  In the recent paper [3] it was shown that the consistency of the quantum
theory of a sterile scalar coupled to massive fermions requires the inclusion
of odd-power terms in the potential of scalar self-interaction. One of the most
important examples of a sterile scalar is the inflaton, that is typically a
real scalar field which does not belong to representations of particle physics
gauge groups, such as $SU(2)$. Here we explore the effects of the odd-power
terms in the inflaton potential on main observables, such as the scalar
spectral index $n_s$ and the tensor-to-scalar ratio $r$, in the case of a
strong, non-minimal coupling of the inflaton to gravity.
