Bernstein spectral method for quasinormal modes of a generic black hole spacetime and application to instability of dilaton-de Sitter solution

R. A. Konoplya and A. Zhidenko

Submitted on 5 November 2022, last revised on 14 November 2022


We present the improved Mathematica code which computes quasinormal frequencies with the help of the Bernstein spectral method for a general class of black holes, allowing for asymptotically flat, de Sitter or anti-de Sitter asymptotic. The method is especially efficient when searching for purely imaginary modes and here it is used for detecting the instability region of a charged scalar field in the background of the charged asymptotically de Sitter dilatonic black hole. We show that the instability has superradiant nature and the dilaton field essentially influences the region of instability.


Comment: 8 pages, 2 figures, 2 ancillary files

Subjects: General Relativity and Quantum Cosmology; Astrophysics - High Energy Astrophysical Phenomena; High Energy Physics - Theory


The effective potential $V(r)$ for $\ell=0$ case, $\Lambda = 0.03$: $D =0$ (blue, lower), $D=0.25$ (red) and $D=0.45$ (green, upper).