September 1995 arXiv papers — page 6

Oded Agam, Boris L. Altshuler, Anton V. Andreev

The relation between disordered and chaotic systems is investigated. It is obtained by identifying the diffusion operator of the disordered systems with the Perron-Frobenius operator in the general case. This association enables us to extend results obtained in the diffusive regime to general chaotic systems. In particular, the two--point level density corre

H. J. Witt, B. Czerny, P. T. Zycki

We study an accretion disc with a hot continuous corona. We assume that the corona itself accretes and therefore it is powered directly by the release of the gravitational energy and cooled by radiative interaction with the disc. We consider the vertical structure of such a corona and show that the radial infall is accompanied by strong vertical outflow. Suc

D. K. Sinclair

I review the progress that has been made in light hadron spectroscopy from lattice QCD, since the LATTICE'94 conference in Bielefeld.

Jerzy F. Plebanski, Maciej Przanowski, H. Garcia-Compean

It is demonstrated that the action of SU$(N)$ principal chiral model leads in the limit $N \to {\infty}$ to the action for Husain's heavenly equation. The principal chiral model in the Hilbert space $L^2(\Re^1)$ is considered and it is shown, that in this case the chiral equation is equivalent to the Moyal deformation of Husain's heavenly equation. N

B. Sathiapalan

The connection between the proper time equation and the Zamolodchikov metric is discussed. The connection is two-fold: First, as already known, the proper time equation is the product of the Zamolodchikov metric and the renormalization group beta function. Second, the condition that the two-point function is the Zamolodchikov metric, implies the proper time

N. Dorey, J. Hughes, M. Mattis, D. Skidmore

We compute the leading non-analytic correction to the baryon mass in the combined limits m_π-> 0, N_c -> \infty with the product m_πx N_c held fixed. We reproduce the results of Cohen and Broniowski using semiclassical methods rather than heavy-baryon chiral perturbation theory. The calculation is organized to demonstrate: (1) the model independence of our r

Wolfhard Janke, Stefan Kappler

We report numerical estimates of correlation lengths in 2D Potts models from the asymptotic decay of the cluster-diameter distribution. Using this observable we are able to verify theoretical predictions for the correlation length in the disordered phase at the transition point for $q=10$, 15, and 20 with an accuracy of about $1%-2%$. This is a considerable

Wolfhard Janke, Stefan Kappler

We have studied spin-spin correlation functions in the ordered phase of the two-dimensional $q$-state Potts model with $q=10$, 15, and 20 at the first-order transition point $β_t$. Through extensive Monte Carlo simulations we obtain strong numerical evidence that the correlation length in the ordered phase agrees with the exactly known and recently numerical

A. I. Liechtenstein, O. Gunnarsson, O. K. Andersen, R. M. Martin

We analyze the generic features of the energy spectrum for two coupled CuO$_2$ layers with a realistic extended Hubbard model. The quasiparticle bands exhibit flat regions near X(Y) points in the Brillouin zone with a large reduction of the bonding-antibonding splitting, and pinning of extended van-Hove singularity to the Fermi level, which is more efficient

Reinhold Egger, Hermann Grabert

We study Friedel oscillations in one-dimensional electron liquid for arbitrary electron-electron interaction and arbitrary impurity strength. For Luttinger liquid leads, the Friedel oscillations decay as x^-g far away from the impurity, where g is the interaction constant. For a weak scatterer, a slower decay is found at intermediate distances from the impur

R. W. Rollins, P. Parmananda, P. Sherard, H. D. Dewald

The recursive proportional feedback (RPF) algorithm for controlling chaos is described and applied to control chemical chaos observed during the electrodissolution of a rotating copper disk in a sodium acetate/acetic acid buffer. Experimental evidence is presented to indicate why the RPF method was used and the theoretical robustness of the algorithm is disc

Yu. V. Ralchenko, L. A. Vainshtein

We report here on calculation of probabilities of intercombination transitions $2s^2$ $^1S_0$ - $2s2p$ $^3P_1$, $2s3p$ $^3P_1$ for Be-like ions along the isoelectronic sequence for large range of $Z$. Our results obtained with the $1/Z$ expansion method agree well with experimental data including the recent ones.

D. A. Verner, G. J. Ferland

We present new calculations and analytic fits to the rates of radiative recombination towards H-like, He-like, Li-like and Na-like ions of all elements from H through Zn (Z=30). The fits are valid over a wide range of temperature, from 3 K to 10**9 K.

A. Ghosh, P. Mitra

For extremal black holes, the thermodynamic entropy is not proportional to the area. The general form allowed by thermodynamics is worked out for three classes of extremal black hole solutions of string theory and shown to be consistent with the entropy calculated from the density of elementary string states. On the other hand, the entanglement entropy does

J. V. Selinger, R. L. B. Selinger

Recent experiments have found that polyisocyanates composed of a mixture of opposite enantiomers follow a chiral ``majority rule:'' the chiral order of the copolymer, measured by optical activity, is dominated by whichever enantiomer is in the majority. We explain this majority rule theoretically by mapping the random copolymer onto the random-field

Andreas Hoecker, Vakhtang Kartvelishvili

Distributions measured in high energy physics experiments are usually distorted and/or transformed by various detector effects. A regularization method for unfolding these distributions is re-formulated in terms of the Singular Value Decomposition (SVD) of the response matrix. A relatively simple, yet quite efficient unfolding procedure is explained in detai

Ctirad Klimcik

A description of dual non-Abelian duality is given, based on the notion of the Drinfeld double. The presentation basically follows the original paper \cite{KS2}, written in collaboration with P. \v Severa, but here the emphasis is put on the algebraic rather than the geometric aspect of the construction and a concrete example of the Borelian double is worked

M. A. Clayton

The dynamics of a class of nonsymmetric gravitational theories is presented in Hamiltonian form. The derivation begins with the first-order action, treating the generalized connection coefficients as the canonical coordinates and the densitised components of the inverse of the fundamental tensor as conjugate momenta. The phase space of the symmetric sector i

C. R. Hu, S. G. Matinyan, B. Muller, D. Sweet

We present numerical simulations of colliding wave packets in spontaneously broken SU(2) Yang-Mills-Higgs theory. Compared with pure Yang-Mills theory, introducing the Higgs field leads to new aspects in the dynamics of the system. The evolution of the gauge field and the Higgs field is investigated as a function of the amplitude of the wave packets and of t

Stefano Liberati, Giuseppe Pollifrone

In this work a deep relation between topology and thermodynamical features of manifolds with boundaries is shown. The expression for the Euler characteristic, through the Gauss- Bonnet integral, and the one for the entropy of gravitational instantons are proposed in a form which makes the relation between them self-evident. A generalization of Bekenstein-Haw

W. Bietenholz, U. -J. Wiese

We use perturbation theory to construct perfect lattice actions for fermions and gauge fields by blocking directly from the continuum. When one uses a renormalization group transformation that preserves chiral symmetry the resulting lattice action for massless fermions is chirally symmetric but nonlocal. When the renormalization group transformation breaks c

Kingman Cheung, Wai-Yee Keung, Tzu Chiang Yuan

The direct production rate of $J/ψ$ via the color-octet mechanism is calculated at the $Z$ resonance. The color-octet production process $Z\to J/ψq \bar q$ is shown to have a substantial branching ratio as well as a distinctive energy spectrum, which can be used as a powerful tool to distinguish from the color-singlet direct production of the $J/ψ$.

Jean-Philippe Bouchaud, Giulia Iori, Didier Sornette

We present a theory of option pricing and hedging, designed to address non-perfect arbitrage, market friction and the presence of `fat' tails. An implied volatility `smile' is predicted. We give precise estimates of the residual risk associated with optimal (but imperfect) hedging.

Ya. M. Blanter, A. D. Mirlin

A rigorous microscopic calculation of the polarizability of disordered mesoscopic particles within the grand canonical ensemble is given in terms of the supersymmetry method. The phenomenological result of Gor'kov and Eliashberg is confirmed. Thus the underlying assumptions of their method are justified. This encourages application of RMT in the Gor'

Eugene Golowich, Joachim Kambor

A general class of inverse-moment sum rules was previously derived by the authors in a chiral perturbation theory (ChPT) study at two-loop order of the isospin and hypercharge vector-current propagators. Here, we address the evaluation of the inverse-moment sum rules in terms of existing data and theoretical constraints. Two kinds of sum rules are seen to oc

D. Schaerer

We present a simple analytical method to describe the structure of a spherically expanding envelope with strong mass outflow. The structure is consistently connected to the hydrostatic stellar interior and provides an adequate description of the outer boundary conditions for stellar models with large mass loss rates. We apply our treatment to evolutionary mo

Y. V. Fyodorov, O. A. Chubykalo, F. M. Izrailev, G. Casati

Random banded matrices with linearly increasing diagonal elements are recently considered as an attractive model for complex nuclei and atoms. Apart from early papers by Wigner \cite{Wig} there were no analytical studies on the subject. In this letter we present analytical and numerical results for local spectral density of states (LDOS) for more general cas

F. Barbarin, E. Ragoucy, P. Sorba

Relaxing first-class constraint conditions in the usual Drinfeld-Sokolov Hamiltonian reduction leads, after symmetry fixing, to realizations of W algebras expressed in terms of all the J-current components. General results are given for G a non exceptional simple (finite and affine) algebra. Such calculations directly provide the commutant, in the (closure o

I. F. Ginzburg

We study $μ^+μ^-$ collision with production of some state $F$ (for example, $F= W^+$) and $(e\barν)$ system with the effective mass, which is less than muon mass. In this case the momentum $k$, transferred from $μ$ to $e\barν$ system (virtual neutrino momentum), can be time--like. The path of integration over $k^2$ goes through the pole at $k^2=0$. It gives

L. M. Kuang, Xin Chen, G. H. Chen, M. L. Ge

A new master equation is derived for the Janes-Cummings model.

S. Ya. Startsev

There are considered differential substitutions of the form $v=P(x,u,u_{x})$ for which there exists a differential operator $H=\sum^{k}_{i=0} α_{i} D^{i}_{x}$ such that the differential substitution maps the equation $u_{t}=H[s(x,P,D_{x}(P),...,D^{k}_{x}(P))]$ into an evolution equation for any function $s$ and any nonnegative integer $k$. All differential s

Bijan Saghai, Frank Tabakin

Spin observables for the reaction $γp \rightarrow K^+ Λ$ are examined using three recent dynamical models and are compared to the general features of such observables deduced earlier by Fasano, Tabakin and Saghai. These general features, such as the energy dependence of spin observables and the location of nodes in their angle dependence, are realized. Sever

T. S. Kosmas, J. D. Vergados

The momentum transfer dependence of the total cross section for elastic scattering of cold dark matter candidates, i.e. lightest supermymmetric particle (LSP), with nuclei is examined. We find that even though the energy transfer is small ($\le 100 KeV$) the momentum transfer can be quite big for large mass of the LSP and heavy nuclei. The total cross sectio

S. A. Voloshin, W. E. Cleland

The effects of anisotropic transverse collective flow on the HBT correlation function is studied. There exist three different physics contributions related to flow which affect the correlation function: anisotropic source shape, anisotropic space-momentum correlations in pion emission, and the effects related to the HBT measurement of the size of a moving so

J. J. de Swart, R. A. M. M. Klomp, M. C. M. Rentmeester, Th. A. Rijken

A review is given of the various Nijmegen potentials. Special attention is given to some of the newest developments, such as the extended soft-core model, the high-quality potentials, and the Nijmegen optical potentials for NN.

Saharon Shelah

The canonization theorem says that for given m,n for some m^* (the first one is called ER(n;m)) we have: for every function f with domain [{1, ...,m^*}]^n, for some A in [{1, ...,m^*}]^m, the question of when the equality f({i_1, ...,i_n})=f({j_1, ...,j_n}) (where i_1< ... <i_n and j_1 < ... < j_n are from A) holds has the simplest answer: for some v subsete

James Cummings, Saharon Shelah

We prove some consistency results about b(lambda) and d(lambda), which are natural generalisations of the cardinal invariants of the continuum b and d. We also define invariants b_cl(lambda) and d_cl(lambda), and prove that almost always b(lambda) = b_cl(lambda) and d(lambda)=d_cl(lambda)

James Cummings, Saharon Shelah

We show that it is consistent with ZFC (relative to large cardinals) that every infinite Boolean algebra B has an irredundant subset A such that 2^{|A|} = 2^{|B|}. This implies in particular that B has 2^{|B|} subalgebras. We also discuss some more general problems about subalgebras and free subsets of an algebra. The result on the number of subalgebras in a

Saharon Shelah

We prove the consistency of: if B_1, B_2 are Boolean algebra satisfying the c.c.c. and the 2^{aleph_0}-c.c. respectively then B_1 x B_2 satisfies the 2^{aleph_0}-c.c.

Saharon Shelah

A characteristic result is that if 2^{aleph_0}< mu < mu^+< lambda = cf(lambda)< mu^{aleph_0}, then among the separable reduced p-groups of cardinality lambda which are (< lambda)-stable there is no universal one.

H. Aratyn, L. A. Ferreira, J. F. Gomes, A. H. Zimerman

We formulate the constrained KP hierarchy (denoted by \cKP$_{K+1,M}$) as an affine ${\widehat {sl}} (M+K+1)$ matrix integrable hierarchy generalizing the Drinfeld-Sokolov hierarchy. Using an algebraic approach, including the graded structure of the generalized Drinfeld-Sokolov hierarchy, we are able to find several new universal results valid for the \cKP hi

Xavier Gracia, Josep M. Pons

Noether&#39;s symmetry transformations for higher-order lagrangians are studied. A characterization of these transformations is presented, which is useful to find gauge transformations for higher-order singular lagrangians. The case of second-order lagrangians is studied in detail. Some examples that illustrate our results are given; in particular, for the l

Vicente Azcoiti, Victor Laliena, Xiang-Qian Luo

We propose a new method for the study of the chiral properties of the ground state in QFT&#39;s based on the computation of the probability distribution function of the chiral condensate. It can be applied directly in the chiral limit and therefore no mass extrapolations are needed. Furthermore this approach allows to write up equations relating the chiral c

L. L. Salcedo

It is shown, under mild assumptions, that classical degrees of freedom dynamically coupled to quantum ones do not inherit their quantum fluctuations. It is further shown that, if the assumptions are strengthen by imposing the existence of a canonical structure, only purely classical or purely quantum dynamics are allowed.

P. J. Ariasa, L. Leal, A. Restuccia

A non-abelian ``self-dual&#39;&#39; massive gauge theory describing a massive spin one physical mode is presented. The action is expressed in terms of two independent connections on a principle bundle over $2+1$ space-time. The kinetic terms are respectively a Chern-Simons and a $BF$ lagrangians, while the gauge invariant interaction is expressed in terms of

Ion I. Cotăescu

A possible generalization of the technique of the standard model to $SU(n)\otimes U(1)$ gauge models is proposed. A special Higgs mechanism and a new kind of Yukawa couplings in unitary gauge are introduced. These allow us to obtain a general method of deriving boson mass spectrum and coupling coefficients which will be used to find an exact solution of the

Alan R. White

We discuss the observed scaling of the small-x diffractive and total deep-inelastic structure functions at HERA. We argue that the parton interpretation of Buchmüller and Hebecker can be understood within QCD as the appearance of the Pomeron in a Super-Critical phase. In diffractive hard scattering, the Pomeron appears as reggeized gluon exchange in a color-

Jose W. F. Valle

A brief sketch is given of the present observational status and future prospects of the physics of neutrino mass, including a survey of the various theoretical schemes of neutrino mass generation. Emphasis is given to those which are motivated by present experimental hints from solar and atmospheric neutrinos, as well as from cosmological data related to the

J. Bartels, L. N. Lipatov, M. Wüsthoff

We show that the transition vertex: two reggeized gluons $\to$ four reggeized gluons is invariant under Möbius transformations. This provides an important step in defining a conformally invariant effective field theory for QCD in the Regge limit.

Herbert Nachbagauer

We propose an non-standard method to calculate non-equilibrium physical observables. Considering the generic example of an anharmonic quantum oscillator, we take advantage of the fact that the commutator algebra of second order polynomials in creation/annihilation operators closes. We solve the von~Neumann equation for the density-operator exactly in the mea

N. V. Makhaldiani, Z. K. Silagadze

The critical charge $Z_c$ is estimated for elementary particles using a Newton-Wigner position operator inspired model. Particles with $Z \sim Z_c$ (maxicharged particles), if they exist at all, can have unusual properties which turn them into elusive objects not easy to detect. Dirac&#39;s magnetic poles have a (magnetic) charge $g\gg Z_c$. This gives one m

C. Bernard, T. Blum, C. DeTar, Steven Gottlieb

We present new results in an ongoing study of the nature of the high temperature crossover in QCD with two light fermion flavors. These results are obtained with the conventional staggered fermion action at the smallest lattice spacing to date---approximately 0.1 fm. Of particular interest are a study of the temperature of the crossover, an important indicat

Robert Shrock

We report new results on complex-temperature properties of Ising models. These include studies of the $s=1/2$ model on triangular, honeycomb, kagomé, $3 \cdot 12^2$, and $4 \cdot 8^2$ lattices. We elucidate the complex--$T$ phase diagrams of the higher-spin 2D Ising models, using calculations of partition function zeros. Finally, we investigate the 2D Ising

W. Bietenholz, A. Pochinsky, U. -J. Wiese

Twelve years ago, Haldane formulated his famous conjecture for 1-d antiferromagnetic quantum spin chains. In the context of the 2-d O(3) model with a θterm, it predicts a phase transition at θ= π, which has not yet been verified reliably. To simulate this we use the Wolff cluster algorithm together with an improved estimator for the topological charge distri

Christian Holm, Wolfhard Janke

We study 2D quantum gravity on spherical topologies using the Regge calculus approach. Our goal is to shed new light upon the validity of the Regge approach to quantum gravity, which has recently been questioned in the literature. We incorporate an $R^2$ interaction term and investigate its effect on the value of the string susceptibility exponent $γ_{\rm st

Peter N. Meisinger, Michael C. Ogilvie

The Polyakov loop and the chiral condensate are used as order parameters to explore analytically the possible phase structure of finite temperature QCD. Nambu-Jona-Lasinio models in a background temporal gauge field are combined with a Polyakov loop potential in a form suitable for both the lattice and the continuum. Three possible behaviors are found: a fir

UKQCD Collaboration, presented by David Richards

We present a study in the quenched approximation of the $B$ parameter $B_B$ and the decay constant $f_B$ using heavy-quark propagators implemented in the static approximation, and light-quark propagators computed using an $O(a)$-improved fermion action. We find a value of $\Bbstat$ close unity, and discuss the systematic errors entering into the calculation.

A. Gonzalez-Arroyo, A. Montero

We observe a strong correlation between the decrease in the number of action density peaks in SU(2) Yang-Mills configurations with cooling and that of the string tension. The nature and distribution of these peaks is investigated. The relationship with monopole currents after the abelian projection is also considered.

R. R. Caldwell

We further clarify how scalar metric perturbations are amplified in an inflationary cosmology. We first construct a simple, analytic model of an inflationary cosmology in which the expansion scale factor evolves continuously from an inflationary era to a radiation-dominated era. From this model, it is clear to see how scalar perturbations are amplified. Seco

G. A. Kohring

Particle diffusion in rotating drums is studied via computer simulations using a full 3-D model which does not involve any arbitrary input parameters. The diffusion coefficient for single-component systems agree qualitatively with previous experimental results. On the other hand, the diffusion coefficient for two-component systems is shown to be a highly non

Francois David

Recent progresses in the understanding of the scaling behavior of self-avoiding flexible polymerized membranes (tethered manifolds) are reviewed. They rely on a new general renormalization group approach for a class of models with non-local singular interactions. This approach allows to prove the existence of a epsilon-expansion for the scaling exponents, an

Le-man Kuang, Guang-hong Chen, Mo-lin Ge, Xin Chen

An alternative approach to the Jaynes-Cummings model (JCM) with dissipation at a finite enviromental temperature is presented in terms of a new master equation under Born-Markovian approximations. An analytic solution of the dissipation JCM is obtained. A variety of physical quantities of interest are calculated analytically. Dynamical properties of the atom

Krzysztof Byczuk, Jozef Spalek

We derive the expressions for the transition temperature $(T_{c})$, and the spatial dependence of the superconducting gap for a multilayer high-$T_{c}$ superconductor composed of groups of tightly spaced planes separated by a larger distance. The results are compared with experiment and provide a strong support for an interlayer hopping as the driving force

Guang-Hong Chen, Mo-lin Ge

We show that there exists quantum group symmetry $ sl_{q}(2) $ in the fractional quantum Hall effect (FQHE) and this symmetry governs the degeneracy of ground-state level. Under the periodic boundary condition, the degeneracy of the ground state is related to the cyclic representation of SL_q(2). We also discuss the influence of impurity.

Guang-Hong Chen, Le-Man Kuang, Mo-lin Ge

We show that there is a kind of quantum group symmetry $ sl_{q}(2) $ in the usual Landau problem and it is this quantum group symmetry that governs the degeneracy of Landau levels. We find that under the periodic boundary condition, the degree of degeneracy of Landau levels is finite, and it just equals the dimension of the irreducible cyclic representation

Mo-lin Ge, Kang Xue, Yiwen Wang

This is an introduction to the physical pictures of {\em Yangian} symmetry. All the discussions are based on the RTT relations which have been known to be related to the Hamiltonian formulations for quantum integrable systems. The explicit calculations of {\em Yangian} associated with $gl(2)$ are given through solving the RTT relations. It contains the Drinf

Ke-Man Kuang, Yiwen Wang, Mo-lin Ge

In this paper, we study the supercurrent in a mesoscopic Josephson junction (MJJ) and its quantum statistical properties in the presence of nonclassical light fields. We investigate in detail the influence of external nonclassical light fields on current-voltage step structures of the MJJ. We also study in detail quantum statistical properties of the supercu

P. W. Leung, R. J. Gooding

We present results of an exact diagonalization calculation of the spectral function $A(\bf k, ω)$ for a single hole described by the $t$--$J$ model propagating on a 32--site square cluster. The minimum energy state is found at a crystal momentum ${\bf k} = ({π\over 2}, {π\over 2})$, consistent with theory, and our measured dispersion relation agrees well wit

Conny Aerts, Kevin Krisciunas

We have investigated the F0V star V398\,Aurigae (= 9 Aur) under the assumption that it is undergoing non-radial gravity mode oscillations and that the two principal periods given by Krisciunas et al. (1995) are correct. We find that the two periods are manifestations of an $\ell=3, |m|=1$ spheroidal mode and its toroidal corrections due to the rotation of th

F J Summers

This general talk is geared toward non-specialists and addresses three questions: (1) What types of cosmological simulations are done? (2) What are the relevant problems to address and what results can one expect? (3) How can one tell if the results are reasonable?

M. Bellazzini, F. Fusi Pecci, F. R. Ferraro

The central surface brightness ($μ_V(0)$) of the dwarf spheroidal satellites of our own Galaxy is found to correlate with their distance from the Galactic Center ($R_{GC}$). This observational evidence suggests that environmental effects could strongly influence their structure. This suggestion is further supported by a clear-cut bivariate correlation linkin

Arturo Serna, Daniel Gerbal

We propose a new hierarchical method which uses dynamical arguments to find and describe substructures in galaxy clusters. This method (hereafter h--method or h--analysis) uses a hierarchical clustering analysis to determine the relationship between galaxies according to their relative binding energies. We have tested from N-body simulations, the two followi

Michael S. Briggs, William S. Paciesas, Geoffrey N. Pendleton, Charles A. Meegan

We use dipole and quadrupole statistics to test the large-scale isotropy of the first 1005 gamma-ray bursts observed by the Burst and Transient Source Experiment (BATSE). In addition to the entire sample of 1005 gamma-ray bursts, many subsets are examined. We use a variety of dipole and quadrupole statistics to search for Galactic and other predicted anisotr

Vipul Periwal

This paper is being revised to make it intelligible, and to incorporate some corrections.

Vipul Periwal

Curci and Ferrari found a unique BRS-invariant action for non-Abelian gauge theories which includes a mass term for the gauge bosons. I analyze this action. While the BRS operator is not nilpotent, the Zinn-Justin equation generalizes in a simple way so that the renormalization of the theory is consistent with the infrared regularization provided by the mass

R. Narayanan, H. Neuberger

Some key features of continuum chiral fermions are shown to be satisfied by the overlap.

J. Maly, D. Z. Liu, K. Levin

We discuss the allowed order parameter symmetries in multi-layer cuprates and their physical consequences using highly non-specific forms of the inter- and intra-plane interactions. Within this framework, the bi-layer case is discussed in detail with particular attention paid to the role of small orthorhombic distortions as would derive from the chains in YB

Cristina Manuel

Classical transport theory for colored particles is reviewed and used to derive the hard thermal loops of QCD. A perturbative study of the non-Abelian transport equations that preserves their gauge symmetry is used to compute the induced color current in a hot quark-gluon plasma. From this approach the effective action of hard thermal loops can be derived. T

Michael Pichowsky, Cetin Savkli, Frank Tabakin

An analysis of all possible polarization observables for the case of vector meson photoproduction from a nucleon target is presented. The question of which observables are needed to determine completely the basic photoproduction amplitudes and the relationships between spin observables are addressed.

J. R. Shepard, J. A. McNeil

This paper has been withdrawn to address an omission. It will be resubmitted in the near future.

Mo-lin Ge, Lei Wang

The quantum dynamics of two-level systems under classical oscillator heat bath is mapped to the classical one of a charged particle under harmonic oscillator potential plus a magnetic field in a plane. The behavior of eigenstates and tunneling and localization are studied in detail. The broken symmetry condition and Langevin-like dissipative equation of moti

Sara Collins, Robert G. Edwards, Urs M. Heller, John Sloan

We present results of quenched $SU(3)$ hadron spectroscopy using $\order(a)$ improved Wilson fermions. The configurations were generated using an $\order(a^2)$ improved 6-link $SU(3)$ pure gauge action at $\beta$'s corresponding to lattice spacings of $0.43$, $0.25$, $0.20$, $0.18$, and $0.15$ fm. We find evidence that fermionic scaling violations are consis

Mi Xie, Bai-Qi Jin, Zhong-Qi Ma

The relations between $L^{\pm}$ operators and the generators in the quantum enveloping algebras are studied. The $L^{\pm}$ operators for $U_{q}A_{N}$ and $U_{q}G_{2}$ algebras are explicitly expressed by the generators as examples.

P. C. Aichelburg, H. Balasin

We generalize the classification of (non-vacuum) pp-waves \cite{JEK} based on the Killing-algebra of the space-time by admitting distribution-valued profile functions. Our approach is based on the analysis of the (infinite-dimensional) group of ``normal-form-preserving&#39;&#39; diffeomorphisms.

P. Poulose, Saurabh D. Rindani

In the presence of an electric dipole coupling of $t \bar t$ to a photon, and an analogous ``weak&#34; dipole coupling to the $Z$, $CP$ violation in the process $e^+e^- \rightarrow t \bar t$ leads to the polarization of the top and anti-top. This polarization can be analyzed by studying the energy and angular distributions of a decay charged lepton (anti-lep

W. Franzki, J. Jersák, R. Welters

By means of the Lee-Shrock transformation we generalize the 2D Gross-Neveu (GN$_2$) model to a U(1) gauge theory with charged fermion and scalar fields in 2D ($χU ϕ_2$ model). The $χU ϕ_2$ model is equivalent to the GN$_2$ model at infinite gauge coupling. We show that the dynamical fermion mass generation and asymptotic freedom in the effective four-fermion

Amol S. Dighe

Some new methods for the extraction of CKM phases $α$ and $γ$ using flavor SU(3) symmetry have been suggested through the construction of rigid polygons in the complex plane with sides equal to the decay amplitudes of B mesons into two mesons belonging to the light (charmless) pseudoscalar octet. These rigid polygons incorporate all the possible amplitude tr

Clifford V. Johnson, Nemanja Kaloper, Ramzi R. Khuri, Robert C. Myers

Recently a great deal of evidence has been found indicating that type IIA string theory compactified on K3 is equivalent to heterotic string theory compactified on T^4. Under the transformation which relates the two theories, the roles of fundamental and solitonic string solutions are interchanged. In this letter we show that there exists a solitonic membran

Yunbo Zeng, Jarmo Hietarinta

We construct the classical Poisson structure and $r$-matrix for some finite dimensional integrable Hamiltonian systems obtained by constraining the flows of soliton equations in a certain way. This approach allows one to produce new kinds of classical, dynamical Yang-Baxter structures. To illustrate the method we present the $r$-matrices associated with the

M. Sanjay Kumar, Avinash Khare

We show that for the strictly isospectral Hamiltonians, the corresponding coherent states are related by a unitary transformation. As an illustration, we discuss, the example of strictly isospectral one-dimensional harmonic oscillator Hamiltonians and the associated coherent states.

P. Girard, R. MacKenzie

We apply the formalism of path integrals in multiply connected spaces to the problem of two anyons.

V. Topor Pop, H. Rebel

The HIJING and VENUS models of relativistic hadron-nucleus and nucleus-nucleus collisions are used to study interactions of proton and nuclei with nitrogen, specific for the extensive air shower developments initiated by cosmic rays in the atmosphere. The transverse energy,transverse momenta and secondary particles produced spectra as well as their energy an

M. Arik, T. Rador, R. M. Mir-Kasimov

The relativistic finite-difference SUSY Quantum Mechanics (QM) is developed. We show that it is connected in a natural way with the q-deformed SUSY Quantum Mechanics. Simple examples are given.

Aleksandar R. Bogojević, Dragan Popović

We present a way for calculating the Lagrangian path integral measure directly from the Hamiltonian Schwinger--Dyson equations. The method agrees with the usual way of deriving the measure, however it may be applied to all theories, even when the corresponding momentum integration is not Gaussian. Of particular interest is the connection that is made between

Augusto Sagnotti

Open-string theories may be related to suitable models of oriented closed strings. The resulting construction of ``open descendants&#39;&#39; is illustrated in a few simple cases that exhibit some of its key features.

Ivan G. Avramidi

A new algebraic approach for calculating the heat kernel for the Laplace operator on any Riemannian manifold with covariantly constant curvature is proposed. It is shown that the heat kernel operator can be obtained by an averaging over the Lie group of isometries. The heat kernel diagonal is obtained in form of an integral over the isotropy subgroup.

Ivan G. Avramidi

The covariant technique for calculating the heat kernel asymptotic expansion for an elliptic differential second order operator is generalized to manifolds with boundary. The first boundary coefficients of the asymptotic expansion which are proportional to $t^{1/2}$ and $t^{3/2}$ are calculated. Our results coincide with completely independent results of pre

Ivan G. Avramidi

A short informal overview about recent progress in the calculation of the effective action in quantum gravity is given. I describe briefly the standard heat kernel approach to the calculation of the effective action and discuss the applicability of the Schwinger - De Witt asymptotic expansion in the case of strong background fields. I propose a new ansatz fo

Metin Gurses, Emre Sermutlu

We classify the spherically symmetric solutions of the Einstein-Maxwell Dilaton field equations in D dimensions and find some exact solutions of the string theory at all orders of the string tension parameter. We also show the uniqueness of the black hole solutions of this theory in static axially symmetric spacetimes.

Ivan G. Avramidi

This paper is an overview on our recent results in the calculation of the heat kernel in quantum field theory and quantum gravity. We introduce a deformation of the background fields (including the metric of a curved spacetime manifold) and study various asymptotic expansions of the heat kernel diagonal associated with this deformation. Especial attention is