March 1995 arXiv papers — page 7

James A. Rome

Stellarator News, an international journal of the stellarator community, is Published by Fusion Energy Division, Oak Ridge National Laboratory, James A. Rome, Editor In the March 1995 issue . . . **** Exerpts from the U.S. Congress Office of Technology Assment report on TPX and Alternate Concepts. **** Edge transport and turbulence studies on U-3M The turbul

David Seibert

Are heavy quarks produced thermally or only by hard parton collisions? What is the probability that a produced heavy quark or antiquark is observed in a given resonance?

Iris Inbar, R. E. Cohen

Using the non-empirical Variational Induced Breathing (VIB) model, the thermal properties of periclase (MgO) under high pressures and temperatures are investigated using molecular dynamics, which includes all anharmonic effects. Equations of state for temperatures up to 3000K and pressures up to 310 GPa were calculated. Bulk modulus, thermal expansivity, And

H. Hakkinen, M. Manninen

Ab initio molecular dynamics is used to study deformations of sodium clusters at temperatures $500\cdots 1100$ K. Open-shell Na$_{14}$ cluster has two shape isomers, prolate and oblate, in the liquid state. The deformation is stabilized by opening a gap at the Fermi level. The closed-shell Na$_8$ remains magic also at the liquid state.

Efthimios Kaxiras

The stability of interfaces and the mechanisms of thin film growth on semiconductors are issues of central importance in electronic devices. These issues can only be understood through detailed study of the relevant microscopic processes. Experimental studies are able to provide detailed, atomic scale information for model systems. Theoretical analysis of ex

Saharon Shelah

We give a solution stated in the title to problem 3 of part 1 of the problems listed in the book of Eklof and Mekler [EM],(p.453). There, in pp. 241-242, this is discussed and proved in some cases. The existence of strongly lambda-free ones was proved earlier by the criteria in [Sh:161] in [MkSh:251]. We can apply a similar proof to a large class of other va

Carolyn Gordon, Yiping Mao

Two Riemannian manifolds are said to have $C^k$-conjugate geodesic flows if there exist an $C^k$ diffeomorphism between their unit tangent bundles which intertwines the geodesic flows. We obtain a number of rigidity results for the geodesic flows on compact 2-step Riemannian nilmanifolds: For generic 2-step nilmanifolds the geodesic flow is $C^2$ rigid. For

Josef Schoenbrunner

Data structures that realize a dictionary are characterized by three basic instructions: (1) Insert (a new entry <key,value>). (2) Search by a key, returning the associated value. (3) Delete an entry. Known realizations are hashing schemes and various types of search trees. Time complexity of the fundamental operations is measured as a function of the number

Giuliano Preparata, She-Sheng Xue

A possible ground state of Quantum Gravity is Wheeler&#39;s ``space-time foam&#39;&#39;, which can be modeled as a ``Planck-lattice&#39;&#39;, a space-time cubic lattice of lattice constant $a_P\simeq 10^{33}$cm, the Planck length. I analyse the structure of the Standard Model defined on the Planck Lattice, in the light of the ``no-go&#39;&#39; theorem of Ni

D. G. Barci, L. E. Oxman, M. Rocca

We consistently quantize a class of relativistic non-local field equations characterized by a non-local kinetic term in the lagrangian. We solve the classical non-local equations of motion for a scalar field and evaluate the on-shell hamiltonian. The quantization is realized by imposing Heisenberg&#39;s equation which leads to the commutator algebra obeyed b

D. G. Barci, L. E. Oxman

We show the relationship between a fluid of particles having charge and magnetic moment in $2+1$ dimensional electromagnetism and the Chern-Simons statistical field. The matter current which is minimally coupled to the electromagnetic field has two parts: the global electromagnetic current, and the corresponding topological current. The topological current i

Nathan Berkovits

Using the topological techniques developed in an earlier paper with Vafa, a field theory action is constructed for any open string with critical N=2 worldsheet superconformal invariance. Instead of the Chern-Simons-like action found by Witten, this action resembles that of a Wess-Zumino-Witten model. For the N=2 string which describes (2,2) self-dual Yang-Mi

U. Baur, D. Zeppenfeld

The naive implementation of finite width effects in processes involving unstable particles can violate gauge invariance. For the example of radiative $W$ production and decay, $q\bar q&#39; \to \ellνγ$, at tree level, it is demonstrated how gauge invariance is restored by including the imaginary part of triangle graphs in addition to resumming the imaginary

Daniel Ng

We examine the effect of new physics on the $R_b \equiv Γ(Z\rightarrow \bar{b}b)/Γ(Z\rightarrow {\rm hadrons})$. Conditions for large contributions are derived.

Keith A. Olive

The possible role of supersymmetry in our understanding of big bang baryogenesis and cosmological dark matter is explored. The discussion will be limited to the out-of equilibrium decay scenario in SUSY GUTs, the decay of scalar condensates, and lepto-baryogenesis as a means for generating the observed baryon asymmetry. Attention will also be focused on neut

Myron Bander, A. Subbaraman

We look for the existence of stable (by strong interactions) tetraquarks, mesons containing two heavy antiquarks and two light quarks, specifically a $|{\bar b}{\bar b}qq\rangle$ state. This state is viewed as two $|{\bar b}q\rangle $ particles bound by a potential due to the exchange of the four light pseudoscalar and vector mesons, namely the $π,\ η,\ ρ$ a

Vittorio Del Duca

We give a unified description of tree-level multigluon amplitudes in the high-energy limit. We represent the Parke-Taylor amplitudes and the Fadin-Kuraev-Lipatov amplitudes in terms of color configurations that are ordered in rapidity on a two-sided plot. We show that for the helicity configurations they have in common the Parke-Taylor amplitudes and the Fad

Keith A. Olive

The current status of big bang nucleosynthesis and its implications for physics beyond the standard model is reviewed. In particular, limits on the effective number of neutrino flavors and extra Z gauge boson masses are updated.

Giuliano Preparata, She-Sheng Xue

Proceeding in our research programme on the Standard Model (SM) on a Planck lattice (PLSM) we analyse the emergence of the quark masses through a ``superconducting&#39;&#39; mechanism of spontaneous violation of the chiral symmetry of the Standard Model. Due to the peculiar structure of the lattice coupling of the $W^\pm$ gauge bosons, we discover four new r

The MILC Collaboration, C. Bernard, T. Blum, A. De

Preliminary results from the MILC collaboration for $f_B$, $f_{B_s}$, $f_D$, $f_{D_s}$ and their ratios are presented. We compute in the quenched approximation at $β=6.3$, 6.0 and 5.7 with Wilson light quarks and static and Wilson heavy quarks. We attempt to quantify all systematic errors other than quenching, and have a first indication of the size of quenc

Kimmo Kainulainen

I show that a cosmological baryon asymmetry generated at the GUT scale is in general safe against washout due to sphalerons and generic $B$- or $L$-violating effects. This result is mainly due to the (almost) conserved number of right-handed electrons at high temperatures $T \gsim {\cal O}(10) $ TeV, but also the mass corrections, in particular the thermal m

M. Alberg, J. Ellis, D. Kharzeev

We point out that the measurement of target spin depolarization $D_{nn}$ in the $\bar{p}p\to\barΛΛ$ reaction may test dynamical mechanisms invoked to explain the proton spin puzzle revealed by polarized deep--inelastic scattering experiments. In particular, models with {\it negatively} polarized $\bar{s}s$ pairs in the proton wave function predict $D_{nn}<0$

Cai-Dian Lu, Jing-Liang Hu, Chongshou Gao

We introduce an anomalous top quark coupling (right-handed current) into Standard Model Lagrangian. Based on this, a more complete calculation of $b \to sγ$ decay including leading log QCD corrections from $m_{top}$ to $M_W$ in addition to corrections from $M_{W}$ to $m_b$ is given. The inclusive decay rate is found to be suppressed comparing with the case w

Howard D. Trottier

The fields generated by ``quarks&#39;&#39; in the adjoint representation of SU(2) color are analyzed in the scaling region of the four-dimensional lattice theory. Evidence of vacuum screening of adjoint quarks is obtained from a comparison of quark-antiquark ($Q \bar Q$) flux-tubes for quarks in the adjoint (``isospin&#39;&#39; $j=1$) and fundamental ($j=1/2

Peter Anninos, Karen Camarda, Joan Masso, Edward Seidel

We report on a new 3D numerical code designed to solve the Einstein equations for general vacuum spacetimes. This code is based on the standard 3+1 approach using cartesian coordinates. We discuss the numerical techniques used in developing this code, and its performance on massively parallel and vector supercomputers. As a test case, we present evolutions f

Miguel A. Martin-Delgado, German Sierra

We propose a perturbative-variational approach to interacting fermion systems on 1D and 2D lattices at half-filling. We address relevant issues such as the existence of Long Range Order, quantum phase transitions and the evaluation of ground state energy. In 1D our method is capable of unveiling the existence of a critical point in the coupling constant at $

Leon Balents, David R. Nelson

A flux liquid can condense into a smectic crystal in a pure layered superconductor with the magnetic field oriented nearly parallel to the layers. Similar order can arise in low temperature $^4$He films with a highly anisotropic periodic substrate potential. If the smectic order is commensurate with the layering, this periodic array is {\sl stable} to quench

Thomas Wichmann, Achille Giacometti, K. P. N. Murthy

The escape probability $ξ_{x}$ from a site $x$ of a one-dimensional disordered lattice with trapping is treated as a discrete dynamical evolution by random iterations over nonlinear maps parametrized by the right and left jump probabilities. The invariant measure of the dynamics is found to be a multifractal. However the measure becomes uniform over the supp

M. V. Feigel&#39;man, V. B. Geshkenbein, A. I. Larkin, V. M. Vinokur

A novel mechanism for the sign change of the Hall effect in the flux flow region is proposed. The difference $δn $ between the electron density at the center of the vortex core and that far outside the vortex causes the additional contribution to the Hall conductivity $δσ_{xy}=-δn ec/B$. This contribution can be larger than the conventional one in the dirty

C. Vermeulen, W. Barford, E. R. Gagliano

Exact diagonalisations of the extended Hubbard model are performed. In the insulating regime it is shown that the nearest neighbour copper-oxygen repulsion, $V$, leads to Frenkel excitons in the charge transfer gap at values of $V$ of the order of copper-oxygen hybridisation, $t$. In the metallic regime it is shown that the static charge-transfer and density

A. Hädicke, W. Krech

Single-charge tunneling in ultrasmall voltage biased SIS junctions in a high-impedance electromagnetic environment is considered. The Cooper pair current is calculated at T=0 on the basis of the elementary tunnel Hamiltonian for quasiparticles. Therefore, the transfer of Cooper pairs emerges automatically as an effect of higher order perturbation theory. The

Samuele Bottani

It is shown that globally-coupled oscillators with pulse interaction can synchronize under broader conditions than widely believed from a theorem of Mirollo \& Strogatz \cite{MirolloII}. This behavior is stable against frozen disorder. Beside the relevance to biology, it is argued that synchronization in relaxation oscillator models is related to Self-Organi

Jens Fricke, Peter Kopietz

We show by means of simple exact manipulations that the thermodynamic persistent current $I ( ϕ, N )$ in a mesoscopic metal ring threaded by a magnetic flux $ϕ$ at constant particle number $N$ agrees even beyond linear response with the dynamic current $I_{dy} ( ϕ, N )$ that is defined via the response to a time-dependent flux in the limit that the frequency

P. G. Silvestrov

The statistics of random band--matrices with width and strength of the band slowly varying along the diagonal is considered. The Dyson equation for the averaged Green function close to the edge of spectrum is reduced to the Painlevé I equation. The analytical properties of the Green function allow to fix the solution of this equation. The former appears to b

David J. Christini, James J. Collins

Chaos control techniques have been applied to a wide variety of experimental systems, including magneto-elastic ribbons, lasers, chemical reactions, arrhythmic cardiac tissue, and spontaneously bursting neuronal networks. An underlying assumption in all of these studies is that the system being controlled is chaotic. However, the identification of chaos in e

Ian Smail, Alan Dressler, Jean-Paul Kneib, Richard S. Ellis

We present HST imaging of eight spectroscopically-confirmed giant arcs, pairs and arclets. These objects have all been extensively studied from the ground and we demonstrate the unique advantages of HST imaging in the study of such features by a critical comparison of our data with the previous observations. In particular we present new estimates of the core

A. C. Quillen, C. B. Quillen

In this paper, by considering a simple fluid model, we investigate the role of phase transitions in the ISM on the galaxy scale gas dynamics. Cooling and heating timescales in the ISM are typically shorter than typical galactic rotation timescales, so the individual phases in the ISM can be assumed to be in temperature equilibrium with the radiation field. U

Y. D. Mayya

A stellar population synthesis model, suitable for comparison with Giant Extragalactic HII Regions (GEHRs), is constructed incorporating the recent developments in modelling stellar evolution by Maeder and co-workers and stellar atmospheres by Kurucz. A number of quantities suitable for comparison with broad band data of GEHRs in visible and near infrared pa

Steven D. Kawaler

During the final evolution of most stars, they shed their outer skin and expose their core of the hot ashes of nuclear burning. As these hot and very dense cores cool into white dwarf stars, they go through episodes of multiperiodic, nonradial g-mode pulsation. The tools of stellar seismology allow us to use the pulsation spectra as powerful probes into the

Robert Blum, John Carr, Kris Sellgren, Don Terndrup

We present radial velocities for approximately 40 stars in each of three optically obscured, off-axis, fields toward the Galactic bulge. Combined with the data presented by Blum et al. (1994), we now have mean radial velocities and radial velocity dispersions in four fields towards the Galactic bulge. These four fields lie nearly along an axis whose position

Ivan Cherednik

This paper contains the proof of Macdonald&#39;s duality and evaluation conjectures, the definition of the difference Fourier transform, the recurrence theorem generalizing Pieri rules, and the action of GL(2,Z) on the Macdonald polynomials at roots of unity.

William H. Kinney, K. T. Mahanthappa

``Natural&#39;&#39; inflationary theories are a class of models in which inflation is driven by a pseudo-Nambu-Goldstone boson. In this paper we consider two models, one old and one new, in which the potential for inflation is generated by loop effects from a fermion sector which explicitly breaks a global $U(1)$ symmetry. In both models, we retrieve the ``s

Varghese John, Nguyen Ai Viet, Kameshwar C. Wali

Considering bilayer systems as extensions of the planar ones by an internal space of two discrete points, we use the ideas of Noncommutative Geometry to construct the gauge theories for these systems. After integrating over the discrete space we find an effective $2+1$ action involving an extra complex scalar field, which can be interpreted as arising from t

I. Androutsopoulos, G. D. Ritchie, P. Thanisch

This paper is an introduction to natural language interfaces to databases (NLIDBs). A brief overview of the history of NLIDBs is first given. Some advantages and disadvantages of NLIDBs are then discussed, comparing NLIDBs to formal query languages, form-based interfaces, and graphical interfaces. An introduction to some of the linguistic problems NLIDBs hav

Steven Carlip

These lectures briefly review our current understanding of classical and quantum gravity in three spacetime dimensions, concentrating on the quantum mechanics of closed universes and the (2+1)-dimensional black hole. Three formulations of the classical theory and three approaches to quantization are discussed in some detail, and a number of other approaches

J. L. Alonso, J. M. Carmona, J. Clemente Gallardo, L. A. Fernandez

We study the phase diagram of the four dimensional Ising model with first and second neighbour couplings, specially in the antiferromagnetic region, by using Mean Field and Monte Carlo methods. From the later, all the transition lines seem to be first order except that between ferromagnetic and disordered phases in a region including the first-neighbour Isin

Francois Gygi

We present a new formulation of ab initio molecular dynamics which exploits the efficiency of plane waves in adaptive curvilinear coordinates, and thus provides an accurate treatment of first-row elements. The method is used to perform a molecular dynamics simulation of the CO_2 molecule, and allows to reproduce detailed features of its vibrational spectrum

F. Belgiorno, S. Liberati

In this work we review, in the framework of the so-called brick wall model, the divergence problem arising in the one loop calculations of various thermodynamical quantities, like entropy, internal energy and heat capacity. Particularly we find that, if one imposes that entanglement entropy is equal to the Bekenstein-Hawking one, the model gives problematic

David H. Adams, Siddhartha Sen

An extension of the method and results of A. Schwarz for evaluating the partition function of a quadratic functional is presented. This enables the partition functions to be evaluated for a wide class of quadratic functionals of interest in topological quantum field theory, for which no other method has previously been available. In particular it enables the

S. A. Coon, M. T. Peña, D. O. Riska

The three nucleon interaction that arises from pion and the effective scalar and vector meson exchange components of the nucleon-nucleon interaction is constructed and shown to be repulsive. Using several wavefunction models we show that this interaction reduces the calculated binding energy of the trinucleons by about 200 keV. The contributions of intermedi

R. P. Manvelyan, D. H. Tchrakian

We present a hierarchy of gauged Grassmanian models in $4p$ dimensions, where the gauge field takes its values in the $2^{2p- 1}\times 2^{2p-1}$ chiral representation of SO(4p). The actions of all these models are absolutely minimised by a hierarchy of self-duality equations, all of which reduce to a single pair of coupled ordinary differential equations whe

Martin White, Emory F. Bunn

With the advent of the COBE detection of fluctuations in the Cosmic Microwave Background radiation, the study of inhomogeneous cosmology has entered a new phase. It is now possible to accurately normalize fluctuations on the largest observable scales, in the linear regime. In this paper we present a model-independent method of normalizing theories to the ful

R. M. Kashaev

It is shown that the Heisenberg double has a canonical element, satisfying the pentagon relation. From a given invertible constant solution to the pentagon relation one can restore the structure of the underlying algebras. Drinfeld double can be realized as a subalgebra in the tensor square of the Heisenberg double. This enables one to write down solutions t

David Seibert, Charles Gale

We estimate the numbers and mass spectra of observed lepton and kaon pairs produced from $ϕ$ meson decays in the central rapidity region of an Au+Au collision at lab energy 11.6 GeV/nucleon. The following effects are considered: possible mass shifts, thermal broadening due to collisions with hadronic resonances, and superheating of the resonance gas. Changes

Paul Feit

This work concludes a series of four papers on the foundational theory of orbifolds and stacks. We apply the abstract theory, developed in its predecessors, to orbifolds derived from manifolds. Specifically, we show how the very concrete topological base spaces associated to such orbifolds can be described and manipulated in our universal language. At the sa

Guillermo Cortiñas, Susan C. Geller, Charles A. Weibel

We propose an Artinian version of Berger&#39;s Conjecture for curves, concerning the module of Kähler differentials of an algebra. Our version implies Berger&#39;s Conjecture in characteristic 0. We establish our Artinian Berger Conjecture in a number of cases, and prove that Berger&#39;s Conjecture holds for curve singularities whose conductor ideal contain

B. S. Balakrishna, K. T. Mahanthappa

A generalization of the non-Abelian version of the $CP^{N-1}$ models (also known as Grassmannian models) is presented. The generalization helps accommodate a partial breaking of the non-Abelian gauge symmetry. Constituents of the composite gauge fields, in many cases, are naturally constrained to belong to an anomaly free representation which in turn generat

Alexander Burinskii

The Kerr solution is considered as a soliton-like background for spinning elementary particles. Two stringy structures may be found in the Kerr geometry, one string is real and another one is complex. The main attention in this paper is paid to the complex string, which is connected with the Lind-Newman representation of the Kerr metric source as an object w

A. H. Chamseddine, J. Fröhlich, O. Grandjean

We study the Riemannian aspect and the Hilbert-Einstein gravitational action of the non-commutative geometry underlying the Connes-Lott construction of the action functional of the standard model. This geometry involves a two-sheeted, Euclidian space-time. We show that if we require the space of forms to be locally isotropic and the Higgs scalar to be dynami

Evgeni E. Donets, Dmitri V. Gal&#39;tsov

The effect of the Gauss--Bonnet term on the SU(2) non--Abelian regular stringy sphaleron solutions is studied within the non--perturbative treatment. It is found that the existence of regular solutions depends crucially on the value of the numerical factor $β$ in front of the Gauss--Bonnet term in the four--dimensional effective action. Numerical solutions a

Robert D. Pisarski

I discuss several topics in the applications of chiral symmetry at nonzero temperature, including: where the rho goes, disoriented chiral condensates, and the phase diagram for $QCD$ with $2+1$ flavors. (Based upon talks presented at the &#34;Workshop on Finite Temperature $QCD$&#34;, Wuhan, P.R.C., April, 1994.)

Robert D. Pisarski

I discuss different models which predict changes in the mass of the thermal $ρ$ field. I emphasize that while the predictions are strongly model dependent, nevertheless substantial shifts in the thermal $ρ$ mass are expected to occur at the point of phase transition. As long as the thermal $ρ$ peak does not become too broad, this should provide a striking si

Robert D. Pisarski

If the phase transition of $QCD$ at nonzero temperature is dominated by the (approximate) restoration of chiral symmetry, then the transition might be characterized using a gauged linear sigma model. Assuming that vector meson dominance holds, such sigma models predict that at the temperature of chiral restoration, the pole mass of the thermal $ρ$ meson is g

Paul Langacker

The theoretical motivations, experimental searches/hints, and implications of neutrino mass are surveyed.

M. Gourdin, Y. Y. Keum, X. Y. Pham

We propose a phenomenological two component model describing the decay amplitude of the process $D_s^{+} \ra 3 π$, whose rate has been found surprisingly large. The first component is a constant background $F_{NR}$, and the second one is a Breit-Wigner type amplitude associated to a quasi two body $f_0(980)$ $π^{+}$ state. We show that it is possible to repr

Z. FODOR

The electroweak phase transition is studied at finite temperature. The effective action is given to higher orders, including wave function correction factors and the full $g^4,λ^2$ effective potential. An upper bound for the Higgs mass $m_{H} \approx 70\ GeV$ is concluded for the reliability of the perturbative approach. A gauge invariant treatment of the ph

Robert Eckardt, J&#34;org Hansper, Manfred F. Gari

Using the criteria of simplicity, positivity, smoothness and process- independence of construction, we find a non-polynomial model for the quark distribution amplitude of the nucleon that is in agreement with QCD sum-rule constraints. This simpler (&#34;haplousterotic&#34;) model solves some of the problems connected with the longitudinal momentum dependence

B. Ananthanarayan, P. N. Pandita

We consider the supersymmetric extension of the standard model with an additional singlet $S$, the Non-Minimal Supersymmetric Standard Model (NMSSM), in the limit $\tanβ\simeq m_t/m_b$. We embed this model in a supergravity framework with universal boundary conditions and analyze the renormalization group improved tree-level potential. We examine the relatio

A. A. Penin, A. A. Pivovarov

We make an attempt to clarify the role of the annihilation or &#34;penguin&#34; mode in the description of the $K\rightarrowππ$ decay within the Standard Model. The attention is concentrated on new operators in the effective $ΔS=1$ Hamiltonian and the violation of factorization for mesonic matrix elements of the local four-quark operators. We propose a regul

A. Khodjamirian, R. Rückl

We discuss applications of QCD sum rules on the light-cone to the form factors of the exclusive transitions $B \rightarrow π$ and $D\rightarrow π$, and to the $B^*B π$ and $D^*D π$ coupling constants. In the light of our results we examine the pole dominance model for these form factors. A first estimate is given on the nonfactorizable amplitude of the decay

W. J. Stirling

The rapid increase of the e+e- --> W+W- cross section in the threshold region provides a method for measuring M(W) at LEP2. The dependence of the theoretical cross section -- including the effects of the finite W width, Coulomb interactions and initial state radiation -- on the collider energy and on the mass and width of the W is investigated in order to de

Morimitsu Tanimoto

We study the see-saw enhancement mechanism in presence of the right-handed phases of the Dirac neutrino mass matrix and the Majorana mass matrix. The enhancement condition given by Smirnov is modified. We point out that the see-saw enhancement could be obtained due to the right-handed phases even if the Majorana matrix is proportional to the unit matrix. We

Ina Sarcevic

We present results on rapidity and transverse momentum distributions of inclusive charm quark production in hadronic and heavy-ion collisions at RHIC and LHC energies, including the next-to-leading order, $O(α_s^3)$, radiative corrections and the nuclear shadowing effect. We determine the hadronic and the {\it effective} (in-medium) K-factor for the differen

D. O. Caldwell, R. N. Mohapatra

The cosmological model in which 20% of the dark matter is shared by two nearly equal mass neutrinos fits the structure of the universe on all scales. This has been motivated a $ν_μ$-$ν_τ$ oscillation explanation of the deficit of atmospheric muon neutrinos. If the observed ratio of atmospheric $nu_μ$ to $ν_e$ has an alternative explanation, the cosmological

Z. FODOR

The finite temperature electroweak phase transition is studied on the lattice. The results of the simulations obtained by the 3-dimensional effective theories and the 4-dimensional SU(2)-Higgs model are reviewed.

R. A. Puntigam, E. Schrüfer, F. W. Hehl

We present a small computer algebra program for use in Maxwell&#39;s theory. The Maxwell equations and the energy-momentum current of the electromagnetic field are formulated in the language of exterior differential forms. The corresponding program can be applied (in the presence of a gravitational field) in curved Riemannian spacetime as well as in flat Min

Hon-kit Wai

In this paper, we extend the Witten-Helffer-Sjöstrand theory from Morse functions to generalized Morse functions. In this case, the spectrum of the Witten deformed Laplacian $Δ(t)$, for large t, can be seperated into the small eigenvalues (which tend to 0 as $t\rightarrow\infty$), large and very large eigenvalues (both of which tend to $\infty$ as $t\rightar

Fausto Borgonovi, Italo Guarneri

We compare the properties of transmission across one-dimensional finite samples which are associated with two types of &#34;quantum diffusion&#34;, one related to a classical chaotic dynamics, the other to a multifractal energy spectrum. We numerically investigate models exhibiting one or both of these features, and we find in all cases an inverse power law

Fausto Borgonovi, Dima L. Shepelyansky

We study the effect of coherent propagation of two interacting particles in a disordered potential. The dependence of the enhancement factor for coherent localization length due to interaction is investigated numerically in the model of quantum chaos. The effect of interaction for two particles in many dimensions is also discussed.

Enzo Marinari, Remi Monasson, Juan J. Ruiz-Lorenzo

We discuss the behavior of a crystalline surface with a disordered substrate. We focus on the possible existence of a {\em super-rough} glassy phase, with height-height correlation functions which vary as the square logarithm of the distance. With numerical simulations we establish the presence of such a behavior, that does not seem to be connected to finite

J. Lee, M. A. Novotny, P. A. Rikvold

We propose two different macroscopic dynamics to describe the decay of metastable phases in many-particle systems with local interactions. These dynamics depend on the macroscopic order parameter $m$ through the restricted free energy $F(m)$ and are designed to give the correct equilibrium distribution for $m$. The connection between macroscopic dynamics and

David Milward

The paper describes a parser for Categorial Grammar which provides fully word by word incremental interpretation. The parser does not require fragments of sentences to form constituents, and thereby avoids problems of spurious ambiguity. The paper includes a brief discussion of the relationship between basic Categorial Grammar and other formalisms such as HP

David Milward

Despite the large amount of theoretical work done on non-constituent coordination during the last two decades, many computational systems still treat coordination using adapted parsing strategies, in a similar fashion to the SYSCONJ system developed for ATNs. This paper reviews the theoretical literature, and shows why many of the theoretical accounts actual

T. R. Bedding, H. Kjeldsen

We recently reported strong evidence for solar-like oscillations in the G0 IV star eta Boo (Kjeldsen et al. 1995, AJ 109, 1313). We measured small temperature fluctuations produced by oscillations through their effect on the equivalent widths of the Balmer lines. Here we address several issues that were raised at this conference. In particular, we show a pow

Francesca Matteucci, Brad K. Gibson

We study the origin of iron and alpha-elements (O, Mg, Si) in clusters of galaxies. In particular, we discuss the [O/Fe] ratio and the iron mass-to-luminosity ratio in the intracluster medium (ICM) and their link to the chemical and dynamical evolution of elliptical and lenticular galaxies. We adopt a detailed model of galactic evolution incorporating the de

Mordehai Milgrom

Gerhard had recently analyzed the data on seven dwarf spheroidals, and concluded that these disagree with the predictions of MOND. We contend that this conclusion is anything but correct. With new data for three of the dwarfs the observations of all dwarfs are in compelling agreement with the predictions of MOND. Gerhard found MOND M/L values that fall aroun

G. Laumon, M. Rapoport

In this note we show that the Langlands lemma from the theory of Eisenstein series can be used to invert the recursion relation for the Poincaré series of the open substack of semi-stable $G$-bundles which was established by Atiyah/Bott and Harder/Narasimhan.

Flavio Angelini

We give an elementary algebraic proof of some asymptotic estimates (called by Demailly asymptotic Morse inequalities) for the dimensions of cohomology groups of the difference of two ample line bundles on a smooth complex projective variety of any dimension.

David Milward, Robin Cooper

Why should computers interpret language incrementally? In recent years psycholinguistic evidence for incremental interpretation has become more and more compelling, suggesting that humans perform semantic interpretation before constituent boundaries, possibly word by word. However, possible computational applications have received less attention. In this pap

Isaac M. Held, Vitaly D. Larichev

The scaling argument developed by Larichev and Held (1995) for eddy amplitudes and fluxes in a horizontally homogeneous, two-layer model on an f-plane is extended to a beta-plane. In terms of the non-dimensional number x = U/(beta*lambda^2), where lambda is the deformation radius and U is the mean thermal wind, the result for the RMS eddy velocity V, the cha

M. Ameduri, R. Konik, A. LeClair

We study bosonization of the sine-Gordon theory in the presence of boundary interactions at the free fermion point. In this way we obtain the boundary S-matrix as a function of physical parameters in the boundary sine-Gordon Lagrangian. The boundary S-matrix can be matched onto the solution of Ghoshal and Zamolodchikov, thereby relating the formal parameters

Jacek Dziarmaga

We investigate dynamics of overlapping vortices in the nonlinear Schrödinger equation, the nonlinear heat equation and in the equation with an intermediate Schrödinger-diffusion dynamics. Because of formal similarity on a perturbative level we discuss also the nonlinear wave equation (Goldstone model). Special solutions are found like vortex helices, double-

V. P. Karassiov

Within the new description of the polarization structure of quantum light (given in Part I) some types of generalized coherent states related to the polarization SU(2) group are examined. With their help we give a quasiclassical description of polarization properties of light fields and discuss the concept of squeezing and uncertainty relations for multimode

A. V. Leonidov, P. V. Ruuskanen

We consider the dilepton emission from a dense and hot hadron gas near a critical point. The hadron gas is described as a resonance one. The dilepton spectrum generated by vector resonances is shown to be equivalent to the one generated by quarks.

Juergen Audretsch, Rainer Mueller, Markus Holzmann

For a small system the coupling to a reservoir causes energy shifts as well as transitions between the system&#39;s energy levels. We show for a general stationary situation that the energy shifts can essentially be reduced to the relaxation rates. The effects of reservoir fluctuations and self reaction are treated separately. We apply the results to a two-l

Kurt Krenn, Karl Svozil

After an elementary derivation of Bell&#39;s inequality, several forms of expectation functions for two-valued observables are discussed. Special emphasis is given to hypothetical stronger-than quantum expectation functions which give rise to a maximal violation of Bell&#39;s inequality.

Dieter Kiderlen

Diffusion coefficients are obtained from linear response functions and from the quantal fluctuation dissipation theorem. They are compared with the results of both the theory of hydrodynamic fluctuations by Landau and Lifschitz as well as the Boltzmann-Langevin theory. Sum rules related to conservation laws for total particle number, momentum and energy are

Josef Schoenbrunner

We know extensions of first order logic by quantifiers of the kind &#34;there are uncountable many ...&#34;, &#34;most ...&#34; with new axioms and appropriate semantics. Related are operations such as &#34;set of x, such that ...&#34;, Hilbert&#39;s $ε$-operator, Churche&#39;s $λ$-notation, minimization and similar ones, which also bind a variable within so

Paulo M. Sa&#39;, Antares Kleber, Jose&#39; P. S. Lemos

Three dimensional black holes in a generalized dilaton gravity action theory are analysed. The theory is specified by two fields, the dilaton and the graviton, and two parameters, the cosmological constant and the Brans-Dicke parameter. It contains seven different cases, of which one distinguishes as special cases, string theory, general relativity and a the

Burkhard Kleihaus, Jutta Kunz, Abha Sood

In the SU(3) Einstein-Skyrme system static spherically symmetric particle-like solutions and black holes exist for both the SU(2) and the SO(3) embedding. The SO(3) embedding leads to new particle-like solutions and black holes, sharing many features with the SU(2) solutions. In particular, there are always two branches of solutions, forming a cusp at a crit