Speaker
Description
When primordial black holes (PBHs) form in the early universe, their environment is dominated by the radiation bath and the not-very-distant cosmological horizon. There are a wide number of cosmological black hole' metrics which describe such objects---locally black-hole like objects which are asymptotically FLRW. However, pretty much all of these metrics have various flaws, such as physical singularities or pressure conditions which require matter-dominated backgrounds. I will briefly discuss some of these solutions, and the formalism we use to study them more clearly. I will also argue that the choice of such metric may have large phenomenological consequences, specifically regarding PBHs as a dark matter candidate. It is not easy to find an entirely convincing candidate, but I will use a somewhat generic framework and onetoy' metric---the Thakurta metric---to demonstrate how the constraints on PBH dark matter might depend heavily on the early-universe cosmological black hole metric. Based partly on: https://arxiv.org/abs/2008.10743, https://arxiv.org/abs/2103.02815, https://arxiv.org/abs/2112.13921.
