Stability of p-orbital Bose-Einstein condensates in optical checkerboard and square lattices

摘要

We investigate p-orbital Bose-Einstein condensates in both the square and checkerboard lattice by numericallynsolving the Gross-Pitaevskii equation. The periodic potential for the latter lattice is taken exactly from thenrecent experiment [Nature Phys. 7, 147 (2011)]. It is confirmed that the staggered orbital-current state is thenlowest-energy state in the p band. Our numerical calculation further reveals that for both lattices the staggerednp-orbital state suffers Landau instability but the situation is remarkably different for dynamical instability. Andynamically stable parameter region is found for the checkerboard lattice, but not for the square.