The detection of gravitational waves from mergers of tens of Solar mass black hole binaries has led to a surge in interest in primordial black holes (PBHs) as a dark matter candidate. We aim to provide a (relatively) concise overview of the status of PBHs as a dark matter candidate, circa Summer 2020. First we review the formation of PBHs in the early Universe, focussing mainly on PBHs formed via the collapse of large density perturbations generated by inflation. Then we review the various current and future constraints on the present day abundance of PBHs. We conclude with a discussion of the key open questions in this field.

中文翻译：

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原始黑洞作为暗物质候选者

数十个太阳质量黑洞双星的合并检测到了引力波，导致人们对作为暗物质候选者的原始黑洞（PBHs）的兴趣激增。我们旨在（相对）简明扼要地概述PBH作为暗物质候选物的状态，大约在2020年夏季。首先，我们回顾一下早期宇宙中PBH的形成，主要关注由大密度扰动的崩塌形成的PBH。通过通货膨胀。然后，我们回顾了当前和将来PBHs丰度的各种限制。最后，我们讨论了该领域的主要开放性问题。