上海大学刘俊杰团队近日研究了基于二维磁体的可调谐纳米光子器件和腔。相关论文于2025年7月8日发表在《物理评论A》杂志上。

非厄米系统在实现厄米领域中缺乏对应物的量子信息任务方面显示出了很好的潜力。理解反映在信息论量中的非厄米系统的动力学特性对于推进其应用是必不可少的。

研究组探析了显示奇偶时间对称或反奇偶时间对称的非厄米量子比特系统中分别量化信息流和纠缠的迹距和并发的动力学。他们从系统密度矩阵中识别出动态指纹，为现有研究中观察到的轨迹距离和并发所共有的振荡和松弛动力学提供了统一的解释。还进一步研究了纯脱相影响下动态指纹的命运。

令人惊讶的是，研究组发现纯减相可以减缓具有不破缺反奇偶时间对称性的非厄米系统中信息流和纠缠的固有弛豫，这表明在这类非厄米系统中存在被动环境辅助信息保护。该发现增强了他们对动态非厄米系统的理解，并与面向信息的应用具有特定的相关性。

附：英文原文

Title: Dynamical non-Hermitian systems: Fingerprints and pure-dephasing-induced protection effect

Author: Wanchen Ma, Hao Zhang, Junjie Liu

Issue&Volume: 2025/07/08

Abstract: Non-Hermitian systems have shown promising potential for realizing quantum information tasks that lack counterparts in the Hermitian realm. Understanding the dynamical characteristics of non-Hermitian systems as reflected in information-theoretic quantities is essential for advancing their applications. Here we investigate the dynamics of the trace distance and concurrence, which quantify information flow and entanglement, respectively, in non-Hermitian qubit systems exhibiting either parity-time or anti-parity-time symmetry. We identify dynamical fingerprints from the system density matrix which provide a unified explanation to the common oscillation and relaxation dynamics shared by the trace distance and concurrence observed in existing studies. We further investigate the fate of dynamical fingerprints under the impact of pure dephasing. Surprisingly, we find that pure dephasing can slow down the inherent relaxation of information flow and entanglement in non-Hermitian systems with unbroken anti-parity-time symmetry, suggesting a passive environment-assisted information protection in this class of non-Hermitian systems. Our findings enhance our understanding of dynamical non-Hermitian systems and have specific relevance to their information-oriented applications.

DOI: 10.1103/5d73-nrtb

Source: https://journals.aps.org/pra/abstract/10.1103/5d73-nrtb