Curator's Take
This research represents a crucial step toward practical quantum computing by demonstrating how silicon-based qubits can be integrated with the kind of sophisticated control electronics needed for large-scale systems. The team's achievement of controlling 18 exchange-only qubits using a custom cryogenic CMOS controller addresses one of the field's most pressing challenges: how to manage the complex wiring and control requirements as quantum processors scale up from dozens to thousands of qubits. What makes this particularly significant is their successful implementation of quantum error correction codes, showing that their approach can maintain the fidelity needed for fault-tolerant quantum computing. The combination of silicon's manufacturing advantages with demonstrated error correction capabilities suggests a promising pathway toward commercially viable quantum computers that could leverage existing semiconductor infrastructure.
— Mark Eatherly
Summary
Commercially-relevant quantum computers will require large numbers of high-performing qubits that can be manufactured, integrated, and controlled at scale. Silicon exchange-only (EO) qubits are a strong candidate modality due to their control-signal simplicity and compatibility with advanced semiconductor manufacturing, but questions remain around the achievability of sufficiently low noise and a scalable control and wiring solution. Here we introduce a quantum processing unit composed of a custom-designed cryogenic CMOS controller, a novel high-density superconducting ribbon cable, and a low-noise EO qubit device. The quantum chip features a three-rail array of 54 exchange-coupled quantum dots, configurable to host up to 18 EO qubits. We integrate and use these components to demonstrate qubit performance for both single-qubit and entangling operations that advances the EO state of the art by an order of magnitude. We further validate this system by implementing a distance-5 repetition code and a quantum error detecting code then make detailed comparisons with simulations. Our approach facilitates a utility-scale quantum computer with manageable operational and capital requirements.