近日，山东大学的刘全城与德国奥格斯堡大学的Klaus Ziegler合作并取得一项新进展。经过不懈努力，他们对监测演化下玻色子系统的纠缠态进行研究。相关研究成果已于2024年8月5日在国际知名学术期刊《物理评论A》上发表。
本文研究了在重复投影测量下非相互作用玻色子的演化。按照既定方法，这种受监测的演化特征由首次检测到的返回概率和首次检测到的跃迁概率来表征。该研究团队证明了这些量与二体系统的纠缠熵和纠缠谱直接相关。通过对玻色子数量、测量次数以及测量之间的时间步长赋予特定值进行计算，研究人员发现纠缠熵敏感且经常强烈波动。
特别是，研究人员证明了在时间步长的特定值附近，纠缠熵的演化要么是平稳的，要么在两个或多个平稳值之间进行动态切换。另一方面，在纠缠谱中，这种复杂行为可能与能级交叉有关，表明主要量子态及其纠缠对系统参数的变化有强烈的响应。
此外，研究人员还简要讨论了时间平均在消除纠缠熵波动中的作用。
附：英文原文
Title: Entanglement of bosonic systems under monitored evolution
Author: Quancheng Liu, Klaus Ziegler
Issue&Volume: 2024/08/05
Abstract: The evolution of noninteracting bosons in the presence of repeated projective measurements is studied. Following the established approach, this monitored evolution is characterized by the first detected return and the first detected transition probabilities. We show that these quantities are directly related to the entanglement entropy and the entanglement spectrum of a bipartite system. Calculations with specific values for the number of bosons, the number of measurements, and the time steps between measurements reveal a sensitive and often strongly fluctuating entanglement entropy. In particular, we demonstrate that in the vicinity of special values for the time steps, the evolution of the entanglement entropy either is stationary or performs dynamical switching between two or more stationary values. In the entanglement spectrum, on the other hand, this complex behavior can be associated with level crossings, indicating that the dominant quantum states and their entanglement respond strongly to a change of the system parameters. We discuss briefly the role of time averaging to remove the fluctuations of the entanglement entropy.
DOI: 10.1103/PhysRevA.110.022208
Source: https://journals.aps.org/pra/abstract/10.1103/PhysRevA.110.022208
期刊信息
Physical Review A：《物理评论A》，创刊于1970年。隶属于美国物理学会，最新IF：2.97
官方网址：https://journals.aps.org/pra/
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