In this section, we review how to use the generators of the su(N ) Lie algebra to represent a Hamiltonian operator. The su(N ) Lie algebra and its corresponding Lie group are widely used in fundamental physics, particularly in the Standard Model of particle physics. For example, the su(2) Lie algebra is used to describe the spin- 2 system. The generators of su(2) are the spin operators Ŝj = 2 σ j with the two-dimensional represented Pauli matrices defined as follows