Axion-Scalar Dynamics: from the Distance Conjecture to Cosmic Acceleration

TL;DR

This paper explores axion-scalar cosmology in string theory compactifications, testing the Distance Conjecture in dynamical settings and discovering solutions with asymptotic accelerated expansion.

Contribution

It extends the analysis of the Distance Conjecture to finite distance limits and uncovers new solutions exhibiting asymptotic acceleration.

Findings

All late-time solutions at infinite distance verify the conjecture.

Finite distance limits do not necessarily have finite trajectory length.

New solutions show asymptotic accelerated expansion near moduli space boundaries.

Abstract

We discuss the cosmology of axion-scalar systems in asymptotic limits of type IIB/F-theory flux compactifications. These results allow us to test a putative extension of the Distance Conjecture in a dynamical setting, which posits that towers of states should become exponentially light in the distance measured along the trajectory (as well as in the geodesic one). In the case of infinite distance limits, we review a known classification of late-time asymptotic solutions, which always verify the extension of the conjecture whenever all relevant effects are taken into account. We also extend the analysis to the case of finite distance limits, where the analogous statement would require trajectories approaching the singularity to have a finite length. Surprisingly, we find this is not the case for the class of models under consideration. Moreover, the new solutions we find exhibit asymptotic accelerated expansion when approaching the boundary of moduli space.