Figure 2
The diagrammatic representation of \(G({\bf{r}},{\bf{r}}^{\prime} )\) according to TFD theory. The zigzags between two points r and r′ (with two double circles at the ends) are \(G({\bf{r}},{\bf{r}}^{\prime} )\), the wavy lines between r and r′ are 1/|r − r′| which is the electrostatic potential, the gray circles with a cross inside are the external potential (disorder), and the double circles with r are the full electronic density n(r). For the details see Appendix 1. In this expansion the first term on the right hand (second line) is f3 and the second term (third line) is f1 in the appendix.
