Collectively enhanced ground-state cooling in subwavelength atomic arrays

TL;DR

This paper introduces a novel cooling scheme for atoms in subwavelength arrays that leverages collective subradiant resonances to achieve lower temperatures and ground-state cooling, even when individual atomic transitions are not resolvable.

Contribution

The work demonstrates that dipole-dipole interactions in atomic arrays can enable sideband-resolved cooling and ground-state preparation, expanding the capabilities of quantum control in dense atomic ensembles.

Findings

Subradiant resonances enable lower temperature cooling.

Narrow collective resonances can be sideband-resolved without individual transition resolution.

Ground-state cooling is achievable solely through dipole-dipole interactions.

Abstract

Subwavelength atomic arrays feature strong light-induced dipole-dipole interactions, resulting in subradiant collective resonances characterized by narrowed linewidths. In this work, we present a sideband cooling scheme for atoms trapped in subwavelength arrays that utilizes these narrow collective resonances. Working in the Lamb-Dicke regime, we derive an effective master equation for the atomic motion by adiabatically eliminating the internal degrees of freedom of the atoms, and validate its prediction with numerical simulations of the full system. Our results demonstrate that subradiant resonances enable the cooling of ensembles of atoms to temperatures lower than those achievable without dipole interactions, provided the atoms have different trap frequencies. Remarkably, narrow collective resonances can be sideband-resolved even when the individual atomic transition is not. In such scenarios, ground-state cooling becomes feasible solely due to light-induced dipole-dipole interactions. This approach could be utilized for future quantum technologies based on dense ensembles of emitters, and paves the way towards harnessing many-body cooperative decay for enhanced motional control.