多模光场与二能级原子相互作用系统中保真度与纠缠度的关联

Relevance Between Fidelity and Degree of Entanglement in the System of Two-level Atoms Interacting with Multi-mode Fields

利用全量子理论及数值计算方法,计算了由M个二能级原子和M个多模腔场构成的联合系统原子保真度和原子纠缠度,数值计算及分析表明:如果初始原子处于分离态,那么原子保真度与原子纠缠度始终存在相互反相的振荡现象,随着光场强度的增加,二者的振荡均会越来越频繁;在光场与原子强耦合的情况下,原子保真度更多趋于0、原子纠缠度更多趋于1;保真度较小不利于信息传输,但通过适当控制相互作用时间,可达到高保真度原子信息传输的目的.

The atom fidelity and degree of entanglement were calculated in the system consisting of M two-level atoms and M multi-mode fields by use of complete quantum theory and number computing method. Through number computing and analyzing, it was found that the atom fidelity and the atom entangled degree present always oscillatory with opposite in phase if initial atoms are in separate state, and both of their frequency gradually increase with the intensity of light field increasing. The atom fidelity tends to 0 and degree of entanglement tends to 1 under strongly coupling between atoms and light fields. The small fidelity is disadvantage of information transfer but high-fidelity atom information transfer can still obtained by controlling appropriately interaction time.