Resolving Black-Hole Microstructure with New Momentum Carriers

TL;DR

This paper constructs new horizonless microstate geometries with spherical symmetry and zero horizon area, where momentum is carried by internal D0-D4 fluctuations, challenging the notion that finite horizons are necessary for black-hole microstates.

Contribution

It introduces solutions with zero horizon area that preserve spherical symmetry and carry momentum via internal brane fluctuations, expanding the understanding of black-hole microstate geometries.

Findings

Solutions have zero horizon area and spherical symmetry.

Momentum is carried by D0-D4 density fluctuations inside NS5-branes.

These geometries suggest horizons are not necessary even in complex microstate spaces.

Abstract

All known horizonless black-hole microstate geometries correspond to brane sources that acquire a finite size, and hence break the spherical symmetry of the black hole. We construct, for the first time, solutions with zero horizon area that have the same charges as a three-charge F1-NS5-P Type-IIA black hole and preserve this spherical symmetry. The momentum of these solutions is carried by longitudinal D0-D4 density fluctuations inside the NS5-branes. We argue that these solutions should be interpreted as the long-throat limit of a family of smooth, horizonless microstate geometries, called superstrata, where such geometries degenerate. The existence of these geometries indicates that a finite-size horizon does not appear even in the singular corners of the moduli space of three-charge microstate geometries.