Violating Bell's inequality with remotely-connected superconducting qubits

TL;DR

This paper demonstrates a robust superconducting system capable of deterministically violating Bell's inequality, a key benchmark for quantum entanglement, advancing quantum communication technology.

Contribution

The authors present a simple, robust architecture that achieves deterministic Bell inequality violation in superconducting qubits, a milestone in quantum communication.

Findings

Deterministic violation of Bell's inequality achieved in superconducting qubits.

Architecture enables fast and accurate control of entangling photon emission.

Advances the development of secure quantum communication systems.

Abstract

Quantum communication relies on the efficient generation of entanglement between remote quantum nodes, due to entanglement's key role in achieving and verifying secure communications. Remote entanglement has been realized using a number of different probabilistic schemes, but deterministic remote entanglement has only recently been demonstrated, using a variety of superconducting circuit approaches. However, the deterministic violation of a Bell inequality, a strong measure of quantum correlation, has not to date been demonstrated in a superconducting quantum communication architecture, in part because achieving sufficiently strong correlation requires fast and accurate control of the emission and capture of the entangling photons. Here we present a simple and robust architecture for achieving this benchmark result in a superconducting system.