K-Inflation with a Dark Energy Coupling

TL;DR

This paper explores how a coupling between quintessence and the inflaton during k-inflation influences the speed of sound and the primordial power spectra, offering new insights into early universe dynamics.

Contribution

It introduces a model with power-law coupling between quintessence and inflaton in k-inflation, analyzing its effects on perturbation spectra and sound speed.

Findings

Coupling modifies the inflaton's sound speed.

Alterations in the power spectra due to the coupling.

Potential implications for early universe cosmology.

Abstract

It is usually thought that the quintessence as a fundamental scalar field was already present during the inflationary epoch. While there are various models in which the quintessence couples to other species, it is attractive to anticipate a coupling between the quintessence and the inflaton in the very early universe as well. We consider such a coupling in the context of k-inflation. The coupling function and the potential of the quintessence are chosen to be of power law forms. We show such a coupling affects the speed of sound for the inflaton field as well as the power spectra of perturbations.