Dear all, Recently I use SSE QMC to perform a calculation of Bose-Hubbard model. The lattice I consider is basically a square lattice, but I use a plaquette containing four sites as a unit cell. I want to use structure factor to characterize possible CDW charge order. On normal square lattice, the momentum (\pi,\pi) can be chosen. However for the unit cell I chosen,how can I characterize the same CDW order? A similar case is Bose-Hubbard model on honeycomb lattice, what momentum is chosen for characterizing a CDW with staggered occupying the two inequivalent sites? Thank you very much! Sincerely, Huaiming Guo