On the Role of Locality in the Bose-Marletto-Vedral Effect

TL;DR

This paper examines how the assumption of locality influences the validity of an entanglement-based test for non-classicality in quantum gravity, specifically in the context of the Bose-Marletto-Vedral effect.

Contribution

It analyzes the role of locality assumptions in the theorem supporting the entanglement witness for quantum gravity effects.

Findings

Locality assumptions are crucial for the theorem's validity.

Different notions of locality are discussed and compared.

The paper clarifies the conceptual foundations of the entanglement witness.

Abstract

Two of us recently proposed an entanglement-based witness of non-classicality, which can be applied to testing quantum effects in gravity in what is known as the Bose-Marletto-Vedral (BMV) effect. The witness is based on this idea: if a system can create entanglement between two quantum probes by local means only, then it must be non-classical. In this note we discuss the role of locality as an assumption for the theorem supporting the witness; we also discuss other related notions of locality and comment on their mutual relations.