Matter-Mediated Entanglement in Classical Gravity: Suppression by Binding Potentials and Localization

TL;DR

This paper argues that matter-mediated entanglement in classical gravity scenarios is suppressed by binding potentials, indicating that observed entanglement does not necessarily imply quantum gravity but rather coherent matter exchange.

Contribution

It demonstrates that binding potentials in realistic macroscopic objects exponentially suppress matter-mediated entanglement, clarifying its implications for quantum gravity tests.

Findings

Binding potentials cause exponential suppression of matter-mediated entanglement.

Entanglement observed is due to matter exchange, not quantum gravity.

Suppression makes matter-mediated entanglement negligible at macroscopic scales.

Abstract

Aziz and Howl [Nature 646 (2025)] argue that two spatially separated masses can become entangled even when gravity is treated as a classical field, by invoking higher-order "virtual-matter" processes in a QFT description of matter, which is non-LOCC (local operations and classical communication). We point out that the relevant mechanism is not intrinsically field-theoretic, but is essentially a quantum tunneling/evanescent matter channel, which is already captured within ordinary quantum mechanics. More importantly, the microscopic constituents of realistic macroscopic objects are bound and localized by strong potentials, introducing a large internal energy scale that suppresses coherent propagation between distant bodies. Including such binding/localization generically yields an exponential suppression, rendering the matter-mediated contribution negligible at the macroscopic separations relevant to gravitational-entanglement proposals. Consequently, the entanglement identified by AH diagnoses the presence of a coherent matter-exchange channel rather than the classical or quantum nature of gravity, and it does not undermine LOCC-based witness arguments in realistic bound-matter platforms.