37 research outputs found
Comment on ''Inverse Doppler shift and control field as coherence generators for the stability in superluminal light''
In their study of inverse Doppler shift and superluminal light [Phys. Rev. A
91, 053807 (2015)], Ghafoor et al. consider a three-level atomic arrangement
with transitions in the optical domain. In fact, the values they give to the
parameters lead to a probe wavelength lying in the decimeter band. We point out
that the Doppler shifts are then negligible and remark that the simulations
performed by Ghafoor et al. do not evidence any superluminal effect
Comment on "Gain-assisted superluminal propagation and rotary drag of photon and surface polaritons"
In their study of superluminal propagation, rotary drag and surface
polaritons [Phys. Rev. A 96, 013848 and 049906(E) (2017)], Khan et al. consider
a four-level atomic arrangement with transitions in the optical domain. In
fact, the values they give to the parameters lead to a probe wavelength lying
in the decimeter band and we point out that, in such conditions, all their
results are irrelevant