Modeling Compact Objects with EFT II: The Post-Newtonian Expansion

Abstract: Part 2 of 3 from master's thesis: Modeling Compact Objects with Effective Field Theory. Using the Effective Field Theory framework for extended objects, we build the effective theory of a binary system made up of the most general compact objects in a theory of gravity as General Relativity with electrodynamics, objects which are described by their mass, spin, charge and their finite-size structure. We obtain the leading order post-Newtonian expansion to each of the relevant terms in the effective action that have been derived using the coset construction, where the covariant building blocks to build up the tower of invariant operators are derived from symmetry principles. Having matched the coefficients of the theory from the literature, we show the predictivity of our theory by obtaining well known post-Newtonian results on spinning extended objects, as well as on charged objects. Then, we bring new results on the polarizability and dissipation of charged spinning compact objects.