We begin with quantum electrodynamics (QED), which successfully combines classical electrodynamics, quantum mechanics, and special relativity. QED inherits the gaugetransformation symmetry-called U(1) in group-theoretical language-that classical electromagnetism possesses. QED is also renormalizable; that is, it is well defined mathematically: Infinities that appear at intermediate stages disappear when the theory is expressed in terms of a finite number of measured quantities, such as mass and charge.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)