Quantumness of gravity in harmonically trapped particles

TL;DR

This paper explores the quantum nature of gravity using atomic interferometry, revealing how gravity's quantum or semiclassical treatment affects interference visibility and entanglement dynamics in trapped particles.

Contribution

It demonstrates that quantum gravity causes non-revivable interference patterns and entanglement between internal and external states, distinguishing it from semiclassical gravity.

Findings

Interference visibility collapses and revives for semiclassical gravity.

Non-revival of visibility indicates entanglement due to quantum gravity.

Entanglement between internal energy and source states is induced by quantum gravity.

Abstract

This study investigates the quantumness of gravity under the setup of the atomic interferometry from the viewpoint of mass-energy equivalence. We evaluated interference visibility considering a particle with internal energy levels in a harmonic trapping potential. As per the result, for a spatially superposed gravitational source mass, interference visibility exhibits collapse and revival behavior, which implies that an initial separable internal state evolves to the entangled state with respect to the degrees of freedom of the center of mass, the internal energy levels, and the external source state. In particular, it does not exhibit revival behavior when gravity is treated as a quantum interaction, while it revives with a finite period for a semiclassical treatment of gravity. We also examined the temporal behavior of entanglement negativity and found that the nonrevival behavior of visibility reflects the creation of the entanglement between the internal energy state and the external source state which is uniquely induced by the quantum interaction of gravity in accordance with the weak equivalence principle.