November 1994 arXiv papers — page 10

J. Bijnens, G. Ecker, J. Gasser

An introduction to Chiral Perturbation Theory is given including a discussion of power counting, the Wess-Zumino term, the values of the coupling constants and the inclusion of the effects of other resonances.

C. R. Allton, M. Crisafulli, V. Lubicz, G. Martinelli

We present the results of a high statistics lattice calculation of hadronic form factors relevant for $D-$ and $B-$meson semi-leptonic decays into light pseudoscalar and vector mesons. The results have been obtained by averaging over 170 gauge field configurations, generated in the quenched approximation, at $β=6.0$, on a $18^3 \times 64$ lattice, using the

G. Martinelli, C. Pittori, C. T. Sachrajda, M. Testa

We propose a non-perturbative method for computing the renormalization constants of generic composite operators. This method is intended to reduce some systematic errors, which are present when one tries to obtain physical predictions from the matrix elements of lattice operators. We also present the results of a calculation of the renormalization constants

J. Ambjorn, J. Jurkiewicz

It is known that there are four-manifolds which are not algorithmically recognizable. This implies that there exist triangulations of these manifolds which are separated by large barriers from the point of view of the computer algorithm. We have not observed these barriers for triangulations of $S^4$.

A. Galli

The phase structure of lattice QCD with two flavors and Wilson fermions is studied analytically. At $β=0$ we obtain rigorous lower and upper bounds for the critical hopping parameter $k_c(0)$ from a convergent hopping parameter expansion to infinite order. The result supports the value $k_c(0)=\frac{1}{4}$ observed in Monte Carlo simulations.

Shun'ya Mizoguchi

We study the Geroch group in the framework of the Ashtekar formulation. In the case of the one-Killing-vector reduction, it turns out that the third column of the Ashtekar connection is essentially the gradient of the Ernst potential, which implies that the both quantities are based on the ``same'' complexification. In the two-Killing-vector reductio

J. Fernando Barbero

I show in this letter that it is possible to solve some of the constraints of the $SO(3)$-ADM formalism for general relativity by using an approach similar to the one introduced by Capovilla, Dell and Jacobson to solve the vector and scalar constraints in the Ashtekar variables framework. I discuss the advantages of using the ADM formalism and compare the re

J. L. Rosales

A solution for the problem of understanding observed rotation curves in galaxies without the introduction of dark matter halos is presented. This solution has been obtained upon considering the distribution of masses in the expanding universe, then, having a cosmological character. A formal limiting radius for galaxies depending on cosmological parameters is

C. G. Torre

Existing mathematical results are applied to the problem of classifying closed $p$-forms which are locally constructed from Lorentzian metrics on an $n$-dimensional orientable manifold $M$ ($0<p<n$). We show that the only closed, non-exact forms are generated by representatives of cohomology classes of $M$ and $(n-1)$-forms representing $n$-dimensional (with

Guofang Wei

We derive a uniform bound for the total betti number of a closed manifold in terms of a Ricci curvature lower bound, a conjugate radius lower bound and a diameter upper bound. The result is based on an angle version of Toponogov comparison estimate for small triangles in a complete manifold with a Ricci curvature lower bound. We also give a uniform estimate

Alexander Reznikov

We study the set of volumes of constant scalar curvature one metrics on an atoroidal three-manifold.The infinum of this set is believed to be attained at a hyperbolic metric. We prove that the supremum of this set is always infinity. The technique is: minimal surfaces, Thurston norm in homology and new conformal invariants.

Michael C. Martin, J. Fabian, J. Godard, P. Bernier

The infrared (IR) spectrum of solid C60 exhibits many weak vibrational modes. Symmetry breaking due to 13C isotopes provides a possible route for optically activating IR-silent vibrational modes. Experimental spectra and a semi-empirical theory on natural abundance and 13C-enriched single crystals of C60 are presented. By comparing the experimental results w

Michael C. Martin, Daniel Koller, A. Rosenberg, C. Kendziora

The infrared- and Raman-active vibrational modes of C60 were measured in the various structural states of Rb1C60. According to earlier studies, Rb1C60 has an $fcc$ structure at temperatures above ~100C, a linear chain polymer orthorhombic structure when slowly cooled, and an as yet undetermined structure when very rapidly cooled (&#34;quenched&#34;). We show

D. M. Christodoulou, I. Shlosman, J. E. Tohline

We analyze previous results on the stability of uniformly and differentially rotating, self-gravitating, gaseous and stellar, axisymmetric systems to derive a new stability criterion for the appearance of toroidal, m=2 Intermediate (I) and bar modes. In the process, we demonstrate that the bar modes in stellar systems and the m=2 I-modes in gaseous systems h

Stephen E. Zepf, Keith M. Ashman, Doug Geisler

We present a study of the colors of globular clusters associated with the elliptical galaxy NGC 3923. Our final sample consists of Washington system C and T_1 photometry for 143 globular cluster candidates with an expected contamination of no more than 10%. We find that the color distribution of the NGC 3923 globular cluster system (GCS) is broad and appears

Nick Kaiser, Gordon Squires, Greg Fahlman, David Woods

Measurement of the gravitational distortion of images of distant galaxies is rapidly becoming established as a powerful probe of the dark mass distribution in clusters of galaxies. With the advent of large mosaics of CCD&#39;s these methods should provide a composite total mass profile for galaxy haloes and also measure the power spectrum of mass fluctuation

H. Andernach, R. J. Hanisch, F. Murtagh

The amount of data produced by large observational facilities and space missions has led to the archiving and on-line accessibility of much of this data, available to the entire astronomical community. This allows a much wider multi-frequency approach to astronomical research than previously possible. Here we provide an overview of these services, and give a

H. Andernach

From the literature of 1987 to 1993 a representative sample was prepared of 500 papers with tabular information for >~50 supposedly extragalactic objects each. Regardless of their scientific value, but corrected for redundancy, these papers contain 842,000 entries. For the 374 papers with >100 entries each, the CDS FTP-archive of catalogues contains tables f

H. Andernach

Current extragalactic databases are reviewed, including object-oriented databases, astronomical catalogues and compilations, as well as image archives and object catalogues from large-scale surveys. One challenge of the future will be to maintain the accessibility of all published information on individual objects; the other will be the cross-identification

A. Biviano, F. Durret, D. Gerbal, O. Le Fèvre

We have obtained new redshifts for 265 objects in the central 48~$\times$~25~arcmin$^2$ region of the Coma cluster. When supplemented with literature data, our redshift sample is 95~\% complete up to a magnitude b$_{26.5}$=18.0 (the magnitudes are taken from the photometric sample of Godwin et al. 1983). Using redshift-confirmed membership for 205 galaxies,

Brian Chaboyer, P. Demarque, D. B. Guenther, M. H. Pinsonneault

A new grid of theoretical isochrones based on the Yale stellar evolution code using the OPAL and Kurucz opacities has been constructed. The grid of isochrones spans a wide range of metallicities, helium abundances and masses. The construction of the isochrones is described and the isochrones are compared to galactic globular cluster observations. A solar cal

Albert A. Zijlstra

Mass loss dominates the stellar evolution on the Asymptotic Giant Branch. The phase of highest mass-loss occurs during the last 1--10\% of the AGB and includes the so-called Miras and OH/IR stars. In this review I will discuss the characteristics and evolution of especially Miras, and discuss how they are linked to the mass loss. There are indications that h

K. Chaltikian, L. Pryadko, S. C. Zhang

We show that the RMS fluctuation of the antisymmetric part of the Hall conductance of a planar mesoscopic metal in a random magnetic field with zero average is universal, of the order of $e^2/h$, independent of the amplitude of the random magnetic field and the diffusion coefficient even in the weak field limit. This quantity is exactly zero in the case of o

R. Parthasarathy, K. S. Viswanathan

The string world sheet, regarded as Riemann surface, in background $R^3$ and $R^4$ is described by the generalised Gauss map. When the Gauss map is harmonic or equivalently for surfaces of constant mean scalar curvature, we obtain an Abelian self-dual system, using $SO(3)$ and $SO(4)$ gauge fields constructed in our earlier studies. This compliments our earl

K. S. Viswanathan, R. Parthasarathy

In the description of the extrinsic geometry of the string world sheet regarded as a conformal immersion of a 2-d surface in $R^3$, it was previously shown that, restricting to surfaces with $h\surd{g}\ =\ 1$, where $h$ is the mean scalar curvature and $g$ is the determinant of the induced metric on the surface, leads to Virasaro symmetry. An explicit form o

M. Faber, H. Markum, S. Olejnik, W. Sakuler

Topological properties of the vacuum were investigated in finite-temperature lattice QCD without and with dynamical quarks using a local operator of topological charge density and a variant of cooling. Below the deconfinement temperature evidence for flux tube formation was observed in the distribution of topological charge density around a static $Q\bar Q$

G. Sardanashvily

In Parts I and II of the work (gr-qc/9405013, 9407032), we have shown that gravity is {\it sui generis} a Higgs field corresponding to spontaneous symmetry breaking when the fermion matter admits only the Lorentz subgroup of world symmetries of the geometric arena. From the mathematical viewpoint, the Higgs nature of gravity issues from the fact that differe

Sang-Yoon Kim

We study the scaling behavior of $M$-furcation $(M\!=\!2, 3, 4,\dots)$ sequences of $M^n$-period $(n=1,2,\dots)$ orbits in two coupled one-dimensional (1D) maps. Using a renormalization method, how the scaling behavior depends on $M$ is particularly investigated in the zero-coupling case in which the two 1D maps become uncoupled. The zero-coupling fixed map

Sang-Yoon Kim

We study the critical behavior of period doublings in $N$ symmetrically coupled area-preserving maps for many-coupled cases with $N>3$. It is found that the critical scaling behaviors depend on the range of coupling interaction. In the extreme long-range case of global coupling, in which each area-preserving map is coupled to all the other area-preserving ma

Paul J. Mancinelli, Amos Yahil

Local nonlinear approximations to the growth of cosmic perturbations are developed, resulting in relations, at a given epoch, between the peculiar velocity and gravity fields and their gradients. Only the equation of motion is approximated, while mass conservation and the computation of the gravitational field are treated exactly. The second-order relation i

H. Liebl, Gary R. Goldstein

The diquark model is used to calculate the electromagnetic polarizabilities and charge radii of the nucleons for three different potentials. Making the scalar diquark lower in mass introduces a mixing angle $θ$ between the $\left| 56\right\rangle $ and $\left| 70\right\rangle $ states ,which allows an improvement in value of all 6 properties. Generalizing th

Paolo Aschieri, Leonardo Castellani

The quantum commutations $RTT=TTR$ and the orthogonal (symplectic) conditions for the inhomogeneous multiparametric $q$-groups of the $B_n,C_n,D_n$ type are found in terms of the $R$-matrix of $B_{n+1},C_{n+1},D_{n+1}$. A consistent Hopf structure on these inhomogeneous $q$-groups is constructed by means of a projection from $B_{n+1},C_{n+1},D_{n+1}$. Real f

B. Jurco, M. Schlieker

In this paper we construct explicitly natural (from the geometrical point of view) Fock space representations (contragradient Verma modules) of the quantized enveloping algebras. In order to do so, we start from the Gauss decomposition of the quantum group and introduce the differential operators on the corresponding $q$-deformed flag manifold (asuumed as a

V. Gurarie

When heavy nuclei collide, a quark-gluon plasma is formed. The plasma is subject to strong electric field due to the charge of the colliding nuclei. The electric field can influence the behavior of the quark-gluon plasma. In particular, we might observe an increased number of quarks moving in the direction of that field, as we do in the standard electron-ion

M. Beneke, V. M Braun

We propose to extend the Brodsky-Lepage-Mackenzie scale-fixing prescription by resumming exactly any number of one-loop vacuum polarization insertions into one-loop diagrams. In this way, one makes maximal use of the information contained in one-loop perturbative corrections combined with the one-loop running of the effective coupling. The scale ambiguity at

T. Morii, S. Tanaka, T. Yamanishi

The recent high precision SMC data on polarized $μp$ scatterings have again confirmed that very little of the proton spin is carried by quarks. To unravel the mystery of the proton spin structure, it is quite important to know the behavior of the polarized gluon distribution. By using the positivity condition of distribution functions together with the unpol

Toshiyuki Morii

Based on a simple model which is compatible with the idea of the static quark model and the parton model, the polarized structure functions of proton and deuteron, two-spin asymmetries of $π^0$ in polarized $pp$ reactions and inelastic $J/ψ$ productions in polarized lepton-proton collisions are analyzed. In particular, an important role of polarized gluon di

P. Singha Deo, A. M. Jayannavar

We have studied the quantum transmission properties of serial stub and loop structures. Throughout we have considered free electron networks and the scattering arises solely due to the geometric nature of the problem. The band formation in these geometric structures is analyzed and compared with the conventional periodic potential scatterers. Some essential

Kikuo Harigaya, Yukihiro Shimoi, Shuji Abe

Exciton effects on soliton and bipolaron lattice states are investigated using an electron-lattice Peierls model with long-range Coulomb interactions. The Hartree-Fock (HF) approximation and the single-excitation configuration- interaction (single-CI) method are used to obtain optical absorption spectra. We discuss the following properties: (1) The attractio

H. T. Nieh, Gang Su, Bao-Heng Zhao

There has been a proof by Sewell that the hypothesis of off-diagonal long-range order in the reduced density matrix $ρ_2$ implies the Meissner effect. We present in this note an elementary and straightforward proof that not only the Meissner effect but also the property of magnetic flux quantization follows from the hypothesis. It is explicitly shown that th

Geunbae Lee Jong-Hyeok Lee Kyunghee Kim

A new tightly coupled speech and natural language integration model is presented for a TDNN-based large vocabulary continuous speech recognition system. Unlike the popular n-best techniques developed for integrating mainly HMM-based speech and natural language systems in word level, which is obviously inadequate for the morphologically complex agglutinative

D. E. Harris, C. S. Grant, H. Andernach

The Einstein On-Line Service (EOLS) is a simple menu-driven system which provides an intuitive method of querying over one hundred database catalogs. In addition, the EOLS contains over 30 CDROMs of images from the Einstein X-ray Observatory which are available for downloading. The EOLS provides all of our databases to the NASA Astrophysics Data System (ADS)

Joel R. Primack, Jon Holtzman, Anatoly Klypin, David O. Caldwell Comments 8 pages

Cold + Hot Dark Matter (CHDM) $Ω=1$ cosmological models require a total neutrino mass $\sim 5$ eV. Because recent data support the $ν_μ\to ν_τ$ oscillation explanation of the cosmic ray $ν_μ$ deficit, which requires that $m(ν_μ) \approx m(ν_τ)$, this suggests that $m(ν_μ) \approx m(ν_τ) \approx 2.4$ eV. The linear calculations and N-body simulation reported

Robert J. Perry

Light-front field theory offers a scenario in which a constituent picture of hadrons may arise, but only if cutoffs that violate explicit covariance and gauge invariance are used. The perturbative renormalization group can be used to approximate the cutoff QCD hamiltonian, and even at lowest orders the resultant hamiltonian displays interesting phenomenologi

Orlando Panella, Yogendra N. Srivastava

Assuming the existence of a heavy Majorana neutral particle arising from a composite model scenario we discuss the constraints imposed by present experimental limits of half-life neutrinoless double beta decay $(0νββ) $ measurements on the coupling of the heavy composite neutrinos to the gauge bosons. For neutrino masses $M_N = 1 $ TeV we obtain a rather wea

P. C. West

It is shown that if the momenta belong to an integral lattice, then every physical state of string theory leads to a symmetry of the scattering amplitudes. We discuss the role of this symmetry when the momenta are those provided by the usual D.D.F construction and show that the string compactified on the torus associated with the self-dual Lorentzian lattice

Haret C. Rosu, Marco Reyes

We apply the supersymmetric procedure to one-step random walks in one dimension at the level of the usual master equation, extending a study initiated by H.R. Jauslin [Phys. Rev. A {\bf 41}, 3407 (1990)]. A discussion of the supersymmetric technique for this discrete case is presented by introducing a formal second-order discrete master derivative and its ``

Vincent Stoks, J. J. de Swart

As a follow-up on our earlier paper we calculate the $χ^{2}$ of various $N\!N$ potential models with respect to the $np$ scattering data. We find that only the most recent potential models give a reasonably good description of these data. Almost none of the potentials is truly an $N\!N$ potential in the sense that it gives a good description of both $pp$ and

H. S. Matis, S. Beedoe, M. Bougteb, J. Carroll

The DLS collaboration has recently completed a high statistics study of dilepton production at the Bevalac. In particular, we have measured dielectrons (e+e-) from p-p and p-d collisions to understand the basic dilepton production mechanisms in the energy range from 1.05 - 4.9 GeV. These data can be used to determine the basic processes which contribute to n

Carl M. Bender, Joshua Feinberg

The one-dimensional harmonic oscillator wave functions are solutions to a Sturm-Liouville problem posed on the whole real line. This problem generates the Hermite polynomials. However, no other set of orthogonal polynomials can be obtained from a Sturm-Liouville problem on the whole real line. In this paper we show how to characterize an arbitrary set of pol

L. A. Ferreira, D. I. Olive, M. V. Saveliev

In the present note we suggest an affinization of a theorem by Kostrikin et.al. about the decomposition of some complex simple Lie algebras ${\cal G}$ into the algebraic sum of pairwise orthogonal Cartan subalgebras. We point out that the untwisted affine Kac-Moody algebras of types $A_{p^m-1}$ ($p$ prime, $m\geq 1$), $B_r, \, C_{2^m}, D_r,\, G_2,\, E_7,\, E

A. G. Ushveridze

The systems of differential equations whose solutions coincide with Bethe ansatz solutions of generalized Gaudin models are constructed. These equations we call the {\it generalized spectral Riccati equations}, because the simplest equation of this class has a standard Riccatian form. The general form of these equations is $R_{n_i}[z_1(λ),\ldots, z_r(λ)] = c

J. Donin, D. Gurevich

Given a simple Lie algebra $\gggg$, we consider the orbits in $\gggg^*$ which are of R-matrix type, i.e., which possess a Poisson pencil generated by the Kirillov-Kostant-Souriau bracket and the so-called R-matrix bracket. We call an algebra quantizing the latter bracket a quantum orbit of R-matrix type. We describe some orbits of this type explicitly and we

Piotr Kosinski, Pawel Maslanka

The full duality between the $κ$-Poincaré algebra and $κ$-Poincaré group is proved.

G. S. Danilov

It is shown that the vacuum value of the $2d$ gravity stress tensor in the free field theory is singular in the fundamental region on the complex plane where the genus-$n>1$ Riemann surface are mapped. Because of the above singularity, one can not construct modular invariant multi-loop amplitudes. The discussed singularity is due to the singularity in the va

Raimund Varnhagen

Starting from Laughlin type wave functions with generalized periodic boundary conditions describing the degenerate groundstate of a quantum Hall system we explictly construct $r$ dimensional vector bundles. It turns out that the filling factor $ν$ is given by the topological quantity $c_1 \over r$ where $c_1$ is the first chern number of these vector bundles

C. P. Martin, F. Ruiz Ruiz

The renormalization algorithm based on regularization methods with two regulators is analyzed by means of explicit computations. We show in particular that regularization by higher covariant derivative terms can be complemented with dimensional regularization to obtain a consistent renormalized 4-dimensional Yang-Mills theory at the one-loop level. This show

Joseph Polchinski

The first part is an introduction to conformal field theory and string perturbation theory. The second part deals with the search for a deeper answer to the question posed in the title. Contents: 1. Conformal Field Theory 2. String Theory 3. Vacua and Dualities 4. String Field Theory or Not String Field Theory 5. Matrix Models

Ryuji KEMMOKU, Satoru SAITO, 13 pages, Latex

It is shown that the $W_{1+\infty}$ algebra is nothing but the simplest subalgebra of a $q$-discretized \vi\ algebra, in the language of the KP hierarchy explicitly.

R. C. Hwa

The normalized factorial moments $F_q$ are continued to noninteger values of the order $q$, satisfying the condition that the statistical fluctuations remain filtered out. That is, for Poisson distribution $F_q = 1$ for all $q$. The continuation procedure is designed with phenomenology and data analysis in mind. Examples are given to show how $F_q$ can be ob

Arild Skjold

We discuss how one may determine whether some Higgs particle is an eigenstate of $CP$ or not, and if so, how we may probe whether it is $CP$-odd or $CP$-even. The idea is applied to Higgs decay where correlations among momenta of the decay products may yield the desired information. These are correlations of decay planes defined by the momenta of pairs of pa

Jisuke Kubo, Myriam Mondragon, George Zoupanos

We discuss the basic idea of the Gauge-Yukawa Unification that is based on the principle of the reduction of couplings. This method of unification relies on the search of successful renormalization group invariant relations among couplings, which do not originate from symmetry principles. The predictive power of Grand Unified Theories can be increased by thi

Chi-Keung Chow

There exist heavy tetraquark states $QQ \bar q \bar q$ in the heavy quark limit. These states are stable with respect to strong interactions and hence must decay weakly. It is shown that the semileptonic decay depends on a single Isgur--Wise form factor, which can be expressed in term of the Isgur--Wise form factors which govern the semileptonic decays of th

V. D. Ivashchuk, V. N. Melnikov

The degenerate Lagrangian system describing a lot of cosmological models is considered. When certain restrictions on the parameters of the model are imposed, the dynamics of the model near the &#34;singularity&#34; is reduced to a billiard on the Lobachevsky space. The Wheeler-DeWitt equation in the asymptotical regime is solved and a third-quantized model i

Alan D. Rendall

It is shown that the initial singularities in spatially compact spacetimes with spherical, plane or hyperbolic symmetry admitting a compact constant mean curvature hypersurface are crushing singularities when the matter content of spacetime is described by the Vlasov equation (collisionless matter) or the wave equation (massless scalar field). In the spheric

H. Falomir, R. E. Gamboa Saraví, M. A. Muschietti, E. M. Santangelo

We study functional determinants for Dirac operators on manifolds with boundary and discuss the ellipticity of boundary problems by using the Calderón projector. We give, for local boundary conditions, an explicit formula relating these determinants to the corresponding Green functions. We finally apply this result to the case of a bidimensional disk under b

Claude LeBrun, Shin Nayatani, Takashi Nitta

We prove that the connected sums CP_2 # CP_2 and CP_2 # CP_2 # CP_2 admit self-dual metrics with positive Ricci curvature. Moreover, every self-dual metric of positive scalar curvature on CP_2 # CP_2 is conformal to a metric with positive Ricci curvature.

J. J. Deisz, D. W. Hess, J. W. Serene

We present a massively parallel algorithm for calculating the self-energy in self-consistent finite temperature perturbation theory for lattice models. The algorithm uses analytic functions with appropriate asymptotic high frequency behavior and fast Fourier transforms to accurately calculate the self-energy at low-frequency. Traditional methods that truncat

Mads Nielsen, Per Hedegaard

We have considered the conductivity properties of a two dimensional electron gas (2DEG) in two different kinds of inhomogeneous magnetic fields, i.e. a disordered distribution of magnetic flux vortices, and a periodic array of magnetic flux vortices. The work falls in two parts. In the first part we show how the phase shifts for an electron scattering on an

Per Hedegard, Anders Smith

A general framework for solving the Boltzmann equation for a 2-dimensional electron gas (2DEG) in random magnetic fields is presented, when the random fields are included in the driving force. The formalism is applied to some recent experiments, and a possible extension to composite fermions at $ν=1/2$ is discussed.

L. B. Ioffe, A. J. Millis

We compute the leading behavior of the uniform magnetic susceptibility, $χ$, of a Fermi liquid near an antiferromagnetic transition with dynamic exponent $z=2$. Our calculation clarifies the role of triangular ``anomaly&#39;&#39; graphs in the theory and justifies the effective action used in previous work \cite{Hertz}. We find that at the $z=2$ critical poi

Stephan Haas, Adriana Moreo, Elbio Dagotto

A consequence of strong antiferromagnetic correlations in models of high-Tc cuprates is the appearance in photoemission (PES) calculations of considerable more weight above the Fermi momentum ${\rm {\bf p}_F }$ than expected for non-interacting electrons. This effect, first discussed by Kampf and Schrieffer (Phys. Rev. {\bf B 41}, 6399 (1990)) under the name

Robert Frank

Current syntactic theory limits the range of grammatical variation so severely that the logical problem of grammar learning is trivial. Yet, children exhibit characteristic stages in syntactic development at least through their sixth year. Rather than positing maturational delays, I suggest that acquisition difficulties are the result of limitations in manip

Fernando Gomez, Richard Hull, Carlos Segami

A computational model for the acquisition of knowledge from encyclopedic texts is described. The model has been implemented in a program, called SNOWY, that reads unedited texts from {\em The World Book Encyclopedia}, and acquires new concepts and conceptual relations about topics dealing with the dietary habits of animals, their classifications and habitats

Christian Boitet, Mark Seligman

We present a new software architecture for NLP systems made of heterogeneous components, and demonstrate an architectural prototype we have built at ATR in the context of Speech Translation.

Alexander Matro, Jeffrey A. Cina

Calculations of time-resolved fluorescence anisotropy from a pair of chromophores coupled by an excitation transfer interaction are presented. For the purpose of investigating the effects of nuclear motion on the energy transfer and anisotropy, an illustrative model is developed that provides each chromophore with a single intramolecular vibrational mode. Ac

Timothy C. Germann, Dudley R. Herschbach, Bruce M. Boghosian

A recently developed linear algebraic method for the computation of perturbation expansion coefficients to large order is applied to the problem of a hydrogenic atom in a magnetic field. We take as the zeroth order approximation the $D \rightarrow \infty$ limit, where $D$ is the number of spatial dimensions. In this pseudoclassical limit, the wavefunction is

Ming Wen Sung, Ryoichi Kawai, John H. Weare

Packing transitions in the lowest energy structures of Li clusters as a function of size have been identified via simulated annealing. For N>21, the large $p$ character of Li leads to unexpected ionic structures. At N~25, a packing pattern based on interpenetrating 13-atom icosahedra and similar to that of Na and K appears. This pattern persists until at N=5

A. J. Roberts

Centre manifold techniques are used to derive rationally a description of the dynamics of thin films of fluid. The derived model is based on the free-surface $η(x,t)$ and the vertically averaged horizontal velocity $\avu(x,t)$. The approach appears to converge well and has significant differences from conventional depth-averaged models.

C. Alcock, R. A. Allsman, T. S. Axelrod, D. P. Bennett

The detection of microlensing has opened the way for the development of new methods in galactic astronomy. This series of papers investigates what microlensing can teach us about the structure and shape of the dark halo. In this paper we present formulas for the microlensing rate, optical depth and event duration distributions for a simple set of axisymmetri

F. DePaolis, G. Ingrosso, Ph. Jetzer, M. Roncadelli

The recent observations of microlensing events in the LMC by the MACHO and EROS collaborations suggest that an important fraction of the galactic halo is in the form of Massive Halo Objects (MHO) of about 0.1 M_{\odot}. Here, we argue that the galactic halo is mainly baryonic and that besides MHO also H_2 molecular clouds may significantly contribute to it.

Michael I. Eides, Howard Grotch

New corrections to the energy of $S$-levels of positronium of order $mα^6$ which are as large as several hundred kilohertz are obtained. A new recoil correction of order $α(Zα)^5(m/M)m$ to the Lamb shift in hydrogen is calculated. This correction turns out to be too small from the phenomenological point of view.

Kai T. Hansen

We discuss the bifurcation structure of homoclinic orbits in bimodal one dimensional maps. The universal structure of these bifurcations with singular bifurcation points and the web of bifurcation lines through the parameter space are described. The bifurcations depend on two parameters (codimension 2 bifurcations). We find the bifurcation lines exactly in a

Jemal Guven, Niall Ó Murchadha

We continue our investigation of the configuration space of general relativity begun in I (gr-qc/9411009). Here we examine the Hamiltonian constraint when the spatial geometry is momentarily static (MS). We show that MS configurations satisfy both the positive quasi-local mass (QLM) theorem and its converse. We derive an analytical expression for the spatial

Jemal Guven, Niall Ó Murchadha

We examine the constraints of spherically symmetric general relativity with one asymptotically flat region, exploiting both the traditional metric variables and variables constructed from the optical scalars. With respect to the latter variables, there exist two linear combinations of the Hamiltonian and momentum constraints which are related by time reversa

C. Giunti, C. W. Kim, J. D. Kim

Motivated by the indication that both the atmospheric and the solar neutrino puzzles may simultaneously be solved by (vacuum as well as matter-induced resonant) oscillations of two generations of neutrinos with large mixing, we have analyzed the data on the atmospheric and solar neutrinos assuming that all {\it three} neutrinos are maximally mixed. It is sho

Michael R. Douglas

We treat the stochastic equation for large N master fields proposed by Greensite and Halpern using a construction of master fields modelled after work of Voiculescu, and show that it contains the same information as the usual factorized Schwinger-Dyson equations.

A. D. Rutenberg

I comment on a paper by S. B. Goryachev [PRL vol 72, p.1850 (1994)] that presents a theory of non-equilibrium dynamics for scalar systems quenched into an ordered phase. Goryachev incorrectly applies only a global conservation constraint to systems with local conservation laws.

Graziano Crasta, Annalisa Malusa

The aim of this paper is to give an existence result for a class of one-dimensional, non-convex, non-coercive problems in the Calculus of Variations. The main tools for the proof are an existence theorem in the convex case and the closure of the convex hull of the epigraph of functions strictly convex at infinity.

N. I. Chernov, Serge Troubetzkoy

In \cite{Ch91a} it was shown that the billiard ball map for the periodic Lorentz gas has infinite topological entropy. In this article we study the set of points with infinite Lyapunov exponents. Using the cell structure developed in \cite{BSC90,Ku} we construct an ergodic invariant probability measure with infinite topological entropy supported on this set.

Emanuel Knill

An instance of a group testing problem is a set of objects $\cO$ and an unknown subset $P$ of $\cO$. The task is to determine $P$ by using queries of the type ``does $P$ intersect $Q$&#39;&#39;, where $Q$ is a subset of $\cO$. This problem occurs in areas such as fault detection, multiaccess communications, optimal search, blood testing and chromosome mappin

Francesc Comellas, J. Gómez

In this paper we give graphs with the largest known order for a given degree $Δ$ and diameter $D$. The graphs are constructed from Moore bipartite graphs by replacement of some vertices by adequate structures. The paper also contains the latest version of the $(Δ, D)$ table for graphs.

L. V. Avdeev, D. I. Kazakov, M. Yu. Kalmykov

We investigate the consistency of the background-field formalism when applying various regularizations and renormalization schemes. By an example of a two-dimensional $σ$ model it is demonstrated that the background-field method gives incorrect results when the regularization (and/or renormalization) is noninvariant. In particular, it is found that the cut-o

E. Elizalde, S. D. Odintsov

We calculate the quantum corrections to the entropy of a very large black hole, coming from the theory of a $D$-dimensional, non-critical bosonic string. We show that, for $D >2$, as a result of modular invariance the entropy is ultraviolet finite, although it diverges in the infrared (while for $D=2$ the entropy contains both ultraviolet and infrared diverg

G. V. Grigoryan, R. P. Grigoryan, G. A. Sarkissian

The pseudoclassical hamiltonian and action of the $D=2n$ dimensional Dirac particle with anomalous magnetic moment interacting with the external Yang-Mills field are found. The Bargmann-Michel-Telegdi equation of motion for the Pauli-Lubanski vector is deduced. The canonical quantization of $D=2n$ dimensional Dirac spinning particle with anomalous magnetic m

P. Brax, M. Chemtob

We examine for standard-like orbifold compactification models the constraints due to quarks and leptons generation non-universality of soft supersymmetry breaking interactions. We follow the approach initiated by Ibanez and Lust and developed by Brignole, Ibanez and Munoz. The breaking of supersymmetry is represented in terms of dilaton and moduli auxiliary

Rajesh Gopakumar, David J. Gross

The basic concepts of non-commutative probability theory are reviewed and applied to the large $N$ limit of matrix models. We argue that this is the appropriate framework for constructing the master field in terms of which large $N$ theories can be written. We explicitly construct the master field in a number of cases including QCD$_2$. There we both give an

I. Antoniadis, T. R. Taylor

We give a model-independent discussion of fermion masses in four-dimensional heterotic superstring theories. We discuss the tree level contributions and quantum corrections, including one-loop threshold effects and masses generated as a result of non-perturbative supersymmetry breaking. We also point out that superstring models give rise to a generic $μ$-ter

A. Ringwald, F. Schrempp

We present a first status report on a broad and systematic study of possible manifestations of QCD-instantons at HERA. Considerable motivation comes from the close analogy between instanton-induced $B+L$ violation in electroweak processes and effects of QCD-instantons in deep inelastic scattering. We concentrate on the high multiplicity final state structure

Jean-Marc Richard

We review some rigourous consequences of flavour independence on the spectrum and properties of hadrons in potential models, with emphasis on hadrons with two heavy quarks, such as $(b\bar c)$ mesons and $(QQq)$ baryons.