Charged Nariai black holes on the dark bubble

Abstract

In this paper, we realise the charged Nariai black hole on a braneworld from a
nucleated bubble in AdS5, known as the dark bubble model. Geometrically, the black hole
takes the form of a cylindrical spacetime pulling on the dark bubble. This is realised by a
brane embedding in an AdS5 black string background. Identifying the brane with a D3-brane
in string theory allows us to determine a relation between the fine structure constant and the
string coupling, αEM = 3 gs/2, which was previously obtained for a microscopic black hole. We
also speculate on the consequences for the Festina Lente bound and neutrino masses.