November 1994 arXiv papers — page 11

Hai-Yang Cheng, B. Tseng

The $\b$ decay does not receive any nonspectator contributions and hence its theoretical calculation is relatively clean. Two different methods are employed for the study of $\b$. In the first method, both $b$ and $s$ quarks are treated as heavy and leading $1/m_s$ as well as $1/m_b$ corrections are included. The branching ratio and the asymmetry parameter $

Maarten F. L. Golterman

The quenched approximation for QCD is, at present and in the foreseeable future, unavoidable in lattice calculations with realistic choices of the lattice spacing, volume and quark masses. In these lectures, I review the analytic study of the effects of quenching based on chiral perturbation theory. Quenched chiral perturbation theory leads to quantitative i

T. Blum, Carleton DeTar, Urs M. Heller, Leo Karkkainen

We study the thermal phase diagram of pure SU(3) gauge theory with fundamental and adjoint couplings. We improve previous estimates of the position of the bulk transition line and determine the thermal deconfinement transition lines for $N_t=2,4,6,$ and 8. For $N_t > 4$ the deconfinement transition line splits cleanly away from the bulk transition line. With

John W. Barrett, Mark Galassi, Warner A. Miller, Rafael D. Sorkin

The role of Regge calculus as a tool for numerical relativity is discussed, and a parallelizable implicit evolution scheme described. Because of the structure of the Regge equations, it is possible to advance the vertices of a triangulated spacelike hypersurface in isolation, solving at each vertex a purely local system of implicit equations for the new edge

Benedetto Piccoli

This paper is concerned with a class of time-optimal control problems for the swing and the ski. We first consider the motion of a man standing on a swing. For simplicity, we neglect friction and air resistance and assume that the mass of the swinger is concentrated in his baricenter $B$. For the ski, we use the model considered by Aldo Bressan (1991), with

Graziano Crasta

We consider a class of one--dimensional non--convex non--coercive problems in the Calculus of Variations. We prove an existence result for this class of problems using a Liapunov type theorem on the range of non--atomic measures.

H. Mathur, M. Gokcedag, A. Douglas Stone

We investigate the spin-magnetism of mesoscopic metallic grains. In the average response of an ensemble of grains there are corrections to macroscopic behaviour due to both spectral fluctuations and electron-electron interactions. These corrections are a non-linear function of the magnetic field. Their temperature dependence is calculated numerically and ana

P. J. Forrester

It is shown how the universal correlation function of Brezin and Zee, and Beenakker, for random matrix ensembles of Wigner-Dyson type with density support on a finite interval can be derived using a linear response argument and macroscopic electrostatics. The analogous formula for ensembles of unitary random matrices is derived using the same method, and the

H. Rieger

We review recent numerical progress in the study of finite dimensional strongly disordered magnetic systems like spin glasses and random field systems. In particular we report in some details results for the critical properties and the non-equilibrium dynamics of Ising spin glasses. Furthermore we present an overview over recent investigations on the random

Christine Doran, B. Srinivas

A number of researchers have noted the similarities between LTAGs and CCGs. Observing this resemblance, we felt that we could make use of the wide-coverage grammar developed in the XTAG project to build a wide-coverage CCG. To our knowledge there have been no attempts to construct a large-scale CCG parser with the lexicon to support it. In this paper, we des

Tilman Becker, Owen Rambow

We present a parsing algorithm with polynomial time complexity for a large subset of V-TAG languages. V-TAG, a variant of multi-component TAG, can handle free-word order phenomena which are beyond the class LCFRS (which includes regular TAG). Our algorithm is based on a CYK-style parser for TAGs.

Anthony Kroch, Owen Rambow

We discuss two constructions (long scrambling and ECM verbs) which challenge most syntactic theories (including traditional TAG approaches) since they seem to require exceptional mechanisms and postulates. We argue that these constructions should in fact be analyzed in a similar manner, namely as involving a verb which selects for a ``defective'' com

Christy Doran, Dania Egedi, Beth Ann Hockey, B. Srinivas

XTAG is an ongoing project to develop a wide-coverage grammar for English, based on the Feature-based Lexicalized Tree Adjoining Grammar (FB-LTAG) formalism. The XTAG system integrates a morphological analyzer, an N-best part-of-speech tagger, an Early-style parser and an X-window interface, along with a wide-coverage grammar for English developed using the

Dania Egedi, Martha Palmer

Lexical selection in Machine Translation consists of several related components. Two that have received a lot of attention are lexical mapping from an underlying concept or lexical item, and choosing the correct subcategorization frame based on argument structure. Because most MT applications are small or relatively domain specific, a third component of lexi

Beth Ann Hockey, Dania Egedi

Previous work on English determiners has primarily concentrated on their semantics or scoping properties rather than their complex ordering behavior. The little work that has been done on determiner ordering generally splits determiners into three subcategories. However, this small number of categories does not capture the finer distinctions necessary to cor

Eric R. Bittner, John C. Light

The role of shape resonances and many-body effects on universal quantum sticking of ultra cold atoms onto solid surfaces is examined analytically and computationally using an exactly solvable representation of the Dyson equation. We derive the self-energy renormalization of the the transition amplitude between an ultra cold scattering atom and the bound stat

Ivan Gjaja

The problem considered is the computation of an infinite product (composition) of Lie transformations generated by homogeneous polynomials of increasing order from a given convergent power series. Bounds are computed for the infinitesimal form of Lie transformations. The results obtained do not guarantee convergence of the product. Instead, the optimum trunc

A. Cavaliere, N. Menci

We present a new approach to the statistics of the cosmic density field and to the mass distribution of high-contrast structures, based on the formalism of Cayley trees. Our approach includes in one random process both fluctuations and interactions of the density perturbations. We connect tree-related quantities, like the partition function or its generating

Hans Kjeldsen, Timothy R. Bedding, Michael Viskum, Soeren Frandsen

We have observed evidence for $p$-mode oscillations in the G0 IV star etaBoo (V = 2.68). This represents the first clear evidence of solar-like oscillations in a star other than the Sun. We used a new technique which measures fluctuations in the temperature of the star via their effect on the equivalent widths of the Balmer lines. The observations were obtai

Wolfgang J. Duschl, Harald Lesch

We discuss the radio spectrum of Sgr A* \index{Sgr A*, radio spectrum} in the frequency range between $\approx 1\,{\rm GHz}$ and $\approx 1\,000\,{\rm GHz}$, show that it can be explained by optically thin synchrotron radiation \index{Sgr A*, synchrotron radiation, optically thin} of relativistic electrons, and point toward a possible correlation between the

István Szapudi, Gavin Dalton, George Efstathiou, Alexander Szalay

We apply a new statistics, the factorial moment correlators, to density maps obtained from the APM survey. The resulting correlators are all proportional to the two point correlation function, substantially amplified, with an amplification nearly exponential with the total rank of the correlators. This confirms the validity of the hierarchical clustering ass

Yasusada Nambu, Atsushi Taruya

Using the long wave perturbation scheme(gradient expansion), the effect of inhomogeneity on the inflationary phase is investigated. We solved the perturbation equation of which source term comes from inhomogeneity of a scalar field and a seed metric. The result indicates that sub-horizon scale inhomogeneity strongly affects the onset of inflation.

Jane C. Charlton, Pablo Laguna

The globular clusters that we observe in galaxies may be only a fraction of the initial population. Among the evolutionary influences on the population is the destruction of globular clusters by tidal forces as the cluster moves through the field of influence of a disk, a bulge, and/or a putative nuclear component (black hole). We have conducted a series of

J. W. Moffat

A new version of nonsymmetric gravitational theory is presented. The field equations are expanded about the Minkowski metric, giving in lowest order the linear Einstein field equations and massive Proca field equations for the antisymmetric field $g_{[μν]}$. An expansion about an arbitrary Einstein background metric yields massive Proca field equations with

Rene Lafrance, Robert C. Myers

Limits for the applicability of the equivalence principle are considered in the context of low-energy effective field theories. In particular, we find a class of higher-derivative interactions for the gravitational and electromagnetic fields which produce dispersive photon propagation. The latter is illustrated by calculating the energy-dependent contributio

Shahrzad Mahootian, Beatrice Santorini

In codeswitching contexts, the language of a syntactic head determines the distribution of its complements. Mahootian 1993 derives this generalization by representing heads as the anchors of elementary trees in a lexicalized TAG. However, not all codeswitching sequences are amenable to a head-complement analysis. For instance, adnominal adjectives can occupy

Anirban Kundu, Probir Roy

This paper is withdrawn. A revised and expanded version of this work is available as hep-ph/9603323.

Simon Hands

The Thirring model, that is, a relativistic field theory of fermions with a contact interaction between vector currents, is studied for dimensionalities 2<d<4 using the 1/N_f expansion, where N_f is the number of fermion species. The model is found to have no ultraviolet divergences at leading order provided a regularization respecting current conservation i

A. Galli

We present a lattice analysis of a confining Yang-Mills theory without Goldstone boson. We have analytically investigated the model by a strong coupling expansion and by an intensive lattice Monte Carlo simulation using standard lattice QCD methods. We show that this theory is an interesting candidate for describing weak bosons as composite particles.

Izawa K. -I

An argument is given which exhibits color confinement in nonabelian gauge theory.

M. Bucher, A. S. Goldhaber, N. Turok

We present a natural scenario for obtaining an open universe ($Ω_0<1$) through inflation. In this scenario, there are two epochs of inflationary expansion---an epoch of `old inflation,&#39; during which the inflaton field is stuck in a false vacuum, followed by an epoch of `new inflation,&#39; during which the inflaton field slowly rolls toward its true mini

R. Stern, M. Mali, J. Roos, D. Brinkmann

We report measurements of the Gaussian contribution, T_{2G}, to the plane ^{63}Cu nuclear spin--spin relaxation time in the YBa_2Cu_3O_7 and YBa_2Cu_4O_8 blocks of normal and superconducting Y_2Ba_4Cu_7O_{15}. The data confirm our previous results that adjacent CuO_2 planes have different doping levels and that these planes are strongly coupled. -- The stati

Larus Thorlacius

Black hole formation and evaporation is studied in the semiclassical approximation in simple 1+1-dimensional models, with emphasis on issues related to Hawking&#39;s information paradox. Exact semiclassical solutions are described and questions of boundary conditions and vacuum stability are discussed. The validity of the semiclassical approximation has been

Vipul Periwal

The free energy is shown to decrease along Wilson renormalization group trajectories, in a dimension-independent fashion, for $d>2.$ The argument assumes the monotonicity of the cutoff function, and positivity of a spectral representation of the two point function. The argument is valid to all orders in perturbation theory.

Denis Bernard

In the first part, we introduce the notion of fractional statistics in the sense of Haldane. We illustrate it on simple models related to anyon physics and to integrable models solvable by the Bethe ansatz. In the second part, we describe the properties of the long-range interacting spin chains. We describe its infinite dimensional symmetry, and we explain h

A. Pasquinucci, K. Roland

We present the technical tools needed to compute any one-loop amplitude involving external spacetime fermions in a four-dimensional heterotic string model a` la Kawai-Lewellen-Tye. As an example, we compute the one-loop three-point amplitude with one &#34;photon&#34; and two external massive fermions (&#34;electrons&#34;). As a check of our computation, we v

K. Hamada

The recursion relations of 2D quantum gravity coupled to the Ising model discussed by the author previously are reexamined. We study the case in which the matter sector satisfies the fusion rules and only the primary operators inside the Kac table contribute. The theory involves unregularized divergences in some of correlators. We obtain the recursion relati

T. Jonsson, J. F. Wheater

We construct a random surface model with a string susceptibility exponent one quarter by taking an Ising model on a random surface and introducing an additional degree of freedom which amounts to allowing certain outgrowths on the surfaces. Fine tuning the Ising temperature and the weight factor for outgrowths we find a triple point where the susceptibility

I. Antoniadis, S. D. Odintsov

We study the effective theory of the conformal factor near its infrared stable fixed point.The renormalization group equations for the effective coupling constants are found and their solutions near the critical point are obtained, providing the logarithmic corrections to scaling relations.Some cosmological applications of the running of coupling constants a

T. S. Hakobyan, A. G. Sedrakyan

We use the functional representation of Heisenberg-Weyl group and obtain equation for the spectrum of the model, which is more complicated than Bethes ones, but can be written explicitly through theta functions.

S. O. Warnaar, P. A. Pearce

We conjecture polynomial identities which imply Rogers--Ramanujan type identities for branching functions associated with the cosets $({\cal G}^{(1)})_{\ell-1}\otimes ({\cal G}^{(1)})_{1} / ({\cal G}^{(1)})_{\ell}$, with ${\cal G}$=A$_{n-1}$ \mbox{$(\ell\geq 2)$}, D$_{n-1}$ $(\ell\geq 2)$, E$_{6,7,8}$ $(\ell=2)$. In support of our conjectures we establish th

John C. Collins, Davison E. Soper

The CTEQ and MRS parton distributions involve a substantial number (~30) of parameters that are fit to a large number (~900) of data. Typically, these groups produce fits that represent a good fit to the data, but there is no substantial attempt to determine the errors associated with the fits. Determination of errors would involve consideration of the exper

Isard Dunietz, Jonathan L. Rosner

The correlations between a $B$ meson and a pion produced nearby in phase space should respect isospin reflection symmetry $I_3 \to -I_3$. Thus, one generally expects similar $π^+ B^0$ and $π^- B^+$ correlations (non-exotic channels), and similar $π^- B^0$ and $π^+ B^+$ correlations (exotic channels). Exceptions include (a) fragmentation processes involving e

I. Sarcevic, H. -Th. Elze

We present an effective field theory of multiparticle correlations based on analogy with Ginzburg-Landau theory of superconductivity. With the assumption that the field represents particle density fluctuations, and in the case of gaussian-type effective action we find that there are no higer-order correlations, in agreement with the recent observations in hi

G. P. Korchemsky, G. Sterman

We show that the resummation of large perturbative corrections in QCD leads to ambiguities in high energy cross sections that are suppressed by powers of large momentum scales. These ambiguities are caused by infrared renormalons, which are a general feature of resummed hard-scattering functions in perturbative QCD, even though these functions are infrared s

N. Di Bartolomeo, F. Feruglio, R. Gatto, G. Nardulli

The hyperfine splittings $Δ_D=(m_{D^*_s}-m_{D_s})-(m_{D^{*+}}-m_{D^+})$ and $Δ_B=(m_{B^*_s}-m_{B_s})-(m_{B^{*0}}-m_{B^0})$ are analyzed in the framework of an effective lagrangian possessing chiral, heavy flavour and spin symmetries, explicitly broken by a complete set of first order terms. Among these terms, those responsible for the difference between the

A. V. Gladyshev, D. I. Kazakov

The one-loop radiative corrections to the Higgs boson potential in the MSSM, originating from the top quark and squark loops, are summed in the leading log approximation using the renormalization group. The RG improved effective potential is minimized and the corrections to the CP-odd and CP-even Higgs boson masses are calculated. The resulting masses exhibi

Rathin Adhikari, Biswarup Mukhopadhyaya

If a light gaugino sector exists, then the lightest supersymmetric particle (LSP) has a chance of being pair-produced in rare B-decays. As a consequence of neutral flavour violation in most supersymmetric models, such decays can occur at the tree-level and reinforce the channels $B \longrightarrow K(K^{*}) + invisible$. We discuss how a study of such decay s

A. Galli

We consider a confining Yang-Mills theory without Goldstone Bosons which could describe the bosonic sector of the weak interactions. This model can be gauge invariantly regularized on a lattice. A strong coupling analysis of the low lying bound state spectrum indicates that the vector isotriplet bound state (the right quantum number to represent the W-boson)

A. Galli

We present a lattice Monte Carlo simulation for the evaluation of the spectrum of a confining Yang-Mills theory without Goldstone boson. We show that this theory is a very good candidate for describing composite weak bosons. In order to perform the spectrum analysis we have used standard lattice QCD Monte Carlo methods. We have also developed an efficient me

John C. Baez

Given a real-analytic manifold M, a compact connected Lie group G and a principal G-bundle P -> M, there is a canonical `generalized measure&#39; on the space A/G of smooth connections on P modulo gauge transformations. This allows one to define a Hilbert space L^2(A/G). Here we construct a set of vectors spanning L^2(A/G). These vectors are described in ter

Carlo Rovelli, Lee Smolin

We study the operator that corresponds to the measurement of volume, in non-perturbative quantum gravity, and we compute its spectrum. The operator is constructed in the loop representation, via a regularization procedure; it is finite, background independent, and diffeomorphism-invariant, and therefore well defined on the space of diffeomorphism invariant s

Alain Joye

The adiabatic approximation in quantum mechanics is considered in the case where the self-adjoint hamiltonian $H_0(t)$, satisfying the usual spectral gap assumption in this context, is perturbed by a term of the form $εH_1(t)$. Here $ε\to 0$ is the adiabaticity parameter and $H_1(t)$ is a self-adjoint operator defined on a smaller domain than the domain of $

James C. Osborn, Alan T. Dorsey

The dynamics of the normal/superconducting interface in type-I superconductors has recently been derived from the time-dependent Ginzburg-Landau theory of superconductivity. In a suitable limit these equations are mapped onto a ``free-boundary&#39;&#39; problem, in which the interfacial dynamics are determined by the diffusion of magnetic flux in the normal

Chung-Yu Mou, Rachel Wortis, Alan T. Dorsey, David A. Huse

Multiterminal transport measurements on YBCO crystals in the vortex liquid regime have shown nonlocal conductivity on length scales up to 50 microns. Motivated by these results we explore the wavevector ({\bf k}) dependence of the dc conductivity tensor, $σ_{μν} ({\bf k})$, in the Meissner, vortex lattice, and disordered phases of a type-II superconductor. O

M. Mueller, N. B. Wilding

A semi-grand-canonical Monte Carlo algorithm is employed in conjunction with the bond fluctuation model to investigate the critical properties of an asymmetric binary (AB) polymer mixture. By applying the equal peak-weight criterion to the concentration distribution, the coexistence curve separating the A-rich and B-rich phases is identified as a function of

R. F. Bishop, N. J. Davidson, Y. Xian

A review is given of our recent application of a systematic microscopic formulation of quantum many-body theory, namely the coupled-cluster method (CCM), to Hamiltonian $U(1)$ lattice gauge models in the pure gauge sector. It is emphasized that our CCM results represent a natural extension or resummation of the results from the strong-coupling perturbation t

Enrique Diez, Francisco Dominguez-Adame, Angel Sanchez

We study resonant tunneling in B-$δ$-doped diodes grown by Si-molecular beam epitaxy. A Thomas-Fermi approach is used to obtain the conduction-band modulation. Using a scalar Hamiltonian within the effective-mass approximation we demonstrate that the occurrence of negative differential resistance (NDR) only involves conduction-band states, whereas interband

Y. Ohta, R. Eder

A detailed exact-diagonalization study is made for the doping dependence of the single-particle spectral function $A({\bf k},ω)$ and momentum distribution function $n({\bf k})$ of the two-dimensional $t$$-$$J$ model as a representative model for doped Mott insulators. The results for $A({\bf k},ω)$ show unambiguously that the rigid-band behavior is realized

Michael Marder, Steve Gross

This paper demonstrates that rapid fracture of ideal brittle lattices naturally involves phenomena long seen in experiment, but which have been hard to understand from a continuum point of view. These idealized models do not mimic realistic microstructure, but can be solved exactly and understood completely. First it is shown that constant velocity crack sol

D. R. Garnett, E. D. Skillman, R. J. Dufour, M. Peimbert

We present FOS observations of O III] 1666 A and C III] 1909 A emission in H II regions in dwarf irregular galaxies to measure C/O abundance ratios in those galaxies. We observe a continuous increase in C/O with increasing O/H over the range -4.7 < log(O/H) < -3.6. One interpretation is that the most metal-poor galaxies are the youngest and dominated by the

Ruth Durrer

We discuss gravitational effects of global scalar fields and, especially, of global topological defects. We first give an introduction to the dynamics of global fields and the formation of defects. Next we investigate the induced gravitational fields, first in a flat background and then in the expanding universe. In flat space, we explicitly calculate the gr

Don N. Page

It is suggested that probabilities need not apply at all to matter in the physical world, which may be entirely described by the amplitudes given by the quantum mechanical state. Instead, probabilities may apply only to conscious perceptions in the mental world. Such perceptions may not form unique sequences that one could call individual minds.

Kenneth G. Wilson, Martina Brisudova

This paper consists of an overview of the discussions on chiral symmetry breaking followed by a transcript of the discussions themselves. (Based on discussions at ``Theory of Hadrons and Light-Front QCD,&#39;&#39; Polana Zgorzelisko, Poland, August 1994.)

A. P. Martynenko, V. A. Saleev

The decay widths of S-wave quarkonia ($\etc,\etb\to \gg{~~and~~} \J,\U\to\ee$) are calculated on the basis of a quasipotential approach. The nontrivial dependence on relative quark motion of decay amplitude is taken into consideration via quarkonium wave function. It is shown that relativistic corrections may be large (10-50 %) and comparable with QCD correc

C. Klimcik, P. Severa

A simple geometric description of T-duality is given by identifying the cotangent bundles of the original and the dual manifold. Strings propagate naturally in the cotangent bundle and the original and the dual string phase spaces are obtained by different projections. Buscher&#39;s transformation follows readily and it is literally projective. As an applica

H. Castella, X. Zotos, P. Prelovsek

We analyse the finite temperature charge stiffness D(T>0), by a generalization of Kohn&#39;s method, for the problem of a particle interacting with a fermionic bath in one dimension. We present analytical evidence, using the Bethe ansatz method, that D(T>0) is finite in the integrable case where the mass of the particle equals the mass of the fermions and nu

Peter Johansson

The cyclotron resonance absorption spectrum in a Wigner crystal is calculated. Effects of spin-splitting are modelled by substitutional disorder, and calculated in the coherent potential approximation. Due to the increasing strength of the dipole-dipole interaction, the results show a crossover from a double-peak spectrum at small filling factors to a single

Masako Bando, Joe Sato, Tomohiko Takahashi

We study the possibility of an intermediate scale existing in supersymmetric SO(10) grand unified theories: The intermediate scale is demanded to be around 10^{12} GeV so that neutrinos can obtain masses suitable for explaining the experimental data on the deficit of solar neutrino with Mikheev-Smirnov-Wolfenstein solution and the existence of hot dark matte

Shahn Majid

We present a systematic introduction to the geometry of linear braided spaces. These are versions of $\R^n$ in which the coordinates $x_i$ have braid-statistics described by an R-matrix. From this starting point we survey the author&#39;s braided-approach to $q$-deformation: braided differentiation, exponentials, Gaussians, integration and forms, i.e. the ba

Steven Nerney, Edward J. Schmahl, Z. E. Musielak

The well-known analytical solution of Burgers&#39; equation is extended to curvilinear coordinate systems in three-dimensions by a method which is much simpler and more suitable to practical applications than that previously used. The results obtained are applied to incompressible flow with cylindrical symmetry, and also to the decay of an initially linearly

S. Ying, E. M. Henley

We examine time reversal invariance in the beta-decays of 8B(2+) and 8Li(2+) to 8Be(2+) in detail, with particular attention to final state interactions of the two alpha particles from the decay of 8Be, and of the electron (positron) with the daughter nucleus. A R-matrix formulation is used, with the initial state described by a shell model. The R-matrix par

Donald E. Knuth

An $\{r,s\}$-leaper is a generalized knight that can jump from $(x,y)$ to $(x\pm r,y\pm s)$ or $(x\pm s,y\pm r)$ on a rectangular grid. The graph of an $\{r,s\}$-leaper on an $m\times n$ board is the set of $mn$~vertices $(x,y)$ for $0\leq x<m$ and $0\leq y<n$, with an edge between vertices that are one $\{r,s\}$-leaper move apart. We call $x$ the {\it rank}

Greg Kuperberg

A method of Proctor [European J. Combin. 5 (1984), no. 4, 331-350] realizes the set of arbitrary plane partitions in a box and the set of symmetric plane partitions as bases of linear representations of Lie groups. We extend this method by realizing transposition and complementation of plane partitions as natural linear transformations of the representations

Arnold W. Miller

A sequence of functions f_n: X -> R from a Baire space X to the reals is said to converge in category iff every subsequence has a subsequence which converges on all but a meager set. We show that if there exists a Souslin Tree then there exists a nonatomic Baire space X such that every sequence which converge in category converges everywhere on a comeager se

Kenneth G. Wilson, David G. Robertson

A general strategy is described for deriving a constituent approximation to QCD, inspired by the constituent quark model and based on light-front quantization. Some technical aspects of the approach are discussed, including a mechanism for obtaining a confining potential and ways in which spontaneous chiral symmetry breaking can be manifested. (Based on a ta

Gaetano Fiore

We propose a nonstandard approach to solving the apparent incompatibility between the coalgebra structure of some inhomogeneous quantum groups and their natural complex conjugation. In this work we sketch the general idea and develop the method in detail on a toy-model; the latter is a q-deformation of the Hopf algebra of 1-dim translations + dilatations. We

L. A. Dickey

A constrained KP hierarchy is discussed that was recently suggested by Aratyn et al. and by Bonora et al. This hierarchy is a restriction of the KP to a submanifold of operators which can be represented as a ratio of two purely differential operators of prescribed orders. Explicit formulas for action of vector fields on these two differential operators are w

Giovanni Felder, Christian Wieczerkowski

We give an explicit description of the vector bundle of WZW conformal blocks on elliptic curves with marked points as subbundle of a vector bundle of Weyl group invariant vector valued theta functions on a Cartan subalgebra. We give a partly conjectural characterization of this subbundle in terms of certain vanishing conditions on affine hyperplanes. In some

V. Radovanović, Dj. Šijački

It is shown that the $SU(2)$ Yang-Mills theory in $3$-dimensional Riemann-Cartan space-time can be completely reformulated as a gravity-like theory in terms of gauge invariant variables. The resulting Yang-Mills induced equations are found, and it is demonstrated that they can be derived from a torsion-square type of action.

O. Lechtenfeld, S. Samuel

Four-dimensional twisted group lattices are used as models for space-time structure. Compared to other attempts at space-time deformation, they have two main advantages: They have a physical interpretation and there is no difficulty in putting field theories on these structures. We present and discuss ordinary and gauge theories on twisted group lattices. We

A. Garrett Lisi

We investigate a class of localized, stationary, particular numerical solutions to the Maxwell-Dirac system of classical nonlinear field equations. The solutions are discrete energy eigenstates bound predominantly by the self-produced electric field.

Paul A. Griffin

A calculational framework for determining masses of low lying hadrons using light front quantization is discussed. The method is based upon four theoretical tools: discrete light cone quantization, which has been very successful in 1+1 dimensional models, a projector Monte Carlo method to extract low lying state data with 2 additional transverse dimensions,

Hidenori Sonoda

Given a renormalization scheme of QCD, one can define a mass scale $Λ_{\rm QCD}$ in terms of the beta function. Under a change of the renormalization scheme, however, $Λ_{\rm QCD}$ changes by a multiplicative constant. We introduce a scheme independent $Λ_{\rm QCD}$ using a connection on the space of the coupling constant.

B. Holdom

The color-octet isosinglet &#34;rho&#34; of a new strong-interaction sector is readily produced in ppbar collisions. Its odd-parity decay to an &#34;eta&#34; and a gluon may exceed its decay rate to dijets. At center of mass energies sufficiently greater than the colored &#34;rho&#34; mass, the odd-parity production of (&#34;omega&#34; + colored &#34;eta&#34

Richard F. Lebed

We compute and tabulate the Clesbsch--Gordan coefficients of the $SU(6) \supset SU(3) \times SU(2)$ product ${\overline{\bf 56}} \otimes {\bf 56}$, which are relevant to the nonrelativistic spin-flavor symmetry of the lightest baryons. Under the assumption that the largest representation in this product, the ${\bf 2695}$, gives rise to operators in a chiral

Jens Erler, Paul Langacker

We discuss the consequences of recent experimental results from CDF, SLC, LEP and elsewhere for the Standard Model and for new physics. A global fit to all indirect precision data yields $m_t = 175 \pm 11^{+17}_{-19}$~GeV, $\sin^2θ_{MS} = 0.2317(3)(2)$, and $α_s = 0.127(5)(2)$, where the central values are for $M_H = 300$ GeV and the second uncertainties are

S. P. de Alwis, D. A. MacIntire

Based on the analysis of two dimensional dilaton gravity we argue that the semiclassical equations of black hole formation and evaporation should not be interpreted in terms of expectation values of operators in the exact quantum theory, but rather as WKB trajectories. Thus at the semiclassical level it does not seem possible to formulate a notion of {\it qu

Dragoljub Markovic, Eric Poisson

For a certain region of the parameter space $\{M,e,Λ\}$, the Cauchy horizon of a (charged) black hole residing in de Sitter space is classically stable to gravitational perturbations. This implies that, when left to its own devices, classical theory is unable to retain full predictive power: the evolution of physical fields beyond the Cauchy horizon is not u

Valeri Frolov, Erik A. Martinez

We present the Hamiltonian, quasilocal energy, and angular momentum for a spacetime region spatially bounded by two timelike surfaces. The results are applied to the particular case of a spacetime representing an eternal black hole. It is shown that in the case when the boundaries are located in two different wedges of the Kruskal diagram, the Hamiltonian is

R. T. Scalettar, G. G. Batrouni, A. P. Kampf, G. T. Zimanyi

The Bose-Hubbard model exhibits a rich phase diagram consisting both of insulating regimes where diagonal long range (solid) order dominates as well as conducting regimes where off diagonal long range order (superfluidity) is present. In this paper we describe the results of Quantum Monte Carlo calculations of the phase diagram, both for the hard and soft co

Wei Chen, Y. Jack Ng

Do anyons, dynamically realized by the field theoretic Chern-Simons construction, obey fractional exclusion statistics? We find that they do if the statistical interaction between anyons and anti-anyons is taken into account. For this anyon model, we show perturbatively that the exchange statistical parameter of anyons is equal to the exclusion statistical p

Raymond E. Goldstein, David P. Jackson, Alan T. Dorsey

A theory is developed of the intricately fingered patterns of flux domains observed in the intermediate state of thin type-I superconductors. The patterns are shown to arise from the competition between the long-range Biot-Savart interactions of the Meissner currents encircling each region and the superconducting-normal surface energy. The energy of a set of

Chinorat Kobdaj, Steven Thomas

We study charge screening in a system of two dimensional nonabelian vortices, at finite temperature. Such vortices are generated after an \( SO(3) \) global symmetry group is spontaneously broken to a discrete subgroup \( \IQ_8 \), where the latter is isomorphic to the nonabelian group of quaternions. Poisson-Boltzmann like equations are derived for the vari

Hideki ONO, Hiroshi KURATSUJI

The purpose of this paper is to present a quantum statistical theory of 2-dimensional vortex gas based on the generalized Hamiltonian dynamics recently developed. The quantized spectrum is evaluated for a pair of vortex on the basis of the semiclassical quantization rule. This is used to evaluate the partition function for a dilute vortex gas. A remarkable c

A. J. Guttmann, I. G. Enting, latex

We have extended the high-temperature susceptibility series of the three-dimensional spin-1\2 Ising model to v**26. Analysis of the new series gives alpha = 0.101 +- 0.004.

H. F. Chau, L. Mak, P. K. Kwok

A punctuated equilibrium model of biological evolution with relative fitness between different species being the fundamental driving force of evolution is introduced. Mutation is modeled as a fitness updating cellular automaton process where the change in fitness after mutation follows a Gaussian distribution with mean $x>0$ and standard deviation $σ$. Scali

Hiyan Alshawi, David Carter, Richard Crouch, Steve Pulman

This report describes the research, design and implementation work carried out in building the CLARE system at SRI International, Cambridge, England. CLARE was designed as a natural language processing system with facilities for reasoning and understanding in context and for generating cooperative responses. The project involved both further development of S

Robert M. Losee, Stephanie W. Haas

The use of terms from natural and social scientific titles and abstracts is studied from the perspective of sublanguages and their specialized dictionaries. Different notions of sublanguage distinctiveness are explored. Objective methods for separating hard and soft sciences are suggested based on measures of sublanguage use, dictionary characteristics, and

Stephen E. Zepf

I discuss how spectroscopy of extragalactic globular clusters provides a powerful probe of the formation history and mass distribution of galaxies. One critical area is spectroscopy of objects which have been identified as candidate young globular clusters through HST imaging of galaxy mergers. I discuss how such data can constrain models of globular cluster