“Dynamical” interactions and gauge invariance

In order to avoid known, long-standing problems with higher-spin interactions, the electromagnetic field is introduced “dynamically” by using a nonsingular, Lorentz-type transformation, acting as adjoint representation on the Poincaré algebra of the free theory. In doing so, Lorentz transformation and local gauge transformation are placed on the same foundations, leading to the phase transition as a consequence of the gauge transformation. The procedure is exemplified in the case of plane waves for the Dirac-type equation and the Rarita-Schwinger equation.