Motivated by recent physical interpretation on quasinormal modes presented by Maggiore [Phys. Rev. Lett. 100, 141301 (2008)], the adiabatic quantity method given by Kunstatter [Phys. Rev. Lett. 90, 161301 (2003)] is used to calculate the spectrums of a non-extremal Schwarzschild de Sitter black hole in this paper, as well as electrically charged case. According to highly damped Konoplya and Zhidenko's numerical observational results for high overtone modes [JHEP 06, 037 (2004)], we found that the asymptotic non-flat spacetime structure leads to two interesting facts: (i) near inner event horizon, the area and entropy spectrums, which are given by Aen= 8 n1πℏ, Sen= 2πn1ℏ, are equally spaced accurately. (ii) However, near outer cosmological horizon the spectrums, which are in the form of [Formula: see text], are not markedly equidistant. Finally, we also discuss the electrically charged case and find that the black holes in de Sitter spacetime have similar quantization behavior no matter with or without charge.
Quasinormal modes of the near extremal Schwarzschild–de Sitter black hole