On the possibility of laboratory evidence for quantum superposition of geometries

Understand

We analyze the recent proposal of measuring a quantum gravity phenomenon in the lab by entangling two particles gravitationally.

• We give a generally covariant description of this phenomenon, where the relevant effect turns out to be a quantum superposition of proper times.
• We point out that measurement of this effect would count as evidence for quantum superposition of spacetime geometries.
• This interpretation addresses objections appeared in the literature.