研究压缩真空环境下二能级系统的相位参数估计,考察压缩态参数N和相位参数取值的不同对量子Fisher信息的影响,重点讨论提高参数估计精度的办法。结果表明:二能级系统相位参数估计的量子Fisher信息随时间衰减,随压缩相位参数周期性变化。当压缩参数N取值较大时,量子Fisher信息衰减缓慢,二能级系统的相位估计精度高。

This paper studied estimation of the phase parameter of a two-state system in a squeezed bath,investigated the effects of the parameter N and the squeezing phase  of the squeezed bath on quantum Fisher information,and focused on the enhancement of the estimation precision.The results showed that,the quantum Fisher information decays with time and changes periodically with the squeezing phase .When the value of the squeezing parameter N is larger,the quantum Fisher information decays more slowly and the estimation precision can be enhanced.