Non-Hermitian Topology in Quantum Physics
Non-Hermiticity enriches topological phases beyond the existing framework for Hermitian topological phases. Unique non-Hermitian topological phenomena have been observed in several classical experiments of mechanical metamaterials, electrical circuits, photonic lattices, and active particles. Recently, beyond the classical regime, signatures of non-Hermitian topology have been experimentally observed also in open quantum atomic and photonic systems. However, it has been unclear how to theoretically characterize non-Hermitian topological phases in quantum many-body systems. In this seminar, we formulate a many-body topological invariant intrinsic to non-Hermitian systems in one dimension . We also discuss entanglement dynamics and phase transitions induced by non-Hermitian topology .
References: K. Kawabata, K. Shiozaki, and S. Ryu, Phys. Rev. B 105, 165137 (2022)  K. Kawabata, T. Numasawa, and S. Ryu, in preparation.