Quantum Fisher information of entangled coherent states in the presence of photon loss
Quantum Fisher information of entangled coherent states in the presence of photon loss
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DOI：
10.1103/physreva.88.043832
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发表时间：
2013-07
影响因子：
2.9
通讯作者：
Y. M. Zhang;X. Li;Weitao Yang;G. Jin
中科院分区：
文献类型：
--
作者：
Y. M. Zhang;X. Li;Weitao Yang;G. Jin
我们研究了用于量子增强相位估计的纠缠相干态的性能。导出了量子费希尔信息的精确解析表达式，以显示光子损失对最终相位灵敏度的作用。我们发现由于光子态的量子退相干，灵敏度从海森堡标度到经典标度的转变。这种量子经典转变是由丢失的光子数量唯一决定的，而不是仅由入射光子数量或光子丢失率决定。我们的结果还表明，即使光子损失率非常小，纠缠相干态和 NOON 态之间的灵敏度也会发生交叉。
We investigate the performance of entangled coherent states for quantum-enhanced phase estimation. An exact analytical expression of quantum Fisher information is derived to show the role of photon losses on the ultimate phase sensitivity. We find a transition of the sensitivity from the Heisenberg scaling to the classical scaling due to quantum decoherence of the photon state. This quantum-classical transition is uniquely determined by the number of photons being lost, instead of the number of incident photons or the photon loss rate alone. Our results also reveal that a crossover of the sensitivity between the entangled coherent state and the NOON state can occur even for very small photon loss rate.