K-mouflage Cosmology: Formation of Large-Scale Structures

Understand

We study structure formation in K-mouflage cosmology whose main feature is the absence of screening effect on quasilinear scales.

• We show that the growth of structure at the linear level is affected by both a new time dependent Newton constant and a friction term which depend on the background evolution.
• These combine with the modified background evolution to change the growth rate by up to ten percent since $z\sim 2$.
• At the one loop level, we find that the nonlinearities of the K-mouflage models are mostly due to the matter dynamics and that the scalar perturbations can be treated at tree level.