https://doi.org/10.1140/epjc/s10052-025-15115-8
Regular Article - Theoretical Physics
Study of primordial non-Gaussianity 
and 
with the cross-correlations between the scalar-induced gravitational waves and the cosmic microwave background
1
Department of Applied Physics, College of Science, China Agricultural University, 17 Qinghua East Road, Haidian District, 100083, Beijing, China
2
School of Physics, Hangzhou Normal University, No. 2318 Yuhangtang Road, Yuhang District, 311121, Hangzhou, China
3
Theoretical Physics Division, Institute of High Energy Physics, Chinese Academy of Sciences, 19B Yuquan Road, Shijingshan District, 100049, Beijing, China
4
School of Physics, University of Chinese Academy of Sciences, 19A Yuquan Road, Shijingshan District, 100049, Beijing, China
5
Division of Science, National Astronomical Observatory of Japan (NAOJ), and SOKENDAI, 2-21-1 Osawa, 181-8588, Mitaka, Tokyo, Japan
6
Theory Center, IPNS and QUP (WPI), KEK, 1-1 Oho, 305-0801, Tsukuba, Ibaraki, Japan
7
Kavli IPMU (WPI), UTIAS, The University of Tokyo, 277-8583, Kashiwa, Chiba, Japan
a
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Received:
29
April
2025
Accepted:
24
November
2025
Published online:
10
December
2025
Abstract
The stochastic gravitational-wave background originating from cosmic sources contains vital information about the early universe. In this work, we comprehensively study the cross-correlations between the energy-density anisotropies in scalar-induced gravitational waves and the temperature anisotropies and polarization in the cosmic microwave background. In our analysis of the angular power spectra for these cross-correlations, we consider all contributions of the local-type primordial non-Gaussianity and that can lead to large anisotropies. We show that the angular power spectra are highly sensitive to primordial non-Gaussianity. Furthermore, we project the sensitivity of future gravitational-wave detectors to detect such signals and, consequently, measure the primordial non-Gaussianity.
© The Author(s) 2025
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Funded by SCOAP3.
