Signatures of the quantum nature of gravity in the differential motion of two masses

Understand

We show that a signature of the quantum nature of gravity is the quantum mechanical squeezing of the differential motion of two identical masses with respect to their common mode.

• This is because the gravitational interaction depends solely on the relative position of the two masses.
• In principle, this squeezing is equivalent to quantum entanglement between the masses.
• In practice, detecting the squeezing is more feasible than detecting the entanglement.