A Vacuum Phase Transition Solves $H_0$ Tension
  Taking the Planck cosmic microwave background data and the more direct Hubble
constant measurement data as unaffected by systematic offsets, the values of
the Hubble constant $H_0$ interpreted within the $\Lambda$CDM cosmological
constant and cold dark matter cosmological model are in $\sim 3.3 \sigma$
tension. We show that the Parker vacuum metamorphosis model, physically
motivated by quantum gravitational effects and with the same number of
parameters as $\Lambda$CDM, can remove the $H_0$ tension, and can give an
improved fit to data (up to $\Delta\chi^2=-7.5$). It also ameliorates tensions
with weak lensing data and the high redshift Lyman alpha forest data. We
separately consider a scale dependent scaling of the gravitational lensing
amplitude, such as provided by modified gravity, neutrino mass, or cold dark
energy, motivated by the somewhat different cosmological parameter estimates
for low and high CMB multipoles. We find that no such scale dependence is
preferred.
