# Piégeage magnétiques d'atomes de Rudibium au voisinage d'une surface supraconductrice

Abstract : Atom-chip experiments aim at realizing a magnetic micro-trapping and at manipulating precisely an atomic cloud cooled down to a few micro-kelvins. This can be achieved by using the magnetic field generated by currents carried by micrometer-sized conductors designed on a substrate. The presence of a surface at a distance as close as a few tens of micrometers from the atomic cloud can disturb the trapping. The magnetic field fluctuations induced by the current noise in the chip result in atomic losses and decrease the lifetime in the trap. This noise is due to the non-zero resistivity of the metal used in the chip (Johnson-Nyquist noise).

Theoretical models presented here suggest that the use of superconducting wires may reduce these losses. The effect of the vortex lattice in the superconductor on the magnetic near-field is analysed as well. In this work, we also describe the cryogenic setup and the experimental sequence that have led to the observation of the first magnetic trap on a superconducting atom-chip. The lifetime in this trap at a distance of 440~$\mu$m from the surface reaches 2 minutes which is very promising. We eventually present the RF-cooling stage until the achievement of Bose-Einstein condensation.
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https://tel.archives-ouvertes.fr/tel-00410067
Contributor : Thomas Nirrengarten <>
Submitted on : Monday, August 17, 2009 - 9:46:15 AM
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• HAL Id : tel-00410067, version 1

### Citation

Thomas Nirrengarten. Piégeage magnétiques d'atomes de Rudibium au voisinage d'une surface supraconductrice. Physique Atomique [physics.atom-ph]. Université Pierre et Marie Curie - Paris VI, 2007. Français. ⟨tel-00410067⟩

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