Stuttgart 2012 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 54: Poster 3
Q 54.47: Poster
Donnerstag, 15. März 2012, 16:30–19:00, Poster.I+II
Entanglement of two single atoms over a distance of 20m — •Norbert Ortegel1, Michael Krug1, Julian Hofmann1, Kai Redeker1, Lea Gérard1, Wenjamin Rosenfeld1,2, Markus Weber1, and Harald Weinfurter1,2 — 1Department für Physik, LMU München, Schellingstraße 4, 80799 München — 2Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Straße 1, 85748 Garching
Atom pairs entangled over long distances can serve as basic elements in quantum communication schemes e.g. the quantum repeater. They can also be used to carry out fundamental tests of quantum mechanics such loophole free tests of Bells inequality. Recently, we generated entanglement between two single Rb87 atoms that are located in independent optical dipole traps 20 meters apart.
In our case entanglement between the atoms is obtained via the entanglement swapping protocol. In this contribution we present details on the tools and methods used to perform such an experiment. It starts by creating entanglement between the electronic spin state of each atom and the polarization state of a photon. The photons are then brought together via an actively stabilized fiber link without loss of coherence. A Bell-state projection of the two-photon state by two-photon interference at a fiber beamsplitter yields an entangled atom pair. In order to preserve the entanglement the atomic spin state is stabilized by actively compensating external magnetic fields. Finally, a state-readout of the atoms reveals the non-classical correlations that prove their entanglement.