Observational constraints on phantom power-law cosmology

TL;DR

This paper constrains phantom power-law cosmology using observational data, finding specific model parameters and predicting a future Big Rip singularity, with detailed analysis of dark energy properties.

Contribution

It provides the first comprehensive observational constraints on phantom power-law cosmology and reconstructs the associated dark energy potential.

Findings

Power-law exponent $eta \,\approx -6.51$ with tight uncertainties.

Big Rip occurs at approximately 104.5 Gyr from now.

Dark energy equation-of-state parameter $w_{DE} \,\approx -1.153$ at the Big Rip.

Abstract

We investigate phantom cosmology in which the scale factor is a power law, and we use cosmological observations from Cosmic Microwave Background (CMB), Baryon Acoustic Oscillations (BAO) and observational Hubble data, in order to impose complete constraints on the model parameters. We find that the power-law exponent is $\beta\approx-6.51^{+0.24}_{-0.25}$, while the Big Rip is realized at $t_s\approx104.5^{+1.9}_{-2.0}$ Gyr, in 1$\sigma$ confidence level. Providing late-time asymptotic expressions, we find that the dark-energy equation-of-state parameter at the Big Rip remains finite and equal to $w_{DE}\approx -1.153$, with the dark-energy density and pressure diverging. Finally, we reconstruct the phantom potential.