July 1997 arXiv papers — page 14

V. Krakoviack, C. Alba-Simionesco, M. Krauzman

By using simple mode coupling equations, we investigate the depolarized light scattering spectra of two so-called "fragile" glassforming liquids, salol (phenylsalicylate) and CKN (Ca_{0.4}K_{0.6}(NO_3)_{1.4}), measured by Cummins and coworkers. Nonlinear integrodifferential equations for the time evolution of the density-fluctuations autocorrelation

Byungnam Kahng, Kwangho Park, Jinhee Park

We present a self-organized stochastic model for the dynamics of a single flux line in random media. The dynamics for the flux line in the longitudinal and the transversal direction to an averaged moving direction are coupled to each other. The roughness exponents of the flux line are measured for each direction, which are close to $α_{\parallel}\approx 0.63

H. Jeong, B. Kahng, D. E. Wolf

We reexamine the density of two dimensional islands in the submonolayer regime of a homoepitaxially growing surface using the coarse grained Monte Carlo simulation with random sequential updating rather than parallel updating. It turns out that the power law dependence of the density of islands on the deposition rate agrees much better with the theoretical p

J. Robert Buchler

We introduce the reader to the "global flow reconstruction method". The purpose of the method is to see if a given temporal sequence has been generated by a low dimensional dynamics, and to determine that dimension and other properties of the dynamics. The method is shown to work very well on the well known Roessler system. An application of the meth

J. R. Buchler, Z. Kollath, T. Serre, J. Mattei

It is first shown that the observational light curve data of R Scuti, a star of the RV Tau type, is not multi-periodic, and that it cannot have been generated by a linear stochastic (AR) process. By default, the signal must be a manifestation of deterministic chaos. We use a novel nonlinear time-series analysis, the global flow reconstruction technique, to p

Evan S. Scannapieco, Pedro G. Ferreira

We propose a new method for constraining a primordial homogeneous magnetic field with the cosmic microwave background. Such a field will induce an observable parity odd cross correlation between the polarization anisotropy and the temperature anisotropy by Faraday rotation. We analyze the necessary experimental features to match, and improve, current constra

Henry E. Kandrup

Time-independent Hamiltonian flows are viewed as geodesic flows in a curved manifold, so that the onset of chaos hinges on properties of the curvature two-form entering into the Jacobi equation. Attention focuses on ensembles of orbit segments evolved in 2-D potentials, examining how various orbital properties correlate with the mean value and dispersion, <K

Michael Harris, Jian Wang, Vigdor L. Teplitz

Recently, Dicus and Repko computed nu gamma --> nu gamma gamma for energies below the threshold for e^{+}e^{-} pair production. They found across section on the order of 10^{-52} omega ^{gamma} with gamma =10, where omega is the CMS energy of one of the initial particles in MeV. Cross sections for the crossed processes are the same to factors of order one. T

Y. Dabrowski, M. P. Hobson, A. N. Lasenby, C. Doran

We present a new model for the formation of spherically symmetric clusters in an expanding Universe. Both the Universe and the collapsing cluster are governed by the same pressure less fluid equations for which a uniform initial density profile is assumed. A simple perturbation imposed on the initial velocity field gives rise to an over-density which closely

Peter A. Milne, Lih-Sin The, Mark D. Leising

At times later than 200 days, Type Ia SN light curves are dominated by the kinetic energy deposition from positrons created in the decay of $^{56}$Co. In this paper, the transport of positrons after emission are simulated, for deflagration and delayed detonation models, assuming various configurations of the magnetic field. We find the light curve due to pos

G. E. Allen, J. W. Keohane, E. V. Gotthelf, R. Petre

We present the 2-60 keV spectrum of the supernova remnant Cassiopeia A measured using the Proportional Counter Array and the High Energy X-ray Timing Experiment on the Rossi X-ray Timing Explorer satellite. In addition to the previously reported strong emission-line features produced by thermal plasmas, the broad-band spectrum has a high-energy &#34;tail&#34

Martin Zwaan, Frank Briggs, David Sprayberry, Ertu Sorar

The HI mass function (HIMF) for galaxies in the local universe is constructed from the results of the Arecibo HI Strip Survey, a blind extragalactic survey in the 21cm line. The survey consists of two strips covering in total 65 square degrees of sky, with a depth of cz = 7400 km/s and was optimized to detect column densities of neutral gas N_HI > 10^18 cm^-

J. C. Niemeyer, A. R. Kerstein

Gibson scaling and related properties of flame-surface geometry in turbulent premixed combustion are demonstrated using a novel computational model, Deterministic Turbulent Mixing (DTM). In DTM, turbulent advection is represented by a sequence of maps applied to the computational domain. The structure of the mapping sequence incorporates pertinent scaling pr

R. G. Gratton, F. Fusi Pecci, E. Carretta, G. Clementini

High precision trigonometric parallaxes from the HIPPARCOS satellite and accurate metal abundances ([Fe/H], [O/Fe], and [alpha/Fe]) from high resolution spectroscopy for about 30 local subdwarfs have been used to derive distances and ages for a carefully selected sample of nine globular clusters. We find that HIPPARCOS parallaxes are smaller than the corresp

Brian A. Vaughan, Shunji Kitamoto

We present X-ray light curves and energy spectra for the persistent accreting pulsars 4U 1626-67 and GX 301-2 measured by the All-Sky Monitor (ASM) on Ginga from 1987 March - 1991 October. We compare these with simultaneous and near simultaneous measurements of spin frequency and flux by other instruments, principally the Burst and Transient Source Experimen

Martin Markl

The aim of the paper is to give an `elementary&#39; introduction to the theory of modules over operads and discuss three prominent examples of these objects - simplex, associahedron (= the Stasheff polyhedron) and cyclohedron (= the compactification of the space of configurations of points on the circle). Keywords: (right) module over an operad, module assoc

P. M. H. Wilson

This manuscript from August 1995 (revised February 1996) studies the Kaehler cone of Calabi-Yau threefolds via symplectic methods. For instance, it is shown that if two Calabi-Yau threefolds are general in complex moduli and are symplectic deformations of each other, then their Kaehler cones are the same. The results are generalizations of those in the autho

J. Heintz, G. Matera, L. M. Pardo, R. Wachenchauzer

This paper is devoted to the complexity analysis of a particular property, called &#34;algebraic robustness&#34; owned by all known symbolic methods of parametric polynomial equation solving (geometric elimination). It is shown that any parametric elimination procedure which owns this property must neccessarily have an exponential sequential time complexity.

Jesper Funch Thomsen

Let G be a linear algebraic group, P be a parabolic subgroup of G and βbe a cycle of dimension 1 in the Chow group of the quotient G/P. Using geometric arguments and Borel&#39;s fixed point theorem, we prove that the moduli space \bar{M}_{0,n}(G/P, β) of n-pointed genus 0 stable maps representing βis irreducible.

D. P. Kirilova, M. V. Chizhov

We study the nonresonant oscillations between left-handed electron neutrinos nu_e and nonthermalized sterile neutrinos nu_s in the early Universe plasma. The case when nu_s do not thermalize till 2 MeV and the oscillations become effective after nu_e decoupling is discussed. The evolution of neutrino ensembles was described numerically by integrating the kin

Rabindra N. Mohapatra, Andrija Rasin, Goran Senjanovic

We systematically study the connection between P, C and strong CP in the context of both non-supersymmetric and supersymmetric left-right theories. We find that the solution to the strong CP problem requires both supersymmetry and parity breaking scales to be around the weak scale.

Xiangdong Shi, Michael S. Turner

There are irreducible differences between the Hubble constant measured locally and the global value. They are due to density perturbations and finite sample volume (cosmic variance) and finite number of objects in the sample (sampling variance). We quantify these differences for a suite of COBE-normalized CDM models that are consistent with the observed larg

O. B. Zaslavskii

Dilaton black holes with a pure electric charge are considered in a framework of a grand canonical ensemble near the extreme state. It is shown that there exists such a subset of boundary data that the Hawking temperature smoothly goes to zero to an infinite value of a horizon radius but the horizon area and entropy are finite and differ from zero. In string

David W. Chappell, John Scalo

Multifractal scaling (MFS) refers to structures that can be described as a collection of interwoven fractal subsets which exhibit power-law spatial scaling behavior with a range of scaling exponents (concentration, or singularity, strengths) and dimensions. The existence of MFS implies an underlying multiplicative (or hierarchical, or cascade) process. Panor

C. S. Lam

This paper contains an implicit assumption that the summand in eq. (4.2) for different $n$&#39;s commute. This paper should be replaced by hep-th/9804181 where this assumption is removedand the result generalized.

Roy Maartens, Josep Triginer

We investigate cosmological density perturbations in a covariant and gauge-invariant formalism, incorporating relativistic causal thermodynamics to give a self-consistent description. The gradient of density inhomogeneities splits covariantly into a scalar part, equivalent to the usual density perturbations, a rotational vector part that is determined by the

I. Jack, D. R. T. Jones

We discuss issues that arise in the regularisation of supersymmetric theories. (To appear in the book `Perspectives on Supersymmetry&#39;, World Scientific, Editor G. Kane.)

V. Privman, I. D. Vagner, G. Kventsel

We describe a quantum information processor (quantum computer) based on the hyperfine interactions between the conduction electrons and nuclear spins embedded in a two-dimensional electron system in the quantum-Hall regime. Nuclear spins can be controlled individually by electromagnetic pulses. Their interactions, which are of the spin-exchange type, can be

Maria Gorelik

The prime spectra of two families of algebras, $S^w$ and $\check{S}^w$, $w\in W,$ indexed by the Weyl group $W$ of a semisimple finitely dimensional are studied. The algebras $S^w$ have been introduced by A.~Joseph; they are $q$-analogues of the algebras of regular functions on $w$-translates of the open Bruhat cell of a semisimple Lie group $G$ correspondin

Martin Gremm

We analyze the low energy behavior of N=1 supersymmetric gauge theories with SU(N_c) x SU(N_c) gauge group and a Landau-Ginzburg type superpotential. These theories contain fundamentals transforming under one of the gauge groups as well as bifundamental matter which transforms as a fundamentals under each. We obtain the parametrization of the gauge coupling

Stefano Mancini, Paolo Tombesi, Vladimir I. Man&#39;ko

We discuss the problem of finding &#34;marginal&#34; distributions within different tomographic approaches to quantum state measurement, and we establish analytical connections among them.

H. Hayakawa, K. Nakanishi

Traffic jam in an optimal velocity model with the backward reference function is analyzed. An analytic scaling solution is presented near the critical point of the phase separation. The validity of the solution has been confirmed from the comparison with the simulation of the model.

O. Aharony, M. Berkooz, S. Kachru, N. Seiberg

We propose descriptions of interacting (2,0) supersymmetric theories without gravity in six dimensions in the infinite momentum frame. They are based on the large $N$ limit of quantum mechanics or 1+1 dimensional field theories on the moduli space of $N$ instantons in $\IR^4$.

H. Tochimura, H-T. Sato

We illustrate the phase structure of a deformed two-dimensional Gross-Neveu model which is defined by undeformed field contents plus deformed Pauli matrices. This deformation is based on two motives to find a more general polymer model and to estimate how $q$-deformed field theory affects on its effective potential. There found some regions where chiral symm

Heinrich Saller

Quantum mechanical operators and quantum fields are interpreted as realizations of timespace manifolds. Such causal manifolds are parametrized by the classes of the positive unitary operations in all complex operations, i.e. by the homogenous spaces $\D(n)=\GL(\C^n_\R)/\U(n)$ with $n=1$ for mechanics and $n=2$ for relativistic fields. The rank $n$ gives the

Wang-Chang Su

We suggest an alternative approach to deconfine N =1 SU(N) supersymmetric gauge theory with a symmetric tensor, fundamentals, anti-fundamentals, and no superpotential. It is found that although the dual prescription derived by this new method of deconfinement is different from that by the original method, both dual prescriptions are connected by duality tran

L. E. Ibanez, A. M. Uranga

We review the structure $D=6, N=1$ string vacua with emphasis on the different connections due to T-dualities and S-dualities. The topics discussed include: Anomaly cancellation; K3 and orbifold $D=6, N=1$ heterotic compactifications; T-dualities between $E_8\times E_8$ and $Spin(32)/Z_2$ heterotic vacua; non-perturbative heterotic vacua and small instantons

G. Juettner, A. Kluemper, J. Suzuki

Functional relations among the fusion hierarchy of quantum transfer matrices give a novel derivation of the TBA equations, namely without string hypothesis. This is demonstrated for two important models of 1D highly correlated electron systems, the supersymmetric $t-J$ model and the supersymmetric extended Hubbard model. As a consequence, &#34;the excited st

Carmen Molina-Paris, Matt Visser

In this paper we take a deeper look at the technically elementary but physically robust viewpoint in which the Casimir energy in dielectric media is interpreted as the change in the total zero point energy of the electromagnetic vacuum summed over all states. Extending results presented in previous papers [hep-th/9609195; hep-th/9702007] we approximate the s

L. Lusanna, P. Valtancoli

The complete, missing, Hamiltonian treatment of the standard SU(3)xSU(2)xU(1) model with Grassmann-valued fermion fields in the Higgs phase is given. We bypass the complications of the Hamiltonian theory in the Higgs phase, resulting from the spontaneous symmetry breaking with the Higgs mechanism, by studying the Hamiltonian formulation of the Higgs phase fo

Khazret Nirov, Mikhail Plyushchay

A phenomenon of classical quantization is discussed. This is revealed in the class of pseudoclassical gauge systems with nonlinear nilpotent constraints containing some free parameters. Variation of parameters does not change local (gauge) and discrete symmetries of the corresponding systems, but there are some special discrete values of them which give rise

S. Bar-Shalom, D. Atwood, A. Soni

Appreciable CP Asymmetries (~ 10%) can arise in the reaction e+ e- -> t bar-t Z already at TREE-LEVEL in models with two Higgs doublets. For a neutral Higgs particle, h, with a mass in the range 50 GeV < m_h < 400 GeV, it may be possible to detect a 2-3 sigma CP-odd effect in e+ e- -> t bar-t Z in ~ 1-2 years of running of a future high energy e+e- collider

M. G. Olsson

The definitions and properties of elastic and inelastic Isgur-Wise form factors are reviewed. The nature of the &#34;missing&#34; exclusive semi-leptonic decay fraction is identified. The role that completeness sum rules play in relating form factors, spectroscopy, and model building is outlined.

Yuval Grossman, Mihir P. Worah

We make a systematic analysis of the effects of new physics in the B decay amplitudes on the CP asymmetries in neutral B decays. Although these are expected to be smaller than new physics effects on the mixing amplitude, they are easier to probe in some cases. The effects of new contributions to the mixing amplitude are felt universally across all decay mode

J. Chyla, J. Cvach

Some aspects of extracting the information on the structure of virtual photons from jet production in ep and e^+e^- collisions are discussed.

Richard D. Ball, Giovanni Ridolfi, Guido Altarelli, Stefano Forte

We summarise the perturbative QCD analysis of the structure function data for g_1 from longitudinally polarized deep inelastic scattering from proton, deuteron and neutron targets, with particular emphasis on testing sum rules, determining helicity fractions, and extracting the strong coupling from both scaling violations and the Bjorken sum rule.

Monoranjan Guchait, D. P. Roy

The favoured R-parity violating SUSY scenarios for the anomalous HERA events correspond to top and charm squark production via the $λ&#39;_{131}$ and $λ&#39;_{121}$ couplings. In both cases the corresponding electronic branching fractions of the squarks are expected to be $\ll 1$. Consequently the canonical leptoquark signature is incapable of probing these

A. Di Giacomo, G. Paffuti

A detailed discussion is given of the disorder parameter for dual superconductivity of lattice gauge theories, introduced in a previous paper, and of its relation to other approaches. New lattice data are reported. Among other results, we find that the dual superconductivity of compact U(1) is type II.

CLEO Collaboration, R. Ammar et al

Using the CLEO detector at the Cornell Electron Storage Ring, we have made a measurement of R=sigma(e+e- ->hadrons)/sigma(e+e- ->mu+mu-) =3.56+/-0.01+/-0.07 at ECM=10.52 GeV. This implies a value for the strong coupling constant of alpha_s(10.52 GeV)=0.20+/-0.01+/-0.06, or alpha_s(M_Z)=0.13+/-0.005+/-0.03.

R. Brinkmann, I. Ginzburg, N. Holtkamp, G. Jikia

Linear colliders offer unique opportunities to study gamma-gamma (gg), gamma-electron (ge) interactions. Using the laser backscattering method one can obtain gg, ge colliding beams with an energy and luminosity comparable to that in e+e- collisions. This work is a part of the Conceptual Design of TESLA/SBLC linear colliders describing a second interaction re

Manuela Campanelli, Carlos O. Lousto

We show that the radial Teukolsky equation (in the frequency domain) with sources that extend to infinity has well-behaved solutions. To prove that, we follow Poisson approach to regularize the non-rotating hole, and extend it to the rotating case. To do so we use the Chandrasekhar transformation among the Teukolsky and Regge-Wheeler-like equations, and expr

V. Meden, P. Schmitteckert, Nic Shannon

We present a detailed numerical study of the orthogonality catastrophe exponent for a one-dimensional lattice model of spinless fermions with nearest neighbor interaction using the density matrix remormalization group algorithm. Keeping up to 1200 states per block we achieve a very great accuracy for the overlap which is needed to extract the orthogonality e

Kingshuk Majumdar, Jian Chen, Selman Hershfield

We have studied the Giant Magnetoresistance (GMR) for laterally confined multilayers, e.g., layers of wires, using the classical Boltzmann equation in the current-in-plane (CIP) geometry. For spin-independent specularity factors at the sides of the wires we find that the GMR due to bulk and surface scattering decreases with lateral confinement. The length sc

G. R. Facer, B. E. Kane, R. G. Clark, L. N. Pfeiffer

In GaAs/AlGaAs parabolic quantum wells, subbands are depopulated by a magnetic field in the well plane. A small additional perpendicular field induces Shubnikov-de-Haas (SdH) oscillations which we have used to determine the carrier density, effective mass, and lifetime, thoughout the two subband to one subband transition. The masses of carriers in the first

T. Hwa, D. Cule

We analyze the recently proposed &#34;pattern-matching&#34; phase of a Gaussian random heteropolymer adsorbed on a disordered substrate [S. Srebnik, A.K. Chakraborty and E.I. Shakhnovich, Phys. Rev. Lett. 77, 3157 (1996)]. By mapping the problem to that of a directed homopolymer in higher-dimensional random media, we show that the pattern-matching phase is a

J. Hohlfeld, E. Matthias, R. Knorren, K. -H. Bennemann

Ultrafast magnetization dynamics of nickel has been studied for different degrees of electronic excitation, using pump-probe second-harmonic generation with 150 fs/800 nm laser pulses of various fluences. Information about the electronic and magnetic response to laser irradiation is obtained from sums and differences of the SHG intensity for opposite magneti

Linda Fabbian, Francesco Sciortino, Filippo Thiery, Piero Tartaglia

We introduce a semi-schematic mode-coupling model to describe the slow dynamics in molecular liquids, retaining explicitly only the description of the center of mass degrees of freedom. Angular degrees of freedom are condensed in a q-vector independent coupling parameter. We compare the time and q-dependence of the density fluctuation correlators with numeri

V. M. Pudalov

We present a model that explains two phenomena, recently observed in high-mobility Si-MOS structures: (i) the strong enhancement of metallic conduction at low temperatures, T<2 K, and (ii) the occurrence of the metal-insulator transition in 2D electron system. Both effects are prescribed to the Coulomb and spin-orbit interaction; the latter is anomalously en

Yoshio Kuramoto, Noboru Fukushima

A dynamical effective medium theory is presented for quantum spins and higher multipoles such as quadrupole moments. The theory is a generalization of the spherical model approximation for the Ising model, and is accurate up to O(1/z_n) where z_n is the number of interacting neighbors. The polarization function is optimized under the condition that it be dia

Brett Kessler, Geoffrey Nunberg, Hinrich Schuetze

As the text databases available to users become larger and more heterogeneous, genre becomes increasingly important for computational linguistics as a complement to topical and structural principles of classification. We propose a theory of genres as bundles of facets, which correlate with various surface cues, and argue that genre detection based on surface

Peter H. Hauschildt, Steven N. Shore, Greg J. Schwarz, E. Baron

We present new detailed NLTE calculations for model atmospheres of novae during outburst. This fully self-consistent NLTE treatment for a number of model atoms includes 3922 NLTE levels and 47061 NLTE primary transitions. We discuss the implication of departures from LTE for the strengths of the lines in nova spectra. The new results show that our large set

Henry E. Kandrup

This talk provides a critical assessment of collisionless galactic dynamics, focusing on the interpretation and limitations of the collisionless Boltzmann equation and the physical mechanisms associated with collisionless relaxation. Numerical and theoretical arguments are presented to motivate the idea that the evolution of a system far from equilibrium sho

Nathan Roche, Stephen Eales, Steve Rawlings

We use $K-band imaging to investigate the angular size and morphology of 10 6C radio galaxies, at redshifts $1\leq z\leq 1.4$. Two appear to be undergoing mergers, another contains two intensity peaks aligned with the radio jets, while the other seven appear consistent with being normal ellipticals in the K-band. Intrinsic half-light radii are estimated from

Z. Kollath, J. R. Buchler, T. Serre, J. Mattei

The AAVSO lightcurve data of the irregularly pulsating star AC Herculis of the RV Tau class are analysed. The lightcurve is shown to be incompatible with a periodic, or even multiperiodic pulsation, even if allowance is made for evolution. Instead the best explanation is that the irregularly alternating cycles are a manifestation of low dimensional chaos. Th

M. Girardi, D. Fadda, E. Escalera, G. Giuricin

We analyze the internal structures of clusters A1689 and A2218 by applying a recent development of the method of wavelet analysis, which uses the complete information obtained from optical data, i.e. galaxy positions and redshifts. We find that both clusters show the presence of structures superimposed along the line of sight with different mean redshifts an

G. Fiorentini, M. Moretti, F. L. Villante

We propose to exploit the angular distribution of the positrons emitted in the inverse beta decay to extract a possible antineutrino signal from the Superkamiokande background. From the statistics collected in just 101.9 days one obtains a model independent upper bound on the antineutrino flux (for energy greater than 8.3 MeV) Phi < 9*10^4 cm^-2 s^-1 at the

Wei Cui, W. A. Heindl, J. H. Swank, D. M. Smith

We present the results from RXTE observations of a new X-ray transient, GRS 1737-31, near the Galactic center during an outburst. Over a span of two weeks, the source was seen to vary significantly on time scales down to a few seconds. The rapid flares in the light curves bear resemblance to those observed for Cygnus X-1, a well-known black hole candidate (B

E. Gaztanaga, F. Bernardeau

We study the domain of validity of Perturbation Theory (PT), by comparing its predictions for the reduced skewness, s_3, and kurtosis, s_4, of the projected cosmological density field, with the results of N-body simulations. We investigate models with different linear power spectra and consider as physical applications both angular galaxy catalogues and weak

O. Vilhu, J. Nevalainen, J. Poutanen, M. Gilfanov

Combined ASCA and SIGMA data of 1E1740.7-2942 during the standard state (September 1993 and 1994) were fitted with two-phase models (ISMBB/Poutanen at al. and ADAF/Narayan et al.). In ISMBB&#39;s, the radius of the spherical hot (Te = 150 - 200 KeV) corona lies between 200 - 250 km where it joins the classical inner disc. The disc radiates 40 per cent of the

H. J. Mo, Shude Mao, Simon D. M. White

We study the population of galactic disks expected in current hierarchical clustering models for structure formation. A rotationally supported disk with exponential surface density profile is assumed to form with a mass and angular momentum which are fixed fractions of those of its surrounding dark halo. We assume that haloes respond adiabatically to disk fo

Kimiyo Fukasaku, Takehisa Fujita

We examine the calculation of the solar neutrino flux based on the standard solar model (SSM). It is found that the solar neutrino data (KAMIOKANDE experiment) can be well described by the SSM with careful employment of nuclear data of $^7Be (p,γ) ^{8} B$. The main point is that the simple-minded product ansatz of Coulomb plus nuclear parts should have a few

Barry F. Madore, Wendy L. Freedman

Hipparcos parallaxes have recently become available for a sample of Galactic Cepheids, and we have used these new distances to calibrate the Cepheid period-luminosity (PL) relation at six wavelengths (BVIJHK). Comparing these calibrations with previously published multiwavelength PL relations we find agreement to within 0.07 +/- 0.14 mag, or 4 +/- 7% in dist

J. H. J. de Bruijne, R. Hoogerwerf, A. G. A. Brown, L. A. Aguilar

We present a new procedure for the identification of moving groups. It is a combination of two independent member selection methods. One is a modern implementation of a classical convergent point method for proper motion data. The other objectively identifies moving groups in velocity space using proper motions and parallaxes. We briefly describe both method

P. T. de Zeeuw, A. G. A. Brown, J. H. J. de Bruijne, R. Hoogerwerf

We present the first results of a comprehensive census of the stellar content of the nearby OB associations based on Hipparcos positions, proper motions and parallaxes for 12842 candidate member stars distributed over 21 fields on the sky. We use a new method to identify moving groups in these fields (see de Bruijne et al., these proceedings). Previously, as

R. Hoogerwerf, J. H. J. de Bruijne, A. G. A. Brown, J. Lub

We have developed a new procedure to identify moving groups, and have applied it to carry out a census of the nearby OB associations based on Hipparcos parallaxes and proper motions (see de Bruijne et al. and de Zeeuw et al. elsewhere in this volume). Here we present three illustrative cases. For $α$ Persei our method allows us to refine the bright end of th

E. E. Narimanov, A. Douglas Stone, G. S. Boebinger

We develop a quantitative semiclassical formula for the resonant tunneling current through a quantum well in a tilted magnetic field. It is shown that the current depends only on periodic orbits within the quantum well. The theory explains the puzzling evolution of the tunneling spectra near a tilt angle of $30^{\circ}$ as arising from an exchange bifurcatio

Eue Jin Jeong

The unexpected dynamic shift of the center of mass for a rotating hemisphere is shown to produce the general relativistic dipole field in the macroscopic scale. This prompts us the question of what might be its cosmological implications. The uniformly rotating sphere has the effect of the latitude dependent mass density distribution as reported by Bass and P

A. G. Cohen, A. De Rujula, S. L. Glashow

We ask whether the universe can be a patchwork consisting of distinct regions of matter and antimatter. We demonstrate that, after recombination, it is impossible to avoid annihilation near regional boundaries. We study the dynamics of this process to estimate two of its signatures: a contribution to the cosmic diffuse gamma-ray background and a distortion o

M. J. Black, B. W. Alphenaar, H. Ahmed

We observe a series of discontinuities in the above gap current/voltage characteristics of highly transmissive Nb/Si superconductor/semiconductor interfaces. The bias at which each switch occurs decreases in quantized steps as a function of temperature and magnetic field. The observed step-size is the same for both dependencies. We propose that the steps cor

L. -S. The, M. D. Leising, D. H. Hartmann, J. D. Kurfess

We report the results of extracting the hard X-ray continuum spectrum of Cas A SNR from RXTE/PCA Target of Opportunity (TOO) observations and CGRO/OSSE observations. The data can rule out the single thermal bremsstrahlung model for Cas A continuum between 2 and 150 keV. The single power law model gives a mediocre fit (~5%) to the data with a power-law index,

Marcos Rosenbaum, Alexander Turbiner, Antonio Capella

It is shown that the 3-body trigonometric G_2 integrable system is exactly-solvable. If the configuration space is parametrized by certain symmetric functions of the coordinates then, for arbitrary values of the coupling constants, the Hamiltonian can be expressed as a quadratic polynomial in the generators of some Lie algebra of differential operators in a

Robert Friedman, John W. Morgan, Edward Witten

Let $G$ be a simple and simply connected complex Lie group. We discuss the moduli space of holomorphic semistable principal $G$ bundles over an elliptic curve $E$. In particular we give a new proof of a theorem of Looijenga and Bernshtein-Shvartsman, that the moduli space is a weighted projective space. The method of proof is to study the deformations of cer

J. R. Chapman, N. F. Johnson, V. N. Nicopoulos

The negatively charged quasi-two-dimensional exciton ($X^-$) is studied numerically in the presence of a uniform B-field and various in-plane confinements. The corresponding photoluminescence (PL) spectra, including shakeup processes, are calculated. These calculations provide a quantitative explanation of recent experimental PL spectra. The photoluminescenc

J. R. Buchler, P. A. Yecko, Z. Kollath

Strange modes have been found in the radial spectrum of many luminous stars, most recently in Cepheids and RR Lyrae. We show that there is nothing strange about these modes -- they must exist even in the adiabatic limit. With a change of variables and without approximation the adiabatic linear pulsation equation is reduced to a Schroedinger equation in which

M. Ulmke, P. Denteneer, R. Scalettar, G. Zimanyi

The two-dimensional Hubbard model with a bimodal distribution of on-site interactions, P(U_i) = (1-f)δ(U_i-U) + fδ(U_i), is studied using a finite temperature quantum Monte Carlo technique and dynamical mean-field theory. We find long range antiferromagnetic order off half-filling is stabilized by the disorder, due to localization of the dopants on the U=0 s

J. Fuchs, C. Schweigert

By exploring the description of chiral blocks in terms of co-invariants, a derivation of the Verlinde formula for WZW models is obtained which is entirely based on the representation theory of affine Lie algebras. In contrast to existing proofs of the Verlinde formula, this approach works universally for all untwisted affine Lie algebras. As a by-product we

A. Datta X. -G. He, S. Pakvasa

We consider the effective Hamiltonian of four quark operators in the Standard Model in the exclusive and quasi-inclusive decays of the type $B\to K^{(*)} η^{\prime}$, $B\to η&#39; X_s$, where $X_s$ contains a single Kaon. Working in the factorization assumption we find that the four quark operators can account for the recently measured exclusive decays $B\to

Dario Grasso, Antonio Riotto

In this Letter we reanalyse the question of the origin of magnetic fields during the electroweak phase transition. We show that their formation is intimately connected to some semiclassical configurations of the gauge fields, such as electroweak Z-strings and W-condensates. We describe the formation of these semiclassical configurations during a first order

Mikhail V. Altaisky

Most of dynamic systems which exhibit chaotic behavior are also known to posses self-similarity and manifest strong fluctuations of all possible scales.The meaning of this terms is not always same. In present note we make an attempt to formulate the problem in the framework of functional analysis. The statistical hydrodynamics is taken as a vivid physical ex

Z. Popowicz

We present two different Lax operators for a manifestly N=2 supersymmetric extension of &#34;a=-2&#34; Boussinesq hierarchy . The first is the supersymmetric generalization of the Lax operator of the Modified KdV equation. The second is the generalization of the supersymmetric Lax operator of the N=2 supersymmetric a=-2 KdV system. The gauge transformation o

A. Kawai, T. Fukushige, M. Taiji, J. Makino

We developed a PCI interface for GRAPE systems. GRAPE(GRAvity piPE) is a special-purpose computer for gravitational N-body simulations. A GRAPE system consists of GRAPE processor boards and a host computer. GRAPE processors perform the calculation of gravitational forces between particles. The host computer performs the rest of calculations. The newest of GR

V. L. Vereschagin

Problem of asymptotic description for global solutions to the six Painleve equations was investigated. Elliptic anzatzes and appropriate modulation equations were written out.

Gerhard C. Hegerfeldt

In order to check finite propagation speed Fermi, in 1932, had considered two atoms A and B separated by some distance R. At time t=0, A is in an excited state, B in its ground state, and no photons are present. Fermi&#39;s idea was to calculate the excitation probability of B. In a model-independent way and with minimal assumptions - Hilbert space and posit

C. Dong, R. L. Griess, G. Hoehn

For a simple vertex operator algebra whose Virasoro element is a sum of commutative Virasoro elements of central charge 1/2, two codes are introduced and studied. It is proved that such vertex operator algebras are rational. For lattice vertex operator algebras and related ones, decompositions into direct sums of irreducible modules for the product of the Vi

V. Ovsienko, C. Roger

We study deformations of the standard embedding of the Lie algebra $\Vect(S^1)$ of smooth vector fields on the circle, into the Lie algebra of functions on the cotangent bundle $T^*S^1$ (with respect to the Poisson bracket). We consider two analogous but different problems: (a) formal deformations of the standard embedding of $\Vect(S^1)$ into the Lie algebr

Bao-An Li, Che Ming Ko, Wolfgang Bauer

In nuclear collisions induced by stable or radioactive neutron-rich nuclei a transient state of nuclear matter with an appreciable isospin asymmetry as well as thermal and compressional excitation can be created. This offers the possibility to study the properties of nuclear matter in the region between symmetric nuclear matter and pure neutron matter. In th

R. K. Gupta, M. K. Sharma, S. Singh, R. Nouicer

Calculations for fission and cluster decay of $^{76}Sr$ are presented for this nucleus to be in its ground-state or formed as an excited compound system in heavy-ion reactions. The predicted mass distribution, for the dynamical collective mass transfer process assumed for fission of $^{76}Sr$, is clearly asymmetric, favouring $α$-nuclei. Cluster decay is stu

Hiroyuki Yabu, Satoshi Nozawa, Toru Suzuki

The effective field theory including the dissipative effect is developed based on the Caldeira-Leggett theory at the classical level. After the integration of the small field fluctuations considered as the field radiation, the integro-differential field equation is given and shown to include the dissipative effects. In that derivation, special cares should b

Robert Finn, John McCuan

We consider a capillary drop that contacts several planar bounding walls so as to produce singularities (vertices) in the boundary of its free surface. It is shown under various conditions that when the number of vertices is less than or equal to three, then the free surface must be a portion of a sphere. These results extend the classical theorem of H. Hopf

Michelle L. Wachs

We consider a simplicial complex generaliztion of a result of Billera and Meyers that every nonshellable poset contains the smallest nonshellable poset as an induced subposet. We prove that every nonshellable $2$-dimensional simplicial complex contains a nonshellable induced subcomplex with less than $8$ vertices. We also establish CL-shellability of interva