Black Hole Horizon Fluffs: Near Horizon Soft Hairs as Microstates of Three Dimensional Black Holes

TL;DR

This paper proposes a novel class of black hole microstates called 'horizon fluffs' in three dimensions, which are near horizon soft hairs with zero energy, accounting for black hole entropy through conformal algebra and partition counting.

Contribution

It introduces the explicit construction of all microstates for 3D black holes as horizon fluffs, linking near horizon soft hairs to microstates and entropy calculation.

Findings

Microstates are organized in conformal orbits.

Entropy matches Bekenstein-Hawking formula.

Potential extension to Kerr black holes.

Abstract

We provide the first explicit proposal for all microstates of generic black holes in three dimensions (of Banados-Teitelboim-Zanelli-type): black hole microstates, termed "horizon fluffs", are a particular class of near horizon soft hairs which have zero energy as measured by the horizon observer and cannot be distinguished by observers at finite distance from the horizon. These states are arranged in orbits of the two-dimensional conformal algebra associated with the asymptotic black hole geometry. We count these microstates using the Hardy-Ramanujan formula for the number of partitions of a given integer into non-negative integers, recovering the Bekenstein-Hawking entropy. We discuss possible extensions of our black hole microstate construction to astrophysical Kerr-type black holes.