Obstructions to minimal regular black hole cosmologies
Phys. Rev. D 114, 044077 – Published 24 August, 2026
DOI: https://doi.org/10.1103/qs86-npwk
Abstract
We derive an obstruction to Friedmann–Lemaître–Robertson–Walker (FLRW) daughter cosmologies from static, asymptotically flat regular black holes. The trapped region of such a parent is Kantowski–Sachs rather than FLRW, so the daughter must be introduced as a separate matched region. For closed daughters, the angular Darmois condition is controlled by the Misner–Sharp mass: asymptotic flatness and finite Arnowitt–Deser–Misner mass force the induced density to decay as , while the curvature term scales as . The minimal closed branch is therefore bounded rather than indefinitely expanding. Flat and open daughters avoid this boundedness mechanism. For their maximal homogeneous FLRW continuations, the regular-end affine-averaged null energy condition (ANEC) theorem excludes simultaneous nonstaticity, curvature regularity, null geodesic completeness, and ANEC consistency. For Bardeen, the parent source does not naturally supply the late-time support needed for an unbounded closed daughter. Within these criteria, a viable FLRW daughter therefore requires additional structure, such as modified asymptotics, nonminimal matching, non-FLRW evolution, or an additional stress-energy component.