Transient Crossing of Phantom divide line $w_{\Lambda}=-1$ under Gauss-Bonnet interaction

TL;DR

This paper demonstrates that in a cosmological model with Gauss-Bonnet-scalar interaction, the dark energy equation of state can smoothly cross the phantom divide line multiple times, fitting observational data well.

Contribution

It introduces a model allowing smooth double crossing of the phantom barrier, independent of the interaction sign, aligning with observational data.

Findings

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

The crossing occurs at late times, independent of interaction sign.

Luminosity distance matches $\Lambda$CDM up to redshift 3.5.

Abstract

Smooth double crossing of the phantom barrier $w_{\Lambda} = -1$ has been found possible in cosmological model with Gauss-Bonnet-scalar interaction, in the presence of background cold dark matter. Such crossing has been observed to be a sufficiently late time phenomena and independent of the sign of Gauss-Bonnet-scalar interaction. The luminosity distance versus redshift curve shows a perfect fit with the $\Lambda CDM$ model up to $z=3.5$.