Progress in the development of quantum computing hardware from diamond-based spin photon qubits

The consortium of the project SPINNING — Quantum Computers based on Spin Qubits in Diamond met at the Fraunhofer Institute for Applied Solid State Physics IAF on July 5 and 6, 2023. In this third project meeting, the partners presented the results in their fields of work, showing that the subprojects are on a very good track. The approach taken in SPINNING is characterized by quantum computing hardware having lower cooling requirements, longer operation times, and smaller error rates than other qubit technologies due to the special material properties of diamond. The consortium consists of 28 partners, including universities, research institutions, startups and medium-sized companies.

Close collaboration for spin-photon-based quantum computers

“The milestone meeting of the ‘SPINNING’ consortium showed that a very close collaboration has developed between all partners. Thus, we have created a promising foundation to jointly master the major challenges in the development of a quantum processor based on spin photons,” summarizes Dr. Peter Knittel, Deputy Head of Business Unit Quantum Systems at Fraunhofer IAF.“ The presented results make us optimistic that we will be able to achieve our project goal and demonstrate a scalable architecture for quantum processors based on spin qubits,” explains Prof. Dr. Rüdiger Quay, project coordinator and acting institute director of Fraunhofer IAF.

Interim results of the subprojects: Quantum computing hardware and software

In the area of hardware development, several designs for resonators and waveguide structures in diamond were successfully manufactured, enabling the timely integration of color centers into the resonators. The demonstration of color centers in silicon carbide (SiC) waveguides with selective control of 5 qubits as register was mastered for the first time. Regarding the infrastructure, several cryostats were commissioned, which are essential for the final demonstrator. They are also necessary to characterize the coupled quantum registers. In addition, a room temperature test system for spin qubits was implemented and the processor design for a 2-qubit register was finalized.

On the software side, hardware-independent benchmarks could be defined through using a digital twin, among others. The benchmarks allow the quantum processors and the error correction algorithms to be tested, first virtually and later on real hardware. Furthermore, a software stack for the optimal control of 1-, 2- as well as 3-qubit gates was realized and an interface to the software stack of the partner Quantum Brilliance was created.

Fraunhofer IAF coordinates SPINNING consortium

Fraunhofer IAF leads the consortium and also contributes its research infrastructure and capabilities in epitaxy of high-purity diamond and processing of quantum registers and processors to the project network. The German Federal Ministry of Education and Research (BMBF) is funding SPINNING over a period of three years.