Primordial black holes and secondary gravitational waves from natural inflation

Abstract

Qing Gao, 2, ∗ Yungui Gong, 2, † and Zhu Yi ‡ School of Physical Science and Technology, Southwest University, Chongqing 400715, China MOE Key Laboratory of TianQin Project, Sun Yat-sen University, Zhuhai 519082, China School of Physics, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China Department of Astronomy, Beijing Normal University, Beijing 100875, China Abstract The production of primordial black hole (PBH) dark matter (DM) and the generation of scalar induced secondary gravitational waves by using the enhancement mechanism with a peak function in the non-canonical kinetic term in natural inflation is discussed. We show explicitly that the power spectrum for the primordial curvature perturbation is enhanced at 1012 Mpc−1, 108 Mpc−1 and 105 Mpc−1, the production of PBH DM with peak masses around 10−13 M , the earth’s mass and the stellar mass, and the generation of scalar induced gravitational waves (SIGWs) with peak frequencies around mHz, 10−6 Hz and nHz, respectively. The PBHs with the mass scale 10−13 M can make up almost all the DM and the associated SIGWs is testable by spaced based gravitational wave observatory.