We propose and analyse a scheme to cool atoms in an optical lattice to ultra-low temperatures within a Bloch band, and away from commensurate filling. The protocol is inspired by ideas from dark state laser cooling, but replaces electronic states with motional levels, and spontaneous emission of photons by emission of photons into a Bose-Einstein condensate, in which the lattice is immersed. In ourmodel, achievable temperatures correspond to a small fraction of the Bloch band width, and are much lower than the reservoir temperature. This is also a novel realization of an open quantum optical system, where known tools are combined with new ideas involving cooling via a reservoir.
10 Minute Talk: Cryogenic planar ion traps