Operator Projection Method Applied to the Single-Particle Green's Function in the Hubbard Model
Operator Projection Method Applied to the Single-Particle Green's Function in the Hubbard Model
复制标题
算子投影法在哈伯德模型中单粒子格林函数的应用
DOI：
10.1143/jpsj.70.632
复制
发表时间：
2000
期刊：
影响因子：
--
通讯作者：
M. Imada
中科院分区：
文献类型：
--
作者：
S. Onoda;M. Imada
通过扩展算子投影法(OPM)，建立了一个新的多体关联系统的非摄动框架。这种方法提供了一种系统的扩展，使我们能够在提取较高能量层次后投影到低能量结构中。这种方法也为系统地考虑集体激发的影响开辟了一条途径。考虑高能Mott-Hubbard结构中的磁涨落和电荷涨落，利用该投影研究了Hubbard模型中金属-绝缘体的Mott-Hubbard转变。在半填充时，在分离的两个带之间正确地再现了Mott-Hubbard间隙。出现了与Mott-Hubbard带共存的近半填充、强重整化的低能单粒子激发。强调了动量相关的自能在结果中的意义。
A new non-perturbative framework for many-body correlated systems is formulated by extending the operator projection method (OPM). This method offers a systematic expansion which enables us to project into the low-energy structure after extracting the higher-energy hierarchy. This method also opens a way to systematically take into account the effects of collective excitations. The Mott-Hubbard metal-insulator transition in the Hubbard model is studied by means of this projection beyond the second order by taking into account magnetic and charge fluctuations in the presence of the high-energy Mott-Hubbard structure. At half filling, the Mott-Hubbard gap is correctly reproduced between the separated two bands. Near half filling, strongly renormalized low-energy single-particle excitations coexisting with the Mott-Hubbard bands are shown to appear. The significance of the momentum-dependent self-energy in the results is stressed.