Quantum Codeword Sensing
Abstract
Consider the task of identifying an unknown classical codeword delivered to a register of quantum sensor qubits through a sequence of weak phase interactions that each encode one bit. Suppose that each received bit controls an identical Z-rotation of angle θ applied to every sensor qubit; receivers may also use auxiliary qubits within a total qubit budget Q, with arbitrary control unitaries and entanglement among all qubits allowed during each reception step. When the total collected signal is weak (Qθ→ 0), we establish that a sensor coupled to a persistent quantum memory can identify the original codeword more reliably than any receiver with the same Q and θ but only classical memory between received bits, even when bit flips occur during transmission. In particular, for a family of [n,k] binary simplex codes with even k and n=2k−1, we achieve exact correction of up to t≤(k−2)/4 transmission errors by coupling the sensor register to a persistent quantum memory of the same size, using Q = Θ((t+1)log n) and θ=2π/(k√(n+1)); for t=o(√k), every comparable receiver with only classical memory instead has average success probability (over uniformly chosen codewords) tending to zero. Furthermore, under independent bit flips of any fixed probability p<1/16, our receiver with persistent quantum memory achieves decoding error tending to zero as n→∞ using Q=O(log nloglog n) total qubits and the same θ. In contrast, every otherwise equivalent receiver with only classical memory has vanishing average success probability under the same stochastic error model.
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BibTeX
@misc{blue2026quantum,
title = {{Quantum Codeword Sensing}},
author = {John Blue and Zachary E. Chin and Vlad S. Oros and Isaac L. Chuang},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.03659},
eprint = {2610.03659},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.03659},
}
RIS
TY - UNPB
TI - Quantum Codeword Sensing
AU - John Blue
AU - Zachary E. Chin
AU - Vlad S. Oros
AU - Isaac L. Chuang
PY - 2026
DA - 2026/10/02
PB - arXiv
DO - 10.48550/arxiv.2610.03659
UR - https://arxiv.org/abs/2610.03659
AB - Consider the task of identifying an unknown classical codeword delivered to a register of quantum sensor qubits through a sequence of weak phase interactions that each encode one bit. Suppose that each received bit controls an identical Z-rotation of angle θ applied to every sensor qubit; receivers may also use auxiliary qubits within a total qubit budget Q, with arbitrary control unitaries and entanglement among all qubits allowed during each reception step. When the total collected signal is weak (Qθ→ 0), we establish that a sensor coupled to a persistent quantum memory can identify the original codeword more reliably than any receiver with the same Q and θ but only classical memory between received bits, even when bit flips occur during transmission. In particular, for a family of [n,k] binary simplex codes with even k and n=2^k−1, we achieve exact correction of up to t≤(k−2)/4 transmission errors by coupling the sensor register to a persistent quantum memory of the same size, using Q = Θ((t+1)log n) and θ=2π/(k√(n+1)); for t=o(√k), every comparable receiver with only classical memory instead has average success probability (over uniformly chosen codewords) tending to zero. Furthermore, under independent bit flips of any fixed probability p<1/16, our receiver with persistent quantum memory achieves decoding error tending to zero as n→∞ using Q=O(log nloglog n) total qubits and the same θ. In contrast, every otherwise equivalent receiver with only classical memory has vanishing average success probability under the same stochastic error model.
ER -