Strong Tunneling in Small Quantum Dots: Kondo E ect in Two Model Systems

We study electron transport through single and double quantum dots with large level spacing and charging energy. Motivated by recent experiments we focus on linear and nonlinear response of two model systems: a single dot with two levels and a capacitively coupled double dot. At low temperature and strong coupling to the leads, quantum uctuations and Kondo-like many-body eeects become important and show up, e.g., as resonances in the current-voltage characteristics. In particular, we propose a way to observe the splitting of the Kondo peak as a function of the applied bias voltage.