论文标题
来自原始黑洞的宇宙的引力波
Gravitational waves from a universe filled with primordial black holes
论文作者
论文摘要
超光原始黑洞，带有质量$ m_ \ mathrm {pbh} <10^9 \ mathrm {g} $，蒸发在大爆角核合成之前，因此不能直接受到约束。但是，它们可以如此丰富，以至于它们在短暂的时期内占主导地位（在通过霍金蒸发加热宇宙之前）。如果发生这种情况，它们会支持小尺度上的巨大宇宙学波动，从而通过二阶效应诱导引力波的产生。与原始黑洞相反，这些引力波在蒸发后生存，因此可用于限制这种情况。在这项工作中，我们表明，对于诱导的引力波不导致反应问题，形成时黑洞的相对丰度，表示为$ω__\ mathrm {pbh，f} $，应该是$ω______________\ MATHRM {PBH，F} <10^{ - 4}（M_ \ Mathrm {PbH}/10^9 \ Mathrm {G}）^{ - 1/4} $。特别是，排除原始黑洞在其形成时间时占主导地位的场景都被排除在外（鉴于$ M_ \ Mathrm {pbh}> 10 \，\ Mathrm {g} $以$ρ^{1/4} <10^{16} <10^{16} {16} \ Mathrm {geev} $进行通货膨胀继续进行。这为超光原始黑洞设定了第一个约束。
Ultra-light primordial black holes, with masses $m_\mathrm{PBH}<10^9\mathrm{g}$, evaporate before big-bang nucleosynthesis and can therefore not be directly constrained. They can however be so abundant that they dominate the universe content for a transient period (before reheating the universe via Hawking evaporation). If this happens, they support large cosmological fluctuations at small scales, which in turn induce the production of gravitational waves through second-order effects. Contrary to the primordial black holes, those gravitational waves survive after evaporation, and can therefore be used to constrain such scenarios. In this work, we show that for induced gravitational waves not to lead to a backreaction problem, the relative abundance of black holes at formation, denoted $ Ω_\mathrm{PBH,f} $, should be such that $ Ω_\mathrm{PBH,f} <10^{-4}(m_\mathrm{PBH}/10^9\mathrm{g})^{-1/4}$. In particular, scenarios where primordial black holes dominate right upon their formation time are all excluded (given that $m_\mathrm{PBH}>10\, \mathrm{g}$ for inflation to proceed at $ρ^{1/4}<10^{16}\mathrm{GeV}$). This sets the first constraints on ultra-light primordial black holes.
