A Two-field Dilaton Model of Dark Energy

TL;DR

This paper explores a two-field dark energy model combining a dilaton and a phantom field, demonstrating a stable late-time attractor solution where the equation of state crosses the cosmological constant boundary, aligning with observations.

Contribution

It introduces a novel two-field dark energy model with a dilaton and phantom field, analyzing its stability and evolution, and showing the crossing of the equation of state from above to below -1.

Findings

Phantom-dominated scaling solution is stable and late-time attractor.

The equation of state $w$ transitions from greater than -1 to less than -1.

Model aligns with recent observational data.

Abstract

We investigate the cosmological evolution of a two-field model of dark energy where one is a dilaton field with canonical kinetic energy and the other is a phantom field with a negative kinetic energy term. A phase-plane analysis shows that the phantom-dominated scaling solution is the stable late-time attractor of this type of models. We find that during the evolution of the universe, the equation of state $w$ changes from $w > -1$ to $w <-1$, which is consistent with the recent observations.