Down-conversion processes in <i>ab initio</i> nonrelativistic quantum electrodynamics

The availability of efficient photon sources with specific properties is important for quantum-technological applications. However, the realization such often challenging and hence alternative perspectives that suggest different means to enhance desired while suppressing detrimental processes are valuable. In this work we highlight ab initio simulations coupled light-matter systems can provide avenues. We show a simple model quantum ring by treating light matter on equal footing, create pathways down-conversion processes. By changing subsystem as well photonic environment in experimentally feasible ways, engineer hybrid states at same time efficiency process nonclassicality created photons. Furthermore, also leads faster down-conversion, potentially avoiding decoherence effects.