Entangling electrons by splitting Cooper pairs: Two-particle conductance resonance and time coincidence measurements

TL;DR

This paper demonstrates a highly efficient method to split Cooper pairs in a superconductor-nanowire device, providing evidence of entangled electrons through conductance and shot noise measurements, advancing quantum information processing.

Contribution

It introduces a novel electron splitter device that achieves high Cooper pair splitting efficiency and confirms entanglement via conductance and shot noise analysis.

Findings

High-efficiency Cooper pair splitting observed

Positive conductance and shot noise correlations confirmed entanglement

Shot noise measurements verified quasiparticle charge

Abstract

Entanglement, being at the heart of the Einstein-Podolsky-Rosen (EPR) paradox, is a necessary ingredient in processing quantum information. Cooper pairs in superconductors - being composites of two fully entangled electrons - can be split adiabatically, thus forming entangled electrons. We fabricated such electron splitter by contacting an aluminum superconductor strip at the center of a suspended InAs nanowire; terminated at both ends with two normal metallic drains. Intercepting each half of the nanowire by gate - induced Coulomb blockaded quantum dot strongly impeded the flow of Cooper pairs due to large charging energy, while still permitting passage of single electrons. Here, we provide conclusive evidence of extremely high efficiency Cooper pairs splitting via observing positive average (conductance) and time (shot noise) correlations of the split electrons in the two opposite drains of the nanowire. Moreover, The actual charge of the injected quasiparticles was verified by shot noise measurements.