Quasiclassical 1/N Energy‐Formulas for Relativistic Two‐Body Systems

Quickly tractable energy‐formulas for relativistic two‐body systems are established to first 1/N‐order in terms of general classical Hamiltonians ( m 1 ≥ m 2 ). Arbitrary spherically‐symmetrical vector and/or scalar potentials are assumed. Such Hamiltonians, which have to be converted into related non‐relativistic ones, play the role of a dominant zeroth‐order approximation (an exact description) in the case of two fermions (two bosons). Proofs have also been given that the 1/N‐method is quite suitable for the systematic description of order‐dependent contributions to the energy of Coulomb‐Bethe‐Salpeter systems, now to α 6 ‐order.