Benchmarking the Planar Honeycomb Code

Craig Gidney; Michael Newman; Matt McEwen

doi:10.22331/q-2022-09-21-813

Benchmarking the Planar Honeycomb Code

Craig Gidney¹, Michael Newman¹, and Matt McEwen^1,2

¹Google Quantum AI, Santa Barbara, California 93117, USA
²University of California, Santa Barbara, 93106, USA

Published:	2022-09-21, volume 6, page 813
Eprint:	arXiv:2202.11845v3
Doi:	https://doi.org/10.22331/q-2022-09-21-813
Citation:	Quantum 6, 813 (2022).

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Abstract

We improve the planar honeycomb code by describing boundaries that need no additional physical connectivity, and by optimizing the shape of the qubit patch. We then benchmark the code using Monte Carlo sampling to estimate logical error rates and derive metrics including thresholds, lambdas, and teraquop qubit counts. We determine that the planar honeycomb code can create a logical qubit with one-in-a-trillion logical error rates using 7000 physical qubits at a 0.1% gate-level error rate (or 900 physical qubits given native two-qubit parity measurements). Our results cement the honeycomb code as a promising candidate for two-dimensional qubit architectures with sparse connectivity.

Featured image: The cycle of measurements that defines the planar honeycomb code, and the locations of logical observables throughout this cycle. Uses XYZ=RGB color coding to map Pauli operators to colors.

Estimating overheads for quantum fault-tolerance in the honeycomb code (Talk by Mike Newman)

A short history of the honeycomb code (Talk by Craig Gidney)

Popular summary

In this paper, we benchmarked a new version of the honeycomb code. The old version of the honeycomb code couldn't fit on a flat surface. It had to be wrapped around a donut. That was a problem because many quantum computer architectures place qubits on a flat surface, not on donuts. Although the donut problem was fixed, the fix required changes that we were worried might seriously hurt the performance of the honeycomb code. However, the result of this paper is that the new honeycomb code still performs very well. This shows the honeycomb code is a viable error correcting code candidate for large scale quantum computer architectures, even ones that place qubits on a flat surface.

► BibTeX data

@article{Gidney2022benchmarkingplanar,
  doi = {10.22331/q-2022-09-21-813},
  url = {https://doi.org/10.22331/q-2022-09-21-813},
  title = {Benchmarking the {P}lanar {H}oneycomb {C}ode},
  author = {Gidney, Craig and Newman, Michael and McEwen, Matt},
  journal = {{Quantum}},
  issn = {2521-327X},
  publisher = {{Verein zur F{\"{o}}rderung des Open Access Publizierens in den Quantenwissenschaften}},
  volume = {6},
  pages = {813},
  month = sep,
  year = {2022}
}

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