Non-Hermitian Topological End-Mode Lasing in Polariton Systems

TL;DR

This paper predicts and analyzes non-Hermitian topological end states in exciton-polariton lattices, revealing new bulk-boundary correspondence and demonstrating topological lasing in a microcavity system.

Contribution

It introduces a novel topological phase transition driven by laser pump patterns and establishes a new bulk-boundary correspondence for non-Hermitian systems.

Findings

Existence of topologically protected end states in polariton lattices

Topological transitions driven by laser pump patterns

Demonstration of topological lasing in a microcavity lattice

Abstract

We predict the existence of non-Hermitian topologically protected end states in a one-dimensional exciton-polariton condensate lattice, where topological transitions are driven by the laser pump pattern. We show that the number of end states can be described by a Chern number and a topological invariant based on the Wilson loop. We find that such transitions arise due to {\it enforced exceptional points} which can be predicted directly from the bulk Bloch wave functions. This allows us to establish a new type of bulk-boundary correspondence for non-Hermitian systems and to compute the phase diagram of an open chain analytically. Finally, we demonstrate topological lasing of a single end-mode in a realistic model of a microcavity lattice.