Charge-Kondo effect in mesoscopic superconductors coupled to normal metals

We develop a theoretical proposal for the charge-Kondo effect in mesoscopic normal-superconductor-normal heterostructures, where the superconducting gap exceeds the electrostatic charging energy. Charge-Kondo correlations in these devices alter the conventional temperature dependence of Andreev reflection and electron cotunneling. We predict typical Kondo temperatures of greater than or similar to 10 mK, and suggest experimental architectures that combine superconducting charge qubits with semiconducting nanowires at cryogenic temperatures.