Experimental implementation of heat-bath algorithmic cooling using   solid-state nuclear magnetic resonance
  We report here the experimental realization of multi-step cooling of a quantum system via heat-bath algorithmic cooling. The experiment was carried out using nuclear magnetic resonance (NMR) of a solid-state ensemble three-qubit system. 
Jonathan Baugh, Osama Moussa, Colm A. Ryan, Ashwin Nayak, Raymond   Laflamme