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Operating semiconductor quantum processors with hopping spins

Affiliations
  • 1QuTech and Kavli Institute of Nanoscience, Delft University of Technology, 2600 GA Delft, Netherlands.
  • 2Department of Physics, University of Wisconsin-Madison, Madison, WI 53706, USA.
  • 3QuTech and Netherlands Organisation for Applied Scientific Research (TNO), 2628 CK Delft, Netherlands.

Published on:

July 25, 2024

Abstract

Qubits that can be efficiently controlled are essential for the development of scalable quantum hardware. Although resonant control is used to execute high-fidelity quantum gates, the scalability is challenged by the integration of high-frequency oscillating signals, qubit cross-talk, and heating. Here, we show that by engineering the hopping of spins between quantum dots with a site-dependent spin quantization axis, quantum control can be established with discrete signals. We demonstrate hopping-based quantum logic and obtain single-qubit gate fidelities of 99.97%, coherent shuttling fidelities of 99.992% per hop, and a two-qubit gate fidelity of 99.3%, corresponding to error rates that have been predicted to allow for quantum error correction. We also show that hopping spins constitute a tuning method by statistically mapping the coherence of a 10-quantum dot system. Our results show that dense quantum dot arrays with sparse occupation could be developed for efficient and high-connectivity qubit registers.

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