Orateur
Description
In this talk, I will introduce a novel class of interacting vacuum dark energy models, based on recasting the equation of state originally developed in the context of lattice kinetic theory by Shan & Chen (1993) as the coupling between the vacuum and cold dark matter (CDM). This coupling allows the vacuum to evolve and is nonlinear around a characteristic energy scale ρ∗, changing into a linear coupling with a typical power law evolution at scales much lower and much higher than ρ∗. I will illustrate the various possible models that can arise from the Shan--Chen coupling, with several different behaviours at both early and late times depending on the values of the model parameters selected. I will show the first observational constraints obtained on these models, focusing on those in which the nonlinearity of the coupling is relevant at late times. I will show how current observational data is compatible with the Shan--Chen interacting vacuum cosmology but that the H0 and σ8 tensions remain present in this scenario.
