Silicon spin qubits are a promising platform for building scalable quantum computers as they are compatible with the semiconductor manufacturing technologies used to produce today’s computer chips. However, they have an important weakness: silicon spin qubits typically lose accuracy when several qubits are under parallel control. To be useful, quantum computers will need to operate many qubits simultaneously without compromising the accuracy of their operations.

Now, in a study published in Nature Physics, researchers from the RIKEN Center for Emergent Matter Science and collaborators have addressed this challenge by achieving high-fidelity control of multiple silicon spin qubits operating in parallel. Using a five-qubit silicon array controlled through a single shared microwave line, they identified a key source of errors during the simultaneous operation of qubits and developed a way to mitigate its effects.

According to Leon Camenzind, a research scientist at RIKEN and co-first author who supervised the experiments, “This shows that high-fidelity control can be maintained even when several qubits are operated at the same time and represents an important step toward scaling up silicon-based quantum processors.”