Pair production at the edge of the QED flux tube
  We investigate the process of Abelian pair production in the presence of strong inhomogeneous and time-dependent external electric fields. The spatial dependence of the external field is motivated by a non-Abelian color flux tube in heavy-ion collisions. We show that the inhomogeneity significantly increase the particle yield compared to that in the commonly used models with a constant and homogeneous field. Moreover our results indicate that in contrast to the latter, most of the particles are produced at the interface of the field profile in accordance with Heisenberg's prediction. 
D\'aniel Ber\'enyi, S\'andor Varr\'o, Vladimir V. Skokov, P\'eter   L\'evai
hep-ph