Dilatonic interpolation between Reissner–Nordström and Bertotti–Robinson spacetimes with physical consequences

Abstract

We give a general class of static, spherically symmetric, non-asymptotically flat and asymptotically non-(anti) de Sitter black hole solutions in Einstein–Maxwell–Dilaton (EMD) theory of gravity in four dimensions. In this general study we couple a magnetic Maxwell field with a general dilaton potential, while double Liouville-type potentials are coupled with gravity. We show that the dilatonic parameters play a key role in switching between the Bertotti–Robinson and Reissner–Nordström spacetimes. We study the stability of such black holes under a linear radial perturbation, and in this sense we find exceptional cases where the EMD black holes are unstable. In continuation, we give a detailed study of the spin-weighted harmonics in the dilatonic Hawking radiation spectrum and compare our results with previously known ones. Finally, we investigate the status of resulting naked singularities of our general solution when probed with quantum test particles.