Monopoles and Chaos

We decompose U(1) gauge fields into a monopole and photon part across the phase transition from the confinement to the Coulomb phase. We analyze the leading Lyapunov exponents of such gauge field configurations on the lattice which are initialized by quantum Monte Carlo simulations. It turns out that there is a strong relation between the sizes of the monopole density and the Lyapunov exponent.Comment: Contribution to HEP-MAD'01 - High-Energy Physics International Conferences (Antananarivo, Madagascar, 2001/09/27 - 2001/10/05), 6 pages, 5 figure

Baryon-Baryon Potentials on the Lattice

The interaction of spatially extended heavy baryons is investigated in the framework of lattice QCD with dynamical quarks. It is shown that the expected dipole forces have a very short range and that the baryon-antibaryon interaction is more attractive than the baryon-baryon interaction. Sea quarks play a minor important role.Comment: 8 pages, uuencoded postscript file; Physics Letters B, in pres

Chiral condensate, quark charge and chiral density

We study the topological and fermionic vacuum structure of four-dimensional QCD on the lattice by means of correlators of fermionic observables and topological densities. We show the existence of strong local correlations between the topological charge density and the quark condensate, charge and chiral density. By analysis of individual gauge configurations, we visualize that instantons (antiinstantons) carry positive (negative) chirality, whereas the quark charge density fluctuates in sign within instantons.Comment: LATTICE98(confine), 3 pages, 2 figure

Chirality tubes along monopole trajectories

We classify the lattice by elementary 3-cubes which are associated to dual links occupied by, or free of monopoles. We then compute the quark condensate, the quark charge and the chiral density on those cubes. By looking at distributions we demonstrate that monopole trajectories carry considerably more chirality with respect to the free vacuum.Comment: LATTICE99(topology), 3 pages, eps figure

Towards a Topological Mechanism of Quark Confinement

We report on new analyses of the topological and chiral vacuum structure of four-dimensional QCD on the lattice. Correlation functions as well as visualization of monopole currents in the maximally Abelian gauge emphasize their topological origin and gauge invariant characterization. The (anti)selfdual character of strong vacuum fluctuations is reveiled by smoothing. In full QCD, (anti)instanton positions are also centers of the local chiral condensate and quark charge density. Most results turn out generically independent of the action and the cooling/smoothing method.Comment: 14 pages, Contribution to YKIS9

Meson-meson interactions -- from static to dynamic valence quarks

A method for the extraction of an effective meson-meson potential from Green functions, which can be obtained from a lattice simulation, is presented. Simulations are carried out for compact QED and QCD in four dimensions using the quenched approximation and the hopping parameter expansion. In a further study, a heavy-light meson is considered employing a conjugate gradient algorithm for the light propagators. Due to the Pauli exclusion principle, the results for QED indicate the existence of a hard core, but for QCD there is strong attraction at small meson distances.Comment: 4 pages, uuencoded gziped postscript file, contribution to LATTICE'95, Melbourne, Australia (list of authors completed

Topological charge density around static colour sources in lattice QCD with dynamical quarks

We update our numerical investigation of topological structures around static quarks in pure gauge QCD by results of the first runs including dynamical quarks. Simulations were performed on an $8^3\times4$ lattice, with $SU(3)$ Wilson action, with 3 flavours of quarks of equal mass, both in the confinement and deconfinement phase. In the confinement phase we observe indications for the existence of a flux tube between a static quark and antiquark, flux-tube breaking for large separations, and local correlation between the topological charge density and chiral condensate. In the deconfinement phase almost all configurations turn out to be topologically trivial.Comment: 3 pages, PostScript, uuencoded and compressed tar file (Contribution to LATTICE 94 in Bielefeld.

Monopole density around static color sources

We analyze the vacuum structure with respect to magnetic monopoles of quenched QCD in the presence of static color sources. Distributions of the monopole density around static quarks and mesons are computed in both phases of QCD. We observe a suppression of the monopole density in the vicinity of external sources. In the confinement phase the density of color magnetic monopoles is reduced along the flux tube between a static quark-antiquark pair.Comment: 3 pages, uuencoded postscriptfile (690kB), Contribution to the XII INTERNATIONAL SYMPOSIUM ON LATTICE FIELD THEORY, Bielefeld, Germany, 199