A proposed experiment could bring scientists closer to answering the long-standing question of whether gravity is a classical or a quantum phenomenon. If gravity is intrinsically quantum, the mutual gravitational attraction between the two objects could cause them to become entangled.

A proposed experiment could bring scientists closer to answering the long-standing question of whether gravity is a classical or a quantum phenomenon. If gravity is intrinsically quantum, the mutual gravitational attraction between the two objects could cause them to become entangled.

https://physics.aps.org/articles/v17/65