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arXiv 1908.11081quant-ph
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通过平均能量的知识提高灵敏度极限

Enhancement of the metrological sensitivity limit through knowledge of the average energy

Manuel Gessner

摘要:

我们考虑的问题,量子相位估计与访问任意测量在一个单一的次优基础。在这种情况下,可实现的灵敏度极限由经典的Cramér-Rao界相对于固定基确定。在这里,我们表明,如果有关能量期望值的知识是可用的,灵敏度可以提高超过这个限制。所示的组合的信息是相当于一个直接测量的基础投影仪和相位印记哈密顿的最佳线性组合。应用于具有过压缩自旋态的原子钟,产生与原子数成线性比例的灵敏度增益。我们的分析进一步表明,观察到的小修改可以对灵敏度产生强烈的影响。

英文摘要:

We consider the problem of quantum phase estimation with access to arbitrary measurements in a single suboptimal basis. The achievable sensitivity limit in this case is determined by the classical Cramér-Rao bound with respect to the fixed basis. Here we show that the sensitivity can be enhanced beyond this limit if knowledge about the energy expectation value is available. The combined information is shown to be equivalent to a direct measurement of an optimal linear combination of the basis projectors and the phase-imprinting Hamiltonian. Application to an atomic clock with oversqueezed spin states yields a sensitivity gain that scales linearly with the number of atoms. Our analysis further reveals that small modifications of the observable can have a strong impact on the sensitivity.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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