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

The longlived charged massive scalar field in the higher-dimensional Reissner--Nordstr\"{o}m spacetime

The quasinormal resonance frequency of the higher-dimensional Reissner--Nordstr\"{o}m (RN) black hole due to charged massive scalar field perturbation is deduced analytically in the eikonal regime. The characteristic decay timescale of the charged massive scalar perturbation in the background of the higher-dimensional RN spacetime is then obtained. The result reveals that longlived charged massive scalar field can exist in higher-dimensional RN spacetime under a certain condition.Comment: 6 pages, 1 figur