Quantum Contributions to Cosmological Correlations II: Can These Corrections Become Large?

TL;DR

This paper investigates quantum corrections to cosmological correlations, demonstrating that such corrections are limited to logarithmic growth and cannot become large, thus maintaining the stability of inflationary predictions.

Contribution

It shows that quantum corrections in cosmology are at most logarithmic in the scale factor, contradicting previous suggestions they could grow large.

Findings

Quantum corrections depend on the entire inflation history.

Corrections are at most logarithmic in the scale factor.

Quantum corrections cannot grow large in perturbation theory.

Abstract

This is a sequel to a previous detailed study of quantum corrections to cosmological correlations. It was found there that except in special cases these corrections depend on the whole history of inflation, not just on the behavior of fields at horizon exit. It is shown here that at least in perturbation theory these corrections can nevertheless not be proportional to positive powers of the Robertson--Walker scale factor, but only at most to powers of its logarithm, and are therefore never large.