Precise measurements of inflationary features with 21 cm observations

TL;DR

Future 21 cm observations, especially with Tianlai and SKA, could vastly improve detection of inflationary features in the primordial power spectrum and bispectrum, surpassing current CMB constraints.

Contribution

This paper forecasts the potential of upcoming 21 cm intensity mapping experiments to detect specific inflationary features with unprecedented sensitivity.

Findings

Tianlai and SKA can significantly outperform current CMB experiments in detecting inflationary features.

21 cm surveys provide three-dimensional data, enhancing the search for primordial features.

Forecasts indicate these experiments could detect resonant and step inflation models.

Abstract

Future observations of 21~cm emission using HI intensity mapping will enable us to probe the large scale structure of the Universe over very large survey volumes within a reasonable observation time. We demonstrate that the three-dimensional information contained in such surveys will be an extremely powerful tool in searching for features that were imprinted in the primordial power spectrum and bispectrum during inflation. Here we focus on the "resonant" and "step" inflation models, and forecast the potential of upcoming 21~cm experiments to detect these inflationary features in the observable power- and bispectrum. We find that the full scale Tianlai experiment and the Square Kilometre Array (SKA) have the potential to improve on the sensitivity of current Cosmic Microwave Background (CMB) experiments by several orders of magnitude.