High Energy Physics Seminar
Speaker: Callum Jones, University of Michigan
Title: Universality and Emergence from On-Shell Recursion
Refreshments available at 1:30 pm.
Date: Tue, 23 Jan 2018, 1:45 pm – 2:45 pm
Location: 1400 BPS Bldg.
In both phenomenological and formal applications, the methods of effective field theory have been successfully used to describe the long-distance physics of local quantum field theories. The structure of the effective action describing only massless degrees of freedom is usually presented as an indispensable tool for understanding the structure of the vacuum and patterns of spontaneous symmetry breaking. The explicit construction of the effective action is beset with difficulties and in all but the simplest cases produces a result in which only a subset of the physical symmetries are manifest. In this talk I will describe newly developed on-shell methods which allow the direct recursive construction of the S-matrix at leading order. In particular I will describe how the physical content of the S-matrix for the scattering of Goldstone modes is encoded in and completely determined by universal low-energy theorems which follow from a pattern of spontaneous symmetry breaking. I will explain how the on-shell recursive construction gives new insight into the emergence of electric-magnetic duality symmetries at long-distances and the physics of the partial spontaneous breaking of supersymmetry.