标题： 重新审视在轻原初黑洞视角下的弦理论启发的运行真空模型 显示英文标题

标题： Revisiting string-inspired running-vacuum models under the lens of light primordial black holes

摘要： 轻度原初黑洞（PBHs）其质量为$M_\mathrm{PBH}<10^9\mathrm{g}$可以有趣地主导宇宙的能量预算，并在大爆炸核合成（BBN）之前产生早期物质主导（eMD）时期。 在此 eMD 时期，会大量产生诱导引力波（GWs），作为约束引力理论的基础。 在本工作中，我们研究了弦论启发的运行真空模型（StRVMs）背景下的这种类型的诱导 GWs，当在 de Sitter 背景附近展开时，这些模型包括时空曲率的对数修正。 特别是，我们详细讨论了 StRVMs 对这些 PBH 诱导 GWs 的源以及传播的影响。 值得注意的是，在假设对数项代表 PBH 时期的量子引力修正的前提下，如果我们假设这些对数修正的系数远大于约化普朗克质量的平方，则可以避免 GW 过度产生。 然而，后者无法表征量子引力修正，这促使需要在不同于 de Sitter 背景的情况下，如那些表征 PBH 驱动的 eMD 时期的背景中，对 StRVMs 的量子化进行修订。 这一非平凡的结果表明了轻度 PBH 作为新物理探测器的重要性。 显示英文摘要

摘要： Light primordial black holes (PBHs) with masses $M_\mathrm{PBH}<10^9\mathrm{g}$ can interestingly dominate the Universe's energy budget and give rise to early matter-dominated (eMD) eras before Big Bang Nucleosyntesis (BBN). During this eMD era, one is met with an abundant production of induced gravitational waves (GWs) serving as a portal to constrain the underlying theory of gravity. In this work, we study this type of induced GWs within the context of string-inspired running-vaccuum models (StRVMs), which, when expanded around de Sitter backgrounds, include logarithmic corrections of the space-time curvature. In particular, we discuss in detail the effects of StRVMs on the source as well as on the propagation of these PBH-induced GWs. Remarkably, under the assumption that the logarithmic terms represent quantum gravity corrections in the PBH era, we show that GW overproduction can be avoided if one assumes a coefficient of these logarithmic corrections that is much larger than the square of the reduced Planck mass. The latter cannot characterise quantum gravity corrections, though, prompting the need for revision of the quantisation of StRVMs in different than de Sitter backgrounds, such as those characterising PBH-driven eMD eras. This non trivial result suggests the importance of light PBHs as probes of new physics.