On the Hartman paradox, electromagnetic wave tunneling and supraluminal velocities (comment on the paper "Tunneling of electromagnetic waves: paradoxes and prospects" by A B Shvartsburg)

Some paradoxes are discussed concerning the interpretation of the passage of particles and electromagnetic waves (pulses) across potential barriers and through nonuniform media, in particular, those with frequency dispersion and therefore dissipation. It is emphasized that a rigorous nonstationary approach does not entail any supraluminal velocities for the transfer of physical substances, although supraluminal velocities are indeed possible for several kinematically defined velocities, e.g., for the group velocity.