Sagnac Interferometer and the Quantum Nature of Gravity

Understand

We use a quantum variant of the Sagnac interferometer to argue for the quantum nature of gravity as well as to formulate a quantum version of the equivalence principle.

• We first present an original derivation of the phase acquired in the conventional Sagnac matter-wave interferometer, within the Hamiltonian formalism.
• Then we modify the interferometer in two crucial respects.
• The interfering matter wave is interfered along two different distances from the centre and the interferometer is prepared in a superposition of two different angular velocities.