Abstract
A new method to simulate lattice systems is described. We demonstrate our method by computing the complete partition functions of Z(2) and Z(8) gauge theories in four dimensions on lattices of size up to 6
4. Our method yields a clear signal for the first order transition(s) in these models without hysteresis or critical slowing down effects. We show how finite size scaling of the zeros of the partition function provides an unambiguous identification of the order of the transition.