Unifying Collective Effects in Emission, Absorption, and Transfer

TL;DR

This paper presents a unified framework for understanding collective effects like superradiance and subradiance across different quantum systems, enabling better design of resilient quantum devices.

Contribution

It introduces a common Dicke framework that unifies diverse collective effects in emission, absorption, and transfer, facilitating transferability and generalization.

Findings

Unified description of collective effects across different contexts

Generalization of effects from spins to harmonic oscillators

Strategies for engineering noise-robust collective effects

Abstract

Collective effects, such as superradiance and subradiance are central to emerging quantum technologies -- from sensing to energy storage -- and play an important role in light-harvesting. These effects enhance or suppress rates of dynamic processes (absorption, emission, and transfer) due to the formation of symmetric or antisymmetric collective states. However, collective effects in different contexts -- absorption, emission, and transfer -- have often been defined disparately, especially across different communities, leading to results that are not immediately transferable between different contexts. Here, we describe all three types of collective effects using a common Dicke framework that resolves the apparent discrepancies between different approaches. It allows us to generalise previously known collective effects involving spins into new ones involving aggregates of harmonic oscillators or other degrees of freedom. It also explains how collective effects can be engineered to be robust against both disorder and noise, paving the way for more resilient quantum devices.