AI 中文总结
研究原初黑洞霍金辐射对复合及哈勃张力的影响，通过Recfast软件模拟计算，发现特定PBH能量密度可增加H_0值以缓解哈勃张力，受灰体因子影响，拟合CMB后张力未全消，建议局部测量H_0。
AI 中文摘要
原初黑洞（PBHs）通过霍金辐射蒸发，发射高能光子并使其周围环境电离。作为暗物质密度贡献者，若宇宙中存在10^-18太阳质量的PBHs，它们会延迟复合并移动宇宙微波背景（CMB）的最后散射面。我们用Recfast软件进行复合模拟，计算解决哈勃张力所需的暗物质PBH分数。发现名义上宇宙PBH能量密度Ω_PBH ~ 10^-3Ω_C会使H_0值增加8.9%，足以完全消除早期和晚期观测之间的张力。此PBH分数受影响霍金辐射的灰体因子修正。此外，拟合CMB后，用当前PBH处方哈勃张力未完全消除。在主导暗物质种类的相关非引力性质未排除前，我们认为宇宙电离历史与标准LCDM宇宙学热历史匹配的假设太不可靠，不宜将膨胀率寄托于此，最好在z <~ 1处局部测量H_0。
英文摘要
Primordial black holes (PBHs) evaporate through Hawking radiation, emitting high-energy photons and ionising their surrounding environment. As contributors to the density of dark matter, Omega_C, if 10^-18 solar mass PBHs are present in the Universe they delay recombination and move the surface of last scattering of the cosmic microwave background (CMB). We perform recombination simulations using the software Recfast, and calculate the PBH fraction of dark matter required to resolve the Hubble tension. We find that nominally a cosmic PBH energy density of Omega_PBH ~ 10^-3 Omega_C would cause an 8.9% increase in the value of H_0, enough to entirely reduce the tension between the early- and late-time observations. This PBH fraction is modified by Gray Body Factors affecting Hawking radiation. Furthermore, also fitting the CMB leaves the Hubble tension not fully relieved with our present PBH prescription. Until relevant non-gravitational properties of the dominant dark matter species are ruled out, we suggest that the hypothesis that the ionisation history of the universe matches the thermal history of the standard LCDM cosmology is too precarious to hang the expansion rate on, and that it is better to measure H_0 locally at z <~ 1.
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