Vainshtein Screening in Bimetric Cosmology
  We demonstrate that the instabilities in linear cosmological perturbations in
bimetric theory are the manifestation of the non-linear Vainshtein mechanism on
an FRW background. The spin-2 mass serves as the cosmological Vainshtein scale
in this case. This allows us to quantitatively address early universe
cosmology. In particular, in a global analysis, we study data from the cosmic
microwave background radiation and local measurements of the Hubble flow. We
show that bimetric cosmology resolves the discrepancy in the local and
early-time measurements of the Hubble scale via an effective phantom dark
energy component.
