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

## TL;DR

This paper critically examines a previous study on superluminal propagation and surface polaritons, highlighting that the parameter choices made in that work lead to physically irrelevant results due to the probe wavelength being in the decimeter range.

## Contribution

The authors provide a critical commentary clarifying the physical relevance of parameter choices in the prior work on superluminal phenomena.

## Key findings

- Previous parameter choices are physically irrelevant due to wavelength issues
- The study's results do not apply to optical domain conditions
- Highlights importance of realistic parameter selection in superluminal research

## Abstract

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.