Photoemission spectroscopy from the three-body Green's function

We present an original approach for the calculation of direct and inverse photo-emission spectra from first principles.

Our method uses the three-body Green's function as a key quantity instead of the one-body Green's function as is traditionally done.

We show that, contrary to the one-body Green's function, satellites are already present in the corresponding non-interacting Green's function.

Therefore, quasiparticles and satellites are treated on an equal footing in our approach.

Moreover, we propose a simple static three-body self-energy that can be applied in practical calculations on real systems since it requires standard numerical tools readily available in all computer codes.