Early Dark Energy Can Resolve The Hubble Tension. (arXiv:1811.04083v1 [astro-ph.CO])
<a href="http://arxiv.org/find/astro-ph/1/au:+Poulin_V/0/1/0/all/0/1">Vivian Poulin</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Smith_T/0/1/0/all/0/1">Tristan L. Smith</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Karwal_T/0/1/0/all/0/1">Tanvi Karwal</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kamionkowski_M/0/1/0/all/0/1">Marc Kamionkowski</a>
Early dark energy (EDE) that behaves like a cosmological constant at early
times (redshifts $zgtrsim3000$) and then decays 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, identifies regions in which $H_0$ inferred from Planck
CMB data agrees with the SH0ES local measurement. In these cosmologies, current
baryon acoustic oscillation and supernova data are described as successfully as
in $Lambda$CDM while the fit to Planck data is slightly improved. Future CMB
and large-scale-structure surveys will further probe this scenario.
Early dark energy (EDE) that behaves like a cosmological constant at early
times (redshifts $zgtrsim3000$) and then decays 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, identifies regions in which $H_0$ inferred from Planck
CMB data agrees with the SH0ES local measurement. In these cosmologies, current
baryon acoustic oscillation and supernova data are described as successfully as
in $Lambda$CDM while the fit to Planck data is slightly improved. Future CMB
and large-scale-structure surveys will further probe this scenario.
http://arxiv.org/icons/sfx.gif
