Realization of a spin-1 Bose-Einstein condensation experiment

Abstract

This thesis is devoted to the construction, optimization and characterization of an experimental apparatus, capable of creating spinor condensates of ~1x10^5 atoms with a repetition rate of 10s, using an all-optical evaporation technique. I report a complete description of the experimental apparatus and techniques used in the experiment and a characterization of the BEC sample. We study the transmission of absorption imaging pictures through a coherent fiber bundle. We show that the fiber bundle introduces spurious noise in the picture mainly due to the strong core-to-core coupling. We demonstrate that we can retrieve exact quantitative information about the atomic system using this technique. We also explore the equilibration dynamics of ferromagnetic spin-1 system as a function of the initial magnetization of the sample and the external magnetic field. We show that the magnetization of the system is conserved despite of the presence of dissipative processes that are intrinsic to any experiment. We investigated the formation of the BEC in a spin-1 quantum gas in the presence of an external magnetic field. We report on the spontaneous magnetization of the condensate fraction during the evaporation process at low magnetic fields. We as well observe multi-step condensation, and found signatures of a possible interspecies Feshbach resonance

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