Simultaneous geometrization of classical and quantum mechanics of particles with spin

It is shown that the classical equations of motion for particles having internal degrees of freedom, i.e., spin (Nyborg equations) allow for a geometrization on a special manifold V₄. It is also shown that the equation for a harmonic function on V₄ (with an additional vector bundle on which a spinor connection is defined) is a squared Dirac equation.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 10, pp. 76–80, October, 1990.