An effective description of dark matter and dark energy in the mildly
  non-linear regime
  In the next few years, we are going to probe the low-redshift universe with
unprecedented accuracy. Among the various fruits that this will bear, it will
greatly improve our knowledge of the dynamics of dark energy, though for this
there is a strong theoretical preference for a cosmological constant. We assume
that dark energy is described by the so-called Effective Field Theory of Dark
Energy, which assumes that dark energy is the Goldstone boson of time
translations. Such a formalism makes it easy to ensure that our signatures are
consistent with well-established principles of physics. Since most of the
information resides at high wavenumbers, it is important to be able to make
predictions at the highest wavenumber that is possible. The Effective Field
Theory of Large-Scale Structure (EFTofLSS) is a theoretical framework that has
allowed us to make accurate predictions in the mildly non-linear regime. In
this paper, we derive the non-linear equations that extend the EFTofLSS to
include the effect of dark energy both on the matter fields and on the biased
tracers. For the specific case of clustering quintessence, we then
perturbatively solve to cubic order the resulting non-linear equations and
construct the one-loop power spectrum of the total density contrast.
