Self-Tracking Solutions for Asymptotic Scalar Fields

TL;DR

This paper investigates scalar field dynamics with exponential potentials, revealing self-tracking solutions where scalar perturbations mimic radiation, with implications for string cosmology and early universe conditions.

Contribution

It demonstrates the existence of self-tracking solutions for scalar fields without background fluids, using analytic and numerical methods, including CosmoLattice simulations.

Findings

Self-perturbations act as an effective radiation background.

Validated solutions through analytic and numerical approaches.

Implications for initial perturbations in string cosmology.

Abstract

We explore the dynamics of pure scalar fields rolling on an exponential potential in the absence of any additional background fluid and demonstrate the existence of self-tracking solutions in which the self-perturbations of the scalar field act as an effective radiation background. The validity of these solutions is demonstrated through both analytic techniques and numerical simulations using CosmoLattice. We discuss applications to string cosmologies with significant trans-Planckian field excursions between inflation and BBN, including the required initial level of scalar perturbations to avoid overshoot.