Model-independent probes of dark sector physics

The nature of the dark sector is unknown, and numerous dark matter models have been proposed for dark matter. It can be time-consuming to reanalyze cosmic microwave background (CMB) data one model at a time, so it will be more efficient to develop a model-independent approach. In this work, we test such an approach using specific models as a benchmark. The Wess Zumino Dark Radiation (WZDR) model and the Chameleon Early Dark Energy (CEDE) model are promising solutions for the Hubble tension between local and CMB-based measurements. We aim to test these models using the generalized dark matter (GDM) methods and principal component analysis (PCA). We compute the GDM equation of state and effective sound speed for the dark cosmological fluid, which only interacts with photons and baryons through gravitational interactions. We then project the models onto the principal components of the cosmological dark fluid. In the future, we will apply this method to real CMB data in order to obtain constraints to these models through a model-independent approach.