December 1993 arXiv papers — page 4

L. Burakovsky, L. P. Horwitz

A manifestly covariant relativistic statistical mechanics of the system of $N$ indistinguishable events with motion in space-time parametrized by an invariant ``historical time'' $τ$ is considered. The relativistic mass distribution for such a system is obtained from the equilibrium solution of the generalized relativistic Boltzmann equation by integ

JosÉ W. F. Valle

Present limits on neutrino masses are briefly reviewed, along with cosmological and astrophysical hints from dark matter, solar and atmospheric neutrino observations that suggest neutrino masses. These would imply many possible new phenomena such as neutrinoless $\beta\beta$ decay, lepton flavour violating processes such as neutrino oscillations, $\mu \ra e

L. Burakovsky, L. P. Horwitz

The relativistic Maxwell-Boltzmann distribution for the system of $N$ events with motion in space-time parametrized by an invariant ``historical time'' $τ$ is considered without the simplifying approximation $m^2\cong M^2$, where $M$ is a given intrinsic property of the events. The relativistic mass distribution is obtained and the average values of

B. Mele

Recent LEP results on electroweak precision measurements are reviewed. Line-shape and asymmetries analysis on the Z peak is described. Then, the consistency of the Standard Model predictions with experimental data and consequent limits on the top mass are discussed. Finally, the possibility of extracting information and constrains on new theoretical models f

M. Bilenky, K. Kolodziej, M. Kuroda, D. Schildknecht

The recent precision electroweak data on $Γ^l, \bar s^2_W$ and $M_W/M_Z$ are compared with the tree-level and the dominant-fermion-loop as well as the full one-loop standard-model predictions. While the tree-level predictions are ruled out, the dominant-fermion-loop predictions, defined by using $α(M^2_Z)\cong 1/128.9$ in the tree-level formulae, as well as

I. Vilja

The baryogenesis by decays of the right--handed neutrinos in the Majoron model is studied. We show that compared to the observational value it is possible to produce large enough baryon asymmetry in the Majoron model or, at least, contribute strongly to it. It requires that the mass of the lightest right--handed neutrino is about (or above) 1 TeV and the sel

Haim Goldberg

I present a model for inflation based on the gaugino-dilaton dynamics of supersymmetry breaking. The inflaton is the dimension--1 scalar field $ϕ$ related to the gaugino condensate via $λ^Tλ=ϕ^3.$ Recent work in this area is used to obtain two significant results: (1) Scalar density fluctuations at second horizon crossing are generated on scale $λ$ with ampl

Klaus Geiger, Berndt Mueller

We derive a generalized form of Altarelli-Parisi equations to decribe the time evolution of parton distributions in a nuclear medium. In the framework of the leading logarithmic approximation, we obtain a set of coupled integro- differential equations for the parton distribution functions and equations for the virtuality (``age'') distribution of par

H. Markum, K. Rabitsch, W. Sakuler

The interaction of spatially extended heavy hadrons is investigated in the framework of lattice QCD with dynamical quarks. In addition to the baryon-baryon potential results for the baryon-antibaryon and for the meson-meson system are presented. It is shown that the expected dipole forces have a very short range and that sea quarks play a minor important rol

K. Rabitsch, H. Markum, W. Sakuler

The interaction of spatially extended heavy baryons is investigated in the framework of lattice QCD with dynamical quarks. It is shown that the expected dipole forces have a very short range and that the baryon-antibaryon interaction is more attractive than the baryon-baryon interaction. Sea quarks play a minor important role.

Janna Levin, Katherine Freese

The evolution of a universe with Brans-Dicke gravity and nonzero curvature is investigated here. We present the equations of motion and their solutions during the radiation dominated era. In a Friedman-Robertson-Walker cosmology we show explicitly that the three possible values of curvature $κ=+1,0,-1$ divide the evolution of the Brans-Dicke universe into dy

Michael P. Ryan

The coincidence of quantum cosmology solutions generated by solving a Euclidean version of the Hamilton-Jacobi equation for gravity and by using the complex canonical transformation of the Ashtekar variables is discussed. An examination of similar solutions for the free electromagnetic field shows that this coincidence is an artifact of the homogeneity of th

Arvind Borde, Alexander Vilenkin

It is shown that a physically reasonable spacetime that is eternally inflating to the future must possess an initial singularity.

William M. Pezzaglia

Attention is given to the interface of mathematics and physics, specifically noting that fundamental principles limit the usefulness of otherwise perfectly good mathematical general integral solutions. A new set of multivector solutions to the meta-monogenic (massive) Dirac equation is constructed which form a Hilbert space. A new integral solution is propos

Jun Hu, A. H. MacDonald

We report on a high temperature perturbation expansion study of the superfluid-density spatial correlation function of a Ginzburg-Landau-model superconducting film in a magnetic field. We have derived a closed form which expresses the contribution to the correlation function from each graph of the perturbation theory in terms of the number of Euler paths aro

Y. M. Vilk, Liang Chen, A. -M. S. Tremblay

A self-consistent theory of both spin and charge fluctuations in the Hubbard model is presented. It is in quantitative agreement with Monte Carlo data at least up to intermediate coupling $(U\sim 8t)$. It includes both short-wavelength quantum renormalization effects, and long-wavelength thermal fluctuations which can destroy long-range order in two dimensio

J. A. Støvneng, P. Lipavský

We study tunneling in semiconductor heterostructures where the constituent materials can have a direct or indirect bandgap. In order to have a good description of the lowest conduction band, we have used the nearest-- neighbour $sp^3s^*$ tight--binding model put forward by P. Vogl {\em et al.}. A recursive Green--function method yields transmission coefficie

Jens Jensen

The two main characteristics of the holmium ions in HoF_3 are that their local electronic properties are dominated by two singlet states lying well below the remaining 4f-levels, and that the classical dipole-coupling is an order of magnitude larger than any other two-ion interactions between the Ho-moments. This combination makes the system particularly sui

Yong-Cong Chen

We present a Schwinger-boson approach for the RVB state of the spin-1/2 Heisenberg antiferromagnet on a triangular lattice. It is shown that Gutzwiller projection of the mean-field state that includes both antiferromagnetic and ferromagnetic decouplings leads to optimizing the RVB pair amplitudes within a self-consistent approximation. The resulting state yi

A. Gangui, F. Lucchin, S. Matarrese, S. Mollerach

We analyze the temperature three--point correlation function and the skewness of the Cosmic Microwave Background (CMB), providing general relations in terms of multipole coefficients. We then focus on applications to large angular scale anisotropies, such as those measured by the {\em COBE} DMR, calculating the contribution to these quantities from primordia

Z. Arzoumanian, A. S. Fruchter, J. H. Taylor

We have conducted timing observations of the eclipsing millisecond binary pulsar PSR~B1957+20, extending the span of data on this pulsar to more than five years. During this time the orbital period of the system has varied by roughly $ΔP_b/P_b = 1.6 \times 10^{-7}$, changing quadratically with time and displaying an orbital period second derivative $\ddot P_

A. Lawrence, E. Martinec

We develop the quantization of a macroscopic string which extends radially from a Schwarzschild black hole. The Hawking process excites a thermal bath of string modes that causes the black hole to lose mass. The resulting typical string configuration is a random walk in the angular coordinates. We show that the energy flux in string excitations is approximat

F. J. Herranz, M. de Montigny, M. A. del Olmo, M. Santander

We study $\Bbb Z_2^{\otimes N}$ graded contractions of the real compact simple Lie algebra $so(N+1)$, and we identify within them the Cayley-Klein algebras as a naturally distinguished subset.

Pavel Etingof, Boris Khesin

Conjecture 9B from the previous version of the paper stating that any holomorphic vector bundle on an elliptic curve can be realized by a scalar differential equation has now been proved by the authors. The proof is included in the new version.

Chr. V. Christov, K. Goeke, P. Pobilitsa, V. Petrov

The $1/N_c$ rotational corrections to the axial vector constant and the isovector magnetic moment of the nucleon are studied in the Nambu -- Jona-Lasinio model. We follow a semiclassical quantization procedure in terms of path integrals in which we can include perturbatively corrections in powers of angular velocity $Ω\sim \frac 1{N_c}$. We find non-zero $1/

A. Jevicki, J. Rodrigues

We consider the loop space representation of multi-matrix models. Explaining the origin of a time variable through stochastic quantization we make contact with recent proposals of Ishibashi and Kawai. We demonstrate how collective field theory with its loop space interactions generates a field theory of non-critical strings.

M. Bonini, M. D'Attanasio, G. Marchesini

We study the formulation of the Wilson renormalization group (RG) method for a non-Abelian gauge theory. We analyze the simple case of $SU(2)$ and show that the local gauge symmetry can be implemented by suitable boundary conditions for the RG flow. Namely we require that the relevant couplings present in the physical effective action, \ie the coefficients o

Taichiro Kugo, Mark G. Mitchard, Yuhsuke Yoshida

We develop the improved ladder approximation to QCD in order to apply it to the heavy quark mesons. The resulting Bethe-Salpeter equation is expanded in powers of the inverse heavy quark mass 1/M, and is shown to be consistent with the heavy quark spin symmetry. We calculate numerically the universal leading order BS amplitude for heavy pseudoscalar and vect

Claude Laflamme

We analyze several ``strong meager'' properties for filters on the natural numbers between the classical Baire property and a filter being $F_σ$. Two such properties have been studied by Talagrand and a few more combinatorial ones are investigated. In particular, we define the notion of a P$^+$-filter, a generalization of the traditional concept of P

A. Stern, I. Yakushin

We perform a deformation quantization of the classical isotropic rigid rotator. The resulting quantum system is not invariant under the usual $SU(2)\times SU(2)$ chiral symmetry, but instead $SU_{q^{-1}}(2) \times SU_q(2)$.

Olaf Lechtenfeld

I investigate non-perturbative aspects of zero-dimensional matrix models. Subtleties in the large-$N$ limit of the semiclassical picture are pointed out. The tunneling of eigenvalues is seen to correspond to a chaotic sequence of recursion coefficients determining the orthogonal polynomials.

D. Bailin, A. Love, W. A. Sabra, S. Thomas

Target space modular symmetries relevant to string loop threshold corrections are studied for $Z_N$ orbifold compactified string theories containing Wilson line background fields.

Costas Efthimiou, Andre LeClair

Using a duality between the space of particles and the space of fields, we show how one can compute form factors directly in the space of fields. This introduces the notion of vertex operators, and form factors are vacuum expectation values of such vertex operators in the space of fields. The vertex operators can be constructed explicitly in radial quantizat

A. P. Zubarev

$D=2$ free string in linear dilaton background is considered in so called target space/world-sheet light cone gauge $ X^{+}=0,~g_{++}=0,~g_{+-}=1$. After gauge fixing the theory has the residual Virasoro and $U(1)$ current symmetries. The physical spectrum related to $SL_2$ invariant vacuum is found to be trivial. We find that the theory has a nontrivial spe

Alexander Varchenko

The quasiclassical asymptotics of the Knizhnik-Zamolodchikov equation with values in the tensor product of sl(2)- representations are considered. The first term of asymptotics is an eigenvector of a system of commuting operators. We show that the norm of this vector with respect to the Shapovalov form is equal to the determinant of the matrix of second deriv

W. Siegel

We clarify the nature of the graviton as a bound state in open-string field theory: The flat metric in the action appears as the vacuum value of an OPEN string field. The bound state appears as a composite field in the FREE field theory.

Boguslaw Broda

A new, formal, non-combinatorial approach to invariants of three-dimensional manifolds of Reshetikhin, Turaev and Witten in the framework of non-perturbative topological quantum Chern-Simons theory, corresponding to an arbitrary compact simple Lie group, is presented. A direct implementation of surgery instructions in the context of quantum field theory is p

H. J. de Vega, A. L. Larsen, N. Sánchez

The exact general evolution of circular strings in $2+1$ dimensional de Sitter spacetime is described closely and completely in terms of elliptic functions. The evolution depends on a constant parameter $b$, related to the string energy, and falls into three classes depending on whether $b<1/4$ (oscillatory motion), $b=1/4$ (degenerated, hyperbolic motion) o

Johannes Huebschmann

In earlier work we have shown that the moduli space $N$ of flat connections for the (trivial) $\roman{SU(2)}$-bundle on a closed surface of genus $\ell \geq 2$ inherits a structure of stratified symplectic space with two connected strata $N_Z$ and $N_{(T)}$ and $2^{2\ell}$ isolated points. In this paper we show that, close to each point of $N_{(T)}$, the spa

Johannes Huebschmann

Symplectic and Poisson structures of certain moduli spaces/Huebschmann,J./ Abstract: Let $π$ be the fundamental group of a closed surface and $G$ a Lie group with a biinvariant metric, not necessarily positive definite. It is shown that a certain construction due to A. Weinstein relying on techniques from equivariant cohomology may be refined so as to yield

R. Schimmrigk

Recent work on the relation between a special class of Kähler manifolds with positive first Chern class and critical N$=$2 string vacua with c$=$9 is reviewed and extended. (Based on a talk presented at the International Workshop on Supersymmetry and Unification of Fundamental Interactions (SUSY 93), Boston, MA, March 1993)

A. V. Smilga

The known calculations of the fermion condensate $<\barψψ>$ and the correlator $<\barψψ(x) ~\barψψ(0)>$ have been interpreted in terms of {\em localized} instanton solutions minimizing the {\em effective} action. Their size is of order of massive photon Compton wavelength $μ^{-1}$. At high temperature, these instantons become quasistatic and present the 2-di

Patrick PETER

It is shown that in models including the standard electroweak theory and for some particular values of the underlying parameters, electric currents can be spontaneously generated in cosmic strings, without the need of any external field (e.g., electric or magnetic) as is required in most models. This mechanism is then shown to break spontaneously the Lorentz

O. J. P. Eboli, M. C. Gonzalez-Garcia, A. Lopez-Fernandez, S. F. Novaes

Higgs bosons can have a substantial ``invisible&#39;&#39; branching ratio in many extensions of the Standard Model, such as models where the Higgs bosons decay predominantly into light or massless weakly interacting Goldstone bosons. In this work, we examine the production mechanisms and backgrounds for invisibly decaying Higgs bosons at the Next Linear $e^+

M. C. Gonzalez-Garcia, F. Halzen, R. A. Vázquez

We demonstrate that the dispersive computation of the threshold enhancements to heavy quark vacuum polarizations is unstable. Because of the slow convergence of the dispersion relations the result critically depends on the intermediate energy region where the non-relativistic approximation, intrinsic to threshold calculations, is invalid. We discuss other am

Gregory Mahlon

We apply the solution to the recursion relation for the double-off-shell quark current to the problem of computing one loop amplitudes with an arbitrary number of gluons. We are able to compute amplitudes for photon-gluon scattering, electron-positron annihilation to gluons, and gluon-gluon scattering via a quark loop in the case of like-helicity gluons. In

Ken-ichiro Ogawa, Sachiko Takeuchi, Makoto Oka

A phenomenological model for the hyperon-nucleon interactions is constructed by using the quark cluster model approach to the short-distance baryon-baryon interactions. The model contains the SU(3) symmetric meson exchange interaction at large distances and the quark-exchange short-distance interaction. The main feature of the model is that strong channel de

G. Jikia, A. Tkabladze

$γγ\toγZ$ scattering at the Photon Linear Collider is considered. Explicit formulas for helicity amplitudes due to $W$ boson loops are presented. It is shown that the $Zγ$ pair production will be easily observable at PLC and separation of the $W$ loop contribution will be possible at $e^+e^-$ c.m. energy of 300~GeV or higher.

M. Goeckeler, R. Horsley, P. E. L. Rakow, G. Schierholz

We give a 1993 update of non-compact lattice QED, in particular the chiral condensate, finite size effects and meson mass ratios. We compare descriptions of the phase transition. Our previous conclusions remain valid.

M. Caselle, R. Fiore, F. Gliozzi, P. Guaita

The behaviour of the space-like string tension in the high temperature phase is studied. Data obtained in the $Z_2$ gauge model in (2+1) dimensions are compared with predictions of a simple model of a fluctuating flux tube with finite thickness. It is shown that in the high temperature phase contributions coming from the fluctuations of the flux tube vanish.

W. Beirl, H. Markum, J. Riedler

Quantum gravity is studied in the path integral formulation applying the Regge calculus. Restricting the quadratic link lengths of the originally triangular lattice the path integral can be transformed to the partition function of a spin system with higher couplings on a Kagome lattice. Various measures acting as external field are considered. Extensions to

Wolfgang Beirl, Harald Markum, Juergen Riedler

We investigate quantum gravity in the path integral formulation using the Regge calculus. Restricting the quadratic link lengths of the originally triangular lattice the path integral can be transformed to the partition function of a spin system with higher couplings on a Kagome lattice. Various measures acting as external field were considered. Extensions t

W. Beirl, H. Markum, J. Riedler

We investigate the interaction mechanism of pure quantum gravity in Regge discretization. We compute volume-volume and link-link correlation functions. In a preliminary analysis the forces turn out to be of Yukawa type, at least on our finite lattice being away from the continuum limit.

Roland Fehrenbacher

The optical conductivity of the CuO$_3$-chains, a subsystem of the 1-2-3 materials, is dominated by a broad peak in the mid-infrared ($ω\approx 0.2$eV), and a slowly falling high-frequency tail. The 1D $t$-$J$-model is proposed as the relevant low-energy Hamiltonian describing the intrinsic electronic structure of the CuO$_3$-chains. However, due to charge-s

P. Chandra, P. Coleman, L. B. Ioffe

We introduce an $xy$ generalization of the frustrated Ising model on a triangular lattice. The presence of continuous degrees of freedom stabilizes a {\em finite-temperature} spin state with {\em power-law} discrete spin correlations and an extensive zero-point entropy. In this phase, the unquenched degrees of freedom can be described by a fluctuating surfac

L. B. Ioffe, A. I. Larkin, A. J. Millis, B. L. Altshuler

We formulate and solve a model of two planes of antiferromagnetically correlated electrons coupled together by a weak antiferromagnetic interaction of strength $λ$. We show that in-plane antiferromagnetic correlations dramatically enhance the pairing effect of the interplane interaction. For the case where the in-plane correlation length $κ^{-1} \sim T^{-1/2

S. L. Pepke, J. M. Carlson

We study the predictability of large events in self-organizing systems. We focus on a set of models which have been studied as analogs of earthquake faults and fault systems, and apply methods based on techniques which are of current interest in seismology. In all cases we find detectable correlations between precursory smaller events and the large events we

David Y. K. Ko, Flavio Seno

We present simulation results of deposition growth of surfaces in 2, 3 and 4 dimensions for ballistic deposition where overhangs are present, and for restricted solid on solid deposition where there are no overhangs. The values of the scaling exponents for the two models are found to be different, suggesting that they belong to different universality classes

Giuseppe Rossi

Minimum total energy calculations, which account for both electron--lattice and electron--electron interactions in conjugated polymers are performed for chains with up to eight carbon atoms. These calculations are motivated in part by recent experimental results on the spectroscopy of polyenes and conjugated polymers and shed light on the longstanding questi

Erwin Frey, David R. Nelson, Daniel S. Fisher

Interstitials and vacancies in the Abrikosov phase of clean Type II superconductors are line imperfections, which cannot extend across macroscopic equilibrated samples at low temperatures. We argue that the entropy associated with line wandering nevertheless can cause these defects to proliferate at a sharp transition which will exist if this occurs below th

Albert Diaz-Guilera

Several nonlinear stochastic differential equations have been proposed in connection with self-organized critical phenomena. Due to the threshold condition involved in its dynamic evolution an infinite number of nonlinearities arises in a hydrodynamic description. We study two models with different noise correlations which make all the nonlinear contribution

G. F. Smoot, L. Tenorio, A. J. Banday, A. Kogut

We use statistical and topological quantities to test the COBE-DMR first year sky maps against the hypothesis that the observed temperature fluctuations reflect Gaussian initial density perturbations with random phases. Recent papers discuss specific quantities as discriminators between Gaussian and non-Gaussian behavior, but the treatment of instrumental no

M. Tosi

The evolution of irregular galaxies is examined from two points of view: on the one hand, models of galactic chemical evolution have been computed and their predictions compared with the corresponding observational data on the element abundances, and on the other hand, the results of a new method to derive the star formation history in the last 1 Gyr in near

G. Vettolani, E. Zucca, A. Cappi, R. Merighi

We present the first results of a galaxy redshift survey, ESO Slice Project (ESP), we are accomplishing as an ESO Key--Project over about 40 square degrees in a region near the South Galactic Pole. The limiting magnitude is $b_J = 19.4$. Up to now $\sim 85\%$ of the observations has been completed and $\sim 65\%$ of the data has been reduced providing $\sim

K. R. Mecke, T. Buchert, H. Wagner

We propose a novel method for the description of spatial patterns formed by a coverage of point sets representing galaxy samples. This method is based on a complete family of morphological measures known as Minkowski functionals, which includes the topological Euler characteristic and geometric descriptors to specify the content, shape and connectivity of sp

Gerd Dethloff, Georg Schumacher, Pit-Mann Wong

The paper is a contribution to the conjecture of Kobayashi that the complement of a generic curve in the projective plane is hyperbolic, provided the degree is at least five. Previously the authors treated the cases of two quadrics and a line and three quadrics. The main results are Let C be the union of three curves in P_2 whose degrees are at least two, on

Gerd Dethloff, Georg Schumacher, Pit-Mann Wong

The paper is a contribution of the conjecture of Kobayashi that the complement of a generic plain curve of degree at least five is hyperbolic. The main result is that the complement of a generic configuration of three quadrics is hyperbolic and hyperbolically embedded as well as the complement of two quadrics and a line.

F. Acquistapace, F. Broglia, M. Pilar Velez

We give a constructive procedure to check basicness of open (or closed) semialgebraic sets in a compact, non singular, real algebraic surface $X$. It is rather clear that if a semialgebraic set $S$ can be separated from each connected component of $X\setminus(S\cup\frz S)$ (when $\frz S$ stands for the Zariski closure of $(\ol S\setminus{\rm Int}(S))\cap{\rm

D. A. Frail, W. M. Goss, V. I. Slysh

We present VLA observations in the hydroxyl line OH(1720 MHz) towards the supernova remnant W28. These high resolution images show a more extensive distribution of 1720 MHz emission than had previously been suspected from earlier single-dish observations. A total of 26 distinct maser spots were detected which lie on the edge of the radio continuum emission f

D. A. Lowe

This paper examines the causal structure of the commutator of two string fields, in free light-cone string field theory. By treating the commutator as a distribution on infinite dimensional loop space, it is shown that the commutator vanishes when $\int dß(δX(ß))^2 <0$. Of more direct physical interest is the commutator of finite mass fields, obtained by sme

S. Bertolini, M. Fabbrichesi, E. Gabrielli

The standard model contribution to $ε&#39;/ε$ of the magnetic- and electric-dipole penguin operators $Q_{11} = \frac{g_s}{16π^2} \, m_s \: \bar{s}\, σ_{μν} t^a G^{μν}_a (1-γ_5 )\, d $ and $Q_{12} = \frac{eQ_d}{16π^2}\, m_s \: \bar{s}\, σ_{μν} F^{μν} (1-γ_5 )\, d $ is discussed. While the electromagnetic penguin $Q_{12}$ seems to have a vanishingly small matr

Michael A. I. Flohr

The moduli space of all rational conformal quantum field theories with effective central charge c_eff = 1 is considered. Whereas the space of unitary theories essentially forms a manifold, the non unitary ones form a fractal which lies dense in the parameter plane. Moreover, the points of this set are shown to be in one-to-one correspondence with the element

B. Gall, P. Bonche, J. Dobaczewski, H. Flocard

A study of rotational properties of the ground superdeformed bands in \Hg{0}, \Hg{2}, \Hg{4}, and \Pb{4} is presented. We use the cranked Hartree-Fock-Bogoliubov method with the {\skm} parametrization of the Skyrme force in the particle-hole channel and a seniority interaction in the pairing channel. An approximate particle number projection is performed by

P. Mitra

Symmetries of multi-anyon wavefunctions are analysed with the help of a second quantized formulation. Analogues of Slater determinants are constructed. It is shown that the Pauli principle is not enforced.

D. Caenepeel, F. Gingras, M. Leblanc, D. G. C. McKeon

We present the scalar field effective potential for nonrelativistic self-interacting scalar and fermion fields coupled to an Abelian Chern-Simons gauge field. Fermions are non-minimally coupled to the gauge field via a Pauli interaction. Gauss&#39;s law linearly relates the magnetic field to the matter field densities; hence, we also include radiative effect

Adel Bilal

The present paper studies a completely integrable conformally invariant model in 1+1 dimensions that corresponds to string propagation on the two-dimensional black hole background (semi-ininite cigar). Besides the two space-time string fields there is a third (internal) field with a very specific Liouville-type interaction leading to the complete integrabili

V. V. Dodonov, V. I. Man&#39;ko, D. E. Nikonov

The multimode even and odd coherent states (multimode Schroedinger cat states) are constructed for polymode parametric oscillators of the electromagnetic field. The evolution of the photon distribution function is evaluated explicitly. The distribution function is expressed in terms of the multivariable Hermite polynomials, its means and dispersions are calc

Jose Gaite

The Landau potentials of $W_3$-algebra models are analyzed with algebraic-geometric methods. The number of ground states and the number of independent perturbations of every potential coincide and can be computed. This number agrees with the structure of ground states obtained in a previous paper, namely, as the phase structure of the IRF models of Jimbo et

Edward Witten

The article is devoted to a quantum field theory explanation of the relationship (noticed some years ago by Gepner) between the Verlinde algebra of the group $U(k)$ at level $N-k$ and the cohomology of the Grassmannian. The argument proceeds by starting with the two dimensional sigma model whose target space is the Grassmannian and integrating out some field

Pavel Etingof, Alexander Kirillov

In this paper we present a formula for Macdonald&#39;s polynomials for the root system A(n-1) which arises from the representation theory of quantum sl(n). This formula expresses Macdonald&#39;s polynomials via (weighted) traces of intertwining operators between certain modules over quantum sl(n). We also describe the commutative system of Macdonald&#39;s di

Christof Gattringer, Erhard Seiler

We study massless QED_2 with N flavors using path integrals. We identify the sector that is generated by the N^2 classically conserved vector currents. One of them (the U(1) current) creates a massive particle, while the others create massless ones. We show that the mass spectrum obeys a Witten-Veneziano type formula. Two theorems on n-point functions clarif

Pavel Etingof, Alexander Kirillov

A representation-theoretic approach to special functions was developed in the 40-s and 50-s in the works of I.M.Gelfand, M.A.Naimark, N.Ya.Vilenkin, and their collaborators. The essence of this approach is the fact that most classical special functions can be obtained as suitable specializations of matrix elements or characters of representations of groups.

Yukinori Yasui, Satoshi Takahashi

A topological field theory is used to study the cohomology of mapping space. The cohomology is identified with the BRST cohomology realizing the physical Hilbert space and the coboundary operator given by the calculations of tunneling between the perturbative vacua. Our method is illustrated by a simple example.

T. Brzezinski, A. J. Macfarlane

We define the $osp(1,2)$ Gaudin algebra and consider integrable models described by it. The models include the $osp(1,2)$ Gaudin magnet and the Dicke model related to it. Detailed discussion of the simplest cases of these models is presented. The effect of the presence of fermions on the separation of variables is indicated.

T. Fukui, N. Aizawa

An algebraic treatment of shape-invariant potentials is discussed. By introducing an operator which reparametrizes wavefunctions, the shape-invariance condition can be related to a generalized Heisenberg- Weyl algebra. It is shown that this makes it possible to define a coherent state associated with the shape-invariant potentials.

Alexander Givental, Bumsig Kim

We discuss relations of Vafa&#39;s quantum cohomology with Floer&#39;s homology theory, introduce equivariant quantum cohomology, formulate some conjectures about its general properties and, on the basis of these conjectures, compute quantum cohomology algebras of the flag manifolds. The answer turns out to coincide with the algebra of regular functions on a

A. Pich

The prospects for tau physics at future high-luminosity facilities are briefly discussed. Although important (and often complementary) contributions will be made from other machines, the unique experimental environment near threshold makes the Tau-Charm Factory the best experimental tool for $τ$ physics.

G. L. Kane, Chris Kolda, Leszek Roszkowski, James D. Wells

Taking seriously phenomenological indications for supersymmetry, we have made a detailed study of unified minimal SUSY, including effects at the few percent level in a consistent fashion. We report here a general analysis without choosing a particular unification gauge group. We find that the encouraging SUSY unification results of recent years do survive th

N. G. Deshpande, Xiao-Gang He

We study CP violation in a multi-Higgs doublet model based on a $S_3 \times Z_3$ horizontal symmetry where CKM phase is not the principal source of CP violation. We consider two mechanisms for CP violation in this model: a) CP violation due to complex Yukawa couplings; and b) CP violation due to scalar-pseudoscalar Higgs boson mixings. Both mechanisms can ex

A. Pich

The Tau-Charm Factory combines the optimum conditions to perform a high-precision investigation of the $τ$ and $ν_τ$ leptons, the $c$ quark, and light-quark, glueball and hybrid spectroscopy. An overview of the broad physics program that this facility will address is presented.

H. Weigel, R. Alkofer, H. Reinhardt

The recently developed method to investigate mesonic fluctuations off the chiral soliton in the Nambu--Jona--Lasinio model is applied to kaons in the S--wave channel. It is shown that for commonly accepted choices of parameters the presence of the soliton and the lack of confinement in this model provide an unphysical (valence) quark threshold which is lower

N. N. Nikolaev, B. G. Zakharov, V. R. Zoller

We derive a generalized Balitskii-Fadin-Kuraev-Lipatov equation, which applies directly to the perturbative QCD component of total cross section. With the gluon correlation radius $R_{c} \sim 0.4$f we reproduce the empirical rate of growth of the hadron-nucleon total cross sections. The simultaneous estimate of the triple-pomeron coupling also agrees with th

P. Elmfors, K. Enqvist, I. Vilja

We study non--equilibrium ensemble corrections to particle masses and the effective potential in the early universe, using a uniform momentum distribution as an example. The resulting thermalization temperature is computed assuming \sm degrees of freedom, and it is always found to be below $5\times 10^{14}$ GeV, implying that GUT phase transitions typically

B. Ehrnsperger, A. Schaefer, W. Greiner, L. Mankiewicz

We point out that the size of the photon single spin asymmetry in high--energy proton proton collisions with one transversely polarized proton can be related to $d^{(2)}$, the twist three contribution to the second moment of $g_2$. Both quantities should be measured in the near future. The first was analysed by Qiu and Sterman, the second was estimated by Ba

Yasumichi Aoki, Kazuyuki Kanaya

The surface tension $σ$ of the confined-deconfined interface is calculated in pure $SU(3)$ lattice gauge theory at finite temperatures employing the operator and integral methods on a lattice of a size $8^2\times N_z\times 2$ with $N_z=16$ and 40. Analyses of non-perturbative corrections in asymmetry response functions strongly indicate that the use of one-l

C. Alexandrou, S. Güsken, F. Jegerlehner, K. Schilling

We present a high statistics study of the leptonic decay constant $f_P$ of heavy pseudoscalar mesons using propagating heavy Wilson quarks within the quenched approximation, on lattices covering sizes from about 0.7~fm to 2~fm. Varying $β$ between 5.74 and 6.26 we observe a sizeable $a$ dependence of $f_P$ when one uses the quark field normalization that was

J. B. Kogut, J. -F. Lagae

We investigate the possibility of doing momentum space lattice simulations as an alternative to the conventional method. The procedure is introduced and tested for quenched QED2 and quenched QED3. Interesting physical applications to unquenched QED3 and quenched QED4 are also briefly discussed.

J. A. Rubio, R. P. Woodard

We resurrect a standard construction of analytical mechanics dating from the last century. The technique allows one to pass from any dynamical system whose first order evolution equations are known, and whose bracket algebra is not degenerate, to a system of canonical variables and a non-zero Hamiltonian that generates their evolution. We advocate using this

R. Montagne, A. Amengual, E. Hernandez-Garcia, M. San Miguel

The dynamics of transient patterns formed by front propagation in extended nonequilibrium systems is considered. Under certain circumstances, the state left behind a front propagating into an unstable homogeneous state can be an unstable periodic pattern. It is found by a numerical solution of a model of the Fréedericksz transition in nematic liquid crystals

R. Preuss, A. Muramatsu, W. von der Linden, F. F. Assaad

The spectral properties of the 1-D Hubbard model are obtained from quantum Monte Carlo simulations using the maximum entropy method. The one-particle excitations are characterized by dispersive cosine-like bands. Velocities for spin- and charge excitations are obtained that lead to a conformal charge c=0.98 +/- 0.05 for the largest system simulated (N=84). A