We study the surface and the reflection cluster algorithms, which have been developed for systems with global continuous symmetries by Niedermayer and Wolff, respectively, in the O(4) spin model in four dimensions. The surface algorithm appears not to be substantially better than local algorithms for this model. We show that the reflection algorithm has big advantages: It fights critical slowing down and due to the use of improved estimators it gives a variance reduction.

• Received 14 June 1989

DOI:https://doi.org/10.1103/PhysRevLett.63.2613