4 NS, QPf Second Semester. Building upon the foundations of quantum mechanics, we will investigate how these concepts are used in modern physics. Depending on student and professor interest, we will investigate some of the following topics: time-dependent perturbation theory, variational methods, scattering theory, relativistic quantum field theories, quantum electrodynamics, Feynman diagrams, computational methods in quantum mechanics, quantum computers, and experimental tests and implications of quantum mechanics.