## Abstract

We discuss the emergence of a new symmetry generator in a Hamiltonian realisation of four-dimensional gauge theories in the flat space foliated by retarded (advanced) time. It generates an asymptotic symmetry that acts on the asymptotic fields in a way different from the usual large gauge transformations. The improved canonical generators, corresponding to gauge and asymptotic symmetries, form a classical Kac-Moody charge algebra with a non-trivial central extension. In particular, we describe the case of electromagnetism, where the charge algebra is the U(1) current algebra with a level proportional to the coupling constant of the theory, κ = 4π ^{2}/e ^{2}. We construct bilinear generators yielding Virasoro algebras on the null boundary. We also provide a non-Abelian generalization of the previous symmetries by analysing the evolution of Yang-Mills theory in Bondi coordinates.

Original language | English |
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Article number | 165 |

Journal | Journal of High Energy Physics |

Volume | 2023 |

Issue number | 6 |

DOIs | |

State | Published - 2023 |

Externally published | Yes |

### Bibliographical note

Publisher Copyright:© 2023, The Author(s).

## ASJC Scopus subject areas

- Nuclear and High Energy Physics