“Topological Origin of Non-Hermitian Skin Effects” (2020), by Nobuyuki Ōkuma et al. Physics and Astronomy research paper. Original abstract below, unchanged. A free PDF is available.

Topological Origin of Non-Hermitian Skin Effects

Nobuyuki Ōkuma, Kohei Kawabata, Ken Shiozaki et al. · February 25, 2020 · Physics and Astronomy

Abstract

A unique feature of non-Hermitian systems is the skin effect, which is the extreme sensitivity to the boundary conditions. Here, we reveal that the skin effect originates from intrinsic non-Hermitian topology. Such a topological origin not merely explains the universal feature of the known skin effect, but also leads to new types of the skin effects-symmetry-protected skin effects. In particular, we discover the Z₂ skin effect protected by time-reversal symmetry. On the basis of topological classification, we also discuss possible other skin effects in arbitrary dimensions. Our work provides a unified understanding about the bulk-boundary correspondence and the skin effects in non-Hermitian systems.

Free PDF DOI: 10.1103/physrevlett.124.086801