Probing the primordial power spectra with inflationary priors

TL;DR

This paper uses inflationary priors to constrain primordial power spectra, showing that simple single-field slow-roll inflation models fit current data well, but the scale-invariant spectrum is increasingly disfavored.

Contribution

It introduces a method to incorporate inflationary priors into power spectrum constraints and compares this with standard parameterizations using recent observational data.

Findings

Scale-invariant spectrum is increasingly disfavored.

Current data favor simple single-field slow-roll inflation models.

Data cannot yet distinguish between different slow-roll inflation models.

Abstract

We investigate constraints on power spectra of the primordial curvature and tensor perturbations with priors based on single-field slow-roll inflation models. We stochastically draw the Hubble slow-roll parameters and generate the primordial power spectra using the inflationary flow equations. Using data from recent observations of CMB and several measurements of geometrical distances in the late Universe, Bayesian parameter estimation and model selection are performed for models that have separate priors on the slow-roll parameters. The same analysis is also performed adopting the standard parameterization of the primordial power spectra. We confirmed that the scale-invariant Harrison-Zel'dovich spectrum is disfavored with increased significance from previous studies. While current observations appear to be optimally modeled with some simple models of single-field slow-roll inflation, data is not enough constraining to distinguish these models.