Reconstruction of the Dark Energy Scalar Field Potential by Gaussian Process

Abstract

Dark energy is believed to be responsible for the acceleration of the Universe. In this paper, we reconstruct the dark energy scalar field potential V ( ϕ ) using the Hubble parameter H ( z ) through Gaussian process analysis. Our goal is to investigate dark energy using various H ( z ) data sets and priors. We find that the selection of the prior and the H ( z ) data set significantly affects the reconstructed V ( ϕ ). We compare two models, Power Law and Free Field, to the reconstructed V ( ϕ ) by computing the reduced chi-square. The results suggest that the models are generally in agreement with the reconstructed potential within a 3 σ confidence interval, except in the case of Observational H ( z ) data with the Planck 18 prior. Additionally, we simulate H ( z ) data to measure the effect of increasing the number of data points on the accuracy of reconstructed V ( ϕ ). We find that doubling the number of H ( z ) data points can improve the accuracy rate of reconstructed V ( ϕ ) by 5%–30%.

Keywords

• Dark energy
• Astronomy data analysis