Radial perturbations of the scalarized black holes in Einstein-Maxwell-conformally coupled scalar theory
De-Cheng Zou, Yun Soo Myung
Abstract
We perform the stability analysis for the scalarized charged black holes obtained from Einstein-Maxwell-conformally coupled scalar (EMCS) theory by employing the radial perturbations. The targeting black holes include a single branch of a scalarized charged black hole with the coupling parameter $\ensuremath{\alpha}>0$ inspired by the constant scalar hairy black hole as well as infinite branches of $n=0(\ensuremath{\alpha}\ensuremath{\ge}8.019),\phantom{\rule{0ex}{0ex}}1(\ensuremath{\alpha}\ensuremath{\ge}40.84),2(\ensuremath{\alpha}\ensuremath{\ge}99.89),\dots{}$ scalarized charged black holes found through the spontaneous scalarization on the Reissner-Nordstr\"om black hole. It turns out that the black hole in the single branch and the $n=0$ black hole are stable against radial perturbations, while the $n=1$, 2 excited black holes are unstable in the EMCS theory with both quadratic and exponential couplings.