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arXiv · 2205.02478

Towards hybrid inflation with $n_s=1$ in light of Hubble tension and primordial gravitational waves

Gen Ye·Jun-Qian Jiang·Yun-Song Piao
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Abstract

Recently, it has been found that complete resolution of the Hubble tension might point to a scale-invariant Harrison-Zeldovich spectrum of primordial scalar perturbation, i.e. $n_s=1$ for $H_0\sim 73$km/s/Mpc. We show that for well-known slow-roll models, if inflation ends by a waterfall instability with respect to another field in the field space while inflaton is still at a deep slow-roll region, $n_s$ can be lifted to $n_s= 1$. A surprise of our result is that with pre-recombination early dark energy, chaotic $ϕ^2$ inflation, ruled out by Planck+BICEP/Keck in standard $Λ$CDM, can be revived, which is now well within testable region of upcoming cosmic microwave background B-mode experiments.

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Gen Ye, Jun-Qian Jiang, Yun-Song Piao. 2022-07-28. Towards hybrid inflation with $n_s=1$ in light of Hubble tension and primordial gravitational waves. https://doi.org/10.1103/physrevd.106.103528

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