# Comment on 'Relativistic electron wavepackets carrying angular momentum'

## TL;DR

This paper clarifies differences between light beam vortices and relativistic electron vortices, emphasizing the importance of two length scales and the role of gauge transformations in vortex structures.

## Contribution

It highlights subtle distinctions between light and electron vortices and discusses the significance of length scales and gauge transformations in electron vortex structures.

## Key findings

- Light and electron vortices are fundamentally different.
- Two length scales are crucial for understanding electron vortices.
- Gauge transformations can admit vortex structures in the Gordon current.

## Abstract

This is a comment on arXiv:1611.04445 (PRL, 118, 114801 (2017)). It is pointed out that the fundamental problems in light beam vortices and the relativistic electron vortices are not identical and have subtle differences. The significance of two length scales is underlined for the electron vortices. Local gauge transformation on the Gordon current admits vortex structure.