July 2002 arXiv papers — page 4

S. Ferrara, M. Porrati

We argue that extremal black holes of N=4 Poincare supergravity coupled to conformal matter have a quantum-exact dual 5-d description in the maximally supersymmetric extension of the Randall-Sundrum theory. This dual is a the classical, static supergravity solution describing a string with both Neveu-Schwarz and Ramond charge with respect to different antisy

Erich J. Mueller

We present a theory of hysteretic phenomena in Bose gases, using superfluidity in one dimensional rings and in optical lattices as primary examples. Through this study we are able to give a physical interpretation of swallowtail loops recently found by many authors in the mean-field energy structure of trapped atomic gases. These loops are a generic sign of

Franco Bagnoli, Fabio Cecconi, Alessandro Flammini, Alessandro Vespignani

We study the asymptotic behaviour of the Bak, Tang, Wiesenfeld sandpile automata as a closed system with fixed energy. We explore the full range of energies characterizing the active phase. The model exhibits strong non-ergodic features by settling into limit-cycles whose period depends on the energy and initial conditions. The asymptotic activity $ρ_a$ (top

Wim H. Hesselink

Simulations of specifications are introduced as a unification and generalization of refinement mappings, history variables, forward simulations, prophecy variables, and backward simulations. A specification implements another specification if and only if there is a simulation from the first one to the second one that satisfies a certain condition. By adding

Y. Machida, S. Sasaki, H. Fujii, M. Furuyama

We synthesized single crystalline and policrystalline MgB_2 under ambient pressures. The single crystals of MgB_2 were of good quality, where the crystal structure refinements were successfully converged with R = 0.020. The specific heat of policrystalline MgB_2 samples has been measured in a temperature range between 2 and 60 K in magnetic field up to 6 T.

M. N. Chernodub, E. -M. Ilgenfritz, A. Schiller

We study the breaking of the string spanned between test charges in the three dimensional Abelian Higgs model with compact gauge field and fundamentally charged Higgs field at zero temperature. In agreement with current expectations we demonstrate that string breaking is associated with pairing of monopoles. However, the string breaking is not accompanied by

Alex Kaivarainen

The short version of new quantum quantitative Hierarchic theory, general for solids and liquids is presented. Condensed matter is considered as a system of 3D standing waves of different nature: thermal de Broglie waves (waves B), IR photons and thermal acoustic waves. Theory is verified by computer simulations on examples of pure water and ice, using specia

Gregory Freiman, Boris Granovsky

We develop a unified approach to the problem of clustering in the three different fields of applications, as indicated in the title the paper. The approach is based on Khintchine's probabilistic method that grew out of the Darwin-Fawler method in statistical physics. Our main result is the derivation of asymptotic formulae for probabilities of clusters (

Y. F. Huang, T. Lu, Z. G. Dai, K. S. Cheng

Based on a refined generic dynamical model, we investigate afterglows from jetted gamma-ray burst (GRB) remnants numerically. In the relativistic phase, the light curve break could marginally be seen. However, an obvious break does exist at the transition from the relativistic phase to the non-relativistic phase, which typically occurs at time 10 to 30 days.

Maxim Raginsky

We study information storage in noisy quantum registers and computers using the methods of statistical dynamics. We develop the concept of a strictly contractive quantum channel in order to construct mathematical models of physically realizable, i.e., nonideal, quantum registers and computers. Strictly contractive channels are simple enough, yet exhibit very

Luc Bouten, Hans Maassen, Burkhard Kuemmerer

Starting point is a given semigroup of completely positive maps on the 2 times 2 matrices. This semigroup describes the irreversible evolution of a decaying 2-level atom. Using the integral-sum kernel approach to quantum stochastic calculus we couple the 2-level atom to an environment, which in our case will be interpreted as the electromagnetic field. The i

G. Scolarici, L. Solombrino

A necessary and sufficient condition in order that a (diagonalizable) pseudohermitian operator admits an antilinear symmetry T such that T^{2}=-1 is proven. This result can be used as a quick test on the T-invariance properties of pseudohermitian Hamiltonians, and such test is indeed applied, as an example, to the Mashhoon-Papini Hamiltonian.

Hirotada Kobayashi

This paper introduces quantum analogues of non-interactive perfect and statistical zero-knowledge proof systems. Similar to the classical cases, it is shown that sharing randomness or entanglement is necessary for non-trivial protocols of non-interactive quantum perfect and statistical zero-knowledge. It is also shown that, with sharing EPR pairs a priori, t

M. R. Isherwood, T. S. Monteiro

Using a new type of chaotic ratchet generated by pulsed standing waves of light, we propose a mechanism which would allow packets of atoms travelling through a pulsed optical lattice in one direction to pass almost undisturbed, while strongly heating atoms drifting through in the opposite direction. An analytical formula for the diffusive energy growth is de

A. K. Chaudhuri

We have studied the J/psi suppression in 158 GeV/c Pb+Pb collisions at CERN SPS. J/psi production is assumed to be a two step process, (i) formation of c bar{c} pair, which is accurately calculable in QCD and (ii) formation of J/psi meson from the c bar{c} pair, which can be conveniently parameterized. In a pA/AA collision, as the c bar{c} pair pass through

E. M. F. Curado, M. A. Rego-Monteiro

We present a generalization of the sl(2) algebra where the algebraic relations are constructed with the help of a general function of one of the generators. When this function is linear this algebra is a deformed sl(2) algebra. In the non-linear case, the finite dimensional representations are constructed in two different ways. In the first case, which provi

Andrea Posilicano, Stefania Ugolini

We show how the scattering-into-cones and flux-across-surfaces theorems in Quantum Mechanics have very intuitive pathwise probabilistic versions based on some results by Carlen about large time behaviour of paths of Nelson diffusions. The quantum mechanical results can be then recovered by taking expectations in our pathwise statements.

Gert-Jan van der Heiden

Let K be a function field and let (f) be a principal prime ideal of the ring A, which is a subring of K. Let phi: A --> K {tau} be a Drinfeld module. In this paper we consider the problem whether a point P in K which is a phi(f)-fold locally at each place v of K, i.e., for each v there is a Q in K_v such that phi(f).P = Q, is also a phi(f)-fold globally. We

William Arveson

These lectures concern basic aspects of the theory of semigroups of endomorphisms of type $I$ factors that relate to causal dynamics, dilation theory, and the problem of classifying $E_0$-semigroups up to cocycle conjugacy. We give only a few proofs here; full details can be found in the author's upcoming monograph {\em Noncommutative Dynamics and $E$-se

Meirav Amram, Mina Teicher

This paper is the second in a series of three papers concerning the surface T times T, where T is a complex torus. We compute the fundamental group of the branch curve of the surface in C^2, using the van Kampen Theorem and the braid monodromy factorization of the curve.

Stefaan Vaes, Leonid Vainerman

Continuing our research on extensions of locally compact quantum groups, we give a classification of all cocycle matched pairs of Lie algebras in small dimensions and prove that all of them can be exponentiated to cocycle matched pairs of Lie groups. Hence, all of them give rise to locally compact quantum groups by the cocycle bicrossed product construction.

Sergey Kudryavtsev

Log Enriques surfaces with delta=1 are classified.

Sergey Kudryavtsev

The exceptional log Del Pezzo surfaces with delta=1 are classified.

Vladimir Turaev

We establish a new homological lower bound for the Thurston norm on 1-cohomology of 3-manifolds. This generalizes previous results of C. McMullen, S. Harvey, and the author. We also establish an analogous lower bound for 1-cohomology of 2-dimensional CW-complexes.

Junjiro Noguchi, Joerg Winkelmann

We prove a product decomposition of the Zariski closure of the jet lifts of a holomorphic map f from C into a semi-abelian variety A, provided that f is of finite order. On the other hand, by giving an example of such a map f into a three dimensional abelian variety we show that this product decomposition does not hold in general; there was a gap in the proo

Alexander Polishchuk

We show that Fay's trisecant identity follows from the A_{infinity}-constraint between certain triple Massey products in the derived category of coherent sheaves on a curve. We also deduce the matrix analogue of this identity that can be conveniently formulated using quasideterminants of matrices with non-commuting entries. On the other hand, looking at

S. Khlebnikov

We present numerical evidence that a domain wall in a background with varying vacuum energy density acquires velocity in the direction of decreasing Hubble parameter. This should lead to at least a partial relaxation of the cosmological constant on the wall.

Mustapha Mekhfi

By studying cohomological quantum mechanics on the punctured plane,we were led to identify (reduced) Bessel functions with homotopic loops living on the plane.This identification led us to correspondence rules between exponentials and Bessel functions.The use of these rules makes us retrieve known but also new formulas in Bessel functions theory.

Ning Wu

The quantum gravity is formulated based on gauge principle. The model discussed in this paper has local gravitational gauge symmetry and gravitational field is represented by gauge potential. A preliminary study on gravitational gauge group is presented. Path integral quantization of the theory is discussed in the paper. A strict proof on the renormalizabili

S. Iyer Dutta, M. H. Reno, I. Sarcevic

The energy dependence of "secondary" neutrinos from the process nutau->tau->numubar->mubar for two input tau neutrino fluxes (F^0_nu ~ 1/E_nu and 1/E_nu^2), assumed to have been produced via neutrino oscillations from extragalactic sources, is evaluated to assess the impact of secondary neutrinos on the upward muon rates in a km^3 detector. We show t

E. Kh. Akhmedov

I review some theoretical aspects of neutrino oscillations in the case when more than two neutrino flavours are involved. These include: approximate analytic solutions for 3-flavour (3f) oscillations in matter; matter effects in nu_mu - nu_tau oscillations; 3f effects in oscillations of solar, atmospheric, reactor and supernova neutrinos and in accelerator l

Ralf Hofmann

A generalization of the operator product expansion for Euclidean correlators of gauge invariant QCD currents is presented. Each contribution to the modified expansion, which is based on a delocalized multipole expansion of a perturbatively determined coefficient function, sums up an infinite series of local operators. On a more formal level the delocalized o

Masaaki Fujii, T. Yanagida

We discuss two cosmological issues in a generic gauge-mediated supersymmetry (SUSY)-breaking model, namely the Universe's baryon asymmetry and the gravitino dark-matter density. We show that both problems can be simultaneously solved if there exist extra matter multiplets of a SUSY-invariant mass of the order of the ``$μ$-term'', as suggested in

P. Schweitzer, S. Boffi, M. Radici

Mellin moments of off-forward distribution functions are, at t = 0, even polynomials of the skewedness parameter xi. It is proven that the unpolarized off-forward distribution functions in the chiral quark soliton model satisfy this so called polynomiality property. The proof is an important contribution to the demonstration that the description of off-forwa

M. Hirsch, W. Porod, J. C. Romao, J. W. F. Valle

Supersymmetry with bilinear R-parity violation provides a predictive framework for neutrino masses and mixings in agreement with current neutrino oscillation data. The model leads to striking signals at future colliders through the R-parity violating decays of the lightest supersymmetric particle. Here we study charged scalar lepton decays and demonstrate th

P. M. Nadolsky, N. Kidonakis, F. Olness, C. -P. Yuan

When the energy of the heavy quark is comparable with its mass, it is natural to attribute this heavy quark to the hard part of the reaction. At large energies, this approach is impractical due to large logarithms from intensive QCD radiation affecting both inclusive and differential observables. We present a formalism for all-order summation of such logarit

J. Bartelski, S. Tatur

In order to determine polarized parton distributions we have made a new NLO QCD fit using all experimental data on spin asymmetries measured in the deep inelastic scattering on different nucleon targets. The functional form of such densities is based on MRST 2001 results for unpolarized ones . We get for polarization of quarks (at Q^2 = 1 GeV^2): Delta u = 0

Santo Fortunato

The critical behaviour of several spin models can be simply described as percolation of some suitably defined clusters, or droplets: the onset of the geometrical transition coincides with the critical point and the percolation exponents are equal to the thermal exponents. It is still unknown whether, given a model, one can define at all the droplets. In the

R. Van Kooten

The B physics program planned for the D0 Upgrade Detector for Run 2 of the Tevatron is described. Current performance of the detector pertinent to B physics is presented and compared to expectations. Detection of b hadrons through semileptonic decay and lifetime information is shown and some examples of prospects for the future given.

A. G. Shamov, V. I. Telnov

The application of the two-photon process pp -> pp + mu^+mu^- for the luminosity measurements at LHC with the ATLAS detector is considered. The expected accuracy of the absolute offline luminosity determination is 1 - 2 % for the luminosity range of 10^{33} - 10^{34} cm^-2 s^-1. The preliminary cross section estimates done for LHCb promise the same level of

Valery Telnov

Photon colliders (gamma-gamma, gamma-electron) are based on backward Compton scattering of laser light off the high energy electrons in linear colliders. All projects of linear colliders include this option. In this paper physics motivation, possible parameters and some interaction region aspects of photon colliders are discussed.

B. Aubert

We report preliminary results of an experimental investigation of the color-suppressed decays bar{B^0} --> D^0 pi^0, D^0 eta, and D^0 omega. We measure the branching fractions B (bar{B^0} --> D^0 pi^0) = (2.89 +/- 0.29 (stat.) +/- 0.38 (syst.)) times 10^{-4}, B (\bar{B^0} \to D^0 η) = (2.41 \pm 0.39 (stat.) +/- 0.32 (syst.)) times 10^{-4}, and B (bar{B^0} --

Massimo Giovannini

The scalar normal modes of higher dimensional gravitating kink solutions are derived. By perturbing to second order the gravity and matter parts of the action in the background of a five-dimensional kink, the effective Lagrangian of the scalar fluctuations is derived and diagonalized in terms of a single degree of freedom which invariant under infinitesimal

Raymond Y. Chiao

Superconductors will be considered as macroscopic quantum gravitational antennas and transducers, which can directly convert upon reflection a beam of quadrupolar electromagnetic radiation into gravitational radiation, and vice versa, and thus serve as practical laboratory sources and receivers of microwave and other radio-frequency gravitational waves. An e

Avery Ching, Alok Choudhary, Wei-keng Liao, Rob Ross

With the tremendous advances in processor and memory technology, I/O has risen to become the bottleneck in high-performance computing for many applications. The development of parallel file systems has helped to ease the performance gap, but I/O still remains an area needing significant performance improvement. Research has found that noncontiguous I/O acces

Mitchell J. Feigenbaum

We consider Saffman-Taylor channel flow without surface tension on a high-pressure driven interface, but modify the usual infinite-fluid in infinite-channel configuration. Here we include the treatment of efflux by considering a finite connected body of fluid in an arbitrarily long channel, with its second free interface the efflux of this configuration. We

W. T. Lu, J. B. Sokoloff, S. Sridhar

Wave refraction in negative-index media is always negative.

V. G. Kogan

The free energy is evaluated for a uniaxial superconductor with the anisotropy of the upper critical field, gamma_H = H_{c2,ab}/H_{c2,c}, different from the anisotropy of the penetration depth gamma_{lambda} = lambda_c/lambda_{ab}. With increasing difference between gamma_H and gamma_{lambda}, the equilibrium orientation of the crystal relative to the applie

S. V. Dordevic, Seiki Komiya, Yoichi Ando, Y. J. Wang

We report the results of the c-axis infrared spectroscopy of La_{2-x} Sr_x CuO_4 in high magnetic field oriented parallel to the CuO_2 planes. A significant suppression of the superfluid density with magnetic field rho_s(H) is observed for both underdoped (x=0.125) and overdoped (x=0.17) samples. We show that the existing theoretical models of the Josephson

Vladimir Kobelev, Anatoly B. Kolomeisky

Systems of charged particles on anisotropic three-dimensional lattices are investigated theoretically using Debye-Huckel theory. It is found that the thermodynamics of these systems strongly depends on the degree of anisotropy. For weakly anisotropic simple cubic lattices, the results indicate the existence of order-disorder phase transitions and a tricritic

I. M. Sokolov

The energetic efficiencies of rocked ratchets reported in the literature typically lie in the sub-percent range. We discuss the problem of optimization of the energetic efficiency of a ratchet, and show that considerably higher efficiencies can be achieved; however this assumes a fine-tuning of the parameters of the system. The domain of parameters correspon

J. Bouttier, P. Di Francesco, E. Guitter

We consider the problem of enumeration of planar maps and revisit its one-matrix model solution in the light of recent combinatorial techniques involving conjugated trees. We adapt and generalize these techniques so as to give an alternative and purely combinatorial solution to the problem of counting arbitrary planar maps with prescribed vertex degrees.

M. Degli Esposti, C. Giardina', S. Graffi

The Random Orthogonal Model (ROM) of Marinari-Parisi-Ritort [MPR1,MPR2] is a model of statistical mechanics where the couplings among the spins are defined by a matrix chosen randomly within the orthogonal ensemble. It reproduces the most relevant properties of the Parisi solution of the Sherrington-Kirckpatrick model. Here we compute the energy distribution

J. Hayoz, C. Koitzsch, M. Bovet, D. Naumovic

Yttrium can be loaded with hydrogen up to high concentrations causing dramatic structural and electronic changes of the host lattice. We report on angle-resolved photoemission experiments of the Y trihydride phase. Most importantly, we find the absence of metal d-bands at the Fermi level and a set of flat, H-induced bands located at much higher binding energ

D. A. Tennant, C. Broholm, D. H. Reich, S. E. Nagler

We report measurements of the two-magnon states in a dimerized antiferromagnetic chain material, copper nitrate (Cu(NO3)2*2.5D2O). Using inelastic neutron scattering we have measured the one and two magnon excitation spectra in a large single crystal. The data are in excellent agreement with a perturbative expansion of the alternating Heisenberg Hamiltonian

Ross Rinaldi, Adriana Biasco, Giuseppe Maruccio, Roberto Cingolani

Recently, great attention has been paid to the possibility of implementing hybrid electronic devices exploiting the self-assembling properties of single molecules. Impressive progress has been done in this field by using organic molecules and macromolecules. However, the use of biomolecules is of great interest because of their larger size (few nanometers) a

E. Paune, J. Casademunt

A nonlocal interface equation is derived for two-phase fluid flow, with arbitrary wettability and viscosity contrast c=(mu_1-mu_2)/(mu_1+mu_2), in a model porous medium defined as a Hele-Shaw cell with random gap b_0+delta b. Fluctuations of both capillary and viscous pressure are explicitly related to the microscopic quenched disorder, yielding conserved, n

W. Iwo Babiaczyk, Bogdan. R. Bulka

We performed studies of coherent electronic transport through a single walled carbon nanotube. In the calculations multiple scattering on the contacts and interference processes were taken into account. Conductance is a composition of contributions from different channels. We studied also spin--dependent transport in the system with ferromagnetic electrodes.

F. J. Jedema, M. V. Costache, H. B. Heersche, J. J. A. Baselmans

We have fabricated a multi terminal lateral mesoscopic metallic spin valve demonstrating spin precession at room temperature, using tunnel barriers in combination with metallic ferromagnetic electrodes as spin injector and detector. The observed modulation of the output signal due to the spin precession is discussed and explained in terms of a time of flight

Toru Moriya

We summarize the present status of the theories of spin fluctuations in dealing with the anomalous or non-Fermi liquid behavior and unconventional superconductivity in strongly correlated electron systems around their magnetic instabilities or quantum critical points. Arguments are given to indicate that the spin fluctuation mechanisms is the common origin o

P. Provero

We construct a gene network based on expression data from DNA microarray experiments, by establishing a link between two genes whenever the Pearson's correlation coefficient between their expression profiles is higher than a certain cutoff. The resulting connectivity distribution is compatible with a power-law decay with exponent ~1, corrected by an expo

Nir J. Shaviv

Several of the inconsistencies plaguing the field of novae are resolved once we consider novae to be steady state super-Eddington objects. In particular, we show that the super-Eddington shell burning state is a natural consequence of the equations of stellar structure, and that the predicted mass loss in the super-Eddington state agrees with nova observatio

Paul N. Arendt, Jean A. Eilek

We present numerical simulations of the electron-positron plasma creation process in a simple neutron star magnetosphere. We have developed a set of cascade `kernels', which represent the endpoint of the pair cascades resulting from monoenergetic photon seeds. We explore two popular models by convolving these kernels with the seed photon distributions pr

Nir J. Shaviv

We construct a Galactic cosmic ray (CR) diffusion model while considering that CR sources reside predominantly in the Galactic spiral arms. We find that the CR flux (CRF) reaching the solar system should periodically increase each crossing of a Galactic spiral arm. We search for this signal in the CR exposure age record of Iron meteorites and confirm this pr

L. Decin, B. Vandenbussche, C. Waelkens, K. Eriksson

Vega, Sirius, Beta Leo, Alpha Car and Alpha Cen A belong to a sample of twenty stellar sources used for the calibration of the detectors of the Short-Wavelength Spectrometer on board the Infrared Space Observatory (ISO-SWS). While general problems with the calibration and with the theoretical modelling of these stars are reported in Decin et al. (2002), each

Donald P. Cox, Gilberto C. Gomez

When modeling the three-dimensional hydrodynamics of interstellar material rotating in a galactic gravitational potential, it is useful to have an analytic expression for gravitational perturbations due to stellar spiral arms. We present such an expression for which changes in the assumed characteristics of the arms can be made easily and the sensitivity of

Gilberto C. Gomez, Donald P. Cox

We show the initial results of our 3D MHD simulations of the flow of the Galactic atmosphere as it responds to a spiral perturbation in the potential. In our standard case, as the gas approaches the arm, there is a downward converging flow that terminates in a complex of shocks just ahead of the midplane density peak. The density maximum slants forward at hi

Gilbert P. Holder

We predict the level of small-scale anisotropy in the cosmic microwave background (CMB) due to the Sunyaev--Zel'dovich (SZ) effect for the ensemble of cosmological models that are consistent with current measurements of large-scale CMB anisotropy. We argue that the recently reported detections of the small-scale (arcminutes) CMB anisotropy are only margi

Ignacio Ferreras, Joseph Silk

Using the standard prescription for the rates of supernovae type II and type Ia, we compare the predictions of a simple model of star formation in galaxies with the observed radial gradients of abundance ratios in a sample of early-type galaxies to infer the relative contribution of each type of supernova. The data suggests a correlation between the fraction

Hugo Martel, Paul R. Shapiro

The gravitational lensing properties of cosmological halos depend upon the mass distribution within each halo. The description of halos as nonsingular, truncated isothermal spheres, a particular solution of the isothermal Lane- Emden equation (suitably modified for Lambda non equal 0), has proved to be a useful approximation for the halos which form from rea

M. J. Claussen, W. M. Goss, K. M. Desai, C. L. Brogan

We have used the NRAO Very Large Array (VLA) in conjunction with the Very Long Baseline Array (VLBA) Pie Town antenna as a real-time interferometer system to measure the size of the extragalactic source J1801-231 as a function of frequency from 1285 to 4885 MHz. These observations were made in an attempt to determine the effect interstellar scattering has on

M. Hernanz, R. Gonzalez-Riestra, W. Wamsteker, B. Shustov

We summarize the capabilities of the World Space Observatory (UV) Project (WSO/UV). An example of the importance of this project (with a planned launch date of 2007/8) for the study of Classical Novae is given.

Jeffrey S. Bary, David A. Weintraub, Joel H. Kastner

Astronomers have established that for a few million years newborn stars possess disks of orbiting gas and dust. Such disks, which are likely sites of planet formation, appear to disappear once these stars reach ages of 5-10 times 10^6 yr; yet, >= 10^7 yr is thought necessary for giant planet formation. If disks dissipate in less time than is needed for giant

G. S. Bisnovatyi-Kogan, R. V. E. Lovelace

Accretion disk theory was first developed as a theory with the local heat balance, where the whole energy produced by a viscous heating was emitted to the sides of the disk. One of the most important new invention of this theory was the phenomenological treatment of the turbulent viscosity, known the `` alpha'' prescription, where the (r phi) compone

Michael A. Nowak

As described in the review by Marek Abramowicz (these proceedings), accretion theory is at something of a crossroads. Many theoretical descriptions of observations have centered on the ``hydrodynamic'' approach of the ``standard'' Shakura & Sunyaev alpha-disk; however, recent MHD simulations of (non-radiative) accretion flow have called into

Christopher J. Deloye, Lars Bildsten

We assess the impact of the trace element ^{22}Ne on the cooling and seismology of a liquid C/O white dwarf (WD). Due to this elements' neutron excess, it sinks towards the interior as the liquid WD cools. The subsequent gravitational energy released slows the cooling of the WD by 0.25--1.6 Gyrs by the time it has completely crystallized, depending on th

L. Decin, B. Vandenbussche, C. Waelkens, K. Eriksson

The fine calibration of the ISO-SWS detectors (Infrared Space Observatory - Short Wavelength Spectrometer) has proven to be a delicate problem. We therefore present a detailed spectroscopic study in the 2.38 -- 12 micron wavelength range of a sample of 16 A0 -- M2 stars used for the calibration of ISO-SWS. By investigating the discrepancies between the ISO-S

M. -R. L. Cioni

There are three important aspects concerning the study of the red giant and in particular of the asymptotic giant branch (AGB) stars in the Magellanic Clouds. These are: the surface distribution, the luminosity function and the variability. The spatial distribution of AGB stars is an efficient tool to study the structure of the galaxies and their metalicity

A. Djannati-Atai, B. Khelifi, S. Vorobiov, R. Bazer-Bachi

The BL Lac Object 1ES 1426+428, at a red-shift of z=0.129, has been monitored by the CAT telescope from February 1998 to June 2000. The accumulation of 26 hours of observations shows a gamma-ray signal of 321 events above 250 GeV at 5.2 standard deviations, determined using data analysis cuts adapted to a weak, steep-spectrum source. The source emission has

Joachim Wambsganss

Gravitational lensing is a powerful tool to detect compact matter on very different mass scales. Of particular importance is the fact that lensing is sensitive to both luminous and dark matter alike. Depending on the mass scale, all lensing effects are used in the search for matter: offset in position, image distortion, magnification, and multiple images. Gr

G. Matt

We calculate the Equivalent Widht of the Core and the centroid energy and relative flux of the 1st order Compton Shoulder of the iron Kalpha emission line from neutral matter. The calculations are performed with Monte Carlo simulations. We explore a large range of column densities for both transmitted and reflected spectra, and study the dependence on the ir

J. Meaburn, M. F. Graham, M. P. Redman

A spatially unresolved velocity feature, with an approaching radial velocity of ~100 km/s with respect to the systemic radial velocity, in a position-velocity array of [O III] 5007 line profiles is identified as the kinematical counterpart of a jet from the proplyd LV 5 (158-323) in the core of the Orion Nebula. The only candidate in HST imagery for this jet

A. Pasquali, A. Nota, L. J. Smith, S. Akiyama

We present high resolution HST imaging of the nebula associated with the galactic LBV candidate HD 168625, together with ISO imaging and AAT echelle spectroscopy. The overall nebular morphology is elliptical with the major axis at PA ~ 120 deg. The dimensions of the nebula are 12'' x 16''.7 at Halpha and 15''.5 x 23''.5 at 4 m

Sun Hong Rhie

Criticality in graviational microlensing is an everyday issue because that is what generates microlensing signals which may be of photon-challenged compact objects such as black holes or planetary systems ET calls home. The criticality of these quasi-analytic lenses is intrinsically quadratic, and the critical curve behaves as a mirror generating two mirror

T. Kato, R. Stubbings, H. Yamaok, P. Nelson

NSV 10934 was discovered as a large-amplitude suspected variable star of unknown classification. We noticed that the object is identified with a bright ROSAT X-ray source (1RXS J184050.3-834305). Systematic monitoring of this object by the VSNET team revealed four outbursts between 2001 and 2002, confirming the dwarf nova-type nature of NSV 10934. The outbur

T. Gleissner, J. Wilms, K. Pottschmidt, P. Uttley

A linear dependence of the amplitude of broadband noise variability on flux for GBHC and AGN has been recently shown by Uttley & McHardy (2001). We present the long term evolution of this rms-flux-relation for Cyg X-1 as monitored from 1998-2002 with RXTE. We confirm the linear relationship in the hard state and analyze the evolution of the correlation for t

G. L. Comer

Isolated neutron stars undergoing non-radial oscillations are expected to emit gravitational waves in the kilohertz frequency range. To date, radio astronomers have located about 1,300 pulsars, and can estimate that there are about 2 times 10^8 neutron stars in the galaxy. Many of these are surely old and cold enough that their interiors will contain matter

Douglas C. Leonard, Alexei V. Filippenko, Weidong Li, Thomas Matheson

We present optical spectra and photometry sampling the first six months after discovery of supernova (SN) 1999gi in NGC 3184. SN 1999gi is shown to be a Type II-plateau event with a photometric plateau lasting until about 100 days after discovery. The reddening values resulting from five independent techniques are all consistent with an upper bound of E(B-V)

V. A. Zheligovsky, O. M. Podvigina

We study generation of magnetic fields involving large spatial scales by time- and space-periodic small-scale parity-invariant flows. The anisotropic magnetic eddy diffusivity tensor is calculated by the standard procedure involving expansion of magnetic modes and their growth rates in power series in the scale ratio. Our simulations, conducted for flows wit

Jin-Ho Cho, Taejin Lee, Soonkeon Nam

We investigate various aspects of the plane wave geometries obtained from D1/D5-brane system. We study the effect of Hopf-duality on the supersymmetries preserved by the Penrose limit of $AdS_3\times S^3\times T^4$ geometry. In type-IIB case, we first show that the Penrose limit makes the size of the `would-be' internal torus comparable to that of the other

Alexander Kovner, Urs Achim Wiedemann

In the previous work hep-ph/0112140, hep-ph/0204277, we showed that while the nonlinear QCD evolution equation of Balitsky and Kovchegov (BK) leads to saturation of the scattering amplitude locally in impact parameter space, it does not unitarize the total cross section. This result was recently challenged by Ferreiro, Iancu, Itakura and McLerran (FIIM) who

Ram Brustein, David H. Oaknin

It is shown that the vacuum state of weakly interacting quantum field theories can be described, in the Heisenberg picture, as a linear combination of randomly distributed incoherent paths that obey classical equations of motion with constrained initial conditions. We call such paths "pseudoclassical" paths and use them to define the dynamics of quan

M. Paternostro, M. S. Kim, B. S. Ham

The generation of an entangled coherent state is one of the most important ingredients of quantum information processing using coherent states. Recently, numerous schemes to achieve this task have been proposed. In order to generate travelling-wave entangled coherent states, cross phase modulation, optimized by optical Kerr effect enhancement in a dense medi

J. Ponce de Leon

In classical Kaluza-Klein theory, with compactified extra dimensions and without scalar field, the rest mass as well as the electric charge of test particles are constants of motion. We show that in the case of a large extra dimension this is no longer so. We propose the Hamilton-Jacobi formalism, instead of the geodesic equation, for the study of test parti

Ryo Yamazaki, Kunihito Ioka, Takashi Nakamura

If X-ray flashes are due to the forward jet emissions from gamma ray bursts (GRBs) observed with large viewing angles, we show that a prompt emission from a counter jet should be observed as a delayed flash in the UV or optical band several hours to a day after the X-ray flash. Ultraviolet and Optical Telescope on Swift can observe the delayed flashes within

S. J. Akhtarshenas, M. A. Jafarizadeh

We propose a simple geometrical approach for finding the Lewenstein-Sanpera decomposition of Bell decomposable states of 2 otimes 2 quantum systems. We show that in these systems, the weight of the pure entangled part in the decomposition is equal to the concurrence of the state. It is also shown that the optimized separable part of L-S decomposition minimiz

M. K. Gaidarov, M. V. Ivanov, A. N. Antonov

The concept of relativistic scaling is applied to describe the most recent data from inclusive electron-deuteron scattering at large momentum transfer. We calculate the asymptotic scaling function f(y) of the deuteron using its relationship with the nucleon momentum distribution. The latter is obtained in the framework of the relativistic light-front dynamic

A. P. Kostyuk, H. Stoecker, W. Greiner

The recently published experimental dependence of the J/psi suppression pattern in Pb+Pb collisions at the CERN SPS on the energy of zero degree calorimeter E_ZDC are analyzed. It is found that the data obtained within the `minimum bias' analysis (using `theoretical Drell-Yan') are at variance with the previously published experimental dependence of

M. A. R. de Cara, O. Pla, F. Guinea, J. L. Tella

We introduce here three complementary models to analyze the role of predation pressure in avian coloniality. Different explanations have been proposed for the existence of colonial breeding behavior in birds, but field studies offer no conclusive results. We first propose a learning model in which the decision of birds are taken according to the collective p

Mikhail Khovanov

We prove that the construction of our previous paper math.QA/0103190 yields an invariant of tangle cobordisms.