Testing quantum aspects of Linearized Gravity in a Lab

Understanding linearized aspects of gravity in the framework of quantum mechanics is one of the great challenges in modern physics.

Along this line, a prime question is to find whether the linearized gravity is a quantum entity subject to the rules of quantum mechanics. Here, I will introduce an idea for such a test based on the principle that two objects cannot be entangled without a quantum mediator. We show that despite the weakness of gravity, the phase evolution induced by the gravitational interaction of two micron size test masses in adjacent matter-wave interferometers can detectably entangle them even when they are placed far apart enough to keep Casimir-Polder forces at bay. I will discuss the prescription for witnessing this entanglement, which certifies gravity as a quantum off-shell mediator, through simple correlation measurements between two spins: one embedded in each test mass. I will discuss how this experiment can place a potential constraint on the nature of gravity at short distances as well.