Harmonic trap resonance enhanced synthetic atomic spin-orbit coupling

The widely adopted scheme for synthetic atomic spin-orbit coupling (SOC) is based on the momentum sensitive Raman coupling [1], which is easily implemented in one spatial dimension. Recently, schemes based on pulsed or periodically modulating gradient magnetic field (GMF) were proposed [2,3] and the main characteristic features have subsequently been demonstrated [4,5]. The present work reports an experimental discovery and the associated theoretical understanding of tuning the SOC strength synthesized with GMF through the motional resonance of atomic center-of-mass in a harmonic trap. In some limits, we observe up to 10 times stronger SOC compared to the momentum impulse from GMF for atoms in free space. \\\\ 1. Y.-J. Lin, et al, Nature \textbf{471}, 83 (2011).\\ 2. Z.-F. Xu, et al, Phys. Rev. A \textbf{87}, 063634 (2013). \\ 3. B. M. Anderson, et al, Phys. Rev. Lett. \textbf{111}, 125301 (2013).\\ 4. X. Luo, et al, Scientific Reports \textbf{6}, 18983 (2016). \\ 5. G. Jotzu, et al, Phys. Rev. Lett. \textbf{115}, 073002 (2015).