Smooth crossing of $w_{\Lambda} = -1$ line in a single scalar field model

TL;DR

This paper demonstrates that a single scalar field in a generalized k-essence model can smoothly cross the phantom divide line $w_{\Lambda}=-1$ without pathologies, occurring as a late-time transient.

Contribution

It shows the possibility of smooth $w_{\Lambda}=-1$ crossing in a simple single scalar field model with cold dark matter, expanding understanding of dark energy dynamics.

Findings

Smooth crossing of $w_{\Lambda}=-1$ is achievable in the model.

Crossing occurs as a late-time transient.

No pathological behavior observed during crossing.

Abstract

Smooth double crossing of the phantom divide line $w_{\Lambda}=-1$ has been found possible with a single minimally coupled scalar field for the most simple form of generalized k-essence cosmological model, in the presence of background cold dark matter. Such crossing is a sufficiently late time transient phenomena and does not have any pathological behaviour.