Locally Mediated Entanglement in Linearized Quantum Gravity

The current interest in laboratory detection of entanglement mediated by gravity was sparked by an information-theoretic argument: entanglement mediated by a local field certifies that the field is not classical. Previous derivations of the effect modeled gravity as instantaneous; here we derive it from linearized quantum general relativity while keeping Lorentz invariance explicit, using the path-integral formalism. In this framework, entanglement is clearly mediated by a quantum feature of the field. We also point out the possibility of observing "retarded" entanglement, which cannot be explained by an instantaneous interaction. This is a difficult experiment for gravity, but is plausible for the analogous electromagnetic case.

Probing the limits of quantum theory with quantum information at subnuclear scales

Modern quantum engineering techniques enabled successful foundational tests of quantum mechanics. Yet, the universal validity of quantum postulates is an open question. Here we propose a new theoretical framework of Q-data tests, which recognizes the established validity of quantum theory, but allows for more general—‘post-quantum’—scenarios in certain physical regimes. It can accommodate a large class of models with modified quantum wave dynamics, correlations beyond entanglement or general probabilistic postulates. We discuss its experimental implementation suited to probe the nature of strong nuclear interactions. In contrast to the present accelerator experiments, it shifts the focus from high-luminosity beam physics to individual particle coherent control.