Conservation Laws from Asymptotic Symmetry and Subleading Charges in QED

TL;DR

This paper explores the connection between asymptotic symmetries, memory effects, and soft theorems in massive QED, clarifying charge conservation and deriving new expressions for subleading charges.

Contribution

It provides a detailed analysis of memory effects and asymptotic charges in massive QED, including the derivation of subleading charges and their conservation properties.

Findings

Memory effects correspond to charge conservation of large gauge transformations.

Sub-subleading charges are not conserved without spacelike infinity contributions.

Explicit expressions for charges related to subleading soft photons in massive scalar QED.

Abstract

We present several results on memory effects, asymptotic symmetry and soft theorems in massive QED. We first clarify in what sense the memory effects are interpreted as the charge conservation of the large gauge transformations, and derive the leading and subleading memory effects in classical electromagnetism. We also show that the sub-subleading charges are not conserved without including contributions from the spacelike infinity. Next, we study QED in the BRST formalism and show that parts of large gauge transformations are physical symmetries by justifying that they are not gauge redundancies. Finally, we obtain the expression of charges associated with the subleading soft photon theorem in massive scalar QED.