Rabi-Kondo correlated state in a laser-driven quantum dot

Spin exchange between a single-electron charged quantum dot and itinerant electrons leads to the emergence of Kondo screening. When the quantum dot is driven resonantly by a weak laser light, the resulting emission spectrum serves as a direct probe of these correlations. In the opposite limit of vanishing exchange interaction and strong laser drive, the quantum dot exhibits coherent Rabi oscillations between the single-spin and optically excited states at the ``bare'' frequency $\Omega$. Here we show that the interplay between strong exchange and non-perturbative laser coupling leads to the formation of a new non-equilibrium quantum-correlated state, featuring a second screening cloud. We elucidate the signatures of that state in the spectrum of luminescence. The spectrum consists of a delta-function peak at the laser light frequency (the peak weight scales as $\Omega^{2/3}$) and a broad peak red-shifted by the renormalized Rabi frequency $\Omega^{*} \propto \Omega^{4/3}$. The shape of the broad peak carries detailed information about the spin screening cloud.