High-fidelity sub-microsecond single-shot electron spin readout above 3.5 K.

Area of Science:

• Quantum computing
• Semiconductor physics
• Quantum information science

Background:

• Electron spin qubits are promising for quantum computing due to their scalability and manufacturability.
• Current readout methods, while high-fidelity, are too slow for practical applications, limited by coherence times.
• Faster readout is essential for advancing quantum computation and error correction.

Purpose of the Study:

• To develop a faster and higher-temperature readout technique for electron spin qubits.
• To demonstrate latched parity readout with high fidelity and reduced integration time.
• To enable operation of quantum computing systems at higher, more practical temperatures.

Main Methods:

• Engineering the precise nanoscale location of multi-donor quantum dot qubits.
• Implementing latched parity readout for two-electron systems.
• Utilizing strong confinement potentials and engineered tunnel rates in donor qubits.

Main Results:

• Achieved latched parity readout in 175 ns with 99.44% fidelity at millikelvin temperatures.
• Demonstrated high-fidelity (97.87%) readout at 3.7 K, a significant temperature increase.
• Showcased a clear performance improvement in state preparation and measurement for donor spin qubits.

Conclusions:

• The developed latched parity readout significantly improves speed and temperature operation for electron spin qubits.
• This advancement brings the surface code implementation using semiconductor qubits closer to reality.
• The results pave the way for more robust and scalable quantum computing architectures.