Quantum electrodynamics

Quantum electrodynamics (QED) is a quantum field theory of electromagnetism. QED describes all phenomena involving electrically charged particles interacting by means of the electromagnetic force and has been called "the jewel of physics" for its extremely accurate predictions of quantities like the anomalous magnetic moment of the muon, and the Lamb shift of the energy levels of hydrogen.

Physical interpretation of QED

Physically, QED describes charged particles (and their antiparticles) interacting with each other by the exchange of photons. The magnitude of these interactions can be computed using perturbation theory; these rather complex formulas have a remarkable pictorial representation as Feynman diagrams. QED was historically the theory to which Feynman diagrams were first applied. These diagrams had been invented from Lagrangian mechanics.

Related Topics:
Antiparticle - Photon - Perturbation theory - Feynman diagram - Lagrangian mechanics

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