Probing ultrastrong light–matter coupling in open quantum systems

Dynamically probing systems of ultrastrongly coupled light and matter by advanced coherent control have been recently proposed as a unique tool for detecting peculiar quantum features of this regime. Coherence allows in principle on-demand conversion of virtual photons dressing the entangled eigenstates of the system to real ones, with unitary efficiency and remarkable robustness. Here, we study this effect in the presence of decoherence, showing that also in far from ideal regimes is it possible to probe such peculiar features.