Qubit-oscillator concatenated codes: decoding formalism & code comparison

Published

June 14, 2023

Author(s)

Yijia Xu, Yixu Wang, En-Jui Kuo, Victor Albert

Abstract

Concatenating bosonic error-correcting codes with qubit codes can substantially boost the error-correcting power of the original qubit codes. It is not clear how to concatenate optimally, given there are several bosonic codes and concatenation schemes to choose from, including the recently discovered GKP-stabilizer codes [arXiv:1903.12615] that allow protection of a logical bosonic mode from fluctuations of the mode's conjugate variables. We develop efficient maximum-likelihood decoders for and analyze the performance of three different concatenations of codes taken from the following set: qubit stabilizer codes, analog/Gaussian stabilizer codes, GKP codes, and GKP-stabilizer codes. We benchmark decoder performance against additive Gaussian white noise, corroborating our numerics with analytical calculations. We observe that the concatenation involving GKP-stabilizer codes outperforms the more conventional concatenation of a qubit stabilizer code with a GKP code in some cases. We also propose a GKP-stabilizer code that suppresses fluctuations in both conjugate variables without squeezing resources, and formulate qudit versions of GKP-stabilizer codes.

Citation

arxiv.org

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http://www.arxiv.org

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https://doi.org/10.1103/PRXQuantum.4.020342

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Citation

Xu, Y. , Wang, Y. , Kuo, E. and Albert, V. (2023), Qubit-oscillator concatenated codes: decoding formalism & code comparison, arxiv.org, [online], https://doi.org/10.1103/PRXQuantum.4.020342, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=935509, http://www.arxiv.org (Accessed October 17, 2025)