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

### APA

Riello, A. (2022). Hamiltonian Gauge Theory With Corners II: memory as superselection in null YM theory. Perimeter Institute. https://pirsa.org/22100027

### MLA

Riello, Aldo. Hamiltonian Gauge Theory With Corners II: memory as superselection in null YM theory. Perimeter Institute, Oct. 07, 2022, https://pirsa.org/22100027

### BibTex

@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}} }

Perimeter Institute for Theoretical Physics

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Talk Type

**Subject**

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.