Architecture for a scalable ion-trap quantum computer

A scalable architecture for quantum information processing with trapped ions depends, among other things, on the ability to store and manipulate large numbers of ions within a single processing unit, i.e. the ion trap. To reliably control the ions these traps must be stable and well characterised. Furthermore, reliable ways of sharing the information between the ions have to be developed. This work presents the development of and the results from two segmented-trap experiments. First, the ions are used as electrical field probes which serves as the basis for a novel diagnostic tool. With these probes light-induced charging of trap structures was observed with a sensitivity of 40 elementary charges per root Hz. Second, a way to share quantum information in a multiplexed trap structure by direct coupling between two trapping sites is presented. A coherent exchange of the motional states between two ions, separated by 54 microns, was observed. The coupling strength between these two trap sites was increased using additional ions as near-field antennae. (author)