A symmetric RF X-junction for register-based surface-electrode ion traps compatible with the near-field microwave approach

Register-based ion traps are among the leading approaches for scalable quantum processors. A fundamental component of these are junctions that allow the ions to be moved between the specialized zones of the quantum processor via ion transport. We discuss the design and optimization of such a junction and further present a symmetric RF X-junction with a shallow pseudopotential barrier and a substantial trap depth that is feasible for multilayer microfabrication. Furthermore, we present a transition zone making the symmetric RF X-junction compatible with an asymmetric RF near-field microwave gate-zone. Moreover, we present time-dependent transport voltages for reliable multi-zone and through-junction ion transport of a single 9Be+ ion.