基于零自旋空间的量子选择配置相互作用方法及其在QC-QSCI-AFQMC中的应用
Doubling the size of quantum selected configuration interaction based on seniority-zero space and its application to QC-QSCI-AFQMC
AI总结：
本文提出DOCI-QSCI方法，通过扩展零自旋空间并结合ph-AFQMC，提升量子计算中轨道空间的处理能力，验证了其在H6链、N2解离和BODIPY-O2反应中的准确性。
摘要：
我们提出了双占据配置相互作用-量子选择配置相互作用（DOCI-QSCI），该方法从零自旋空间中采样。虽然使用这个空间可以有效地将量子比特预算翻倍，等于空间轨道数，但这种领域限制可能会损害定量精度。为了弥补这一点，我们通过它们的笛卡尔积扩展采样的位字符串到一个包含打破自旋决定性的确定性更大的空间。所得到的波函数也提出使用相位less辅助场量子蒙特卡洛（ph-AFQMC）的试态来恢复整个轨道空间中的动态相关性（DOCI-QSCI-AFQMC）。我们评估了所提出的方法在H6链、N2解离和单线态O2加到BODIPY染料中的应用。对于H6链，DOCI-QSCI-AFQMC在量子设备ibm kobe上重现了完整活化空间对应级别的准确性。对于N2和BODIPY-O2，在(14e, 28o)和高达(20e, 20o)的活化空间中，它产生了合理的结果，而单参考CCSD(T)在定性上失败。这些结果表明，DOCI-QSCI将传统QSCI可访问的轨道空间翻倍，随后的ph-AFQMC后处理提供了合理高的准确性。
英文摘要：
We propose doubly occupied configuration interaction-quantum selected configuration interaction (DOCI-QSCI), which samples from the seniority-zero space. While the use of this space effectively doubles the qubit budget, equaling the number of spatial orbitals, this sector restriction can compromise quantitative accuracy. To compensate for this, we expand sampled bitstrings via their Cartesian product into a larger space that includes seniority-breaking determinants. The resulting wave function is also proposed using the trial state in phaseless auxiliary-field quantum Monte Carlo (ph-AFQMC) to recover dynamical correlations across the full orbital space (DOCI-QSCI-AFQMC). We evaluate the proposed methods on the H6 chain, N2 dissociation, and the addition of singlet O2 to a BODIPY dye. For the H6 chain, DOCI-QSCI-AFQMC reproduces the accuracy of the level of the complete-active-space counterpart with the quantum device ibm kobe. For N2 and BODIPY-O2, with (14e, 28o) and up to (20e, 20o) active spaces, it yields reasonable results, whereas single-reference CCSD(T) fails qualitatively. These results demonstrate that the DOCI-QSCI doubles the orbital space accessible to conventional QSCI and subsequent ph-AFQMC post-processing delivers reasonably high accuracy.
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