Question

What do we call the theory of electromagnetism on the particle scale?

Answer 1

quantum electrodynamics

33.2 The Four Basic Forces  The four basic forces and their carrier particles are summarized in the Table 33.1.  Feynman diagrams are graphs of time versus position and are highly useful pictorial representations of particle processes.  The theory of electromagnetism on the particle scale is called quantum electrodynamics  QED .