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arXiv · 2012.07047

An efficient adaptive variational quantum solver of the Schrodinger equation based on reduced density matrices

Jie Liu·Zhenyu Li·Jinlong Yang
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Abstract

Recently, an adaptive variational algorithm termed Adaptive Derivative-Assembled Pseudo-Trotter ansatz Variational Quantum Eigensolver (ADAPT-VQE) has been proposed by Grimsley et al. (Nat. Commun. 10, 3007) while the number of measurements required to perform this algorithm scales O(N^8). In this work, we present an efficient adaptive variational quantum solver of the Schrodinger equation based on ADAPT-VQE together with the reduced density matrix reconstruction approach, which reduces the number of measurements from O(N^8) to O(N^4). This new algorithm is quite suitable for quantum simulations of chemical systems on near-term noisy intermediate-scale hardware due to low circuit complexity and reduced measurement. Numerical benchmark calculations for small molecules demonstrate that this new algorithm provides an accurate description of the ground-state potential energy curves. In addition, we generalize this new algorithm for excited states with the variational quantum deflation approach and achieve the same accuracy as ground-state simulations.

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Jie Liu, Zhenyu Li, Jinlong Yang. 2020-12-13. An efficient adaptive variational quantum solver of the Schrodinger equation based on reduced density matrices. https://doi.org/10.1063/5.0054822

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