Gravity-induced phase-shift of light: outline of an interferometric test of the Equivalence Principle

Abstract

I analyze the change of the interference pattern in an optical interferometer when it passes from rest to free fall. It is shown that the "disconnection" of the gravitational field causes a jump in the phase difference that could be measured with the current sensitivity of these instruments. For this reason, I propose to the optical interferometry community the possibility of a test of the Equivalence Principle based on the aforementioned effect.