An Informational Approach to Cosmological Parameter Estimation

We introduce a new approach for cosmological parameter estimation based on the information-theoretical Jensen-Shannon divergence (${\mathcal{D}}_{\mathrm{J}\mathrm{S}}$), calculating it for models in the restricted parameter space ${H_0, w_0, w_a}$,where$H_0$isthevalueoftheHubbleconstanttoday,and$w_0$and$w_a$ are dark energy parameters, with the other parameters held fixed at their best-fit values from the Planck 2018 data. As an application, we investigate the $H_0$ tension between the Planck temperature power spectrum data (TT) and the local astronomical data by comparing the $\mathrm{\Lambda }$CDM model with the $w$CDM and the $w_0{w}_a$CDM dynamic dark energy models. We find agreement with other works using the standard Bayesian inference for parameter estimation; in addition, we show that while the ${\mathcal{D}}_{\mathrm{J}\mathrm{S}}$ is equally minimized for both values of $H_0$ along the $(w_0,w_a)$ plane, the lines of degeneracy are different for each value of $H_0$. This allows for distinguishing between the two, once the value of either $w_0$ or $w_a$ is known.