Far from Perfect: Quantum Error Correction with (Hyperinvariant) Evenbly Codes

We introduce a new class of qubit codes that we call Evenbly codes, building on a previous proposal of hyperinvariant tensor networks. Its tensor network description consists of local, non-perfect tensors describing CSS codes interspersed with Hadamard gates, placed on a hyperbolic $\{p,q\}$ geometr...

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Main Authors: Matthew Steinberg, Junyu Fan, Robert J. Harris, David Elkouss, Sebastian Feld, Alexander Jahn
Format: Article
Language:English
Published: Verein zur Förderung des Open Access Publizierens in den Quantenwissenschaften 2025-08-01
Series:Quantum
Online Access:https://quantum-journal.org/papers/q-2025-08-08-1826/pdf/
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author Matthew Steinberg
Junyu Fan
Robert J. Harris
David Elkouss
Sebastian Feld
Alexander Jahn
author_facet Matthew Steinberg
Junyu Fan
Robert J. Harris
David Elkouss
Sebastian Feld
Alexander Jahn
author_sort Matthew Steinberg
collection DOAJ
description We introduce a new class of qubit codes that we call Evenbly codes, building on a previous proposal of hyperinvariant tensor networks. Its tensor network description consists of local, non-perfect tensors describing CSS codes interspersed with Hadamard gates, placed on a hyperbolic $\{p,q\}$ geometry with even $q\geq 4$, yielding an infinitely large class of subsystem codes. We construct an example for a $\{5,4\}$ manifold and describe strategies of logical gauge fixing that lead to different rates $k/n$ and distances $d$, which we calculate analytically, finding distances which range from $d=2$ to $d \sim n^{2/3}$. Investigating threshold performance under erasure, depolarizing, and pure Pauli noise channels, we find that the code exhibits a depolarizing noise threshold of about 19.1% in the code-capacity model and 50% for pure Pauli and erasure channels under suitable gauges. We also test a constant-rate version with $k/n = 0.125$, finding excellent error resilience (about 40%) under the erasure channel. Recovery rates for these and other settings are studied both under an optimal decoder as well as a more efficient but non-optimal greedy decoder. We also consider generalizations beyond the CSS tensor construction, compute error rates and thresholds for other hyperbolic geometries, and discuss the relationship to holographic bulk/boundary dualities. Our work indicates that Evenbly codes may show promise for practical quantum computing applications.
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institution Kabale University
issn 2521-327X
language English
publishDate 2025-08-01
publisher Verein zur Förderung des Open Access Publizierens in den Quantenwissenschaften
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spelling doaj-art-720dd67d28f84888be2a5beb474a9add2025-08-20T03:59:36ZengVerein zur Förderung des Open Access Publizierens in den QuantenwissenschaftenQuantum2521-327X2025-08-019182610.22331/q-2025-08-08-182610.22331/q-2025-08-08-1826Far from Perfect: Quantum Error Correction with (Hyperinvariant) Evenbly CodesMatthew SteinbergJunyu FanRobert J. HarrisDavid ElkoussSebastian FeldAlexander JahnWe introduce a new class of qubit codes that we call Evenbly codes, building on a previous proposal of hyperinvariant tensor networks. Its tensor network description consists of local, non-perfect tensors describing CSS codes interspersed with Hadamard gates, placed on a hyperbolic $\{p,q\}$ geometry with even $q\geq 4$, yielding an infinitely large class of subsystem codes. We construct an example for a $\{5,4\}$ manifold and describe strategies of logical gauge fixing that lead to different rates $k/n$ and distances $d$, which we calculate analytically, finding distances which range from $d=2$ to $d \sim n^{2/3}$. Investigating threshold performance under erasure, depolarizing, and pure Pauli noise channels, we find that the code exhibits a depolarizing noise threshold of about 19.1% in the code-capacity model and 50% for pure Pauli and erasure channels under suitable gauges. We also test a constant-rate version with $k/n = 0.125$, finding excellent error resilience (about 40%) under the erasure channel. Recovery rates for these and other settings are studied both under an optimal decoder as well as a more efficient but non-optimal greedy decoder. We also consider generalizations beyond the CSS tensor construction, compute error rates and thresholds for other hyperbolic geometries, and discuss the relationship to holographic bulk/boundary dualities. Our work indicates that Evenbly codes may show promise for practical quantum computing applications.https://quantum-journal.org/papers/q-2025-08-08-1826/pdf/
spellingShingle Matthew Steinberg
Junyu Fan
Robert J. Harris
David Elkouss
Sebastian Feld
Alexander Jahn
Far from Perfect: Quantum Error Correction with (Hyperinvariant) Evenbly Codes
Quantum
title Far from Perfect: Quantum Error Correction with (Hyperinvariant) Evenbly Codes
title_full Far from Perfect: Quantum Error Correction with (Hyperinvariant) Evenbly Codes
title_fullStr Far from Perfect: Quantum Error Correction with (Hyperinvariant) Evenbly Codes
title_full_unstemmed Far from Perfect: Quantum Error Correction with (Hyperinvariant) Evenbly Codes
title_short Far from Perfect: Quantum Error Correction with (Hyperinvariant) Evenbly Codes
title_sort far from perfect quantum error correction with hyperinvariant evenbly codes
url https://quantum-journal.org/papers/q-2025-08-08-1826/pdf/
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