Interplay between spontaneous decay rates and Lamb shifts in open photonic systems

TL;DR

This paper investigates how spontaneous decay rates and Lamb shifts of quantum emitters are affected by open photonic systems, revealing that open systems can exhibit Lamb shifts exceeding the emission linewidth, unlike closed systems.

Contribution

It introduces a framework linking decay rates and Lamb shifts to resonant states in open photonic systems, highlighting fundamental differences from closed systems.

Findings

Lamb shift can surpass emission linewidth in open systems.

Decay rates are related to resonant states of photonic resonators.

Open systems exhibit unbounded Lamb shifts unlike closed systems.

Abstract

In this letter, we describe the modified decay rate and photonic Lamb (frequency) shift of quantum emitters in terms of the resonant states of a neighboring photonic resonator. This description illustrates a fundamental distinction in the behaviors of closed (conservative) and open (dissipative) systems: the Lamb shift is bounded by the emission linewidth in closed systems while it overcomes this limit in open systems.