论文标题
固定节点扩散蒙特卡洛和无量尺量量子蒙特卡洛的系统比较和交叉验证
Systematic Comparison and Cross-validation of Fixed-Node Diffusion Monte Carlo and Phaseless Auxiliary-Field Quantum Monte Carlo in Solids
论文作者
论文摘要
量子蒙特卡洛（QMC）方法是模拟相关电子系统的一些最准确的方法。我们研究了两种此类方法的兼容性，优势和劣势，即扩散蒙特卡洛（DMC）和辅助场量子蒙特卡洛（AFQMC）。两种方法中采用的多确定试验波函数都是使用配置相互作用使用迭代（CIPSI）技术生成的。完整的基集与CIPSI估计的完整配置相互作用（CBS-FCI）能量在DMC和AFQMC之间的比较研究中用作参考。通过关注一组规范有限尺寸的固态系统，我们表明，一旦消除了基于基集效应和系统的偏见，可以将这两种QMC方法用于系统地趋向相同的能量。与DMC相比，AFQMC对试验波函数的依赖性要小得多，同时表现出更大的基集依赖性。我们概述了改进这些方法的剩余挑战和机会。
Quantum Monte Carlo (QMC) methods are some of the most accurate methods for simulating correlated electronic systems. We investigate the compatibility, strengths and weaknesses of two such methods, namely, diffusion Monte Carlo (DMC) and auxiliary-field quantum Monte Carlo (AFQMC). The multi-determinant trial wave functions employed in both approaches are generated using the configuration interaction using a perturbative selection made iteratively (CIPSI) technique. Complete basis set full configuration interaction (CBS-FCI) energies estimated with CIPSI are used as a reference in this comparative study between DMC and AFQMC. By focusing on a set of canonical finite size solid state systems, we show that both QMC methods can be made to systematically converge towards the same energy once basis set effects and systematic biases have been removed. AFQMC shows a much smaller dependence on the trial wavefunction than DMC while simultaneously exhibiting a much larger basis set dependence. We outline some of the remaining challenges and opportunities for improving these approaches.
