Black Hole Giants

TL;DR

The authors tackle microstate counting for the simplest $1/16$-BPS AdS$_5$ black hole by quantizing near-horizon dual giant configurations and comparing to the macroscopic entropy $S_{BH}$. They identify an apparent missing degeneracy, attributed to an angular-momentum quantum number arising from world-volume electromagnetic waves on D3-branes, and show how fluxes can supply this quantum number while preserving the same near-horizon SUSY. A detailed analysis of world-volume fluxes on $1/8$-BPS dual giants in AdS$_5\times S^5$ reveals that flux-carrying configurations yield $1/16$-BPS states with an additional angular momentum, suggesting a path to reconcile microscopic counts with $S_{BH}$. The work connects near-horizon brane dynamics, $
$-κ symmetry, and fuzzball concepts, laying groundwork for a fuller partition-function treatment of the black hole microstates.

Abstract

We investigate giant and dual giant type BPS configurations in the near-horizon geometry of a certain 1/16-BPS AdS_5 black hole. By quantising the space of solutions we count the dual giant configurations and compare with the black hole entropy. This suggests a missing degeneracy factor which we argue comes from an angular momentum quantum number. From the D-brane world volume this arises from BPS electromagnetic waves. We study these waves in the context of giants and dual giants in the black hole near-horizon geometry. We further demonstrate that turning on waves on the world-volume of 1/8-BPS dual giants in AdS_5 x S^5 leads to 1/16-BPS states with an additional angular momentum quantum number.