Fully quantum treatment of the Landau--Pomeranchuk--Migdal effect in QED   and QCD
  For the first time a rigorous quantum treatment of the Landau-Pomeranchuk-Migdal effect in QED and QCD is given. The rate of photon (gluon) radiation by an electron (quark) in medium is expressed through the Green's function of a two-dimensional Schr\"odinger equation with an imaginary potential. In QED this potential is proportional to the dipole cross section for scattering of $e^{+}e^{-}$ pair off an atom, in QCD it is proportional to the cross section of interaction with color centre of the color singlet quark-antiquark-gluon system. 
B.G.Zakharov (Landau Institute for Theoretical Physics, Moscow)