标题： 非厄米拓扑泵中的异常点 显示英文标题

标题： Exceptional Points in a Non-Hermitian Topological Pump

摘要： 我们研究非厄米性对拓扑泵浦的影响，并揭示了基于拓扑泵浦的拓扑边缘不变量与例外点的绕数之间的联系。 在厄米格子中，已知拓扑泵浦的拓扑非平凡区域仅在无限系统极限下出现。 然而，在有限的非厄米格子中，也可以出现拓扑非平凡行为。 我们表明，这可以通过在泵浦循环中环绕一对例外点的影响来理解。 这一现象在包含可变增益放大器的非厄米微波网络中被实验观察到。 显示英文摘要

摘要： We investigate the effects of non-Hermiticity on topological pumping, and uncover a connection between a topological edge invariant based on topological pumping and the winding numbers of exceptional points. In Hermitian lattices, it is known that the topologically nontrivial regime of the topological pump only arises in the infinite-system limit. In finite non-Hermitian lattices, however, topologically nontrivial behavior can also appear. We show that this can be understood in terms of the effects of encircling a pair of exceptional points during a pumping cycle. This phenomenon is observed experimentally, in a non-Hermitian microwave network containing variable gain amplifiers.