Remarks on the constraint structure and the quantization of the Rarita-Schwinger field

The role of the spin-1/2 components in the constraint structure of the Rarita-Schwinger field with minimal electromagnetic coupling is understood in terms of a simple mechanical analog. While one of the spin-1/2 components plays the role of a Lagrangian multiplier, the other is directly responsible for the difficulty of quantization observed by Johnson and Sudarshan. We surmise that this is the common origin of most of the difficulties discussed so far in the literature. In as much as our results are derived from a mechanical model, our analysis applies to a considerably large class of interactions and shows how the interpretation of Poisson brackets as anticommutators of field operators (Jordan-Wigner procedure) is not always automatic as it is commonly accepted