Loading of bosons in optical lattices into the p band

We present a method for transferring bosonic atoms residing on the lowest s band of an optical lattice to the first excited p bands. Our idea hinges on resonant tunneling between adjacent sites of accelerated lattices. The acceleration effectively shifts the quasibound energies on each site such that the system can be cast into a Wannier-Stark ladder problem. By adjusting the acceleration constant, a situation of resonant tunneling between the s and p bands is achievable. Within a mean-field model, considering 87Rb atoms, we demonstrate population transfer from the s to the p bands with around 95% efficiency. Nonlinear effects deriving from atom-atom interactions, as well as coupling of the quasibound Wannier-Stark states to the energy continuum, are considered.