Charge-Kondo Effect in Mesoscopic Superconductors Coupled to Normal Metals

TL;DR

This paper proposes a theoretical framework for observing the charge Kondo effect in mesoscopic normal-superconductor heterostructures, predicting unique temperature-dependent behaviors and suggesting experimental setups involving superconducting charge qubits and nanowires.

Contribution

It introduces a novel theoretical model for the charge Kondo effect in mesoscopic superconducting systems where the superconducting gap exceeds charging energy.

Findings

Charge-Kondo correlations modify Andreev reflection and cotunneling.

Predicted Kondo temperatures are greater than 10 mK.

Experimental architectures combining superconducting qubits and nanowires are proposed.

Abstract

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 $\gtrsim 10 {\rm mK}$, and suggest experimental architectures that combine superconducting charge-qubits with semiconducting nanowires at cryogenic temperatures.