A digitally controlled silicon quantum processing unit

Commercially relevant quantum computers will require large numbers of high-performing qubits that can be manufactured, integrated and controlled at scale. Silicon exchange-only qubits 1–10 are a strong candidate modality owing to their control-signal simplicity and compatibility with advanced semiconductor manufacturing 11–13 , but questions remain around the achievability of sufficiently low noise and a scalable control and wiring solution 13–19 . Here we introduce a quantum processing unit composed of a custom-designed cryogenic complementary metal–oxide–semiconductor (CMOS) controller, a high-density superconducting ribbon cable and a low-noise exchange-only qubit device. The quantum chip features a 3-rail array of 54 exchange-coupled quantum dots, configurable to host up to 18 exchange-only qubits. We integrate and use these components to demonstrate qubit performance for both single-qubit and entangling operations that advances the exchange-only state of the art 7,8,10 by an order of magnitude. We further validate this system by implementing a distance-5 repetition code 20 and a distance-2 quantum error-detecting code 21–26 and then make detailed comparisons with simulations. Our work facilitates the development of future utility-scale quantum computers with manageable operational and capital requirements.