Ion traps and cold atoms for quantum computers

Daniel F. V. James, Raymond Laflamme, Richard Hughes

D.F.V. James

Florian Sander

In order to scale up quantum computing, a scalable experimental architecture is needed, with the trapped-ion quantum computing platform; this has led to the implementation of surface ion traps. Despite being more performant than the older linear Paul trap design, they suffer from a lower trap depth. This reduces not only the probability of ion capture but also increases the dependency on the vacuum quality. Therefore, clean, cold, compact and robust atom sources are needed for the next generation of ion-trap-based quantum computers. Within the scope of this thesis, a repumped 3D magneto-optical trap (MOT) for the 40Ca species with a loading time of 1 s was demonstrated. Furthermore, we have also shown the ability to measure the performance of cold atom sources by resolving different Calcium isotopes via photoionisation detection. Finally, we demonstrate a novel and compact pyramid MOT design, which was tested and verified for 40Ca. The presented magneto-optical trap design can be integrated into other quantum computing experiments.

Hiroki Takahashi

Arne Härter, Johannes Hecker Denschlag

In the last five years, a novel field of physics and chemistry has developed in which cold trapped ions and ultracold atomic gases are brought into contact with each other. Combining ion traps with traps for neutral atoms yields a variety of new possibilities for research and experiments. These range from studies of cold atom–ion collisions and atom–ion chemistry to applications in quantum information science and condensed matter related research. In this article we give a brief introduction into this new field and describe some of the perspectives for its future development.

R. Blatt, Wolfgang Lange