Distant spin entanglement via fast and coherent electron shuttling

Abstract

In the quest for large-scale quantum computing, networked quantum computers offer a natural path towards scalability. While recent experiments have demonstrated nearest neighbour entanglement for electron spin qubits in semiconductors, on-chip long-distance entanglement could bring more versatility to connect quantum core units. Here, we employ the moving trapping potential of a surface acoustic wave to realize the controlled and coherent transfer of a pair of entangled electron spins between two distant quantum dots. The subsequent electron displacement induces coherent spin rotations, which drives spin quantum interferences. We observe high-contrast interference as a signature of the preservation of the entanglement all along the displacement procedure, which includes a separation of the two spins by a distance of 6\u2009μm. This work opens the route towards fast on-chip deterministic interconnection of remote quantum bits in semiconductor quantum circuits. On-chip, long-distance entanglement of spin qubits in semiconductors could enable connectivity of quantum core units for networked quantum computing. The moving trapping potential of a surface acoustic wave can subsequently displace two entangled spins while preserving entanglement over a separation of 6\u2009μm.