论文标题
双重效率方法作为相关费米子的通用参考系统方法的原型
Dual fermion method as a prototype of generic reference-system approach for correlated fermions
论文作者
论文摘要
我们提出了双重费用方案的纯图衍生物[Phys。 Rev. B 77（2008）033101]。该派生尤其清楚地表明，只要它具有与原始系统相同的交互项，就可以为任意参考系统开发类似的方案。因此，参考问题的当地或原始问题的性质是晶格的性质，没有限制。我们提出了新的论点，支持将双重分母保持在晶格自我能源的表达中，独立于双重相互作用的截断。例如，我们介绍了半填充2D哈伯德模型的计算结果，并选择了$ 2 \ times2 $ plaquette，其定期边界条件作为参考系统。我们观察到获得的结果与数值精确的晶格量子蒙特卡洛数据非常吻合。
We present a purely diagrammatic derivation of the dual fermion scheme [Phys. Rev. B 77 (2008) 033101]. The derivation makes particularly clear that a similar scheme can be developed for an arbitrary reference system provided it has the same interaction term as the original system. Thereby no restrictions are imposed by the locality of the reference problem or by the nature of the original problem as a lattice one. We present new arguments in favour of keeping the dual denominator in the expression for the lattice self-energy independently of the truncation of the dual interaction. As an example we present the computational results for the half-filled 2D Hubbard model with the choice of a $2\times2$ plaquette with periodic boundary conditions as a reference system. We observe that obtained results are in a good agreement with numerically exact lattice quantum Monte Carlo data.
