Relativistic rotator of the Dirac equation

From a canonical realization of the Galilei group algebra in the phase space of a moving rotator and the relativistic world-line condition, the canonical realizations of the Poincare group algebra in the phase space of a rotator are determined. A system associated with such an algebra is called a relativistic rotator. Certain among these realizations of the Poincare algebras are o special importance, because the corresponding quantum relativistic rotators satisfy the equation whose matrix representation is identical with the Dirac free-particle equation. This system is called a relativistic rotator of the Dirac equation