Topical Results on Lattice Chiral Fermions in the CFA

We report new results on the lattice regularization of the chiral Schwinger model and the chiral U(1) model in four dimensions in the CFA.Comment: LATTICE98(chiral

Interplay of Monopoles and P-Vortices

We show that P-Vortices in the confinement phase of SU(2) lattice gauge theory form one large percolating (infrared) cluster and a number of small (ultraviolet) clusters. We discuss the interrelation of clusters of monopoles in the maximal Abelian projection with clusters of P-vortices. To extract P-vortices we use both direct and indirect central projections and find qualitatively similar results.Comment: 3 pages, 4 figures; talk given at Lattice 2003 (Tsukuba, Japan

Flux Tubes of Two- and Three-Quark System in Full QCD

We study the abelian color flux of two- and three-quark systems in the maximally abelian gauge in lattice QCD with dynamical fermions. We find that the abelian flux tube formed between quark and antiquark is very much the same as in quenched QCD up to quark separations of $R$$\sim$ 2fm. The profile of the color electric field in three-quark system suggests $Y$ ansatz, which might be interpreted as the result of the vacuum pressure in the confined phase. In order to clarify the flux structure, we investigate the color electric field of the three-quark system splittting the abelian gauge field into the monopole and photon parts.Comment: 4 pages, 4 figures, Talk given at XVI International Conference on Particles and Nuclei (PaNic02),Osaka, Japan, Sep.30 - Oct.4, 200

Geometry of percolating monopole clusters

We perform detailed measurements of the geometrical characteristics of the percolating cluster of the magnetic monopole currents in the confining phase of the lattice SU(2) gluodynamics. The Maximal Abelian projection is used to define the monopoles. The use of the geometrical language is motivated by recent observations that the full non-Abelian action associated with the monopoles corresponds to point-like particles on the currently available lattices. Scaling behavior of various quantities is observed.Comment: 3 pages, 4 figures, Lattice2002(topology

The flux distribution of the three quark system in SU(3)

We study the abelian color-flux distribution of the three quark system in the maximally abelian gauge on SU(3) lattices. The distribution of the color electric field suggests $Y Ansatz$, which might be interpreted through the dual superconductor picture as the result of the vacuum pressure in the confined phase. In order to clarify the flux structure, we investigate the color electric field in the three quark system also in the monopole part and in the photon part.Comment: 3pages, 5figures, Lattice2002(topology

Compact Lattice QED with Staggered Fermions and Chiral Symmetry Breaking

Different formulations of the $4d$ compact lattice QED with staggered fermions (standard Wilson and modified by suppression of lattice artifacts) are investigated by Monte Carlo simulations within the quenched approximation. We show that after suppressing lattice artifacts the system undergoes a phase transition from the Coulomb phase into a presumably weakly chirally broken phase only at (unphysical) negative $\beta$--values.Comment: 7 pages, 5 figures attached in compressed postscript files, preprint DESY-IfH and HU Berlin-IEP-94/11, submitted to Phys. Lett.

Monopoles in Compact U(1) -- Anatomy of the Phase Transition

We present evidence that the existence of a first order phase transition in compact U(1) with Wilson action is not related to monopole loops wrapping around the toroidal lattice, as has been previously suggested. Our analysis is based on the suppression of such loops by `soft boundary conditions' that correspond to an infinitely large chemical potential for the monopoles on the boundary, during the updating process. It is observed that the double peak structure characteristic for the first order phase transition reappears at sufficiently large lattice sizes and separations from the lattice boundary.Comment: 8 pages, (color) ps-figures available via anonymous ftp at ftp://wpts0.physik.uni-wuppertal.de/pub/monopoles/figures.u

Lattice QCD gluon propagators near transition temperature

Landau gauge gluon propagators are studied numerically in the SU(3) gluodynamics as well as in the full QCD with the number of flavors $n_F=2$ using efficient gauge fixing technique. We compare these propagators at temperatures very close to the transition point in two phases : confinement and deconfinement. The electric mass $m_E$ has been determined from the momentum space longitudinal gluon propagator. Gribov copy effects are found to be rather strong in the gluodynamics, while in the full QCD case they are weak ("Gribov noise"). Also we analyse finite volume dependence of the transverse and longitudinal propagators.Comment: 9 pages, 7 figure

Center Dominance Recovered: Direct Laplacian Center Gauge

We introduce a variation of direct maximal center gauge fixing: the "direct Laplacian" center gauge. The new procedure consists of first fixing to the Laplacian adjoint Landau gauge, followed by overrelaxation to the nearby Gribov copy of the direct maximal center gauge. Certain shortcomings of maximal center gauge, associated with Gribov copies, are overcome in the new gauge, in particular center dominance is recovered.Comment: 3 pages, 2 EPS figures, Lattice2001(confinement