Dynamical Degeneracy Splitting and Directional Invisibility in Non-Hermitian Systems postprint

Abstract: In this paper, we propose the concept called dynamical degeneracy splitting to characterize the anisotropic decay behaviors in non-Hermitian systems. We show that when the system has dynamical degeneracy splitting, it will exhibit (i) anomalous scattering in the bulk and (ii) the non-Hermitian skin effect under the open boundary condition of a generic geometry. As an application, we propose directional invisibility in terms of wave packet dynamics to probe the geometry-dependent skin effect in higher dimensions. Our work provides a feasible way to detect the non-Hermitian skin effect in experiments.