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arXiv · 2206.06386

Observing nulling of primordial correlations via the 21 cm signal

Shyam Balaji·H. V. Ragavendra·Shiv K. Sethi·Joseph Silk·L. Sriramkumar
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Abstract

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.

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Shyam Balaji, H. V. Ragavendra, Shiv K. Sethi, Joseph Silk, L. Sriramkumar. 2023-01-04. Observing nulling of primordial correlations via the 21 cm signal. https://doi.org/10.1103/physrevlett.129.261301

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