How the spin-orbit interaction appears with the same order of a non-commutative change of framework for relativistic fermions

In this research, in a difficult but absolutely precise way of calculation, we show how a very tiny amount of a non-commutative change of quantum space would appear almost as big as a normal physical interaction, namely the Rashba spin-orbit interaction, for relativistic fermions. Hence, in order to show that, we firstly solve a relativistic equation of motion of a Dirac particle, influenced by a typical harmonic energy-dependent interaction for commutative and non-commutative frameworks via the Nikiforov–Uvarov exact approach. Then to study perturbation effects of a spin-orbit interaction, we apply it for both mentioned frameworks, obtaining their energy polynomial relations and discriminant formula to precisely extract all physical-admissible roots of their quartic equations. In this step, we analyze the behaviors of their quartic eigenvalue polynomials in four sections and accurately compare them one by one. Finally, we distinctly show that the magnitude of the physical spin-orbit perturbation appears, almost of the same order of imposing a non-commutative geometry change of framework, as an outstanding result.