Master equation for a quantum system driven by a strong periodic field in the quasienergy representation

The evolution of a quantum system weakly coupled with a thermal reservoir and influenced by an external periodic field is formulated in the quasienergy representation where the strong external periodic field disappears and the original model is transformed to a time-dependent system weakly coupled with thermal reservoir. Based on this time-dependent subdynamics, we derive a master equation of the reduced density operator for the driven quantum system. This equation is valid in the weak-coupling limit. Our method can be useful for obtaining the master equation of any system coupled with a thermal reservoir and driven by strong external periodic fields.