论文标题
向量模型的大N扩展的系统重新召集：应用于Hubbard模型和$ 2 + 1 $ dimensional Qed
Systematic Resummation of the Large N expansion of Vector Models: Application to the Hubbard model and $2 + 1 $ dimensional QED
论文作者
论文摘要
我们引入了Hubbard模型中电荷密度相关函数的封闭方程层次结构和$ 2 + 1 $ dimensional QED。层次结构中的每个步骤都可以被视为一个与所有$ k-$点充电相关器相关的精确但无限方程的大$ n $截断。 $ n $是费米昂旋转组件的数量。层次结构中的每个步骤概括了无限数量的大$ n $图，包括所有固定订单的所有图表，$ k $ point函数和$ k \ leq k $。更高点功能被其领先的大$ N $行为所取代。最简单的截断为$ 2 $点功能提供了封闭的非线性方程。
We introduce a hierarchy of closed equations for charge density correlation functions in the Hubbard model and $2 + 1$ dimensional QED. Each step in the hierarchy can be considered a large $N$ truncation of an exact, but infinite set of equations relating all $k-$point charge correlators. $N$ is the number of fermion spin components. Each step in the hierarchy sums up an infinite number of large $N$ diagrams, including all diagrams up to some fixed order, for $k$ point functions with $k \leq K$. Higher point functions are replaced with their leading large $N$ behavior. The simplest truncation gives a closed nonlinear equation for the $2$ point function.
