Perturbative Variational Quantum Eigensolver via Reduced Density Matrices

Fuente: arXiv
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Main Authors: Zheng, Yuhan, Guo, Yibin, Zhang, Huili, Liu, Jie, Zeng, Xiongzhi, Cai, Xiaoxia, Li, Zhenyu, Yang, Jinlong
Format: Preprint
Published: 2025
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author Zheng, Yuhan
Guo, Yibin
Zhang, Huili
Liu, Jie
Zeng, Xiongzhi
Cai, Xiaoxia
Li, Zhenyu
Yang, Jinlong
author_facet Zheng, Yuhan
Guo, Yibin
Zhang, Huili
Liu, Jie
Zeng, Xiongzhi
Cai, Xiaoxia
Li, Zhenyu
Yang, Jinlong
contents Current noisy intermediate-scale quantum (NISQ) devices remain limited in their ability to perform accurate quantum chemistry simulations due to restricted numbers of high-fidelity qubits and short coherence times. To overcome these challenges, we introduce the perturbative variational quantum eigensolver (VQE-PT), a hybrid quantum-classical algorithm that augments VQE with perturbation theory to account for electron correlation effects beyond a compact active space. Within this framework, the effective Hamiltonian in the active space is solved by VQE, and the perturbative energy correction is computed from reduced density matrices, thereby avoiding any increase in circuit depth or qubit overhead. We benchmark the proposed algorithm through numerical simulations on HF and N$_2$, demonstrating systematic improvements over standard VQE within compact active spaces. Furthermore, we perform an experimental realization on the Quafu superconducting quantum processor for $\rm F_2$, where, in conjunction with robust error mitigation strategies, the method achieves high accuracy (a mean absolute error of 1.2 millihartree) along the potential energy surface. These results demonstrate VQE-PT as a practical and resource-efficient pathway for incorporating dynamic correlation in quantum chemistry simulations.
format Preprint
id arxiv_https___arxiv_org_abs_2504_02340
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Perturbative Variational Quantum Eigensolver via Reduced Density Matrices
Zheng, Yuhan
Guo, Yibin
Zhang, Huili
Liu, Jie
Zeng, Xiongzhi
Cai, Xiaoxia
Li, Zhenyu
Yang, Jinlong
Quantum Physics
Current noisy intermediate-scale quantum (NISQ) devices remain limited in their ability to perform accurate quantum chemistry simulations due to restricted numbers of high-fidelity qubits and short coherence times. To overcome these challenges, we introduce the perturbative variational quantum eigensolver (VQE-PT), a hybrid quantum-classical algorithm that augments VQE with perturbation theory to account for electron correlation effects beyond a compact active space. Within this framework, the effective Hamiltonian in the active space is solved by VQE, and the perturbative energy correction is computed from reduced density matrices, thereby avoiding any increase in circuit depth or qubit overhead. We benchmark the proposed algorithm through numerical simulations on HF and N$_2$, demonstrating systematic improvements over standard VQE within compact active spaces. Furthermore, we perform an experimental realization on the Quafu superconducting quantum processor for $\rm F_2$, where, in conjunction with robust error mitigation strategies, the method achieves high accuracy (a mean absolute error of 1.2 millihartree) along the potential energy surface. These results demonstrate VQE-PT as a practical and resource-efficient pathway for incorporating dynamic correlation in quantum chemistry simulations.
title Perturbative Variational Quantum Eigensolver via Reduced Density Matrices
topic Quantum Physics
url https://arxiv.org/abs/2504.02340