An Informational Approach to Cosmological Parameter Estimation

Michelle Stephens, Marcelo Gleiser

Published 2019-05-17Version 1

We introduce a new approach for cosmological parameter estimation based on the information-theoretical Jensen-Shannon Divergence (JSD), calculating it for models in the restricted parameter space {H0, w0, wa}, where H0 is the value of the Hubble constant today, and w0 and wa 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 H0 tension between the Planck data and the local astronomical data by comparing the Lambda-CDM model with the wCDM and the w0waCDM dynamic dark energy models. We find agreement with other works using the standard Bayesian inference for parameter estimation, but, in addition, show that while the JSD is equally minimized for both values of H0 along the (w0,wa) plane, the lines of degeneracy are different for each value of H0. This allows for distinguishing between the two, once the value of either w0 or wa is known.