Existing experiments suffice to indirectly verify the quantum essence of gravity

TL;DR

Current matter-wave interferometers can indirectly demonstrate that gravity induces entanglement between quantum systems, supporting the quantum nature of gravity without requiring technologically unfeasible experiments.

Contribution

The paper shows that verifying the Schrödinger equation for a single system under gravity suffices to imply gravity-mediated entanglement between two systems.

Findings

Matter-wave interferometers can indirectly verify gravitational entanglement.

Verifying Schrödinger evolution for one system implies entanglement for two.

Supports quantum nature of gravity with current experimental capabilities.

Abstract

The gravity-mediated entanglement experiments employ concepts from quantum information to argue that if entanglement due to gravitational interaction is observed, then gravity cannot be described by a classical system. However, the proposed experiments remain beyond our current technological capability, with optimistic projections placing the experiment outside of the short-term future. Here we argue that current matter-wave interferometers are sufficient to indirectly prove that gravitational interaction creates entanglement between two systems. Specifically, we prove that if we experimentally verify the Schr\"odinger equation for a single delocalized system interacting gravitationally with an external mass, then, under one of two reasonable assumptions, the time evolution of two delocalized systems will lead to gravity-mediated entanglement.