4 papers
Beyond Born-Oppenheimer Green's function theories: absolute and relational
Ville J. Härkönen
We consider quantum field theoretic many-body Green's function approach to solve the Coulomb many-body problem. The earlier beyond Born-Oppenheimer Green's function theories are ab…
Giant Kohn anomaly and chiral phonons in the charge density wave phase of 1H-NbSe
Susy Exists, Sougata Mardanya, Robert Markiewicz +6
Despite extensive investigations, many aspects of charge density waves (CDWs) remain elusive, especially the relative roles of electron-phonon coupling and Fermi surface nesting as…
Quantum Field Theory of Electrons and Nuclei
Ville J. Härkönen
We develop a non-relativistic quantum field theory of electrons and nuclei based on the Coulomb Hamiltonian. We derive the exact equations of motion and write these equations in th…
On the breakdown of the Born-Oppenheimer approximation in LiH and LiD
Ville J. Härkönen
We compute the ab-initio electron density beyond the strict Born-Oppenheimer approximation in crystalline LiH and LiD with density functional methods. By taking into account the qu…