Which theory earned Richard Feynman the 1965 Nobel Prize in Physics?

Quantum electrodynamics earned Richard Feynman the 1965 Nobel Prize in Physics. He shared the prize with Julian Schwinger and Sin-Itiro Tomonaga for fundamental work in quantum electrodynamics, often abbreviated QED.

QED describes how light and matter interact using quantum mechanics and special relativity. It explains phenomena involving photons and electrically charged particles, including electrons. Feynman’s contribution included a practical diagram-based method for calculating interactions, now known as Feynman diagrams.

The 1965 Nobel citation praised their fundamental work in quantum electrodynamics, with deep-ploughing consequences for elementary particles. Feynman did not win the prize alone, and the award recognized a theory developed through contributions from all three laureates.

QED is sometimes confused with quantum chromodynamics, or QCD. QED concerns electromagnetism, while QCD describes the strong interaction between quarks and gluons. QED remains one of the most precisely tested theories in physics.