Putting competing orders in their place near the Mott transition
Putting competing orders in their place near the Mott transition
We describe the localization transition of superfluids on two-dimensional lattices into commensurate Mott insulators with average particle density $p∕q$ ($p,q$ relatively prime integers) per lattice site. For bosons on the square lattice, we argue that the superfluid has at least $q$ degenerate species of vortices which transform under a projective …