Parquet decomposition calculations of the electronic self-energy

Photoemission spectroscopy is one of the most direct routes to investigate electronic systems. However, if electron correlations are strong, the identification of the predominant scattering processes through the analysis of the photoelectron spectra becomes a formidable challenge. The authors introduce here a decomposition of the electronic self-energy (see image), based on the so-called parquet equations, which, as suggested by their name, take into account all scattering channels and their interconnections. The application of this new parquet decomposition to self-energies computed in the case of local Coulomb interaction in two-dimensions (2D Hubbard model) yields several new results. Future investigations based on parquet decompositions and/or the fluctuation diagnostics of the self-energy could shed further light on the microscopic processes controlling the spectral functions in correlated electron models.