Phase sensitivity of the pair-creation process in colliding laser pulses

We examine the electron-positron pair-creation process from the quantum vacuum triggered by two colliding laser beams in the presence of a nuclear binding potential. Once the two pulses overlap, they form a standing-wave pattern with nodes or antinodes in the region where the nucleus is placed. As the resulting spatial intensity pattern depends on the phase between both fields, it can be used to control the pair-creation yield. It turns out that the ground-state capture of the created electrons can actually be largest for those laser phases that lead to nodes (dark intensity regions) where the nucleus is located and not for those that lead to antinodes (bright intensity regions). Furthermore, this phase can be used to control selectively into which excited state the created electrons are predominately captured.