耗散腔中两二能级原子态的自旋压缩,量子Fisher信息和最大自旋涨落

在能量耗散腔中,原子用泡利算符描述,光场用相干态描述,运用密度矩阵理论,得到了两二能级原子密度矩阵元的演化规律,分析了与单模辐射场作用过程中原子态的自旋压缩、量子Fisher信息和最大自旋涨落.结果表明:自旋压缩,大于 的最大自旋涨落可以作为量子纠缠的充分必要判据.自旋压缩, 大于 的最大自旋涨落和量子纠缠,它们互相等价.大于1的Fisher信息与它们之间没有等价关系,但可以作为自旋压缩和量子纠缠的充分判据.

Spin squeezing, quantum Fisher information and maximal spin fluctuation of a pair atom with two-level in the dissipative cavity

we investigate the fidelity of several kinds of coherence states in the coordinate representation, and the analytic expression was given for coherence state, the relation between the fidelity and the character length and translation distance was discussed, and the influences of quantum interference of the initial state on the fidelity are discussed for superposition state of and .The results show that the fidelity evolved periodic; compared to fidelity of the coherence state, quantum interference can decrease the distortion of state when harmonic oscillator is in the second kind of coherence states, and quantum interference can decrease the distortion or increase the distortion when harmonic oscillator is in the third kind of coherence states.