论文标题
量子Fisher信息测量和验证量子量子量子量子的量子cramér-rao
Quantum Fisher information measurement and verification of the quantum Cramér-Rao bound in a solid-state qubit
论文作者
论文摘要
量子cramér-rao结合设定了量子系统中无偏参数估计准确性的基本限制，这将确定参数确定参数与量子渔民信息倒数的不确定性有关。我们通过实验证明，在钻石中的氮气胶合中心提供的固态自旋系统的相位估计中，量子cramér-rao接近饱和。这是通过将相估计中的实验不确定性与对相关量子Fisher信息的独立测量进行比较来实现的。后者是从系统在弱参数调制下的连贯动态响应中独立提取的，而无需进行任何量子状态断层扫描。尽管已经观察到涉及有限数量自由度的量子设备的最佳参数估计，但我们的方法提供了一种多功能且强大的实验工具，可探索Cramér-rao绑定和较高复杂性系统中的量子Fisher信息，与量子技术相关。
The quantum Cramér-Rao bound sets a fundamental limit on the accuracy of unbiased parameter estimation in quantum systems, relating the uncertainty in determining a parameter to the inverse of the quantum Fisher information. We experimentally demonstrate near saturation of the quantum Cramér-Rao bound in the phase estimation of a solid-state spin system, provided by a nitrogen-vacancy center in diamond. This is achieved by comparing the experimental uncertainty in phase estimation with an independent measurement of the related quantum Fisher information. The latter is independently extracted from coherent dynamical responses of the system under weak parametric modulations, without performing any quantum-state tomography. While optimal parameter estimation has already been observed for quantum devices involving a limited number of degrees of freedom, our method offers a versatile and powerful experimental tool to explore the Cramér-Rao bound and the quantum Fisher information in systems of higher complexity, as relevant for quantum technologies.
