Microscopics of Extremal Kerr from Spinning M5 Branes

TL;DR

The paper develops a microscopic description of the four-dimensional extremal Kerr black hole by studying the spinning magnetic M5-brane in five-dimensional minimal supergravity and its decoupled near-horizon limit. It constructs an interpolating geometry that connects the AdS3×S^2 null orbifold (DLCQ of the MSW CFT) to the near-horizon Kerr×S^1 region, identifying the dual field theory as a deformation of the MSW CFT (DMSW) at small angular momentum. The authors compute operator deformations and show that the deformed theory preserves a Kerr-CFT-like Virasoro structure along the z-circle with a central charge c∼6R^3, suggesting DMSW as the microscopic definition of the Kerr-CFT in the small-Jφ regime. They further argue for a finite-deformation extension, proposing a family of Virasoro algebras with central charge c_u=6R^3 and connecting various Kerr-CFT descriptions across limits, thereby outlining a path to a unified microscopic picture of extremal Kerr from spinning M5-branes.

Abstract

We show that the spinning magnetic one-brane in minimal five-dimensional supergravity admits a decoupling limit that interpolates smoothly between a self-dual null orbifold of AdS_3 \times S^2 and the near-horizon limit of the extremal Kerr black hole times a circle. We use this interpolating solution to understand the field theory dual to spinning M5 branes as a deformation of the Discrete Light Cone Quantized (DLCQ) Maldacena-Stominger-Witten (MSW) CFT. In particular, the conformal weights of the operators dual to the deformation around AdS_3 \times S^2 are calculated. We present pieces of evidence showing that a CFT dual to the four-dimensional extremal Kerr can be obtained from the deformed MSW CFT.