November 1992 arXiv papers — page 5

Thomas Kalkreuter

Multigrid (MG) methods for the computation of propagators of staggered fermions in non-Abelian gauge fields are discussed. MG could work in principle in arbitrarily disordered systems. The practical variational MG methods tested so far with a ``Laplacian choice'' for the restriction operator are not competitive with the conjugate gradient algorithm o

C. Klimčík, P. Kolník

Family of exact spacetimes of D=3 Einstein gravity interacting with massless scalar field is obtained by suitable dimensional reduction of a class of D=4 plane-symmetric Einstein vacua. These D=3 spacetimes describe collisions of line-fronted asymptotically null excitations and are generically singular to the future. The solution for the scalar field can be

David Hochberg, Thomas W. Kephart

We construct an explicit class of dynamic lorentzian wormholes connecting Friedmann-Robertson-Walker (FRW) spacetimes. These wormholes can allow two-way transmission of signals between spatially separated regions of spacetime and could permit such regions to come into thermal contact. The cosmology of a network of early Universe wormholes is discussed.

M. De Francia, G. Goya, R. C. Mercader, H. Vucetich

Accurate limits for the violation of the Principle of Equivalence have been found from the comparison of the redshifts of two identical nuclear species in different chemical environments.

Theodore C. Hsu, J. C. Angles d'Auriac

The repartition of the separation between energy levels of various isotropic S=1/2 antiferromagnetic chains is studied numerically with the aim of investigating the transition from integrable to non-integrable systems. We begin by displaying the level separation distribution of the integrable Bethe chain. Then two non-integrable systems, two coupled chains a

A. Mezhlumian, S. A. Molchanov

We give an account of matter and (basically) a solution of a new class of problems synthesizing percolation theory and branching diffusion processes. They led us to realizing a novel type of stochastic processes, namely branching processes with diffusion on the space of parameters distinguishing the branching `particles' each other.

Paul Baillon, Alain Bouquet, Yannick Giraud-Héraud, Jean Kaplan

The presence of brown dwarfs in the dark galactic halo could be detected through their gravitational lensing effect and experiments under way monitor about one million stars to observe a few lensing events per year. We show that if the photon flux from a galaxy is measured with a good precision, it is not necessary to resolve the stars and besides more event

Ulf H. Danielsson

In this work the quantum theory of two dimensional dilaton black holes is studied using the Wheeler De Witt equation. The solutions correspond to wave functions of the black hole. It is found that for an observer inside the horizon, there are uncertainty relations for the black hole mass and a parameter in the metric determining the Hawking flux. Only for a

G. Grignani, G. Nardelli

In the context of a Poincaré gauge theoretical formulation, pure gravity in 3+1-dimensions is dimensionally reduced to gravity in 2+1-dimensions with or without cosmological constant $Λ$. The dimensional reductions are consistent with the gauge symmetries, mapping ISO(3, 1) gauge transformations into ISO(2,1) ones. One of the reductions leads to Chern-Simons

Sandip P. Trivedi

Extremal black holes are studied in a two dimensional model motivated by a dimensional reduction from four dimensions. Their quantum corrected geometry is calculated semiclassically and a mild singularity is shown to appear at the horizon. Extensions of the geometry past the horizon are not unique but there are continuations free from malevolent singularitie

L. Frankfurt, W. R. Greenberg, G. A. Miller, M. Strikman

The assumption that a small point-like configuration does not interact with nucleons leads to a new set of sum rules that are interpreted as models of the baryon-nucleon interaction. These models are rendered semi-realistic by requiring consistency with data for cross section fluctuations in proton-proton diffractive collisions.

Jörg Brendle, Haim Judah, Saharon Shelah

In this work we use a notion of rank first introduced by James Baumgartner and Peter Dordal and later developed independently by the third author to show that adding a Hechler real has strong combinatorial consequences. We prove: 1) assuming omega_1^V = omega_1^L, there is no real in V[d] which is eventually different from the reals in L[d], where d is Hechl

Jörg Brendle

Given a group G, we let Z(G) denote its center, G' its commutator subgroup, and Phi (G) its Frattini subgroup (the intersection of all maximal proper subgroups of G). Given U leq G, we let N_G (U) stand for the normalizer of U in G. A group G is FC iff every element g in G has finitely many conjugates. A p-group E is called extraspecial iff Phi (E) = E&#

A. Das, C. A. P. Galvao

We show how the supersymmetric KdV equation can be obtained from the self-duality condition on Yang-Mills fields in four dimension associated with the graded Lie algebra OSp(2/1). We also obtain the hierarchy of Susy KdV equations from such a condition. We formulate the Susy KdV hierarchy as a vanishing curvature condition associated with the U(1) group and

J. Hietarinta

In this letter we present constant solutions to the tetrahedron equations proposed by Zamolodchikov. In general, from a given solution of the Yang-Baxter equation there are two ways to construct solutions to the tetrahedron equation. There are also other kinds of solutions. We present some two-dimensional solutions that were obtained by directly solving the

Lawrence M. Krauss

I review recent developments in cosmology and astrophysics relevant to particle physics, focussing on the following questions: What's new in 1992? What have we learned since the last ICHEP meeting in 1990? and What are the prospects for the future? AMong the topics explicitly discussed are: COBE, Large Scale Structure, and Dark Matter; Bib Bang Nucleosyn

The MILC Collaboration, C. Bernard, T. A. DeGrand, C. DeTar

We have continued our study of finite size effects in the QCD spectrum on lattices ranging in size from $8^3\times 24$ to $16^3\times24$. We have increased our statistics for quark mass $am_q=0.025$ for the smallest lattice size. In addition, we have studied quark mass 0.0125 for lattice sizes $12^3\times24$ and $16^3\times24$. These lattice sizes correspond

J. B. Bronzan, Timothy E. Vaughan

We study the gauge fixing of lattice QCD in 2+1 dimensions, in the Hamiltonian formulation. The technique easily generalizes to other theories and dimensions. The Hamiltonian is rewritten in terms of variables which are gauge invariant except under a single global transformation. This paper extends previous work, involving only pure gauge theories, to includ

Leonard Parker, Jonathan Z. Simon

We consider the Einstein equation with first order (semiclassical) quantum corrections. Although the quantum corrections contain up to fourth order derivatives of the metric, the solutions which are physically relevant satisfy a reduced equations which contain derivatives no higher than second order. We obtain the reduced equations for a range of stress-ener

Jan von Delft, Christopher L. Henley

The collective tunneling of a small cluster of spins between two degenerate ground state configurations of the Kagomé-lattice quantum Heisenberg antiferromagnet is \mbox{studied}. The cluster consists of the six spins on a hexagon of the lattice. The resulting tunnel splitting energy $Δ$ is calculated in detail, including the prefactor to the exponential $\e

Fabian H. L. Essler, Vladimir E. Korepin, Kareljan Schoutens

We study a superconducting integrable model of strongly correlated electrons in 1+1 dimensions. We construct all six Bethe Ansätze for the model and give explicit expressions for lowest conservation laws. We also prove a lowest weight theorem for the Bethe-Ansatz states.

J. I. Katz

Self-consistent models of gamma-ray burst source regions at 100 Kpc distance are possible if the radiating plasma is confined to very thin sheets, and I estimate parameters. Energy sources might be elastic (by starquakes) or magnetic (by reconnection), but mechanisms remain obscure. I discuss a very speculative model involving collisions between comets in a

UKQCD Collaboration

From an accurate determination of the inter-quark potential, one can study the running coupling constant for a range of $R$-values and hence estimate the scale $\Lambda_{\overline{\rm MS}}$. Detailed results are presented for $SU(3)$ pure gauge theory from a study of a $36^4$ lattice at $\beta=6.5$. (to appear in Proceedings of Lattice 1992 - Amsterdam)

UKQCD collaboration

We have calculated the $q\bar q$ potential over a wide range of lattice separations on a $48^3\cdot56$ lattice at $\beta = 2.85$. We are able to investigate both long-range and (by correcting for the effects of lack of rotational invariance) short-range potentials. From the former we estimate the string tension and from the latter we are able to investigate

Brian R. Greene, Samir D. Mathur, Christopher M. O'Neill

We study regular and black hole solutions to the coupled classical Einstein--Yang-Mills--Higgs system. It has long been thought that black hole solutions in the spontaneously broken phase of such a theory could have no nontrivial field structure outside of the horizon. We first show that the standard black hole no-hair theorem underlying this belief, althoug

Jens UH Petersen

A new 2-parameter quadratic deformation of the quantum oscillator algebra and its 1-parameter deformed Heisenberg subalgebra are considered. An infinite dimensional Fock module representation is presented which at roots of unity contains null vectors and so is reducible to a finite dimensional representation. The cyclic, nilpotent and unitary representations

H. Dreiner, G. K. Leontaris, N. D. Tracas

We extend a fermion mass matrix Ansatz by Giuduce to include neutrino masses. The previous predictions are maintained. With two additional parameters, a large Majorana neutrino mass and a hierarchy factor, we have seven {\it further} low energy predictions: the masses of the neutrinos, the mixing angles and the phase in the leptonic sector. We choose a reaso

P. Gonzalez, V. Vento

The structure functions calculated in the Chiral bag model reproduce quite well, after appropriate perturbative evolution to large energy scales, the experimental data. We use these results to interpret the structure of the $EMC$ data as a quenching of the pion decay constant due to the in medium behavior of the nucleon. This explanation supports recent prop

Nigel J. Kalton, Sik-Chung Tam

We extend Pisier's abstract version of Grothendieck's theorem to general non-locally convex quasi-Banach spaces. We also prove a related result on factoring operators through a Banach space and apply our results to the study of vector-valued inequalities for Sidon sets. We also develop the local theory of (non-locally convex) spaces with duals of wea

M. J. Martins

We review recent progresses in the study of factorized resonance scattering S-matrices. The resonance amplitudes are introduced through a suitable analytical continuation of the ADE Toda S-matrices. By using the thermodynamic Bethe ansatz approach we are able to compute the ground state energy, which describes a rich pattern of flows interpolating between th

E. Elizalde, S. D. Odintsov

The conformal anomaly induced sector of four-dimensional quantum gravity (infrared quantum gravity) ---which has been introduced by Antoniadis and Mottola--- is here studied on a curved fiducial background. The one-loop effective potential for the effective conformal factor theory is calculated with accuracy, including terms linear in the curvature. It is pr

U. Bruzzo, J. A. Dominguez Perez

A relative Picard theory in the context of graded manifolds is introduced. A Berezinian calculus and a theory of connections over SUSY-curves are systematically developed, and used to prove a Gauss-Bonnet theorem for line bundles in that setting and to discuss the validity of a flatness theorem

U. Bruzzo, J. A. Dominguez Perez

A first step towards a systematic theory of relative line bundles over SUSY-curves is presented. In this paper we deal with the case of relative line bundles over families of ordinary Riemann surfaces. Generalizations of the Gauss-Bonnet theorem and of the flatness theorem for line bundles are discussed.

Junegone Chay, Deog Ki Hong, Taejin Lee, S. H. Park

We investigate the effects of the Chern-Simons coupling on the high energy behavior in the $(2+1)$-dimensional Chern-Simons QED with a four-Fermi interaction. Using the $1/N$ expansion we discuss the Chern-Simons effects on the critical four-Fermi coupling at $O(1/N)$ and the $β$ function around it. High-energy behavior of Green's functions is also discu

Fernando Falceto, Krzysztof Gawedzki

We present a rigorous analysis of the Schrödinger picture quantization for the $SU(2)$ Chern-Simons theory on 3-manifold torus$\times$line, with insertions of Wilson lines. The quantum states, defined as gauge covariant holomorphic functionals of smooth $su(2)$-connections on the torus, are expressed by degree $2k$ theta-functions satisfying additional condi

Toshiki Isse

Dynamics of quantized free fields ( of spin 0 and 1/2 ) contained in a subspace $V_*$ of an N+4 dimensional flat space $V$ is studied. The space $V_*$ is considered as a neighborhood of a four dimensional submanifold $M$ arbitrarily embedded into $V$. We study the system as a simple model of unified theory of gravity ($g$), SO(N) gauge fields ($A$) and Higgs

Rolf Schimmrigk

A recently introduced framework for the compactification of supersymmetric string theory involving noncritical manifolds of complex dimension $2k+D_{crit}$, $k\geq 1$, is reviewed. These higher dimensional manifolds are spaces with quantized positive Ricci curvature and therefore do not, a priori, describe consistent string vacua. It is nevertheless possible

M. Rafecas, V. Vento

Using the positivity of the path integral measure of $QCD$ and defining a structure for the quark propagator in a background field according to the fluxon scenario for confinement, we calculate and compare the correlators for nucleon and delta. From their shape we elucidate about the origin of their mass difference, which in our simplified scenario is due to

A. Ferrando, V. Vento

In the bosonized version of two dimensional theories non trivial boundary conditions (topology) play a crucial role. They are inevitable if one wants to describe non singlet states. In abelian bosonization, color is the charge of a topological current in terms of a non-linear meson field. We show that confinement appears as the dynamical collapse of the topo

A. Ferrando, V. Vento

Two dimensional massless Quantum Chromodynamics presents many features which resemble those of the true theory. In particular the spectrum consists of mesons and baryons arranged in flavor multiplets without parity doubling. We analyze the implications of chiral symmetry, which is not spontaneously broken in two dimensions, in the spectrum and in the quark c

Chung-Pei Ma

SO(10) cosmic strings formed during the phase transition Spin(10) $\rightarrow$ SU(5) $\times{\cal Z}_2$ are studied. Two types of strings --- one effectively Abelian and one non-Abelian --- are constructed and the string solutions are calculated numerically. The non-Abelian string can catalyze baryon number violation via the ``twisting'' of the scal

Heinz König

We present the results of the contributions to the decay rate of the lightest Higgs particle into a charm-anticharm and bottom-antibottom pair within the minimal supersymmetric standard model when scalar quarks and a gluino are taken within the relevant loop diagrams. We show that in the case where the vacuum expectation values of the Higgs particles obey th

Jon Butterworth, Herbert Dreiner

We summarize the signals at HERA in supersymmetric models with explicitly broken R-parity. As the most promising case, we consider in detail the resonant production of single squarks through an operator $L_1Q_i{ \bar D}_j$, a production process analogous to that for leptoquarks. However, the dominant decay of the squark to a quark and a photino leads to a ve

Herbert Dreiner

In this talk given at the TAU92 Workshop, Columbus, OH, Sept. 92, we summarize results presented in more detail in a recent paper by S. Abel, M. Dittmar and the author where we gave a general proof that Bell's inequality can not be tested at a collider experiment. In particular, a measurement of correlated tau-spins at LEP does not constitute a test of l

Bo-Qiang Ma, Andereas Schaefer, Walter Greiner

The Gottfried sum rule violation reported by the New Muon Collaboration(NMC) was interpreted as indication for a flavour asymmetry of the sea quark in the nucleons. We investigate the alternative possibility that isospin symmetry between the proton and the neutron is breaking. We examine systematically the consequences of this possibility for several process

Leszek Roszkowski

A recent discovery by the COBE satellite is presented, and its importance discussed in the context of the physics of the early Universe. The various implications for our understanding of the structure of the Universe are outlined.

Stephen Sharpe

In the quenched approximation, loops of the light singlet meson (the $η'$) give rise to a type of chiral logarithm absent in full QCD. These logarithms are singular in the chiral limit throwing doubt upon the utility of the quenched approximation. In previous work, I summed a class of diagrams, leading to non-analytic power dependencies such as $\cond\pr

Sourendu Gupta

In quenched QCD, on lattices with $\nt=4$, the absence of a pole in the pseudoscalar meson channel for $T>T_c$ is demonstrated. A set of effective 4-fermi couplings is extracted. It is observed that this coupling is small in the vector channel for all $T>T_c$, but not in the pseudoscalar channel. The temperature dependence of hadronic parameters below \tc{}

K. M. Bitar

We present results from simulations of lattice QCD using two flavors of dynamical Wilson fermions at a lattice coupling $β=5.3$ on $16^3 \times 32$ lattices at two hopping parameters, $κ=0.1670$ and $0.1675$, leading to $m_π\approx 0.44$ and $0.33$ respectively. We show spectroscopy for S-wave hadrons and compare our results to other recent simulations with

Greg Kuperberg

Let $K$ be an $n$-dimensional symmetric convex body with $n \ge 4$ and let $K\dual$ be its polar body. We present an elementary proof of the fact that $$(\Vol K)(\Vol K\dual)\ge \frac{b_n^2}{(\log_2 n)^n},$$ where $b_n$ is the volume of the Euclidean ball of radius 1. The inequality is asymptotically weaker than the estimate of Bourgain and Milman, which rep