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

Zero-momentum modes and chiral limit in compact lattice QED

The influence of zero-momentum gauge modes on physical observables is investigated for compact lattice QED with dynamical and quenched Wilson fermions. Within the Coulomb phase, zero-momentum modes are shown to hide the critical behaviour of gauge invariant fermion observables near the chiral limit. Methods for eliminating zero-momentum modes are discussed.Comment: Talk at Lattice 2000, Bangalore, 4 pages, 3 figures, LaTe

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

Gluon propagator and zero-momentum modes on the lattice

We investigate the propagators of 4D SU(2) gauge theory in Landau gauge by Monte Carlo simulations. To be able to compare with perturbative calculations we use large $\beta$ values. There the breaking of the Z(2) symmetry causes large effects for all four lattice directions and doing the analysis in the appropriate state gets important. We find that the gluon propagator in the weak-coupling limit is strongly affected by zero-momentum modes.Comment: 3 pages, LaTeX, 5 figures, uses espcrc2.sty and epsfig.sty. Contribution to Lattice'9