大额外维度下作为宏观暗物质的微观原初黑洞

本文研究了在具有大额外维度的Arkani-Hamed-Dimopoulos-Dvali（ADD）框架下，原初黑洞（PBH）与辐射的耦合演化。研究表明，微观原初黑洞可以通过辐射吸积实现质量的快速增长，从而在物质辐射等量时期达到宏观尺度。这一机制显著降低了原初黑洞作为暗物质候选者所需的初始坍缩比例。

arXiv:2604.14871v2 Announce Type: replace Abstract: We study the coupled cosmological evolution of primordial black holes (PBHs) and radiation in the Arkani-Hamed-Dimopoulos-Dvali (ADD) framework with $n$ large extra dimensions and a fundamental gravity scale $M_\star$ at the TeV scale. For PBHs with horizon radius smaller than the compactification scale, the higher-dimensional geometry implies a larger horizon size at fixed mass and therefore a suppressed Hawking temperature. As a result, radiation accretion can overcome evaporation in the early Universe and drive a ``runaway'' phase of rapid mass growth. By numerically solving the coupled mass and energy-density evolution equations, we show that for $n \geq 2$ initially microscopic PBHs with initial mass $M_i \gtrsim 10^{12}\,$g can grow by many orders of magnitude and potentially reach macroscopic, even solar-mass, scales by matter-radiation equality. We determine the critical initial abundance $\beta_{\rm crit}$ required for PBHs to account for the observed dark matter density and find that extra dimensions dramatically lower this threshold, allowing viable scenarios with $\beta_{\rm crit}\sim 10^{-44}$. This identifies a previously unexplored region of parameter space in which the dark matter abundance is achieved through dynamical mass growth rather than large initial collapse fractions.