Asymptotic States and S-matrix

This lecture covers the concept of asymptotic states and S-matrix in quantum field theory, focusing on the evolution of wave packets and the scattering states. The instructor explains the importance of discrete symmetries and the role of S-matrix in potential scattering. The lecture delves into the formalism of S-matrix elements and their relation to the Lippmann-Schwinger equation, emphasizing the unitarity of the S-matrix. Additionally, the lecture discusses the measurement in quantum mechanics, spin preparation, and the possibilities of spin states. The content also includes the application of the S-matrix in understanding the interaction amplitudes and the unitarity of the theory.