Noisy metamolecule: strong narrowing of fluorescence line

We consider metamolecule consisting of bosonic mode correlated with the two-level system: it can be, for example, plasmonic mode interacting with the quantum dot. We focus on the parameter range where all the correlations are strong and of the same order: interaction between bosonic mode correlated with the two-level system, external coherent drive and dissipation. Quantum Monte-Carlo simulations show a fluorescence of this system at dissipation larger than the driving amplitude and strong (by the order of magnitude) narrowing of its spectral line. This effect may be related to kind of a quantum stochastic resonance. We show that the fluorescence corresponds to finite domain over the coherent drive with sharp lower threshold and there is splitting of the Wigner function.