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Q: Fachverband Quantenoptik und Photonik
Q 16: Poster: Quantum information, micromechanical oscillators, matter wave optics, precision measurements and metrology
Q 16.43: Poster
Montag, 17. März 2014, 16:30–18:30, Spree-Palais
Towards a loophole free test of Bell’s inequality with atoms entangled over a large distance — •Daniel Burchardt1, Norbert Ortegel1, Kai Redeker1, Julian Hofmann1, Michael Krug1, Markus Rau1, Wenjamin Rosenfeld1,2, and Harald Weinfurter1,2 — 1Ludwig-Maximilians-Universität, München — 2Max-Planck-Institut für Quantenoptik, Garching
Bell’s inequality allows to exclude local hidden variable theories for physical description. Up to now all experiments suffered from at least one of the two loopholes resulting either from low detection efficiency or from lack of space-like separation of the measurements.
We present our progress towards a Bell experiment where the two sites are separated by 400 m. This long distance entanglement is obtained in two steps. First, 87Rb atoms are entangled with spontaneously emitted photons and second, a Bell-measurement on the photons transfers the entanglement to the atoms. This scheme provides a heralding signal every time the atoms are entangled. To achieve space-like separation, the atomic states are read out within one microsecond using state selective ionization and a fast detection of the ionization fragments. This time already includes the random choice of the measurement basis which is obtained by a quantum random number generator. The short measurement time together with the large distance and the efficient state read-out of the atoms fulfills the requirements to close both the detection and the locality loophole in a single experiment.