Proposal to produce long-lived mesoscopic superpositions through an   atom-driven field interaction
  We present a proposal for the production of longer-lived mesoscopic superpositions which relies on two requirements: parametric amplification and squeezed vacuum reservoir for cavity-field states. Our proposal involves the interaction of a two-level atom with a cavity field which is simultaneously subjected to amplification processes. 
C. J. Villas-Boas, F. R. de Paula, R. M. Serra, and M. H. Y. Moussa