Recent theoretical studies show the possibility of generating optical gauge potentials in neutral atoms using laser beams carrying orbital angular momentum. This is interesting not only because the gauge field is related to a variety of important quantum phenomena in physics, such as the Aharonov-Bohm effect, geometric phases, and the quantum Hall effect, but also due to the fact that a vector-potential type of interaction on the center of mass of neutral atoms cannot be achieved directly by applying a magnetic field. With the versatility of cold atomic systems and advanced experimental techniques available in atomic and optical physics, the generation of gauge fields in neutral atoms makes cold atomic systems an ideal playground for investigating numerous single- or many-body effects...[ Read more ]

Recent theoretical studies show the possibility of generating optical gauge potentials in neutral atoms using laser beams carrying orbital angular momentum. This is interesting not only because the gauge field is related to a variety of important quantum phenomena in physics, such as the Aharonov-Bohm effect, geometric phases, and the quantum Hall effect, but also due to the fact that a vector-potential type of interaction on the center of mass of neutral atoms cannot be achieved directly by applying a magnetic field. With the versatility of cold atomic systems and advanced experimental techniques available in atomic and optical physics, the generation of gauge fields in neutral atoms makes cold atomic systems an ideal playground for investigating numerous single- or many-body effects related to magnetic fields.

In this thesis, we study optically generated gauge potentials and their effects in cold atoms. We show that gauge potentials well known in condensed matter physics, such as the “flux tube” magnetic field and the quasi-constant magnetic field, can be generated by two Laguerre-Gaussian beams. The “flux tube” magnetic field can be used to engineer both the phase and amplitude pattern of atomic wave functions, and drive atoms to a vortex state or a non-vortex state determined by its flux. Especially, with wisely chosen trapping potential and laser parameters, the atomic wave function is identical to phasor amplitude of the Laguerre-Gaussian beams. This is a remarkable result since all information of the optical modes is fully stored in the atomic wave, hence providing a possible means for storage of quantum qubits. Another intriguing application of these optical gauge potentials is spin current generation. We show that a persistent spin current, a static spin accumulation, and the atomic spin Hall effect, can all be generated in cold atoms.