High-fidelity spin qubit operation and algorithmic initialization above 1 K.

Area of Science:

• Quantum Computing
• Semiconductor Physics
• Quantum Information Science

Background:

• Semiconductor spin qubits offer a scalable path to quantum computers.
• High qubit counts generate thermal loads exceeding current cooling capacities.
• Fault-tolerant quantum operations are necessary above 1 Kelvin for scalability.

Purpose of the Study:

• To demonstrate high-fidelity operation of spin qubits in silicon at temperatures above 1 Kelvin.
• To overcome the limitation of thermal energy exceeding qubit energy for high-fidelity operations.
• To advance scalable and fault-tolerant quantum computation.

Main Methods:

• Tuning and operating spin qubits in silicon above 1 Kelvin.
• Developing an algorithmic initialization protocol for pure two-qubit states.
• Utilizing radiofrequency readout for qubit initialization and measurement.

Main Results:

• Achieved fidelities for readout and initialization up to 99.34%.
• Demonstrated single-qubit Clifford gate fidelities up to 99.85%.
• Attained a two-qubit gate fidelity of 98.92%.

Conclusions:

• High-fidelity spin qubit operation is possible above 1 Kelvin, overcoming a key scalability obstacle.
• The demonstrated techniques are crucial for enabling fault-tolerant quantum computation.
• This work significantly advances the development of large-scale, commercially viable quantum computers.