The effect of six-point one-particle reducible local interactions in the dual fermion approach
The effect of six-point one-particle reducible local interactions in the dual fermion approach
复制标题
双费米子方法中六点单粒子可约局部相互作用的影响
DOI：
--
复制
发表时间：
2012
期刊：
影响因子：
--
通讯作者：
A. Katanin
中科院分区：
文献类型：
--
作者：
A. Katanin
我们制定的双重费米子方法的强关联电子系统的晶格和双重有效的相互作用，通过使用协变分裂公式。这使我们能够考虑六点单粒子可约相互作用的影响，这通常被忽略的对偶费米子方法。我们表明，考虑一个粒子约六点（以及更高的顺序）顶点是至关重要的图形的一致性，这种方法。特别是，对偶和晶格自能之间的关系，在对偶费米子的方法，推导出隐含的帐户的影响的图表，包含六点和更高阶的本地一粒子可约顶点，并应谨慎应用，如果这些顶点被忽略。除此之外，自能反馈的处理还通过六点和更高阶的顶点进行修改;这些顶点对于解释晶格自能的一些非局部修正也很重要，它们在局部四点中具有相同的顺序。顶点作为该方法中通常考虑的图。这些观测结果突出了六点和高阶顶点在对偶费米子方法中的重要性，并呼吁发展基于单粒子不可约量的新的非局部波动处理方案。
We formulate the dual fermion approach for strongly correlated electronic systems in terms of the lattice and dual effective interactions, obtained by using the covariation splitting formula. This allows us to consider the effect of six-point one-particle reducible interactions, which are usually neglected by the dual fermion approach. We show that the consideration of one-particle reducible six-point (as well as higher order) vertices is crucially important for the diagrammatic consistency of this approach. In particular, the relation between the dual and lattice self-energy, derived in the dual fermion approach, implicitly accounts for the effect of the diagrams, containing six-point and higher order local one-particle reducible vertices, and should be applied with caution, if these vertices are neglected. Apart from that, the treatment of the self-energy feedback is also modified by six-point and higher order vertices; these vertices are also important to account for some non-local corrections to the lattice self-energy, which have the same order in the local four-point vertices as the diagrams usually considered in the approach. These observations highlight an importance of six-point and higher order vertices in the dual fermion approach, and call for the development of new schemes of treatment of non-local fluctuations, which are based on one-particle irreducible quantities.