Minimal description for Large-Scale Structure in general scalar-tensor theories

Minimal description for Large-Scale Structure in general scalar-tensor theories

In this talk I shall discuss the properties of linear perturbations of scalar-tensor theories belonging to the Horndeski class of actions whilst evolving on a cosmological background. To do so, I will discuss the physical interpretation of five independent functions of time, which are sufficient in order to describe the exact linear evolution of these models. Finally, I will explain how to constrain these functions by observations and how to reduce the full theory to well-known models.