General form of f(R) and (2 + 1)-dimensional charge/non-charge black hole solutions
Document Type
Article
Publication Date
2025
Abstract
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/different 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.
Recommended Citation
Nashed, Gamal, "General form of f(R) and (2 + 1)-dimensional charge/non-charge black hole solutions" (2025). Centre for Theoretical Physics and Computations. 340.
https://buescholar.bue.edu.eg/centre_theoretical_physics/340