Spin-Liquid Behavior of a Simple Spin Model on the Triangular Lattice

I will report on numerical studies of phase transition between competing magnetic (M) and valence bond solid states (VBS) using unbiased quantum Monte Carlo methods in sign-problem free models on non-bipartite lattices in two dimensions. On bipartite lattices the transition between these two phases is a direct second order critical point - consistent with various aspects of the ``deconfined'' criticality scenario. In contrast, on non-bipartite lattices an intermediate phase appears between M and VBS. We present evidence that this new phase is a quantum spin liquid.