The Observational Status of Cosmic Inflation after Planck

TL;DR

This paper reviews the observational constraints on cosmic inflation from recent Planck and BICEP2/Keck data, discussing how current measurements favor vanilla inflation models and exploring future prospects for detecting primordial gravitational waves.

Contribution

It provides a pedagogical overview linking inflation theory with recent observational data and discusses the implications of current and future measurements for inflation models.

Findings

Current data favor vanilla inflationary models

Plateau-like potentials are preferred within inflation scenarios

Future B-mode polarization measurements could significantly improve understanding

Abstract

The observational status of inflation after the Planck 2013 and 2015 results and the BICEP2/Keck Array and Planck joint analysis is discussed. These pedagogical lecture notes are intended to serve as a technical guide filling the gap between the theoretical articles on inflation and the experimental works on astrophysical and cosmological data. After a short discussion of the central tenets at the basis of inflation (negative self-gravitating pressure) and its experimental verifications, it reviews how the most recent Cosmic Microwave Background (CMB) anisotropy measurements constrain cosmic inflation. The fact that vanilla inflationary models are, so far, preferred by the observations is discussed and the reason why plateau-like potential versions of inflation are favored within this subclass of scenarios is explained. Finally, how well the future measurements, in particular of $B$-Mode CMB polarization or primordial gravity waves, will help to improve our knowledge about inflation is also investigated.