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Circuit-level protocol and analysis for twist-based lattice surgery

Chamberland, Christopher and Campbell, Earl T. (2022) Circuit-level protocol and analysis for twist-based lattice surgery. Physical Review Research, 4 (2). Art. No. 023090. ISSN 2643-1564. doi:10.1103/physrevresearch.4.023090.

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Lattice surgery is a measurement-based technique for performing fault-tolerant quantum computation in two dimensions. When using the surface code, the most general lattice surgery operations require lattice irregularities called twist defects. However, implementing twist-based lattice surgery may require additional resources, such as extra device connectivity, and could lower the threshold and overall performance for the surface code. Here we provide an explicit twist-based lattice surgery protocol and its requisite connectivity layout. We also provide new stabilizer measurement circuits for measuring twist defects which are compatible with our chosen gate scheduling. We undertake the first circuit-level error correction simulations during twist-based lattice surgery using a biased depolarizing noise model. Our results indicate a slight decrease in the threshold for timelike logical failures compared to lattice surgery protocols with no twist defects in the bulk. However, comfortably below threshold (i.e., with CNOT infidelities below 5 × 10⁻³), the performance degradation is mild and in fact preferable over proposed alternative twist-free schemes. Lastly, we provide an efficient scheme for measuring Y operators along boundaries of surface codes, which bypasses certain steps that were required in previous schemes.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Chamberland, Christopher0000-0003-3239-5783
Campbell, Earl T.0000-0002-3903-2734
Additional Information:© 2022 The Author(s). 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. (Received 28 January 2022; accepted 13 April 2022; published 2 May 2022)
Group:AWS Center for Quantum Computing, Institute for Quantum Information and Matter
Issue or Number:2
Record Number:CaltechAUTHORS:20220601-257648000
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:114982
Deposited By: George Porter
Deposited On:02 Jun 2022 19:33
Last Modified:02 Jun 2022 19:33

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