In a new Physical Review Letters study, researchers propose an experimental approach that could finally determine whether gravity is fundamentally classical or quantum in nature.

The nature of gravity has puzzled physicists for decades. Gravity is one of the four fundamental forces, but it has resisted integration into the quantum framework, unlike the electromagnetic, strong, and weak nuclear forces.

Rather than directly tackling the challenging problem of constructing a complete quantum theory of gravity or trying to detect individual gravitons—the hypothetical mediator of gravity—the researchers take a different approach.