GW wave functions

[Tobias Frank]

Hello everybody, I was at the Yambo workshop in April and enjoyed it a lot!

Now I have a question. Is it possible to get the wave functions of the GW states, in particular how they are expanded in terms of plane waves? I would like to use them to apply another theory on them.

Best regards,
Tobi

[myrta gruning]

Dear Tobias

In the GW approximation, the quasiparticles energies are obtained from first order perturbation theory starting from the KS energies. The wave-functions, at this order in the perturbation are then just the KS wave-functions.

In order to be able to get the QP wavefunction one need some self-consistent approach. For that there are several approaches as the GW self-energy is not a Hermitian operator, and one as to find a Hermitian approximation to that.

One option is to neglect frequency dependent that gives the so-called COH-SEX approximation (self-consistent), other options are for example the QSGW approach of Kotani and can Schilfgaarde. Those are however not available in Yambo at the moment.