GW approximation

The GW approximation(GWA) is an approximation made in order to calculate the self-energy of a many-body system. The approximation is that the expansion of the self-energy in terms of the single particle Green function G and the screened interaction W

$\Sigma =GW+GWGWG+\cdots$

can be truncated after the first term:

$\Sigma \approx GW$

References

• L. Hedin, Phys. Rev. 139, A796 (1965).
• W.G. Aulbur, L. Jönsson and J.W. Wilkins, Solid State Physics 54, 1 (2000).