发表机构
Oak Ridge National Laboratory; University of North Dakota; University of Florida（橡树岭国家实验室; 北达科他大学; 佛罗里达大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
针对多激子激发态难以准确描述的问题，提出了经典[T]微扰修正的q-sc-EOM-UCCSD方法，通过经典二阶微扰捕获三重激发效应，在CH+和BH分子基准上显著提升精度，强调高阶激发算符的重要性。
AI 中文摘要
激发电子态难以准确且可处理地建模，尤其是那些具有多激子特征的激发态。可扩展的单参考激发态方法通常无法描述此类态，因为它们受到平均场近似缺陷和/或忽略高阶激发算符的影响。为解决这一问题，我们推导了量子自洽运动方程幺正耦合簇单双激发（q-sc-EOM-UCCSD）方法的[T]微扰修正。该方法通过量子计算机上q-sc-EOM-UCCSD计算后的多体微扰理论二阶经典步骤来捕获三重激发效应。所发展的微扰修正具有$\mathcal{O}(N^7)$的经典计算时间标度。我们将[T]纳入一种混合计算策略，其中来自混合量子-经典q-sc-EOM-UCCSD算法的有效哈密顿量的特征向量被传递到经典计算机，该计算机执行[T]修正所需的后处理。[T]的益处通过在涵盖等电子CH$^+$和BH分子的多种电子激发态的基准测试中得到量化。我们发现，将[T]修正添加到q-sc-EOM-CCSD的Trotter化和全算符变体中，可以比基线q-sc-EOM-UCCSD提供显著的改进。我们的评估清楚地表明了在q-sc-EOM-UCCSD中考虑高阶激发算符的重要性，量化了[T]修正的整体成功，并讨论了其一些局限性。
英文摘要
Excited electronic states are difficult to accurately and tractably model, particularly those exhibiting multiexcitonic character. Scalable single-reference excited state methods typically fail to describe such states as they suffer from the defects of the mean-field approximation and/or neglect higher-rank excitation operators. To address this, we derive the [T] perturbative correction to the quantum self-consistent equation-of-motion unitary coupled cluster singles and doubles (q-sc-EOM-UCCSD) method. The method captures triple excitation effects through a classical step of second-order in many-body perturbation theory following a q-sc-EOM-UCCSD calculation on a quantum computer. The perturbative correction developed has a $\mathcal{O}(N^7)$ classical computational time scaling. We incorporate [T] into a hybrid compute strategy wherein eigenvectors of the effective Hamiltonian from the hybrid quantum-classical q-sc-EOM-UCCSD algorithm are relayed to a classical computer which performs the postprocessing required for the [T] correction. The benefits of [T] are quantified in a benchmark covering a variety of electronically excited states of the isoelectronic CH$^+$ and BH molecules. We find that the addition of the [T] correction to both trotterized and full operator variants of q-sc-EOM-CCSD can offer dramatic improvements over baseline q-sc-EOM-UCCSD. Our assessment clearly demonstrates the importance of considering higher-rank excitation operators in q-sc-EOM-UCCSD, quantifies the overall success of the [T] correction, and discusses some of its limitations.
