We present an algorithm for calculating the local energy of a multi-Slater wave function in orbital space quantum Monte Carlo (QMC). Recent developments in selected configuration interaction methods have led to increased interest in using multi-Slater trial wave functions in various QMC methods. For an ab initio Hamiltonian, our algorithm has a cost scaling of O(n⁵ + n_c), as opposed to the O(n⁴n_c) scaling of existing orbital space algorithms, where n is the system size and n_c is the number of configurations in the wave function. We present our method using variational Monte Carlo calculations with the Jastrow multi-Slater wave function, although the formalism should be applicable for auxiliary field QMC. We apply it to polyacetylene and demonstrate the possibility of using a much larger number of configurations than possible using existing methods.

中文翻译：

---

轨道空间量子蒙特卡洛中多平板波函数的有效局部能量评估

我们提出了一种算法，用于计算轨道空间量子蒙特卡洛（QMC）中多Slater波函数的局部能量。所选配置交互方法的最新发展引起了人们对在各种QMC方法中使用多Slater试验波函数的兴趣增加。对于从头算起的哈密​​顿量，我们的算法的成本标度为O（n ⁵ + n _c），与现有轨道空间算法的O（n ⁴ n _c）标度相反，其中n是系统大小，n _c是wave函数中的配置数量。尽管形式主义应该适用于辅助场QMC，但我们提出了使用带有Jastrow多重Slater波函数的变分蒙特卡罗计算方法。我们将其应用于聚乙炔，并证明了使用比现有方法更大数量的配置的可能性。