Using an atom interferometer to infer gravitational entanglement generation

TL;DR

This paper proposes a novel quantum sensing protocol to test if gravitational interactions can generate entanglement between massive objects, potentially providing evidence for quantized gravity effects.

Contribution

It introduces interactive quantum information sensing as a new method to verify weak dynamical entanglement generation due to gravity, with robustness to thermal noise.

Findings

Protocol is highly robust to thermal noise

Sensitivity can be enhanced with initial thermal states or non-gravitational entanglement

Preliminary estimates suggest near-term feasibility of the experiment

Abstract

If gravitational perturbations are quantized into gravitons in analogy with the electromagnetic field and photons, the resulting graviton interactions should lead to an entangling interaction between massive objects. We suggest a test of this prediction. To do this, we introduce the concept of interactive quantum information sensing. This novel sensing protocol is tailored to provable verification of weak dynamical entanglement generation between a pair of systems. We show that this protocol is highly robust to typical thermal noise sources. The sensitivity can moreover be increased both using an initial thermal state and/or an initial phase of entangling via a non-gravitational interaction. We outline a concrete implementation testing the ability of the gravitational field to generate entanglement between an atomic interferometer and mechanical oscillator. Preliminary numerical estimates suggest that near-term devices could feasibly be used to perform the experiment.