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Bibliographic Details
Main Authors: Koßmann, Gereon, Zeiss, Julius A., Fawzi, Omar, Berta, Mario
Format: Preprint
Published: 2025
Subjects:
Online Access:https://arxiv.org/abs/2507.12326
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author Koßmann, Gereon
Zeiss, Julius A.
Fawzi, Omar
Berta, Mario
author_facet Koßmann, Gereon
Zeiss, Julius A.
Fawzi, Omar
Berta, Mario
contents We revisit the extendability-based semi-definite programming hierarchy introduced by Berta et al. [Mathematical Programming, 1 - 49 (2021)], which provides converging outer bounds on the optimal fidelity of approximate quantum error correction (AQEC). As our first contribution, we introduce a measurement-based rounding scheme that extracts inner sequences of certifiably good encoder-decoder pairs from this outer hierarchy. To address the computational complexity of evaluating fixed levels of the hierarchy, we investigate the use of symmetry-based dimension reduction. In particular, we combine noise symmetries - such as those present in multiple copies of the qubit depolarizing channel - with the permutational symmetry arising from the extendability of the optimization variable. This framework is illustrated through basic, but already challenging numerical examples that showcase its practical effectiveness. Our results contribute to narrowing the gap between theoretical developments in quantum information theory and their practical applications in the analysis of small-scale quantum error-correcting codes.
format Preprint
id arxiv_https___arxiv_org_abs_2507_12326
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle On approximate quantum error correction for symmetric noise
Koßmann, Gereon
Zeiss, Julius A.
Fawzi, Omar
Berta, Mario
Quantum Physics
We revisit the extendability-based semi-definite programming hierarchy introduced by Berta et al. [Mathematical Programming, 1 - 49 (2021)], which provides converging outer bounds on the optimal fidelity of approximate quantum error correction (AQEC). As our first contribution, we introduce a measurement-based rounding scheme that extracts inner sequences of certifiably good encoder-decoder pairs from this outer hierarchy. To address the computational complexity of evaluating fixed levels of the hierarchy, we investigate the use of symmetry-based dimension reduction. In particular, we combine noise symmetries - such as those present in multiple copies of the qubit depolarizing channel - with the permutational symmetry arising from the extendability of the optimization variable. This framework is illustrated through basic, but already challenging numerical examples that showcase its practical effectiveness. Our results contribute to narrowing the gap between theoretical developments in quantum information theory and their practical applications in the analysis of small-scale quantum error-correcting codes.
title On approximate quantum error correction for symmetric noise
topic Quantum Physics
url https://arxiv.org/abs/2507.12326