Scattering Amplitude Techniques in Classical Gauge Theories and Gravity

TL;DR

This thesis explores how modern scattering amplitude techniques can be applied to compute classical observables in gauge theories and gravity, including spin effects, wave scattering, and the double copy formalism, with implications for black hole physics.

Contribution

It introduces novel applications of amplitude methods to classical two-body problems, incorporating spin effects and the double copy in a comprehensive framework.

Findings

Computed classical impulse and waveforms using amplitude techniques.

Analyzed the role of soft theorems in classical radiation.

Linked gravitational Compton amplitudes to black hole scattering.

Abstract

In this thesis we present a study of the computation of classical observables in gauge theories and gravity directly from scattering amplitudes. In particular, we discuss the direct application of modern amplitude techniques in the one, and two-body problems for both, scattering and bounded scenarios, and in both, classical electrodynamics and gravity, with particular emphasis on spin effects in general, and in four spacetime dimensions. Among these observables we have the conservative linear impulse and the radiated waveform in the two-body problem, and the differential cross section for the scattering of waves off classical spinning compact objects. Implications of classical soft theorems in the computation of classical radiation are also discussed. Furthermore, formal aspects of the double copy for massive spinning matter, and its application in a classical two-body context are considered. Finally, the relation between the minimal coupling gravitational Compton amplitude and the scattering of gravitational waves off the Kerr black hole is presented.