MR. SEBASTIAN SEEHARS

To shed light on dark energy and dark matter, a large number of experiments have been performed and combined to constrain cosmological models. Comparing these parameter constraints is crucial for finding ways to challenge existing models with observations. We present the Kullback-Leibler divergence as a measure for the differences between the posterior distributions of the model parameters from a pair of experiments. We distinguish contributions from the reduction of statistical errors and the “surprise" corresponding to a significant shift of the parameters' central values. Applying it to a historical sequence of CMB experiments, we discuss how this technique provides a useful tool for both quantifying the constraining power of data from cosmological probes and detecting tensions between experiments.