Self-testing nonlocality without entanglement

TL;DR

This paper demonstrates that nonlocality without entanglement can be certified in a device-independent way using a simple quantum network, linking it to Bell nonlocality.

Contribution

It introduces a self-testing method for nonlocality without entanglement, showing genuine network quantum nonlocality with only non-entangled measurements.

Findings

Nonlocality without entanglement can be certified device-independently.

A simple quantum network suffices to demonstrate this nonlocality.

The work connects nonlocality without entanglement to Bell nonlocality.

Abstract

Quantum theory allows for nonlocality without entanglement. Notably, there exist bipartite quantum measurements consisting of only product eigenstates, yet they cannot be implemented via local quantum operations and classical communication. In the present work, we show that a measurement exhibiting nonlocality without entanglement can be certified in a device-independent manner. Specifically, we consider a simple quantum network and construct a self-testing procedure. This result also demonstrates that genuine network quantum nonlocality can be obtained using only non-entangled measurements. From a more general perspective, our work establishes a connection between the effect of nonlocality without entanglement and the area of Bell nonlocality.