Building useful quantum registers requires reliable and scalable qubits—a major challenge in quantum technology. Diamond is a promising platform due to its nuclear spins that can keep their quantum state for minutes, but scaling beyond 20 qubits has been difficult. One approach is to link nitrogen-vacancy (NV) centers, which act as core qubits connecting clusters of nuclear spins. However, the low fidelity of two-qubit operations between NV electron spins has limited progress.
We address this bottleneck by identifying key error sources and achieving a record two-qubit fidelity of 96 %. This significant improvement makes it more feasible to scale up diamond-based systems.
Our results support diamond as a strong contender for larger-scale quantum computing. Unlike superconducting or ion-based systems, diamond qubits can operate at room temperature and integrate more easily into conventional data centers.
T. Joas, F. Ferlemann, R. Sailer,P.J. Vetter, J. Zhang, R. S. Said, T. Teraji, S. Onoda, T. Calarco, G. Genov,M. M. Müller, F. Jelezko
High-Fidelity Electron Spin Gates for Scaling Diamond Quantum Registers
Physical Review X 15, 021069
https://doi.org/10.1103/PhysRevX.15.021069