Frustration of a Bose gas inside an optical lattice

Under suitable conditions, the Hamiltonian of a gas of cold bosonic atoms inside a rotating optical
lattice can be mapped onto that of a frustrated Bose-Hubbard model. Here, the role of magnetic frustration is
played by the angular frequency of rotation of the lattice. The system can be fully frustrated at experimentally
attainable values of the frequency of rotation, and a superlattice of vortices appears in the ground state. This has
several implications on observable quantities such as the superfluid density and the momentum distribution
function. In the limit of large on-site occupation and in dimensionality D >= 2, the system can be mapped into an array of Josephson junctions in a magnetic field.