Cosmological Implications of the Effective Field Theory of Cosmic
  Acceleration
  We consider cosmological constraints arising from the background expansion
history on the ef- fective field theory of cosmic acceleration, a theoretical
framework that allows for a unified way to classify both models of dark energy
and modified gravity within the linear regime. In the Einstein frame, the most
general action for the background can be written in terms of a canonical scalar
field which is non-minimally coupled to matter. The leading corrections to the
action are expressible through a quartic kinetic term, and scalar couplings to
a Gauss-Bonnet curvature term and the Einstein tensor. We determine the
implications of the terms in this general action for the predicted expansion
history in the context of dynamical attractors. We find that each modifies the
matter dominated and/or accelerative eras in ways that allow us to place
cosmological constraints on them. We present current constraints on the
effective action using the latest Type Ia supernovae, Cosmic Microwave
Background, and Baryonic Acoustic Oscillation data. This includes finding that
the scalar field EFT with a coupled Gauss-Bonnet term and the data are
significantly discrepant.
