近日，北京大学的何琼毅及其研究小组与瑞士苏黎世联邦理工学院的Matteo Fadel合作并取得一项新进展。经过不懈努力，他们利用压缩的克尔振荡器实现量子计量。相关研究成果已于2024年5月6日在国际知名学术期刊《物理评论A》上发表。

该研究团队研究了克尔-非线性振荡器中的压缩动力学，并量化了所得状态的计量用途。尽管非线性使演化过程非高斯化，从而限制了压缩的效果，但这些状态依然展现出在位移传感方面的高量子费雪信息。然而，与高斯状态不同，位移的幅度无法通过简单的正交测量来直接估计。

鉴于此，研究人员提出了一种创新的测量策略，即相互作用后测量协议。该协议在进行线性正交测量之前，引入了一个额外的非线性演化过程，并证明这种策略能够显著提高位移测量的灵敏度。当考虑到诸如能量松弛等现实缺陷时，该研究结果依然是鲁棒的，并且可以在最先进的实验平台中实现。

附：英文原文

Title: Quantum metrology with a squeezed Kerr oscillator

Author: Jiajie Guo, Qiongyi He, Matteo Fadel

Issue&Volume: 2024/05/06

Abstract: We study the squeezing dynamics in a Kerr-nonlinear oscillator, and quantify the metrological usefulness of the resulting states. Even if the nonlinearity limits the attainable squeezing by making the evolution non-Gaussian, the states obtained still have a high quantum Fisher information for sensing displacements. However, contrary to the Gaussian case, the amplitude of the displacement cannot be estimated by simple quadrature measurements. Therefore, we propose the use of a measurement-after-interaction protocol where a linear quadrature measurement is preceded by an additional nonlinear evolution, and show the significant sensitivity enhancement that can be obtained. Our results are robust when considering realistic imperfections such as energy relaxation, and can be implemented in state-of-the-art experimental setups.

DOI: 10.1103/PhysRevA.109.052604

Source: https://journals.aps.org/pra/abstract/10.1103/PhysRevA.109.052604