Liu Gang-Qin, Zhang Yu-Ran, Chang Yan-Chun, Yue Jie-Dong, Fan Heng, Pan Xin-Yu
Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
1] Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China [2] Collaborative Innovation Center of Quantum Matter, Beijing 100190, China.
Nat Commun. 2015 Apr 2;6:6726. doi: 10.1038/ncomms7726.
Precise parameter estimation plays a central role in science and technology. The statistical error in estimation can be decreased by repeating measurement, leading to that the resultant uncertainty of the estimated parameter is proportional to the square root of the number of repetitions in accordance with the central limit theorem. Quantum parameter estimation, an emerging field of quantum technology, aims to use quantum resources to yield higher statistical precision than classical approaches. Here we report the first room-temperature implementation of entanglement-enhanced phase estimation in a solid-state system: the nitrogen-vacancy centre in pure diamond. We demonstrate a super-resolving phase measurement with two entangled qubits of different physical realizations: an nitrogen-vacancy centre electron spin and a proximal (13)C nuclear spin. The experimental data shows clearly the uncertainty reduction when entanglement resource is used, confirming the theoretical expectation. Our results represent an elemental demonstration of enhancement of quantum metrology against classical procedure.
精确的参数估计在科学技术中起着核心作用。通过重复测量可以减小估计中的统计误差，根据中心极限定理，这会导致估计参数的最终不确定性与重复次数的平方根成正比。量子参数估计是量子技术的一个新兴领域，旨在利用量子资源产生比经典方法更高的统计精度。在此，我们报告了在固态系统——纯金刚石中的氮空位中心实现的首个室温下的纠缠增强相位估计。我们用两个具有不同物理实现的纠缠量子比特展示了超分辨相位测量：一个氮空位中心电子自旋和一个近端的（13）C核自旋。实验数据清楚地表明了使用纠缠资源时不确定性的降低，证实了理论预期。我们的结果代表了量子计量相对于经典方法增强的一个基本证明。
