Controle de corrélations EPR et Bell dans des condensats de Bose-Einstein – CEBBEC

The CEBBEC project is undertaking several parallel investigations of entangled atoms and their possible use in quantum metrology. On the experimental front, both the LCF group in Palaiseau France and the LUH group in Hannover, Germany have succeeded in producing entangle atoms with spatial separations. They each used experimental protocols developed in their respective groups. The LCF group produced pairs of atoms which will be appropriate for a Bell inequality test, while the LUH group produced clouds of many atoms which will allow tests of entanglement with larger samples. This work was carried out with the collaboration of the BILBAO group. The TUW group has published a method of producing entangled samples using double well potentials on an atom chip an experimental work is proceeding to realise this idea. The LCF group also published an intermediate result concerning the observed statistics of their atom pair source. They show that the statistics are thermal and account very well for the observed contrast in their atomic Hong-Ou-Mandel experiment. The original experiment from 2015 was repeated recently to confirm the predicted contrast.

The consortium has been concentrating on experimental and theoretical methods to realize and exploit multipartite entanglement in atomic systems to improve atom interferometry protocols. Since the beginning of the project the experimental groups have successfully demonstrated two protocols for realizing entangled, and spatially separated atomic ensembles. Bell inequality and Einstein Rosen Podolsky tests are being planned and should be implemented by the end of the project. The theoretical groups have been working on advanced methods to take advantage of these quantum correlations, and the development of sophisticated techniques to characterize and quantify the entanglement. The consortium is collectively working towards using these ideas to improve the performance of atom interferometers.

On the experimental front, we have succeeded in producing entangled atoms with spatial separations. The LCF group produced pairs of atoms which will be appropriate for a Bell inequality test, while the LUH group produced clouds of many atoms which will allow tests of entanglement with larger samples. The TUW in Vienna group has published a method of producing entangled samples using double well potentials on an atom chip an experimental work is proceeding to realise this idea. The LCF group also published an intermediate result concerning the observed statistics of their atom pair source. They show that the statistics are thermal and account very well for the observed contrast in their atomic Hong-Ou-Mandel experiment.

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