Interplay of Zeeman Splitting and Tunnel Coupling in Coherent Spin Qubit Shuttling

TL;DR

This paper demonstrates high-fidelity spin shuttling in silicon quantum dots, revealing how tunnel coupling and Zeeman splitting influence error rates, and provides a model for optimizing quantum processor connectivity.

Contribution

It introduces a high-fidelity spin shuttling method in silicon MOS devices and analyzes the impact of tunnel coupling and Zeeman splitting on error rates.

Findings

Achieved 99.8% shuttling fidelity.

Error rate varies 20-fold with parameter tuning.

A four-level Hamiltonian model explains the results.

Abstract

Spin shuttling offers a promising approach for developing scalable silicon-based quantum processors by addressing the connectivity limitations of quantum dots. In this work, we demonstrate high-fidelity bucket-brigade spin shuttling in a silicon MOS device, utilizing Pauli-spin-blockade readout. We achieve an average shuttling fidelity of \SI{99.8}{\percent}. The residual shuttling error is highly sensitive to the ratio between interdot tunnel coupling and Zeeman splitting, with tuning of these parameters enabling up to a 20-fold variation in error rate. An appropriate four-level Hamiltonian model supports our findings. These results provide valuable insights for optimizing high-performance spin-shuttling systems in future quantum architectures.