Primordial Black Holes, Eternal Inflation, and the Inflationary Parameter Space after WMAP5

TL;DR

This paper analyzes constraints on single-field inflation models using WMAP5 data, focusing on the inflationary parameter space, primordial black hole production, and eternal inflation, employing the Slow Roll Reconstruction method.

Contribution

It introduces a refined analysis of inflationary parameters considering observational data and priors on inflation duration, highlighting constraints on models avoiding black hole overproduction and eternal inflation.

Findings

Large scale dependence in scalar spectrum slope compatible with viable models.

Constraints exclude parameters leading to primordial black hole overproduction.

Inclusion of inflation duration priors significantly restricts inflationary parameter space.

Abstract

We consider constraints on inflation driven by a single, minimally coupled scalar field in the light of the WMAP5 dataset, as well as ACBAR and the SuperNova Legacy Survey. We use the Slow Roll Reconstruction algorithm to derive optimal constraints on the inflationary parameter space. The scale dependence in the slope of the scalar spectrum permitted by WMAP5 is large enough to lead to viable models where the small scale perturbations have a substantial amplitude when extrapolated to the end of inflation. We find that excluding parameter values which would cause the overproduction of primordial black holes or even the onset of eternal inflation leads to potentially significant constraints on the slow roll parameters. Finally, we present a more sophisticated approach to including priors based on the total duration of inflation, and discuss the resulting restrictions on the inflationary parameter space.