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  • Open Access

Runtime reduction in lattice surgery utilizing timelike soft information

Yutaro Akahoshi1,2,*,†, Riki Toshio1,2,*, Jun Fujisaki1,2, Hirotaka Oshima1,2, Shintaro Sato1,2, and Keisuke Fujii2,3,4,5

  • *These authors contributed equally to this work.
  • †Contact author: akahoshi.yutaro@fujitsu.com
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Phys. Rev. Research 8, 033085 – Published 21 July, 2026

DOI: https://doi.org/10.1103/wz3p-sgdq

Abstract

Runtime optimization of the quantum computing within a given computational resource is important to achieve practical quantum advantage. In this paper, we propose a runtime reduction protocol for the lattice surgery, which utilizes the soft information corresponding to the logical measurement error. Our proposal is a simple two-step protocol: operating the lattice surgery with the small number of syndrome-measurement cycles and reexecuting it with full syndrome-measurement cycles in cases where the timelike soft information suggests the presence of logical errors. We first discuss basic features of the timelike complementary gap as the concrete example of the timelike soft information based on numerical results. Then, we study average runtime of sequences of commutable logical Pauli measurements. We find that our protocol surpasses an existing runtime reduction protocol called temporally encoded lattice surgery (TELS) when the length of the sequence is small. In addition, we confirm that the combination of our protocol and the TELS protocol can reduce the runtime further, over 50% in comparison to the naive serial execution of the lattice surgery. The proposed protocol in this paper can be applied to any quantum computing architecture based on the lattice surgery, and we expect that this will be one of the fundamental building blocks of runtime optimization to achieve practical scale quantum computing.

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Outline

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Phys. Rev. Research 8, 033085– Published 21 July, 2026
  • Received 11 December 2025
  • Accepted 16 June 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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