Self-testing nonlocality without entanglement
Ivan Šupić, Nicolas Brunner · Physical Review A · 2023
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 that is robust to noise. This result also demonstrates that genuine network quantum nonlocality can be obtained using only nonentangled measurements. From a more general perspective, our work establishes a connection between the effect of nonlocality without entanglement and the area of Bell nonlocality.