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Etats comprimés atomiques sur puce à atomes

Abstract : In this thesis, we describe the construction of an experiment, allowing to produce 87Rb Bose-Einstein condensates on an atom chip, and then split them in a double well potential. An accurate imaging system has been developped, in order to be able to measure the absolute value of the populations of the double well within a very low noise level, almost limited by the optical shot noise. We measure atom number statistics after splitting, and directly observe number squeezed states, down to −4.9 dB at low temperatures, compared to a classical gas, of independent particules. The dependance in temperature of fluctuations has been also studied. For a thermal gas, poissonian fluctuations are given by the probability distribution of the macroscopic configurations with a given atomnumber difference. In the degenerate regime, the entropy effect which favors small number differences vanishes, leading to super-poissonian fluctuations, tomore than +3.8 dB close to transition temperature. At low temperatures, the interaction energy cost associated with number fluctuations exceeds the available thermal energy, leading to sub-poissonian fluctuations. Those two behaviours have been theoreticaly explained, both with a simple analytical model and a numerical one. We also measured the evolution of the relative phase between the two clouds, and its collapse due to interactions, allowing us to claim that this splitter is a coherent one.
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Contributor : Kenneth Maussang <>
Submitted on : Saturday, April 30, 2011 - 11:00:35 PM
Last modification on : Thursday, December 10, 2020 - 12:38:41 PM
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  • HAL Id : tel-00589713, version 1


Kenneth Maussang. Etats comprimés atomiques sur puce à atomes. Physique Atomique [physics.atom-ph]. Université Pierre et Marie Curie - Paris VI, 2010. Français. ⟨tel-00589713⟩



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