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

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 re...

Full description

Bibliographic Details
Main Authors: Christopher Chamberland, Earl T. Campbell
Format: Article
Language:English
Published: American Physical Society 2022-05-01
Series:Physical Review Research
Online Access:http://doi.org/10.1103/PhysRevResearch.4.023090
_version_ 1797210710139207680
author Christopher Chamberland
Earl T. Campbell
author_facet Christopher Chamberland
Earl T. Campbell
author_sort Christopher Chamberland
collection DOAJ
description 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.
first_indexed 2024-04-24T10:14:55Z
format Article
id doaj.art-2cec969ab5634736b064c10252eb0e5a
institution Directory Open Access Journal
issn 2643-1564
language English
last_indexed 2024-04-24T10:14:55Z
publishDate 2022-05-01
publisher American Physical Society
record_format Article
series Physical Review Research
spelling doaj.art-2cec969ab5634736b064c10252eb0e5a2024-04-12T17:20:28ZengAmerican Physical SocietyPhysical Review Research2643-15642022-05-014202309010.1103/PhysRevResearch.4.023090Circuit-level protocol and analysis for twist-based lattice surgeryChristopher ChamberlandEarl T. CampbellLattice 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.http://doi.org/10.1103/PhysRevResearch.4.023090
spellingShingle Christopher Chamberland
Earl T. Campbell
Circuit-level protocol and analysis for twist-based lattice surgery
Physical Review Research
title Circuit-level protocol and analysis for twist-based lattice surgery
title_full Circuit-level protocol and analysis for twist-based lattice surgery
title_fullStr Circuit-level protocol and analysis for twist-based lattice surgery
title_full_unstemmed Circuit-level protocol and analysis for twist-based lattice surgery
title_short Circuit-level protocol and analysis for twist-based lattice surgery
title_sort circuit level protocol and analysis for twist based lattice surgery
url http://doi.org/10.1103/PhysRevResearch.4.023090
work_keys_str_mv AT christopherchamberland circuitlevelprotocolandanalysisfortwistbasedlatticesurgery
AT earltcampbell circuitlevelprotocolandanalysisfortwistbasedlatticesurgery