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Claude Cohen Tannoudji

Prix Nobel en 1997 pour le ralentissement et le piégeage des atomes par la lumière laser.

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Accueil du site > Thèses et habilitations > Trapped Atom Clock on a Chip - Identical Spin Rotation Effects in an Ultracold Trapped Atomic Clock

Trapped Atom Clock on a Chip - Identical Spin Rotation Effects in an Ultracold Trapped Atomic Clock

PhD thesis defense of Christian Deutsch

19th of October 2011 in the amphitheatre (lecture hall) of the Institut d’Astrophysique de Paris, 98 bis boulevard Arago.

Abstract :

We describe precision spectroscopy experiments conducted on magnetically trapped Rb 87 atoms. A two photon transition links the clock hyperfine states |F = 1 ;mF = -1> and |F = 2 ; mF = 1> of the ground state manifold. Spatial clock frequency shifts in the trap are minimized by balancing second order Zeeman and cold-collision shifts enabling large dephasing times. The setup is designed to demonstrate a compact secondary frequency standard with relative stability of a few 10^(-13) t^(-1/2).

We explain the theoretical concepts of the experiment, its experimental realization and characterize the actual short term clock performance of 6.6x10^(-13) t^(-1/2).

In the regime of quantum collisions we examine a novel spin rephasing mechanism based on the identical spin rotation effect. This mechanism effectively inhibits the dephasing of the non-degenerate atomic ensemble. We observe the Ramsey fringe contrast and the transition frequency in the strong synchronisation limit with freezed dephasing dynamics. In the intermediately synchronizing regime it leads to the occurrence of characteristic contrast revivals.

The thesis was realized under the supervision of Jakob Reichel at the Paris Observatory in close collaboration between the Laboratoire Kastler Brossel and the Systèmes de Référence Temps-Espace.


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