August 1998 arXiv papers — page 11

G. D'Anna, V. Berseth, L. Forro, A. Erb

Sub-nanovolt resolution longitudinal and Hall voltages are measured in an ultra pure YBa2Cu3O7-d single crystal. The Hall anomaly and the first-order vortex-lattice melting transition are observed simultaneously. Changes in the dynamic behavior of the vortex solid and liquid are correlated with features of the Hall conductivity sxy. With the magnetic field o

R. Yu. Abdulsabirov, A. A. Bukharaev, M. R. Zhdanov, R. Sh. Zhdanov

Predicted earlier, microcracks on the crystal surface of both finely dispersed $LiYF_4$ powders and single crystals of the Van Vleck paramagnet $% LiTmF_4$ were detected by using the NMR Cryoporometry and Atomic-Force Microscopy technique.

John N. Bahcall

I review recent developments that affect standard solar model predictions of solar neutrino fluxes.

O. D. Miranda, M. Opher, R. Opher

The origin of the magnetic field in galaxies is an open question in astrophysics. Several mechanisms have been proposed related, in general, with the generation of small seed fields amplified by a dynamo mechanism. In general, these mechanisms have difficulty in satisfying both the requirements of a sufficiently high strength for the magnetic field and the n

Osamu Iguchi, Tomomi Kurokawa, Masahiro Morikawa, Akika Nakamichi

We study statistical mechanics of the self--gravitating system applying the cluster expansion method developed in solid state physics. By summing infinite series of diagrams, we derive a complex free energy whose imaginary part is related to the relaxation time of the system. Summation of another series yields two--point correlation function whose correlatio

NA44 Collaboration, H. Boggild et al

The NA44 collaboration has measured charged kaon and pion distributions at midrapidity in sulphur and proton collisions with nuclear targets at 200 and 450 GeV/c per nucleon, respectively. The inverse slopes of kaons are larger than those of pions. The difference in the inverse slopes of pions, kaons and protons, all measured in our spectrometer, increases w

M. Jaime, P. Lin, S. H. Chun, M. B. Salamon

We explore the possibility that polaronic distortions in the paramagnetic phase of La$_{0.67}$Ca$_{0.33}$MnO$_3$ manganites persist in the ferromagnetic phase by considering the observed electrical resistivity to arise from coexisting field- and temperature-dependent polaronic and band-electron fractions. We use an effective medium approach to compute the to

Inyong Cho, Alexander Vilenkin

Topological defects can arise in symmetry breaking models where the scalar field potential $V(\phi)$ has no minima and is a monotonically decreasing function of $|\phi|$. The properties of such vacuumless defects are quite different from those of the ``usual'' strings and monopoles. In some models such defects can serve as seeds for structure formation, or p

Danny Calegari

We produce examples of taut foliations of hyperbolic 3-manifolds which are R-covered but not uniform --- ie the leaf space of the universal cover is R, but pairs of leaves are not contained in bounded neighborhoods of each other. This answers in the negative a conjecture of Thurston `Three-manifolds, foliations and circles I' (math.GT/9712268). We furthe

R. Kallosh, A. A. Tseytlin

Type IIB string action on AdS_5 x S^5 constructed in hep-th/9805028 is put into a form where it becomes quadratic in fermions. This is achieved by performing 2-d duality (T-duality) on the action in which kappa-symmetry was fixed in the Killing gauge in hep-th/9808038. We discuss some properties and possible applications of the resulting action.

Robert E. Gompf

We construct closed symplectic manifolds for which spherical classes generate arbitrarily large subspaces in 2-homology, such that the first Chern class and cohomology class of the symplectic form both vanish on all spherical classes. We construct both Kaehler and non-Kaehler examples, and show independence of the conditions that these two cohomology classes

Riccardo Barbieri, Lawrence J. Hall, Alessandro Strumia

In theories with three light neutrinos, a complete list of five zeroth-order textures for lepton mass matrices is found, which naturally yield: m_e = m_mu=0, m_tau \neq 0, Delta m^2_sun = 0, together with theta_{e tau} = 0, theta_{mu tau} approx 1. These textures provide suitable starting points for constructing theories which account for both atmospheric an

C. P. Burgess, A. de la Macorra, I. Maksymyk, F. Quevedo

We study the dilaton-dependence of the effective action for N=1, SU(N1) x SU(N2) models with one generation of vectorlike matter transforming in the fundamental of both groups. We treat in detail the confining and Coulomb phases of these models writing explicit expressions in many cases for the effective superpotential. We can do so for the Wilson superpoten

P E Kornilovitch

An efficient continuous-time path-integral Quantum Monte Carlo algorithm for the lattice polaron is presented. It is based on Feynman's integration of phonons and subsequent simulation of the resulting single-particle self-interacting system. The method is free from the finite-size and finite-time-step errors and works in any dimensionality and for any r

Arundhati Dasgupta

The emission rate of fermions from 2+1 dimensional BTZ black holes is shown to have a form which can be reproduced from a conformal field theory at finite temperature. The rate obtained for fermions is identical to the rate of non-minimally coupled fermions emitted from a five dimensional black hole, whose near horizon geometry is BTZ X M, where M is a compa

Biswajoy Brahmachari

We take up the point of view that Yukawa couplings can be either 0 or 1, and the mass patterns of fermions are generated purely from the structure of the Yukawa matrices. We utilize such neutrino as well as charged leptonic textures which lead to (maximal) mixing angles of $π/4$ in each sector for relevant transitions. The combined leptonic CKM mixing angles

S. W. Hawking, C. J. Hunter

The underlying reason for the existence of gravitational entropy is traced to the impossibility of foliating topologically non-trivial Euclidean spacetimes with a time function to give a unitary Hamiltonian evolution. In $d$ dimensions the entropy can be expressed in terms of the $d-2$ obstructions to foliation, bolts and Misner strings, by a universal formu

Thomas D. Cohen, James M. Hansen

Low energy theorems are derived for the coefficients of the effective range expansion in s-wave nucleon-nucleon scattering valid to leading order in an expansion in which both $m_π$ and $1/a$ (where $a$ is the scattering length) are treated as small mass scales. Comparisons with phase shift data, however, reveal a pattern of gross violations of the theorems

L. Neubert, H. Y. Lee, M. Schreckenberg

In this paper computer simulation results of higher order density correlation for cellular automaton models of traffic flow are presented. The examinations show the jamming transition as a function of both the density and the magnitude of noise and allow to calculate the velocity of upstream moving jams. This velocity is independent of the density and decrea

Soumitro Banerjee, Celso Grebogi

Recent investigations on the bifurcations in switching circuits have shown that many atypical bifurcations can occur in piecewise smooth maps which can not be classified among the generic cases like saddle-node, pitchfork or Hopf bifurcations occurring in smooth maps. In this paper we first present experimental results to establish the need for the developme

R. Resta, S. Sorella

The insulating state of matter is characterized by the excitation spectrum, but also by qualitative features of the electronic ground state. The insulating ground wavefunction in fact: (i) sustains macroscopic polarization, and (ii) is localized. We give a sharp definition of the latter concept, and we show how the two basic features stem from essentially th

M. Ciuchini, L. Conti, A. Donini, E. Franco

We perform a Next-to-Leading order analysis of Delta S=2 processes beyond the Standard Model. Combining the recently computed NLO anomalous dimensions and the B parameters of the most general Delta S=2 effective Hamiltonian, we give an analytic formula for Delta M_K and epsilon_K in terms of the Wilson coefficients at the high energy scale. This expression c

Tomaz Prosen

We study a generic but simple non-integrable quantum {\em many-body} system of {\em locally} interacting particles, namely a kicked $t-V$ model of spinless fermions on 1-dim lattice (equivalent to a kicked Heisenberg XX-Z chain of 1/2 spins). Statistical properties of dynamics (quantum ergodicity and quantum mixing) and the nature of quantum transport in {\e

Masahide Yamaguchi, Jun'ichi Yokoyama, M. Kawasaki

We simulate the formation and the evolution of global strings taking into account the expansion of the universe and the concomitant change of the effective potential, that is, the change from the restoration stage of the global {\it U}(1)-symmetry to the broken stage. Starting from the thermal equilibrium state, we run simulations for 100 sets of different i

S. Schinzer, M. Kinne, M. Biehl, W. Kinzel

The role of step edge diffusion (SED) in epitaxial growth is investigated. To this end we revisit and extend a recently introduced simple cubic solid-on-solid model, which exhibits the formation and coarsening of pyramid or mound like structures. By comparing the limiting cases of absent, very fast (significant), and slow SED we demonstrate how the details o

Benno Fuchssteiner, Wen-Xiu Ma

An approach to master symmetries of lattice equations is proposed by the use of discrete zero curvature equation. Its key is to generate non-isospectral flows from the discrete spectral problem associated with a given lattice equation. A Volterra-type lattice hierarchy and the Toda lattice hierarchy are analyzed as two illustrative examples.

J. L. Roberts, N. R. Claussen, James P. Burke,, Chris H. Greene

A magnetic field dependent Feshbach resonance has been observed in the elastic scattering collision rate between atoms in the F = 2, M = -2 state of 85 Rb. Changing the magnetic field by several Gauss caused the collision rate to vary by a factor of 10,000, and the sign of the scattering length could be reserved. The resonance peak is at 155.2(4) G and its w

T. Detmer, P. Schmelcher, L. S. Cederbaum

A basis set of generalized nonspherical Gaussian functions (GGTOs) is presented and discussed. As a first example we report on Born-Oppenheimer energies of the hydrogen molecule. Although accurate results have been obtained, we conclude that H_2 is too 'simple' to allow for a substantial gain by using nonspherical functions. We rather expect that the

Eric Baird

Simple signal-propagation effects make receding objects seem contracted and approaching objects seem elongated. These effects are theoretically photographable, and are proportional in strength to the frequency-change in the object's emitted light. In a one-dimensional version of the "barn-pole" experiment, a "moving" object's photogra

Michael Uzzo, Franz Gross

Mesons are made of quark-antiquark pairs held together by the strong force. The one channel spectator, Dirac, and Salpeter equations can each be used to model this pairing. We look at cases where the relativistic kernel of these equations corresponds to a time-like vector exchange, a scalar exchange, or a linear combination of the two. Since the model used i

B. V. Carlson, M. S. Hussein, A. F. R. de Toledo Piza

The decay theory of double giant resonances incorporating fluctuation contributions of the Brink-Axel type is developed. The gamma and neutron emission decay of Double Giant Dipole Resonances (DGDR) in 208Pb is discussed in connection with a recent measurement.

B. V. Carlson, L. F. Canto, S. Cruz-Barrios, M. S. Hussein

We argue that a substantial increase in the cross section for Coulomb excitation in the region of the Double Giant Dipole Resonance should be expected from Coulomb excitation of excited states involved in the spreading of the one-phonon resonance, in a manifestation of the Brink-Axel phenomenon. This generates an additional fluctuating amplitude and a corres

E. Garrido, D. V. Fedorov, A. S. Jensen

We use the three-body model and the sudden approximation to compute angular correlations in high-energy fragmentation reactions of two-neutron halos on light targets. The contribution from one-neutron absorption by far dominates over that of neutron scattering. We use 6He (n+n+alpha) and 11Li (n+n+9Li) as examples and study the dependence of the predictions

Stefan G. Frauendorf, Javid A. Sheikh

A cranked shell model approach for the description of rotational bands in $N\approx Z$ nuclei is formulated. The isovector neutron-proton pairing is taken into account explicitly. The concept of spontaneous breaking and subsequent restoration of the isospin symmetry turns out to be crucial. The general rules to construct the near yrast-spectra for rotating n

Sheldon Axler, Zeljko Cuckovic, N. V. Rao

In this note we show that if two Toeplitz operators on a Bergman space commute and the symbol of one of them is analytic and nonconstant, then the other one is also analytic.

Pavel Etingof, Vladimir Retakh

The notion of a quasideterminant and a quasiminor of a matrix A=(a_{ij}) with not necessarily commuting entries was introduced recently by I.Gelfand and the second author. The ordinary determinant of a matrix with commuting entries can be written (in many ways) as a product of quasiminors. Furthermore, it was noticed by a number of authors that such well-kno

Jimmy Petean

We prove that the Yamabe invariant of any simply connected smooth manifold of dimension n greater than four is non-negative. Equivalently that the infimum of the L^{n/2} norm of the scalar curvature, over the space of all Riemannian metrics on the manifold, is zero.

Mihail N. Kolountzakis

A set ${\cal A} \subseteq \Set{1,...,N}$ is of type $B_2$ if all sums $a+b$, with $a\ge b$, $a,b\in {\cal A}$, are distinct. It is well known that the largest such set is of size asymptotic to $N^{1/2}$. For a $B_2$ set ${\cal A}$ of this size we show that, under mild assumptions on the size of the modulus $m$ and on the difference $N^{1/2}-\Abs{\cal A}$ (th

Daniel Matei, Alexander I. Suciu

We study the homotopy types of complements of arrangements of n transverse planes in R^4, obtaining a complete classification for n <= 6, and lower bounds for the number of homotopy types in general. Furthermore, we show that the homotopy type of a 2-arrangement in R^4 is not determined by the cohomology ring, thereby answering a question of Ziegler. The inv

Yishi Duan, Sheng Li

The space-time disclination is studied by making use of the decomposition theory of gauge potential in terms of antisymmetric tensor field and $ϕ$-mapping method. It is shown that the self-dual and anti-self-dual parts of the curvature compose the space-time disclinations which are classified in terms of topological invariants--winding number. The projection

Cong-xin Liu, Guo-xing Ju, Shi-kun Wang, Ke Wu

The symmetries, especially those related to the $R$-transformation, of the reflection equation(RE) for two-component systems are analyzed. The classification of solutions to the RE for eight-, six- and seven-vertex type $R$-matrices is given. All solutions can be obtained from those corresponding to the standard $R$-matrices by $K$-transformation. For the fr

Michael R. Douglas, Washington Taylor

We consider (3 + 1)-dimensional N=4 super Yang-Mills theory with a nonvanishing scalar Higgs vacuum expectation value, and compare this theory to AdS supergravity with branes in the bulk. We show that the one-loop effective potential for excitations of the Yang-Mills field agrees with the classical linearized potential for brane waves in the AdS picture in t

M. Vänttinen, G. Piller, L. Mankiewicz, W. Weise

In coordinate space, quark and gluon distributions of the nucleon are defined as correlation functions involving two field operators separated by a light-cone distance $y^+ = 2l$. We study the nuclear modifications of these distributions. The largest effect is a strong depletion of parton distributions (shadowing) at large longitudinal distances, which start

Cai-Dian Lu

We calculate the two-body nonleptonic B decays using the factorization method. The recent measured decays by CLEO Collaboration can be explained in the factorization approach. We propose a number of ratios of branching ratios to determine the effective coefficients and the form factors.

Gabriela Barenboim, Florian Scheck

It is shown that it is possible to account for all experimental indications for neutrino oscillations with just three flavours. In particular we suggest that the atmospheric neutrino anomaly and the LSND result can be explained by the same mass difference and mixing. Possible implications and future tests of the resulting mass and mixing pattern are given.

G. H. Arakelyan, Sh. S. Yeremyan

The hadroproduction of $D_s$ mesons is discussed within the framework of the modified Quark-Gluon String model (QGSM) taking into account the decays of corresponding $S$--wave resonances. A description of the existing experimental data on inclusive spectra of $D_s$ - mesons production in $πp$ - collision and asymmetry of leading ($D_s^-$) and nonleading ($D_

Shigeru Yoshida, Guenter Sigl, Sangjin Lee

Extremely high energy (up to 10**(22) eV) cosmic neutrino beams initiate high energy particle cascades in the background of relic neutrinos from the Big Bang. We perform numerical calculations to show that such cascades could contribute more than 10% to the observed cosmic ray flux above 10**(19) eV if neutrinos have masses in the electron volt range. The re

Daniel J. H. Chung

If there exist fields of mass of the order of $10^{13}$ GeV and large field inflation occurs, their interaction with classical gravitation will generate enough particles to give the universe critical density today regardless of their nongravitational coupling. This is mainly a summary of the work hep-ph/9802238.

I T Drummond

We present some simple scenarios for string breaking on the lattice based on a crude strong coupling model introduced previously. We review the dependence of the model on lattice spacing and extend it to include degenerate dynamical quarks and also meson exchange diagrams. A comparison is made between quenched and unquenched calculations. We examine string b

Stefan Sint, Peter Weisz

The non-perturbatively defined running quark mass introduced by the ALPHA collaboration is based on the PCAC relation between correlation functions derived from the Schrödinger functional (SF). In order to complete its definition it remains to specify a number of parameters, including the ratio of time to spatial extent, $T/L$, and the angle $θ$ which appear

The OPAL Collaboration, K. Ackerstaff et al

The branching ratios of the decay of the tau lepton to five charged hadrons have been measured with the OPAL detector at LEP using data collected between 1991 and 1995 at e+e- centre-of-mass energies close to the Z resonance. The branching ratios are measured to be BR(tau- to 3h-2h+nutau) = 0.091+-0.014+-0.005% BR(tau- to 3h-2h+pi0nutau) = 0.027+-0.018+-0.00

Erast B. Gliner

A class of exact regular spherically symmetric solutions to the Einstein equation obeying Dymnikova&#39;s definition of the vacuumlike state is considered. These solutions, which may be interpreted as black holes, are not only singularity free, but also do not set us thinking about the loss of information under gravitational collapse. According to the singul

Richard Easther

We show that two-field inflation can be followed by an era in which the field dynamics become chaotic, and discuss the possible consequences of this for two-field inflationary models. [PASCOS conference proceedings - a short version of gr-qc/9711035]

Takahiro Morishima, Toshifumi Futamase

We investigated the behavior of an open isotropic universe generated by a scalar field which couples with background curvature nonminimally with the coupling constant $ξ$. In particular we focus on the situation where the initial value for the scalar field $ϕ_{\rm in}$ is greater than the critical value ${\hat ϕ}_c$=${m_p}/{\sqrt{8πξ(1-6ξ)}}$. The behavior i

Masahiro Takada, Toshifumi Futamase

We point out the existence of a new type of growing transverse mode in the gravitational instability. This appears as a post-Newtonian effect to Newtonian dynamics. We demonstrate this existence by formulating the Lagrangian perturbation theory in the framework of the cosmological post-Newtonian approximation in general relativity. Such post-Newtonian order

E. Ben-Naim, P. L. Krapivsky

We investigate traffic flows using the kinetic Boltzmann equations with a Maxwell collision integral. This approach allows analytical determination of the transient behavior and the size distributions. The relaxation of the car and cluster velocity distributions towards steady state is characterized by a wide range of velocity dependent relaxation scales, $R

E. E. Narimanov, A. D. Stone

We develop a quantitative semiclassical theory for the resosnant tunneling through a quantum well in a tilted magnetic field. It is shown, that in the leading semiclassical approximation the tunneling current depends only on periodic orbits within the quantum well. Further corrections (due to e.g. &#34;ghost&#34; effect) can be expressed in terms of closed,

G. M. Luke, Y. Fudamoto, K. M. Kojima, M. I. Larkin

We report muon spin relaxation measurements on the superconductor Sr2RuO4 that reveal the spontaneous appearance of an internal magnetic field below the transition temperature: the appearance of such a field indicates that the superconducting state in this material is characterized by the breaking of time-reversal symmetry. These results, combined with other

S. J. Papadakis, E. P. De Poortere, M. Shayegan

We measure the effective Lande g-factor of high-mobility two-dimensional electrons in a modulation-doped AlAs quantum well by tilting the sample in a magnetic field and monitoring the evolution of the magnetoresistance oscillations. The data reveal that |g| = 9.0, which is much enhanced with respect to the reported bulk value of 1.9. Surprisingly, in a large

F. Tassone, R. Huang, Y. Yamamoto

The wavefunction of a collection of identical quantum particles of integer spin (bosons) is even under exchange of the coordinates of any two of them. This symmetrization rule of quantum mechanics leads to stimulation of the scattering rate into final states whose population is larger than one. For massless photons, it is routinely observed in the laser. For

Francesco Tassone, Carlo Piermarocchi

We present a self-consistent treatment of the electron-hole correlations in optically excited quantum wires within the ladder approximation, and using a contact potential interaction. The limitations of the ladder approximation to the excitonic low-density region are largely overcome by the introduction of higher order correlations through self consistency.

Cristian Micheletti, Amos Maritan

We present a detailed study of the performance and reliability of design procedures based on energy minimization. The analysis is carried out for model proteins where exact results can be obtained through exhaustive enumeration. The efficiency of design techniques is assessed as a function of protein lengths and number of classes into which amino acids are c

J-M Drouffe, C Godreche

For the two dimensional kinetic Ising model at finite temperature, the local mean magnetisation $M_t=t^{-1}\int_{0}^tσ(t&#39;)\d t&#39;$, simply related to the fraction of time spent by a given spin in the positive direction, has a limiting distribution, singular at $\pm m_0(T)$, the Onsager spontaneous magnetization. The exponent of this singularity defines

Hideaki Aoyama, John Constable

In this paper we build on earlier observations and theory regarding word length frequency and sequential distribution to develop a mathematical characterization of some of the language features distinguishing isometrically lineated text from unlineated text, in other words the features distinguishing isometrical verse from prose. It is shown that the frequen

A. Ptak, P. Serlemitsos, T. Yaqoob, R. Mushotzky

The results of a 0.4-10.0 keV ASCA spectral analysis of a sample of low-luminosity AGN (LLAGN; M51, NGC 3147, NGC 4258), low-ionization nuclear emission line regions (LINERs; NGC 3079, NGC 3310, NGC 3998, NGC 4579, NGC 4594) and starburst galaxies (M82, NGC 253, NGC 3628 and NGC 6946) are presented. In spite of the heterogeneous optical classifications of th

R. Giovanelli, M. Haynes, J. Salzer, G. Wegner

In preceding papers of this series, TF relations for galaxies in 24 clusters with radial velocities between 1000 and 9200 km/s (SCI sample) were obtained, a Tully-Fisher (TF) template relation was constructed and mean offsets of each cluster with respect to the template obtained. Here, an estimate of the line-of-sight peculiar velocities of the clusters and

Bradley E. Schaefer

The light curve of the Type Ia supernova SN1974G (in NGC4414) is important because the Hubble Space Telescope has measured the distance to the host galaxy by means of Cepheid variables and thus the Hubble Constant can be derived. Light curves from the secondary literature are inadequate since the majority of data is misreported, the majority of the published

G. Ghisellini, F. Haardt, S. Campana, D. Lazzati

If gamma-ray bursts originate in dense stellar forming regions, the interstellar material can imprint detectable absorption features on the observed X-ray spectrum. Such features can be detected by existing and planned X-ray satellites, as long as the X-ray afterglow is observed after a few minutes from the burst. If the column density of the interstellar ma

Sidney van den Bergh

The possibility that the Sagittarius dwarf spheroidal might have formed as a Searle-Zinn fragment in the outer halo of the Galaxy is discussed. Arguments in favor of this hypothesis are: (1) The luminosity distribution of globular clusters in both Sagittarius and in the outer halo (Rgc > 80 kpc), appear to be bimodal with peaks near MV ~ -5 and MV ~ -10, and

Amelia Stutz, Piotr Popowski, Andrew Gould

We compare (V-I)_0-(V-K)_0 color-color and (V-I)_0-log P period-color diagrams for Baade&#39;s Window and local RRab Lyrae stars. We find that for a fixed log P the Baade&#39;s Window RR Lyrae stars are ~0.17 magnitudes redder in (V-I)_0 than the local RR Lyrae stars. We also show that there is no such effect observed in (V-K)_0. We argue that an extinction

Lionel Siess, Mario Livio

We present simulations of the accretion of a massive planet or brown dwarf by an AGB star. In our scenario, close planets will be engulfed by the star, spiral-in and be dissipated in the ``accretion region&#39;&#39; located at the bottom of the convective envelope of the star. The deposition of mass and chemical elements in this region will release a large a

A. A. Starobinsky

Two extensions of ideas lying in the basis of the inflationary scenario of the early Universe and their effect on the large scale structure of the present-day Universe are discussed. The first of them is the possibility of fast phase transitions in physical fields other than an inflaton scalar field during inflation and nor far from the end of it. This resul

Annette Ferguson, Rosemary Wyse, Jay Gallagher, Deidre Hunter

We present deep Halpha images of three nearby late-type spiral galaxies (NGC628, NGC1058 and NGC6946), which reveal the presence of HII regions out to, and beyond, two optical radii (defined by the 25th B-band isophote). The outermost HII regions appear small, faint and isolated, compared to their inner disk counterparts, and are distributed in organized spi

Piero Madau

Through a combination of deep wide-field imaging and multi-object spectroscopy, the Next Generation Space Telescope will be able to chart with unprecedented accuracy the evolution of cosmic structures after the `dark ages&#39; (z<5), when galaxies are thought to assemble and form the bulk of their stars. In this talk I will discuss how NGST observations migh

Michael S. Turner

A better understanding of the formation of large-scale structure in the Universe is arguably the most pressing question in cosmology. The most compelling and promising theoretical paradigm, Inflation + Cold Dark Matter, holds that the density inhomogeneities that seeded the formation of structure in the Universe originated from quantum fluctuations arising d

E. C. Ford, M. van der Klis

We study the timing properties of the low mass X-ray binary 4U 1728-34 using recently released data from the Rossi X-Ray Timing Explorer. This binary, like many others with accreting neutron stars, is known to exhibit strong quasi-periodic oscillations (QPOs) of its X-ray flux near 1 kHz. In addition to the kilohertz QPOs, the Fourier power spectra show a br

Thierry J. -L. Courvoisier

We review the observed properties of the bright quasar 3C~273 and discuss the implications of these observations for the emission processes and in view of gaining a more global understanding of the object. Continuum and line emission are discussed. The emission from the radio domain to gamma rays are reviewed. Emphasis is given to variability studies across

P. Papaderos, K. J. Fricke

We discuss the X-ray properties of the interacting system Arp 284, consisting of the active nuclear starburst galaxy NGC 7714 and its post-starburst companion NGC 7715. A morphological signature of the interaction, thought to have started <100 Myr ago, is an asymmetric stellar ring dominating the intensity profile of NGC 7714 in the inner disk (~ 2 exponenti

H. S. Stockman, D. Fixsen, R. Hanisch, J. C. Mather

The NASA Yardstick design for the Integrated Science Instrument Module (ISIM) utilizes 64 1k x 1k InSb imagers. Since multiple readouts per image are required to remove cosmic ray events and to reduce the readout noise, the implied downlink rates can approach 0.7 Tbytes per day. These would exceed the downlink capabilities of RF links from L2 or more distant

M. Carena, S. Mrenna, C. E. M. Wagner

The Higgs sector of the minimal supersymmetric standard model (MSSM) consists of five physical Higgs bosons, which offer a variety of channels for their experimental search. The present study aims to further our understanding of the Tevatron reach for MSSM Higgs bosons, addressing relevant theoretical issues related to the SUSY parameter space, with special

R. J. Marshall, G. H. C. New, K. Burnett, S. Choi

A straight forward numerical technique, based on the Gross-Pitaevskii equation, is used to generate a self-consistent description of thermally-excited states of a dilute boson gas. The process of evaporative cooling is then modelled by following the time evolution of the system using the same equation. It is shown that the subsequent rethermalisation of the

A. Abd El-Hady, Jusak Tandean, G. Valencia

We study the |Delta I|=3/2 amplitudes of hyperon non-leptonic decays of the form B->B&#39;+pi in the context of chiral perturbation theory. The lowest-order predictions are determined in terms of only one unknown parameter and are consistent within errors with current data. We investigate the theoretical uncertainty of these predictions by calculating the le

Viviane M de Oliveira, J F Fontanari

The thermodynamics of the infinite-range Ising spin glass with p-spin interactions in the presence of an external magnetic field h is investigated analytically using the replica method. We give emphasis to the analysis of the transition between the replica symmetric and the one-step replica symmetry breaking regimes. In particular, we derive analytical condi

Pijush K. Ghosh, Avinash Khare

We establish a simple algebraic relationship between the energy eigenstates of the rational Calogero-Sutherland model with harmonic oscillator and Coulomb-like potentials. We show that there is an underlying SU(1,1) algebra in both of these models which plays a crucial role in such an identification. Further, we show that our analysis is in fact valid for an

Jorma Louko, Donald Marolf

In the context of the conjectured AdS-CFT correspondence of string theory, we consider a class of asymptotically Anti-de Sitter black holes whose conformal boundary consists of a single connected component, identical to the conformal boundary of Anti-de Sitter space. In a simplified model of the boundary theory, we find that the boundary state to which the b

Michael Gutperle, Yuji Satoh

Boundary states corresponding to wrapped D-branes in Calabi-Yau compactifications of type II strings are discussed using Gepner models. In particular boundary conditions corresponding to D-0 branes and D-instantons in four dimensions are investigated. The boundary states constructed by Recknagel and Schomerus are analyzed in the light-cone gauge and the brok

Pawan Kumar, Sarbani Basu

The sense of line asymmetry of solar p-modes in the intensity power spectra is observed to be opposite of that seen in the velocity power spectra. Theoretical calculations provide a good understanding and fit to the observed velocity power spectra whereas the reverse sense of asymmetry in the intensity power spectrum has been poorly understood. We show that

Pawan Kumar, Sarbani Basu

The observed solar p-mode velocity power spectra are compared with theoretically calculated power spectra over a range of mode degree and frequency. The shape of the theoretical power spectra depends on the depth of acoustic sources responsible for the excitation of p-modes, and also on the multipole nature of the source. We vary the source depth to obtain t

B. Abbott

We search for physics beyond the standard model using events with a photon, two or more hadronic jets, and an apparent imbalance in transverse energy, in $p\bar{p}$ collisions at the Fermilab Tevatron at $\sqrt{s}=1.8$ TeV. Such events are predicted for production of supersymmetric particles. No excess is observed beyond expected background. For the paramete

G. Alexanian, E. F. Moreno

Using a novel approach to renormalization in the Hamiltonian formalism, we study the connection between asymptotic freedom and the renormalization group flow of the configuration space metric. It is argued that in asymptotically free theories the effective distance between configuration decreases as high momentum modes are integrated out.

Torsten A. Ensslin, Richard Lieu, Peter L. Biermann

The excess in extreme-ultraviolet (EUV) radiation and high energy X-rays (HEX) of Coma may be modeled by power law spectra. Their origin could be inverse Compton (IC) emission by relativistic electrons. The scattered photon fields can either be the CMB or the starlight of the galaxies within the cluster. If the EUV excess is due to CMB-IC, a strongly inhomog

Mohammad Kohandel, Mehran Kardar

We use a Langevin equation to examine the dynamics and fluctuations of a flux line (FL) in the presence of an {\it alternating longitudinal current} $J_{\parallel}(ω)$. The magnus and dissipative forces are equated to those resulting from line tension, confinement in a harmonic cage by neighboring FLs, parallel current, and noise. The resulting mean-square F

Ravi K. Sheth, Gerard Lemson

In hierarchical models of gravitational clustering, virialized haloes are biased tracers of the matter distribution. As discussed by Mo & White (1996), this bias is nonlinear and stochastic. They developed a model which allows one to write down analytic expressions for the mean of the bias relation, in the initial Lagrangian, and the evolved, Eulerian spaces

E. Cuevas

The effect of Coulomb and short-range interactions on the spectral properties of two-dimensional disordered systems with two spinless fermions is investigated by numerical scaling techniques. The size independent universality of the critical nearest level-spacing distribution $P(s)$ allows one to find a delocalization transition at a critical disorder $W_{\r

Samuel De Toro Arias, Xavier Waintal, Jean-Louis Pichard

The interplay between the quantum interferences responsible for one particle localization over a length L_1, and the partial dephasing induced by a local interaction of strength U with another particle leading to partial delocalization over a length L_2 > L_1, is illustrated by a study of the motion of two particles put close to each other at the initial tim

A. Arhrib, G. Moultaka

One loop radiative corrections to $e^+e^-\to H^+ H^-$ are considered at future linear collider energies, in the general type II Two Higgs Doublet Model (THDM) and in the Minimal Supersymmetric Standard Model-like (MSSM) Higgs sector. To make the comparison between THDM and MSSM tractable, we have introduced a quasi-SUSY parameterization which preserves all t

Dragan Huterer, Michael S. Turner

Distance measurements to Type Ia supernovae (SNe Ia) indicate that the Universe is accelerating and that two-thirds of the critical energy density exists in a dark-energy component with negative pressure. Distance measurements to SNe Ia can be used to distinguish between different possibilities for the dark energy, and if it is an evolving scalar field, to r

L. Vaidman

Three arguments based on the Greenberger-Horne-Zeilinger (GHZ) proof of the nonexistence of local hidden variables are presented. The first is a description of a simple game which a team that uses the GHZ method will always win. The second uses counterfactuals in an attempt to show that quantum theory is nonlocal in a stronger sense than is implied by the no

S. I. Bityukov, N. V. Krasnikov

We propose a method to estimate the probability of new physics discovery in future high energy physics experiments. Physics simulation gives both the average numbers $<N_b>$ of background and $<N_s>$ of signal events. We find that the proper definition of the significance for $<N_b>, <N_s> \gg 1$ is $S_{12} = \sqrt{<N_s>+<N_b>} - \sqrt{<N_b>}$ in comparison

Kai Hencken, Dirk Trautmann, Gerhard Baur

We present a calculation of higher order effects for the impact parameter dependent probability for single and multiple electron-positron pairs in (peripheral) relativistic heavy ion collisions. Also total cross sections are given for SPS and RHIC energies. We make use of the expression derived recently by several groups where the summation of all higher ord