Energy and entropy in the geometrical trinity of gravity
Débora Aguiar Gomes, Jose Beltrán Jiménez, Tomi Koivisto
Abstract
All energy is gravitational energy. That is the consequence of the equivalence principle, according to which gravity is the universal interaction. The physical charges of this interaction have remained undisclosed, but the advent of the geometrical trinity opened a new approach to this foundational problem. Here it is shown to provide a background-independent unification of the previous, noncovariant approaches of Bergmann-Thomson, Cooperstock, Einstein, von Freud, Landau-Lifshitz, Papapetrou, and Weinberg. First, the Noether currents are derived for a generic Palatini theory of gravity coupled with generic matter fields, and then the canonical, i.e., the unique charges, are robustly derived and analyzed, particularly in the metric teleparallel and the symmetric teleparallel versions of general Relativity. These results, and their application to black holes and gravitational waves, are new.