Boundary Value Problem for Black Rings
Yoshiyuki Morisawa, Shinya Tomizawa, Yukinori Yasui
TL;DR
This work addresses the uniqueness of asymptotically flat, stationary black rings in five-dimensional vacuum gravity under the presence of three commuting Killing vectors and S^1×S^2 horizon topology. It constructs a general four-parameter black ring solution (potentially with conical singularities) and identifies how demanding regularity removes these singularities to recover the Pomeransky-Sen'kov solution. The authors then apply the Mazur identity, within a boundary-value framework, to show that two solutions with the same mass, two angular momenta, and rod structure are isometric, thereby establishing uniqueness of the regular black ring in this class. The result narrows the landscape of possible higher-dimensional black holes by linking horizon topology, rod data, and asymptotic charges to a single regular solution, with implications for rigidity and higher-dimensional gravity.
Abstract
We study the boundary value problem for asymptotically flat stationary black ring solutions to the five-dimensional vacuum Einstein equations. Assuming the existence of two additional commuting axial Killing vector fields and the horizon topology of $S^1\times S^2$, we show that the only asymptotically flat black ring solution with a regular horizon is the Pomeransky-Sen'kov black ring solution.
