Can classical theories of gravity produce entanglement?

TL;DR

The paper argues that classical gravity cannot generate quantum entanglement, countering recent claims by showing that the observed entanglement results from discarded transition amplitudes.

Contribution

It clarifies that classical gravitational interactions do not produce entanglement when all transition amplitudes are properly considered.

Findings

Classical gravity does not generate entanglement in the analyzed scenario.

Discarding transition amplitudes leads to the false appearance of entanglement.

Proper inclusion of all amplitudes shows the state remains factorized over time.

Abstract

A recent paper published on Nature [Nature,646,813(2025)] by Aziz and Howl, claims that quantum particles become entangled when they interact gravitationally, even if the gravitational potential is treated classically. We show that the entanglement found by the authors stems from discarding some of the transition amplitudes, which, when kept, guarantee that an initially factorized state remains so over time. Therefore, no entanglement is generated by the classical gravitational interaction in the scenario considered by the authors.