CLUSTER MONTE-CARLO STUDY OF THE QUANTUM XY MODEL IN 2 DIMENSIONS

The recent generalization of the Fortuin-Kasteleyn percolation represe ntation and the Swendsen-Wang (SW) cluster algorithm is reviewed. The new representation yields cluster algorithm for the XYZ model with arb itrary magnitude of spins, with arbitrary anisotropies, and in any dim ensions. The new algorithm often reduces computational autocorrelation times by several orders of magnitude. By using the new algorithm toge ther with methods of Bayesian statistical inference, we obtained the d ynamical structure factor S(k, w) for the S = 1/2 XY model in two dime nsions.