Physics Theory Seminar with Hasti Khoraminezhad On the Relative Baryon-CDM Perturbation Measurements in Cosmology
Baryons and Cold Dark Matter (CDM) as two dominant matter components of our Universe undergo different evolution due to the photon pressure before the cosmological recombination era. This causes relative perturbations between these two components in our Universe. These perturbations (called baryon-CDM perturbations) exist both in the density and peculiar velocity of the two fields and are commonly neglected in the studies of cosmological structure formation. However, taking them into account might become very important in the era of high-precision cosmology. In this talk, I will give a brief overview of our current understanding of the structure formation in the Universe, the progress in the cosmological concordance model, and also the questions we still have on each of the ingredients of the standard model. Then I will briefly show how numerical simulations can predict accurately the non-linear evolution of our Universe and how baryon-CDM perturbations can help us to refine this understanding.