Transport of multispecies ion crystals through a junction in an RF Paul trap

We report on the first demonstration of transport of a multispecies ion crystal through a junction in an RF Paul trap. The trap is a two-dimensional surface-electrode trap with an X junction and segmented control electrodes to which time-varying voltages are applied to control the shape and position of potential wells above the trap surface. We transport either a single \(^{171}\)Yb\(^+\) ion or a crystal composed of a \(^{138}\)Ba\(^+\) ion cotrapped with the \(^{171}\)Yb\(^+\) ion to any port of the junction. We characterize the motional excitation by performing multiple round-trips through the junction and back to the initial well position without cooling. The final excitation is then measured using sideband asymmetry. For a single \(^{171}\)Yb\(^+\) ion, transport with a \(4\;\mathrm{m/s}\) average speed induces between \(0.013\pm0.001\) and \(0.014\pm0.001\) quanta of excitation per round trip, depending on the exit port. For a Ba-Yb crystal, transport at the same speed induces between \(0.013\pm0.001\) and \(0.030\pm0.002\) quanta per round trip of excitation to the axial center of mass mode. Excitation in the axial stretch mode ranges from \(0.005\pm0.001\) to \(0.021\pm0.001\) quanta per round trip.