Dynamical correlations of the Quantum Dimer Model on the triangular lattice

Using Green's function Monte Carlo simulations, we have studied the zero-temperature properties of the quantum dimer model (QDM)on the triangular lattice [1] on clusters with up to 588 sites. A detailed comparison of the static properties in different topological sectors as a function of the cluster size and for different cluster shapes has allowed us to identify different phases, and to to show explicitly the presence of topological degeneracy in a phase close to the Rokhsar-Kivelson point, in agreement with an earlier suggestion [2]. We have also extended the Green's function Monte Carlo algorithm to calculate dynamical correlation functions. Preliminary results on the dimer-dimer correlations confirm the extension of the RVB phase and bring new insight on the nature of the transition to the $\sqrt{12} \times \sqrt{12}$ phase and on the type of long-range order realized in that phase.\\ {[1]} A. Ralko, M. Ferrero, F. Becca, D. Ivanov and F. Mila, Phys. Rev. B, {\bf 71}, 224109 (2005).\\ {[2]} R. Moessner and S.L. Sondhi, Phys. Rev. Lett, {\bf 86}, 1881 (2001).