2020/04/14 by Shahar Hod
Mathematics · Physics and Astronomy · #Astrophysical Phenomena and Observations #Black Holes and Theoretical Physics #Black hole (networking) #Bounded function #Combinatorics #Conjecture #Cosmology and Gravitation Theories #Function (biology) #General relativity #Geodesic #Geometry #Horizon #Mathematical analysis #Mathematical physics #Mathematics #Monotonic function #Null (SQL) #Physics #RADIUS #astro-ph.HE #gr-qc #hep-th
paper · pdf · doi:10.1103/physrevd.101.084033
published as Physical Review D 101, 084033 (2020) · 8 pages
openalex publication_date 2020/04/14 · arxiv created 2020/12/07 · arxiv updated 2020/12/16 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
The existence of closed null circular geodesics around black holes is one of the most intriguing predictions of general relativity. It has recently been conjectured that the radii of black-hole photonspheres are bounded from below by the simple relation rph\ensuremath≥(3)/(2)rH, where rH is the radius of the outer black-hole horizon. We here prove the validity of this conjecture for spherically symmetric hairy black-hole configurations whose radial pressure function P\ensuremath≡|r3p| decreases monotonically.