Characterizing the linear growth rate of cosmological density
  perturbations in an f(R) model
  We investigate the linear growth rate of cosmological matter density
perturbations of a viable f(R) model both numerically and analytically. We find
that the growth rate in the scalar-tensor regime can be characterized by a
simple analytic formula. We also investigate a prospect of constraining the
Compton wavelength scale of the f(R) model with a future weak lensing survey.
