  We show that the probability distribution of the stationary state of a
dissipative ac-driven two-level system exhibits discontinuities, i.e. jumps,
for parameters at which coherent destruction of tunneling takes place. These
discontinuities can be observed as jumps in the emission of the Mollow triplet.
The jumps are the consequence of discontinuities in the transition rates, which
we calculate numerically and analytically based on the secular Floquet-Redfield
formalism.
