近日，中国科学技术大学项国勇团队研究了耗散里德伯气体中多体稳态的手性开关。该项研究成果发表在2025年8月28日出版的《科学通报》杂志上。

耗散里德伯气体是研究多体开放系统的一个杰出平台。尽管已有丰富的研究，耗散里德伯气体的非平衡动力学很少通过非厄米物理的透镜来检查或利用，这只是开放系统固有的。

研究组报道了耗散热里德伯蒸汽中多体稳态之间的手性转换的实验观察，这是由系统的刘维安特征谱中的特殊结构所支持的。与非厄米系统中的典型手性态转移类似，由于参数在闭合轮廓周围绝热变化，取决于参数调制的手性，里德伯蒸气可以在两个具有不同里德伯激发和光传输的集体稳态之间变化。

采用平均场描述，研究组揭示了双稳稳态和手性动力学的存在都源于Liouvillian异常结构，其中两条异常线在高阶异常点合并。这种耗散里德伯气体的非厄米视角不仅为通过多体参数进行手性模式切换提供了一个新的范例，正如研究组在实验中所证明的那样，还为基于非厄米物理的独特特征设计新的应用铺平了道路。

附：英文原文

Title: Chiral switching of many-body steady states in a dissipative Rydberg gas

Author: anonymous

Issue&Volume: 2025/08/28

Abstract: Dissipative Rydberg gases are an outstanding platform for the investigation of many-body open systems. Despite the wealth of existing studies, the non-equilibrium dynamics of dissipative Rydberg gases has rarely been examined or harnessed through the lens of non-Hermitian physics, which is but intrinsic to open systems. Here we report the experimental observation of chiral switching between many-body steady states in a dissipative thermal Rydberg vapor, which is underlain by an exceptional structure in the Liouvillian eigenspectrum of the system. Similar to typical chiral state transfer in non-Hermitian systems, as the parameters are adiabatically varied around a closed contour, depending on the chirality of the parameter modulation, the Rydberg vapor can change between two collective steady states with distinct Rydberg excitations and optical transmissions. Adopting a mean-field description, we reveal that both the existence of the bistable steady states and chiral dynamics derive from the Liouvillian exceptional structure, where two exceptional lines merge at a higher-order exceptional point. Such a non-Hermitian perspective of the dissipative Rydberg gas not only provides a new paradigm for chiral mode switching through many-body parameters, as we demonstrate experimentally, but also paves the way for devising novel applications based on the unique features of non-Hermitian physics.

DOI: 10.1016/j.scib.2025.08.051

Source: https://www.sciencedirect.com/science/article/abs/pii/S2095927325008898