The Geometric phase and fractional orbital angular momentum states in electron vortex beams
Abstract
We study here fractional orbital angular momentum (OAM) states in electron vortex beams (EVB) from the perspective of geometric phase. We have considered the skyrmionic model of an electron, where it is depicted as a scalar electron orbiting around the vortex line, which gives rise to the spin degrees of freedom. The geometric phase acquired by the scalar electron orbiting around the vortex line induces the spin-orbit interaction, which leads to the fractional OAM states with non-quantized monopole charge associated with the corresponding geometric phase. This involves tilted vortex in EVBs. The monopole charge undergoes the renormalization group (RG) flow, which incorporates a length scale dependence making the fractional OAM states unstable upon propagation. It is pointed out that when EVBs move in an external magnetic field, the Gouy phase associated with the Laguerre-Gaussian modes modifies the geometric phase factor and a proper choice of the radial index helps to have a stable fractional OAM state.
Keywords
Cite
@article{arxiv.1608.03562,
title = {The Geometric phase and fractional orbital angular momentum states in electron vortex beams},
author = {Pratul Bandyopadhyay and Banasri Basu and Debashree Chowdhury},
journal= {arXiv preprint arXiv:1608.03562},
year = {2017}
}
Comments
Accepted for publication in Phys. Rev.A