Graph connectivity based strong quantum nonlocality with genuine entanglement

TL;DR

This paper constructs genuinely entangled quantum state sets exhibiting strong nonlocality by linking their properties to graph connectivity, providing a negative answer to previous open questions in quantum nonlocality research.

Contribution

It introduces a novel method connecting graph connectivity with strong nonlocality in genuinely entangled states, solving an open problem in the field.

Findings

Constructed genuinely entangled sets with strong nonlocality.

Established a relation between quantum nonlocality and graph connectivity.

Provided a negative answer to the existence of strongly nonlocal entangled sets.

Abstract

Strong nonlocality based on local distinguishability is a stronger form of quantum nonlocality recently introduced in multipartite quantum systems: an orthogonal set of multipartite quantum states is said to be of strong nonlocality if it is locally irreducible for every bipartition of the subsystems. Most of the known results are limited to sets with product states. Shi et al. presented the first result of strongly nonlocal entangled sets in [Phys. Rev. A 102, 042202 (2020)] and there they questioned the existence of strongly nonlocal set with genuine entanglement. In this work, we relate the strong nonlocality of some speical set of genuine entanglement to the connectivities of some graphs. Using this relation, we successfully construct sets of genuinely entangled states with strong nonlocality. As a consequence, our constructions give a negative answer to Shi et al.'s question, which also provide another answer to the open problem raised by Halder et al. [Phys. Rev. Lett. 122, 040403 (2019)]. This work associates a physical quantity named strong nonlocality with a mathematical quantity called graph connectivity.