Lecture
This lecture introduces the symmetries of empty space, including Parity (P) and Time reversal (T), and explains how they affect scalar and vector fields, electromagnetic fields, and fermions. It covers the concepts of helicity, chirality, and their relation, as well as the charge conjugation (C) symmetry. The lecture explores the symmetries in Quantum Electrodynamics (QED) and provides examples of beta decay and kaon decays to illustrate the violation of parity and CP symmetry. It concludes with a discussion on the generation of non-zero charge from a symmetric initial state.