Kinetic coupled tachyon: A dynamical system analysis

TL;DR

This paper introduces a kinetically coupled tachyon dark energy model where the scalar field interacts with matter, revealing a new attractor solution that can lead to accelerated expansion and address the coincidence problem.

Contribution

It presents a novel kinetically coupled tachyon model with a dynamical system analysis, uncovering a new attractor solution not found in uncoupled models.

Findings

Discovery of a new attractor solution with accelerated expansion

The model alleviates the coincidence problem

Identification of a stable scaling solution

Abstract

We present and examine a kinetically coupled tachyon dark energy model, where a tachyon scalar field interacts with the matter sector. More specifically, we deduce this cosmological setting from a generalised interacting dark energy model that allows for the kinetic term of the scalar field to couple to the matter species a priori in the action. A thorough dynamical system analysis and its cosmological implications unveil the appearance of a scaling solution which is also an attractor of the system, thanks to a novel critical point, with a period of accelerated expansion thereafter. This new solution, not present in the uncoupled case, has the enticing consequence of alleviating the coincidence problem.