G. I. Róis, J. T. S. S. Junior, F. S. N. Lobo, M. E. Rodrigues
Abstract
This work conducts an in-depth exploration of exact electrically charged solutions, including traversable wormholes, black holes, and black bounces, within the framework of the scalar-tensor representation of hybrid metric-Palatini gravity (HMPG) with a non-zero scalar potential. By integrating principles from both the metric and Palatini formulations, HMPG provides a flexible approach to addressing persistent challenges in General Relativity (GR), such as the late-time cosmic acceleration and the nature of dark matter. Under the assumption of spherical symmetry, we employ an inverse problem technique to derive exact solutions in both the Jordan and Einstein conformal frames. This method naturally leads to configurations involving either canonical or phantom scalar fields. A thorough examination of horizon structures, throat conditions, asymptotic behaviour, and curvature regularity (via the Kretschmann scalar) reveals the intricate causal structures permitted by this theoretical model. The analysis uncovers a diverse range of geometric configurations, with the phantom sector exhibiting a notably richer spectrum of solutions than the canonical case. These solutions encompass traversable wormholes, black bounces, where the interior of a black hole evolves into an expanding cosmological phase rather than a singularity, as well as multi-horizon black holes. The results demonstrate that introducing a non-zero scalar potential within HMPG significantly expands the array of possible gravitational solutions, yielding complex causal and curvature properties that go beyond standard GR. Consequently, HMPG stands out as a powerful theoretical framework for modelling extreme astrophysical environments, where deviations from classical gravity are expected to play a crucial role. Future research will focus on evaluating the stability of these solutions and investigating potential observational signatures, such as gravitational lensing effects and gravitational wave emissions.
Keywords
Exact solutions / black holes and black hole thermodynamics in GR and beyond / gravity / modified gravity / GR black holes / General Relativity and Quantum Cosmology / High Energy Astrophysical Phenomena / High Energy Physics - Theory
Journal of Cosmology and Astroparticle Physics
Volume 2025, Issue 078, Page 59
2025 July
