Partial Self-Testing and Randomness Certification in the Triangle Network

Quantum nonlocality can be demonstrated without inputs (i.e., each party using a fixed measurement setting) in a network with independent sources. Here we consider this effect on ring networks, and show that the underlying quantum strategy can be partially characterized, or self-tested, from observed correlations. Applying these results to the triangle network allows us to show that the nonlocal distribution of Renou et al. [Phys. Rev. Lett. 123, 140401 (2019)] requires that (i) all sources produce a minimal amount of entanglement, (ii) all local measurements are entangled, and (iii) each local outcome features a minimal entropy. Hence we show that the triangle network allows for genuine network quantum nonlocality and certifiable randomness.

Automated summary

This study investigates the demonstration of quantum nonlocality in networks with independent sources and proposes a method for self-testing the underlying quantum strategy. By applying these findings to the triangle network, the researchers show that the network exhibits genuine network quantum nonlocality and certifiable randomness.