Quantum-gravity effects could in principle be witnessed in neutrino-like oscillations

TL;DR

This paper proposes a theoretical scheme where gravitational interactions between particles in superposition states could reveal quantum gravity effects through entanglement, similar to neutrino oscillations.

Contribution

It introduces a novel variant of a gravitational entanglement scheme involving particles in superpositions of different masses, extending previous work.

Findings

The scheme demonstrates how gravitationally mediated entanglement can be observed without direct measurement.

It suggests that neutrino-like particles could be used to witness quantum gravity effects.

The approach provides a new perspective on testing quantum gravity through particle superpositions.

Abstract

Two of us (CM and VV) recently showed how the quantum character of a physical system, in particular the gravitational field, can in principle be witnessed without directly measuring observables of that system, solely by its ability to mediate entanglement between two other systems. Here we propose a variant of that scheme, where the entanglement is again generated via gravitational interaction, but now between two particles both at sharp locations (very close to each other) but each in a superposition of two different masses. We discuss an in-principle example using two hypothetical massive, neutral, weakly-interacting particles generated in a superposition of different masses. The key property of such particles would be that, like neutrinos, they are affected only by weak nuclear interactions and gravity.