Dante's Waterfall

TL;DR

The paper introduces a hybrid axion-monodromy inflation model inspired by Dante's Inferno, combining features of single-field and hybrid inflation to match cosmic microwave background observations.

Contribution

It proposes a novel two-field inflation model with a spiral trajectory and a hybrid termination mechanism, extending axion-monodromy frameworks.

Findings

Reproduces observed CMB features

Evades the Lyth bound via shift symmetry

Provides parameter choices consistent with BICEP2 and Planck data

Abstract

We describe a hybrid axion-monodromy inflation model motivated by the Dante's Inferno scenario. In Dante's Inferno, a two-field potential features a stable trench along which a linear combination of the two fields slowly rolls, rendering the dynamics essentially identical to that of single-field chaotic inflation. A shift symmetry allows for the Lyth bound to be effectively evaded as in other axion-monodromy models. In our proposal, the potential is concave downward near the origin and the inflaton trajectory is a gradual downward spiral, ending at a point where the trench becomes unstable. There, the fields begin falling rapidly towards the minimum of the potential and inflation terminates as in a hybrid model. We find parameter choices that reproduce observed features of the cosmic microwave background, and discuss our model in light of recent results from the BICEP2 and Planck experiments.