Yambo Community Forum

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

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.