In this paper, we discuss the utilization of variational quantum solver (VQE) and recently introduced generalized unitary coupled cluster (GUCC) formalism for the diagonalization of downfolded/effective Hamiltonians in active spaces. In addition to effective Hamiltonians defined by the downfolding of a subset of virtual orbitals we also consider their form defined by freezing core orbitals, which enables us to deal with larger systems. We also consider various solvers to identify solutions of the GUCC equations. We use N₂, H₂O, and C₂H₄, as benchmark systems to illustrate the performance of the combined framework.

中文翻译：

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使用广义酉耦合簇 ansatz 对下折叠哈密顿量进行近似对角化的变分量子特征求解器

在本文中，我们讨论了变分量子求解器 (VQE) 和最近引入的广义酉耦合簇 (GUCC) 形式主义的利用，用于活动空间中下折叠/有效哈密顿量的对角化。除了由虚拟轨道子集的下折叠定义的有效哈密顿量之外，我们还考虑了由冻结核心轨道定义的形式，这使我们能够处理更大的系统。我们还考虑了各种求解器来识别 GUCC 方程的解。我们使用 N ₂、H ₂ O 和 C ₂ H ₄作为基准系统来说明组合框架的性能。