近日，日本东京大学的Yoshihiko Hasegawa&Wataru Setoyama及其研究团队取得一项新进展。经过不懈努力，他们对基于外差检测的李代数量子相位约化进行研究。相关研究成果已于2025年1月2日在国际知名学术期刊《物理评论A》上发表。

在本研究中，研究人员将量子相位约化方法[W. Setoyama和Y. Hasegawa，物理评论快报 132, 093602 (2024)]扩展到外差检测中，为通过分析所有可能正交可观测量的均匀连续测量来评估量子同步动力学提供了一个全面的理论框架。该方法通过平均化反作用，能够在避免测量引起的相位偏置的同时，无偏见地评估量子振子之间的同步性。

此外，通过独立于特定可观测量定义相位和极限环解，该研究提出的方法能够一致地适应可观测量在时间演化过程中自由修改的场景。通过对噪声诱导同步的模拟，该方法揭示出振子之间的相位簇数量受其玻色子能级限制。

据悉，在量子物理中，测量反作用本质上会改变所观察到的动力学行为。在量子同步领域，这种反作用会引入相位偏置，使得同步的评估严重依赖于所选择的可观测量。

附：英文原文

Title: Lie-algebraic quantum phase reduction based on heterodyne detection

Author: Wataru Setoyama* and Yoshihiko Hasegawa†

Issue&Volume: 2025-01-02

Abstract: Measurement backaction inherently alters observed dynamics in quantum physics. In the realm of quantum synchronization, this backaction induces a phase bias, making the assessment of synchronization critically dependent on the choice of the observables. In this study we extend the quantum phase reduction approach [W. Setoyama and Y. Hasegawa, Phys. Rev. Lett. 132, 093602 (2024)] into heterodyne detection, offering a comprehensive theoretical framework for analyzing quantum synchronization dynamics through uniform continuous measurement over all possible quadrature observables. This method averages out the backaction, allowing for unbiased evaluation of synchronization between quantum oscillators while avoiding measurement-induced phase bias. Furthermore, by defining the phase and limit-cycle solution independently of specific observables, our proposed method consistently adapts to the scenario where the observables are freely modified during the time evolution. Through simulations of noise-induced synchronization, our method reveals that the number of phase clusters between oscillators is restricted by their bosonic levels.

DOI: 10.1103/PhysRevA.111.012202

Source: https://journals.aps.org/pra/abstract/10.1103/PhysRevA.111.012202