https://cea.hal.science/cea-02929292Brax, PhilippePhilippeBraxIPHT - Institut de Physique Théorique - UMR CNRS 3681 - CEA - Commissariat à l'énergie atomique et aux énergies alternatives - Université Paris-Saclay - CNRS - Centre National de la Recherche ScientifiqueValageas, PatrickPatrickValageasIPHT - Institut de Physique Théorique - UMR CNRS 3681 - CEA - Commissariat à l'énergie atomique et aux énergies alternatives - Université Paris-Saclay - CNRS - Centre National de la Recherche ScientifiqueK-mouflage Cosmology: Formation of Large-Scale StructuresHAL CCSD2014[PHYS.ASTR.CO] Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO]Savelli, BrunoBLANC - Les grandes structures de l'univers au delà le l'ordre linéaire - - COSMO@NLO2012 - ANR-12-BS05-0002 - BLANC - VALID - INVISIBLES - INVISIBLES - - EC:FP7:PEOPLE2012-04-01 - 2016-03-31 - 289442 - VALID - 2020-09-07 16:32:022023-03-24 14:53:182020-09-07 16:33:06enJournal articleshttps://cea.hal.science/cea-02929292/document10.1103/PhysRevD.90.023508application/pdf1We study structure formation in K-mouflage cosmology whose main feature is the absence of screening effect on quasi-linear scales. We show that the growth of structure at the linear level is both affected by 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 non-linearities of the K-mouflage models are mostly due to the matter dynamics and that the scalar perturbations can be treated at tree level. We also study the spherical collapse in K-mouflage models and show that the critical density contrast deviates from its $\Lambda$-CDM value and that, as a result, the halo mass function is modified for large masses by an order one factor. Finally we consider the deviation of the matter spectrum from $\Lambda$-CDM on non-linear scales where a halo model is utilised. We find that the discrepancy peaks around $1\ h{\rm Mpc}^{-1}$ with a relative difference which can reach fifty percent. Importantly, these features are still true at larger redshifts, contrary to models of the chameleon-$f(R)$ and Galileon types.