Fig. 1: Relationship between point gap and the non-Hermitian skin effect.
From: Anomalous non-Hermitian skin effect: topological inequivalence of skin modes versus point gap
It is taken for granted that the topologically nontrivial (trivial) point gap is equivalent to the presence (absence) of skin modes. However, we question whether this is a universal conclusion. In our work, we exhibit a consequence of the anomalous non-Hermitian skin effect: the open boundary eigenstates being localized for the topologically trivial point gap while extended for the nontrivial point gap.
