Localization control of few-photon states in parity-symmetric photonic molecules under balanced pumping

TL;DR

This paper explores how quantum feedback can control photon localization in symmetric photonic molecules, revealing that coupling can enhance asymmetry and that these effects are robust against imperfections.

Contribution

It introduces a feedback mechanism that induces asymmetric photon populations in parity-symmetric systems while maintaining balanced pumping.

Findings

Quantum feedback induces asymmetry in photon populations.

Coupling can enhance localization asymmetry.

Results are robust against detection inefficiencies.

Abstract

We theoretically investigate the problem of localization control of few-photon states in driven-dissipative parity-symmetric photonic molecules. We show that a quantum feedback loop can utilize the information of the spontaneously-emitted photons from each cavity to induce asymmetric photon population in the system, while maintaining a balanced pump that respects parity symmetry. To better understand the system's behaviour, we characterize the degree of asymmetry as a function of the coupling between the two optical cavities. Contrary to intuitive expectations, we find that in some regimes the coupling can enhance the population asymmetry. We also show that these results are robust against experimental imperfections and limitations such as detection efficiency.