Review: Spin-orbit coupling in atomic gases
Spin–orbit coupling links a particle’s velocity to its quantum-mechanical spin, and is essential in numerous condensed matter phenomena, including topological insulators and Majorana fermions. In solid-state materials, spin–orbit coupling originates from the movement of electrons in a crystal’s intrinsic electric field, which is uniquely prescribed in any given material. In contrast, for ultracold atomic systems, the engineered ‘material parameters’ are tunable: a variety of synthetic spin–orbit couplings can be engineered on demand using laser fields. Here we outline the current experimental and theoretical status of spin–orbit coupling in ultracold atomic systems, discussing unique features that enable physics impossible in any other known setting.
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