Quantum mechanical formulation of the Busch theorem

TL;DR

This paper explores the quantum mechanical principles behind generating vortex electron beams in electron microscopes using a solenoid-immersed cathode, extending the technique's potential for studying magnetic structures.

Contribution

It provides a quantum mechanical formulation for the Busch theorem and discusses conditions for creating vortex electron beams in microscopes, a novel application of the immersed cathode method.

Findings

Quantum formulation of vortex beam generation

Conditions for vortex electron beams in microscopes

Potential for producing vortex beams of other charged particles

Abstract

Electron vortex beams offer unique opportunities for the study of chiral or magnetic structures in electron microscopes and of fundamental effects of quantum interference in particle physics. Immersing a cathode in a solenoid field presents a highly efficient and flexible method for the generation of vortex electron beams which is utilized at accelerators, but has not yet been realized in an electron microscope. The conditions for the generation of vortex beams with quantized orbital angular momentum from an immersed cathode in an electron microscope are discussed, and general possibilities of this technique for the production of vortex beams of other charged particles are pointed out.