On the renormalization of ultraviolet divergences in the inflationary angular power spectrum

Abstract

We revise the role that ultraviolet divergences of quantum fields play in slow-roll inflation, and discuss the renormalization of cosmological observables from a space-time perspective, namely the angular power spectrum. We first derive an explicit expression for the multipole coefficients $C_{\ell }$ in the Sachs-Wolfe regime in terms of the two-point function of primordial perturbations. We then analyze the ultraviolet behavior, and point out that the standard result in the literature is equivalent to a renormalization of $C_{\ell }$ at zero ``adiabatic'' order. We further argue that renormalization at second ``adiabatic'' order may be more appropriate from the viewpoint of standard quantum field theory. This may change significantly the predictions for $C_{\ell }$, while maintaining scale invariance.

Proceedings of the "Spanish Relativity Meeting (ERE 2014): almost 100 years after Einstein's revolution"

References in corpus (3)

• The Creation of Particles in an Expanding Universe
• Equivalence of Adiabatic and DeWitt-Schwinger renormalization schemes
• Study of the Spectrum of Inflaton Perturbations