Two electrons interacting at a mesoscopic beam splitter

authored by
Niels Ubbelohde, Lars Freise, Elina Pavlovska, Peter G. Silvestrov, Patrik Recher, Martins Kokainis, Girts Barinovs, Frank Hohls, Thomas Weimann, Klaus Pierz, Vyacheslavs Kashcheyevs
Abstract

The nonlinear response of a beam splitter to the coincident arrival of interacting particles enables numerous applications in quantum engineering and metrology. Yet, it poses considerable challenges to control interactions on the individual particle level. Here, we probe the coincidence correlations at a mesoscopic constriction between individual ballistic electrons in a system with unscreened Coulomb interactions and introduce concepts to quantify the associated parametric nonlinearity. The full counting statistics of joint detection allows us to explore the interaction-mediated energy exchange. We observe an increase from 50% up to 70% in coincidence counts between statistically indistinguishable on-demand sources and a correlation signature consistent with the independent tomography of the electron emission. Analytical modelling and numerical simulations underpin the consistency of the experimental results with Coulomb interactions between two electrons counterpropagating in a quadratic saddle potential. Coulomb repulsion energy and beam splitter dispersion define a figure of merit, which in this experiment is demonstrated to be sufficiently large to enable future applications, such as single-shot in-flight detection and quantum logic gates.

Type
Article
Journal
Nature nanotechnology
Volume
18
Pages
733-740
No. of pages
8
ISSN
1748-3395
Publication date
07.2023
Publication status
Published
Peer reviewed
Yes
ASJC Scopus subject areas
Condensed Matter Physics, Bioengineering, Atomic and Molecular Physics, and Optics, Materials Science(all), Electrical and Electronic Engineering, Biomedical Engineering
Electronic version(s)
https://doi.org/10.1038/s41565-023-01370-x (Access: Unknown)