January 1998 arXiv papers — page 17

C. A. Sackett, H. T. C. Stoof, R. G. Hulet

We consider the dynamics of a quantum degenerate trapped gas of Li-7 atoms. Because the atoms have a negative s-wave scattering length, a Bose condensate of Li-7 becomes mechanically unstable when the number of condensate atoms approaches a maximum value. We calculate the dynamics of the collapse that occurs when the unstable point is reached. In addition, w

Matthias Steinmetz

The current status of numerical simulations of the formation of galaxies is reviewed. Success and failure of modeling galaxies at low and high redshift is demonstrated using a variety of examples, such as the Tully-Fisher relation, the appearance of high-redshift galaxies and the kinematics of damped Lya systems. The relationship between the clustering prope

Eric Perlman, Paolo Padovani, Paolo Giommi, Rita Sambruna

We have undertaken a survey of archived, pointed ROSAT PSPC data for blazars by correlating the ROSAT WGACAT database with several publicly available radio catalogs, restricting our candidate list to serendipitous flat radio spectrum sources (alpha_r <= 0.70). Here we discuss our survey methods, identification procedure and first results. Our survey is found

M. Stiavelli

I present galaxy models resulting from violent relaxation in the presence of a pre-existing black hole. The models are computed by maximizing the entropy of the stellar dynamical system. I show that their properties are very similar to those of adiabatic growth models for a suitable choice of parameters. This suggests that observations of nuclear light profi

Glennys R. Farrar

Candidate astrophysical acceleration sites capable of producing the highest energy cosmic rays (E > 10^{19.5} eV) appear to be at far greater distances than is compatible with their being known particles. The properties of a new particle which can account for observations are discussed and found to be tightly constrained. In order to travel 100&#39;s or 1000

Giacomo Giampieri

The existence of a large number of asymmetric, rotating neutron stars, each individually emitting periodic or quasi-periodic gravitational waves in the frequency band around 100 Hz, raises the possibility of detecting their combined signals, by exploiting the amplitude modulation of the received waves as the antenna changes its orientation with respect to fi

Rudy Wijnands, Michiel van der Klis, Mariano Mendez, Jan van Paradijs

We discovered a single kHz quasi-periodic oscillation (QPO) near 1150 Hz in the Rossi X-ray Timing Explorer X-ray light curve of the low mass X-ray binary and atoll source 4U 1735-44. The rms amplitude of this peak was 2-3%, and the FWHM 6-40 Hz. There are indications that the kHz QPO frequency decreased from 1160 Hz to 1145 Hz when the count rate increased,

John Scalo

A survey of results concerning the IMF derived from star counts is presented, including work up to, but not including, that presented in these proceedings. The situation regarding low-mass stars in the field and in clusters, high-mass stars and intermediate-mass stars in clusters and associations of the Milky Way and LMC, pre-main sequence objects in visible

Nathan Berkovits

Using the conformal compensator superfields of N=2 D=4 supergravity, the Type IIB S-duality transformations are expressed as a linear rotation which mixes the compensator and matter superfields. The classical superspace action for D=4 compactifications of Type IIB supergravity is manifestly invariant under this transformation. Furthermore, the introduction o

Shigeki Matsutani

Recently I proposed a new calculation scheme of a partition function of an immersion object using path integral method and theory of soliton (to appear in J.Phys.A). I applied the scheme to problem of elastica in two-dimensional space and Willmore surface in three dimensional space. In this article, I will apply the scheme to elastica in three dimensional sp

Shigeki Matsutani

In the previous report (J. Phys. A (1997) 30 4019-4029), I showed that the Dirac operator defined over a conformal surface immersed in R^3 is identified with the Dirac operator which is generalized the Weierstrass- Enneper equation and Lax operator of the modified Novikov-Veselov (MNV) equation. In this article, I determine the Dirac operator defined over a

J. Finkelstein

Macroscopic objects appear to have definite positions. In a many-worlds interpretation of quantum theory, this appearance is an illusion; the correct view is the &#34;view from outside&#34; in which even macroscopic objects are in general in a superposition of different positions. In the Bohm model, objects really are in definite positions. This additional a

Bernd A. Berg

Experimentally observed violations of Bell inequalities rule out local realistic theories. Consequently, the quantum state vector becomes a strong candidate for providing an objective picture of reality. However, such an ontological view of quantum theory faces difficulties when spacelike measurements on entangled states have to be described, because time or

L. Kurth Kerr, B. C. Clark, S. Hama, L. Ray

The 5-dimensional spin-0 form of the Kemmer-Duffin-Petiau (KDP) equation is used to calculate scattering observables [elastic differential cross sections ($dσ/dΩ$), total cross sections ($σ_{Tot}$), and reaction cross sections ($σ_{Reac}$})] and to deduce $σ_{Tot}$ and $σ_{Reac}$ from transmission data for $K^+ + $ $^{6}$Li, $^{12}$C, $^{28}$Si, and $^{40}$C

Ram Brustein

A string cosmology scenario (&#34;pre-big-bang&#34;) postulates that the evolution of the Universe starts from a state of very small curvature and coupling, undergoes a long phase of dilaton-driven kinetic inflation and at some later time joins smoothly standard radiation dominated cosmological evolution, thus giving rise to a singularity free inflationary c

Michele Vendruscolo, Eytan Domany

We investigate the extent to which the commonly used standard pairwise contact potential can be used to identify the native fold of a protein. Ideally one would hope that a universal energy function exists, for which the native folds of all proteins are the respective ground states. Here we pose a much more restricted question: is it possible to find a set o

M. J. Drinkwater, M. D. Gregg

We describe a search for compact dwarf galaxies in the Fornax cluster using the FLAIR spectrograph on the UK Schmidt Telescope. We measured radial velocities of 453 compact galaxies brighter than Bt=17.3 and found seven new compact dwarf cluster members that were not classified in previous surveys as members of the cluster. These are amongst the most compact

S. I. Blinnikov

High quality spectra to be produced by SUBARU 8 meter telescope will be extremely valuable for numerous astronomical projects. Here I concentrate on two classical types of weak broad line objects -- distant supernovae and white dwarfs -- with emphasis of their importance for fundamental physics, not only for astronomy. With regard to recent results of MACHO

Edward A. Spiegel

Calculations of the stopping power of a medium lead to divergent integrals in gravitational theory as they do in the analogous electromagnetic problem. In the em case, one introduces (normally in an arbitrary manner) the Debye length as a cutoff at large distances to remove the divergence. We show here that in the Newtonian gravitational analogue the distant

Joseph Silk, Martin J. Rees

The formation of massive black holes may precede the epoch that characterises the peak of galaxy formation, as characterized by the star formation history in luminous galaxies. Hence protogalactic star formation may be profoundly affected by quasar-like nuclei and their associated extensive energetic outflows. We derive a relation between the mass of the cen

Nahum Arav, Thomas A. Barlow, Ari Laor, Wallace L. W. Sargent

We search for a direct signature of discrete &#39;&#39;clouds&#39;&#39; in the broad line region (BLR) of the Seyfert galaxy NGC 4151. For this purpose we apply cross correlation (CC) analysis to a high resolution KECK spectrum of the galaxy. No such signature is found in the data. In order for cloud models to be compatible with this result, there must be at

K. I. Kellermann, R. C. Vermeulen, J. A. Zensus, M. H. Cohen

We have used the VLBA at 15 GHz to image the structure of 132 strong compact AGN and quasars with a resolution better than one milliarcsecond and a dynamic range typically exceeding 1000 to 1. These observations were made as part of a program to investigate the sub-parsec structure of quasars and AGN and to study the changes in their structure with time. Man

S. Basak, Asit K. De

We compare the performance of the Kramers Equation Monte Carlo (KMC) Algorithm with that of the Hybrid Monte Carlo (HMC) algorithm for numerical simulations with dynamical Kogut-Susskind fermions. Using the lattice Gross-Neveu model in 2 space-time dimensions, we calculate the integrated autocorrelation time of different observables at a number of couplings

Hagen Kleinert

The lecture explains the geometric basis for the recently-discovered nonholonomic mapping principle which specifies certain laws of nature in spacetimes with curvature and torsion from those in flat spacetime, thus replacing and extending Einstein&#39;s equivalence principle. An important consequence is a new action principle for determining the equation of

A. G. Izergin, A. G. Pronko

The quantum nonrelativistic two-component Bose and Fermi gases with the infinitely strong point-like coupling between particles in one space dimension are considered. Time and temperature dependent correlation functions are represented in the thermodynamic limit as Fredholm determinants of integrable linear integral operators.

Yu. S. J, K. Toda, N. Sasa, T. Fukuyama

We study the integrable systems in higher dimensions which can be written not by the Hirota&#39;s bilinear form but by the trilinear form. We explicitly discuss about the Bogoyavlenskii-Schiff(BS) equation in (2 + 1) dimensions. Its analytical proof of multi soliton solution and a new feature are given. Being guided by the strong symmetry, we also propose a

Shyamal S. Somaroo, David G. Cory, Timothy F. Havel

We show how the basic operations of quantum computing can be expressed and manipulated in a clear and concise fashion using a multiparticle version of geometric (aka Clifford) algebra. This algebra encompasses the product operator formalism of NMR spectroscopy, and hence its notation leads directly to implementations of these operations via NMR pulse sequenc

T. Obikhod, S. Radionov

The sine-Gordon model is applied to describe the multiphonon giant resonances.

Scott Thomas

Some formal aspects of supersymmetry breaking are reviewed. The classic &#34;requirements&#34; for supersymmetry breaking include chiral matter, a dynamical superpotential, and a classical superpotential which completely lifts the moduli space. These &#34;requirements&#34; may be evaded in theories with large matter representations. The mechanisms of supersy

A. N. Mitra, R. Ramanathan

The interconnection between quantum mechanics and probabilistic classical mechanics for a free relativistic particle is derived in terms of Wigner functions (WF) for both Dirac and Klein-Gordon (K-G) equations. Construction of WF is achieved by first defining a bilocal 4-current and then taking its Fourier transform w.r.t. the relative 4-coordinate. The K-G

W. -X. Yan, S. -Q. Bao, X. -G. Zhao

Via the numerical analysis on the intraband dynamics of optically excited semiconductor superlattices, we find that time-integrated squared THz emission signals can be used for probing both dynamic localization and multi-photon resonance in the coherent regime. Competition effect between dynamic localization and photon-assisted transport has also been discus

Dipak Munshi, Adrian L. Melott

Shape dependence of higher order correlations introduces complication in direct determination of these quantities. For this reason theoretical and observational progress has been restricted in calculating one point distribution functions and related moments. Methods based on factorial moments of two point count probability distribution (cumulant correlators)

K. L. Luhman, C. W. Engelbracht, M. L. Luhman

To test the PDR model spectra under the physical conditions present in Orion, we have obtained moderate-resolution (R=3000) J-, H-, and K-band long-slit spectra of the Orion bar and Orion S regions These observations provide conclusive evidence for the PDR origin (rather than shocks) of the H_2 emission in each of these regions and demonstrate significant de

P. L. Goode, L. H. Strous, T. R. Rimmele, R. T. Stebbins

We have made high resolution observations of the Sun in which we identify individual sunquakes and see power from these seismic events being pumped into the resonant modes of vibration of the Sun. A typical event lasts about five minutes. We report the physical properties of the events and relate them to theories of the excitation of solar oscillations. We a

G. E. Volovik

The Kopnin mass and the Baym-Chandler mass of the vortex have the same origin. Both represent the mass of the normal component trapped by the vortex. The Kopnin mass of the vortex is formed by quasiparticles localized in the vicinity of the vortex. In the superclean limit it is calculated as linear response exactly in the same way as the density of the norma

Roberto A. Monetti, Javier E. Satulovsky

We improve a recently proposed dynamically driven renormalization group algorithm for cellular automata systems with one absorbing state, introducing spatial correlations in the expression for the transition probabilities. We implement the renormalization group scheme considering three different approximations which take into account correlations in the stat

Fabio Zwirner

We review some recent results on the effective interactions of a light gravitino with ordinary particles. In particular, we discuss on a simple example a novel aspect of the low-energy theorems for broken supersymmetry: in the effective lagrangian describing the goldstino couplings to matter, there are terms bilinear in the goldstino that, already at the low

C. Barbero, F. Krmpotić, A. Mariano

We discuss the contributions of higher order terms in weak Hamiltonian to the standard two-neutrino double beta decay. The formalism for the unique first forbidden transitions has been developed, and it is shown that they can alter the two-electron energy spectrum. Yet, their effect is too small to screen the detection of exotic neutrinoless double beta deca

Dao-Neng Gao, Mu-Lin Yan

In this paper, U(3)$_L\times$ U(3)$_R$ chiral theory of mesons is extended to the leading order in quark mass expansion in order to evaluate the $ρ^0-ω$ mixing. It is shown that the use of path integral method to integrate out the quark fields naturally leads to the $ρ^0-ω$ mixing vertices, and this mixing is entirely from the quark loop in this theory. The

Jinwu Ye

We reexamine the effects of long-range Coulomb interaction on the onset of superconductivity. We use the model of N complex scalar fields with the Coulomb interaction studied first by Fisher and Grinstein (FG). We find that near d=3 space dimension, the system undergoes second order phase transition if $N \ge 55.39$, but undergoes fluctuation driven first or

R. Brower, S. Chandrasekharan, U. -J. Wiese

We show that cluster algorithms for quantum models have a meaning independent of the basis chosen to construct them. Using this idea, we propose a new method for measuring with little effort a whole class of Green&#39;s functions, once a cluster algorithm for the partition function has been constructed. To explain the idea, we consider the quantum XY model a

Luca Salasnich

As pointed out by the authors of the comment quant-ph/9712046, in our paper quant-ph/9712030 we studied in detail the metastability of a Bose-Einstein Condensate (BEC) confined in an harmonic trap with zero-range interaction. As well known, the BEC with attractive zero-range interaction is not stable but can be metastable. In our paper we analyzed the role o

Nguyen Quoc Thang

This is a revision of a McMaster University preprint, with extension. In this paper we prove that over local or global fields of characteristic 0, the Corestriction Principle holds for kernel and image of all maps which are connecting maps in group cohomology and the groups of $R$-equivalences. Some related questions over arbitrary fields of characteristic 0

Bruce E. Sagan, Yeong-Nan Yeh, Ping Zhang

The Wiener index is a graphical invariant that has found extensive application in chemistry. We define a generating function, which we call the Wiener polynomial, whose derivative is a q-analog of the Wiener index. We study some of the elementary properties of this polynomial and compute it for some common graphs. We then find a formula for the Wiener polyno

Bruce E. Sagan, Ping Zhang

The generalized Euler number E_{n|k} counts the number of permutations of {1,2,...,n} which have a descent in position m if and only if m is divisible by k. The classical Euler numbers are the special case when k=2. In this paper, we study divisibility properties of a q-analog of E_{n|k}. In particular, we generalize two theorems of Andrews and Gessel about

Andreas Blass, Bruce E. Sagan

We introduce the concept of a bounded below set in a lattice. This can be used to give a generalization of Rota&#39;s broken circuit theorem to any finite lattice. We then show how this result can be used to compute and combinatorially explain the Möbius function in various examples including non-crossing set partitions, shuffle posets, and integer partition

Andreas Blass, Bruce E. Sagan

Let A be a subspace arrangement and let chi(A,t) be the characteristic polynomial of its intersection lattice L(A). We show that if the subspaces in A are taken from L(B_n), where B_n is the type B Weyl arrangement, then chi(A,t) counts a certain set of lattice points. One can use this result to study the partial factorization of chi(A,t) over the integers a

Andreas Kriegl, Peter W. Michor

Regular Lie groups are infinite dimensional Lie groups with the property that smooth curves in the Lie algebra integrate to smooth curves in the group in a smooth way (an `evolution operator&#39; exists). Up to now all known smooth Lie groups are regular. We show in this paper that regular Lie groups allow to push surprisingly far the geometry of principal b

Yu. I. Manin

The paper studies three classes of Frobenius manifolds: Quantum Cohomology (topological sigma-models), unfolding spaces of singularities (K. Saito&#39;s theory, Landau-Ginzburg models), and the recent Barannikov-Kontsevich construction starting with the Dolbeault complex of a Calabi-Yau manifold and conjecturally producing the B--side of the Mirror Conjectur

Z. Lalak, R. Poppe

We examine Jordan-Brans-Dicke theories with a linear potential for the scalar field by means of a stochastic approach. The backreaction of the scalar field fluctuations on the classical background is described. The analysis is concentrated on those values of the Jordan-Brans-Dicke parameter which predict a superinflationary pre-big-bang branch. The graceful

D. Bardin, M. Bilenky, A. Sazonov, Yu. Sedykh

Analytic formulae are derived for the complete photon energy spectrum due to QED corrections to fermion pair production in case of a limited angular acceptance for the final state fermions. After a numerical integration over the energy of non-observed photons, this corresponds to typical experimental conditions at LEP/SLC.

D. Bardin, M. Bilenky, A. Chizhov, A. Sazonov

We present the convolution integral for fermion pair production in the electroweak standard theory to order O(alpha) including also soft photon exponentiation. The result is complete in the sense that it includes initial and final state radiation and their interference. From the basic result - analytic formulae for the differential cross section - we also de

B. V. Martemyanov

The interaction of dyons in the mean field approximation is considered. The result of interaction is the mass term for dyonic field in the effective Lagrangian. Due to the mass term the profile function of dyon falls off exponentially at large distances.

Jiang Yi, Zhou Mian-Lai, Ma Wen-Gan, Han Liang

We examine the subprocess $γγ\to t\bar{c}+\bar{t}c$ at electron-positron colliders in the two-Higgs-doublet model with flavor-changing scalar couplings, where all the one-loop contribuions are considered, and the results are applicable to the whole mass range of the weakly coupled Higgs bosons. Because of the heavy top quark mass, this process is important i

László Á. Gergely, Zoltán Perjés, Mátyás Vasúth

The evolution under radiation backreaction of a binary system consisting of a black hole and a companion is studied in the limiting case when the spin of the companion is negligible compared with the spin S of the black hole. To first order in the spin, the motion of the reduced-mass particle excluding radiation effects, is characterized by three constants:

Manidipa Mitra, Haranath Ghosh, S. N. Behera

The role of electron correlation on different pairing symmetries are discussed in details where the electron correlation has been treated within the slave boson formalism. It is shown that for a pure $s$ or pure $d$ wave pairing symmetry, the electronic correlation suppresses the $s$ wave gap magnitude (as well as the $T_c$) at a faster rate than that for th

Giorgio Parisi

We review the predictions of the replica approach both for the statics and for the off-equilibrium dynamics. We stress the importance of the Cugliandolo-Kurchan off-equilibrium fluctuation-dissipation relation in providing a bridge between the statics and the dynamics. We present numerical evidence for the correctness of these relations. This approach allows

Mickael Antoni, Alessandro Torcini

A two dimensional self-gravitating Hamiltonian model made by $N$ fully-coupled classical particles exhibits a transition from a collapsing phase (CP) at low energy to a homogeneous phase (HP) at high energy. From a dynamical point of view, the two phases are characterized by two distinct single-particle motions : namely, superdiffusive in the CP and ballisti

C. Castellani, C. Di Castro, P. A. Lee

The recent experimental observation of a metal-insulator transition in two dimensions prompts a re-examination of the theory of disordered interacting systems. We argue that the existing theory permits the existence of a metallic phase and propose a number of experiments such as magnetoconductance and tunnelling in the presence of a parallel field, which sho

A. F. Ho, P. Coleman

We study a lattice model for Marginal Fermi liquid behavior, involving a gas of electrons coupled to a dense lattice of three-body bound-states. The bound-states change the phase space for electron-electron scattering and induce a marginal self-energy amongst the electron gas. When the three-body bound-states are weakly coupled to the electron gas, there is

Giovanni Gallavotti, Guido Gentile, Vieri Mastropietro

Interacting systems consisting of two rotators and a point mass near a hyperbolic fixed point are considered, in a case in which the uncoupled systems have three very different characteristic time scales. The abundance of quasi periodic motions in phase space is studied via the Hamilton-Jacobi equation. The main result, a high density theorem of invariant to

G. Lamer, S. J. Wagner

Mrk 501 has been in a state of very high flux in X-rays and VHE gamma-rays during 1997. In July 1997 near its hitherto maximum X-ray brightness intense multifrequency observations of Mrk 501 have been performed at radio, near infrared, optical, X-ray, and VHE gamma-ray frequencies. Here we report on Rossi X-ray Timing Explorer (RXTE) observations carried out

N. Z. Scoville, A. S. Evans, N. Dinshaw, R. Thompson

We report high resolution imaging of the ultraluminous infrared galaxy Arp 220 at 1.1, 1.6, and 2.22 microns with NICMOS on the HST. The diffraction-limited images at 0.1--0.2 arcsecond resolution clearly resolve both nuclei of the merging galaxy system and reveal for the first time a number of luminous star clusters in the circumnuclear envelope. The morpho

Piero Madau

Ongoing searches for supernovae (SNe) at cosmological distances have recently started to provide a link between SN Ia statistics and galaxy evolution. In this talk I will use recent estimates of the global history of star formation to compute the theoretical Type Ia and Type II SN rates as a function of cosmic time. I will compare the predicted values with t

Esther M. Hu

Knowledge of the evolution of the low column density end of the Ly alpha forest (12.8 < log N_HI < 16.0 cm^-2) can provide substantial insight for models of structure formation and studies of the evolution of the ionizing background. Here we describe the evolution of the b values and column densities of forest clouds over the redshift range 2 < z < 4. While

Lennox L. Cowie, Esther M. Hu

We present deep narrow-band (lambda = 5390 Angstroms, delta lambda = 77 Angstroms) and multi-color observations of the Hubble Deep Field and the Hawaii Deep Field SSA22 obtained with the LRIS instrument at the Keck II 10-m telescope. It is shown that there is a substantial population of galaxies at z~3.4 which can be selected by Ly alpha emission. Comparison

Bumsig Kim

We formulated a mirror-free approach to the mirror conjecture, namely, quantum hyperplane section conjecture, and proved it in the case of nonnegative complete intersections in homogeneous manifolds. For the proof we followed the scheme of Givental&#39;s proof of a mirror theorem for toric complete intersections.

Guy D. Moore

We develop a method to compute the sphaleron rate in the electroweak broken phase nonperturbatively. The rate is somewhat slower than a perturbative estimate. In SU(2) X U(1) Higgs theory at the physical value of Theta_W, and assuming that the latent heat of the phase transition reheats the universe to the equilibrium temperature, baryon number erasure after

Jonathan L. Rosner

This overview of what we can hope to learn from high-statistics experiments in B physics in the next few years includes: (a) a review of parameters of the Cabibbo-Kobayashi-Maskawa (CKM) Matrix; (b) direct determination of magnitudes of CKM elements; (c) forthcoming information from studies of kaons; (d) CP violation in B decays; (e) aspects of rate measurem

Mina B. Abd-el-malek, Malak N. Makar

In this paper we discuss a theoretical model for the interfacial profiles of progressive non-linear waves which result from introducing a triangular obstacle, of finite height, attached to the bottom below the flow of a stratified, ideal, two layer fluid, bounded from above by a rigid boundary. The derived equations are solved by using a nonlinear perturbati

P. G. Estévez, Esther Conde, Pilar R. Gordoa

This paper is an attempt to present and discuss at some length the Singular Manifold Method. This Method is based upon the Painlevé Property systematically used as a tool for obtaining clear cut answers to almost all the questions related with Nonlinear Partial Differential Equations: Lax pairs, Miura, Bäcklund or Darboux Transformations as well as $τ$-funct

Maria Luz Gandarias, M. S. Bruzón

We apply the Lie-group formalism and the nonclassical method due to Bluman and Cole to deduce symmetries of the generalized Boussinesq equation, which has the classical Boussinesq equation as an special case. We study the class of functions $f(u)$ for which this equation admit either the classical or the nonclassical method. The reductions obtained are deriv

Dolan Chapa Sen, A. Roy Chowdhury

Quantization of BKP type equations are done through the Moyal bracket and the formalism of pseudo-differential operators. It is shown that a variant of the dressing operator can also be constructed for such quantized systems.

Louis Marchildon

We investigate Lie symmetries of Einstein&#39;s vacuum equations in N dimensions, with a cosmological term. For this purpose, we first write down the second prolongation of the symmetry generating vector fields, and compute its action on Einstein&#39;s equations. Instead of setting to zero the coefficients of all independent partial derivatives (which involv

Denis Blackmore, Yarema A. Prykarpatsky, Roman Samulyak

We investigate closed ideals in the Grassmann algebra serving as bases of Lie-invariant geometric objects studied before by E. Cartan. Especially, the E. Cartan theory is enlarged for Lax integrable nonlinear dynamical systems to be treated in the frame work of the Wahlquist Estabrook prolongation structures on jet-manifolds and Cartan-Ehresmann connection t

Rémi Léandre

We study the differential forms over the frame bundle of the based loop space. They are stochastics in the sense that we put over this frame bundle a probability measure. In order to understand the curvatures phenomena which appear when we look at the Lie bracket of two horizontal vector fields, we impose some regularity assumptions over the kernels of the d

Wilhelm Fushchych, Zoya Symenoh, Ivan Tsyfra

We study symmetry properties of the Schrödinger equation with the potential as a new dependent variable, i.e., the transformations which do not change the form of the class of equations. We also consider systems of the Schrödinger equations with certain conditions on the potential. In addition we investigate symmetry properties of the equation with convectio

Ezra Getzler

In Part 1 of this paper, we study gravitational descendents of Gromov-Witten invariants for general projective manifolds, applying the Behrend-Fantechi construction of the virtual fundamental classes. In Part 2, we calculate the topological recursion relations in genus 2. There are two of these, one for the second descendent of a field, and one for the first

S. E. Konstein

It is shown that the superalgebra of observables of the rational Calogero model based on the root system of I_2(n) type possesses [(n+1)/2] supertraces. Model with three-particle interaction based on the root system G_2 belongs to this class of models and its superalgebra of observables has 3 independent supertraces.

Karl Landsteiner, Esperanza Lopez, David A. Lowe

Using a six-orientifold on top of a NS-fivebrane we construct a chiral N=1 supersymmetric gauge theory in four dimensions with gauge group SU(N_c) and matter in the symmetric, antisymmetric and (anti)fundamental representations. Anomaly cancellation is fulfilled by the requirement of a smooth RR 7-form charge distribution and leads us to the introduction of

V. G. Kiselev, Ya. M. Shnir

The motion of a one-dimensional kink and its energy losses are considered as a model of interaction of nontrivial topological field configurations with external fields. The approach is based on the calculation of the zero modes excitation probability in the external field. We study in the same way the interaction of the t&#39;Hooft-Polyakov monopole with wea

Carl E. Carlson, Nimai C. Mukhopadhyay

We investigate the relations between the spin structure functions in the scaling and resonance regions. We examine the possible duality between the two, and draw inferences for the behavior of the asymmetry A_1 at large x. Finally, we point out the importance of additional polarized structure function data in the resonance region in terms of testing the hyst

K. K. Sharma, R. C. Verma

We study two-body weak hadronic decays of ψand Upsilon employing the factorization scheme. Branching ratios for ψ-> PP/PV and Υ-> PP/PV decays in the Cabibbo-angle-enhanced and Cabibbo-angle-suppressed modes are predicted.

T. Pradhan

In continuation of our model of composite electron, its companion neutrinos, photon and electro-weak gauge bosons as well as their super-partners based on extended Lorentz group $SU(3)\otimes SU(3)$ in (8+1) dimensional space-time, we show that the remaining leptons, quarks, lepto-quarks and gluons as well as their respective super-partners can be considered

Erez Etzion

High precision experimental new electroweak results measured at the four LEP experiments and the SLD collaboration are discussed. Heavy quark (b b-bar and c c-bar) forward-backward asymmetries measured at LEP are presented along with polarized forward-backward and left-right asymmetries measured at SLD. The results are compared, and the combined averages are

Erez Etzion

Some experimental new Electroweak physics results measured at the LEP/SLD and the TEVATRON are discussed. The excellent accuracy achieved by the experiments still yield no significant evidence for deviation from the Standard Model predictions, or signal to physics beyond the Standard Model. The Higgs particle still has not been discovered and a low bound is

Shahar Hod, Tsvi Piran

We study analytically the initial value problem for a charged massless scalar-field on a Reissner-Nordström spacetime. Using the technique of spectral decomposition we extend recent results on this problem. Following the no-hair theorem we reveal the dynamical physical mechanism by which the charged hair is radiated away. We show that the charged perturbatio

J. Engelfriet

An important characteristic of many logics for Artificial Intelligence is their nonmonotonicity. This means that adding a formula to the premises can invalidate some of the consequences. There may, however, exist formulae that can always be safely added to the premises without destroying any of the consequences: we say they respect monotonicity. Also, there

G. Gogic, C. H. Papadimitriou, M. Sideri

Approximating a general formula from above and below by Horn formulas (its Horn envelope and Horn core, respectively) was proposed by Selman and Kautz (1991, 1996) as a form of ``knowledge compilation,&#39;&#39; supporting rapid approximate reasoning; on the negative side, this scheme is static in that it supports no updates, and has certain complexity drawb

Shay Wolfling, Yacov Kantor

The ground state of randomly charged polyampholytes is conjectured to have a structure similar to a necklace, made of weakly charged parts of the chain, compacting into globules, connected by highly charged stretched `strings&#39;. We suggest a specific structure, within the necklace model, where all the neutral parts of the chain compact into globules: The

V. N. Kotov, J. Oitmaa, O. Sushkov

The two-dimensional quantum Heisenberg antiferromagnet at zero temperature with two kinds of locally frustrating defects - isolated ferromagnetic bonds and impurity spins, is studied. For a quantum spin, coupled antiferromagnetically to the two sublattices, we find a local ground state transition. In the case of a ferromagnetic bond, the local magnetization

Patricia A Whitelock

After a brief review of our current understanding of Miras and their evolutionary status, three aspects of ``real-time&#39;&#39; evolution in these and related stars are examined: # Chemical changes (O-rich to C-rich) due to third dredge-up # Period changes due to the effects of the helium-shell flash # The existence of ``fossil&#39;&#39; dust and gas shells

Tsvi Piran

Gamma-ray bursts (GRBs) have puzzled astronomers since their accidental discovery in the sixties. The BATSE detector on the COMPTON-GRO satellite has been detecting one burst per day for the last six years. Its findings have revolutionized our ideas about the nature of these objects. They have shown that GRBs are at cosmological distances. This idea was acce

Jonathan E. Grindlay

One of the few remaining astronomical bands (factor of $\sim$10 in energy range) still without an all-sky imaging survey is the hard x-ray band (10-600 keV). This is in spite of sensitive imaging all-sky surveys already conducted at soft x-ray energies (0.2-2 keV; ROSAT) and soft/hard $γ$-ray ($\sim$750 keV - 10 GeV; COMPTEL/EGRET) energies and imminent for

J. E. Grindlay, T. A. Prince, F. Harrison, N. Gehrels

The hard x-ray (10-600 keV) sky is inherently time variable and yet has neither been surveyed nor monitored with a sensitive imaging telescope. The Energetic X-ray Imaging Survey Telescope (EXIST) is a mission concept, proposed for MIDEX, which would conduct the first imaging all-sky hard x-ray survey as well as provide a sensitive all sky monitor. With $\si

Jun Li, Gang Tian

We show that the algebraic and the symplectic GW-inivariants of smooth projective varieties are equivalent.