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 tamén resolveu o problema de poñer a ecuación Schwinger-Tomonaga na representación de Schrödinger e deu expresións explícitas para o campo meson escalar (pión spin cero ou meson pseudoscalar), o campo meson vector (mesón ρ spin un), e o campo electromagnético (bosón sen masa de spin un, fotón).