Integrable inhomogeneous NLS equations are equivalent to the standard NLS

TL;DR

This paper demonstrates that a class of claimed novel integrable inhomogeneous NLS equations are actually equivalent to the standard NLS, clarifying their integrability properties and dismissing their novelty.

Contribution

It proves that these inhomogeneous NLS equations are not new but equivalent to the standard NLS, simplifying the understanding of their integrability.

Findings

Inhomogeneous NLS equations are equivalent to standard NLS.

This equivalence explains their integrability features.

Claims of novelty for these equations are invalid.

Abstract

A class of inhomogeneous nonlinear Schr\"odinger equations (NLS), claiming to be novel integrable systems with rich properties continues appearing in PhysRev and PRL. All such equations are shown to be not new but equivalent to the standard NLS, which trivially explains their integrability features.