由选定组态相互作用引导的选定耦合簇方法
Selected Coupled Cluster Guided by Selected Configuration Interaction
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中文总结 AI 辅助
本文提出选定耦合簇（SCC）方法，利用SCI波函数引导稀疏振幅空间，求解任意阶CC方程，在多种化学体系中实现快速收敛，优于SCI和SCI+PT2，并有效处理DMRG难以收敛的高维体系。
中文摘要 AI 辅助
耦合簇（CC）理论是最流行的关联波函数方法之一，然而，截断至较高阶的CC方法因其陡峭的计算成本缩放而限制了其应用。现代选定组态相互作用（SCI）方法成功利用了基态波函数在行列式空间中的稀疏性，这启发了在指数形式的CC拟设中采用类似的方法。在本工作中，我们引入了选定耦合簇（SCC），这是一种任意阶稀疏CC方法，它在由SCI波函数引导的紧凑振幅空间内显式求解CC残差方程。SCC在稀疏振幅空间中优化CC振幅。利用一个试验性的即时（JIT）编译实现，我们针对多种化学体系，将SCC与SCI、SCI+PT2、标准秩截断稠密CC（CCSD、CCSDT）以及DMRG进行了基准测试。我们证明，SCC展现出随SCI变分阈值快速、单调的收敛性，在紧阈值区域优于SCI并超越SCI+PT2。SCC还为高维拓扑结构提供了精确的能量，而DMRG通常在此类结构中随键维数收敛缓慢。因此，SCC为现代SCI工作流程提供了一种高效的即插即用增强方案。
英文摘要
Coupled Cluster (CC) theory is one of the most popular correlated wavefunction methods, yet the steep computational cost scaling of CC truncated at higher rank limits its application. Modern Selected Configuration Interaction (SCI) methods successfully exploit the sparsity of ground-state wavefunctions in the determinant space, motivating an analogous approach with the exponential CC ansatz. In this work, we introduce Selected Coupled Cluster (SCC), an arbitrary-order sparse CC method that explicitly solves the CC residual equations within a compact amplitude space guided by an SCI wavefunction. SCC optimizes the CC amplitudes in the sparse amplitude space. Using a pilot Just-in-Time (JIT) compiled implementation, we benchmark SCC against SCI, SCI+PT2, standard rank-truncated dense CC (CCSD, CCSDT), and DMRG across various chemical systems. We demonstrate that SCC exhibits fast, monotonic convergence with the SCI variational threshold, outperforming SCI and surpassing SCI+PT2 in the tight-threshold regime. SCC also provides accurate energies for high-dimensional topologies, where DMRG typically converges slowly with bond dimension. SCC thus presents an efficient drop-in enhancement for modern SCI workflows.
