基于快速退火行列式选择的量子辅助选择组态相互作用加速方法
Accelerated Quantum-Assisted Selected Configuration Interaction via Fast-Annealing-Based Determinant Selection
- Kangwon National University（江原国立大学）
- Hanyang University（汉阳大学）
- Quantum Sub Inc.（量子子公司）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
该研究提出结合SCI与GBBD的QASCI方法，用快速退火求解QUBO问题以加速行列式选择，在Hn链、Li2S、N2体系中验证其可降低计算成本并保持化学精度，支持更大轨道空间的精确计算。
AI中文摘要：
全组态相互作用（FCI）在给定原子基组下可提供精确的电子结构，但计算成本随自旋轨道数呈指数增长。选择组态相互作用（SCI）方法通过仅保留最重要的斯莱特行列式缓解了这一限制，但重复识别重要行列式仍是主要计算瓶颈。本文提出一种量子辅助选择组态相互作用（QASCI）方法，将SCI与FCI哈密顿量的基于图的块对角化（GBBD）相结合。GBBD方法将FCI哈密顿量划分为独立块，其中行列式选择问题被表述为无约束二次二元优化（QUBO）问题。采用快速退火方法迭代求解用于构建SCI空间的行列式选择的QUBO问题。我们在STO-3G基组下的H8-H18氢链和Li2S上对该方法进行基准测试：对于Hn链，仅保留小部分斯莱特行列式即可达到化学精度，且该比例随n增大而降低，尽管FCI希尔伯特空间呈指数增长；对于Li2S，QASCI结果在保留远少于完整FCI空间行列式的同时仍保持在化学精度内。我们还将QASCI应用于6-31G基组下的N2，同时考虑活性轨道和全轨道处理：使用50000个行列式的全轨道QASCI计算，得到的基态能量低于包含12个自旋轨道和12个电子的活性空间内的FCI计算结果。这些结果表明，QASCI与GBBD方法的结合可在保持基于FCI的电子结构计算精度的同时，大幅降低行列式选择的计算成本，从而实现更大轨道空间的精确计算。
英文摘要：
Full configuration interaction (FCI) provides exact electronic structure within a given atomic basis, but its computational cost grows exponentially with the number of spin orbitals. Selected configuration interaction (SCI) methods alleviate this limitation by retaining only the most important Slater determinants. However, the repeated identification of important determinants remains a major computational bottleneck. We present a quantum assisted selected configuration interaction (QASCI) method that combines SCI with graph based block diagonalization (GBBD) of FCI Hamiltonian. The GBBD method partitions FCI Hamiltonian into independent blocks, within which determinant selection problem is formulated as a quadratic unconstrained binary optimization (QUBO) problem. The QUBO problems for selecting determinants to construct SCI space are iteratively solved using a fast annealing approach. We benchmark method on H8-H18 hydrogen chains and Li2S in STO3G basis. For Hn chains, chemical accuracy is achieved while retaining only a small fraction of Slater determinants, and this fraction decreases with increasing n, despite the exponential growth of the FCI Hilbert space. For Li2S, QASCI results remain within chemical accuracy while retaining substantially fewer determinants than the full FCI space. We apply QASCI to N2 using the 631G basis, considering both active orbital and full orbital treatments. The full orbital QASCI calculation, using 50000 determinants, yields a lower ground state energy than an FCI calculation within an active space comprising 12 spin orbitals and 12 electrons. These results demonstrate that the combination of QASCI and the GBBD approach can substantially reduce computational cost of determinant selection while maintaining the accuracy of FCI based electronic structure calculations, thereby enabling accurate calculations in larger orbital spaces.
