Evaluating a quantum-classical quantum Monte Carlo algorithm with Matchgate shadows

Fuente: arXiv
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Main Authors: Huang, Benchen, Chen, Yi-Ting, Gupt, Brajesh, Suchara, Martin, Tran, Anh, McArdle, Sam, Galli, Giulia
Format: Preprint
Published: 2024
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author Huang, Benchen
Chen, Yi-Ting
Gupt, Brajesh
Suchara, Martin
Tran, Anh
McArdle, Sam
Galli, Giulia
author_facet Huang, Benchen
Chen, Yi-Ting
Gupt, Brajesh
Suchara, Martin
Tran, Anh
McArdle, Sam
Galli, Giulia
contents Solving the electronic structure problem of molecules and solids to high accuracy is a major challenge in quantum chemistry and condensed matter physics. The rapid emergence and development of quantum computers offer a promising route to systematically tackle this problem. Recent work by Huggins et al.[1] proposed a hybrid quantum-classical quantum Monte Carlo (QC-QMC) algorithm using Clifford shadows to determine the ground state of a Fermionic Hamiltonian. This approach displayed inherent noise resilience and the potential for improved accuracy compared to its purely classical counterpart. Nevertheless, the use of Clifford shadows introduces an exponentially scaling post-processing cost. In this work, we investigate an improved QC-QMC scheme utilizing the recently developed Matchgate shadows technique [2], which removes the aforementioned exponential bottleneck. We observe from experiments on quantum hardware that the use of Matchgate shadows in QC-QMC is inherently noise robust. We show that this noise resilience has a more subtle origin than in the case of Clifford shadows. Nevertheless, we find that classical post-processing, while asymptotically efficient, requires hours of runtime on thousands of classical CPUs for even the smallest chemical systems, presenting a major challenge to the scalability of the algorithm.
format Preprint
id arxiv_https___arxiv_org_abs_2404_18303
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Evaluating a quantum-classical quantum Monte Carlo algorithm with Matchgate shadows
Huang, Benchen
Chen, Yi-Ting
Gupt, Brajesh
Suchara, Martin
Tran, Anh
McArdle, Sam
Galli, Giulia
Quantum Physics
Chemical Physics
Solving the electronic structure problem of molecules and solids to high accuracy is a major challenge in quantum chemistry and condensed matter physics. The rapid emergence and development of quantum computers offer a promising route to systematically tackle this problem. Recent work by Huggins et al.[1] proposed a hybrid quantum-classical quantum Monte Carlo (QC-QMC) algorithm using Clifford shadows to determine the ground state of a Fermionic Hamiltonian. This approach displayed inherent noise resilience and the potential for improved accuracy compared to its purely classical counterpart. Nevertheless, the use of Clifford shadows introduces an exponentially scaling post-processing cost. In this work, we investigate an improved QC-QMC scheme utilizing the recently developed Matchgate shadows technique [2], which removes the aforementioned exponential bottleneck. We observe from experiments on quantum hardware that the use of Matchgate shadows in QC-QMC is inherently noise robust. We show that this noise resilience has a more subtle origin than in the case of Clifford shadows. Nevertheless, we find that classical post-processing, while asymptotically efficient, requires hours of runtime on thousands of classical CPUs for even the smallest chemical systems, presenting a major challenge to the scalability of the algorithm.
title Evaluating a quantum-classical quantum Monte Carlo algorithm with Matchgate shadows
topic Quantum Physics
Chemical Physics
url https://arxiv.org/abs/2404.18303