Transport through a single Anderson impurity coupled to one normal and two superconducting leads

TL;DR

This paper investigates the complex interplay between Kondo and Andreev-Josephson effects in a quantum dot system with one normal and two superconducting leads, revealing a crossover between different quantum states.

Contribution

It provides an exact low-energy description of the system in the large gap limit and analyzes the phase-dependent crossover using numerical renormalization group methods.

Findings

Identification of phase-dependent renormalized parameters

Characterization of the crossover between Kondo and Cooper-pairing states

Exact description of low-energy states in the large gap limit

Abstract

We study the interplay between the Kondo and Andreev-Josephson effects in a quantum dot coupled to one normal and two superconducting (SC) leads. In the large gap limit, the low-energy states of this system can be described exactly by a local Fermi liquid for the interacting Bogoliubov particles. The phase shift and the renormalized parameters for the Bogoliubov particles vary depending on the Josephson phase between the two SC leads. We explore the precise features of a crossover that occurs between the Kondo singlet and local Cooper-pairing states as the Josephson phase varies, using the numerical renormalization group approach.