近日，北京计算科学研究中心的薛鹏与东南大学的张祥等人合作并取得一项新进展。经过不懈努力，他们对量子行走中的非布洛赫宇称-时间对称相变进行了研究。相关研究成果已于2024年11月6日在国际知名学术期刊《物理评论A》上发表。

在本文中，该研究团队观察了光子量子行走中的宇称-时间（PT）相变，该相变只能通过依赖于开放边界条件的非布洛赫能带理论来解释。此外，研究人员还探讨了无序对PT对称性的影响，并展示了无序诱导的PT相变。这项研究工作为进一步探索非厄米物理提供了有价值的视角。

据悉，宇称-时间（PT）对称性在非厄米物理系统中得到了广泛研究，因为它能够确保具有非厄米哈密顿量的系统存在实本征能量。以往的研究大多基于布洛赫能带理论。然而，最近的发展揭示了一些，只能通过非布洛赫能带理论来解释的有趣现象。

附：英文原文

Title: Non-Bloch parity-time-symmetric phase transition in quantum walks

Author: Bingzi Huo, Quan Lin, Lei Xiao, Xiang Zhan, Dengke Qu, Peng Xue

Issue&Volume: 2024/11/06

Abstract: Parity-time (PT) symmetry is extensively studied within non-Hermitian physical systems as it has the capability to ensure the presence of real eigenenergies of the systems characterized by non-Hermitian Hamiltonians. Previous studies have been mostly based on the Bloch band theory. Recent developments have unveiled intriguing phenomena which can only be explained by non-Bloch band theory. In this paper, we observe the PT phase transition in photonic quantum walks, which can only be explained by the non-Bloch band theory, which relies on the open boundary condition. Furthermore, we explore the impact of disorder on PT symmetry and demonstrate disorder-induced PT phase transitions. Our work provides a valuable perspective for further explorations on non-Hermitian physics.

DOI: 10.1103/PhysRevA.110.052410

Source: https://journals.aps.org/pra/abstract/10.1103/PhysRevA.110.052410