Speaker
Mario Ballardini
(University of Bologna)
Description
We study the predictions for structure formation in an induced gravity
dark energy model
with a quartic potential. By developing a dedicated Einstein-Boltzmann
code, we study
self-consistently the dynamics of homogeneous cosmology and of linear
perturbations
without using any parametrization,
accurately recovering the quasi-static analytic approximation in the
matter dominated era.
We use CMB anisotropies data and a compilation of BAO data to constrain
the coupling
$\gamma$ to the Ricci curvature and the other cosmological parameters.
By connecting the gravitational constant in the Einstein equation to the one
measured in a Cavendish-like experiment, we find $\gamma < 0.0012$ at 95 %
confidence level with Planck 2013 and BAO data, and present the
updated Planck 2015 constraint. Because of a degeneracy between $\gamma$
and the Hubble constant $H_0$, we show how larger values for $\gamma$ are
allowed, but not preferred at a significant statistical level,
when local measurements of $H_0$ are combined in the analysis with Planck data.
We also extend the analysis and constraints to a simple monomial potential
with a positive
exponent.
Primary author
Mario Ballardini
(University of Bologna)
