New Topological Gauss-Bonnet Black Holes in Five Dimensions

We investigate vacuum static black hole solutions of Einstein-Gauss-Bonnet gravity with a negative cosmological constant in five dimensions. These are solutions with horizons of nontrivial topologies. The first one possesses a horizon with the topology $S^1 \times H^2$, and a varying Gauss-Bonnet coupling constant $\alpha$. By looking into its thermodynamic properties, we find that its specific heat capacity with fixed volume is negative, therefore it is thermodynamically unstable. The second one is equipped with a so-called "Sol-manifold" as its horizon, and interestingly, the product of the Gauss-Bonnet coupling constant $\alpha$ and the cosmological constant $\Lambda$ is fixed. For the second solution, the total energy and entropy vanish. These results enlarge our knowledge of both topological black holes in higher dimensions and the property of higher curvature corrections of gravitational theories.