Phase-Controlled Atom-Photon Entanglement in a Three-Level lambda-Type   Closed-Loop Atomic System
  The atom-photon entanglement is studied in a three-level lambda-type closed-loop atomic system in multi-photon resonance condition and beyond it. It is shown that the von Neumann entropy in such a system is phase dependent, and it can be controlled by either intensity or relative phase of applied fields. It is demonstrated that for the special case of Rabi frequency of applied fields, the system is disentangled. 
Ali Mortezapour, Zeinab Kordi, and Mohammad Mahmoudi
physics.atm-clus quant-ph