Hamiltonian Gauge Theory With Corners II: memory as superselection in null YM theory

          @misc{ pirsa_PIRSA:22100027,
            doi = {10.48660/22100027},
            url = {https://pirsa.org/22100027},
            author = {Riello, Aldo},
            keywords = {Quantum Gravity},
            language = {en},
            title = {Hamiltonian Gauge Theory With Corners II: memory as superselection in null YM theory},
            publisher = {Perimeter Institute},
            year = {2022},
            month = {oct},
            note = {PIRSA:22100027 see, \url{https://pirsa.org}}
          }
          

Abstract

On Tuesday, M. Schiavina laid out the theoretical framework for the symplectic reduction of gauge theories in the presence of corners. In this talk I will apply this theoretical framework to Yang-Mills theory on a null boundary and show how a pair of soft charges controls the residual (corner) gauge symmetry after the first-stage symplectic reduction, and therefore the superselection structure of the theory after the second-stage symplectic reduction. I will also discuss the subtleties of the gauge A_u = 0, the interpretation of electromagnetic memory as superselection, and how the nonlinear structure of the non-Abelian theory complicates this picture.