Positronium in relativistic quantum mechanics

Abstract

The problem of bound states of a charged particle and its antiparticle is formulated in the framework of the relativistic quantum mechanics of a single scalar particle interacting with the electromagnetic field. The Coulomb interaction between the particle and the antiparticle gives rise to the bound states, and the coupling of the wave function to the radiation field is responsible for the decay of the pair into electromagnetic energy. The contribution of a pion-pion interaction is discussed briefly. The theory is extended to the spin- 1 2 electron.