利用两能级原子与相干态腔场相互作用实现纠缠浓缩

Concentrating entanglement via two-level atom interacting with the coherent state of cavity fields

根据大失谐条件下原子–腔场相互作用的特点,讨论了一个制备纠缠相干态的方法,提出了一个利用两能级原子与腔场相干态相互作用实现纠缠浓缩的方案。在这个方案中,2个具有相同振幅但有着π相位差的相干光|α〉和|-α〉构成的纠缠态光场被用来作为量子信道,通过利用两能级原子与腔场的相互作用以及两模正交态测量实现了这个纠缠浓缩的过程。结果表明:对于纠缠相干态,无论其初始的纠缠是多么微弱,利用这种方法总有一定的几率可以从部分纠缠态中提取出最大纠缠态。

Based on the dispersive atom-cavity field interaction, the scheme for preparing the entangled coherent state is discussed. An experimentally feasible protocol for realizing entanglement concentration of the entangled coherent states via using a two-level atom interacting with caving fields is proposed. In this protocol, the entanglement between two coherent states, ｜α） and ｜α）, with the same amplitude but a phase difference π is utilized as the quantum channel. The process of the entanglement concentration is implemented by using a two-level atom interacting with caving fields and two-modes orthogonal states measurement. It is explained that, no matter how small the initial entanglement is, to distill some maximally entangled states from the initial partially entangled pure states is possible.