Response strengths of open systems at exceptional points

TL;DR

This paper investigates the unique response behaviors of open quantum and wave systems at exceptional points, introducing new characteristics to quantify their sensitivity and dynamics, with validation across various physical examples.

Contribution

It introduces two new characteristics to quantify the response of systems at exceptional points, offering a novel perspective on their physics.

Findings

Exceptional points cause strong responses to perturbations.

New characteristics effectively quantify energy and state responses.

Verification across multiple physical systems confirms the concepts.

Abstract

Open quantum and wave systems exhibit exotic degeneracies at exceptional points in parameter space that have attracted considerable attention in various fields of physics, including optics and photonics. One reason is the strong response of open systems at such degeneracies to external perturbations and excitations. We introduce two characteristics of exceptional points that quantify the response in terms of energy eigenvalues and eigenstates, intensity, and dynamics. The concept is verified for several physically relevant examples. This work provides a new perspective on the physics of exceptional points.