The Two-Time Green’s Function and Screened Self-Energy for Two-Electron Quasi-Degenerate States

摘要: Precise predictions of atomic energy levels require the use QED, especially in highly-charged ions, where inner electrons have relativistic velocities. We present an overview two-time Green’s function method; this method allows one to calculate level shifts two-electron ions by including principle all QED effects, for any set states (degenerate, quasi-degenerate or isolated). evaluation contribution screened self-energy a finite-sized effective hamiltonian that yields through diagonalization.