Skip to Main content Skip to Navigation
Theses

ETUDE DES TECHNIQUES DE PRODUCTION DE CONDENSATS DE BOSE-EINSTEIN / EVAPORATION MULTI-FREQUENCE ET REFROIDISSEMENT SYMPATHIQUE

Guillaume Delannoy 1
1 laboratoire Charles Fabry de l'Institut d'Optique / Optique atomique
LCFIO - Laboratoire Charles Fabry de l'Institut d'Optique
Abstract : This thesis discusses several topics concerning Bose-Einstein condensation. We present two alternative techniques to produce Bose condensates and an application of the condensates : atom lasers. Our experimental setup uses an iron-core electromagnet to generate a magnetic trap. The magnetic field strength at the center of the trap is of the order of one hundred Gauss. With such a large bias field, radio-frequency-induced evaporative cooling is found to be hampered, and eventually interrupted, by the presence of nonlinear Zeeman shifts. To solve this problem, we use a multi-frequency evaporation scheme. We have also produced Bose-Einstein condensates simultaneously in two internal states by sympathetic cooling. A thermodynamic model allows us to understand the different scenarios observed experimentally. Furthermore, a calculation of the thermalization rate via elastic collisions gives a condition for the two components to stay in thermal contact during the sympathetic cooling process. Finally, we have produced and studied atomic beams generated by rf-output coupling of ultra-cold atomic clouds. With our high magnetic field, the relative stability required to obtain continuous beams is about 1:10 000. When the magnetic field is not stable enough, we show that a modulation of the frequency or of the amplitude of the rf field allows to stabilize the flux of the atom laser.
Complete list of metadatas

https://pastel.archives-ouvertes.fr/tel-00003840
Contributor : Philippe Bouyer <>
Submitted on : Wednesday, November 26, 2003 - 4:47:47 PM
Last modification on : Wednesday, October 14, 2020 - 3:56:56 AM
Long-term archiving on: : Monday, September 20, 2010 - 11:46:25 AM

Identifiers

  • HAL Id : tel-00003840, version 2

Citation

Guillaume Delannoy. ETUDE DES TECHNIQUES DE PRODUCTION DE CONDENSATS DE BOSE-EINSTEIN / EVAPORATION MULTI-FREQUENCE ET REFROIDISSEMENT SYMPATHIQUE. Physique Atomique [physics.atom-ph]. Université Paris Sud - Paris XI, 2001. Français. ⟨tel-00003840v2⟩

Share

Metrics

Record views

764

Files downloads

753