2019/06/17 by Antonia Micol Frassino, Antonia M. Frassino, Robert B. Mann +5
Physics and Astronomy · #Astrophysical Phenomena and Observations #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) #gr-qc #hep-th
paper · pdf · doi:10.48550/arxiv.1906.07190
30 pages, 12 figures -- final version to appear in JHEP
openalex publication_date 2019/06/17 · arxiv created 2019/11/06 · arxiv updated 2019/11/11 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We study several aspects of the extended thermodynamics of BTZ black holes with thermodynamic mass M=αm + γ(j)/(ℓ) and angular momentum J = αj + γℓ m, for general values of the parameters (α, γ) ranging from regular (α=1, γ=0) to exotic (α=0, γ=1). We show that there exist two distinct behaviours for the black holes, one when α> γ ("mostly regular"), and the other when γ< α ("mostly exotic"). We find that the Smarr formula holds for all (α, γ). We derive the corresponding thermodynamic volumes, which we find to be positive provided α and γ satisfy a certain constraint. The dependence of pressure on volume is unremarkable and strictly decreasing when α> γ, but a maximum volume emerges for large J≫ T when γ> α; consequently an exotic black hole of a given horizon circumference and temperature can exist in two distinct anti de Sitter backgrounds. We compute the reverse isoperimetric ratio, and study the Gibbs free energy and criticality conditions for each. Finally we investigate the complexity growth of these objects and find that they are all proportional to the complexity of the BTZ black hole. Somewhat surprisingly, purely exotic BTZ black holes have vanishing complexity growth.