K-nonizing

Abstract

We unveil the dynamical equivalence of field theories with non-canonical kinetic terms and canonical theories with a volume element invariant under transverse diffeomorphisms. The proof of the equivalence also reveals a subtle connection between the standard Legendre transformation and the so-called Clairaut equation. Explicit examples of canonizable theories include classes of k-essence, non-linear electrodynamics, or f (R) theories. The equivalence can also be extended to the class of mimetic theories.