The achievement depended on complementary ways to organize the same physics. In his Nobel lecture, delivered in 1966 for the 1965 prize, Sin-Itiro Tomonaga described covariant contact transformations and replacing the unobservable bare mass and electric charge by experimental values. He also credited Julian Seymour Schwinger's magnetic-moment work and Richard Feynman's methods for extending the approximation.[ref]
Development of Quantum Electrodynamics: Personal recollections by Sin-Itiro Tomonaga. Development of Quantum Electrodynamics, May 6, 1966; concluding discussion of renormalization and complementary calculations
Richard Feynman's 1965 lecture traced his spacetime and path integral viewpoint and the Feynman diagrams that made perturbation theory easier to organize. He emphasized that the path integral viewpoint helped him find expressions without being essential to every calculation. These accounts support shared credit for workable renormalized QED, not attribution of the whole theory to a single person.[ref]
The Development of the Space-Time View of Quantum Electrodynamics by Richard Feynman. The Development of the Space-Time View of Quantum Electrodynamics, December 11, 1965; paragraphs on manifest covariance, diagrams and the final assessment of path integrals
Nobel Prize in Physics in 1965 2026-10-18
Awarded in equal shares to Sin-Itiro Tomonaga, Julian Seymour Schwinger and Richard Feynman for fundamental work in quantum electrodynamics, with consequences for elementary particles.[ref]
The Nobel Prize in Physics 1965 by Nobel Prize Outreach. Individual official award summary: all three laureates, one-third shares, and common quantum-electrodynamics motivation.