Steady Fock states via atomic reservoir
  In this letter we present a strategy that combines the action of cavity damping mechanisms with that of an engineered atomic reservoir to drive an initial thermal distribution to a Fock equilibrium state. The same technique can be used to slice probability distributions in the Fock space, thus allowing the preparation of a variety of nonclassical equilibrium states. 
F. O. Prado, W. Rosado, G. D. de Moraes Neto, and M. H. Y. Moussa
quant-ph