Beyond mean-field study of a binary bosonic mixture in a state-dependent   honeycomb lattice
  We investigate a binary mixture of bosonic atoms loaded into a state-dependent honeycomb lattice. For this system, the emergence of a so-called twisted-superfluid ground state was experimentally observed in [Soltan-Panahi et al., Nat. Phys. 8, 71 (2012)]. Theoretically, the origin of this effect is not understood. We perform numerical simulations of an extended Bose-Hubbard model adapted to the experimental parameters employing the Multi-Layer Multi-Configuration Time-Dependent Hartree method for Bosons. Our results confirm the overall applicability of mean-field theory within the relevant parameter range. Beyond this, we provide a detailed analysis of correlation effects correcting the mean-field result. These have the potential to induce asymmetries in single shot time-of-flight measurements, but we find no indication of the patterns characteristic of the twisted superfluid. We comment on the restrictions of our model and possible extensions. 
Lushuai Cao, Sven Kr\"onke, Jan Stockhofe, Peter Schmelcher, Juliette   Simonet, Klaus Sengstock, Dirk-S\"oren L\"uhmann
cond-mat.quant-gas quant-ph