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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 > Atomic interferometers in an optical lattice

Atomic interferometers in an optical lattice

PhD thesis defense of Bruno Pelle

Wednesday 16th of October 2013 at 14h in the amphitheatre of the Institut d’Astrophysique de Paris

Abstract :

The aim of the ForCa-G project, for Casimir force and short range Gravitation, lies into the measurement of short range forces between atoms and a mirror using atomic interferometry techniques. In that region, the predominant force is the one of Casimir-Polder which is an electromagnetic force applying between neutral atoms and a surface. Moreover, a precise measure of this force would allow to pursue the search for potential deviations of Newton’s law, forecasted in the frame of unification theories of the four fundamental interactions.

The work realized during this thesis constitutes a demonstration of principle of this project, with atoms set far from the mirror. Cold atoms are trapped in numerous potential wells generated by an optical lattice. We measure the gravitationnal potential energy increment between two wells of this lattice, represented by the Bloch frequency νB. To realize this measurement, we use the principle of quantum states superposition where a state of ubiquity is generated with atoms localized in two different wells at the same moment. Finally, from the evolution of their atomic phase, we determine the potential difference experienced by the atoms in this atomic interferometer.

This work presents the study of different atomic interferometers in this optical lattice, characterized in terms of sensitivity and systematics on the Bloch frequency measurement. The Accordion interferometer gives a relative sensitivity of σδνB /νB = 9.0×10−6 at 1 s, which integrates until σδνB /νB = 1.9×10−7 in 2 800 s. This corresponds to a state-of-the-art measurement of the gravity acceleration g for a trapped atomic gravimeter.


Post-scriptum :

Institut d’Astrophysique de Paris
98 bis boulevard Arago, 75014 Paris.
This amphitheatre is also accessible from the Observatoire de Paris
77 avenue Denfert-Rochereau
75014 Paris

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