Waiting time distributions for the transport through a quantum dot tunnel coupled to one normal and one superconducting lead

TL;DR

This paper investigates the waiting time distributions in a quantum dot system coupled to normal and superconducting leads, revealing internal dynamics and coherent Cooper pair transfer through oscillations related to Andreev bound states.

Contribution

It introduces the analysis of WTDs to study coherent transport and internal dynamics in a quantum dot with superconducting coupling, highlighting oscillations linked to Andreev states.

Findings

WTDs show oscillations related to coherent Cooper pair transfer.

Oscillation frequency matches the energy splitting of Andreev bound states.

Resonance enhances the visibility of these effects.

Abstract

We have studied the Waiting Time Distributions (WTDs) for sub-gap transport through a single-level quantum dot tunnel coupled to one normal and one superconducting lead. The WTDs reveal the internal dynamics of the system in particular the coherent transfer of Cooper pairs between the dot and the superconductor. The WTDs exhibit oscillations that can be directly associated to the coherent oscillation between the empty and doubly occupied dot. The oscillation frequency is equal to the energy splitting between the Andreev bound states. These effects are more pronounced when the empty state and double occupied state are in resonance.