Efficient calculation of unbiased expectation values in diffusion quantum Monte Carlo
Efficient calculation of unbiased expectation values in diffusion quantum Monte Carlo
复制标题
扩散量子蒙特卡罗中无偏期望值的高效计算
DOI：
10.1103/physrevb.86.201107
复制
发表时间：
2012
影响因子：
3.7
通讯作者：
S. Russo
中科院分区：
文献类型：
--
作者：
M. Per;I. Snook;S. Russo
尽管量子蒙特卡罗方法在解决量子多体问题方面的实用性已得到证实，但由于存在较大且有时发散的统计误差，许多重要的可观测值难以计算。目前的技术水平允许构造重整化估计量，其导致有限方差，但总是包含一些系统偏差。我们提出了一种简单的方法，用于计算扩散量子蒙特卡罗方法中局部算子的无偏期望值，该方法适用于裸估计器和重正化估计器，可以准确计算力等重要属性。
Despite the proven utility of quantum Monte Carlo methods in addressing the quantum many-body problem, many important observables are difficult to calculate due to the presence of large, and sometimes divergent, statistical errors. The present state of the art allows the construction of renormalized estimators which result in finite variances, but which invariably include some systematic bias. We present a simple method for calculating unbiased expectation values of local operators in the diffusion quantum Monte Carlo method which is applicable to both bare and renormalized estimators, allowing the accurate calculation of important properties such as forces.