Deus ex $H_0$ -- Is evidence for dynamical dark energy conditioned on early cosmology?

Abstract

Some free-form reconstructions of the dark energy equation of state suggest that dynamical dark energy is the only explanation for the observed data. In this letter we argue that early Universe solutions to the Hubble tension (around or before recombination) generically cause the evidence for this claim to strongly reduce, establishing a tight connection between the early and late cosmology. In particular, the level of evidence for dynamical dark energy depends on the parameters $H_0 r_\mathrm{d}$ and $Ω_\mathrm{m}$ and early universe solutions typically push towards higher values of $H_0 r_\mathrm{d}$ and lower values of $Ω_\mathrm{m}$, where such evidence is reduced.