Abstract
We show that the dynamics of cold bosonic atoms in a two-dimensional square optical lattice produced by a bichromatic light-shift potential is described by a Bose-Hubbard model with an additional effective staggered magnetic field. In addition to the known uniform superfluid and Mott insulating phases, the zero-temperature phase diagram exhibits a novel kind of finite-momentum superfluid phase, characterized by a quantized staggered rotational flux. An extension for fermionic atoms leads to an anisotropic Dirac spectrum, which is relevant to graphene and high-Tc superconductors.
| Original language | Undefined/Unknown |
|---|---|
| Pages (from-to) | 1-4 |
| Number of pages | 4 |
| Journal | Physical Review Letters |
| Volume | 100 |
| Issue number | 130402 |
| Publication status | Published - 2008 |