Microwave-driven coherent operation of a semiconductor quantum dot charge qubit

Area of Science:

• Quantum computing
• Semiconductor physics

Background:

• Electron charge in double quantum dots serves as a qubit.
• Charge noise causes rapid dephasing, limiting qubit control.
• Previous DC voltage pulse methods lacked high fidelity due to sweet spot deviations.

Purpose of the Study:

• To achieve fast and universal single-qubit rotations.
• To demonstrate high-fidelity control of semiconductor charge qubits.
• To protect qubit operations from charge noise using resonant driving.

Main Methods:

• Utilized resonant AC microwave driving for qubit manipulation.
• Implemented fast (GHz) single qubit rotations.
• Employed standard process tomography and gate set tomography for characterization.

Main Results:

• Achieved fast and universal single qubit rotations.
• Demonstrated protection of Z-axis rotations and arbitrary X-Y plane rotations at the sweet spot.
• Process fidelities consistently exceeded 86% for universal single-qubit operations.

Conclusions:

• Resonant AC microwave driving enables high-fidelity control of semiconductor charge qubits.
• This method overcomes limitations of DC gating by operating at the sweet spot.
• The demonstrated technique offers a pathway for robust quantum information processing.