April 1995 arXiv papers — page 2

B. Paczynski

Microlensing of distant stars in the Milky Way by the nearby high proper motion stars offers a direct way to precisely measure the masses of single lower main sequence stars and brown dwarfs.

Giacomo Giampieri

Recent theoretical works on alternative metric theories of gravity give greater significance to solar-system tests of General Relativity. In particular, it is suggested that the post-Newtonian parameter $γ$ ought to be determined with great precision in order to discover possible preferred frame effects or effects related to a tensor-scalar theory of gravita

Luca Amendola, Carlo Baccigalupi, Franco Occhionero

It is already understood that the increasing observational evidence for an open Universe may be reconciled with inflation if our horizon is contained inside one single huge bubble nucleated during the inflationary phase transition. In the scenario we present here, the Universe consists of infinitely many superhorizon bubbles, like our own, the distribution o

Michael Rauch, Martin G. Haehnelt

Estimates of Omega_baryon from primordial nucleosynthesis together with standard assumptions about the ionization state of low column density Lyman alpha forest clouds can be used to determine an upper limit for the cloud thickness along the line of sight. This upper limit provides significant constraints on the axis ratio of the absorbers and on the overall

C. S. Reynolds, A. C. Fabian, H. Inoue

We present {\it ASCA} observations of the Seyfert 1 galaxies Mrk~1040 and MS~0225.5+3121. Mrk~1040 was found to have decreased in flux by almost a factor of 4 since an {\it EXOSAT} observation 10\,years ago. The energy spectrum of Mrk~1040 displays complexity both at soft energies (below 0.8\thinspace keV) and at hard energies (6--7\thinspace keV). The latte

Sergey S. Kurennoy

The longitudinal and transverse coupling impedances of a small discontinuity on the accelerator chamber wall can be expressed in terms of the electric and magnetic polarizabilities of the discontinuity. The polarizabilities are geometrical factors and can be found by solving a static (electric or magnetic) problem. However, they are known in the explicit ana

Sergey S. Kurennoy, Gennady V. Stupakov

It has been shown that a small discontinuity such as an enlargement or a hole on circular waveguides can produce trapped electromagnetic modes with frequencies slightly below the waveguide cutoff. The trapped modes due to multiple discontinuities can lead to high narrow-band contributions to the beam-chamber coupling impedance, especially when the wall condu

Sergey S. Kurennoy, Robert L. Gluckstern, Gennady V. Stupakov

A general theory of the beam interaction with small discontinuities of the vacuum chamber is developed taking into account the reaction of radiated waves back on the discontinuity. The reactive impedance calculated earlier is reproduced as the first order, and the resistive one as the second order of a perturbation theory based on this general approach. The

B. Reznik

We propose an extended quantum mechanical formalism that is based on a wave operator $\vr$, which is related to the ordinary density matrix via $ρ=\vr\vr^\dagger$. This formalism allows a (generalized) unitary evolution between pure and mixed states. It also preserves much of the connection between symmetries and conservation laws. The new formalism is illus

Eckhard Meinrenken

Let $G$ be a compact connected Lie group, and $M$ a compact Hamiltonian $G$-space, with moment map $J$. For each $G$-equivariant Hermitian vector bundle $E$ over $M$, one has an associated twisted Spin-C Dirac operator, whose equivariant index is a symplectic invariant of $E$. In the present paper, we study gluing properties of the equivariant index under &#

Ian I. Kogan, Mikhail Shifman

We argue that supersymmetric gluodynamics has two phases with equivalent infrared behavior, one of which is asymptotically free and another one is superstrongly coupled in the ultraviolet domain.

E. H. Simmons, P. Cho

Strong-interaction physics that lies beyond the standard model may conveniently be described by an effective Lagrangian. The only genuinely gluonic CP-conserving term at dimension six is the three-gluon-field-strength operator $G^3$. This operator, which alters the 3-gluon and 4-gluon vertices form their standard model forms, turns out to be difficult to det

Alexander Moroz

Both the nonrelativistic scattering and the spectrum in the presence of the Aharonov-Bohm potential are analyzed. The single-particle density of states (DOS) for different self-adjoint extensions is calculated. The DOS provides a link between different physical quantities and is a natural starting point for their calculation. The consequences of an asymmetry

Bogdan A. Dobrescu

We propose a supersymmetric technicolor model in which the electroweak symmetry breaking is communicated to the quarks and leptons by technicolored $SU(2)_W$-singlet scalars. When the technifermions condense, the quarks and leptons of the third generation acquire mass. The fermions of the other generations do not couple to the technicolored scalars but they

Ben Nasatyr, Brian Steer

We extend Hitchin's results on "The self-duality equations on a Riemann surface" (Proc. LMS (3), vol. 55, 1987) to orbifold Riemann surfaces. We prove existence results for orbifold solutions of the Yang-Mills-Higgs equations and construct the moduli space of solutions. These moduli spaces provide interesting examples of non-compact hyper-Kahler

E. F. Vieira, J. D. Ponz

Along the life of the IUE project, a large archive with spectral data has been generated, requiring automated classification methods to be analyzed in an objective form. Previous automated classification methods used with IUE spectra were based on multivariate statistics. In this paper, we compare two classification methods that can be directly applied to sp

Geunbae Lee, Jong-Hyeok Lee, Sanghyun Shin

Both statistical and rule-based approaches to part-of-speech (POS) disambiguation have their own advantages and limitations. Especially for Korean, the narrow windows provided by hidden markov model (HMM) cannot cover the necessary lexical and long-distance dependencies for POS disambiguation. On the other hand, the rule-based approaches are not accurate and

Kazuo Fujikawa, L. C. Kwek, C. H. Oh

The quantum deformation of the oscillator algebra and its implications on the phase operator are studied from a view point of an index theorem by using an explicit matrix representation. For a positive deformation parameter $q$ or $q=exp(2\pi i\theta)$ with an irrational $\theta$, one obtains an index condition $\dml a - \dml a^{\dagger} = 1$ which allows on

Anirban Kundu

We consider the physics of an extra $U(1)$ gauge boson $Z'$, which can mix with $Z$ through intermediate fermion loops. The loop contribution due to the heavy top quark significantly affects the low-energy observables, and for $m_{Z'}>m_Z$, one can always adjust the shifts in these observables to be in the right direction suggested by experiments, wh

H. C. Rosu, M. Reyes, K. B. Wolf, O. Obregón

We provide a supersymmetric analysis of the Maxwell fisheye (MF) wave problem at zero energy. Working in the so-called $R_{0}=0$ sector, we obtain the corresponding superpartner (fermionic) MF effective potential within Witten's one-dimensional (radial) supersymmetric procedure.

Galin Georgiev

The standard modules for an affine Lie algebra $\ga$ have natural subquotients called parafermionic spaces -- the underlying spaces for the so-called parafermionic conformal field theories associated with $\ga.$ We study the case $\ga = \widehat{sl}(n+1,\C)$ for any positive integral level $k \geq 2.$ Generalizing the $\cal Z$-algebra approach of Lepowsky, W

M. Hoffmann, J. W. Durso, K. Holinde, B. C. Pearce

A dynamical model for S-- and P--wave correlated $2 π$ (and $K \bar K$) exchange between a kaon and a nucleon is presented, starting from corresponding $N \bar N \rightarrow K \bar K$ amplitudes in the pseudophysical region, which have been constructed from nucleon, $Δ$--isobar and hyperon ($Λ$, $Σ$) exchange Born terms and a realistic meson exchange model o

G. Q. Li, C. M. Ko

In a one-pion plus one-kaon exchange model, we calculate the kaon production cross sections in nucleon-nucleon, nucleon-delta and delta-delta interactions. We find that this model describes reasonably well the experimental data on kaon production in the proton-proton interaction. Near the kaon production threshold, the cross section obtained from this model

Genadi Levin, Sebastian van Strien

One of the main questions in the field of complex dynamics is the question whether the Mandelbrot set is locally connected, and related to this, for which maps the Julia set is locally connected. In this paper we shall prove the following Main Theorem: Let $f$ be a polynomial of the form $f(z)=z^d +c$ with $d$ an even integer and $c$ real. Then the Julia set

Roberto Floreanini, Luc Vinet

We provide an algebraic interpretation for two classes of continuous $q$-polynomials. Rogers' continuous $q$-Hermite polynomials and continuous $q$-ultraspherical polynomials are shown to realize, respectively, bases for representation spaces of the $q$-Heisenberg algebra and a $q$-deformation of the Euclidean algebra in these dimensions. A generating fu

Roberto Floreanini, Jean LeTourneux, Luc Vinet

Properties of certain $q$-orthogonal polynomials are connected to the $q$-oscillator algebra. The Wall and $q$-Laguerre polynomials are shown to arise as matrix elements of $q$-exponentials of the generators in a representation of this algebra. A realization is presented where the continuous $q$-Hermite polynomials form a basis of the representation space. V

Roberto Floreanini, Jean LeTourneux, Luc Vinet

The continuous big $q$-Hermite polynomials are shown to realize a basis for a representation space of an extended $q$-oscillator algebra. An expansion formula is algebraically derived using this model.

Pau Atela, Jun Hu

It has been known since Julia that polynomials commuting under composition have the same Julia set. More recently in the works of Baker and Eremenko, Fernández, and Beardon, results were given on the converse question: When do two polynomials have the same Julia set? We give a complete answer to this question and show the exact relation between the two probl

Hitoshi Nishino

We present interesting relationship between what are called stationary axisymmetric black hole solutions for the vacuum Einstein equations in the ordinary four-dimensions and exact solutions for self-dual Yang-Mills fields in flat $2+2$ dimensions which are nothing but the consistent backgrounds for $~N=2$~ open superstring. We show that any stationary axisy

E. Bergshoeff, E. Sezgin

We present a geometric formulation of super $p$--brane theories in which the Wess--Zumino term is $(p+1)$--th order in the supersymmetric currents, and hence is manifestly supersymmetric. The currents are constructed using a supergroup manifold corresponding to a generalization of a superalgebra which we found sometime ago. Our results generalize Siegel'

Alexander Burinskii

The Kerr solution to axidilaton gravity is analyzed in the Debney--Kerr--Schild formalism. It is shown that the Kerr principal null congruence retains its property to be geodesic and shear free, however, the axidilatonic Kerr solution is not algebraically special. A limiting form of this solution is considered near the ring-like Kerr singularity. This limiti

S. Krivonos, A. Sorin, F. Toppan

A manifestly $N=2$ supersymmetric coset formalism is introduced to describe integrable hierarchies. It is applied to analyze the super-NLS equation. It possesses an $N=2$ symmetry since it can be obtained from a manifest $N=2$ coset algebra construction. A remarkable result is here discussed: the existence of a Bäcklund transformation which connects the supe

Omer F. Dayi

Odd time was introduced to formulate the Batalin-Vilkovisky method of quantization of gauge theories in a systematic manner. This approach is presented emphasizing the odd time canonical formalism beginning from an odd time Lagrangian. To let the beginners have access to the method essential notions of the gauge theories are briefly discussed, and each step

Noriaki Ano

We study the topologically twisted osp(2|2)+osp(2|2) conformal superalgebra. The algebra includes the Lagrangians which are intrinsic to the topological field theory and composed of fermionic generators. Studying the Lagrangians through a gauge system of osp(2|2)+osp(2|2), geometrical features inherent to the algebra are revealed: a moduli space associated w

Claudio Coriano', Alan R. White

Unitarity corrections to the BFKL evolution at next to leading order determine a new component of the evolution kernel which is shown to possess conformal invariance properties. Expressions for the complete spectrum of the new component and the correction to the intercept of the pomeron trajectory are presented.

D. J. Broadhurst, A. G. Grozin

We review algorithmic methods for two-loop calculations in HQET, and the analogous methods for on-shell QCD, needed for matching HQET to QCD.

P. A. Baikov, D. J. Broadhurst

Three--loop contributions to massive QED vacuum polarization are evaluated by a combination of analytical and numerical techniques. The first three Taylor coefficients, at small $q^2$, are obtained analytically, using $d$\/--dimensional recurrence relations. Combining these with analytical input at threshold, and at large $q^2$, an accurate Padé approximatio

D. Kharzeev, H. Satz

We analyse the kinematic regimes attainable for $J/Ψ$ and $Ψ'$ production in $p-A$ collisions. With this information, we specify the requirements for an experiment to study the interaction of physical charmonium states in nuclear matter, making use of a heavy ion beam incident on a hydrogen or deuterium target.

O. W. Greenberg, R. Ray, F. Schlumpf

We derive a system of covariant single-time equations for a two-body bound state in a model of scalar fields $ϕ_1$ and $ϕ_2$ interacting via exchange of another scalar field $χ$. The derivation of the system of equations follows from the Haag expansion. The equations are linear integral equations that are explicitly symmetric in the masses, $m_1$ and $m_2$,

Daijiro Suematsu, Yoshio Yamagishi

We study the inflation due to the D-flat direction of an extra $U(1)$. This scenario is a hybrid of a right-handed sneutrino inflaton scenario and a gauge non-singlet inflaton scenario. The inflaton is a gauge non-singlet field which induces a right-handed neutrino mass spontaneously through an extra $U(1)$ D-flat direction. This right-handed neutrino mass c

P. Kroll

It is reported on predictions for the $π$-$γ$ transition form factor obtained within a perturbative approach which includes transverse momentum effects and Sudakov corrections. The results clearly favor distribution amplitudes close to the asymptotic form, $\sim x_1x_2$, and disfavor distribution amplitudes which are strongly concentrated in the end-point re

Christopher D. Carone, Hitoshi Murayama

We consider a model in which each family transforms under a different SU(3) color group. The low-energy effective theory is an extension of the Standard Model, with additional color octet gauge bosons $G_H$ with mass $M$ that couple preferentially to the third family quarks. We show that there are two distinct regions of the model's parameter space in wh

C. Alexandrou

Heavy-light bound states are studied in Lattice QCD with emphasis on parameters of the B-system relevant to experiment. Results are obtained on lattices with lattice spacings from about 0.15 fm to 0.06 fm corresponding to $β=5.74, 6.0$ and 6.26, and covering sizes from about 0.7 fm to 2 fm. From our results at the infinite quark mass limit and from propagati

Francois David

In a recent letter (hep-lat/9311019) A. Patrascioiu and E. Seiler argued that when taking into account "superinstantons configurations" the perturbative expansion and the beta-function of the two-dimensional non-linear sigma-model are modified at two loops order. I point out that: (1) perturbation theory in a superinstanton background is infra-red si

L. P. Grishchuk

It is likely that the observed large-angular-scale anisotropies in the microwave background radiation are induced by the cosmological perturbations of quantum-mechanical origin. Such perturbations are now placed in squeezed vacuum quantum states and, hence, are characterized by large variances of their amplitude. The statistical properties of the anisotropie

Ioan Kosztin, Dmitrii L. Maslov, Paul M. Goldbart

A new type of classical billiard - the Andreev billiard - is investigated using the tangent map technique. Andreev billiards consist of a normal region surrounded by a superconducting region. In contrast with previously studied billiards, Andreev billiards are integrable in zero magnetic field, {\it regardless of their shape}. A magnetic field renders chaoti

Xinsheng Ling, Chao Tang, S. Bhattacharya, Paul M. Chaikin

Motivated by the recent observations of the peak effect in high-$T_c$ YBCO superconductors, we reexamine the origin of this unusual phenomenon. We show that the mechanism based on the $k$-dependence (nonlocality) of the vortex-lattice tilt modulus $C_{44}({\bf k})$ cannot account for the essential feature of the peak effect. We propose a scenario in which th

M. R. Zirnbauer, F. D. M. Haldane

At coupling strengths lambda = 1/2, 1, or 2, the Calogero-Sutherland model (CSM) is related to Brownian motion in a Wigner-Dyson random matrix ensemble with orthogonal, unitary, or symplectic symmetry. Using this relation in conjunction with superanalytic techniques developed in mesoscopic conductor physics, we derive an exact integral representation for the

P. Bernier, I. Luk'yanchuk, Z. Belahmer, M. Ribet

Solid state high resolution $^{13}C$ NMR has been used to investigate the physical properties of pristine $C_{60}$ after intercalation with molecular oxygen. By studying the dipolar and hyperfine interactions between Curie type paramagnetic oxygen molecules and $^{13}C$ nuclei we have shown that neither chemical bonding nor charge transfer results from the i

A Martin, CJ Lambert

By solving the Bogoliubov - de Gennes equation self-consistently in the presence of a non-equilibrium quasi-particle distribution, we compute the current-voltage characteristic of a phase coherent superconducting island with a tunnel barrier at one end. The results show significant structure, arising from the competition between scattering processes at the b

Klaus Frahm

The autocorrelation function $C_{φ,\eps}(Δφ,\,Δ\eps)=$ $\langle δg(φ,\,\eps)\, δg(φ+Δφ,\,\eps+Δ\eps)\rangle$ ($φ$ and $\eps$ are rescaled magnetic flux and energy) for the magnetoconductance of a ballistic chaotic quantum dot is calculated in the framework of the supersymmetric non-linear $σ$-model. The Hamiltonian of the quantum dot is modelled by a Gaussia

Gerald Bedürftig, Holger Frahm

A new supersymmetric model for electrons with generalized hopping terms and Hubbard interaction on a one-dimensional lattice is solved by means of the Bethe Ansatz. We investigate the phase diagram of this model by studying the ground state and excitations of the model as a function of the interaction parameter, electronic density and magnetization. Using ar

Masahito Takahashi, Yasuhiro Hatsugai, Mahito Kohmoto

We consider conductivities of two-dimensional lattice electrons in a magnetic field. We focus on systems where the flux per plaquette $ϕ$ is irrational (incommensurate flux). To realize the system with the incommensurate flux, we consider a series of systems with commensurate fluxes which converge to the irrational value. We have calculated a real part of th

A. D. Speliotopoulos

A quantum mechanical description of vortices in two dimensional superfluid $^4$He flims is presented. Single vortex creation and annihilation operators are defined and wavefunctions for these states are explicitly constructed. A hamitonian for these states is then proposed.

T. Mark Ellison

This paper shows that default-based phonologies have the potential to capture morphophonological generalisations which cannot be captured by non-defaul theories. In achieving this result, I offer a characterisation of Underspecification Theory and Optimality Theory in terms of their methods for ordering defaults. The result means that machine learning techni

T. Mark Ellison

Optimality Theory is a constraint-based theory of phonology which allows constraints to be violated. Consequently, implementing the theory presents problems for declarative constraint-based processing frameworks. On the basis of two regularity assumptions, that candidate sets are regular and that constraints can be modelled by transducers, this paper present

Robert Dale, Ehud Reiter

We examine the problem of generating definite noun phrases that are appropriate referring expressions; i.e, noun phrases that (1) successfully identify the intended referent to the hearer whilst (2) not conveying to her any false conversational implicatures (Grice, 1975). We review several possible computational interpretations of the conversational implicat

Daniel Marcu

Since Austin introduced the term ``infelicity'', the linguistic literature has been flooded with its use, but no formal or computational explanation has been given for it. This thesis provides one for those infelicities that occur when a pragmatic inference is cancelled. Our contribution assumes the existence of a finer grained taxonomy with respect

Daniel Marcu, Graeme Hirst

We rely on the strength of linguistic and philosophical perspectives in constructing a framework that offers a unified explanation for presuppositions and existential commitment. We use a rich ontology and a set of methodological principles that embed the essence of Meinong's philosophy and Grice's conversational principles into a stratified logic, u

Daniel Marcu, Graeme Hirst

Drawing appropriate defeasible inferences has been proven to be one of the most pervasive puzzles of natural language processing and a recurrent problem in pragmatics. This paper provides a theoretical framework, called ``stratified logic'', that can accommodate defeasible pragmatic inferences. The framework yields an algorithm that computes the conv

Chris Mihos, Ian Walker, Lars Hernquist, Claudia Mendes de Oliviera

Using numerical simulation, we study the response of a disk galaxy to a merger involving a low-mass satellite companion. During a prograde satellite accretion, the disk galaxy forms a strong bar in response to the perturbation of the companion. After the accretion event is over, the bar buckles vertically due to a bending instability, sending disk material w

Th. Boller, W. N. Brandt, H. Fink

We report on AGN with extremely soft X-ray spectra observed with ROSAT. From their optical emission lines these objects are classified as narrow-line Seyfert 1 galaxies (NLS1), almost all with extremely large Fe II/H-beta ratios and relatively narrow optical lines of hydrogen. Our results are based on a systematic study of 46 NLS1. We find that NLS1 have gen

Andrew Gould

By monitoring $10^6$ quasars one could search for lensing by stars and Massive Compact Halo Objects (Machos) out to redshifts $z\sim 4$. If Machos have a present cosmological density $Ω_{L,0}=1\%$, then the expected event rate is $Γ\sim 200\,\yr^{-1}$. The expected event rate for known stars in galaxies is $Γ\sim 20\,\yr^{-1}$ assuming that their present cos

Annie C. Robin, Misha Haywood, Crézé, Devendra K. Ojha

Accurate characterization of thick disc properties from recent kinematic and photometric surveys provides converging evidences that this intermediate population is a sequel of the violent heating of early disc populations by a merging satellite galaxy. The thick disc population is revisited under the light of new data in a number of galactic sample fields. V

M. J. Iqbal, Xuemin Jin, Derek B. Leinweber

It is shown, in a model independent way, that the large difference in rho and omega widths gives rise to a new source of momentum dependence for the rho-omega mixing matrix element. The q^2 dependence arising due to the meson widths leads to a significant alteration of the result obtained in the zero-width approximation usually discussed in the literature. T

J. N. Goldberg, C. Soteriou

We use the canonical formalism developed together with David Robinson to st= udy the Einstein equations on a null surface. Coordinate and gauge conditions = are introduced to fix the triad and the coordinates on the null surface. Toget= her with the previously found constraints, these form a sufficient number of second class constraints so that the phase spa

R. D. Peccei

After a brief history of the insights gained from Kaon physics, the potential of Kaon decays for probing lepton number violation is discussed. Present tests of CTP and of Quantum Mechanics in the neutral Kaon sector are then reviewed and the potential of the Frascati $Φ$ factory for doing incisive tests in this area is emphasized. The rest of this overview f

Stefan Lenz, Hubertus Mall

Monte-Carlo methods for zero energy quantum scattering are developed. Starting from path integral representations for scattering observables, we present results of numerical calculations for potential scattering and scattering off a schematic $^4 \rm He $ nucleus. The convergence properties of Monte-Carlo algorithms for scattering systems are analyzed using

Mikel Susperregi, Thomas Buchert

A first- and second-order relation between cosmic density and peculiar-velocity fields is presented. The calculation is purely Lagrangian and it is derived using the second-order solutions of the Lagrange-Newton system obtained by Buchert & Ehlers. The procedure is applied to two particular solutions given generic initial conditions. In this approach, the co

Chopin Soo

A positive semi-definite Euclidean action for arbitrary four-topologies can be constructed by adding appropriate Yang-Mills and topological terms to the Samuel-Jacobson-Smolin action of gravity with (anti)self-dual variables. Moreover, on-shell, the (anti)self-dual sector of the new theory corresponds precisely to all Einstein manifolds in four dimensions. T

P. Gaspard, J. R. Dorfman, .

The foundations of the chaotic scattering theory for transport and reaction-rate coefficients for classical many-body systems are considered here in some detail. The thermodynamic formalism of Sinai, Bowen, and Ruelle is employed to obtain an expression for the escape-rate for a phase space trajectory to leave a finite open region of phase space for the firs

N. Ciccoli

Quantum planes and a new quantum cylinder are obtained as quantization of Poisson homogeneous spaces of two different Poisson structures on classical Euclidean group E(2).

Haisheng Li

We introduce the notion of ``local system of $\Bbb{Z}_{T}$-twisted vertex operators'' on a $\Bbb{Z}_{2}$-graded vector space $M$, generalizing the notion of local system of vertex operators [Li]. First, we prove that any local system of $\Bbb{Z}_{T}$-twisted vertex operators on $M$ has a vertex superalgebra structure with an automorphism $σ$ of order

J. Arrington, P. Anthony, R. G. Arnold, E. J. Beise

The inclusive A(e,e') cross section for $x \simeq 1$ was measured on $^2$H, C, Fe, and Au for momentum transfers $Q^2$ from 1-7 (GeV/c)$^2$. The scaling behavior of the data was examined in the region of transition from y-scaling to x-scaling. Throughout this transitional region, the data exhibit $ξ$-scaling, reminiscent of the Bloom-Gilman duality seen

Z. Jiang, R. A. Brown

The diffusion path and diffusivity of oxygen in crystalline silicon are computed using an empirical interatomic potential which was recently developed for modelling the interactions between oxygen and silicon atoms. The diffusion path is determined by constrained energy minimization, and the diffusivity is computed using jump rate theory. The calculated diff

Valeri V. Dvoeglazov

The problems connected with a choice of the spinorial basis in the $(j,0)\oplus (0,j)$ representation space are discussed. It is shown to have profound significance in relativistic quantum theory. From the methodological viewpoint this fact is related with the important dynamical role played by space-time symmetries for all kind of interactions.

Hidenori Sonoda

This is the first of three papers on the short-distance properties of the energy-momentum tensor in field theory. We study the energy-momentum tensor for renormalized field theory in curved space. We postulate an exact Ward identity of the energy-momentum tensor. By studying the consistency of the Ward identity with the renormalization group and diffeomorphi

Silvio J. Rabello, Patricio Gaete

In this paper we use the Batalin-Fradkin-Vilkovisky formalism to study a recently proposed nonlocal symmetry of QED. In the BFV extended phase space we show that this symmetry stems from a canonical transformation in the ghost sector.

Mikhail V. Saveliev

In the present paper we obtain some integrable generalisations of the continuous Toda system generated by a flat connection form taking values in higher grading subspaces of the algebra of the area--preserving diffeomorphism of the torus $T^2$, and construct their general solutions. The grading condition which we use here, imposed on the connection, can be r

R. Banerjee

We show in three dimensions, using functional integral techniques, the equivalence between the partition functions of the massive Thirring model and a gauge theory with two gauge fields, to all orders in the inverse fermion mass. Detailed bosonisation identities, also valid to all orders in the inverse mass, are derived. Specialisation to the lowest (and nex

P. Mayr, S. Stieberger

We derive the moduli dependence of the one--loop gauge couplings for non--vanishing gauge background fields in a four--dimensional heterotic (0,2) string compactification. Remarkably, these functions turn out to have a representation as modular functions on an auxiliary Riemann surface on appropriate truncations of the full moduli space. In particular, a cer

Requardt M

Starting from an extension of the Poisson bracket structure and Kubo-Martin-Schwinger-property of classical statistical mechanics of continuous systems to spin systems, defined on a lattice, we derive a series of, as we think, new and interesting bounds on correlation functions for general lattice systems. Our method is expected to yield also useful results

J. L. Petersen, J. Rasmussen, M. Yu

We show how to deal with screening charges involving fractional powers of free fields. This enables us to use the free field Wakimoto construction to obtain complete expressions for integral representations of conformal blocks for N-point functions on the sphere, also in the case of non-integrable representations, in particular for admissible representations

Yoshihisa Kitazawa, Masao Ninomiya

We study the renormalization of the Ricci curvature as an example of generally covariant operators in quantum gravity near two dimensions. We find that it scales with a definite scaling dimension at short distance. The Ricci curvature singularity at the big bang can be viewed as such a scaling phenomenon. The problem of the spacetime singularity may be resol

Kunio Funahashi, Taro Kashiwa, Shuji Nima, Seiji Sakoda

Path integral for the $SU(2)$ spin system is reconsidered. We show that the Nielsen-Rohrlich(NR) formula is equivalent to the spin coherent state expression so that the phase space in the NR formalism is not topologically nontrivial. We also perform the WKB approximation in the NR formula and find that it gives the exact result.

A. Galperin, E. Sokatchev

Witten's linear sigma model for ADHM instantons possesses a natural $(0,4)$ supersymmetry. We study generalizations of the infrared limit of the model that are invariant under $(4,4)$ supersymmetry. In the case of four space-time dimensions a background with a conformally flat metric and torsion is required. The geometry is specified by a single real sca

C. G. S. Costa, F. Halzen, C. Salles

We show that a simple scaling model of very forward particle production, consistent with accelerator and air shower data, can describe all features of the very high-energy interactions recorded with emulsion chambers. This is somewhat surprising after numerous claims that the same data implied large scaling violations or new dynamics. Interestingly, we canno

Mihoko M. Nojiri

Study of the production and decay of scalar tau lepton ($\st$) at future $\epem$ colliders helps to determine the value of $\tanβ$ through the measurement of the polarization of $τ$ lepton that arises from $\st$ decay. Key maps of the parameter space of MSSM are presented. (talk presented at the fifth workshop on Japan Linear Collider(JLC) at Kawatabi, Feb 1

S. Yu. Khlebnikov, R. G. Schnathorst

We consider chiral $U(N)\times U(N)$ models with fermions in the limit of infinitely large local bare Yukawa coupling. When the scalar field is subject to non-linear constraint, phase transitions in these models are seen to be identical to those in the corresponding purely bosonic ones. Relaxing the non-linear constraint, we compute the seventh-order strong-

James E. Hill

The Liquid Scintillator Neutrino Detector (LSND) at the Los Alamos Meson Physics Facility sets bounds on neutrino oscillations in the appearance channel nu_mu_bar --> nu_e_bar by searching for the signature of the reaction nu_e_bar p --> e^+ n: an e$^+$ followed by a 2.2MeV gamma ray from neutron capture. Five e^{+/-} -- gamma coincidences are observed in ti

Daniel J. Loranz, William A. Hiscock, Paul R. Anderson

The expectation value of the stress-energy tensor $\langleT_{μν}\rangle$ of a free conformally invariant scalar field is computed in a general static two-dimensional black hole spacetime when the field is in either a zero temperature vacuum state or a thermal state at a nonzero temperature. It is found that for every static two-dimensional black hole the str

G. M. Shore

A number of general issues relating to superluminal photon propagation in gravitational fields are explored. The possibility of superluminal, yet causal, photon propagation arises because of Equivalence Principle violating interactions induced by vacuum polarisation in QED in curved spacetime. Two general theorems are presented: first, a polarisation sum rul

Franz Embacher

Using the concept of real tunneling configurations (classical signature change) and nucleation energy, we explore the consequences of an alternative minimization procedure for the Euclidean action in multiple-dimensional quantum cosmology. In both standard Hartle-Hawking type as well as Coleman type wormhole-based approaches, it is suggested that the action

M. C. W. van Rossum

In my thesis I study mesoscopic corrections on diffuse transport. I first describe the diffuse transport of light, using the scalar approximation and the radiative transfer approach. Next, I focus on the correlations in transmission, I discuss the so called C_1, C_2, C_3 decomposition and calculate each term in detail. Finally, I discuss the full distributio

K. A. Matveev, L. I. Glazman, H. U. Baranger

We present a theory of Coulomb blockade oscillations in tunneling through a pair of quantum dots connected by a tunable tunneling junction. The positions and amplitudes of peaks in the linear conductance are directly related, respectively, to the ground state energy and to the dynamics of charge fluctuations. We study analytically both strong and weak interd

Klaus Frahm, Jean-Louis Pichard

Using the Fokker-Planck equation describing the evolution of the transmission eigenvalues for Dyson's Brownian motion ensemble, we calculate the magnetoconductance of a ballistic chaotic dot in in the crossover regime from the orthogonal to the unitary symmetry. The correlation functions of the transmission eigenvalues are expressed in terms of quaternio

Klaus Frahm, Jean-Louis Pichard

The parametric correlations of the transmission eigenvalues $T_i$ of a $N$-channel quantum scatterer are calculated assuming two different Brownian motion ensembles. The first one is the original ensemble introduced by Dyson and assumes an isotropic diffusion for the $S$-matrix. The second Brownian motion ensemble assumes for the transfer matrix $M$ an isotr

V. I. Inozemtsev

It is found that the Hamiltonian of S=1/2 isotropic Heisenberg chain with $N$ sites and elliptic non-nearest-neighbor exchange is diagonalized in each sector of the Hilbert space with magnetization $N/2-M$, $1<M\leq[N/2]$, by means of double quasiperiodic meromorphic solutions to the $M$-particle quantum Calogero-Moser problem on a line. The spectrum and hig

Mark Johnson

This paper discusses the relationship between memoized top-down recognizers and chart parsers. It presents a version of memoization suitable for continuation-passing style programs. When applied to a simple formalization of a top-down recognizer it yields a terminating parser.

J. Bricmont, A. Kupiainen

We develop a resummed high-temperature expansion for lattice spin systems with long range interactions, in models where the free energy is not, in general, analytic. We establish uniqueness of the Gibbs state and exponential decay of the correlation functions. Then, we apply this expansion to the Perron-Frobenius operator of weakly coupled map lattices.