The GW approximation (GWA) is an approximation made in order to calculate the self-energy of a many-body system of electrons.[1][2][3] The approximation is that the expansion of the self-energy Σ in terms of the single particle Green's function G and the screened Coulomb interaction W (in units of )
can be truncated after the first term:
In other words, the self-energy is expanded in a formal Taylor series in powers of the screened interaction W and the lowest order term is kept in the expansion in GWA.
- ^ Hedin, Lars (1965). "New Method for Calculating the One-Particle Green's Function with Application to the Electron-Gas Problem". Phys. Rev. 139 (3A): A796–A823. Bibcode:1965PhRv..139..796H. doi:10.1103/PhysRev.139.A796. S2CID 73720887.
- ^ Aulbur, Wilfried G.; Jönsson, Lars; Wilkins, John W. (2000). "Quasiparticle Calculations in Solids". Solid State Physics. 54: 1–218. doi:10.1016/S0081-1947(08)60248-9. ISBN 9780126077544. ISSN 0081-1947.
- ^ Aryasetiawan, F; Gunnarsson, O (1998). "The GW method". Reports on Progress in Physics. 61 (3): 237–312. arXiv:cond-mat/9712013. Bibcode:1998RPPh...61..237A. doi:10.1088/0034-4885/61/3/002. ISSN 0034-4885. S2CID 119000468.