QUANTUM FLUCTUATIONS VERSUS TOPOLOGY - A STUDY IN U(1)(2) LATTICE GAUGE-THEORY

Using the geometric definition of the topological charge we decompose the path integral of 2-dimensional U(1) lattice gauge theory into topo logical sectors, In a Monte Carlo simulation we compute the average va lue of the action as well as the distribution of its values for each s ector separately. These numbers are compared with analytic lower bound s of the action which are relevant for classical configurations carryi ng topological charge. We find that quantum fluctuations entirely domi nate the path integral. Our results for the probability distribution o f the Monte Carlo generated configurations among the topological secto rs can be understood by a semi-phenomenological argument. (C) 1997 Pub lished by Elsevier Science B.V.