QED cross sections in strong magnetic fields

TL;DR

This paper develops a new formalism to analyze QED scattering processes in the extreme magnetic fields of magnetar magnetospheres, providing systematic cross section calculations relevant for plasma dynamics.

Contribution

It introduces a novel approach adapted from quark-gluon plasma studies to compute QED cross sections in strong magnetic fields, including finite decay widths of Landau levels.

Findings

First systematic analysis of tree-level QED processes in strong magnetic fields.

Provides open-source Python package with computed cross sections.

Highlights the impact of strong magnetic fields on plasma processes in magnetars.

Abstract

The magnetospheres of magnetars, a class of highly magnetized neutron stars, host magnetic fields exceeding the Schwinger limit, where Quantum Electrodynamics (QED) becomes nonlinear. In such environments, QED scattering processes are strongly modified, which may affect plasma dynamics. In this work, we apply a formalism originally developed for the study of magnetic-field effects in hot quark-gluon plasma to strong-field QED. The method resums interactions between virtual electrons and the external magnetic field, consistently incorporating the finite decay widths of excited Landau levels derived from the fermion self-energy. Using this framework, we perform the first systematic analysis of tree-level QED scattering processes in strong magnetic fields, concentrating on the processes of highest relevance for the plasma dynamics of magnetars. All resulting cross sections are provided in an open-source Python package.