Correspondence between grey-body factors and quasinormal modes for regular black holes with sub-Planckian curvature*

Abstract We investigate the quasi-normal modes (QNMs) under gravitational field perturbations and grey-body factors for a class of regular black holes with sub-Planckian curvature and Minkowski core. We compute the QNMs with the pseudospectral and WKB methods. The trajectory of the QNMs displays non-monotonic and spiral behavior with changes in the deviation parameter of the regular black hole. Subsequently, we compute the grey-body factors with the WKB method and compare them with the results obtained by the correspondence relation recently revealed in [R. A. Konoplya and A. Zhidenko, JCAP 09 , 068 (2024)]. We find that the discrepancy exhibits minor errors, indicating that this relation is effective for computing the grey-body factors of such regular black holes.