Pair production in a strong magnetic field: the effect of a strong   background gravitational field
  We present the calculation of the probability production of an electron-positron pair in the presence of a strong magnetic field with time-varying strength. The calculation takes into account the presence of a strong, constant and uniform gravitational field in the same direction of the magnetic field. The results show that the presence of the gravitational field in general enhances the production of pairs. In particular, high-energy pairs are more likely produced in the presence of the gravitational field than in Minkowski spacetime. 
Antonino Di Piazza and Giorgio Calucci (Dipartimento di Fisica Teorica   dell'Universita' di Trieste and INFN, Sezione di Tr...