Treading the Tightrope: Perturbative Solutions to Information Extraction

Modifications to gravity and the dark sector can provide interesting alternatives to ΛCDM. Cosmology offers an ever improving arena to test such modifications and within the next 10 years we will have extremely precise observations with which to test our understanding of the cosmos. This being said, there is a lot of preparation on the theory side that needs to be done in order to maximise the unbiased information we can get from such precise astronomical observations. In this talk I will go over standard perturbation theory, its application to the large scale structure of the universe, its merits and drawbacks. I will then discuss various recent developments on optimising the perturbative framework for the next generation of surveys, with particular emphasis on departures from ΛCDM.