Asymptotic symmetries and infrared phenomena in gauge theories and gravity

Abstract

The objective of the following dissertation is to present the existent connection in the infrared regime behavior of both gauge theories and gravity. The first element in this picture analysis is the study of soft theorems, originally developed by Weinberg [1][2]. In a general sense, scattering processes are governed through constraints that control the way soft particles are produced. The second one shall be the asymptotic spacetime symmetries developed by Bondi, van der Burg, Metzner and Sachs [3] [4] of asymptotically flat spacetimes. They lead to the appearance of conserved charges associated to the behavior of the fields at null infinities. The third but not least, the existence of memory effects, like the ones studied by Christodolou [5][6] and Thorne [7] in the infrared limit. Again, in simple terms, they refer to the surgence of perturbations in the fabric of spacetime due to its propagation, leading to field shifts. We explore the connection in terms of the application of Fourier transforms and Ward identities. For simplicity we focus on the case of Quantum Electrodynamics and Quantum Gravity.