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Claude Cohen Tannoudji

Prix Nobel en 1997 pour le ralentissement et le piégeage des atomes par la lumière laser.

Ses travaux sont à la source des recherches actuelles de l'IFRAF.




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Accueil du site > Thèses et habilitations > « The two dimensional Bose gas in box potentials »

« The two dimensional Bose gas in box potentials »

PhD defense of Laura Corman, Thursday 2nd of June at 2 pm in room 2 at the Collège de France, 11 place Marcelin Berthelot

Thesis prepared at the Laboratoire Kastler Brossel under the supervision of Jean Dalibard and Jérôme Beugnon.

Abstract :

Degenerate atomic gases are a versatile tool to study many-body physics. They offer the possibility to explore low-dimension physics, which strongly differs from the three dimensional (3D) case due to the enhanced role of fluctuations. In this work, we study degenerate 2D Bose gases whose original in-plane confinement is uniform and of arbitrary shape. These 2D uniform traps, which we first developed on an existing set-up, were subsequently implemented on a new set-up using versatile optical potentials.

We present a series of experiments that take advantage of this flexible geometry. First, we study the static and dynamic behaviours of a uniform gas at the transition between a 3D normal and a 2D superfluid state. We observe the establishment of extended phase coherence, followed, as the gas is quench cooled, by the apparition of topological defects whose scaling is compared to the Kibble-Zurek prediction. Second, we present the first results of the new set-up : we investigate collective effects in light-matter interactions, where the resonance properties of a dense assembly of atoms are strongly modified with respect to the single atom ones.

Last, we develop two experimental proposals for the new set-up. The first one studies how a 2D gas can be uniformly evaporated using the tilted lattice providing the 2D confinement. In the second one, we propose to produce supercurrents in a deterministic way in ring-shaped traps either by condensing in an artificial gauge field or by implementing a topological vortex pump.

The jury is composed of Tilman Esslinger, Hélène Perrin, Zoran Hadzibabic and Gilles Montambaux.

Post-scriptum :

The defense will take place on Thursday 2nd of June at 2 pm in room 2 at the Collège de France, 11 place Marcelin Berthelot 75005 Paris.

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