Locally mediated entanglement through gravity from first principles

Locally mediated entanglement through gravity from first principles

Marios Christodoulou, Andrea Di Biagio, Markus Aspelmeyer, Časlav Brukner, Carlo Rovelli, Richard Howl
Institute for Quantum Optics and Quantum Information, Vienna & The Centre de Physique Théorique – UMR 7332 – CNRS and Aix-Marseille Université and Université de Toulon & The University of Western Ontario and Rotman Institute for Philosophy & Perimeter Institute for Theoretical Physics & Royal Holloway




Observing entanglement generation mediated by a local field certifies that the field cannot be classical. This information-theoretic argument is at the heart of the race to observe gravity-mediated entanglement in a `table-top' experiment. Previous derivations of the effect assume the locality of interactions, while using an instantaneous interaction to derive the effect. We correct this by giving a first principles derivation of mediated entanglement using linearised gravity. The framework is Lorentz covariant -- thus local -- and yields Lorentz and gauge invariant expressions for the relevant quantum observables. For completeness we also cover the electromagnetic case. An experimental consequence of our analysis is the possibility to observe *retarded* mediated entanglement, which avoids the need of taking relativistic locality as an assumption. This is a difficult experiment for gravity, but could be feasible for electromagnetism. Our results confirm that the entanglement is dynamically mediated by the gravitational field.