Gravitationally Induced Entanglement Across an Event Horizon

It has long been assumed that a particle---having crossed a black hole event horizon unentangled with another particle in the exterior universe---can no longer dynamically entangle with that particle. Here, we demonstrate within a gravitational retarded-potential model that entanglement can in fact be created from scratch between freely falling spatial superpositions across an event horizon. Yet, extracting this state radially requires non-inertial deceleration, triggering soft-graviton bremsstrahlung, and establishing a strict dephasing bound in terms of entangling phase, $Γ\ge\frac{729}{160π}Φ$. This decoheres the entangled state. By contrast, equivalent macroscopic optical masses allow local tangential harvesting of entanglement via quantum erasure, thus revealing a remarkable geometric duality: Spacetime irreversibly degrades entanglement the moment the localized mass is dragged away from the horizon, while allowing the transverse teleportation of its entangled state to infinity.

Source: arXiv:2609.04104v1 - http://arxiv.org/abs/2609.04104v1 PDF: https://arxiv.org/pdf/2609.04104v1 Original Link: http://arxiv.org/abs/2609.04104v1