gauge invariance


gauge invariance

[′gāj in′ver·ē·əns] (electromagnetism) The invariance of electric and magnetic fields and electrodynamic interactions under gauge transformations. (physics) The invariance of any field theory under gauge transformations. (quantum mechanics) An invariance of a Lagrangian based on an internal gauge group, such as U(1) for electromagnetism or U(1) × SU(2) for the Weinberg-Salam unified model of weak and electromagnetic interactions.