Who introduced a map that was used by a Nobel Prize winning physicist to work out the theory of quantum angular momentum?
Jordan map In theoretical physics, the Jordan map, often also called the Jordan–Schwinger map is a map from matrices M to bilinear expressions of quantum oscillators which expedites computation of representations of Lie Algebras occurring in physics. It was introduced by Pascual Jordan in 1935 and was utilized by Julian Schwinger in 1952 to re-work out the theory of quantum angular momentum efficiently, given that map’s ease of organizing the (symmetric) representations of su(2) in Fock space.
Mandelstam variables In theoretical physics, the Mandelstam variables are numerical quantities that encode the energy, momentum, and angles of particles in a scattering process in a Lorentz-invariant fashion. They are used for scattering processes of two particles to two particles. The Mandelstam variables were first introduced by physicist Stanley Mandelstam in 1958.