Distinguishing f(R) gravity with cosmic voids
  We use properties of void populations identified in N-body simulations to
forecast the ability of upcoming galaxy surveys to differentiate models of f(R)
gravity from \Lambda CDM cosmology. We analyze simulations designed to mimic
the densities, volumes, and clustering statistics of upcoming surveys, using
the public VIDE toolkit. We examine void abundances as a basic probe at
redshifts 1.0 and 0.4. We find that stronger f(R) coupling strengths produce
voids up to ~20% larger in radius, leading to a significant shift in the void
number function. As an initial estimate of the constraining power of voids, we
use this change in the number function to forecast a constraint on the coupling
strength of $\Delta f_{R_{0}} = 10^{-5}$.
