July 2002 arXiv papers — page 12

Jozef Strecka, Michal Jascur

The mixed spin-1/2 and spin-1 Ising model in the presence of an anisotropic crystalline field is treated exactly within the framework of an extended star-triangle mapping transformation. The exact results for the phase diagrams, magnetization, internal energy and specific heat are derived and discussed in detail. The relevant mapping suggests that an isotrop

Jozef Strecka, Hana Cencarikova, Michal Jascur

Magnetic properties of the 1D mixed spin-1/2 and spin-S (S >1/2) transverse Ising model in the presence of an external longitudinal magnetic field are calculated exactly by the use of the generalised decoration-iteration mapping transformation. By assuming that only the spin-S atoms do interact with the transverse field the exact results for the Gibbs free e

Jean Schmittbuhl, Alex Hansen, G. George Batrouni

We show that the roughness exponent zeta of an in-plane crack front slowly propagating along a heterogeneous interface embeded in a elastic body, is in full agreement with a correlated percolation problem in a linear gradient. We obtain zeta=nu/(1+nu) where nu is the correlation length critical exponent. We develop an elastic brittle model based on both the

Hai Wang, H. Cheng, N. Garcia

This paper reports ballistic magnetoresistance values over 4000% measured in electrodeposited Ni-Ni nanocontacts with T geometry previously developed . Over the time, after several magnetic field cycles, the ballistic magnetoresistance relaxed to a 400%. While that the magnetoreistance of a contact could rise indefinitely; relaxtion and reproducibility are,

Michel Peyrard, Isabelle Daumont

We study a one-dimensional discrete analog of the von Karman flow, widely investigated in turbulence. A lattice of anharmonic oscillators is excited by both ends in order to create a large scale structure in a highly nonlinear medium, in the presence of a dissipative term similar to the viscous term in a fluid. This system shows a striking similarity with a

N. Gov, A. G. Zilman, S. Safran

We analyze both the static and dynamic fluctuation spectrum of the red-blood cell in a unified manner, using a simple model of the composite membrane. In this model, the two-dimensional spectrin network that forms the cytoskeleton is treated as a rigid shell which is located at some constant average separation from the lipid bilayer. The cytoskeleton thereby

Alexander O. Gogolin, Andrei Komnik

We analyse non-equilibrium transport properties of a single-state molecular quantum dot coupled to a local phonon and contacted by two electrodes. We derive the effective non-equilibrium (Keldysh) action for the phonon mode and study the structure of the saddle points, which turn out to be symmetric with respect to time inversion. Above a critical electron-p

T. Temesvari, C. De Dominicis

We use the generic replica symmetric cubic field-theory to study the transition of short range Ising spin glasses in a magnetic field around the upper critical dimension, d=6. A novel fixed-point is found, in addition to the well-known zero magnetic field fixed-point, from the application of the renormalization group. In the spin glass limit, n going to 0, t

Dominik Munzar, Todd Holden, Christian Bernhard

We present an extension of the c-axis tight-binding sum rule discussed by Chakravarty, Kee, and Abrahams [Phys. Rev. Lett. 82, 2366 (1999)] that applies to multilayer high-Tc cuprate superconductors (HTCS) and use it to estimate--from available infrared data--the change below Tc of the c-axis kinetic energy, Hc, in YBa2Cu3O(7-delta) (delta=0.45,0.25,0.07), B

Marek Cieplak, Trinh Xuan Hoang

Molecular dynamics simulations in simplified models allow one to study the scaling properties of folding times for many proteins together under a controlled setting. We consider three variants of the Go models with different contact potentials and demonstrate scaling described by power laws and no correlation with the relative contact order parameter. We dem

Qiang Gu

We present a perturbation theory for studying thermodynamic properties of the Kondo spin liquid phase of the half-filled Kondo lattice model. The grand partition function is derived to calculate chemical potential, spin and charge susceptibilities and specific heat. The treatment is applicable to the model with strong couplings in any dimensions (one, two an

Victor Kurasov

A simple method to get all main characteristics of nucleation process is proposed. The advantage of this method is an applicability to situations with non-linear behavior in time of effective external source of vapor. It is important because already existed objects of a new phase comsume vapor in non-linear manner and form an effective non-linear behavior of

Victor Kurasov

An expression for the free energy of embryo formation is constructed and analyzed. The Gibbs dividing surfaces method is used to attain a coincidence between Laplace formula for critical embryo and integral definitions of concenterations inside the embryo. A global structure of free energy is analyzed and some useful properties are extracted.

Vahé Petrosian

The discovery of hard X-rays from tops of flaring loops by the HXT of YOHKOH represents a significant progress in the understanding of solar flares. This report describes the properties of 20 limb flares observed by YOHKOH from October 1991 to August 1998, 15 of which show detectable impulsive looptop emission. Considering the finite dynamic range (about a d

Vahé Petrosian

Recent observations of excess radiation at extreme ultraviolet and hard X-ray energies straddling the well known thermal soft X-ray emission have provided new tools and puzzles for investigation of the acceleration of nonthermal particles in the intercluster medium of clusters of galaxies. It is shown that these radiations can be produced by the inverse Comp

Christopher L. Gerardy, Robert A. Fesen, Ken'ichi Nomoto, Keiichi Maeda

We present K-band (1.9 -- 2.5 micron) spectra of the Type Ic SN 2000ew observed with IRCS on the Subaru Telescope. These data show the first detection of carbon monoxide (CO) emission in a Type Ic supernova. The detection of CO in SN 2000ew provides further evidence that molecule formation may be a common occurrence in core-collapse supernova ejecta. The spe

Jason X. Prochaska, Emma Ryan-Weber, Lister Staveley-Smith

We examine the gas kinematics of the LMC revealed by the high spatial and velocity resolution HI data cube of the combined ATCA and Parkes telescope surveys. We adopt an approach designed to facilitate comparisons with quasar absorption line observations, in particular restricting our analysis to pointings with HI column density satisfying the damped Lya (DL

Michael C. Liu

We present some results from a systematic survey for disks around spectroscopically identified young brown dwarfs and very low mass stars. We find that ~75% of our sample show intrinsic IR excesses, indicative of circum(sub)stellar disks. The observed excesses are correlated with Halpha emission, consistent with a common disk accretion origin. Because the ex

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

We revisit the problem of magnetic field generation in accretion flows onto black holes owing to the excess radiation force on electrons. This excess force may arise from the Poynting-Robertson effect. Instead of a recent claim of the generation of dynamically important magnetic fields, we establish the validity of earlier results from 1977 which show only s

Jurgen Knodlseder, Jean-Pierre Roques

With the launch of ESA's INTEGRAL satellite in october 2002, a gamma-ray observatory will become available to the scientific community that combines imaging and spectroscopic capacities in the 20 keV to 10 MeV energy range. In this paper, we summarise the science prospects of the SPI spectrometer aboard INTEGRAL which provides unprecedented spectral reso

R. T. Edwards, B. W. Stappers

The basic form of drifting sub-pulses is that of a periodicity whose phase depends (approximately linearly) on both pulse longitude and pulse number. As such, we argue that the two-dimensional Fourier transform of the longitude-time data (called the Two-Dimensional Fluctuation Spectrum; 2DFS) presents an ideal basis for studies of this phenomenon. We examine

Eric J. Lentz, E. Baron, Peter H. Hauschildt, David Branch

The presence of a small amount of hydrogen is expected in most single degenerate scenarios for producing a Type Ia supernova (SN Ia). While hydrogen may be detected in very early high resolution optical spectra, in early radio spectra, and in X-ray spectra, here we examine the possibility of detecting hydrogen in early low resolution spectra such as those th

Roelof Bottema, Jose L. G. Pestana, Barry Rothberg, Robert H. Sanders

Rotation curves for four spiral galaxies with recently determined Cepheid-based distances are reconsidered in terms of modified Newtonian dynamics (MOND). For two of the objects, NGC 2403 and NGC 7331, the rotation curves predicted by MOND are compatible with the observed curves when these galaxies are taken to be at the Cepheid distance. For NGC 3198, the l

Hernan Muriel, Hernan Quintana, Leopoldo Infante, Diego G. Lambas

We report an analysis of the dynamical structure of clusters of galaxies from a survey of photometric and spectroscopic observations in the fields of southern Abell Clusters. We analyze the galaxy velocity field in extended regions up to 7 h^-1 Mpc from cluster centers and we estimate mean velocity dispersions and their radial dependence. Only one from a tot

Lydie Koch-Miramond, P'eter 'Abrah'am, Ya"el Fuchs, Jean-Marc Bonnet-Bidaud

We present mid-infrared spectrophotometric results obtained with the ISO on the peculiar X-ray binary Cygnus X-3 in quiescence, at orbital phases 0.83 to 1.04. The 2.4-12 microns continuum radiation observed with ISOPHOT-S can be explained by thermal free-free emission in an expanding wind with, above 6.5 microns, a possible additional black-body component w

Paul D. Dobbie, David J. Pinfield, Richard F. Jameson, Simon T. Hodgkin

We present evidence which indicates the luminosity functions of star forming regions, open star clusters and the field dips between spectral types M7-M8. We attribute this to a sharp local drop in the luminosity-mass relation and speculate that this is caused by the beginning of dust formation in the atmospheres of objects in this effective temperature regim

Frode K. Hansen, Krzysztof M. Gorski, Eric Hivon

The Fourier transform of a dataset apodised with a window function is known as the Gabor transform. In this paper we extend the Gabor transform formalism to the sphere with the intention of applying it to CMB data analysis. The Gabor coefficients on the sphere known as the pseudo power spectrum is studied for windows of different size. By assuming that the p

A. Natta, L. Testi, F. Comeron, E. Oliva

This paper discusses evidence for and properties of disks associated to brown dwarfs in the star-forming region rho-Oph. We selected nine objects fr om the ISOCAM survey of Bontemps et al. (2001) that have detections in the two mid-infrared bands (6.7 and 14.3 um), relatively low extinction and low luminosity. We present low-resolution near-infrared spectra

Inga Kamp, Ernst Paunzen

The lambda Bootis stars, a group of late B to early F-type population I stars, have surface abundances that resemble the general metal depletion pattern found in the interstellar medium. Inspired by the recent result that the fundamental parameters of these peculiar stars differ in no respect from a comparison sample of normal stars, the hypothesis of an int

L. F. Whyte, R. G. Abraham, M. R. Merrifield, P. B. Eskridge

To quantify the distribution of bar shapes in spiral galaxies, we have analysed 113 H-band and 89 B-band galaxy images from the Ohio State University Bright Spiral Galaxy Survey. Parameters measuring bar shape and position along the Hubble sequence were obtained in each waveband. Evidence was found for a bimodality in the distribution of bar shape, implying

L. Fuhrmann, G. Cimò, T. P. Krichbaum, T. Beckert

The evidence for refractive interstellar scintillation (RISS) being the main cause for rapid intraday variations (Intraday Variability, IDV) in Quasars and BL Lacs has recently become stronger. If IDV is still a complex composition of extrinsic and source intrinsic effects, the intrinsic part of the IDV pattern should show up in the millimeter and sub-millim

Uriel Giveon, Christophe Morisset, Amiel Sternberg

Two independent groups (Giveon et al. 2002; Martin-Hernandez et al. 2002) have recently investigated the Galactic metallicity gradient as probed by ISO observations of mid-infrared emission lines from HII regions. We show that the different gradients inferred by the two groups are due to differing source selection and differing extinction corrections. We sho

D. Rigopoulou, A. Franceschini, H. Aussel, R. Genzel

We report the first results from a study of the internal kinematics, based on spatially resolved H_alpha velocity profiles, of three galaxies at redshift z~0.6 and one at redshift z~0.8, detected by ISOCAM in the Hubble Deep Field South. The kinematics are derived from high resolution near-infrared VLT spectroscopy. One of the galaxies is a massive spiral wh

Frederic Daigne, Robert Mochkovitch

The prompt emission of gamma-ray bursts probably comes from a highly relativistic wind which converts part of its kinetic energy into radiation via the formation of shocks within the wind itself. Such "internal shocks" can occur if the wind is generated with a highly non uniform distribution of the Lorentz factor. We estimate the expected photospheri

J. Snigula, N. Drory, R. Bender, C. S. Botzler

We present the results of completeness simulations for the detection of point sources as well as redshifted elliptical and spiral galaxies in the K'-band images of the Munich Near-Infrared Cluster Survey (MUNICS). The main focus of this work is to quantify the selection effects introduced by threshold-based object detection algorithms used in deep imagin

Chaitra A. Narayan, Chanda J. Jog

For the past twenty years, it has been accepted that the vertical scaleheight of the stellar disk in spiral galaxies is constant with radius. However, there is no clear physical explanation for this in the literature. Here we calculate the vertical stellar scaleheight for a self-gravitating stellar disk including the additional gravitational force of the HI

G. A. J. Hussain, A. A. van Ballegooijen, M. Jardine, A. Col lier Cameron

We re-analyse spectropolarimetric data of AB Dor taken in 1996 December using a surface imaging code that can model the magnetic field of the star as a non-potential current-carrying magnetic field. We find that a non-potential field needs to be introduced in order to fit the dataset at this epoch. This non-potential component takes the form of a strong unid

S. T. Gottesman, J. H. Hunter, V. Boonyasait

Recent work by several groups has established the properties of the dwarf satellites to M31. We reexamine the reported kinematics of this group employing a fresh technique we have developed previously. By calculating the distribution of a chi statistic (which we define in the paper) for the M31 system, we conclude that the total mass (disk plus halo) of the

Martin Loidl

Several aspects of the motivation for particle dark matter search are introduced. The experimental principles and present state of the most important experiments are presented. Direct searches for WIMPs are explained in some detail, indirect WIPM searches and axion searches are presented more briefly.

N. D. R. Bhat, J. M. Cordes, S. Chatterjee

Multipath propagation in the interstellar medium distorts radio pulses, an effect predominant for distant pulsars observed at low frequencies. Typically, broadened pulses are analyzed to determine the amount of propagation-induced pulse broadening, but with little interest in determining the undistorted pulse shapes. In this paper we develop and apply a meth

Guillermo Cortiñas, Christian Valqui

We extend Cuntz-Quillen's excision theorem for algebras and pro-algebras in arbitrary Q-linear categories with tensor product.The excision theorems for the bivariant periodic cyclic cohomology of discrete,topological and bornological algebras and pro-algebras follow from this.

Abhay Ashtekar, Badri Krishnan

Dynamical horizons are considered in full, non-linear general relativity. Expressions of fluxes of energy and angular momentum carried by gravitational waves across these horizons are obtained. Fluxes are local, the energy flux is positive and change in the horizon area is related to these fluxes. The flux formulae also give rise to balance laws analogous to

M. R. Setare, M. B. Altaie

In this paper, we consider the Casimir energy of massless scalar field which satisfy Dirichlet boundary condition on a spherical shell. Outside the shell, the spacetime is assumed to be described by the Schwarzschild metric, while inside the shell it is taken to be the flat Minkowski space. Using zeta function regularization and heat kernel coefficients we i

J. Daniel Christensen, Mark Tilford

Subset take-away is a two-player game involving a fixed finite set A. Players alternate choosing a proper, non-empty subset of A, with the condition that one may not name a set containing a set that was named earlier. A player unable to move loses. It was conjectured by David Gale that this game is always a second player win, and this was known to hold if A

A. Frank, E. Blackman

Winds from accretion disks have been proposed as the driving source for precessing jets and extreme bipolar morphologies in Planetary Nebulae (PNe) and proto-PNe (pPNe). In this paper we address the applicability MHD disk wind models to PNe and pPNe. We first review Pelletier & Pudritz's (1992) non self-similar approach to magneto-centrifugal disk winds.

H. Ahmedov, I. H. Duru

Casimir interactions (due to the massless scalar field fluctuations) of two surfaces which are close to each other are studied. After a brief general presentation, explicit calculations for co-axial cylinders, co-centric spheres and co-axial cones are performed.

A. Sudbø, E. Smørgrav, J. Smiseth, F. S. Nogueira

We use a novel method of computing the third moment M_3 of the action of the 2+1-dimensional compact Higgs model in the adjoint representation with q=2 to extract correlation length and specific heat exponents nu and alpha, without invoking hyperscaling. Finite-size scaling analysis of M_3 yields the ratio (1+alpha)/nu and 1/nu separately. We find that alpha

Grigori L. Litvinov

The error autocorrection effect means that in a calculation all the intermediate errors compensate each other, so the final result is much more accurate than the intermediate results. In this case standard interval estimates are too pessimistic. We shall discuss a very strong form of the effect which appears in rational approximations to functions, where ver

Stephen D. H. Hsu

We investigate the intrinsic parity of black holes. It appears that discrete symmetries require the black hole Hilbert space to be larger than suggested by the usual quantum numbers M (mass), Q (charge) and J (angular momentum). Recent results on black hole production in trans-Planckian scattering lead to gravitational effects which do not decouple from low-

Karl Hess, Walter Philipp

Mermin states in a recent paper that his nontechnical version of Bell's theorem stands and is not invalidated by time and setting dependent instrument parameters as claimed in one of our previous papers. We identify a number of misinterpretations (of our definitions) and mathematical inconsistencies in Mermin's paper and show that Mermin's conclu

Kai Bongs, Romain Launay, Mark A. Kasevich

High-order inertial phase shifts are calculated for time-domain atom interferometers. We obtain closed-form analytic expressions for these shifts in accelerometer, gyroscope, optical clock and photon recoil measurement configurations. Our analysis includes Coriolis, centrifugal, gravitational, and gravity gradient-induced forces. We identify new shifts which

Masaru Kamata, Atsushi Nakamula

An attempt is given to formulate the extensions of the KP hierarchy by introducing fractional order pseudo-differential operators. In the case of the extension with the half-order pseudo-differential operators, a system analogous to the supersymmetric extensions of the KP hierarchy is obtained. Unlike the supersymmetric extensions, no Grassmannian variable a

Suhas N. Diggavi, N. J. A. Sloane, Vinay A. Vaishampayan

We consider the design of asymmetric multiple description lattice quantizers that cover the entire spectrum of the distortion profile, ranging from symmetric or balanced to successively refinable. We present a solution to a labeling problem, which is an important part of the construction, along with a general design procedure. This procedure is illustrated u

J. H. Conway, N. J. A. Sloane

A construction for sphere packings is introduced that is parallel to the ``anticode'' construction for codes. This provides a simple way to view Vardy's recent 20-dimensional sphere packing, and also produces packings in dimensions 22, 44--47 that are denser than any previously known.

J. H. Conway, R. K. Guy, W. A. Schneeberger, N. J. A. Sloane

We call a composite number q such that there exists a positive integer b with b^p == b (mod q) a prime pretender to base b. The least prime pretender to base b is the primary pretender q_b. It is shown that there are only 132 distinct primary pretenders, and that q_b is a periodic function of b whose period is the 122-digit number 195685843334600725872453400

Alex Chigogidze, Vesko Valov

Some generalizations of the classical Hurewicz formula are obtained for extension dimension and C-spaces.

R. P. Woodard

I reply to the objections recently raised by J. Llosa to my constructive proof that Lagrangians with nonlocality of finite extent inherit the full Ostrogradskian instability.

Kh. M. Beshtoev

This work is devoted to the discussion of an idea that gravitational interactions might be residual interactions of strong and electromagnetic interactions. Then, absence of the carriers of the gravitational interactions finds a natural explanation in the framework this idea. Besides, since masses (charges of the gravitational interactions) of particles are

V. E. Shemi-Zadeh

A new approach to the phenomenon of large numbers coincidence leads to unexpected results. No matter how strange it might sound, the exact value of cosmological parameters and their analytical expression through fundamental constants have been founded. The basis for obtaining these unusual results is the equality of the fundamental Large Number to the expone

Dina Goldin, Peter Wegner

The goal of computational logic is to allow us to model computation as well as to reason about it. We argue that a computational logic must be able to model interactive computation. We show that first-order logic cannot model interactive computation due to the incompleteness of interaction. We show that interactive computation is necessarily paraconsistent,

Srinidhi Varadarajan, Naren Ramakrishnan

This paper studies the evaluation of routing algorithms from the perspective of reachability routing, where the goal is to determine all paths between a sender and a receiver. Reachability routing is becoming relevant with the changing dynamics of the Internet and the emergence of low-bandwidth wireless/ad-hoc networks. We make the case for reinforcement lea

Yadin Y. Goldschmidt, Yohannes Shiferaw

In this paper we investigate the problem of a long self-avoiding polymer chain immersed in a random medium. We find that in the limit of a very long chain and when the self-avoiding interaction is weak, the conformation of the chain consists of many ``blobs'' with connecting segments. The blobs are sections of the molecule curled up in regions of low

Roberto Monaco, Jesper Mygind, Ray J. Rivers

It has been argued by Zurek and Kibble that the likelihood of producing defects in a continuous phase transition depends in a characteristic way on the quench rate. In this paper we discuss our experiment for measuring the Zurek-Kibble scaling exponent sigma for the production of fluxons in annular symmetric Josephson Tunnel Junctions. The predicted exponent

K. C. Lakshmi, P. B. Sunil Kumar

Phase separation in binary and ternary fluids is studied using a two dimensional Lattice Gas Automata. The lengths, given by the the first zero crossing point of the correlation function and the total interface length is shown to exhibit power law dependence on time. In binary mixtures, our data clearly indicate the existence of a regime having more than one

A. V. Silhanek, L. Civale, J. R. Thompson, P. C. Canfield

We present an overview of the temperature, field and angular dependence of the irreversible magnetization of non-magnetic borocarbides (Y;Lu) Ni_2 B_2 C. We show that nonlocal electrodynamics influences pinning via the unusual behavior of the shear modulus in non-hexagonal lattices. On top of that, we observe that the pinning force density F_p exhibits a ric

M. A. Skvortsov, D. A. Ivanov, G. Blatter

We present a microscopic calculation of the energy dissipation in the core of a vortex moving in a two-dimensional or layered superconductor in the moderately clean regime. In this regime, the quasiclassical Bardeen--Stephen result remains valid in spite of the strong correlations between the energy levels. We find that the quasiclassical expression applies

Michael Efroimsky

We develop a comprehensive quantitative description of the cross-section mechanism discovered several years ago by Lazarian. This is one of the processes that determine grain orientation in clouds of suprathermal cosmic dust. The cross-section mechanism manifests itself when an ensemble of suprathermal paramagnetic granules is placed in a magnetic field and

S. Marri, S. D. M. White

We investigate a new implementation of the Smoothed Particle Hydrodynamics technique (SPH) designed to improve the realism with which galaxy formation can be simulated. In situations where cooling leads to the coexistence of phases of very different density and temperature, our method substantially reduces artificial overcooling near phase boundaries, preven

Dan Maoz, Alex Markowitz, Rick Edelson, Kirpal Nandra

We present optical broadband (B and R) observations of the Seyfert 1 nucleus NGC 3516, obtained at Wise Observatory from March 1997 to March 2002, contemporaneously with X-ray 2-10 keV measurements with RXTE. With these data we increase the temporal baseline of this dataset to 5 years, more than triple to the coverage we have previously presented for this ob

A. Vikhlinin, L. VanSpeybroeck, M. Markevitch, W. R. Forman

We derive correlations between X-ray temperature, luminosity, and gas mass for a sample of 22 distant, z>0.4, galaxy clusters observed with Chandra. We detect evolution in all three correlations between z>0.4 and the present epoch. In particular, in the Omega=0.3, Lambda=0.7 cosmology, the luminosity corresponding to a fixed temperature scales approximately

Siddhartha Bhowmick, Jishnu Dey, Mira Dey, Subharthi Ray

A modified version of this paper is under process and with a new title and abstract. Hence, this version of the article is completely withdrawn.

M. Przanowski, F. J. Turrubiates

Robertson and Hadamard-Robertson theorems on non-negative definite hermitian forms are generalized to an arbitrary ordered field. These results are then applied to the case of formal power series fields, and the Heisenberg-Robertson, Robertson-Schrödinger and trace uncertainty relations in deformation quantization are found. Some conditions under which the u

Ben O'Shaughnessy, Dimitrios Vavylonis

Synthetic and biological living polymers are self-assembling chains whose chain length distributions (CLDs) are dynamic. We show these dynamics are ultrasensitive: even a small perturbation (e.g. temperature jump) non-linearly distorts the CLD, eliminating or massively augmenting short chains. The origin is fast relaxation of mass variables (mean chain lengt

Jun-Ichi Yamaura, Zenji Hiroi

We report the X-ray study for the pyrochlore oxide Cd2Re2O7. Two symmetry-lowering structural transitions were observed at Ts1=200K and Ts2=120K. The former is of the second order from the ideal cubic pyrochlore structure with space group Fd-3m to a tetragonally distorted structure with I-4m2, while the latter is of the first order likely to another tetragon

Y. Satou, S. Ishida, H. Sakai, H. Okamura

We have measured the cross sections and analyzing powers Ay and Ayy for the elastic and inelastic scattering of deuterons from the 0+(g.s.), 2+(4.44 MeV), 3-(9.64 MeV), 1+(12.71 MeV), and 2-(18.3 MeV) states in 12C at an incident energy of 270 MeV. The data are compared with microscopic distorted-wave impulse approximation calculations where the projectile-n

Andrei A. Kapaev

For the bi-orthogonal polynomials with the third degree polynomial potential functions, the 3 x 3 matrix Riemann-Hilbert problem is explicitly constructed. The developed approach admits an extension to the bi-orthogonal polynomials with arbitrary polynomial potentials.

X. Y. Wang, Z. G. Dai, T. Lu

The absorption feature detected in the prompt X-ray emission of GRB990705 has important consequences for its circum-burst environment and therefore on its afterglows. Here we investigate whether the circum-burst environment constrained by the absorption feature could be consistent with the observed H-band afterglow, which exhibits an earlier power law decay

M. S. Shahriar, Prabhakar Pradhan, Jacob Morzinski

We show that the phase of a field can be determined by incoherent detection of the population of one state of a two-level system if the Rabi frequency is comparable to the Bohr frequency so that the rotating wave approximation is inappropriate. This implies that a process employing the measurement of population is not a square-law detector in this limit. We

G. W. Greenwood

It has previously been proven that finding the globally minimum energy configuration of an atomic cluster belongs in the class of NP-hard problems. However, this proof is limited only to homonuclear clusters. This paper presents a new proof which shows finding minimum energy configurations for heteronuclear clusters is also NP-hard.

Asish Ganguly

Using representations of sl(2,R) generators which yield associated Lame Hamiltonians we obtain new classes of elliptic potentials. We explicitly calculate eigenvalues and spectra for these potentials and construct the associated orthogonal polynomials. We show that in the proper limit these potentials reduce to well-known exactly solvable potentials.

A. Yu. Savin, B. -W. Schulze, B. Yu. Sternin

The spectral eta-invariant of a self-adjoint elliptic differential operator on a closed manifold is rigid, provided that the parity of the order is opposite to the parity of dimension of the manifold. The paper deals with the calculation of the fractional part of the eta-invariant in this case. The method used to obtain the corresponding formula is based on

A. Yu. Savin, B. Yu. Sternin

We define a class of boundary value problems on manifolds with fibered boundary. This class is in a certain sense a deformation between the classical boundary value problems and the Atiyah-Patodi-Singer problems in subspaces. The boundary conditions in this theory are taken as elements of the C^*-algebra generated by pseudodifferential operators and families

J. H. Conway, E. M. Rains, N. J. A. Sloane

Partial answers are given to two questions. When does a lattice Lambda contain a sublattice Lambda' of index N that is geometrically similar to Lambda? When is the sublattice "clean", in the sense that the boundary of the Voronoi cells for Lambda ' do not intersect Lambda?

E. M. Rains, N. J. A. Sloane

Cayley's 1875 enumerations of centered and bicentered alkanes (unlabeled trees of valency at most 4) are corrected and extended -- possibly for the first time in 124 years.

N. J. A. Sloane

This paper gives a brief description of the author's database of integer sequences, now over 35 years old, together with a selection of a few of the most interesting sequences in the table. Many unsolved problems are mentioned.

Donatella Donatelli, Pierangelo Marcati

In this paper we investigate the zero-relaxation limit of the following multi-D semilinear hyperbolic system in pseudodifferential form: W_{t}(x,t) + (1/epsilon) A(x,D) W(x,t) = (1/epsilon^2) B(x,W(x,t)) + (1/epsilon) D(W(x,t)) + E(W(x,t)). We analyse the singular convergence, as epsilon tends to 0, in the case which leads to a limit system of parabolic type

Stefan Schroeer

I show that each etale n-cohomology class on noetherian schemes comes from a Cech cocycle, provided that any n-tuple of points admits an affine open neighborhood. Together with results of Raeburn and Taylor on the bigger Brauer group, this implies that for schemes such that each pair of points admits an affine open neighborhood, any etale G_m-gerbe comes fro

Paul Seidel

The long exact sequence describes how the Floer cohomology of two Lagrangian submanifolds changes if one of them is modified by applying a Dehn twist. We give a proof in the simplest case (no bubbling). The paper contains a certain amount of material that may be of interest independently of the exact sequence: in particular, chapter 1 covers "symplectic

A. Yu. Savin, B. Yu. Sternin

The topological significance of the spectral Atiyah-Patodi-Singer eta-invariant is investigated under the parity conditions of P. Gilkey. We show that twice the fractional part of the invariant is computed by the linking pairing in K-theory with the orientation bundle of the manifold. The Pontrjagin duality implies the nondegeneracy of the linking form. An e

Marco Bruni, Peter K. S. Dunsby

Recent studies of homogeneous anisotropic universe models in the brane world scenario show that the cosmological singularity in this context is isotropic. It has therefore been suggested that this may be a generic feature of singularities on the brane, even in the inhomogeneous case. Using a perturbative approach, we show that this is not the case. As in the

F. Anselmo, J. Ellis, D. V. Nanopoulos, G. Volkov

We present a universal normal algebra suitable for constructing and classifying Calabi-Yau spaces in arbitrary dimensions. This algebraic approach includes natural extensions of reflexive weight vectors to higher dimensions, related to Batyrev's reflexive polyhedra, and their n-ary combinations. It also includes a `dual' construction based on the Dio

Marek Rogatko

We prove the uniqueness theorem for self-gravitating non-linear sigma-models in higher dimensional spacetime. Applying the positive mass theorem we show that Schwarzschild-Tagherlini spacetime is the only maximally extended, static asymptotically flat solution with non-rotating regular event horizon with a constant mapping.

A. Dymarsky

We derive the couplings of D-branes to the RR fields from the first principles, i.e. from the nonlinear sigma-model. We suggest a procedure to extract poles from string amplitudes, before the eventual formula for the couplings is obtained. Using the fact that the parts of amplitudes with poles are irrelevant for the effective action this procedure ultimately

Guenter Sigl

The observed interaction energy of cosmic rays with atmospheric nuclei reaches up to a PeV in the center of mass. We compute nucleon-nucleon and nucleon-neutrino cross sections for various generic parton cross sections appearing in string and brane world scenarios for gravity and compare them with cosmic ray data. Scenarios with effective energy scales in th

Iain W. Stewart

In this talk I review an effective field theory that has been developed for processes with energetic hadrons, referred to as the Soft-Collinear Effective Theory. After outlining properties of the effective theory I briefly discuss its application to the processes B -> D pi and B -> Xs gamma.

Jacques Soffer, Oleg V. Teryaev

A description of the generalized Gerasimov-Drell-Hearn sum rules for proton and neutron is suggested, using their relation to the Bjorken sum rule. The results support an earlier conjecture, that the structure function g_T features a smooth Q^2-dependence, while the structure function g_2 is changing rapidly, due to the elastic contribution to the Burkhardt-

K. C. Shin

We consider the eigenvalue problems -u"(z) +/- (iz)^m u(z) = lambda u(z), m >= 3, under every rapid decay boundary condition that is symmetric with respect to the imaginary axis in the complex z-plane. We prove that the eigenvalues lambda are all positive real.

J. Blümlein, D. Robaschik

Polarized inclusive deep-inelastic scattering is formulated in the light cone expansion. The QCD evolution of the leading twist distribution functions is derived. It is shown that the twist--2 contribution to the structure functions g_2^{D(3)} is obtained via g_1^{D(3)} by a Wandzura--Wilczek relation.

Marco Cadoli, Thomas Eiter, Georg Gottlob

The need for a circumscriptive formalism that allows for simple yet elegant modular problem representation has led Lifschitz (AIJ, 1995) to introduce nested abnormality theories (NATs) as a tool for modular knowledge representation, tailored for applying circumscription to minimize exceptional circumstances. Abstracting from this particular objective, we pro

S. Cocco, R. Monasson, J. F. Marko

The two strands of the DNA double helix can be `unzipped' by application of 15 pN force. We analyze the dynamics of unzipping and rezipping, for the case where the molecule ends are separated and re-approached at constant velocity. For unzipping of 50 kilobase DNAs at less than about 1000 bases per second, thermal equilibrium-based theory applies. Howeve