Large tensor-to-scalar ratio and running of the scalar spectral index with Instep Inflation

TL;DR

This paper proposes a model of inflation with a flat potential influenced by radiative corrections and high-energy effects, capable of producing a large tensor-to-scalar ratio and negative spectral index running, aligning with potential future observations.

Contribution

It introduces a novel inflationary scenario with a flat tree-level potential modified by radiative and high-energy effects, explaining large tensor-to-scalar ratio and spectral index running.

Findings

The model can produce a tensor-to-scalar ratio around 0.1.

It accounts for a negative running of the scalar spectral index near -0.01.

It sustains sufficient inflation within the slow-roll regime.

Abstract

If a sizeable tensor-to-scalar ratio ~0.1 turns out to be detected and a negative running of the scalar spectral index ~0.01 is significantly required by the data, the vast majority of single field models of inflation will be ruled out. We show that a flat tree-level effective potential, lifted by radiative corrections and by the imprints of a high energy scale (in the form of non-renormalizable operators) can explain those features and produce enough inflation in the slow-roll regime.