Generalized Drude model and electromagnetic screening in metals and superconductors

Electromagnetic screening is studied from the perspective of fluid mechanics by generalizing the Drude theory, which unifies three known results:Thomas-Fermi screening of the longitudinal field in both metals and superconductors, the skin effect of the transverse field in metals, and the Meissner effect in superconductors. In the special case of superfluid electrons, we slightly generalize the London equations to incorporate the longitudinal electric fields. Moreover, regarding the experiments, our study points out that the dynamical measurement may overestimate the superfluid density.