PhD Defense: Chenliang Su

Speaker: Chenliang Su

Title: Extended Objects Physics: Defects in Quantum Field Theory and World volume Dynamics of Black Holes

Abstract: The first part studies extended operators, or defects, in supersymmetric quantum field theories, which can break supersymmetries in a controlled manner and probe the validity of a variety of non-perturbative techniques, e.g. integrability. We first explore Gukov-Witten surface defects in N=4 super-Yang-Mills theory and identify regions of parameter space where integrability survives. Then, we investigate domain wall defects in ABJM theory and determine the spectrum of quantum fluctuations in presence of defects. We find that the resulting spectrum reflects the remaining supersymmetries as expected.

The second part addresses the challenge of describing spinning black holes by an extended body model. The point-particle approximation, although effective at low spin, becomes inadequate for rapidly rotating black holes where the finite-size effects and the response of black hole source prominently come into play. We then develop a higher-dimensional hypersurface action, which reproduces the classical three-point amplitudes of Kerr black hole to all spin orders and therefore source a stationary Kerr metric. We further compute the two-graviton Compton amplitude and find agreement with the Kerr result up to the spin-quadratic order.

Supervisor: Charlotte Kristjansen