No Run Gravity
  Considering the dark energy/gravity landscape if next generation surveys of
galaxies, cosmic microwave background radiation, and gravitational waves do not
find clear modification of gravity, we develop No Run Gravity as a
counterexample to the conclusion that this would imply general relativity with
an expansion history described by an equation of state $w(z)$. No Run Gravity
is a cubic Horndeski theory with a constant Planck mass, no gravitational slip,
and no modification of gravitational waves, but a rich phenomenology beyond
$w(z)$. We calculate the evolution of gravitational strength, sound speed, and
cosmic growth within the theory and project sensitivities for upcoming DESI
redshift space distortion data.
