# Asymptotic $U(1)$ charges at spatial infinity

## TL;DR

This paper unifies the description of large gauge symmetries and their charges at spatial infinity and asymptotic times in Minkowski spacetime, showing their conservation and connection to soft photon theorems.

## Contribution

It provides a unified framework for large gauge symmetries at spatial infinity and asymptotic times using harmonic gauge, linking charges and soft theorems.

## Key findings

- Charges are conserved at spatial infinity.
- Charges interpolate between past and future asymptotic regimes.
- Supports the connection with Weinberg's soft photon theorem.

## Abstract

Large gauge symmetries in Minkowski spacetime are often studied in two distinct regimes: either at asymptotic (past or future) times or at spatial infinity. By working in harmonic gauge, we provide a unified description of large gauge symmetries (and their associated charges) that applies to both regimes. At spatial infinity the charges are conserved and interpolate between those defined at the asymptotic past and future. This explains the equality of asymptotic past and future charges, as recently proposed in connection with Weinberg's soft photon theorem.