Fisher Information and the Quantum Cramer-Rao Sensitivity Limit of Continuous Measurements
Fisher Information and the Quantum Cramer-Rao Sensitivity Limit of Continuous Measurements
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DOI：
10.1103/physrevlett.112.170401
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发表时间：
2014-04-28
影响因子：
8.6
通讯作者：
Molmer, Klaus
中科院分区：
文献类型：
--
作者：
Gammelmark, Soren;Molmer, Klaus
量子系统的精确测量依赖于我们追踪实验信号之间的差异到未知物理参数变化的能力。本文推导了开放量子系统连续测量参数估计的Fisher信息和相应的Cramer-Rao灵敏度极限。我们通过将其应用于激光驱动的两态原子的共振荧光来说明我们的理论；我们发现光子计数和同差探测记录对原子参数产生不同的灵敏度，但它们都没有超过我们的一般结果。
Precision measurements with quantum systems rely on our ability to trace the differences between experimental signals to variations in unknown physical parameters. In this Letter we derive the Fisher information and the ensuing Cramer-Rao sensitivity limit for parameter estimation by continuous measurements on an open quantum system. We illustrate our theory by its application to resonance fluorescence from a laser-driven two-state atom; we show that photon counting and homodyne detection records yield different sensitivity to the atomic parameters, while none of them exceed our general result.