Description
- Abstract:
- We study scattering amplitudes in N=4 SYM, holographic models of four-dimensional flat-space scattering amplitudes in terms of two-dimensional conformal fields theories dubbed celestial CFTs (CCFT), and the structure of infrared divergences in gauge theories. We begin by enumerating the all-loop singularity structure of seven-point amplitudes in N=4 SYM. We do so by solving the Landau equations for the seven-point Ziggurat graph, and find four new cyclic classes not anticipated by the heptagon symbol alphabet. A highly constraining property of N=4 SYM is it's Yangian symmetry. We classify and enumerate the class of Yangian invariants where the particle number $n$ is related to the helicity violating degree k by n=5k. We then turn to analyzing the properties of CCFTs which are holographically dual to flat-space scattering amplitudes. We analyze the correlation functions and operator product expansions of light-ray operators appearing in the CCFT spectrum. We then turn to loop level analyses of OPEs in CCFT. Lastly, we study infrared divergences in gauge theories. These divergences arise due to the asymptotic states failing to converge appropriately to free particle states. We analyze the asymptotic angular momentum of the classical electromagnetic field in the presence of far-separated charged particles in order to quantify the deviation from free particle states. An interesting feature of the result is that, although the total angular momentum of the EM field and that of the charged particles' is independent of the Cauchy surface on which these quantities are computed, the splitting between field and particle angular momentum is dependent on the details of the Cauchy surface.
- Notes:
- Thesis (Ph. D.)--Brown University, 2023
Citation
Lippstreu, Luke,
"Scattering Amplitudes in N=4 SYM and the Infrared Structure of Gauge Theories"
(2023).
Physics Theses and Dissertations.
Brown Digital Repository. Brown University Library.
https://repository.library.brown.edu/studio/item/bdr:tqeem868/
