Inflation with Planck: a survey of some "exotic" inflationary models

TL;DR

This paper surveys various exotic inflationary models inspired by modifications of gravity, analyzing their compatibility with Planck 2015 data and comparing their predictions to the Starobinsky model.

Contribution

It provides a comprehensive review of alternative inflation models based on modified gravity theories and their observational viability with recent data.

Findings

Some models fit Planck data well

Flat plateau potentials resemble Starobinsky predictions

Modified gravity models offer viable inflationary scenarios

Abstract

We examine some inflationary models based on modifications of gravity in the light of Planck 2015 data, such as the generalised Chaplygin inspired inflation, models based in $N=1$ supergravity and braneworld scenarios. We also show that, conversely, potentials with a very flat plateau yield a primordial spectrum similar to that of the Starobinsky model with no need to modify general relativity.