# Spectroscopy of the Hubbard dimer: the spectral potential

 Title Spectroscopy of the Hubbard dimer: the spectral potential Publication Type Palaiseau Article Acknowledgements Marie Curie, ERC DOI 10.1140/epjb/e2018-90277-3 Vanzini, M, Reining, L, Gatti, M Year of Publication 2018 Journal The European Physical Journal B Volume 91 URL https://doi.org/10.1140/epjb/e2018-90277-3 Keywords theory Abstract The spectral potential is the dynamical generalization of the Kohn–Sham potential. It targets, in principle exactly, the spectral function in addition to the electronic density. Here we examine the spectral potential in one of the simplest solvable models exhibiting a non-trivial interplay between electron-electron interaction and inhomogeneity, namely the asymmetric Hubbard dimer. We discuss a general strategy to introduce approximations, which consists in calculating the spectral potential in the homogeneous limit (here represented by the symmetric Hubbard dimer) and importing it in the real inhomogeneous system through a suitable connector''. The comparison of different levels of approximation to the spectral potential with the exact solution of the asymmetric Hubbard dimer gives insights about the advantages and the difficulties of this connector strategy for applications in real materials.
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