Extremal vanishing horizon Kerr-AdS black holes at ultraspinning limit

Abstract

By utilizing the ultraspinning limit we generate a new class of extremal vanishing horizon (EVH) black holes in odd dimensions (d ≥ 5). Starting from the general multi-spinning Kerr-AdS metrics, we show the EVH limit commutes with the ultraspinning limit,in which the resulting solutions possess a non-compact but finite area manifold for all (t, r ≠ r+) = const. slices. We also demonstrate the near horizon geometries of obtained ultraspinning EVH solutions contain an AdS3 throats, where it would be a BTZ black hole in the near EVH cases. The commutativity of the ultraspinning and near horizon limits for EVH solutions is confirmed as well. Furthermore, we discuss only five-dimensional case near the EVH point can be viewed as a super-entropic black hole. We also show that the thermodynamics of the obtained solutions agree with the BTZ black hole. Moreover we investigate the EVH/CFT proposal, demonstrating the entropy of 2d dual CFT and Bekenstein-Hawking entropy are equivalent.