Trapped-ion spin-motion coupling with microwaves and a near-motional oscillating magnetic field gradient

\noindent We present a new method of spin-motion coupling for trapped ions using microwaves and a magnetic field gradient oscillating close to the ions' motional frequency. We demonstrate and characterize this coupling experimentally in a surface-electrode trap that incorporates current-carrying electrodes to generate the microwave field and the oscillating magnetic field gradient. Using this method, we perform resolved-sideband cooling of a single motional mode to its ground state [1]. We also perform entangling gates between two ions and present initial results on gate fidelity.\\ \noindent [1] R. Srinivas \textit{et al.} arXiv:1812.02098 (2018)