Nonlinear Magnetically Charged Black Holes with Phantom Global Monopoles: Thermodynamics, Geodesics, Quasinormal Modes, and Grey-Body Factors
B. Hamil, B. C. Lütfüoğlu
TL;DR
Addressing black holes in the presence of nonlinear electrodynamics and phantom global monopoles, this work constructs an exact static solution and examines its geometric, thermodynamic, and perturbative properties. It analyzes thermodynamics (temperature, entropy, phase structure), geodesics (ISCO and Lyapunov), quasinormal modes (WKB and PT), and grey-body factors, showing observable deviations from GR in strong-field regimes. Through sixth-order WKB and Pöschl–Teller approximations, the study reveals signatures of the phantom monopole and NLE in the QNM spectrum and radiation, with possible observational consequences for black hole shadows and gravitational waves. The results motivate extensions to rotating and higher-dimensional setups to further probe exotic-field effects with astrophysical data.
Abstract
We study the properties of a nonlinear magnetic-charged black hole in the presence of a phantom global monopole. By incorporating nonlinear electrodynamics (NLE) and exotic scalar fields, we derive an exact black hole solution and analyze its geometric structure, causal properties, and thermodynamic behavior. We examine how the presence of a phantom global monopole modifies the black hole's Hawking temperature, entropy, and stability conditions, revealing significant changes in its phase structure. Additionally, we investigate the geodesic motion of test particles. The quasinormal mode (QNM) spectrum is computed using the WKB approximation and Pöschl-Teller potential method, providing insights into the perturbative stability of the system. Furthermore, we analyze the grey-body factors that characterize radiation emission, highlighting their dependence on black hole parameters. Our findings indicate that the interplay between phantom energy, NLE, and global monopoles introduces observable deviations in strong-field astrophysical phenomena. These results offer potential signatures for testing modified gravity theories and contribute to a deeper understanding of black hole physics in exotic field environments.