Coherent spin qubit shuttling through germanium quantum dots

TL;DR

This paper demonstrates the coherent shuttling of hole spin qubits in germanium quantum dots over significant distances, preserving quantum information and enabling quantum links within registers.

Contribution

It shows for the first time that hole spin qubits in germanium can be coherently shuttled over hundreds of micrometers, overcoming challenges posed by strong spin-orbit interaction.

Findings

Spin qubits shuttled over 300 μm while preserving quantum information.

Coherent superposition states shuttled over 9 μm, extendable to 49 μm with dynamical decoupling.

Qubit shuttling demonstrated as a viable method for routing within quantum registers.

Abstract

Quantum links can interconnect qubit registers and are therefore essential in networked quantum computing. Semiconductor quantum dot qubits have seen significant progress in the high-fidelity operation of small qubit registers but establishing a compelling quantum link remains a challenge. Here, we show that a spin qubit can be shuttled through multiple quantum dots while preserving its quantum information. Remarkably, we achieve these results using hole spin qubits in germanium, despite the presence of strong spin-orbit interaction. We accomplish the shuttling of spin basis states over effective lengths beyond 300 $\mu$m and demonstrate the coherent shuttling of superposition states over effective lengths corresponding to 9 $\mu$m, which we can extend to 49 $\mu$m by incorporating dynamical decoupling. These findings indicate qubit shuttling as an effective approach to route qubits within registers and to establish quantum links between registers.