Comparing entanglement degradation among singular and regular black holes

We investigate how black-hole geometries characterized by more than the mass parameter alone, affect the degradation of bipartite entanglement near horizons. We consider a maximally entangled state composed of two massless scalar-field modes, shared by an inertial observer (Alice) and a static observer (Rob) who is hovering close to a black-hole horizon. We employ a local near-horizon Rindler approximation of the black hole geometry, to compute the entanglement negativity as a function of Rob’s proper acceleration and mode frequency. We compare the results for Schwarzschild, Reissner–Nordström, Bardeen, Hayward, and Schwarzschild–de Sitter geometries. We find that entanglement degradation depends strongly on the geometry: Reissner–Nordström shows a non-monotonic behavior, while regular black holes typically preserve more entanglement than Schwarzschild. Highfrequency modes consistently experience less degradation than low-frequency ones.