New entropy formula for Kerr black holes

Abstract

Abstract. We introduce a new entropy formula for Kerr black holes inspired by recent results for 3-dimensional black holes and cosmologies with soft Heisenberg hair. We show that also Kerr-Taub-NUT black holes obey the same formula.

Warped symmetries of the Kerr black hole

“…Earlier related works by Carlip studying horizon symmetries for generic black holes exhibit the same ambiguity: depending on the choice of boundary conditions at the horizon, the symmetries can be either conformal [59][60][61][62] or BMS 3 [63], and both seem able to account for the black hole entropy. It is also worth mentioning that various proposals for boundary conditions at non-extremal horizons in three and four dimensions have appeared in recent years [41,[64][65][66][67][68][69][70][71][72]. The ambiguity in the choice of boundary conditions is reminiscent of the archetypical AdS 3 gravity setting: besides the Brown-Henneaux boundary conditions, a handful of alternative boundary conditions have appeared in recent years with symmetries differing from those of a pure CFT 2 [41,58,64,65,[73][74][75][76].…”

Black hole entropy and soft hair

“…Previous potentially related attempts to obtain 4D black hole entropy from a Virasoro action at the horizon include [19,42,[68][69][70][71][72][73][74].…”

Entropy formula in Einstein-Maxwell-dilaton theory and its validity for black strings

“…This may be seen as a problem but it is not, because, in Einstein-Maxwell-Dilaton theory, we have a U(1) gauge freedom and we use an appropriate gauge fixing to fix that problem. We show that new entropy formula 4πĴ + 0Ĵ − 0 , proposed in [5], is valid for black strings as well as black holes. * Electronic address: rezakord@ipm.ir † Electronic address: hamed.adami@yahoo.com…”

“…We have shown thatT (m,n) together with superrotation charge modes and multiple-charge modes satisfy the algebra (67). By introducing four new generatorsĴ ± m andK ± m so that they obey the algebra (68), one can apply the Sugawara deconstruction proposed in [5]. In this way, one can construct generatorsT (m,n) , Y (new) m andȲ (new) m as (69).…”