  We address the impact of sterile fermions on charged lepton electric dipole
moments. Any experimental signal of these observables calls for scenarios of
physics beyond the Standard Model providing new sources of CP violation. In
this work, we consider a minimal extension of the Standard Model via the
addition of sterile fermions which mix with active neutrinos and we derive the
corresponding analytical expressions for the electric dipole moments of charged
leptons at two-loop order. Our study reveals that, in order to have a
non-vanishing contribution in this framework, the minimal extension
necessitates the addition of at least 2 sterile fermion states to the Standard
Model field content. Our conclusion is that sterile neutrinos can give
significant contributions to the charged lepton electric dipole moments, some
of them lying within present and future experimental sensitivity if the masses
of the non-degenerate sterile states are both above the electroweak scale. The
Majorana nature of neutrinos is also important in order to allow for
significative contributions to the charged lepton electric dipole moments. In
our analysis we impose all available experimental and observational constraints
on sterile neutrinos and we further discuss the prospect of probing this
scenario at low and high energy experiments.
