A simple universal routing strategy for reducing the connectivity requirements of quantum LDPC codes

Fuente: arXiv
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Autores principales: Zhao, Guangqi, Yan, Fei, Ni, Xiaotong
Formato: Preprint
Publicado: 2025
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author Zhao, Guangqi
Yan, Fei
Ni, Xiaotong
author_facet Zhao, Guangqi
Yan, Fei
Ni, Xiaotong
contents Quantum low-density parity-check codes reduce quantum error correction overhead but require dense, long-range connectivity that challenges hardware implementation, particularly for superconducting processors. We address this problem by demonstrating that long-range connections can be reduced at the cost of increased syndrome extraction circuit depth. Our approach is based on the observation that X and Z ancilla qubits form short loops with data qubits - a property that holds for any quantum code. This enables implementing stabilizer measurement circuits by routing data qubit information through ancilla qubits when direct connections are unavailable. For bivariate bicycle codes, we remove up to 50% of long-range connections while approximately doubling the circuit depth, with the circuit-level distance remaining largely preserved. This method can also be applied to surface codes, achieving the same hexagonal connectivity requirement as McEwen et al. (Quantum 7, 1172 (2023)). Our routing approach for designing syndrome extraction circuits is applicable to diverse quantum codes, offering a practical pathway toward their implementation on hardware with connectivity constraints.
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publishDate 2025
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spellingShingle A simple universal routing strategy for reducing the connectivity requirements of quantum LDPC codes
Zhao, Guangqi
Yan, Fei
Ni, Xiaotong
Quantum Physics
Quantum low-density parity-check codes reduce quantum error correction overhead but require dense, long-range connectivity that challenges hardware implementation, particularly for superconducting processors. We address this problem by demonstrating that long-range connections can be reduced at the cost of increased syndrome extraction circuit depth. Our approach is based on the observation that X and Z ancilla qubits form short loops with data qubits - a property that holds for any quantum code. This enables implementing stabilizer measurement circuits by routing data qubit information through ancilla qubits when direct connections are unavailable. For bivariate bicycle codes, we remove up to 50% of long-range connections while approximately doubling the circuit depth, with the circuit-level distance remaining largely preserved. This method can also be applied to surface codes, achieving the same hexagonal connectivity requirement as McEwen et al. (Quantum 7, 1172 (2023)). Our routing approach for designing syndrome extraction circuits is applicable to diverse quantum codes, offering a practical pathway toward their implementation on hardware with connectivity constraints.
title A simple universal routing strategy for reducing the connectivity requirements of quantum LDPC codes
topic Quantum Physics
url https://arxiv.org/abs/2509.00850