Optimal simultaneous measurements of incompatible observables of a single photon
Optimal simultaneous measurements of incompatible observables of a single photon
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DOI：
10.1364/optica.6.000257
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发表时间：
2018-08
期刊：
影响因子：
10.4
通讯作者：
A. Dada;W. McCutcheon;E. Andersson;J. Crickmore;I. Puthoor;B. Gerardot;A. McMillan;J. Rarity;R. Oulton
中科院分区：
文献类型：
--
作者：
A. Dada;W. McCutcheon;E. Andersson;J. Crickmore;I. Puthoor;B. Gerardot;A. McMillan;J. Rarity;R. Oulton
测量精度的极限是由量子力学定律决定的。最吸引人的结果之一是，对非对易量子可见进行联合或同时测量是可能的，代价是不清晰度或测量不确定性增加。有许多不同的标准可用来确定什么是“最佳”联合测量，这些测量具有相应的不同权衡关系。通常，设计或实施使联合测量不确定度降至最低的策略是一项非常重要的任务。在这里，我们实现了最简单的可能的最优四结果联合测量技术，并演示了一种以前在光子环境中尚未实现的最优测量类型。我们通过实验研究了一种更基本的联合测量不确定度关系，因为它只涉及概率，并且与分配给测量结果的值无关。利用一个预知的单光子源，我们证明了该方案在单量子条件下的量子受限性能。由于量子测量是量子信息科学中许多概念的基础，因此这项研究既具有基本的兴趣，也与新兴的光子量子技术相关。
The ultimate limits of measurement precision are dictated by the laws of quantum mechanics. One of the most fascinating results is that joint or simultaneous measurements of noncommuting quantum observables are possible at the cost of increased unsharpness or measurement uncertainty. Many different criteria exist for determining what an “optimal” joint measurement is, with corresponding different trade-off relations for the measurements. It is generally a nontrivial task to devise or implement a strategy that minimizes the joint-measurement uncertainty. Here, we implement the simplest possible technique for an optimal four-outcome joint measurement and demonstrate a type of optimal measurement that has not been realized before in a photonic setting. We experimentally investigate a joint-measurement uncertainty relation that is more fundamental in the sense that it refers only to probabilities and is independent of values assigned to measurement outcomes. Using a heralded single-photon source, we demonstrate quantum-limited performance of the scheme on single quanta. Since quantum measurements underpin many concepts in quantum information science, this study is both of fundamental interest and relevant for emerging photonic quantum technologies.