Quantum stability of Proca-Nuevo

Understand

The construction of general derivative self-interactions for a massive Proca field relies on the well-known condition for constrained systems of having a degenerate Hessian.

• The nature of the existing constraints algebra will distinguish among different classes of interactions.
• Proca-Nuevo interactions enjoy a non-trivial constraint by mixing terms of various order whereas Generalized Proca interactions satisfy the degeneracy condition order by order for each individual Lagrangians.
• In both cases the vector field propagates at most three degrees of freedom.