Simultaneous Observation of Topological Edge State and Exceptional Point in an Open and Non-Hermitian System

TL;DR

This study experimentally demonstrates the coexistence of topological edge states and exceptional points in an acoustic system with non-Hermitian properties, highlighting novel wave phenomena in open systems.

Contribution

It provides the first experimental observation of topological edge states alongside exceptional points in a non-Hermitian acoustic system with synthetic dimensions.

Findings

Unidirectional reflectionless propagation observed

Topological edge states confirmed in experiments

Exceptional point characteristics demonstrated

Abstract

This paper reports on the experimental observation of topologically protected edge state and exceptional point in an open and Non-Hermitian system. While the theoretical underpinning is generic to wave physics, the simulations and experiments are performed for an acoustic system whose structure has non-trivial topological properties that can be characterized by the Chern number provided that a synthetic dimension is introduced. Unidirectional reectionless propagation, a hallmark of exceptional point, is unambiguously observed in both simulations and experiments.