Ultra-spinning gauged supergravity black holes and their Kerr/CFT correspondence

Abstract

Recently a new class of asymptotically AdS ultra-spinning black holes has been constructed with a noncompact horizon of finite area [1], in which the asymptotic rotation is effectively boosted to the speed of light. We employ this technique for four-dimensional U (1) 4 and five-dimensional U (1) 3 gauged supergravity black holes. The obtained new exact black hole solutions for both cases possess a noncompact horizon; their topologies are a sphere with two punctures. We then demonstrate that the ultra-spinning limit commutes with the extremality condition as well as the near horizon limit for both black holes. We also show that the near horizon extremal geometries of the resulting ultra-spinning gauged supergravity black holes lead to the well-known result which contains an AdS 2 throat. We then obtain the [(d − 1)/2] central charges of the dual CFTs. By assuming the Cardy formula, we show that despite the noncompactness of the horizon, microscopic entropy of the dual CFT is precisely equivalent to the Bekenstein-Hawking entropy.1

Extremal vanishing horizon Kerr-AdS black holes at ultraspinning limit

“…This idea has been fully studied for large families of black holes [21], indicating the microscopic entropy of the dual CFT via the Cardy formula exactly agree with the Bekenstein-Hawking entropy of the extreme kerr black hole. Also the validity of this correspondence has been confirmed for ultraspinning non-compactness horizon black holes in [14,15,47].…”

“…While in other dimensions we cannot find EVH super-entropic black holes. We expect that the EVH limit of recently obtained charged ultraspinning black holes in diverse dimensions [14,15] can be established through an analogous strategy that we have presented.…”

“…It was shown that for a large class of extremal black holes the near horizon and ultraspinning limits commute with each other [14,15,47]. Now, we explore whether the near horizon limit of an EVH solution commute with the ultraspinning limit.…”

“…This novel ultraspinning limit can be viewed as a simple generating black hole solution technique in the presence of the cosmological constant. Several authors have applied this method to construct new black hole solutions from multi-spinning Kerr-AdS black holes (KAdS) [13], four and five-dimensional gauged supergravity solutions [14] and higher dimensional charged AdS black holes [15]. In all cases, the resulting new exact black hole possess a non-compact horizon with finite entropy, that topologically describes a sphere with some punctures.…”

Thermodynamic instabilities of generalized exotic BTZ black holes

“…When the equality is saturated, a black hole of a given thermodynamic volues has attained its maximal possible entropy. Since then, the isoperimetric ratio R of various black hole families have been studied, and some were found to violate this inequality [8][9][10][11][12][13][14][15][16]. Such black holes have come to be called super-entropic, since they have more entropy that the relation (1) would admit.…”