Critical dephasing rates for the observation of collective behavior in a pair of coupled quantum emitters

TL;DR

This paper theoretically investigates the critical dephasing rates that suppress collective effects like superradiance in a pair of coupled quantum emitters, providing thresholds to guide experimental observation.

Contribution

It identifies observable-dependent dephasing thresholds for collective phenomena in two coupled quantum emitters, offering a quantitative framework for experimental optimization.

Findings

Threshold dephasing rates vary with observable

Collective effects vanish beyond certain dephasing levels

Framework aids in experimental design for quantum collectivity

Abstract

Efficient atom-photon interfaces require the controlled assembly of quantum emitters, where collective effects such as superradiance and subradiance can emerge. Recent experiments with subwavelength arrays of quantum dots have observed superradiance at room temperature, revealing a delicate competition between collective enhancement of coherent emission and pure dephasing $\gamma^*$, which destroys it. Motivated by these results, we theoretically study $N=2$ coupled quantum emitters and identify threshold values of $\gamma^*$, for four experimentally accessible observables, beyond which collective effects vanish. The thresholds depend sensitively on the chosen observable, highlighting the subtlety of detecting collective behavior. Our work provides a quantitative framework to guide experiments and optimize conditions for observing collective quantum phenomena.