Gauge? Who is he?

No, gauge does not indicate the name of a famous theorist. The word is to be considered a historical misnomer for phase. Gauge theories are a special class of relativistic quantum field theories based on the idea that some transformations (e.g. phase transformations) leave unchanged the Lagrangian of the system (symmetries).  Gauge invariance (or gauge symmetry) is the property … Continue reading Gauge? Who is he?