近日，深圳大学汪国平团队研究了无损介质中不可去除的异常点的时间散射。这一研究成果于2026年1月6日发表在《物理评论A》杂志上。

课题组研究了无损德鲁德介质中的时间散射，揭示了与静态极化电荷相关的零频率平带所扮演的被忽视的角色。该平带形成了一条跨越所有波数的特殊线，在光子时间界面处的时间散射过程中可直接被激发，从而在通常的反射波和透射波之外产生非传播的静态场。

在相应的特殊点处，本征矢量聚合导致了两个在先前研究系统中不存在的独特特征：一个振幅随时间线性增加的静态模式，以及由系统广义本征矢量产生的额外静态分量。值得注意的是，这些效应的发生并不违反总能守恒定律，凸显了动力学的厄米特性。该发现呈现了一种与无色散和洛伦兹色散介质截然不同的时间散射物理图景。

附：英文原文

Title: Temporal scattering at irremovable exceptional points in lossless Drude media

Author: Neng Wang, Shuyong Chen, Guo Ping Wang

Issue&Volume: 2026/01/06

Abstract: We investigate temporal scattering in lossless Drude media and reveal an overlooked role of the zero-frequency flatband associated with static polarization charge. This flatband forms an exceptional line spanning all wave numbers and can be directly excited during temporal scattering at photonic time interfaces, generating nonpropagating static fields alongside the usual reflected and transmitted waves. Eigenvector coalescence at the corresponding exceptional points leads to two distinctive features absent in previously studied systems: a static mode whose amplitude increases linearly with time and an additional static component arising from the systems generalized eigenvector. Remarkably, these effects occur without violating total energy conservation, underscoring the Hermitian nature of the dynamics. Our findings present an alternative physical picture of temporal scattering, sharply distinct from that in dispersionless and Lorentz-dispersive media.

DOI: 10.1103/2bkl-1gld

Source: https://journals.aps.org/pra/abstract/10.1103/2bkl-1gld