The Equivalence Principle and Quantum Mechanics

Abstract

There have been many speculations that the equivalence principle might be violated in situations involving quantum systems in a classical gravitational field. Also, several authors have stated that experiments involving quantum systems contain quantum signatures, specific to the gravitational interaction, that are fundamentally different from what could be explored in classical experiments. I critically assess these statements and prove the validity of the equivalence principle for general quantum systems in a classical gravitational field. Further, I argue that there should not be any expectation of violation of the equivalence principle in the neutrino sector. I end with some comments on a basic formulation of the equivalence principle in the quantum context.