2025/09/18 by G. G. L. Nashed, Nashed, G. G. L.
Physics and Astronomy · #Black Holes and Theoretical Physics #Cosmology and Gravitation Theories #FOS: Physical sciences #General Relativity and Quantum Cosmology (gr-qc) #High Energy Physics - Theory (hep-th)
paper · pdf · doi:10.48550/arxiv.2509.15282
openalex publication_date 2025/09/18 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We introduce novel black hole (BH) solutions, charge/non-charge, within the framework of f(R) gravity, a theory that does not inherently include a cosmological constant, using equal/diffirent metric ansatzs. Remarkably, these solutions exhibit asymptotically Anti-de Sitter (AdS) or de Sitter (dS) behavior, depending on their parameter values. Unlike the BTZ solutions of General Relativity, which feature a causal singularity and constant scalar invariants, our solutions display strong spacetime singularities, as shown by their scalar invariants. We construct f(R) functions that behave as polynomial functions, emphasizing the unique nature of these solutions. We demonstrate the stability of these solutions in two ways: first, by showing that their heat capacity is positive, which ensures thermodynamic stability; and second, by proving that the second derivative of f(R) is positive, meeting the Ostrogradski criterion for dynamical stability. Furthermore, the solutions satisfy the first law of thermodynamics, confirming their consistency with fundamental thermodynamic principles.