Primordial black holes from second order density perturbations as probes of the small-scale primordial power spectrum
- Resource Type
- Working Paper
- Authors
- Kuang, Yu-Ting; Zhou, Jing-Zhi; Chang, Zhe; Zhang, Xukun; Zhu, Qing-Hua
- Source
- Subject
- Astrophysics - Cosmology and Nongalactic Astrophysics
General Relativity and Quantum Cosmology
- Language
We investigate the second order energy density perturbation $\delta^{(2)}$ induced by small-scale Gaussian and local-type non-Gaussian primordial curvature perturbations. The relative abundance of primordial black hole is calculated in terms of the probability density function of total energy density perturbation $\delta_r=\delta^{(1)}+\frac{1}{2}\delta^{(2)}$. The effects of second order density perturbation greatly reduce the upper bounds of small-scale power spectra of primordial curvature perturbations by one to two orders of magnitude. For log-normal primordial power spectrum, its amplitude $A_{\zeta}$ is constrained to be about $A_{\zeta}\sim 3\times10^{-3}$. And for local-type non-Gaussianity with $f_{\mathrm{NL}}=10$, the upper bound of $A_{\zeta}$ is about $2.5\times10^{-4}$.
Comment: 5 pages, 4 figures