Dirac had also solved the problem of putting the Schwinger–Tomonaga equation into the Schrödinger representation and given explicit expressions for the scalar meson field (spin zero pion or pseudoscalar meson), the vector meson field (spin one rho meson), and the electromagnetic field (spin one massless boson, photon).
Dirac løste også problemet med at indsætte Tomonaga–Schwinger ligningen i Schrödingers representation og give en eksplicit udtryk for det skalære meson-felt (nul spin pion or pseudoscalar meson), vektor meson-feltet (spin et Rho meson) - og det elektromagnetiske felt (spin et masseløs boson, foton).