Improved Decoding of Circuit Noise and Fragile Boundaries of Tailored Surface Codes

Realizing the full potential of quantum computation requires error correction (QEC), with most recent breakthrough demonstrations QEC using surface code. codes use multiple noisy physical qubits to encode information in fewer logical qubits, enabling identification errors through a decoding process. This process increases fidelity (or accuracy) making more reliable. However, fast (efficient run-time) decoders neglect important noise characteristics, thereby reducing their accuracy. In this work, we introduce that are both and accurate, can be used wide class including Our decoders, named belief-matching belief-find, exploit all unlock higher accuracy QEC. Using code threshold as performance metric, observe at 0.94% probability for our outperforming 0.82% standard minimum-weight perfect matching decoder. We also test theoretical case study tailored biased model. find lead much lower qubit overhead respect standard, square Surprisingly, well-below-threshold regime, rectangular becomes resource efficient than due previously unnoticed phenomenon call “fragile boundaries.” outperform other terms accuracy, better results current quantum-error-correction experiments opening up new areas studies.12 MoreReceived 8 June 2022Revised 5 2023Accepted 12 2023DOI:https://doi.org/10.1103/PhysRevX.13.031007Published by American Physical Society under Creative Commons Attribution 4.0 International license. Further distribution work must maintain attribution author(s) published article’s title, journal citation, DOI.Published SocietyPhysics Subject Headings (PhySH)Research AreasQuantum correctionSurface computingQuantum Information