Frustrated quantum antiferromagnetism with ultracold bosons in a triangular lattice

We propose to realize the anisotropic triangular-lattice Bose-Hubbard model with positive tunneling matrix elements by using ultracold atoms in an optical lattice dressed by a fast lattice oscillation. This model exhibits frustrated antiferromagnetism at experimentally feasible temperatures; it interpolates between a classical rotor model for weak interaction, and a quantum spin-(1/2) XY-model in the limit of hard-core bosons. This allows to explore experimentally gapped spin-liquid phases predicted recently (Schmied R. et al., New J. Phys.,10 (2008) 045017). © 2010 Europhysics Letters Association.