Abelian Gauge Theory establishes a framework for local U(1) symmetry invariance by introducing a gauge connection field (the photon), necessitating the replacement of partial derivatives with covariant derivatives to maintain form-independence under spacetime-dependent phase rotations. The resulting dynamics are governed by an action derived purely from symmetry principles, where gauge invariant kinetic terms utilize the Abelian field strength tensor and specific parity-preserving constraints exclude total derivative theta-terms, thereby defining Quantum Electrodynamics without additional ad-hoc assumptions.
Abelian Gauge Theory establishes a framework for local U(1) symmetry invariance by introducing a gauge connection field (the photon), necessitating the replacement of partial derivatives with covaria…