Late time decay of scalar and Dirac fields around an asymptotically de Sitter black hole in the Euler-Heisenberg electrodynamics

Abstract: We compute the quasinormal modes of massive scalar and Dirac fields within the framework of asymptotically de Sitter black holes in Euler-Heisenberg non-linear electrodynamics. We pay particular attention to the regime $\mu M/m_{P}^2 \gg 1$, where $\mu$ and $M$ denote the masses of the field and the black hole, respectively, and $m_{P}$ represents the Planck mass, covering a range from primordial to large astrophysical black holes. Through time-domain integration, we demonstrate that, contrary to the asymptotically flat case, the quasinormal modes also dictate the asymptotic decay of fields. Employing the 6th order WKB formula, we derive a precise analytic approximation for quasinormal modes in the regime $\mu M/m_{P}^2 \gg 1$ without resorting to expansion in terms of the inverse multipole number. This analytic expression takes on a concise form in the limit of linear electrodynamics, represented by the Reissner-Nordstr\"om black holes.