Curvature radiation from a quantum-electrodynamics point of view

Curvature radiation, or radiation of a charged particle along a curved magnetic field line, is an important phenomenon for generating gamma photons in pulsar and magnetar magnetospheres. So far the theoretical treatment was based on the classical treatment of synchrotron radiation. However, in the context of neutron-star magnetospheres magnetic fields can be so intense that the quantified regime is quickly reached and the classical theory may fail or be incomplete. Here we develop the main steps to build a theory of curvature radiation fully based on quantum-electrodynamics first principles and applicable in the ultra-relativistic, high-magnetic-field regime typical of neutron-star magnetospheres. We show that classical expressions can be obtained from first principles but also that new transitions arise that can be interpreted as spin flips and may not be negligible as the magnetic field rises.