2024/12/04 by Matthew Heydeman, Heydeman, Matthew, Chiara Toldo +1 · 2 citations
Mathematics · Physics and Astronomy · #Algebraic Geometry and Number Theory #Black Holes and Theoretical Physics #FOS: Physical sciences #General Relativity and Quantum Cosmology (gr-qc) #High Energy Physics - Theory (hep-th) #History and Theory of Mathematics
paper · pdf · doi:10.48550/arxiv.2412.03695
openalex publication_date 2024/12/04 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
For a variety of BPS black holes in string theory, the supersymmetric index has provided a microscopic validation of the Bekenstein-Hawking formula. In the near-BPS limit, a gravitational path integral analysis previously revealed the semiclassical spectrum is modified, having a large extremal degeneracy (consistent with the index) and a mass gap up to a continuum of non-BPS black holes. Presently, we study examples in which these sharp features of the spectrum are altered due to the presence of anomalies in the form of ϑ-angle terms in the action. These may appear generally, but we focus on near-BPS dyonic AdS4 black holes in M-theory, dual to 3d N=2 SCFTs of Class R obtained by twisted compactification of N wrapped M5 branes. Due to the Witten effect, the dyonic black holes receive quantum corrections to their charges, and when ϑ = π one may find a mixed `t Hooft anomaly between the U(1)R and ℤ2 time reversal symmetries. Using results from N=2 JT supergravity, we find these effects result in a spectrum in which both the gap and index are reduced, and may even vanish. Surprisingly, for ϑ → π, neither the Bekenstein-Hawking formula nor the index correctly account for the extremal degeneracies.