Scalar Field Dark Energy Model Via Observational Constraints

Abstract

This paper proposes a new scalar field cosmological model aimed at studying the late-time acceleration of the universe, based on a parametrization of the deceleration parameter. The main objective is to constrain fundamental cosmological parameters by integrating the latest measurements of the Hubble parameter from various observational datasets, including BAO, BAO \(+\) R19, CC \(+\) SC \(+\) BAO, and CC \(+\) SC \(+\) BAO \(+\) R19 from recent galaxy surveys. With a redshift range covering \(0.106<z<2.33\), and incorporating the newest Hubble constant measurements from Riess et al. in 2019, we acquire best-fit parameter values for \(H_{0}\) and \(r_{d}\). It is noteworthy that within late-time observations of \(H_{0}\), we observe a significant discrepancy, reproducing the reported \(H_{0}\) tension. While our model is in good agreement with both the joint analysis and analysis with R19, discrepancies arise when BAO and BAO with R19 datasets are gradually included. Our model provides an excellent fit to the observed data and is consistent with the standard \(\Lambda\)CDM paradigm at higher redshifts. However, the most interesting aspect is the prediction of future super-accelerated expansion, in contrast to the de Sitter phase predicted by the \(\Lambda\)CDM model. The unique behavior of the jerk parameter also hints at new dynamics as ccompared to traditional cosmological models.