Microscopic structures and thermal stability of black holes conformally coupled to scalar fields in five dimensions

Completely from the thermodynamic point of view, we explore the microscopic character of a hairy black hole of Einstein's theory conformally coupled to a scalar field in five dimensions by means of the Ruppeiner thermodynamic geometry. We demonstrate that the scalar hairy black hole has rich microscopic structures in different parameter spaces. Moreover, we analyze the thermal stability of this black hole in detail.Comment: v1: 15 pages, 1 figure; v2: 19 pages, clarifications and references added; v3: clarifications and references added; v4: 21 pages, clarifications added; v5: minor clarifications and one reference added, final version to appear in Nuclear Physics

Hawking Radiation of Five-dimensional Charged Black Holes with Scalar Fields

We investigate the Hawking radiation cascade from the five-dimensional charged black hole with a scalar field coupled to higher-order Euler densities in a conformally invariant manner. We give the semi-analytic calculation of greybody factors for the Hawking radiation. Our analysis shows that the Hawking radiation cascade from this five-dimensional black hole is extremely sparse. The charge enhances the sparsity of the Hawking radiation, while the conformally coupled scalar field reduces this sparsity.Comment: v1: 11 pages, 2 figures, 2 tables; v2: 12 pages, references and clarifications added, final version to appear in Phys. Lett.