  We show that it is possible to realize quantum superpositions of switched-on
and -off strong light-matter interaction in a single quantum dot- semiconductor
microcavity system. Such superpositions enable the observation of
counterintuitive quantum conditional dynamics effects. Situations are possible
where cavity photons as well as the emitter luminescence display exponential
decay but their joint detection probability exhibits vacuum Rabi oscillations.
Remarkably, these quantum correlations are also present in the nonequilibrium
steady state spectra of such coherently driven dissipative quantum systems.
