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  • Open Access

Spin-qubit leapfrogging: Dynamics of shuttling electrons on top of another

Nicklas Meineke* and Guido Burkard†

  • *Contact author: nicklas.meineke@uni-konstanz.de
  • †Contact author: guido.burkard@uni-konstanz.de
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Phys. Rev. Research 8, 043043 – Published 14 October, 2026

DOI: https://doi.org/10.1103/l1vq-9zhr

Abstract

Spin shuttling has crystalized as a powerful and promising tool for establishing intermediate-range connectivity in semiconductor spin-qubit devices. Although experimental demonstrations have performed exceptionally well on different materials platforms, the question of how to handle areas of low valley splitting in silicon during shuttling remains unresolved. In this work, we explore the possibility of utilizing the valley degree of freedom, particularly in regions of low valley splitting, to allow mobile spin qubits to be shuttled through an occupied stationary quantum dot, thereby leapfrogging over the stationary electron. This not only grants a more enriched mobility for shuttled electrons, as it opens new possible routing paths, but also enables the implementation of an entangling swapγ two-qubit gate operation in the process. Simulating this process for different sets of parameters, we demonstrate the feasibility of such an operation and offer a unique use case for otherwise precarious regions of a quantum processor chip and propose a possible extension to the set of possible operations for silicon spin-qubit devices.

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Phys. Rev. Research 8, 043043– Published 14 October, 2026
  • Received 15 April 2026
  • Accepted 1 September 2026
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

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