Efficient Shadow Tomography of Thermal States

Fuente: arXiv
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Hauptverfasser: Chen, Chi-Fang, Gilyén, András
Format: Preprint
Veröffentlicht: 2026
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author Chen, Chi-Fang
Gilyén, András
author_facet Chen, Chi-Fang
Gilyén, András
contents We present a general protocol for estimating $M$ observables from only $\mathcal{O}(\log (M)/\varepsilon^2)$ copies of a Gibbs state whose Hamiltonian is accessible. The protocol uses single-copy, nonadaptive measurements and uses a total Hamiltonian simulation time of $\widetilde{\mathcal{O}}(βM/\varepsilon^2)$; we show that the sample complexity is optimal in a black-box setting where exponential time Hamiltonian simulation is prohibited. The key idea is a new interpretation of quantum Gibbs samplers as \textit{detailed-balance measurement channels}: measurements that preserve the Gibbs state when outcomes are marginalized. Consequently, shadow tomography of thermal states admits a general efficient algorithm when the Hamiltonian is known, substantially lowering the readout cost in quantum thermal simulation.
format Preprint
id arxiv_https___arxiv_org_abs_2603_16845
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Efficient Shadow Tomography of Thermal States
Chen, Chi-Fang
Gilyén, András
Quantum Physics
We present a general protocol for estimating $M$ observables from only $\mathcal{O}(\log (M)/\varepsilon^2)$ copies of a Gibbs state whose Hamiltonian is accessible. The protocol uses single-copy, nonadaptive measurements and uses a total Hamiltonian simulation time of $\widetilde{\mathcal{O}}(βM/\varepsilon^2)$; we show that the sample complexity is optimal in a black-box setting where exponential time Hamiltonian simulation is prohibited. The key idea is a new interpretation of quantum Gibbs samplers as \textit{detailed-balance measurement channels}: measurements that preserve the Gibbs state when outcomes are marginalized. Consequently, shadow tomography of thermal states admits a general efficient algorithm when the Hamiltonian is known, substantially lowering the readout cost in quantum thermal simulation.
title Efficient Shadow Tomography of Thermal States
topic Quantum Physics
url https://arxiv.org/abs/2603.16845