摘要
Entanglement plays an important role in quantum information science, especially in quantum communications. Here we present an efficient entanglement concentration protocol(ECP) for nonlocal atom systems in the partially entangled W-class states, using the single-photon input-output process regarding low-Q cavity and linear optical elements. Compared with previously published ECPs for the concentration of non-maximally entangled atomic states, our protocol is much simpler and more efficient as it employs the Faraday rotation in cavity quantum electrodynamics(QED) and the parameter-splitting method. The Faraday rotation requires the cavity with low-Q factor and weak coupling to the atom, which makes the requirement for entanglement concentration much less stringent than the previous methods, and achievable with current cavity QED techniques. The parameter-splitting method resorts to linear-optical elements only. This ECP has high efficiency and fidelity in realistic experiments, and some imperfections during the experiment can be avoided efficiently with currently available techniques.
Entanglement plays an important role in quantum information science, especially in quantum communications. Here we present an efficient entanglement concentration protocol（ECP） for nonlocal atom systems in the partially entangled W-class states, using the single-photon input-output process regarding low-Q cavity and linear optical elements. Compared with previously published ECPs for the concentration of non-maximally entangled atomic states, our protocol is much simpler and more efficient as it employs the Faraday rotation in cavity quantum electrodynamics（QED） and the parameter-splitting method. The Faraday rotation requires the cavity with low-Q factor and weak coupling to the atom, which makes the requirement for entanglement concentration much less stringent than the previous methods, and achievable with current cavity QED techniques. The parameter-splitting method resorts to linear-optical elements only. This ECP has high efficiency and fidelity in realistic experiments, and some imperfections during the experiment can be avoided efficiently with currently available techniques.
作者
Cong Cao
Xi Chen
YuWen Duan
Ling Fan
Ru Zhang
TieJunWang
Chuan Wang
Cong Cao;Xi Chen;YuWen Duan;Ling Fan;Ru Zhang;TieJunWang;Chuan Wang(State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications;School of Ethnic Minority Education, Beijing University of Posts and Telecommunications;School of Science, Beijing University of Posts and Telecommunications)
基金
supported by the National Natural Science Foundation of China(Grant Nos.61471050,61377097,11404031 and 61571060)
the Fok Ying-Tong Education Foundation for Young Teachers in the Higher Education Institutions of China(Grant No.151063)
the Fundamental Research Funds for the Central Universities(Grant No.2015RC28)
the Fund of State Key Laboratory of Information Photonics and Optical Communications(Beijing University of Posts and Telecommunications)(Grant No.IPOC2015ZT05)
