Observing Nulling of Primordial Correlations via the 21-cm Signal

Shyam Balaji, H. V. Ragavendra, Shiv K. Sethi, Joseph Silk, and L. Sriramkumar

Phys. Rev. Lett. 129, 261301 – Published 22 December 2022

Abstract

The 21-cm 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 wave number $k_{dip}$ . We consider scenarios wherein the null in the correlations occurs over wave numbers $1 ≲ k_{dip} ≲ 10 {Mpc}^{- 1}$ , and examine the prospects of detecting such a damping in the HI signal due to the nulls at the level of power and bispectra in future observational missions.

Received 25 June 2022
Revised 21 October 2022
Accepted 22 November 2022

DOI:https://doi.org/10.1103/PhysRevLett.129.261301

Physics Subject Headings (PhySH)

Cosmology Evolution of the Universe Inflation Radio, microwave, & sub-mm astronomy

Gravitation, Cosmology & Astrophysics

Authors & Affiliations

Shyam Balaji ^1,*, H. V. Ragavendra ^2,†, Shiv K. Sethi^3,4,‡, Joseph Silk^5,§, and L. Sriramkumar ^4,∥

¹Laboratoire de Physique Théorique et Hautes Energies (LPTHE), UMR 7589 CNRS and Sorbonne Université, 4 Place Jussieu, F-75252, Paris, France
²Department of Physical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, Nadia 741246, India
³Raman Research Institute, C. V. Raman Avenue, Sadashivanagar, Bengaluru 560080, India
⁴Centre for Strings, Gravitation and Cosmology, Department of Physics, Indian Institute of Technology Madras, Chennai 600036, India
⁵Institut d’Astrophysique de Paris, UMR 7095 CNRS & Sorbonne Université, 98 bis boulevard Arago, F-75014 Paris, France

^*sbalaji@lpthe.jussieu.fr
^†ragavendra.pdf@iiserkol.ac.in
^‡sethi@rri.res.in
^§silk@iap.fr
^∥sriram@physics.iitm.ac.in

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Issue

Vol. 129, Iss. 26 — 23 December 2022

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