Universal control of a six-qubit quantum processor in silicon.

Area of Science:

• Quantum Computing
• Semiconductor Physics
• Quantum Information Science

Background:

• Scalable quantum computers require numerous qubits with high operational fidelity.
• Current quantum dot systems typically involve 1-4 qubits, optimizing specific operations.
• Achieving both high qubit count and fidelity remains a significant challenge.

Purpose of the Study:

• To design, fabricate, and operate a six-qubit processor.
• To achieve respectable fidelities for universal quantum operations, state preparation, and measurement.
• To overcome the conflict between large qubit counts and high fidelity.

Main Methods:

• Utilized semiconductor quantum dots as qubits.
• Employed careful Hamiltonian engineering for precise control.
• Implemented a high level of abstraction for quantum circuit programming.
• Developed efficient background calibration techniques.
• Integrated initialization by measurement with real-time feedback and quantum-non-demolition measurements for state preparation.

Main Results:

• Successfully operated a six-qubit processor.
• Achieved respectable fidelities for universal operations, state preparation, and measurement.
• Demonstrated simultaneous high qubit count and operational fidelity.

Conclusions:

• This work represents a major step towards large-scale quantum computing.
• The developed processor enables testing of more complex quantum protocols.
• Advances in qubit control and calibration are crucial for scaling quantum systems.