Electron pairs on demand
Kontrollierte Emission und räumliche Aufspaltung von Elektronenpaaren nachgewiesen
A precise control and manipulation of quantum-mechanical states could pave the way for promising
applications such as quantum computers and quantum cryptography. In quantum optics, such experiments have already been performed for some time. This, for example, allows the controlled generation of pairs of entangled, but spatially separated photons, which are of essential importance for quantum cryptography. An analogous generation and spatial separation of entangled electrons in solids would be of fundamental importance for future applications, but could not be demonstrated yet. The results from Hannover and Braunschweig are a decisive step in this direction.
As an electron source, the physicists from Leibniz University Hannover and from PTB used so-called semiconductor single-electron pumps. Controlled by voltage pulses, these devices emit a defined number of electrons. The single-electron pump was operated in such a way that it released exactly one electron pair per pulse into a semiconducting channel. A semitransparent electronic barrier divides the channel into two electrically distinct areas. A correlation measurement then recorded whether the electron pairs traversed the barrier, or whether they were reflected or split by the barrier. It could be shown that for suitable parameters, more than 90 % of the electron pairs were split and spatially separated by the barrier. This is an important step towards the envisioned generation and separation of entangled electron pairs in semiconductor components.
Contact
Dr. Niels Ubbelohde, Working Group 2.53 Low-dimensional Electron Systems,
Phone: +49 (0)531 592-2534,
e-mail: niels.ubbelohde(at)ptb.de
The original publication:
Niels Ubbelohde, Frank Hohls, Vyacheslavs Kashcheyevs, Timo Wagner, Lukas Fricke, Bernd Kästner, Klaus Pierz, Hans W. Schumacher, Rolf J. Haug: Partitioning of on-demand electron pairs. Nature Nanotechnology (2014), doi: 10.1038/nnano.2014.275
http://www.nature.com/nnano/journal/vaop/ncurrent/full/nnano.2014.275.html