String Inflation After Planck 2013

TL;DR

This paper reviews how recent Planck data impacts string inflation models, discussing their predictions, complexity, and future prospects for detecting primordial gravitational waves.

Contribution

It provides a summary of the effects of Planck measurements on string inflation models and assesses their viability with current and future observational constraints.

Findings

Pre-Planck predictions align well with observations.

String inflation models face challenges from non-Gaussianity and dark radiation constraints.

Future sensitivity improvements may clarify the role of these models.

Abstract

We briefly summarize the impact of the recent Planck measurements for string inflationary models, and outline what might be expected to be learned in the near future from the expected improvement in sensitivity to the primordial tensor-to-scalar ratio. We comment on whether these models provide sufficient added value to compensate for their complexity, and ask how they fare in the face of the new constraints on non-gaussianity and dark radiation. We argue that as a group the predictions made before Planck agree well with what has been seen, and draw conclusions from this about what is likely to mean as sensitivity to primordial gravitational waves improves.