Higgs-Dilaton Cosmology: From the Early to the Late Universe
Zenhaeusern, Daniel (EPFL Lausanne, Switzerland)

We consider a minimal scale-invariant extension of the Higgs-Inflation model. The resulting model is able to describe not only an inflationary stage, but also a late period of dark energy domination. All parameters can be fixed by inflationary physics, allowing to make specifc predictions for any subsequent period. In particular, we derive a relation between the tilt of the primordial spectrum of scalar fluctuations, n_s, and the present value of the equation of state parameter of dark energy, ω_DE. Within the Higgs-Dilaton scenario we find upper bounds for the scalar tilt, n_s < 0.97 and for the scalar-to-tensor ratio, r < 0.0035, which will be critically tested by the results of the Planck mission. For the equation of state of dark energy, the model predicts ω_DE > −1. The relation between n_s and ω_DE allows us to translate the current observational constraints on n_s into a prediction for the dark energy equation of state, 0 < 1 + ω_DE < 0.0014, which will be rather challenging to test in the near future.