Reconstruction of Primordial Power Spectrum of curvature perturbation from the merger rate of Primordial Black Hole Binaries

Abstract

The properties of primordial curvature perturbations on small scales are still unknown while those on large scales have been well probed by the observations of the cosmic microwave background anisotropies and the large scale structure. In this paper, we propose the reconstruction method of primordial curvature perturbations on small scales through the merger rate of binary primordial black holes, which could form from large primordial curvature perturbation on small scales.

A qualitative study on gender barriers to access cataract surgery in rural Gurugram, Haryana, India

“…Despite of the fact that the large-scale universe and inhomogenities are consistent with the Planck's ΛCDM predictions, the small-scale large overdensities at some comoving wavenumber k ≫ k * = k CM B could arise from large density fluctuations during inflation [18][19][20][21]. Upon exiting the horizon, these fluctuations gets freeze out and once they enter inside the horizon, they gets collapse.…”

Enhanced curvature perturbation and primordial black hole formation in two-stage inflation with a break

“…In particular, for asteroid mass (ranging from 10 −16 M ⊙ to 10 −12 M ⊙ ) PBHs, they may constitute all the CDM [17][18][19][20]. Second, PBHs also provide a natural explanation for the high masses and low spins of binary black hole (BBH) [21][22][23][24][25][26][27][28][29], inferred from the past three runs of GW observations by LIGO-Virgo and LIGO-Virgo-KAGRA collaborations [30][31][32]. The recently discovered signal of a GW background by several pulsar timing array (PTA) collaborations at 10 −9 ∼ 10 −8 Herz band [33][34][35][36] has drawn a widespread attention [37][38][39][40][41][42][43][44][45][46][47], it indicates the existence of sub-solar mass PBHs, which may be detected by microlensing observations [17,[48][49][50][51][52][53][54][55].…”