Andreev tunneling in strongly interacting quantum dots

We review recent work on resonant Andreev tunneling through a strongly interacting quantum dot connected to a normal and to a superconducting lead. We derive a general expression for the current flowing in the structure and discuss the linear and nonlinear transport in the nonperturbative regime. New effects associated with the Kondo resonance combined with the two-particle tunneling arise. The Kondo anomaly in the I-V characteristics depends on the relative size of the gap energy and the Kondo temperature. (C) 1999 Academic Press.