Dynamical instability and loss of p-band bosons in optical lattices

We study how the bosonic atoms on the excited p band of an optical lattice are coupled to the lowest s band and the second excited d band. We find that in some parameter regimes, the atom-atom interactions can cause a dynamical instability of the p-band atoms toward decay to the s and d bands. Furthermore, even when dynamical instability is not expected s and d bands can become substantially populated. We also find that the stability properties of the excited bands can be improved in superlattices.