January 2000 arXiv papers — page 5

E. S. Cheb-Terrab, A. D. Roche

A classification, according to invariant theory, of non-constant invariant Abel ODEs known as solvable and found in the literature is presented. A set of new integrable classes depending on one or no parameters, derived from the analysis of the works by Abel, Liouville and Appell, is also shown. Computer algebra routines were developed to solve ODEs members

David P. Blecher, Vern I. Paulsen

We study the injective envelope I(X) of an operator space X, showing amongst other things that it is a self-dual C$^*-$module. We describe the diagonal corners of the injective envelope of the canonical operator system associated with X. We prove that if X is an operator $A-B$-bimodule, then A and B can be represented completely contractively as subalgebras

Mircea Mustata

For a reduced monomial ideal B in R=k[X_1,...,X_n], we write H^i_B(R) as the union of {Ext^i(R/B^[d],R)}_d, where {B^[d]}_d are the "Frobenius powers of B". We describe H^i_B(R)_p, for every p in Z^n, in the spirit of the Stanley-Reisner theory. As a first application we give an isomorphism Tor_i(B', k)_p\iso Ext^{|p|-i}(R/B,R)_{-p} for all p in

Ajneet Dhillon

Given a smooth projective curve $C$ of genus $g$ over the complex numbers, Torelli's thoerem asserts that the pair $(J(C),W^{g-1})$ determines $C$, where $W^{g-1}$ is an image of the $g-1$st symmetric power of $C$ inside the Jacobian under an Abel-Jacobi map. We show that the theorem holds with $g-1$ replaced by an integer $d$ in the range $1\le d\le g-1

David M. J. Calderbank

All local solutions of the two dimensional Einstein-Weyl equations are found, and related to the compact examples which I obtained in "Moebius structures and two dimensional Einstein-Weyl geometry" J. reine angew. Math. 504 (1998).

Birant Ramazan

For a Lie groupoid G we prove an analogous of the Baker-Campbell-Hausdorff formula and we calculate the structure functions of the Lie algebroid associated to G.

Guillermo Cortiñas, Fabiana Krongold

This article concerns commutative algebras over a field $k$ of characteristic zero which are finite dimensional as vectorspaces, and particularly those of such algebras which are graded. Here the term graded is applied to non-negatively graded algebras $A$ with $A_0$ reduced and finite dimensional. Thus the trivial grading $A=A_0$ is only allowed if $A$ is a

Guillermo Cortiñas

We consider commutative algebras and chain DG algebras over a fixed commutative ground ring $k$ as in the title. We are concerned with the problem of computing the cyclic (and Hochschild) homology of such algebras via free DG-resolutions $ΛV @>>> A$. We find spectral sequences $$E^2_{p,q}=H_p(ΛV\otimesΓ^q(dV))\Rightarrow HH_{p+q}(ΛV)$$ and $${E'}^2_{\pq}

Ashok Kumar Mittal, Ashok Kumar Gupta

The roots of any polynomial of degree m with integer coefficients, can be computed by manipulation of sequences made from 2m distinct symbols and counting the different symbols in the sequences. This method requires only 'primitive' operations like replacement of sequences and counting of symbols. No calculations using 'advanced' operations l

Yuri G. Prokhorov

We verify a special case of V. V. Shokurov's conjecture about characterization of toric varieties. More precisely, let $(X,D=\sum d_iD_i)$ be a three-dimensional log variety such that $K_X+D$ is numerically trivial and $(X,D)$ has only purely log terminal singularities. In this situation we prove the inequality \{center} $\sum d_i\le \rk\Weil(X)/(\operat

A. Ghosh, G. Pollifrone, G. Veneziano

The quantum fluctuations of a homogeneous, isotropic, open pre-big bang model are discussed. By solving exactly the equations for tensor and scalar perturbations we find that particle production is negligible during the perturbative Pre-Big Bang phase.

Marco Picariello, Andrea Quadri

We study the Slavnov-Taylor Identities (STI) breaking terms, up to the second order in perturbation theory. We investigate which requirements are needed for the first order Wess-Zumino consistency condition to hold true at the next order in perturbation theory. We find that: a) If the cohomologically trivial contributions to the first order ST breaking terms

P. Bantay

The "orbifold covariance principle", or OCP for short, is presented to support a conjecture of Pradisi, Sagnotti and Stanev on the expression of the Klein- bottle amplitude.

G. Feverati

In this thesis, we review recent progresses on Nonlinear Integral Equation approach to finite size effects in two dimensional integrable quantum field theories, with emphasis to Sine-Gordon/Massive Thirring model and restrictions to minimal models perturbed by $Φ_{1,3}$. Exact calculations of the dependence of energy levels on the size are presented for vacu

W. Dittrich, R. Shaisultanov

Motivated by several recent papers on string-inspired calculations in QED, we here present our own use of world-line techniques in order to calculate the vacuum polarization and effective action in scalar and spinor QED with external arbitrary constant electromagnetic field configuration.

Kingman Cheung

We discuss the physics potential of the $μp$ collider; especially, leptoquarks, leptogluons, R-parity violating squarks, contact interactions, and large extra dimensions. We calculate the sensitivity reach for these new physics at $μp$ colliders of various energies and luminosities.

K. Goeke, P. V. Pobylitsa, M. V. Polyakov, P. Schweitzer

In the framework of the chiral quark-soliton model of the nucleon we investigate the properties of the polarized quark distribution. In particular we analyse the so called anomalous difference between the representations of the quark distribution functions in terms of occupied and non-occupied quark states. By an explicit analytical calculation it is shown t

E. R. Berger, A. Donnachie, H. G. Dosch, O. Nachtmann

We calculate high-energy photoproduction of the tensor meson $f_2(1270)$ by odderon and photon exchange in the reaction $γ+ {\rm{p}} \to f_2(1270) + {\rm{X}}$, where X is either the nucleon or the sum of the N(1520) and N(1535) baryon resonances. Odderon exchange dominates except at very small transverse momentum, and we find a cross section of about 20 nb a

G D'Agostini, G. Degrassi

We show that the likelihood ratio of Higgs search experiments is a form to report the experimental results suitable to be combined with the information from precision measurements to obtain a joint constraint on the Higgs mass. We update our previous combined analysis using the new results on direct searches and recent precision measurements, including also

Mihoko M. Nojiri, Daisuke Toya, Tomio Kobayashi

We study the distribution of lepton pairs from the second lightest neutralino decay \tildeχ^0_2-->\tilde{l}l followed by \tilde{l}\to \tildeχ^0_1 l. The distribution of the ratio of lepton transverse momenta A_T shows peak structure if m_{ll}< m^{max}_{ll}/2 is required. The peak position A_T^{peak} is described by a simple function of the ino and slepton ma

Junegone Chay

Nonleptonic decays B to D pi- or B to D* pi- are dominated by factorizable contributions. In the heavy quark limit, nonfactorizable contribution arises from strong radiative correction and power corrections in 1/m_b. I calculate the decay rates for B to D(*) pi- at next-to-leading order in strong interaction, including nonfactorizable corrections. The result

Frank E. Paige, James Wells

Anomaly Mediated SUSY Breaking models are reviewed. Possible signatures at the LHC for one case of the minimal realistic model are examined.

Andrei V. Afanasev, V. D. Afanasev, S. V. Trubnikov

Relativistic integral representation in terms of experimental neutron-proton scattering phase shifts is used to compute the charge form factor of the deuteron $ G_{Cd}(Q^2)$. The results of numerical calculations of $|G_{Cd}(Q^2)|$ are presented in the interval of the four-momentum transfers squared $0 \leq Q^2 \leq 35 fm^{-2}$. Zero and the prominent second

T. Fujiwara, H. Suzuki, K. Wu

Configuration space of abelian gauge theory on a periodic lattice becomes topologically disconnected by excising exceptional gauge field configurations. It is possible to define a U(1) bundle from the nonexceptional link variables by a smooth interpolation of the transition functions. The lattice analogue of Chern character obtained by a cohomological techni

Sukratu Barve, T. P. Singh, Cenalo Vaz

We prove that the quantum stress tensor for a massless scalar field in two dimensional non-selfsimilar Tolman Bondi dust collapse and Vaidya radiation collapse models diverges on the Cauchy horizon, if the latter exists. The two dimensional model is obtained by suppressing angular co-ordinates in the corresponding four dimensional spherical model.

Avraham E. Mayo

We illustrate how Hawking&#39;s radiance from a Schwarzschild black hole is modified by the electrostatic self-interaction of the emitted charged particles. A W.K.B approximation shows that the probability for a self-interacting charged particle to propagate from the interior to the exterior of the horizon is increased relative to the corresponding probabili

Cristopher Moore, M. E. J. Newman

We study percolation on small-world networks, which has been proposed as a simple model of the propagation of disease. The occupation probabilities of sites and bonds correspond to the susceptibility of individuals to the disease and the transmissibility of the disease respectively. We give an exact solution of the model for both site and bond percolation, i

V. I. Marconi, S. Candia, P. Balenzuela, H. Pastoriza

We study the dependence of the transport properties of square Josephson Junctions arrays with the direction of the applied dc current, both experimentally and numerically. We present computational simulations of current-voltage curves at finite temperatures for a single vortex in the array ($Ha^2/Φ_0=f=1/L^2$), and experimental measurements in $100\times1000

Byounghak Lee, T. Jungwirth, A. H. MacDonald

We present a mean field theory of ferromagnetism in diluted magnetic semiconductor quantum wells. When subband mixing due to exchange interactions between quantum well free carriers and magnetic impurities is neglected, analytic result can be obtained for the dependence of the critical temperature and the spontaneous magnetization on the distribution of magn

Robert Shrock

We present exact calculations of the partition function $Z$ of the $q$-state Potts model and its generalization to real $q$, the random cluster model, for arbitrary temperature on $n$-vertex ladder graphs with free, cyclic, and Möbius longitudinal boundary conditions. These partition functions are equivalent to Tutte/Whitney polynomials for these graphs. The

M. I. Marques, J. A. Gonzalo, J. Iniguez

The universality class of thermally diluted Ising systems, in which the realization of the disposition of magnetic atoms and vacancies is taken from the local distribution of spins in the pure original Ising model at criticality, is investigated by finite size scaling techniques using the Monte Carlo method. We find that the critical temperature, the critica

Piotr Bialas

We analyze correlation functions in a toy model of a random geometry interacting with matter. We show that in general the connected correlator will contain a long--range scaling part. This result supports the previously conjectured general form of correlation functions on random geometries. We discuss the interplay between matter and geometry and the role of

D. Foerster

It was observed previously that an SU(N) extension of the Hubbard model is dominated, at large N, by planar diagrams in the sense of &#39;t Hooft, but the possibility of superconducting pairing got lost in this extrapolation. To allow for this possibility, we replace SU(N) by U(N,q), the unitary group in a vector space of quaternions. At the level of the fre

Vladislav Popkov, Ingo Peschel

We generalize a recently introduced traffic model, where the statistical weights are associated with whole trajectories, to the case of two-way flow. An interaction between the two lanes is included which describes a slowing down when two cars meet. This leads to two coupled five-vertex models. It is shown that this problem can be solved by reducing it to tw

A. Emperador, M. Pi, M. Barranco, E. Lipparini

We have investigated the far-infrared dipole modes of a quantum antidot submitted to a perpendicularly applied magnetic field B. The ground state of the antidot is described within local spin-density functional theory, and the spectrum within time-dependent local spin-density functional theory. The results are compared with those corresponding to a quantum d

T. Felbinger, L. Santos, M. Wilkens, M. Lewenstein

We analyze the multi-time correlations of a laser-induced Bose-Einstein condensate. We use quantum stochastic methods to obtain under certain circumstances a Fokker-Planck equation which describes the phase-difussion process, and obtain an analytical expression of the two-time correlations. We perform also quantum Monte Carlo numerical simulations of the cor

K. J. Veenstra, A. V. Petukhov, E. Jurdik, Th. Rasing

Spectroscopic magnetization induced optical Second Harmonic Generation (MSHG) measurements from a clean Ni(110) surface reveal strong resonance effects near 2.7 eV that can be attributed to the presence of an empty surface state. The good agreement with model calculations shows the potential of MSHG to probe spin polarized interface band structures.

Joachim Ankerhold, Hermann Grabert

The time dependent density matrix of a system with potential barrier is studied using path integrals. The characterization of the initial state, which is assumed to be restricted to one side of the barrier, and the time evolution of the density matrix lead to a three-fold path integral which is evaluated in the semiclassical limit. The semiclassical trajecto

R. J. Ormeno, C. E. Gough, G. Yang

The complex surface impedance of a number of GdBa$_2$Cu$_3$O$_{7-δ}$ single crystals has been measured at 10, 15 and 21 GHz using a cavity perturbation technique. At low temperatures a marked increase in the effective penetration depth and surface resistance is observed associated with the paramagnetic and antiferromagnetic alignment of the Gd spins. The eff

S. A. Crooker, N. Samarth, D. D. Awschalom

Spin clustering in diluted magnetic semiconductors (DMS) arises from antiferromagnetic exchange between neighboring magnetic cations and is a strong function of reduced dimensionality. Epitaxially-grown single monolayers and abrupt interfaces of DMS are, however, never perfectly two-dimensional (2D) due to the unavoidable inter-monolayer mixing of atoms duri

R. Mulet, E. Altshuler

The importance of the distribution and ``weakness&#39;&#39; of grain boundary junctions in the magnetic field dependence of the transport critical current in HTc films is assessed through simulations. The system is studied with the applied field either parallel or perpendicular to the c axis of the sample. For realistic sample parameters, it is demonstrated

Simone Marri, Andrea Ferrara, Lucia Pozzetti

We derive the expected Type II SN differential number counts, N(m), and Hubble diagram for SCDM and LCDM cosmological models, taking into account the effects of gravitational lensing (GL) produced by the intervening cosmological mass. The mass distribution of dark matter halos (ie the lenses) is obtained by means of a Monte Carlo method applied to the Press-

A. Aparicio, N. Tikhonov

The spatial distribution of stellar populations, the star formation history, and other properties of the dIrr galaxy DDO 190 have been analyzed using color--magnitude diagrams (CMDs) of about 3900 resolved stars and the Ha fluxes of HII regions. From the mean color index of the red giant branch, a mean metallicity [Fe/H]=-2.0 is obtained. The I magnitude of

K. Schertler, C. Greiner, J. Schaffner-Bielich, M. H. Thoma

The appearance of quark phases in the dense interior of neutron stars provides one possibility to soften the equation of state (EOS) of neutron star matter at high densities. This softening leads to more compact equilibrium configurations of neutron stars compared to pure hadronic stars of the same mass. We investigate the question to which amount the compac

R. Ramaty, R. E. Lingenfelter, B. Kozlovsky

We consider the three principal LiBeB evolutionary models, CRI in which the cosmic-ray source at all epochs of Galactic evolution is the average ISM, CRI+LECR in which metal enriched low energy cosmic rays (LECRs) are superimposed onto the CRI cosmic rays, and CRS in which the cosmic-ray source, accelerated in superbubbles, is constant, independent of the IS

Titus J. Galama

I review gamma-ray burst optical/multiwavelength afterglow observations since 1997, when the first counterparts to GRBs were discovered. I discuss what we have learned from multiwavelength observations of GRB afterglows in relation to the `standard&#39; fireball plus relativistic blast-wave models. To first order the `standard&#39; model describes the afterg

Franziska Brachwitz, David J. Dean, W. Raphael Hix, Koichi Iwamoto

The Chandrasekhar mass model for Type Ia Supernovae (SNe Ia) has received increasing support from recent comparisons of observations with light curve predictions and modeling of synthetic spectra. It explains SN Ia events via thermonuclear explosions of accreting white dwarfs in binary stellar systems, being caused by central carbon ignition when the white d

Ian A. Bonnell

Observations have revealed that most stars are born in clusters. As these clusters typically contain more mass in gas than in stars, accretion can play an important role in determining the final stellar masses. Numerical simulations of gas accretion in stellar clusters have found that the stars compete for the available reservoir of gas. The accretion rates

G. Helou, N. Y. Lu, M. W. Werner, S. Malhotra

The mid-infrared spectra (2.5 to 5 and 5.7 to 11.6 mu) obtained by ISO-PHOT reveal the interstellar medium emission from galaxies powered by star formation to be strongly dominated by the aromatic features at 6.2, 7.7, 8.6 and 11.3 mu. Additional emission appears in-between the features, and an underlying continuum is clearly evident at 3-5 mu. This continuu

Hale Bradt, Alan M. Levine, Ronald A. Remillard, Donald A. Smith

We present light curves of a sample of &#34;transient&#34; sources observed with the All-Sky Monitor (ASM) of the Rossi X-ray Timing Explorer (RXTE). The light curves extend over 3.5 years. They are presented in three groups: six neutron-star systems, eight black-hole-candidate systems, and an additional diverse set of six objects that are either transient s

Andy Thean, Alan Pedlar, Marek J. Kukula, Stefi A. Baum

We present 8.4 GHz VLA A-configuration observations of 87 sources from the mid-infrared-selected AGN sample of Rush et al (1993). These 0.25 arcsec resolution observations allow elongated radio structures tens of parsecs in size to be resolved and enable radio components smaller than 3.5 arcsec to be isolated from diffuse galactic disc emission. When combine

H. C. Spruit, F. Haardt

The X-ray spectrum from a cool disk embedded in an ion supported torus is computed. The interaction of the hot ions with the disk increases the hard X-ray luminosity of the system}. A surface layer of the disk is heated by the protons from the torus. The Comptonized spectrum produced by this layer has a shape that depends only weakly on the incident energy f

Massimo Turatto

We present and discuss the most recent determination of the rate of Supernovae in the local Universe. A comparison with other results shows a general agreement on the gross values but still significant differences on the values of the rates of various SN rates in different kinds of galaxies. The rate of SNe, used as a probe of Star Formation, confirms the yo

Fronefield Crawford, Victoria M. Kaspi, Jon F. Bell

We have searched 92 unidentified sources from the FIRST and NVSS 1400 MHz radio survey catalogs for radio pulsations at 610 MHz. The selected radio sources are bright, have no identification with extragalactic objects, are point-like and are more than 5% linearly polarized. Our search was sensitive to sub-millisecond pulsations from pulsars with dispersion m

Kristy K. Dyer, Stephen P. Reynolds, Kazik J. Borkowski

Low frequency observations at 330 and 74 MHz can provide new insights into supernova remnants (SNR). We can test theoretical predictions for spectral index variations. Nonlinear models of shock acceleration predict that the spectra from young SNR should be slightly concave rather than power laws -- flattening toward higher energies. However, few SNR are brig

F. Eisenhauer, M. Tecza, N. Thatte, S. Mengel

Integral-field-spectroscopy and multi-object-spectroscopy provide the high multiplex gain required for efficient use of the upcoming generation of extremely large telescopes. We present instrument developments and designs for both concepts, and how these designs can be applied to cryogenic near-infrared instrumentation. Specifically, the fiber-based concept

A. Loinger

According to a widespread idee fixe, the spherically-symmetric collapse of a sufficiently massive celestial body of spherical shape should generate a black hole. I prove that this process generates simply an ordinary point mass. My argument is model-independent.

Yoshiaki Taniguchi, Takashi Murayama, Hideaki Mouri

Dusty tori around active galactic nuclei (AGNs) play an important role in the classification of Seyfert galaxies. Therefore, physical properties of dusty tori are of great interest. We briefly introduce three statistical studies investigating properties of dusty tori; 1) physical sizes of dusty tori based on water-vapor maser emission, 2) ionization conditio

Youichi Ohyama, Michitoshi Yoshida, Tadafumi Takata, Masatoshi Imanishi

We have performed a long-slit K band spectroscopic observation of the luminous infrared galaxy NGC 6240. The peak position of the H_2 v=1-0 S(1) emission in the slit is located ~0.3&#34; - 0.4&#34; north of the southern nucleus. It is almost the midpoint between the southern nucleus and the peak position of the ^12CO J=1-0 emission. Based on the line-ratio a

M. Gilfanov, E. Churazov, M. Revnivtsev

Using the RXTE/PCA data we study the fast variability of the reflected emission in the soft spectral state of Cyg X-1 by means of Fourier frequency resolved spectroscopy. We find that the rms amplitude of variations of the reflected emission has the same frequency dependence as the primary radiation down to time scales of <30-50 msec. This might indicate tha

F. Govoni, R. Falomo, G. Fasano, R. Scarpa

Optical imaging observations for 50 radio galaxies are presented. For each object isophotal contours, photometric profiles, structural parameters (position angle, ellipticity, Fourier coefficients), and total magnitudes are given. These observations, obtained in the Cousins R band, complement the data presented in a previous paper and are part of a larger pr

Wolfgang Vieser, Gerhard Hensler

2d hydrodynamical simulations are performed to examine the evaporation and condensation processes of giant molecular clouds in the hot phase of the interstellar medium. The evolution of cold and dense clouds is calculated in the subsonic stream of a hot tenuous plasma. Our code includes self-gravity, heating and cooling processes and heat conduction by elect

Tomoyuki Hanawa, Tomoaki Matsumoto

We investigate stability of a gravitationally collapsing iron core against non-spherical perturbation. The gravitationally collapsing iron core is approximated by a similarity solution for dynamically collapsing polytropic gas sphere. We find that the similarity solution is unstable against non-spherical perturbations. The perturbation grows in proportion to

Myeong-Gu Park, Jeremiah P. Ostriker

All high temperature accretion solutions including ADAF are physically thick, so outgoing radiation interacts with the incoming flow, sharing as much or more resemblance with classical spherical accretion flows as with disk flows. We examine this interaction for the popular ADAF case. We find that without allowance for Compton preheating, a very restricted d

L. Ji, Y. Chen, J. H. Huang, Q. S. Gu

We find that a preliminary classification of LINERs&#39; energetics may be made in terms of the FIR-radio correlation of Wolf-Rayet galaxies. The AGN- or starburst-supported LINERs can be distinguished by their FIR-to-radio ratio, $Q\equiv L(1.4{\rm GHz})/$ $L(60μ{\rm m})>$ or $<0.01$. It is interesting to note that almost all the LINERs with inner rings mig

Sarbani Basu, H. M. Antia

Using data from the Global Oscillations Network Group (GONG) that covers the period from 1995 to 1998 we study the change in frequencies of solar oscillations with solar activity. From these frequencies we attempt to determine any possible variation in solar structure with solar activity. We do not find any evidence of a change in the convection zone depth o

James Hormuzdiar, Stephen D. H. Hsu, Gregory Mahlon

We investigate the conditions under which particle multiplicities in high energy collisions are Boltzmann distributed, as is the case for hadron production in e^+e^-, pp, p-pbar and heavy ion collisions. We show that the apparent temperature governing this distribution does not necessarily imply equilibrium (thermal or chemical) in the usual sense, as we exp

A. Zheludev, T. Masuda, I. Tsukada, Y. Uchiyama

Two quasi-1-dimensional S=1 quantum antiferromagnetic materials, PbNi2V2O8 and SrNi2V2O8, are studied by inelastic neutron scattering on powder samples. While magnetic interactions in the two systems are found to be very similar, subtle differences in inter-chain interaction strengths and magnetic anisotropy are detected. The latter are shown to be responsib

Laurent Houart, Yolanda Lozano

We discuss how the BPS branes of M-theory could be described as bound states of non-BPS M10-branes. This conjectured M10-brane is constructed as an unstable spacetime-filling brane in the massive eleven dimensional supergravity defined with a Killing direction, such that 1) the BPS M9-brane is obtained after the tachyonic mode of an M2-brane ending on it con

Christopher T. Hill, Leon M. Lederman

Modern physics is largely defined by fundamental symmetry principles and Noether&#39;s Theorem. Yet these are not taught, or rarely mentioned, to beginning students, thus missing an opportunity to reveal that the subject of physics is as lively and contemporary as molecular biology, and as beautiful as the arts. We prescribe a symmetry module to insert into

Zoltan Kollath, J. Robert Buchler, Michael Feuchtinger

The luminosities, effective temperatures and metallicities that are derived empirically by Kovacs and Jurcsik from the light curves of a large number of globular cluster and field RRab and RRc stars are compared to theoretical RR Lyrae models. The strong luminosity dependence of the empirical blue and red edges (Log L vs Log Teff diagram) is in disagreement

P. S. Howe, A. Kaya, E. Sezgin, P. Sundell

We study codimension one branes, i.e. p-branes in (p+2)-dimensions, in the superembedding approach for the cases where the worldvolume superspace is embedded in a minimal target superspace with half supersymmetry breaking. This singles out the cases p=1,2,3,5,9. For p=3,5,9 the superembedding geometry naturally involves a fundamental super 2-form potential o

Bruce A. Bassett, Stefano Liberati, Carmen Molina-Paris, Matt Visser

This paper is dedicated to the memory of Dennis Sciama. Variable-Speed-of-Light (VSL) cosmologies are currently attracting interest as an alternative to inflation. We investigate the fundamental geometrodynamic aspects of VSL cosmologies and provide several implementations which do not explicitly break Lorentz invariance (no &#34;hard&#34; breaking). These &

L. Forro, R. Gaal, H. Berger, P. Fazekas

The phase diagram of BaVS3 is studied under pressure using resistivity measurements. The temperature of the metal to nonmagnetic Mott insulator transition decreases under pressure, and vanishes at the quantum critical point p_cr=20kbar. We find two kinds of anomalous conducting states. The high-pressure metallic phase is a non-Fermi liquid described by Delta

Ilki Kim, Guenter Mahler

We study a two-spin quantum Turing architecture, in which discrete local rotations α_m of the Turing head spin alternate with quantum controlled NOT-operations. Substitution sequences are known to underlie aperiodic structures. We show that parameter inputs α_m described by such sequences can lead here to a quantum dynamics, intermediate between the regular

H A Carteret, A Sudbery

Entanglement types of pure states of 3 qubits are classified by means of their stabilisers in the group of local unitary operations. It is shown that the stabiliser is generically discrete, and that a larger stabiliser indicates a stationary value for some local invariant. We describe all the exceptional states with enlarged stabilisers.

Torsten A. Ensslin, Christian R. Kaiser

(Abridged) We investigate the spectral distortion of the cosmic microwave background (CMB) caused by relativistic plasma. Within the Thomson regime, an exact analytic expression for the photon scattering kernel of a momentum power-law electron distribution is given. The ultra-relativistic Sunyaev-Zeldovich (SZ) decrement measures the electron number and not

M. M. Sheikh-Jabbari

In this paper we study the invariance of the noncmmutative gauge theories under C, P and T transformations. For the noncommutative space (when only the spatial part of $θ$ is non-zero) we show that NCQED is Parity invariant. In addition, we show that under charge conjugation the theory on noncommutative $R^4_θ$ is transformed to the theory on $R^4_{-θ}$, so

D. Novikov, P. Naselsky, H. E. Jorgensen, P. R. Christensen

We propose a power filter Gp for linear reconstruction of the CMB signal from observational maps. This Gp filter preserves the power spectrum of the CMB signal in contrast to the Wiener filter which diminishes the power spectrum of the reconstructed CMB signal. We demonstrate how peak statistics and a cluster analysis can be used to estimate the probability

M. Oettel, R. Alkofer

In the diquark-quark model of the nucleon including scalar and axialvector diquarks we compare solutions of the ladder Bethe-Salpeter equation in the instantaneous Salpeter approximation and in the fully covariant (i.e. four-dimensional) treatment. We obtain that the binding energy is severly underestimated in the Salpeter approximation. For the electromagne

Jesper Lykke Jacobsen

We establish explicit duality transformations for systems of M q-state Potts models coupled through their local energy density, generalising known results for M=1,2,3. The M-dimensional space of coupling constants contains a selfdual sub-manifold of dimension D_M = [M/2]. For the case M=4, the variation of the effective central charge along the selfdual surf

L. Angelani, M. Montagna, G. Ruocco, G. Viliani

Three classes of harmonic disorder systems (Lennard-Jones like glasses, percolators above threshold, and spring disordered lattices) have been numerically investigated in order to clarify the effect of different types of disorder on the mechanism of high frequency sound attenuation. We introduce the concept of frustration in structural glasses as a measure o

Bo-Qiang Ma, Ivan Schmidt, Jacques Soffer, Jian-Jun Yang

The flavor and helicity distributions of the $Λ$ and $\barΛ$ hyperons for both valence and sea quarks are calculated in a perturbative QCD (pQCD) based model. We relate these quark distributions to the fragmentation functions of the $Λ$ and $\barΛ$, and calculate the $z$-dependence of the longitudinal spin transfer to the $Λ$ and $\barΛ$ in lepton deep-inela

D. Yu. Ivanov, R. Kirschner, A. Schäfer, L. Szymanowski

We have studied in perturbative QCD all independent helicity amplitudes describing the photoproduction of light vector mesons at large $t$. We found a new hard production mechanism which is related to the possibility for a real photon to fluctuate into a massless $q\bar q$ pair in a chiral-odd spin configuration. Each helicity amplitude is given as a sum of

Naoki Sasakura

We discuss a Lorentz covariant space-time uncertainty relation, which agrees with that of Karolyhazy-Ng-van Dam when an observational time period delta t is larger than the Planck time lp. At delta t < lp, this uncertainty relation takes roughly the form delta t delta x > lp^2, which can be derived from the condition prohibiting the multi-production of probe

O. I. Piskounova

The comparison of B-meson production cross sections as the results of PYTHIA code and Quark Gluon String Model (QGSM) is carried out for energies of proton colliders: $Sp\bar(p)S$, Tevatron and LHC. Model predictions are based on the theory of supercritical Pomeron exchanges with the phenomenological intercept $Δ_P$(0)=0.3, accepted for heavy quark productio

Rong Lu, Jia-Lin Zhu, Yi Zhou, Bing-Lin Gu

We present an exact analytic study on the topological phase interference effect in resonant quantum tunneling of the magnetization between degenerate excited levels for biaxial ferromagnets in an arbitrarily directed magnetic field. We show that the topological phase interference effect depends on the orientation of the field distinctly. The transition from

Robert B. Griffiths

A recent claim by Bassi and Ghirardi that the consistent (decoherent) histories approach cannot provide a realistic interpretation of quantum theory is shown to be based upon a misunderstanding of the single-framework rule: they have replaced the correct rule with a principle which directly contradicts it. It is their assumptions, not those of the consistent

Vladimir L. Ermakov, Alexander R. Kessel, Vitaly V. Samartsev

It is proposed to use four atomic optical energy levels as a two qubit quantum register. A single Pr3+ atom in a monocrystal LaF3 subjected to resonant laser irradiation is used as an example to illustrate the implementation of the universal set of quantum gates. The equilibrium state of this physical system is a desirable input state for quantum computation

Sergio Albeverio, Ludwik Dabrowski, Shao-Ming Fei

The integrability of one dimensional quantum mechanical many-body problems with general contact interactions is extensively studied. It is shown that besides the pure (repulsive or attractive) $δ$-function interaction there is another singular point interactions which gives rise to a new one-parameter family of integrable quantum mechanical many-body systems

W. T. Buttler, R. J. Hughes, S. K. Lamoreaux, G. L. Morgan

Quantum key distribution (QKD) has been demonstrated over a point-to-point $\sim1.6$-km atmospheric optical path in full daylight. This record transmission distance brings QKD a step closer to surface-to-satellite and other long-distance applications.

Lester Ingber

A non Monte Carlo path-integral algorithm that is particularly adept at handling nonlinear Lagrangians is extended to multivariate systems. This algorithm is particularly accurate for systems with moderate noise.

G. Van Hooydonk

Following recent work in search of a universal function (Van Hooydonk, Eur J Inorg Chem, 1999, 1617), we test symmetric potentials for reproducing molecular potential energy curves (PECs). For a bond, a four-particle system, charge inversion is the key to explain this shape generically. A parity adapted Hamiltonian reduces from ten to two terms. The analytic

V. A. Dzuba, V. V. Flambaum, C. Harabati

Positron binding to silver and gold atoms was studied using a fully {\it ab initio} relativistic method, which combines the configuration interaction method with many-body perturbation theory. It was found that the silver atom forms a bound state with a positron with binding energy 123 ($\pm$ 20%) meV, while the gold atom cannot bind a positron. Our calculat

G. Baur, S. Typel, H. H. Wolter, K. Hencken

We review some simple mechanisms of breakup in nuclear reactions. We mention the spectator breakup, which is described in the post-form DWBA. The relation to other formulations is also indicated. An especially important mechanism is Coulomb dissociation. It is a distinct advantage that the perturbation due to the electric field of the nucleus is exactly know

Klaus Morawetz, Uwe Fuhrmann, Rainer Walke

The collective motion of a finite nuclear system is investigated by numerical simulation and by linear response theory. Using a pseudo-particle simulation technique we analyze the giant resonances with a multipole decomposition scheme. We examine the energy and the damping of different giant collective modes and obtain the dependence of these quantities on t

F. Hibou, C. Wilkin, A. M. Bergdolt, G. Bergdolt

The total cross section of the p d -> p d eta reaction has been measured at two energies near threshold by detecting the final proton and deuteron in a magneti spectrometer. The values are somewhat larger than expected on the basis of two simple theoretical estimates.

V. B. Taranenko, I. Ganne, R. J. Kuszelewicz, C. O. Weiss

We show experimentally the existence of bright and dark spatial solitons in a passive quantum-well-semiconductor resonator of large Fresnel number. For the wavelength of observation the nonlinearity is mixed absorptive/defocusing. Bright solitons appear more stable than dark ones.

V. B. Taranenko, I. Ganne, R. J. Kuszelewicz, C. O. Weiss

We report experiments on spatial switching dynamics and steady state structures of passive nonlinear semiconductor resonators of large Fresnel number. Extended patterns and switching front dynamics are observed and investigated. Evidence of localization of structures is given.

F. W. Nijhoff, A. J. Walker

We present a general scheme to derive higher-order members of the Painleve VI (PVI) hierarchy of ODE&#39;s as well as their difference analogues. The derivation is based on a discrete structure that sits on the background of the PVI equation and that consists of a system of partial difference equations on a multidimensional lattice. The connection with the i