December 2001 arXiv papers — page 24

L. W. Garland, T. Gehrmann, E. W. N. Glover, A. Koukoutsakis

We compute the ${\cal O}(α_s^3)$ virtual QCD corrections to the $γ^*\to q\bar q g$ matrix element arising from the interference of the two-loop with the tree-level amplitude and from the self-interference of the one-loop amplitude. The calculation is performed by reducing all loop integrals appearing in the two-loop amplitude to a small set of known master i

F. Bissey, J-J. Dugne, J-F. Mathiot

We calculate the dynamical relativistic corrections, originating from radiative one-gluon-exchange, to the leptonic decay width of heavy quarkonia in the framework of a covariant formulation of Light-Front Dynamics. Comparison with the non-relativistic calculations of the leptonic decay width of J=1 charmonium and bottomonium S-ground states shows that relat

Alexander Burinskii

We consider particlelike solutions to supergravity based on the Kerr-Newman black hole (BH) solution. The BH singularity is regularized by means of a phase transition to a new vacuum state near the core region confining a dual gauge field. Supersymmetric BPS-saturated domain wall model is suggested which can provide this phase transition and formation the st

M. V. N. Murthy, U. A. Yajnik

We have identified some important and worthwhile physics opportunitites with a possible neutrino detector located in India. Particular emphasis is placed on the geographical advantage with a stress on the complimentary aspects with respect to other neutrino detectors already in operation.

S. V. Molodtsov, G. M. Zinovjev

The interaction of light quarks and instanton liquid is analyzed at finite density of quark/baryon matter and in the phase of nonzero values of diquark (colour) condensate. It is shown that instanton liquid perturbation produced by such an interaction results in an essential increase of the critical value of quark chemical potential $μ_c$ which provokes the

Swagato Banerjee

Rapidity gaps have been studied in well separated completely symmetric 3 jet events from hadronic Z decays to search for colour singlet exchange. Asymmetries in particle flow and angular separation, defined with respect to the inter-jet regions, are found to be sensitive to the exchange of a colour singlet object instead of a colour octet gluon. %Comparing d

G. Battistoni, A. Ferrari, T. Montaruli, P. R. Sala

The FLUKA calculation of the atmospheric neutrino fluxes have been cross-checked by comparing predictions on lepton fluxes in atmosphere to experimental data. The dependence of predicted neutrino fluxes on the shape and normalization of primary spectrum is also investigated

Sven Soff

We point out what we may learn from the investigation of identical two-particle interferometry in ultrarelativistic heavy ion collisions if we assume a particular model scenario by the formation of a thermalized quark-gluon plasma hadronizing via a first-order phase transition to an interacting hadron gas. The bulk properties of the two-pion correlation func

J. Erler, K. Flottmann, S. Heinemeyer, K. Monig

The physics potential of an e+e- linear collider can be significantly enhanced if both the electron and positron beams are polarised. Low energy running at the Z-resonance or close to the W-pair threshold is particularly attractive with polarised positrons. This note discusses the experimental aspects and physics opportunities of both low energy running and

Mingzhe Li, Xiulian Wang, Bo Feng, Xinmin Zhang

We propose in this paper a scenario of spontaneous baryogenesis in cosmological models of Quintessence by introducing a derivative coupling of the Quintessence scalar $Q$ to the baryon current $J_B^μ$ or the current of the baryon number minus lepton number $J_{B-L}^μ$. We find that with a dimension-5 operator ${\partial_μQ} J_{B-L}^μ$ suppressed by the Planc

D. T. Son

In this talk I will review some recent progress in our understanding of properties of high density quark matter. This talk is based mainly on the papers hep-ph/0011379, hep-ph/0012041, hep-ph/0108260, and cond-mat/0103451, done in collaboration with D. Rischke, M. Stephanov, and A. Zhitnitsky.

Amol Dighe, Tobias Hurth, Choong Sun Kim, Tadashi Yoshikawa

We estimate $\dg/Γ_d$, including $1/m_b$ contributions and part of the next-to-leading order QCD corrections. We find that adding the latter corrections decreases the value of $\dg/Γ_d$ computed at the leading order by a factor of almost 2. We also show that under certain conditions an upper bound on the value of $\dg/Γ_d$ in the presence of new physics can

Greg Landsberg

If the scale of quantum gravity is near a TeV, the LHC will be producing one black hole (BH) about every second, thus qualifying as a BH factory. With the Hawking temperature of a few hundred GeV, these rapidly evaporating BHs may produce new, undiscovered particles with masses ~100 GeV. The probability of producing a heavy particle in the decay depends on i

Gautier Hamel de Monchenault

Recent experimental results on CP violation in the study of B meson decays are reviewed. The emphasis is put on the recent measurements of the CP parameter sin2beta by the BABAR and BELLE experiments at asymmetric B factories, which establish for the first time CP violation in the B meson system.

Jose B. Almeida

The starting point of this work is the principle that all movement of particles and photons in the observable Universe must follow geodesics of a 4-dimensional space where time intervals are always a measure of geodesic arc lengths, i.e. $c^2(\mathrm{d}t)^2 = g_{αβ} \mathrm{d} x^α\mathrm{d} x^β$, with $c$ is the speed of light in vacuum, $t$ time, $g_{αβ}$ a

Thomas Eiter, Wolfgang Faber, Nicola Leone, Gerald Pfeifer

We propose a new declarative planning language, called K, which is based on principles and methods of logic programming. In this language, transitions between states of knowledge can be described, rather than transitions between completely described states of the world, which makes the language well-suited for planning under incomplete knowledge. Furthermore

Masaki Murata, Hitoshi Isahara

This paper describes a universal model for paraphrasing that transforms according to defined criteria. We showed that by using different criteria we could construct different kinds of paraphrasing systems including one for answering questions, one for compressing sentences, one for polishing up, and one for transforming written language to spoken language.

Masaki Murata, Qing Ma, Hitoshi Isahara

The elastic-input neuro tagger and hybrid tagger, combined with a neural network and Brill's error-driven learning, have already been proposed for the purpose of constructing a practical tagger using as little training data as possible. When a small Thai corpus is used for training, these taggers have tagging accuracies of 94.4% and 95.5% (accounting onl

Masaki Murata, Kiyotaka Uchimoto, Qing Ma, Hitoshi Isahara

This paper describes experiments carried out using a variety of machine-learning methods, including the k-nearest neighborhood method that was used in a previous study, for the translation of tense, aspect, and modality. It was found that the support-vector machine method was the most precise of all the methods tested.

M. E. Larraga, J. A. del Rio

In recent years the modelling of traffic flow using methods from statistical physics, especially cellular automata models have allowed simulations of large traffic networks faster than real time. In this paper, we study a probabilistic cellular automaton model for microsimulations of traffic flow of automated vehicles in highways. This model describes single

V. Kiryukhin, T. Y. Koo, A. Borissov, Y. J. Kim

We report x-ray scattering studies of nanoscale structural correlations in Nd$_{1-x}$Sr$_x$MnO$_3$ and La$_{1-x}$(Ca,Sr)$_x$MnO$_3$, $x$=0.2--0.5. We find that the correlated regions possess a temperature-independent correlation length of 2-3 lattice constants which is the same in all samples. The period of the lattice modulation of the correlated regions is

K. Held, I. A. Nekrasov, G. Keller, V. Eyert

LDA+DMFT is a novel computational technique for ab initio investigations of real materials with strongly correlated electrons, such as transition metals and their oxides. It combines the strength of conventional band structure theory in the local density approximation (LDA) with a modern many-body approach, the dynamical mean-field theory (DMFT). In the last

Belita Koiller, Xuedong Hu, S. Das Sarma

Proposed Silicon-based quantum computer architectures have attracted attention because of their promise for scalability and their potential for synergetically utilizing the available resources associated with the existing infrastructure of the powerful Si technology. Quantitative understanding of and precise physical control over donor (e.g. Phosphorus) exch

A. Sedrakyan

The technique of construction on Manhattan lattice (ML) the fermionic action for Integrable models is presented. The Sign-Factor of 3D Ising model (SF of 3DIM) and Chalker-Coddington-s phenomenological model (CCM) for the edge excitations in Hall effect are formulated in this way. The second one demonstrates the necessity to consider the inhomogeneous models

S. Park, R. L. Leheny, R. J. Birgeneau, J. -L. Gallani

The effect on the nematic to smectic-A transition in octylcyanobiphenyl (8CB) due to dispersions of hydrogen-bonded silica (aerosil) particles is characterized with high-resolution x-ray scattering. The particles form weak gels in 8CB creating a quenched disorder that replaces the transition with the growth of short range smectic correlations. The correlatio

Lyderic Bocquet, Jalal Errami, Tom. C. Lubensky

Granular material on an inclined plane will flow like a fluid if the angle $θ$ the plane makes with the horizontal is large enough. We employ a modification of a hydrodynamic model introduced previously to describe Couette flow experiments to describe chute flow down a plane. In this geometry, our model predicts a jammed-to-flowing transition as $θ$ is incre

L. G. Caron, C. Bourbonnais

We use the Density-Matrix Renormalization Group to study the single-particle and two-particle correlation functions of spinless fermions in the ground state of a quarter-filled ladder. This ladder consists of two chains having an in-chain extended Coulomb interaction reaching to third neighbor and coupled by inter-chain hopping. Within our short numerical co

Akhlesh Lakhtakia

Sculptured thin films (STFs) are nano-engineered materials whose columnar morphology is tailored to elicit desired optical responses upon excitation. Two canonical forms of STFs have been identified. Linear constitutive relations for general STFs as unidirectionally nonhomogeneous (continuously or piecewise uniformly) and locally bianisotropic continuums are

A. Honecker, J. L. Jacobsen, M. Picco, P. Pujol

We study the universality class of the fixed points of the 2D random bond q-state Potts model by means of numerical transfer matrix methods. In particular, we determine the critical exponents associated with the fixed point on the Nishimori line. Precise measurements show that the universality class of this fixed point is inconsistent with percolation on Pot

Sergey K. Nemirovskii, Makoto Tsubota, Tsunehiko Araki

Using the Gaussian model of the vortex tangle (VT) arising in the turbulent superfluid HeII, we calculate the energy spectrum $E(k)$ of the 3D random velocity field induced by that VT. If the VT is assumed to be a purely fractal object with Haussdorf dimension $H_D$, the $E(k)$ is a power-like function $E(k)\propto k^{-2+H_D}$. A more realistic VT in HeII is

Ramaz Khomeriki

Collision process between breather and moving kink-soliton is investigated both analytically and numerically in Fermi-Pasta-Ulam (FPU) chains. As it is shown by both analytical and numerical consideration low amplitude breathers and soft kinks retain their shapes after interaction. Low amplitude breather only changes the location after collision and remains

J. L. Luo, J. W. Loram, T. Xiang, J. R. Cooper

We have measured the electronic specific heat of $Y_{0.8}Ca_{0.2}Ba_2Cu_3O_{7-δ}$ using a high-resolution differential technique from liquid helium temperature to room temperature in an applied magnetic field up to 13T. The field dependence of the electronic specific heat at low temperatures in the superconducting state behaves differently in the overdoped a

D. S. Deng, X. F. Jin, Ruibao Tao

By means of micromagnetic spin dynamics calculations, a quantitative calculation is carried out to explore the mechanism of exchange bias (EB) in ferromagnetic (FM)/compensated antiferromagnetic (AFM) bilayers. The antiferromagnets with low and high Neel temperatures have been both considered, and the crossover from negative to positive EB is found only in t

V. M. Apalkov, M. E. Portnoi

We study the phonon-assisted process of dissociation of a magnetoroton, in a fractional quantum Hall liquid, into an unbound pair of quasiparticles. Whilst the dissociation is forbidden to first order in the electron-phonon interaction, it can occur as a two-phonon process. Depending on the value of final separation between the quasiparticles, the dissociati

Dafang Zheng, Guler Ergun

We introduce and solve a model which considers two coupled networks growing simultaneously. The dynamics of the networks is governed by the new arrival of network elements (nodes) making preferential attachments to pre-existing nodes in both networks. The model segregates the links in the networks as intra-links, cross-links and mix-links. The corresponding

Frank Zielen, Andreas Schadschneider

We consider the asymmetric random average process (ARAP) with continuous mass variables and parallel discrete time dynamics studied recently by Krug/Garcia and Rajesh/Majumdar [both Jrl. Stat. Phys. 99 (2000)]. The model is defined by an arbitrary state-independent fraction density function $ϕ(r)$ with support on the unit interval. We examine the exactness o

A. A. Shashkin, S. V. Kravchenko, T. M. Klapwijk

The critical electron density for the metal-insulator transition in a two-dimensional electron gas can be determined by two distinct methods: (i) a sign change of the temperature derivative of the resistance, and (ii) vanishing activation energy and vanishing nonlinearity of current-voltage characteristics as extrapolated from the insulating side. We find th

P. Hoeflich, C. Gerardy, R. Fesen, S. Sakai

Near-infrared spectra of the subluminous Type Ia SN1999by are presented which cover the time evolution from about 4 days before to 2 weeks after maximum. Analysis of these data was accomplished through the construction of an extended set of delayed detonation (DD) models. The explosion, light curves and spectra including their evolution with time are calcula

Zhongxiang Wang, Deepto Chakrabarty

We report on our search for the optical counterparts of the Southern Hemisphere anomalous X-ray pulsar 1E1048.1-5937 and the radio-quiet neutron stars in supernova remnants Puppis A, RCW 103, and PKS 1209-52. The observations were carried out with the new MIT/CfA MagIC camera on the Magellan-I 6.5 m telescope in Chile. We present deep multiband optical image

Cheongho Han, Byeong-Gon Park, Wonyong Han, Young Woon Kang

If a gravitational microlensing event is caused by a widely separated binary lens and the source approaches both lens components, the source flux is successively magnified by the individual lenses: double microlensing events. If events are observed astrometrically, double lensing events are expected to occur with an increased frequency due to the long range

Jean-Paul Kneib

Gravitational Lensing is a UNIQUE tool to constrain the mass distribution of collapsed structures, this is particularly true for galaxies, either on a case by case basis using multiple images of background sources (such as quasars), or statistically using the so called galaxy-galaxy lensing technique. First, I will present the lensing theory, and then discus

Krzysztof Belczynski, Tomasz Bulik, Bronislaw Rudak

Recently much work in studying Gamma-Ray Burst has been devoted to revealing the nature of outburst mechanism and studies of GRB afterglows. These issues have also been closely followed by the quest for identifying GRB progenitors. In this paper we consider the proposed binary star progenitors of GRBs: white dwarf neutron star binaries, white dwarf black hol

Richard E. Rothschild, Richard E. Lingenfelter, David Marsden

Two lines of thought exist as to the nature of Soft Gamma-ray Repeaters (SGRs) and Anomalous X-ray Pulsars (AXPs). On the one hand,we have neutron stars with super-critical magnetic fields, which spin-down the stars and power the gamma-ray bursts. On the other hand, are neutron stars with typical pulsar magnetic fields, which are spun-down by magnetospheric

Scott J. Kenyon

This paper reviews coagulation models for planet formation in the Kuiper Belt, emphasizing links to recent observations of our and other solar systems. At heliocentric distances of 35-50 AU, single annulus and multiannulus planetesimal accretion calculations produce several 1000 km or larger planets and many 50-500 km objects on timescales of 10-30 Myr in a

Masamune Oguri, Atsushi Taruya, Yasushi Suto, Edwin L. Turner

The distribution of differential time delays Δt between images produced by strong gravitational lensing contains information on the mass distributions in the lensing objects as well as on cosmological parameters such as H_0. We derive an explicit expression for the conditional probability distribution function of time delays P(Δt|θ), given an image separatio

Robert F. Stein, David Bercik, Aake Nordlund

Magneto-convection simulations with two scenarios have been performed: In one, horizontal magnetic field is advected into the computational domain by fluid entering at the bottom. In the other, an initially uniform vertical magnetic field is imposed on a snapshot of non-magnetic convection and allowed to evolve. In both cases, the field is swept into the int

Donald E. Jennings, Drake Deming, George McCabe, Pedro Sada

We have recently developed the capability to make solar vector (Stokes IQUV) magnetograms using the infrared line of MgI at 12.32 microns. On 24 April 2001, we obtained a vector magnetic map of solar active region NOAA 9433, fortuitously just prior to the occurrence of an M2 flare. Examination of a sequence of SOHO/MDI magnetograms, and comparison with groun

Michael Nauenberg

Recent analysis of the Doppler shift oscillations of the light from extra-solar planetary systems indicate that some of these systems have more than one large planet. In this case it has been shown that the masses of these planets can be determined without the familiar ambiguity due to the unknown inclination angle of the plane of the orbit of the central st

O. Richard, G. Michaud, J. Richer, S. Turcotte

Evolutionary models have been calculated for Pop II stars of 0.5 to 1.0$M_\odot$ from the pre-main-sequence to the lower part of the giant branch. Rosseland opacities and radiative accelerations were calculated taking into account the concentration variations of 28 chemical species, including all species contributing to Rosseland opacities in the OPAL tables

G. Chartas, E. Agol, M. Eracleous, G. Garmire

We present results from monitoring of the distant (z = 2.64), gravitationally lensed quasar MG J0414+0534 with the Chandra X-ray Observatory. An Fe Ka line at 6.49 +/- 0.09 keV (rest-frame) with an equivalent width of ~ 190eV consistent with fluorescence from a cold medium is detected at the 99 percent confidence level in the spectrum of the brightest image

S. Cassisi, V. Castellani, S. Degl'Innocenti, G. Piotto

In this paper we investigate the level of agreement between observations and "new" Asymptotic Giant Branch (AGB) models, as produced by updating the physical inputs adopted in previous stellar computations. One finds that the new physics increases the predicted luminosity of Horizontal Branch (HB) and AGB stellar structures by a similar amount, keepi

M. Fellhauer, P. Kroupa

Recent spectroscopic observations of galaxies in the Fornax-Cluster reveal nearly unresolved `star-like&#39; objects with red-shifts appropriate to the Fornax-Cluster. These objects have intrinsic sizes of about 100 pc and absolute B-band magnitudes in the range -14 < M_B < -11.5 mag and lower limits for the central surface brightness mu_B >= 23 mag/arcsec^2

Duncan R. Lorimer, Fernando Camilo, Kiraki Xilouris

We present phase-coherent timing solutions obtained for the first time for 17 pulsars discovered at Arecibo by Hulse & Taylor (1975ab) in a 430-MHz survey of the Galactic plane. This survey remains the most sensitive of the Galactic plane at 430 MHz and has comparable equivalent sensitivity to the 1400-MHz Parkes multibeam survey. Comparing both surveys we f

Livia Origlia, R. Michael Rich, Sandra Castro

Using the NIRSPEC spectrograph at Keck II, we have obtained echelle spectra covering the range 1.5-1.8um for 2 of the brightest giants in Liller 1 and NGC 6553, old metal rich globular clusters in the Galactic bulge. We use spectrum synthesis for the abundance analysis, and find [Fe/H]=-0.3 +/- 0.2 and [O/H]=+0.3 +/- 0.2 dex. The composition of the clusters

G. Duchene, A. M. Ghez, C. McCabe

We obtained new near-infrared images of the prototypical pre-main sequence triple system T Tau, as well as the first resolved medium-resolution spectra of the close pair T Tau S. At the time of our observations, the tight binary had a 13 AU projected separation and showed significant motion since its discovery, three years before. The orbit cannot be strongl

Jerome A. Orosz, Paul J. Groot, Michiel van der Klis, Jeffrey E. McClintock

Optical spectroscopic observations of the companion star (type G8IV to K4III) in the microquasar system XTE J1550-564 reveal a radial velocity curve with a best fitting spectroscopic period of P_sp = 1.552 +/- 0.010 days and a semiamplitude of K_2 = 349 +/- 12 km/s. The optical mass function is f(M) = 6.86 +/- 0.71 solar masses (1 sigma). We tentatively meas

Ian Smail, R. J. Ivison, A. W. Blain, J. -P. Kneib

We present the source catalogue for the SCUBA Lens Survey. We summarise the results of extensive multi-wavelength observations of the 15 submillimetre-selected galaxies in the catalogue, from X-rays to radio. We discuss the main observational characteristics of faint submillimetre galaxies as a population, and consider their interpretation within the framewo

Hideko Nomura

We investigate the structure and the stabilities of a protoplanetary disk, which is heated by viscous process in itself and by its central star. The disk is set to rotate with the Keplerian velocity and has the surface density distribution of the minimum mass solar nebula. We assume the vertical hydrostatic equilibrium and the radiative equilibrium at each p

P. Schipani, D. Mancini

The VST (VLT Survey Telescope) is a 2.6 m class Alt-Az telescope to be installed on Cerro Paranal in the Atacama desert, Northern Chile, in the European Southern Observatory (ESO) site. The VST is a wide-field imaging facility planned to supply databases for the ESO Very Large Telescope (VLT) science and carry out stand-alone observations in the UV to I spec

A. Flores-Tlalpa, J. M. Hernandez, G. Tavares-Velasco, J. J. Toscano

A comprehensive analysis of the lepton flavor violating (LFV) decays Z-->li lj is presented within the effective Lagrangian approach. Both the decoupling and nondecoupling scenarios are explored. The experimental constraints from li --> lj lk \bar{lk} and li -->lj gamma as well as some relationships arising from the gauge invariance of the effective Lagrangi

A. M. Gago, M. M. Guzzo, P. C. de Holanda, H. Nunokawa

What can we learn from solar neutrino observations? Is there any solution to the solar neutrino anomaly which is favored by the present experimental panorama? After SNO results, is it possible to affirm that neutrinos have mass? In order to answer such questions we analyze the current available data from the solar neutrino experiments, including the recent S

Michael J. Quist, Veit Elser

The dynamics of a molecule immersed in a superfluid medium are considered. Results are derived using a classical hydrodynamic approach followed by canonical quantization. The classical model, a rigid body immersed in incompressible fluid, permits a thorough analysis; its effective Hamiltonian generalizes the usual rigid-rotor Hamiltonian. In contrast to the

J. M. F. Maia, J. A. S. Lima

The conditions under which cosmologies driven by time varying cosmological terms can be described by a scalar field coupled to a perfect fluid are discussed. An algorithm to reconstruct potentials dynamically and thermodynamically analogue to given phenomenological $Λ$ models is presented. As a worked example, the deflationary cosmology, which evolves from a

T. Banks, M. Dine, M. R. Douglas

We argue that models in which an observable variation of the fine structure constant is explained by motion of a cosmic scalar field, are not stable under renormalization, and require massive fine tuning that cannot be explained by any known mechanism.

Arieh Konigl, Jonathan Granot

We propose to identify pulsar-wind bubbles (PWBs) as the environment in which the afterglow emission in at least some gamma-ray bursts (GRBs) originates. Such bubbles could naturally account for the high fraction of the internal energy residing in relativistic electrons/positrons ($ε_e$) and the high magnetic-to-internal energy ratio ($ε_B$) that have been i

Abdesselam Arhrib, Dilip Kumar Ghosh, Otto C. W. Kong

We report on the possibility of observing Higgs sector CP violation of the minimal supersymmetric standard model at a hadron machine. The CP phase dependent cross-sections for the $VH_i$ associated production processes are given for the Fermilab Tevatron and CERN LHC. Substantial production cross-sections for channels of all three Higgs bosons simultaneously

Stephane Fidanza

The Seiberg-Witten map links noncommutative gauge theories to ordinary gauge theories, and allows to express the noncommutative variables in terms of the commutative ones. Its explicit form can be found order by order in the noncommutative parameter theta and the gauge potential A by the requirement that gauge orbits are mapped on gauge orbits. This of cours

E. Rossi, D. Lazzati, M. J. Rees

Gamma ray bursts are often modelled as jet-like outflows directed towards the observer; the cone angle of the jet is then commonly inferred from the time at which there is a steepening in the power-law decay of the afterglow. We consider an alternative model in which the jet has a beam pattern where the luminosity per unit solid angle (and perhaps also the i

R. N. Faustov, A. P. Martynenko

The corrections of order (Z alpha)^6m_1/m_2 and (Z alpha)^7 from one-loop two-photon exchange diagrams to the energy spectra of the hydrogenic atoms are calculated with the help of the Taylor expansion of corresponding integrands. The method of averaging the quasipotential over the wave functions in the d-dimensional coordinate space is formulated. The numer

J. Hwang, H. Noh

We consider evolutions of linear fluctuations as the background Friedmann world model goes from contracting to expanding phases through smooth and non-singular bouncing phases. As long as the gravity dominates over the pressure gradient in the perturbation equation the growing-mode in the expanding phase is characterized by a conserved amplitude, we call it

Christian Rummel, Joachim Ankerhold

Based on the path integral representation of the partition function of a many body system with separable two body interaction we propose a systematic extension of the perturbed static path approximation (PSPA) to lower temperatures. Thereby, special attention must be paid to instabilities of the classical mean field solution in functional space that cause di

Antonio O. Bouzas

We give the results of complete analytical computations of two- and three-point loop integrals ocurring in heavy particle theories, with and without velocity change, for arbitrary values of external momenta and masses.

P. C. Stichel

We deform the interaction between nonrelativistic point particles on a plane and a Chern-Simons field to obtain an action invariant with respect to time-dependent area-preserving diffeomorphisms. The deformed and undeformed Lagrangians are connected by a point transformation leading to a classical Seiberg-Witten map between the corresponding gauge fields. Th

L. Pentericci, X. Fan, H. W. Rix, M. A. Strauss

We present new VLT spectroscopic observations of the most distant quasar known, SDSS J1030+0524 at z=6.28 which was recently discovered by the Sloan Digital Sky Survey. We confirm the presence of a complete Gunn-Peterson trough caused by neutral hydrogen in the intergalactic medium. There is no detectable flux over the wavelength range from 8450 to 8710 A. W

Hendryk Pfeiffer

The partition function of the SO(4)- or Spin(4)-symmetric Euclidean Barrett-Crane model can be understood as a sum over all quantized geometries of a given triangulation of a four-manifold. In the original formulation, the variables of the model are balanced representations of SO(4) which describe the quantized areas of the triangles. We present an exact dua

M. Ave, J. A. Hinton, R. A. Vazquez, A. A. Watson

We describe a new approach to establishing the mass composition at high energies. Based on measuring both the vertical and inclined shower rates, it has the potential to distinguish heavy nuclei from light nuclei. We apply the method to Haverah Park data above 10^18 eV to show that, under the assumption that the Quark Gluon String Jet Model correctly describ

Markus H. Thoma

If a quark-gluon plasma is formed in relativistic heavy-ion collisions, there may or may not be a mixed phase of quarks, gluons and hadronic clusters when the critical temperature is reached in the expansion of the fireball. If there is a temperature gradient in the fireball, the hadronic clusters, embedded in the heat bath of quarks and gluons, are subjecte

RD Marks

From the South Pole, microthermal turbulence within a narrow surface boundary layer some 200m thick provides the dominant contribution to the astronomical seeing. We present results for the seeing at a wavelength of 2.4um. The narrow turbulence layer above the site, confined close to the surface, provides greatly superior conditions for adaptive optics corre

Gustav W Delius, Niall J. MacKay

We consider the sine-Gordon and affine Toda field theories on the half-line with classically integrable boundary conditions, and show that in the quantum theory a remnant survives of the bulk quantized affine algebra symmetry generated by non-local charges. The paper also develops a general framework for obtaining solutions of the reflection equation by solv

A. D. Alhaidari

The J-matrix method of scattering is used to obtain analytic expressions for the phase shift of two classes of relativistic exponential-type separable potentials whose radial component is either of the general form r^(n-1)exp(-r) or r^(2n)exp(-r^2), where n = 0, 1, or 2. The rank of these separable potentials is n + 1. The nonrelativistic limit is obtained a

D. Melikhov, S. Simula

The connection between the Feynman triangle diagram and the light-front formalism for spin-0 and spin-1 two-fermion systems is analyzed. It is shown that in the limit q+ = 0 the form factors for both spin-0 and spin-1 systems can be uniquely determined using only the good amplitudes, which are not affected by spurious effects related to the loss of rotationa

Jan Bouda, Vladimir Buzek

We generalize the entanglement swapping scheme originally proposed for two pairs of qubits to an arbitrary number $q$ of systems composed from an arbitrary number $m_j$ of qudits. Each of the system is supposed to be prepared in a maximally entangled state of $m_j$ qudits, while different systems are not correlated at all. We show that when a set $\sum_{j=1}

Hermann Haaf, Dirk Tasche

Credit Suisse First Boston (CSFB) launched in 1997 the model CreditRisk+ which aims at calculating the loss distribution of a credit portfolio on the basis of a methodology from actuarial mathematics. Knowing the loss distribution, it is possible to determine quantile-based values-at-risk (VaRs) for the portfolio. An open question is how to attribute fair Va

G. Mao, H. Stöcker, W. Greiner

We study the bound states of anti-nucleons emerging from the lower continuum in finite nuclei within the relativistic Hartree approach including the contributions of the Dirac sea to the source terms of the meson fields. The Dirac equation is reduced to two Schrödinger-equivalent equations for the nucleon and the anti-nucleon respectively. These two equation

Y. P. Wang

Recent FIR/submm deep surveys revealed large number of ULIGs, which are proposed to lie at z>1, and in normally interacting systems with very dusty environments. We discussed in a previous paper that a population with a fast evolving infrared burst phase triggered by gas rich mergers at z~1 interpreted successfully the steep slope of IRAS 60um counts, leavin

A. D. Alhaidari

SO(2,1) is the symmetry algebra for a class of three-parameter problems that includes the oscillator, Coulomb and Morse potentials as well as other problems at zero energy. All of the potentials in this class can be mapped into the oscillator potential by point canonical transformations. We call this class the &#34;oscillator class&#34;. A nontrivial graded

A. P. Kobushkin, Ya. D. Krivenko

Electron-deuteron elastic scattering data ($A(Q^2)$ and $B(Q^2)$ structure functions and polarization observables $t_{20}$, $t_{21}$ and $t_{22}$) are fit with a model that respects asymptotic properties of pQCD at high momentum transfer. The data analysis shows that pQCD starts from $Q^2=3.5 \rm (GeV/c)^2$. Predictions for the magnetic structure function $B

D. Sornette, A. Helmstetter

We present a new kind of critical stochastic finite-time-singularity, relying on the interplay between long-memory and extreme fluctuations. We illustrate it on the well-established epidemic-type aftershock (ETAS) model for aftershocks, based solely on the most solidly documented stylized facts of seismicity (clustering in space and in time and power law Gut

Yuri A. Rylov

It is shown that the statistical conception of quantum mechanics is dynamical but not probabilistic, i.e. the statistical description in quantum mechanics is founded on dynamics. A use of the probability theory, when it takes place, is auxiliary. Attention is drawn to the fact that in the quantum mechanics there are two different objects: an individual objec

Vasily E. Tarasov

In this paper we generalize the usual model of quantum computer to a model in which the state is an operator of density matrix and the gates are general superoperators (quantum operations), not necessarily unitary. A mixed state (operator of density matrix) of n two-level quantum system (open or closed n-qubit system) is considered as an element of $4^{n}$-d

M. Correggi, G. Morchio

Bohm Mechanics and Nelson Stochastic Mechanics are confronted with Quantum Mechanics in presence of non-interacting subsystems. In both cases, it is shown that correlations at different times of compatible position observables on stationary states agree with Quantum Mechanics only in the case of product wave functions. By appropriate Bell-like inequalities i

Terry Rudolph, Barry C. Sanders

We comment on the theoretical quantum state of a propagating laser field proposed by van Enk and Fuchs [quant-ph/0104036, quant-ph/0111157] and clarify that the multimode description of the propagating laser field does not modify our analysis of continuous variable quantum teleportation [quant-ph/0103147]. Furthermore we point out that the ``complete measure

Toshiki Ide, Holger F. Hofmann, Takayoshi Kobayashi, Akira Furusawa

We investigate the changes to a single photon state caused by the non-maximal entanglement in continuous variable quantum teleportation. It is shown that the teleportation measurement introduces field coherence in the output.

L. M. Castellano, D. M. Gonzalez

Trapped state definition for 3-level atoms in Lambda configuration, is a very restrictive one, and for the case of unpolarized beams, this definition no longer holds.We introduce a more general definition by using a reference frame rotating with the frequency of the control field, obtaining a temporal windowing for the trapped population.This amounts to a ti

G. Fiorentini, L. Okun, M. Vysotsky

By using fundamental units c, h, G as conversion factors one can easily transform the dimensions of all observables. In particular one can make them all ``geometrical&#39;&#39;, or dimensionless. However this has no impact on the fact that there are three fundamental units, G being one of them. Only experiment can tell us whether G is basically fundamental.

L. V. Grigorenko, R. C. Johnson, I. J. Thompson, M. V. Zhukov

In a recent experimental study (Gomez del Campo et al, PRL 86, 43 (2001)) of the reaction 17F(p,2p)16O, two-proton events were measured from excitations near a 1-, E*=6.15 MeV state in 18Ne. We calculate by means of R-matrix theory the resonant two-proton production cross section and branching ratios. We conclude that it is unlikely that two-proton productio

Vladimir Zelevinsky, Alexander Volya

We show and interpret three examples of nontrivial results obtained in numerical simulations of many-body systems: exponential convergence of low-lying energy eigenvalues in the process of progressive truncation of huge shell-model matrices, apparently ordered spectra generated by random interactions, and regular behavior of complex many-body energies in a s

Vladimir Zelevinsky, Alexander Volya

We consider a finite Fermi-system where the residual interactions create a soft mode of the excitation spectrum. Because of the large vibrational amplitude, the standard random phase approximation does not work in this situation. We develop a regular method for constructing the anharmonic potential and illustrate the application of the formalism by a simple

P. Sarriguren, E. Moya de Guerra, A. Escuderos

Beta-decay properties of proton-rich odd-A and even-even Krypton isotopes are studied in the framework of a deformed selfconsistent Hartree-Fock calculation with density-dependent Skyrme forces, including pairing correlations between like nucleons in BCS approximation. Residual spin-isospin interactions are consistently included in the particle-hole and part

R. Lednicky

The possibilities of unlike particle correlations for a study of space--time characteristics of particle production are demonstrated. The correlation data from heavy ion collisions is discussed, particularly - in terms of the transport RQMD and hydrodynamic models. An attention is paid to the relative space-time asymmetries in the production of different par