High-fidelity single-spin shuttling in silicon

Area of Science:

• Quantum Computing
• Semiconductor Physics
• Materials Science

Background:

• Quantum processor performance relies heavily on qubit connectivity.
• High-fidelity electron transport in semiconductor spin qubits is crucial for scalability.
• Existing electron shuttling methods face challenges in maintaining spin coherence over distance.

Purpose of the Study:

• To demonstrate high-fidelity electron shuttling in semiconductor quantum dots.
• To investigate methods for increasing qubit connectivity through physical displacement.
• To improve spin coherence during electron transport for quantum information processing.

Main Methods:

• Electron shuttling experiments using electric gate potentials in isotopically purified Si/SiGe heterostructures.
• Comparison of bucket-brigade shuttling with conveyor-mode shuttling using travelling-wave potentials.
• Measurement of spin coherence decay and fidelity during electron transport over extended distances.

Main Results:

• Conveyor-mode shuttling achieved spin coherence an order of magnitude better than bucket-brigade shuttling.
• Electrons were displaced over an effective distance of 10 μm in under 200 ns.
• Preservation of the electron spin state with an average fidelity of 99.5% was achieved.

Conclusions:

• Electron shuttling is a viable technique for enhancing connectivity in semiconductor quantum processors.
• The developed conveyor-mode shuttling method significantly improves spin coherence and fidelity.
• These findings provide a pathway for realizing large-scale quantum processors utilizing electron shuttling within and between qubit arrays.