There is controversy surrounding the origin and evolution of our universe's largest supermassive black holes (SMBHs). In this study, we consider the possibility that some of these black holes formed from the direct collapse of primordial density perturbations. Since the mass of a primordial black hole is limited by the size of the cosmological horizon at the time of collapse, these SMBHs must form rather late, and are naively in conflict with constraints from CMB spectral distortions. These limits can be avoided, however, if the distribution of primordial curvature perturbations is highly non-Gaussian. After quantifying the departure from Gaussianity needed to evade these bounds, we explore a model of multi-field inflation — a non-minimal, self-interacting curvaton model — which has all the necessary ingredients to yield such dramatic non-Gaussianities. We leave the detailed model building and numerics to a future study, however, as our goal is to highlight the challenges associated with forming SMBHs from direct collapse and to identify features that a successful model would need to have. This study is particularly timely in light of recent observations of high-redshift massive galaxy candidates by the James Webb Space Telescope as well as evidence from the NANOGrav experiment for a stochastic gravitational wave background consistent with SMBH mergers.

中文翻译：

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暴胀造成的超大质量原初黑洞

关于宇宙中最大的超大质量黑洞（SMBH）的起源和演化存在争议。在这项研究中，我们考虑了其中一些黑洞是由原初密度扰动的直接塌缩形成的可能性。由于原始黑洞的质量受到坍缩时宇宙视界大小的限制，因此这些超大质量黑洞必须形成得相当晚，并且与宇宙微波背景光谱畸变的限制相冲突。然而，如果原初曲率扰动的分布是高度非高斯的，那么这些限制是可以避免的。在量化了逃避这些界限所需的高斯性偏离之后，我们探索了一种多场膨胀模型——一种非最小的、自相互作用的曲线模型——它拥有产生如此戏剧性的非高斯性的所有必要成分。然而，我们将详细的模型构建和数值留待将来的研究，因为我们的目标是强调与直接坍塌形成超大黑洞相关的挑战，并确定成功模型需要具备的特征。鉴于詹姆斯·韦伯太空望远镜最近对高红移大质量星系候选体的观测，以及 NANOGrav 实验提供的与 SMBH 合并一致的随机引力波背景的证据，这项研究显得尤为及时。