2021/03/31 by Viraf M. Mehta, Mehmet Demirtas, Cody Long +4 · 2 citations
Physics and Astronomy · #Astrophysical Phenomena and Observations #Axion #Black Holes and Theoretical Physics #Black hole (networking) #Cosmology and Gravitation Theories #Moduli #Realization (probability) #String (physics) #String theory #Superradiance #astro-ph.CO #hep-ph #hep-th
paper · pdf · doi:10.1088/1475-7516/2021/07/033
35+23 pages, 23 figures. v2: minor corrections and clarifications
openalex created_date 2021/03/15 · arxiv created 2021/05/17 · openalex publication_date 2021/07/01 · arxiv updated 2021/08/04 · openalex updated_date 2026/08/06
Abstract We perform an extensive analysis of the statistics of axion masses and interactions in compactifications of type IIB string theory, and we show that black hole superradiance excludes some regions of Calabi-Yau moduli space. Regardless of the cosmological model, a theory with an axion whose mass falls in a superradiant band can be probed by the measured properties of astrophysical black holes, unless the axion self-interaction is large enough to disrupt formation of a condensate. We study a large ensemble of compactifications on Calabi-Yau hypersurfaces, with 1 ≤ h 1,1 ≤ 491 closed string axions, and determine whether the superradiance conditions on the masses and self-interactions are fulfilled. The axion mass spectrum is largely determined by the Kähler parameters, for mild assumptions about the contributing instantons, and takes a nearly-universal form when h 1,1 ≫ 1. When the Kähler moduli are taken at the tip of the stretched Kähler cone, the fraction of geometries excluded initially grows with h 1,1 , to a maximum of ≈ 0.5 at h 1,1 ≈ 160, and then falls for larger h 1,1 . Further inside the Kähler cone, the superradiance constraints are far weaker, but for h 1,1 ≫ 100 the decay constants are so small that these geometries may be in tension with astrophysical bounds, depending on the realization of the Standard Model.