Performance analysis of multi-shot shadow estimation

Shadow estimation is an efficient method for predicting many observables of a quantum state with a statistical guarantee. In the multi-shot scenario, one performs projective measurement on the sequentially prepared state for $K$ times after the same unitary evolution, and repeats this procedure for...

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Main Authors: You Zhou, Qing Liu
Format: Article
Language:English
Published: Verein zur Förderung des Open Access Publizierens in den Quantenwissenschaften 2023-06-01
Series:Quantum
Online Access:https://quantum-journal.org/papers/q-2023-06-29-1044/pdf/
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author You Zhou
Qing Liu
author_facet You Zhou
Qing Liu
author_sort You Zhou
collection DOAJ
description Shadow estimation is an efficient method for predicting many observables of a quantum state with a statistical guarantee. In the multi-shot scenario, one performs projective measurement on the sequentially prepared state for $K$ times after the same unitary evolution, and repeats this procedure for $M$ rounds of random sampled unitary. As a result, there are $MK$ times measurements in total. Here we analyze the performance of shadow estimation in this multi-shot scenario, which is characterized by the variance of estimating the expectation value of some observable $O$. We find that in addition to the shadow-norm $\|O \|_{\mathrm{shadow}}$ introduced in \cite{huang2020predicting}, the variance is also related to another norm, and we denote it as the cross-shadow-norm $\|O \|_{\mathrm{Xshadow}}$. For both random Pauli and Clifford measurements, we analyze and show the upper bounds of $\|O \|_{\mathrm{Xshadow}}$. In particular, we figure out the exact variance formula for Pauli observable under random Pauli measurements. Our work gives theoretical guidance for the application of multi-shot shadow estimation.
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spelling doaj.art-355a15c3b5c04fbc812e1e145bae8ab62023-06-29T14:01:52ZengVerein zur Förderung des Open Access Publizierens in den QuantenwissenschaftenQuantum2521-327X2023-06-017104410.22331/q-2023-06-29-104410.22331/q-2023-06-29-1044Performance analysis of multi-shot shadow estimationYou ZhouQing LiuShadow estimation is an efficient method for predicting many observables of a quantum state with a statistical guarantee. In the multi-shot scenario, one performs projective measurement on the sequentially prepared state for $K$ times after the same unitary evolution, and repeats this procedure for $M$ rounds of random sampled unitary. As a result, there are $MK$ times measurements in total. Here we analyze the performance of shadow estimation in this multi-shot scenario, which is characterized by the variance of estimating the expectation value of some observable $O$. We find that in addition to the shadow-norm $\|O \|_{\mathrm{shadow}}$ introduced in \cite{huang2020predicting}, the variance is also related to another norm, and we denote it as the cross-shadow-norm $\|O \|_{\mathrm{Xshadow}}$. For both random Pauli and Clifford measurements, we analyze and show the upper bounds of $\|O \|_{\mathrm{Xshadow}}$. In particular, we figure out the exact variance formula for Pauli observable under random Pauli measurements. Our work gives theoretical guidance for the application of multi-shot shadow estimation.https://quantum-journal.org/papers/q-2023-06-29-1044/pdf/
spellingShingle You Zhou
Qing Liu
Performance analysis of multi-shot shadow estimation
Quantum
title Performance analysis of multi-shot shadow estimation
title_full Performance analysis of multi-shot shadow estimation
title_fullStr Performance analysis of multi-shot shadow estimation
title_full_unstemmed Performance analysis of multi-shot shadow estimation
title_short Performance analysis of multi-shot shadow estimation
title_sort performance analysis of multi shot shadow estimation
url https://quantum-journal.org/papers/q-2023-06-29-1044/pdf/
work_keys_str_mv AT youzhou performanceanalysisofmultishotshadowestimation
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