Renormalization and Beta Function

This lecture covers the process of renormalization in quantum field theory, focusing on the beta function and its implications. The instructor explains how to adjust the theory by adding counterterms at different loop levels, leading to normalizable theories. The lecture delves into the relationship between bare parameters, bare fields, and corrections, emphasizing the importance of ensuring observables do not depend on the renormalization scale. By examining the beta function, the instructor demonstrates how the theory behaves in the infrared and ultraviolet limits, highlighting the significance of sign differences in determining the theory's behavior. The lecture concludes with a detailed analysis of perturbation theory and the systematic calculation of loop corrections.