  This paper presents an evaluation of the wave function coefficients for
conformally coupled scalars at both one and two-loop levels at leading order in
the coupling constant, in momentum space. We take cues from time-dependent
interactions in flat spacetime and under suitable approximations, these can
also be used to study the wave function coefficients for general cosmologies.
We make use of recursion relations developed in arxiv:\{1709.02813\} to
regularize certain bulk-point integrals and express the wave function
coefficients in a form that simplifies the loop integrals. We utilize
hard-cutoff regularization to regularize the loop integrals and further provide
a discussion on their renormalization. Our results can also be analytically
continued to obtain answers for transition amplitudes in AdS.
