摘要
According to the Lorentz reciprocity theorem, an electromagnetic wave has the reciprocity of bi-directional transmission through ordinary time inversion invariant media. In some special systems(such as optical isolators and annular devices), however, a transmission can be nonreciprocal, and such transmission is typical so far. Despite the critical role of quantum nonreciprocal devices in chiral quantum technology and topological photonics [1], their physical realization remains challenging.
