Logarithmic corrections in the two-body QED problem

摘要: The logarithmic part of the Lamb shift, contribution relative order α3 log (1/α) to atomic state energy, is related usual infrared divergence. This fact allows one calculate easily such corrections in positronium, and derive recoil electron-electron terms Lambshift Hamiltonian many-electron atoms. Logarithmic energy next order, α4 (1/α), are a different, relativistic nature. Their calculation reduced ordinary perturbation theory for nonrelativistic Schrodinger equation. operators have Breit-type structure found by on-mass-shell diagrams. For calculated log-arithmic correction survives only n3S1 states constitutes (5/24)mα6 (1/α)/n3. α2 positronium decay rate also origin can be computed within same approach. Arguments presented favour large numerical factor (α/π)2 rate.