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We theoretically explore a Rashba spin–orbit coupling scheme which operates entirely in the absolute ground state manifold of an alkali atom, thereby minimizing all inelastic processes. An energy gap between ground eigenstates of the proposed coupling can be continuously opened or closed by modifying laser polarizations. Our technique uses far-detuned ‘Raman’ laser coupling to create the Rashba potential, which has the benefit of low spontaneous emission rates. At these detunings, the Raman matrix elements that link m _F magnetic sublevel quantum numbers separated by two are also suppressed. These matrix elements are necessary to produce the Rashba Hamiltonian within a single total angular momentum f manifold. However, the far-detuned Raman couplings can link the three XYZ states familiar to quantum chemistry, which possess the necessary connectivity to realize the Rashba potential. We show that these XYZ states are essentially the hyperfine spin eigenstates of ${}^{87}\mathrm{Rb}$ dressed by a strong radio-frequency magnetic field.

We observed a new mechanism for vortex nucleation in Bose–Einstein condensates (BECs) subject to synthetic magnetic fields. We made use of a strong synthetic magnetic field initially localized between a pair of merging BECs to rapidly create vortices in the bulk of the merged condensate. Unlike previous implementations and in agreement with our Gross–Pitaevskii equation simulations, our dynamical process rapidly injects vortices into our system’s bulk, and with initial number in excess of the system’s equilibrium vortex number.

Phases of matter are characterized by order parameters describing the type and degree of order in a system. Here, the authors explore the magnetic phases and the phase transitions present in a near-zero temperature spin-1 spin-orbit-coupled Bose gas, observing ferromagnetic and unpolarized states.