Real-time observation of Cooper pair splitting showing strong non-local correlations

TL;DR

This paper reports the first real-time observation of individual Cooper pair splitting, demonstrating high-fidelity detection of entangled electrons and enabling future quantum entanglement experiments.

Contribution

It introduces a novel real-time measurement technique for individual Cooper pair splitting with 99% fidelity, addressing a key challenge in quantum entanglement research.

Findings

Detected a peak in correlation statistics two orders of magnitude above background

Achieved 99% fidelity in identifying split Cooper pairs

Enabled direct access to time-resolved statistics of Cooper pair splitting

Abstract

Controlled generation and detection of quantum entanglement between spatially separated particles constitute an essential prerequisite both for testing the foundations of quantum mechanics and for realizing future quantum technologies. Splitting of Cooper pairs from a superconductor provides entangled electrons at separate locations. However, experimentally accessing the individual split Cooper pairs constitutes a major unresolved issue as they mix together with electrons from competing processes. Here, we overcome this challenge with the first real-time observation of the splitting of individual Cooper pairs, enabling direct access to the time-resolved statistics of Cooper pair splitting. We determine the correlation statistics arising from two-electron processes and find a pronounced peak that is two orders of magnitude larger than the background. Our experiment thereby allows to unambiguously pinpoint and select split Cooper pairs with 99 % fidelity. These results open up an avenue for performing experiments that tap into the spin-entanglement of split Cooper pairs.