论文标题
石墨烯的相关量子动力学
Correlated quantum dynamics of graphene
论文作者
论文摘要
相位空间表示是一种剂量和费米子系统动力学的方法家族，它们是通过将系统的密度矩阵映射到准概率密度的，而汉密尔顿的liouville-von neumann方程可用于相应的密度差分方程，以实现概率。我们在这里调查了一个近似相位空间表示的准确性和计算效率，称为费米子截断器的Wigner近似（FTWA），应用于费米 - 荷兰模型。在多体二维系统上，带有跳高强度和库仑$ u $来代表石墨烯的电子结构，该方法可以捕获一阶（站点占用）和二阶（相关功能）的时间演变，比均值视野Hartree-Field，Hartre-Field，Hartre-Field，Hartre-Field，Hartre-Field，Hartre-Fock方法。还将FTWA与针对较小系统的精确对角线化方法的结果进行了比较，通常发现一致性是良好的。 FTWA量表的完全平行的计算需求与Hartree-fock方法相同，此处考虑的最大系统包含198个晶格位点。
Phase-space representations are a family of methods for dynamics of both bosonic and fermionic systems, that work by mapping the system's density matrix to a quasi-probability density and the Liouville-von Neumann equation of the Hamiltonian to a corresponding density differential equation for the probability. We investigate here the accuracy and the computational efficiency of one approximate phase-space representation, called the fermionic Truncated Wigner Approximation (fTWA), applied to the Fermi-Hubbard model. On a many-body 2D system, with hopping strength and Coulomb $U$ tuned to represent the electronic structure of graphene, the method is found to be able to capture the time evolution of first-order (site occupation) and second-order (correlation functions) moments significantly better than the mean-field, Hartree-Fock method. The fTWA was also compared to results from the exact diagonalization method for smaller systems, and in general the agreement was found to be good. The fully parallel computational requirement of fTWA scales in the same order as the Hartree-Fock method, and the largest system considered here contained 198 lattice sites.
