Ion traps
Ion-trap qubits are characterised by particularly long coherence times, high gate quality factors and high entanglement potential. This means they can be used to perform more complex calculations than qubits with shorter lifetimes and higher error rates. Furthermore, both their control systems and their integration into microelectronics and microfabrication are well-established. This makes them well-suited to industrial manufacturing. All of this makes ion traps an excellent basis for high-performance quantum computers. However, there are also hurdles: for instance, they must be cooled to very low temperatures and operated in a vacuum, and require complex control via numerous lasers. This currently still poses an obstacle to scalability. Furthermore, their characteristic stability has a downside: ion trap qubits switch comparatively slowly, which partially negates the advantage of long coherence times.
Significance for Germany
A vibrant, competitive environment has emerged in Germany centred on the production, classification and use of ion traps. Thanks to numerous research and development projects, as well as advances in applications, ion trap technology has progressed significantly. This applies in particular to quantum computing (ion traps are also suitable for other applications, such as extremely precise atomic clocks). Together with NV centres, they constitute the most widely used hardware platform amongst German start-ups and companies. Ion traps are therefore among the most promising systems in Germany.
Ion traps at the DLR QCI
We have commissioned no fewer than five ion trap projects with German and European industrial companies. The reason for this is that not only are ion traps technologically advanced, but the industrial ecosystem is also well-suited to this technology. In the first phase, we procured a 10-qubit demonstrator system. We awarded the second lot twice: the aim is to build and operate a quantum computer with at least 50 fully functional qubits on a single chip, which is scalable and, in the long term, capable of error correction. We are also awarding the third contract twice: as an alternative to the chip design from Contract 2, the focus here is on a modular design in which several chips are networked to form a scalable architecture.
To this end, through our Pilot Line in Hamburg, we offer ion trap companies state-of-the-art facilities in which to develop their intellectual property under secure conditions.
All ion trap projects at DLR QCI
Technical implementation
Ion traps capture individual ions in an electric field and cool them down to a few millikelvins using lasers. The qubits are realised through various energy states within the ion’s hyperfine structure. This enables extremely long coherence times. Gate operations are implemented either by targeted laser pulses or by global microwave and magnetic fields. The state of the qubits is ultimately measured via optical transitions. In recent years, there has been considerable progress in the miniaturisation of ion traps: this enables industrial manufacturing and innovative chip designs that contribute to scalability. We aim to further advance and utilise this knowledge through our research projects.
At our pilot line in Hamburg, we support ion-trap start-ups in the development and manufacture of ion-trap processors.
