Early Dark Energy can Resolve the Hubble Tension

Early dark energy (EDE) that behaves like a cosmological constant at early times (redshifts z≳3000) and then dilutes away like radiation or faster at later times can solve the Hubble tension. In these models, the sound horizon at decoupling is reduced resulting in a larger value of the Hubble parameter H_{0} inferred from the cosmic microwave background (CMB). We consider two physical models for this EDE, one involving an oscillating scalar field and another a slowly rolling field. We perform a detailed calculation of the evolution of perturbations in these models. A Markov Chain Monte Carlo search of the parameter space for the EDE parameters, in conjunction with the standard cosmological parameters,…

• NS
  National Science Foundation

  Award: 1818899
• NA
  National Aeronautics and Space Administration

  Awards: 80NSSC18K0728, NNX17AK38G
• SF
  Simons Foundation