Concentric Black Rings

TL;DR

The paper develops new supersymmetric solutions in five-dimensional minimal supergravity describing concentric black rings, optionally centered on a black hole, by exploiting a Gibbons-Hawking base and harmonic functions $K,L,M$ to linearize multi-ring constructions. It demonstrates that multiple rings can share the same charges as a known rotating black hole and that their horizon areas can be tuned relative to the black hole, with preliminary numerical evidence indicating the absence of closed timelike curves. It also interprets these configurations geometrically in $\mathbb{R}^4$, analyzes special cases with poles on the $z$-axis, and explores the infinite-radius limit leading to multi-black-string solutions, outlining future directions for entropy counting and broader generalisations. Overall, the work extends the landscape of fully supersymmetric multi-centered black object solutions and highlights intriguing physical properties arising from ring convergence and central holes.

Abstract

We present new supersymmetric solutions of five-dimensional minimal supergravity that describe concentric black rings with an optional black hole at the common centre. Configurations of two black rings are found which have the same conserved charges as a single rotating black hole; these black rings can have a total horizon area less than, equal to, or greater than the black hole with the same charges. A numerical investigation of these particular black ring solutions suggests that they do not have closed timelike curves.