February 1996 arXiv papers — page 8

Lian Zheng, S. Das Sarma

Motivated by a recent tunneling experiment in a double quantum-well system, which reports an anomalously enhanced electronic scattering rate in a clean two-dimensional electron gas, we calculate the inelastic quasiparticle lifetime due to electron-electron interaction in a single loop dynamically screened Coulomb interaction within the random-phase-approxima

H. S. Brandi, Belita Koiller, Eduardo R. Mucciolo

We study the electronic band structure for a model one-dimensional periodic potential in the presence of a spacially homogeneous laser field. The statistical properties of the energy bands depend on the coupling between the crystal and the laser field, going from Poisson to Wigner-Dyson (GOE) and back to Poisson as the coupling increases. We argue that the c

Ziv Hermon, Eshel Ben-Jacob, Gerd Schön

We study a 1-D array of Josephson coupled superconducting grains with kinetic inductance which dominates over the Josephson inductance. In this limit the dynamics of excess Cooper pairs in the array is described in terms of charge solitons, created by polarization of the grains. We analyze the dynamics of these topological excitations, which are dual to the

Jens Jensen

The tendency for the period of the helically ordered moments in holmium to lock into values which are commensurable with the lattice is studied theoretically as a function of temperature and magnetic field. The commensurable effects are derived in the mean-field approximation from numerical calculations of the free energy of various commensurable structures,

Andrei Goryachev, Raymond Kapral

Spiral waves are investigated in chemical systems whose underlying spatially-homogeneous dynamics is governed by a deterministic chaotic attractor. We show how the local periodic behavior in the vicinity of a spiral defect is transformed to chaotic dynamics far from the defect. The transformation occurs by a type of period doubling as the distance from the d

W. Van Dyke Dixon, Arthur F. Davidsen, Ben Dorman, Harry Ferguson

The globular cluster M79 was observed with the Hopkins Ultraviolet Telescope (HUT) during the Astro-1 space shuttle mission in 1990 December. The cluster's far-UV integrated spectrum shows strong absorption in the Lyman lines of atomic hydrogen. We seek to use this spectrum, together with optical photometry, to constrain the stellar mass distribution alo

Alexei Kritsuk

An equilibrium model is presented for a hydrostatic isothermal hot gas distribution in a gravitational well of a giant elliptical galaxy immersed in a massive dark halo. The self-consistently determined gravitational potential of the system provides the optical surface brightness distribution of the galaxy, matching the de Vaucouleurs R^1/4-law, if the sound

D. Grasso, H. R. Rubinstein

In view of several conflicting results, we reanalyze the effects of magnetic fields on the primordial nucleosynthesis. In the case the magnetic field is homogeneous over a horizon volume, we show that the main effects of the magnetic field are given by the contribution of its energy density to the Universe expansion rate and the effect of the field on the el

Simon D. M. White

I review the theory of hierarchical clustering, starting with an historical overview and moving on to a discussion of those aspects of dissipationless clustering under gravity which are most relevant to galaxy formation. I conclude with some comments on the additional problems which arise when including all the other physics needed to build a realistic pictu

Matthias Bartelmann

Navarro, Frenk, \& White have recently found numerically that the density profile of dark-matter halos can be described by a universal two-parameter function over a broad range of halo masses. The profile is singular, approaching the halo center with $ρ\propto r^{-1}$. It had been argued previously that radially distorted, gravitationally lensed images of ba

R. B. Palmer, A. Sessler, A. Skrinsky, A. Tollestrup

Muon Colliders have unique technical and physics advantages and disadvantages when compared with both hadron and electron machines. They should thus be regarded as complementary. Parameters are given of 4 TeV and 0.5 TeV high luminosity \mumu colliders, and of a 0.5 TeV lower luminosity demonstration machine. We discuss the various systems in such muon colli

D. Kutasov, E. Martinec

The target space theory of the N=(2,1) heterotic string may be interpreted as a theory of gravity coupled to matter in either $1+1$ or $2+1$ dimensions. Among the target space theories in $1+1$ dimensions are the bosonic, type II, and heterotic string world sheet field theories in a physical gauge. The $2+1$ dimensional version describes a consistent quantum

N. V. Krasnikov

We construct SUSY $SU(3) \otimes SU(2)_{L} \otimes U(1)$ electroweak models with superweak R-parity. The scale of R-parity violation in one of the models is determined by the Majorana mass of neutrino and it is very small that leads to the existence of longlived ($ T \geq O(10^{-4}sec$) lightest superparticle. If lightest superparticle is righthanded charged

Antonio Coniglio, Hans Herrmann

We describe the contact network of granular packings by a frustrated lattice gas that contains steric frustration as essential ingredient. Two transitions are identified, a spin glass transition at the onset of Reynolds dilatancy and at lower densities a percolation transition. We describe the correlation functions that give rise to the singularities and pro

Takuya Okabe

Keeping nickel, cobalt and iron in mind, we investigate the origin of the itinerant ferromagnetism. In so doing, we generalize the Gutzwiller approximation. In that,we take account of the effect of the band degeneracy and the Hund's-rule coupling in addition to the on-site repulsion. After the discussion on nickel, the condition for the incomplete ferrom

H. J. Mo, Y. P. Jing, S. D. M. White

We show that if a sample of galaxy clusters is complete above some mass threshold, then hierarchical clustering theories for structure formation predict its autocorrelation function to be determined purely by the cluster abundance and by the spectrum of linear density fluctuations. Thus if the shape of the initial fluctuation spectrum is known, its amplitude

Joseph Polchinski, Shyamoli Chaudhuri, Clifford V. Johnson

This is a series of remedial lectures on open and unoriented strings for the heterotic string generation. The particular focus is on the interesting features that arise under T-duality---D-branes and orientifolds. The final lecture discusses the application to string duality. There will be no puns. Lectures presented by J. P. at the ITP from Nov. 16 to Dec.

Gary Horowitz, Andrew Strominger

A six-dimensional black string is considered and its Bekenstein-Hawking entropy computed. It is shown that to leading order above extremality, this entropy precisely counts the number of string states with the given energy and charges. This identification implies that Hawking decay of the near-extremal black string can be analyzed in string perturbation theo

David S. Graff, Katherine Freese

We derive mass functions (MF) for halo red dwarfs (the faintest hydrogen burning stars) and then extrapolate to place limits on the total mass of halo brown dwarfs (stars not quite massive enough to burn hydrogen). The mass functions are obtained from the luminosity function of a sample of 114 local halo stars in the USNO parallax survey (Dahn \etal 1995). W

Alan Kostelecky, Neil Russell

A mapping is obtained relating analytical radial Coulomb systems in any dimension greater than one to analytical radial oscillators in any dimension. This mapping, involving supersymmetry-based quantum-defect theory, is possible for dimensions unavailable to conventional mappings. Among the special cases is an injection from bound states of the three-dimensi

K. Funakubo, A. Kakuto, S. Otsuki, F. Toyoda

We propose a new method to evaluate the chiral charge flux, which is converted into baryon number in the framework of the charge transport scenario of electroweak baryogenesis. By the new method, one can calculate the flux in the background of any type of bubble wall with any desired accuracy.

M. Yoshimura

A new theory of thermal history after inflation is outlined by taking into account the effect of parametric resonance caused by inflaton oscillation. A typical outcome is existence of a high temperature phase, that makes possible GUT baryogenesis consistently with low enough gravitino abundance.

Jens Siewert, Gerd Schön

Charge is transported through superconducting SSS single-electron transistors at finite bias voltages by a combination of coherent Cooper-pair tunneling and quasiparticle tunneling. At low transport voltages the effect of an ``odd'' quasiparticle in the island leads to a $2e$-periodic dependence of the current on the gate charge. We evaluate the $I-V

N. Gurappa, Prasanta. K. Panigrahi

An operator method is provided to generate an explicit set of complete eigenfunctions for the Calogero-Sutherland model, obtained earlier by Vacek, Okiji and Kawakami, through a special ansatz. We find the connection of the above basis set with the general eigenfunctions of this model and explicitly show that these states describe {\it only} the center of ma

Ivan Gjaja

In a comment on the paper of Habib and Ryne, chao-dyn/9406010 and Phys.Rev.Lett. vol.74, 70 (1995), I point out that the Iwasawa decomposition of the symplectic group can be used to write down closed-form expressions for the noncompact part of the group and thus to compute the Lyapunov exponents in systems with more than two degrees of freedom using the cite

Michael S. Turner, James W. Truran, David N. Schramm, Craig J. Copi

Deuterium plays a crucial role in testing big-bang nucleosynthesis. Its chemical evolution, while simple (it is burned to $^3$He), is intertwined with the more complicated evolution of $^3$He. Gloeckler \& Geiss' new measurement of the $^3$He abundance and the HST measurement of D, both in the local ISM today, can be compared to the pre-solar nebula abun

Gregory M. Harry, Thomas R. Stevenson, Ho Jung Paik

We have calculated signal-to-noise ratios for eight spherical resonant-mass antennas interacting with gravitational radiation from inspiralling and coalescing binary neutron stars and from the dynamical and secular bar-mode instability of a rapidly rotating star. We find that by using technology that could be available in the next several years, spherical an

Steven Bradlow, Oscar Garcia-Prada

The Seiberg-Witten equations are defined on certain complex line bundles over smooth oriented four manifolds. When the base manifold is a complex Kahler surface, the Seiberg-Witten equations are essentially the Abelian vortex equations. Using known non-abelian generalizations of the vortex equations as a guide, we explore some non-abelian versions of the Sei

Elizabeth H. Simmons, Yumian Su

We compute the one-loop corrections to the $Z \to b\bar{b}$ vertex in the $U(1)_R$ symmetric minimal supersymmetric extension of the standard model. We find that the predicted value of $R_b$ is consistent with experiment if the mass of the lighter top squark is no more than 180 GeV. Furthermore, other data combines to place a lower bound of 88 GeV on the mas

Michael C. Birse

The contribution of nucleons to the quark condensate in nuclear matter includes a piece of first order in $m_π$, arising from the contribution of low-momentum virtual pions to the $πN$ sigma commutator. Chiral symmetry requires that no term of this order appears in the $NN$ interaction. The mass of a nucleon in matter thus cannot depend in any simple way on

Jun Li, Gang Tian

We introduce a method of constructing the virtual cycle of any scheme associated with a tangent-obstruction complex. We apply this method to constructing the virtual moduli cycle of the moduli of stable maps from n-pointed genus g curves to any smooth projective variety. As an application, we give an algebraic definition of GW-invariants for any smooth proje

Keith R. Dienes

This is a pedagogical review article surveying the various approaches towards understanding gauge coupling unification within string theory. As is well known, one of the major problems confronting string phenomenology has been an apparent discrepancy between the scale of gauge coupling unification predicted within string theory, and the unification scale exp

Curtis G. Callan, Juan M. Maldacena

Strominger and Vafa have used D-brane technology to identify and precisely count the degenerate quantum states responsible for the entropy of certain extremal, BPS-saturated black holes. Here we give a Type-II D-brane description of a class of extremal {\it and} non-extremal five-dimensional Reissner-Nordström solutions and identify a corresponding set of de

Anton Kapustin, Zoltan Ligeti, Mark B. Wise, Benjamin Grinstein

Comparing the result of inserting a complete set of physical states in a time ordered product of $b$ decay currents with the operator product expansion gives a class of zero recoil sum rules. They sum over physical states with excitation energies less than $Δ$, where $Δ$ is much greater than the QCD scale and much less than the heavy charm and bottom quark m

Pawel O. Mazur

The present paper proposes a basis for new gravitational mechanics. The problem of finding the spectrum of mass-energy is reduced to a new kind of eigenvalue problem which intrinsically contains the fundamental length ${\it l} = \sqrt{Gh\over c^3}$.The new wave equations are difference wave equations in one representation of the theory.

Euan Squires

The reason why orthodox quantum theory necessarily invokes consciousness is explained. Several procedures whereby the Born probability rule can be introduced are discussed, and reasons are given for prefering one in which consciousness selects a unique realised world. Consciousness is something outside of the laws of physics (quantum mechanics), but it has a

R. Barbier, M. Kibler

A two-parameter quantum algebra $U_{qp}({\rm u}_2)$ is briefly investigated in this paper. The basic ingredients of a model based on the $U_{qp}({\rm u}_2)$ symmetry, the $qp$-rotator model, are presented in detail. Some general tendencies arising from the application of this model to the description of rotational bands of various atomic nuclei are summarize

Fermin Aldabe

In systems with constraints, physical states must be annihilated by the constraints. We make use of this rule to construct physical asymptotic states in the Skyrme model. The standard derivation of the Born terms with asymptotic physical states shows that there is no Yukawa coupling for the Skyrmion. We propose a remedy tested in other solitonic models: A Wi

Siqi Fu, A. V. Isaev, Steven G. Krantz

We give, in dimensions three or greater, an example of a bounded, pseudoconvex, circular domain in complex space with smooth real analytic boundary and non-compact automorphism group which is not biholomorphically equivalent to any Reinhardt domain. We give an analogous example in dimension two, but the domain fails to be smooth at one boundary point---indee

F T Brandt, D G C McKeon

It has been shown how on-shell forward scattering amplitudes (the ``Barton expansion'') and quantum mechanical path integral (QMPI) can both be used to compute temperature dependent effects in thermal field theory. We demonstrate the equivalence of these two approaches and then apply the QMPI to compute the high temperature expansion for the four-poi

D. M. Gitman, I. V. Tyutin

Pseudoclassical supersymmetric model to describe massive particles with higher spins (integer and half-integer) in $2+1$ dimensions is proposed. The quantization of the model leads to the minimal (with only one polarization state) quantum theory. In particular, the Bargmann-Wigner type equations for higher spins arise in course of the canonical quantization.

H. Reinhardt

The conventional path integral expression for the Yang-Mills transition amplitude with flat measure and gauge-fixing built in via the Faddeev-Popov method has been claimed to fall short of guaranteeing gauge invariance in the non-perturbative regime. We show, however, that it yields the gauge invariant partition function where the projection onto gauge invar

John D. Smith, David J. Toms

We examine Bose-Einstein condensation as a form of symmetry breaking in the specific model of the Einstein static universe. We show that symmetry breaking never occursin the sense that the chemical potential $μ$ never reaches its critical value.This leads us to some statements about spaces of finite volume in general. In an appendix we clarify the relationsh

Jonathan L. Rosner

The enhancement $ΔΓ(Λ_b)$ of the $Λ_b$ decay rate due to four-fermion processes of weak scattering and Pauli interference is calculated within the quark model. An estimate of the relative $bu$ wave function at zero separation, $|Ψ(0)|^2_{bu}$, is obtained in terms of the $Σ_b^* - Σ_b$ hyperfine splitting, the $B^* - B$ hyperfine splitting, and the $B$ meson

A. Brunstein, O. J. P. Eboli, M. C. Gonzalez-Garcia

We obtain the constraints on possible anomalous quartic vector-boson vertices arising from the precision measurements at the $Z$ pole. In the framework of $SU(2)_L \otimes U(1)_Y$ chiral Lagrangians, we examine all effective operators of order $D=4$ that lead to four-gauge-boson interactions but do not induce anomalous trilinear vertices. We constrain the an

Kyungsik Kang, Sin Kyu Kang

There have been a great deal of works on the precision test of the standard model (SM) because of the incredibly precise data obtained at the LEP and the new measurements of $M_W$ and $m_t$ at the Fermilab Tevatron as well as the recent theoretical progress in the higher order radiative corrections. We will discuss some of the hidden inputs and theoretical u

Roy Maartens, Conrad Mellin

By imposing natural geometrical and kinematical conditions on a conformal Killing vector in Bianchi I spacetime, we show that a class of axisymmetric metrics admits a conformal motion. This class contains new exact solutions of Einstein's equations, including anisotropic radiation universes that isotropise at late times.

Jae-Kwon Kim, Adauto J. F. de Souza\cite{addr}, D. P. Landau

Using single cluster flip Monte Carlo simulations we accurately determine new finite size scaling functions which are expressed only in terms the variable $x = ξ_L / L$, where $ξ_L$ is the correlation length in a finite system of size $L$. Data for the d=2 and d=3 Ising models, taken at different temperatures and for different size lattices, show excellent d

K. Morawetz, G. Röpke, Max-Planck-Gesellschaft

The quantum mechanical two - particle problem is considered in hot dense nuclear matter under the influence of a strong electric field such as the field of the residual nucleus in heavy - ion reactions. A generalized Galitskii-Bethe-Salpeter equation is derived and solved which includes retardation and field effects. Compared with the in-medium properties in

K. Itai, P. Fazekas

We extend the periodic Anderson model by switching on a Hubbard $U_d$ for the conduction electrons. The nearly integral valent (Kondo) limit of the Anderson--Hubbard model is studied with the Gutzwiller variational method. The new formula for the Kondo energy contains the $U_d$-dependent chemical potential of the Hubbard subsystem in the exponent, and the co

J. Oitmaa, Rajiv R. P Singh, Zheng Weihong

We have carried out extensive series studies, at T=0 and at high temperatures, of 2-chain and 3-chain spin-half ladder systems with antiferromagnetic intrachain and both antiferromagnetic and ferromagnetic interchain couplings. Our results confirm the existence of a gap in the 2-chain Heisenberg ladders for all non-zero values of the interchain couplings. Co

Chi Au, Bao-Heng Zhao, H. T. Nieh

Making use of symmetry properties and known exact results for the Hubbard Model on bipartite lattice, we show that (1) there is no phase separation for repulsive coupling at low dopings, (2) phase separation and superconductivity co-exist in the ground states for attractive coupling in a range of filling fractions.

Stefano Lepri, Antonio Politi, Alessandro Torcini

From the analyticity properties of the equation governing infinitesimal perturbations, it is shown that all stability properties of spatially extended 1D systems can be derived from a single function that we call entropy potential since it gives directly the Kolmogorov-Sinai entropy density. Such a function allows determining also Lyapunov spectra in referen

Michael Blank, Gerhard Keller

We prove stochastic stability of chaotic maps for a general class of Markov random perturbations (including singular ones) satisfying some kind of mixing conditions. One of the consequences of this statement is the proof of Ulam's conjecture about the approximation of the dynamics of a chaotic system by a finite state Markov chain. Conditions under which

David Crampton, O. Le Fevre, F. Hammer, S. J. Lilly

Ratnatunga et al. (1995) have recently proposed that an object, HST 14176+5226, in the "Groth-Westphal" HST survey strip is an "Einstein cross" gravitational lens. By chance, this object has been previously observed in the Canada-France Redshift Survey. The candidate lens, catalogued as CFRS14.1311, is an elliptical galaxy at z = 0.81. In add

R. Cabanac, E. F. Borra

In this article we compare the cross-correlation and breakfinder techniques applied to the measurements of redshifts from low-resolution spectra. We assume spectra obtained from multinarrowband imagery, a technique for multi-object spectrophotometry. Comparing the cross-correlation with the breakfinder, we find that neither is intrinsically superior to the o

C. J. Grillmair, E. A. Ajhar, S. M. Faber, W. A. Baum

We analyze post-refurbishment Hubble Space Telescope images of four globular clusters in M31. The ability to resolve stars to below the horizontal branch permits us to use star counts to extend the surface brightness profiles determined using aperture photometry to almost 5 orders of magnitude below the central surface density. Three of the resulting cluster

Paul Goudfrooij, Eric Emsellem

In the light of the recent finding that nebular emission lines are commonly found in the inner regions of early-type galaxies, we evaluate their effect to stellar absorption-line indices. We derive analytical expressions for changes induced by the presence of nebular emission lines, both for atomic and molecular absorption-line indices. We find that the [NI]

E. Calabresu, G. Fiorentini, M. Lissia

Experimental determinations of the pp and pep fluxes have great potentialities. We briefly review the reasons that make such measurements privileged tests of neutrino properties. We discuss the predictions for these fluxes given by four good solutions to the solar neutrino problem: small- and large-angle MSW and Just-So oscillations into active neutrinos, an

R. G. Abraham, N. R. Tanvir, B. X. Santiago, R. S. Ellis

The morphological properties of galaxies between $21 {\rm~mag} < I < 25 {\rm~mag}$ in the {\em Hubble Deep Field} are investigated using a quantitative classification system based on measurements of the central concentration and asymmetry of galaxian light. The class distribution of objects in the {\em Hubble Deep Field} is strongly skewed towards highly asy

Dany Page

Witten&#39;s conjecture about strange quark matter (`Strange Matter&#39;) being the ground state of QCD at finite baryon number is presented and stars made of strange matter (`Strange Stars&#39;) are compared to neutron stars. The only observable way in which a strange star differs from a neutron star is in its early thermal history and a detailed study of s

Dany Page, Antonio Sarmiento

We complete our study of pulsars&#39; non-uniform surface temperature and of its effects on their soft X-ray thermal emission. Our previous work had shown that, due to gravitational lensing, dipolar fields cannot reproduce the strong pulsations observed in Vela, Geminga, PSR 0656+14, and PSR 1055-52. Assuming a standard neutron star mass of 1.4 Msol, we show

R. Garcia, A. Nemethi

In the last years a lot of work has been concentrated on the study of the behaviour at infinity of polynomial maps. This behaviour can be very complicated, therefore the main idea was to find special classes of polynomial maps which have, in some sense, nice properties at infinity. In this paper, we completely determine the complex algebraic monodromy at inf

W. M. Oxbury

Theta functions of level n on the principally polarised Prym varieties of an algebraic curve are dual to sections of the orthogonal theta line bundle on the moduli space of Spin(n)-bundles over the curve. As a by-product of our computations we also note that when n is odd the pfaffian line bundle on moduli space has a basis of sections labelled by the even t

J W Essam, A J Guttmann, I Jensen, D TanlaKishani

Series expansion methods are used to study directed bond percolation clusters on the square lattice whose lateral growth is restricted by a wall parallel to the growth direction. The percolation threshold $p_c$ is found to be the same as that for the bulk. However the values of the critical exponents for the percolation probability and mean cluster size are

Harold Widom

We apply an analogue of the Zakharov-Shabat dressing method to obtain infinite matrix solutions to the Toda lattice hierarchy. Using an operator transformation we convert some of these into solutions in terms of integral operators and Fredholm determinants. Others are converted into a class of operator solutions to the $l$-periodic Toda hierarchy.

Tiago Barreiro, E. J. Copeland, David H. Lyth, Tomislav Prokopec

Currently favoured extensions of the Standard Model typically contain `flaton fields&#39; defined as fields with large vacuum expectation values (vevs) and almost flat potentials. If a flaton field is trapped at the origin in the early universe, one expects `thermal inflation&#39; to take place before it rolls away to the true vacuum, because the finite-temp

Subir Sarkar

The Hubble expansion of galaxies, the $2.73\dK$ blackbody radiation background and the cosmic abundances of the light elements argue for a hot, dense origin of the universe --- the standard Big Bang cosmology --- and enable its evolution to be traced back fairly reliably to the nucleosynthesis era when the temperature was of $\Or(1)$ MeV corresponding to an

Andreas Albrecht, Benjamin D. Wandelt

Recently it has been realized that observations of fluctuations in the cosmic microwave background (CMB) can reveal very interesting information about the degree of coherence exhibited by the perturbations at early times. This fact should allow sufficiently detailed observations to clearly differentiate among several competing models of structure formation.

J. W. Bos, D. Chang, S. C. Lee, Y. C. Lin

We show that the magnetic moments of the octet baryons can be fitted to an accuracy of 1.5 percent by a phenomenological Lagrangian in which SU(3) breaking corrections appear only linearly. This is in contrast to conventional chiral perturbation theory in which corrections non-analytic in SU(3) breaking dominate and tend to spoil the agreement with the data.

Hélène Maurey, Thierry Giamarchi

We study the transport through two impurities or ``barriers&#39;&#39; in a one-dimensional quantum wire, taking into account the long-range $\frac1r$ Coulomb interactions. We compute the temperature-dependent conductance $G(T)$ of this system. Long-range forces lead to a dramatic increase of weak barrier potentials with decreasing temperature, even in the ``

Wolfdieter Lang

The spectral measure for the two families of orthogonal polynomial systems related to periodic chains with N-particle elementary unit and nearest neighbour harmonic interaction is computed using two different methods. The interest is in the orthogonal polynomials related to Fibonacci chains in the periodic approximation. The relation of the measure to approp

J. C. J. Paasschens, T. Sh. Misirpashaev, C. W. J. Beenakker

We study the propagation of radiation through a disordered waveguide with a complex dielectric constant $ε$, and show that dual systems, which differ only in the sign of the imaginary part of $ε$, have the same localization length. Paradoxically, absorption and stimulated emission of radiation suppress the transmittance of the waveguide in the same way.

Carlo Presilla, Johannes Sjöstrand

An adiabatic approximation in terms of instantaneous resonances is developed to study the steady-state and time-dependent transport of interacting electrons in biased resonant tunneling heterostructures. The resulting model consists of quantum reservoirs coupled to regions where the system is described by nonlinear ordinary differential equations and has a g

Daniel C. Cabra, Gerardo L. Rossini

We show that gauge invariant composites in the fermionic realization of $SU(N)_1$ conformal field theory explicitly exhibit the holomorphic factorization of the corresponding WZW primaries. In the $SU(2)_1$ case we show that the holomorphic sector realizes the spinon $Y(sl_2)$ algebra, thus allowing the classification of the chiral Fock space in terms of sem

T. Fülöp

The Schrödinger-type formalism of the Klein-Gordon quantum mechanics is adapted for the case of the $SL(2,\R)$ spacetime. The free particle case is solved, the results of a recent work are reproduced while all the other, topologically nontrivial solutions and the antiparticle modes are also found, and a deeper insight into the physical content of the theory

Jose F. Cariñena, J. Nasarre

Geometric optics is analysed using the techniques of Presymplectic Geometry. We obtain the symplectic structure of the space of light rays in a medium of a non constant refractive index by reduction from a presymplectic structure, and using adapted coordinates, we find Darboux coordinates. The theory is illustrated with some examples and we point out some si

Priyamvada Natarajan, Jean-Paul Kneib

We propose a new approach to study the dynamical implications of mass models of clusters for the velocity structure of galaxies in the core. Strong and weak lensing data are used to construct the total mass profile of the cluster, which is used in conjunction with the optical galaxy data to solve in detail for the nature of galaxy orbits and the velocity ani

Gardo Garnet Blado

The ring-shaped Hartmann potential $ V = ησ^{2} ε_{0} \left( \frac{2 a_{0}}{r} - \frac{ηa_{0}^{2}}{r^{2} sin^{2} θ} \right) $ was introduced in quantum chemistry to describe ring-shaped molecules like benzene. In this article, the supersymmetric features of the Hartmann potential are discussed. We first review the results of a previous paper in which we rede

Marc-Thierry Jaekel, Serge Reynaud

Clock synchronisation relies on time-frequency transfer procedures which involve quantum fields. We use the conformal symmetry of such fields to define as quantum operators the time and frequency exchanged in transfer procedures and to describe their transformation under transformations to inertial or accelerated frames. We show that the classical laws of re

Alexander Turbiner

Certain non-linear relations between the generators of the (q-deformed) Heisenberg algebra are found. Some of these relations are invariant under quantization and $q$-deformation.

Omar Foda, Kailash C. Misra, Masato Okado

We characterize, in the case of affine sl(2), the crystal base of the Demazure module E_w(\La) in terms of extended Young diagrams or paths for any dominant integral weight \La and Weyl group element w. Its character is evaluated via two expressions, &#39;bosonic&#39; and &#39;fermionic&#39;.

S. Garoufalidis

Using elementary counting methods of weight systems for finite type invariants of knots and integral homology 3-spheres, in the spirit of [B-NG], we answer positively three questions raised in [Ga]. In particular, we exhibit a one-to-one map from the space of finite type invariants of integral homology 3-spheres to the space of finite type invariants of knot

Michael C. Birse

The role of the quark condensate in low-energy QCD and its behaviour in nuclear matter are discussed. Partial restoration of chiral symmetry, as indicated by a reduction of the quark condensate in matter, could significantly alter the properties of nucleons and mesons. Various signals of these effects are discussed: enhancement of the axial charge of a nucle

John Smillie, Gregery T. Buzzard

These notes are the outgrowth of a series of lectures given at MSRI in January 1995 at the beginning of the special semester in complex dynamics and hyperbolic geometry. In these notes, the primary aim is to motivate the study of complex dynamics in two variables and to introduce the major ideas in the field. Hence the treatment of the subject is mostly expo

Efrain J. Ferrer, Rene Hurka, Vivian de la Incera

The screening of an applied magnetic field in the charged anyon fluid at finite density and temperature is investigated. For densities typical of high-temperature superconducting materials we find that the anyon fluid exhibits a superconducting behavior at any temperature. The total Meissner screening is characterized by two penetration lengths corresponding

Christof Wetterich

A systematic loop expansion is formulated in terms of full propagators and vertices. It is based on an expansion of the general solution of an exact non-perturbative flow equation.

Sergei Ketov

The two-dimensional manifestly locally supersymmetric actions describing the N=2 and N=4 extended super-Liouville theory coupled to the N=2 and N=4 conformal supergravity, respectively, are constructed in superspace. It is shown that the N=4 super-Liouville multiplet is described by the improved twisted-II scalar multiplet TM-II, whose kinetic terms are give

Jose F. Cariñena, J. Nasarre

The tools of presymplectic geometry are used to study light rays trajectories in anisotropic media.

S. J. Dong, J. -F. Lagaë, K. F. Liu

We report on a lattice QCD calculation of the $πN σ$ term, the scalar form factor, and $\langle N|\bar{s}s|N\rangle$. The disconnected insertion part of $\sg$ is found to be $1.8 \pm 0.1$ times larger than the connected insertion contribution. The $q^2$ dependence of $\sg(q^2)$ is about the same as $G_E(q^2)$ of the proton so that $\sg(2m_π^2) - \sg(0) = 6.6

Eric Laenen, Stephan Riemersma

Open heavy flavour production at $e^+e^-$ colliders in deeply inelastic $eγ$ scattering has an interesting feature: the structure function $F_2(x,Q^2)$ for this process is calculable for $x>0.01$, and is essentially proportional to the gluon density in the photon for smaller $x$ values. We give estimates for event rates at LEP2 and a Next Linear Collider in

V. Kartvelishvili, R. Kvatadze

The use of an unfolding procedure is proposed as an alternative method of extracting the $W$ boson mass from the data measured at LEP2, which may improve the accuracy of this measurement. The benefits of the direct unfolding method based on the Singular Value Decomposition of the response matrix are demonstrated on the example of W mass determination from th

M. B. Voloshin

The perturbative QCD corrections to the nonleptonic decay rate of the $b$ quark are discussed. By considering the limit where the final charmed quarks are slow, it is argued that the coefficients of the $α_s^2$ terms, corresponding to next-to-next-to-leading order in the standard renormalization group expansion in $\ln (m_W/m_b)$, are naturally large. The la

H. Leutwyler

Talk given at the Conference on Fundamental Interactions of Elementary Particles, ITEP, Moscow, Oct. 1995. The paper reviews the current status of knowledge concerning m_u, m_d and m_s. Qualitative aspects of the resulting picture for the breaking of isospin and eightfold way symmetries are discussed. At a more quantitative level, the review focuses on the c

Y. Nemoto, M. Oka, M. Takizawa

We study the $η\to π^0 γγ$ decay via the quark-box diagram in the three-flavor Nambu--Jona-Lasinio model that includes the $U_A (1)$ breaking effect. We find that the $η$-meson mass, the $η\to γγ$ decay width and the $η\to π^0 γγ$ decay width are in good agreement with the experimental values when the $U_A (1)$ breaking is strong and the flavor $SU(3)$ singl

S. Kumano

Various shadowing aspects of nuclear parton distributions are discussed in a parton-model framework. We explain existing $x$ dependent data of $F_2^A/F_2^D$, then the model is applied to a flavor asymmetry $\bar u-\bar d$ in a nucleus, to shadowing in valence-quark distributions, and to nuclear dependence of $Q^2$ evolution. First, we find that a finite nucl

Massimo Campostrini, Andrea Pelissetto, Paolo Rossi, Ettore Vicari

Recently-generated long strong-coupling series for the two-point Green&#39;s functions of asymptotically free ${\rm O}(N)$ lattice $σ$ models are analyzed, focusing on the evaluation of dimensionless renormalization-group invariant ratios of physical quantities and applying resummation techniques to series in the inverse temperature $β$ and in the energy $E$

J. P. Bowes, P. D. Jarvis

The theory of the $κ$-deformed Poincare algebra is applied to the analysis of various phenomena in special relativity, quantum mechanics and field theory. The method relies on the development of series expansions in $κ^{-1}$ of the generalised Lorentz transformations, about the special-relativistic limit. Emphasis is placed on the underlying assumptions need

K. Z. Win

Efficient formulae of Ricci tensor for an arbitrary diagonal metric are presented.

Yuri N. Obukhov, Friedrich W. Hehl

We discuss the choice of the Lagrangian in the Poincaré gauge theory of gravity. Drawing analogies to earlier de Sitter gauge models, we point out the possibility of deriving the Einstein-Cartan Lagrangian {\it without} cosmological term from a {\it modified} quadratic curvature invariant of {\it topological} type.