July 1994 arXiv papers — page 3

J. M. Isidro, A. V. Ramallo

Topological conformal field theories based on superconformal current algebras are constructed. The models thus obtained are the supersymmetric version of the $G/G$ coset theories. Their topological conformal algebra is generated by operators of dimensions $1$, $2$ and $3$ and can be regarded as an extension of the twisted $N=2$ superconformal algebra. These

G. Falci, J. Heins, Gerd Schoen, Gergely T. Zimanyi

We study charging effects and tunneling in the single electron box. Tunneling mixes different charge states and in the nonperturbative regime the charge in the island may be strongly screened. When charge states are nearly degenerate the screening of the charge is strong even in the weak tunneling regime. Virtual tunneling processes reduce both the level spl

A. Cappelli, C. A. Trugenberger, G. R. Zemba

Quantum Hall universality classes can be classified by $W_{1+\infty}$ symmetry. We show that this symmetry also governs the dynamics of quantum edge excitations. The Hamiltonian of interacting electrons in the fully-filled first Landau level is expressed in terms of $W_{1+\infty}$ generators. The spectra for both the Coulomb and generic short-range interacti

G. J. Chaitin

This is yet another version of the course notes in chao-dyn/9407003. Here we use m-expressions more aggressively to further reduce the constants in our information-theoretic incompleteness theorems. Our main theorems are: 1) an N-bit formal axiomatic system cannot enable one to exhibit any specific object with program-size complexity greater than N+c, 2) an

J M Figueroa-O'Farrill, S Stanciu

We re-examine the problem of gauging the Wess-Zumino term of a d-dimensional bosonic sigma-model. We phrase this problem in terms of the equivariant cohomology of the target space and this allows for the homological analysis of the obstruction. As a check, we recover the obstructions of Hull and Spence and also a generalization of the topological terms found

H. E. Boos, V. V. Mangazeev, S. M. Sergeev

Using a modified version of the tetrahedron equations we construct a new family of $N$-state three-dimensional integrable models with commuting two-layer transfer-matrices. We investigate a particular class of solutions to these equations and parameterize them in terms of elliptic functions. The corresponding models contain one free parameter $k$ -- an ellip

P. Elmfors, P. Liljenberg, D. Persson, B. -S. Skagerstam

We present a simple proof of the absence of Bose--Einstein condensation of a relativistic boson gas, in any finite local magnetic field in less than five dimensions. We show that the relativistic charged boson gas exhibit a genuine Meissner--Ochsenfeld effect of the Schafroth form at fixed supercritical density. As in the well--known non--relativistic case,

T. D. Cohen, W. Broniowski

We show that in a uniform medium, the vanishing of a particular condensate along with spontaneously broken symmetry imply the existence of an anomalously light pseudo-Goldstone mode. The consequences for a vanishing chiral condensate in nuclear matter are discussed.

Tomasz Brzezinski

The notion of a translation map in a quantum principal bundle is introduced. A translation map is then used to prove that the cross sections of a quantum fibre bundle $E(B,V,A)$ associated to a quantum principal bundle $P(B,A)$ are in bijective correspondence with equivariant maps $V\to P$, and that a quantum principal bundle is trivial if it admits a cross

Bas V. de Bakker, Jan Smit

We study the average number of simplices $N'(r)$ at geodesic distance $r$ in the dynamical triangulation model of euclidean quantum gravity in four dimensions. We use $N'(r)$ to explore definitions of curvature and of effective global dimension. An effective curvature $R_V$ goes from negative values for low $κ_2$ (the inverse bare Newton constant) to

Victor Chernyak

Using the expansions of the heavy meson decay widths in the heavy quark mass and QCD sum rules for estimates of corresponding matrix elements,\, we calculate the $D^{\pm,o,s}$ decay widths and the $B^{\pm,o,s}$ lifetime differences. The results for D mesons are in agreement with the data,\, while it is predicted that $[Γ(B^o)-Γ(B^-)]/Γ_B\se 4\%\,,$ and the l

Emory F. Bunn, Naoshi Sugiyama

We compare the two-year COBE DMR sky maps with the predictions of cosmological-constant cold dark matter models. Using a Bayesian analysis, we find that the most likely value of the cosmological constant in such a model is Lambda = 0. The data set an upper limit on Lambda of 0.78 (0.85) at 90% confidence, and 0.86 (0.92) at 95% confidence with (without) the

M. Sigrist, D. B. Bailey, R. B. Laughlin

We argue that recent experiments by Kirtley et al. may show evidence of time reversal symmetry breaking in YBCO at crystal grain boundaries. We illustrate this through a Ginzburg-Landau model calculation. Further experimental tests are proposed.

Tyll Krüger, L. D. Pustyl'nikov, Serge Troubetzkoy

We introduce two models, the Fermi-Ulam model in an external field and a one dimensional system of bouncing balls in an external field above a periodically oscillating plate. For both models we investigate the possibility of unbounded motion. In a special case the two models are equivalent.

Spiros A. Argyros, Irene Deliyanni

Two examples of asymptotic $\ell_{1}$ Banach spaces are given. The first, $X_{u}$, has an unconditional basis and is arbitrarily distortable. The second, $X$, does not contain any unconditional basic sequence. Both are spaces of the type of Tsirelson. We thus answer a question raised by W.T.Gowers.

Kh. S. Nirov

The Hamiltonian description for a wide class of mechanical systems, having local symmetry transformations depending on time derivatives of the gauge parameters of arbitrary order, is constructed. The Poisson brackets of the Hamiltonian and constraints with each other and with arbitrary function are explicitly obtained. The constraint algebra is proved to be

Adel Bilal, Ian I. Kogan

We study correlation functions in two-dimensional conformal field theory coupled to induced gravity in the light-cone gauge. Focussing on the fermion four-point function, we display an unexpected non-perturbative singularity structure: coupling to gravity {\it qualitatively} changes the perturbative $(x_1-x_2)^{-1}(x_3-x_4)^{-1}$ singularity into a logarithm

Pijush K. Ghosh, Avinash Khare, Prasanta K. Panigrahi

We show that the topological $B \wedge F$ term in $3+1$ dimensions can be generated via spontaneous symmetry breaking in a generalized Abelian Higgs model. Further, we also show that even in $D$ dimensions $ ( D \geq 3 ) $, a $B \wedge F$ term gives rise to the topological massive excitations of the Abelian gauge field and that such a $B \wedge F$ term can a

E. Corrigan P. E. Dorey, R. H. Rietdijk

The question of the integrability of real-coupling affine toda field theory on a half line is discussed. It is shown, by examining low-spin conserved charges, that the boundary conditions preserving integrability are strongly constrained. In particular, among the cases treated so far, $e_6^{(1)}$, $d_n^{(1)}$ and $a_n^{(1)}, \ n\ge 2$, there can be no free p

R. Brooks, S. J. Gates

The absence of fermion kinetic terms in supersymmetric-BF gauge theories is established. We do this by means of explicit off-shell (superspace) constructions. As part of our study we give the superspace constraints for D=3, N=4 super Yang-Mills along with the D=3, N=4 superconformal algebra. The puzzle we are interested in solving is the fact that the topolo

A. Ferrando, V. Vento

The structure of the quark propagator of $QCD$ in a confining background is not known. We make an Ansatz for it, as hinted by a particular mechanism for confinement, and analyze its implications in the meson and baryon correlators. We connect the various terms in the Källen-Lehmann representation of the quark propagator with appropriate combinations of hadro

Stanley J. Brodsky, SLAC, Peter M. Zerwas, DESY

The collisions of high energy photons produced at an electron-positron collider provide a comprehensive laboratory for testing QCD, electroweak interactions, and extensions of the Standard Model. The luminosity and energy of the colliding photons produced by back-scattering laser beams is expected to be comparable to that of the primary $e^+e^-$ collisions.

Stanley J. Brodsky, SLAC

Measurements of exclusive processes such as electroproduction, photoproduction, and Compton scattering are among the most sensitive probes of proton structure and coherent phenomena in quantum chromodynamics. The continuous electron beam at CEBAF, upgraded in laboratory energy to 10--12 GeV, will allow a systematic study of exclusive, semi-inclusive, and inc

Bernd A. Kniehl

We study inclusive photoproduction of hadrons at HERA via both direct and resolved photons to next-to-leading order (NLO) in the QCD-improved parton model. We predict transverse-momentum ($\pt$) and rapidity ($\ylab$) distributions and compare them with recent data by the H1 Collaboration. To estimate the theoretical error of the predictions, we investigate

Vittorio Del Duca, Carl R. Schmidt

We examine dijet production at large rapidity intervals at Tevatron energies by comparing an exact ${\cal O}(α_s^3)$ calculation with the BFKL approximation, which resums the leading powers of the rapidity interval $y$ to all orders in $α_s$. We analyze the dependence of the exact ${\cal O}(α_s^3)$ calculation on the jet cone-size as a function of $y$, and u

Rathin Adhikari, Biswarup Mukhopadhyaya

If massive invisible particles are pair-produced in a three-body decay, then the energy distribution of the other (visible) product is sensitive to the mass of the invisible pair. We use this fact in the context of a Higgs boson decaying into (i)a Z-boson and two massive neutrinos of a fourth generation, and (ii)a Z and two lightest particles in the minimal

Marco A. Diaz, Tonnis A. ter Veldhuis, Thomas J. Weiler

Vacuum stability implies a lower limit on the mass of the higgs boson in the Standard Model (SM). In contrast, an upper limit on the lightest higgs mass can be calculated in supersymmetric (susy) models. The main uncertainty in each limit is the value of the top mass, which may now be fixed by the recent CDF result. We study the possibility that these bounds

Per Elmfors, Per Liljenberg, David Persson, Bo-Sture Skagerstam

The magnetized relativistic Fermi and Bose gases are studied at finite temperature and density.In the case of the Fermi gas, the contribution to the magnetization from the vacuum becomes dominant for high magnetic fields, when the thermal contribution saturates. In the case of the charged Bose gas, the (paramagnetic) vacuum--magnetization becomes dominant wh

P. G. Silvestrov

The instanton--antiinstanton pair induced asymptotics of perturbation theory expansion for QCD correlators is considered. It is argued that though the true asymptotics is dominated by renormalon, the instanton-induced contribution may dominate in the intermediate asymptotics $n= 5÷15$. Obtained asymptotic formulae are valid for $N_f \le N_c$. For $N_f =N_c$

Gerard Jungman, Marc Kamionkowski

Weakly interacting massive particles (WIMPs) may be indirectly detected by observation of upward muons induced by energetic neutrinos from annihilation of WIMPs that have accumulated in the Sun and/or Earth. Energetic muon neutrinos come from the decays of $τ$ leptons, $c$, $b$, and $t$ quarks, gauge bosons, and Higgs bosons produced by WIMP annihilation. We

Eric Benedict

We consider two programs for quantizing gravity in $1+1$ dimensions, which have appeared in the literature: one using a gauge--theoretic approach and the other following a more conventional ``geometric'' approach. We compare the wave functionals produced by the two different programs by finding matrix elements between the variables of the two theorie

Yuri V. Shtanov

We propose functional approach to the stochastic inflationary universe dynamics. It is based on path integral representation of the solution to the differential equation for the scalar field probability distribution. In the saddle-point approximation scalar field probability distributions of various type are derived and the statistics of the inflationary-his

G. Sardanashvily

Gravitation theory meets spontaneous symmetry breaking when the structure group of the principal linear frame bundle $LX$ over a world manifold $X^4$ is reducible to the Lorentz group $SO(3,1)$. The physical underlying reason of this reduction is Dirac fermion matter possessing only exact Lorentz symmetries. The associated Higgs field is a tetrad gravitation

Ulrich Bunke, Martin Olbrich

For a Riemann surface with cusps we define a theta function using the eigenvalues of the Laplacian and the singularities of the scattering determinant. We provide its meromorphic continuation and discuss its singularities.

Ulrich Bunke, Martin Olbrich

We study the Selberg zeta and the theta function associated to bundles over even-dimensional locally symmetric spaces of rank one.

Ulrich Bunke, Martin Olbrich

This paper is a continuation of our work on theta and zeta functions In the previous papers we considered the case of even dimensional rank one symmetric spaces of non-compact type. The present is concerned with the odd-dimensional case, i.e. with odd-dimensional real hyperbolic manifolds. It is the natural appearence of eta invariants in connection with sup

E. Sweetland, A. C. Finnefrock, W. J. Podulka, M. Sutton

We report time-resolved x-ray scattering measurements of the transient structural response of the sliding {\bf Q}$_{1}$ charge-density-wave (CDW) in NbSe$_{3}$ to a reversal of the driving electric field. The observed time scale characterizing this response at 70K varies from $\sim$ 15 msec for driving fields near threshold to $\sim$ 2 msec for fields well a

Stephan Haas, Elbio Dagotto, Alexander Nazarenko, Jose Riera

Models of strongly correlated electrons that tend to phase separate are studied including a long-range 1/r repulsive interaction. It is observed that charge-density-wave states become stable as the strength of the 1/r term, ${\rm V_{coul}}$, is increased. Due to this effect, the domain of stability of the superconducting phases that appear near phase separat

Giovanni Ferraro

A simple model of a frustrated disordered system is presented. Apart from the (very different) physical interpretation, the model shares many features with that of Sherrington-Kirkpatrick for spin glasses, but, as a consequence of its relative simplicity, its ground state can be exactly determined by numerical methods. This fact allows us to test experimenta

Giovanni Ferraro

In a recent work (Eissfeller and Opper, 1992) a numerical method has been proposed to simulate off-equilibrium zero-temperature parallel dynamics for the SK model without finite size effects. We study the extension of the method to non-zero temperature and sequential dynamics, and analyze more carefully the involved computational problems. We find evidence,

Francisco Dominguez-Adame, Enrique Macia, Angel Sanchez

Incoherent exciton dynamics in one-dimensional perfect lattices with traps at sites arranged according to aperiodic deterministic sequences is studied. We focus our attention on Thue-Morse and Fibonacci systems as canonical examples of self-similar aperiodic systems. Excitons progressively extend over the lattice on increasing time and, in this sense, they a

A. Levy Yeyati, A. Martin-Rodero, F. J. Garcia-Vidal

A microscopic model for describing a superconducting mesoscopic weak link is presented. We consider a model geometry consisting of a narrow channel coupled to wider superconducting electrodes which act as reservoirs fixing the asymptotic values of the complex order parameter. For this model, the Bogoliubov-de Gennes equations are discretized and solved self-

A. Sandvik

A Monte Carlo method for finite-temperature studies of the two-dimensional quantum Heisenberg antiferromagnet with random ferromagnetic bonds is presented. The scheme is based on an approximation which allows for an analytic summation over the realizations of the randomness, thereby significantly alleviating the ``sign problem'' for this frustrated s

Janyce M. Wiebe

Third-person fictional narrative text is composed not only of passages that objectively narrate events, but also of passages that present characters' thoughts, perceptions, and inner states. Such passages take a character's ``psychological point of view''. A language understander must determine the current psychological point of view in order

Tatsuo Yanagita, Kunihiko Kaneko

A coupled map lattice for convection is proposed, which consists of Eulerian and Lagrangian procedures. Simulations of the model not only reproduce a wide-range of phenomena in Rayleigh-Bénard convection experiments but also lead to several prediction of novel phenomena there: For small aspect ratios, the formation of convective rolls, their oscillation, man

C. D. Wilson

Three molecular clouds have been mapped in the nearby metal-poor dwarf irregular galaxy NGC 6822 using the Owens Valley Millimeter-Wave Interferometer. Based on upper limits to the virial masses of the clouds, the CO-to-H2 conversion factor in NGC 6822 is <2.2+/-1.3 times larger than the Galactic value. Conversion factors obtained for Galactic molecular clou

Penny D. Sackett, Heather L. Morrison, Paul Harding, Todd A. Boroson

The presence of unseen halos of ``dark matter&#39;&#39; has long been inferred from the high rotation speeds of gas and stars in the outer parts of spiral galaxies$^{1}$. The volume density of this dark matter decreases less quickly from the galactic center than does that of the luminous mass (such as that in stars), meaning that the dark matter dominates th

Luca Zampieri, Roberto Turolla, Silvia Zane, Aldo Treves

The spectral properties of X--ray radiation produced in a static atmosphere around a neutron star accreting at very low rates are investigated. Previous results by Alme \& Wilson (1973) are extended to the range $10^{-7}\leq L/L_{Edd}\leq 10^{-3}$ to include the typical luminosities, $L\sim 10^{31}-10^{32} \ {\rm ergs\, s^{-1}}$, expected from isolated neutr

Matthias Steinmetz, Ewald Mueller

We present results concerning the internal structure and kinematics of disk galaxies formed in cosmologically motivated simulations. The calculations include dark matter, gas dynamics, radiative cooling, star formation, supernova feedback and metal enrichment. The initial model is a rigidly rotating overdense sphere with a mass of about 8 10^11 Msol which is

Dietmar Rösner, Manfred Stede

TECHDOC is an implemented system demonstrating the feasibility of generating multilingual technical documents on the basis of a language-independent knowledge base. Its application domain is user and maintenance instructions, which are produced from underlying plan structures representing the activities, the participating objects with their properties, relat

Michael A. Doncheski, Stephen Godfrey, K. Andrew Peterson

We suggest a method for probing the quark content of the photon using $b$ tagging at high energy $e^+e^-$ and $eγ$ colliders. We find that heavy quark tagging provides a sensitive and effective probe of the quark content of the photon especially in the low $x$-region where the various models differ the most. This process is complementary to others that have

A. Bashir, M. R. Pennington

In quenched QED we construct a non-perturbative fermion-boson vertex that ensures the fermion propagator satisfies the Ward-Takahashi identity, is multiplicatively renormalizable, agrees with perturbation theory for weak couplings and has a critical coupling for dynamical mass generation that is strictly gauge independent. This is in marked contrast to the r

J. Binnewies, B. A. Kniehl, G. Kramer

We present new sets of fragmentation functions for charged pions and kaons, both at leading and next-to-leading order. They are fitted to TPC data taken at energy $\sqrt s=29$~GeV and describe excellently a wealth of other $e^+e^-$ data on charged-hadron production, ranging from $\sqrt s=5.2$~GeV way up to LEP~1 energy. They also agree with data on the produ

C. H. Oh, K. Singh

We study the relationships among the various forms of the $q$ oscillator algebra and consider the conditions under which it supports a Hopf structure. We also present a generalization of this algebra together with its corresponding Hopf structure. Its multimode extensions are also considered.

K. Andrew Peterson, M. A. Doncheski, Stephen Godfrey

We study the prospects for probing the quark content of the photon using b tagging at high energy electron-photon colliders. We find that heavy quark tagging provides a sensitive and effective probe of the quark content of the photon. Using a 500 GeV $e^+e^-$\ NLC in electron-photon mode, the cross section for $eb_{\gamma}\rightarrow eb$\ can be measured to

T. Dereli, A. Vercin

The differential structure of operator bases used in various forms of the Weyl-Wigner-Groenewold-Moyal (WWGM) quantization is analyzed and a derivative-based approach, alternative to the conventional integral-based one is developed. Thus the fundamental quantum relations follow in a simpler and unified manner. An explicit formula for the ordered products of

A. B. Balantekin, J. R. Bennett, S. Kuyucak

We investigate the effects of nuclear quadrupole and hexadecapole couplings on the average angular momentum in sub-barrier fusion reactions. This quantity could provide a probe for nuclear shapes, distinguishing between prolate vs. oblate quadrupole and positive vs. negative hexadecapole couplings. We describe the data in the O + Sm system and discuss heavie

A. Ono, H. Horiuchi

Collective transverse momentum flow of nucleons and fragments in intermediate energy 40Ar + 27Al collisions is calculated with the antisymmetrized molecular dynamics (AMD). The observed flow and its balance energy are reproduced very well by the calculation with the Gogny force which corresponds to the soft EOS of the nuclear matter. Especially the calculate

S. Dusini, S. Zerbini

The high-temperature expansion for closed superstring one-loop free energy is studied. The Laurent series representation is obtained and its sum is analytically continued in order to investigate the nature of the critical (Hagedorn) temperature. It is found that beyond this critical temperature the statistical sum contribution of the free energy is finite bu

L. Bonora, C. S. Xiong

We show how the two--matrix model and Toda lattice hierarchy presented in a previous paper can be solved exactly: we obtain compact formulas for correlators of pure tachyonic states at every genus. We then extend the model to incorporate a set of discrete states organized in finite dimensional $sl_2$ representations. We solve also this extended model and fin

Piotr Bizoń

It is shown that smooth maps $f: S^3 \rightarrow S^3$ contain two countable families of harmonic representatives in the homotopy classes of degree zero and one.

J. Grundberg, T. H. Hansson

We use arguments taken from the electrodynamics of media to deduce the QCD trace anomaly from the expression for the vacuum energy in the presence of an external color magnetic field.

Martin Markl, Steve Shnider

The aim of this work is to construct a cohomology theory controlling the deformations of a general Drinfel&#39;d algebra. The task is accomplished in three steps. The first step is the construction of a modified cobar complex adapted to a non-coassociative comultiplication. The following two steps each involve a new, highly non-trivial, construction. The fir

Marek Pawlowski, Ryszard Raczka

A Higgsless model for strong, electro-weak and gravitational interactions is proposed. This model is based on the local symmetry group SU(3)xSU(2)xU(1)xC where C is the local conformal symmetry group. The natural minimal conformally invariant form of total lagrangian is postulated. It contains all Standard Model fields and gravitational interaction. Using th

P. E. Gibbs

Open and Closed super-string field theories are constructed in an event-symmetric target space. The partition functions of Statistical and Quantum models are constructed in terms of invariants defined on Lie-algebra representations. An attractive feature of the closed string models is the elegant unification of the space-time symmetries with the gauge symmet

R. B. Zhang

The quantum super Yangian $Y_q(gl(M|N))$ associated with the Perk - Schultz solution of the Yang - Baxter equation is introduced. Its structural properties are investigated, in particular, an extensive study of its central algebra is carried out. A $Z_2$ graded associative algebra epimorphism $Y_q(gl(M|N))--> U_q(gl(M|N))$ is established and constructed expl

T. Eguchi, S. -K. Yang

We discuss the topological $CP^1$ model which consists of the holomorphic maps from Riemann surfaces onto $CP^1$. We construct a large-$N$ matrix model which reproduces precisely the partition function of the $CP^1$ model at all genera of Riemann surfaces. The action of our matrix model has the form ${\rm Tr}\, V(M)=-2{\rm Tr}\, M(\log M -1) +2\sum t_{n,P}{\

Tatsu Takeuchi, Aaron K. Grant, Mihir Worah

We use the Operator Product Expansion (OPE) of quark vacuum polarization functions to show that the dispersion relation of Kniehl and Sirlin will yield the correct result to all orders in $α_s$ when applied to the QCD correction to the leptonic decay width of the Higgs boson.

A. Yu. Ignatiev, G. C. Joshi

It has recently been shown that the neutrino can have non-zero electric charge in a number of gauge theories, including the Minimal Standard Model. Assuming non-zero neutrino charge, we develop a new approach to the solar neutrino problem. The key idea is that the charged neutrinos will be deflected by the Lorentz force while they are crossing the solar magn

G. P. Korchemsky, G. Sterman

We perform infrared factorization of differential rates of radiative and semileptonic inclusive decays of the B meson in the end-point region of photon and charged lepton spectrum, respectively, in the leading heavy quark mass limit. We find that the differential rates are expressed in terms of hard, jet and soft functions, which satisfy evolution equations.

K. A. Bronnikov

Exact static, spherically symmetric solutions to the Einstein-Maxwell-scalar equations, with a dilatonic-type scalar-vector coupling, in $D$-dimensional gravity with a chain of $n$ Ricci-flat internal spaces are considered, with the Maxwell field potential having two nonzero components: the temporal, Coulomb-like one and the one pointing to one of the extra

E. W. Mielke, Y. N. Obukhov, F. W. Hehl

Recently, the {\it spacelike} part of the $SU(2)$ Yang--Mills equations has been identified with geometrical objects of a three--dimensional space of constant Riemann--Cartan curvature. We give a concise derivation of this Ashtekar type (``inverse Kaluza--Klein&#34;) {\it mapping} by employing a $(3+1)$--decomposition of {\it Clifford algebra}--valued torsio

Marco Cavaglià

I present and discuss a class of solutions of the Wheeler-de Witt equation describing wormholes generated by coupling of gravity to the electromagnetic field for Kantowski-Sachs and Bianchi I spacetimes. Since the electric charge can be viewed as electric lines of force trapped in a finite region of spacetime, these solutions can be interpreted as the quantu

Marco Cavaglià

I present quantum wormhole solutions in the Kantowski--Sachs spacetime generated from coupling the gravitational field to the axion and EM fields. These solutions correspond to the classical ones found by Keay and Laflamme and by Cavaglià et al.

F. Alcalde Cuesta

A surjective submersion $π: M \to B$ carrying a field of simplectic structures on the fibres is symplectic if this Poisson structure is minimal. A symplectic submersion may be interpreted as a family of mechanical systems depending on a parameter in $B$. We give some conditions to find a closed form which represent the foliated form $σ$ gluing the symplectic

Alexander Reznikov

I use harmonic maps and minimal surfaces to study quadratic equations in groups.

L. F. Cugliandolo, J. Kurchan, G. Parisi, F. Ritort

We present a family of solvable models of interacting particles in high dimensionalities without quenched disorder. We show that the models have a glassy regime with aging effects. The interaction is controlled by a parameter $p$. For $p=2$ we obtain matrix models and for $p>2$ `tensor&#39; models. We concentrate on the cases $p=2$ which we study analyticall

Jacek Dziarmaga

Vortex solutions in $U(1)\times U(1)$ Chern-Simons theory coupled to a pair of hard-core bosons representing two layers of electrons are analysed. It is shown that there is such a range of parameters $(αβ<γ^{2})$ in which finite charge $(1,0)$ or $(0,1)$ vortices can not exist. Instead the minimal flux quanta are $(1,1)$ hybrids. Their statistical dominance

David A. Egolf, Henry S. Greenside

For the complex Ginzburg-Landau equation on a large periodic interval, we show that the transition from defect- to phase-turbulence is more accurately described as a smooth crossover rather than as a sharp continuous transition. We obtain this conclusion by using a powerful parallel computer to calculate various order parameters, especially the density of sp

Kailash C. Sahu

Massive Compact objects in the halo, known as MACHOs, have been postulated as the origin of a substantial fraction of `dark matter&#39; known to exist in the haloes of galaxies$^{1,2}$. Paczyński$^3$ has suggested that it might possible to detect these low-luminosity objects by their potential to act as gravitational lenses, causing a characteristic brighten

Andrew F. Heckler

The evolution of the electro-weak phase transition, including reheating due to the release of latent heat in shock waves, is calculated for various values of as yet unknown parameters of electro-weak theory such as latent heat and bubble wall surface tension. We show that baryon production, which occurs in the vicinity of the bubble walls of the phase transi

E. T. Vishniac

We suggest a new model for the structure of a magnetic field embedded high $β$ turbulent plasma, based on the popular notion that the magnetic field will tend to separate into individual flux tubes. We point out that interactions between the flux tubes will be dominated by coherent effects stemming from the turbulent wakes created as the fluid streams by the

Geoffrey T. Bodwin, Eric Braaten, G. Peter Lepage

A rigorous QCD analysis of the inclusive annihilation decay rates of heavy quarkonium states is presented. The effective-field-theory framework of nonrelativistic QCD is used to separate the short-distance scale of annihilation, which is set by the heavy quark mass $M$, from the longer-distance scales associated with quarkonium structure. The annihilation de

Frederick J. Ernst

Generalizing a method presented in an earlier paper, we express the complex potentials E and Phi of all stationary axisymmetric electrovac spacetimes that correspond to axis data of the form E(z,0) = (U-W)/(U+W) , Phi(z,0) = V/(U+W) , where U = z^{2} + U_{1} z + U_{2} , V = V_{1} z + V_{2} , W = W_{1} z + W_{2} , in terms of the complex parameters U_{1}, V_{

Frederick J. Ernst

We express the complex potential E and the metrical fields omega and gamma of all stationary axisymmetric vacuum spacetimes that result from the application of two successive quadruple-Neugebauer (or two double-Harrison) transformations to Minkowski space in terms of data specified on the symmetry axis, which are in turn easily expressed in terms of multipol

E. Abdalla, M. C. B. Abdalla

We consider bosonized $QCD_2$, and prove that after rewritting the theory in terms of gauge invariant fields, there exists an integrability condition valid for the quantum theory as well. Furthermore, performing a duality type transformation we obtain an appropriate action for the description of the strong coupling limit, which is still integrable. We also p

Lars Hernquist, Neal Katz, David Weinberg

A small fraction of galaxies appear to reside in dense compact groups, whose inferred crossing times are much shorter than a Hubble time. These short crossing times have led to considerable disagreement about the dynamical state of these systems. We suggest that many of the observed groups are not physically bound but are chance projections of galaxies well-

Hitoshi Konno

We consider the spin $k/2$ XXZ model in the antiferomagnetic regime using the free field realization of the quantum affine algebra $\uqa$ of level $k$. We give a free field realization of the type II $q$-vertex operator, which describes creation and annihilation of physical particles in the model. By taking a trace of the type I and the type II $q$-vertex op

V. Castellani, S. Degl&#39;Innocenti, L. Pulone

In this paper we investigate the hot end of the HB, presenting evolutionary constraints concerning the CM diagram location and the gravity of hot HB stars. According to the adopted evolutionary scenario, we predict an upper limit for HB temperatures of about logTe = 4.45, remarkably cooler than previous estimates. We find that such a theoretical prescription

G. W. Gibbons, R. E. Kallosh

We have found that for extreme dilaton black holes an inner boundary must be introduced in addition to the outer boundary to give an integer value to the Euler number. The resulting manifolds have (if one identifies imaginary time) topology $S^1 \times R \times S^2 $ and Euler number $χ= 0$ in contrast to the non-extreme case with $χ=2$. The entropy of extre

E. L. Wright, P. E. Eisenhardt, G. G. Fazio

Starlight from distant galaxies ($z > 3$) is redshifted into the near infrared band with observed wavelengths from 2-8 $μ$m. Most of the light is emitted by stars that have a peak emission at the 1.6 $μ$m wavelength of the minimum of the H$^-$ opacity. We present simulated images of galaxy and star fields at 3, 4.7 and 8 $μ$m, using the expected performance

V. G. J. Rodgers

Coadjoint orbits of the Virasoro and Kac-Moody algebras provide geometric actions for matter coupled to gravity and gauge fields in two dimensions. However, the Gauss&#39; law constraints that arise from these actions are not necessarily endemic to two-dimensional topologies. Indeed the constraints associated with Yang-Mills naturally arise from the coadjoin

Richard A. Arndt, Igor I. Strakovsky, Ron Workman

An energy-dependent and set of single-energy partial-wave analyses of $NN$ elastic scattering data have been completed. The fit to 1.6~GeV has been supplemented with a low-energy analysis to 400 MeV. Using the low-energy fit, we study the sensitivity of our analysis to the choice of $πNN$ coupling constant. We also comment on the possibility of fitting $np$

Kuniharu Kubodera

An outstanding problem in the study of possible kaon condensation is the striking discrepancy between the results of chiral perturbation theory and those of the PCAC-plus-current-algebra approach. I discuss here what causes this discrepancy and what needs to be done to solve the problem. In addition, I point out the importance of examining the validity of th

J. Resag, C. R. Muenz

The heavy quarkonia (Charmonium \(c\bar{c}\) and Bottomonium \(b\bar{b}\)) are investigated in the framework of the instantaneous BS-equation (Salpeter equation). We parametrize confinement alternatively by a linearly rising scalar or a vector interaction kernel and take into account the one-gluon-exchange (OGE) interaction in the instantaneous approximation

Mourad E. H. Ismail, David R. Masson

The connection between continued fractions and orthogonality which is familiar for $J$-fractions and $T$-fractions is extended to what we call $R$-fractions of type I and II. These continued fractions are associated with recurrence relations that correspond to multipoint rational interpolants. A Favard type theorem is proved for each type. We then study expl

W. T. Gowers, B. Maurey

For a certain class of algebras $\cal A$ we give a method for constructing Banach spaces $X$ such that every operator on $X$ is close to an operator in $\cal A$. This is used to produce spaces with a small amount of structure. We present several applications. Amongst them are constructions of a new prime Banach space, a space isomorphic to its subspaces of c

Harvendra Singh

We consider wormhole solutions in $2+1$ Euclidean dimensions. A duality transformation is introduced to derive a new action from magnetic wormhole action of Gupta, Hughes, Preskill and Wise. The classical solution is presented. The vertex operators corresponding to the wormhole are derived. Conformally coupled scalars and spinors are considered in the wormho

A. Hamid Bougourzi, Luc Vinet

We realize the $U_q(\widehat{sl(2)})$ current algebra at arbitrary level in terms of one deformed free bosonic field and a pair of deformed parafermionic fields. It is shown that the operator product expansions of these parafermionic fields involve an infinite number of simple poles and simple zeros, which then condensate to form a branch cut in the classica

Korkut Bardakci

The conformal fixed points of the generalized Thirring model are investigated with the help of bosonization, the large N limit and the operator product expansion. Necessary conditions on the coupling constants for conformal invariance are derived.