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

• URL: http://arxiv.org/abs/2012.07047v1
• Date: Sun, 13 Dec 2020 12:22:41 GMT
• Title: An efficient adaptive variational quantum solver of the Schrodinger equation based on reduced density matrices
• Authors: Jie Liu and Zhenyu Li and Jinlong Yang
• Abstract summary: We present an efficient adaptive variational quantum solver of the Schrodinger equation based on ADAPT-VQE. This new algorithm is quite suitable for quantum simulations of chemical systems on near-term noisy intermediate-scale hardware.
• Score: 8.24048506727803
• License: http://creativecommons.org/publicdomain/zero/1.0/
• 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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