Black rings in global anti-de Sitter space

Understand

We construct five dimensional black rings in global anti-de Sitter space using numerical methods.

• These rings satisfy the BPS bound $| J | < M \ell$, but the angular velocity always violates the Hawking-Reall bound $| \Omega_H \ell | \leq 1$, indicating that they should be unstable under superradiance.
• At high temperatures, the limit $| \Omega_H \ell | \searrow 1$ is attained by thin rings with an arbitrarily large radius.
• However, at sufficiently low temperatures, this limit is saturated by a new kind of rings, whose outer circle can still be arbitrarily long while the hole in the middle does not grow proportionally.