AI 中文总结
该研究为多费米子系统提出基于随机规范自由度的新颖QMC方法，在无相位AFQMC框架内，重新解释力偏置为漂移规范，探索费米规范并提出对称投影采样方案，应用于Lipkin-Meshkov-Glick模型，结果显示可提高精度和减少波动。
AI 中文摘要
我们通过利用无相位辅助场量子蒙特卡罗（AFQMC）框架内最初在高斯相空间量子蒙特卡罗中开发的随机规范自由度，为相互作用的多费米子系统提出了新颖的量子蒙特卡罗（QMC）方法。特别是，我们将无相位AFQMC中的传统力偏置重新解释为漂移规范，并基于通过混合估计器定义的约化单粒子密度矩阵的自然轨道探索费米规范，产生随机的、与时间相关的类似哈特里 - 福克动力学。我们提出了一种对称投影采样方案以提高采样效率。作为概念验证，我们将这些规范增强的AFQMC方法应用于一个简单的壳模型哈密顿量：Lipkin-Meshkov-Glick模型。数值结果说明了随机规范在提高精度和减少波动方面的潜力，强调了将这些新技术推进到更实际的壳模型应用的前景。
英文摘要
We propose novel Quantum Monte Carlo (QMC) methods for interacting many-fermion systems by leveraging the stochastic gauge freedom, originally developed in Gaussian phase-space QMC, within the phaseless auxiliary-field QMC (AFQMC) framework. In particular, we reinterpret the conventional force bias in phaseless AFQMC as a drift gauge and explore Fermi gauges based on natural orbitals of a reduced one-body density matrix defined via a mixed estimator, yielding stochastic, time-dependent Hartree-Fock-like dynamics. We propose a symmetry-projection sampling scheme to enhance the sampling efficiency. As a proof of concept, we apply these gauge-augmented AFQMC methods to a simple shell-model Hamiltonian: the Lipkin-Meshkov-Glick model. Numerical results illustrate the potential of stochastic gauges to enhance accuracy and reduce fluctuations, underscoring the promise for advancing these new techniques toward more realistic shell-model applications.
Comments8 pages, 4 figures
