A digitally controlled silicon quantum processing unit

TL;DR

This paper presents a scalable silicon-based quantum processing unit integrating custom cryogenic control, superconducting wiring, and high-density qubits, demonstrating significant performance improvements and error correction capabilities.

Contribution

It introduces a scalable quantum chip with integrated control and wiring, achieving high-performance qubits and implementing quantum error correction.

Findings

Demonstrated qubit performance improvements by an order of magnitude.

Implemented a distance-5 repetition code and an error-detecting code.

Validated system performance through detailed simulation comparisons.

Abstract

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.