摘要
研究了无限维量子系统上保真度的问题.首先,利用量子保真度无限维版本的Uhlmann定理,获得了在无限维量子系统上关于量子保真度的强凹性、联合凹性和凹性等性质.其次,给出纠缠保真度与其量子态纯化选择无关的一个初等证明.最后,讨论了纠缠保真度与系综平均保真度之间的关系,得出系综平均保真度是纠缠保真度的一个上界.
The fidelity in the infinite-dimensional quantum systems was investigated.Firstly,based on the infinite-dimensional version of Uhlmann's theorem of fidelity,the properties of strong concavity,joint concavity and concavity of quantum fidelity in the infinite-dimensional quantum systems were obtained.Next,an elementary proof that the entanglement fidelity was independent on the choice of purification of the quantum state was given.Finally,the relationship between entanglement fidelity and ensemble average fidelity was discussed,it is concluded that ensemble average fidelity is an upper bound of entanglement fidelity.
引文
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