Introducing the strong nuclear interaction and many-body physics in undergraduate quantum mechanics

The standard treatment of spin in undergraduate quantum mechanics provides all the essential ingredients for introducing a number of exciting and contemporary topics which are of great interest to the condensed-matter and high-energy physics community but which are also rarely addressed in a meaningful way at the undergraduate level. Specifically, the color charge of quantum chromodynamics possesses a structure which is quite similar to the electron's spin degree of freedom. By considering a system of three color charges at fixed positions with Heisenberg-like interactions, one is able to construct a toy model of a baryon with tunable interaction strength in which the color charge components exhibit dynamics similar to those of interacting spin components. The system of three particles leads naturally to an exploration of three-body interactions, which are highly relevant to quantum chromodynamics. Moreover, the overall approach to investigating the system's nontrivial dynamics provides a digestible introduction to the technique of exact diagonalization in a novel, few-body quantum system. VPython is used to visualize the emergent dynamics, providing an interesting demonstration which is appropriate for a course on modern physics.