Exponential Gravity
  We investigate a f(R) modification of gravity that is exponential in the
Ricci scalar R to explain cosmic acceleration. The steepness of this dependence
provides extra freedom to satisfy solar system and other curvature regime
constraints. With a parameter to alleviate the usual fine tuning of having the
modification strengthen near the present, the total number of parameters is
only one more than LCDM. The resulting class of solutions asymptotes to w=-1
but has no cosmological constant. We calculate the dynamics in detail, examine
the effect on the matter power spectrum, and provide a simple fitting form
relating the two.
