Evolution of a twisted electron wave packet perturbed by an inhomogeneous electric field

TL;DR

This paper investigates how inhomogeneous electric fields influence the structure and dynamics of twisted electron wave packets, revealing mechanisms for vortex splitting and potential control of matter wave beams.

Contribution

It introduces a perturbative analysis of electron Laguerre-Gaussian wave packets under external electric fields, showing how their vortex structures can be manipulated.

Findings

Electric fields can significantly distort wave packet structures.

Degenerate zeros split into multiple vortices under perturbation.

Insights into controlling twisted matter beams and their stability.

Abstract

Laguerre-Gaussian (LG) wave packets, known for their vortex structure and nonzero orbital angular momentum (OAM), are of great interest in various scientific fields. Here we study the nonrelativistic dynamics of a spatially-localized electron LG wave packet interacting with an inhomogeneous external electric field that violates the axial symmetry of the initial wave function. We focus on the analysis of the electron density and demonstrate how it is affected by the external field. Within the first order of perturbation theory, we calculate the electron wave function and reveal that the electric field may significantly alter the wave packet's structure and distort its qualitative form. We demonstrate that due to the interaction with the external field, the degenerate zeros of the initial wave function located on the $z$ axis split into multiple nondegenerate nodes in the transverse plane representing separate single-charge vortices. This mechanism resembles the analogous effects known in topological optics. These findings provide new insights into controlling and manipulating twisted matter beams and into their possible instabilities.