Abstract

I will discuss quantum Monte Carlo simulations algorithms for s=1/2 quantum spin systems formulated in the valence-bond basis, i.e., the basis of products of singlet pairs. This over-complete basis has some appealing features for studies of singlet ground states, and can be generalized to study triplet excitations as well. I will also show how one can combine valance bonds with loop updates of spin configurations, to further increase the efficiency of the simulations.