Efficient atomic and photonic multipartite W state concentration via photonic faraday rotation

摘要: We propose entanglement concentration protocols for nonlocal W states using the Faraday rotation of photonic polarization. Through single-photon input-output process in cavity QED, it is shown that maximally entangled atomic (photonic) state can be extracted from partially state. The distinct feature our protocol we concentrate both and via rotation, thus they may useful long distant communication experiment. Furthermore, since works low-Q cavities only involves virtual excitation atoms, schemes are insensitive to decay spontaneous emission.