标题： 带有量子选择组态相互作用的辅助场量子蒙特卡罗方法 显示英文标题

标题： Auxiliary-field quantum Monte Carlo method with quantum selected configuration interaction

摘要： 我们提出使用量子选择组态相互作用（QSCI）方法生成的波函数作为相位无限制辅助场量子蒙特卡罗（ph-AFQMC）中的试探波函数。在QSCI框架中，电子组态是从量子计算机上实现的量子态中采样的。这些组态作为构建有效哈密顿量的基础状态，然后对其进行对角化以获得相应的本征态。使用此波函数，执行ph-AFQMC以在整个轨道空间中恢复动态电子相关性。预计使用QSCI试探波函数将提高量子-经典（QC）混合量子蒙特卡罗方法的可行性[Nature, 603, 416 (2022)]。我们将这种集成方法称为QC-QSCI-AFQMC，或简称为QSCI-AFQMC。该方法已在多个分子系统中得到验证。对于H2O和线性H4链，在使用大阪大学和RIKEN的超导量子计算机进行的大多数研究中，我们相对于完全组态相互作用实现了化学精度。此外，将QSCI-AFQMC应用于有机分子中的O-H键解离，突显了在量子硬件上捕捉静态相关性和通过经典后处理引入动态相关性的互补协同作用。对于N2，当使用无噪声模拟器执行QSCI-AFQMC时，其准确性与其他多种多参考电子结构理论相比名列前茅。尽管所提出的方法是基于当前量子设备上的小活性空间进行演示的，但该概念不限于少量量子比特的问题。QSCI-AFQMC可以与最先进的经典计算技术竞争，特别是在更大的活性空间中，显示出解决经典难以处理的量子化学问题的巨大潜力。 显示英文摘要

摘要： We propose using the wave function generated by the quantum selected configuration interaction (QSCI) method as the trial wave function in phaseless auxiliary-field quantum Monte Carlo (ph-AFQMC). In the QSCI framework, electronic configurations are sampled from the quantum state realized on a quantum computer. These configurations serve as basis states for constructing an effective Hamiltonian, which is then diagonalized to obtain the corresponding eigenstate. Using this wave function, ph-AFQMC is performed to recover the dynamical electron correlation across the whole orbital space. The use of the QSCI trial wave function is expected to improve the feasibility of the quantum-classical (QC) hybrid quantum Monte Carlo approach [Nature, 603, 416 (2022)]. We call this integrated approach QC-QSCI-AFQMC, or QSCI-AFQMC for short. This method is validated across several molecular systems. For H2O and a linear H4 chain, we achieved chemical accuracy in most investigations relative to full configuration interaction while utilizing superconducting quantum computers at Osaka University and RIKEN. Additionally, the application of QSCI-AFQMC to the O-H bond dissociation in an organic molecule highlights the complementary synergy between capturing static correlation on quantum hardware and incorporating dynamical correlation via classical post-processing. For the N2, when QSCI-AFQMC is executed with a noiseless simulator, it ranks among the most accurate methods compared to various multireference electronic structure theories. Although the proposed method is demonstrated using small active spaces on current quantum devices, the concept is not limited to few-qubit problems. The QSCI-AFQMC can compete with state-of-the-art classical computational techniques, particularly in larger active spaces, displaying considerable potential for resolving classically intractable problems in quantum chemistry.