Nonlocality via multiqubit orthogonal product bases

TL;DR

This paper explores quantum nonlocality in multiqubit orthogonal product bases, demonstrating which can be distinguished locally and revealing nonlocality without entanglement, with methods involving quantum teleportation.

Contribution

It identifies which multiqubit OPBs exhibit nonlocality without entanglement and introduces a teleportation-based method to distinguish certain nonlocal bases.

Findings

Two-qubit OPBs are locally distinguishable.

Some three and four-qubit OPBs cannot be distinguished locally.

Teleportation with Bell states can distinguish some nonlocal bases.

Abstract

We investigate the quantum nonlocality via the discrimination on two, three and four-qubit orthogonal product bases (OPBs). We show that every two-qubit, and some three and four-qubit OPBs can be locally distinguished. It turns out that the remaining three and four-qubit OPBs cannot be locally distinguished, and thus they show the quantum nonlocality without entanglement. We also distinguish them by merging some systems using quantum teleportation with assisted Bell states.