# An Informational Approach to Cosmological Parameter Estimation

## TL;DR

This paper presents a novel information-theoretical method using Jensen-Shannon divergence for cosmological parameter estimation, applied to address the H0 tension by comparing models with different dark energy parameters.

## Contribution

It introduces an informational approach to cosmological parameter estimation and demonstrates its effectiveness in distinguishing H0 values in dark energy models.

## Key findings

- Jensen-Shannon divergence aligns with Bayesian inference results.
- Degeneracy lines differ for H0 values in the parameter space.
- Method can differentiate H0 values once one dark energy parameter is known.

## Abstract

We introduce a new approach for cosmological parameter estimation based on the information-theoretical Jensen-Shannon divergence (${\cal D}_{\rm JS}$), calculating it for models in the restricted parameter space $\{H_0, w_0, w_a\}$, where $H_0$ is the value of the Hubble constant today, 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 $\Lambda$CDM model with the $w$CDM and the $w_0w_a$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 ${\cal D}_{\rm JS}$ 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.