Understand
Gauge theories possess nonlocal features that, in the presence of boundaries, inevitably lead to subtleties.
- We employ geometric methods rooted in the functional geometry of the phase space of Yang-Mills theories to: (1) characterize a basis for quasilocal degrees of freedom (dof) that is manifestly gauge-covariant also at the boundary; (2) tame the non-additivity of the regional symplectic forms upon the gluing of regions; and to (3) discuss gauge and global charges in both Abelian and non-Abelian theories from a geometric perspective.
- Naturally, our analysis leads to splitting the Yang-Mills dof into Coulombic and radiative.
- Coulombic dof enter the Gauss constraint and are dependent on extra boundary data (the electric flux); radiative dof are unconstrained and independent.