Quarter-filled Kitaev-Hubbard Model: A Quantum Hall State in an Optical   Lattice
  We analyze the Physics of cold atoms in honeycomb optical lattices with on-site repulsion and spin-orbit couplings that break time reversal symmetry. Such systems, at half filling and large on-site repulsion, have been proposed as a possible realization of the Kitaev model. The spin-orbit couplings break the spin degeneracy and, if strong-enough, lead to four non-overlapping bands in the non-interacting limit. These bands carry non-zero Chern number and therefore the non-interacting system has non-zero angular momentum and chiral edge states at 1/4 and 3/4 filling. We have investigated the effect of interactions using the variational cluster perturbation theory and conclude that the chiral edge states exist in finite range of interaction and hopping parameter space. 
S. R. Hassan, Sandeep K Goyal, R. Shankar, and David S\'en\'echal
cond-mat.str-el quant-ph