Optional adopted classical spinning-orbit model

Adopted model postulate (optional): Under ${\mathrm{A}\mathrm{C}}_{\omega }$ for the referenced KKS orbit, and for fixed primitive parameters $m>0$ (kg) and $s>0$ (angular momentum units), use the coadjoint orbit and KKS symplectic form of Positive classical spin Poincare orbit and stabilizer jump as the phase space of a classical spinning particle. In a selected inertial frame choose the Hamiltonian $H=c{P}^0$ (joules). This premise chooses a mathematical model; it is not inferred from the spinless action, an experiment, or the existence of the orbit alone. It does not assert a quantum spin spectrum, a Wigner unitary representation, a spin supplementary condition, a charged-spin force law, or radiation dynamics.

This item records [A1] as a model choice with the extra Hamiltonian $H=c{P}^0$. No proof of nature's adoption of this model is claimed. The postulate carries no observational or statistical premise.