2013/08/31 by Andrew Strominger · 3 citations
Mathematics · Physics and Astronomy · #gr-qc #hep-th #math-ph #math.MP
paper · pdf · doi:10.1007/jhep07(2014)151
19 pages, 1 figure. Revised version contains minor edits and additional references
arxiv created 2013/12/23 · arxiv updated 2015/06/16
Asymptotic symmetries at future null infinity (I+) of Minkowski space for electrodynamics with massless charged fields, as well as non-Abelian gauge theories with gauge group G, are considered at the semiclassical level. The possibility of charge/color flux through I+ suggests the symmetry group is infinite-dimensional. It is conjectured that the symmetries include a G Kac-Moody symmetry whose generators are "large" gauge transformations which approach locally holomorphic functions on the conformal two-sphere at I+ and are invariant under null translations. The Kac-Moody currents are constructed from the gauge field at the future boundary of I+. The current Ward identities include Weinberg's soft photon theorem and its colored extension.