A modified Starobinsky's model of inflation: Anomaly-induced inflation, SUSY and graceful exit

TL;DR

This paper proposes a modified inflation model based on anomaly-induced effective gravity, incorporating SUSY effects to naturally end inflation and transition to standard cosmology.

Contribution

It introduces a stable-to-unstable inflation transition mechanism driven by quantum effects and SUSY breaking, extending Starobinsky's model.

Findings

Inflation remains stable initially and becomes unstable due to quantum effects.

SUSY breaking provides a natural graceful exit from inflation.

Model aligns with observed cosmological transition requirements.

Abstract

We present a model of inflation based on the anomaly-induced effective action of gravity in the presence of a conformally invariant Hilbert-Einstein term. Our approach is based on the conformal representation of the fields action and on the integration of the corresponding conformal anomaly. In contradistinction to the original Starobinsky's model, inflation can be stable at the beginning and unstable at the end. The instability is caused by a slowing down of inflation due to quantum effects associated to the massive fermion fields. In supersymmetric theories this mechanism can be linked to the breaking of SUSY and suggests a natural way to achieve graceful exit from the inflationary to the FLRW phase.