For 10 points, identify these values useful in finding total angular momentum in quantum systems, a set of doubly-eponymous coefficients.
Koornwinder found that, under the Askey system, the SU(2) case of these can be expressed as hypergeometric Hahn functions, and they can be used to fully relate the matrix element as the second factor in the Wigner-Eckhart theorem. The painstaking process of completely calculating them for complex operations can be circumvented by instead using similar values named for Racah. These values are closely related to Wigner (*) 3j-symbols, as they yield the integrated product of up to three spherical harmonic functions. These factors are organized in an oft-consulted "table" and used to calculate summations when examining the "coupling" of a certain quantum mechanical quantity. For 10 points, identify these values useful in finding total angular momentum in quantum systems, a set of doubly-eponymous coefficients.
Koornwinder found that, under the Askey system, the SU(2) case of these can be expressed as hypergeometric Hahn functions, and they can be used to fully relate the matrix element as the second factor in the Wigner-Eckhart theorem.
Clebsch-Gordan Coefficients