluctuations. We show that these fluctuations can arise from magnetohydrodynamic (MHD) turbulence in the Galactic disk and halo. To do so we take into account the converging geometry of lines of sight for the obser

A. Lazarian, Huirong Yan

We discuss the relative grain motions due to MHD turbulence in interstellar medium. It has been known for decades that turbulent drag is an efficient way to induce grain relative motions. However, earlier treatments disregarded magnetic field and used Kolmogorov turbulence. Unlike hydro turbulence, MHD turbulence is anisotropic on small scales. Moreover, com

Jungyeon Cho, A. Lazarian

We present a model for compressible sub-Alfvenic isothermal magnetohydrodynamic (MHD) turbulence in low-beta plasmas and numerically test it. We separate MHD fluctuations into 3 distinct families - Alfven, slow, and fast modes. We find that, production of slow and fast modes by Alfvenic turbulence is suppressed. As a result, Alfven modes in compressible regi

Frederic Zagury

The standard interpretation of the extinction curve does not agree with some observations. The light we receive from a reddened star must be contaminated by starlight scattered at very small angular distances from the star. The true extinction curve is a straight line from the near infrared to the far-UV. If so, all interstellar dust models must be questionn

L. V. E. Koopmans, T. Treu

We have measured the kinematic profile of the early-type (E/S0) lens galaxy in the system 0047-281 (z=0.485) with the {\sl Echelle Spectrograph and Imager} (ESI) on the W.M. Keck--II Telescope, as part of the {\sl Lenses Structure and Dynamics (LSD) Survey}. The central velocity dispersion is σ=229\pm 15 \kms, and the dispersion profile is nearly flat to bey

F. Baldovin, A. Robledo

Using the Feigenbaum renormalization group (RG) transformation we work out exactly the dynamics and the sensitivity to initial conditions for unimodal maps of nonlinearity $ζ>1$ at both their pitchfork and tangent bifurcations. These functions have the form of $q$-exponentials as proposed in Tsallis' generalization of statistical mechanics. We determine

KLOE collaboration

Since april 1999, the KLOE experiment at DAFNE has collected about 200 inverse pb of data, produced in electron-positron collision at the c.m. energy of 1020 MeV, the mass of the phi meson. These data have been used for detailed studies on the phi radiative decays, as well as on rare K short decays. The first results, based on the 20 inverse pb collected in

Marcelo A. Montemurro, Francisco A. Tamarit, Celia Anteneodo

We analyze numerically the out-of-equilibrium relaxation dynamics of a long-range Hamiltonian system of $N$ fully coupled rotators. For a particular family of initial conditions, this system is known to enter a particular regime in which the dynamic behavior does not agree with thermodynamic predictions. Moreover, there is evidence that in the thermodynamic

N. J. Curro, P. G. Pagliuso, J. L. Sarrao, J. D. Thompson

We measure the spin lattice relaxation of the In(1) nuclei in the CeMIn_5 materials, extract quantitative information about the low energy spin dynamics of the lattice of Ce moments in both CeRhIn_5 and CeCoIn_5, and identify a crossover in the normal state. Above a temperature T* the Ce lattice exhibits "Kondo gas" behavior characterized by local fl

G. Wilpers, T. Binnewies, C. Degenhardt, U. Sterr

We demonstrate how to realize an optical clock with neutral atoms that is competitive to the currently best single ion optical clocks in accuracy and superior in stability. Using ultracold atoms in a Ca optical frequency standard we show how to reduce the relative uncertainty to below 1E-15. We observed atom interferences for stabilization of the laser to th

Evan Scannapieco, Rennan Barkana

We develop an analytical formalism that is suitable for studying inhomogeneous structure formation, by studying the joint statistics of dark matter halos forming at two points. Extending the Bond et al. (1991) derivation of the mass function of virialized halos, based on excursion sets, we derive an approximate analytical expression for the ``bivariate'&

E. I. Chiang

The dynamical evolution of Classical Kuiper Belt Objects (CKBOs) divides into two parts, according to the secular theory of test particle orbits. The first part is a forced oscillation driven by the planets, while the second part is a free oscillation whose amplitude is determined by the initial orbit of the test particle. We extract the free orbital inclina

Arjan Keurentjes, Savdeep Sethi

We consider the tensor theory on coincident E8 5-branes compactified on a three torus. Using string theory, we predict that there must be distinct components in the moduli space of this theory.We argue that new superconformal field theories are to be found in these sectors with, for example, global G2 and F4 symmetries. In some cases, twisted E8 5-branes can

A. Kurylov, M. J. Ramsey-Musolf, S. Su

We compute the one-loop supersymmetric (SUSY) contributions to the weak charges of the electron ($Q_W^e$) and proton ($Q_W^p$) using the Minimal Supersymmetric Standard Model (MSSM). These $q^2=0$ vector couplings of the $Z^0$-boson to fermions will be determined in two fixed-target, parity-violating electron scattering experiments. The SUSY loop contributio

Kevork N. Abazajian

New results, namely the independent determination of the deuterium abundance in several quasar absorption systems, and the complementary determination of the cosmological baryon density by observations of anisotropies in the cosmic microwave background (CMB), allow for a reevaluation of the constraints on the relativistic particle content of the universe at

W. G. van der Wiel, S. De Franceschi, J. M. Elzerman, T. Fujisawa

Electron transport experiments on two lateral quantum dots coupled in series are reviewed. An introduction to the charge stability diagram is given in terms of the electrochemical potentials of both dots. Resonant tunneling experiments show that the double dot geometry allows for an accurate determination of the intrinsic lifetime of discrete energy states i

Kazunori Takenaga

Gauge symmetry breaking through the Hosotani mechanism (the dynamics of nonintegrable phases) in softly broken supersymmetric QCD with $N_F^{fd}$ flavors is studied. For $N=$ even, there is a single SU(N) symmetric vacuum state, while for $N=$ odd, there is a doubly degenerate SU(N) symmetric vacuum state in the model. We also study generalized supersymmetri

Simone Severini

Given a matrix M of size n, a digraph D on n vertices is said to be the digraph of M, when M_{ij} is different from 0 if and only if (v_{i},v_{j}) is an arc of D. We give a necessary condition, called strong quadrangularity, for a digraph to be the digraph of a unitary matrix. With the use of such a condition, we show that a line digraph, LD, is the digraph

Ph. de Forcrand, O. Philipsen

We present results on the QCD phase diagram for mu_B <= pi T. Our simulations are performed with an imaginary chemical potential mu_I for which the fermion determinant is positive. On an 8^3 x 4 lattice with 2 flavors of staggered quarks, we map out the phase diagram and identify the pseudo-critical temperature T_c(mu_I). For mu_I/T <= pi/3, this is an analy

K. Haule, A. Rosch, J. Kroha, P. Wölfle

How are the properties of a metal changed by strong inelastic scattering? We investigate this question within the two-dimensional t-J model using extended dynamical mean field theory and a generalized non-crossing approximation. Short-ranged antiferromagnetic fluctuations lead to a strongly incoherent single particle dynamics, large entropy and resistance. C

Andrea Parisi, Robin C. Ball

We show that the delivery of fracture work to the tip of an advancing planar crack is strongly reduced by surface phonon emission, leading to forbidden ranges of crack speed. The emission can be interpreted through dispersion of the group velocity, and Rayleigh and Love branches contribute as well as other high frequency branches of the surface wave dispersi

R. Aloisio, P. Blasi, A. Galante, P. L. Ghia

The intimate geometry of space-time is expected to suffer stochastic fluctuations as a result of quantum gravitational effects. These fluctuations may induce observable consequences on the propagation of high energy particles over large distances, so that the strength and the characteristics of these fluctuations may be constrained, mainly in the range of en

D. Vion, A. Aassime, A. Cottet, P. Joyez

We have designed and operated a superconducting tunnel junction circuit that behaves as a two-level atom: the ``quantronium&#39;&#39;. An arbitrary evolution of its quantum state can be programmed with a series of microwave pulses, and a projective measurement of the state can be performed by a pulsed readout sub-circuit. The measured quality factor of quant

Roberto Auzzi, Kenichi Konishi

Calculation by Douglas and Shenker of the tension ratios for vortices of different N-alities in the softly broken N=2 supersymmetric SU(N) Yang-Mills theory, is carried to the second order in the adjoint multiplet mass m. Corrections to the ratios violating the well-known sine formula are found, showing that it is not a universal quantity.

M. D&#39;Elia, A. Di Giacomo, E. Meggiolaro

We study by numerical simulations on a lattice the behaviour of the gauge-invariant two-point correlation functions of the gauge-field strengths across the deconfinement phase transition, both for the pure-gauge SU(3) theory and for full QCD with two flavours. Quenched data agree within errors with previous determinations, but have much higher statistics. A

Wm. G. Hoover, H. A. Posch, K. Aoki, D. Kusnezov

The dissipation associated with nonequilibrium flow processes is reflected by the formation of strange attractor distributions in phase space. The information dimension of these attractors is less than that of the equilibrium phase space, corresponding to the extreme rarity of nonequilibrium states. Here we take advantage of a simple model for heat conductio

David Wands, Nicola Bartolo, Sabino Matarrese, Antonio Riotto

We study adiabatic and isocurvature perturbation spectra produced by a period of cosmological inflation driven by two scalar fields. We show that there exists a model-independent consistency condition for all two-field models of slow-roll inflation, despite allowing for model-dependent linear processing of curvature and isocurvature perturbations during and

M. J. Griffin, J. J. Bock, W. K. Gear

Modern far infrared and submillimeter instruments require large format arrays. We consider the relative performance of filled array (bare pixel) and feedhorn-coupled architectures for bolometer focal planes. Based on typical array parameters, we quantify the relative observing speeds and comment on the merits of the different architectures. Filled arrays can

Nathan Roche, Omar Almaini, James Dunlop, R. J. Ivison

We investigate the number counts, clustering, morphology and radio/X-ray emission of extremely red objects (EROs), defined as galaxies with R-K>5.0. This criterion will select old, passive ellipticals at z>0.9. To K=21 we identify a total of 158 EROs in 81.5 sq. arcmin. The ERO number counts are lower than predicted by a pure luminosity evolution model, but

A. Nichols

We use the process of quantum hamiltonian reduction of SU(2)_k, at rational level k, to study explicitly the correlators of the h_{1,s} fields in the c_{p,q} models. We find from direct calculation of the correlators that we have the possibility of extra, chiral and non-chiral, multiplet structure in the h_{1,s} operators beyond the `minimal&#39; sector. At

H. B. Nielsen, Y. Takanishi

We develop a model of ours fitting the quark and lepton masses and mixing angles by removing from the model a Higgs field previously introduced to organise a large atmospheric mixing angle for neutrino oscillations. Due to the off-diagonal elements dominating in the see-saw neutrino mass matrix the large atmospheric mixing angle comes essentially by itself.

Jounghun Lee

We present a statistical strategy for the efficient determination of the cluster luminosity function from the Sunyaev-Zel&#39;dovich (SZ) effects survey. To determine the cluster luminosity function from the noise contaminated SZ map, we first define the zeroth-order cluster luminosity function as a discrepancy between the measured peak number density of the

Paola Gori-Giorgi, Paul Ziesche

The momentum distribution of the unpolarized uniform electron gas in its Fermi-liquid regime, n(k,r_s), with the momenta k measured in units of the Fermi wave number k_F and with the density parameter r_s, is constructed with the help of the convex Kulik function G(x). It is assumed that $n(0,r_s), n(1^\pm, r_s)$, the on-top pair density g(0,r_s) and the kin

K. Hammerer, G. Vidal, J. I. Cirac

A non-local unitary transformation of two qubits occurs when some Hamiltonian interaction couples them. Here we characterize the amount, as measured by time, of interaction required to perform two--qubit gates, when also arbitrarily fast, local unitary transformations can be applied on each qubit. The minimal required time of interaction, or interaction cost

K. A. Meissner, H. P. Nilles, M. Olechowski

We investigate the phenomenon of brane induced supersymmetry breakdown on orbifolds in the presence of a Scherk-Schwarz mechanism. General consistency conditions are derived for arbitrary dimensions and the results are illustrated in the specific example of a 5-dimensional theory compactified on $S^1/Z_2$. This includes a discussion of the Kaluza-Klein spect

J. C. Lasjaunias, M. Saint-Paul, A. Bilusic, A. Smontara

We report on extended investigation of the thermal transport and acoustical properties on hard carbon samples obtained by pressurization of C60 fullerene. Structural investigations performed by different techniques on the same samples indicate a very inhomogeneous structure at different scales, based on fractal-like amorphous clusters on the micrometer to su

O. Reimer, M. Pohl

Recent TeV-scale gamma-ray observations with the CANGAROO II telescope have led to the claim that the multi-band spectrum of RX J1713.7-3946 cannot be explained as the composite of a synchrotron and an inverse Compton component emitted by a population of relativistic electrons. It was argued that the spectrum of the high-energy emission is a good match to th

Simon Judes, Matt Visser

Motivated by various theoretical arguments that the Planck energy (Ep - 10^19 GeV) - should herald departures from Lorentz invariance, and the possibility of testing these expectations in the not too distant future, two so-called &#34;Doubly Special Relativity&#34; theories have been suggested -- the first by Amelino-Camelia (DSR1) and the second by Smolin a

N. L. Martin-Hernandez, R. Vermeij, A. G. G. M. Tielens, J. M. van der Hulst

Observations of infrared fine-structure lines provide direct information on the metallicity and ionization structure of HII regions and indirectly on the hardness of the radiation field ionizing these nebulae. We have analyzed a sample of Galactic and Magellanic Cloud HII regions observed by the Infrared Space Observatory (ISO) to examine the interplay betwe

Hiroshi Itoyama, Shin Nakamura

We show that a non-trivial dilaton condensation alters the dimensions of orientifold planes. An off-shell crosscap state which naturally interpolates between the usual on-shell crosscap states and their T-duals plays an important role in the analysis. We present an explicit representation of the off-shell crosscap state on an RP2 worldsheet in the gauge in w

Tetsufumi Hirano, Keiichi Tsuda

We investigate the effect of early chemical freeze-out on radial flow, elliptic flow and HBT radii by using a fully three dimensional hydrodynamic model. When we take account of the early chemical freeze-out, the space-time evolution of temperature in the hadron phase is considerably different from the conventional model in which chemical equilibrium is alwa

A. G. Akeroyd, S. Recksiegel

We study the decays Bu -> l nu and Bc -> l nu in the context of the Minimal Supersymmetric Standard Model (MSSM) with explicit R parity violation. We analyse the correlation between the two decays and show that branching ratios (BRs) for Bc -> l nu may be of order 5% (over 40% in one case), without violating current bounds on Bu -> l nu. Although Bc mesons a

P. T. Cochrane, T. C. Ralph

We introduce a refinement of the standard continuous variable teleportation measurement and displacement strategies. This refinement makes use of prior knowledge about the target state and the partial information carried by the classical channel when entanglement is non-maximal. This gives an improvement in the output quality of the protocol. The strategies

Martin Crocce, Diego A. R. Dalvit, Francisco D. Mazzitelli

We compute the photon creation inside a perfectly conducting, three dimensional oscillating cavity, taking the polarization of the electromagnetic field into account. As the boundary conditions for this field are both of Dirichlet and (generalized) Neumann type, we analyze as a preliminary step the dynamical Casimir effect for a scalar field satisfying gener

T. B. Pittman, B. C. Jacobs, J. D. Franson

We describe the results of a parametric down-conversion experiment in which the detection of one photon of a pair causes the other photon to be switched into a storage loop. The stored photon can then be switched out of the loop at a later time chosen by the user, providing a single photon for potential use in a variety of quantum information processing appl

Serge Massar, Stefano Pironio

We show how to construct Greenberger-Horn-Zeilinger type paradoxes for continuous variable systems. We give two examples corresponding to 3 party and 5 party paradoxes. The paradoxes are revealed by carrying out position and momentum measurements. The structure of the quantum states which lead to these paradoxes is discussed.