Electromgnetic-gravitational cross-sections in external elctromagnetic   fields
  The classical processes: the conversion of photons into gravitons in the static electromagnetic fields are considered by using Feynman perturbation techniques. The differential cross sections are presented for the conversion in the electric field of the flat condesor and the magnetic field of the selenoid. A numerical evaluation shows that the cross sections may have the observable value in the present technical scenario. 
Hoang Ngoc Long, Dang Van Soa, and Tuan A. Tran