How to avoid the appearance of a classical world in gravity experiments

Abstract

Quantum states of gravitational source masses can lead to experimental outcomes that are inconsistent with the predictions of a purely classical field theory of gravity. Environmental decoherence places strict boundary conditions to the potential realization of such experiments: sufficiently mild not to act as a fundamental show-stopper, yet sufficiently demanding to represent a formidable challenge to the next generation of quantum experiment(er)s.

dedicated to Dieter Zeh; to appear in: "From Quantum to Classical. Essays in memory of H.-Dieter Zeh", Fundamental Theories of Physics, edited by Claus Kiefer, Springer 2022