CRITICAL-BEHAVIOR OF THE 3D XY-MODEL - A MONTE-CARLO STUDY

We present the results of a study of the three-dimensional XY-model on a simple cubic lattice using the single cluster updating algorithm co mbined with improved estimators. We have measured the susceptibility a nd the correlation length for various couplings in the high temperatur e phase on lattices of size up to L = 112. At the transition temperatu re we studied the fourth-order cumulant and other cumulant-like quanti ties on lattices of size up to L = 64. From our numerical data we obta in for the critical coupling K(c) = 0.45420(2) and for the static crit ical exponents gamma/nu = 1.976(6) and nu = 0.662(7).