Phenomenological investigation of a quantum gravity extension of inflation with the Starobinsky potential

TL;DR

This paper explores how quantum gravity effects influence the early universe's inflationary phase with the Starobinsky potential, revealing observable signatures and unique deviations in tensor modes that could impact cosmological observations.

Contribution

It introduces a loop quantum cosmology framework to study pre-inflationary dynamics with the Starobinsky potential, highlighting potential observable quantum gravity signatures.

Findings

Inflation compatible with observations occurs for most initial conditions.

Quantum gravity signatures can be potentially observable in some initial data.

Deviations in tensor modes are unique to the Starobinsky potential and relevant for non-Gaussian features.

Abstract

We investigate the pre-inflationary dynamics of inflation with the Starobinsky potential, favored by recent data from the Planck mission, using techniques developed to study cosmological perturbations on quantum spacetimes in the framework of loop quantum cosmology. We find that for a large part of the initial data, inflation compatible with observations occurs. There exists a subset of this initial data that leads to quantum gravity signatures that are potentially observable. Interestingly, despite the different inflationary dynamics, these quantum gravity corrections to the powerspectra are similar to those obtained for inflation with a quadratic potential, including suppression of power at large scales. Furthermore, for super horizon modes the tensor modes show deviations from the standard inflationary paradigm that are unique to the Starobinsky potential and could be important for non-Gaussian modulation and tensor fossils.