Dynamical and Semiclassical Properties of Regular Black Holes in Quasitopological Gravity
This dissertation investigates the physical properties of higher-dimensional regular black holes arising from the recently proposed infinite tower of higher-curvature corrections to General Relativity. These theories generate singularity-free black-hole solutions while preserving event horizons and a consistent semiclassical description.
Using analytical and numerical methods, we study scalar and electromagnetic perturbations and compute the corresponding quasinormal modes, greybody factors, absorption cross sections, and Hawking radiation spectra. We find that higher-curvature corrections systematically reduce both the oscillation frequencies and damping rates of the quasinormal modes relative to their general relativistic counterparts. In addition, the effective scattering barrier becomes higher and broader, leading to a suppression of transmission probabilities and a substantial reduction of the Hawking emission rates.
The optical properties of the solutions are also modified. Regularization increases the photon capture region, resulting in larger shadow radii and absorption cross sections. Furthermore, the suppression of Hawking radiation becomes increasingly pronounced as the extremal regime is approached, suggesting an asymptotic evolution toward a zero-temperature remnant configuration.
These results indicate that higher-curvature regularization leaves distinctive signatures in the dynamical, radiative, and optical properties of black holes, providing potential observational probes of regular geometries beyond General Relativity.