Methodologies

There are two equivalent ways that one can think about using isospin. One is the one that is conventionally used in nuclear physics, where one thinks in terms of states, and combines states with tabulated Clebsch-Gordan coefficients (CG's) (which can be found in [3] and other texts). The other approach is to think in terms of the annihilation and creation operators, and generate the CG's via the Wigner-Eckart theorem. Let us examine both methods with a couple of simple examples.

Nice discussions of group theory can be found in references [5] and [6].