QI In the literature: contested

Does gravity-mediated entanglement prove the gravitational field is quantum?

In plain words

The standard argument says a classical go-between cannot create entanglement, so seeing it would prove gravity quantum. A 2025 paper argues that classical gravity acting on quantum matter fields can still create some entanglement through virtual matter particles (short-lived intermediate states), so the inference is disputed.

Precise statement

The LOCC argument (local operations and classical communication cannot create entanglement) assumes the gravitational mediator acts as a classical channel. Determine under which explicit assumptions (locality, field-theoretic matter, linearity) observed entanglement at the rate $\phi = G m^2 t/(\hbar d)$ excludes classical gravity, and compute the entanglement producible by semiclassical or stochastic classical gravity coupled to quantum-field matter, which Aziz and Howl find enters at higher order in G and grows with mass toward the Planck mass (about 2e-5 g).

What would settle it

A theorem stating which classes of classical gravity models a given entanglement measurement excludes, with parameter regimes where classical contributions are provably negligible.

Status in the literature

Unverified note

Aziz and Howl (Nature 2025, arXiv:2510.19714) argued that classical gravity with quantum-field matter produces entanglement, reopening the interpretation of the proposed experiments.