Reconstructing Horndeski models from the effective field theory of dark energy

Understand

Studying the effects of dark energy and modified gravity on cosmological scales has led to a great number of physical models being developed.

• The effective field theory (EFT) of cosmic acceleration allows an efficient exploration of this large model space, usually carried out on a phenomenological basis.
• However, constraints on such parametrized EFT coefficients cannot be trivially connected to fundamental covariant theories.
• In this paper we reconstruct the class of covariant Horndeski scalar-tensor theories that reproduce the same background dynamics and linear perturbations as a given EFT action.