Purification of superposed coherent states via partial homodyne detection
Shigenari Suzuki, Masahiro Takeoka, Masahide Sasaki, Ulrik L. Andersen, Fumihiko Kannari · arXiv (Cornell University) · 2005
We present a simple protocol to purify a coherent state superposition from a statistical mixture of a superposed states and coherent states. The scheme constitutes only a single beam splitter and a homodyne detector, and thus experimentally feasible. In practice, a superposition of coherent states is transformed into such a mixture 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.