In recent years, notions drawn from non-Hermitian physics and parity–time (PT) symmetry have attracted considerable attention. In particular, the realization that the interplay between gain and loss can lead to entirely new and unexpected features has initiated an intense research effort to explore non-Hermitian systems both theoretically and experimentally. Here we review recent progress in this emerging field, and provide an outlook to future directions and developments.

中文翻译：

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非赫米特物理学和PT对称性

近年来，源自非赫米特物理学和奇偶时间（PT）对称性的概念引起了相当大的关注。特别是，认识到增益和损耗之间的相互作用会导致全新的和出乎意料的特征，这引发了人们的大量研究工作，以在理论上和实验上探索非赫米特系统。在这里，我们回顾了这个新兴领域的最新进展，并对未来的方向和发展提供了展望。