GRIBOV AMBIGUITY AND NONTRIVIAL VACUUM-STRUCTURE OF GAUGE-THEORIES ON A CYLINDER

Using the hamiltonian framework, we analyze the Gribov problem for U (N) and SU (N) gauge theories on a cylinder ( = (1+1) dimensional spacetime with compact space S1). The space of gauge orbits is found to be an orbifold. We show by explicit construction that a proper treatment of the Gribov ambiguity leads to a highly non-trivial structure of all physical states in these quantum field theory models. The especially interesting example of massless QCD is discussed in more detail: There, some of the special static gauge transformations which are responsible for the Gribov ambiguity also lead to a spectral flow, and this implies a chiral condensate in all physical states. We also show that the latter is closely related to the Schwinger term and the chiral anomaly.