June 2000 arXiv papers — page 22

Patricio Haeberle, Wladimir Ibanez, Rolando Esparza, Patricio Vargas

We present results from Inverse photoemission spectroscopy in the isochromat mode, with angular resolution, from the clean Au(113) surface. To identify the origin of the different resonances we have performed first principles calculations of the bulk band structure in the LMTO formalism. Using the particular characteristic of the spectrometer we have made a

Steven R. White, D. J. Scalapino

Experiments show evidence for stripe formation in the underdoped cuprates. Here we discuss recent numerical calculations on the t-J model which tell us about the mechanism responsible for stripe formation and the relationship between stripes and superconductivity.

Jan Govaerts, Damien Bertrand, Geoffrey Stenuit

The manifestly Lorentz covariant Landau-Ginzburg equations coupled to Maxwell's equations are considered as a possible framework for the effective description of the interactions between low temperature superconductors and magnetic as well as electric fields. A specific experimental set-up, involving a nanoscopic superconductor and only static applied fi

E. Trizac

We investigate, within a local density functional theory formalism, the interactions between like-charged polyions immersed in a confined electrolyte. We obtain a simple condition for a repulsive effective pair potential, that can be related to the thermodynamic stability criterion of the uncharged counterpart of microscopic species constituting the electrol

Frederic Mila, Fu-Chun Zhang

One dimensional spin 1 systems may have a rich phase diagram including Haldane gap and dimerized phases if the usually very small biquadratic exchange becomes significant. We show that this unlikely condition may be fulfilled in electron systems with quasi-degenerate orbitals. This mechanism may have been experimentally realized in the spin 1 chain LiVGe$_2$

M. Sasvari, J. Kertesz, D. E. Wolf

We investigate the inelastic hard disk gas sheared by two parallel bumpy walls (Couette-flow). In our molecular dynamic simulations we found a sensitivity to the asymmetries of the initial condition of the particle places and velocities and an asymmetric stationary state, where the deviation from (anti)symmetric hydrodynamic fields is stronger as the normal

Fabrizio Lillo, Rosario N. Mantegna

We study the price dynamics of stocks traded in a financial market by considering the statistical properties both of a single time series and of an ensemble of stocks traded simultaneously. We use the $n$ stocks traded in the New York Stock Exchange to form a statistical ensemble of daily stock returns. For each trading day of our database, we study the ense

Enrico Carlon, Henk van Beijeren

A mean field theory is developed for the calculation of the surface free energy of the staggered BCSOS, (or six vertex) model as function of the surface orientation and of temperature. The model approximately describes surfaces of crystals with nearest neighbor attractions and next nearest neighbor repulsions. The mean field free energy is calculated by expr

Mohamed Tij, Andrés Santos

The Bhatnagar-Gross-Krook kinetic model of the Boltzmann equation is solved for the steady cylindrical Poiseuille flow fed by a constant gravity field. The solution is obtained as a perturbation expansion in powers of the field (through fourth order) and for a general class of repulsive potentials. The results, which are hardly sensitive to the interaction p

M. Baake, D. Joseph, P. Kramer, M. Schlottmann

It is shown how root lattices and their reciprocals might serve as the right pool for the construction of quasicrystalline structure models. All non-periodic symmetries observed so far are covered in minimal embedding with maximal symmetry.

Kwan-tai Leung, Zoltan Neda

Fracture in quasi-statically driven systems is studied by means of a discrete spring-block model. Developed from close comparison with desiccation experiments, it describes crack formation induced by friction on a substrate. The model produces cellular, hierarchical patterns of cracks, characterized by a mean fragment size linear in the layer thickness, in a

Ch. Haeussler, J. Oppenlaender, N. Schopohl

A theoretical study on the voltage response function <V> of a series array of dc SQUIDs is presented in which the elementary dc SQUID loops vary in size and, possibly, in orientation. Such series arrays of two-junction SQUIDs possess voltage response functions vs. external magnetic field B that differ substantially from those of corresponding regular series

Lorenzo W. Bernardi, Hajime Yoshino, Koji Hukushima, Hajime Takayama

A new protocol of the zero-field-cooled (ZFC) magnetization process is studied experimentally on an Ising spin-glass (SG) Fe$_{0.50}$Mn$_{0.50}$TiO$_3$ and numerically on the Edwards-Anderson Ising SG model. Although the time scales differ very much between the experiment and the simulation, the behavior of the ZFC magnetization observed in the two systems c

Jianhui Dai, Yupeng Wang

We study the low temperature behavior of a boundary magnetic impurity S&#39;=1/2 in an open ferromagnetic Takhatajian-Babujian spin-S chain. For antiferromagnetic Kondo coupling, it is show via Bethe ansatz solution that the impurity spin is always locked into the critical behavior the bulk. At low temperature, a local composite of spin S-1/2 forms near the

H. Liang, R. W. Hunstead, M. Birkinshaw, P. Andreani

We report the detection of a diffuse radio halo source in the hottest known cluster of galaxies 1E0657-56 (RXJ0658-5557). The radio halo has a morphology similar to the X-ray emission from the hot intracluster medium. The presence of a luminous radio halo in such a hot cluster is further evidence for a steep correlation between the radio halo power and the X

L. A. Anchordoqui, M. T. Dova, T. P. McCauley, T. Paul

We critically review the common belief that ultrahigh energy cosmic rays are protons or atomic nuclei with masses not exceeding that of iron. We find that heavier nuclei are indeed possible, and discuss possible sources and acceleration mechanisms for such primaries. We also show detailed simulations of extensive air showers produced by ``superheavy'' nuclei

A. Vidal-Madjar, D. Kunth, A. Lecavelier des Etangs, J. Lequeux

The metal deficient starburst galaxy IZw18 has been observed with FUSE in a search for H2 molecules. The spectrum obtained with an aperture covering the full galaxy shows no absorption lines of diffuse H2 at the radial velocity of the galaxy. The upper limit for the diffuse H2 column density is found to be very low: N(H2) <~ 10^15 cm-2 (10 sigma), unlike our

F. Zagury

The interpretation of observations over different wavelength domains, which now exist over a large fraction of the sky, will be used to determine relationships between a nebula and its&#39; illuminating source. The illuminating source of a high latitude nebula must be behind the cloud and e.g. at close angular distance. It is either a point source behind the

P. Monaco, G. Efstathiou, S. J. Maddox, E. Branchini

The algorithm ZTRACE of Monaco & Efstathiou (1999) is applied to the IRAS PSCz catalogue to reconstruct the initial conditions of our local Universe with a resolution down to ~5 Mpc/h. The 1-point PDF of the reconstructed initial conditions is consistent with the assumptions that (i) IRAS galaxies trace mass on scales of ~5 Mpc/h, and (ii) the statistics of

E. Massaro, G. Cusumano, M. Litterio, T. Mineo

The Crab Nebula and the Pulsar have been pointed several times by the BeppoSAX satellite. We analysed all these observations, summed together, to study the main spectral properties with a good phase resolution. A new accurate estimate of the hydrogen column density in the Crab direction N_H=3.23 x 10^(21) cm^(-2) is given as derived from the analysis of the

M. Wold, M. Lacy, P. B. Lilje, S. Serjeant

Over the past few years, we have been collecting data with the Nordic Optical Telescope (NOT) on the galaxy environments around active galactic nuclei (AGN). Here we present some results from a sample of 21 radio-loud and 20 radio-quiet quasars in the redshift range 0.5 < z < 0.8. We find a few quasars in very rich environments, perhaps as rich as Abell clas

Adi Nusser, Luiz N. da Costa, Enzo Branchini, Mariangela Bernardi

We present a comparison between the peculiar velocity field measured from the ENEAR all-sky $D_n-σ$ catalog and that derived from the galaxy distribution of the IRAS PSCz redshift survey. The analysis is based on a modal expansion of these data in redshift space by means of spherical harmonics and Bessel functions. The effective smoothing scale of the expans

S. G. H. Berendsen, R. Fender, E. Kuulkers, J. Heise

We have performed simultaneous X-ray and radio observations of thirteen Galactic centre low-mass X-ray binaries in 1998 April using the Wide-Field Cameras onboard BeppoSAX and the Australia Telescope Compact Array, the latter simultaneously at 4.8 and 8.64 GHz. We detect two Z sources, GX 17+2 and GX 5-1, and the unusual `hybrid&#39; source GX 13+1. Upper li

Jochen M. Braun, Klaas S. de Boer, Martin Altmann

The huge supergiant shell (SGS) LMC4, next to the giant HII region 30 Doradus the second most impressive feature of the Large Magellanic Cloud (LMC), has been the subject of many studies and was used to test various models of star forming mechanisms. In this paper we present a B, V photometry of the very centre of this SGS. The new data yield an age of 11(2)

J. Bland-Hawthorn

While tunable filters are a recent development in night time astronomy, they have long been used in other physical sciences, e.g. solar physics, remote sensing and underwater communications. With their ability to tune precisely to a given wavelength using a bandpass optimized for the experiment, tunable filters are already producing some of the deepest narro

J. Bland-Hawthorn, R. J. Reynolds

The interstellar medium (ISM) can be thought of as the galactic atmosphere which fills the space between stars. When clouds within the ISM collapse, stars are born. When the stars die, they return their matter to the surrounding gas. Therefore the ISM plays a vital role in galactic evolution. The medium includes starlight, gas, dust, planets, comets, asteroi

W. J. G. de Blok, F. Walter

We present a wide-field, high spatial and velocity resolution map of the entire extended HI distribution of the nearby Local Group dwarf galaxy NGC 6822. The observations were obtained with the Parkes single-dish telescope and the Australia Telescope Compact Array in mosaicing mode. NGC 6822 has an extended HI-disk which is shaped by the presence of numerous

Maurice H. P. M. van Putten, Abhinanda Sarkar

Coalescence of low mass compact binaries of neutron stars and black holes are primary burst sources for LIGO and VIRGO.Of importance in the early stages of observations will be the classification of candidate detections by source-type. The diversity in source parameters and serendipity in any new window of observations suggest to consider model-independent d

Y. Terashima, L. C. Ho, A. F. Ptak, T. Yaqoob

We present results of new ASCA observations of the low-luminosity AGN (LLAGN) NGC 4579 obtained on 1998 December 18 and 28, and we report on detection of variability of an iron K emission line. The X-ray luminosities in the 2--10 keV band for the two observations are nearly identical (LX $\approx$ 2$\times10^{41}$ ergs/s), but they are $\sim$35% larger than

Andreas Schweitzer, Peter H. Hauschildt, E. Baron

We present a technique to treat systems with very many levels, like molecules, in non-LTE. This method is based on a superlevel formalism coupled with rate operator splitting. Superlevels consist of many individual levels that are assumed to be in LTE relative to each other. The usage of superlevels reduces the dimensionality of the rate equations dramatical

G. Tautvaisiene, B. Edvardsson, I. Tuominen, I. Ilyin

High-resolution spectra of six core helium-burning `clump&#39; stars and three giants in the open cluster M 67 have been obtained with the SOFIN spectrograph on the Nordic Optical Telescope to investigate abundances of up to 25 chemical elements. Abundances of carbon were studied using the C2 Swan (0,1) band head at 5635.5 A. The wavelength interval 7980-813

Laura Ferrarese, David Merritt

The masses of supermassive black holes correlate almost perfectly with the velocity dispersions of their host bulges, M(BH) ~ sigma^alpha, where alpha =4.8 +/- 0.5$. The relation is much tighter than the relation between M(BH) and bulge luminosity, with a scatter no larger than expected on the basis of measurement error alone. Black hole masses estimated by

Pascal Chauve, Pierre Le Doussal, Kay Wiese

We study the field theories for pinned elastic systems at equilibrium and at depinning. Their $β$-functions differ to two loops by novel ``anomalous&#39;&#39; terms. At equilibrium we find a roughness $ζ=0.20829804 ε+ 0.006858 ε^2$ (random bond), $ζ=ε/3$ (random field). At depinning we prove two-loop renormalizability and that random field attracts shorter r

Adam Ritz, Mikhail Shifman, Arkady Vainshtein, Mikhail Voloshin

We discuss the restructuring of the BPS spectrum which occurs on certain submanifolds of the moduli/parameter space -- the curves of the marginal stability (CMS) -- using quasiclassical methods. We argue that in general a `composite&#39; BPS soliton swells in coordinate space as one approaches the CMS and that, as a bound state of two `primary&#39; solitons,

Kiyoshi Higashijima, Muneto Nitta

The Riemann normal coordinate expansion method is generalized to a Kahler manifold. The Kahler potential and holomorphic coordinate transformations are used to define a normal coordinate preserving the complex structure. The existence of this Kahler normal coordinate is shown explicitly to all orders. The formalism is applied to background field methods in s

Teruyuki Kitabayashi, Masaki Yasue

By using the $L_e$ - $L_μ$ - $L_τ$ symmetry, we construct an $SU(3)_L\times U(1)_N$ gauge model that provides two-loop radiative neutrino masses as well as one-loop radiative neutrino masses. The generic smallness of two-loop neutrino masses leading to $Δm^2_\odot$ compared with one-loop neutrino masses leading to $Δm^2_{atm}$ successfully explains $Δm^2_{at

Heon-Young Chang, Insu Yi

We study the power density spectrum (PDS) of artificial light curves of observed gamma-ray bursts (GRBs). We investigate statistical properties of GRB light curves by comparing the reported characteristics in the PDSs of the observed GRBs with those that we model, and discuss implications on interpretations of the PDS analysis results. Results of PDS analysi

Andrei Khrennikov

We present comparative probabilistic analysis of the Greenburger-Horne-Zeilinger paradox in the frameworks of Kolmogorov&#39;s (measure-theoretical) and von Mises&#39; (frequency) models of the probability theory. This analysis demonstrated that the GHZ paradox is merely a consequence of the use of Kolmogorov&#39;s probabilistic model. By using von Mises&#39

Ilya Zakharevich

Veronese webs are rich geometric structures with deep relationships to various domains of mathematics. The PDEs which determine the Veronese web are overdetermined if dim >3, but in the case dim =3 they reduce to a special flavor of a non-linear wave equation. The symmetries embedded in the definition of a Veronese web reveal themselves as Bäcklund--Darboux

Lucian M. Ionescu

The &#34;quantum-event / prime ideal in a category/ noncommutative-point&#34; alternative to &#34;classical-event / commutative prime ideal/ point&#34; is suggested. Ideals in additive categories, prime spectra and representation of quivers are considered as mathematical tools appropriate to model quantum mechanics. The space-time framework is to be reconstr

Izu Vaisman

In this note we give conditions which ensure the reduction of a symplectic connection in the process of a Marsden-Weinstein reduction and of the reduction of a presymplectic manifold.

D. Binosi, M. Shifman, T. ter Veldhuis

We discuss quantum tunneling between classically BPS saturated solitons in two-dimensional theories with N=2 supersymmetry and a compact space dimension. Genuine BPS states form shortened multiplets of dimension two. In the models we consider there are two degenerate shortened multiplets at the classical level, but there is no obstruction to pairing up throu

Kiyoshi Higashijima, Muneto Nitta

Supersymmetric nonlinear sigma models are formulated as gauge theories. Auxiliary chiral superfields are introduced to impose supersymmetric constraints of F-type. Target manifolds defined by F-type constraints are always non-compact. In order to obtain nonlinear sigma models on compact manifolds, we have to introduce gauge symmetry to eliminate the degrees

B. S. Zou

Vector charmonium states $J/Ψ$ and $Ψ&#39;$ are copiously produced by $e^+e^-$ annihilations at the Beijing Electron Positron Collider (BEPC). Their decays provide an excellent place for studying excited nucleons and hyperons -- $N^*$, $Λ^*$, $Σ^*$ and $Ξ^*$ resonances. The systematic study of these excited nucleons and hyperons can provide us with critical

L. C. Garcia de Andrade

The thermodynamics is extented to spacetimes with spin-torsion density.Impplications to Einstein-Cartan-de Sitter inflationary phases are discussed.A relation between the spin-torsion density,entropy and temperature is presented.A lower limit for the radius of the Universe may be obtained from the spin-torsion density and the Planck lenght.

Pascal Chauve, Pierre Le Doussal

We develop a systematic multi-local expansion of the Polchinski-Wilson exact renormalization group (ERG) equation. Integrating out explicitly the non local interactions, we reduce the ERG equation obeyed by the full interaction functional to a flow equation for a function, its local part. This is done perturbatively around fixed points, but exactly to any gi

Nikolay Prokof&#39;ev, Philip Stamp

We consider a SQUID tunneling between 2 nearly degenerate flux states. Decoherence caused by paramagnetic and nuclear spins in the low-$T$ limit is shown to be much stronger than that from electronic excitations. The decoherence time $τ_ϕ$ is determined by the linewidth $E_o$ of spin bath states, which can be reduced by a correct choice of ring geometry and

Sumiyoshi Abe

It is pointed out that the Tsallis entropy functional represented in terms of the escort distribution is not concave of the entropic index $q$ is less than unity. It is emphasized that the escort distribution is a secondary object calculated from the basic original distribution.

Markus Porto, Michael Urbakh, Joseph Klafter

We introduce a new approach to build microscopic engines on the atomic scale that move translationally or rotationally and can perform useful functions such as pulling of a cargo. Characteristic of these engines is the possibility to determine dynamically the directionality of the motion. The approach is based on the transformation of the fed energy to direc

Markus Porto, Michael Urbakh, Joseph Klafter

We investigate the dynamics of a classical particle in a one-dimensional two-wave potential composed of two periodic potentials, that are time-independent and of the same amplitude and periodicity. One of the periodic potentials is externally driven and performs a translational motion with respect to the other. It is shown that if one of the potentials is of

Stefan Scheidl, Yusuf Dincer

We employ a functional renormalization group to study interfaces in the presence of a pinning potential in $d=4-ε$ dimensions. In contrast to a previous approach [D.S. Fisher, Phys. Rev. Lett. {\bf 56}, 1964 (1986)] we use a soft-cutoff scheme. With the method developed here we confirm the value of the roughness exponent $ζ\approx 0.2083 ε$ in order $ε$. Goi

Lars Melwyn Jensen, Beom Jun Kim, Petter Minnhagen

The dynamic critical exponent $z$ is determined numerically for the $d$-dimensional XY model ($d=2, 3$, and 4) subject to relaxational dynamics and resistively shunted junction dynamics. We investigate both the equilibrium fluctuation and the relaxation behavior from nonequilibrium towards equilibrium, using the finite-size scaling method. The resulting valu

Hisamitsu Awaki, Shiro Ueno, Yoshiaki Taniguchi, Kimberly A. Weaver

We analyze the 0.5-10 keV spectra of six Seyfert 2 galaxies observed with the X-ray satellite ASCA: Mrk 3, Mrk 348, Mrk 1210, Mrk 477, NGC 7212, and Was 49b. These galaxies were selected based on their possession of optical polarized broad lines. In the 2-10 keV band, their spectra are heavily absorbed, with 2-10 keV absorption-corrected X-ray luminosities r

S. Prunet, C. B. Netterfield, E. Hivon, B. P. Crill

We describe here an iterative method for jointly estimating the noise power spectrum from a scanning experiment&#39;s time-ordered data, together with the maximum-likelihood map. We test the robustness of this method on simulated datasets with colored noise, like those of bolometer receivers in CMB experiments.

S. N. Fabrika, G. G. Valyavin, T. E. Burlakova, E. A. Barsukova

This paper describes results of magnetic field measurements of white dwarfs carried out on the 6-m telescope for the last years. A magnetic field of about Be ~ 28 kG has been discovered in the degenerate star WD 1953-011. A rotational period of WD 0009+501, 1.83 hours, has been discovered, the average magnetic field of the star is <Be> = -42.3 +/- 5.4 kG and

A. C. Doherty, T. W. Lynn, C. J. Hood, H. J. Kimble

Two recent experiments have reported the trapping of individual atoms inside optical resonators by the mechanical forces associated with single photons [Hood et al., Science 287, 1447 (2000) and Pinkse et al., Nature 404, 365 (2000)]. Here we analyze the trapping dynamics in these settings, focusing on two points of interest. Firstly, we investigate the exte

Kirill A. Bronnikov

It is shown that general relativity coupled to nonlinear electrodynamics (NED) with the Lagrangian $L(F)$, $F = F_mn F^mn$ having a correct weak field limit, leads to nontrivial static, spherically symmetric solutions with a globally regular metric if and only if the electric charge is zero and $L(F)$ tends to a finite limit as $F \to \infty$. Properties and

Guillaume Adenier

Bell&#39;s Theorem was developed on the basis of considerations involving a linear combination of spin correlation functions, each of which has a distinct pair of arguments. The simultaneous presence of these different pairs of arguments in the same equation can be understood in two radically different ways: either as `strongly objective,&#39; that is, all c

K. Sengupta, Hyok-Jon Kwon, Victor M. Yakovenko

We develop a microscopic picture of the electron states localized at the edges perpendicular to the chains in the Bechgaard salts in the quantum Hall regime. In a magnetic-field-induced spin-density-wave state (FISDW) characterized by an integer N, there exist N branches of chiral gapless edge excitations. Localization length is much longer and velocity much

Andrea Brignole, Anna Rossi

We point out that the interactions of goldstinos with matter supermultiplets are a potential source of flavour violation, if fermion and sfermion mass matrices are not aligned and supersymmetry is spontaneously broken at a low scale. We study the impact of those couplings on low-energy processes such as μ\to e γ, μ\to eee, K \to μ^+ μ^-, K-\ov{K} transitions

Tomasz Kobak, Michal Ostrowski

The role of MHD turbulence in the cosmic ray acceleration process in a volume with a reconnecting magnetic field is studied by means of Monte Carlo simulations. We performed modelling of proton acceleration with the 3D analytic model of stationary reconnection of Craig et al. (1995) providing the unperturbed background conditions. Perturbations of particle t

Troels Harmark

We study the non-critical space-time non-commutative open string (NCOS) theory using a dual supergravity description in terms of a certain near-horizon limit of the F1-Dp bound state. We find the thermodynamics of NCOS theory from supergravity. The thermodynamics is equivalent to Yang-Mills theory on a commutative space-time. We argue that this fact does not

Andrew C. Doherty, Kurt Jacobs, Gerard Jungman

We consider separating the problem of designing Hamiltonian quantum feedback control algorithms into a measurement (estimation) strategy and a feedback (control) strategy, and consider optimizing desirable properties of each under the minimal constraint that the available strength of both is limited. This motivates concepts of information extraction and dist

Vladimir Kostov

Consider the Deligne-Simpson problem: {\em give necessary and sufficient conditions for the choice of the conjugacy classes $C_j\subset GL(n,{\bf C})$ (resp. $c_j\subset gl(n,{\bf C})$) so that there exist irreducible $(p+1)$-tuples of matrices $M_j\in C_j$ (resp. $A_j\in c_j$) satisfying the equality $M_1... M_{p+1}=I$ (resp. $A_1+... +A_{p+1}=0$)}. The mat

Louis H. Kauffman, David E. Radford

In GT/0006019 oriented quantum algebras were motivated and introduced in a natural categorical setting. Invariants of knots and links can be computed from oriented quantum algebras, and this includes the Reshetikhin-Turaev theory for Ribbon Hopf algebras. Here we continue the study of oriented quantum algebras from a more algebraic perspective, and develop a

Louis H. Kauffman, David E. Radford

This paper defines the concept of an oriented quantum algebra and develops its application to the construction of quantum link invariants. We show that all known quantum link invariants can be put into this framework.

Kazuo Ghoroku

This paper has been withdrawn by the author due to a misunderstanding.

M. Chaichian, M. Gogberashvili, A. B. Kobakhidze

We argue that a certain distribution of matter in higher dimensions can provide the correct behaviour of gravity in four dimensions. Some explicit examples illustrating the idea are considered.

Hsien-Hung Shih, Shih-Chang Lee, Hsiang-nan Li

We study the polarized $Λ_b$ baryon semileptonic decay $Λ_b \to Λ_cl{\barν}$ using perturbative QCD factorization theorem. In this approach heavy baryon transition form factors are expressed as the convolutions of hard $b$ quark decay amplitudes with universal $Λ_b$ and $Λ_c$ baryon wave functions. With the heavy baryon wave functions determined in our previ

Andrew Akeroyd, Abdesslam Arhrib, El--Mokhtar Naimi

Tree-level unitarity constraints on the masses of the Higgs bosons in the general Two Higgs Doublet Model (THDM) are studied. We first consider the case where the Higgs potential is invariant under a discrete symmetry transformation, and derive strong constraints on the mass of the lightest CP-even Higgs boson ($M_h$) as a function of $\tanβ$. We then show t

Nuno Barros e Sa

Starting from a Lagrangian we perform the full constraint analysis of the Hamiltonian for General relativity in the tetrad-connection formulation for an arbitrary value of the Immirzi parameter and solve the second class constraints, presenting the theory with a Hamiltonian composed of first class constraints which are the generators of the gauge symmetries

Mario Castagnino, Roberto Laura

Decoherence and the approach to the classical final limit are studied in two similar cases: the Mott and the Cosmological problems.

Roberto Aquilano, Mario Castagnino, Ernesto Eiroa

In this paper we improve the results of sec. VI of paper [M. Castagnino, Phys. Rev. D 57, 750 (1998)] by considering that the main source of entropy production are the photospheres of the stars.

Roberto Aquilano, Mario Castagnino, Ernesto Eiroa

In this letter the paper [R. Aquilano, M. Castagnino, Mod. Phys. Lett A,11, 755 (1996)] is improved by considering that the main source of entropy production are the stars photospheres.

Mario Castagnino

The functional method, introduced to deal with systems endowed with a continuous spectrum, is used to study the problem of decoherence and correlations in a simple cosmological model.

Wataru Souma

The exact renormalization group equation for pure quantum gravity is derived for an arbitrary gauge parameter in the space-time dimension $d=4$. This equation is given by a non-linear functional differential equation for the effective average action. An action functional of the effective average action is approximated by the same functional space of the Eins

Walter Kob, Leticia F. Cugliandolo

We use computer simulations to study the (driven) dynamics of a charged polymer in a disordered medium, thus mimicking the setting used in gel electrophoresis. In agreement with experiments, we find that inside the gel the mobility of the polymer is only a weak function of its length N. In contrast to this, the mean entrance time into the gel, is a very stro

R. A. Broglia, G. Tiana

While all the information required for the folding of a protein is contained in its amino acid sequence, one has not yet learnt how to extract this information so as to predict the detailed, biological active, three-dimensional structure of a protein whose sequence is known. This situation is not particularly satisfactory, in keeping with the fact that while

Carl H. Gibson, Rudolph E. Schild

Nonlinear gravitational condensation theory and quasar-microlensing observations lead to the conclusion that the baryonic mass of most galaxies is dominated by dense clumps of hydrogenous planetoids. Star microlensing collaborations fail to detect planetoids as the dominant dark matter component of the Galaxy halo by an unjustified uniform-number-density ass

Valentin D. Ivanov, Mario Hamuy, Philip A. Pinto

We study the properties of Type Ia Supernovae (SNe Ia) as functions of the radial distance from their host galaxy centers. Using a sample of 62 SNe Ia with reliable luminosity, reddening, and decline rate determinations, we find no significant radial gradients of SNe Ia peak absolute magnitudes or decline rates in elliptical+S0 galaxies, suggesting that the

Kim A. Venn, J. K. McCarthy, D. J. Lennon, N. Przybilla

The first stellar abundances in M31 are presented, based on Keck I HIRES spectroscopy and model atmospheres analyses of three A-F supergiants, 41-2368, 41-3712, and A-207. We also present the preliminary analysis of a fourth star, 41-3654. We find that the stellar oxygen abundances are in good agreement with those determined from nebular studies, even though

Abhay Ashtekar, Christopher Beetle, Olaf Dreyer, Stephen Fairhurst

Boundary conditions defining a generic isolated horizon are introduced. They generalize the notion available in the existing literature by allowing the horizon to have distortion and angular momentum. Space-times containing a black hole, itself in equilibrium but possibly surrounded by radiation, satisfy these conditions. In spite of this generality, the con

Thomas Schaefer

We study QCD with one flavor at finite baryon density. In the limit of very high baryon density the system is expected to be a color superconductor. In the case of one flavor, the order parameter is in a $\bar 3$ of color and has total angular momentum one. We show that in weak coupling perturbation theory, the energetically preferred phase exhibits ``color-

Nick E. Mavromatos, Elizabeth Winstanley

We discuss the properties of matter in a D-dimensional anti-de-Sitter-type space time induced dynamically by the recoil of a very heavy D(irichlet)-particle defect embedded in it. The particular form of the recoil geometry, which from a world-sheet view point follows from logarithmic conformal field theory deformations of the pertinent sigma-models, results

S. R. Elliott

Neutrino interactions with lead produce neutrons in numbers that depend on neutrino energy and type. A detector based on lead perchlorate, for example, would be able to measure the energy deposited by electrons and gammas in coincidence with the number of neutrons produced. Sorting the electron energy spectra by the number of coincident neutrons permits the

J. Gamboa, F. Mendez

An approach to scattering theory in three dimensional AdS spaces is proposed. Firstly we consider the scattering of spinless relativistic particles by a three dimensional extremal black hole and compute the absorption cross section $σ_{abs} =J_{abs}/J_{\infty}$ without using {\it in} and {\it out} states. Secondly, we posit a reciprocal space ${\cal H}$ wher

David Atwood, Shaouly Bar-Shalom, Gad Eilam, Amarjit Soni

CP violation in top physics is reviewed. The Standard Model has negligible effects, consequently CP violation searches involving the top quark may constitute the best way to look for physics beyond the Standard Model. Non-standard sources of CP violation due to an extended Higgs sector with and without natural flavor conservation and supersymmetric theories

A. Crisanti, F. Ritort, A. Rocco, M. Sellitto

e discuss the relevance of the Stillinger and Weber approach to the glass transition investigating the non-equilibrium behavior of models with non-trivial dynamics, but with simple equilibrium properties. We consider a family of 1D constrained kinetic models, which interpolates between the asymmetric chain introduced by Eisinger and Jäckle [Z. Phys. {\bf B84

J. P. Alexander, CLEO Collaboration

We analyze 9.7 x 10^6 B\bar{B}$ pairs recorded with the CLEO detector to determine the production ratio of charged to neutral B-meson pairs produced at the Y(4S) resonance. We measure the rates for B^0 -> J/psi K^{(*)0} and B^+ -> J/psi K^{(*)+} decays and use the world-average B-meson lifetime ratio to extract the relative widths f+-/f00 = Gamma(Y(4S) -> B+

M. V. Garzelli, C. Giunti

We propose a modification to the standard statistical treatment of the detection cross-section uncertainties in the analysis of solar neutrino data. We argue that the uncertainties of the energy-averaged cross sections of the different neutrino fluxes in the same experiment should be treated as correlated. We show that the resulting allowed regions for the n

Pierre Cizeau, Marc Potters, Jean-Philippe Bouchaud

It is commonly believed that the correlations between stock returns increase in high volatility periods. We investigate how much of these correlations can be explained within a simple non-Gaussian one-factor description with time independent correlations. Using surrogate data with the true market return as the dominant factor, we show that most of these corr

Sushan Konar

The evolution of the magnetic field in an accreting neutron star is investigated using a fully general relativistic treatment and assuming that initially the currents supporting the field are completely confined to the crust. We find that the field decay slows down due to the inclusion of the curvature of space-time but the final results do not differ signif

Salah Hamieh, Krzysztof Redlich, Ahmed Tounsi

We consider the production of strange particles in Pb-Pb and p-A collisions at the SPS energy reported by the WA97 experiment. We show that the observed enhancement of strange baryon and antibaryon yields in Pb-Pb collisions relative to p-Be and p-Pb can be explained in terms of the statistical model formulated in canonical ensemble with respect to strangene

Jun-Ichi Sumi

In this paper, we investigate the beta-function of the gauge coupling constant ($e$) of the gauged four-fermi theory in the Exact Renormalization Group (ERG) framework. It seems that the presence of the four-fermi interaction strongly affects to the naive RG running of the gauge coupling constant. We show that this strong correction has no physical meaning s

E. Ivanov, S. Krivonos, O. Lechtenfeld

We elaborate on a new N=2, d=3 supermultiplet (double-vector multiplet) with a non-trivial off-shell realization of the central charge. Its bosonic sector comprises two abelian gauge vector fields forming an SO(2) vector. We present a superfield formulation of this multiplet in the central-charge extended N=2, d=3 superspace and then employ it, in the framew

Taizo Muta, Akio Sugamoto, Mao-Zhi Yang, Ya-Dong Yang

Motivated by recent measurements, we investigate $B\to ππ, K π$ decay modes in the framework of QCD improved factorization, which was recently proposed by Beneke $et al$. We find that all the measured branching ratios are well accommodated in the reasonable parameter space except for $B\to K^0 π^0 $. We also discuss in detail the strong penguin contributions

V. G. Benza

Nonhermitean hamiltonians of convection-diffusion type occur in the description of vortex motion in the presence of a tilted magnetic field as well as in models of driven population dynamics. We study such hamiltonians in the case of rectangular barriers of variable size. We determine Lyapunov exponent and wavenumber of the eigenfunctions within an adiabatic

I. R. Afnan, F. Bissey, J. Gomez, A. T. Katramatou

We investigate deep inelastic scattering from He-3 and H-3 within a conventional convolution treatment of binding and Fermi motion effects. Using realistic Faddeev wave functions together with a nucleon spectral function, we demonstrate that the free neutron structure function can be extracted in deep-inelastic scattering from A=3 mirror nuclei, with nuclear

T. T. Takahashi, H. Matsufuru, Y. Nemoto, H. Suganuma

The static three-quark (3Q) potential is measured in the SU(3) lattice QCD with $12^3 \times 24$ and $β=5.7$ at the quenched level. From the 3Q Wilson loop, the 3Q ground-state potential $V_{\rm 3Q}$ is extracted using the smearing technique for the ground-state enhancement. With accuracy better than a few %, $V_{\rm 3Q}$ is well described by a sum of a cons

B. Roy Frieden, A. Plastino

Consider any stationary Schroedinger wave equation (SWE) solution $psi (x)$ for a particle. The corresponding PDF on position QTR{em}{x} of the particle is QTR{em}{p}$_{X}(x)=|psi (x)|^{2}$. There is a classical trajectory QTR{em}{x(t)} for the particle that is consistent with this PDF. The trajectory is unique to within an additive constant corresponding to