在辅助玻色基态上对扩散蒙特卡洛的激发光谱的评估
Fernando A Reboredo1, Paul R C Kent2, Jaron T Krogel1
1Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
The Journal of chemical physics
|September 19, 2023
概括
本研究引入了一种改进的变量蒙特卡洛 (VMC) 方法来计算电子刺激. 与现有方法相比,新的辅助玻色子 (AB) 方法提高了准确性,并降低了基准要求.
科学领域:
- 计算量子化学 计算量子化学
- 多体物理多体物理
- 量子蒙特卡洛方法 量子蒙特卡洛方法
背景情况:
- 变量蒙特卡洛 (VMC) 是研究量子系统的一个关键方法.
- 由于Jastrow因子的局限性,标准VMC方法往往难以准确地描述电子激发.
- 像平均场和配置交互 (CI) 这样的近似可以引入错误,特别是在有限的基础集.
研究的目的:
- 开发一种新的计算方法,改进变量蒙特卡洛 (VMC) 方法来计算电子激发.
- 通过结合辅助玻色子 (AB) 状态来提高量子系统模拟的准确性和效率.
- 为了减少基数组的截断错误,并改善费米电子系统中电子相关性的描述.
主要方法:
- 在VMC中用辅助玻色子 (AB) 基态乘以子元件因子取代了传统的Jastrow因子.
- 利用辅助有效潜力引导AB系统的配置空间向原始费米子系统的激发方向.
- 采用扩散蒙特卡洛 (DMC) 来统计处理AB基态,同时在计算激发能量的基础上扩展费米离子元件.
主要成果:
- 辅助玻色子 (AB) 基态因子有效地结合了标准Jastrow因子所遗漏的电子相关性.
- 这种新方法在基础集大小方面表现出优于配置交互 (CI) 和VMC方法的性能,以获得同等的准确性.
- 在可溶性模型系统中进行测试,AB方法与精确的分析数据和现有的计算方法有很好的一致性.
结论:
- 拟议的辅助玻色子 (AB) 方法为计算电子激发提供了比常规变量蒙特卡洛 (VMC) 的显著改进.
- 这种方法有效地纠正来自近似固态和截断相互作用的不准确性,减少基础设置错误.
- 在现有的计算代码中实现是可行的,通过利用基础状态和激发计算的既定程序来实现.
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