Single-electron entanglement and nonlocality

TL;DR

This paper demonstrates that a single electron in a superposition of spatial modes can be considered entangled and nonlocal, with theoretical and experimental evidence supporting its observability in electronic systems.

Contribution

It provides a theoretical demonstration and an experimental scheme showing single-electron entanglement and nonlocality using current measurements in electron quantum optics.

Findings

Deterministic Bell inequality violation with single-electron states.

Single-electron entanglement detectable via current measurements.

Experimental scheme feasible under realistic conditions.

Abstract

Motivated by recent progress in electron quantum optics, we revisit the question of single-electron entanglement, specifically whether the state of a single electron in a superposition of two separate spatial modes should be considered entangled. We first discuss a gedanken experiment with single-electron sources and detectors, and demonstrate deterministic (i. e. without post-selection) Bell inequality violation. This implies that the single-electron state is indeed entangled and, furthermore, nonlocal. We then present an experimental scheme where single-electron entanglement can be observed via measurements of the average currents and zero-frequency current cross-correlators in an electronic Hanbury Brown-Twiss interferometer driven by Lorentzian voltage pulses. We show that single-electron entanglement is detectable under realistic operating conditions. Our work settles the question of single-electron entanglement and opens promising perspectives for future experiments.