Minimal Clifford Shadow Estimation by Mutually Unbiased Bases

Fuente: arXiv
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Main Authors: Zhang, Qingyue, Liu, Qing, Zhou, You
Format: Preprint
Published: 2023
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_version_ 1866909177780109312
author Zhang, Qingyue
Liu, Qing
Zhou, You
author_facet Zhang, Qingyue
Liu, Qing
Zhou, You
contents Predicting properties of large-scale quantum systems is crucial for the development of quantum science and technology. Shadow estimation is an efficient method for this task based on randomized measurements, where many-qubit random Clifford circuits are used for estimating global properties like quantum fidelity. Here we introduce the minimal Clifford measurement (MCM) to reduce the number of possible random circuits to the minimum, while keeping the effective post-processing channel in shadow estimation. In particular, we show that MCM requires $2^n+1$ distinct Clifford circuits, and it can be realized by Mutually Unbiased Bases (MUB), with $n$ as the total qubit number. By applying the Z-Tableau formalism, this ensemble of circuits can be synthesized to the $\mathrm{-S-CZ-H-}$ structure, which can be composed by $2n-1$ fixed circuit modules, and the total circuit depth is at most $n+1$. Compared to the original Clifford measurements, our MCM significantly reduces the circuit complexity and the compilation costs. In addition, we find the sampling advantage of MCM on estimating off-diagonal operators, and extend this observation to the biased-MCM scheme to enhance the sampling improvement further.
format Preprint
id arxiv_https___arxiv_org_abs_2310_18749
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Minimal Clifford Shadow Estimation by Mutually Unbiased Bases
Zhang, Qingyue
Liu, Qing
Zhou, You
Quantum Physics
Predicting properties of large-scale quantum systems is crucial for the development of quantum science and technology. Shadow estimation is an efficient method for this task based on randomized measurements, where many-qubit random Clifford circuits are used for estimating global properties like quantum fidelity. Here we introduce the minimal Clifford measurement (MCM) to reduce the number of possible random circuits to the minimum, while keeping the effective post-processing channel in shadow estimation. In particular, we show that MCM requires $2^n+1$ distinct Clifford circuits, and it can be realized by Mutually Unbiased Bases (MUB), with $n$ as the total qubit number. By applying the Z-Tableau formalism, this ensemble of circuits can be synthesized to the $\mathrm{-S-CZ-H-}$ structure, which can be composed by $2n-1$ fixed circuit modules, and the total circuit depth is at most $n+1$. Compared to the original Clifford measurements, our MCM significantly reduces the circuit complexity and the compilation costs. In addition, we find the sampling advantage of MCM on estimating off-diagonal operators, and extend this observation to the biased-MCM scheme to enhance the sampling improvement further.
title Minimal Clifford Shadow Estimation by Mutually Unbiased Bases
topic Quantum Physics
url https://arxiv.org/abs/2310.18749