# Free-Electron Qubits

## TL;DR

This paper proposes using laser-driven nanophotonic interactions to turn free electrons into qubits, demonstrating control, measurement, and gate implementation within current femtosecond-pulsed laser microscopy capabilities.

## Contribution

It introduces a method to create and manipulate free-electron qubits using laser interactions, including implementing universal single-qubit gates.

## Key findings

- Demonstrated how to implement non-commutative spin algebra for free electrons.
- Showed control and measurement of free-electron qubit states.
- Proposed laser parameters for qubit manipulation within existing technology.

## Abstract

Free-electron interactions with laser-driven nanophotonic nearfields can quantize the electrons' energy spectrum and provide control over this quantized degree of freedom. We propose to use such interactions to promote free electrons as carriers of quantum information and find how to create a qubit on a free electron. We find how to implement the qubit's non-commutative spin-algebra, then control and measure the qubit state with a universal set of 1-qubit gates. These gates are within the current capabilities of femtosecond-pulsed laser-driven transmission electron microscopy. Pulsed laser driving promise configurability by the laser intensity, polarizability, pulse duration, and arrival times.

---
Source: https://tomesphere.com/paper/1907.10281