发表机构
Wesleyan University（卫斯理安大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文提出利用哈密顿量的微扰逆构建Krylov子空间，以改进Lanczos对角化对基态波函数的近似，并在二阶精度下验证其有效性，且计算成本与PT5相当。
AI 中文摘要
本文研究了在Lanczos算法中使用移位逆哈密顿量的方法。我们提出了一种微扰逆，并证明由它构成的Krylov子空间比哈密顿量本身更适于近似基态波函数。我们进一步证明，微扰逆在二阶上提供了对逆哈密顿量的足够精确的近似。自然，结果的质量取决于初始猜测的质量，这里我们使用Hartree-Fock、CISD、MP-PT1和EN-PT1波函数。最后，我们考察了该方法的标度，发现可以在与PT5相似的成本下获得准确的结果。
英文摘要
The use of the shifted inverse Hamiltonian in the Lanczos algorithm is examined. We present a perturbative inverse and demonstrate that the Krylov subspace formed from it is better suited to approximating the ground state wavefunction compared with the Hamiltonian itself. We further demonstrate that the perturbative inverse provides an adequately accurate approximation to the inverse Hamiltonian at second order. Naturally, the quality of the results depend on the quality of the initial guess, here we use the Hartree-Fock, CISD, MP-PT1, and EN-PT1 wavefunctions. Lastly, we examine the scaling of the method where we find that accurate results can be found for similar cost as PT5.
Comments6 pages, 7 figures
