What the paper is about: The authors construct an exact family of spinning black hole solutions in five-dimensional general relativity with a negative cosmological constant. By the rules of holography — a proposed equivalence between gravity in higher dimensions and strongly coupled field theories on a lower-dimensional boundary — these black holes describe strongly coupled, rigidly rotating plasma “balls” living on ordinary four‑dimensional Minkowski spacetime. A surprising feature is that a boundary quantity (the local Lorentz factor of the rotating fluid) becomes a new bulk coordinate and opens a second ultraviolet region that is locally three‑dimensional de Sitter space times a line.

What the researchers did: Starting from five-dimensional Einstein gravity with a negative cosmological constant (anti–de Sitter or AdS asymptotics), the authors write down and analyze a new exact metric that depends on rotation and mass parameters. They show the solution matches a conformal boundary that is flat four‑dimensional spacetime and that the holographic energy–momentum tensor on that boundary takes the expected form of a conformal perfect fluid in rigid rotation with constant angular velocity. Concretely, they find the fluid pressure is set by an integration constant that enters the metric and falls off with the fourth power of the local Lorentz factor of the rotation, so the pressure becomes large near the radius where the local speed would reach the speed of light.

How the geometry works and what it predicts: The bulk spacetime has two distinct asymptotic regions. One is the usual AdS region used in holography. The other appears when the boundary Lorentz factor diverges; that second asymptotic region is locally three‑dimensional de Sitter space times a real line. The authors compute the energy–momentum tensor seen in this de Sitter region and find it represents an anisotropic conformal fluid that obeys standard energy conditions (the weak and strong energy conditions). The solution has a single event horizon for the chosen parameter range, with an explicit Hawking temperature formula and an infinite total horizon area so that one must work with an area density along the non‑compact directions.