2017/03/31 by Gianluca Calcagni, David Rodríguez Fernández, Michele Ronco
Physics and Astronomy · #Black Holes and Theoretical Physics #Black hole (networking) #Cosmology and Gravitation Theories #General relativity #Hawking radiation #Micro black hole #Noncommutative and Quantum Gravity Theories #RADIUS #Schwarzschild radius #Spacetime #Unimodular matrix #gr-qc #hep-th
paper · pdf · doi:10.1140/epjc/s10052-017-4879-5
published as Eur. Phys. J. C 77, 335 (2017) · 17 pages, 3 figures. v2: minor typos corrected, references added
openalex created_date 2017/04/07 · openalex publication_date 2017/05/01 · arxiv created 2017/05/25 · arxiv updated 2017/05/26 · openalex updated_date 2026/08/05
We study static and radially symmetric black holes in the multi-fractional theories of gravity with q-derivatives and with weighted derivatives, frameworks where the spacetime dimension varies with the probed scale and geometry is characterized by at least one fundamental length ℓ _* ℓ ∗ . In the q-derivatives scenario, one finds a tiny shift of the event horizon. Schwarzschild black holes can present an additional ring singularity, not present in general relativity, whose radius is proportional to ℓ _* ℓ ∗ . In the multi-fractional theory with weighted derivatives, there is no such deformation, but non-trivial geometric features generate a cosmological-constant term, leading to a de Sitter–Schwarzschild black hole. For both scenarios, we compute the Hawking temperature and comment on the resulting black-hole thermodynamics. In the case with q-derivatives, black holes can be hotter than usual and possess an additional ring singularity, while in the case with weighted derivatives they have a de Sitter hair of purely geometric origin, which may lead to a solution of the cosmological constant problem similar to that in unimodular gravity. Finally, we compare our findings with other Lorentz-violating models.