Kinematic and energy properties of dynamical regular black holes

Abstract

Nonsingular black holes have received much attention in recent years as they provide an opportunity to avoid the singularities inherent to the mathematical black holes predicted by general relativity. Based on the assumption that semiclassical physics remains valid in the vicinity of their horizons, we derive kinematic properties of dynamically evolving spherically symmetric regular black holes. We review the Hawking--Ellis classification of their associated energy-momentum tensors and examine the status of the null energy condition in the vicinity of their horizons as well as their interior. In addition, we analyze the trajectory of a moving observer, find that the horizons can be crossed on an ingoing geodesic, and thus entering and exiting the supposedly trapped spacetime region is possible. We outline the ramifications of this result for the information loss problem and black hole thermodynamics. Throughout the article, we illustrate relevant features based on the dynamical generalization of the regular black hole model proposed in J. High Energy Phys. 09, 118 (2022) and elucidate connections to the only self-consistent dynamical physical black hole solutions in spherical symmetry.