Post-Newtonian gravitational effects in optical interferometry

We investigate general optical interferometry in stationary spacetimes focusing on quantum-optical experiments in near-Earth environments. We provide a rigorous expression for the gravitationally induced phase difference and adapt the parametrized post-Newtonian formalism for calculations of polarization rotation. We investigate two optical versions of the Colella-Overhauser-Werner experiment and show that the phase difference is independent of the post-Newtonian parameter gamma, making it a possible candidate for an optical test of the Einstein equivalence principle. Polarization rotation provides an example of the quantum clock variable and, while related to the optical Lense-Thirring effects, shows a qualitatively different behavior from them.