2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/194854This paper extends the calculation of quantum corrections to the cosmological correlation $<ζζ>$, which has been done by Weinberg for a loop of minimally coupled scalars, to other types of matter loops and a general and realistic potential. It is shown here that departures from scale invariance are never large even when Dirac, vector, and conformal scalar fields are present \emph{during} inflation. No fine tuning is needed, in the sense that effective masses or coupling constants can have arbitrary values. Even when the mass is as large as $M_{Pl}$, the one-loop result is still naturally smaller than the classical one. Thus, the results show that the existence of these fields \emph{during} inflation may not be ruled out and is consistent with natural reheating.52 pages,v2:changed local report-no,v3 added references, corrected typos, clarified contents, accepted for publication in Physical Review DHigh Energy Physics - TheoryAstrophysicstext