Fujitsu and QuTech realize high-precision quantum gates

• Fujitsu and QuTech achieve a world-first sub-0.1% error probability in a complete universal quantum gate set for diamond spin qubits, exceeding the threshold for quantum error correction, an important step towards fault tolerant quantum computing and the practical application of quantum computers
• High-purity diamonds with reduced carbon-13 isotope concentration and advanced performance measurement techniques were used to achieve over 99.9% fidelity in both single- and two-qubit gate operations, minimizing environmental noise
• Future collaborations will focus on scaling up the system by increasing the number of qubits and developing advanced optical interconnects and control circuits

KAWASAKI, Japan, March 24, 2025 /PRNewswire/ -- Fujitsu Limited today announced the world's first demonstration of a complete universal quantum gate set for diamond spin qubits with an error probability below 0.1%, achieving a fidelity among the highest reported over all quantum hardware technologies. This collaboration with QuTech, a leading quantum technology research institute of Delft University of Technology, marks an important step for the diamond spin method towards carrying out quantum error correction and realizing practical quantum computing. The findings were published in Physical Review Applied on March 21,  2025.

The newly developed technology utilizes high-purity diamonds to create a stable two-qubit system comprising an electron spin and nitrogen nuclear spin within a nitrogen-vacancy center, a kind of atomic defect that can be harnessed for quantum computing. The team used advanced techniques to eliminate the impact of environmental noise on qubits and measure the performance of the quantum gates, achieving over 99.9% fidelity for both single- and two-qubit gates across a universal gate set. This surpasses the threshold required for quantum error correction.

Going forward, Fujitsu and QuTech will continue to collaborate, increasing the number of qubits used and developing optical quantum chips and control circuits to advance research toward the early practical application of diamond spin quantum computers.

Future Plans

Moving forward, Fujitsu and QuTech will focus on applying the newly developed technology to systems with a larger number of nuclear spins and developing technologies for high-precision optical interconnects between distant electron spin qubits to increase the number of manageable qubits. Furthermore, the team will accelerate research and development towards realizing a scalable quantum computing system, including integration technologies with control circuits using cryo-CMOS low temperature semiconductor integrated circuits.

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