Noise in superconductor-quantum dot-normal metal structures in the Kondo regime

TL;DR

This paper investigates noise characteristics in a superconductor-quantum dot-normal metal junction within the Kondo regime, revealing a universal Fano factor of 10/3 below the superconducting gap and analyzing many-body effects on current and noise.

Contribution

It introduces a generalized concept of Kondo resonance floating and calculates many-body corrections to subgap current and noise in the specified junction.

Findings

Fano factor remains at 10/3 for voltages below the gap

Many-body corrections significantly affect subgap current

Implications for finite frequency noise are discussed

Abstract

We consider a N-dot-S junction in the Kondo regime in the limit where the superconducting gap is much smaller than the Kondo temperature. A generalization of the floating of the Kondo resonance is proposed and many body corrections to the average subgap current are calculated. The zero frequency noise is computed and the Fano factor sticks to the value 10/3 for all voltages below the gap. Implications for finite frequency noise are briefly discussed.