Is Gravity Quantum?

Understand

What gravitational field is generated by a massive quantum system in a spatial superposition? This is one of the most important questions in modern physics, and after decades of intensive theoretical and experimental research, we still do not know the answer.

• On the experimental side, the difficulty lies in the fact that gravity is weak and requires large masses to be detectable.
• But for large masses, it becomes increasingly difficult to generate spatial quantum superpositions, which live sufficiently long to be detected.
• A delicate balance between opposite quantum and gravitational demands is needed.