Instability of small AdS black holes in sixth-order gravity

We investigate the stability analysis of AdS black holes in the higher dimensional sixth-order gravity. This gravity is composed of Ricci cubic gravity and Lee-Wick term. It indicates that the Ricci tensor perturbations exhibit unstable modes for small AdS black holes in Ricci cubic gravity by solving the Lichnerowicz-type linearized equation. We show that the correlated stability conjecture holds for the AdS black hole by computing all thermodynamic quantities in Ricci cubic gravity. Furthermore, we find a newly non-AdS black hole in Ricci cubic gravity by making use of a static eigenfunction of the Lichnerowicz operator.Comment: 27 pages, 4 figures. arXiv admin note: text overlap with arXiv:1801.0462

Instability of Reissner-Nordstr\"{o}m black hole in Einstein-Maxwell-scalar theory

The scalarization of Reissner-Nordstr\"{o}m black holes was recently proposed in the Einstein-Maxwell-scalar theory. Here, we show that the appearance of the scalarized Reissner-Nordstr\"{o}m black hole is closely related to the Gregory-Laflamme instability of the Reissner-Nordstr\"{o}m black hole without scalar hair.Comment: 22 pages, 10 figures, version to appear in EPJ

Stability of scalarized charged black holes in the Einstein-Maxwell-Scalar theory

We analyze the stability of scalarized charged black holes in the Einstein-Maxwell-Scalar (EMS) theory with quadratic coupling. These black holes are labelled by the number of $n=0,1,2,\cdots$, where $n=0$ is called the fundamental black hole and $n=1,2,\cdots$ denote the $n$-excited black holes. We show that the $n=0$ black hole is stable against full perturbations, whereas the $n=1,2$ excited black holes are unstable against the $s(l=0)$-mode scalar perturbation. This is consistent with the EMS theory with exponential coupling, but it contrasts to the $n=0$ scalarized black hole in the Einstein-Gauss-Bonnet-Scalar theory with quadratic coupling. This implies that the endpoint of unstable Reissner-Nordstr\"{o}m black holes with $\alpha>8.019$ is the $n=0$ black hole with the same $q$. Furthermore, we study the scalarized charged black holes in the EMS theory with scalar mass $m^2_\phi=\alpha/\beta$.Comment: 23 pages, 11 figures. arXiv admin note: text overlap with arXiv:1812.0360

Reentrant phase transitions of higher-dimensional AdS black holes in dRGT massive gravity

We study the $P-V$ criticality and phase transition in the extended phase space of anti-de Sitter (AdS) black holes in higher-dimensional de Rham, Gabadadze and Tolley (dRGT) massive gravity, treating the cosmological constant as pressure and the corresponding conjugate quantity is interpreted as thermodynamic volume. Besides the usual small/large black hole phase transitions, the interesting thermodynamic phenomena of reentrant phase transitions (RPTs) are observed for black holes in all $d\geq6$-dimensional spacetime when the coupling coefficients $c_i m^2$ of massive potential satisfy some certain conditions.Comment: 14 pages, several references are added, v2: published in EPJ