Two-field axion inflation and the swampland constraint in the flux-scaling scenario

TL;DR

This paper explores a string theory-based two-axion inflation model within flux compactifications, demonstrating compatibility with observational data and swampland constraints through flux tuning.

Contribution

It introduces a flux-scaling scenario with two-axion inflation that satisfies observational bounds and swampland criteria, advancing string cosmology models.

Findings

Cosmological parameters remain within observed bounds with flux tuning.

The model satisfies the swampland criterion for multi-field inflation.

Inflationary trajectories deviate from geodesics in controlled flux regimes.

Abstract

Based on the flux-scaling scenario we study a model consisting on Type IIB string theory compactified on a Calabi-Yau manifold with a frozen complex structure in the presence of generic fluxes. The model contains (meta)stable Minkowski and de Sitter vacua as well as inflationary directions driven by two independent linear combination of axions. Due to a numerical control by fluxes, we show that cosmological parameters as the spectral index, tensor-to-scalar ratio and non-Gaussianities can be kept within observed bounds while preserving the desired hierarchies on physical scales. Moreover we compute the deviation of the inflationary trajectories from geodesics on field space in terms of the fluxes showing that for some regions, they fulfill the recent proposed swampland criterion for multi-field scenarios.