The chirality of chiral multifold fermions in reciprocal space is related to the chirality of crystal lattice structures in real space. In this study, we propose a strategy to detect and identify multifold fermions of opposite chirality in nonmagnetic systems using second-order optical transports. Chiral crystals related with inversion operations cannot be made to overlap with each other via any experimental operation. Further, chiral multifold fermions within such crystals host opposite chiralities corresponding to a given $k$ point. A change in chirality is indicated by a corresponding change in the sign of the second-order charge current dominated by chiral fermions. This property can be exploited to study the relationship between chiralities in reciprocal and real spaces by utilizing bulk transport.

中文翻译：

---

光学方法检测相互空间手性多重费米子手性与真实空间手性晶体之间的关系

互空间中的手性多重费米子的手性与现实空间中晶格结构的手性有关。在这项研究中，我们提出了一种使用二阶光学传输来检测和识别非磁性系统中相反手性的多重费米子的策略。与反转操作有关的手性晶体不能通过任何实验操作彼此重叠。此外，此类晶体中的手性多重费米子具有与给定给定相对的手性$ķ$点。手性的变化由手性费米子主导的二阶电荷电流的符号的相应变化指示。通过利用散装运输，可以利用此属性来研究互惠空间和真实空间中的手性之间的关系。