Achieving the Heisenberg limit using fault-tolerant quantum error correction

Fuente: arXiv
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Main Authors: Sahu, Himanshu, Xu, Qian, Zhou, Sisi
Format: Preprint
Published: 2026
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author Sahu, Himanshu
Xu, Qian
Zhou, Sisi
author_facet Sahu, Himanshu
Xu, Qian
Zhou, Sisi
contents Quantum effect enables enhanced estimation precision in metrology, with the Heisenberg limit (HL) representing the ultimate limit allowed by quantum mechanics. Although the HL is generally unattainable in the presence of noise, quantum error correction (QEC) can recover the HL in various scenarios. A notable example is estimating a Pauli-$Z$ signal under bit-flip noise using the repetition code, which is both optimal for metrology and robust against noise. However, previous protocols often assume noise affects only the signal accumulation step, while the QEC operations -- including state preparation and measurement -- are noiseless. To overcome this limitation, we study fault-tolerant quantum metrology where all qubit operations are subject to noise. We focus on estimating a Pauli-$Z$ signal under bit-flip noise, together with state preparation and measurement errors in all QEC operations. We propose a fault-tolerant metrological protocol where a repetition code is prepared via repeated syndrome measurements, followed by a fault-tolerant logical measurement. We demonstrate the existence of an error threshold, below which errors are effectively suppressed and the HL is attained.
format Preprint
id arxiv_https___arxiv_org_abs_2601_05457
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Achieving the Heisenberg limit using fault-tolerant quantum error correction
Sahu, Himanshu
Xu, Qian
Zhou, Sisi
Quantum Physics
Quantum effect enables enhanced estimation precision in metrology, with the Heisenberg limit (HL) representing the ultimate limit allowed by quantum mechanics. Although the HL is generally unattainable in the presence of noise, quantum error correction (QEC) can recover the HL in various scenarios. A notable example is estimating a Pauli-$Z$ signal under bit-flip noise using the repetition code, which is both optimal for metrology and robust against noise. However, previous protocols often assume noise affects only the signal accumulation step, while the QEC operations -- including state preparation and measurement -- are noiseless. To overcome this limitation, we study fault-tolerant quantum metrology where all qubit operations are subject to noise. We focus on estimating a Pauli-$Z$ signal under bit-flip noise, together with state preparation and measurement errors in all QEC operations. We propose a fault-tolerant metrological protocol where a repetition code is prepared via repeated syndrome measurements, followed by a fault-tolerant logical measurement. We demonstrate the existence of an error threshold, below which errors are effectively suppressed and the HL is attained.
title Achieving the Heisenberg limit using fault-tolerant quantum error correction
topic Quantum Physics
url https://arxiv.org/abs/2601.05457