Quantum Field Theory: Gauge Symmetries

This lecture covers the concept of gauge symmetries in quantum field theory, focusing on the invariance under different transformations. It discusses the Lie parameters, Cartan forms, and the Feddeev-Popov ghost fields. The lecture also explores the role of invariant measures and the importance of ghost propagators in the context of Lorentz gauge. The instructor emphasizes the independence of observables and the significance of Fourier transformations in the theory. Additionally, the lecture delves into the practical aspects of implementing gauge symmetries in calculations.