 Clebsch–Gordan coefficients

Clebsch-Gordan coefficients are the change-of-basis coefficients between an uncoupled tensor-product basis and a basis adapted to the irreducible decomposition of the tensor product.

The Clebsch–Gordan coefficients are numerical factors that arise in the study of angular momentum in quantum mechanics and in the theory of representations of groups, specifically the group \( SU(2) \) associated with rotations. They describe how to combine two angular momentum states into a total angular momentum state.