Future observations of 21 cm emission using neutral hydrogen 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 spectrum and bispectrum. We find that the full scale Tianlai experiment and the Square Kilometre Array have the potential to improve on the sensitivity of current cosmic microwave background experiments by several orders of magnitude.

• Received 3 July 2016

DOI:https://doi.org/10.1103/PhysRevD.94.123518