  Realistic calculations of electron addition and removal spectra rely most
often on Green's functions and complex, non-local self-energies. We introduce a
shortcut to obtain the spectral function directly from a local and
frequency-dependent, yet real, potential. We calculate this potential in the
homogeneous electron gas (HEG), and we design a connector which prescribes the
use of the HEG results to calculate spectral functions of real materials.
Benchmark results for several solids demonstrate the potential of our approach.
