Wang Pengfei, Kwon Hyukjoon, Luan Chun-Yang, Chen Wentao, Qiao Mu, Zhou Zinan, Wang Kaizhao, Kim M S, Kim Kihwan
Beijing Academy of Quantum Information Sciences, Beijing, China.
State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing, China.
Nat Commun. 2024 Oct 16;15(1):8900. doi: 10.1038/s41467-024-53051-5.
Measurement-induced state disturbance is a major challenge in obtaining quantum statistics at multiple time points. We propose a method to extract dynamic information from a quantum system at intermediate time points, namely snapshotting quantum dynamics. To this end, we apply classical post-processing after performing the ancilla-assisted measurements to cancel out the impact of the measurements at each time point. Based on this, we reconstruct a multi-time quasi-probability distribution (QPD) that correctly recovers the probability distributions at the respective time points. Our approach can also be applied to simultaneously extract exponentially many correlation functions with various time-orderings. We provide a proof-of-principle experimental demonstration of the proposed protocol using a dual-species trapped-ion system by employing Yb and Ba ions as the system and the ancilla, respectively. Multi-time measurements are performed by repeated initialization and detection of the ancilla state without directly measuring the system state. The two- and three-time QPDs and correlation functions are reconstructed reliably from the experiment, negativity and complex values in the QPDs clearly indicate a contribution of the quantum coherence throughout dynamics.
测量引起的态扰动是在多个时间点获取量子统计信息时面临的一项重大挑战。我们提出了一种在中间时间点从量子系统中提取动态信息的方法，即快照量子动力学。为此，我们在执行辅助测量后应用经典后处理，以消除每个时间点测量的影响。基于此，我们重建了一个多时间准概率分布（QPD），它能正确恢复各个时间点的概率分布。我们的方法还可用于同时提取指数级数量的具有各种时间排序的关联函数。我们使用双物种囚禁离子系统，分别将镱离子和钡离子用作系统和辅助粒子，对所提出的协议进行了原理验证实验演示。通过重复初始化和检测辅助粒子状态而不直接测量系统状态来进行多时间测量。从实验中可靠地重建了二次和三次QPD以及关联函数，QPD中的负性和复数值清楚地表明了量子相干在整个动力学过程中的贡献。
