is the relativistic quantum field theory that describes how light and matter interact. It specifically focuses on the interactions between electrically charged particles (like electrons and positrons) and the electromagnetic field (represented by photons). The "Jewel of Physics"
According to Feynman’s formulation, the entire universe of QED can be boiled down to three simple actions: A photon goes from one place and time to another. An electron goes from one place and time to another. Quantum Electrodynamics
An electron emits or absorbs a photon at a specific place and time. Why It Matters is the relativistic quantum field theory that describes
In QED, the electromagnetic force isn't a "static" field, but rather an exchange of photons . When two electrons repel each other, they are effectively "tossing" photons back and forth. An electron goes from one place and time to another
Developed by Richard Feynman, these are visual tools used to calculate the probability of particle interactions. Lines represent particles, and "vertices" represent where they meet and exchange energy. Licensed by Google Three Basic Actions
QED is often called the most successful theory in the history of science because its predictions match experimental results with incredible precision—comparable to measuring the distance from New York to Los Angeles within the width of a human hair. Core Principles
Beyond being a mathematical masterpiece, QED provided the blueprint for the of particle physics. It showed scientists how to combine quantum mechanics with special relativity and successfully handle "renormalization"—a mathematical technique to remove the "infinities" that previously broke earlier theories.