Kerr-Newman Black Hole Entropy and Soft Hair

Understand

Recently a set of diffeomorphisms were found which act nontrivially on the Kerr horizon and form a left-right pair of Virasoro algebras.

• Using the boundary formula for the associated central charge and assuming applicability of the Cardy formula to a putative dual CFT, the Bekenstein-Hawking entropy for the Kerr black hole was reproduced.
• In this paper, the addition of charge to the black hole is shown to require a minimal modification to this construction which then reproduces the Bekenstein-Hawking entropy for the Kerr-Newman black hole.