Strongly interacting bosons in a 1D optical lattice at incommensurate   densities
  We investigate quantum phase transitions occurring in a system of strongly interacting ultracold bosons in a 1D optical lattice. After discussing the commensurate-incommensurate transition, we focus on the phases appearing at incommensurate filling. We find a rich phase diagram, with superfluid, supersolid and solid (kink-lattice) phases. Supersolids generally appear in theoretical studies of systems with long-range interactions; our results break this paradigm and show that they may also emerge in models including only short-range (contact) interactions, provided that quantum fluctuations are properly taken into account. 
Achilleas Lazarides, Olivier Tieleman, Cristiane Morais Smith
cond-mat.quant-gas