Non-Hermitian theory is a theoretical framework used to describe open systems. It offers a
powerful tool in the characterization of both the intrinsic degrees of freedom of a system and …

The topological properties of an object, associated with an integer called the topological
invariant, are global features that cannot change continuously but only through abrupt …

Non-Hermitian systems distinguish themselves from Hermitian systems by exhibiting a
phase transition point called an exceptional point (EP), at which two eigenstates coalesce …

Both theoretical and experimental studies of topological phases in non-Hermitian systems
have made a remarkable progress in the last few years of research. In this article, we review …

Any system of coupled oscillators may be characterized by its spectrum of resonance
frequencies (or eigenfrequencies), which can be tuned by varying the system's parameters …

Non-Hermitian systems with parity-time-(PT)-symmetric complex potentials can exhibit a
phase transition when the degree of non-Hermiticity is increased. Two eigenstates coalesce …

Eigenstates of a non-Hermitian system exist on complex Riemannian manifolds, with
multiple sheets connecting at branch cuts and exceptional points (EPs). These eigenstates …

This Letter introduces a new class of robust states known as exceptional bound (EB) states,
which are distinct from the well-known topological and non-Hermitian skin boundary states …

The effects of gain and loss on the band structures of a bulk topological dielectric photonic
crystal (PC) with C 6 v symmetry and the PC-air-PC interface are studied based on first …

We design a non-parity-time-symmetric plasmonic waveguide-cavity system, consisting of
two metal-dielectric-metal stub resonators side coupled to a metal-dielectric-metal …