Perturbations for the Coulomb - Kepler problem on de Sitter space-time
In the Schrodinger picture of the Dirac quantum mechanics, defined in charts with spatially flat Robertson-Walker metrics and Cartesian coordinates the perturbation theory is applied to the interacting part of the Hamiltonian operator produced by the minimal coupling with the gravitational field. First and second order perturbations are computed.
gr-qc↗