Strongly subradiant states in planar atomic arrays

TL;DR

This paper theoretically investigates collective dipolar oscillations in finite planar atomic arrays, revealing mechanisms that produce strongly subradiant states with significantly extended lifetimes, especially in square arrays.

Contribution

It identifies how array symmetry and dispersion properties enhance subradiance, demonstrating that square arrays support states with radiative losses decreasing as N^{-5}.

Findings

Square atomic arrays support eigenstates with minimal radiative losses.

Radiative lifetime of subradiant states scales as N^{-5} with the number of atoms.

External coupling and array symmetry are key to enhancing subradiance.

Abstract

The optically trapped ensembles of atoms provide a versatile platform for storing and coherent manipulation of quantum information. However, efficient realization of quantum information processing requires long-lived quantum states protected from the decoherence e.g. via spontaneous emission. Here, we theoretically study collective dipolar oscillations in finite planar arrays of quantum emitters in free space and analyze mechanisms that govern the emergence of strongly subradiant collective states. We demonstrate that the external coupling between the collective states associated with the symmetry of the array and with the quasi-flat dispersion of the corresponding infinite lattice plays a crucial role in the boost of their radiative lifetime. We show that among different regular arrangements of the atoms the square atomic arrays support eigenstates with minimal radiative losses that scale with the total number of atoms $N_{tot}$ as $\propto N_{tot}^{-5}$.