Higgott, O;
Breuckmann, NP;
(2021)
Subsystem Codes with High Thresholds by Gauge Fixing and Reduced Qubit Overhead.
Physical Review X
, 11
(3)
, Article 031039. 10.1103/PhysRevX.11.031039.
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Abstract
We introduce a technique that uses gauge fixing to significantly improve the quantum-error-correcting performance of subsystem codes. By changing the order in which check operators are measured, valuable additional information can be gained, and we introduce a new method for decoding which uses this information to improve performance. Applied to the subsystem toric code with three-qubit check operators, we increase the threshold under circuit-level depolarizing noise from 0.67% to 0.81%. The threshold increases further under a circuit-level noise model with small finite bias, up to 2.22% for infinite bias. Furthermore, we construct families of finite-rate subsystem low-density parity-check codes with three-qubit check operators and optimal-depth parity-check measurement schedules. To the best of our knowledge, these finite-rate subsystem codes outperform all known codes at circuit-level depolarizing error rates as high as 0.2%, where they have a qubit overhead that is 4.3 × lower than the most efficient version of the surface code and 5.1 × lower than the subsystem toric code. Their threshold and pseudo-threshold exceeds 0.42% for circuit-level depolarizing noise, increasing to 2.4% under infinite bias using gauge fixing.
Type: | Article |
---|---|
Title: | Subsystem Codes with High Thresholds by Gauge Fixing and Reduced Qubit Overhead |
Open access status: | An open access version is available from UCL Discovery |
DOI: | 10.1103/PhysRevX.11.031039 |
Publisher version: | ttps://doi.org/10.1103/PhysRevX.11.031039 |
Language: | English |
Additional information: | 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. |
UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Computer Science |
URI: | https://discovery.ucl.ac.uk/id/eprint/10133813 |
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