Comment on "Deformed Fokker-Planck equation: inhomogeneous medium with a position-dependent mass"

TL;DR

This paper provides a microscopic derivation of the Langevin equation for particles in inhomogeneous media with position-dependent mass and damping, challenging previous phenomenological models.

Contribution

It introduces a new microscopic derivation of the Langevin equation, differing from the phenomenological approach in the referenced study.

Findings

Derivation shows differences from previous phenomenological models

Highlights importance of microscopic foundations in inhomogeneous systems

Provides insights into particle dynamics with position-dependent properties

Abstract

In a recent paper by B. G. da Costa {\it et al.} [Phys. Rev. E 102, 062105(2020)], the phenomenological Langevin equation and the corresponding Fokker-Planck equation for an inhomogeneous medium with a position-dependent particle mass and position-dependent damping coefficient have been studied. The aim of this comment is to present a microscopic derivation of the Langevin equation for such a system. It is not equivalent to that in the commented paper.