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In their study of superluminal propagation, rotary drag and surfacepolaritons [Phys. Rev. A 96, 013848 and 049906(E) (2017)], Khan et al. considera four-level atomic arrangement with transitions in the optical domain. Infact, the values they give to the parameters lead to a probe wavelength lyingin the decimeter band and we point out that, in such conditions, all theirresults are irrelevant.

Comment on "Gain-assisted superluminal propagation and rotary drag of photon and surface polaritons"