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

We investigate the quasi-normal modes (QNMs) under the gravitational field perturbations and the grey-body factors for a class of regular black holes with sub-Planckian curvature and Minkowski core. Specifically, we compute the QNMs with the pseudospectral method and the WKB method. It is found that as the deviation parameter of the regular black hole changes, the trajectory of the QNMs displays non-monotonic and spiral behavior. Then we compute the grey-body factors with the WKB method and compare them with the results obtained by the correspondence relation recently revealed in [1]. We find the discrepancy exhibits minor errors, indicating that this relation is effective for computing the grey-body factors of such regular black holes.