A theory of the Kondo effect in quantum dots at zero temperature in the presence of arbitrarily intense ac potentials is presented. We generalize the Friedel-Langreth sum rule to take care of charge conservation and propose a consistent procedure to study a time-dependent Anderson Hamiltonian. The effect of the ac potential on both the quantum dot density of states and the linear conductance shows the importance of using a theory which describes intradot finite interaction and nonperturbative effects.

• Received 22 July 1998

DOI:https://doi.org/10.1103/PhysRevLett.81.4688