2020/10/31 by G. G. L. Nashed, Emmanuel N. Saridakis · 54 citations
Mathematics · Physics and Astronomy · #Black Holes and Theoretical Physics #Black hole (networking) #Classical mechanics #Computer science #Cosmology and Gravitation Theories #Entropy (arrow of time) #General relativity #Geometry #Gravitation #Gravitational field #Gravitational singularity #Mathematical physics #Mathematics #Naked singularity #Physics #Pulsars and Gravitational Waves Research #Quantum mechanics #Singularity #gr-qc #hep-th
paper · pdf · doi:10.1103/physrevd.102.124072
published in Physical review. D/Physical review. D. 102(12) (American Physical Society) · 10 pages, 6 figures, version published in Phys.Rev.D
openalex created_date 2020/10/29 · arxiv created 2020/12/29 · openalex publication_date 2020/12/29 · arxiv updated 2021/01/04 · openalex updated_date 2026/08/05
We investigate static and rotating charged spherically symmetric solutions in the framework of f(R) gravity, allowing additionally the electromagnetic sector to depart from linearity. Applying a convenient, dual description for the electromagnetic Lagrangian, and using as an example the square-root f(R) correction, we solve analytically the involved field equations. The obtained solutions belong to two branches, one that contains the Kerr-Newman solution of general relativity as a particular limit, and one that arises purely from the gravitational modification with no general relativity limit. The novel black hole solution has a true central singularity which is hidden behind a horizon; however, for particular parameter regions the horizon disappears and the singularity becomes a naked one. Furthermore, we investigate the thermodynamical properties of the solutions, such as the temperature, energy, entropy, heat capacity, and Gibbs free energy. We extract the entropy and quasilocal energy positivity conditions, we show that negative-temperature, ultracold, black holes are possible, and we show that the obtained solutions are thermodynamically stable for suitable model parameter regions.