Spin-EPR-pair separation by conveyor-mode single electron shuttling in Si/SiGe

Area of Science:

• Quantum Computing
• Quantum Information Science
• Solid-State Physics

Background:

• Scalable quantum computing requires robust qubit coupling mechanisms.
• Spin qubits offer a promising platform for quantum computation in silicon.
• Existing methods lack efficient long-range coherent coupling for scaling.

Purpose of the Study:

• To investigate spin coherence during conveyor-mode electron shuttling.
• To assess the feasibility of conveyor-mode shuttling for scalable quantum computing architectures.
• To quantify spin-shuttle infidelity and entanglement preservation over extended distances.

Main Methods:

• Utilized conveyor-mode electron shuttling to transport an Einstein-Podolsky-Rosen (EPR) spin-pair.
• Increased shuttle velocity by 10,000 times compared to previous studies.
• Measured spin coherence and entanglement fidelity after shuttling over distances up to 3.36 μm.

Main Results:

• Observed increased spin-qubit dephasing time with longer shuttle distances due to motional narrowing.
• Estimated spin-shuttle infidelity due to dephasing at 0.7% for a 560 nm shuttle distance.
• Detected spin entanglement of the EPR pair after shuttling through multiple loops (3.36 μm accumulated distance).

Conclusions:

• Conveyor-mode electron shuttling maintains spin coherence and entanglement over significant distances.
• This technique is compatible with industrial fabrication and requires minimal control terminals.
• Spin shuttling presents a viable pathway for building scalable, sparse qubit architectures in silicon.