近日，香港中文大学孙贤开团队报道了连续统中具有束缚态的反PT对称。相关论文于2026年7月7日发表在《光：科学与应用》杂志上。

满足PT对称或反PT对称的非厄米系统已产生许多有趣的波动现象。维持厄米（非厄米）性质并增大非厄米（厄米）性质差异，可通过例外点（EP）引发从对称相到破缺相的相变。然而，在实验上构建一个同时满足这两种要求且工作在EP的系统十分困难。连续域中的束缚态（BIC）是一种特殊的无损耗波态，尽管它与连续波共存。偏离BIC会导致一个本质上具有耗散的准BIC。

研究组提出从二元准BIC系统中实现反PT对称，其中在两个准BIC之间引入的不对称性通过EP诱导了反PT相变。在实验上，研究组利用热光效应精确控制不对称性，并演示了反PT相变。他们还发现，尽管存在制造缺陷，该系统仍可在EP下工作，这由群指数超过40的慢光效应所证实。通过利用BIC构建反PT对称，该方法为非厄米物理的基础研究和实际应用开辟了一条新途径。

附：英文原文

Title: Anti-PT symmetry with bound states in the continuum

Author: Feng, Ziyao, Jin, Long, Sun, Xiankai

Issue&Volume: 2026-07-07

Abstract: Non-Hermitian systems satisfying PT- or anti-PT symmetry have produced many intriguing wave phenomena. Maintaining the Hermitian (non-Hermitian) property and increasing the non-Hermitian (Hermitian) property difference can cause a phase transition from a symmetric phase to a broken phase through the exceptional point (EP). However, it is experimentally difficult to construct a system working at the EP to satisfy both requirements simultaneously. Bound states in the continuum (BICs) are a special lossless wave state despite their coexistence with continuous waves. Deviation from a BIC leads to an intrinsically dissipative quasi-BIC. Here, we propose to attain anti-PT symmetry from a binary quasi-BIC system, where an introduced asymmetry between two quasi-BICs induces an anti-PT phase transition through the EP. Experimentally, we used the thermo-optic effect to accurately control the asymmetry and demonstrated an anti-PT phase transition. We further found that the system can operate at the EP despite fabrication imperfections, evidenced by the slow-light effect with a group index exceeding 40. By harnessing BICs for constructing anti-PT symmetry, our approach opens up a new way for fundamental research and practical applications based on non-Hermitian physics.

DOI: 10.1038/s41377-026-02354-x

Source: https://www.nature.com/articles/s41377-026-02354-x

期刊信息

Light: Science & Applications：《光：科学与应用》，创刊于2012年。隶属于施普林格·自然出版集团，最新IF：19.4

官方网址：https://www.nature.com/lsa/

投稿链接：https://mts-lsa.nature.com/cgi-bin/main.plex