Prof Vlatko Vedral FInstP

Abstract:

It is known that an entanglement-based witness of nonclassicality can be applied to testing quantum effects in gravity. Specifically, if a system can create entanglement between two quantum probes by local means only, then it must be nonclassical. Recently, claims have been made that collapse-based models of classical gravity, i.e., Diósi-Penrose model, can predict gravitationally induced entanglement between quantum objects, resulting in gravitationally induced entanglement is insufficient to conclude that gravity is fundamentally quantum, contrary to the witness statement. Here, we vindicate the witness. We analyze the underlying physics of collapse-based models for gravity and show that these models have nonlocal features, violating the assumption of locality. We suggest that the entanglement can be generated through quantumlike hidden detectors without interaction with the gravitational field.