Artificial Gauge Fields and Topological Effects in Quantum Gases

Abstract

This thesis first proposes to generate an artificial non-Abelian U (3) gauge field by using a 2-tripod scheme, namely two tripod configurations sharing a common ground state level and driven by resonant 1-photon transitions. Using an appropriate combination of four Laguerre-Gauss and two Hermite-Gauss laser beams, we are able to produce a U (3)-monopole and a U (3) spin-orbit coupling for both alkali and alkaline-earth atoms. In the second part of this thesis, we provide a simple experimental scheme to generate topological spin textures in the ground state of interacting ultracold bosonic atoms loaded in a two-dimensional harmonic trap. Using a Gross-Pitaevskii description, we show that the ground state of the atomic system has different topological properties depending on the interaction strength and the laser beam intensity. A half-skyrmion state develops at low interactions while a meron pair develops at large interactions.