The screening Horndeski cosmologies

Understand

We present a systematic analysis of homogeneous and isotropic cosmologies in a particular Horndeski model with Galileon shift symmetry, containing also a $\Lambda$-term and a matter.

• The model, sometimes called Fab Five, admits a rich spectrum of solutions.
• Some of them describe the standard late time cosmological dynamic dominated by the $\Lambda$-term and matter, while at the early times the universe expands with a constant Hubble rate determined by the value of the scalar kinetic coupling.
• For other solutions the $\Lambda$-term and matter are screened at all times but there are nevertheless the early and late accelerating phases.