Practical purification scheme for decohered coherent-state   superpositions via partial homodyne detection
  We present a simple protocol to purify a coherent-state superposition that has undergone a linear lossy channel. The scheme constitutes only a single beam splitter and a homodyne detector, and thus is experimentally feasible. In practice, a superposition of coherent states is transformed into a classical mixture of coherent states by linear loss, which is usually the dominant decoherence mechanism in optical systems. We also address the possibility of producing a larger amplitude superposition state from decohered states, and show that in most cases the decoherence of the states are amplified along with the amplitude. 
Shigenari Suzuki, Masahiro Takeoka, Masahide Sasaki, Ulrik L.   Andersen, and Fumihiko Kannari