# Gauss' Law and String-Localized Quantum Field Theory

## TL;DR

This paper presents a novel approach to quantum electrodynamics (QED) that enforces Gauss' Law without relying on indefinite metrics, thereby maintaining causality and addressing the algebraic and superselection structures of charged particles.

## Contribution

The authors develop a new framework for QED that satisfies Gauss' Law and causality without using indefinite metrics or ghosts, improving the understanding of charged particles and photon clouds.

## Key findings

- Charged particles are accompanied by non-Fock photon clouds.
- The new approach secures causality and Gauss' Law simultaneously.
- It aligns with recent theoretical results by Buchholz et al.

## Abstract

The quantum Gauss Law as an interacting field equation is a prominent feature of QED with eminent impact on its algebraic and superselection structure. It forces charged particles to be accompanied by "photon clouds" that cannot be realized in the Fock space, and prevents them from having a sharp mass. Because it entails the possibility of "measurement of charges at a distance", it is well-known to be in conflict with locality of charged fields in a Hilbert space. We show how a new approach to QED advocated by the authors, that avoids indefinite metric and ghosts, can secure causality and achieve Gauss' Law along with all its nontrivial consequences. We explain why this is not at variance with recent results in a paper by Buchholz et al.