How long does it take for the kondo effect to develop?

The time development of the Kondo effect is theoretically investigated by studying a quantum dot suddenly shifted into the Kondo regime by a change of voltage on a nearby gate. Using time-dependent versions of both the Anderson and Kondo Hamiltonians, it is shown that after a time tfollowing the voltage shift, the form of the Kondo resonance matches the time-independent resonance at an effective temperature T_eff = T/tanh(πTt/2). Relevance of the buildup of the Kondo resonance to the transport current through a quantum dot is demonstrated.