A digitally controlled silicon quantum processing unit

Area of Science:

• Quantum Computing
• Semiconductor Devices
• Quantum Information Science

Background:

• Commercially viable quantum computers need scalable, high-performance qubits.
• Silicon exchange-only qubits offer manufacturing advantages but face noise and control challenges.
• Existing quantum systems struggle with large-scale integration and control.

Purpose of the Study:

• To introduce a novel quantum processing unit integrating a cryogenic CMOS controller, superconducting interconnects, and a low-noise exchange-only qubit device.
• To demonstrate enhanced qubit performance for single-qubit and entangling operations.
• To validate the system's potential for scalable quantum computation through quantum error correction code implementation.

Main Methods:

• Designed and fabricated a quantum chip with 54 exchange-coupled quantum dots, configurable into 18 exchange-only qubits.
• Integrated a custom cryogenic complementary metal-oxide-semiconductor (CMOS) controller and high-density superconducting ribbon cables.
• Performed single-qubit and entangling gate operations, and implemented distance-5 repetition and distance-2 quantum error-detecting codes.

Main Results:

• Achieved an order-of-magnitude improvement in exchange-only qubit performance compared to the state of the art.
• Demonstrated successful integration of the CMOS controller, interconnects, and qubit chip.
• Validated system performance through quantum error correction code implementation and comparison with simulations.

Conclusions:

• The developed quantum processing unit represents a significant step towards scalable quantum computing.
• The integrated system addresses key challenges in qubit performance, control, and manufacturing.
• This work paves the way for utility-scale quantum computers with reduced operational and capital costs.