Effective Field Theory Approach to General Relativity and Feynman Diagrams for Coalescing Binary Systems

TL;DR

This thesis applies the Effective Field Theory approach to General Relativity, computing hereditary effects in the Post-Newtonian scheme and analyzing scattering angles in the Post-Minkowskian scheme, revealing new relevant terms.

Contribution

It introduces new calculations of hereditary effects up to 5PN order and identifies previously overlooked terms in the scattering angle analysis within EFT for GR.

Findings

Hereditary diagrams computed up to 5PN order using Feynman and Schwinger-Keldysh formalisms.

New terms found in the Post-Minkowskian scattering angle analysis that could affect physical predictions.

Comparison with existing literature confirms some results but highlights the importance of the new terms.

Abstract

In this thesis we elaborate on two different aspects of the Effective Field Theory (EFT) approach to a Binary Coalescing system in General Relativity (GR). First, we consider the issue of hereditary effects in the Post-Newtonian (PN) perturbative scheme, and we compute hereditary diagrams in the far zone region up to 5PN order, using both Feynman and Schwinger-Keldysh formalism, comparing our results with those appearing in literature. Then, we focus on the Post-Minkowskian (PM) perturbative scheme, and we compute the bending angle of a massless scalar field under the influence of a massive scalar in the EFT of GR, up to one loop order in dimensional regularisation. Our analysis points to the existence of relevant terms that were not accounted for in previous study, which may modify the predictions for physical observables.