부산대학교 도서관

The 21cm line emitted by neutral hydrogen (HI) during the Dark Ages carries imprints of pristine primordial correlations. In models of inflation driven by a single, canonical scalar field, we show that a phase of ultra-slow-roll can lead to a null in all the primordial correlations at a specific wavenumber $k_\textrm{dip}$. We consider scenarios wherein the null in the correlations occurs over wavenumbers $1 \lesssim k_\textrm{dip} \lesssim 10\,\mathrm{Mpc}^{-1}$, and examine the prospects of detecting such a damping in the HI signal due to the nulls at the level of power and bi-spectra in future observational missions.
Comment: v1: 10 pages, 5 figures; v2: 11 pages, 5 figures including supplementary material, published in Phys. Rev. Lett