October 1999 arXiv papers — page 3

I. R. Pimentel, F. Carvalho Dias, L. M. Martelo, R. Orbach

We study the spin excitations and the transverse susceptibility of a two-dimensional antiferromagnet doped with a small concentration of holes in the t-J model. The motion of holes generates a renormalization of the magnetic properties. The Green's functions are calculated in the self-consistent Born approximation. It is shown that the long-wavelength sp

V. Bruyndoncx, L. Van Look, V. V. Moshchalkov

The normal/superconducting phase boundary Tc has been calculated for mesoscopic loops, as a function of an applied perpendicular magnetic field H. While for thin-wire loops and filled disks the Tc(H) curves are well known, the intermediate case, namely mesoscopic loops of finite wire width, have been studied much less. The linearized first Ginzburg-Landau eq

Abhishek Dhar, Pinaki Chaudhuri, Chandan Dasgupta

We study the equilibrium properties of the nearest-neighbor Ising antiferromagnet on a triangular lattice in the presence of a staggered field conjugate to one of the degenerate ground states. Using a mapping of the ground states of the model without the staggered field to dimer coverings on the dual lattice, we classify the ground states into sectors specif

Debra J Searles, Gary Ayton, Denis J Evans

We develop a General Fluctuation Formula for phase variables that are odd under time reversal. Simulations are used to verify the new formula.

R. G. Mints, E. H. Brandt

We predict a novel buckling instability in the critical state of thin type-II superconductors with strong pinning. This elastic instability appears in high perpendicular magnetic fields and may cause an almost periodic series of flux jumps visible in the magnetization curve. As an illustration we apply the obtained criteria to a long rectangular strip.

Paolo Politi, Joachim Krug

We study the effect of crystal symmetry and step-edge diffusion on the surface current governing the evolution of a growing crystal surface. We find there are two possible contributions to anisotropic currents, which both lead to the destabilization of the flat surface: terrace current (j_t), which is parallel to the surface slope, and step current (j_s), wh

S. Goedecker, E. Koch

For non-interacting electrons the one-particle density matrix and the related Wannier functions characterize a material as insulating or metallic. Introducing many-body Wannier functions, we show that this characterization can be carried over to interacting systems. In particular, we find that an exponential decay of the density matrix characterizes not only

M. Khodas, S. Fishman

The dynamics of the kicked-rotor, that is a paradigm for a mixed system, where the motion in some parts of phase space is chaotic and in other parts is regular is studied statistically. The evolution (Frobenius-Perron) operator of phase space densities in the chaotic component is calculated in presence of noise, and the limit of vanishing noise is taken is t

Wen Xu, Li-Zhi Fang, Xiang-Ping Wu

Using samples of structures identified by a multi-scale decomposition from numerical simulation, we analyze the scale-dependence of the virialization of clusters. We find that beyond the scale of full virialization there exists a radius range over which clusters are quasi-virialized, i.e. while the internal structure of an {\it individual} cluster is at subs

Silviu Podariu, Bharat Ratra

The energy density of a scalar field $ϕ$ with potential $V(ϕ) \propto ϕ^{-α}$, $α> 0$, behaves like a time-variable cosmological constant that could contribute significantly to the present energy density. Predictions of this spatially-flat model are compared to recent Type Ia supernovae apparent magnitude versus redshift data. A large region of model paramet

E. A. Richards

I describe an observational program aimed at understanding the radio emission from distant, rapidly evolving galaxy populations. These observations were carried out at 1.4 and 8.5 GHz with the VLA centered on the Hubble Deep Field. Further MERLIN observations of the HDF region at 1.4 GHz provided an angular resolution of 0.2" and when combined with the VLA d

E. V. Gotthelf, G. Vasisht, K. Torii, B. M. Gaensler

We present a follow-up X-ray and radio study of the field containing the 7-s X-ray pulsar AX J1845-0258, the serendipitous ASCA source whose characteristics are found to be similar to those of the anomalous X-ray pulsars (AXPs). Newly acquired ASCA data confirms a dramatic reduction in flux from the pulsar and reveals instead a faint X-ray point source, AX J

A. E. Dolphin

Ground-based UBV photometry of two fields in the northern disk of the LMC are presented. A distance modulus of (m-M)_0 = 18.41 +/- 0.04 and an extinction of A_V = 0.30 +/- 0.05 has been calculated for these fields. The measurable star formation history of the LMC began no more than 12 Gyr ago with a strong star forming episode with [Fe/H] = -1.63 +/- 0.10 th

L. M. Lubin, C. D. Fassnacht, A. C. S. Readhead, R. D. Blandford

We present new results from a continuing Keck program to study gravitational lens systems. We have obtained redshifts for three lens systems, SBS 0909+532, HST 1411+5211, and CLASS B2319+051. For all of these systems, either the source or lens redshift (or both) has been previously unidentified. We find (z_l, z_s) = (0.830, 1.377) for SBS 0909+532; (z_l, z_s

M. Bellazzini, M. Messineo

We report on new WFPC2 observations of the globular cluster NGC 288, focusing our attention on peculiar stars. A very pronounced binary sequence, paralleling the ordinary Main Sequence (MS) is clearly observed in the Color Magnitude Diagram (CMD) and a huge relative fraction of Blue Straggler Stars is measured. The dataset offers the opportunity of studying

F. Cuisinier, W. J. Maciel, J. Köppen, A. Acker

High quality spectrophotometric observations of 30 Planetary Nebulae in the Galactic Bulge have been made. Accurate reddenings, plasma parameters, and abundances of He,O,N,S,Ar,Cl are derived. We find the abundances of O,S,Ar in the Planetary Nebulae in the Galactic Bulge to be comparable with the abundances of the Planetary Nebulae in the Disk, high abundan

A. Cassatella, A. Altamore, R. Gonzalez-Riestra, J. D. Ponz

In this paper we document the results of the study which led to the ripple correction and absolute calibration algorithms applied to the high resolution spectra processed with the NEWSIPS software for the Final Archive of the IUE Project. In this analysis, based on a very large number of spectra, we find that both K and the alpha parameters (not only the for

Gregory J. Sobczak, Jeffrey E. McClintock, Ronald A. Remillard, Wei Cui

Utilizing observations obtained with the Rossi X-ray Timing Explorer, we examine correlations between the properties of 0.08-22 Hz variable frequency QPOs and the X-ray spectral parameters for the black hole candidates XTE J1550-564 and GRO J1655-40. The spectra were fitted to a model including a multi-temperature blackbody disk and a power-law component. We

R. Gonzalez-Riestra, A. Cassatella, E. Solano, A. Altamore

This paper discusses the overall quality of IUE high resolution data processed with the NEWSIPS software in terms of flux and wavelength accuracy. It also describes the processing of NEWSIPS high resolution spectra within the framework of the ESA ``IUE Newly Extracted Spectra'' (INES) System. This system provides the IUE high resolution data in two f

J. Krautter, F. -J. Zickgraf, I. Appenzeller, I. Thiering

We present the statistical evaluation of a count rate and area limited complete sample of the ROSAT All-Sky Survey (RASS) comprising 674 sources. The RASS sources are located in six study areas outside the galactic plane (|b^II| >= 20 deg) and north of delta = -9 deg. The total sample contains 274 (40.7%) stars, 26 (3.9%) galaxies, 284 (42.1%) AGN, 78 (11.6%

Rita M. Sambruna, Michael Eracleous, Richard Mushotzky

We present an X-ray spectral survey of radio-loud (RL) AGNs using ASCA and RXTE. The goal was to study the structure of their central engines and compare it to that of their radio-quiet (RQ) counterparts. We find Systematic differences in the X-ray properties of the two AGN classes. Specifically, RL AGNs exhibit weaker Fe lines and reflection components than

S. K. Saha, R Rajamohon, P Vivekananda Rao, G Som Sunder

Speckle interferometric technique has been used to obtain a series of short exposure images of the collision of comet Shoemaker-Levy 9 with Jupiter during the period of July 17-24, 1994 using the Nasmyth focus of 1.2 meter telescope of Japal-Rangapur Observatory, Hyderabad. The technique of Blind Iterative Deconvolution (BID) was used to remove the atmospher

K. Pottschmidt, J. Wilms, R. Staubert, M. A. Nowak

We present first results from the spectral and temporal analysis of an RXTE monitoring campaign of the black hole candidate Cygnus X-1 in 1999. The timing properties of this hard state black hole show considerable variability, even though the state does not change. This has previously been noted for the power spectral density, but is probably even more prono

J. Wilms, M. A. Nowak, K. Pottschmidt, W. A. Heindl

The black hole candidate LMC X-3 varies by a factor of four in the soft X-rays on a timescale of 200 or 100days. We have monitored LMC X-3 with RXTE in three to four week intervals starting in December 1996, obtaining a large observational database that sheds light on the nature of the long term X-ray variability in this source. In this paper we present the

S K Saha, A P Jayarajan, G Sudheendra, A Umesh Chandra

An interferometer system for use at the 2.34 meter Vainu Bappu Telescope (VBT), situated at Vainu Bappu Observatory (VBO), Kavalur, to obtain speckle-grams of astronomical objects in the visible wavelength, has been developed. Laboratory tests of resultant intensity distributions due to a point source, with phase modulation screens, as well as the images obt

S. K. Saha

We have presented the basic mathematical treatment of interferometry in the optical domain. Its applications in astronomical observations using both the single aperture, as well as the diluted apertures are described in detail. We have also described about the shortcomings of this technique in the presence of Earth's atmosphere. A short descriptions of t

Masahiro Tsujimoto, Kensuke Imanishi, Jun Yokogawa, Katsuji Koyama

We report on the discovery and analysis of an X-ray pulsar, AX J0058-7203, in the Small Magellanic Cloud. This pulsar exhibits coherent pulsations at P= 280.3 s with a double-peak structure. The X-ray spectrum is well fitted with a simple power-law model of photon index ~ 0.7. No significant change of the pulsation period over the observation was found. A co

J. B. Peterson, G. S. Griffin, M. G. Newcomb, D. L. Alvarez

Results of a search for small-scale anisotropy in the cosmic microwave background (CMB) are presented. Observations were made at the South Pole using the Viper telescope, with a .26 degree (FWHM) beam and a passband centered at 40 GHz. Anisotropy band-power measurements in bands centered at l = 108, 173, 237, 263, 422 and 589 are reported. Statistically sign

E. A. Richards, F. E. Bauer, A. J. Barger, L. Cowie

Using a combination of radio and optical imaging at 0.1\arcs to 0.2\arcs resolution with the VLA/MERLIN and HST has led to a breakthrough in our understanding of radio emission from distant (0.1<z<3) starburst galaxies. We have recently isolated a number of high redshift, dusty starburst galaxies that remain invisible in ground based images to I_{AB}=25 and

Andrei Gruzinov

When a bright spot in a high-inclination disk orbits a black hole, its light is periodically lensed and Doppler shifted. If the spots occupy a narrow range of radii, a quasi-periodic oscillation (QPO) will result. I calculate the QPO frequency assuming that the spots appear near r_max - the radius of the maximal proper radiation flux from the disk. The calcu

H. Jirari, H. Kröger, X. Q. Luo, K. J. M. Moriarty

Based on a closed form expression for the path integral of quantum transition amplitudes, we suggest rigorous definitions of both, quantum instantons and quantum chaos. As an example we compute the quantum instanton of the double well potential.

Pierre Binetruy, Cedric Deffayet, Ulrich Ellwanger, David Langlois

We consider the cosmology of a ``3-brane universe&#39;&#39; in a five dimensional (bulk) space-time with a cosmological constant. We show that Einstein&#39;s equations admit a first integral, analogous to the first Friedmann equation, which governs the evolution of the metric in the brane, whatever the time evolution of the metric along the fifth dimension.

Ivica Res, Joseph P. Straley

Conformal transformations can be used to obtain the order parameter for two-dimensional systems at criticality in finite geometries with fixed boundary conditions on a connected boundary. To the known examples of this class (such as the disk and the infinite strip) we contribute the case of a rectangle. We show that the order parameter profile for simply con

Paul B. Slater

For certain infinite and finite-dimensional thermal systems, we obtain --- incorporating quantum-theoretic considerations into Bayesian thermostatistical investigations of Lavenda --- high-temperature expansions of priors over inverse temperature beta induced by volume elements (&#34;quantum Jeffreys&#39; priors) of Bures metrics. Similarly to Lavenda&#39;s

Paul H. Frampton, Andrija Rasin

Nonabelian discrete groups are an attractive tool to describe fermion masses and mixings. They have nonsinglet representations which seem particularly suitable for distinguishing the lighter generations from the heavier ones. Also, they do not suffer from the extra constraints a continuous group must obey, e.g. limits on extra particles. Some of the simplest

V. Barger, K. Cheung, T. Han, C. Kao

We explore the capabilities for new physics discovery in proton-antiproton collisions at 5.4 TeV center-of-mass energy with luminosity $10^{33} cm^{-2} s^{-1}$ at a Tripler upgrade of the Tevatron collider. The prospects are robust for the usual Higgs boson and supersymmetry benchmarks. With an integrated luminosity of 40 fb$^{-1}$, discoveries at 5$σ$ could

Matias Zaldarriaga

We study the generation of CMB anisotropies by gravitational lensing on small angular scales. We show these fluctuations are not Gaussian. We prove that the power spectrum of the tail of the CMB anisotropies on small angular scales directly gives the power spectrum of the deflection angle. We show that the generated power on small scales is correlated with t

Abhay Ashtekar

The arena normally used in black holes thermodynamics was recently generalized to incorporate a broad class of physically interesting situations. The key idea is to replace the notion of stationary event horizons by that of `isolated horizons.' Unlike event horizons, isolated horizons can be located in a space-time quasi-locally. Furthermore, they need not b

Roger Haydock

A method is presented for calculating binding energies and other properties of extended interacting systems using the projected density of transitions (PDoT) which is the probability distribution for transitions of different energies induced by a given localized operator, the operator on which the transitions are projected. It is shown that the transition co

Kwon Park, J. K. Jain

The single mode approximation has proved useful for the excitation spectrum at $\nu=1/3$. We apply it to general fractions and find that it predicts $n$ magneto-roton minima in the dispersion of the Girvin-MacDonald-Platzman collective mode for the fractional quantum Hall states at $\nu=n/(2n+1)$, and one magneto-roton minimum for both the composite Fermi se

R. P. van der Marel, J. Magorrian, R. G. Carlberg, H. K. C. Yee

In the context of the CNOC1 cluster survey, redshifts were obtained for galaxies in 16 clusters. The resulting sample is ideally suited for an analysis of the internal velocity and mass distribution of clusters. Previous analyses of this dataset used the Jeans equation to model the projected velocity dispersion profile. However, the results of such an analys

A. Donini, M. B. Gavela, P. Hernandez, S. Rigolin

The prospects of measuring the leptonic angles and CP-odd phases at a {\em neutrino factory} are discussed in the scenario of three active plus one sterile neutrino. We consider the $ν_μ\raw ν_e$ LSND signal. Its associated large mass difference leads to observable neutrino oscillations at short ($\sim 1$ km) baseline experiments. Sensitivities to the lepton

Y. F. Huang, L. J. Gou, Z. G. Dai, T. Lu

Whether gamma-ray bursts are highly beamed or not is a very difficult but important problem that we are confronted with. Some theorists suggest that beaming effect usually leads to a sharp break in the afterglow light curve during the ultra-relativistic phase, with the breaking point determined by $γ= 1 / θ_0$, where $γ$ is the Lorentz factor of the blastwav

Ronald Dickman, Miguel A. Munoz, Alessandro Vespignani, Stefano Zapperi

We present a pedagogical introduction to self-organized criticality (SOC), unraveling its connections with nonequilibrium phase transitions. There are several paths from a conventional critical point to SOC. They begin with an absorbing-state phase transition (directed percolation is a familiar example), and impose supervision or driving on the system; two c

P. Di Francesco, O. Golinelli, E. Guitter

We conjecture that meanders are governed by the gravitational version of a c=-4 two-dimensional conformal field theory, allowing for exact predictions for the meander configuration exponent α=\sqrt{29}(\sqrt{29}+\sqrt{5})/12, and the semi-meander exponent {\barα}=1+\sqrt{11}(\sqrt{29}+\sqrt{5})/24. This result follows from an interpretation of meanders as pa

S. I. Kruglov

The effective action for baryons in the external electromagnetic fields is obtained on the basis of the QCD string theory. The area law of the Wilson loop integral, the approximation of the Nambu-Goto straight-line strings, and the asymmetric quark-diquark structure of nucleons are used to simplify the problem. The spin-orbit and spin-spin interactions of qu

J. I. Farran

A new effective decoding algorithm is presented for arbitrary algebraic-geometric codes on the basis of solving a generalized key equation with the majority coset scheme of Duursma. It is an improvement of Ehrhard's algorithm, since the method corrects up to the half of the Goppa distance with complexity order O(n**2.81), and with no further assumption on th

Manfried Faber

We introduce a model designed to describe charged particles as stable topological solitons of a field with values on the internal space S^3. These solitons behave like particles with relativistic properties like Lorentz contraction and velocity dependence of mass. This mass is defined by the energy of the soliton. In this sense this model is a generalisation

E. Deotto, G. Furlan, E. Gozzi

In this paper we propose a new supersymmetric extension of conformal mechanics. The Grassmannian variables that we introduce are the basis of the forms and of the vector-fields built over the symplectic space of the original system. Our supersymmetric Hamiltonian itself turns out to have a clear geometrical meaning being the Lie-derivative of the Hamiltonian

J. Luis Miramontes, C. R. Fernández-Pousa

A new family of S-matrix theories with resonance poles is constructed and conjectured to correspond to the Homogeneous sine-Gordon theories associated with simply laced compact Lie groups, where some of the resonance poles can be traced to the presence of unstable particles in the spectrum. These theories are unitary in the usual S S^\dagger =1 sense, they a

A. J. Benson, C. M. Baugh, S. Cole, C. S. Frenk

We use a combination of N-body simulations of the hierarchical clustering of dark matter and semi-analytic modelling of the physics of galaxy formation to probe the relationship between the galaxy distribution and the mass distribution. The pairwise line-of-sight velocity dispersion of galaxies is sensitive to the number of galaxies present in halos of diffe

Chris Doran

A new form of the Kerr solution is presented. The solution involves a time coordinate which represents the local proper time for free-falling observers on a set of simple trajectories. Many physical phenomena are particularly clear when related to this time coordinate. The chosen coordinates also ensure that the solution is well behaved at the horizon. The s

F. Shoji, T. Suzuki, H. Kodama, A. Nakamura

We formulate a stochastic gauge fixing method to study the gauge dependence of the Abelian projection. We consider a gauge which interpolates between the maximal Abelian gauge and no gauge fixing. We have found that Abelian dominance for the heavy quark potential holds even in a gauge which is far from maximally Abelian one. The heavy quark potentials from m

J. Suzuki

Recently, Dorey and Tateo have investigated functional relations among Stokes multipliers for a Schr{ö}dinger equation (second order differential equation) with a polynomial potential term in view of solvable models. Here we extend their studies to a restricted case of n+1-th order linear differential equations.

E. Bogomolny, N. Pavloff, C. Schmit

We derive contributions to the trace formula for the spectral density accounting for the role of diffractive orbits in two-dimensional polygonal billiards. In polygons, diffraction typically occurs at the boundary of a family of trajectories. In this case the first diffractive correction to the contribution of the family to the periodic orbit expansion is of

M. N. Achasov, V. M. Aulchenko, K. I. Beloborodov, A. V. Berdyugin

The current status of experiments with SND detector at VEPP-2M e^+e^- collider in the energy range 2E_0=400-1400 MeV and recent results of data analysis for $\phi$, $\omega$ and $\rho$ decays and e^+e^- annihilation into hadrons are presented.

A. Honecker, F. Mila, M. Troyer

We study the occurrence of plateaux and jumps in the magnetization curves of a class of frustrated ladders for which the Hamiltonian can be written in terms of the total spin of a rung. We argue on the basis of exact diagonalization of finite clusters that the ground state energy as a function of magnetization can be obtained as the minimum - with Maxwell co

Leonard Gamberg, Herbert Weigel

We present a consistent regularization procedure for calculating hadron structure functions in a bosonized chiral quark model. We find that the Pauli-Villars regularization scheme is most suitable. We also summarize the phenomenology of structure functions calculated in the valence quark approximation.

C. J. Houghton

In the generalized Legendre transform construction the Kaehler potential is related to a particular function. Here, the form of this function appropriate to the monopole metric is calculated from the known twistor theory of monopoles.

Zu-Guo Yu, Guo-Yi Chen

In this paper we treat some fractal and statistical features of the DNA sequences. First, a fractal record model of DNA sequence is proposed by mapping DNA sequences to integer sequences, followed by R/S analysis of the model and computation of the Hurst exponents. Second, we consider transition between the four kinds of bases within DNA. The transition matr

Vladimir Pestov

This is an account of one man&#39;s view of the current perspective of theory of topological groups. We survey some recent developments which are, from our viewpoint, indicative of the future directions, concentrating on actions of topological groups on compacta, embeddings of topological groups, free topological groups, and `massive&#39; groups (such as gro

Cetin Savkli

A knowledge of nonpertubative propagators is often needed when the standard perturbative methods are not applicable. An example of this is the bound state problem in field theory. While a nonperturbative result is valuable by itself, it is also an important guide for those who work on developing phenomenological models for the nonperturbative problem. The Fe

T. M. Aliev, C. S. Kim, Y. G. Kim

A model-independent analysis for the exclusive, rare B -> K^* l^+ l^- decay is presented. Systematically studied are the experimentally measured quantities, such as, branching ratio, forward-backward asymmetry, longitudinal polarization of the final leptons, and the ratio $Γ_L/Γ_T$ of the decay widths when $K^\ast$ meson is longitudinally and transversally p

Nistor Nicolaevici

We consider the quantum radiation from a partially reflecting moving mirror for the massless scalar field in 1+1 Minkowski space. Partial reflectivity is achieved by localizing a delta-type potential at the mirror&#39;s position. The radiated flux is exactly obtained for arbitrary motions as an integral functional of the mirror&#39;s past trajectory. Partial

Miloslav Znojil

I propose a new version of the Rayleigh - Schrödinger perturbation method. It admits a lower triangular matrix in place of the usual diagonal propagator. Illustrated on rational anharmonicities polynomial}(x)/polynomial}(x), treated as perturbations of (quasi-)exact anharmonic oscilators. In this sense the method works in an intermediate-coupling regime and

M. Fleischhauer

The phase transition to mirrorless oscillation in resonantly enhanced four-wave mixing in double-$Λ$ systems are studied analytically for the ideal case of infinite lifetimes of ground-state coherences. The stationary susceptibilities are obtained in all orders of the generated fields and analytic solutions of the coupled nonlinear differential equations for

H. Sasakura, S. Muto

Quantum computation using electron spins in three coupled dot with different size is proposed. By using the energy selectivity of both photon assisted tunneling and spin rotation of electrons, logic gates are realized by static and rotational magnetic field and resonant optical pulses. Possibility of increasing the number of quantum bits using the energy sel

O. H. Pakarinen, K. -A. Suominen

We investigate how the nonlinearity of the Zeeman shift for strong magnetic fields affects the dynamics of rf field induced evaporative cooling in magnetic traps. We demonstrate for the 87-Rb and 23-Na F=2 trapping states with wave packet simulations how the cooling stops when the rf field frequency goes below a certain limit (for the 85-Rb F=2 trapping stat

H. J. Haubold

During the second half of the twentieth century, expensive observatories are being erected at La Silla (Chile), Mauna Kea (Hawai), Las Palmas (Canary Island), and Calar Alto (Spain), to name a view. In 1990, at the beginning of The Decade of Discovery in Astronomy and Astrophysics (Bahcall [2]), the UN/ESA Workshops on Basic Space Science initiated the estab

H. J. Haubold

Education is a prerequisite to master the challenges of space science and technology. Efforts to understand and control space science and technology are necessarily intertwined with social expressions in the cultures where science and technology is carried out. The United Nations is leading an effort to establish regional Centres for Space Science and Techno

Zu-Guo Yu, Bai-lin Hao, Hui-min Xie, Guo-Yi Chen

A representation of frequency of strings of length K in complete genomes of many organisms in a square has led to seemingly self-similar patterns when K increases. These patterns are caused by under-represented strings with a certain &#34;tag&#34;-string and they define some fractals when K tends to infinite. The Box and Hausdorff dimensions of the limit set

Chung Wen Kao

The amplitudes of the pion electroproduction from the nucleon are derived up to third order in the chiral effective theory including explicit $Δ$(1232) >. The Q^2 evolutions of weighted integrals of amplitudes are presented.

M. Hasegawa, K. Kaneko, S. Tazaki

To study collective motion, the extended pairing plus $QQ$ force model proposed recently is applied to $A$=46, 48 and 50 nuclei in the $fp$ shell region. Exact shell model calculations in the truncated model space $(f_{7/2},p_{3/2},p_{1/2})$ prove the usefulness of the interaction. The simple model with the pairing plus quadrupole pairing plus $QQ$ force and

J. E. Amaro, T. W. Donnelly

The cross section for the reaction $^{39}\vec{\rm K}(e,e&#39;p)^{38}$Ar is computed, and the dependence of the FSI on the initial polarization angles of the nucleus $^{39}$K is analyzed. The results are explained in a semi-classical picture of the reaction. This procedure allows us to find the best initial kinematical conditions for minimizing the FSI.

Denis PERROT

We establish a general local formula computing the topological anomaly of gauge theories in the framework of non-commutative geometry.

R. F. Streater

We set up a discrete space-time dynamical model of molecules with thermalised kinetic energy and repulsive cores, in an external potential. The state is specified by a probability on the sample space. One time-step is given by a bistochastic map, followed by a local thermalising map. The model obeys the first and second laws of thermodynamics. The continuum

R. F. Streater

Let H be a self-adjoint operator such that exp(-aH) is of trace class for some a<1. Let V be a symmetric operator, Kato bounded relative to H. We show that log Tr[exp(-H+xV)] is a real analytic function of x in a hood of x=0. We show that the Gibbs states of H+xV form a real analytic Banach manifold. This work has been extended in math-ph/9910031.

R. F. Streater

We construct a Banach manifold of states, which are Gibbs states for potentials that are form-bounded in the sense of Kato relative to the free Hamiltonian. We construct the (+1)-affine structure and the (+1)-affine connection in the sense of Amari.

Gary Gruenhage

We obtain several results and examples concerning the general question ``When must a space with a small diagonal have a G_delta-diagonal?&#34;. In particular, we show (1) every compact metrizably fibered space with a small diagonal is metrizable; (2) there are consistent examples of regular Lindelof (even hereditarily Lindelof) spaces with a small diagonal b

J. I. Farran

The number A(q) shows the asymptotic behaviour of the quotient of the number of rational points over the genus of non-singular absolutely irreducible curves over a finite field Fq. Research on bounds for A(q) is closely connected with the so-called asymptotic main problem in Coding Theory. In this paper, we study some generalizations of this number for non-i

Simon Scott

We compute the relative zeta-function metric on the determinant line bundle for a family of elliptic boundary value problems of Dirac-type. To do this we prove a general formula relating the zeta-determinant to a Fredholm determinant over the boundary for a class of higher-order elliptic boundary value problems.

E. Buffenoir, Ph. Roche

We study the tensor product of principal unitary representations of the quantum Lorentz group, prove a decomposition theorem and compute the associated intertwiners. We show that these intertwiners can be expressed in terms of complex continuations of 6j symbols of U_q(su(2)). These intertwiners are expressed in terms of q-Racah polynomials and Askey-Wilson

Kurt Johansson

Consider a realization of a Poisson process in R^2 with intensity 1 and take a maximal up/right path from the origin to (N,N) consisting of line segments between the points, where maximal means that it contains as many points as possible. The number of points in such a path has fluctuations of order N^chi, where chi=1/3 by a result of Baik-Deift-Johansson. H

P. Kurlberg, Z. Rudnick

We prove a strong version of quantum ergodicity for linear hyperbolic maps of the torus (``cat maps&#39;&#39;). We show that there is a density one sequence of integers so that as N tends to infinity along this sequence, all eigenfunctions of the quantum propagator at inverse Planck constant N are uniformly distributed. A key step in the argument is to show

D. Shklyarov, S. Sinel&#39;shchikov, L. Vaksman

In our preprint q-alg/9703005 q-analogues of bounded symmetric domains were defined to be homogeneous spaces of the associated quantum groups. The investigation of a simplest among those domains, the quantum matrix ball, was started in math.QA/9803110. This work presents a construction of q-analogues for Hardy-Bergman spaces of &#39;functions in those balls&

Michael Anshelevich

We consider free multiple stochastic measures in the combinatorial framework of the lattice of all diagonals of an n-dimensional space. In this free case, one can restrict the analysis to only the noncrossing diagonals. We give definitions of what free multiple stochastic measures are, and calculate them for the free Poisson and free compound Poisson process

D. Shklyarov, S. Sinel&#39;shchikov, L. Vaksman

We proceed with studying the q-analogues of Cartan domains introduced in q-alg/9703005 and turn to the case of a ball in the space of complex matrices. An explicit expression for a positive $U_q\frak{su}_{nm}$-invariant integral (see math.QA/9803110) is used to define q-analogues for weighted Bergman spaces. The orthogonal projections onto these spaces are i

O. Lunin, S. Pinsky

In these lectures we discuss the application of discrete light cone quantization (DLCQ) to supersymmetric field theories. We will see that it is possible to formulate DLCQ so that supersymmetry is exactly preserved in the discrete approximation. We call this formulation of DLCQ, SDLCQ and it combines the power of DLCQ with all of the beauty of supersymmetry.

T. Dasgupta, B. Stefanski

There are two families of non-BPS bi-spinors in the perturbative spectrum of the nine dimensional heterotic string charged under the gauge group $SO(16)\times SO(16)$. The relation between these perturbative non-BPS states and certain non-perturbative non-BPS D-brane states of the dual type I$^\prime$ theory is exhibited. The relevant branes include a $\Zop_

P. Mayr

The study of curved D-brane geometries in type II strings implies a general relation between local singularities $\cx W$ of Calabi-Yau manifolds and gravity free supersymmetric QFT&#39;s. The minimal supersymmetric case is described by F-theory compactifications on $\cx W$ and can be used as a starting point to define minimal supersymmetric heterotic string

K. B. Alkalaev, S. L. Lyakhovich

The most general 2+1 dimensional spinning particle model is considered. The action functional may involve all the possible first order Poincare invariants of world lines, and the particular class of actions is specified thus the corresponding gauge algebra to be unbroken by inhomogeneous external fields. Nevertheless, the consistency problem reveals itself a

Mu-In Park, Jae Hyung Yee

In a recent letter, Cadoni and Mignemi proposed a formulation for the statistical computation of the 2D black holes entropy. We present a criticism about their formulation.

L. M. Baker, D. B. Fairlie

The quantum mechanical transition between a free particle Lagrangian and the Klein Gordon field description of a free particle (particle wave duality) is conjectured to extend to an analogous construction of relativistically invariant wave equations associated with strings and branes, which we propose to call brane-wave duality. Electromagnetic interactions

P. Mayr

We review a systematic construction of $\cx N=1$ supersymmetric heterotic string vacua using mirror symmetry. The method provides a large class of explicit solutions for stable, holomorphic vector bundles on Calabi-Yau n-folds Z_n in terms of toric geometry. Phenomenologically interesting compactifications as well as non-perturbative dynamics of the heteroti

Leonard Gamberg, Kimball A. Milton

We develop the quantum field theory of electron-point magnetic monopole interactions and more generally, dyon-dyon interactions, based on the original string-dependent ``nonlocal&#39;&#39; action of Dirac and Schwinger. We demonstrate that a viable nonperturbative quantum field theoretic formulation can be constructed that results in a string {\em independen

Silas R. Beane

New constraints on resonance saturation in chiral perturbation theory are investigated. These constraints arise because each consistent saturation scheme must map to a representation of the full QCD chiral symmetry group. The low-energy constants of chiral perturbation theory are then related by a set of mixing angles. It is shown that vector meson dominance

J. Gasser, V. E. Lyubovitskij, A. Rusetsky

We propose a non relativistic effective Lagrangian approach to study hadronic atom observables in the framework of QCD (including photons). We apply our formalism to derive a general expression for the width of the pi+pi- atom decaying into two neutral pions. It contains all terms at leading and next-to-leading order in isospin breaking. The result allows on

M. Benayoun, S. I. Eidelman, V. N. Ivanchenko, Z. K. Silagadze

The process of hard photon emission by initial electrons (positrons) at B-factories is discussed. It is shown that studies of the bottomonium spectroscopy will be feasible for the planned integrated luminosity of the B-factory experiments.

Michael E. Peskin

I review the most important objectives of the physics program of a next-generation e+e- linear collider. (Introductory theory lecture presented at the 1999 International Workshop on Linear Colliders, Sitges, Barcelona, Spain.)

Michael E. Peskin

I review the array of event generators which have been written to provide simulations of high-energy e+e- reactions. (Session summary talk presented at the 1999 International Workshop on Linear Colliders, Sitges, Barcelona, Spain.)