Pair creation in non-extremal fuzzball geometries
Borun D. Chowdhury, Samir D. Mathur
TL;DR
This work analyzes a concrete, nonextremal fuzzball family as a horizonless microstate geometry for the D1‑D5 system. By solving the minimally coupled scalar wave equation via inner $AdS_3\times S^3$ and outer flat regions and performing an in‑region/out‑region matching, it identifies an ergoregion‑driven instability whose emitted quanta split into infinity‑going radiation and interior ergoregion excitations, with equal and opposite energy and angular momentum. The gravity result reproduces the Hawking emission for this specific microstate when compared with the dual CFT, and the exponential growth is explained by Bose enhancement unique to the microstate’s coherent component strings. The paper then argues that generic nonextremal microstates, which lack axial symmetry, will contain ergoregions and produce Hawking‑like radiation, while the details depend on ergoregion depth and backreaction, offering a path to resolving information‑paradox issues without horizons.
Abstract
It is possible to construct a special family of nonextremal black hole microstates. These microstates are unstable, and emit radiation at a rate which is found to exactly equal the Hawking radiation rate predicted for them by the dual CFT. In this paper we analyze in more detail the nature of the radiation created by these unstable modes. The energy and angular momentum of the mode is found to be localized in two regions: one near infinity corresponding to the emitted quanta, and the other in the ergoregion which is deep inside the interior of the geometry. The energy and angular momenta are equal and opposite for these two contributions, as expected for emission from ergoregions. We conjecture that more general nonextremal microstates will possess ergoregions (with no axial symmetry), and radiation from these regions can be part of the general Hawking emission for the microstates.