Just a drop of MARC -- Magnetism, Acceleration and Reionisation of the Cosmos

In this manuscript, I give a summary of my research in physical cosmology, covering mainly the topics of dark energy revealed by the large scale cosmic structures, the origin of magnetic fields at very large scales, and the possibilities to probe the history of reionization by the cross-correlations of the cosmic microwave background and the redshifted 21cm hydrogen line.