Non-linear dark matter collapse under diffusion
  Diffusion is one of the physical processes allowed for describing the large
scale dark matter dynamics. At the same time, it can be seen as a possible
mechanism behind the interacting cosmologies. We study the non-linear spherical
"top-hat" collapse of dark matter which undergoes velocity diffusion into a
solvent dark energy field. We show constraints on the maximum magnitude allowed
for the dark matter diffusion. Our results reinforce previous analysis
concerning the linear perturbation theory.
