University of Stuttgart
Recently, several different of heteronuclear polar molecules have been successfully cooled down to the ultra-cold regime, in some cases accessing the ro-vibrational ground state. Theoretical proposals have been put forward, that under appropriately tuned electric and mircowave fields, such ultra-cold polar molecules can exhibit strong three-body interactions of similar size as the usually dominating two-body terms. When confined to low-dimensional optical lattices, such systems form strong-coupling realizations of a extended Hubbard-models, dominated by the appearance of strong extended three-body repulsion terms. Here, we use quantum Monte Carlo simulations to study the properties of such ultra-cold polar molecules in different lattice geometries. For the minimum model in a one-dimensional setup, we establish the presence of a new insulating phase at a lattice filling of 2/3, where the systems shows a coexistence of a density wave and bond order. We present preliminary results obtained for a honeycomb lattice geometry, that exhibit the emergence of various valence bond crystal phases with local resonances driven by the kinetic energy.