Distant spin entanglement via fast and coherent electron shuttling

Area of Science:

• Quantum computing
• Semiconductor physics
• Quantum entanglement

Background:

• Networked quantum computers are crucial for achieving large-scale quantum computation.
• Current methods for electron spin qubits in semiconductors are limited to nearest-neighbor entanglement.
• On-chip long-distance entanglement is needed for versatile connections between quantum core units.

Purpose of the Study:

• To demonstrate controlled, coherent transfer of entangled electron spins between distant quantum dots on a chip.
• To investigate the preservation of quantum entanglement during spin transport.
• To explore the potential of surface acoustic waves for quantum interconnects.

Main Methods:

• Utilizing the moving trapping potential of surface acoustic waves to displace entangled electron spins.
• Employing quantum dots as trapping sites for electron spins.
• Observing spin quantum interferences to verify entanglement preservation.

Main Results:

• Successfully transferred a pair of entangled electron spins between two distant quantum dots.
• Maintained high-contrast quantum interference, indicating preserved entanglement over a 6 micrometer separation.
• Demonstrated coherent spin rotations induced by electron displacement.

Conclusions:

• Surface acoustic wave potentials enable controlled and coherent transfer of entangled electron spins.
• This technique preserves entanglement over significant on-chip distances.
• The method provides a pathway for fast, deterministic on-chip interconnection of remote quantum bits in semiconductor quantum circuits.