structural:reformatting, stylistic:style_transfer
Variable dark energy models

The density of dark energy might have varied in time during the history of the universe. Modern observational data allows us to estimate the present density of dark energy. Using baryon acoustic oscillations, it is possible to investigate the effect of dark energy in the history of the universe, and constrain parameters of the equation of state of dark energy. To that end, several models have been proposed. One of the most popular models is the Chevallier–Polarski–Linder model (CPL). Some other common models are (Barboza & Alcaniz. 2008), (Jassal et al. 2005), (Wetterich. 2004), and (Oztas et al. 2018).