Charge transport through open driven two-level systems with dissipation

We derive a Floquet-like formalism to calculate the stationary average current through an ac driven double quantum dot in the presence of dissipation. The method allows us to take into account arbitrary coupling strengths both of a time-dependent field and a bosonic environment. We numerically evaluate a truncation scheme and compare with analytical, perturbative results such as the Tien-Gordon formula.