In pairticle physics, quantum electrodynamics (QED) is the relativistic quantum field theory o electrodynamics. In essence, it describes hou licht an matter interact an is the first theory whaur full agreement atween quantum mechanics an special relativity is achieved. QED mathematically describes aw phenomena involvin electrically charged pairticles interactin bi means o exchynge o photons an represents the quantum coonterpart o classical electromagnetism givin a complete accoont o matter an licht interaction.
In technical terms, QED can be describit as a perturbation theory o the electromagnetic quantum vacuum. Richard Feynman cried it "the jewel o pheesics" for its extremely accurate predictions o quantities lik the anomalous magnetic moment o the electron an the Lamb shift o the energy levels o hydrogen.