The Charge in a Lift. A Covariance Problem

We analyze the classical problemof a charge that falls in a gravitational field, Einstein’s famous Gedankenexperiment. The goal of this paper is to analyze an original approach developed by Soker and Harpaz (2000) based on what we have called Larmor “whiplash”. The authors consider the case of a charge freely falling in a uniform gravitational field and the case of a charge supported at rest in a gravitational field. Instead, starting from Thomson’s geometrical proof of the Larmor relation, we consider the case of a freely falling charge in a “real” gravitational field. In this case, we believe that tidal effects are present, and the charge will radiate. We also make some reflections about the equivalence principle, understood as general covariance, and about the metric construction according to Fock.