Coulomb sensing of single ballistic electrons

TL;DR

This paper demonstrates a method for sensing single ballistic electrons using remote Coulomb interactions, enabling nanoscale potential landscape characterization and multi-electron sensing with picosecond resolution.

Contribution

It introduces a novel scheme for sensing single ballistic electrons through controllable Coulomb interactions, advancing quantum electron control techniques.

Findings

Coulomb interactions are highly controllable via electron energy and timing.

Nanoscale potential landscape of the beam splitter can be characterized.

Multi-electron sensing achieved with picosecond resolution.

Abstract

While ballistic electrons are a key tool for applications in sensing and flying qubits, sub-nanosecond propagation times and complicated interactions make control of ballistic single electrons challenging. Recent experiments have revealed Coulomb collisions of counterpropagating electrons in a beam splitter, giving time resolved control of interactions between single electrons. Here we use remote Coulomb interactions to demonstrate a scheme for sensing single ballistic electrons. We show that interactions are highly controllable via electron energy and emission timing. We use a weakly-coupled `sensing' regime to characterise the nanoscale potential landscape of the beam splitter and the strength of the Coulomb interaction, and show multi-electron sensing with picosecond resolution.