Black diring and infinite nonuniqueness
Hideo Iguchi, Takashi Mishima
TL;DR
The paper investigates five-dimensional vacuum gravity with $S^1$-rotating black rings and demonstrates that concentric di-ring configurations can be generated via a solution-generating technique based on the Weyl-Papapetrou formalism and rod-structure analysis. By applying a solitonic transformation to a carefully chosen seed, the authors construct the black di-ring, fix regularity and periodicity conditions to eliminate conical singularities, and extract physical quantities from the asymptotic Ernst potential. A key result is the existence of infinite nonuniqueness: there are continuous families of di-rings with the same mass $m$ and angular momentum $J$, including a path that connects the fat and thin single black rings. The work highlights di-rings as a mechanism to explore the landscape of 5D black objects and suggests further extensions to multi-angular-momentum solutions and connections to configurations like black Saturn.
Abstract
We show that the $S^1$-rotating black rings can be superposed by the solution generating technique. We analyze the black diring solution for the simplest case of multiple rings. There exists an equilibrium black diring where the conical singularities are cured by the suitable choice of physical parameters. Also there are infinite numbers of black dirings with the same mass and angular momentum. These dirings can have two different continuous limits of single black rings. Therefore we can transform the fat black ring to the thin ring with the same mass and angular momentum by way of the diring solutions.
