Fujitsu has 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 (TU Delft), marks an important step for the diamond spin method towards carrying out quantum error correction and realizing practical quantum computing.
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 (NV) center (2), 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.
Diamond spin technology utilizes the spins (electron and nuclear spins) formed by color centers – specific defects – within diamond crystals as qubits. Diamond spins can hold quantum states for relatively long periods of time, which makes them promising as high-performance qubits.
Their operational temperature is approximately 100x higher than that of superconducting qubits, making them easier to work with. The capability of diamond spin qubits to transmit quantum states using photons (fundamental particles of light) also allows for optical interconnects, providing a promising path towards scalable quantum computers and distributed computing via quantum networks.
