Accelerated Non-Reciprocal Transfer of Energy Around an Exceptional Point

TL;DR

This paper introduces a perturbative Magnus expansion method to accurately model and control non-Hermitian systems near exceptional points, enabling fast, high-fidelity non-reciprocal topological operations.

Contribution

It presents a novel perturbative approach using Magnus expansion for non-Hermitian systems, improving control and speed of topological operations around exceptional points.

Findings

Magnus-based perturbative solutions accurately describe system evolution.

Fast non-reciprocal operations with high fidelity are achievable.

Control strategies significantly outperform adiabatic methods.

Abstract

We develop perturbative methods to study and control dynamical phenomena related to exceptional points in Non-Hermitian systems. In particular, we show how to find perturbative solutions based on the Magnus expansion that accurately describe the evolution of non-Hermitian systems when encircling an exceptional point. This allows us to use the recently proposed Magnus-based strategy for control to design fast non-reciprocal, topological operations whose fidelity error is orders of magnitude smaller than their much slower adiabatic counterparts.