Cooling by corralling: a route to ultra-low entropies in optical lattices

A major motivation for cold atom experiments is the search for quantum ground states such as antiferromagnets and d-wave superfluids. The primary obstacle to this task is the difficulty of cooling to sufficiently low temperatures. We propose a way to achieve very low temperatures and entropies ($\sim 0.03k_B$ per particle) by trapping fermions in a corral formed from another species of atoms. The Fermi system can then be used as a heat sink, or it can be adiabatically evolved into other desired states. In particular, we suggest methods for generating antiferromagnetism using this technique.