Charge transfer statistics and entanglement in normal-quantum dot-superconductor hybrid structures

TL;DR

This paper provides an analytical study of charge transfer and entanglement in quantum dot-superconductor systems, revealing how transport processes generate entanglement and proposing ferromagnetic electrodes as entanglement detectors.

Contribution

It offers an analytical solution for full counting statistics in quantum dot-superconductor hybrids, incorporating energy-dependent transmission and exploring entanglement detection methods.

Findings

Identification of entanglement sources via positive cross current correlations

Analytical full counting statistics solution with energy-dependent transmission

Proposal of ferromagnetic electrodes as detectors for Bell inequality violations

Abstract

We analyze the full counting statistics (FCS) of a single-site quantum dot coupled to multiple metallic electrodes in the normal state and a superconductor for arbitrary transmission. We present an analytical solution of the problem taking into account the full energy dependence of the transmission coefficient. We identify two transport processes as sources of entanglement between the current carriers by observing positive cross current correlations. Furthermore, we consider ferromagnetic electrodes and show how they can be used as detectors in experiments violating the Bell-Clauser-Horne-Shimony-Holt inequality.