No oscillating subradiant correlations in a strongly driven quantum emitter array

Abstract

We theoretically study time-dependent correlations in a strongly driven array of $N$ two-level atoms, coupled to photons in a waveguide. We focus on the spectrum $\{λ\}$ of the Liouvillian superoperator, which determines the correlation decay rates $-\Re λ$ and the frequencies $\Imλ$. Our main finding is the suppression of subradiant oscillating correlations between atomic states by a strong coherent drive of amplitude $Ω$: $|\Re λ|\ge mγ/2$, where $γ$ is the single-atom spontaneous decay rate and $m=|\Im λ/(2Ω)|$ is a nonzero integer for correlations oscillating in time $\propto \exp(\pm 2i m|Ω| t)$. This limit is independent of the number of atoms $N$; it holds both for small arrays and in the macroscopic limit. We demonstrate the suppression of subradiance numerically and provide a rigorous proof based on the analytical decomposition of the Liouvillian using spectral theory of simplicial complexes and posets.