Gravitationally-induced conversion of local coherence to entanglement

In recent years, the quantum nature of gravity has attracted significant attention as one of the most important problems in modern physics. In this work, we investigate the gravity-mediated entanglement protocol proposed by Bose et al. from the perspective of quantum resource theory. Within this framework, the gravitational interaction is described by a diagonal unitary evolution that redistributes quantum resources between local coherence and bipartite entanglement. Specifically, we show that, within this protocol, bipartite entanglement is generated through the conversion of initial local coherence into shared nonlocal quantum correlations. We obtain explicit analytical complementarity relations that characterize this coherence–entanglement trade-off and illustrate these analytical results numerically. Furthermore, we demonstrate that the amount of entanglement generated is bounded by the initial coherence of the subsystems. In particular, initial local coherence is a necessary resource for entanglement generation, while maximal entanglement is attainable only when both subsystems are initially maximally coherent.