Electron mass operator in a strong magnetic field
  The electron mass operator in a strong magnetic field is calculated by summation of the leading log contributions in all orders of the perturbation theory. An influence of the strong field on the virtual photon polarization operator is taken into account. The contribution of higher Landau levels of virtual electrons, along with the ground Landau level, is shown to be essential in the leading log approximation. 
A.V. Kuznetsov, N.V. Mikheev and M.V. Osipov (Yaroslavl State   (Demidov) University, Russia)