The topological charge m of vortex electrons spans an infinite-dimensional Hilbert space. Selecting a two-dimensional subspace spanned by m=±1, a beam electron in a transmission electron microscope (TEM) can be considered as a quantum bit (qubit) freely propagating in the column. A combination of electron optical quadrupole lenses can serve as a universal device to manipulate such qubits at the experimenter's discretion. We set up a TEM probe forming lens system as a quantum gate and demonstrate its action numerically and experimentally. High-end TEMs with aberration correctors are a promising platform for such experiments, opening the way to study quantum logic gates in the electron microscope.
Cite
@article{arxiv.2209.07123,
title = {A quantum logic gate for free electrons},
author = {Stefan Löffler and Thomas Schachinger and Peter Hartel and Peng-Han Lu and Rafal E. Dunin-Borkowski and Martin Obermair and Manuel Dries and Dagmar Gerthsen and Peter Schattschneider},
journal= {arXiv preprint arXiv:2209.07123},
year = {2023}
}