Quantum Electrodynamics

Considered a foundational branch of theoretical physics, Quantum Electrodynamics or QED describes the motion and interaction of electromagnetic forces at the atomic and subatomic level, combining together both quantum mechanics and special relativity. Originally developed by physicists such as Paul Dirac, Richard Feynman and Julian Schwinger in the early 20th century—later enhanced by Shin’ichirō Tomonaga in the mid-20th century—QED comprises a key component of the Standard Model of particle physics, which studies the motions and interactions of electrons, positrons and photons, which in turn predicts the attraction or repulsion of charged particles over time.

Feynman Diagrams

Employing Feynman diagrams to visually describe underlying mathematical equations that predict the exponential multitude of particle reactions over time, electrons are symbolized with an arrow toward the future, positrons are symbolized with an arrow toward the past, massless, non-electrically charged photons are symbolized with a wavy line, while a photon’s effect on force-carrying particles—known as vertices—are represented by a dot. Given the multitude of possible interactive outcomes, physicists rely on the concept of renormalization and perturbative calculations to find approximate and highly accurate predictions regarding the motion and interaction of quantum particles.

Reproducible Results

Experimental verification of QED predictions has proven to be remarkably successful in the ongoing study of theoretical physics, allowing physicists to understand quantum interactions to an extraordinary level—oftentimes with mathematical agreements into parts per trillion—which in turn reflects a growing understanding of the universe we live in. The study of Quantum Electrodynamics has played a crucial role in advancing our understanding of particle physics, further reconciling quantum mechanics and special relativity, at the same time adding to the development of a broader Standard Model, making Quantum Electrodynamics, the most accurate theory of nature, ever devised by man.