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Superfluidité dans un gaz de fermions ultrafroids

Abstract : This manuscript is divided in two parts. The first one is devoted to the study of superfluidity in an ultra-cold Fermi gas. Using a degenerate lithium 6 gas close to a Feshbach resonance we have obtained a fermionic superfluid and studied its evolution as a function of the binding energy of the pairs. To characterize the resulting BEC-BCS crossover between a Bose-Einstein condensate of molecules and a BCS state of Cooper pairs, we have studied the expansion of the cloud without or with interactions. From these measurements we have extracted the momentum distribution of the system and studied its hydrodynamic behaviour. The second part concerns the conception and the builiding of a second generation apparatus. With respect to the old setup, its principal advantages are a gain of an order of magnitude in the number of trapped atoms, a good optical acces, an increased stability and reproducibility and a repetition rate five times bigger. The new apparatus has already allowed us to achieve quantum degeneracy of lithium 7 and will give acces to the simulation of condensed matter hamiltonians with ultra-cold Fermi gases.
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https://tel.archives-ouvertes.fr/tel-00429181
Contributor : Leticia Tarruell <>
Submitted on : Sunday, November 1, 2009 - 3:50:12 PM
Last modification on : Thursday, December 10, 2020 - 12:38:18 PM
Long-term archiving on: : Thursday, June 17, 2010 - 5:32:50 PM

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  • HAL Id : tel-00429181, version 1

Citation

Leticia Tarruell. Superfluidité dans un gaz de fermions ultrafroids. Physique Atomique [physics.atom-ph]. Université Pierre et Marie Curie - Paris VI, 2008. Français. ⟨tel-00429181⟩

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