论文标题
经典的输入和测量值使相位灵敏度超出了射击限制
Classical Inputs and Measurements Enable Phase Sensitivity beyond the Shot-Noise Limit
论文作者
论文摘要
基于状态的相位估计是对精确测量领域的富有成果的测试床，因为与外来量子状态相比，相干状态可强大地与破坏。洞穴完成的开创性工作（https://doi.org/10.1103/physrevd.23.1693，Phys。Rev.D 23，1693（1981））指出，用相干状态喂养的U（2）干涉仪的相位灵敏度受射击限制的限制（shot-noise liber）。在这封信中，我们证明了这种结合不是确定的灵敏度限制，并且当测量包括外部相参考时可能会破坏。 SNL可以超过$ \ sqrt {2} $的因子，并且通过计算量子Fisher信息来支持有效性。此外，我们讨论了其他敏感性超出SNL的其他单模高斯输入。我们的工作显示了许多归类场景的潜在应用，尤其是当测量的样品沉浸在巨大的有损环境中或可以承受明亮的照明时。
Coherent-state-based phase estimation is a fruitful testbed for the field of precision measurements since coherent states are robust to decoherence when compared with exotic quantum states. The seminal work done by Caves (https://doi.org/10.1103/PhysRevD.23.1693 , Phys. Rev. D 23, 1693 (1981)) stated that the phase sensitivity of a U(2) interferometer fed with a coherent state is limited by the shot-noise limit (SNL). In this Letter, we demonstrate that this bound is not conclusive sensitivity limit and can be broken when the measurement includes an external phase reference. The SNL can be surpassed by a factor of $\sqrt{2}$ and the validity is supported through the calculation of quantum Fisher information. Additionally, we discuss other single-mode Gaussian inputs of which sensitivities are beyond the SNL. Our work shows potential applications for many metological scenarios, particularly when the measured samples immersed in great lossy environments or can withstand bright illumination.
