Variational quantum eigensolver (VQE) has emerged as a promising method for investigating ground state properties in quantum chemistry, materials science, and condensed matter physics. However, the conventional VQE method generally lacks systematic improvement and convergence guarantees, particularly when dealing with strongly correlated systems. In light of these challenges, we present a novel framework called orbital expansion VQE (OE-VQE) to address these limitations. The key idea is to devise an efficient convergence path by utilizing shallower quantum circuits, starting from a highly compact active space and gradually expanding it until convergence to the ground state is achieved. To validate the effectiveness of the OE-VQE framework, we conducted benchmark simulations on several small yet representative molecules, including the H6 chain, H10 ring and N2 . The simulation results demonstrate that our proposed convergence paths significantly enhance the performance of conventional VQE. Overall, our work sheds valuable insight into the simulation of molecules based on shallow quantum circuits, offering a promising avenue for advancing the efficiency and accuracy of VQE approaches in tackling complex molecular systems.

中文翻译：

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轨道展开变分量子本征求解器


变分量子本征求解器 (VQE) 已成为研究量子化学、材料科学和凝聚态物理中基态特性的一种有前途的方法。然而，传统的VQE方法普遍缺乏系统性改进和收敛保证，特别是在处理强相关系统时。鉴于这些挑战，我们提出了一种称为轨道扩展 VQE（OE-VQE）的新颖框架来解决这些限制。关键思想是利用较浅的量子电路设计一条有效的收敛路径，从高度紧凑的活动空间开始，逐渐扩展它，直到收敛到基态。为了验证 OE-VQE 框架的有效性，我们对几个具有代表性的小分子进行了基准模拟，包括 H6 链、H10 环和 N2。仿真结果表明，我们提出的收敛路径显着提高了传统 VQE 的性能。总的来说，我们的工作为基于浅量子电路的分子模拟提供了宝贵的见解，为提高 VQE 方法处理复杂分子系统的效率和准确性提供了一条有前途的途径。