Many-body Green's function theory of electrons and nuclei beyond the Born-Oppenheimer approximation
Ville J. Härkönen, Robert van Leeuwen, Eberhard K. U. Gross
The method of many-body Green's functions is developed for arbitrary systems of electrons and nuclei starting from the full (beyond Born-Oppenheimer) Hamiltonian of Coulomb interactions and kinetic energies. The theory presented here resolves the problems arising from the translational and rotational invariance of this Hamiltonian that afflict the existing many-body Green's function theories. We derive a coupled set of exact equations for the electronic and nuclear Green's functions and provide a systematic way to approximately compute the properties of arbitrary many-body systems of electrons and nuclei beyond the Born-Oppenheimer approximation. The case of crystalline solids is discussed in detail.
arXiv:1906.06592•Physical review. B./Physical review. B•Jun 22, 2020•18 citations