Dressed bound states at chiral exceptional points

TL;DR

This paper reveals how non-Hermiticity in open cavities enables the formation of dressed bound states at chiral exceptional points, with potential applications in quantum sensing, storage, and nonclassical light generation.

Contribution

It introduces two types of dressed bound states in a microring resonator at a chiral exceptional point, providing analytical conditions and demonstrating their unique properties and applications.

Findings

Vacancy-like DBS is immune to cavity dissipation.

Friedrich-Wintgen DBS can be tuned via system parameters.

DBS exhibit potential for quantum device applications.

Abstract

Atom-photon dressed states are a basic concept of quantum optics. Here, we demonstrate that the non-Hermiticity of open cavity can be harnessed to form the dressed bound states (DBS) and identify two types of DBS, the vacancy-like DBS and Friedrich-Wintgen DBS, in a microring resonator operating at a chiral exceptional point. With the analytical DBS conditions, we show that the vacancy-like DBS occurs when an atom couples to the standing wave mode that is a node of photonic wave function, and thus is immune to the cavity dissipation and characterized by the null spectral density at cavity resonance. While the Friedrich-Wintgen DBS can be accessed by continuously tuning the system parameters, such as the atom-photon detuning, and evidenced by a vanishing Rabi peak in emission spectrum, an unusual feature in the strong-coupling anticrossing. We also demonstrate the quantum-optics applications of the proposed DBS. Our work exhibits the quantum states control through non-Hermiticity of open quantum system and presents a clear physical picture on DBS at chiral exceptional points, which holds great potential in building high-performance quantum devices for sensing, photon storage, and nonclassical light generation.