Previous derivations of the effect modeled gravity as instantaneous. Such an approach neglects relativistic locality, which implies that the gravitational interaction is not instantaneous. We provide an explicitly Lorentz invariant description of gravity-induced entanglement within linearized quantum gravity using the path-integral formalism. In this formalism the effect is due to a genuinely quantum feature of the gravitational field: the possibility to be in a quantum superposition of distinct semiclassical configurations. This implies that, in the context of linearized quantum gravity, entanglement arises due to a quantum superposition of spacetimes, each propagating information causally. Information travels in a quantum superposition of wave fronts in the field and entanglement starts being generated only after a light crossing time has elapsed. We point out the possibility of observing “retarded” entanglement, which cannot be explained by an instantaneous interaction.
Publication in Physical Review Letters:
Marios Christodoulou, Andrea Di Biagio, Markus Aspelmeyer, Časlav Brukner, Carlo Rovelli, Richard Howl
“Locally Mediated Entanglement in Linearized Quantum Gravity”
