Pauli Measurements Are Near-Optimal for Single-Qubit Tomography

Fuente: arXiv
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Hauptverfasser: Acharya, Jayadev, Dharmavarapu, Abhilash, Liu, Yuhan, Yu, Nengkun
Format: Preprint
Veröffentlicht: 2025
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author Acharya, Jayadev
Dharmavarapu, Abhilash
Liu, Yuhan
Yu, Nengkun
author_facet Acharya, Jayadev
Dharmavarapu, Abhilash
Liu, Yuhan
Yu, Nengkun
contents We provide the first non-trivial lower bounds for single-qubit tomography algorithms and show that at least $Ω\left(\frac{10^N}{\sqrt{N} \varepsilon^2}\right)$ copies are required to learn an $N$-qubit state $ρ\in\mathbb{C}^{d\times d},d=2^N$ to within $\varepsilon$ trace distance. Pauli measurements, the most commonly used single-qubit measurement scheme, have recently been shown to require at most $O\left(\frac{10^N}{\varepsilon^2}\right)$ copies for this problem. Combining these results, we nearly settle the long-standing question of the complexity of single-qubit tomography.
format Preprint
id arxiv_https___arxiv_org_abs_2507_22001
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Pauli Measurements Are Near-Optimal for Single-Qubit Tomography
Acharya, Jayadev
Dharmavarapu, Abhilash
Liu, Yuhan
Yu, Nengkun
Quantum Physics
Computational Complexity
We provide the first non-trivial lower bounds for single-qubit tomography algorithms and show that at least $Ω\left(\frac{10^N}{\sqrt{N} \varepsilon^2}\right)$ copies are required to learn an $N$-qubit state $ρ\in\mathbb{C}^{d\times d},d=2^N$ to within $\varepsilon$ trace distance. Pauli measurements, the most commonly used single-qubit measurement scheme, have recently been shown to require at most $O\left(\frac{10^N}{\varepsilon^2}\right)$ copies for this problem. Combining these results, we nearly settle the long-standing question of the complexity of single-qubit tomography.
title Pauli Measurements Are Near-Optimal for Single-Qubit Tomography
topic Quantum Physics
Computational Complexity
url https://arxiv.org/abs/2507.22001