Non-Minimal Two-Loop Inflation

TL;DR

This paper explores a non-minimal two-loop inflation model with a scalar field, analyzing its stability and inflationary parameters, and finds it consistent with observational data from Planck, WMAP, and BICEP2.

Contribution

It introduces a detailed two-loop analysis of a non-minimal scalar field inflation model, including stability bounds and parameter exploration, extending prior one-loop studies.

Findings

Two-loop corrections significantly affect the spectral index n_s.

The model remains consistent with observational constraints.

Stability bounds for the de Sitter solution are established.

Abstract

We investigate the chaotic inflationary model using the two-loop effective potential of a self-interacting scalar field theory in curved spacetime. We use the potential which contains a non-minimal scalar curvature coupling and a quartic scalar self-interaction. We analyze the Lyapunov stability of de Sitter solution and show the stability bound. Calculating the inflationary parameters, we systematically explore the spectral index $n_s$ and the tensor-to-scalar ratio $r$, with varying the four parameters, the scalar-curvature coupling $\xi_0$, the scalar quartic coupling $\lambda_0$, the renormalization scale $\mu$ and the e-folding number $N$. It is found that the two-loop correction on $n_s$ is much larger than the leading-log correction, which has previously been studied. We show that the model is consistent with the observation by Planck with WMAP and a recent joint analysis of BICEP2.