Wave packet dynamics in a non-Hermitian exciton-polariton system

TL;DR

This paper theoretically explores wave packet dynamics in a non-Hermitian exciton-polariton system, revealing phenomena like self-acceleration, eigenstate selection, and topological defects, with potential experimental observations.

Contribution

It introduces a theoretical framework for understanding wave packet behavior in non-Hermitian exciton-polariton systems, highlighting novel effects related to exceptional points and topological defects.

Findings

Wave packets exhibit self-acceleration and reshaping due to eigenenergy properties.

Wave packets tend to self-organize into states with minimal decay, enabling directional transport.

Formation of pseudospin topological defects on the imaginary Fermi arc.

Abstract

We theoretically investigate the dynamics of wave packets in a generic, non-Hermitian, optically anisotropic exciton-polariton system that exhibits degeneracies of its complex-valued eigenenergies in the form of pairs of exceptional points in momentum space. We observe the self-acceleration and reshaping of the wave packets governed by their eigenenergies. We further find that the exciton-polariton wave packets tend to self-organize into the eigenstate with the smaller decay rate, then propagate towards the minima of the decay rates in momentum space, resulting in directional transport in real space. We also describe the formation of pseudospin topological defects on the imaginary Fermi arc, where the decay rates of the two eigenstate coincide in momentum space. These effects of non-Hermiticity on the dynamics of exciton polaritons can be observed experimentally in a microcavity with optically anisotropic cavity spacer or exciton-hosting materials.