1212.4570 (Krzysztof Gawryluk et al.)

Mott-insulator phases at half-integer fillings in the imbalanced
honeycomb lattice    [PDF]

Krzysztof Gawryluk, Christian Miniatura, Benoît Grémaud

We investigate the ground state properties, using an improved Gutzwiller-like ansatz, of ultracold bosons loaded in a honeycomb lattice, with on-site repulsive interaction. In the situation of imbalanced hopping amplitudes, we have found half-integer Mott-insulator phases, i.e. states with half-integer filling and vanishing compressibility, arising due to the interplay between the quantum correlations and the topology of the honeycomb lattice. These new phases have unambiguous signatures in the velocity distribution, and thus could be easily observed experimentally.

View original: http://arxiv.org/abs/1212.4570