Vorschau

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Abstract

This thesis reports on the first realization of a two-particle Laughlin state – the quintessential building block of fractional quantum Hall states – in a rotating ultracold quantum gas. Utilizing a single atom and spin resolved imaging technique, we probe the Laughlin wavefunction and reveal its microscopic signatures: the suppression of interparticle interactions by incorporating angular momentum into the particles’ relative motion. In order to rotate few-fermion systems we develop a novel all-optical approach based on the interference of the optical trapping potential of the atoms with Laguerre-Gaussian beams. Since this method requires high quality optical light fields, we implement an advanced optical phase aberration correction technique by using the quantum gas itself as the wavefront sensor. We verify the imprint of the angular momentum from the rotating trap onto the atoms by transferring a single atom in an angular momentum eigenstate of the harmonic potential. To realize a Laughlin state, we prepare two repulsively interacting, spinful fermions in the ground state of the tweezer and subsequently turn on the trap rotation which coherently populates a state with angular momentum in the atoms’ relative motion. We identify the state as the Laughlin state based on the reconstructed density distribution and the second-order correlation functions.

This work establishes the foundation for assembling bosonic and fermionic fractional quantum Hall states in rotating atomic gases.