Currents, chemical potential and boundary conditions in lattice QCD

A connection between the operator fermionic currents \hatJ and corresponding `Grassmannian' currents $J$ in the functional integral formalism is studied. The QCD action with non--zero chemical potential $\mu$ is derived. A connection between the fermionic Fock space and boundary conditions along the forth direction is discussed.Comment: Lattice2002 (spectrum

Classical solutions in lattice gauge theories

The solutions of the classical equations of motion on a periodic lattice are found which correspond to abelian single and double Dirac sheets. These solutions exist also in non--abelian theories. Possible applications of these solutions to the calculation of gauge dependent and gauge invariant observables are discussed.Comment: 13 pages, Latex file including four figure

Disorder parameter and canonical quantization approach in lattice gauge theory

The work is dedicated to the derivation of the 'functional' integral representation of the disorder parameter. This derivation resolves the problem of the choice of the so called modifed action as well as the problem of the choice of the boundary conditions along the 'time' direction. The question of the gauge fixing in the functional integral representation is also discussed.Comment: 8 pages. Revised version because of the minor LATEX error. Revised version : additional references adde

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